Source: https://patents.google.com/patent/JP2013181884A/en
Timestamp: 2020-02-20 02:10:13
Document Index: 265143816

Matched Legal Cases: ['arts 5', 'arts 5', 'art 5', 'arts 7', 'arts 8', 'art 55', 'art 5', 'art 5', 'arts 5', 'arts 5', 'arts 5', 'arts 5', 'arts 5', 'arts 52', 'arts 5', 'art) 25', 'art 5', 'art 5', 'art 6', 'art 5', 'art 6', 'art 40', 'art 40', 'art 2', 'art 3', 'art 3']

JP2013181884A - Electrostatic capacitance sensor - Google Patents
Electrostatic capacitance sensor Download PDF
JP2013181884A
JP2013181884A JP2012046640A JP2012046640A JP2013181884A JP 2013181884 A JP2013181884 A JP 2013181884A JP 2012046640 A JP2012046640 A JP 2012046640A JP 2012046640 A JP2012046640 A JP 2012046640A JP 2013181884 A JP2013181884 A JP 2013181884A
JP2012046640A
伸行 茨
慎一 岸本
英喜 上田
全史 岡田
昌利 野村
淳 荻原
2012-03-02 Application filed by Panasonic Corp, パナソニック株式会社 filed Critical Panasonic Corp
2012-03-02 Priority to JP2012046640A priority Critical patent/JP2013181884A/en
2013-09-12 Publication of JP2013181884A publication Critical patent/JP2013181884A/en
A capacitive sensor capable of further improving detection accuracy is obtained.
An electrostatic capacitance sensor includes a semiconductor substrate, a first fixing plate is bonded to one surface of the semiconductor substrate, and a second fixing plate is bonded to the other surface of the semiconductor substrate. The space part S is formed by joining 3. The electrostatic capacitance sensor 1 is provided with static electricity suppression means 70 that suppresses generation of static electricity in the space S.
The present invention relates to a capacitive sensor.
2. Description of the Related Art Conventionally, a capacitive sensor is known in which an upper fixed plate and a lower fixed plate are joined to front and back surfaces of a semiconductor substrate including a movable body having a movable electrode and a frame portion (for example, a patent) Reference 1).
In this patent document 1, the fixed electrode spaced apart so that it may oppose the movable electrode of a movable body is formed in the upper stationary plate. In addition, the center of the movable body is supported by a beam, and the center of gravity on both ends of the movable body is asymmetrical with respect to the central portion supported by the beam, so that the movable body is shaken when acceleration is input. I try to move it.
Then, the magnitude of the input acceleration is detected by calculating the difference in capacitance that changes between both ends of the movable electrode and the fixed electrode when the movable body swings.
JP 2010-127648 A
However, in the conventional technique, the movable body is formed using an SOI substrate in which a buried insulating layer made of SiO 2 is interposed between a silicon active layer made of Si and a support substrate made of Si. The fixed plate on which the fixed electrode is formed is formed using glass. This glass is an insulator and is electrically unstable. For this reason, a potential difference may occur between the fixed plate and the movable body. As described above, when a potential difference is generated between the fixed plate and the movable body, the posture of the movable body may be changed by static electricity generated by the potential difference.
As described above, in the conventional technique, there is a possibility that the detection accuracy of the capacitance type sensor is lowered.
Therefore, an object of the present invention is to obtain a capacitance type sensor that can suppress a decrease in detection accuracy.
According to a first aspect of the present invention, there is provided a first fixed plate in which a fixed electrode is formed on one surface of a semiconductor substrate on which a movable body having a movable electrode is formed. And a space portion is formed by bonding a second fixing plate to the other surface of the semiconductor substrate. The capacitance sensor includes a static electricity in the space portion. The gist of the invention is that a static electricity suppressing means for suppressing the occurrence of the above is provided.
The second feature of the present invention is that the static electricity suppressing means is at least one of a portion other than a portion of the inner surface of the first fixed plate where the fixed electrode is formed and an inner surface of the second fixed plate. The metal film is electrically insulated from the fixed electrode and electrically connected to the movable body.
The gist of the third feature of the present invention is that the movable body is formed without using an insulator.
A fourth feature of the present invention is summarized in that the metal film is formed in a recess formed on the inner surface of the first fixing plate or the inner surface of the second fixing plate.
The fifth feature of the present invention is summarized as that the second fixing plate is a conductor.
The sixth feature of the present invention is summarized in that a recess is formed on the inner surface of the second fixing plate.
The seventh feature of the present invention is summarized in that the static electricity suppressing means is a static electricity suppressing material filled in the space portion.
The eighth feature of the present invention is summarized in that the static electricity suppressing material is ionized air or inert gas.
A ninth feature of the present invention is summarized in that the capacitive sensor is formed with a communication path that communicates the space portion with an external space.
According to the present invention, the electrostatic capacitance sensor is provided with the static electricity suppressing means for suppressing the generation of static electricity in the space. Therefore, it is possible to suppress unexpected fluctuations in the posture of the movable body, and it is possible to suppress a decrease in detection accuracy of the capacitive sensor.
It is a disassembled perspective view which shows the electrostatic capacitance type sensor concerning 1st Embodiment of this invention. 1 is a plan view showing a semiconductor substrate according to a first embodiment of the present invention. It is a back view which shows the semiconductor substrate concerning 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is operation | movement explanatory drawing of an electrostatic capacitance type sensor. It is a system block diagram of an electrostatic capacitance type sensor. It is explanatory drawing which shows typically the detection principle of the acceleration applied to the X direction. It is explanatory drawing which shows typically the detection principle of the acceleration applied to the Z direction. It is explanatory drawing which shows the output calculating type | formula of an electrostatic capacitance type sensor in a table format. It is explanatory drawing which illustrates typically a response | compatibility with the semiconductor substrate of the fixed electrode and auxiliary electrode of the electrostatic capacitance type sensor concerning 1st Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 1st Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 2nd Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 3rd Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 4th Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 5th Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 6th Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 7th Embodiment of this invention. It is sectional drawing which shows typically the electrostatic capacitance type sensor concerning 8th Embodiment of this invention.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Below, an acceleration sensor is illustrated as an electrostatic capacitance type sensor. Further, the side of the weight portion on which the movable electrode is formed is defined as the surface side of the semiconductor substrate. Then, the short direction of the semiconductor substrate will be described as the X direction, the longitudinal direction of the semiconductor substrate as the Y direction, and the thickness direction of the semiconductor substrate as the Z direction.
Moreover, the same component is contained in the following several embodiment. Therefore, in the following, common reference numerals are given to those similar components, and redundant description is omitted.
As shown in FIG. 1, an acceleration sensor (capacitance sensor) 1 according to this embodiment includes a silicon substrate (semiconductor substrate) 4 on which a semiconductor element device is formed. The first insulating substrate (first fixing plate) 2 and the second insulating substrate (first fixing plate) 2 made of glass bonded to the front surface (one surface) 4a and the back surface (other surface) 4b of the silicon substrate 4, respectively. 2 fixing plates) 3. In this embodiment, the silicon substrate 4 is bonded to the first insulating substrate 2 and the second insulating substrate 3 by anodic bonding.
The lower surface (inner surface) 2a of the first insulating substrate 2 is provided with fixed electrodes 21a, 21b and 22a, 22b corresponding to the installation areas of the weight portions (movable bodies) 5, 6, respectively.
Further, on the upper surface (inner surface) 3 a of the second insulating substrate 3, adhesion preventing films 31 and 32 are formed in regions corresponding to the installation regions of the weight parts 5 and 6, respectively. The adhesion preventing films 31 and 32 can be formed of the same material as the fixed electrodes 21a and 21b and 22a and 22b, for example.
The silicon substrate 4 has a gap 43 with respect to the frame portion 40 in which two frame portions 40a and 40b are arranged in parallel in the Y direction (longitudinal direction of the silicon substrate 4) and the inner peripheral surface of the frame portions 40a and 40b. The weight portions 5 and 6 disposed in the frame portions 40a and 40b in a state and a pair of beam portions 7a and 7b and 8a and 8b that rotatably support the weight portions 5 and 6 with respect to the frame portion 40, respectively. And movable electrodes 5a and 6a formed on the surfaces (one surface) of the weight portions 5 and 6.
In this embodiment, a rectangular SOI substrate in which a buried insulating layer 112 made of SiO 2 is interposed between a silicon active layer 111 made of Si and a support substrate 113 made of Si is used as the silicon substrate 4. . The longitudinal side of the silicon substrate 4 is about 2 to 4 mm, the thickness is about 0.4 to 0.6 mm, the thickness of the silicon active layer 111 is about 10 to 20 μm, and the thickness of the buried insulating layer 112 The thickness is about 0.5 μm.
In this embodiment, the frame portion 40 extends in a substantially rectangular outer frame portion 41 as viewed from the Z direction (thickness direction of the silicon substrate 4) and the X direction (short direction of the silicon substrate 4). And a central frame portion 42 that connects substantially the central portion of the outer frame portion 41 in the Y direction (longitudinal direction of the silicon substrate 4).
As shown in FIGS. 3 and 4, the weight portions 5, 6 are integrally formed with recesses 55, 65 opening on one surface (back surface) and solid portions 53, 63 excluding the recesses 55, 65. That is, by forming concave portions 55 and 65 opened on one surface (rear surface) on the weight portions 5 and 6, the thick portions 53 and 63 and the thin thin portions 54 and 64 are formed on the weight portions 5 and 6. Forming.
As shown in FIG. 4, the solid portions 53 and 63 are formed in a rectangular shape as viewed from the back side, and in the solid portions 53 and 63, diagonal groove portions 56 and 66 are formed on the movable electrode 5 a. , 6a.
Further, the recesses 55 and 65 are formed in a rectangle having side walls on four sides, and reinforcing walls 57 and 67 are provided in the interior perpendicular to the movable electrodes 5a and 6a.
In the present embodiment, the recess 55 is formed on one side in the X direction (the back side in FIG. 1) with respect to the rotation axis A1 described later, and the recess 65 is on the other side in the X direction with respect to the rotation axis A2 described later. It is formed on the front side of FIG.
The beam portions 7a, 7b and 8a, 8b are formed in the silicon active layer 111 of the SOI substrate (silicon substrate 4), deep etching is performed using the embedded insulating layer 112 of the SOI substrate as an etching stop, and further the embedded insulating layer It is formed by selectively removing 112.
The beam portions 7a and 7b are respectively positioned on two opposite sides of the surface of the weight portion 5 (movable electrode 5a). When the beam portions 7a and 7b are twisted, the movable electrode 5a causes the beam portions 7a and 7b to be mutually connected. The connecting straight line swings as a rotation axis (axis) A1. Similarly, the beam portions 8a and 8b are respectively located on two opposite sides of the surface of the weight portion 6 (movable electrode 6a), and the movable electrode 6a has a rotation axis (axis) connecting the beam portions 8a and 8b to each other. ) Swings as A2.
Further, in the present embodiment, the weight parts 5 and 6 have a thickness of the weight part 5 in a region sharing one side of the two sides not connected to the beam parts 7a and 7b and the beam parts 8a and 8b. , 6 has a stepped portion 5b, 6b in which the plane pattern is thinner than other portions. The step portions 5b and 6b are formed by selectively removing the silicon active layer 111 of the silicon substrate 4. The beam portions 7a and 7b and the beam portions 8a and 8b are located at the midpoints of the two sides of the surface excluding the step portions 5b and 6b of the weight portions 5 and 6, respectively.
Further, in the present embodiment, the weight portion 5 and the weight portion 6, the beam portion 7a and the beam portion 8a, and the beam portion 7b and the beam portion 8b are respectively connected to one point of the silicon substrate 4 (a line connecting the beam portion 7b and the beam portion 8b). It is arranged so as to be point symmetric with respect to the midpoint of the minute).
By the way, in this embodiment, as shown in FIG. 4, the recessed part 55 is formed in the one side of rotating shaft (axis | shaft) A1 in the back side of the weight part 5, and it is made for the gravity center of the weight part 5 to shift to the other side. ing. Similarly, a recess 65 is formed on the other side (the other side of the rotation axis (axis) A2) opposite to the one side where the recess 55 is provided on one weight 5 on the back side of the weight 6, The center of gravity of the weight portion 6 is shifted to one side. When acceleration is applied in the X direction or the Z direction, the operation is performed as shown in FIG. 5 so that the acceleration a applied in the X direction and the Z direction can be detected (see FIGS. 7 and 8). .
At this time, for example, referring to FIG. 4 as an example of one of the weight parts 5, both the weight parts 5 and 6 are perpendicular to the surface (movable electrode 5a) from the center of gravity G on the side where the recess 55 is not formed. The angle θ formed by the straight line connecting the center of gravity G and the rotation axis (axis) A1 is set to be approximately 45 degrees. The same applies to the other weight portion 6, but in this case, as described above, the position of the center of gravity exists on the opposite side of the center of gravity G of the weight portion 5 across the rotation axis (axis) A 2. Become. If the center of gravity G is arranged in this way, the detection sensitivities in the X direction and the Z direction are equivalent, so that the detection sensitivities in the respective directions can be made substantially the same.
In addition, relatively shallow gaps G1 and G2 are formed on the bonding surface between the silicon substrate 4 and the first insulating substrate 2 and the second insulating substrate 3, respectively. The operability of the parts (movable electrodes 5a, 6a) 5, 6 is ensured. That is, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4 a of the silicon substrate 4, and the second insulating substrate (second surface) 4 b is bonded to the back surface (other surface) 4 b of the silicon substrate 4. The fixing plate 3) is joined to form the space S. By forming this space portion S, the operability of the weight portions (movable electrodes 5a, 6a) 5, 6 is secured.
The gap G2 on the back side of the silicon substrate 4 is formed by anisotropic etching using an alkaline wet anisotropic etching solution (for example, KOH (potassium hydroxide aqueous solution), TMAH (tetramethyl ammonium hydroxide aqueous solution), etc.). Thus, the silicon substrate 4 can be formed by removing a part thereof. At this time, it is preferable to form the concave portions 55 and 65 described above at the same time.
In addition, the gap 43 and the gap 44 are formed by performing a vertical etching process by reactive ion etching (RIE) or the like. As reactive ion etching, for example, ICP processing by an etching apparatus provided with inductively coupled plasma (ICP) can be used.
Further, projections for preventing the weight parts 5 and 6 from directly colliding with the fixed electrodes 21a, 21b, 22a and 22b of the first insulating substrate 2 are provided at the four corners of the surface of the weight parts 5 and 6. 51 and 61 are projected.
Similarly, at the four corners of the back surface of the weight parts 5 and 6, the protrusion parts 52 and 6 for preventing the weight parts 5 and 6 from directly colliding with the adhesion preventing films 31 and 32 of the second insulating substrate 3. 62 is protrudingly provided.
Further, in the present embodiment, the outer frame portion 41 is formed with a wide X-direction one end (the lower side in FIG. 2), and the weight portions 5, 6 are disposed on the X-direction one end of the outer frame portion 41. Clearances 44, 44 are formed so as to be continuous with the clearances 43, 43 where the In addition, two electrode bases 9 are arranged with two gaps 44 therebetween.
Detection electrodes 10a, 10b, 11a, and 11b made of metal films are provided on the surface of the electrode table 9, respectively.
The electrode table 9 is disposed separately from the frame portion 40 and the weight portions 5 and 6, and the upper and lower surfaces are fixed by the first insulating substrate 2 and the second insulating substrate 3. Further, a common electrode 12 wired outside the acceleration sensor 1 is provided at the center in the Y direction on the surface of the outer frame portion 41, and the frame portion 40 takes a common potential by the common electrode 12.
As described above, the fixed electrodes 21a, 21b and 22a, 22b corresponding to the installation areas of the weight portions 5, 6 are provided on the lower surface of the first insulating substrate 2, respectively. These fixed electrodes 21a, 21b and 22a, 22b are formed to have substantially the same shape and the same area.
The fixed electrodes 21a and 21b are spaced apart from each other with a straight line (rotation axis A1) connecting the beam portions 7a and 7b as a boundary line. Similarly, the fixed electrodes 22a and 22b are spaced apart from each other with a straight line (rotation axis A2) connecting the beam portions 8a and 8b as a boundary line. In this embodiment, each fixed electrode 21a, 21b and 22a, 22b is formed by vapor-depositing aluminum (Al) on the first insulating substrate 2 by a sputtering method, a CVD method or the like.
The fixed electrodes 21a and 21b are electrically connected to the detection electrodes 10a and 10b, respectively, and the fixed electrodes 22a and 22b are electrically connected to the detection electrodes 11a and 11b, respectively.
Specifically, the fixed electrodes 21a, 21b and 22a, 22b are led out toward the fixed electrode base 9 on which the detection electrodes 10a, 10b and 11a, 11b to which the fixed electrodes 21a, 21b, 22b are respectively connected are formed. Part) 25 is provided.
Each fixed electrode base 9 is formed with an aluminum conductive layer (semiconductor substrate side metal contact portion) 13 with which a lead wire (fixed electrode side metal contact portion) 25 contacts. In the present embodiment, a step 9a is provided on the other end side in the X direction of each fixed electrode base 9 (upper side in FIG. 2: weight side), and the lower surface of the step 9a, that is, the detection electrodes 10a, 10b and 11a. , 11b is formed at a position lower than the surface on which the surface is formed (semiconductor substrate side metal contact portion) 13 (see FIG. 4).
The lead wire (fixed electrode side metal contact portion) 25 and the conductive layer (semiconductor substrate side metal contact portion) 13 are crushed together when the silicon substrate 4 and the first insulating substrate 2 are anodic bonded. Being touched.
Thus, the fixed electrodes 21a, 21b and 22a, 22b are electrically connected to the detection electrodes 10a, 10b and 11a, 11b.
The detection electrodes 10a, 10b and 11a, 11b are separated from each other and are separated from the frame portion 40 and the weight portions 5, 6, respectively. Therefore, the detection electrodes are insulated from each other, and the parasitic capacitance of each detection electrode, Crosstalk between the detection electrodes can be reduced, and highly accurate capacitance detection can be performed.
In addition, through holes 23 are respectively formed by sandblasting or the like in portions corresponding to the electrode base 9 of the first insulating substrate 2, and in portions corresponding to the common electrode 12 of the first insulating substrate 2. The through holes 24 are respectively formed by sandblasting or the like. The detection electrodes 10a, 10b, 11a, and 11b are exposed and wired to the outside through the through holes 23, respectively, and the common electrode 12 is exposed and wired to the outside through the through holes 24, respectively. Thus, the potentials of the fixed electrodes 21a, 21b, 22a, 22b and the movable electrodes 5a, 6a can be extracted to the outside.
In the acceleration sensor 1 configured as described above, when the acceleration indicated by the arrow a in FIG. 5 is applied, both the weight portions 5 and 6 swing, and both ends of the weight portions 5 and 6 and the fixed electrode are moved. The gap d between 21a, 21b and 22a, 22b changes, and the capacitances C1, C2, C3, C4 between these gaps d change. In addition, in FIG. 5, one weight part 5 is illustrated.
The capacitance C at this time is known to be C = ε × S / d (ε: dielectric constant, S: electrode area, d: gap), and the electrostatic capacity increases as the gap d increases from this equation. The capacitance C decreases, and the capacitance C increases as the gap d decreases.
Then, as shown in the system configuration of FIG. 6, the acceleration sensor 1 sends the detected electrostatic capacitances C1, C2, C3, and C4 to an arithmetic circuit 100 configured by, for example, an ASIC, and accelerates in the X direction. Further, acceleration in the Z direction is obtained, and data indicating the acceleration is output. At this time, an arithmetic expression executed by the arithmetic circuit 100 is shown in FIG. 9, and C1 obtained by applying the acceleration a in the X direction shown in FIG. 7 and applying the acceleration a in the Z direction shown in FIG. , C2, C3, and C4 determine the direction of acceleration a. Note that a parameter C0 in the following expression indicates the capacitance between the weights 5 and 6 and the fixed electrodes 21a and 21b and 22a and 22b in a state where the acceleration a is not applied.
When acceleration a is applied in the + X direction (see FIG. 7), both the weight portions 5 and 6 swing in the same direction, so C1 = C0 + ΔC, C2 = C0−ΔC, C3 = C0 + ΔC, C4 = C0−ΔC. When the acceleration a is applied in the −X direction, the swinging directions of the weight portions 5 and 6 are opposite to the + direction, so that C1 = C0−ΔC, C2 = C0 + ΔC, and C3 = C0−. ΔC, C4 = C0 + ΔC.
On the other hand, when acceleration a is applied in the + Z direction (see FIG. 8), both weight portions 5 and 6 swing in opposite directions, so that C1 = C0−ΔC, C2 = C0 + ΔC, C3 = C0 + ΔC, C4 = C0−ΔC. When the acceleration a is applied in the −Z direction, the swinging directions of the weights 5 and 6 are opposite to the + direction, so C1 = C0 + ΔC, C2 = C0−ΔC, and C3 = C0−. ΔC, C4 = C0 + ΔC.
Therefore, the capacitance difference CA (= C1-C2) between the one weight portion 5 and the fixed electrodes 21a and 21b is + 2ΔC in the + X direction, −2ΔC in the −X direction, −2ΔC in the + Z direction, − + 2ΔC in the Z direction. Further, the difference in capacitance CB (= C3−C4) between the other weight portion 6 and the fixed electrodes 22a and 22b is + 2ΔC in the + X direction, −2ΔC in the −X direction, + 2ΔC and −Z in the + Z direction. -2ΔC in the direction.
Here, the output in the X direction can be obtained as the sum of both differences CA and CB, and the output in the Z direction can be obtained as the difference between both differences CA and CB. As a result, the output in the X direction becomes + 4ΔC when the acceleration a in the + X direction is applied, and becomes −4ΔC when the acceleration a in the −X direction is applied. The output in the Z direction is −4ΔC when the acceleration a in the + Z direction is applied, and is + 4ΔC when the acceleration a in the −Z direction is applied.
By the way, as shown in FIG. 1, the acceleration sensor 1 of the present embodiment includes a first acceleration sensor unit having one weight part 5 and a second acceleration sensor unit having the other weight part 6. Arranged in the same chip plane, each acceleration sensor unit is arranged in a state of being relatively rotated by 180 degrees. Thus, the gravity center positions of one weight part 5 in the first acceleration sensor alone and the other weight part 6 in the second acceleration sensor alone are opposite to each other with respect to the rotation axes (axis) A1 and A2. The acceleration a in the X direction and the Z direction can be detected.
Here, in the present embodiment, the electrostatic capacitance sensor 1 is provided with static electricity suppression means 70 that suppresses generation of static electricity in the space S.
Specifically, as shown in FIG. 10, a metal film 26 is formed on a portion of the lower surface (inner surface) 2a of the first insulating substrate 2 other than the portion where the fixed electrodes 21a, 21b and 22a, 22b are formed. The metal film 26 is used as static electricity suppression means 70.
The metal film 26 is provided outside the pair of fixed electrodes 21a and 21b in the X direction, and is in contact with the frame portion 40 through the wiring 26a. That is, the metal film 26 is electrically connected to the weight part (movable body) 5 via the wiring 26 a and the frame part 40. On the other hand, the metal film 26 is not in contact with the fixed electrodes 21a and 21b, and is electrically insulated from the fixed electrodes 21a and 21b. Although not shown, a similar metal film 26 is also formed on the weight 6 side.
Furthermore, in the present embodiment, the adhesion preventing films (metal films) 31 and 32 formed on the upper surface (inner surface) 3 a of the second insulating substrate 3 are also used as the static electricity suppressing means 70. That is, the adhesion preventing films (metal films) 31 and 32 formed so as to face the back surfaces of the weight parts (movable bodies) 5 and 6 are formed on the weight parts (movable bodies) 5 and 6 via the wiring 26 a and the frame part 40. Electrically connected. The adhesion preventing films (metal films) 31 and 32 are also electrically insulated from the fixed electrodes 21a and 21b and 22a and 22b.
As described above, in the present embodiment, the electrostatic capacitance sensor 1 is provided with the static electricity suppression means 70 that suppresses the generation of static electricity in the space S.
Specifically, a portion other than the portion where the fixed electrodes 21a, 21b and 22a, 22b are formed on the lower surface (inner surface) 2a of the first insulating substrate (first fixing plate) 2 and the second insulating substrate. A metal film (including an adhesion preventing film) 26 was formed on at least one (both in the present embodiment) of the upper surface (inner surface) 3a of the (second fixing plate) 3. Thus, the facing area between the surfaces of the weight parts (movable bodies) 5 and 6 and the lower surface (inner surface) 2a of the first insulating substrate 2 and the back surfaces of the weight parts (movable bodies) 5 and 6 and the second insulating substrate. 3 is reduced in the area facing the upper surface (inner surface) 3a. Then, the metal film 26 and the adhesion preventing films (metal films) 31 and 32 that reduce the facing area (exposed portion area) are electrically connected to the weight parts (movable bodies) 5 and 6 and the weight parts (movable body). 5 and 6 are set to the same potential.
In this way, by forming the metal film 26 having the same potential as the weight portions (movable bodies) 5 and 6 at the portions facing the weight portions (movable bodies) 5 and 6, electrically unstable glass (insulation) The area facing the body is reduced. Therefore, between the surface of the weight parts (movable bodies) 5 and 6 and the lower surface (inner surface) 2 a of the first insulating substrate 2, the back surface of the weight parts (movable bodies) 5 and 6 and the second insulating substrate 3. It is possible to suppress the occurrence of a potential difference with respect to the upper surface (inner surface) 3a. As a result, the potential difference between the weight portions (movable bodies) 5 and 6 and the first insulating substrate (first fixed plate) 2 or the weight portions (movable bodies) 5 and 6 and the second insulating substrate ( It is possible to suppress the generation of static electricity due to the potential difference with the second fixed plate 3), and to suppress unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6. It can suppress that the detection accuracy of the capacitive sensor 1 falls.
At this time, since the metal film 26 and the adhesion preventing films (metal films) 31 and 32 are electrically insulated from the fixed electrodes 21a and 21b and 22a and 22b, they are fixed to the weight parts (movable bodies) 5 and 6. A potential difference can be generated between the electrodes 21a, 21b and 22a, 22b.
Therefore, it can suppress that the metal film 26 and the adhesion prevention films (metal films) 31 and 32 impair the function as a sensor. That is, it is possible to suppress a decrease in detection accuracy of the capacitive sensor 1 due to the formation of the metal film 26 and the adhesion preventing films (metal films) 31 and 32.
The acceleration sensor 1A according to the present embodiment has basically the same configuration as the acceleration sensor 1 of the first embodiment.
That is, in the acceleration sensor 1A, the first insulating substrate (first fixing plate) 2 is bonded to the front surface (one surface) 4a of the silicon substrate 4A, and the second insulating material is connected to the back surface (other surface) 4b of the silicon substrate 4A. The space portion S is formed by bonding the conductive substrate (second fixing plate) 3.
And the static electricity suppression means 70 which suppresses that static electricity arises in the space part S is provided.
Also in this embodiment, the metal film (including the adhesion preventing films 31 and 32 and the wiring 26a) 26 is used as the static electricity suppressing means 70.
Here, the acceleration sensor 1A according to the present embodiment is mainly different from the acceleration sensor 1 of the first embodiment in that the weight portions (movable bodies) 5 and 6 are formed without using an insulator.
In this embodiment, as shown in FIG. 12, the weight portions (movable bodies) 5 and 6 and the frame portion 40 are formed using a silicon substrate (semiconductor substrate) 4A made of Si without using an SOI substrate. .
Thus, by forming the weight parts (movable bodies) 5 and 6 without using an insulator, the structure of the weight parts (movable bodies) 5 and 6 is made not to be electrically divided.
Also according to this embodiment described above, the same operations and effects as those of the first embodiment can be achieved.
Further, according to the present embodiment, the weight portions (movable bodies) 5 and 6 are formed without using an insulator. Thus, by forming the weight parts (movable bodies) 5 and 6 without using an insulator, the structure of the weight parts (movable bodies) 5 and 6 can be made not to be electrically divided. It is possible to suppress the potential difference between the upper and lower portions (movable bodies) 5 and 6. Therefore, it is possible to suppress the generation of static electricity due to the potential difference generated above and below the weight parts (movable bodies) 5 and 6, and to suppress unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6. become able to. As a result, it is possible to suppress a decrease in detection accuracy of the capacitive sensor 1A.
The acceleration sensor 1B according to the present embodiment basically has the same configuration as the acceleration sensor 1A of the second embodiment.
That is, in the acceleration sensor 1B, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4A, and the second insulating material is bonded to the back surface (other surface) 4b of the silicon substrate 4A. The space portion S is formed by bonding the conductive substrate (second fixing plate) 3.
Further, the weight portions (movable bodies) 5 and 6 are formed without using an insulator.
Here, the acceleration sensor 1B according to the present embodiment is mainly different from the acceleration sensor 1A of the second embodiment in that it is formed on the lower surface (inner surface) 2a of the first insulating substrate (first fixing plate) 2. The metal film 26 is formed in the recessed portion 2b.
In the present embodiment, as shown in FIG. 13, a portion other than the portion where the fixed electrodes 21a, 21b and 22a, 22b are formed on the lower surface (inner surface) 2a of the first insulating substrate (first fixed plate) 2. A recess 2b is formed in the recess, and a metal film 26 is formed in the recess 2b. In addition, it is preferable that the depth of the recessed part 2b shall be 3 micrometers or more.
Thus, by forming the metal film 26 in the recess 2b, the distance (first insulation) between the weight parts (movable bodies) 5 and 6 and the first insulating substrate (first fixed plate) 2 is obtained. The distance between the weight portions 5 and 6 at a portion other than the portion where the fixed electrodes 21a and 21b and 22a and 22b of the conductive substrate 2 are formed is increased.
Also according to this embodiment described above, the same operations and effects as those of the second embodiment can be achieved.
Further, according to the present embodiment, the metal film 26 is formed in the recess 2 b formed on the lower surface (inner surface) 2 a of the first insulating substrate (first fixing plate) 2. Therefore, the distance between the weight parts (movable bodies) 5 and 6 and the first insulating substrate (first fixed plate) 2 (the fixed electrodes 21a and 21b and 22a and 22b of the first insulating substrate 2 are It is possible to increase the distance between the weight portions 5 and 6 in a portion other than the formed portion. Thus, by increasing the distance to the weight parts (movable bodies) 5 and 6, the influence of static electricity on the weight parts (movable bodies) 5 and 6 can be further reduced. As a result, unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6 can be suppressed, and the detection accuracy of the capacitive sensor 1B can be prevented from being lowered. .
The acceleration sensor 1C according to the present embodiment has basically the same configuration as the acceleration sensor 1A of the second embodiment.
That is, in the acceleration sensor 1C, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4A, and the second fixing is performed on the back surface (other surface) 4b of the silicon substrate 4A. The space S is formed by joining the plates 3C.
Here, the difference between the acceleration sensor 1C according to the present embodiment and the acceleration sensor 1A according to the second embodiment is that the second fixing plate 3C is made of a conductor.
In the present embodiment, as shown in FIG. 14, the second fixing plate 3C is formed using a silicon substrate made of Si. Since the second fixed plate 3C is electrically connected to the silicon substrate 4A when bonded to the silicon substrate 4A, the upper surface (inner surface) 3aC of the second fixed plate 3C is a weight portion (movable body) 5. , 6 are connected to the same potential.
Therefore, in the present embodiment, no adhesion preventing film is formed on the upper surface (inner surface) 3aC of the second fixing plate 3C.
In other words, in the present embodiment, the second fixed plate 3C and the lower surface (inner surface) 2a of the first insulating substrate 2 are formed at portions other than the portions where the fixed electrodes 21a, 21b and 22a, 22b are formed. The metal film (including the wiring 26a) 26 is used as the static electricity suppressing means 70.
Further, according to the present embodiment, the second fixing plate 3C is constituted by a silicon substrate that is a conductor. Therefore, the second fixed plate 3C is electrically connected to the silicon substrate 4A when bonded to the silicon substrate 4A, and the upper surface (inner surface) 3aC of the second fixed plate 3C is connected to the weight portion (movable body) 5. , 6 can be electrically connected to each other. Therefore, it is not necessary to form an adhesion preventing film (metal film) on the upper surface (inner surface) 3aC of the second fixing plate 3C, and the manufacturing process can be simplified.
The acceleration sensor 1D according to the present embodiment basically has the same configuration as the acceleration sensor 1A of the second embodiment.
That is, in the acceleration sensor 1D, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4A, and the second insulating material is bonded to the back surface (other surface) 4b of the silicon substrate 4A. The space portion S is formed by bonding the conductive substrate (second fixing plate) 3.
Here, the acceleration sensor 1D according to the present embodiment is mainly different from the acceleration sensor 1A of the second embodiment in that the anti-adhesion films (metal films) 31 and 32 are disposed on the second insulating substrate (second film). It is in the point formed in the recessed part 3b formed in the upper surface (inner surface) 3a of the fixing plate 3.
In this embodiment, as shown in FIG. 15, a recess 3b is formed on the upper surface (inner surface) 3a of the second insulating substrate (second fixing plate) 3, and an adhesion preventing film (metal film) is formed on the recess 3b. 31 and 32 are formed. In addition, it is preferable that the depth of the recessed part 3b shall be 3 micrometers or more.
In this way, by forming the adhesion preventing films (metal films) 31 and 32 in the recess 3b, the space between the weight parts (movable bodies) 5 and 6 and the second insulating substrate (second fixed plate) 3 is achieved. The distance is increased.
Further, according to the present embodiment, the adhesion preventing films (metal films) 31 and 32 are formed in the recess 3b formed on the upper surface (inner surface) 3a of the second insulating substrate (second fixing plate) 3. . Therefore, the distance between the weight parts (movable bodies) 5 and 6 and the second insulating substrate (second fixed plate) 3 can be increased. Thus, by increasing the distance to the weight parts (movable bodies) 5 and 6, the influence of static electricity on the weight parts (movable bodies) 5 and 6 can be further reduced. As a result, unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6 can be suppressed, and the detection accuracy of the capacitive sensor 1D can be prevented from being lowered. .
The acceleration sensor 1E according to the present embodiment basically has the same configuration as the acceleration sensor 1C of the fourth embodiment.
That is, in the acceleration sensor 1E, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4A, and the second fixing is performed on the back surface (other surface) 4b of the silicon substrate 4A. The space S is formed by joining the plates 3C.
Also in the present embodiment, a metal film (wiring 26a) formed on a portion other than the portion where the fixed electrodes 21a, 21b and 22a, 22b are formed on the lower surface (inner surface) 2a of the silicon substrate 3C and the first insulating substrate 2. 26) is used as static electricity suppression means 70.
Here, the acceleration sensor 1E according to the present embodiment is mainly different from the acceleration sensor 1C of the fourth embodiment in that a recess 3bC is formed on the upper surface (inner surface) 3aC of the second fixing plate 3C formed of a conductor. It is in the point.
In the present embodiment, as shown in FIG. 16, a recess 3bC is formed over almost the entire area of the upper surface (inner surface) 3aC of the second fixed plate 3C facing the back surfaces of the weight portions (movable bodies) 5 and 6. Yes. The depth of the recess 3bC is preferably 3 μm or more.
Also according to this embodiment described above, the same operations and effects as those of the fourth embodiment can be obtained.
Further, according to the present embodiment, the recess 3bC is formed on the upper surface (inner surface) 3aC of the second fixing plate 3C formed of a conductor. Therefore, the distance between the weight parts (movable bodies) 5 and 6 and the second fixed plate 3C can be increased. Thus, by increasing the distance to the weight parts (movable bodies) 5 and 6, the influence of static electricity on the weight parts (movable bodies) 5 and 6 can be further reduced. As a result, unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6 can be suppressed, and the detection accuracy of the capacitive sensor 1E can be suppressed from decreasing. .
The acceleration sensor 1F according to the present embodiment basically has the same configuration as the acceleration sensor 1 of the first embodiment.
That is, in the acceleration sensor 1F, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4, and the second insulating material is connected to the back surface (other surface) 4b of the silicon substrate 4. The space portion S is formed by bonding the conductive substrate (second fixing plate) 3.
Here, the acceleration sensor 1F according to the present embodiment is mainly different from the acceleration sensor 1 of the first embodiment in that a static electricity suppressing material filled in the space S is used as the static electricity suppressing means 70. .
In the present embodiment, air ionized using a known ionizer or an inert gas such as nitrogen or argon is used as a static electricity suppressing material, and the space S is filled with ionized air or the like.
In this way, by filling the space portion S with ionized air or the like, the influence of static electricity on the weight portions (movable bodies) 5 and 6 can be further reduced. As a result, unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6 can be suppressed, and the detection accuracy of the capacitive sensor 1F can be prevented from being lowered. .
Therefore, according to the present embodiment, the metal film is formed on a portion of the lower surface (inner surface) 2a of the first insulating substrate (first fixing plate) 2 other than the portion where the fixed electrodes 21a, 21b and 22a, 22b are formed. Even if 26 is not formed, the influence of static electricity on the weight parts (movable bodies) 5 and 6 can be further reduced. Further, there is no need to provide the anti-adhesion films 31 and 32 with a function of suppressing the generation of static electricity, and there is an advantage that the acceleration sensor 1F can be easily manufactured.
The acceleration sensor 1G according to the present embodiment has basically the same configuration as the acceleration sensor 1F of the seventh embodiment.
That is, in the acceleration sensor 1G, the first insulating substrate (first fixing plate) 2 is bonded to the surface (one surface) 4a of the silicon substrate 4, and the second insulating material is connected to the back surface (other surface) 4b of the silicon substrate 4. The space portion S is formed by bonding the conductive substrate (second fixing plate) 3.
Also in this embodiment, as the static electricity suppressing means 70, the static electricity suppressing material filled in the space S is used. That is, by filling the space portion S with ionized air or the like, the influence of static electricity on the weight portions (movable bodies) 5 and 6 is further reduced.
Here, the acceleration sensor 1G according to the present embodiment is mainly different from the acceleration sensor 1F of the seventh embodiment in that the capacitive sensor 1G communicates the space portion S with the atmosphere (external space). 4c is formed.
In this embodiment, as shown in FIG. 18, the communication path 4c is formed in the lower part of the silicon substrate 4, and the space S is communicated with the atmosphere (external space).
Also according to this embodiment described above, the same operations and effects as those of the seventh embodiment can be achieved.
Moreover, according to this embodiment, the communication path 4c which connects the space part S to air | atmosphere (external space) was formed in the capacitive sensor 1G. In this way, by allowing the space portion S to communicate with the atmosphere (external space), wetting in the space portion S is promoted and the humidity in the space portion S can be increased. As a result, the static electricity in the space S can be released to the outside, and the influence of the static electricity received by the weight parts (movable bodies) 5 and 6 can be further reduced. As a result, unexpected fluctuations in the postures of the weight parts (movable bodies) 5 and 6 can be suppressed, and the detection accuracy of the capacitive sensor 1G can be suppressed from being lowered. .
For example, in each of the above embodiments, an acceleration sensor that detects acceleration in two directions of the X direction and the Z direction has been illustrated. However, one of the weight portions is arranged by being rotated 90 degrees in the XY plane, and the Y direction is added. Alternatively, an acceleration sensor that detects acceleration in three directions may be used.
Moreover, in each said embodiment, although the acceleration sensor was illustrated as an electrostatic capacitance type sensor, it is not restricted to this, This invention is applicable also to another electrostatic capacitance type sensor.
In addition, an embodiment in which the configurations described in the first to eighth embodiments are arbitrarily combined can be used.
Further, the specifications (shape, size, layout, etc.) of the weight portion, fixed electrode, and other details can be changed as appropriate.
1, 1A, 1B, 1C, 1D, 1E, 1F, 1G Acceleration sensor (capacitance sensor)
2 First insulating substrate (first fixing plate)
3 Second insulating substrate (second fixing plate)
3C Second fixing plate 4, 4A Silicon substrate (semiconductor substrate)
5,6 Weight (movable body)
5a, 6a Movable electrode 21a, 21b, 22a, 22b Fixed electrode 26 Metal film 31, 32 Anti-adhesion film (metal film)
70 Static electricity suppression measures
A first fixed plate on which a fixed electrode is disposed opposite to the movable electrode is bonded to one surface of a semiconductor substrate on which a movable body having a movable electrode is formed, A capacitive sensor in which a space is formed by joining a second fixed plate to a surface,
The capacitance type sensor is characterized in that the capacitance type sensor is provided with a static electricity suppressing means for suppressing generation of static electricity in the space portion.
The static electricity suppressing means is a metal film formed on at least one of a portion other than a portion where the fixed electrode is formed on an inner surface of the first fixed plate and an inner surface of the second fixed plate,
The capacitance type sensor according to claim 1, wherein the metal film is electrically insulated from the fixed electrode and electrically connected to the movable body.
The capacitive sensor according to claim 1, wherein the movable body is formed without using an insulator.
4. The capacitance according to claim 2, wherein the metal film is formed in a recess formed on an inner surface of the first fixed plate or an inner surface of the second fixed plate. 5. Type sensor.
The capacitive sensor according to claim 1, wherein the second fixing plate is a conductor.
The capacitive sensor according to claim 5, wherein a concave portion is formed on an inner surface of the second fixing plate.
The electrostatic capacity sensor according to any one of claims 1 to 6, wherein the static electricity suppressing means is a static electricity suppressing material filled in the space portion.
The electrostatic capacity sensor according to claim 7, wherein the static electricity suppressing material is ionized air or an inert gas.
The capacitive sensor according to any one of claims 1 to 8, wherein the capacitive sensor is formed with a communication path that communicates the space portion with an external space.
JP2012046640A 2012-03-02 2012-03-02 Electrostatic capacitance sensor Pending JP2013181884A (en)
JP2012046640A JP2013181884A (en) 2012-03-02 2012-03-02 Electrostatic capacitance sensor
EP13157351.1A EP2634587A3 (en) 2012-03-02 2013-03-01 Electrostatic capacitance sensor
US13/782,777 US9274153B2 (en) 2012-03-02 2013-03-01 Electrostatic capacitance sensor
JP2013181884A true JP2013181884A (en) 2013-09-12
ID=47826952
JP2012046640A Pending JP2013181884A (en) 2012-03-02 2012-03-02 Electrostatic capacitance sensor
US (1) US9274153B2 (en)
EP (1) EP2634587A3 (en)
JP (1) JP2013181884A (en)
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2012-03-02 JP JP2012046640A patent/JP2013181884A/en active Pending
2013-03-01 US US13/782,777 patent/US9274153B2/en active Active
2013-03-01 EP EP13157351.1A patent/EP2634587A3/en not_active Withdrawn
US20130229193A1 (en) 2013-09-05
US9274153B2 (en) 2016-03-01
EP2634587A3 (en) 2013-10-16
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