JP2010091350A - Method of manufacturing mems sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance detection accuracy of a physical quantity by a MEMS sensor. <P>SOLUTION: A method of manufacturing the MEMS sensor including a support part, a beam part having one end coupled to the support part and thinner than the support part, a weight part coupled to the other end of the beam part and thicker than the beam part, and a strain detection means provided at the beam part and detecting the strain of the beam part includes the steps of: forming a laminate structure including the strain detection means including films made by laminating the films on a surface of a substrate and the substrate; forming a first protective film having a first through-hole formed therein on a thin film of the laminate structure; etching the laminate structure exposed from the first through-hole so that the laminate structure is penetrated, thereby forming a side surface of the beam part and a part of a side surface of the weight part separated from the beam part; forming a second protective film which covers the part of the side surface of the weight part separated from the beam part on the back surface of the substrate and which includes a second through-hole formed therein; and etching the substrate exposed from the second through-hole, thereby adjusting the thickness of the beam part and forming the residual part of the side surface of the weight part made of the substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

2. Description of the Related Art Conventionally, MEMS sensors that detect acceleration, posture (inclination angle), angular velocity, vibration, and the like by detecting deformation of a beam portion caused by an inertial force acting on a weight portion with a piezoresistive element or the like are known. In such a MEMS sensor, since the force acting on the beam portion from the weight portion deforms the beam portion according to the force acting on the weight portion, the detection accuracy of physical quantities such as acceleration, posture (tilt angle), angular velocity, amplitude, etc. Depends on the alignment accuracy between the weight portion and the beam portion.
Patent Documents 1 and 2 describe a method of manufacturing a MEMS sensor in which a weight portion and a beam portion are formed by etching from both front and back sides of a substrate.
Patent Document 3 describes a method of manufacturing a MEMS sensor in which a beam part and a weight part are formed by welding a low melting point metal body to the beam part.
JP 2007-61956 A Japanese Patent Laying-Open No. 2005-61840 Japanese Patent Laid-Open No. 9-80070

  However, in the manufacturing methods described in Patent Documents 1 and 2, since the shapes of the weight portion and the beam portion are formed by etching from both the front and back sides of the substrate, the position of the protective film used when etching from both the front and back sides is formed. The positions of the weight part and the beam part shift due to the deviation. Moreover, in the manufacturing method described in Patent Document 3, the accuracy of mechanically aligning the low melting point metal body with the beam portion is a problem, and it is difficult to increase the alignment accuracy of the weight portion and the beam portion. , Manufacturing costs increase due to mechanical sequential processing.

  The present invention was created in view of these problems, and an object of the present invention is to improve the detection accuracy of a physical quantity by a MEMS sensor.

  (1) A MEMS sensor manufacturing method for achieving the above object includes a support part, a beam part having one end coupled to the support part and thinner than the support part, and a beam part coupled to the other end of the beam part and thicker than the beam part. A method for manufacturing a MEMS sensor, comprising: a weight portion; and a strain detection means provided on the beam portion for detecting strain of the beam portion, wherein the strain detection is configured by a film by laminating a film on the surface of the substrate. Forming a laminated structure including means and a substrate, forming a first protective film having a first through-hole formed on a thin film of the laminated structure, and exposing the first through-hole By etching until the structure is penetrated, the side surface of the beam portion and the portion spaced from the beam portion on the side surface of the weight portion are formed, and the portion separated from the beam portion on the side surface of the weight portion is covered. Forming a second protective film having a second through hole on the back surface of the substrate; The substrate exposed to form the remainder consisting of the substrate side of the weight portion with adjusting the thickness of the beam portion by etching from involves.

  According to the present invention, by etching using the first protective film formed on the thin film of the laminated structure, the side surface of the beam portion and the whole or a part of the side surface of the portion separated from the beam portion of the side surface of the weight portion are determined. Therefore, the alignment accuracy between the weight portion and the beam portion can be increased. Therefore, according to the present invention, the physical quantity detection accuracy by the MEMS sensor can be increased. Note that the side surface of the beam portion and the side surface of the weight portion are surfaces perpendicular to the main surface of the substrate.

  (2) In the manufacturing method of the MEMS sensor for achieving the above object, two layers are bonded to both sides of the weight portion by etching until the laminated structure exposed from the first through hole is penetrated. It may also include forming a portion that includes a side surface of the four beam portions parallel to each other and a side surface of the weight portion that is parallel to the side surface of the beam portion and that is separated from the beam portion.

  In a MEMS sensor that includes four beam portions that are coupled two on both sides of the weight portion and that are parallel to each other in the longitudinal direction, and detects a physical quantity of three-dimensional motion by detecting distortion of each beam portion, The dimensional accuracy of the weight in the hand direction greatly affects the accuracy of physical quantity detection by the MEMS sensor. According to the present invention, since the portion of the side surface of the weight portion parallel to the side surface of the beam portion is determined by the pattern of the first protective film, the dimensional accuracy of the weight portion in the short direction of the beam portion is increased.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, 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)
FIG. 1 shows a piezoresistive acceleration sensor which is a MEMS sensor manufactured according to the first embodiment of the present invention. The acceleration sensor 1 is a MEMS sensor for detecting three-axis acceleration components orthogonal to each other.

  The acceleration sensor 1 includes a support portion S having a rectangular frame shape, cantilevered beam portions F1, F2, F3, and F4 having one end coupled to the support portion S, and beam portions F1, F2, F3, and F4. And a piezoresistive element 40 as strain detecting means, which are accommodated in a package (not shown). These structural elements and electrical functional elements constituting the acceleration sensor 1 include a laminated structure in which a substrate 100 made of a plate-like bulk material, a silicon layer 104, an insulating layer 106, and a wiring layer 108 are integrally joined. It is composed by the body.

  The support portion S is a structural element for supporting the beam portions F1, F2, F3, and F4. The form of the support part S is designed according to the form and arrangement of the beam parts F1, F2, F3, F4 and the form and arrangement of the weight part M. The support part S includes a substrate 100, a silicon layer 104, and an insulating layer 106. The support portion S is a multilayer structure including a substrate 100 that is sufficiently thicker than the beam portions F1, F2, F3, and F4. Therefore, the support portion S is not substantially deformed.

  One end of each of the beam portions F1, F2, F3, and F4 having the same form is coupled to the support portion S. The beam portions F1, F2, F3, and F4 and the support portion S are separated by a slit H1 that is a through hole, and the beam portions F1, F2, F3, and F4 and the weight portion M are separated by a slit H2 that is a through hole. Yes. The beam portions F1 and F2 are arranged in series in parallel with the longitudinal direction of the support portion S and the weight portion M with the weight portion M interposed therebetween. The beam portions F3 and F4 are arranged in series in parallel with the longitudinal direction of the support portion S and the weight portion M with the weight portion M interposed therebetween. The other ends of the beam portions F1 and F3 are coupled to one side surface of the weight portion M, and the other ends of the beam portions F2 and F4 are coupled to the other side surface of the weight portion M. The beam portions F 1, F 2, F 3, and F 4 are composed of the silicon layer 104 and the insulating layer 106.

  The weight portion M has a columnar shape having a cross-shaped bottom surface, and has a form in which the center of gravity is located away from the surface in contact with the beam portions F1, F2, F3, and F4. The weight portion M is long in the longitudinal direction of the beam portions F1, F2, F3, and F4 and short in the short direction of the beam portions F1, F2, F3, and F4. The side surface of the weight portion M includes a portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 and a remaining portion perpendicular to the side surfaces of the beam portions F1, F2, F3, and F4. The weight portion M includes a substrate 100 that is sufficiently thicker than the beam portions F1, F2, F3, and F4. Therefore, the weight part M behaves as a rigid body that moves relative to the support part S.

  A total of twelve piezoresistive elements 40 are provided in the proximity region of the beam portions F1, F2, F3, and F4 to the support portion S and the proximity region of the weight portion M. The piezoresistive element 40 includes a resistance portion 42 having a relatively low impurity concentration and a connection resistance reducing portion 41 having a high impurity concentration. All of these piezoresistive elements 40 straddle the boundary between the beam portions F1, F2, F3, F4 and the support portion S or the boundary between the beam portions F1, F2, F3, F4 and the weight portion M. The piezoresistive element 40 is formed in the silicon layer 104. The direction of the stress generated by the deformation of the beam portions F1, F2, F3, and F4 is reversed between the front surface and the back surface of the beam portions F1, F2, F3, and F4. For this reason, the piezoresistive element 40 is thinly formed near the interface of the silicon layer 104. The piezoresistive elements 40 form a bridge circuit with a set of four, and are wired so that output signals corresponding to three-axis acceleration components orthogonal to each other can be extracted from each bridge circuit. A portion where the line width of the wiring layer 108 constituting a part of the wiring for connecting the piezoresistive element 40 as a bridge circuit is narrowed is omitted in FIG. 1A.

(Production method)
Next, a method for manufacturing the acceleration sensor 1 will be described with reference to FIGS.
First, the laminated structure W shown in FIG. 2 in which a three-dimensional mechanical structure is not formed is formed by a known method in which a thin film is laminated, modified, or etched on the surface of the substrate 100. For example, the surface of a base wafer made of single crystal silicon (Si) having a thickness of 400 to 625 μm is thermally oxidized to form an etch stopper layer 102 made of silicon dioxide (SiO ₂ ) and having a thickness of 1 μm, and the remaining portion is thick. A substrate 100 composed of a silicon layer 101 and an etch stopper layer 102 is formed. Here, the substrate 100 is made of a plate-shaped bulk material that is sufficiently thick with respect to the thin film laminated on the surface of the substrate 100 and has a thickness that almost controls the rigidity of the support portion S and the weight portion M. That's fine. Then, the laminated structure W shown in FIG. 2 is formed by processing performed from the surface side which is one of the two main surfaces of the substrate 100. For example, a bond wafer made of single crystal silicon and forming a thin silicon layer 104 having a thickness of 5 to 20 μm is bonded to the etch stopper layer 102 of the substrate 100 to obtain an SOI (Silicon On Insulator) wafer. Next, impurity ions are implanted from the surface of the thin silicon layer 104 and activated to form the piezoresistive element 40 in the silicon layer 104. Next, as the insulating layer 106, for example, a film of 1 μm thick silicon dioxide, silicon nitride (SiN) or the like is formed on the surface of the silicon layer 104 by a thermal oxidation method or a deposition method. Next, a wiring layer 108 made of aluminum (Al), copper (Cu), AlSi or the like is formed on the surface of the insulating layer 106, and the wiring layer 108 and the piezoresistive element 40 are connected through a contact hole.

  Next, as shown in FIGS. 3A, 3B, and 3C, a first protective film R1 is formed on the surface of the film laminated on the substrate 100 of the laminated structure W. The first protective film R1 is made of a photoresist that is a photosensitive resin, and is formed with slits RS that are first through holes for forming the slits H1 and H2 that are the through holes shown in FIG. . The thickness of the first protective film R1 is 2 μm, for example.

Subsequently, as shown in FIGS. 3A, 3B, and 3C, etching is performed until the laminated structure W exposed from the slit RS of the first protective film R1 is penetrated. As a result, all the side surfaces of the beam portions F1, F2, F3, and F4 shown in FIG. 1 and portions spaced from the beam portions F1, F2, F3, and F4 on the side surface of the weight portion M are formed. At this time, a portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 on the side surface of the weight portion M is formed. Specifically, for example, the insulating layer 106 made of silicon dioxide is etched by reactive ion etching using CHF ₃ gas. Subsequently, the thin silicon layer 104 made of single crystal silicon is etched by reactive ion etching using CF ₄ gas. Subsequently, the etch stopper layer 102 made of silicon dioxide on the substrate 100 is etched by reactive ion etching (RIE) using CHF ₃ gas. Subsequently, the thick silicon layer 101 of the substrate 100 is etched by Deep-RIE (Reactive Ion Etching), which is a Bosch process in which passivation using C ₄ F ₈ plasma and etching using SF ₆ plasma are alternately repeated at short intervals. .

  Next, after removing the first protective film R1, the laminated structure W is temporarily bonded to the sacrificial substrate 99, and on the surface of the substrate 100 of the laminated structure W, as shown in FIGS. 4A, 4B, and 4E. A second protective film R2 is formed. The sacrificial substrate 99 and the laminated structure W can be temporarily bonded using the bonding means B made of wax, photoresist, double-sided pressure-sensitive adhesive sheet, or the like. The second protective film R2 is made of a photoresist that is a photosensitive resin, and second through holes RT for adjusting the thickness of the beam portions F1, F2, F3, and F4 by etching are formed by photolithography. ing. The thickness of the second protective film R2 is 6 μm, for example.

  As shown in FIG. 4C and FIG. 4E, the second protective film R2 is dimensioned to cover the part of the weight M formed by the first protective film R1 that is separated from the beam parts F1, F2, F3, F4. Form. That is, regarding the portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 among the portions spaced from the beam portions F1, F2, F3, and F4 of the weight portion M formed by the first protective film R1, The width of the portion of the second protective film R2 that covers the portions of the weight M that are separated from the beam portions F1, F2, F3, and F4 so that the portion Mt is covered as shown in FIG. 4B and 4C is the width of the portion of the weight M that is separated from the beam portions F1, F2, F3, and F4 (the length of the beam portion in the short direction). ) Wider than. On the other hand, of the portions spaced from the beam portions F1, F2, F3, and F4 of the weight portion M formed by the first protective film R1, the portion perpendicular to the side surfaces of the beam portions F1, F2, F3, and F4 Is completely covered by the second protective film R2 as shown in FIG. 4E.

As shown in FIG. 4C, the width D2 of the second protective film R2 that protrudes from the portion of the weight M away from the beams F1, F2, F3, and F4 in the short direction of the beam is equal to the weight M. Is set to be narrower than the width L2 of the slit H2 separating the beam portions F1, F2, F3, and F4. That is, portions of the substrate 100 that overlap the beam portions F1, F2, F3, and F4 are completely exposed from the opening RT of the second protective film R2. Further, the width D2 of the second protective film R2 that protrudes from the portion of the weight M that is separated from the beam parts F1, F2, F3, and F4 is larger than the alignment tolerance EY of the second protective film R2 shown in FIG. 4D. Set. More specifically, the width D2 of the second protective film R2 that protrudes from the portion of the weight M that is separated from the beam portions F1, F2, F3, and F4 is set to a range that satisfies the following expression.
EY <D2 <L2-EY

  The width L2 of the slit H2 that separates the weight part M and the beam parts F1, F2, F3, and F4 can be set to, for example, about 50 μm to 100 μm, and the alignment tolerance EY of the protective film R2 in the photolithography technique is about 2 μm. Can be within the range. Therefore, the width D2 of the second protective film R2 protruding from the part of the weight M that is spaced from the beam parts F1, F2, F3, F4 is set larger than the alignment tolerance EY of the second protective film R2, and It is very easy to set narrower than the width L2 of the slit H2 that separates the weight portion M and the beam portions F1, F2, F3, and F4. That is, even in the case where the misalignment of the second protective film R2 is the maximum, as shown in FIG. 4D, the beam portion among the portions of the weight portion M that are separated from the beam portions F1, F2, F3, and F4. A portion Mt parallel to the side surfaces of F1, F2, F3, and F4 is covered with the second protective film R2, and a portion that overlaps the beam portions F1, F2, F3, and F4 of the substrate 100 is completely exposed from the opening RT. It is sufficiently possible and easy to form the second protective film R2.

  As described above, by forming the second protective film R2, the portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 on the side surface of the weight M is determined by the pattern of the first protective film R1. Can be made.

Next, as shown in FIGS. 5A and 5B, by etching the substrate 100 exposed from the second through hole RT of the second protective film R, the beam portions F1, F2, F3 shown in FIG. , F4 is removed. As a result, the thicknesses of the beam portions F1, F2, F3, and F4 shown in FIG. 1 are adjusted, and the remaining portion Ms made of the substrate 100 on the side surface of the weight portion M is formed. As described above, in this step of etching the substrate 100 using the second protective film R2, the portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 on the side surface of the weight portion M is not deformed. Specifically, for example, a part of the thick silicon layer 101 of the substrate 100 is removed by the above-described Bosch process, and a part of the etch stopper layer 102 of the substrate 100 is removed by reactive ion etching (RIE) using CHF ₃ gas. Remove. The etch stopper layer 102 may be etched isotropically with buffered hydrofluoric acid or dilute hydrofluoric acid, or may be isotropically etched in a gas phase using a mixed gas of anhydrous HF and alcohol.

  Thereafter, the second protective film R and the bonding means B are removed, and a process such as dicing is performed to complete the acceleration sensor 1 shown in FIG.

  According to the manufacturing method described above, all the side surfaces of the beam portions F1, F2, F3, and F4 and the side surfaces of the beam portions F1, F2, F3, and F4 on the side surface of the weight portion M are etched by using the first protective film R1. Since the parallel portion Mt is formed, the alignment accuracy between the beam portions F1, F2, F3, and F4 and the weight portion M can be increased. As a result, the shape accuracy of the movable part of the acceleration sensor 1 can be increased. In the acceleration sensor 1 that detects acceleration by detecting distortion of the four beam portions F1, F2, F3, and F4 whose longitudinal directions are parallel to each other, all the side surfaces and the weight portions of the beam portions F1, F2, F3, and F4 The detection accuracy of the acceleration sensor 1 is that the alignment accuracy of the portion Mt parallel to the side surfaces of the beam portions F1, F2, F3, and F4 on the side surface of M is improved by one etching using one protective film R1. It greatly contributes to improvement.

2. Second Embodiment FIGS. 6A, 6B, 6C, and 6D show a six-axis motion sensor that is a MEMS sensor manufactured according to a second embodiment of the present invention. The motion sensor 2 is a die constituting a MEMS sensor for detecting a triaxial acceleration component orthogonal to each other and a triaxial angular velocity component orthogonal to each other.

  The motion sensor 2 includes a support S having a rectangular frame shape, a cantilever beam F having a fixed end coupled to the support S, and a weight M coupled to a free end of the beam F. And a piezoresistive element 40 as a strain detecting means and a piezoelectric element P as a strain detecting means or a driving means, and are accommodated in a package (not shown). These structural elements and electrical functional elements constituting the motion sensor 2 include a substrate 100 made of a plate-like bulk material, a silicon layer 104, an insulating layer 106, a wiring layer 108, a piezoelectric layer 110, an electrode layer 112, and a protection. The layer 114 and the wiring layer 115 are configured by a laminated structure in which the layers 114 and the wiring layer 115 are integrally bonded.

  The support portion S is a frame-shaped structural element for supporting the four beam portions F. The support portion S includes a substrate 100, a thin silicon layer 104, an insulating layer 106, and a protective layer 114. The support portion S is a multilayer structure including the substrate 100 that is sufficiently thicker than the beam portion F. Therefore, the support portion S is not substantially deformed.

  The four beam portions F having the same form are arranged in a cross shape inside the support portion S, and one end of each is coupled to the support portion S and the other end is coupled to the weight portion M. Each beam portion F includes a thin silicon layer 104, an insulating layer 106, and a protective layer 114.

  The weight portion M has a form in which a rectangular parallelepiped portion is coupled to four corners of a substantially rectangular parallelepiped central portion coupled to the beam portion F. The weight portion M includes a substrate 100 that is sufficiently thicker than the beam portion F. Therefore, the weight part M behaves as a rigid body that moves relative to the support part S.

The weight part M, the support part S, and the beam part F are separated by four slits H which are through holes.
A total of twelve piezoresistive elements 40 are provided in a proximity region of the beam portion F with the support portion S and a proximity region with the weight portion M. The piezoresistive element 40 is formed in the silicon layer 104. The direction of the stress generated by the deformation of the beam portion F is reversed between the front surface and the back surface of the beam portion F. For this reason, the piezoresistive element 40 is thinly formed near the interface of the silicon layer 104. The piezoresistive elements 40 form a bridge circuit with a set of four, and are wired so that output signals corresponding to three-axis acceleration components orthogonal to each other can be extracted from each bridge circuit.

  The piezoelectric element P is provided on the surface of the thin silicon layer 104. The piezoelectric element P has a structure in which the piezoelectric layer 110 is sandwiched between the wiring layer 108 functioning as an electrode and the electrode layer 112. A part of the plurality of piezoelectric elements P functions as a driving unit that circulates the weight part M by distorting the beam part F, and the remaining part is a detection unit that detects distortion of the beam part F caused by Coriolis force due to angular velocity. Function as.

(Production method)
A method for manufacturing the motion sensor 2 will be described with reference to FIGS.
First, the laminated structure W shown in FIG. 7 in which a three-dimensional mechanical structure is not formed is formed by a known method of laminating, modifying, or etching a thin film on the surface of the substrate 100. For example, the substrate 100, the thin silicon layer 104, the insulating layer 106 are formed in the same manner as in the first embodiment, the piezoresistive element 40 is formed, and then the wiring layer 108 made of platinum (Pt) having a thickness of 0.1 μm is formed. It is formed over the entire surface of the insulating layer 106. Next, a piezoelectric layer 110 made of PZT (lead zirconate titanate) having a thickness of 3 μm is formed on the entire surface of the wiring layer 108 by a sputtering method or a sol-gel method. Next, an electrode layer 112 made of platinum and having a thickness of 0.1 μm is formed on the entire surface of the piezoelectric layer 110. Thereafter, the electrode layer 112, the piezoelectric layer 110, and the wiring layer 108 are sequentially etched using three kinds of protective films. Next, a protective layer 114 made of photosensitive polyimide and having a thickness of 10 μm is formed, and contact holes are formed by exposure and development. Next, a wiring layer 118 made of aluminum (Al) connected to the wiring layer 108 and the electrode layer 112 exposed from the contact hole is formed. Next, when the wiring layer 118 is patterned by etching, a laminated structure W shown in FIG. 8 is obtained.

  Next, as shown in FIGS. 8A, 8B, and 8C, a first protective film R1 is formed on the surface of the film laminated on the substrate 100 of the laminated structure W. The first protective film R1 is made of a photoresist that is a photosensitive resin, and is formed with slits RS that are first through holes for forming the slits H that are the through holes shown in FIG. The thickness of the first protective film R1 is, for example, 6 μm.

  Subsequently, as in the first embodiment, etching is performed until the laminated structure W exposed from the slit RS of the first protective film R1 is penetrated.

  Next, as shown in FIGS. 9A, 9B, and 9C, the laminated structure W is temporarily bonded to the sacrificial substrate 99 using the bonding means B, and a second protective film is formed on the surface of the substrate 100 of the laminated structure W. R2 is formed. The second protective film R2 is made of a photoresist which is a photosensitive resin, and a second through hole RT for adjusting the thickness of the beam portion F by etching is formed by a photolithography technique. The thickness of the second protective film R2 is 6 μm, for example. Similar to the first embodiment, the shape and size of the second protective film R2 are set so as to cover the portion of the side surface of the weight portion M that is separated from the beam portion F.

  Next, as shown in FIGS. 10A and 10B, the beam portion of the substrate 100 is etched by etching the substrate 100 exposed from the second through hole RT of the second protective film R, as in the first embodiment. The portion overlapping F is removed, the thickness of the beam portion F is adjusted, and the remaining portion Ms made of the substrate 100 on the side surface of the weight portion M is formed. As a result, the beam portion F and the weight portion M shown in FIG. 6 are completed.

  Also in the present embodiment, all the side surfaces of the beam portion F and all or a portion of the side surfaces of the weight portion M spaced apart from the beam portion F are formed by etching using the first protective film R1. The alignment accuracy between the part F and the weight part M can be increased.

3. 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, the materials, dimensions, film forming methods, and pattern transfer methods shown in the above embodiments are merely examples, and descriptions of addition and deletion of processes and replacement of process orders that are obvious to those skilled in the art are omitted. ing. For example, the present invention can also be applied to other MEMS sensors such as vibration sensors.

The top view concerning a first embodiment of the present invention. Sectional drawing corresponding to the BB line shown to FIG. 1A. Sectional drawing corresponding to CC line shown to FIG. 1A. Sectional drawing corresponding to the DD line shown to FIG. 1A. Process sectional drawing corresponding to the BB line shown to FIG. 1A. Process sectional drawing corresponding to the BB line shown to FIG. 1A. Process sectional drawing corresponding to the DD line shown to FIG. 1A. The top view concerning the process corresponding to FIG. 3A and FIG. 3B. Process sectional drawing corresponding to the BB line shown to FIG. 1A. Process sectional drawing corresponding to the DD line shown to FIG. 1A. FIG. 4B is an enlarged view of a 4C portion shown in FIG. 4B. FIG. 4B is an enlarged view of a 4C portion shown in FIG. 4B. The top view concerning the process corresponding to FIG. 4A and 4B. Process sectional drawing corresponding to the BB line shown to FIG. 1A. Process sectional drawing corresponding to the DD line shown to FIG. 1A. The top view concerning 2nd embodiment of the present invention. Sectional drawing corresponding to the BB line shown to FIG. 6A. Sectional drawing corresponding to CC line shown to FIG. 6A. The bottom view concerning a second embodiment of the present invention. Process sectional drawing corresponding to the BB line shown to FIG. 6A. Process sectional drawing corresponding to the BB line shown to FIG. 6A. Process sectional drawing corresponding to CC line shown to FIG. 6A. The top view concerning the process corresponding to FIG. 6A and FIG. 6B. Process sectional drawing corresponding to the BB line shown to FIG. 6A. Process sectional drawing corresponding to CC line shown to FIG. 6A. The top view concerning the process corresponding to FIG. 9A and FIG. 9B. Process sectional drawing corresponding to the BB line shown to FIG. 6A. Process sectional drawing corresponding to CC line shown to FIG. 6A.

Explanation of symbols

1: acceleration sensor, 2: motion sensor, 40: piezoresistive element, 41: connection resistance reducing unit, 42: resistance unit, 99: sacrificial substrate, 100: substrate, 101: silicon layer, 102: etch stopper layer, 104: Silicon layer, 106: insulating layer, 108: wiring layer, 110: piezoelectric layer, 112: electrode layer, 114: protective layer, 115: wiring layer, 118: wiring layer, B: bonding means, F: beam portion, H: Slit, M: weight part, P: piezoelectric element, R1: first protective film, R2: second protective film, RS: slit, RT: through hole, S: support part, W: laminated structure

Claims (2)

A support part;
A beam part having one end coupled to the support part and thinner than the support part;
A weight portion coupled to the other end of the beam portion and thicker than the beam portion;
Strain detection means provided on the beam portion for detecting strain of the beam portion;
A method of manufacturing a MEMS sensor comprising:
By laminating a film on the surface of the substrate, a laminated structure including the strain detecting means constituted by the film and the substrate is formed,
Forming a first protective film having a first through hole on the film of the laminated structure;
Etching until penetrating the laminated structure exposed from the first through hole, thereby forming a side surface of the beam portion and a portion spaced from the beam portion of the side surface of the weight portion,
Forming a second protective film on the back surface of the substrate, covering the portion of the side surface of the weight portion that is separated from the beam portion, and forming a second through hole;
Adjusting the thickness of the beam portion by etching the substrate exposed from the second through-hole and forming the remaining portion of the substrate on the side surface of the weight portion;
A method for manufacturing a MEMS sensor. Etching is performed until the laminated structure exposed from the first through-hole is penetrated, so that two side surfaces of the weight portion parallel to each other and two side surfaces of the weight portion are coupled to each other. Forming a portion that includes a portion parallel to the side surface of the beam portion of the side surface of the weight portion and is spaced apart from the beam portion;
The manufacturing method of the MEMS sensor of Claim 1 including this.

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