JP2008004876A - Manufacturing method of thin film device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thin film device with excellent characteristics to be manufactured efficiently at a low cost. <P>SOLUTION: A manufacturing method of the present thin film device comprises: a step of sequentially forming a lower electrode film 2, an insulating film 3, and an upper electrode film 4 on a substrate 1; a first patterning step of patterning the upper electrode film 4 and the insulating film 3 by using a first mask 13; and a second patterning step of patterning the upper electrode film 4 and the lower electrode film 2, in such a manner as to electrically isolate them from each other by using a second mask 23 that is separately formed at the inner portion from the outer periphery 3e of the insulating film 3, and at least the side in the upper surface of a projected pattern on the basis of the upper electrode film 4 and the insulating film 3 that are patterned in the first patterning step. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a thin film device such as a thin film capacitor or a thin film piezoelectric actuator.

  Thin film devices such as thin film capacitors and thin film piezoelectric actuators include a lower electrode film, an insulating film, and an upper electrode formed by patterning on a substrate. Therefore, in the method of manufacturing a thin film device, the formation method and patterning method of the lower electrode film, the insulating film, and the upper electrode film are important.

  As a conventional manufacturing method of a thin film device, a method of forming and patterning a film in order for each of a lower electrode film, an insulating film, and an upper electrode film (see, for example, JP-A-2001-135143 (Patent Document 1)), A method of forming a lower electrode film, an insulating film, and an upper electrode film on a substrate and then patterning the upper electrode film, the insulating film, and the lower electrode film in order is performed.

  For example, referring to FIG. 9, Patent Document 1 discloses the following method for manufacturing a thin film capacitor. After forming the lower electrode film 2 on the substrate 1 with reference to FIG. 9A, the lower electrode film 2 is patterned with reference to FIG. 9B. Next, referring to FIG. 9C, an insulating film 3 is formed on the substrate 1 and the lower electrode film 2, and then the insulating film 3 is patterned with reference to FIG. 9D. Furthermore, after forming the upper electrode film 4 on the substrate 1, the lower electrode film 2, and the insulating film 3, the upper electrode film 4 is patterned with reference to FIG. However, the method of manufacturing a thin film capacitor disclosed in Patent Document 1 requires three film forming steps and three film patterning steps, and has a problem that the number of manufacturing steps is large and the manufacturing cost is high.

  Further, after forming the lower electrode film, the insulating film, and the upper electrode film on the substrate, the method of sequentially patterning the upper electrode film, the insulating film, and the lower electrode film includes a process of forming three consecutive films, Three film patterning steps are required, and there are problems that the number of manufacturing steps is large and the manufacturing cost is high.

  In contrast to these methods, in order to reduce the manufacturing cost by reducing the number of manufacturing steps, a method of patterning the three films less than three times has also been proposed (for example, JP 2000-150825 A). (See Patent Document 2)). For example, referring to FIG. 10, Patent Document 2 discloses the following method for manufacturing a semiconductor device as a conventional technique. Referring to FIG. 10A, the upper electrode film 4, the insulating film 3 and the lower electrode film 2 are continuously etched almost vertically to be patterned once, and the upper electrode film 4 is referred to by referring to FIG. A method in which the electrode film 4, the insulating film 3 and the lower electrode film 2 are continuously etched in a tapered shape and patterned once, with reference to FIG. 10C, the upper electrode film 4 and the insulating film 3 are substantially vertical. And a method of etching the lower electrode film 2 substantially perpendicularly on the outer periphery of the upper electrode film 4 and the insulating film 3 and then patterning them twice.

  However, in the patterning method as shown in FIG. 10A, the re-attachment and etching damage of the work piece removed by etching on the side surfaces of the upper electrode film 4 and the insulating film 3 are large, and the characteristics of the thin film device are deteriorated. There was a problem. In the patterning method as shown in FIG. 10B, a special etching apparatus for performing taper etching is required, and there is a problem that the cost is increased. Further, in the patterning method as shown in FIG. 10 (c), as in the case of FIG. 10 (a), reattachment and etching of the work piece removed by etching on the side surfaces of the upper electrode film 4 and the insulating film 3 are performed. There was a problem that the damage was large and the characteristics of the thin film device were deteriorated.

In addition, there is a method in which the upper electrode film is continuously etched almost vertically, and then the insulating film and the lower electrode film are etched almost vertically on the outer periphery of the upper electrode film to perform patterning twice. In this method, it is necessary to make an electrical connection with the outside only on the side surface of the lower electrode film, which makes it difficult to make an electrical connection with an external element.
JP 2001-135143 A JP 2000-150825 A

  An object of the present invention is to solve the above-described problems and to provide a method for manufacturing a thin film device that can efficiently manufacture a thin film device having excellent characteristics at low cost.

  The present invention includes a step of sequentially forming a lower electrode film, an insulating film, and an upper electrode film on a substrate, a first patterning step of patterning the upper electrode film and the insulating film using a first mask, Using the second mask formed by separating the upper electrode film and the convex pattern based on the insulating film on the upper surface of the convex pattern based on the patterning step from the outer periphery of the insulating film and at least the side surface thereof. And a second patterning step of patterning the electrode film and the lower electrode film so as to be electrically separated from each other.

  In the method for manufacturing a thin film device according to the present invention, the external mask formed on at least the side surface portion of the second mask can cover the outer peripheral portion of the upper surface of the convex pattern.

  In the method of manufacturing a thin film device according to the present invention, the first photomask is used to form the first mask in the first patterning step, and the first photomask defines the outer periphery of the insulating film. The second photomask is used to form the second mask in the second patterning step, and the second photomask has an outer periphery of the upper electrode film separated from each other. In the planar layout of the first photomask and the second photomask, there is an internal photomask having an internal photomask region that defines the external photomask and an external photomask having an external photomask region that defines the outer periphery of the lower electrode film. The first photomask region and the external photomask region may partially overlap.

  In the method for manufacturing a thin film device according to the present invention, the second patterning step includes a step of patterning the upper electrode film and the lower electrode film by etching, and the time required for etching the entire thickness of the upper electrode film is lower electrode film. The total film thickness etching time can be longer than the required time.

  In the method for manufacturing a thin film device according to the present invention, the upper electrode and the insulating film patterned by the first patterning step and the lower electrode film are covered between the first patterning step and the second patterning step. The second mask is formed on the upper surface of the convex pattern generated on the surface of the conductive film by covering the upper electrode film and the insulating film patterned by the first patterning process. The insulating film can be formed separately from the inner periphery and at least the side surface.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the thin film device which can manufacture the thin film device excellent in the characteristic efficiently and at low cost can be provided.

(Embodiment 1)
An embodiment of a method for manufacturing a thin film device according to the present invention is described with reference to the schematic cross-sectional view of FIG. 1 and the schematic top view of FIG. 2 on a substrate 1 with a lower electrode film 2, an insulating film 3, and an upper electrode film. 4 (see FIG. 1A) and a first patterning step of patterning the upper electrode film 4 and the insulating film 3 using the first mask 13 (FIGS. 1B to 1G) 2 (see FIG. 2 (1)), and the upper electrode film 4 patterned by the first patterning step and the upper surface of the convex pattern based on the insulating film 3, the portion inside the outer periphery 3 e of the insulating film 3 and at least the side surface A second patterning process for patterning the upper electrode film 4 and the lower electrode film 2 so as to be electrically isolated from each other using the second mask 23 formed separately from each other (FIGS. 1H to (H) m), FIG. 2 (2)- Including a reference) and 4).

  According to the above manufacturing method, a stable thin film device with good insulation and high characteristics can be obtained between the upper electrode film 4 and the lower electrode film 2. Moreover, according to the said manufacturing method, since a thin film device is obtained by the process of forming three continuous films | membranes and the film | membrane patterning process of 2 times, the manufacturing cost of a thin film device can be reduced.

  Hereinafter, the manufacturing method of the thin film device of this embodiment will be specifically described. First, referring to FIG. 1A, a lower electrode film 2, an insulating film 3, and an upper electrode film 4 are sequentially formed on a substrate 1 (a step of forming a lower electrode film, an insulating film, and an upper electrode film). .

Here, the material of the substrate 1 is not particularly limited, but from the viewpoint of obtaining a large-sized thin film device that is stable and of high quality even under high temperature film formation conditions, single crystals such as Si and sapphire, Al ₂ O ₃ , yttrium Polycrystals such as stabilized zirconia (YSZ) are preferred.

The material of the lower electrode film 2 varies depending on the formation conditions of the insulating film 3, but the high dielectric constant film or piezoelectric film, which is the insulating film 3 of the thin film capacitor or the thin film piezoelectric actuator, generally has an oxidizing atmosphere (for example, oxygen content). Pt that is stable in a high-temperature oxidizing atmosphere is suitable because it is formed at a high temperature (for example, 500 ° C. or higher) in a pressure of 0.1 kPa or higher. In addition to Pt, platinum group elements such as Ir, oxidation-resistant metal elements such as Au, and conductive oxides such as IrO ₂ and SrRuO ₃ can be used from the same viewpoint. Here, the method for forming the lower electrode film 2 is not particularly limited, but a sputtering method, a vacuum deposition method, or the like is preferable. Note that a Ti film, a Cr film, a TiO ₂ film, a ZrO ₂ film, an Al ₂ O ₃ film, etc. are provided between the lower electrode film 2 and the substrate 1 to ensure adhesion between them and prevent mutual diffusion of atoms. May be formed.

The material of the insulating film 3 is not particularly limited, but in the case of a thin film capacitor, a BaTiO ₃ material or a (Ba, Sr) TiO ₃ (hereinafter referred to as BST) material is suitable. Is preferably a Pb (Zr, Ti) O ₃ type material. Here, the method for forming the insulating film 3 is not particularly limited, and includes sputtering, MOCVD (organometallic chemical vapor volume), spin coating (for example, MOD (metal organic decomposition), sol-gel, etc. ) Etc. can be used. Among these forming methods, the spin coating method is preferable from the viewpoint of inexpensive manufacturing equipment and easy formation of a large-area insulating film.

The material of the upper electrode film 4 is not particularly limited, and is the same as that of the lower electrode film 2 (that is, platinum group elements other than Pt such as Pt and Ir that are stable in a high-temperature oxidizing atmosphere, and oxidation resistance such as Au. Metal elements and conductive oxides such as IrO ₂ and SrRuO ₃ ). Further, Al, Cu, etc., which are cheaper than the material of the lower electrode film 4 and have high conductivity and can be easily processed, can be used. Here, the method for forming the upper electrode film 4 is not particularly limited, but a sputtering method, a vacuum evaporation method, or the like is preferable.

  For example, in a thin film capacitor as a thin film device using a Pt film as the lower electrode film 2, a BST film as the insulating film 3, and a Pt film as the upper electrode film 4, each film is formed as follows. First, a Pt film having a thickness of 0.3 μm as the lower electrode film 2 is formed on the sapphire substrate as the substrate 1 at a substrate temperature of 200 ° C. by a sputtering method. Next, a BST film having a thickness of 0.2 μm is formed on the lower electrode film 2 by spin coating. BST film formation is performed by repeating the film formation process of spin coating, drying at 150 ° C., removal of organic components, and baking at 600 ° C. to 850 ° C. Next, a Pt film having a thickness of 0.3 μm is formed as the upper electrode film 4 on the BST film in the same manner as the formation of the lower electrode film.

  Next, with reference to FIGS. 1B to 1G and FIG. 2A, the upper electrode film 4 and the insulating film 3 are patterned using the first mask 13 (first patterning step). Here, the first patterning step is not particularly limited, but from the viewpoint of performing accurate and efficient patterning, the first mask 13 is formed by photolithography using the first photomask 12, It is preferable to pattern the upper electrode film 4 and the insulating film 3 by the etching method using the first mask 13. FIG. 2 (1) is a schematic top view of the thin film wafer of FIG. 1 (f).

  Hereinafter, the first patterning step will be specifically described. Referring to FIG. 1B, a first photoresist layer 11 is formed on the upper electrode film 4 of the thin film wafer of FIG. 1A (first photoresist layer forming step). There is no restriction | limiting in particular in the method of forming a 1st photoresist layer, Usually, it carries out by apply | coating and drying a photoresist.

Then, referring to FIG. 1 (c), through a first photomask 12 having a first photomask regions P _1, the exposure 10d of the first photoresist layer 11 performs (first photo Resist layer exposure step). Next, referring to FIG. 1D, after separating the first photomask 12 from the first photoresist layer 11, the first photoresist layer 11 is developed, and the first photomask 12 is formed on the upper electrode film 4. A first mask 13 having _one mask region E ₁ is formed (first mask forming step). Here, the first mask region E ₁ of the first mask 13 is formed in a pattern corresponding to the pattern immediately below the _first photomask region P ₁ of the first photomask 12.

Next, referring to FIGS. 1E and 1F and FIG. 2A, the upper electrode film 4 and the insulating film 3 are patterned by etching 10e using the first mask 13 (first etching step). ). Thus, the outer periphery 3e of the insulating film 3 is patterned along the outer periphery 13e of the first mask 13. That is, the outer periphery 3 e of the insulating film 3 is defined by the _first mask region E ₁ in the first mask, and the pattern of the first region E ₁ is the first photomask region P ₁ of the first photomask 12. It corresponds to the pattern. That is, the first photomask region P ₁ of the first photomask 12 defines the outer periphery 3 e of the insulating film 3.

  The etching method in the first etching step is not particularly limited as long as the upper electrode film 4 and the insulating film 3 can be etched. Wet etching for removing unnecessary portions by immersion in an etching solution, and reactivity Either dry etching such as ion etching (RIE) or ion milling is possible, but dry etching is preferred from the viewpoint of high etching anisotropy and accurate patterning.

Next, referring to FIG. 1G, the first mask 13 is removed from the upper electrode film 4, and the patterning (first patterning) of the upper electrode film 4 and the insulating film 3 is completed (first pattern). Mask removal step). Thus, a thin film wafer on which a convex pattern based on the upper electrode film 4 and the insulating film 3 is formed is obtained. Here, the method for removing the first mask is not particularly limited, but from the viewpoint of improving the removal efficiency of the first mask and reducing the damage to the thin film wafer, the method of removing with the O ₂ plasma or the like. Is preferred.

  Next, with reference to FIGS. 1H to 1M and FIGS. 2B to 2D, the upper electrode film 4 and the lower electrode film 2 are patterned using the second mask 23 (second). Patterning step). Here, the second patterning step is not particularly limited, but from the viewpoint of performing accurate and efficient patterning, the second mask 23 is formed by photolithography using the second photomask 22. It is preferable to pattern the upper electrode film 4 and the lower electrode film 2 by etching using the second mask 23. 2 (2), (3), and (4) are schematic top views of the thin film wafer or thin film device of FIGS. 1 (j), (l), and (m), respectively.

  Referring to FIG. 1H, a second photoresist layer 21 is formed on upper electrode film 4 and lower electrode film 2 of the thin film wafer of FIG. 1G (second photoresist layer forming step) ). There is no restriction | limiting in particular in the method of forming a 2nd photoresist layer, Usually, it carries out by apply | coating and drying a photoresist.

Then, referring to FIG. 1 (i), are separated from each other, and the internal photomask 22a having an internal photomask regions P _21, the second constituted by an external photomask 22b having an external photomask region P ₂₂ The second photoresist layer 21 is exposed 20d through the photomask 22 (second photoresist layer exposure step). Here, the second photomask 22 is configured so that the internal photomask region P ₂₁ of the internal photomask 22 a is positioned immediately above the internal region from the region surrounded by the outer periphery 3 e of the insulating film 3. The inner periphery ₂₂ i of the external photomask region P ₂₂ is arranged so as to be located immediately above the outer periphery 3 e of the insulating film 3.

  Next, referring to FIG. 1 (j) and FIG. 2 (2), after separating the second photomask 22 from the second photoresist layer 21, the second photoresist layer 21 is developed, A second mask 23 is formed which is separated into a portion on the upper surface of the convex pattern based on the upper electrode film 4 and the insulating film 3 patterned by the first patterning step and a portion inside the outer periphery 3e of the insulating film 3 and at least a side surface portion. (Second mask forming step).

Here, the second mask 23 is an internal mask region formed in a portion inside the outer periphery 3e of the insulating film 3 on the upper surface of the convex pattern based on the upper electrode film 4 and the insulating film 3 which are separated from each other. An internal mask 23a having E ₂₁ and an external mask 23b having an external mask region E ₂₂ formed on at least the side surface portion of the convex pattern based on the upper electrode film 4 and the insulating film 3 are configured. The internal mask region E ₂₁ is formed in a pattern corresponding to the pattern immediately below the internal photomask region P ₂₁ , and the external mask region E ₂₂ corresponds to the pattern immediately below the external photomask region P _22. Molded with a pattern to Here, the inner periphery ₂₃ i of the outer mask region E ₂₂ of the outer mask ₂₃ b coincides with the outer periphery 3 e of the insulating film 3.

  Next, referring to FIGS. 1K and 1L and FIG. 2C, the upper electrode film 4 and the lower electrode film 2 are patterned by etching 20e using the second mask 23 (second etching). Process).

Here, the outer periphery 4 e of the upper electrode film 4 is defined by the internal mask region E ₂₁ of the internal mask 23 a in the second mask 23. More specifically, the outer periphery 4e of the upper electrode film 4 is patterned along the outer periphery 23e of the internal mask 23a. The pattern of the internal mask region E ₂₁ corresponds to the pattern of the internal photomask region P ₂₁ of the internal photomask 22 a in the second photomask 22.

The outer periphery 2 e of the lower electrode film 2 is defined by the external mask region E ₂₂ of the external mask 23 b in the second mask 23. More specifically, the outer periphery 2e of the lower electrode film 2 is patterned along the outer periphery 23f of the external mask 23b. The pattern of the external mask region E ₂₂ corresponds to the pattern of the external photomask region P ₂₂ of the external photomask 22 b in the second photomask 22.

Therefore, the second photomask 22, internal photomask region P ₂₁ is defines the periphery 4e of the upper electrode film 4, an external photomask region P ₂₂ is a lower electrode film on the external photomask 22b therein photomask 22a 2 outer periphery 2e is defined.

  The etching method in the second etching step is not particularly limited as long as it is a method capable of etching the upper electrode film 4 and the lower electrode film 2, and wet etching for removing unnecessary portions by immersion in an etching solution, and reaction. Either dry etching such as reactive ion etching (RIE) or ion milling is possible, but dry etching is preferred from the viewpoint of high etching anisotropy and accurate patterning.

Next, referring to FIG. 1M, the second mask 23 is removed from the upper electrode film 4 and the lower electrode film 2, and patterning (second patterning) of the upper electrode film 4 and the lower electrode film 2 is performed. Completion (second mask removal step). Here, the method for removing the second mask is not particularly limited, but from the viewpoint of improving the removal efficiency of the second mask and reducing the damage to the thin film wafer, the method of removing with the O ₂ plasma or the like. Is preferred.

  In this way, the lower electrode film 2 having the outer periphery 2e is formed on the substrate 1, and the insulating film 3 having the outer periphery 3e positioned on the inner side of the outer periphery 2e is formed on the lower electrode film 2. Thus, a thin film device is obtained in which the upper electrode film 4 having the outer periphery 4e located inside the outer periphery 3e is formed. That is, a thin film device is obtained in which the lower electrode film 2, the insulating film 3, and the upper electrode film 4 are formed on the substrate 1 so that the outer circumferences thereof are stepwise reduced.

  Referring to FIG. 1, in the first embodiment, as described above, when the second patterning step includes a step of patterning the upper electrode film 4 and the lower electrode film 2 by etching, the entire film thickness of the upper electrode film 4 is obtained. The time required for etching (the time required for etching the entire film thickness, hereinafter the same) is preferably equal to or longer than the time required for etching the entire film thickness of the lower electrode film 2. That is, when the upper electrode film 4 and the lower electrode film 2 are etched, the upper electrode film 4 and the lower electrode film 2 are simultaneously etched, or the upper electrode film 4 finishes the etching later. This is preferable from the viewpoint of avoiding damage to the insulating film 3 in the vicinity of the outer peripheral portion due to the main etching. For example, when the upper electrode film 4 and the lower electrode film 2 are made of the same material, the thickness of the upper electrode film 4 is preferably equal to or greater than the thickness of the lower electrode film 2.

  According to the manufacturing method of the first embodiment, a stable thin film device with good insulation, high characteristics, and stability between the upper electrode film 4 and the lower electrode film 2 can be obtained. In addition, since the thin film device can be obtained by one continuous three film formation process and two film patterning processes by the manufacturing method of the first embodiment, the manufacturing cost of the thin film device can be reduced.

(Embodiment 2)
In another embodiment of the method for manufacturing a thin film device according to the present invention, a lower electrode film 2, an insulating film 3 and an upper electrode are formed on a substrate 1 with reference to the schematic cross-sectional view of FIG. 3 and the schematic top view of FIG. A step of sequentially forming the film 4 (see FIG. 3A) and a first patterning step of patterning the upper electrode film 4 and the insulating film 3 using the first mask 13 (FIGS. 3B to 3G) 4), and a portion inside the outer periphery 3e of the insulating film 3 on the upper surface of the convex pattern based on the upper electrode film 4 and the insulating film 3 patterned by the first patterning step and at least A second patterning step of patterning the upper electrode film 4 and the lower electrode film 2 so as to be electrically isolated from each other using the second mask 23 formed separately from the side surface portion (FIG. 3H) To (m), FIG. In that it includes - a reference) to (4), is similar to the method for manufacturing the first embodiment.

A feature of the manufacturing method of the second embodiment is that, referring to FIG. 3 and FIG. 4, the upper electrode film 4 patterned by the first patterning step and the insulation of the second mask 23 used in the second patterning step. The external mask 23b formed on at least the side surface of the convex pattern based on the film 3 covers the outer peripheral portion of the upper surface of the upper electrode film 4 of the convex pattern patterned by the first patterning step. That is, there is an outer periphery covering region E ₃ of the upper electrode film 4 by the external mask 23b. By forming such an external mask 23b, when the upper electrode film 4 and the lower electrode film 2 are patterned in the second patterning step, the lower electrode film 2 near the outer periphery 3e of the insulating film 3 is erroneously removed. Can be prevented.

  The manufacturing method of the thin film device of Embodiment 2 will be specifically described. First, referring to FIG. 3A, as in the first embodiment, a lower electrode film 2, an insulating film 3 and an upper electrode film 4 are sequentially formed on a substrate 1 (lower electrode film, insulating film and Step of forming upper electrode film).

  Next, referring to FIGS. 3B to 3G and FIG. 4A, as the first patterning step, the first photoresist layer forming step (FIG. 3) is performed in the same manner as in the first embodiment. (B)), a first photoresist layer exposure step (FIG. 3C), a first mask formation step (FIG. 3D), and a first etching step (FIGS. 3E and 3D). f)) and the first mask removing step (FIG. 3G), the upper electrode film 4 and the insulating film are formed using the first mask 13 formed using the first photomask 12. 3 is patterned by etching 10e.

  Next, referring to FIGS. 3H to 3M and FIGS. 4B to 4D, the upper electrode film 4 and the lower electrode film 2 are patterned by etching 20e using the second mask 23. (Second patterning step). Referring to FIG. 3H, a second photoresist layer 21 is formed on upper electrode film 4 and lower electrode film 2 of the thin film wafer of FIG. 3G (second photoresist layer forming step) ).

Then, referring to FIG. 3 (i), are separated from each other, and the internal photomask 22a having an internal photomask regions P _21, the second constituted by an external photomask 22b having an external photomask region P ₂₂ The second photoresist layer 21 is exposed 20d through the photomask 22 (second photoresist layer exposure step).

  Here, the planar layout of the first photomask 12 and the second photomask 22 in Embodiment 2 will be described with reference to the schematic diagram of FIG. The first photomask 12 and the second photomask 22 are both formed on the lower surface of the transparent substrate 120 such as a quartz substrate.

The first photomask 12 has a first photomask region P ₁ that defines the outer periphery 3e of the insulating film 3 (see FIG. 3 (f) and FIG. 4 (1)). More specifically, as described later, the outer periphery 12e of the _first photomask region P1 corresponds to the outer periphery 3e of the insulating film 3. The same applies to the first photomask of Embodiment 1.

The second photomask 22 includes an internal photomask 22 a having an internal photomask region P ₂₁ that defines the outer periphery 4 e of the upper electrode film 4 and an external photomask region that defines the outer periphery 2 e of the lower electrode film 2. It is composed of a external photomask 22b having a P _22. More specifically, as described later, the outer circumference 22e of the inner photomask region P ₂₁ corresponds to the outer periphery 4e of the upper electrode film 4, the outer periphery 2e periphery 22f of the lower electrode film 2 of the outer photomask region P ₂₂ Correspond. In this regard, the same applies to the second photomask of Embodiment 1.

Here, the inner periphery 22 i of the outer photomask region P ₂₁ of the second photomask 22 exists inside the outer periphery 12 e of the first photomask region P ₁ of the first photomask 12. That is, there is an overlapping region P ₃ between the first photomask region P ₁ of the first photomask 12 and the external photomask region P ₂₂ in the second photomask 22.

In the photomask of Embodiment 1, there is no overlapping region between the first photomask region P ₁ of the first photomask 12 and the external photomask region P _{22 of} the second photomask 22. in a planar layout, the inner periphery 22i of outer photomask region P ₂₂ (not shown) which coincides with the first periphery 12e of the photomask region P _1.

  Next, referring to FIG. 3J and FIG. 4B, after the second photomask 22 is separated from the second photoresist layer 21, the second photoresist layer 21 is developed, A second mask 23 is formed on the upper surface of the convex pattern based on the upper electrode film 4 and the insulating film 3 patterned in the first patterning step, on the inner side of the outer periphery 3e of the insulating film 3 and at least on the side surface (first side). (2) Mask formation step).

Here, the second mask 23 is an internal mask region formed in a portion inside the outer periphery 3e of the insulating film 3 on the upper surface of the convex pattern based on the upper electrode film 4 and the insulating film 3 which are separated from each other. An internal mask 23a having E ₂₁ and an external mask 23b having an external mask region E ₂₂ formed on at least the side surface portion of the convex pattern based on the upper electrode film 4 and the insulating film 3 are configured.

As described above, the inner periphery 22i of the outer mask area P ₂₂ of the second photomask 22, since the than the first outer circumference 12e of the photomask region P ₁ of the first photomask 12 positioned on the inside, the The outer mask 23 b of the second mask 23 is formed so that the inner periphery 23 i of the outer mask region E ₂₂ is located inside the outer periphery 3 e of the insulating film 3. That is, in the second embodiment, the second mask 23 corresponds to the overlapping region P ₃ existing between the first photomask region P ₁ and the external photomask region P ₂₂ in the second photomask 22. The outer peripheral portion covering region E _{3 on} the upper surface of the upper electrode film 4 having a convex pattern is formed by the external mask 23b.

  Next, referring to FIGS. 3K, 3L, and 4C, the upper electrode film 4 and the lower electrode film 2 are patterned by etching 20e using the second mask 23 (second etching). Process).

Here, the outer periphery 4 e of the upper electrode film 4 is defined by the internal mask region E ₂₁ of the internal mask 23 a in the second mask 23. More specifically, the outer periphery 4e of the upper electrode film 4 is patterned along the outer periphery 23 of the internal mask 23a. The pattern of the internal mask region E ₂₁ corresponds to the pattern of the internal photomask region P ₂₁ of the internal photomask 22 a in the second photomask 22.

The outer periphery 2 e of the lower electrode film 2 is defined by the external mask region E ₂₂ of the external mask 23 b in the second mask 23. More specifically, the outer periphery 2e of the lower electrode film 2 is patterned along the outer periphery 23f of the external mask 23b. The pattern of the external mask region E ₂₂ corresponds to the pattern of the external photomask region P ₂₂ of the external photomask 22 b in the second photomask 22.

Therefore, the second photomask 22, internal photomask region P ₂₁ is defines the periphery 4e of the upper electrode film 4, an external photomask region P ₂₂ is a lower electrode film on the external photomask 22b therein photomask 22a 2 outer periphery 2e is defined.

In the second embodiment, since the inner periphery 23i of the outer mask area P ₂₂ of the second mask 23 is located inside the outer periphery 3e of the insulating film 3, the outer peripheral portion covering the external electrode film 4 by an external mask 23b insulating film 3 immediately below the region E ₃ is not etched, on the outer peripheral portion of the insulating film 3 (in the vicinity of the outer periphery 3e), it remains as the remaining electrode film 4r.

  Next, referring to FIGS. 1L and 1M, the second mask 23 is removed from the upper electrode film 4 and the lower electrode film 2, and the upper electrode film 4 and the lower electrode film 2 are patterned (second). Patterning) is completed (second mask removal step).

  In this way, the lower electrode film 2 having the outer periphery 2e is formed on the substrate 1, and the insulating film 3 having the outer periphery 3e positioned on the inner side of the outer periphery 2e is formed on the lower electrode film 2. Thus, a thin film device is obtained in which the upper electrode film 4 having the outer periphery 4e located inside the outer periphery 3e is formed. That is, a thin film device is obtained in which the lower electrode film 2, the insulating film 3, and the upper electrode film 4 are formed on the substrate 1 so that the outer circumferences thereof are stepwise reduced.

  As described above, the remaining electrode film 4r remains on the outer peripheral portion of the insulating film 3, but is separated from the upper electrode film 4, so that the upper electrode film 4 and the remaining electrode film 4r are electrically connected to each other. Therefore, there is no problem as a thin film device.

Therefore, in the second embodiment, since the overlapping region P ₃ exists between the first photomask region P ₁ and the external photomask region P ₂₂ in the second photomask 22, the first photomask 12 Even if a misalignment with the second photomask 22 occurs, if the misalignment is within the overlap region P ₃ , the upper electrode film in the second patterning step. When patterning 4 and the lower electrode film 2, it is possible to prevent the lower electrode film 2 in the vicinity of the outer periphery 3e of the insulating film 3 from being etched by mistake.

  According to the manufacturing method of the second embodiment, a stable thin film device with good insulation and high characteristics can be obtained with good yield between the upper electrode film 4 and the lower electrode film 2. In addition, since the thin film device can be obtained with a high yield by one continuous three film forming process and two film patterning processes by the manufacturing method of Embodiment 2, the manufacturing cost of the thin film device can be further reduced. .

  Also in the manufacturing method of the second embodiment, as in the manufacturing method of the first embodiment, in the step of patterning the upper electrode film 4 and the lower electrode film 2 in the second patterning step by etching, all of the upper electrode film 4 is formed. The time required for etching the film thickness (the time required for etching the entire film thickness, hereinafter the same) is preferably longer than the time required for etching the entire film thickness of the lower electrode film 2.

(Embodiment 3)
Still another embodiment of the thin film device manufacturing method according to the present invention is described with reference to the schematic cross-sectional view of FIG. 6 and the schematic top view of FIG. A step of sequentially forming the electrode film 4 (see FIG. 6A) and a first patterning step of patterning the upper electrode film 4 and the insulating film 3 using the first mask 13 (FIG. 6B to FIG. 6). (See (d)), and a step of forming a conductive film 31 so as to cover the upper electrode film 4 and the insulating film 3 and the lower electrode film 2 patterned in the first patterning step (FIG. 6E), 7 (1)) and the outer periphery of the insulating film 3 on the upper surface of the convex pattern formed on the surface of the conductive film 31 by covering the upper electrode film 4 and the insulating film 3 patterned by the first patterning step. The part inside 3e and A second patterning process for patterning the upper electrode film 4 and the lower electrode film 2 so as to be electrically isolated from each other using the second mask 23 formed separately from at least the side surface portion (FIG. 6). (F) to (h), see FIGS. 7 (2) to (4)).

  That is, the manufacturing method of the third embodiment is the same as the manufacturing method of the first or second embodiment, but the upper electrode and the insulating film patterned by the first patterning step between the first patterning step and the second patterning step. And a step of forming a conductive film so as to cover the lower electrode film, and the second mask is formed on the surface of the conductive film by covering the upper electrode film and the insulating film patterned by the first patterning step. It can be understood that the manufacturing method is characterized in that the upper surface of the convex pattern is formed separately from the outer periphery of the insulating film and at least the side surface. 6 and 7 do not describe a step of forming a mask using a photomask, but it is a preferable method to use a photomask to form a mask as in the first and second embodiments. .

  According to the manufacturing method of the third embodiment, the conductive film 31 can be laminated on each of the upper electrode film 4 and the lower electrode film 2, and by increasing the film thickness of the upper electrode film 4 and the lower electrode film 2. The electrical resistance of the electrode film of the thin film device can be reduced and the mechanical strength can be increased.

  The manufacturing method of the thin film device of Embodiment 3 will be specifically described. Also in this embodiment, it is preferable to form a mask using a photomask as described above. However, since this method is the same as that in Embodiments 1 and 2, description thereof is omitted.

  First, referring to FIG. 6A, similarly to the first or second embodiment, a lower electrode film 2, an insulating film 3, and an upper electrode film 4 are sequentially formed on a substrate 1 (lower electrode film, insulating film). Step of forming the film and the upper electrode film).

  Next, referring to FIGS. 6B to 6D, as the first patterning step, the first etching step (FIGS. 6B and 6C) is performed in the same manner as in the first or second embodiment. Then, by performing the first mask removing step (FIG. 6D), the upper electrode film 4 and the insulating film 3 are patterned by the etching 10e using the first mask 13.

  Next, referring to FIGS. 6E and 7A, a conductive film 31 is formed so as to cover the upper electrode 4, the insulating film 3, and the lower electrode film 2 patterned by the first patterning step. (Conductive film forming step). Although there is no restriction | limiting in particular as an electrically conductive film, From a viewpoint of reducing the electrical resistance of an electrode film and raising mechanical strength, Au film | membrane, Ag film | membrane, Cu film | membrane, Ni film | membrane, etc. are preferable. By appropriately selecting the material of the conductive film, the wettability of a conductive paste or the like can be improved or wire bonding can be easily performed in the extraction electrode forming process described later. For example, when an Au film, an Ag film, or the like is selected as the conductive film, the wettability is higher than that of the upper electrode film and the lower electrode film formed of a Pt film or the like, and when the Au film is selected, the wire bonding is facilitated. The method for forming the conductive film is not particularly limited, but a sputtering method, a vacuum evaporation method, or the like is preferable from the viewpoint that the film thickness accuracy is high and a dense film can be obtained without damage.

  Next, referring to FIGS. 6 (f) and 6 (g) and FIGS. 7 (2) and (3), similarly to the second embodiment, patterning is performed by the first patterning process using the second photomask. By covering the upper electrode film 4 and the insulating film 3 formed, the upper surface of the convex pattern generated on the surface of the conductive film 31 is formed to be separated into a part inside the outer periphery 3e of the insulating film 3 and at least a side part. Using the second mask 23, the upper electrode film 4 and the lower electrode film 2 are patterned by etching 20e (second etching step).

Here, the second mask 23 is inside the outer periphery 3e of the insulating film 3 on the upper surface of the convex pattern generated on the surface of the conductive film 31 by covering the upper electrode film 4 and the insulating film 3 which are separated from each other. The inner mask 23 a having the inner mask region E ₂₁ formed in the portion and the upper electrode film 4 and the insulating film 3 are formed so as to be formed on at least the side portion of the convex pattern generated on the surface of the conductive film 31. and it is constituted by an external mask 23b having an outer mask area E _22. Here, the outer mask 23 b of the second mask 23 is formed so that the inner periphery 23 i of the outer mask region E ₂₂ is inside the outer periphery 3 e of the insulating film 3.

Here, the outer periphery 4 e of the upper electrode film 4 is defined by the internal mask region E ₂₁ of the internal mask 23 a in the second mask 23. More specifically, the outer periphery 4e of the upper electrode film 4 is patterned along the outer periphery 23 of the internal mask 23a.

The outer periphery 2 e of the lower electrode film 2 is defined by the external mask region E ₂₂ of the external mask 23 b in the second mask 23. More specifically, the outer periphery 2e of the lower electrode film 2 is patterned along the outer periphery 23f of the external mask 23b.

In the third embodiment, since the inner periphery 23i of the outer mask area P ₂₂ of the second mask 23 is located inside the outer periphery 3e of the insulating film 3, the outer peripheral portion covering the external electrode film 4 by an external mask 23b conductive film 31 and the upper electrode film 4 immediately under the region E ₃ is not etched, on the outer peripheral portion of the insulating film 3 (in the vicinity of the outer periphery 3e), it remains as each conductive film 31 and the remaining electrode film 4r. Therefore, on the upper electrode film 4 is held conductive film 31, the outer mask area E ₂₂ on the lower electrode film 3 is held conductive film 31 connects the remaining electrode film 4r electrically.

  6H, the second mask 23 is removed from the upper electrode film 4 and the lower electrode film 2, and patterning (second patterning) of the upper electrode film 4 and the lower electrode film 2 is performed. Completion (second mask removal step).

  In this way, the lower electrode film 2 having the outer periphery 2e is formed on the substrate 1, and the insulating film 3 having the outer periphery 3e positioned on the inner side of the outer periphery 2e is formed on the lower electrode film 2. Thus, a thin film device is obtained in which the upper electrode film 4 having the outer periphery 4e located inside the outer periphery 3e is formed. That is, a thin film device is obtained in which the lower electrode film 2, the insulating film 3, and the upper electrode film 4 are formed on the substrate 1 so that the outer circumferences thereof are stepwise reduced.

  Here, in the thin film device of the third embodiment, the conductive film 31 and the remaining conductive film 31r are laminated on the outer periphery of the upper electrode film 4 and the lower electrode film 2, respectively, and the electrical resistance of the electrode film is reduced. Increases mechanical strength. Although the remaining electrode film 4r is electrically connected to the lower electrode film via the conductive film 31, the remaining electrode film 4r and the upper electrode film 4 are electrically separated, and thus have a problem as a thin film device. There is no.

  According to the manufacturing method of the third embodiment, a stable thin film device with good insulation and high characteristics can be obtained with good yield between the upper electrode film 4 and the lower electrode film 2. In addition, since the thin film device can be obtained with a high yield by one continuous three film forming process and two film patterning processes by the manufacturing method of Embodiment 2, the manufacturing cost of the thin film device can be further reduced. .

  Also in the manufacturing method of the third embodiment, as in the manufacturing method of the first embodiment, in the step of patterning the upper electrode film 4 and the lower electrode film 2 in the second patterning step by etching, all of the upper electrode film 4 is formed. The time required for etching the film thickness (the time required for etching the entire film thickness, hereinafter the same) is preferably longer than the time required for etching the entire film thickness of the lower electrode film 2.

(Embodiment 4)
Still another embodiment of the method for manufacturing a thin film device according to the present invention is a manufacturing method in which a post-process is further added to the method for manufacturing a thin film device according to Embodiment 2 with reference to the schematic cross-sectional view of FIG. FIG. 8 shows a post-process using the thin film device obtained in the second embodiment. However, in the manufacturing method of the fourth embodiment, the thin film device obtained in the first or third embodiment may be used. Is preferred.

  The manufacturing method of the thin film device of Embodiment 4 will be specifically described. First, referring to FIGS. 8A and 8B, a thin film device is formed in the same manner as in the second embodiment (steps of forming a lower electrode film, an insulating film, and an upper electrode film, first and second steps, Patterning step).

Next, referring to FIG. 8C, an insulating protective film 41 for preventing a short circuit between the upper electrode film 4 and the lower electrode film 2 is formed on the thin film device of FIG. 8B. (Insulating protective film forming step). The material for forming the insulating protective film 41 is not particularly limited as long as the purpose is achieved, and an inorganic material such as SiN _x , SiO _x , TiO ₂ , and Al ₂ O ₃ , and an organic material such as polyimide are preferably used. It is done. The method for forming the insulating protective film 41 is not particularly limited, and a CVD (chemical vapor deposition) method, a spin coating method, or the like is possible.

  Next, referring to FIG. 8D, an extraction electrode 43u electrically connected to the upper electrode film 4 and an extraction electrode 43d electrically connected to the lower electrode film are formed (extraction electrode forming step). The material for forming the extraction electrodes 43d and 43u is not particularly limited as long as the purpose is achieved, and an Al film, an Ag film, a Cu / Ti film, or the like is preferably used. Here, the Cu / Ti film refers to a film in which a Ti film and a Cu film are laminated in this order from the bottom. For example, a Cu film having a thickness of 0.5 μm is formed on a Ti film having a thickness of 0.05 μm. . If necessary, a Ni film, an Au film, or the like may be formed as the uppermost layer film of the extraction electrode. The formation method of the extraction electrodes 43d and 43u is not particularly limited, and a sputtering method, a plating method, a printing method, an electron beam evaporation method, or the like is possible.

  Further, referring to FIG. 8 (e), mechanical protection and short-circuiting of the extraction electrode 43u electrically connected to the upper electrode film 4 and the extraction electrode 43d electrically connected to the lower electrode film (as required) An insulating protective film 44 for preventing a short circuit), a solder bump 45u electrically connected to the extraction electrode 43u electrically connected to the upper electrode film 4, and an extraction electrode electrically connected to the lower electrode film 2 Solder bumps 45d electrically connected to 43d are formed (solder pump forming step). Note that, instead of the solder bumps 45u and 45d, it may be electrically connected to an external circuit by wire bonding or the like.

Thus, a thin film device suitable for the mode of use can be manufactured.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic cross section which shows one Embodiment of the manufacturing method of the thin film device concerning this invention. Here, (a) is a step of forming a lower electrode film, an insulating film and an upper electrode film, (b) is a step of forming a first photoresist layer, (c) is an exposure step of the first photoresist layer, d) is a first mask forming step, (e) and (f) are first etching steps, (g) is a first mask removing step, and (h) is a second photoresist layer forming step. , (I) is the second photoresist layer exposure step, (j) is the second mask formation step, (k) and (l) are the second etching step, and (m) is the second mask step. A removal process is shown. It is a schematic top view which partially shows one Embodiment of the manufacturing method of the thin film device concerning this invention. Here, (1) to (4) are schematic top views corresponding to FIGS. 1 (f), (j), (l) and (m), respectively. It is a schematic cross section which shows other embodiment of the manufacturing method of the thin film device concerning this invention. Here, (a) is a step of forming a lower electrode film, an insulating film and an upper electrode film, (b) is a step of forming a first photoresist layer, (c) is an exposure step of the first photoresist layer, d) is a first mask forming step, (e) and (f) are first etching steps, (g) is a first mask removing step, and (h) is a second photoresist layer forming step. , (I) is the second photoresist layer exposure step, (j) is the second mask formation step, (k) and (l) are the second etching step, and (m) is the second mask step. A removal process is shown. It is a schematic top view which partially shows other embodiment of the manufacturing method of the thin film device concerning this invention. Here, (1) to (4) are schematic top views corresponding to FIGS. 3 (f), (j), (l) and (m), respectively. It is a schematic diagram which shows the planar layout of the 1st photomask and 2nd photomask which are used in other embodiment of the manufacturing method of the thin film device concerning this invention. Here, (a) is a schematic bottom view showing the first photomask, (b) is a schematic bottom view showing the second photomask, (c) is a schematic cross-sectional view at VC-VC in (a), ( d) shows a schematic cross-sectional view in VD-VD of (b). It is a schematic cross section which shows other embodiment of the manufacturing method of the thin film device concerning this invention. Here, (a) is a process of forming a lower electrode film, an insulating film and an upper electrode film, (b) and (c) are a first etching process using a first mask, and (d) is a first mask. (E) shows a conductive film formation step, (f) and (g) show a second etching step using the second mask, and (h) show a second mask removal step. It is a schematic top view which partially shows further another embodiment of the manufacturing method of the thin film device concerning this invention. Here, (1) to (4) are schematic top views corresponding to FIGS. 6 (e) to (h), respectively. It is a schematic cross section which shows other embodiment of the manufacturing method of the thin film device concerning this invention. Here, (a) is a process for forming a lower electrode film, an insulating film and an upper electrode film, (b) is a first and second patterning process, (c) is a process for forming an insulating protective film, and (d) is a drawer. Electrode forming step, (e) shows a solder bump forming step. It is a schematic cross section which shows an example of the conventional manufacturing method of a thin film device. Here, (a) is a lower electrode film forming step, (b) is a lower electrode film patterning step, (c) is an insulating film forming step, (d) is an insulating film patterning step, and (e) is an upper portion. An electrode film formation and patterning process are shown. It is a schematic cross section which shows the other example of the conventional manufacturing method of a thin film device. Here, (a) is a method in which the upper electrode film, the insulating film, and the lower electrode film are continuously etched almost vertically and is patterned once, and (b) is a taper of the upper electrode film, the insulating film, and the lower electrode film. (C) shows a method in which the upper electrode film and the insulating film are continuously etched, and then the lower electrode film is etched and patterned twice.

Explanation of symbols

1 substrate, 2 lower electrode film, 2e, 3e, 4e, 12e, 13e, 22e, 22f, 23e, 23f outer periphery, 3 insulating film, 4 upper electrode film, 4r remaining electrode film, 10d, 20d exposure, 10e, 20e etching , 11 First photoresist layer, 12 First photomask, 13 First mask, 21 Second photoresist layer, 22 Second photomask, 22a Internal photomask, 22b External photomask, 22i, 23i Inner circumference, 23 second mask, 23a inner mask, 23b outer mask, 31 conductive film, 31r remaining conductive film, 41, 44 insulating protective film, 43d, 43u extraction electrode, 45d, 45u solder bump, 120, 220 transparent substrate, E ₁ first mask region, E ₂₁ internal mask region, E ₂₂ external mask region, E ₃ outer periphery covering region, P ₁ first photomask Disk region, P ₂₁ internal photomask region, P ₂₂ external photomask region, P ₃ overlap region.

Claims (5)

A step of sequentially forming a lower electrode film, an insulating film and an upper electrode film on the substrate;
A first patterning step of patterning the upper electrode film and the insulating film using a first mask;
The second electrode is formed separately on the upper surface of the convex pattern based on the upper electrode film and the insulating film patterned by the first patterning step and on the inner side of the outer periphery of the insulating film and at least the side surface part. And a second patterning step of patterning the upper electrode film and the lower electrode film so as to be electrically separated from each other using the mask.   2. The method of manufacturing a thin film device according to claim 1, wherein an external mask formed on at least the side surface of the second mask covers an outer peripheral portion of an upper surface of the convex pattern. In the first patterning step, a first photomask is used to form the first mask, and the first photomask has a first photomask region that defines an outer periphery of the insulating film. ,
In the second patterning process, a second photomask is used to form the second mask, and the second photomask is an internal photomask that defines the outer periphery of the upper electrode film, which are separated from each other. An internal photomask having a region and an external photomask having an external photomask region defining an outer periphery of the lower electrode film;
2. The planar layout of the first photomask and the second photomask, wherein the first photomask region and the external photomask region partially overlap each other. The manufacturing method of the thin film device of 2.   The second patterning step includes a step of patterning the upper electrode film and the lower electrode film by etching, and the total film thickness etching time for the upper electrode film is equal to or longer than the total film thickness etching time for the lower electrode film. The method for manufacturing a thin film device according to any one of claims 1 to 3, wherein: A conductive film is formed between the first patterning step and the second patterning step so as to cover the upper electrode, the insulating film, and the lower electrode film patterned by the first patterning step. Further comprising a step,
The second mask is inside the outer periphery of the insulating film on the upper surface of the convex pattern generated on the surface of the conductive film by covering the upper electrode film and the insulating film patterned by the first patterning step. 5. The method of manufacturing a thin film device according to claim 1, wherein the thin film device is separated into at least a side surface portion and a side surface portion.

Images