JP2013167468A - Pressure sensor and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor capable of preventing a pressure introduction hole from being filled with adhesive, and to provide a method for manufacturing the pressure sensor.SOLUTION: A pressure sensor 1 includes a diaphragm 2a sensitive to pressure, an adhesion part 3 opposed to the diaphragm 2a and a pressure introduction hole 3a penetrated into the adhesion part 3 and is configured so that a bottom of the adhesion part 3, which is located on the opposite side to the diaphragm 2a, is composed of a first surface 3c on which the pressure introduction hole 3a is arranged and a second surface 3d formed around the first surface 3c, the first surface 3c is projected from the second surface 3d, and an outer periphery 3f of the first surface 3c and an inner periphery 3g of the second surface 3d form a smoothly connected curve including no recessed portion in plan view.

Description

  The present invention relates to a technique for bonding a semiconductor chip to a substrate using an adhesive, and more particularly to a technique for bonding a pressure sensor having a pressure introducing hole to a substrate member.

  In the invention disclosed in Patent Document 1, as shown in FIG. 17, a sensor chip 303 in which a thin diaphragm 303 a is formed at the center is bonded to a thick film substrate 301 by a die bonding material 305. At this time, the sensor chip 303 is placed on and bonded to the convex member 301 c provided on the thick film substrate 301.

  FIG. 18 is a plan view when the rectangular inner peripheral surface 301d of the convex member 301c is provided 0.1 mm or more outside the inner end 303b of the sensor chip 303 in plan view. In this way, by providing the inner peripheral surface 301d outside the inner end portion 303b, the flange 303c is formed on the inner end portion 303b side of the sensor chip 303, and the die bonding material 305 is prevented from creeping up in the vicinity of the diaphragm 303a. doing.

  FIG. 19 shows a plan view in the case where the groove 301e is recessed in the convex member 301c so as to surround the inner peripheral surface 301d in addition to the flange 303c. As shown in FIG. 19, the outer peripheral surface and the inner peripheral surface of the groove 301e are formed in a rectangular shape in plan view. Thus, by providing the groove 301e, the die bonding material 305 is prevented from creeping up in the vicinity of the diaphragm 303a.

  In the invention disclosed in Patent Document 2, as shown in FIG. 20, the semiconductor chip 403 is bonded to the mounting substrate 401 using the adhesive 405 with the active surface 403a facing upward. At this time, the adhesive 405 protrudes from the lower surface 420 of the semiconductor chip 403 due to the load or heat treatment when the semiconductor chip 403 is mounted, scoops up the side surface 430 of the semiconductor chip 403, and the active surface 403 a is contaminated by the adhesive 405. there is a possibility.

  Therefore, when the plurality of semiconductor chips 403 are separated from the semiconductor wafer by dicing, the stepped portion 440 is formed on the side surface 430 of the semiconductor chip 403. The step portion 440 suppresses the adhesive 405 from scooping up the side surface 430 of the semiconductor chip 403.

JP-A-8-193897 JP 2011-129612 A

  In the prior art disclosed in Patent Document 1, the inner peripheral surface 301 d of the convex member 301 c is provided 0.1 mm or more outside the inner end portion 303 b of the sensor chip 303, and the flange 303 c is disposed on the inner end portion 303 b side of the sensor chip 303. As a result, the die bonding material 305 is prevented from creeping up in the vicinity of the diaphragm 303a.

  However, since the inner peripheral surface 301d is rectangular in plan view, the die bond material 305 is likely to gather at the corners of the four corners due to capillarity or the like generated in a narrow gap where each side wall constituting the inner peripheral surface 301d intersects. The die bond material 305 sometimes crawls up toward the diaphragm 303a starting from the corner.

  In addition, when the die bond material 305 flows into the groove 301e whose outer peripheral surface and inner peripheral surface are rectangular in plan view, capillary phenomenon or the like generated in the narrow gaps at the four corners where the side walls constituting the outer peripheral surface intersect, As the flow of the die bond material 305 stagnates at the four corners of the surface, the die bond material 305 that has flowed in easily gathers at the four corners of the groove 301e. Then, starting from the corner where the die bond material 305 gathers, the die bond material 305 may leak into the cavity 306 and crawl up to the diaphragm 303a side.

  As described above, since the inner peripheral surface 301d of the convex member 301c and the outer peripheral surface and inner peripheral surface of the groove 301e are formed in a rectangular shape in plan view, the problem that the die bonding material 305 creeps toward the diaphragm 303a side is solved. It was insufficient to do.

  In the prior art disclosed in Patent Document 2, the step 440 is formed on the side surface 430 of the semiconductor chip 403, thereby suppressing the adhesive 405 from scooping up the side surface 430 of the semiconductor chip 403.

  However, it is known that the semiconductor chip 403 separated by dicing is formed in a rectangular shape in plan view. Therefore, four corners where the side surfaces 430 intersect are formed in the semiconductor chip 403. Further, a concave ridge (not shown) is formed on the active surface 403a side by dicing on the stepped portion 440. Therefore, a narrow gap is formed on the inner peripheral surface of the concave ridges at the four corners.

  The adhesive 405 tends to gather at the four corners of the semiconductor chip 403 due to a capillary phenomenon or the like generated in the narrow gap. The adhesive 405 sometimes scoops up the side surface 430 of the semiconductor chip 403 from the corner where the adhesive 405 is gathered.

  By the way, in recent years, the pressure sensor has been miniaturized, so when the adhesive part of the pressure sensor is joined to a substrate member such as a package using an adhesive, the adhesive enters the center of the adhesive part. The problem of blocking the pressure introducing hole arranged at the central portion of the bonding portion is more likely to occur.

  An object of the present invention is to provide such a pressure sensor that prevents the adhesive from blocking the pressure introduction hole and a method for manufacturing the pressure sensor.

  The pressure sensor of the present invention includes a diaphragm that is sensitive to pressure, an adhesive portion that faces the diaphragm, and a pressure introduction hole that passes through the adhesive portion, and is a bottom surface that is located on the opposite side of the adhesive portion from the diaphragm. Is composed of a first surface on which the pressure introducing hole is disposed, and a second surface provided surrounding the first surface, and the first surface is projected from the second surface, The outer periphery of the first surface and the inner periphery of the second surface are smoothly connected curves that do not include a concave portion in plan view.

  Since the first surface protrudes from the second surface, a space is formed between the second surface and the substrate member when the adhesive portion is bonded to a substrate member such as a package with an adhesive. Is done. Since the adhesive flows into this space, the adhesive is prevented from leaking to the pressure introduction hole side.

  The first surface and the second surface, which are curves that smoothly connect to the bottom surface, which is the bonding surface of the bonding portion, not including the concave portion of the outer periphery of the first surface and the inner periphery of the second surface; Is formed. Therefore, since the concave portion is not formed on the side surface connected to the outer periphery of the first surface and the inner periphery of the second surface, the adhesive that has flowed into the space is collected locally by a capillary phenomenon or the like. In addition, the flow spreads uniformly along the outer periphery and the side surface connected to the inner periphery and does not gather locally. Therefore, leakage of the adhesive to the pressure introduction hole side is suppressed.

  Therefore, according to the present invention, it is possible to provide a pressure sensor that prevents the adhesive from blocking the pressure introduction hole.

  The pressure sensor includes a substrate member having an opening for introducing pressure, the pressure introduction hole and the opening are connected, and the pressure sensor and the substrate member are bonded using an adhesive. It is preferable to become.

  Since the first surface protrudes from the second surface, a space is formed between the second surface and the substrate member. Therefore, when the pressure sensor is joined to the substrate member using an adhesive, the adhesive flows into this space, and therefore the adhesive is prevented from leaking to the pressure introduction hole side.

  The bottom surface, which is an adhesive surface of the adhesive portion, includes the first surface and the second surface that are smoothly connected curves that do not include a concave portion on the outer periphery of the first surface and the inner periphery of the second surface. Is formed. Therefore, when the pressure sensor is bonded to the substrate member using an adhesive, the adhesive is prevented from closing the pressure introducing hole.

  It is preferable that the curved line has a circular shape, an elliptical shape, or a shape in which both ends of the straight line are connected to the circular arc.

  If it is such an aspect, the said curve will be a smoothly connected curve which does not contain the concave part.

It is preferable that a side surface connected to the first surface and the second surface is inclined.

  When the side surface is provided to be inclined, the surface area is larger than that provided vertically. When the surface area is large, the adhesive molecules adsorbed on the side surface increase. Therefore, more molecules of the adhesive pull other molecules in the adhesive to the side surface by intermolecular force. Therefore, the adhesive is pulled toward the side surface with a stronger force.

  Therefore, the adhesive is prevented from leaking to the pressure introduction hole side. Further, leakage to the outer peripheral surface of the side wall of the pressure sensor is suppressed.

  It is preferable that the side surface is inclined so that the inner periphery of the second surface is located closer to the through hole than the outer periphery of the first surface.

  In such an embodiment, a narrow gap is formed from the second surface and the side surface. A so-called capillary phenomenon in which molecules of the adhesive adsorbed on the second surface and the side surface pull other adhesive molecules with intermolecular force occurs in this narrow gap. Therefore, the adhesive is effectively suppressed from being pulled to the narrow gap side, entering the interface between the first surface and the member, and leaking to the pressure introducing hole side.

  It is preferable that a groove portion is provided on the first surface so as to surround the pressure introducing hole, and an inner periphery and an outer periphery of the groove portion are curves that smoothly connect without including a concave portion in a plan view.

  If it is such an aspect, the said adhesive will flow into the said groove part, and the said groove part becomes a pool of the said adhesive agent. And the said adhesive agent which flowed into the said groove part flows and spreads uniformly in the said smooth groove part which does not contain the part which becomes concave shape by planar view. Therefore, since the flowed-in adhesive does not collect at a local location in the groove, it is effectively suppressed that the flowed-in adhesive leaks to the pressure introducing hole side.

  It is preferable that the curved line has a circular shape, an elliptical shape, or a shape in which both ends of the straight line are connected to the circular arc.

If it is such an aspect, the said curve will be a smoothly connected curve which does not contain the concave part.

  It is preferable that a step portion is provided on the inner peripheral surface of the pressure introducing hole, and the front step portion has a surface facing the opposite side of the diaphragm.

  According to such an aspect, even if the adhesive enters the pressure introduction hole and crawls up along the inner peripheral surface of the pressure introduction hole, the step portion acts to stop the crawl. Therefore, it is suppressed that the pressure introducing hole is blocked by the adhesive.

  The first surface is preferably flat.

  With such an embodiment, it can be fixed in close contact with a flat substrate member such as a package.

  The pressure sensor manufacturing method of the present invention includes a diaphragm that is sensitive to pressure, an adhesive portion that faces the diaphragm, and a pressure introduction hole that penetrates the adhesive portion, and the adhesive portion is on the opposite side of the diaphragm. The bottom surface is composed of a first surface on which the pressure introducing hole is disposed, and a second surface provided to surround the first surface, and the first surface is protruded from the second surface. A pressure sensor comprising: a step (a) of forming an outer periphery of the first surface and an inner periphery of the second surface into a curved shape that smoothly connects without including a concave portion in plan view; A step (b) of dropping an adhesive on a substrate member having an opening to be introduced; a step (c) of placing the pressure sensor on the substrate member by connecting the pressure introduction hole to the opening; and The pressure-sensitive adhesive is cured on the substrate member. And step (d) of bonding the support, characterized in that it comprises a.

  If it is such an aspect, in the step (c), since the first surface protrudes from the second surface, a space is formed between the second surface and the substrate member. Since the adhesive flows into this space, the adhesive is prevented from leaking to the pressure introduction hole side.

  In the step (a), the first surface which is a smoothly connected curve that does not include a concave portion in the outer periphery of the first surface and the inner periphery of the second surface on the bottom surface which is an adhesive surface of the adhesive portion And the second surface are formed.

  Therefore, since the concave portion is not formed on the side surface connected to the outer periphery of the first surface and the inner periphery of the second surface, the adhesive flowing into the space in the step (c) is caused by a capillary phenomenon or the like. While not gathering locally, it spreads uniformly along the side surfaces connected to the outer periphery and the inner periphery, and does not gather locally.

  Therefore, in the step (c), the adhesive flows into the space and is prevented from leaking to the pressure introduction hole side, and the adhesive flowing into the space is not collected locally, so that the pressure Leakage to the introduction hole side is suppressed.

Then, in the step (d), the adhesive is cured and the pressure sensor is firmly bonded to the substrate member.
Therefore, according to the present invention, it is possible to provide a method for manufacturing a pressure sensor that prevents the adhesive from blocking the pressure introduction hole.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the pressure sensor which prevents that an adhesive block | closes a pressure introduction hole, and its manufacturing method.

1 is a schematic plan view of a pressure sensor according to a first embodiment. FIG. 2 is a schematic cross-sectional view taken along the line AA of the pressure sensor shown in FIG. 1 and viewed from the arrow direction. 1 is a schematic plan view of a pressure sensor according to a first embodiment viewed from below. It is a section schematic diagram showing the state where the pressure sensor of a 1st embodiment was joined to substrate members, such as a package. It is a section schematic diagram of the 1st modification in a 1st embodiment. It is a section schematic diagram of the 2nd modification in a 1st embodiment. 10 is a schematic plan view of a pressure sensor according to a third modified example of the first embodiment viewed from below. It is a plane schematic diagram which sees the pressure sensor of the 4th modification in a 1st embodiment from the lower part. It is a plane schematic diagram which looks at the pressure sensor of the 5th modification in a 1st embodiment from the lower direction. It is explanatory drawing of the manufacturing method of the pressure sensor in 1st Embodiment. 6 is a schematic plan view of a pressure sensor according to a second embodiment viewed from below. It is a section schematic diagram showing the state where the pressure sensor of a 2nd embodiment was joined to substrate members, such as a package. 10 is a schematic plan view of a pressure sensor according to a third embodiment viewed from below. 10 is a schematic plan view of a pressure sensor according to a fourth embodiment viewed from below. 10 is a schematic plan view of a pressure sensor according to a fifth embodiment viewed from below. It is a section schematic diagram showing the state where the pressure sensor of a 6th embodiment was joined to substrate members, such as a package. 1 is a schematic cross-sectional view of a semiconductor pressure sensor disclosed in Patent Document 1. 1 is a schematic plan view of a semiconductor pressure sensor disclosed in Patent Document 1. 1 is a schematic plan view of a semiconductor pressure sensor disclosed in Patent Document 1. 10 is a schematic cross-sectional view of a semiconductor chip disclosed in Patent Document 2.

  Regarding the pressure sensor shown in each figure, the Y direction is the left-right direction, the Y1 direction is the left direction, the Y2 direction is the right direction, the X direction is the front-rear direction, the X1 direction is the front direction, and the X2 direction is the rear direction. . Further, the direction orthogonal to both the X direction and the Y direction is the vertical direction (Z direction; height direction), the Z1 direction is the upward direction, and the Z2 direction is the downward direction. Each drawing is illustrated with dimensions appropriately changed for easy viewing.

<First Embodiment>
The first embodiment will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 1 is a schematic plan view of a pressure sensor according to the first embodiment. FIG. 2 is a schematic cross-sectional view taken along the line AA of the pressure sensor shown in FIG. 1 and viewed from the arrow direction. FIG. 3 is a schematic plan view of the pressure sensor according to the first embodiment viewed from below. FIG. 4 is a schematic cross-sectional view illustrating a state in which the pressure sensor according to the first embodiment is bonded to a substrate member such as a package.

  The pressure sensor 1 according to the first embodiment includes a sensor chip 2 that detects pressure by the diaphragm 2a being bent by an external pressure, and the electric resistance of the piezoresistive element provided in the diaphragm 2a is changed by this bending. And an adhesive portion 3 to which the chip 2 is bonded.

  In the present embodiment, the pressure sensor 1 is mounted on a blood pressure monitor, for example, and used as a gauge pressure sensor.

  In this embodiment, although it was used for the blood pressure monitor, it is not limited to this. For example, it can be used by being mounted on an air pressure gauge, a differential pressure gauge, a water pressure gauge, a hydraulic pressure gauge, an electronically controlled fuel injection device, or the like.

  The sensor chip 2 has a rectangular shape in plan view, and has a diaphragm 2a that is a disc shape in plan view that bends in response to pressure as a sensitive portion at the center of the upper surface thereof, and supports the diaphragm 2a from its periphery. And a side wall 2b. And this side wall 2b is joined on the adhesion part 3. FIG.

  The sensor chip 2 and the bonding portion 3 are both made of a silicon base material, and are formed by finely processing the silicon base material. And the sensor chip 2 and the adhesion part 3 are joined by diffusion bonding.

  A cavity 4 is formed surrounded by the sensor chip 2 and the bonding portion 3. A pressure introducing hole 3a for releasing the cavity 4 to atmospheric pressure is formed as a through hole in the vicinity of the center of the bonding portion 3. The pressure introduction hole 3 a is disposed, and a first surface 3 c that protrudes from the lower bottom surface 3 b that is the bonding surface of the bonding portion 3 is formed. A second surface 3d is formed on the lower bottom surface 3b of the bonding portion 3 so as to surround the first surface 3c.

  The first surface 3c and the second surface 3d are both substantially flat and substantially parallel to each other. The second surface 3d is positioned higher than the first surface 3c (Z2 direction), that is, on the diaphragm 2a side, and the first surface 3c is projected from the second surface 3d.

  Both the outer periphery 3f of the first surface 3c and the inner periphery 3g of the second surface 3d are formed in a circular shape. The side surface 3e connected to the first surface 3c and the second surface 3d is formed substantially perpendicular to the first surface 3c and the second surface 3d.

  In the present embodiment, the size of the pressure sensor 1 is, for example, about 0.5 mm × 0.5 mm in a plan view, and the height is about 0.2 mm. The inner diameter of the pressure introducing hole 3a is about 0.2 mm, the outer diameter of the first surface 3c is about 0.4 mm, and the distance separating the outer periphery 3f of the first surface 3c and the outer periphery of the pressure introducing hole 3a is 0. It is about 1 mm. Further, the height of the side surface 3e is about 0.05 mm.

  In the present embodiment, the pressure sensor 1 is mounted on, for example, a sphygmomanometer and used as a gauge pressure sensor, so that the cavity 4 is released to atmospheric pressure. And the blood pressure pressurized by the diaphragm 2a is measured on the basis of atmospheric pressure.

  In this embodiment, although the cavity 4 is open | released to atmospheric pressure, it is not limited to this. It is also possible to detect an external pressure with reference to another atmospheric pressure. At that time, the cavity 4 is released to the other atmospheric pressure.

  Since the pressure sensor 1 is housed in a package or the like and mounted on, for example, a blood pressure monitor, the pressure sensor 1 needs to be bonded to a substrate member 6 such as a package as shown in FIG. At that time, the adhesive 5 is dropped on a predetermined position of the substrate member 6. Next, the pressure sensor 1 is placed on the substrate member 6 so that the pressure introduction hole 3 a is connected to the opening 6 a that penetrates the substrate member 6. Then, for example, the adhesive 5 is cured by heating, and the adhesive portion 3 of the pressure sensor 1 is bonded to the substrate member 6.

The substrate member 6 is made of ceramics mainly composed of alumina (Al ₂ O ₃ ), for example. The adhesive 5 uses a liquid fluorine-based elastomer (SIFEL manufactured by Shin-Etsu Chemical Co., Ltd.).

In the present embodiment, the substrate member 6 is made of ceramics mainly composed of alumina, but is not limited to this. For example, ceramics mainly composed of silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), zirconia (ZrO ₂ ), or the like can be used.

  In this embodiment, although it was set as the liquid fluorine-type elastomer, it is not limited to this. Any material having an affinity for the bonding part 3 or the substrate member 6 can be used as the adhesive 5.

  In general, a bonding property between substances, that is, affinity is required between an adhesive and an adherend. The liquid fluorine-based elastomer has a silicon crosslinking reactive group. Therefore, the adhesive 5 made of a liquid fluorine-based elastomer has a good affinity with the bonding part 3 made of a silicon base material and the substrate member 6 made of ceramics mainly composed of alumina.

  However, if there is an affinity between the adhesive and the material to be bonded, the adhesive easily spreads on the surface of the material to be bonded, and also easily spreads on the interface where a plurality of materials to be bonded are in contact. Therefore, it is necessary to suppress this phenomenon when it is not desirable to spread to this interface and leak into the cavity or the like.

  When the pressure sensor 1 is joined to the substrate member 6, the adhesive 5 dripped at a predetermined position of the substrate member 6 spreads to the interface formed by the first surface 3c and the substrate member 6, and is directed to the pressure introduction hole 3a side. Leaking out was a challenge.

  In order to solve this problem, in the present embodiment, the first surface 3c protrudes from the second surface 3d, and the outer periphery 3f of the first surface 3c and the inner periphery 3g of the second surface 3d are formed in a circular shape. . Since the outer periphery 3f of the first surface 3c and the inner periphery 3g of the second surface 3d are formed in a circular shape, the side surface 3e formed between the outer periphery 3f and the inner periphery 3g is formed in a circular shape in plan view. The

  Since the first surface 3c protrudes from the second surface 3d, a space is formed between the second surface 3d and the substrate member 6 when the adhesive portion 3 is bonded to the substrate member 6 such as a package with the adhesive 5. 8 is formed. Since the adhesive 5 flows into the space 8, the adhesive 5 is prevented from leaking to the pressure introduction hole 3 a side.

  Since the side surface 3e constituting the side wall of the space 8 is formed in a circular shape in plan view, the side surface 3e does not include a concave portion in plan view. Therefore, the adhesive 5 flowing into the space 8 does not collect locally due to a capillary phenomenon or the like.

  Further, the side surface 3e constituting the side wall of the space 8 does not include a concave portion in a plan view and is connected smoothly, that is, without a corner portion. Therefore, the adhesive 5 that has flowed into the space 8 flows and spreads uniformly along the side surface 3e, and does not gather locally due to stagnation.

  In summary, the adhesive 5 is prevented from leaking to the pressure introduction hole 3 a side by flowing into the space 8. And since the adhesive 5 which flowed into the space 8 does not collect locally, it is suppressed that the adhesive 5 leaks out to the pressure introduction hole 3a side.

  However, if there are concave portions or corners on the side surface 3e in plan view, a region in which the flow becomes spiral is formed inside the concave portions or behind the corners. As a result, the adhesive 5 stagnates in this region, and the adhesive 5 is locally gathered in this region. Further, the adhesive 5 is attracted to the concave portion from the surroundings by a capillary phenomenon or the like. When the adhesive 5 gathers locally in this way, the adhesive 5 that has flowed into the space 8 enters the interface formed by the first surface 3c and the substrate member 6 from the space 8, and leaks out to the pressure introduction hole 3a side. It becomes easy.

  In the present embodiment, the side surface 3e is provided adjacent to the interface between the first surface 3c and the substrate member 6. Since the adhesive 5 and the side surface 3e have affinity, an intermolecular force that pulls between the molecule of the adhesive 5 and the side surface 3e works. Due to the intermolecular force, the molecules of the adhesive 5 are pulled and adsorbed to the side surface 3e. The molecules of the adhesive 5 adsorbed on the side surface 3e pull other molecules in the adhesive 5 toward the side surface 3e by the pulling intermolecular force acting between the molecules in the adhesive 5.

  Further, a surface tension acting along the surface is generated on the surface of the adhesive 5, and this surface tension pulls the adhesive 5 toward the side surface 3e.

  In this way, the adhesive 5 is pulled toward the side surface 3e and easily flows into the space 8, and the adhesive 5 that has flowed into the space 8 enters the interface between the first surface 3c and the substrate member 6 from the space 8. It is suppressed.

  Therefore, according to this embodiment, it is possible to provide the pressure sensor 1 that prevents the adhesive 5 from blocking the pressure introducing hole 3a.

  FIG. 5 shows a first modification of the first embodiment. In this modification, the side surface 3e is connected to be inclined with respect to the first surface 3c and the second surface 3d. The inclined side surface 3e can be provided with a larger surface area than the side surface 3e of the first embodiment provided substantially perpendicular to the first surface 3c and the second surface 3d.

  When the surface area of the side surface 3e is large, more molecules of the adhesive 5 are adsorbed on the side surface 3e. Therefore, more molecules of the adhesive 5 pull other molecules in the adhesive 5 toward the side surface 3e. Therefore, in the first modification, the adhesive 5 is pulled to the side surface 3e side with a stronger force than in the first embodiment.

  Therefore, according to the first modification, the adhesive 5 flows more easily into the space 8 than in the first embodiment, and the adhesive 5 that has flowed into the space 8 flows from the space 8 to the first surface 3c and the substrate. Intrusion into the interface formed by the member 6 is suppressed. Moreover, it is suppressed that the adhesive agent 5 leaks out to the outer peripheral surface 2c of a side wall, and scooping up the outer peripheral surface 2c of a side wall is prevented.

  FIG. 6 shows a second modification of the first embodiment. In this modification, the side surface 3e is inclined with respect to the first surface 3c and the second surface 3d so that the inner periphery 3g of the second surface 3d is located closer to the pressure introduction hole 3a than the outer periphery 3f of the first surface 3c. Are connected.

  The adhesive 5 goes up along the side surface 3e which inclines against gravity. When the side surface 3e is inclined, the gravity component along the side surface 3e that pulls the adhesive 5 downward is reduced. However, the intermolecular force by which the molecules of the adhesive 5 adsorbed on the side surface 3e pull other molecules in the adhesive 5 toward the side surface 3e does not change depending on the inclination of the side surface 3e. Therefore, by inclining the side surface 3e, the adhesive 5 is pulled with a strong force toward the side surface 3e.

  When the side surface 3e is tilted so that the inner periphery 3g is located closer to the center than the outer periphery 3f, a narrow gap is formed between the side surface 3e and the second surface 3d. The molecules of the adhesive 5 existing in the gap are pulled by the intermolecular force into the narrow gap by the molecules of the adhesive 5 adsorbed on the side surface 3e and the second surface 3d. This is a so-called capillary wrinkle phenomenon.

  Thus, according to the second modification, the adhesive 5 flows into the space 8 more easily than the first embodiment and the first modification, and the adhesive 5 that flows into the space 8 is Intrusion from the space 8 to the interface formed by the first surface 3c and the substrate member 6 is suppressed. Further, since the adhesive 5 is prevented from leaking to the outer peripheral surface 2c of the side wall as compared with the first embodiment and the first modification, it is possible to prevent the adhesive 5 from scooping up the outer peripheral surface 2c of the side wall.

  FIG. 7 shows a schematic plan view of the pressure sensor of the third modified example of the first embodiment viewed from below. In this modification, the side surface 3e is formed in an elliptical shape in plan view. That is, the side surface 3e does not include a concave portion in a plan view, and is formed smoothly, that is, without a corner portion. Moreover, although not shown in figure, the 1st surface 3c is protrudingly provided from the 2nd surface 3d.

  Therefore, when the pressure sensor 1 is bonded to the substrate member 6, the adhesive 5 flows into the space 8 formed between the second surface 3d and the substrate member 6, and the adhesive 5 leaks to the pressure introduction hole 3a side. It is suppressed from taking out.

  The adhesive 5 that has flowed into the space 8 spreads uniformly along the smooth side surface 3e that does not include a concave portion, and does not gather locally due to stagnation. Further, since there is no concave portion, the adhesive 5 does not gather locally from the surroundings due to capillary action or the like.

  FIG. 8 is a schematic plan view of a pressure sensor according to a fourth modification of the first embodiment viewed from below. In the present modification, the side surface 3e is formed in a curved shape including two straight lines and two outwardly bulging arcs in plan view. In addition, both ends of each straight line are connected to a circular arc. Since it is such an aspect, the side surface 3e of this modified example does not include a concave portion in plan view, and is formed smoothly, that is, in a shape having no corners. Moreover, although not shown in figure, the 1st surface 3c is protrudingly provided from the 2nd surface 3d.

  Therefore, when the pressure sensor 1 is bonded to the substrate member 6, the adhesive 5 flows into the space 8 formed between the second surface 3d and the substrate member 6, and the adhesive 5 leaks to the pressure introduction hole 3a side. It is suppressed from taking out.

  The adhesive 5 that has flowed into the space 8 spreads uniformly along the smooth side surface 3e that does not include a concave portion, and does not gather locally due to stagnation. Further, since there is no concave portion, the adhesive 5 does not gather locally from the surroundings due to capillary action or the like.

  FIG. 9 is a schematic plan view of the pressure sensor of the fifth modification example of the first embodiment viewed from below. In the present modification, the side surface 3e is formed in a curved shape including four straight lines and four outwardly arcs in plan view. In addition, both ends of each straight line are connected to a circular arc. Moreover, although not shown in figure, the 1st surface 3c is protrudingly provided from the 2nd surface 3d.

Therefore, when the pressure sensor 1 is joined to the substrate member 6, the adhesive 5 flows into the space 8 formed between the second surface 3d and the member 6, and the adhesive 5 leaks out to the pressure introduction hole 3a side. It is suppressed.

  The adhesive 5 that has flowed into the space 8 spreads uniformly along the smooth side surface 3e that does not include a concave portion, and does not gather locally due to stagnation. Further, since there is no concave portion, the adhesive 5 does not gather locally from the surroundings due to capillary action or the like.

  Thus, in the third modification, the fourth modification, and the fifth modification, the adhesive 5 flows into the space 8 formed between the second surface 3d and the substrate member 6, and the space Since the adhesive 5 that has flowed into 8 does not gather locally, the adhesive 5 is prevented from entering the interface formed by the first surface 3 c and the substrate member 6 from the space 8.

  The present invention is not limited to the fourth modification and the fifth modification, and a curve composed of three straight lines and three arcs, or a curve composed of a combination of four or more straight lines and four or more arcs is also possible. .

  FIG. 10 illustrates a manufacturing method of the pressure sensor according to the first embodiment. The sensor chip 2 and the bonding part 3 shown in FIG. 10A are formed in each by a semiconductor microfabrication technique using a silicon substrate. The silicon base material on which the sensor chip 2 is formed and the silicon base material on which the bonding portion 3 is formed are pressure-bonded under vacuum and at room temperature to diffuse silicon atoms between the silicon base materials. Are joined together. Next, the bonded silicon base material is cut by dicing or the like and separated into a plurality of pressure sensors 1.

  At that time, the region where the first surface 3c of the silicon base material is formed is covered with a photoresist layer, and the region where the second surface 3d is formed is etched by deep RIE (Deep Reactive Ion Etching) or the like, thereby forming the first surface. 3c is formed so as to protrude from the second surface 3d.

  However, as shown in FIGS. 5 and 6, it is difficult to obtain the shape in which the side surface 3e is inclined by etching the silicon substrate with deep RIE or the like. Therefore, in that case, the bonded portion 3 having the inclined side surface 3e is formed by cutting a ceramic member whose main component is alumina or the like. Then, Au or the like is formed on the bonding surface of the sensor chip 2 and the bonding portion 3 by sputtering, patterned with a photoresist film, and etched by RIE or the like to form an electrode layer. The layers are superposed and the sensor chip 2 and the bonding part 3 are joined by heating while being pressed.

  As shown in FIG. 10B, the adhesive 5 is dropped onto a predetermined position of the substrate member 6 by the dispenser 10 of the coating apparatus. In a later step, as shown in FIG. 10D, the bonding wire 11 is ultrasonically bonded to a pad electrode (not shown) on the surface of the sensor chip 2. It is preferable that the adhesive 5 is dropped just below the pad electrode.

  The adhesive 5 dropped just below the pad electrode spreads around the dropping point. Therefore, since the adhesive 5 is numerous just under the pad electrode, the bonding portion 3 and the substrate member 6 are more easily bonded firmly than other portions. Therefore, when the adhesive 5 is dropped directly below the portion where the bonding wire 11 is bonded, the ultrasonic vibration effectively acts on the interface between the bonding wire 11 and the pad electrode during ultrasonic bonding. As a result, the bonding between the bonding wire 11 and the pad electrode is strengthened, and the contact resistance can be reduced.

  Next, as shown in FIG. 10C, the pressure sensor 1 is placed on the substrate member 6 so that the pressure introducing hole 3a is connected to the opening 6a. And it heats for about 30 minutes-2 hours at the temperature of 100 to 250 degreeC. As a result, the adhesive 5 spreads and cures in the gap formed by the bonding portion 3 and the substrate member 6, whereby the pressure sensor 1 is firmly bonded to the substrate member 6.

  Next, as shown in FIG. 10D, a pad electrode (not shown) on the surface of the sensor chip 2 and an electrode such as an IC (Integrated Circuit) (not shown) mounted on the substrate member 6 are formed. They are electrically connected by bonding wires 11. As a result, the pressure data detected by the pressure sensor 1 is output to the IC or the like via the bonding wire 11.

  The pressure sensor 1 forms a bridge circuit with a plurality of piezoresistive elements and detects pressure. At that time, four pad electrodes are formed on the surface of the sensor chip 2 corresponding to the two output terminals, the power supply terminal, and the ground terminal.

  In the present embodiment, the pressure sensor is composed of a piezoresistive element, but the present invention is not limited to this. Strain resistance elements are also possible. In addition to an electric resistance type pressure sensor composed of a piezoresistive element or a strain resistance element, a capacitance type pressure sensor is also possible.

  FIG. 11 is a schematic plan view of the pressure sensor according to the second embodiment viewed from below. FIG. 12 is a schematic cross-sectional view showing a state in which the pressure sensor of the second embodiment is bonded to a substrate member such as a package. A second embodiment will be described with reference to FIGS. 11 and 12.

  In the second embodiment, the groove portion 7 is recessed in the first surface 3c so as to surround the pressure introducing hole 3a. And the inner periphery and outer periphery of this groove part 7 are circular shape by planar view.

  If it is such an aspect, the adhesive agent 5 will flow into the groove part 7, and the groove part 7 will become the pool of the adhesive agent 5. FIG. And since the inner periphery and outer periphery of the groove part 7 are formed in circular shape by planar view, the adhesive agent 5 which penetrate | invaded the groove part 7 flows and spreads uniformly in the groove part 7 without a corner part by planar view. Therefore, since the adhesive 5 does not collect at the local location in the groove part 7, it is effectively suppressed that the adhesive 5 leaks out to the pressure introduction hole 3a side.

  FIGS. 13, 14, and 15 are schematic plan views of the pressure sensor according to the third embodiment, the fourth embodiment, and the fifth embodiment, respectively, viewed from below. In all of the third embodiment, the fourth embodiment, and the fifth embodiment, the groove portion 7 is recessed in the first surface 3c so as to surround the pressure introduction hole 3a.

  And the inner periphery and outer periphery of the groove part 7 are each composed of an elliptical shape in plan view, two straight lines and two curved arcs that bulge outward, and four straight lines and four arcs that bulge outward. It is formed in a curve.

  Therefore, as in the second embodiment, the adhesive 5 flows into the groove 7, and the groove 7 serves as a pool of the adhesive 5. And the adhesive agent 5 which penetrate | invaded the groove part 7 flows and spreads uniformly in the groove part 7 without a corner | angular part by planar view. Therefore, since the adhesive 5 does not collect at the local location in the groove part 7, it is effectively suppressed that the adhesive 5 leaks out to the pressure introduction hole 3a side.

  FIG. 16 is a schematic sectional view showing a state in which the pressure sensor of the sixth embodiment is bonded to a substrate member such as a package. In this embodiment, the step part 12 is formed in the inner peripheral surface of the pressure introduction hole 3a, and the step part 12 has the surface 9 which faced the downward direction (Z1 direction).

  If it is such an aspect, even if the adhesive 5 penetrates into the pressure introducing hole 3a and crawls up along the inner peripheral surface of the pressure introducing hole 3a, the stepped portion 12 acts to stop the crawl. Therefore, it is suppressed that the pressure introduction hole 3a is blocked by the adhesive 5.

  In that case, it is preferable that the inner peripheral surface of the pressure introduction hole 3a located on the lower side of the surface 9 is a smoothly connected curve that does not include a concave portion in plan view.

DESCRIPTION OF SYMBOLS 1 Pressure sensor 2 Sensor chip 2a Diaphragm 2b Side wall 2c Outer peripheral surface of side wall 3 Adhesion part 3a Pressure introduction hole 3b Lower bottom surface 3c 1st surface 3d 2nd surface 3e Side surface 3f Outer periphery 3g Inner periphery 4 Cavity 5 Adhesive 6 Substrate member 6a Opening Part 7 groove part 8 space 9 surface 10 dispenser 11 bonding wire 12 step part

Claims (10)

A diaphragm sensitive to pressure,
An adhesive portion facing the diaphragm;
A pressure introducing hole penetrating the adhesive portion,
The bottom surface located on the opposite side of the adhesive portion from the diaphragm is composed of a first surface on which the pressure introducing hole is disposed, and a second surface provided to surround the first surface, and the first surface. Is projected from the second surface,
The pressure sensor, wherein the outer periphery of the first surface and the inner periphery of the second surface are smoothly connected curves that do not include a concave portion in plan view.   The pressure sensor includes a substrate member having an opening for introducing pressure, the pressure introduction hole and the opening are connected, and the pressure sensor and the substrate member are bonded using an adhesive. The pressure sensor according to claim 1, wherein   The said curve is circular shape, elliptical shape, or the shape which consists of a straight line and the circular arc which expanded outward, and the both ends of the said straight line are connected to the said circular arc, The Claim 1 or Claim characterized by the above-mentioned. 2. The pressure sensor according to 2.   4. The pressure sensor according to claim 1, wherein a side surface connected to the first surface and the second surface is inclined. 5.   5. The pressure sensor according to claim 4, wherein the side surface is inclined such that an inner periphery of the second surface is located closer to the through hole than an outer periphery of the first surface.   A groove portion is provided on the first surface so as to surround the pressure introduction hole, and an inner periphery and an outer periphery of the groove portion are curves that smoothly connect without including a concave portion in plan view. The pressure sensor according to any one of claims 1 to 5.   The said curve is circular shape, elliptical shape, or the shape which consists of a straight line and the circular arc swelled outward, and the both ends of the said straight line are connected to the said circular arc, The Claim 6 characterized by the above-mentioned. Pressure sensor.   8. The method according to claim 1, wherein a step portion is provided on an inner peripheral surface of the pressure introducing hole, and the front step portion has a surface facing the opposite side of the diaphragm. The pressure sensor described in 1.   The pressure sensor according to any one of claims 1 to 8, wherein the first surface is flat. A diaphragm sensitive to pressure,
An adhesive portion facing the diaphragm;
A pressure introducing hole penetrating the adhesive portion,
The bottom surface located on the opposite side of the adhesive portion from the diaphragm is composed of a first surface on which the pressure introducing hole is disposed, and a second surface provided to surround the first surface, and the first surface. Is a pressure sensor protruding from the second surface,
Forming the outer periphery of the first surface and the inner periphery of the second surface into a curved shape that is smoothly connected without a concave portion in plan view;
Applying an adhesive to the substrate member having an opening for introducing pressure (b);
A step (c) of connecting the pressure introduction hole to the opening and placing the pressure sensor on the substrate member;
A step (d) of curing the adhesive and bonding the pressure sensor to the substrate member;
A method for manufacturing a pressure sensor, comprising: