JP5298508B2 - Mechanical quantity detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical quantity detecting sensor and its manufacturing method which eliminates faulty wire connections, in the internal wiring of the sensor body of a capacitance-type mechanical quantity detecting sensor for reducing product defects. <P>SOLUTION: The mechanical quantity detection sensor is a capacitance-type mechanical quantity detection sensor. A semiconductor substrate is arranged inside a frame; a support pillar for connecting the upper support substrate and the lower support substrate is provided; and a connecting part made of a conductive material is provided, on at least one of the upper end or lower end of the support pillar, and connects the upper support substrate or the lower support substrate to the support pillar. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a mechanical quantity detection sensor that detects a mechanical quantity using a capacitive element and a manufacturing method thereof, and more particularly, to a sensor of a type that detects acceleration or / and angular velocity.

  In recent years, a type of sensor using a capacitive element (so-called capacitance type sensor) has been put to practical use as an acceleration sensor or an angular velocity sensor having a small and simple structure by using MEMS (Micro Electro Mechanical Systems) technology. Yes. In general, a capacitance type sensor has a weight body that can be displaced with a predetermined degree of freedom in a semiconductor substrate sandwiched between a pair of glass substrates, and the weight body is accompanied by acceleration, angular velocity, or the like. It is used as a weight body for detecting displacement. The displacement is detected based on the capacitance value of the capacitive element (Patent Document 1).

Conventionally, in order to detect a dynamic quantity of multi-axis components in a capacitance type sensor, a plurality of single-axis sensors have been used in combination. However, this is a problem in terms of size and cost. Therefore, research on a capacitive sensor capable of detecting multi-axis components with a single sensor element is in progress. In such a sensor that detects the mechanical quantity of the multi-axis component using one sensor element, the capacitive element is used to detect the dynamic quantity of the multi-axis component or drive the weight body. Wiring connection to the outside is necessary for the electrodes to be configured. In order to perform this wiring connection simply and efficiently, for example, a pair of upper and lower glass substrates are connected in a semiconductor substrate, and a wiring columnar body made of a conductive material is disposed. The structure which takes an electrical connection with metal wiring is disclosed (patent document 2).
JP 2007-057469 A JP 2007-003192 A

  However, when connecting the above-mentioned wiring columnar body and the metal wiring on the glass substrate at the time of joining the glass substrate and the semiconductor substrate, ohmic contact (or low resistance contact that can be regarded as ohmic contact) between silicon and the metal wiring. ) Is not sufficiently obtained, and an electrical connection failure occurs in the connection portion. As a result, it has been found that a desired detection sensitivity cannot be obtained.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a capacitance type mechanical quantity detection sensor that eliminates defective wiring connections in the internal wiring of a sensor and suppresses defective products.

The mechanical quantity detection sensor according to the present invention has a structure in which a semiconductor substrate is interposed between an upper support substrate and a lower support substrate, and the semiconductor substrate supports an upper support substrate at its upper end and a lower support at its lower end. A frame portion that is bonded to the substrate and has an opening, a weight body disposed in the opening, and a connection portion that flexibly connects the weight body and the frame portion. The upper support substrate has an upper electrode on its lower surface, and the lower support substrate has a lower electrode on its upper surface, the upper electrode, the sensor portion, and the lower electrode A mechanical quantity detection sensor in which capacitive elements are formed vertically with the sensor unit, wherein the semiconductor substrate is disposed in the frame, and is formed of silicon containing impurities by connecting the upper support substrate and the lower support substrate. becomes Comprising a pillar, at least one of the upper or lower ends of the struts, and connecting the said upper support substrate or the lower support substrate struts, Al, Au, Pt, from the recognized conductive material any of Cu The upper electrode and the lower electrode include a detection electrode that detects a change in capacitance of a capacitive element, and a drive electrode that vibrates and drives the weight body in the vertical direction. Each of the upper electrode and the lower electrode has a wiring portion that is integrated with and extended from the electrode, and the support column is connected to the wiring portion by the connecting portion, and the upper support substrate and / or the lower electrode The support column is connected to the support substrate, and the support column has a cutout portion with respect to one of the upper end surface and the lower end surface of the support substrate and the side surface of the support column. There is disposed in the notch so as to protrude from the upper end or lower end of the strut prior to coupling with the support column and the lower support substrate, characterized in that collapse during coupling and is connected to the wiring part .

The mechanical quantity detection sensor according to the present invention has a structure in which a semiconductor substrate is interposed between an upper support substrate and a lower support substrate, and the semiconductor substrate supports an upper support substrate at its upper end and a lower support at its lower end. A frame portion that is bonded to the substrate and has an opening, a weight body disposed in the opening, and a connection portion that flexibly connects the weight body and the frame portion. The upper support substrate has an upper electrode on its lower surface, and the lower support substrate has a lower electrode on its upper surface, the upper electrode, the sensor portion, and the lower electrode A mechanical quantity detection sensor in which capacitive elements are formed vertically with the sensor unit, wherein the semiconductor substrate is disposed in the frame, and is formed of silicon containing impurities by connecting the upper support substrate and the lower support substrate. Become A column is provided, and the upper support substrate or the lower support substrate and the support column are connected to at least one of the upper end or the lower end of the support column, and a conductive material made of any one of Al, Au, Pt, and Cu is used. The upper electrode and the lower electrode include a detection electrode that detects a change in capacitance of a capacitive element, and a drive electrode that vibrates and drives the weight body in the vertical direction. Each of the upper electrode and the lower electrode has a wiring portion that is integrated with and extended from the electrode, and the support column is connected to the wiring portion by the connecting portion, and the upper support substrate and / or the lower electrode It is connected to a support substrate, and the support column has a notch with respect to either one of its upper end or lower end and the side surface of the support column, and the connection unit is disposed in the notch. Some of the serial connection unit is characterized in that protrudes from the side surface of the strut.

According to the present invention, in the capacitance type mechanical quantity detection sensor, it is possible to eliminate defective wiring connections and suppress product defects.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Structure of mechanical quantity detection sensor>
FIG. 1 is an exploded perspective view showing a state in which the mechanical quantity detection sensor 100 is disassembled. The mechanical quantity sensor 100 is configured by sandwiching a semiconductor substrate W between an upper support substrate 140 and a lower support substrate 150 positioned above and below the semiconductor substrate W. The semiconductor substrate W is configured by sequentially stacking a first structure 110, a joint 120, and a second structure 130. The semiconductor substrate W is manufactured by a manufacturing process as will be described later. The frame has an opening that penetrates the inside of the semiconductor substrate W (the fixed portion 111 in the first structure 110 and the base 131 in the second structure 130. And a weight body (a displacement portion 112 in the first structure 110 and a weight portion 132 in the second structure 120) supported in a displaceable manner by the flexible connection portion 113 in the frame. Are formed integrally and form a sensor unit for detecting a mechanical quantity. Furthermore, it has a support | pillar (it is comprised by laminating | stacking the support | pillar upper layer part 114, the conjugate | zygote 120, and the support | pillar lower layer part 134) so that a vertical support substrate (140, 150) may be connected in a flame | frame.
FIG. 2 is an exploded perspective view showing a state in which a part of the mechanical quantity detection sensor 100 (the first structure 110 and the second structure 130) is further disassembled. 3, 4, and 5 are top views of the first structure 110, the joint 120, and the second structure 130, respectively. 6, 7, and 8 are a bottom view of the upper support substrate 140, a top view of the lower support substrate 150, and a bottom view of the lower support substrate 150, respectively. 9 and 10 are cross-sectional views showing a state in which the mechanical quantity detection sensor 100 is cut along BB and CC in FIG. 1, and FIG. 11 shows six sets of capacities in the mechanical quantity detection sensor 100. It is sectional drawing which shows an element, FIG. 12 is an enlarged view of the connection location of a support | pillar and a wiring layer. FIG. 13 is a cross-sectional view along the line BB showing the manufacturing method of the mechanical quantity detection sensor 100. FIG. 14 is a schematic diagram showing the relationship between the digging amount (D) of the notch before the anodic bonding and the protruding amount (X) with respect to the column end surface of the connecting portion.

The outer periphery of the first structure 110, the joint 120, the second structure 130, the upper support substrate 140, and the lower support substrate 150 is, for example, a substantially square shape with sides of 3 to 5 mm. For example, they are 20 μm, 2 μm, 600 μm, 500 μm, and 500 μm, respectively.
The first structure 110, the joint 120, and the second structure 130 can be made of silicon, silicon oxide, and silicon, respectively. The mechanical quantity detection sensor 100 has a three-layer structure of silicon / silicon oxide / silicon. It can be manufactured using an SOI (Silicon On Insulator) substrate. It is preferable that the silicon included in the first structure body 110 and the second structure body 130 has conductivity that contains impurities such as boron as a whole. As will be described later, the wiring of the mechanical quantity detection sensor 100 can be simplified by configuring the first structure body 110 and the second structure body 130 with silicon containing impurities. In this embodiment mode, silicon containing impurities is used for the first structure body 110 and the second structure body 130.
Each of the upper support substrate 140 and the lower support substrate 150 is made of a glass material, and for example, a glass material (pyrex (registered trademark) glass) containing movable ions such as sodium is used.

  The first structure 110 includes a fixed portion 111 (111a to 111c), a displacement portion 112 (112a to 112e), a connection portion 113 (113a to 113d), and a support upper layer portion 114 (114a to 114j). The first structure 110 can be formed by etching the semiconductor material film to form the openings 114a to 114d and the support upper layer portions 114a to 114j.

  The fixed part 111 can be divided into a frame part 111a and projecting parts 111b and 111c. The frame part 111a is a frame-shaped substrate whose outer periphery and inner periphery are both substantially square. The protruding portion 111b is disposed at a corner portion on the inner periphery of the frame portion 111a, and protrudes toward the displacement portion 112b (when the X direction of the XY plane is 0 °, the 0 ° direction). It is. The protruding portion 111c is disposed at a corner portion on the inner periphery of the frame portion 111a, and protrudes toward the displacement portion 112d (when the X direction of the XY plane is 0 °, in a 180 ° direction), a substantially square substrate. It is. The frame portion 111a and the protruding portions 111b and 111c are integrally configured.

  The displacement part 112 is comprised from the displacement parts 112a-112e. The displacement portion 112 a is a substrate having a substantially square outer periphery, and is disposed in the vicinity of the center of the opening of the fixed portion 111. The displacement portions 112b to 112e are substrates having a substantially square outer periphery, and are connected and arranged so as to surround the displacement portion 112a from four directions (X-axis positive direction, X-axis negative direction, Y-axis positive direction, and Y-axis negative direction). The entire displacement portion 112 has, for example, a substantially clover-like shape in the vertical view. The displacement parts 112 a to 112 e are joined to weight parts 132 a to 132 e described later by the joining part 120, and are displaced integrally with the fixing part 111.

  The upper surface of the displacement portion 112a functions as a drive electrode E1 (described later). The driving electrode E1 on the upper surface of the displacement portion 112a is capacitively coupled to a driving electrode 144a, which will be described later, installed on the lower surface of the upper support substrate 140, and the displacement portion 112 is moved in the Z-axis direction by a voltage applied therebetween. Vibrate. Details of this drive will be described later.

  The upper surfaces of the displacement portions 112b to 112e function as detection electrodes E1 (described later) that detect displacement of the displacement portion 112 in the X-axis and Y-axis directions. The detection electrodes on the upper surfaces of the displacement portions 112b to 112e are capacitively coupled to detection electrodes 144b to 144e (described later) installed on the lower surface of the upper support substrate 140, respectively (the alphabets b to e of the displacement portion 112, and The alphabets b to e of the detection electrode 144 correspond to each other in order). Details of this detection will be described later.

  The connection portions 113a to 113d are substantially rectangular substrates, and the fixed portion 111 and the displacement portion 112a are arranged in four directions (45 °, 135 °, 225 °, 315 ° when the X direction of the XY plane is 0 °). Direction). The connecting portions 113a to 113d are joined to a projecting portion 131c (described later) of the pedestal 131 by a joining portion 120 in a region near the frame portion 111a. In the other regions of the connecting portions 113a to 113d, that is, the region closer to the displacement portion 112a, the protrusion 131c is not formed in the corresponding region, and the thickness is small, so that the region has flexibility. The reason why the regions near the frame portion 111a of the connection portions 113a to 113d are joined to the protruding portion 131c is to prevent the connection portions 113a to 113d from being damaged by a large deflection. The connecting portions 113a to 113d function as beams that can be bent. The displacement part 112 can be displaced with respect to the fixed part 111 by bending the connection parts 113a to 113d.

  The support | pillar upper layer part 114 is comprised from support | pillar upper layer part 114a-114j. The support upper layer portions 114 a to 114 j are substantially square substrates, and are disposed along the inner periphery of the fixed portion 111 and around the displacement portion 112.

  The column upper layer portions 114h and 114a have end surfaces that face the end surface of the displacement portion 112e, the column upper layer portions 114b and 114c have end surfaces that face the end surface of the displacement portion 112b, and the column upper layer portions 114d and 114e The column upper layer portions 114f and 114g have end surfaces opposite to the end surfaces of the displacement portion 112c. As shown in FIG. 1, each of the support upper layer portions 114 a to 114 h has an end surface facing one of the eight end surfaces of the displacement portion 112 and is arranged clockwise in alphabetical order. The support upper layer portion 114i and the support upper layer portion 114j are disposed in directions of 90 ° and 270 °, respectively, when the X direction of the XY plane is set to 0 °.

The column upper layer portions 114a to 114h are respectively bonded to column lower layer portions 134a to 134h described later by the bonding portion 120 (the alphabets a to h of the column upper layer portion 114 and the alphabets a to h of the column lower layer portion 134 are Each corresponds in turn).
The support upper layer portion 114 and the support lower layer portion 134 connect the upper support substrate 140 and the lower support substrate 150 and are used for wiring. Details of this will be described later.

  The second structure 130 has a substantially square outer shape, and includes a pedestal 131 (131a to 131d), a weight part 132 (132a to 132e), and a support lower layer part 134 (134a to 134j). The second structural body 130 can be created by etching the semiconductor substrate W to form the opening 133, the support lower layer portions 134a to 134j, and the pocket 135 (described later). The pedestal 131 and the support lower layer portions 134a to 134j are substantially equal in height to each other, and the weight portion 132 is lower in height than the pedestal 131 and the support lower layer portions 134a to 134j. This is because a gap (gap) is secured between the weight part 132 and the lower support substrate 150 and the weight part 132 can be displaced. The pedestal 131, the support lower layer portions 134a to 134j, and the weight portion 132 are arranged separately from each other.

The pedestal 131 can be divided into a frame part 131a and projecting parts 131b to 131d.
The frame portion 131 a is a frame-shaped substrate having both an outer periphery and an inner periphery that are substantially square, and has a shape corresponding to the frame portion 111 a of the fixed portion 111.
The protruding portion 131b is disposed at a corner portion on the inner periphery of the frame portion 131a, and protrudes toward the weight portion 132b (when the X direction of the XY plane is 0 °, the 0 ° direction). And has a shape corresponding to the protruding portion 111b of the fixed portion 111.

  The protrusions 131c are four substantially rectangular substrates. When the X direction of the XY plane is 0 °, the protrusions 131c extend from the frame portion 131a to the weight portion 132a in 45 °, 135 °, 225 °, and 315 ° directions. Each projecting, one end connected to the frame 131a of the base 131, and the other end spaced apart from the weight 132a. The protrusion 131c is formed in a substantially half region on the frame 131a side among the regions corresponding to the connection portions 113a to 113d, and is formed in another region, that is, a substantially half region on the weight part 132 side. It has not been.

The protruding portion 131d is disposed at a corner portion on the inner periphery of the frame portion 131a, and protrudes toward the weight portion 132d (when the X direction of the XY plane is 0 °, the 180 ° direction). Inside, a pocket 135 (opening) penetrating the front and back surfaces of the substrate is formed, and is joined to the protruding portion 111c of the fixed portion 111.
The pocket 135 is, for example, a rectangular parallelepiped space in which a getter material for maintaining a high vacuum is placed. One open end of the pocket 135 is covered with a joint 120. The other open end of the pocket 135 is largely covered by the lower support substrate 150, but a portion near the weight portion 132 is not covered, and the other open end and the weight portion 132 are formed. The opening 133 is partially communicated (not shown). The getter material adsorbs residual gas for the purpose of increasing the degree of vacuum in the vacuum-sealed mechanical quantity detection sensor 100, and is made of, for example, an alloy mainly composed of Ti (titanium) or Zr (zirconium). be able to. As long as the residual gas (for example, oxygen generated during anodic bonding) can be adsorbed, the material is not limited to the getter material.
The frame portion 111a and the protruding portions 131b to 131d are integrally configured.
The pedestal 131 is connected to the fixed portion 111 and predetermined regions of the connection portions 113a to 113d by the joint portion 120.

The weight part 132 has a mass and functions as a weight (acting body) that receives a force caused by acceleration or a Coriolis force caused by angular velocity.
The weight part 132 is divided into substantially rectangular parallelepiped weight parts 132a to 132e. The weight portions 132b to 132e are connected to the weight portion 132a disposed at the center from four directions, and can be displaced (moved or rotated) integrally as a whole. That is, the weight part 132a functions as a connection part for connecting the weight parts 132b to 132e. The entire weight part 132 has, for example, a substantially clover-like shape in a vertical view.

  Each of the weight portions 132a to 132e has a substantially square cross-sectional shape corresponding to the displacement portions 112a to 112e, and is joined to the displacement portions 112a to 112e by the joining portion 120. The displacement portion 112 is displaced according to the force applied to the weight portion 132, and as a result, the mechanical quantity can be measured.

  The reason why the weight part 132 is configured by the weight parts 132a to 132e is to achieve both miniaturization and high sensitivity of the mechanical quantity detection sensor 100. If the mechanical quantity detection sensor 100 is reduced in size (smaller capacity), the capacity of the weight part 132 is also reduced, and the mass thereof is reduced, so that the sensitivity to the mechanical quantity is also reduced. The weight parts 132b to 132e are distributed and arranged so as not to hinder the bending of the connection parts 113a to 113d, thereby securing the mass of the weight part 132. As a result, it is possible to achieve both miniaturization and high sensitivity of the mechanical quantity detection sensor 100.

  The lower surface of the weight portion 132a functions as a drive electrode E1 (described later). The driving electrode E1 on the lower surface of the weight portion 132a is capacitively coupled to a driving electrode 154a, which will be described later, installed on the upper surface of the lower support substrate 150, and the displacement portion 112 is moved in the Z-axis direction by the voltage applied therebetween. Vibrate. Details of this drive will be described later.

  The lower surfaces of the weight portions 132b to 132e function as detection electrodes E1 (described later) that detect displacement of the displacement portion 112 in the X-axis and Y-axis directions. The detection electrodes E1 on the lower surfaces of the weight portions 132b to 132e are capacitively coupled to detection electrodes 154b to 154e (described later) installed on the upper surface of the lower support substrate 150, respectively (the alphabets b to e of the weight portions 132). The alphabets b to e of the detection electrode 154 correspond to each other in order). Details of this detection will be described later.

  The support lower layer portions 134a to 134j have substantially square cross-sectional shapes corresponding to the support upper layer portions 114a to 114j, respectively, and are joined to the support upper layer portions 114a to 114j by the joint portion 120. The struts joining the strut upper layer portions 114a to 114h and the strut lower layer portions 134a to 134h are hereinafter referred to as “struts a to h”, respectively. The columns a to h are used as wirings for guiding the electrodes 144b to 144e and 154b to 154e to the outside of the sensor (for connecting to wiring terminals T described later). Columns (hereinafter referred to as “columns i and j”, respectively) joining the column upper layer portions 114i and 114j and the column lower layer portions 134i and 134j are connected to electrodes for vibrating the displacement unit 112 in the Z-axis direction. Used for wiring purposes. A connecting portion 170 made of a conductive material is formed on the lower surface of the support lower layer portions 134j, 134c, 134d, 134g, and 134h connected to the wiring layers L2, L8, L9, L10, and L11. And are connected to a wiring terminal T to be described later.

The joint 120 connects the first and second structures 110 and 130. The joining portion 120 includes a joining portion 121 that connects the predetermined region of the connecting portion 113 and the fixing portion 111 and the base 131, and a joining portion 122 (122a to 122e) that connects the displacement portions 112a to 112e and the weight portions 132a to 133e. ) And the joints 123 (123a to 123j) connecting the support upper layer portions 114a to 114j and the support lower layer portions 134a to 134j. The joint 120 does not connect the first and second structures 110 and 130 at other portions. This is because the connecting portions 113a to 113d can be bent and the weight portion 132 can be displaced.
The junctions 121, 122, and 123 can be configured by etching a silicon oxide film.

Conductive portions 160 to 162 are formed to connect the first structure 110 and the second structure 130 at necessary portions. The conducting part 160 conducts the fixed part 111 and the pedestal 131, and penetrates the protruding part 111 b and the joining part 121 of the fixed part 111. The conduction part 161 conducts the displacement part 112 and the weight part 132, and penetrates the displacement part 112 a and the joint part 122. The conduction part 162 conducts the support upper layer parts 114a, 114b, 114e, 114f, 114i and the support lower layer parts 134a, 134b, 134e, 134f, 134i, respectively. The support upper layer parts 114a, 114b, 114e, 114f, 114i and the joint 123 are respectively penetrated.
The conduction parts 160 to 162 are formed, for example, by forming a metal layer such as Al on the edge, wall surface, and bottom of the through hole. Although the shape of the through hole is not particularly limited, it is preferable that the through holes of the conductive portions 160 to 162 have a forward tapered cone shape because the metal layer can be effectively formed by sputtering such as Al.

  The upper support substrate 140 is made of, for example, a glass material, has a substantially rectangular parallelepiped outer shape, and includes a frame portion 141 and a bottom plate portion 142. The frame portion 141 and the bottom plate portion 142 can be formed by forming a concave portion 143 having a substantially rectangular parallelepiped shape (for example, a vertical and horizontal square of 1.5 to 2.5 mm and a depth of 5 μm) so that the weight body can be displaced on the substrate. . The concave portion 143 can be appropriately set according to a value corresponding to the maximum displacement amount of the displacement portion 112 and a desired detection sensitivity.

  The frame part 141 is a frame-shaped substrate shape whose outer periphery and inner periphery are both substantially square. The outer periphery of the frame part 141 coincides with the outer periphery of the fixed part 111, and the inner periphery of the frame part 141 is smaller than the inner periphery of the fixed part 111. The bottom plate portion 142 has a substantially square substrate shape whose outer periphery is substantially the same as the frame portion 141. The reason why the concave portion 143 is formed in the upper support substrate 140 is to secure a space for the displacement portion 112 to be displaced. The first structure 110 other than the displacement part 112, that is, the fixed part 111 and the support upper layer parts 114a to 114j are joined to the upper support substrate 140 by, for example, anodic bonding.

  A driving electrode 144a and detection electrodes 144b to 144e are disposed on the bottom plate portion 142 (the lower surface of the upper support substrate 140) so as to face the displacement portion 112. The drive electrode 144a and the detection electrodes 144b to 144e can be made of a conductive material. The driving electrode 144a has, for example, a substantially cross shape, and is formed at the center of the recess 143 so as to face the displacement portion 112a. The detection electrodes 144b to 144e are substantially square, respectively, and surround the drive electrode 144a from four directions (X-axis positive direction, X-axis negative direction, Y-axis positive direction, and Y-axis negative direction). It is arranged to face 112e. The drive electrode 144a and the detection electrodes 144b to 144e are separated from each other.

  A wiring layer L1 electrically connected to the upper surface of the support upper layer portion 114i is connected to the driving electrode 144a. The detection electrode 144b is electrically connected to the upper surface of the support upper layer portion 114b. The detection electrode 144c is electrically connected to the upper surface of the support upper layer portion 114e. The detection electrode 144b is electrically connected to the upper surface of the support upper layer portion 114e. A wiring layer L6 electrically connected to the upper surface of the support pillar upper layer portion 114f is connected to the electrode 144d, and a wiring layer L7 electrically connected to the upper surface of the support pillar upper layer portion 114a is connected to the detection electrode 144e. Yes.

  For example, Al containing Nd can be used as a constituent material of the drive electrode 144a, the detection electrodes 144b to 144e, and the wiring layers L1 and L4 to L7. By using Al containing Nd for the drive electrode 144a and the detection electrodes 144b to 144e (Nd content: 1.5 to 10 at%), a heat treatment process described later (anodic bonding of the upper support substrate 140 or the lower support substrate 150) In addition, the generation of hillocks in the drive electrode 144a and the detection electrodes 144b to 144e can be suppressed by activation of the getter material. The hillock here refers to, for example, a hemispherical protrusion. Accordingly, the distance between the driving electrode 144a and the driving electrode E1 (capacitively coupled to the driving electrode 144a) formed on the upper surface of the displacement portion 112a, the detection electrodes 144b to 144e, and the displacement portion The dimensional accuracy of the distance between the detection electrodes E1 (capacitively coupled to the detection electrodes 144b to 144e, respectively) formed on the upper surfaces of the 112b to 112e can be increased.

The lower support substrate 150 is made of, for example, a glass material and has a substantially square substrate shape.
The lower support substrate 130 other than the weight portion 132, that is, the pedestal 131 and the support lower layer portions 134a to 134j are joined to the lower support substrate 150 by, for example, anodic bonding. The weight part 132 is not joined to the lower support substrate 150 because the height is lower than the base 131 and the support lower layer parts 134a to 134j. This is because a gap (gap) is secured between the weight part 132 and the lower support substrate 150 and the weight part 132 can be displaced.

  On the upper surface of the lower support substrate 150, a driving electrode 154a and detection electrodes 154b to 154e are disposed so as to face the weight portion 132. The drive electrode 154a and the detection electrodes 154b to 154e can be made of a conductive material. The driving electrode 154a has, for example, a cross shape and is formed near the center of the upper surface of the lower support substrate 150 so as to face the weight portion 132a. Each of the detection electrodes 154b to 154e is substantially square, and surrounds the drive electrode 154a from four directions (X-axis positive direction, X-axis negative direction, Y-axis positive direction, and Y-axis negative direction). It is arranged to face 132e. The drive electrode 154a and the detection electrodes 154b to 154e are separated from each other.

  A wiring layer L2 that is electrically connected to the lower surface of the support lower layer portion 134j is connected to the driving electrode 154a. The detection electrode 154b has a wiring layer L8 electrically connected to the lower surface of the support lower layer portion 134c. The detection electrode 154c has a wiring layer L9 electrically connected to the lower surface of the support lower layer portion 134d. The electrode 154d is connected to the wiring layer L10 electrically connected to the lower surface of the support lower layer part 134g, and the detection electrode 154e is connected to the wiring layer L11 electrically connected to the lower surface of the support lower layer part 134h. Yes. A connecting portion 170 made of a conductive material is formed on the lower surface of the support lower layer portions 134j, 134c, 134d, 134g, and 134h connected to the wiring layers L2, L8, L9, L10, and L11. Are connected, and each electrode and the column are electrically connected. In addition, the connection part 170 which consists of an electroconductive material may be formed in the upper surface of the support | pillar upper layer part 114i, 114b, 114e, 114f, 114a connected with wiring layer L1, L4, L5, L6, L7.

  As a constituent material of the drive electrode 154a, the detection electrodes 154b to 154e, and the wiring layers L2 and L8 to L11, for example, Al containing Nd can be used. By using Al containing Nd for the drive electrode 154a and the detection electrodes 154b to 154e (Nd content: 1.5 to 10 at%), a heat treatment process described later (when forming an ohmic contact between the semiconductor substrate and the connecting portion 170) , Anodic bonding of the lower support substrate 150 and activation of the getter material) can suppress the generation of hillocks in the drive electrode 154a and the detection electrodes 154b to 154e. Accordingly, the distance between the driving electrode 154a and the driving electrode E1 (capacitively coupled to the driving electrode 154a) formed on the lower surface of the weight part 132a, the detection electrodes 154b to 154e, and the weight part The dimensional accuracy of the distance between the detection electrodes E1 (capacitively coupled to the detection electrodes 154b to 154e, respectively) formed on the lower surfaces of the 132b to 132e can be increased.

  The lower support substrate 150 is provided with wiring terminals T (T1 to T11) penetrating the lower support substrate 150, and driving electrodes 144a and 154a and detection electrodes 144b to 144e from the outside of the mechanical quantity detection sensor 100. , 154b to 154e.

  The upper end of the wiring terminal T1 is connected to the lower surface of the protrusion 131b of the base 131. The wiring terminals T2 to T9 are connected to the lower surfaces of the support lower layers 134a to 134h, respectively (the numbers T2 to T9 of the wiring terminals T2 to T9 and the alphabets 134a to 134h of the support lower layers 134a to 134h). Order corresponds to each). The wiring terminals T10 and T11 are respectively connected to the lower surfaces of the support lower layer portions 134i and 134j.

As shown in FIGS. 9 and 10, the wiring terminal T is formed by forming a metal film such as Al on the edge, wall surface, and bottom of a forward tapered cone-shaped through-hole, for example. It has the same structure as 162. The wiring terminal T can be used as a connection terminal for connecting to an external circuit (not shown) by, for example, wire bonding.
In FIG. 1 to FIG. 10, the lower support substrate 150 is illustrated below in consideration of the visibility of the first structure 110, the joint 120, and the second structure 130. . When the wiring terminal T and the external circuit (not shown) are connected by, for example, wire bonding, the lower support substrate 150 of the mechanical quantity detection sensor 100 can be arranged, for example, so as to be easily connected. it can.

<Wiring of mechanical quantity detection sensor>
The wiring and electrodes of the mechanical quantity detection sensor 100 will be described.
FIG. 11 is a cross-sectional view showing six sets of capacitive elements in the mechanical quantity detection sensor 100 shown in FIG. In FIG. 11, portions that function as electrodes are indicated by hatching. In FIG. 11, six sets of capacitive elements are illustrated, but as described above, ten sets of capacitive elements are formed in the mechanical quantity detection sensor 100.
One electrode of the 10 sets of capacitive elements includes a drive electrode 144a and detection electrodes 144b to 144e formed on the upper support substrate 140, and a drive electrode 154a and detection electrodes 154b to 154e formed on the lower support substrate 150. It is.
The other electrodes are the driving electrode E1 on the upper surface of the displacement portion 112a, the detection electrode E1 formed on the upper surface of the displacement portions 112b to 112e, the driving electrode E1 on the lower surface of the weight portion 132a, and the weight portions 132b to 132b. It is the electrode E1 for a detection formed in the lower surface of 132e, respectively. Since the first structure body 110 and the second structure body 130 are formed using a conductive material (silicon containing impurities), the support column can function as a wiring.

  Since the capacitance of the capacitor is inversely proportional to the distance between the electrodes, it is assumed that the driving electrode E1 and the detection electrode E1 are on the upper surface of the displacement portion 112 and the lower surface of the weight portion 132. That is, the drive electrode E1 and the detection electrode E1 are not formed separately on the upper surface of the displacement portion 112 or the surface layer of the lower surface of the weight portion 132. It is assumed that the upper surface of the displacement portion 112 and the lower surface of the weight portion 132 function as the drive electrode E1 and the detection electrode E1.

The driving electrode 144a and the detection electrodes 144b to 144e formed on the upper support substrate 140 are in order of the pillar upper layer portions 114i, 114b, 114e, 114f, and 114a via the wiring layers L1 and L4 to L7 and the connecting portion 170, respectively. And are electrically connected. Further, the support upper layer portions 114i, 114b, 114e, 114f, and 114a and the support lower layer portions 134i, 134b, 134e, 134f, and 134a are electrically connected to each other by the conductive portion 162.
The drive electrodes 154a and the detection electrodes 154b to 154e formed on the lower support substrate 150 are in order of the support lower layers 134j, 134c, 134d, 134g, and 134h via the wiring layers L2, L8 to L11 and the connecting portion 170, respectively. And are electrically connected.

  Therefore, the wirings for the drive electrodes 144a and 154a and the detection electrodes 144b to 144e and 154b to 154e may be connected to the lower surfaces of the support lower layers 134a to 134j. The wiring terminals T2 to T9 are respectively disposed on the lower surfaces of the support lower layers 134a to 134h, and the wiring terminals T10 and T11 are disposed on the lower surfaces of the support lower layers 134i and 134j, respectively.

  As described above, the wiring terminals T2 to T11 are electrically connected to the detection electrodes 144e, 144b, 154b, 154c, 144c, 144d, 154d, 154e, and the driving electrodes 144a, 154a, respectively.

  The drive electrode E1 and the detection electrode E1 are respectively formed from the upper surface of the displacement portion 112 and the lower surface of the weight portion 132. The displacement part 112 and the weight part 132 are electrically connected by the conduction part 161, and both are made of a conductive material. The pedestal 131 and the fixed part 111 are electrically connected by a conductive part 160, both of which are made of a conductive material. The displacement part 112, the connection part 113, and the fixing part 111 are integrally formed of a conductive material. Therefore, the wiring for the drive electrode E1 and the detection electrode E1 may be connected to the lower surface of the pedestal 131. The wiring terminal T1 is disposed on the lower surface of the protrusion 131b of the pedestal 131, and the wiring terminal T1 is electrically connected to the driving electrode E1 and the detection electrode E1.

  As described above, since the first structure body 110 and the second structure body 130 are made of a conductive material (silicon containing impurities), the support upper layer portions 114a to 114j and the support lower layer portions 134a to 134a. The pillars a to j joined with 134j can be provided with a function as wiring, and wiring for the capacitor can be simplified.

If a functional part such as an element is formed in the manufacturing process of a MEMS product typified by a mechanical quantity detection sensor, the cleaning method is limited, and it may be difficult to obtain a clean interface. For example, if the interface is washed with an acid or alkali while the element is formed, the formed fragile element structure may be damaged. On the other hand, if a normal interface cannot be obtained, a defect may occur in the connection between the semiconductor and the metal.
Therefore, by using the connecting portion 170 that is preliminarily connected to the semiconductor (ohmic contact or low resistance contact that can be regarded as an ohmic contact), the connection with the wiring layer L is easier than the electrical connection between the semiconductor and the metal. Therefore, good electrical characteristics can be obtained.
Further, in order to improve the connection failure between the strut (particularly the strut lower layer portion 134) and the wiring layer L, it is conceivable to increase the applied voltage and temperature during anodic bonding. However, a predetermined time is required until the connection is stabilized after the voltage application of the anodic bonding, and the following failure may be caused before the stabilization. Specifically, if the connection between the support column and the wiring layer is not achieved, the potential of the electrode portion (drive electrode, detection electrode) that should be the same potential as the support column cannot be determined, and as a result, the weight body There is a possibility that a defect such as sticking after sticking to the upper or lower support substrate due to electrostatic attraction is caused. Therefore, strengthening the joining conditions is not a fundamental solution. In the present invention, a silicon-metal connection is formed before bonding, and at the time of bonding, stable connection between the pillar and the wiring layer can be ensured by contact between the metals at the connecting portion 170, and an anodic bonding process Stabilization, and in turn, yield improvement of the product.

FIG. 12 is an enlarged view of a connecting portion between the support column and the wiring layer L. FIG. The connecting portion 170 can be formed on the entire upper surface of the support upper layer portion 114 and / or the entire lower surface of the support lower layer portion 134 or a partial region thereof. Further, as shown in FIG. 12 (B), the connecting portion 170 is formed in the notch portion 180 formed by etching, for example, 0.1 μm to 2 μm, more preferably 0.3 to 1 μm from the end surface of the column by etching the column. A film may be formed.
The sealing at the connection location can be further stabilized by the cutout portion 180, and the connection between the connection portion 170 and the wiring layer L is further facilitated. More preferably, the connecting portion 170 is formed so as to partially or entirely cover the through-hole portion of the wiring terminal T. The connecting portion 170 is formed so as to protrude from the end face of the column by a height of 5 to 50% of the digging amount (D) of the notch portion 180, and is preferably used for anodic bonding (the digging amount of the notch portion ( D) and the protrusion amount (X) of the connecting portion (see FIG. 14). If the protrusion amount (X) is 5% or less, the connection by the connecting portion may be insufficient. Further, when the protrusion amount (X) is 50% or more, there is a possibility that the parallelism between the joint and the sensor gap may be affected, and further, a joint failure may be caused.

<Operation of mechanical quantity detection sensor>
As described above, in the mechanical quantity detection sensor 100, the weight body in which the displacement portion 112 and the weight portion 132 are integrally formed is supported by the flexible connection portion 113 extending from the fixed portion, and the upper support substrate 140 is supported. The lower support substrate 150 and the semiconductor substrate W are configured to be displaceable in a space surrounded by the lower support substrate 150 and the semiconductor substrate W.

  When the mechanical quantity detection sensor 100 is used as an acceleration sensor, the displacement of the weight body caused by the action of acceleration may be detected. For example, if acceleration in the X-axis positive direction is applied to the weight body, the weight body is displaced in the X-axis positive direction by an external force corresponding to the acceleration. The amount of displacement at this time depends on the magnitude of the acting acceleration. Therefore, if the displacement of the weight body in the X-axis, Y-axis, and Z-axis directions is detected, the acceleration value of each axial component can be obtained. In the mechanical quantity detection sensor 100, the acceleration value of each axial component can be detected by detecting a change in capacitance of a capacitive element formed by the weight body and the electrode.

  In the case where the mechanical quantity detection sensor 100 is used as an angular velocity sensor, the weight body is vibrated up and down by a driving electrode (generally, an AC voltage is applied to make a single vibration), and the weight body caused by the action of the angular velocity is detected. What is necessary is just to detect a displacement. For example, when an angular velocity ω is applied when the weight body is moving in the Z-axis direction at a speed vz, the Coriolis force F acts on the weight body. Specifically, according to the angular velocity ωx in the X-axis direction and the angular velocity ωy in the Y-axis direction, the Coriolis force Fy (= 2 · m · vz · ωx) in the Y-axis direction and the Coriolis force Fx (= 2 · m · vz · ωy) acts on the weight body (m is the weight of the weight body). When the Coriolis force Fy due to the angular velocity ωx in the X-axis direction is applied, the displacement portion 112 is inclined in the Y direction. As described above, the Coriolis forces Fy and Fx resulting from the angular velocities ωx and ωy cause the displacement portion 112 to be inclined (displaced) in the Y direction and the X direction. Therefore, if the displacement of the weight body in each axial direction is detected, the value of the angular velocity of each axial component can be obtained. In the mechanical quantity detection sensor 100, the value of the angular velocity of each axial component can be detected by detecting the change in the capacitance of the capacitive element formed by the weight body and the electrode.

  Specifically, when a voltage is applied between the driving electrodes 144a and E1, the driving electrodes 144a and E1 are attracted to each other by the Coulomb force, and the weight body (the displacement portion 112 and the weight portion 132) is displaced in the positive direction of the Z axis. . When a voltage is applied between the drive electrodes 154a and E1, the drive electrodes 154a and E1 are attracted to each other by the Coulomb force, and the displacement portion 112 (also the weight portion 132) is displaced in the Z-axis negative direction. That is, by alternately applying a voltage between the drive electrodes 144a and E1 and between the drive electrodes 154a and E1, the displacement portion 112 (also the weight portion 132) vibrates in the Z-axis direction. The voltage can be applied using a positive or negative direct current waveform (a pulse waveform when considering non-application), a half-wave waveform, or the like. The period of vibration of the displacement part 112 is determined by the period at which the voltage is switched. The switching cycle is preferably close to the natural frequency of the displacement portion 112 to some extent. The natural frequency of the weight body is determined by the elastic force of the connecting portion 113, the mass of the weight portion 132, and the like. If the period of vibration applied to the weight body does not correspond to the natural frequency, the energy of vibration applied to the weight body is diverged and energy efficiency is lowered. Note that an AC voltage having a frequency that is ½ of the natural frequency of the weight body may be applied only to either the drive electrodes 144a and E1 or between the drive electrodes 154a and E1.

  At this time, it is more preferable to arrange a getter in the space (pocket 135), because the Q value increases by increasing the degree of vacuum in the space, and the sensitivity of the sensor increases.

  In general, the angular velocity signal is several kHz or more, and the acceleration signal has a frequency two or more digits lower than the angular velocity signal, so that each can be identified by an external signal processing circuit (not shown). That is, acceleration and angular velocity are filtered by a signal processing circuit provided outside, and the signals following the low frequency component (or bias component) and the vibration frequency are respectively filtered and detected by each to detect three axes. It is possible to detect acceleration in the (X, Y, Z) direction and angular velocity in the biaxial (X, Y) direction. The mechanical quantity detection sensor 100 can be used as a sensor that detects only acceleration / angular velocity.

<Manufacture of mechanical quantity detection sensor 100>
Hereinafter, a description will be given with reference to FIGS.
(1) Preparation of semiconductor substrate W (FIG. 13A)
A semiconductor substrate W is prepared by laminating three layers of first, second, and third layers 11, 12, and 13. The first, second, and third layers 11, 12, and 13 are layers for forming the first structure 110, the joint 120, and the second structure 130, respectively, and include impurities here. The layer is made of silicon, silicon oxide, or silicon containing impurities.

  A semiconductor substrate W having a three-layered structure of silicon containing impurities / silicon oxide / silicon containing impurities includes a substrate in which a silicon oxide film is stacked on a silicon substrate containing impurities, and silicon containing impurities. After bonding the substrate, the silicon substrate containing the latter impurities can be polished to a predetermined thickness (so-called SOI substrate). Here, the silicon substrate containing impurities can be manufactured by doping impurities in the manufacture of a silicon single crystal by the Czochralski method, for example. An example of impurities contained in silicon is boron. As silicon containing boron, for example, silicon containing high-concentration boron and having a resistivity of 0.001 to 0.01 Ω · cm can be used.

  Here, the first layer 11 and the third layer 13 are made of the same material (silicon containing impurities), but the first, second, and third layers 11, 12, and 13 All may be made of different or the same material.

(2) Creation of the first structure 110 (FIG. 13B)
By etching the first layer 11, the opening 115 is formed, and the first structure 110 is formed. That is, an etching method that has erosion with respect to the first layer 11 and does not have erosion with respect to the second layer 12 is applied to predetermined regions (openings 115a to 115d) of the first layer 11. On the other hand, etching is performed in the thickness direction until the upper surface of the second layer 12 is exposed. As such an etching method, for example, a known etching method such as an RIE (Reactive Ion Etching) method can be used. A resist layer having a pattern corresponding to the first structure 110 is formed on the upper surface of the first layer 11, and the exposed portion not covered with the resist layer is eroded vertically downward. In this etching process, since the second layer 12 is not eroded, only predetermined regions (openings 115a to 115d) of the first layer 11 are removed.

(3) Creation of the joint 120 (FIG. 13B)
The joint 120 is formed by etching the second layer 12. That is, the second layer 12 is erodible with respect to the second layer 12 by an etching method that is not erodible with respect to the first layer 11 and the third layer 13. Etching is performed in the thickness direction and the layer direction from the exposed portion. In the etching process for the second layer 12, it is necessary to perform an etching method that satisfies the following two conditions. The first condition is to have directionality in the layer direction as well as the thickness direction, and the second condition is erosive to the silicon oxide layer but erodible to the silicon layer. Is not to. As such an etching method, wet etching using buffered hydrofluoric acid (for example, a mixed aqueous solution of HF = 5.5 wt% and NH ₄ F = 20 wt%) can be given. Further, dry etching by the RIE method using a mixed gas of CF ₄ gas and O ₂ gas is also applicable.

(4) Formation of conduction parts 160 to 162 (FIG. 13C)
The conductive portions 160 to 162 are formed as follows 1) to 2).
1) Formation of conical through-holes A predetermined portion of the first structure 110 and the second layer 12 is wet-etched to form a weight-like through-hole that penetrates to the second layer 12. As the etchant, for example, 20% TMAH (tetramethylammonium hydroxide) can be used in the etching of the first structure 110, and in the etching of the second layer 12, for example, buffered hydrofluoric acid (for example, HF = 5.5 wt%, NH ₄ F = 20 wt% mixed aqueous solution) can be used.

2) Formation of metal layer On the upper surface of the first structure 110 and the conical through hole, for example, Al is deposited by an evaporation method, a sputtering method, or the like to form the conductive portions 160 to 162. Unnecessary metal layers deposited on the upper surface of the first structure 110 (metal layers outside the upper edges (not shown) of the conductive portions 160 to 162) are removed by etching.

(5) Bonding of the upper support substrate 140 (FIG. 13D)
The upper support substrate 140 is joined as described in 1) to 2) below.
1) Creation of upper support substrate 140 For example, a glass substrate containing movable ions is etched to form a recess 143, and a drive electrode 144a, detection electrodes 144b to 144e, and wiring layers L1 and L4 to L7 are formed, for example, Nd It is formed at a predetermined position by a pattern made of Al containing.

2) Bonding of the semiconductor substrate W and the upper support substrate 140 The semiconductor substrate W and the upper support substrate 140 are bonded by, for example, anodic bonding.
The upper support substrate 140 is anodically bonded before the second structure 130 is formed. Since the upper support substrate 140 is anodically bonded before forming the weight portion 132, the connection portions 113a to 113d do not have a thin region and do not have flexibility. Even if it occurs, the displacement portion 112 is not attracted to the upper support substrate 140. For this reason, it is possible to prevent the upper support substrate 140 and the displacement portion 112 from being joined.

(6) Formation of the second structure 130 (FIG. 13E)
The formation of the second structure 130 is performed as follows 1) to 2).
1) Formation of the gap 10 A resist layer is formed on the upper surface of the third layer 13 except for the formation region of the weight portion 132 and its vicinity, and an exposed portion (formation region of the weight portion 132 is not covered with the resist layer). And its vicinity) erode vertically downward. As a result, the gap 10 for enabling the displacement of the weight portion 132 is formed above the region where the weight portion 132 is formed.

2) Formation of the second structure 130 The third layer 13 on which the predetermined mask is formed is etched to form the opening 133, the support lower layer portions 134a to 134j, and the pocket 135, and the second structure 130 is formed. That is, the thickness of the third layer 13 with respect to a predetermined region (opening 133) is determined by an etching method that has erosion with respect to the third layer 13 and does not have erosion with respect to the second layer 12. Etching in the direction.

As such an etching method, an etching method called DRIE (Deep Reactive Ion Etching) can be used. In DRIE, the etching process that digs while eroding the material layer in the thickness direction and the deposition process that forms a polymer wall on the side of the digged hole are alternately repeated, and erosion can proceed only in the thickness direction. become. An etching material having etching selectivity between silicon oxide and silicon may be used. For example, it is conceivable to use a mixed gas of SF ₆ gas and O ₂ gas in the etching stage, and C ₄ F ₈ gas in the deposition stage.

(7) Formation of connecting portion 170 (FIG. 13 (f))
A connecting portion 170 made of a conductive material is formed on a predetermined support connected to the wiring layer. When the wiring layer is made of a metal material, the conductive material layer 170 is preferably made of a metal material in order to make electrical connection suitable. For example, Al or the like is formed on the lower end of the lower layer of the column by sputtering, and heat treatment (about 400 ° C.) is performed to make contact between silicon and metal. The patterning of the connecting portion 170 can be performed by forming a resist mask in a region other than a predetermined region before film formation and removing the resist mask after metal film formation. By providing an ohmic contact between the support column and the connecting portion before anodic bonding, a more reliable mechanical quantity detection sensor can be manufactured.
The material of the connecting portion 170 is (1) low resistance material and excellent electrical characteristics, (2) relatively low hardness, easily crushed by pressing during anodic bonding, and (3) ohmic contact with semiconductor material (silicon) (Or a low resistance contact that can be regarded as an ohmic contact) is possible. Al, Au, Pt, Cu, etc. may be provided with an adhesion layer between the connecting portion and the support substrate in terms of adhesion and reliability with silicon or glass in the formation of ohmic contact. As the adhesion layer, for example, in the case of Al, a laminated body in the order of Ti and TiN from the column side, in the case of Au and Cu, Cr and in the case of Pt, Ti can be used. These adhesion layers can be formed by sputtering or the like. The adhesion layer is appropriately formed with a thickness of about 10 nm to 100 nm.
Note that the connecting portion 170 may be formed in a predetermined region before the second structure 130 is formed.

(8) Bonding of the lower support substrate 150 (FIG. 13G)
The lower support substrate 150 is joined as follows 1) to 2).
1) Creation of lower support substrate 150 For example, a driving electrode 154a, detection electrodes 154b to 154e, and wiring layers L2 and L8 to L11 are predetermined on a glass substrate containing movable ions by a pattern made of Al containing Nd, for example. Form at the position. In addition, by etching the lower support substrate 150, 11 wide conical through holes 10 for forming the wiring terminals T1 to T11 are formed at predetermined positions.

2) Joining of the semiconductor substrate W and the lower support substrate 150 A getter material (for example, trade name non-evaporable getter St122 manufactured by SAES Getters Japan Co., Ltd.) is put in the pocket 135, and the lower support substrate 150 and the semiconductor substrate W are joined, for example, by anodic bonding. To join.

(9) Formation of wiring terminals T <b> 1 to T <b> 11 A metal layer is formed in the order of, for example, a Cr layer and an Au layer on the upper surface of the lower support substrate 150 and the conical through hole 10 by vapor deposition or sputtering. Unnecessary metal layers (metal layers outside the upper edge of the wiring terminal T) are removed by etching to form wiring terminals T1 to T11.

(10) Dicing the semiconductor substrate W, the upper support substrate 140, and the lower support substrate 150 For example, after activating the getter material in the pocket 135 by heat treatment at 400 ° C., the semiconductor substrate W, the upper support substrate 140, Then, the lower support substrate 150 is cut with a dicing saw or the like and separated into individual mechanical quantity detection sensors 100. The activation of the getter material can also serve as anodic bonding between the semiconductor substrate W and the lower support substrate 150.

Example 1
Al, Al (TiN / Ti as the adhesion layer), Au (including Cr as the adhesion layer), Cu (including Cr as the adhesion layer), and Pt (including Ti as the adhesion layer) are formed on the lower layer of the support by sputtering. After forming a 0.20 μm film (as an adhesion layer, TiN is formed with a thickness of 100 nm and Ti is formed with a thickness of 20 nm, and Cr and Ti are formed with a thickness of 50 nm, respectively), four types of samples subjected to bonding were prepared. In each sample, when the electrical characteristics were examined, there was no connection failure between the support column and the wiring L, and good electrical characteristics were obtained. In particular, good electrical characteristics were obtained for the sample in which Al was deposited on the lower layer of the column as compared with other samples. This is presumably because the surface of Al easily forms a metal oxide film by oxidation, and the metal oxide film is anodic bonded to glass at the time of bonding, so that the connection is further facilitated.

(Example 2)
A notch portion of 0.5 μm is formed as the digging amount (D) of the end surface of the support lower layer portion, and the protruding amount (X) with respect to the end surface of the connecting portion (Al) formed in the notch portion is 0.02 μm, 0.05 μm , 0.25 μm and 0.30 μm were prepared as five types of samples. When the protrusion amount (X) was 0.02 μm, there was a chip in which the connection between the support column and the wiring L could not be achieved. Further, when the protrusion amount (X) was 0.30 μm, a chip with poor anodic bonding was present. On the other hand, when the protrusion amount (X) was 0.05 μm and 0.25 μm, the connection between the support column and the wiring L was appropriately achieved, and good electrical characteristics were obtained.

(Comparative Example 1)
A sample was formed by joining without forming a connecting portion in the lower layer of the column. At this time, failure modes such as poor connection and sticking of the weight body to the glass substrate were observed in the mechanical quantity detection sensor 100 in the wafer that was multifaceted.

<< Other Embodiments >>
Embodiments of the present invention are not limited to the above-described embodiments, and can be expanded and modified. The expanded and modified embodiments are also included in the technical scope of the present invention.

<< Electronic parts using the mechanical quantity detection sensor 100 >>
The mechanical quantity detection sensor 100 according to the present invention is mounted on a circuit board on which an active element such as an IC is mounted, for example, and is connected to a wiring terminal T and an electronic circuit board or IC by a known method and material such as wire bonding connection. It connects with active elements, such as, and functions as one electronic component. For example, the electronic component is mounted on a mobile terminal such as a game machine or a mobile phone and is distributed in the market.

It is a disassembled perspective view showing the state which decomposed | disassembled the mechanical quantity detection sensor 100 which concerns on embodiment of this invention. It is a disassembled perspective view showing the state which decomposed | disassembled the mechanical quantity detection sensor 100 of FIG. 3 is a top view of the first structure 110. FIG. 3 is a top view of a joint portion 120. FIG. 3 is a top view of the second structure 130. FIG. 4 is a bottom view of an upper support substrate 140. FIG. 3 is a top view of a lower support substrate 150. FIG. 6 is a bottom view of a lower support substrate 150. FIG. It is sectional drawing showing the state cut | disconnected along BB of FIG. It is sectional drawing showing the state cut | disconnected along CC of FIG. It is sectional drawing which shows six sets of capacitive elements in the mechanical quantity detection sensor 100 shown in FIG. FIG. 4 is an enlarged view of a connection portion between a support column and a wiring layer L. It is sectional drawing along BB showing the manufacturing method of the physical quantity detection sensor 100 which concerns on embodiment of this invention. It is a schematic diagram which shows the relationship between the digging amount (D) of the notch part before anodic bonding, and the protrusion amount (X) with respect to the support | pillar end surface of a connection part.

Explanation of symbols

100: Mechanical quantity detection sensor 110: First structure 111: Fixed part 111a: Frame part 111b, 111c: Projection part 112 (112a-112e): Displacement part 113 (113a-113d): Connection part 114 (114a-114j) ): Support upper layer portion 115 (115a-115d): openings 120, 121, 122, 123: joint portion 130: second structure 131: pedestal 131a: frame portions 131b to 131d: protrusion 132 (132a-132e): Weight part 133: opening 134 (134a-134j): support lower layer part 135: pocket 140: upper support substrate 141: frame part 142: bottom plate part 143: recess 144a: driving electrode 144b-144e: detection electrode 150: lower support Substrate 154a: Driving electrodes 154b-154e: Detection electrodes 160-162: Conducting portion 170: Connecting portion 180 Notch 10: Gap 11: conical through holes L1, L2, L4-L11: wiring layer T1-T11: wiring terminals E1: the driving electrode, detection electrode

Claims (3)

The semiconductor substrate has a structure in which a semiconductor substrate is sandwiched between an upper support substrate and a lower support substrate. The semiconductor substrate has an upper end bonded to the upper support substrate and a lower end bonded to the lower support substrate, and has an opening. A sensor unit including a frame part, a weight body disposed in the opening, and a connection part that flexibly connects the weight body and the frame part; The support substrate has an upper electrode on its lower surface, the lower support substrate has a lower electrode on its upper surface, and the upper electrode and the sensor unit, and the lower electrode and the sensor unit have capacitive elements vertically. A mechanical quantity detection sensor formed,
The semiconductor substrate includes a support column made of silicon that is disposed in the frame and connects the upper support substrate and the lower support substrate and contains impurities, and the upper support substrate is provided on at least one of an upper end and a lower end of the support column. Alternatively, the lower support substrate and the support column are connected, and a connecting portion made of a conductive material made of any one of Al, Au, Pt, and Cu is provided .
The upper electrode and the lower electrode include a detection electrode that detects a change in electrostatic capacitance of a capacitive element, and a drive electrode that vibrates and drives the weight body in the vertical direction, and the upper electrode or the lower electrode Each has a wiring portion that is integrated and extended with the electrode, and the column is connected to the wiring portion by the connecting portion, and is connected to the upper supporting substrate and / or the lower supporting substrate. And
The strut has a notch portion with respect to either one of its upper end or lower end and the side of the strut,
Prior to the connection between the upper support substrate or the lower support substrate and the support column, the connection unit is disposed in the notch so as to protrude from the upper end or the lower end of the support column, and is crushed during connection and connected to the wiring unit. The mechanical quantity detection sensor characterized by being made . The semiconductor substrate has a structure in which a semiconductor substrate is sandwiched between an upper support substrate and a lower support substrate. The semiconductor substrate has an upper end bonded to the upper support substrate and a lower end bonded to the lower support substrate, and has an opening. A sensor unit including a frame part, a weight body disposed in the opening, and a connection part that flexibly connects the weight body and the frame part; The support substrate has an upper electrode on its lower surface, the lower support substrate has a lower electrode on its upper surface, and the upper electrode and the sensor unit, and the lower electrode and the sensor unit have capacitive elements vertically. A mechanical quantity detection sensor formed,
The semiconductor substrate includes a support column made of silicon that is disposed in the frame and connects the upper support substrate and the lower support substrate and contains impurities, and the upper support substrate is provided on at least one of an upper end and a lower end of the support column. Alternatively, the lower support substrate and the support column are connected, and a connecting portion made of a conductive material made of any one of Al, Au, Pt, and Cu is provided.
The upper electrode and the lower electrode include a detection electrode that detects a change in electrostatic capacitance of a capacitive element, and a drive electrode that vibrates and drives the weight body in the vertical direction, and the upper electrode or the lower electrode Each has a wiring portion that is integrated and extended with the electrode, and the column is connected to the wiring portion by the connecting portion, and is connected to the upper supporting substrate and / or the lower supporting substrate. And
The strut has a notch with respect to either the upper end or the lower end of the strut and the side of the strut, and the connecting portion is disposed in the notch,
A part of the connecting portion protrudes from a side surface of the support column. At least one of the upper support substrate and the lower support substrate has a wiring terminal penetrating in the thickness direction of the substrate,
The wiring portion is directly connected to the wiring terminal,
Furthermore, the said connection part covers the whole surface of the said terminal for wiring, and the said wiring part, The mechanical quantity sensor of Claim 1 or 2 characterized by the above-mentioned.

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