JP2010155299A - Mems sensor and manufacturing method of mems sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniform the thickness of a flexible part of an MEMS sensor. <P>SOLUTION: The MEMS sensor has a laminated structure in which a support part, a spindle part, and a flexible part for connecting the support part to the spindle part to be deformed in accordance with a movement of the spindle part, are formed. The laminated structure includes: a single crystal silicon layer 10 forming the flexible part and having a flat lower surface; and a CMP stopper layer 30 laminated on the single crystal silicon layer and different from the single crystal silicon layer. A lower surface of the stopper layer and a lower surface of the single crystal silicon layer are included in the same plane, or the lower surface of the stopper layer is protruded from the single crystal silicon layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a MEMS (Micro Electro Mechanical Systems) sensor and a method for manufacturing the MEMS sensor.

Conventionally, a MEMS sensor having a flexible portion such as an acceleration sensor or a vibration gyroscope is known (see, for example, Patent Documents 1 and 2). In such a MEMS sensor, it is necessary to increase the dimensional accuracy of the thickness of the flexible portion in order to suppress variation in characteristics.
Japanese National Patent Publication No. 10-506717 Japanese translation of PCT publication No. 2002-500961

  However, when adjusting the thickness of the flexible portion by retreating the surface of the layer to be the flexible portion by CMP (Chemical Mechanical Polishing), it is not easy to control the end point of CMP to the target thickness.

  The present invention has been created to solve this problem, and an object thereof is to make the thickness of the flexible portion of the MEMS sensor uniform.

  (1) A MEMS sensor for achieving the above object includes a support part, a weight part, and a flexible part that connects the support part and the weight part and deforms as the weight part moves. The laminated structure includes a single crystal silicon layer that forms the flexible portion and has a flat bottom surface, and is laminated on the single crystal silicon layer and is different from the single crystal silicon layer. And the lower surface of the stopper layer and the lower surface of the single crystal silicon layer are included in the same plane, or the lower surface of the stopper layer protrudes from the lower surface of the single crystal silicon layer.

  According to the present invention, the stopper layer different from the single crystal silicon layer is laminated on the single crystal silicon layer constituting the flexible portion. Here, the term “heterogeneity” refers to the property that when the surface layer is removed at least by etching or CMP, the removal rate is low with respect to other layers, and the other layers can be selectively removed. If the bottom surface of the stopper layer, which is different from the single crystal silicon layer, and the bottom surface of the single crystal silicon layer are included in the same plane, or if the bottom surface of the stopper layer slightly protrudes from the bottom surface of the single crystal silicon layer, Thus, the thickness of the single crystal silicon layer can be adjusted. First, a recess having a predetermined depth is formed on the upper surface of the single crystal silicon wafer by etching. Then, a stopper layer different from the single crystal silicon wafer is stacked in the recess. Further, when the lower surface of the single crystal silicon wafer is retracted until at least the stopper layer is exposed, the thickness of the flexible portion can be adjusted. The depth of the recess in which the stopper layer is laminated can be accurately adjusted by etching. When the single crystal silicon wafer is retracted from the lower surface, the end point can be controlled based on the time when the stopper layer is exposed. If the back surface retreating process is terminated when the stopper layer is exposed, the thickness of the single crystal silicon layer is adjusted so that the lower surface of the stopper layer and the lower surface of the single crystal silicon layer are included in the same plane. If the lower surface receding process is terminated after a lapse of a predetermined time from the time when the stopper layer is exposed, the lower surface of the stopper layer protrudes from the lower surface of the single crystal silicon layer. That is, the MEMS sensor having the configuration of the present invention can accurately adjust the thickness of the flexible portion, so that the thickness of the flexible portion can be made uniform. When the lower surface of the single crystal silicon layer is further retracted from the time when the stopper layer is exposed, the lower surface of the single crystal silicon layer is further increased from the time when the stopper layer is exposed within a range in which the thickness of the single crystal silicon layer can be adjusted within a tolerance range. What is necessary is just to set the time which reverse | retreats short. In this specification, the upper and lower surfaces related to a certain layer are described with the interface corresponding to the other layer laminated with that layer as the base and the interface corresponding to the back of the top as the bottom.

(2) In the MEMS sensor for achieving the above object, the stopper layer may be in a region that is not deformed with the movement of the weight portion.
According to the present invention, the material of the stopper layer can be selected regardless of mechanical properties such as elastic modulus required for the flexible portion.

(3) In the MEMS sensor for achieving the above object, the MEMS sensor further includes a package to which the support portion is bonded via an adhesive layer, and a lower surface of the stopper layer is a surface bonded to the package of the support portion. The single crystal silicon layer may protrude from the lower surface.
According to the present invention, the portion of the stopper layer that slightly protrudes from the lower surface of the single crystal silicon layer functions as a spacer when bonding the support portion and the package. Therefore, according to the present invention, it is possible to realize a MEMS sensor in which the thickness of the adhesive layer that joins the support portion and the package is uniform.

(4) In the MEMS sensor for achieving the above object, the stopper layer may constitute a conductive through electrode.
By providing the stopper layer with the function of the through electrode, the MEMS sensor can be miniaturized.
(5) In the MEMS sensor for achieving the above object, a sidewall may be formed between the single crystal silicon layer and the stopper layer.
According to the present invention, generation of voids in the stopper layer can be prevented.

  (6) A MEMS sensor manufacturing method for achieving the above object includes a support part, a weight part, a flexible part that connects the support part and the weight part and deforms as the weight part moves. A method of manufacturing a MEMS including a laminated structure in which a recess having a predetermined depth is formed by etching on an upper surface of a single crystal silicon wafer serving as the flexible portion, and the recess is formed in the recess. The method includes stacking a stopper layer that is different from a single crystal silicon wafer and adjusting the thickness of the flexible portion by retracting at least the lower surface of the single crystal silicon wafer until the stopper layer is exposed.

  According to the present invention, when the single crystal silicon wafer serving as the flexible portion is retracted from the lower surface, the end point can be controlled with reference to the time when the stopper layer is exposed. Therefore, according to the present invention, a MEMS sensor with a uniform thickness of the flexible portion can be manufactured.

(7) In the MEMS sensor manufacturing method for achieving the above object, the concave portion may be formed in a region of the upper surface of the single crystal silicon wafer that is not deformed with the movement of the weight portion.
According to the present invention, the material of the stopper layer can be selected regardless of mechanical properties such as elastic modulus required for the flexible portion.

(8) In the MEMS sensor manufacturing method for achieving the above object, the side surface of the flexible portion may be exposed by removing the stopper layer by etching.
In the present invention, the stopper layer may be left in a completed state or may be completely removed before completion.
(9) In the MEM sensor manufacturing method for achieving the above object, a sidewall may be formed in the recess, and the stopper layer may be formed after the sidewall is formed. .
According to the present invention, generation of voids in the stopper layer can be prevented.

  (10) A MEMS sensor manufacturing method for achieving the above object includes a support portion, a weight portion, a flexible portion that connects the support portion and the weight portion and deforms as the weight portion moves. A method for manufacturing a MEMS sensor including a laminated structure in which an epitaxial crystal layer serving as the flexible portion is grown on a flat upper surface of a single crystal silicon wafer, and through holes are formed in the epitaxial crystal layer Forming a stopper layer different from the single crystal silicon wafer on the surface of the single crystal silicon wafer exposed in the through-hole, and retreating the lower surface of the single crystal silicon wafer until the stopper layer is exposed. The thickness of the flexible part is adjusted.

  In the present invention, it is difficult to increase the accuracy of the end point if the epitaxial crystal layer itself that becomes the flexible portion is used as a stopper when the lower surface of the single crystal silicon wafer is retracted. Therefore, a stopper layer which is different from the single crystal silicon wafer used as the base of the epitaxial crystal layer is laminated on the upper surface of the single crystal silicon wafer in the through hole formed in the epitaxial crystal layer. Then, when the single crystal silicon wafer is retracted from the lower surface, the end point can be controlled based on the time when the stopper layer is exposed. Therefore, according to the present invention, a MEMS sensor with a uniform thickness of the flexible portion can be manufactured.

  The order of the operations described in the claims is not limited to the order of description as long as there is no technical obstruction factor, and may be executed at the same time, may be executed in the reverse order of the description order, or may be continuous. It does not have to be executed in order.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.
1. First embodiment (Configuration)
The acceleration sensor which is 1st embodiment of the MEMS sensor of this invention is shown in FIG. 1 and FIG. 1A and 1B are sectional views showing a sensor die 1A of the acceleration sensor, and are sectional views taken along lines AA and BB shown in FIG. 1C, respectively. FIG. 1C is a top view of the sensor die 1A. FIG. 2 is a cross-sectional view showing the acceleration sensor 1. In FIG. 1A, FIG. 1B, and FIG. 2, the interface of the layer which comprises the sensor die 1A is shown with the broken line, and the boundary of the functional element which comprises the sensor die 1A is shown with the continuous line. In FIG. 1C, the sensor die 1A is shown in a state where the weight layer 60 is seen through.

  The acceleration sensor 1 is a MEMS sensor for detecting three-axis acceleration components orthogonal to each other. The acceleration sensor 1 includes a package 1B shown in FIG. 2 and a sensor die 1A housed in the package 1B.

The sensor die 1A is a laminated structure including a single crystal silicon layer 10, a first insulating layer 20, a stopper layer 30, a second insulating layer 40, a surface conducting wire layer 50, an adhesive layer 61, and a weight layer 60. It is. The thickness of the single crystal silicon layer 10 is 19.5 μm. The first insulating layer 20 and the second insulating layer 40 are made of a silicon oxide film (SiO ₂ ). The thicknesses of the first insulating layer 20 and the second insulating layer 40 are each 0.5 μm. The stopper layer 30 penetrates the single crystal silicon layer 10 and the first insulating layer 20. The stopper layer 30 is made of a silicon nitride film (Si _x N _y ). The surface conducting wire layer 50 is made of aluminum (Al). The thickness of the surface conducting wire layer 50 is 0.3 μm. The adhesive layer 61 is made of photosensitive polyimide. The thickness of the adhesive layer 61 is 10 μm. The weight layer 60 is made of glass. The thickness of the weight layer 60 is 400 μm.

  The sensor die 1 </ b> A of the acceleration sensor 1 is coupled to a frame-shaped support portion S, a cross-shaped flexible portion F in which four ends are coupled to the inside of the support portion S, and a central portion of the flexible portion F. And a piezoresistive element 131 as detection means provided in the flexible part F.

  The support portion S has a rectangular frame shape as shown in FIG. 1C. The support portion S includes a single crystal silicon layer 10, a first insulating layer 20, a stopper layer 30, and a second insulating layer 40. Since the lower surface of the support portion S is fixed to the package 1B, the support portion S substantially behaves as a rigid body. In the support portion S, the stopper layer 30 penetrates the single crystal silicon layer 10 and the first insulating layer 20.

  The cross-shaped flexible portion F has a form in which two beams fixed at both ends are coupled to each other at the center. The upper surface and the lower surface of the flexible part F are flat. Therefore, the thickness of the flexible part F is constant. The flexible portion F includes a single crystal silicon layer 10, a first insulating layer 20, a stopper layer 30, and a second insulating layer 40. A stopper layer 30 penetrates the single crystal silicon layer 10 and the first insulating layer 20 in the central portion of the flexible portion F. In the flexible portion F, the stopper layer 30 is in a region bonded to the weight portion M.

  The flexible part F behaves as a flexible film. The four ends of the flexible portion F are coupled to the four sides inside the support portion S. Since the support portion S behaves as a rigid body, the end of the flexible portion F is a fixed end in the coordinate system fixed to the acceleration sensor 1. Since the weight part M is coupled only to the flexible part F and floats from the bottom surface 90a of the package 1B as shown in FIG. 2, the flexible part F moves together with the weight part M in the coordinate system fixed to the acceleration sensor 1. To do. That is, the flexible portion F is deformed as the weight portion M moves. However, the region bonded to the weight portion M of the flexible portion F (the region overlapping the adhesive layer 61 in the stacking direction) does not deform with the movement of the weight portion M. Since the stopper layer 30 is located in a region where the flexible portion F is bonded to the weight portion M, mechanical properties such as the elastic modulus and toughness of the stopper layer 30 are substantially equal to the mechanical characteristics of the flexible portion F. Does not affect.

  The thickness of the flexible portion F is the sum of the thickness of the single crystal silicon layer 10, the thickness of the first insulating layer 20, and the thickness of the second insulating layer 40. A through hole filled with a stopper layer 30 is formed in the single crystal silicon layer 10 and the first insulating layer 20. The upper surface of the stopper layer 30, that is, the interface between the stopper layer 30 and the first insulating layer 20 is flat and continuous with the upper surface of the first insulating layer 20, that is, the interface between the first insulating layer 20 and the second insulating layer 40. The lower surface of the stopper layer 30 is flat and continuous with the lower surface of the single crystal silicon layer 10. Accordingly, the total thickness of the single crystal silicon layer 10 and the first insulating layer 20 is equal to the thickness of the stopper layer 30 penetrating them. This is the result of determining the end point of CMP at the time when the stopper layer 30 is exposed in the step of adjusting the thickness of the flexible portion F by CMP (Chemical Mechanical Polishing).

  That is, the stopper layer 30 is used for end point control for accurately adjusting the thickness of the single crystal silicon layer 10 constituting the flexible portion F by CMP, as will be described later. Therefore, the stopper layer 30 needs to be different from the single crystal silicon layer 10. Specifically, when the lower surface of the single crystal silicon layer 10 is retracted, there is a difference between when only the single crystal silicon 10 is processed and when the single crystal silicon layer 10 and the stopper layer 30 are processed simultaneously. It is necessary for this reaction to occur. The heterogeneous reaction here means, for example, that the machining surface retract speed decreases, the polishing head rotational torque changes, or the reflected light of the machining surface that gradually moves back changes under constant processing conditions. Or the spectrum of the transmitted light or reflected light of the liquid or gas reacting with the processed surface is changed. Further, for example, if a material having a sufficiently small selection ratio with respect to single crystal silicon is used for the stopper layer 30, the receding speed of the lower surface of the single crystal silicon layer 10 by CMP decreases when the stopper layer 30 is exposed. Even if the end point is controlled only by the time without detecting the heterogeneous reaction that occurs, the thickness of the single crystal silicon layer 10 can be accurately adjusted as compared with the case where the stopper layer 30 is not used. In short, regardless of whether or not a foreign reaction is detected, when the lower surface of the single crystal silicon layer 10 is retracted, a substance that causes a different reaction from when only the single crystal silicon 10 is processed is stopped. What is necessary is just to select as a material of the layer 30. FIG. An appropriate material to be selected must be selected depending on whether the lower surface of the single crystal silicon layer 10 is retracted by CMP, etching, polishing, or grinding, or what kind of slurry or processing liquid is used in CMP.

  For the purpose of adjusting the thickness of the single crystal silicon layer 10, the through hole filled with the stopper layer 30 may be formed in any part of the single crystal silicon layer 10, and any pattern may be used. However, when the stopper layer 30 is disposed in a region that is deformed with the movement of the weight portion M, the mechanical properties of the stopper layer 30 affect the mechanical properties of the flexible portion F. Therefore, it is preferable to dispose the stopper layer 30 in a region that does not deform with the movement of the weight portion M. Even if the stopper layer 30 is disposed in a region that does not deform with the movement of the weight portion M, it is preferable to reduce the pattern of the stopper layer 30 in order to reduce thermal stress. Moreover, in this embodiment, although the stopper layer 30 is arrange | positioned in both the flexible part F and the support part S, you may arrange | position only in any one.

  As shown in FIG. 1C, the weight portion M has a plate shape whose outer periphery is rectangular. Since the weight portion M is composed of the thick weight layer 60, it behaves substantially as a rigid body. A gap G is formed between the upper surface of the weight part M and the upper surface of the flexible part F. The diameter of the beads mixed in the adhesive layer 61 is set according to the height of the gap G (the distance between the upper surface of the weight part M and the upper surface of the flexible part F).

The piezoresistive element 131 is a detecting means for detecting the deformation of the flexible portion F accompanying the movement of the weight portion M. The piezoresistive element 131 includes a high resistance portion 131a and a low resistance portion 131b formed in the single crystal silicon layer 10. Boron (B) ions are diffused in the high resistance portion 131a at a concentration of 2 × 10 ¹⁸ / cm ³ . Boron ions are diffused in the low resistance portion 131b at a concentration of 2 × 10 ²⁰ / cm ³ . The low resistance portion 131b having a smaller specific resistance than the high resistance portion 131a reduces the connection resistance between the high resistance portion 131a and the surface conducting wire layer 50. The piezoresistive element 131 is connected to the surface conductor layer 50 through a contact hole formed in the first insulating layer 20 and the second insulating layer 40. The piezoresistive elements 131 are connected so as to form a total of three Wheatstone bridges, one set of four linearly arranged elements. A signal corresponding to each of the three-axis acceleration components orthogonal to each other can be obtained from each Wheatstone bridge.

  A package 1 </ b> B shown in FIG. 2 includes a lidless box-type base 90 and a cover 94 that closes the internal space of the base 90. The base 90 and the cover 94 are joined via an adhesive layer 93. The base 90 is provided with a plurality of through electrodes 91. One end of the wire 95 is bonded to the surface conductive layer 50 of the sensor die 1A, and the other end is bonded to the through electrode 91 of the package 1B. The lower surface of the support portion S constituted by the lower surface of the single crystal silicon layer 10 of the sensor die 1 </ b> A is bonded to the bottom surface 90 a inside the base 90 by an adhesive layer 92. The height of the gap between the flexible portion F of the sensor die 1A and the bottom surface 90a inside the base 90 is set according to the depth of the recess formed in the bottom surface 90a and the thickness of the adhesive layer 92. Note that an LSI die connected to the sensor die 1A may be accommodated in the package 1B.

(Production method)
Hereinafter, a method for manufacturing the acceleration sensor 1 will be described with reference to FIGS. 3 to 17 are cross-sectional views corresponding to the line AA shown in FIG. 1C except for FIG. 13B. 13B is a cross-sectional view corresponding to the line BB shown in FIGS. 1C and 13C.

First, as shown in FIG. 3, the high resistance portion 131a is formed by introducing impurities into the surface layer of the single crystal silicon wafer 10 to be the single crystal silicon layer 10 using a protective film R1 made of photoresist. As impurities, boron (B) ions are implanted at a concentration of 2 × 10 ¹⁸ / cm ³ , for example. After ion implantation, activation by annealing is performed. The thickness of the single crystal silicon wafer 10 may be thicker than the final thickness of the single crystal silicon layer 10.

  Next, a first insulating layer 20 is formed on the surface of the single crystal silicon wafer 10 as shown in FIG. As the first insulating layer 20, a silicon dioxide film having a thickness of 0.5 μm is formed by, for example, thermal oxidation or CVD.

  Next, as shown in FIGS. 5A and 5B, a hole 20h penetrating the first insulating layer 20 is formed by etching using a protective film R2 made of a photoresist. The pattern of the holes 20 h corresponds to the completed pattern of the stopper layer 30. The first insulating layer 20 is anisotropically etched by, for example, reactive ion etching.

  Next, as shown in FIG. 6, in the region of the single crystal silicon layer 10 exposed from the hole 20h, a recess 10h having a depth equal to the thickness of the single crystal silicon layer 10 in a predetermined completed state is formed by etching. . As a result, the hole 20h extends in the depth direction. The single crystal silicon layer 10 is anisotropically etched by, for example, reactive ion etching. In the present embodiment, the depth of the recess 10h is set to 19.5 μm.

Next, a material different from that of the single crystal silicon layer 10 is deposited on the upper surface of the single crystal silicon layer 10 exposed from the hole 20h (that is, the bottom surface of the recess 10h) and the upper surface of the first insulating layer 20, as shown in FIG. Thus, the stopper layer 30 that completely fills the hole 20h and the recess 10h is formed. The stopper layer 30 is made of a material that can sufficiently reduce the CMP selection ratio relative to the single crystal silicon layer 10 (that is, a material that can select a polishing liquid or slurry that does not substantially remove the stopper layer 30 together with the single crystal silicon layer 10). As the stopper layer 30, a silicon nitride film having a thickness of 15 μm is formed by, for example, a CVD method. As the stopper layer 30, a nitride film such as aluminum nitride (Al _x N _y ) or titanium nitride (Ti _x N _y ) may be formed, or silicon oxide (SiO _x ) or aluminum oxide (Al _x O _y). ), Tantalum oxide (TaO _x ), titanium oxide (TiO _x ), or other oxide films, tungsten silicide (WSi _x ), molybdenum silicide (MoSi _x ), titanium silicide (TiSi _x ), or the like. A film of a silicide compound may be formed, or a film of a metal such as copper (Cu), nickel (Ni), platinum (Pt), or gold (Au) may be formed.

  Next, as shown in FIG. 8, a film R <b> 3 for etching back is formed on the surface of the stopper layer 30. As the material of the coating R3, a material that can make the etching selection ratio with the stopper layer 30 substantially 1 is selected. For example, a coating R3 having a flat surface is formed by applying and baking a photoresist, SOG (Spin On Glass), polyimide, or the like.

  Next, as shown in FIG. 9, the upper surface of the first insulating layer 20 and the upper surface of the stopper layer 30 are made flat and continuous. Specifically, under the condition that the etching selectivity between the coating R3 and the stopper layer 30 is approximately 1: 1, the surface layer of the stopper layer 30 is etched back together with the coating R3 until the first insulating layer 20 is exposed. As a result, the stopper layer 30 remains only inside the hole 20h and the recess 10h, and the upper surface of the stopper layer 30 and the upper surface of the first insulating layer 20 are continuously flat.

Next, the second insulating layer 40 is formed on the top surfaces of the first insulating layer 20 and the stopper layer 30. As the second insulating layer 40, a silicon dioxide (SiO ₂ ) film is formed by CVD, for example. A film such as PSG (Phospho Silicate Grass), BPSG (Boro-Phospho Silicate Grass), or silicon nitride (Si _x N _y ) may be formed as the second insulating layer 40. When the stopper layer 30 is made of an insulating film, the second insulating layer 40 is not necessary. Subsequently, as shown in FIG. 10, a contact hole H3 is formed in the first insulating layer 20 and the second insulating layer 40 using a protective film R4 made of a photoresist to expose the high resistance portion 131a. The contact hole H3 is formed by anisotropically etching the first insulating layer 20 and the second insulating layer 40 by reactive ion etching using, for example, CF ₄ + H ₂ or CHF ₃ gas. The contact hole H3 may be formed by wet etching using hydrofluoric acid (HF) or buffered hydrofluoric acid (BHF).

Next, as shown in FIG. 11, the low resistance portion 131b is formed by introducing impurities into the high resistance portion 131a exposed from the contact hole H3. As impurities, boron ions are implanted at a concentration of 2 × 10 ²⁰ / cm ³ , for example. After ion implantation, activation by annealing is performed.

Next, as shown in FIG. 12, a surface conducting wire layer 50 is formed on the surface of the second insulating layer 40, and the surface conducting wire layer 50 is etched using a protective film R5 made of a photoresist, thereby conducting conducting wires and bonding pads in a predetermined pattern. Is formed. As the surface conductive layer 50, an aluminum (Al) film having a thickness of 0.3 μm is formed by sputtering, for example. A copper or aluminum silicon (AlSi) film may be formed as the surface conducting wire layer 50. The pattern of the surface conductive layer 50 is formed by reactive ion etching using, for example, chlorine (Cl ₂ ) gas. The pattern of the surface conductor layer 50 may be formed by wet etching.

Next, as shown in FIG. 13A, FIG. 13B, and FIG. 13C, by etching the single crystal silicon layer 10, the first insulating layer 20, and the second insulating layer 40 using the protective film R6 made of photoresist, the flexible portion is obtained. An F pattern is formed. The pattern of the flexible part F is, for example, etching the first insulating layer 20 and the second insulating layer 40 by reactive ion etching using CHF ₃ gas, and subsequently reactive ions using CF ₄ gas and O ₂ gas. The single crystal silicon layer 10 is formed by etching. At this time, the depth of etching the single crystal silicon layer 10 may be deeper than the thickness of the completed state of the single crystal silicon layer 10. The pattern of the flexible portion F may be formed by wet etching using hydrofluoric acid or buffered hydrofluoric acid.

  Next, the weight layer 60 is processed as shown in FIG. That is, first, as shown in FIG. 14A, the pattern of the adhesive layer 61 is formed on the upper surface of the wafer 60 to be the weight layer 60. Specifically, a photosensitive polyimide having a thickness of 10 μm is applied on the upper surface of a 400 μm thick glass wafer, and patterned into a predetermined shape by exposure and development. Next, as shown in FIG. 14A and FIG. 14B, the side surface of the weight portion M is formed by forming a groove 60 h in the wafer 60. That is, the position of the side surface of the groove 60h is set so as to be the side surface of the weight portion M. Specifically, for example, half dicing for forming a groove 60h having a depth of 200 μm is performed by a dicer.

  Next, as shown in FIG. 15, the upper surface (surface on which the surface conductive layer 50 is formed) of the laminated structure including the single crystal silicon layer 10 and on which functional elements such as the flexible portion F and the piezoresistive element 131 are formed. ) And the surface of the wafer 60 on which the groove 60 h is formed are bonded together by an adhesive layer 61. For example, two workpieces are bonded via the adhesive layer 61 by applying a load of 2 tons per 6 inch wafer while heating at 250 ° C.

  Next, the lower surface of the weight layer 60 of the laminated structure W formed by the above-described steps is bonded to the sacrificial substrate 99 as shown in FIG. As the adhesive layer 98, for example, a wax, a photoresist, a double-sided pressure-sensitive adhesive sheet, or the like is used.

  Next, as shown in FIG. 17, the thickness of the single crystal silicon layer 10 is adjusted by sequentially retracting the lower surface of the single crystal silicon layer 10 by grinding, polishing, and CMP until the stopper layer 30 is exposed. At this time, a stopper layer 30 made of a material different from that of the single crystal silicon layer 10 can be used for CMP end point control. Specifically, since it is possible to adjust the thickness of the single crystal silicon layer 10 by stopping CMP when it is detected that the lower surface of the foreign stopper layer 30 is exposed from the single crystal silicon layer 10, the stopper layer The thickness of the single crystal silicon layer 10 can be accurately adjusted based on the depth at which 30 is embedded in the single crystal silicon layer 10. In the present embodiment, the thickness of the single crystal silicon layer 10 is adjusted to 19.5 μm, which is the depth of the recess 10 h formed in the step shown in FIG. The total thickness of the single crystal silicon layer 10, the first insulating layer 20, and the second insulating layer 40 whose thicknesses are adjusted in this step is the thickness of the flexible portion F.

  Next, as shown in FIG. 18, the wafer 60 is cut along the groove 60 h formed in the wafer 60. Specifically, full dicing is performed by cutting the wafer 60 along the groove 60h with a rotary blade of a dicer. As a result, the weight part M is released. Thereafter, the adhesive layer 98 is removed from the workpiece, and post-processes such as dicing and packaging on the single crystal silicon layer 10 side are performed, whereby the acceleration sensor 1 shown in FIGS. 1 and 2 is completed. Note that after the thickness of the single crystal silicon layer 10 is adjusted, the sacrificial substrate 99 may be removed and the laminated structure W may be temporarily bonded again to the dicing film.

  According to the method for manufacturing the acceleration sensor 1 described above, when the thickness of the single crystal silicon layer 10 to be the flexible portion F is adjusted by CMP, the stopper layer 30 made of a material different from that of the single crystal silicon layer 10 is used for end point control. Therefore, the thickness of the flexible part F can be adjusted accurately. For this reason, the thickness of the flexible part F can be made uniform. Therefore, the acceleration sensor 1 with small variation in characteristics can be manufactured.

2. Second embodiment (Configuration)
The acceleration sensor 2 which is 2nd embodiment of the MEMS sensor of this invention is shown in FIG. In FIG. 19, the interface of the layers constituting the sensor die 2A is indicated by a broken line, and the boundary of the functional elements constituting the sensor die 2A is indicated by a solid line. A sidewall 31 may be formed between the stopper layer 32 and the single crystal silicon layer 10 as shown in FIG. The sidewall 31 has a form that becomes thinner toward the upper surface of the first insulating layer 20. By adding the sidewalls 31, the generation of voids in the stopper layer 32 can be prevented. The lower surface of the stopper layer 32 filling the inside of the sidewall 31 is continuous with the lower surface of the single crystal silicon layer 10 in a flat manner. This is a result of adjusting the thickness of the single crystal silicon layer 10 based on the lower surface of the stopper layer 32. The lower surface of the stopper layer 32 is coupled to the weight layer 60. The upper surface of the stopper layer 32 is flat and continuous with the upper surface of the first insulating layer 20. The weight layer 60 constituting the weight part M of the sensor die 2A is made of a metal such as copper. The thickness of the weight layer 60 is 100 μm.

  The support portion S includes the weight layer 60, the single crystal silicon layer 10, and the first insulating layer 20. The sensor die 2 </ b> A is bonded to the package 1 </ b> B on the lower surface of the support portion S configured by the lower surface of the weight layer 60. For this reason, in the present embodiment, the weight portion M faces the bottom surface 90a of the package 1B.

(Production method)
After performing the process corresponding to FIG. 6 described in the first embodiment, the upper surface of the single crystal silicon layer 10 exposed from the hole 20h (that is, the recess 10h formed in the single crystal silicon layer 10) and the first insulating layer 20 is deposited on the upper surface of 20 to form the sidewall layer 31 shown in FIG. For example, a polycrystalline silicon film is formed as the sidewall layer 31 by the CVD method. Examples of the material of the sidewall layer 31 include semiconductors such as single crystal silicon and silicon germanium (SiGe), nitrides such as silicon nitride, aluminum nitride, and titanium nitride, and oxides such as aluminum oxide, tantalum oxide, titanium oxide, and silicon oxide. , Silicide compounds such as tungsten silicide (WSi _x ), molybdenum silicide (MoSi _x ), titanium silicide (TiSi _x ), tungsten (W), palladium (Pd), copper, nickel (Ni), platinum (Pt), silver ( A metal such as Au) may be used. The thickness of the sidewall layer 31 is, for example, 0.5 μm so as not to fill the hole 20h and the recess 10h. The upper surface of the sidewall layer 31 has a gentle curved surface near the edge of the hole 20h.

Next, as shown in FIG. 21, the first insulating layer 20 and the single crystal silicon layer 10 are exposed on the entire top surface of the sidewall layer 31, and the bottom of the recess 10h of the single crystal silicon layer 10 is etched to a predetermined depth. The side wall layer 31 is left only inside the holes 20h and the recesses 10h. The sidewall layer 31 remaining inside the hole 20 h and the recess 10 h becomes the sidewall 31. The sidewall layer 31 is anisotropically etched by reactive ion etching using, for example, CF ₄ gas. In this step, the etching depth of the single crystal silicon layer 10 is 0.3 μm.

  Next, as shown in FIG. 22, a stopper layer 32 is formed to cover the sidewall 31 and the first insulating layer 20, and the hole 20h and the recess 10h are completely filled. At this time, since the upper end of the sidewall 31 is a gentle curved surface without corners, the stopper layer 32 is less likely to be voided. Therefore, the manufacturing yield is improved. As the stopper layer 32, a silicon nitride film having a thickness of 10 μm is formed by, for example, a CVD method or a low pressure CVD method.

  Next, steps corresponding to FIGS. 8 and 9 described in the first embodiment are performed, and the surface layer of the stopper layer 32 is removed until the first insulating layer 20 is exposed as shown in FIG. As a result, the stopper layer 32 remains only inside the hole 20h and the recess 10h, and the upper surface of the stopper layer 32 and the upper surface of the first insulating layer 20 are continuously flat.

  Next, after forming the low resistance portion 131b, the surface conducting wire layer 50, and the flexible portion F in the same manner as in the first embodiment, the laminated structure W formed on the sacrificial substrate 99 by the above steps as shown in FIG. Is temporarily bonded.

  Next, as shown in FIG. 25, the thickness of the single crystal silicon layer 10 is adjusted by sequentially retracting the lower surface of the single crystal silicon layer 10 by grinding, polishing, and CMP until the stopper layer 32 is exposed. At this time, since the stopper layer 32 made of a material different from that of the single crystal silicon layer 10 can be used for the end point control of CMP, the stopper layer 32 is accurately determined based on the depth at which the single crystal silicon layer 10 is embedded. The thickness of the single crystal silicon layer 10 can be adjusted. In the present embodiment, since the second insulating layer 40 is omitted, the total thickness of the single crystal silicon layer 10 adjusted in this step and the thickness of the first insulating layer 20 is the thickness of the flexible portion F. It will be.

  Next, as shown in FIG. 26, protective films R7 and R8, which serve as a mold for forming the weight M, are formed. In order to form a gap G between the weight part M and the flexible part F, the protective film serving as a mold has a two-layer structure of R7 and R8. Specifically, for example, a negative photoresist is applied to the upper surface of the single crystal silicon layer 10, and exposed and developed to form a protective film R7 having the same thickness as the gap G (for example, 30 μm). Next, a negative photoresist is applied to the upper surfaces of the protective film R7 and the single crystal silicon layer 10, and exposed and developed to form a protective film R8 thicker than the weight portion M (for example, 100 μm or more).

Next, as shown in FIG. 27, the weight portion M is formed by forming the weight layer 60 by plating using the protective films R7 and R8 as a mold. For example, the weight layer 60 having a thickness of 100 μm is formed by electroless plating of copper (Cu). The weight layer 60 may be formed by forming a copper film having a thickness of 300 nm as a seed layer by sputtering and then growing the copper film by electrolytic plating. Further, after the weight layer 60 is formed by plating, the thickness of the weight layer 60 may be adjusted by either grinding, polishing, or CMP.
Then, when post-processes such as dicing and packaging are performed, the acceleration sensor 2 shown in FIG. 19 is completed.

3. Third Embodiment (Configuration)
The acceleration sensor 3 which is 3rd embodiment of the MEMS sensor of this invention is shown in FIG. In FIG. 28, the interfaces of the layers constituting the sensor die 3A are indicated by broken lines, and the boundaries of the functional elements constituting the sensor die 3A are indicated by solid lines. In the present embodiment, the lower surface of the stopper layer 32 protrudes from the lower surface of the single crystal silicon layer 10.

  As shown in FIG. 28C, since the lower surface of the stopper layer 32 protrudes from the lower surface of the single crystal silicon layer 10 in the flexible portion F, the flexible portion F and the bottom surface 90a inside the base 90 of the package 1B come into contact with each other. Sticking can be prevented. Further, since the lower surface of the stopper layer 32 protrudes from the lower surface of the support portion S, the thickness of the adhesive layer 92 that connects the support portion S and the base 90 of the package 1B can be made uniform. That is, since the stopper layer 32 functions as a spacer, the distance between the lower surface of the weight portion M and the bottom surface 90a inside the base 90 of the package 1B depends on the height at which the bottom surface of the stopper layer 32 protrudes from the bottom surface of the support portion S. It can be set accurately. For example, when the thickness of the adhesive layer 92 is set with beads mixed with the adhesive, the distribution density of the beads is not stable, and thus the thickness of the adhesive layer 92 is non-uniform. In this embodiment, the beads are used as spacers. Therefore, the thickness of the adhesive layer 92 can be made uniform. In the support portion S, the number of the lower surface of the stopper layer 32 protruding from the lower surface of the single crystal silicon layer 10 is preferably set to 3 or more.

  A third insulating layer 70 is formed between the weight layer 60 made of metal formed by plating and the surface conductor layer 50. The third insulating layer 70 is made of a silicon oxide film. The thickness of the third insulating layer 70 is 800 nm. As the third insulating layer 70, BSG, PSG, BPSG, a silicon nitride film, or the like may be used.

(Production method)
After performing the steps up to FIG. 23 described in the second embodiment, as shown in FIG. 29, a third insulating layer 70 is formed on the upper surfaces of the surface conductive layer 50 and the first insulating layer 20, and a protective film R9 is used. Then, the third insulating layer 70 is etched to expose the bonding pad region of the surface conductive layer 50.

  Next, as shown in FIG. 30, protective films R <b> 7 and R <b> 8 for forming the weight portion M are formed on the upper surfaces of the third insulating layer 70, the surface conductive layer 50 and the first insulating layer 20.

  Next, as shown in FIG. 31, the weight layer 60 is formed by plating using the protective films R7 and R8 as in the second embodiment.

  Next, as shown in FIG. 32, the laminated structure W formed by the above-described steps together with the protective films R7 and R8 is temporarily bonded to the sacrificial substrate 99. At this time, the lower surface of the weight layer 60 and the sacrificial substrate 99 are temporarily bonded via the adhesive layer 98.

  Next, as shown in FIG. 33, the lower surface of the single crystal silicon layer 10 is retracted by performing grinding, polishing, and CMP in this order. At this time, the end point of CMP is set after a predetermined time has elapsed after the lower surface of the stopper layer 32 is exposed. Then, as shown in FIG. 28C, the lower surface of the stopper layer 32 can be protruded from the lower surface of the single crystal silicon layer 10 by a predetermined height h. The height at which the lower surface of the stopper layer 32 protrudes from the lower surface of the single crystal silicon layer 10 is, for example, 5 μm. At this time, the sidewall 31 may be used for CMP end point control. In this case, in order to cause the sidewall 31 to function as a stopper layer, a material that serves as a stopper for the CMP of the single crystal silicon layer 10 is employed as the material of the sidewall layer 31 that serves as the sidewall 31.

  Thereafter, post-processes such as dicing and packaging are performed to complete the acceleration sensor 3 shown in FIG.

4). Fourth Embodiment FIG. 34 shows a sensor die 4A of an acceleration sensor that is a fourth embodiment of the MEMS sensor of the present invention. In FIG. 34, the interface of the layers constituting the sensor die 4A is indicated by a broken line, and the boundary of the functional elements constituting the sensor die 4A is indicated by a solid line. As shown in FIG. 34, the stopper layer 33 may be continuously formed as a surface layer of the flexible portion F. The stopper layer 33 is made of silicon nitride. The stopper layer 33 may be made of other insulating materials such as aluminum nitride, aluminum oxide, tantalum oxide, and titanium oxide. In the flexible portion F, the stopper layer 33 is formed in a bottomed cylindrical shape and penetrates the first insulating layer 20 and the single crystal silicon layer 10. The lower surface of the single crystal silicon layer 10 and the lower surface of the stopper layer 33 are flat and continuous. A core layer 34 is laminated on the upper surface of the stopper layer 33. The recess 10 h of the single crystal silicon layer 10 and the hole 20 h of the first insulating layer 20 are completely filled with the core layer 34. On the upper surface of the flexible portion F, the upper surface of the core layer 34 and the upper surface of the stopper layer 33 are flat and continuous. A contact hole for the piezoresistive element 131 is formed in the stopper layer 33 constituting the upper layer of the flexible portion F. The surface conducting wire layer 50 is formed on the surface of the stopper layer 33.

(Production method)
After performing the process corresponding to FIG. 6 described in the first embodiment, the single crystal silicon layer 10 exposed from the hole 20 h and the surface of the first insulating layer 20 serve as a CMP stopper for the single crystal silicon layer 10. By depositing an insulating material, a stopper layer 33 is formed as shown in FIG. For example, a silicon nitride film having a thickness of 0.2 μm is formed as the stopper layer 33 by the CVD method. As the stopper layer 33, a film of aluminum nitride, aluminum oxide, tantalum oxide, titanium oxide, or the like may be formed. Since the stopper layer 33 is composed of an insulating film, the first insulating layer 20 may be omitted.

  Next, by forming the core layer 34 on the upper surface of the stopper layer 33, the hole 20h and the recess 10h are completely filled as shown in FIG. For example, as the core layer 34, a silicon oxide film having a thickness of 10 μm is formed by a CVD method. Since the core layer 34 does not need a function as a stopper, the material of the core layer 34 can be widely selected in consideration of rigidity, strength, stress, density, throughput, and the like. For example, a film made of polycrystalline silicon, aluminum nitride, aluminum oxide, tantalum oxide, titanium oxide, tungsten silicide, molybdenum silicide, copper, or the like may be formed as the core layer 34.

  Next, the surface layer of the core layer 34 is removed by, for example, CMP until the stopper layer 33 is exposed as shown in FIG. As a result, the core layer 34 remains only inside the hole 20h and the recess 10h, and the upper surface of the core layer 34 and the upper surface of the stopper layer 33 are continuously flat. At this time, the stopper layer 33 functions as a CMP stopper for the core layer 34.

  Next, the low resistance portion 131b, the surface conducting wire layer 50, and the flexible portion F are formed in the same manner as in the first embodiment.

  Next, as shown in FIG. 39, the lower surface of the single crystal silicon layer 10 is sequentially retracted by grinding, polishing, and CMP until the stopper layer 33 is exposed. At this time, the lower surface of the stopper layer 33 functions as a CMP stopper. Since the stopper layer 33 is made of a material different from that of the single crystal silicon layer 10, the thickness of the single crystal silicon layer 10 can be accurately adjusted based on the depth at which the stopper layer 33 is embedded in the single crystal silicon layer 10. Can do.

  Thereafter, when a post-process such as dicing is performed, the sensor die 4A shown in FIG. 34 is completed.

5). Fifth Embodiment FIG. 40 shows an acceleration sensor 5 that is a fifth embodiment of the MEMS sensor of the present invention. In FIG. 40A, FIG. 40B, and FIG. 40C, the interfaces of the layers that constitute the sensor die 5A are indicated by broken lines, and the boundaries of the functional elements that constitute the sensor die 5A are indicated by solid lines. 40A and 40B correspond to the AA line and the BB line shown in FIG. 1C, respectively.

(Production method)
In the present embodiment, a manufacturing method will be described in which a layer that functions as a CMP stopper for the single crystal silicon layer 10 when the thickness of the flexible portion F is adjusted disappears in the manufacturing process and does not exist in a completed state. 41 to 45 correspond to the cross section shown in FIG. 40B except for FIGS. 41A, 42A, and 43A. 41A, 42A, and 43A correspond to the cross section shown in FIG. 40A.

  First, after performing the steps corresponding to FIG. 6 described in the first embodiment, the surface of the single crystal silicon layer 10 and the first insulating layer 20 exposed from the hole 20h is formed on the surface of FIG. The stopper layer 33 and the core layer 34 are laminated as shown in FIG. However, the recess 10 h formed in the single crystal silicon layer 10 and the hole 20 h formed in the first insulating layer 20 correspond to the pattern of the gap between the flexible portion F and the support portion S. That is, a pattern corresponding to the flexible portion F is formed when the recess 10h and the hole 20h are formed. As the material of the core layer 34, a wide range of materials that can be used as a stopper for the CMP of the single crystal silicon layer 10 such as silicon oxide and photoresist can be used. In this embodiment, the core layer 34 serves as a stopper for the CMP of the single crystal silicon layer 10 and is not the stopper layer 33, but the names used in other embodiments are used for the sake of simplicity. The code is used as it is.

  Next, as in the first embodiment, the low resistance portion 131b and the surface conductor layer 50 are formed, and the surface on which the surface conductor layer 50 is formed is temporarily bonded to the sacrificial substrate 99 as shown in FIG.

  Next, as shown in FIG. 43, the lower surface of the single crystal silicon layer 10 is sequentially retreated by grinding, polishing, and CMP until the core layer 34 is exposed. At this time, the core layer 34 functions as a CMP stopper. Since the core layer 34 is made of a material (silicon oxide) different from that of the single crystal silicon layer 10, the thickness of the single crystal silicon layer 10 is accurately determined based on the depth at which the core layer 34 is embedded in the single crystal silicon layer 10. Can be adjusted.

  Next, as shown in FIG. 44, the weight layer 60 is cut along the groove 60h, and the weight portion M is released.

Next, as shown in FIG. 45, the core layer 34 is removed by etching. As a result, the side surface constituted by the stopper layer 33 of the flexible portion F is exposed. For example, the core layer 34 made of silicon oxide is removed by reactive ion etching using CHF ₃ or CF ₄ + H ₂ as an etching gas. Further, for example, the core layer 34 made of a photoresist is removed by dry etching using O ₂ plasma.

  Thereafter, when post-processes such as dicing and packaging are performed, the acceleration sensor 5 shown in FIG. 40 is completed. When forming the recess 10h of the single crystal silicon layer 10 and the hole 20h of the first insulating layer 20, a groove for dividing the single crystal silicon layer 10 and the first insulating layer 20 for each die is formed at the same time. It may be left. In this case, the single crystal silicon layer 10 and the first insulating layer 20 can be divided for each die by etching the core layer 34 without using a dicer.

6). Sixth embodiment (Configuration)
46 and 47 show an acceleration sensor 6 that is a sixth embodiment of the MEMS sensor of the present invention. 46 and 47, the interface of the layers constituting the sensor die 6A is indicated by a broken line, and the boundaries of the functional elements constituting the sensor die 6A are indicated by a solid line.

In the present embodiment, three layers of the first insulating layer 20, the second insulating layer 35, and the stopper layer 36 are formed between the piezoresistive element 131 and the surface conducting wire layer 50. The second insulating layer 35 is made of a silicon oxide film having a thickness of 0.2 μm. As a material of the second insulating layer 35, silicon nitride, aluminum nitride, aluminum oxide, tantalum oxide, titanium oxide, or the like may be used. The stopper layer 36 is made of a titanium nitride film having a thickness of 0.5 μm. The material of the stopper layer 36 may be a stopper for CMP of the single crystal silicon layer 10, and tantalum nitride, titanium oxynitride (TiO _x N _y ), or the like may be used.

(Production method)
After performing the steps corresponding to FIG. 6 described in the first embodiment, as shown in FIG. 48, the single crystal silicon layer 10 exposed from the hole 20 h of the first insulating layer 20 and the upper surface of the first insulating layer 20 The second insulating layer 35, the stopper layer 36, and the core layer 37 are laminated. For example, a silicon oxide film is formed as the second insulating layer 35 and a titanium nitride film is formed as the stopper layer 36 by the CVD method. Subsequently, the core layer 37 is formed on the upper surface of the stopper layer 36, thereby completely filling the hole 20h and the recess 10h. For example, a copper film having a thickness of 10 μm is formed as the core layer 37 by electroplating. The material of the core layer 37 may be appropriately selected from the viewpoint of stress control, void prevention, throughput improvement, density, and the like. For example, the core layer 37 may be made of a metal such as gold (Au), silver (Ag), tin (Sn), nickel, palladium, platinum (Pt) or an alloy such as AuSn, NiFe, PtPd.

  Next, as shown in FIG. 49, the surface layer of the core layer 37 is removed by, for example, CMP until the stopper layer 36 is exposed. At this time, the stopper layer 36 functions as a CMP stopper. As a result, the upper surface of the core layer 37 and the upper surface of the stopper layer 36 are continuously flat.

  Next, as in the first embodiment, the low resistance portion 131b, the surface conducting wire layer 50, and the flexible portion F are formed, and the weight layer 60 is joined.

  Next, as shown in FIGS. 50 and 51, the lower surface of the single crystal silicon layer 10 is sequentially retracted by grinding, polishing and CMP until the stopper layer 36 is exposed. At this time, the stopper layer 36 can be used for end point control of CMP. That is, since the stopper layer 36 is made of a material different from that of the single crystal silicon layer 10, the thickness of the single crystal silicon layer 10 is accurately adjusted based on the depth at which the stopper layer 36 is embedded in the single crystal silicon layer 10. can do.

  Thereafter, when a process such as dicing is performed as in the first embodiment, a sensor die 5A shown in FIG. 46 is completed.

7). Seventh embodiment (Configuration)
FIG. 52 shows an acceleration sensor 7 which is a seventh embodiment of the MEMS sensor of the present invention. In FIGS. 52A and 52B, the interface of the layers constituting the sensor die 7A is indicated by a broken line, and the boundary of the functional elements constituting the sensor die 7A is indicated by a solid line.

  An electronic component 7C functioning as an LSI or interposer connected to the sensor die 7A may be provided between the package 1B and the sensor die 7A. In this case, the electronic component 7 </ b> C and the sensor die 7 </ b> A are connected via the conductive adhesive layer 96. The conductive adhesive layer 96 is composed of an anisotropic conductive film or the like.

  The through electrode P penetrates the support portion S at a plurality of locations of the support portion S, and is connected to the bonding pad constituted by the surface conductive layer 50 and the conductive adhesive layer 96. Each of the plurality of through electrodes P is constituted by a stopper layer 36 and a core layer 37. That is, when adjusting the thickness of the flexible portion F, the acceleration sensor 7 can be downsized by causing the stopper layer 36 functioning as a CMP stopper for the single crystal silicon layer 10 to also function as the through electrode P. The stopper layer 36 and the core layer 37 are made of a conductive material. For example, the stopper layer 36 is made of a titanium nitride film having a thickness of 0.5 μm. The core layer 37 is made of a copper film having a thickness of 10 μm. Sidewalls 31 are formed between the stopper layer 36 and the second insulating layer 35.

(Production method)
As shown in FIG. 53, the first insulating layer 20 and the upper surface of the single crystal silicon layer 10 exposed from the hole 20h of the first insulating layer 20 after performing the process corresponding to FIG. 6 described in the first embodiment. A second insulating layer 35 is formed. For example, a silicon oxide film having a thickness of 0.2 μm is formed as the second insulating layer 35 by the CVD method. As a material of the second insulating layer 35, silicon nitride, aluminum nitride, aluminum oxide, tantalum oxide, titanium oxide, or the like may be used.

  Next, as shown in FIG. 54, a sidewall layer 31 is formed on the upper surface of the second insulating layer 35 as in the second embodiment.

  Next, as shown in FIG. 55, the sidewall 31 is formed by anisotropically etching the sidewall layer 31 as in the second embodiment.

  Next, as shown in FIG. 56, a stopper layer 36 that covers the sidewall 31 is formed on the upper surface of the second insulating layer 35. For example, a titanium nitride film having a thickness of 0.5 μm is formed as the stopper layer 36 by the CVD method. Subsequently, the recess 10h and the hole 20h are completely filled by growing the core layer 37 on the upper surface of the stopper layer 36 by plating. For example, a copper film having a thickness of 10 μm is formed as the core layer 37 by electroplating. At this time, since the sidewall 31 is formed on the side surfaces of the recess 10h and the hole 20h, the step coverage of the stopper layer 36 and the core layer 37 is improved.

  Next, as shown in FIG. 57, the surface layer of the core layer 37 is removed by, for example, CMP until the stopper layer 36 is exposed. At this time, the stopper layer 36 functions as a CMP stopper.

  Next, as in the first embodiment, the low resistance portion 131b, the surface conducting wire layer 50, and the flexible portion F are formed, and the weight layer 60 is joined.

  Next, as shown in FIGS. 58 and 59, the lower surface of the single crystal silicon layer 10 is sequentially retreated by grinding, polishing and CMP until the stopper layer 36 is exposed. As a result, the thickness of the single crystal silicon layer 10 is adjusted, and the through electrode P including the stopper layer 36 and the core layer 37 is exposed from the lower surface of the single crystal silicon layer 10. At this time, the stopper layer 36 is used for end point control of CMP. That is, since the stopper layer 36 is made of a material different from that of the single crystal silicon layer 10, the thickness of the single crystal silicon layer 10 is accurately adjusted based on the depth at which the stopper layer 36 is embedded in the single crystal silicon layer 10. can do.

  Thereafter, when post-processes such as dicing and packaging are performed as in the first embodiment, the acceleration sensor 7 shown in FIG. 52 is completed. In the packaging step, the electronic component 7C is bonded to the base 90 of the package 1B via the adhesive layer 92, and the electronic component 7C and the sensor die 7A are bonded via the conductive adhesive layer 96. The electronic component 7C and the sensor die 7A are bonded to each other through the conductive adhesive layer 96, whereby a lead wire (not shown) provided in the electronic component 7C and the through electrode of the sensor die 7A are connected.

8). Eighth Embodiment The present invention can also be applied to MEMS sensors other than acceleration sensors, such as angular velocity sensors. FIG. 60 shows a vibrating gyroscope 8 which is a MEMS sensor as an eighth embodiment of the present invention. FIG. 60B is a top view of the sensor die 8A. 60A is a cross-sectional view corresponding to the line AA shown in FIG. 60B. In FIGS. 60A and 60C, the interface of the layers constituting the sensor die 8A is indicated by a broken line, and the boundary of the functional elements constituting the sensor die 8A is indicated by a solid line.

(Constitution)
The vibrating gyroscope 8 of this embodiment includes a sensor die 8A housed in a package 1B, and detects three-axis angular velocity components orthogonal to each other.

  The sensor die 7 </ b> A is a laminate composed of a single crystal silicon layer 10, a first insulating layer 20, a stopper layer 33, a core layer 34, electrode layers 81 and 83, a piezoelectric layer 82, an adhesive layer 61, and a weight layer 60. It is a structure. The electrode layers 81 and 83 are made of platinum (Pt). The electrode layers 81 and 83 have a thickness of 0.1 μm. The piezoelectric layer 82 is made of PZT (lead zirconate titanate). The thickness of the piezoelectric layer 82 is 3 μm.

  The sensor die 7A includes a support portion S, a flexible portion F that is a circular membrane stretched inside the support portion S, a weight portion M, and a detection piezoelectric element as a detecting means provided in the flexible portion F. An element 80a and a driving piezoelectric element 80b as a driving means provided in the flexible portion F are provided. The outer periphery of the flexible portion F is coupled to the inner periphery of the support portion S. The thickness of the flexible portion F is 20 μm, which is the sum of the thickness of the single crystal silicon layer 10 and the thickness of the first insulating layer 20. A stopper layer 33 and a core layer 34 are embedded in the central portion of the flexible portion F. On the lower surface of the flexible portion F, the lower surface of the single crystal silicon layer 10 and the lower surface of the stopper layer 33 are flat and continuous. On the upper surface of the flexible part F, the upper surface of the core layer 34 and the upper surface of the first insulating layer 20 are flat and continuous.

  The detecting piezoelectric element 80 a and the driving piezoelectric element 80 b are constituted by electrode layers 81 and 83 and a piezoelectric layer 82. By applying alternating excitation voltages having different phases to the four driving piezoelectric elements 80b, the weight M rotates. When the sensor die 8A rotates, an alternating voltage signal corresponding to the Coriolis force acting on the weight M is output from the four detection piezoelectric elements 80a. By removing the excitation component from this voltage signal, the angular velocity component of the sensor die 8A can be obtained.

(Production method)
First, as shown in FIG. 61, the first insulating layer 20 is formed on the upper surface of the single crystal silicon wafer 10 to be the single crystal silicon layer 10. As the first insulating layer 20, a silicon dioxide film having a thickness of 1 μm is formed by, for example, thermal oxidation or CVD. Subsequently, by performing the steps corresponding to FIGS. 5 and 6 described in the first embodiment, the holes 20 h are formed in the first insulating layer 20, and the recesses 10 h are formed in the single crystal silicon wafer 10.

  Next, as shown in FIG. 62, the stopper layer 33 and the core are formed on the upper surfaces of the single crystal silicon layer 10 and the first insulating layer 20 by performing the steps corresponding to FIGS. 35 and 36 described in the fourth embodiment. Layer 34 is laminated. Subsequently, the core layer 34 and the stopper layer 33 are etched back until the first insulating layer 20 is exposed.

  Next, as shown in FIG. 63, the electrode layer 81, the piezoelectric layer 82, and the electrode layer 83 are laminated in this order on the top surfaces of the first insulating layer 20 and the core layer 34. As the electrode layer 81, a platinum film having a thickness of 0.1 μm is formed by sputtering, for example. As the piezoelectric layer 82, a PZT film having a thickness of 3 μm is formed by sputtering, for example. As the electrode layer 83, a platinum film having a thickness of 0.1 μm is formed by sputtering, for example.

  Next, as shown in FIG. 64, the electrode layer 83 and the piezoelectric layer 82 are patterned into a predetermined shape by etching using a protective film R9 made of a photoresist. For example, the electrode layer 83 and the piezoelectric layer 82 are anisotropically etched by a milling method using argon (Ar) ions.

  Next, as shown in FIG. 65, the electrode layer 81 is patterned into a predetermined shape by etching using a protective film R10 made of a photoresist. For example, the electrode layer 81 is anisotropically etched by a milling method using argon (Ar) ions. As a result, the driving piezoelectric element 80b and the detecting piezoelectric element 80a are formed.

  Next, as shown in FIG. 66, the thickness of the single crystal silicon layer 10 is adjusted by performing the steps corresponding to FIGS. 38 and 39 described in the fourth embodiment.

  Thereafter, the weight portion M is formed in the same manner as in the first embodiment, and the steps such as dicing and packaging are performed, thereby completing the vibrating gyroscope 8 shown in FIG.

9. Ninth Embodiment FIG. 67 shows an acceleration sensor 9 as a ninth embodiment of the present invention. In FIG. 67, the interfaces of the layers constituting the sensor die 9A are indicated by broken lines, and the boundaries of the functional elements constituting the sensor die 9A are indicated by solid lines.

(Constitution)
The sensor die 9A is a stacked structure including the weight layer 60, the epitaxial crystal layer 11, the stopper layer 30, and the surface conductive layer 50, and is accommodated in the package 1B. Epitaxial crystal layer 11 is made of p-type single crystal silicon. The thickness of the epitaxial crystal layer 11 is 10 μm. The stopper layer 30 is made of an insulating material that functions as a CMP stopper for the single crystal silicon wafer 10 as in the first embodiment and functions as an interlayer insulating film between the surface conductive layer 50 and the piezoresistive element 131. Is made of silicon nitride as in the first embodiment.

  The flexible part F is a circular membrane. The outer periphery of the flexible portion F is coupled to the inner periphery of the support portion S. The support part S includes a weight layer 60 and a stopper layer 30. The central portion of the flexible portion F is coupled to the weight portion M. The flexible portion F includes the epitaxial crystal layer 11 and the stopper layer 30. The upper surface of the flexible part F is formed from the upper surface of the stopper layer 30. The lower surface of the flexible portion F includes the lower surface of the epitaxial crystal layer 11 and the lower surface of the stopper layer 30. The lower surface of the epitaxial crystal layer 11 and the lower surface of the stopper layer 30 are flat and continuous. The stopper layer 30 stacked on the upper surface of the epitaxial crystal layer 11 penetrates the epitaxial crystal layer 11 in the central portion of the flexible portion F and is coupled to the weight portion M.

(Production method)
First, as shown in FIG. 68, epitaxial crystal layer 11 is formed on the upper surface of single crystal silicon wafer 10. For example, a p-type silicon film having a thickness of 10 μm is epitaxially grown on the upper surface of the n-type single crystal silicon wafer 10 as the epitaxial crystal layer 11.

  Next, as shown in FIG. 69, the epitaxial crystal layer 11 is patterned by crystal anisotropic etching using a protective film R <b> 11 made of a photoresist to form a tapered hole 11 h as a through hole in the epitaxial crystal layer 11. Specifically, the lower surface of the single crystal silicon wafer 10 is temporarily bonded to a support plate (not shown) using wax as an adhesive layer, and the epitaxial crystal layer 11 is patterned by electrochemical etching while immersed in an etching solution. Then, the p-type epitaxial crystal layer 11 can be selectively etched with respect to the n-type single crystal silicon wafer 10. The epitaxial crystal layer 11 may be n-type and the single crystal silicon wafer may be p-type.

  Next, as shown in FIG. 70, a high resistance portion 131a is formed in the epitaxial crystal layer 11 by introducing impurities using a protective film R12 made of a photoresist.

Next, as shown in FIG. 71, a stopper layer 30 is laminated on the upper surface of the epitaxial crystal layer 11 and the upper surface of the single crystal silicon wafer 10 exposed from the tapered hole 11h. At this time, since the through hole of the epitaxial crystal layer 11 exposing the single crystal silicon wafer 10 is the tapered hole 11h, the step coverage of the stopper layer 30 is improved. Specifically, a silicon nitride film having a thickness of 15 μm is formed as the stopper layer 30 by, eg, CVD. As the stopper layer 30, a nitride film such as aluminum nitride (Al _x N _y ) or titanium nitride (Ti _x N _y ) may be formed, or silicon oxide (SiO _x ) or aluminum oxide (Al _x O _y). ), Tantalum oxide (TaO _x ), titanium oxide (TiO _x ), or other oxide films, tungsten silicide (WSi _x ), molybdenum silicide (MoSi _x ), titanium silicide (TiSi _x ), or the like. A film of a silicide compound may be formed, or a film of a metal such as copper (Cu), nickel (Ni), platinum (Pt), or gold (Au) may be formed.

  Next, as shown in FIG. 72, a contact hole is formed in the stopper layer 30 by etching using a protective film R4 made of photoresist, and the steps corresponding to FIGS. 10 and 11 described in the first embodiment are performed. By implementing, the low resistance part 131b is formed.

  Next, after forming the surface conducting wire layer 50 as in the first embodiment, the single crystal silicon wafer 10 is removed as shown in FIGS. Specifically, the lower surface of the single crystal silicon wafer 10 is sequentially retracted by grinding, polishing and CMP until the stopper layer 30 is exposed, that is, until the single crystal silicon wafer 10 disappears. At this time, the stopper layer 30 made of a material different from that of the single crystal silicon wafer 10 can be used for CMP end point control. Note that the CMP end point may be set after a lapse of a certain time from the time when the stopper layer 30 is exposed and the single crystal silicon wafer 10 disappears.

  Thereafter, the weight layer 60 is formed by carrying out the steps corresponding to FIGS. 26 and 27 described in the second embodiment, and when the steps such as dicing and packaging are carried out, the acceleration sensor 9 shown in FIG. 67 is completed. .

10. Tenth Embodiment (Configuration)
FIG. 75 shows a vibrating gyroscope 100 that is the tenth embodiment of the MEMS sensor of the present invention. 75A, 75B, and 75D, the interfaces of the layers that constitute the sensor die 100A are indicated by broken lines, and the boundaries of the functional elements that constitute the sensor die 100A are indicated by solid lines.

  The vibration gyroscope 100 is an angular velocity sensor for detecting a uniaxial angular velocity component. As shown in FIG. 75C, the vibration gyroscope 100 includes a support portion S, two flexible portions F having one end coupled to the support portion S, and detection as detection means provided in each flexible portion F. Piezoelectric element 80c for driving and driving piezoelectric element 80d as driving means provided in each flexible portion F. Note that the boundary between the flexible portion F and the support portion S is indicated by a broken line in FIG. 75C.

  The flexible portion F constitutes a cantilever beam whose one end is coupled to the support portion S. The flexible portion F and the support portion S include a single crystal silicon layer 10 and a first insulating layer 20. The thickness of the flexible part F is 20 μm. As will be described later, the thickness of the flexible portion F is adjusted with reference to the lower surface of the stopper layer 33 that has disappeared in the completed state.

  The detecting piezoelectric element 80 c and the driving piezoelectric element 80 d are composed of electrode layers 81 and 83 and a piezoelectric layer 82. One end of the electrode layer 81 constitutes a bonding pad 81a common to the detecting piezoelectric element 80c and the driving piezoelectric element 80d. One end of the electrode layer 83 constitutes a bonding pad 83a unique to each of the detecting piezoelectric element 80c and the driving piezoelectric element 80d. By applying an alternating excitation voltage to the two driving piezoelectric elements 80d, the free ends of the two flexible portions F vibrate in the direction perpendicular to the paper surface in FIG. 75C. When the sensor die 100A rotates around an axis parallel to the length direction of the flexible portion F (vertical direction in FIG. 75C), the flexible portion F is twisted according to the Coriolis force acting on the flexible portion F. By removing the excitation component from the voltage signals output from the four detection piezoelectric elements 80c, an angular velocity component around an axis parallel to the length direction of the flexible portion F of the sensor die 100A is obtained.

  As shown in FIG. 75D, an electronic component 10C is provided between the sensor die 100A and the package 1B. The sensor die 100A and the electronic component 10C are connected via an adhesive layer 97 including beads 97a as spacers. The electronic component 10C is bonded to the bottom surface 90a of the package 1B via an adhesive layer 92.

(Production method)
First, steps corresponding to FIGS. 4, 5 and 6 described in the first embodiment are performed. As a result, as shown in FIG. 76, the first insulating layer 20 is laminated on the upper surface of the single crystal silicon layer 10, the hole 20h is formed in the first insulating layer 20, and the recess 10h is formed in the single crystal silicon layer 10. . When the hole 20h and the recess 10h are formed, they are formed so as to surround the support portion S and the flexible portion F in a completed state. That is, the pattern of the support part S and the flexible part F is formed by forming the hole 20h and the recessed part 10h.

  Next, steps corresponding to FIGS. 35 to 37 described in the fourth embodiment are performed. However, when the core layer 34 is etched back, the core layer 34 is etched until the stopper layer 33 is exposed and further the first insulating layer 20 is exposed. As a result, as shown in FIG. 77, the upper surface of the core layer 34 and the upper surface of the first insulating layer 20 are continuously flat.

  Next, the steps corresponding to FIGS. 63 to 66 described in the seventh embodiment are performed, and the thickness of the single crystal silicon layer 10 is adjusted with reference to the lower surface of the stopper layer 33 as shown in FIG. When the thickness of the flexible portion F is adjusted by retracting the lower surface of the single crystal silicon layer 10, the stopper layer 33 functions as a CMP stopper for the single crystal silicon layer 10. For this reason, the thickness of the flexible portion F can be accurately adjusted based on the lower surface of the stopper layer 33. The CMP for the single crystal silicon layer 10 may be terminated when the stopper layer 33 is exposed, may be terminated after a predetermined time has elapsed after the stopper layer 33 is exposed, or when the core layer 34 is exposed. Or may be terminated after elapse of a predetermined time after the core layer 34 is exposed. That is, the core layer 34 may function as a CMP stopper for the single crystal silicon layer 10.

  Next, as shown in FIG. 79, the stopper layer 33 is removed by etching. Specifically, the stopper layer 33 made of silicon nitride is etched away using phosphoric acid heated to 80 ° C. As a result, the core layer 34 is bonded only to the adhesive layer 98. Therefore, when the adhesive layer 98 is peeled off, the sensor die 100A divided for each die is obtained.

11. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, it is a matter of course that various constituent elements illustrated in different embodiments can be combined. In addition, the materials, dimensions, film forming methods, and pattern transfer methods shown in the above embodiment are merely examples, and descriptions of addition and deletion of processes and replacement of the process order that are obvious to those skilled in the art are omitted. Yes. Also, for example, in the above-described manufacturing process, the film composition, film forming method, film contour forming method, process sequence, etc. are appropriately selected according to the combination of film materials, film thickness, required contour shape accuracy, etc. There is no particular limitation.

FIG. 1A is a cross-sectional view according to the first embodiment of the present invention. FIG. 1B is a cross-sectional view according to the first embodiment of the present invention. FIG. 1C is a top view according to the first embodiment of the present invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. FIG. 5A is a sectional view according to the first embodiment of the present invention. FIG. 5B is a top view according to the first embodiment of the present invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. FIG. 13A is a sectional view according to the first embodiment of the present invention. FIG. 13B is a cross-sectional view according to the first embodiment of the present invention. FIG. 13C is a top view according to the first embodiment of the present invention. FIG. 14A is a sectional view according to the first embodiment of the present invention. FIG. 14B is a cross-sectional view according to the first embodiment of the present invention. FIG. 14C is a top view according to the first embodiment of the present invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. FIG. 19A is a sectional view according to the second embodiment of the present invention. FIG. 19B is a cross-sectional view according to the second embodiment of the present invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. FIG. 28A is a sectional view according to a third embodiment of the present invention. FIG. 28B is a sectional view according to the third embodiment of the present invention. FIG. 29C is a partially enlarged view of FIG. 28B. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. FIG. 40A is a cross-sectional view according to a fifth embodiment of the present invention. FIG. 40B is a sectional view according to the fifth embodiment of the present invention. FIG. 40C is a sectional view according to the fifth embodiment of the present invention. FIG. 41A is a cross-sectional view according to a fifth embodiment of the present invention. FIG. 41B is a sectional view according to the fifth embodiment of the present invention. FIG. 42A is a sectional view according to the fifth embodiment of the present invention. FIG. 42B is a sectional view according to the fifth embodiment of the present invention. FIG. 43A is a sectional view according to a fifth embodiment of the present invention. FIG. 43B is a sectional view according to the fifth embodiment of the present invention. Sectional drawing concerning 5th embodiment of this invention. The bottom view concerning a fifth embodiment of the present invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. FIG. 52A is a sectional view according to the seventh embodiment of the present invention. FIG. 52B is a sectional view according to the seventh embodiment of the present invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. FIG. 60A is a sectional view according to the eighth embodiment of the present invention. FIG. 60B is a top view according to the eighth embodiment of the present invention. FIG. 60C is a sectional view according to the eighth embodiment of the present invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. FIG. 67A is a sectional view according to the ninth embodiment of the present invention. FIG. 67B is a sectional view according to the ninth embodiment of the present invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. FIG. 75A is a sectional view according to the tenth embodiment of the present invention. FIG. 75B is a sectional view according to the tenth embodiment of the present invention. FIG. 75C is a top view according to the tenth embodiment of the present invention. FIG. 75D is a top view according to the tenth embodiment of the present invention. Sectional drawing concerning 10th Embodiment of this invention. Sectional drawing concerning 10th Embodiment of this invention. Sectional drawing concerning 10th Embodiment of this invention. Sectional drawing concerning 10th Embodiment of this invention.

Explanation of symbols

1: acceleration sensor, 1A: sensor die, 1B: package, 2: acceleration sensor, 2A: sensor die, 3: acceleration sensor, 3A: sensor die, 4A: sensor die, 5: acceleration sensor, 5A: sensor die, 6: acceleration sensor, 7 : Acceleration sensor, 7A: sensor die, 7C: electronic component, 8: vibration gyroscope, 8A: sensor die, 9: acceleration sensor, 9A: sensor die, 10: single crystal silicon layer, 100A: sensor die, 10C: electronic component, 10h: Recess, 11: Epitaxial crystal layer, 11h: Tapered hole, 20: First insulating layer, 20h: Hole, 30: Stopper layer, 31: Side wall, 32: Stopper layer, 33: Stopper layer, 34: Core layer, 35 : Second insulating layer, 36: stopper layer, 37: core layer, 40: second insulating layer, 50: surface conductor layer, 60: Layer, 60h: groove, 61: adhesive layer, 70: third insulating layer, 80a: piezoelectric element for detection, 80b: piezoelectric element for driving, 80c: piezoelectric element for detection, 81: electrode layer, 81a: bonding pad, 82 : Piezoelectric layer, 83: Electrode layer, 83a: Bonding pad, 90: Base, 90a: Bottom surface, 91: Through electrode, 92: Adhesive layer, 93: Adhesive layer, 94: Cover, 95: Wire, 96: Conductive adhesion Layer 97a: beads 98: adhesive layer 99: sacrificial substrate 100: vibrating gyroscope 131: piezoresistive element 131a: high resistance part 131b low resistance part G: gap H3: contact hole M : Weight part, P: penetrating electrode, R1: protective film, R2: protective film, R3: coating, R4: protective film, R5: protective film, R6: protective film, R7: protective film, R8: protective film, R9: Protective film, R1 : Protective film, R11: protective film, S: supporting unit, W: laminated structure

Claims (10)

A support part;
A weight part;
A flexible part that connects the support part and the weight part and deforms as the weight part moves;
Comprising a laminated structure formed with
The laminated structure includes a single crystal silicon layer that constitutes the flexible portion and has a flat bottom surface, and a stopper layer that is laminated on the single crystal silicon layer and is different from the single crystal silicon layer,
The lower surface of the stopper layer and the lower surface of the single crystal silicon layer are included in the same plane, or the lower surface of the stopper layer protrudes from the lower surface of the single crystal silicon layer,
MEMS sensor. The stopper layer is in a region that does not deform with the movement of the weight part,
The MEMS sensor according to claim 1. Further comprising a package to which the support portion is bonded via an adhesive layer;
The lower surface of the stopper layer protrudes from the lower surface of the single crystal silicon layer on the surface of the support portion that is bonded to the package.
The MEMS sensor according to claim 1 or 2. The stopper layer constitutes a conductive through electrode,
The MEMS sensor according to any one of claims 1 to 3. A sidewall is formed between the single crystal silicon layer and the stopper layer.
The MEMS sensor as described in any one of Claim 1 to 4. A method for manufacturing a MEMS comprising a laminated structure in which a supporting part, a weight part, and a flexible part that connects the supporting part and the weight part and deforms as the weight part moves are formed. ,
A concave portion having a predetermined depth is formed by etching on the upper surface of the single crystal silicon wafer to be the flexible portion,
In the recess, a stopper layer different from the single crystal silicon wafer is laminated,
Adjusting the thickness of the flexible portion by retracting the lower surface of the single crystal silicon wafer until at least the stopper layer is exposed;
A method for manufacturing a MEMS sensor. Forming the concave portion in a region not deformed with the movement of the weight portion on the upper surface of the single crystal silicon wafer;
A method for manufacturing the MEMS sensor according to claim 6. A side surface of the flexible portion is exposed by removing the stopper layer by etching;
The manufacturing method of the MEMS sensor of Claim 6 or 7. Forming a sidewall in the recess,
Forming the stopper layer after forming the sidewall;
The manufacturing method of the MEMS sensor as described in any one of Claims 6-8. A method of manufacturing a MEMS sensor comprising a laminated structure in which a support part, a weight part, and a flexible part that connects the support part and the weight part and deforms as the weight part moves are formed. And
Growing an epitaxial crystal layer serving as the flexible portion on a flat upper surface of a single crystal silicon wafer;
Forming a through hole in the epitaxial crystal layer;
A stopper layer that is different from the single crystal silicon wafer is formed on the surface of the single crystal silicon wafer exposed in the through hole,
Adjusting the thickness of the flexible portion by retracting the lower surface of the single crystal silicon wafer until the stopper layer is exposed;
Manufacturing method of a MEMS sensor.

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