JP2005227110A - Vibration-type gyro sensor element, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a vibration-type gyro sensor element that is compact and has high sensitivity, and has a cantilever-type vibrator. <P>SOLUTION: A first protective film pattern having a first opening comprising a straight line, in parallel with or vertical to ä110} plane is formed on one main surface of a single-crystal silicon substrate 1, in which the orientation of one main surface or other main surfaces is ä100}. Crystal anisotropic etching is made to the first opening so that the thickness of the vibrator 11 is reached, a straight line in parallel with or vertical with respect to ä110} plane is composed on other main surfaces, in which a lower electrode 4a, a piezoelectric thin film 5a, and upper electrodes 6a, 6b, 6c are formed. A second protective film pattern, having a second opening in which a gap with the vibrator 11 as a cantilever shape has been cut out, is formed, and reactive ion etching is made to the second opening, thus forming the vibrator 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to, for example, an angular velocity sensor used for camera shake detection of a video camera, motion detection in a virtual reality device, direction detection in a car navigation system, and the like, and more specifically, a small vibration type having a cantilever vibrator. The present invention relates to a method for manufacturing a gyro sensor element and a vibration type gyro sensor element.

  Conventionally, as a commercial angular velocity sensor, a cantilever vibrator is vibrated at a predetermined resonance frequency, and the angular velocity is detected by detecting a Coriolis force generated by the influence of the angular velocity with a piezoelectric element or the like. A vibration type gyro sensor (hereinafter referred to as a vibration type gyro sensor) is widely used.

  The vibration-type gyro sensor has advantages such as a simple mechanism, a short start-up time, and low-cost manufacturing. For example, it is mounted on electronic devices such as a video camera, a virtual reality device, and a car navigation system. It is used as a sensor for motion detection and direction detection.

  The vibration type gyro sensor is required to be downsized and improved in accordance with downsizing and high performance of electronic devices to be mounted. For example, in order to increase the functionality of electronic devices, there is a demand to reduce the size by mounting a vibration gyro sensor on one substrate in combination with various sensors used for other purposes.

  However, the vibration type gyro sensor has produced a vibrator by cutting and shaping a piezoelectric material by machining, so that there is a limit to the processing accuracy for downsizing as described above, and the desired performance is achieved. There was a problem that I could not get.

  In view of this, a piezoelectric vibration angular velocity meter, that is, a vibration type gyro sensor, in which a vibrator is manufactured by forming a thin film of a piezoelectric material on a single crystal silicon substrate and miniaturized has been devised (for example, Patent Document 1, Patent). Reference 2).

  In the piezoelectric vibration angular velocity meter shown in Patent Document 1 and Patent Document 2, only crystal anisotropic etching is performed to cut out a cantilever vibrator from a single crystal silicon substrate on which a piezoelectric thin film is formed. The space around the vibrator is secured.

  In Patent Document 1 and Patent Document 2, a silicon (100) plane wafer is used as a silicon single crystal substrate, and a vibrator is formed by creating a mask pattern parallel or perpendicular to the orientation flat of the wafer. It is disclosed. In Patent Documents 1 and 2, a silicon (110) plane wafer is used as a silicon single crystal substrate, and a mask pattern with an angle of 55 degrees or 145 degrees is formed with respect to the orientation flat of the wafer. A method of forming is disclosed.

  However, when the above mask pattern is formed on the silicon (100) plane wafer and the vibrator is formed only by crystal anisotropic etching, the side face of the vibrator has 55 degrees with respect to the (100) plane of the surface ( 111) plane.

  Therefore, the shape of the vibrator is not a quadrangular prism having a right-angled cross-sectional shape, and the vibration type gyro sensor formed in this way narrows the gap around the vibrator due to the inclination of the angle. For this reason, there arises a problem that the sensitivity of the sensor is lowered, a problem that the size reduction is limited, and a problem that the efficiency of vibrating the vibrator is extremely deteriorated.

  On the other hand, when the above mask pattern is formed on the silicon (110) plane wafer and the vibrator is formed only by crystal anisotropic etching, the side face of the vibrator is perpendicular to the (100) plane of the surface (111). ) Surface.

  In this case, the shape of the vibrator can be a quadrangular prism shape as described above, but when a so-called biaxial vibration type gyro sensor that simultaneously detects angular velocities in two directions orthogonal to each other is formed, There is a problem that voids cannot be formed so that the vibrators are orthogonal to each other due to the anisotropy of the orientation.

  A biaxial vibration type gyro sensor produced by forming a vibrator having a quadrangular prism having a right-angled quadrilateral cross section in the same plane using a silicon processing process has been devised (for example, (See Patent Document 3).

  However, Patent Document 3 merely describes the silicon processing process, and does not disclose a specific manufacturing method. Therefore, as described above, it is not possible to form a vibrator having a quadrangular prism with a right-angled quadrilateral cross section in the same plane only by crystal anisotropic etching. A technique for producing a sensor has not yet been disclosed.

Japanese Patent Application Laid-Open No. 8-261762 JP-A-8-327364 Japanese Patent Laid-Open No. 7-190783

  Accordingly, the present invention has been devised to solve the above-described problems, and a method for manufacturing a vibration-type gyro sensor element having a vibrator having a quadrangular prism with a right-angled cross-section and the above-described manufacturing A vibration type gyro sensor element manufactured by the method, and further, a biaxial vibration type gyro sensor element that simultaneously detects angular velocities in two directions by providing the vibrators so as to be orthogonal to each other in the same plane. It is an object of the present invention to provide a vibration gyro sensor element manufactured by the method and the manufacturing method.

  In order to achieve the above object, a method for manufacturing a vibration type gyro sensor element according to the present invention comprises a cantilever-shaped vibrator having a lower electrode, a piezoelectric thin film, and an upper electrode, and the piezoelectric effect of the piezoelectric thin film is obtained. In the manufacturing method of the vibration type gyro sensor element that detects the angular velocity by using the one main surface and the other main surface of the single crystal silicon substrate whose surface orientation is {100}, Forming a first protective film pattern having a first opening constituted by straight or parallel straight lines, and subjecting the first opening to crystal anisotropic etching until the thickness of the vibrator is reached. The lower electrode, the piezoelectric thin film, and the upper electrode are placed in the region to be the vibrator on the other main surface opposite to the one main surface that is crystal anisotropically etched until the thickness of the vibrator is reached. Layered in order The other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed is configured by a straight line parallel or perpendicular to the {110} plane, and the vibrator has the cantilever shape. By forming a second protective film pattern having a second opening formed with a void, and performing reactive ion etching (RIE) on the second opening, the vibrator It is characterized by forming.

  In order to achieve the above object, a vibration type gyro sensor element according to the present invention includes a cantilever-shaped vibrator having a lower electrode, a piezoelectric thin film, and an upper electrode, and utilizes the piezoelectric effect of the piezoelectric thin film. In the vibration type gyro sensor element for detecting the angular velocity, a straight line parallel to or perpendicular to the {110} plane on one main surface of the single crystal silicon substrate in which the surface orientation of the one main surface and the other main surface is {100} Forming a first protective film pattern having a first opening constituted by the step, performing crystal anisotropic etching on the first opening until the thickness of the vibrator is reached, and The lower electrode, the piezoelectric thin film, and the upper electrode are sequentially stacked in the region to be the vibrator on the other main surface opposite to the one main surface that has been crystal anisotropically etched until the thickness is reached. , Lower electrode, above On the other main surface on which the electrothin film and the upper electrode are formed, a gap is formed which is formed by a straight line parallel or perpendicular to the {110} plane, and the vibrator is shaped as a cantilever. A second protective film pattern having a second opening is formed, and reactive ion etching (RIE) is performed on the second opening, thereby providing the vibrator formed. It is characterized by that.

  In order to achieve the above-described object, a method for manufacturing a vibration-type gyro sensor element according to the present invention includes two orthogonal cantilever-shaped vibrators having a lower electrode, a piezoelectric thin film, and an upper electrode. In the method for manufacturing a vibration type gyro sensor element that detects angular velocities in two orthogonal directions using the piezoelectric effect of the first main surface of the single crystal silicon substrate in which the surface orientation of the one main surface and the other main surface is {100} A first protective film pattern having a first opening constituted by a straight line parallel to or perpendicular to the {110} plane is formed on the first opening, and the thickness of the vibrator with respect to the first opening. The crystal anisotropic etching is performed until the thickness of the vibrator becomes the thickness of the vibrator, and the region that becomes the two perpendicular vibrators on the other principal surface opposite to the one principal surface is subjected to the crystal anisotropic etching. Each of the above A pole, the piezoelectric thin film, and the upper electrode are sequentially laminated, and on the other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed, parallel or perpendicular to the {110} plane Forming a second protective film pattern having a second opening formed of a straight line and having the two cantilever-shaped voids orthogonal to the vibrator, and forming the second opening in the second opening On the other hand, two orthogonal transducers are formed by performing reactive ion etching (RIE).

  In order to achieve the above object, a vibration type gyro sensor element according to the present invention includes two orthogonal cantilever-shaped vibrators having a lower electrode, a piezoelectric thin film, and an upper electrode, and the piezoelectric effect of the piezoelectric thin film. In the vibration-type gyro sensor element that detects angular velocities in two orthogonal directions using {110}, {110} is provided on one main surface of a single crystal silicon substrate having a surface orientation of {100} on one main surface and the other main surface. Forming a first protective film pattern having a first opening composed of a straight line parallel or perpendicular to the surface, and anisotropically crystal until the thickness of the vibrator is reached with respect to the first opening. Etching, and anisotropically etching until the thickness of the vibrator becomes the thickness of the vibrator. The piezoelectric thin film, The upper electrode is formed by laminating in order, and the lower electrode, the piezoelectric thin film, and the other main surface on which the upper electrode is formed are configured by straight lines parallel or perpendicular to the {110} plane, A second protective film pattern having a second opening formed by forming a gap having two cantilever shapes orthogonal to the vibrator is formed, and reactive ion etching is performed on the second opening. It is characterized by comprising two orthogonal transducers formed by performing (RIE: Reactive Ion Etching).

  The present invention uses a first protective film pattern having a first opening formed by a straight line perpendicular or parallel to the {110} plane with respect to a single crystal silicon substrate having a {100} plane as a main surface. Crystal oscillator etching is performed, and a resonator is formed by providing a gap around the resonator by reactive ion etching using the second protective film pattern.

  In the vibrator of the vibration type gyro sensor element formed in this way, the fixed end portion for fixing the vibrator as a cantilever is formed with respect to the {100} plane of the other main surface by crystal anisotropic etching. , And a {111} plane having an angle of 55 degrees. As a result, if the difference between the boundary line between the fixed end and the vibrator and the root line of the vibrator defined by reactive ion etching is within 30 μm, the degree of detuning remains very small and constant. Therefore, it is possible to obtain a vibration gyro sensor element with extremely high sensitivity.

  Further, reactive ion is used as a second protective film pattern having a second opening having a void formed so as to form a vibrator in two orthogonal directions by performing crystal anisotropic etching in the above-described plane orientation. By performing etching, it is possible to manufacture a small and high-performance biaxial vibration type gyro sensor element that detects angular velocities in two orthogonal directions.

  Furthermore, the protective film pattern is formed on the front and back surfaces by forming a through hole that serves as a positioning reference when forming the protective film pattern by performing crystal anisotropic etching from the front and back surfaces of the single crystal silicon substrate. Therefore, the vibration type gyro sensor element can be manufactured at a significantly reduced manufacturing cost without using an expensive device.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vibration gyro sensor element manufacturing method and a vibration gyro sensor element according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external perspective view of a vibration type gyro sensor element 10 included in an angular velocity sensor 50 to which the present invention is applied, and FIG. 2 is a diagram illustrating an example of a circuit configuration of the angular velocity sensor 50. For the sake of explanation, a part of the vibration type gyro sensor element 10 shown in FIG.

  As shown in FIG. 1, the vibration gyro sensor element 10 includes a so-called cantilever vibrator 11. The vibrator 11 is formed as a beam having the other end fixed by providing a peripheral space 12 around the vibrator 11 from an element having a thickness t1, a length t2, and a width t3 cut out from the silicon single crystal substrate. The vibrator 11 has a space width of t7b and t7c in a direction perpendicular to the longitudinal direction and a space width of t7a in the longitudinal direction. Note that t7b and t7c have the same length.

  Such a vibrator 11 is formed in a quadrangular prism shape in which a cross-sectional shape when cut along a plane perpendicular to the longitudinal direction is a right-angled quadrilateral.

  The size of the vibration-type gyro sensor element 10 is, for example, as described above, where the element thickness is t1, the element length is t2, and the element width is t3, t1 = 300 μm, t2 = 3 mm, t3 = 1 mm. can do. Further, as shown in FIG. 3, the size of the vibrator 11 at this time is, for example, t4 = 100 μm, t5 when the thickness of the vibrator is t4, the length of the vibrator is t5, and the width of the vibrator is t6. = 2.5 mm and t6 = 100 μm.

  FIG. 4 is a plan view of the vibration type gyro sensor element 10. As shown in FIG. 4, a reference electrode 4a and a piezoelectric body 5a are sequentially stacked on the vibrator 11, and a driving electrode 6a and a pair of detection electrodes 6b are sandwiched between the driving electrode 6a and the piezoelectric body 5a. , 6c are formed in parallel with each other along the longitudinal direction of the vibrator 11 so as not to contact each other. The drive electrode 6a, the detection electrodes 6b and 6c, and the reference electrode 4a are provided with wiring connection terminals A, B, C, and D, respectively.

The piezoelectric body 5a is a thin film made of, for example, piezoelectric ceramics such as lead zirconate titanate (PZT), crystal, piezoelectric single crystal such as LaTaO _3, and the like.

  Such a vibration type gyro sensor element 10 operates by being connected to the IC circuit 40 shown in FIG. 2, and functions as an angular velocity sensor 50 that detects Coriolis force generated according to the angular velocity.

  The IC circuit 40 includes an adder circuit 41, an amplifier circuit 42, a phase shift circuit 43, an AGC (Automatic Gain Control) 44, a differential amplifier circuit 45, a synchronous detection circuit 46, and a smoothing circuit 47. Yes.

  The pair of detection electrodes 6b and 6c of the vibration type gyro sensor element 10 are connected to the adder circuit 41 and the differential amplifier circuit 45 via the wiring connection terminals B and C, respectively. Further, the drive electrode 6 a of the vibration type gyro sensor element 10 is connected to the output end of the AGC 44 via the wiring connection terminal A.

  In the angular velocity sensor 50, a so-called phase shift oscillation circuit is configured by the addition circuit 41, the amplification circuit 42, the phase shift circuit 43, the AGC 44, and the vibration type gyro sensor element 10, and the vibration type gyro sensor element 10 is formed by this phase shift oscillation circuit. A voltage is applied between the reference electrode 4a and the drive electrode 6a to cause the vibrator 11 to self-oscillate. The vibration direction of the vibrator 11 is the thickness direction of the vibrator 11.

  Further, in the angular velocity sensor 50, the output terminal of the adder circuit 41 and the differential amplifier circuit 45 in which the pair of detection electrodes 6b and 6c are connected via the wiring connection terminals B and C are connected to the synchronous detection circuit 46, The synchronous detection circuit 46 is connected to the smoothing circuit 47, and these and the piezoelectric body 5a function as a detection unit that detects the angular velocity of the vibrator 11.

  That is, in the angular velocity sensor 50 shown in FIG. 2, the angular velocity is applied in the longitudinal direction of the vibrator 11 when the vibrator 11 of the vibration type gyro sensor element 10 is self-excited by the phase-shift oscillation circuit described above. Then, the Coriolis force generated in the direction perpendicular to the vibration direction is detected by the piezoelectric body 5 a, output as signals having opposite polarities from the detection electrodes 6 b and 6 c, and input to the differential amplifier circuit 45. The output amplified by the differential amplifier circuit 45 is input to the synchronous detection circuit 46, where synchronous detection is performed. At this time, the output from the adder 41 is supplied to the synchronous detection circuit 46 as a synchronous signal in order to perform synchronous detection. The output from the synchronous detection circuit 46 is output as an angular velocity signal that is a DC signal obtained by detecting the Coriolis force generated in the vibrator 11 via the smoothing circuit 47.

  As described above, in the angular velocity sensor 50, the vibrator 11 is vibrated using the piezoelectric body 5a, the Coriolis force generated in the vibrator 11 is detected by the piezoelectric body 5a, and the Coriolis force detected by the piezoelectric body 5a is detected. Based on this, the angular velocity can be detected.

(Example)
Subsequently, as an example, the vibration gyro sensor element 10 described above is actually manufactured, and a manufacturing method thereof will be described.

  As described above, the vibration type gyro sensor element 10 shown in FIG. 1 is formed by processing a single crystal silicon substrate.

FIG. 5 is a plan view of the single crystal silicon substrate 1 used when forming the vibration-type gyro sensor element 10, and FIG. 6 is a cross-sectional view of the single crystal silicon substrate 1 shown in FIG. . One main surface 1B and the other main surface 1A of the single crystal silicon substrate 1 are thermally oxidized to form a SiO ₂ film as a protective film during crystal anisotropic etching described later.

  As shown in FIG. 5, the single crystal silicon substrate 1 used in the vibration type gyro sensor element 10 has a {100} plane orientation of one main surface 1B of the single crystal silicon substrate 1, and a side surface 1C as shown in FIG. Is cut out so that the plane orientation of {110} is. Since the other main surface 1A is parallel to the one main surface 1B, the surface orientation of the other main surface 1A is also {100}.

  However, “{}” is a symbol for collectively representing equivalent plane orientations having different directions. For example, {100} is a generic name for (100), (010), (001), and the like. Shall.

  Thus, the size of the single crystal silicon substrate 1 cut out by defining the crystal plane orientation is arbitrarily set according to the apparatus provided in the processing process line. For example, in the present embodiment, a single crystal silicon substrate 1 having a length × width of 3 cm × 3 cm square is used.

  Further, the thickness of the single crystal silicon substrate 1 is determined by workability and the price of the substrate, but may be at least equal to or greater than the thickness of the vibrator 11 formed in the vibration type gyro sensor element 10. For example, in this embodiment, as shown in FIG. 3, the thickness t4 of the vibrator 11 is set to 100 μm, so the thickness of the single crystal silicon substrate 1 is set to 300 μm, which is three times.

As shown in FIG. 6, thermal oxide films 2A and 2B, which are SiO ₂ films, are formed on the other main surface 1A and one main surface 1B of the single crystal silicon substrate 1 by thermal oxidation. The thermal oxide films 2A and 2B function as protective films when performing crystal anisotropic etching described later. The thickness of the thermal oxide films 2A and 2B is arbitrary, but is 0.1 μm in this embodiment. In addition, the single crystal silicon substrate 1 used in this embodiment adopts an N type as a conduction type, but can be arbitrarily determined.

  In the following description, in the single crystal silicon substrate 1, the other main surface 1A side on which the thermal oxide film 2A is formed is the front surface, and the one main surface 1B side on which the thermal oxide film 2B is formed is the back surface.

  Using such a single crystal silicon substrate 1, first, the thermal oxide film 2 </ b> B formed on the back surface of the single crystal silicon substrate 1 where crystal anisotropic etching is performed is removed by photoetching.

  Photoetching is largely divided into a process (photolithography) for forming a resist film pattern with openings to be removed on the thermal oxide film 2B and a process (etching) for removing the thermal oxide film 2B using the pattern. Separated.

  FIG. 7 is a plan view showing a state in which the resist film pattern 3 is formed on the thermal oxide film 2B of the single crystal silicon substrate 1, and FIG. 8 shows the single crystal silicon substrate 1 shown in FIG. It is sectional drawing at the time of cut | disconnecting.

  As shown in FIG. 7, in the resist film pattern 3 formed on the thermal oxide film 2B, the length in the direction perpendicular to the {110} plane is t8, and the length in the direction parallel to the {110} plane is t9. The openings 3a having a rectangular shape of t8 × t9 are regularly arranged with a predetermined interval. In the present embodiment, a pattern in which 3 × 5 openings 3a are formed. Each of the openings 3 a becomes one vibration type gyro sensor element 10.

  This resist film pattern 3 is made of a photosensitive resin after pre-baking to remove moisture by heating the thermal oxide film 2B with microwaves in exactly the same manner as photolithography used in the semiconductor processing process. It is formed by applying a photoresist film, exposing the photoresist film to a mask on which the pattern for forming the opening 3a is formed, and developing the mask.

  T8 and t9 which determine the size of the opening 3a are the shape of the vibrator 11 of the vibration type gyro sensor element 10, the thickness t1 of the single crystal silicon substrate 10, and the spatial widths t7a, t7b of the vibrator shown in FIG. determined by t7c. Specific values of t8 and t9 will be described later in detail.

  In this manner, as shown in FIG. 8, a resist film pattern 3 is formed on the thermal oxide film 2B of the single crystal silicon substrate 1.

  Subsequently, the thermal oxide film 2B in the opening 3a formed by the resist film pattern 3 is removed by etching. FIG. 9 is a plan view showing a state of the single crystal silicon substrate 1 from which only the thermal oxide film 2B at the opening 3a formed by the resist film pattern 3 has been removed, and FIG. 10 is shown in FIG. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate 1 by XX line.

  Etching for removing the thermal oxide film 2B may be physical etching such as ion etching or wet etching, but considering the smoothness of the interface of the single crystal silicon substrate 1, only the thermal oxide film 2B is removed. Wet etching is preferred.

  In this example, ammonium fluoride was used as a chemical solution for wet etching. However, in the case of wet etching, when etching is performed for a long time, etching proceeds from the side surface of the opening portion, so-called side etching becomes large. Therefore, the etching is finished so that only the opening portion 3a of the thermal oxide film 2B is removed. Control time accurately.

  In this way, the thermal oxide film 2B located in the opening 3a of the resist film pattern 3 is removed as shown in FIG.

  Subsequently, by removing the thermal oxide film 2B by the above-described etching, single crystal silicon in which the {100} plane is exposed at the opening 2Ba of t8 × t9 having the same size as the opening 3a of the resist film pattern 3 The substrate 1 is subjected to wet etching, and the thickness of the single crystal silicon substrate 1 is cut down to t4 which is the thickness of the vibrator 11.

  FIG. 11 is a plan view showing a state in which the thermal oxide film 2B is removed from the single crystal silicon substrate 1 and only the opening 2Ba having a size of t8 × t9 where the {100} plane is exposed is etched. 12 is a cross-sectional view of the single crystal silicon substrate 1 shown in FIG. 11 taken along the line XX. FIG. 13 is an enlarged view of the area A shown in FIG.

  Here, the wet etching performed on the single crystal silicon substrate 1 is crystal anisotropic etching utilizing the property that the etching rate depends on the crystal direction. When the anisotropic oxide etching is performed on the opening 2Ba where the thermal oxide film 2B is removed and the {100} plane is exposed, an angle of about 55 degrees with respect to the {100} plane is obtained as shown in FIG. The {111} plane that becomes the plane orientation appears, and the etching is finished so as to ensure t4 which is the thickness of the vibrator 11, so that a so-called diaphragm shape is obtained.

  In general, single crystal silicon has an etching rate dependency with respect to a crystal direction that a {111} plane is very difficult to be etched compared to a {100} plane because of its crystal structure. Specifically, the etching rate of {100} plane of single crystal silicon is about 200 times the etching rate of {111} plane.

  Etching solutions that can be used when crystal anisotropic etching is performed on single crystal silicon include TMAH (tetramethylammonium hydroxide), KOH (potassium hydroxide), EDP (ethylenediamine-pyrocatechol-water), humanradine, etc. It is.

  In this example, a TMAH (tetramethylammonium hydroxide) 20% solution in which the selectivity of the etching rate between the thermal oxide film 2A and the thermal oxide film 2B is larger is used as the etchant. During etching, the temperature is kept at 80 ° C. while stirring the etching solution, and the diaphragm depth t10 is 200 μm over 6 hours, that is, the thickness t11 of the single crystal silicon substrate 1 remaining after etching is the thickness t4 of the vibrator 11. Etching was performed until the thickness became 100 μm.

  Here, in order to perform crystal anisotropic etching, numerical values of t8 and t9 that define the size of the opening 3a formed by the resist film pattern 3 described with reference to FIG. 7 will be specifically described.

  The width t9 of the opening 3a, that is, the width of the diaphragm after etching is t9 = t9a + t9b + t9c as shown in FIG.

  t9c can be expressed as t9c = t6 + t7b + t7c using the width t6 of the vibrator 11 shown in FIG. 3 and the space widths t7b and t7c of the surrounding space 12 formed around the vibrator 11 shown in FIG. .

  Further, t9a and t9b have the same length, and as shown in FIG. 13, the {111} plane that appears when the crystal anisotropic etching is performed and the back surface of the single crystal silicon substrate 1 {100} Since the surface forms an angle of 55 degrees, it can be expressed as t9a = t9b = t10 × 1 / tan55 ° using the depth t10 of the diaphragm.

  Accordingly, the width t9 of the opening 3a is t9 = {t10 × 1 / tan55 °} × 2 + (t6 + t7b + t7c). Here, when t6 = 100 μm, t7b = t7c = 200 μm, and t10 = 200 μm, t9 = 780 μm.

  When the crystalline anisotropic etching as described above is performed, a {111} plane that forms an angle of 55 degrees with the {100} plane appears in the t8 direction in the opening 3a of the resist film pattern 3 as in the t9 direction. Therefore, the length t8 of the opening, that is, the length of the diaphragm after etching is the length t5 of the vibrator 11 shown in FIG. 3, and the space of the surrounding space 12 formed around the vibrator 11 shown in FIG. Using the width t7a, t8 = {t10 × 1 / tan55 °} × 2 + (t5 + t7a). Here, when t5 = 2.5 mm, t7a = 200 μm, and t10 = 200 μm, t8 = 2980 μm.

  In the above description, the entire single crystal silicon substrate 1 has been described with reference to the drawings. However, for convenience of description, in the following description, only the single crystal silicon substrate 1 on which the diaphragm shown as the region W in FIG. This will be explained using. Further, in the following description, since it is a processing process for the thermal oxide film 2A side, a plan view with the thermal oxide film 2A side as a top surface and a cross-sectional view of this plan view cut at a predetermined position is used. Explain.

  Specifically, when the single crystal silicon substrate 1 on which the diaphragm in the region W shown in FIG. 11 is formed has the thermal oxide film 2A as an upper surface, a plan view as shown in FIG. Is as shown in FIG.

  Subsequently, a lower electrode film, a piezoelectric film, and an upper electrode film are formed on the thermal oxide film 2A to form the reference electrode 4a, the piezoelectric body 5a, the drive electrode 6a, and the detection electrodes 6b and 6c shown in FIG. To do. When the lower electrode film 4, the piezoelectric film 5, and the upper electrode film 6 are sequentially formed on the thermal oxide film 2A of the single crystal silicon substrate 1, the plan view is as shown in FIG. The cut sectional view is as shown in FIG.

  In this example, the lower electrode film 4, the piezoelectric film 5, and the upper electrode film 6 were all formed using a magnetron sputtering apparatus.

  First, the lower electrode film 4 is formed on the thermal oxide film 2A. In this example, first, the conditions of the magnetron sputtering apparatus were set to gas pressure: 0.5 Pa, RF power: 1 kW, and titanium (Ti) was formed on the thermal oxide film 2A so as to have a film thickness of 50 nm. Subsequently, platinum (Pt) was formed on the formed titanium (Ti) so that the film thickness was 200 nm under the apparatus conditions of gas pressure: 0.5 Pa and RF power: 0.5 kW. That is, the lower electrode film 4 is formed by depositing titanium and platinum to the above thickness.

Next, a piezoelectric film 5 is formed on the lower electrode film 4. In this example, first, Pb _{(1 + x)} (Zr _0.53 Ti _0.47 ) O _3-y oxide was used as a target, and the conditions of the magnetron sputtering apparatus were normal temperature, gas pressure: 0.7 Pa, RF power. : A piezoelectric thin film of lead zirconate titanate (PZT) was formed on platinum (Pt) formed as the lower layer electrode 4 so as to have a thickness of 1 μm at 0.5 kW. Subsequently, the single crystal silicon substrate 1 on which lead zirconate titanate (PZT) is formed is placed in an electric furnace, and a crystallization heat treatment is performed in an oxygen atmosphere at 700 ° C. for 10 minutes to form the piezoelectric film 5. did.

  Finally, the upper electrode film 6 is formed on the piezoelectric film 5. In this example, the conditions of the magnetron sputtering apparatus were such that the gas pressure was 0.5 Pa and the RF power was 0.5 kW, and platinum (Pt) was formed on the piezoelectric film 5 so that the film pressure was 200 nm.

  Next, the upper electrode film 6 is processed to form drive electrodes 6a and detection electrodes 6b and 6c. 18 is a plan view showing a state of the single crystal silicon substrate 1 on which the drive electrodes 6a and the detection electrodes 6b and 6c are formed. FIG. 19 is a cross-sectional view of the single crystal silicon substrate 1 shown in FIG. It is sectional drawing at the time of doing.

  The drive electrode 6 a is an electrode for applying a voltage for driving the vibrator 11 as described above, and is formed to be the center of the vibrator 11. The detection electrodes 6b and 6c are electrodes for detecting the Coriolis force generated in the vibrator 11 as described above, and are parallel to the drive electrode 6a and do not contact with the drive electrode 6a. Formed on the vibrator 11.

As shown in FIG. 18, the drive electrode 6a and the detection electrodes 6b, 6c are formed so that one end thereof coincides with the root line R that is the root of the vibrator 11, and the one end of each electrode is formed. Terminal junctions 6a ₁ , 6b ₁ , 6c ₁ are formed in the parts, respectively.

In the present embodiment, the width t13 of the drive electrode 6a is 50 μm, the width t14 of the detection electrodes 6b and 6c is 10 μm, the length t12 of the drive electrode 6a and the detection electrodes 6b and 6c is 2 mm, and the drive electrode 6a of the detection electrodes 6b and 6c. The distance t15 between each of the two was 5 μm. The drive electrode 6a and the detection electrodes 6b and 6c can be designed to have any size as long as they are formed on the vibrator 11. In this embodiment, the length t16 of each of the terminal joint portions 6a ₁ , 6b ₁ , 6c ₁ is 50 μm, and the width t17 is 50 μm.

In this embodiment, the drive electrode 6a, the detection electrodes 6b and 6c, and the terminal junctions 6a ₁ , 6b ₁ and 6c ₁ are formed on the upper electrode film 6 by using a photolithography technique, and then ion ions are formed. An unnecessary portion of the electrode film 6 was removed by etching.

The present invention is not limited to the method for forming the drive electrode 6a, the detection electrodes 6b and 6c, and the terminal joints 6a ₁ , 6b ₁ and 6c _1, and various methods other than the above-described methods can be used. Can be applied.

  Next, the piezoelectric film 5 is processed to form a piezoelectric body 5 a on the vibrator 11. 20 is a plan view showing a state of the single crystal silicon substrate 1 on which the piezoelectric body 5a is formed by processing the piezoelectric film 5, and FIG. 21 shows the single crystal silicon substrate 1 shown in FIG. It is sectional drawing at the time of cut | disconnecting.

  The piezoelectric body 5a may have any shape as long as it completely covers the drive electrode 6a and the detection electrodes 6b and 6c formed by processing the upper electrode film 6.

  In this embodiment, the length t18 of the piezoelectric body 5a is 2.2 mm, and the width t19 is 90 μm. The piezoelectric body 5 a having such a size is arranged such that its center coincides with the center of the vibrator 11 and one end thereof coincides with the root line R that is the root of the vibrator 11.

The width t18 of the piezoelectric body 5a needs to be equal to or smaller than the width t4 of the vibrator 11. Further, in this embodiment, the piezoelectric film 5 is provided under the terminal joint portions 6a ₁ , 6b ₁ , 6c ₁ described above, and a width of 5 μm is provided from each outer periphery of the terminal joint portions 6a ₁ , 6b ₁ , 6c _1. It is left. The piezoelectric film 5 remaining under the terminal joints 6a ₁ , 6b ₁ , 6c ₁ is arbitrarily set depending on the overall shape size of the vibration type gyro sensor element 10.

In this embodiment, a photolithography technique is used to form a resist film pattern in the shape of the piezoelectric film 5 to be left under the piezoelectric body 5a and the terminal joints 6a ₁ , 6b ₁ , 6c ₁ , and then wet using a hydrofluoric acid solution. The piezoelectric body 5a was formed by removing the unnecessary portion of the piezoelectric film 5 by etching.

  As described above, in this embodiment, the technique for removing unnecessary portions of the piezoelectric film 5 in order to form the piezoelectric body 5a is wet etching. However, the present invention is not limited to this, and is physically limited. A removal method using ion etching, which is an effective etching, or a removal method using reactive ion etching (RIE) that performs etching by chemical action and physical action can be applied.

  Next, the lower electrode film 4 is processed to form the reference electrode 4 a on the vibrator 11. FIG. 22 is a plan view showing a state of the single crystal silicon substrate 1 on which the reference electrode 4a is formed by processing the lower electrode film 4, and FIG. 23 shows the single crystal silicon substrate 1 shown in FIG. It is sectional drawing at the time of cut | disconnecting by.

  The reference electrode 4a may have any shape as long as it completely covers the piezoelectric body 5a formed by processing the piezoelectric film 5.

  In this example, the length t20 of the reference electrode 4a was 2.3 mm, and the width t21 was 94 μm. Such a reference electrode 4 a has its center coincident with the center of the vibrator 11 and one end thereof coincides with the root line R that is the root of the vibrator 11.

  The width t20 of the reference electrode 4a needs to be equal to or smaller than the width t4 of the vibrator 11. In this embodiment, the lower electrode film 4 under the piezoelectric film 5 that has not been removed as described above is left with a width of 5 μm from the outer periphery of the piezoelectric film 5. This width is arbitrarily set depending on the overall shape size of the vibration type gyro sensor element 10.

  Further, in order to electrically connect the reference electrode 4a and the outside, a wiring connection terminal D is formed by the lower electrode film 4 as shown in FIG. As described above, the reference electrode 4 a and the wiring connection terminal D are electrically connected via the lower electrode film 4 left under the piezoelectric film 5.

  In this embodiment, since it is assumed that the electrical connection between the vibration type gyro sensor element 10 and the outside is performed by wire bonding, a terminal portion to be actually wired of the wiring connection terminal D is necessary at the time of wire bonding. Secure only the required area.

  In this embodiment, the length t22 of the terminal portion of the wiring connection terminal D is 200 μm, and the width t23 is 100 μm. The bonding of the vibration type gyro sensor element 10 to the outside is arbitrary including the bonding method, and the shape of the wiring connection terminal D is set to be optimum according to the bonding method employed.

  In this embodiment, a resist film pattern having a shape as shown in FIG. 22 is formed by using a photolithography technique, and then unnecessary portions of the lower electrode film 4 are removed by ion etching, whereby the reference electrode 4a and the wiring are formed. The lower electrode film 4 for electrically connecting the connection terminal D, the reference electrode 4a and the wiring connection terminal D was formed.

  As described above, in this embodiment, the technique for removing unnecessary portions of the lower electrode film 4 to form the reference electrode 4a is ion etching, which is physical etching. However, the present invention is not limited to this. Instead, it is possible to apply a removal method by wet etching, which is chemical etching, or reactive ion etching (RIE), in which etching is performed by chemical action and physical action.

Next, electrical connection between the terminal connection portions 6a ₁ , 6b ₁ , 6c ₁ formed on one end side of each of the drive electrode 6a and the detection electrodes 6b, 6c and the wiring connection terminals A, B, C is performed. A planarizing resist film 7 is formed for smoothness.

  24 is a plan view showing a state of the single crystal silicon substrate 1 on which the planarizing resist film 7 is formed, and FIG. 25 is a cross-sectional view when the single crystal silicon substrate 1 shown in FIG. 24 is cut along a YY line. FIG.

As shown in FIG. 22 described above, when the wiring connection terminals A, B, and C and the terminal joint portions 6a ₁ , 6b ₁ , and 6c ₁ are physically joined, the piezoelectric body 5a is formed. It must pass through the remaining end of the piezoelectric film 5 and the end of the lower electrode film 4 left when the reference electrode 4a is formed.

In this embodiment, the piezoelectric body 5a is formed by etching the piezoelectric film 5 by wet etching, and the etched end portion has a reverse taper shape or a vertical shape in the direction of the single crystal silicon substrate 1. It has become. Therefore, if the wiring film is formed so as to electrically connect the terminal junctions 6a ₁ , 6b ₁ , 6c ₁ and the wiring connection terminals A, B, C without forming the planarizing resist film 7, There is a possibility that the electrical connection is broken by the step of the end portion.

  Further, since the end portion of the lower electrode film 4 electrically connected to the reference electrode 4a is exposed, the drive electrode 6a, the detection electrodes 6b and 6c, and the reference electrode are formed unless the planarizing resist film 7 is formed. 4a will be short-circuited.

For the reasons described above, as shown in FIG. 24, a planarizing resist film 7 is formed on the terminal junctions 6a ₁ , 6b ₁ , 6c ₁ to eliminate the step at the end of the piezoelectric film 5, and the lower electrode The end of the film 4 is not exposed.

  The shape of the flattening resist film 7 can be arbitrarily set as long as it eliminates the step at the end of the piezoelectric film 5 and does not expose the end of the lower electrode film 4 as described above. In this embodiment, the planarizing resist film 7 has a width t24 of 200 μm and a length t25 of 50 μm.

  The planarization resist film 7 is hardened by applying a heat treatment of about 280 to 300 ° C. to a resist film patterned in a desired shape at a position shown in FIG. 24 by a photolithography technique. In this embodiment, the thickness of the resist film is about 2 μm, but this thickness is preferably changed according to the thicknesses of the piezoelectric film 5 and the lower electrode film 4 to be equal to or greater than the total thickness of both. In this embodiment, the planarization resist film 7 is formed using a resist film. However, any non-conductive material that can avoid the above-described reason is arbitrary including its formation method. .

  Next, wiring connection terminals A, B, and C used when wiring processing for connecting the drive electrode 6a and the detection electrodes 6b and 6c to the outside are performed. 26 is a plan view showing a state of the single crystal silicon substrate 1 on which the wiring connection terminals A, B, and C are formed, and FIG. 27 is a view when the single crystal silicon substrate 1 shown in FIG. 26 is cut along the YY line. FIG.

The wiring connection terminals A, B, and C shown in FIG. 26 are connected to the terminal junctions 6a ₁ , 6b ₁ , and 6c ₁ of the drive electrode 6a and the detection electrodes 6b and 6c, respectively. In this embodiment, since the electrical connection between the vibration type gyro sensor element 10 and the outside is assumed to be performed by wire bonding, the terminal portions of the wiring connection terminals A, B, and C that are actually wired are used. As in the case of the wiring connection terminal D described above, an area required for wire bonding is secured.

Each wiring connection terminal A, B, C is formed on the thermal oxide film 2A so as to pass through the upper surface of the planarization resist film 7 and to be in contact with the terminal junctions 6a ₁ , 6b ₁ , 6c ₁ , respectively. The shape of each electrode joint, which is a joint between the wiring connection terminals A, B, and C, and the terminal connections 6a ₁ , 6b ₁ , and 6c ₁ is arbitrary, but is 5 μm in order to reduce electrical contact resistance. A size of 4 or more is desirable.

  In the wiring connection terminals A, B, and C, the terminal portion to which the wiring is actually connected has a shape that can secure an area necessary for wire bonding bonding as described above.

  In the present embodiment, the length t26 of each of the wiring connection terminals A, B, and C is 200 μm, and the width t27 is 100 μm. The bonding of the vibration type gyro sensor element 10 to the outside is arbitrary including the bonding method, and the shape of the wiring connection terminals A, B, and C is set to be optimal according to the bonding method to be employed.

  In this example, a resist film pattern having a shape as shown in FIG. 26 was formed by using a photolithography technique, and then wiring connection terminals A, B, and C were formed by sputtering. When sputtering, the film adhering to unnecessary portions was removed by a so-called lift-off technique, which is simultaneously removed when removing the resist film pattern.

  Specifically, for the wiring connection terminals A, B, and C, titanium (Ti) for improving adhesion is deposited by 20 nm, copper (Cu) having low electrical resistance and low cost is deposited by 300 nm, Further, in order to facilitate bonding with wire bonding, gold (Au) was formed by depositing 300 nm. Note that the material used when forming the wiring connection terminals A, B, and C and the formation method of the wiring connection terminals A, B, and C are arbitrary, and the present invention is not limited to the materials and the formation method. Absent.

  The subsequent process is a process of manufacturing the cantilever vibrator 11 by forming the surrounding space 12 with respect to the vibration type gyro sensor 10 as shown in FIG. FIG. 28 is a plan view showing a state where the cantilever vibrator 11 is formed by forming the surrounding space 12 in the single crystal silicon substrate 1, and FIG. 29 is a single crystal silicon substrate shown in FIG. 1 is a cross-sectional view showing a state where 1 is cut along a YY line, and FIG. 30 is a cross-sectional view showing a state where the single crystal silicon substrate 1 shown in FIG. 28 is cut along an XX line.

  As shown in FIG. 28, the surrounding space 12 includes a space having a width of t7b and t7c in the left and right directions from the side surface of the vibrator 11 on the side where the detection electrodes 6b and 6c are formed, and a longitudinal direction of the vibrator 11. Thus, a space having a so-called “U” shape is formed by a space having a width of t7a on the end side opposite to the root line R of the vibrator 11.

  In this embodiment, t7b and t7c are each 200 μm. These t7b and t7c are determined by the state of the gas in the surrounding space 12, the Q value indicating the required quality of vibration of the vibrator 11, and the like.

  In this embodiment, first, using a photolithography technique, a “U” -shaped resist film pattern as shown in FIG. 28 is formed on the thermal oxide film 2A, and then the thermal oxide film 2A is ion-etched. Remove with. In order to remove the thermal oxide film 2A, wet etching can be performed, but ion etching is preferable in consideration of a dimensional error caused by side etching.

  Then, the surrounding space 12 is formed by etching and penetrating the "U" -shaped single crystal silicon substrate 1 from which the thermal oxide film 2A has been removed by reactive ion etching (RIE). To do.

  In this embodiment, using an etching apparatus equipped with inductively coupled plasma (ICP), an etching process and a process of forming a sidewall protective film for protecting the sidewall at the etched portion are repeated. A vibrator 11 having a vertical side wall surface was formed by a process (Bosch).

By using this Bosch process, a high-density plasma is generated by ICP, and SF ₆ for etching and C ₄ F ₈ gas for side wall protection are alternately introduced, and about 10 μm per minute. The vibrator 11 having a vertical side wall surface can be formed while etching at a speed.

  With the above process, the main steps of piezoelectric element formation, shape formation, and wiring formation relating to the formation of the vibration type gyro sensor element 10 are completed. For example, as shown in FIG. A plurality of gyro sensor elements 10, here 5 × 3, are formed.

  The number of vibration-type gyro sensor elements 10 formed in one single crystal silicon substrate 1 is not limited to 5 × 3 as shown in FIG. 31, and the size of the vibration-type gyro sensor element 10 to be designed, It is determined by each pitch when forming.

  In the next step, the plurality of vibration gyro sensor elements 10 thus formed on the single crystal silicon substrate 1 are cut into a single element. The method and dimensions for dividing the vibration type gyro sensor element 10 from the single crystal silicon substrate 1 are not particularly determined, and the shape after the division is also arbitrary.

  In the present embodiment, the single crystal silicon substrate 1 was directly folded by hand and the vibration gyro sensor element 10 was taken out after being cut with a diamond cutter so as to trace the element cutting line 20 shown in FIG. . An arbitrary method can be applied to the method of dividing the single crystal silicon substrate 1. For example, a method of grinding with a grindstone or cutting using the plane orientation of the single crystal silicon substrate 1 may be used.

  Subsequently, as shown in FIG. 33, the vibration-type gyro sensor element 10 divided individually is attached to the IC substrate 21. The vibration gyro sensor element 10 and the IC substrate 21 can be attached by any method, but in this embodiment, the vibration gyro sensor element 10 is attached using an anaerobic adhesive.

  After the vibration type gyro sensor element 10 is attached to the IC substrate 21, electrical connection is performed. On the IC substrate 21, the IC circuit 40 described with reference to FIG. 2 at the beginning is mounted. Further, the IC substrate 21 includes a substrate terminal 22a connected to the end of the AGC 44 shown in FIG. 2, substrate terminals 22b and 22c connected to the synchronous detection circuit 45, and a substrate terminal 22d connected to a reference electrode (not shown). Is formed.

  In the present embodiment, the wiring connection terminals A, B, C, and D of the vibration type gyro sensor element 10 and the substrate terminals 22a, 22b, 22c, and 22d in the IC substrate 21 are electrically connected using a wire bonding method. Connection was made. This connection method is also arbitrary, and a method of forming conductive bumps used in semiconductors can also be used.

  Next, as shown in FIG. 34, a cover member 30 is attached to protect the vibration type gyro sensor element 10 and the circuit on the IC substrate 21 from contact with the outside to protect them. The material of the cover member 30 is arbitrary, but it is desirable to have a shielding effect such as SUS in consideration of the influence of external noise. The cover material 30 needs to have a shape that does not hinder the vibration of the vibrator 11. In this way, the angular velocity sensor 50 is formed.

  In this way, when a voltage is applied to the drive electrode 6a of the vibrator 11 included in the vibration type gyro sensor element 10 constituting the angular velocity sensor 50 to vibrate at a predetermined resonance frequency, the vibrator 11 It resonates at the longitudinal resonance frequency in the thickness direction, and at the transverse resonance frequency in the transverse direction, which is the width direction of the vibrator 11.

  At this time, the smaller the degree of detuning, which is the difference between the longitudinal resonance frequency and the transverse resonance frequency, the higher the sensitivity of the vibration gyro sensor element 10. Therefore, in order to increase the sensitivity of the vibration type gyro sensor element 10, it is necessary to design the vibrator 11 so that the degree of detuning is reduced. For example, the length of the vibrator 11, that is, t5 shown in FIG. 3 is likely to affect the longitudinal resonance frequency, and the root line R that determines the length of the vibrator 11 shown in FIG. b) As shown in FIG. 35 (c), a {111} plane that is an inclined plane that forms an angle of 55 degrees with the {100} plane of the diaphragm formed when crystal anisotropic etching is performed, and a flat plane There is a problem that the degree of detuning increases according to the amount of deviation.

  The boundary line K shown in FIG. 35B indicates that the boundary line R is shifted in the positive direction of the Y axis, that is, in the root side direction of the vibrator 11, and FIG. A boundary line K shown indicates that the Y axis is shifted in the negative direction, that is, in the direction opposite to the root of the vibrator 11.

  As shown in FIG. 35B, when the boundary line K is displaced in the positive direction of the Y axis with respect to the root line R, the vibration type gyro sensor element 10 has a shape as shown in a perspective view of FIG. Become. Further, as shown in FIG. 35C, when the boundary line K is shifted in the negative direction of the Y axis with respect to the root line R, the vibration type gyro sensor element 10 is as shown in a perspective view in FIG. It becomes a shape.

  Such a deviation between the root line R and the boundary line K is the position of the resist film pattern 3 formed on the thermal oxide film 2B on the back surface side of the single crystal silicon substrate 1 when crystal anisotropic etching is performed. This is because the position of the resist film pattern formed on the surface side is shifted when reactive ion etching is performed.

  The positional deviation of the resist film pattern formed on the front and back surfaces of the single crystal silicon substrate 1 is, for example, a double-side aligner device that can simultaneously observe the front and back surfaces of the single crystal silicon substrate 1, a pattern or marker on one side of the single crystal silicon substrate 1. With reference to the above, a slight improvement can be achieved by an alignment apparatus that performs position regulation on the other surface. However, even when such an apparatus is used, it is very difficult to completely eliminate the deviation between the root line R and the boundary line K.

  FIG. 38 shows the relationship between the longitudinal resonance frequency and the transverse resonance frequency with respect to the deviation amount of the boundary line K from the root line R in the vibration type gyro sensor element 10.

  As shown in FIG. 38, in the vibration type gyro sensor element 10, in the range where the deviation amount between the root line R and the boundary line K is 0 μm to 30 μm, the longitudinal resonance frequency and the transverse resonance frequency are approximately 35 kHz. It can be seen that the degree of detuning is small. It can be seen that when the deviation between the root line R and the boundary line K exceeds 30 μm, only the longitudinal resonance frequency gradually decreases and the degree of detuning increases. Similarly, when the deviation amount between the root line R and the boundary line K is in the range from −30 μm to 0 μm, the longitudinal resonance frequency and the transverse resonance frequency are almost the same at 35 kHz, and the degree of detuning is small. I understand. It can be seen that when the deviation between the root line R and the boundary line K exceeds −30 μm, only the longitudinal resonance frequency gradually increases and the degree of detuning increases.

  This is because when the deviation between the root line R and the boundary line K exceeds ± 30 μm, that is, when the difference between the root line R and the boundary line K exceeds 30 μm, the root line R side of the vibrator 11 This is considered to be due to the fact that the restraint at the point is released from the substrate supporting the vibrator 11.

  As a comparative example, FIG. 38 shows an inclined surface {111} having an angle of 55 degrees with the {100} surface of the diaphragm formed in the vibration type gyro sensor element 10 as shown in FIGS. } In the vibration type gyro sensor element 100 in which the surface is not formed and the side surface of the substrate supporting the vibrator is vertical, the longitudinal resonance frequency and the lateral resonance frequency with respect to the deviation amount of the boundary line K from the root line R The relationship was shown. 39 is a perspective view of the vibration-type gyro sensor element 100 in which the boundary line K is shifted in the positive direction of the Y axis with respect to the root line R. FIG. 40 is a perspective view of the boundary line K in the root line R. It is a perspective view of the vibration type gyro sensor element 100 shifted in the negative direction of the Y axis.

  As shown in FIG. 38, in the vibration type gyro sensor element 100, in the range where the deviation amount between the root line R and the boundary line K is 0 μm to 30 μm, the longitudinal resonance frequency and the transverse resonance frequency are approximately 35 kHz. It can be seen that the degree of detuning is small. It can be seen that when the deviation between the root line R and the boundary line K exceeds 30 μm, only the longitudinal resonance frequency gradually decreases and the degree of detuning increases. On the other hand, when the amount of deviation between the root line R and the boundary line K changes in the negative direction, it can be seen that only the longitudinal resonance frequency is increased and the degree of detuning is increased.

  Therefore, as described above, the vibration-type gyro sensor element 10 manufactured by forming the vibrator 11 from the single crystal silicon substrate 1 by performing crystal anisotropic etching and reactive ion etching includes the root line R, Since the amount of deviation (difference) from the boundary line K can be within an allowable range up to 30 μm, the gyro sensor is very sensitive without using the above-described expensive device.

  On the other hand, in the vibration type gyro sensor element 100 shown in FIG. 39 and FIG. 40 in which the inclined surface is not formed on the base body, when the boundary line K is shifted in the minus direction with respect to the root line R, the amount of shift described above. Has no tolerance at all. Therefore, it is obvious that considerable precision is required in the manufacturing process, and many problems such as difficulty in mass production and increase in manufacturing cost remain.

  By the way, as described above, in order to manufacture the vibration type gyro sensor element 10 shown as the embodiment of the present invention, the resist film pattern is used for the front surface and the back surface of the single crystal silicon substrate 1, and the respective surfaces are used. Several processing steps are required. Specifically, anisotropic etching is performed using the resist film pattern 3 on the back surface side of the single crystal silicon substrate 1 on which the thermal oxide film 2B is formed, and on the surface side on which the thermal oxide film 2A is formed. On the other hand, using the resist film pattern, the reference electrode 4a, the piezoelectric body 5, the drive electrode 6a, the detection electrodes 6b and 6c are formed, and the reactive etching for forming the surrounding space 12 is performed.

  When these resist film patterns are formed on the front and back surfaces of the single crystal silicon substrate 1, an expensive apparatus such as the above-described double-side aligner or alignment apparatus is used in order to prevent the resist film patterns formed on both sides from shifting. It was necessary.

  When the vibration type gyro sensor element 10 is manufactured at the prototype stage, as described above, the rectangular single crystal silicon substrate 1 of 3 cm × 3 cm is used, and the end of the substrate is used as a reference. It is possible to align the resist film pattern on both sides without using a simple apparatus. However, even when such a rectangular single crystal silicon substrate 1 is used, there is a very high possibility that a resist film pattern formed on the front surface and the back surface will be shifted due to an error generated when cutting into a rectangular shape.

  For mass production, a circular silicon wafer obtained by slicing a silicon ingot is used as a single crystal silicon substrate, and a manufacturing line corresponding to a circular single crystal silicon substrate that has already been constructed and operated is used. This is the most efficient in terms of cost and manufacturing time.

  Therefore, when the single crystal silicon substrate 1 cut into a rectangular shape is used in a mass production process, various problems such as a review of the production line and an increase in cost due to an increase in the process for cutting into a rectangular shape arise.

  Therefore, when manufacturing the vibration-type gyro sensor element 10 shown as the embodiment of the present invention, it is positioned as the single crystal silicon substrate 1 in the step of forming a resist film pattern on the front surface and the back surface of the single crystal silicon substrate 1. Even when a circular single crystal silicon substrate for which it is difficult to provide a reference for alignment is used, a resist film pattern to be accurately formed on the front surface and the back surface without using an expensive device such as the above-described double-side aligner device. The method of alignment is shown below.

  41 is a plan view showing a state of the single crystal silicon substrate 51 having the thermal oxide film formed on the front surface and the back surface, and FIG. 42 is parallel to the orientation flat surface 53 of the single crystal silicon substrate 51 shown in FIG. It is sectional drawing at the time of cut | disconnecting with a XX line. A single crystal silicon substrate 51 shown in FIG. 41 has a diameter of 4 inches and a thickness of 0.3 mm, and is cut out so that the surface orientation of the front surface and the back surface is {100}. In addition, the orientation of the orientation flat surface (hereinafter referred to as the orientation flat surface) 53 shown in FIGS. 41 and 42 is {110}.

The front and back surfaces of the single crystal silicon substrate 51 are thermally oxidized to form thermal oxide films 52A and 52B, which are SiO ₂ films, respectively. The thermal oxide films 52A and 52B formed on the front and back surfaces of the single crystal silicon substrate 51 are each 100 nm.

  As described above, the single crystal silicon substrate 51 differs from the single crystal silicon substrate 1 used in manufacturing the vibration-type gyro sensor element 10 only in size and shape, and has a cut plane orientation. The vibration type gyro sensor element 10 can be similarly manufactured using the manufacturing method described above.

  At this time, as a reference for aligning the resist film pattern formed on the front surface and the back surface of the single crystal silicon substrate 51, a hole is formed so as to penetrate the single crystal silicon substrate 51, and the alignment reference Make it a landmark. The hole penetrating through the single crystal silicon substrate 51 is naturally at the same position when viewed from the thermal oxide film 52A side which is the front surface of the single crystal silicon substrate 51 and when viewed from the thermal oxide film 52B side which is the back surface. Therefore, the shift can be completely eliminated by forming the resist film pattern on the front and back surfaces with reference to the holes.

  Since the through hole penetrating the single crystal silicon substrate 51 is formed by crystal anisotropic etching, it is performed simultaneously with the step of forming the diaphragm by performing crystal anisotropic etching with the resist film pattern 3 described above.

  43 is a plan view showing a state of a single crystal silicon substrate 51 in which a resist film pattern 54 having openings 54a and 54b is formed on a thermal oxide film 52A. FIG. 44 is a single crystal shown in FIG. FIG. 6 is a cross-sectional view of the silicon substrate 51 taken along the XX line parallel to the orientation flat surface 53.

  The openings 54a and 54b of the resist film pattern 54 are formed in a square shape having a side of 150 μm and parallel to the orientation flat surface 53 having at least one side being a {110} plane. The resist film pattern 54 is the same as the resist film pattern 3 shown in FIG. 7 described above, and a plurality of openings for forming the vibration type gyro sensor element 10 are also formed although not shown. Accordingly, the openings 54a and 54b need to be formed at positions that do not interfere when the vibration type gyro sensor element 10 is formed.

  At this time, positions where the plurality of openings for forming the vibration type gyro sensor element 10 are formed are determined with reference to the openings 54a and 54b.

  The shapes of the openings 54a and 54b are arbitrary, but in order to accurately match the resist film pattern formed on the front surface and the back surface, at least one side of the openings 54a and 54b is parallel to the {110} plane. It is desirable to do. Moreover, since the opening is a reference for determining a relative position on the front surface and the back surface, it is not always necessary to prepare two openings like the openings 54a and 54b, and at least one or more may be formed. .

  Next, the thermal oxide film 52A exposed by the openings 54a and 54b of the resist film pattern 54 is removed by etching. FIG. 45 is a plan view showing a state of the single crystal silicon substrate 51 from which the openings 52Aa and 52Ab are formed by removing the thermal oxide film 52A exposed by the openings 54a and 54b, and FIG. 2 is a cross-sectional view of the single crystal silicon substrate 51 shown in FIG. The thermal oxide film 52A is removed by an ammonium fluoride solution.

  Subsequently, an opening for performing crystalline anisotropic etching is provided on the thermal oxide film 52B side. 47 is a plan view showing a state of the single crystal silicon substrate 51 in which a resist film pattern 55 having openings 55a and 55b is formed on the thermal oxide film 52B. FIG. 48 is a plan view showing the single crystal shown in FIG. FIG. 6 is a cross-sectional view of the silicon substrate 51 taken along the XX line parallel to the orientation flat surface 53.

  The openings 55a and 55b of the resist film pattern 55 penetrate through holes formed by etching from the openings 52Aa and 52Ab formed on the thermal oxide film 52A described above when the single crystal silicon substrate 51 is etched. It is necessary to form in such a position.

  For example, as shown in FIGS. 47 and 48, the openings 55a and 55b of the resist film pattern 55 are made larger than the openings 54a and 54b of the resist film pattern 54 used to form the openings 52Aa and 52Ab. If the openings 52Aa and 52Ab are accommodated in the openings 55a and 55b, the area on the side of the thermal oxide film 52B etched by the crystal anisotropic etching increases, so that a through hole can be formed reliably. .

  Therefore, as long as the openings 55a and 55b of the resist film pattern 55 satisfy the above conditions, the shape and the formation position are arbitrary. Also, it is desirable that the openings 55a and 55b of the resist film pattern 55 have at least one side parallel to the {110} plane, like the openings 54a and 54b of the resist film pattern 54.

  Next, the thermal oxide film 52B exposed by the openings 55a and 55b of the resist film pattern 55 is removed by etching. 49 is a plan view showing a state of the single crystal silicon substrate 51 from which the openings 52Ba and 52Bb are formed by removing the thermal oxide film 52B exposed by the openings 55a and 55b, and FIG. 2 is a cross-sectional view of the single crystal silicon substrate 51 shown in FIG. The thermal oxide film 52B is removed with an ammonium fluoride solution.

  Subsequently, a portion of the thermal oxide film 52A and the thermal oxide film 52B are removed, and the anisotropic crystal is different from the single crystal silicon substrate 52 in which the {100} plane is exposed in the size of the openings 52Aa, 52Ab, 52Ba, and 52Bb. Etching is performed until the through hole is formed.

  51 is a plan view showing a state of the single crystal silicon substrate 51 in which the through holes 51a and 51b are formed by crystal anisotropic etching. FIG. 52 shows the orientation flat surface 53 of the single crystal silicon substrate 51 shown in FIG. It is sectional drawing at the time of cut | disconnecting by XX line | wire parallel to A.

  Etching solutions that can be used when crystal anisotropic etching is performed on single crystal silicon include TMAH (tetramethylammonium hydroxide), KOH (potassium hydroxide), EDP (ethylenediamine-pyrocatechol-water), humanradine, etc. It is.

  Thus, with reference to the formed through holes 51a and 51b, the reference electrode 4a, the drive electrode 6a, and the detection electrode of the vibration type gyro sensor element 10 are formed on the thermal oxide film 52A side that is the surface of the single crystal silicon substrate 51. 6b, 6c, and further, by aligning the resist film pattern when forming the flattening resist film 7 and the wiring connection terminals A, B, C, D, it was formed on the thermal oxide film 52B side which is the back surface. It can be accurately aligned with the resist film pattern. That is, the deviation between the root line R of the vibrator 11 and the boundary line K of the vibration type gyro sensor element 10 described with reference to FIGS. 35A and 35B can be avoided without using an expensive double-side aligner device. Can be suppressed.

  When the vibration type gyro sensor element 10 is formed using this method, the deviation between the root line R of the vibrator 11 and the boundary line K is, for example, the vertical resonance frequency and the horizontal resonance frequency described in FIG. A gyro sensor having a very high sensitivity can be manufactured within a range of substantially within ± 30 μm, that is, within a difference of 30 μm.

  As described above, the single crystal silicon substrate 1 is subjected to crystal anisotropic etching and reactive ion etching to form a cantilever vibrator 11 that is a quadrangular prism having a rectangular cross section. Thus, the vibration type gyro sensor 10 capable of detecting the angular velocity in one direction applied to the longitudinal direction of the eleventh can be manufactured.

  Further, using the above-described method for manufacturing the vibration type gyro sensor 10, the vibration type gyro sensor element that simultaneously detects angular velocities in two directions provided so that the vibrator 61 and the vibrator 62 are orthogonal to each other as shown in FIG. 60 can also be formed.

  The manufacturing process of the vibration-type gyro sensor element 60 is exactly the same as the manufacturing process of the vibration-type gyro sensor element 10, but the size of the opening at the time of anisotropic anisotropic etching, that is, the size of the diaphragm formed after the etching is shown in FIG. As shown in t61 and t62, even when the vibrators 61 and 62 are arranged orthogonally, the surrounding space 63 that enables vibration at a desired resonance frequency is formed without interfering with the vibration of the vibrators 61 and 62. The size should be possible.

  As described above, the biaxial vibrating gyro sensor element 60 manufactured by the same method as the vibrating gyro sensor element 10 has the same thickness of the vibrators 61 and 62 by crystal anisotropic etching. Thus, the shapes of the vibrators 61 and 62 can be made uniform, and the root lines R1 and R2 of the vibrators 61 and 62, which are the starting points of vibration formed by crystal anisotropic etching, are completely formed. Therefore, it is possible to detect angular velocities in two directions perpendicular to each other with very high accuracy.

  For example, when two vibration type gyro sensor elements are individually manufactured and the angular velocity sensor is constructed by arranging the vibrators in the orthogonal direction later, it is difficult to completely orthogonally detect them. Angular velocity is likely to contain errors.

  Therefore, a highly accurate biaxial angular velocity sensor can be constructed by using the vibration-type gyro sensor element 60 manufactured by the manufacturing method described above.

It is a perspective view for demonstrating the vibration type gyro sensor element shown as the best form for implementing this invention. It is a figure for demonstrating the structure of the angular velocity sensor provided with the vibration gyro sensor element. It is a perspective view for demonstrating the vibrator | oscillator with which the same vibration type gyro sensor element is provided. It is a top view for demonstrating the vibration type gyro sensor element. It is a top view for demonstrating the single crystal silicon substrate used when manufacturing the vibration type gyro sensor element. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate shown in FIG. 5 by XX line. It is a top view which shows a mode that the resist film pattern was formed in the single crystal silicon substrate. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate shown in FIG. 6 by XX line. It is a top view which shows a mode at the time of removing the thermal oxide film of a single crystal silicon substrate. FIG. 10 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 9 taken along the line XX. It is a top view which shows a mode that the crystal anisotropic etching was performed to the single crystal silicon substrate. It is sectional drawing at the time of cut | disconnecting by the single crystal silicon substrate XX line shown in FIG. It is sectional drawing which expanded and showed the area | region A shown in FIG. It is the top view which showed the mode of the surface side of a single crystal silicon substrate. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate shown in FIG. 14 with XX line. It is a top view which shows the mode of the single crystal silicon substrate in which the lower electrode film, the piezoelectric film, and the upper electrode film were formed. FIG. 17 is a cross-sectional view when the single crystal silicon substrate shown in FIG. 16 is cut along XX line. It is a top view which shows the mode of the single crystal silicon substrate in which the drive electrode and the detection electrode were formed. It is sectional drawing when the single crystal silicon substrate shown in FIG. 18 is cut | disconnected by XX line. It is a top view which shows the mode of the single crystal silicon substrate in which the piezoelectric material was formed. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate shown in FIG. 20 by XX line. It is a top view which shows the mode of the single crystal silicon substrate in which the reference electrode was formed. It is sectional drawing at the time of cut | disconnecting the single crystal silicon substrate shown in FIG. 22 by XX line. It is a top view which shows the mode of the single crystal silicon substrate in which the planarization resist film was formed. FIG. 25 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 24 taken along line YY. It is a top view which shows the mode of the single crystal silicon substrate in which the wiring connection terminal was formed. FIG. 27 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 26 taken along line YY. It is a top view which shows the mode of the single crystal silicon substrate in which surrounding space was formed in the circumference | surroundings of a vibrator | oscillator by reactive ion etching. FIG. 29 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 28 taken along line YY. FIG. 29 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 28 taken along line XX. It is a top view which shows the single crystal silicon substrate in which the some vibration type gyro sensor element was formed. It is a top view which shows the mode of the single crystal silicon substrate which showed the cutting line at the time of cut | disconnecting the several vibration type gyro sensor element formed in the single crystal silicon substrate. It is a top view which shows a mode when a vibration type gyro sensor element is affixed on an IC substrate. It is a top view which shows a mode when a cover material is attached to the angular velocity sensor provided with a vibration type gyro sensor element. (A) is the top view which showed the root line of the vibrator | oscillator of a vibration type gyro sensor element, (b) and (c) cut | disconnected the vibration type gyro sensor element shown to (a) by the YY line | wire, It is sectional drawing for demonstrating the shift | offset | difference of a root line and a boundary line. It is a perspective view of a vibration type gyro sensor element when the boundary line is shifted in the positive direction of the Y axis with respect to the root line of the vibrator. It is sectional drawing of a vibration type gyro sensor element when a boundary line has shifted in the minus direction of the Y axis with respect to the root line of the vibrator. It is the figure which showed the longitudinal resonant frequency of the vibrator | oscillator with respect to the deviation | shift amount of the root line of a vibrator | oscillator, and a boundary line, and a horizontal resonant frequency. FIG. 6 is a perspective view showing a case where a boundary line is shifted in the positive direction of the Y axis with respect to a base line of a vibrator in a vibration type gyro sensor element in which an inclined surface is not formed on a base. FIG. 5 is a perspective view showing a case where a boundary line is deviated in the negative direction of the Y axis with respect to a base line of a vibrator in a vibration type gyro sensor element in which an inclined surface is not formed on a base. It is a top view which showed the mode of the single crystal silicon substrate used in order to demonstrate the method of forming the through-hole used as the reference | standard at the time of forming a resist film pattern in the front and back of a single crystal silicon substrate. FIG. 42 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 41 taken along line XX. It is a top view which shows a mode at the time of forming a resist film pattern on the surface of a single crystal silicon substrate. FIG. 44 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 43 taken along line XX. It is a top view which shows a mode at the time of removing a part of thermal oxide film of the surface of a single crystal silicon substrate. FIG. 46 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 45 taken along line XX. It is a top view which shows the mode at the time of forming a resist film pattern in the back surface of a single crystal silicon substrate. FIG. 48 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 47 when cut by XX line. It is a top view which shows a mode when a part of thermal oxide film of the back surface of a single crystal silicon substrate is removed. FIG. 50 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 49 taken along line XX. It is a top view which shows a mode at the time of performing crystal anisotropic etching to the single crystal silicon substrate from which a part of the thermal oxide film has been removed. FIG. 52 is a cross-sectional view of the single crystal silicon substrate shown in FIG. 51 taken along the line XX. It is a top view for demonstrating the vibration type gyro sensor element which formed the vibrator | oscillator in two orthogonal directions.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,51 Single crystal silicon substrate, 4a Reference electrode, 5a Piezoelectric body, 6a Drive electrode, 6b, 6c Detection electrode, 10, 60, 100 Vibrating gyro sensor element, 11, 61, 62 Vibrator, 12, 63 Ambient space , R, R1, R2 Root line

Claims (18)

In a manufacturing method of a vibration type gyro sensor element including a cantilever-shaped vibrator having a lower electrode, a piezoelectric thin film, and an upper electrode, and detecting an angular velocity using a piezoelectric effect of the piezoelectric thin film,
On one main surface of the single crystal silicon substrate whose one main surface and the other main surface have a {100} plane orientation, a first opening formed by a straight line parallel or perpendicular to the {110} plane is provided. Forming a first protective film pattern, performing crystal anisotropic etching to the thickness of the vibrator with respect to the first opening,
The lower electrode, the piezoelectric thin film, and the upper electrode are sequentially stacked in the region to be the vibrator on the other main surface opposite to the one main surface that has been crystal anisotropically etched until the thickness of the vibrator is reached. Formed,
The other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed is configured by a straight line parallel or perpendicular to the {110} plane, and the vibrator has the cantilever shape. By forming a second protective film pattern having a second opening formed with a void, and performing reactive ion etching (RIE) on the second opening, the vibrator A manufacturing method of a vibration type gyro sensor element characterized by comprising:
However, “{}” is a symbol for collectively representing equivalent plane orientations having different directions. A drive electrode formed in the longitudinal direction of the vibrator for applying a voltage for vibrating the vibrator to the upper electrode;
2. The vibration according to claim 1, comprising a pair of detection electrodes formed in parallel with each other in the longitudinal direction of the vibrator without being in contact with the drive electrode, with the drive electrode interposed therebetween. Type gyro sensor element manufacturing method. Forming a third protective film pattern having at least one or more third openings on the one main surface of the single crystal silicon substrate;
A fourth opening is disposed on the other main surface of the single crystal silicon substrate at a position facing the third opening of the third protective film pattern formed on the one main surface. Forming the fourth protective film pattern, and performing crystal anisotropic etching on the third opening and the fourth opening,
Forming a through hole used as a positioning reference when forming a protective film pattern on the one main surface and the other main surface;
The method for manufacturing a vibration type gyro sensor element according to claim 1. Forming the third opening of the third protective film pattern in the first protective film pattern having the first opening;
4. The vibrating gyro sensor element according to claim 3, wherein crystal anisotropic etching is performed on the third opening and the fourth opening during crystal anisotropic etching on the first opening. 5. Production method. In a vibration type gyro sensor element that includes a cantilever-shaped vibrator having a lower electrode, a piezoelectric thin film, and an upper electrode, and detects an angular velocity using the piezoelectric effect of the piezoelectric thin film,
On one main surface of the single crystal silicon substrate whose one main surface and the other main surface have a {100} plane orientation, a first opening formed by a straight line parallel or perpendicular to the {110} plane is provided. Forming a first protective film pattern, performing crystal anisotropic etching to the thickness of the vibrator with respect to the first opening,
The lower electrode, the piezoelectric thin film, and the upper electrode are sequentially stacked in the region to be the vibrator on the other main surface opposite to the one main surface that has been crystal anisotropically etched until the thickness of the vibrator is reached. Formed,
The other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed is configured by a straight line parallel or perpendicular to the {110} plane, and the vibrator has the cantilever shape. Formed by forming a second protective film pattern having a second opening having a void and performing reactive ion etching (RIE) on the second opening. A vibratory gyrosensor element comprising the vibrator.
However, “{}” is a symbol for collectively representing equivalent plane orientations having different directions. The upper electrode includes a drive electrode formed in a longitudinal direction of the vibrator for applying a voltage for vibrating the vibrator;
6. The drive electrode is formed so as to be sandwiched between a pair of detection electrodes formed in the longitudinal direction of the vibrator in parallel without contacting the drive electrode. Vibration gyro sensor element. The vibration type gyro sensor element according to claim 5, wherein a cross-sectional shape of the vibrator is a right-angled quadrilateral. The fixed end for fixing the cantilever-shaped vibrator is a {111} plane that forms an angle of 55 degrees with respect to the {100} plane of the other main surface formed by the crystal anisotropic etching. The vibration type gyro sensor element according to claim 5, wherein: The fixed end portion for fixing the cantilever-shaped vibrator having the {111} plane, which is formed by crystal anisotropic etching using the first protective film pattern; The border of
9. The vibration type according to claim 8, wherein a difference from the root line of the vibrator in the cantilever shape defined by reactive ion etching using the second protective film pattern is 30 μm or less. Gyro sensor element. Manufacture of a vibration type gyro sensor element that includes two orthogonal cantilever-shaped vibrators having a lower electrode, a piezoelectric thin film, and an upper electrode, and detects angular velocity in two orthogonal directions using the piezoelectric effect of the piezoelectric thin film In the method
On one main surface of the single crystal silicon substrate whose one main surface and the other main surface have a {100} plane orientation, a first opening formed by a straight line parallel or perpendicular to the {110} plane is provided. Forming a first protective film pattern, performing crystal anisotropic etching to the thickness of the vibrator with respect to the first opening,
The lower electrode, the piezoelectric thin film, and the region on the two main surfaces opposite to the one main surface that have been crystal-anisotropically etched until the thickness of the vibrator is reached. The upper electrode is formed by stacking in order,
On the other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed, two cantilevers that are composed of straight lines parallel or perpendicular to the {110} plane and perpendicular to the vibrator By forming a second protective film pattern having a second opening shaped as a beam-shaped gap and performing reactive ion etching (RIE) on the second opening. A method for manufacturing a vibration-type gyro sensor element, characterized in that two orthogonal vibrators are formed.
However, “{}” is a symbol for collectively representing equivalent plane orientations having different directions. A drive electrode formed in the longitudinal direction of the vibrator for applying a voltage for vibrating the vibrator to the upper electrode;
11. The vibration according to claim 10, comprising a pair of detection electrodes formed in parallel with each other in the longitudinal direction of the vibrator without being in contact with the drive electrode, with the drive electrode interposed therebetween. Type gyro sensor element manufacturing method. Forming a third protective film pattern having at least one or more third openings on the one main surface of the single crystal silicon substrate;
A fourth opening is disposed on the other main surface of the single crystal silicon substrate at a position facing the third opening of the third protective film pattern formed on the one main surface. Forming the fourth protective film pattern, and performing crystal anisotropic etching on the third opening and the fourth opening,
Forming a through hole used as a positioning reference when forming a protective film pattern on the one main surface and the other main surface;
The method for manufacturing a vibration type gyro sensor element according to claim 10. Forming the third opening of the third protective film pattern in the first protective film pattern having the first opening;
13. The vibrating gyro sensor element according to claim 12, wherein crystal anisotropic etching is performed on the third opening and the fourth opening at the time of crystal anisotropic etching on the first opening. Production method. In a vibration-type gyro sensor element that includes two orthogonal cantilever-shaped vibrators having a lower electrode, a piezoelectric thin film, and an upper electrode, and detects angular velocity in two orthogonal directions using the piezoelectric effect of the piezoelectric thin film,
On one main surface of the single crystal silicon substrate whose one main surface and the other main surface have a {100} plane orientation, a first opening formed by a straight line parallel or perpendicular to the {110} plane is provided. Forming a first protective film pattern, performing crystal anisotropic etching to the thickness of the vibrator with respect to the first opening,
The lower electrode, the piezoelectric thin film, and the region on the two main surfaces opposite to the one main surface that have been crystal-anisotropically etched until the thickness of the vibrator is reached. The upper electrode is formed by stacking in order,
On the other main surface on which the lower electrode, the piezoelectric thin film, and the upper electrode are formed, two cantilevers that are composed of straight lines parallel or perpendicular to the {110} plane and perpendicular to the vibrator By forming a second protective film pattern having a second opening shaped as a beam-shaped gap and performing reactive ion etching (RIE) on the second opening. A vibration type gyro sensor element comprising two orthogonally formed vibrators.
However, “{}” is a symbol for collectively representing equivalent plane orientations having different directions. The upper electrode includes a drive electrode formed in a longitudinal direction of the vibrator for applying a voltage for vibrating the vibrator;
15. A pair of detection electrodes formed in the longitudinal direction of the vibrator in parallel without contacting the drive electrode so as to sandwich the drive electrode. Vibration gyro sensor element. The vibratory gyro sensor element according to claim 14, wherein a cross-sectional shape of the vibrator is a right-angled quadrilateral. The fixed end for fixing the cantilever-shaped vibrator is a {111} plane that forms an angle of 55 degrees with respect to the {100} plane of the other main surface formed by the crystal anisotropic etching. The vibration type gyro sensor element according to claim 14, comprising: The fixed end portion for fixing the cantilever-shaped vibrator having the {111} plane, which is formed by crystal anisotropic etching using the first protective film pattern; The border of
18. The vibration type according to claim 17, wherein a difference from a root line of the vibrator having the cantilever shape defined by reactive ion etching using the second protective film pattern is 30 μm or less. Gyro sensor element.

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