JP2010223640A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve both the ensuring of the rigidity of a cap and a reduction in the planar size of a through electrode provided in the cap. <P>SOLUTION: A groove 30 is provided on part of bottoms 21c, 21d of recesses 21a, 21b, respectively, and a wiring section 24 is provided in the groove 30. The through electrode 25, which is in contact with the wiring section 24 and is electrically connected thereto, is provided inside a through-hole 32, which is smaller than a bottom 31 of the groove 30. By providing the groove 30 in the cap 20, a part at which the through-hole 32 is formed in the cap 20 becomes small in thickness, thereby the planar size of the through-hole 32 is reduced. By reducing the thickness of only the part at which the through-hole 32 is formed in the cap 20 by the groove 30, the thickness of the part at which the through-hole 32 is not formed in the cap 20 can be maintained, thereby ensuring the rigidity of the cap 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor device including a sensor unit provided with a sensing unit and a cap unit, the sensing unit being hermetically sealed between the sensor unit and the cap unit, and a manufacturing method thereof.

  Conventionally, for example, Patent Document 1 proposes a semiconductor device including a sensor unit including a sensing unit and a cap unit that contacts the sensor unit. This semiconductor device has a structure in which a cavity (sealing space) is formed between the sensor unit and the cap unit by the cap unit facing and abutting the sensor unit, and the sensing unit is sealed in the cavity. I am doing.

  Moreover, the cap part is provided with the penetration electrode extended in the lamination direction of the sensor part and the cap part. The through electrode is electrically connected to the sensing unit. For this reason, the potential of the sensing part can be taken out to the cap part side through the through electrode.

JP 2008-20433 A

  However, in the above conventional technique, when the cap portion is thick, a through hole having a large size must be formed, and the through electrode must be embedded inside the through hole. For this reason, there is a problem that the size of the through hole is increased and the planar size of the semiconductor device is increased.

  Therefore, it can be considered that the cap portion is made thin and then attached to the sensor portion. However, since the rigidity of the cap portion is reduced because the cap portion is thin, there is a problem that handling of the cap portion is reduced.

  On the other hand, it is also conceivable that the cap portion is thinned after the cap portion is attached to the sensor portion, and a through hole is formed in the thinned cap portion. However, since the cap portion is provided with a recess for forming a cavity, the stress when thinning the cap portion is applied to the connection portion between the bottom surface and the side surface constituting the recess, and the cap portion is cracked. Problems arise.

  As described above, there is a problem that ensuring the rigidity of the cap portion and reducing the planar size of the through electrode are not compatible.

  In view of the above points, the present invention provides a semiconductor device having a structure capable of satisfying both of securing rigidity of a cap portion and reducing a planar size of a through electrode provided in the cap portion, and a method for manufacturing the same. With the goal.

  In order to achieve the above object, according to the first aspect of the present invention, the cap portion (20) includes a groove portion in which a part of the bottom (21c, 21d) of the recess (21a, 21b) is recessed toward the other surface (20b). (30), a wiring part (24) disposed in the groove part (30) and the concave part (21a, 21b) and electrically connected to the sensing part (14, 15), and a bottom part (21c, 21d) While penetrating the other surface (20b), the through hole (32) having a size smaller than the bottom surface (31) of the groove (30), the inside of the through hole (32), and the other surface (20b) And a through electrode (25) electrically connected to the wiring portion (24) exposed from the bottom surface (31).

  In the invention according to claim 2, the cap part (20) is a groove part in which a part of the other surface (20b) including the region where the recesses (21a, 21b) are projected is recessed toward the one surface (20a). (30), the groove portion (30) and the wiring portion (24) disposed on the other surface (20b), the bottom surface (31) and the bottom portions (21c, 21d), and the bottom surface of the groove portion (30) ( 31) and a through hole (32) having a size smaller than that of 31), disposed in the through hole (32) and the recesses (21a, 21b), and electrically connected to the wiring portion (24) exposed from the bottom surface (31). And a through electrode (25) electrically connected to the sensing part (14, 15).

  According to invention of Claim 1 and Claim 2, since the thickness of the part in which a through-hole (32) is formed among cap parts (20) becomes small by a groove part (30), a through-hole (32) The plane size can be reduced. On the other hand, the portion of the cap portion (20) where the through hole (32) is formed is thin, but the thickness of the portion where the through hole (32) is not formed does not change, so the rigidity of the cap portion (20) is reduced. It can be secured. Therefore, it is possible to achieve both of ensuring the rigidity of the cap part (20) and reducing the planar size of the through electrode (25) provided in the cap part (20).

  The invention according to claim 3 is characterized in that the groove (30) is formed such that the diameter of the groove (30) decreases from the one surface (20a) side to the other surface (20b) side.

  According to this, since the wall surface of the groove part (30) is inclined, a structure in which the wiring part (24) can be easily formed on the wall surface of the groove part (30) can be obtained.

  The invention according to claim 4 is characterized in that the through electrode (25) is formed on the wall surface of the through hole (32) so that a space is left in the through hole (32).

  According to this, since the amount of the through electrode (25) disposed inside the through hole (32) is reduced, the thermal stress generated in the through electrode (25) is reduced. Thereby, the influence which this thermal stress has on a sensing part (14, 15) can be reduced.

  The invention according to claim 5 is characterized in that the wiring part (24) is formed on the wall surface of the groove part (30) so that a space part is left in the groove part (30).

  According to this, since the amount of the wiring part (24) disposed inside the groove part (30) is reduced, the thermal stress generated in the wiring part (24) is reduced. Therefore, stress relaxation of the wiring part (24) can be achieved.

  In the invention according to claim 6, the joining member (40) arranged so as to make a round of the outer edge part of the surface (10a) is provided between the sensor part (10) and the cap part (20). It is characterized by that.

  According to this, since the sensing parts (14, 15) of the sensor part (10) are separated from the cap part (20) by the height of the joining member (40), the sensing parts (14, 15) are separated from the cap part (20). ). Therefore, failure of the sensing unit (14, 15) can be avoided.

  In the invention according to claim 7, in the step of preparing the cap portion (20), a groove portion (30) in which a part of the bottom portion (21c, 21d) of the recess portion (21a, 21b) is recessed toward the other surface (20b) side. Forming a wiring portion (24) that is disposed in the groove portion (30) and the concave portion (21a, 21b) and electrically connected to the sensing portion (14, 15), and a bottom surface ( 31) and the other surface (20b) and a step of forming a through hole (32) having a size smaller than the bottom surface (31) of the groove (30), the inside of the through hole (32) and the other surface ( 20b) and forming a through electrode (25) electrically connected to the wiring portion (24) exposed from the bottom surface (31).

  In the invention according to claim 8, in the step of preparing the cap portion (20), a part of the other surface (20b) including the region where the recesses (21a, 21b) are projected is on the one surface (20a) side. A step of forming a recessed groove portion (30), a step of forming a wiring portion (24) on the groove portion (30) and the other surface (20b), and a bottom surface (31) and a bottom portion (21c, 21d). In addition, the step of forming a through hole (32) having a size smaller than the bottom surface (31) of the groove (30) and the through hole (32) and the recesses (21a, 21b) are disposed and exposed from the bottom surface (31). And a step of forming a through electrode (25) so as to be electrically connected to the wiring part (24) and to be electrically connected to the sensing part (14, 15).

  According to invention of Claim 7 and Claim 8, by forming the groove part (30) in the cap part (20), the thickness of the part which forms a through-hole (32) among cap parts (20) is made small. Therefore, the planar size of the through hole (32) can be reduced. On the other hand, the portion of the cap portion (20) where the through hole (32) is formed is thin, but the thickness of the portion where the through hole (32) is not formed does not change, so the rigidity of the cap portion (20) can be ensured. Therefore, it is possible to achieve both of ensuring the rigidity of the cap part (20) and reducing the planar size of the through electrode (25) provided in the cap part (20).

  In the invention according to claim 9, in the step of forming the groove (30), the groove (30) is formed so that the diameter of the groove (30) decreases from the one surface (20a) side to the other surface (20b) side. It is characterized by doing.

  According to this, since the wall surface of the groove part (30) is inclined, the wiring part (24) can be easily formed on the wall surface of the groove part (30).

  In the invention described in claim 10, in the step of forming the through electrode (25), the through electrode (25) is formed on the wall surface of the through hole (32) so that a space is left in the through hole (32). It is characterized by that.

  According to this, since the amount of material used for forming the through electrode (25) is reduced, a structure in which thermal stress generated in the through electrode (25) is reduced can be obtained. Thereby, the structure which can reduce the influence which this thermal stress has on a sensing part (14, 15) can be obtained.

  In the invention according to claim 11, in the step of forming the wiring portion (24), the wiring portion (24) is formed on the wall surface of the groove portion (30) so that a space portion is left in the groove portion (30). Features.

  According to this, since the amount of the wiring part (24) formed inside the groove part (30) is reduced, a structure in which the thermal stress generated in the wiring part (24) is reduced can be formed. Therefore, stress relaxation of the wiring part (24) can be achieved.

  In the invention according to claim 12, in the step of hermetically sealing the sensing portions (14, 15) in the cavities (16-18), the surface (10a) is interposed between the sensor portion (10) and the cap portion (20). ), The joining member (40) is arranged so as to go around the outer edge portion.

  According to this, since the sensing part (14, 15) of the sensor part (10) can be separated from the cap part (20) by the height of the joining member (40), the sensing part (14, 15) is the cap part. A structure that is difficult to hit (20) can be formed.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a plan view of a semiconductor device according to a first embodiment of the present invention. It is AA sectional drawing of FIG. It is a partial expanded sectional view of a semiconductor device. It is the figure which showed the manufacturing process of the semiconductor device. It is the figure which showed the manufacturing process following FIG. It is a partial expanded sectional view of the semiconductor device which concerns on 2nd Embodiment of this invention. It is a partial expanded sectional view of the semiconductor device which concerns on 3rd Embodiment of this invention. It is sectional drawing of the semiconductor device which concerns on 4th Embodiment of this invention. (A) is a top view of the semiconductor device which concerns on 5th Embodiment of this invention, (b) is BB sectional drawing of (a). It is sectional drawing of the semiconductor device which concerns on 6th Embodiment of this invention. It is a partially expanded sectional view of the semiconductor device which concerns on 7th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The semiconductor device described below includes a mechanical quantity sensor such as an acceleration sensor having a movable part and an angular velocity sensor (gyro sensor), and is used for detecting, for example, vehicle acceleration and angular velocity.

  FIG. 1 is a plan view of the semiconductor device according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a partially enlarged cross-sectional view of the semiconductor device. Hereinafter, a description will be given with reference to FIGS.

  As shown in FIG. 2, the semiconductor device is configured such that a plate-like cap unit 20 is bonded to a surface 10 a of a plate-like sensor unit 10.

First, the structure of the sensor unit 10 will be described. The sensor unit 10 has a structure in which a sacrificial layer 13 is sandwiched between a support substrate 11 and a semiconductor layer 12, and is configured as a so-called SOI substrate. Among these, the surface of the semiconductor layer 12 opposite to the sacrificial layer 13 corresponds to the surface 10 a of the sensor unit 10. The material of the support substrate 11 is, for example, single crystal silicon, and the material of the semiconductor layer 12 is, for example, polysilicon. Material of the sacrificial layer 13 is, for example, SiO _2.

  In the semiconductor layer 12, for example, a first sensing unit 14 and a second sensing unit 15 for detecting acceleration are formed. The first sensing unit 14 is configured to detect acceleration applied in the thickness direction perpendicular to the planar direction of the semiconductor layer 12, that is, acceleration in the Z-axis direction. The second sensing unit 15 is configured to detect acceleration applied in the planar direction of the semiconductor layer 12, that is, acceleration in the X-axis direction.

  The first sensing unit 14 is configured by forming an anchor unit, a beam unit, and a vibrator in the semiconductor layer 12. Specifically, the anchor portion and the vibrator are connected by a beam portion having a spring property, and the vibrator is supported in a floating state with respect to the support substrate 11. The vibrator is configured to vibrate in the Z-axis direction according to the acceleration received by the semiconductor device from the outside.

  The second sensing unit 15 is configured by forming a movable part and a fixed part in the semiconductor layer 12. Among these, the movable part includes an anchor part, a weight part, a movable electrode, and a beam part. Specifically, the anchor portion and the elongated weight portion are connected by a beam portion having a spring property, and the weight portion is supported in a state of floating with respect to the support substrate 11. Thereby, the weight part can move in the longitudinal direction of the weight part. Further, a plurality of movable electrodes are provided in a comb shape in a direction perpendicular to the longitudinal direction of the weight portion.

  The fixed part includes a fixed wiring part and a fixed electrode. The fixed wiring portion is disposed at a position facing the weight portion. The fixed electrodes extend in a direction perpendicular to the side of the fixed wiring portion that faces the weight portion, and are arranged in a comb shape by being provided with a plurality of fixed wiring portions.

  Each fixed electrode is disposed opposite to each movable electrode, and a capacitor is formed between each fixed electrode and each movable electrode. As a result, when the weight portion receives the acceleration and moves in the X-axis direction, the capacitance value of the capacitor changes. Therefore, the acceleration can be detected based on the change in the capacitance value.

  Next, the cap part 20 will be described. The cap unit 20 prevents water and foreign matter from entering the sensing units 14 and 15, and includes one surface 20a facing the surface 10a of the sensor unit 10 and another surface 20b opposite to the one surface 20a. have. In addition, the cap unit 20 also serves to form a sealed space with the sensor unit 10.

  As shown in FIGS. 1 and 2, the cap portion 20 includes a bonded substrate 21, a first insulating film 22, a second insulating film 23, a wiring portion 24, a through electrode 25, and first to fifth wirings. 26a to 26e, first to fifth pads 27a to 27e, and a bonding function wiring 28.

  The bonded substrate 21 has a first recess 21a and a second recess 21b in which a part of the surface of the bonded substrate 21 that faces the sensor unit 10 is recessed toward the other surface 20b. The first recess 21 a is formed at a position facing the first sensing unit 14 of the sensor unit 10 in the bonded substrate 21, and the second recess 21 b is formed at a position facing the second sensing unit 15. As such a bonded substrate 21, a silicon substrate, a glass substrate, or the like is used.

  Further, as shown in FIG. 3, a groove portion 30 in which a part of the bottom portions 21c and 21d is recessed toward the other surface 20b is formed in each bottom portion 21c and 21d of each concave portion 21a and 21b. The size of the groove portion 30 is sufficiently smaller than the size of the concave portions 21a and 21b. In the present embodiment, a total of four groove portions 30 are formed in each of the recesses 21a and 21b. In FIG. 2, two of the four grooves 30 are shown. Further, FIG. 3 shows a groove 30 formed at the outermost edge of the bottom 21c of the first recess 21a.

  As shown in FIG. 2, the first insulating film 22 is an insulating film formed on the entire surface of the bonded substrate 21. Therefore, the first insulating film 22 is also formed on the recesses 21 a and 21 b and the side surface of the bonded substrate 21. A surface of the first insulating film 22 that faces the sensor unit 10 corresponds to one surface 20 a of the cap unit 20.

  The second insulating film 23 is formed on the first insulating film 22 formed on the surface of the bonded substrate 21 opposite to the surface on which the concave portions 21a and 21b are formed. The surface of the second insulating film 23 corresponds to the other surface 20 b of the cap portion 20.

An insulating material such as SiO ₂ is used as the material of the first insulating film 22, and an insulating material such as TEOS is used as the material of the second insulating film 23.

  And as FIG. 3 shows, the wiring part 24 is formed on the 1st insulating film 22 formed in the groove part 30 and the 1st recessed part 21a. As described above, since the cap portion 20 is provided with the four groove portions 30, the wiring portions 24 are formed in the respective groove portions 30.

  The wiring unit 24 is a wiring used for the sensing units 14 and 15. In the present embodiment, the one connected to the anchor part of the first sensing unit 14, the one serving as a fixed electrode for the vibrator of the first sensing unit 14, the one connected to the anchor part of the second sensing unit 15, 2 Some are connected to the fixed wiring portion of the sensing unit 15.

  Specifically, as shown in FIG. 2, the wiring part 24 serving as a fixed electrode for the vibrator of the first sensing part 14 is positioned at the position facing the vibrator in the bottom part 21 c of the first recess 21 a, and the groove part 30. The wall surface, the wall surface of the first recess 21a, and the one surface 20a of the cap portion 20 are patterned. As a result, a capacitor is formed between the wiring portion 24 and the vibrator, and when the vibrator is subjected to acceleration and moves in the Z-axis direction, the capacitance of the capacitor is changed based on a change in the distance between the vibrator and the wiring portion 24. Since the capacitance value changes, it is possible to detect acceleration. Since the wiring portion 24 only needs to be disposed at a position facing the vibrator, the wiring portion 24 may not be patterned so as to be disposed on the one surface 20a of the cap portion 20.

  The wiring part 24 connected to the anchor part of the second sensing part 15 is patterned along the wall surface of the groove part 30, the wall surface of the first recess 21a, and the one surface 20a of the cap part 20, as shown in FIG. Yes. Thereby, the wiring part 24 and the anchor part are electrically connected.

  Further, for the wiring part 24 connected to the anchor part of the first sensing part 14 and the wiring part 24 connected to the fixed wiring part of the second sensing part 15, the wall surface of the groove part 30, the first recess 21a, and the cap Patterned along one surface 20 a of the portion 20.

  The wiring part 24 is formed on the wall surface of the groove part 30 so that a space part is left in the groove part 30. That is, the wiring part 24 in the groove part 30 is hollow and is not completely buried in the groove part 30. As a result, the amount of the wiring part 24 disposed inside the groove part 30 is reduced, so that the thermal stress generated in the wiring part 24 is reduced. Therefore, stress relaxation of the wiring part 24 is achieved.

  As shown in FIG. 3, the cap portion 20 is formed with a through hole 32 that penetrates the bottom surface 31 and the other surface 20 b of the groove portion 30. The through hole 32 is smaller than the bottom surface 31 of the groove 30. A second insulating film 23 is formed on the wall surface of the through hole 32, and a part of the first insulating film 22 is removed so that the wiring part 24 is exposed inside the through hole 32. A through electrode 25 is formed inside the through hole 32 and on the other surface 20b. The through electrode 25 is embedded in the through hole 32. One of the through electrodes 25 is in contact with the wiring part 24 and is electrically connected to the wiring part 24, and the other is patterned on the other surface 20 b of the cap part 20.

  Specifically, as shown in FIG. 1, each through electrode 25 is patterned on the other surface 20 b of the cap portion 20 so as to be connected to each pad 27 a to 27 e via each wiring 26 a to 26 e. .

  The through electrode 25 connected to the wiring portion 24 serving as a fixed electrode of the vibrator is connected to the first pad 27a via the first wiring 26a. The through electrode 25 that contacts the wiring part 24 joined to the anchor part of the first sensing part 14 is connected to the second pad 27b via the second wiring 26b. The through electrode 25 that contacts the wiring part 24 joined to the anchor part of the second sensing part 15 is connected to the third pad 27c via the third wiring 26c. The through electrode 25 that contacts the wiring portion 24 joined to the fixed wiring portion of the second sensing portion 15 is connected to the fourth pad 27d via the fourth wiring 26d.

  Further, the cap portion 20 is provided with a through hole 32 that penetrates the second insulating film 23 and the first insulating film 22 to reach the bonded substrate 21, and takes the potential of the bonded substrate 21 in the through hole 32. The through electrode 25 is embedded. As shown in FIG. 1, the through electrode 25 is connected to the fifth pad 27 e via the fifth wiring 26 e on the other surface 20 b of the cap portion 20.

  In the above configuration, the thickness from the one surface 20a to the other surface 20b of the cap portion 20 is, for example, 400 μm. Moreover, the thickness from the one surface 20a of the cap part 20 to the bottom face 31 of the groove part 30 is 300 micrometers, for example. That is, the thickness from the bottom surface 31 of the groove part 30 to the other surface 20b of the cap part 20 is 100 μm. The planar size of the through hole 32 is, for example, 50 μm. The size of the bottom surface 31 of the groove part 30 is larger than 50 μm.

  The bonding functional wiring 28 is for bonding the sensor unit 10 and the cap unit 20 as shown in FIGS. 1 and 2. The bonding functional wiring 28 is patterned on the outer edge portion of the surface 10a of the sensor unit 10 so as to go around the outer edge portion. The thickness of the bonding functional wiring 28 is the same as the thickness of each wiring portion 24 patterned on the one surface 20a of the cap portion 20.

  For example, Al is used as the material of the wiring part 24, the through electrode 25, the first to fifth wirings 26a to 26e, and the first to fifth pads 27a to 27e. Of course, not only Al but also wiring materials such as Al—Si, Al—Si—Cu, PolySi, and Al—Ge may be used.

  In addition, the sensor unit 10 and the cap unit 20 are stacked via the bonding function wiring 28, thereby forming the first cavity 16 between the first recess 21 a and the sensor unit 10. The first sensing part 14 is hermetically sealed in the first cavity 16. Similarly, the second cavity 17 is formed between the second recess 21 b and the sensor unit 10. The second sensing unit 15 is hermetically sealed in the second cavity 17. The cavities 16 and 17 are set to a vacuum or a predetermined atmospheric pressure, for example. The above is the overall configuration of the semiconductor device according to the present embodiment.

  Next, a method for manufacturing the semiconductor device will be described with reference to FIGS. 4 and 5 are views corresponding to the AA cross section of FIG.

  The sensor unit 10 is manufactured as follows. First, an SOI substrate in which the sacrificial layer 13 is sandwiched between the support substrate 11 and the semiconductor layer 12 is prepared. Then, a mask is formed on the semiconductor layer 12, and the mask is patterned corresponding to the structures of the sensing units 14 and 15 in the mask. Thereafter, the semiconductor layer 12 exposed from the mask is etched by, for example, the RIE method, and the mask is removed.

  Subsequently, the sacrificial layer 13 exposed from the semiconductor layer 12 is removed by sacrificial layer etching or the like. Thereby, the vibrator and the like of the first sensing part 14 and the weight part and the like of the second sensing part 15 are released from the support substrate 11 to form the sensing parts 14 and 15. Thus, the sensor unit 10 is completed.

  The cap part 20 is manufactured as follows. First, in the step shown in FIG. 4A, a bonded substrate 21 is prepared, and a resist mask 40 for forming a cavity is formed on the surface facing the sensor unit 10. And the 1st recessed part 21a and the 2nd recessed part 21b are formed in the bonding board | substrate 21 by dry etching or wet etching.

  In the step shown in FIG. 4B, the resist mask 40 is applied to the bottom portions 21c and 21d of the recesses 21a and 21b so that the locations where the groove portions 30 are formed in the bottom portions 21c and 21d of the recesses 21a and 21b are exposed. Form. Then, the bonded substrate 21 is dry etched by, for example, the RIE method. Thereby, the groove part 30 of the size deeper than each recessed part 21a, 21b and smaller than each recessed part 21a, 21b is formed in each recessed part 21a, 21b. Thereafter, the resist mask 40 is removed.

  Here, since the groove part 30 is only formed in a part of each bottom part 21c, 21d of each recessed part 21a, 21b, and does not penetrate the bonded substrate board 21, the rigidity of the bonded substrate board 21 as a whole is maintained. The Therefore, the handling of the bonded substrate 21 is not reduced by forming the groove 30.

  In the step shown in FIG. 4C, the first insulating film 22 is formed on the entire surface of the bonded substrate 21 by subjecting the bonded substrate 21 to heat treatment. Further, a metal film 41 made of Al or the like is formed on the entire region of the first insulating film 22 that becomes the one surface 20a of the cap portion 20.

  In the step shown in FIG. 4D, the metal film 41 is patterned. Thereby, the wiring part 24 and the bonding functional wiring 28 are formed on the one surface 20a of the cap part 20, respectively. In this step, the wiring part 24 is formed on the wall surface of the groove part 30 so that a space part is left in the groove part 30. This is because the amount of the wiring part 24 disposed in the groove part 30 is reduced and stress relaxation of the wiring part 24 is achieved.

  In the step shown in FIG. 4 (e), the first insulation is performed at a position corresponding to each groove 30 on the surface of the bonded substrate 21 opposite to the surface on which the recesses 21a and 21b are formed by, for example, the RIE method. Through holes 32 penetrating the film 22 and the bonded substrate 21 are formed. In this case, the through hole 32 having a size smaller than the bottom surface 31 of the groove 30 is formed. As a result, the first insulating film 22 formed on the wall surface of the groove 30 is exposed in each through hole 32.

  In this case, the depth of the through hole 32 when forming the through hole 32 is from the surface of the first insulating film 22 to the bottom surface 31 of the groove 30, and the concave portions 21 a and 21 b are formed from the surface of the first insulating film 22. It is shorter than the depth to the bottom 21c, 21d. That is, a groove 30 is formed in a part of the bottoms 21c and 21d of the recesses 21a and 21b of the bonded substrate 21, and a through-hole 32 is formed at a location where the bonded substrate 21 is locally thinned by the groove 30. Therefore, the depth of the through hole 32 is reduced. In other words, by using the recesses of the recesses 21a and 21b and the recesses of the groove portions 30 formed in the bottoms 21c and 21d of the recesses 21a and 21b, the portion of the cap portion 20 that forms the through hole 32. Can be reduced in thickness. Thus, since the depth of the through hole 32 can be reduced, the planar size of the through hole 32 can be reduced.

  Moreover, although the site | part in which the groove part 30 was formed among the bonded substrates 21 is thin locally, this part is only a part of bonded substrate 21, ie, each recessed part 21a, 21b. That is, the portion of the bonded substrate 21 where the through hole 32 is formed is thin, but the thickness of the portion where the through hole 32 is not formed does not change. That is, since the thickness of the entire bonded substrate 21 has not changed, the rigidity of the bonded substrate 21 is maintained.

  Then, a second insulating film 23 such as TEOS is formed on the wall surface of the through hole 32 and the first insulating film 22 on the surface side where the through hole 32 is provided by using a plasma CVD method, a PVD method, or the like.

  In the step shown in FIG. 5A, the second insulating film 23 and the first insulating film 22 in the through hole 32 are removed by dry etching or the like so as to be in electrical contact with the wiring portion 24 in the groove 30. . Thereby, the wiring part 24 is exposed in the through hole 32. Further, in order to take out the potential of the bonded substrate 21, a through hole 32 is formed so as to penetrate the first insulating film 22 and the second insulating film 23 and expose the bonded substrate 21.

  In the step shown in FIG. 5B, a metal film such as Al is formed on the second insulating film 23, and the metal film is patterned as shown in FIG. 25, and the first to fifth wirings 26a to 26e and the first to fifth pads 27a to 27e are formed on the second insulating film 23. In this way, the cap part 20 is completed.

  In the step shown in FIG. 5C, for example, the sensor unit 10 and the cap unit 20 are integrated in a vacuum. In this case, the surface of each wiring part 24 and the surface of the bonding function wiring 28 are interface-activated and bonded to the surface 10 a of the sensor part 10. The joining method is not limited to this, and other methods may be used.

  Accordingly, the first sensing unit 14 is hermetically sealed in the first cavity 16, and the second sensing unit 15 is hermetically sealed in the second cavity 17. Thus, the semiconductor device is completed.

  Although a method for manufacturing one semiconductor device has been described above, actually, a wafer-like SOI substrate is prepared, a large number of sensor portions 10 are formed on the SOI substrate, and a wafer-like bonded substrate 21 is prepared. Thus, a large number of cap portions 20 can be formed on the bonded substrate 21. In this case, a semiconductor device can be obtained by pasting them together and then dicing cut and dividing them individually.

  As described above, in this embodiment, the groove part 30 is provided in a part of each bottom part 21c, 21d of each recessed part 21a, 21b, and the wiring part 24 is provided in this groove part 30. In addition, a feature is that a through electrode 25 that is in contact with and electrically connected to the wiring portion 24 is provided in a through hole 32 having a size smaller than the bottom surface 31 of the groove portion 30.

  According to this, since the groove part 30 is provided in the cap part 20, the thickness of the site | part in which the through-hole 32 is formed in the cap part 20 becomes small. Accordingly, since the through hole 32 is formed in a portion of the cap portion 20 that is thinned by forming the groove portion 30, the planar size of the through hole 32 can be reduced.

  Moreover, since only the site | part in which the through-hole 32 is formed among the cap parts 20 is made thin by the groove part 30, the thickness of the other part in which the through-hole 32 is not formed among the cap parts 20 is maintainable. Therefore, the rigidity of the cap part 20 can be ensured.

  Thus, by providing the groove portion 30, it is possible to achieve both securing the rigidity of the cap portion 20 and reducing the planar size of the through electrode 25 provided in the cap portion 20.

(Second Embodiment)
In the present embodiment, only different parts from the first embodiment will be described. FIG. 6 is a partially enlarged cross-sectional view of the semiconductor device according to the present embodiment. As shown in this figure, in the present embodiment, the wall surface of the groove 30 is inclined.

  Specifically, the groove portion 30 is formed so that the diameter of the groove portion 30 decreases from the one surface 20a side of the cap portion 20 to the other surface 20b side. The groove 30 having such a structure can be formed by isotropically etching the bonded substrate 21 in the step shown in FIG. By inclining the wall surface of the groove part 30 in this way, the wiring part 24 can be easily formed on the wall surface of the groove part 30.

(Third embodiment)
In the present embodiment, only parts different from the first and second embodiments will be described. FIG. 7 is a partially enlarged cross-sectional view of the semiconductor device according to the present embodiment. As shown in this figure, the through electrode 25 is formed on the wall surface of the through hole 32 so that a space is left in the through hole 32. That is, “the wall surface of the through hole 32” means that the through electrode 25 is not embedded in the through hole 32 but formed only on the wall surface of the through hole 32. That is, the through electrode 25 in the through hole 32 is hollow and is not completely buried in the through hole 32.

  Such a structure forms the metal film only on the wall surface of the through hole 32 when forming the metal film in the through hole 32 in the step shown in FIG.

  As described above, since the through electrode 25 is formed only on the wall surface of the through hole 32 in the through hole 32, the amount of the through electrode 25 disposed inside the through hole 32 can be reduced. . Moreover, since the amount of the metal material used as the through electrode 25 is reduced, the thermal stress generated in the through electrode 25 in the through hole 32 is reduced, and the stress can be relaxed. Thereby, the influence which this thermal stress has on each sensing part 14 and 15 can be reduced.

(Fourth embodiment)
In the present embodiment, only parts different from the first to third embodiments will be described. FIG. 8 is a cross-sectional view of the semiconductor device according to the present embodiment, and corresponds to a cross section taken along the line AA of FIG. As shown in this figure, a joining member 40 is provided between the sensor unit 10 and the cap unit 20.

  The bonding member 40 is provided between the bonding function wiring 28 and the surface 10a of the sensor unit 10 so as to make a round of the outer edge portion of the surface 10a of the sensor unit 10, and the wiring unit 24 and the surface 10a of the sensor unit 10. Between the first sensing unit 14 and the first sensing unit 14. As a result, the first sensing unit 14 is hermetically sealed to the first cavity 16 by the joining member 40 surrounding the first sensing unit 14, and the second sensing unit 15 is sealed by the sealing member surrounding the second sensing unit 15. The two cavities 17 are hermetically sealed.

  As the bonding member 40, for example, a metal material such as a eutectic alloy is used, and the sensor unit 10 and the cap unit 20 are bonded by eutectic bonding, bump bonding, or the like.

  Such a structure is obtained by disposing the joining member 40 between the sensor unit 10 and the cap unit 20 and joining them together in the step shown in FIG.

  As described above, by providing the bonding member 40 between the sensor unit 10 and the cap unit 20, the sensing units 14 and 15 of the sensor unit 10 are separated from the cap unit 20 by the height of the bonding member 40. . For this reason, since each sensing part 14 and 15 becomes difficult to hit cap part 20, failure of each sensing part 14 and 15 can be avoided.

(Fifth embodiment)
In the present embodiment, only portions different from the first to fourth embodiments will be described. In each of the embodiments described above, the cavities 16 and 17 in which the sensing units 14 and 15 are arranged are configured as separated spaces. However, in the present embodiment, the sensing units 14 and 15 are arranged in one space. It has a structure.

  FIG. 9A is a plan view of the semiconductor device according to the present embodiment, and FIG. 9B is a cross-sectional view taken along the line BB in FIG. 9A.

  As shown in FIG. 9B, the bonded substrate 21 is provided with a first recess 21a and a second recess 21b slightly deeper than the first recess 21a at the bottom 21c of the first recess 21a. Yes. Also, a plurality of groove portions 30 are provided in a part of the bottom portions 21c and 21d of the recess portions 21a and 21b, and the bottom surface 31 of the groove portion 30 and the surface of the bonded substrate 21 opposite to the sensor portion 10 penetrate. Each through hole 32 is provided. A first insulating film 22 is formed on the entire surface of the bonded substrate 21.

  The wiring part 24 is formed in the groove part 30 as described above, and is patterned as described above. Each wiring portion 24 is in contact with and electrically connected to each through electrode 25 embedded in each through hole 32.

  In the present embodiment, seven groove portions 30 are provided in the bottom portions 21c and 21d of the concave portions 21a and 21b. As shown in FIG. 9A, seven through holes 32 corresponding to the groove portions 30 are provided. And the penetration electrode 25 is provided.

  The first pad 27a is connected to the wiring portion 24 serving as a fixed electrode of the vibrator via the first wiring 26a and the through electrode 25. The second pad 27 b is connected to the anchor portion of the first sensing unit 14 through the second wiring 26 b and the through electrode 25. Further, the four third pads 27 c are connected to each part of the second sensing unit 15. The fifth pad 27 e is connected to the bonded substrate 21 via the fifth wiring 26 e and the through electrode 25.

  In the present embodiment, the surface of the first insulating film 22 formed on the surface of the cap unit 20 that faces the sensor unit 10 corresponds to the one surface 20a of the cap unit 20, and is the surface opposite to the one surface 20a. Corresponds to the other surface 20 b of the cap portion 20.

  Then, when the sensor unit 10 is bonded to the cap unit 20 via the bonding function wiring 28, one third cavity 18 is formed between each of the recesses 21a and 21b and the sensor unit 10, and this third cavity 18, the sensing units 14 and 15 are hermetically sealed.

  As described above, even when the sensing portions 14 and 15 are hermetically sealed in the third cavity 18 that is one space, the other surface 20b of the cap portion 20 is interposed via the wiring portion 24 and the through electrode 25. A potential can be taken out.

(Sixth embodiment)
In the present embodiment, only parts different from the first to fifth embodiments will be described. In each of the above embodiments, the first sensing unit 14 and the second sensing unit 15 are configured to detect acceleration, respectively, but in the present embodiment, the first sensing unit 14 detects acceleration in the Z-axis direction, The second sensing unit 15 is configured to detect pressure.

  FIG. 10 is a cross-sectional view of the semiconductor device according to the present embodiment. As shown in this figure, the second sensing unit 15 is configured to detect absolute pressure. Specifically, the support substrate 11 and the sacrificial layer 13 are etched or the like so that the semiconductor layer 12 is exposed from the support substrate 11 to form a recess 19a. Thereby, a part of the semiconductor layer 12 is configured as a thin diaphragm 19b.

  Further, a gauge resistor 19c by ion implantation or the like is formed in the diaphragm 19b. The gauge resistor 19c is formed to constitute a bridge circuit. Accordingly, the pressure applied to the diaphragm 19b is detected using the piezoresistance effect, and an electric signal corresponding to the pressure is output. And when the 2nd cavity 17 is a vacuum, for example, the 2nd sensing part 15 detects the differential pressure, ie, absolute pressure, between the one surface and the other surface of the diaphragm 19b.

  As described above, when the plurality of sensing units 14 and 15 are formed in the sensor unit 10, different physical quantities such as acceleration and pressure can be detected. In this case, the first sensing unit 14 can be configured to detect acceleration in the X-axis direction as well as in the Z-axis direction. In addition, the differential pressure can be detected by setting the second cavity 17 to a predetermined atmospheric pressure.

(Seventh embodiment)
In the present embodiment, only parts different from the first to sixth embodiments will be described. In each of the above embodiments, the structure in which the groove portion 30 is formed on the sensor portion 10 side in the cap portion 20 has been described. However, the groove portion 30 may be formed on the cap portion 20 on the opposite side to the sensor portion 10. That is, this embodiment is characterized in that the through hole 32 is provided on the one surface 20a side of the cap portion 20 and the groove portion 30 is provided on the other surface 20b side.

  FIG. 11 is a partially enlarged cross-sectional view of the semiconductor device according to the present embodiment. As shown in this figure, the groove portion 30 is formed so that a part of the other surface 20b of the cap portion 20 including the region where the first recess 21a is projected is recessed toward the one surface 20a side of the cap portion 20. Yes. A second insulating film 23 is formed on the wall surface of the groove portion 30, and a wiring portion 24 is provided inside the groove portion 30 and on the other surface 20 b of the cap portion 20. The wiring part 24 is patterned into wirings and pads as shown in FIG. 1 and FIG.

  Further, the cap portion 20 has a through-hole 32 having a size smaller than that of the bottom surface 31 of the groove portion 30 while reaching the wiring portion 24 through the bottom surface 31 of the groove portion 30 and the bottom portion 21c of the first recess 21a. Yes. A first insulating film 22 is formed on the wall surface of the through hole 32, and the wiring part 24 is exposed in the through hole 32. In the through hole 32, a through electrode 25 used for the first sensing unit 14 is provided while being electrically connected to the wiring unit 24. In FIG. 11, the through electrode 25 is patterned so as to be disposed inside the through hole 32, the bottom 21 c of the first recess 21 a, and the one surface 20 a of the cap unit 20, and is a fixed electrode for the vibrator of the first sensing unit 14. The one used as is shown.

  As described above, even when the groove portion 30 is provided on the other surface 20b side of the cap portion 20, the groove portion 30 reduces the thickness of the portion of the cap portion 20 where the through hole 32 is formed. The plane size of 32 can be reduced. In addition, the entire bonded substrate 21 is not thinned in order to form the through hole 32, but the groove portion 30 is provided only in a part of the cap portion 20 where the through hole 32 is formed. The thickness of the cap portion 20 can be secured. Therefore, both the rigidity of the cap part 20 can be ensured and the planar size of the through electrode 25 provided in the cap part 20 can be reduced.

(Other embodiments)
In the above embodiments, the first sensing unit 14 is configured to detect acceleration in the Z-axis direction, and the second sensing unit 15 is configured to detect acceleration or pressure in the X-axis direction. This is just an example. Of course, the number of sensing units provided in the semiconductor device may be one or three or more. When there are three or more sensing units, for example, it can be a combination for detecting acceleration in three axial directions, or a combination of sensing units for detecting different physical quantities such as acceleration, angular velocity, and pressure.

  You may combine each structure shown by said each embodiment, respectively. For example, in the structure in which the groove portion 30 is provided on the other surface 20b side of the cap portion 20, the wall surface of the groove portion 30 can be inclined as shown in FIG.

  In each of the above embodiments, the structure in which the wiring part 24 is formed only on the wall surface of the groove part 30 so that the space part is left in the groove part 30 is shown, but the wiring part 24 is completely embedded in the groove part 30. May be.

DESCRIPTION OF SYMBOLS 10 Sensor part 10a Sensor part surface 14, 15 Sensing part 16, 17, 18 Cavity 20 Cap part 20a One surface of a cap part 20b Other surface of a cap part 21a, 21b Recessed part 21c, 21d Bottom part of a recessed part 24 Wiring part 25 Through electrode 30 Groove portion 31 Bottom surface of groove portion 32 Through hole 40 Joining member

Claims (12)

A sensor unit (10) having a surface (10a) and provided with sensing units (14, 15) on the surface (10a) side;
One surface (20a) facing the surface (10a), the other surface (20b) opposite to the one surface (20a), and a recess in which a part of the one surface (20a) is recessed toward the other surface (20b). A cap portion (20) having (21a, 21b),
The sensing unit (14, 15) is a semiconductor device hermetically sealed in a cavity (16-18) formed between the recess (21a, 21b) and the sensor unit (10),
The cap part (20)
A groove (30) in which a part of the bottom (21c, 21d) of the recess (21a, 21b) is recessed toward the other surface (20b);
A wiring part (24) disposed in the groove part (30) and the concave part (21a, 21b) and electrically connected to the sensing part (14, 15);
A through-hole (32) having a size smaller than the bottom surface (31) of the groove (30) while penetrating the bottom (21c, 21d) and the other surface (20b);
A through-electrode (25) disposed in the through-hole (32) and the other surface (20b) and electrically connected to the wiring portion (24) exposed from the bottom surface (31). A semiconductor device. A sensor unit (10) having a surface (10a) and provided with sensing units (14, 15) on the surface (10a) side;
One surface (20a) facing the surface (10a), the other surface (20b) opposite to the one surface (20a), and a recess in which a part of the one surface (20a) is recessed toward the other surface (20b). A cap portion (20) having (21a, 21b),
The sensing unit (14, 15) is a semiconductor device hermetically sealed in a cavity (16-18) formed between the recess (21a, 21b) and the sensor unit (10),
The cap part (20)
Of the other surface (20b), a part including a region where the recesses (21a, 21b) are projected is a groove (30) that is recessed toward the one surface (20a),
A wiring portion (24) disposed in the groove portion (30) and the other surface (20b);
A through-hole (32) having a size smaller than the bottom surface (31) of the groove (30) while penetrating the bottom surface (31) and the bottom (21c, 21d),
It is arrange | positioned at the said through-hole (32) and the said recessed part (21a, 21b), and while being electrically connected to the said wiring part (24) exposed from the said bottom face (31), it is connected to the said sensing part (14, 15). A semiconductor device comprising an electrically connected through electrode (25).   The said groove part (30) is formed so that the diameter of this groove part (30) may become small from the said one surface (20a) side to the said other surface (20b) side, The Claim 1 or 2 characterized by the above-mentioned. Semiconductor device.   The said through-electrode (25) is formed in the wall surface of the said through-hole (32) so that a space part may remain in the said through-hole (32), The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The semiconductor device described in one.   The wiring portion (24) is formed on a wall surface of the groove portion (30) so that a space portion is left in the groove portion (30). The semiconductor device described.   Between the said sensor part (10) and the said cap part (20), it has the joining member (40) arrange | positioned so that the outer edge part of the said surface (10a) may be made a round, It is characterized by the above-mentioned. Item 6. The semiconductor device according to any one of Items 1 to 5. Preparing a sensor unit (10) having a surface (10a) and having a sensing unit (14, 15) on the surface (10a) side;
One surface (20a) facing the surface (10a), the other surface (20b) opposite to the one surface (20a), and a recess in which a part of the one surface (20a) is recessed toward the other surface (20b). Preparing a cap portion (20) having (21a, 21b);
And a step of hermetically sealing the sensing part (14, 15) in a cavity (16-18) between the recess (21a, 21b) and the sensor part (10). And
In the step of preparing the cap part (20),
Forming a groove (30) in which a part of the bottom (21c, 21d) of the recess (21a, 21b) is recessed toward the other surface (20b);
Forming a wiring part (24) disposed in the groove part (30) and the recesses (21a, 21b) and electrically connected to the sensing part (14, 15);
A step of penetrating the bottom surface (31) and the other surface (20b) and forming a through hole (32) having a size smaller than the bottom surface (31) of the groove (30);
A through electrode (25) that is disposed in the through hole (32) and on the other surface (20b) and is electrically connected to the wiring portion (24) exposed from the bottom surface (31) is formed. A method for manufacturing a semiconductor device, comprising: a step. Preparing a sensor unit (10) having a surface (10a) and having a sensing unit (14, 15) on the surface (10a) side;
One surface (20a) facing the surface (10a), the other surface (20b) opposite to the one surface (20a), and a recess in which a part of the one surface (20a) is recessed toward the other surface (20b). Preparing a cap portion (20) having (21a, 21b);
And a step of hermetically sealing the sensing part (14, 15) in a cavity (16-18) between the recess (21a, 21b) and the sensor part (10). And
In the step of preparing the cap part (20),
Forming a groove (30) in which a part of the other surface (20b) including a region where the recesses (21a, 21b) are projected is recessed toward the one surface (20a);
Forming a wiring portion (24) in the groove portion (30) and the other surface (20b);
Forming a through hole (32) having a size smaller than the bottom surface (31) of the groove portion (30) while penetrating the bottom surface (31) and the bottom portion (21c, 21d);
It is arrange | positioned at the said through-hole (32) and the said recessed part (21a, 21b), and while being electrically connected to the said wiring part (24) exposed from the said bottom face (31), it is connected to the said sensing part (14, 15). Forming a through electrode (25) so as to be electrically connected to the semiconductor device.   In the step of forming the groove (30), the groove (30) is formed so that the diameter of the groove (30) decreases from the one surface (20a) side to the other surface (20b) side. A method for manufacturing a semiconductor device according to claim 7 or 8.   In the step of forming the through electrode (25), the through electrode (25) is formed on the wall surface of the through hole (32) so that a space is left in the through hole (32). A method for manufacturing a semiconductor device according to claim 7.   In the step of forming the wiring part (24), the wiring part (24) is formed on a wall surface of the groove part (30) so that a space part is left in the groove part (30). A method for manufacturing a semiconductor device according to any one of 7 to 10.   In the step of hermetically sealing the sensing part (14, 15) in the cavity (16-18), an outer edge part of the surface (10a) is provided between the sensor part (10) and the cap part (20). 12. The method of manufacturing a semiconductor device according to claim 7, wherein the joining member is arranged so as to make a round.

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