JP2001141589A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor capable of squaring easily a pressure introduction hole of a pressure sensor chip with the position of a through-hole of a holder, uniformizing the thickness of an adhesive, and of preventing the adhesive from penetrating into the through-hole of the holder. SOLUTION: A ring-shaped projection part 17G is formed on a recessed part 17B of the holder 17, and the pressure introduction hole 1A of the pressure sensor chip 1 is fitted with the ring-shaped projection part 17G and the pressure sensor chip 1 is installed, to compose this semiconductor pressure sensor 20. Positioning can be executed only by fitting the pressure introduction hole of the pressure sensor chip with a part of the ring-shaped projection part of the holder, therefore the pressure introduction hole of the pressure sensor chip can be easily squared with the position of the through-hole of the holder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor pressure sensor, and more particularly, to a semiconductor pressure sensor having a pressure sensor chip housed in a holder.

[0002]

2. Description of the Related Art For example, a semiconductor pressure sensor is known as a small pressure sensor capable of accurately detecting the pressure of a fluid. The structure of the semiconductor pressure sensor is as shown in FIG. That is, the semiconductor pressure sensor 10
Has a holder 7, in which the pressure sensor chip 1 is provided. This pressure sensor chip 1 includes:
A diaphragm 3 is provided in a silicon substrate 2 fixed on a pedestal 6 made of glass by anodic bonding, and a strain gauge is formed on the diaphragm 3. The strain gauge detects a strain or a stress generated in the diaphragm 3 by a pressure as a change in a resistance value. This strain gauge is connected to a terminal 5 by a wire 4. The pedestal 6 is provided with a pressure introduction port 1 </ b> A communicating with the diaphragm 3.

The holder 7 has a through hole 7A communicating with the pedestal 6.
Is provided. An adhesive 8 made of, for example, a silicone resin is provided on the bottom of the concave portion 7B serving as a storage portion of the holder 7.
Is applied, and the pressure sensor chip 1 is fixed by the adhesive 8. In such a semiconductor pressure sensor 10, when pressure is applied from the through hole 7A of the holder 7, distortion or stress corresponding to the amount is generated in the diaphragm 3,
By detecting this as a change in the resistance value, the pressure is measured.

Further, in a semiconductor pressure sensor as shown in FIG. 4, Japanese Patent Application Laid-Open Nos. 7-221222 and 9-12
No. 6925, JP-A-10-325768 and JP-A-9-126923, etc.
The gap between the pressure sensor chip and the holder is filled with adhesive by processing grooves or multiple protrusions on the pressure sensor chip mounting surface (joining surface) in the holder or the bottom surface (joining surface) of the pressure sensor chip. A pressure sensor having a different structure has been proposed.

[0005]

In the conventional semiconductor pressure sensor shown in FIG. 4, when the pressure sensor chip and the holder are bonded and fixed, first, a liquid adhesive is applied to the holder, and thereafter, The pressure sensor chip is fixed to the holder by placing the pressure sensor chip in such a manner that the pressure introduction port of the pressure sensor chip is aligned with the through hole of the holder, waiting for the adhesive to harden, and the adhesive is hardened. The pressure inlet of the chip communicates with the through-hole of the holder.

However, when the pressure sensor chip is mounted, since the position of the through hole of the holder is hidden by the diaphragm or the like, it is not possible to confirm the position of the pressure introducing port of the pedestal and the position of the through hole of the holder, and to match the positions. It is difficult to perform this operation, and thus a problem arises in that the pressure cannot be detected normally.

Further, when a liquid adhesive is used, not only does the position of the pressure sensor chip move before fixation, that is, before the adhesive is hardened,
There is a problem that the adhesive that has protruded by mounting the pressure sensor chip enters the pressure introduction port / through hole and closes it. Further, in the holder shape shown in FIG. 4, when a fluid adhesive is used, it is difficult to keep the adhesive thickness between the pressure sensor chip and the holder constant, and as a result, the adhesive strength varies. In addition, since the height of the surface of the pressure sensor chip (the surface on which the strain gauge is formed) is not constant, there is a problem that it is difficult to connect the strain gauge and the terminal using wire bonding.

Further, even when a groove for releasing an extra adhesive is formed on the pressure sensor chip mounting surface of the holder as disclosed in Japanese Patent Application Laid-Open No. 7-222222, the adhesive It is not constant, and therefore, similarly to the above, there is a problem that the connection between the strain gauge using the wire bonding and the terminal is difficult. In addition, Japanese Patent Application Laid-Open
As described in JP-A-126925, JP-A-10-325768 and JP-A-9-126923, a pressure sensor chip mounting surface (joining surface) in a holder or a bottom surface (joining surface) of a pressure sensor chip is provided. When a plurality of protrusions are formed, the protrusions make the gap between the pressure sensor chip and the holder constant, and the thickness of the adhesive filled between them becomes constant. When applying (usually using a dispenser or the like), air bubbles tend to adhere, and in this case, there is a problem that operations such as a defoaming step become complicated. In addition, if air bubbles remain in the adhesive, the reliability of bonding decreases. Furthermore, it is difficult to adjust the pressure sensor chip to an appropriate position of the holder (the pressure inlet of the holder and the through-hole of the pressure sensor chip coincide).

An object of the present invention is to make it possible to easily match the position of the pressure introduction port of the pressure sensor chip with the position of the through hole of the holder, and to make the thickness of the adhesive constant, and
An object of the present invention is to provide a semiconductor pressure sensor that can prevent an adhesive from entering a through hole of a holder.

[0010]

According to a first aspect of the present invention, a pressure inlet is provided in a bottom surface of a pressure sensor chip housed in a concave portion of a holder, and the bottom surface is joined to the holder to apply pressure to the pressure sensor chip. In the semiconductor pressure sensor to which the pressure is applied, an annular projection is formed in the concave portion of the holder, the annular projection projecting from the bottom thereof and partially fitting into the pressure inlet of the pressure sensor chip. And a through-hole communicating with the pressure inlet is formed.

According to the present invention, when assembling the semiconductor pressure sensor, the positioning can be performed only by fitting the pressure introduction port of the pressure sensor chip into a part of the annular projection formed with the through hole of the holder. The position of the pressure inlet of the pressure sensor chip and the position of the through hole of the holder can be easily matched. Also, since the through hole of the holder and the pressure introduction port of the pressure sensor chip are fitted, even if the adhesive used to adhere and fix the pressure sensor chip protrudes, it does not enter the through hole. Therefore, the through holes are not blocked. As a result, normal pressure detection becomes possible.

In the above, the joining of the pressure sensor chip to the holder is not limited to bonding. When the holder is made of, for example, resin, welding may be used. When the holder is made of, for example, metal, soldering or joining using a joining member or the like may be used.

According to a second aspect of the present invention, in the semiconductor pressure sensor according to the first aspect, the gap between the concave portion of the holder and the side surface of the pressure sensor chip is formed by at least two of the opposing portions of the concave portion of the holder. It is characterized in that it is a holding tool insertion space into which a holding tool for holding a chip can be inserted.

According to the present invention, when the pressure sensor chip is attached, the pressure sensor chip can be attached to the inside of the holder by grasping the pressure sensor chip with a grasping tool. It becomes easy to appropriately adjust the positional relationship of.

According to a third aspect of the present invention, in the semiconductor pressure sensor according to the first or second aspect, the bottom of the concave portion of the holder is formed to be recessed from the flat portion and adhered to the inside. A bottom portion of the pressure sensor chip, the bottom surface of the pressure sensor chip is partially mounted on a flat surface portion, and the remaining portion is joined by contacting an adhesive in the recess portion. It is.

In the present invention, since the adhesive is filled in the recess, the thickness of the adhesive can be made constant, and therefore, the variation in the adhesive strength can be prevented, and the pressure sensor chip can be made uniform. Can be fixed. Also, since part of the bottom surface of the pressure sensor chip is placed on a flat surface,
Due to the weight, the position of the pressure sensor chip does not move before the adhesive is cured.

In the above, examples of the adhesive include a thermosetting adhesive such as a silicone resin or a urethane resin, a thermoplastic adhesive such as polyvinyl acetate, and an elastomer adhesive such as neoprene. What is necessary is just to select and use suitably according to the etc.

According to a fourth aspect of the present invention, in the semiconductor pressure sensor according to any one of the first to third aspects, the tip of the annular projection projects from the upper surface of the flat portion. is there.

In the present invention, since the tip of the annular projection, that is, the tip of the through hole projects from the upper surface of the flat portion, it is located at a position higher than the recess filled with the adhesive. Will be. Therefore, even if the adhesive protrudes from the recess when the adhesive is filled in the recess, the adhesive does not enter the through-hole and block the through-hole.

According to a fifth aspect of the present invention, in the semiconductor pressure sensor according to any one of the first to fourth aspects, the concave portion of the holder has a rough surface.

In the present invention, since the concave portion of the holder has a rough surface, the adhesive easily adheres, and as a result, the pressure sensor chip can be firmly joined.

In the above description, the rough surface has a surface roughness of Ra5
It is preferably from 0 to 100 μm.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, only the portions different from the conventional semiconductor pressure sensor will be described in detail,
The same reference numerals are given to the other same members and the same structures, and the detailed description is omitted or simplified.

As shown in FIGS. 1A and 1B, the semiconductor pressure sensor 20 includes a holder 17 and the pressure sensor chip 1 housed and fixed in the holder 17. The holder 17 has a main body 17C formed in a planar quadrangular shape, and a stepped cylindrical portion 17D formed at one end in the thickness direction of the main body 17C. As shown in detail in FIGS. 2A and 2B, a concave portion 17B serving as a storage portion is formed inside the holder 17.

The concave portion 17B is a flat rectangular shape and is formed at a predetermined depth. The bottom portion 17H has a flat rectangular portion 17E and a concave portion 17F recessed by a predetermined size from the flat portion 17E. It is formed with. Depression 1
7F has a substantially square planar shape, and its diagonal line is orthogonal to the long side and the short side of the plane portion 17E. That is, the recess 17F is shifted by 90 ° with respect to the plane 17E. The recess 17F serves as an adhesive filling area, and the recess 17F is filled with a liquid adhesive 8 such as a silicone resin. The recess 17F has a surface roughness Ra50μ.
It has a rough surface of about m.

The recess 17B of the holder 17 has a bottom 17H.
An annular projection 17G projecting from the recess 17F is provided. The distal end surface of the annular projection 17G is formed in a flat shape, and is formed in a conical shape that spreads toward the recess 17F, and projects from the upper surface of the flat portion 17E by a predetermined dimension. The stepped cylindrical portion 1 of the holder 17
Inside 7D, a through-hole 17A penetrating the tip of the projection 17G of the recess 17B is formed. The tip of the through hole 17A has a smaller diameter than the other portions, and the narrow hole penetrates the annular projection 17G.

Further, the terminal 5 is provided on the holder 17 by being inserted above the main body 17C.
The three terminals 5 are arranged from the opposite side toward the long side of the concave portion 17B, and each end portion 5 extends to near the edge of the concave portion 17B.

The pressure sensor chip 1 housed and fixed in such a holder 17 is formed in a rectangular box shape, for example, a diaphragm 3 is formed on a silicon substrate 2 and an appropriate position on the diaphragm 3 with an insulating film interposed therebetween. And a strain gauge is arranged. Semiconductor thin films and metal thin films are used as the strain gauges. Also, the silicon substrate 2 has
A pedestal 6 made of perforated glass or the like is integrated by anodic bonding. The pedestal 6 of the pressure sensor chip 1 has a pressure inlet 1A communicating with the diaphragm 3. The distal end of the projection 17G of the holder 17 is fitted into the pressure inlet 1A.

The pressure sensor chip 1 is mounted on the upper surface of the plane portion 17E of the concave portion 17B, with each side of the chip 1 being parallel to each side of the concave portion 17B. That is, the chip 1 is arranged to be shifted by 90 ° with respect to the recess 17F. At this time, since the concave portion 17F is filled with the adhesive 8, a part of the bottom surface of the pressure sensor chip 1 is
7, the remaining portion of the bottom surface (the portion crossing the concave portion 17F) is in contact with the adhesive 8 filled in the concave portion 17F.

The distance between the two opposing side surfaces of the pressure sensor chip 1 and the concave portion 17B facing these side surfaces is a gap for inserting a gripper such as tweezers (not shown), for example, a dimension of 0.5 mm or more. And this gap forms a jig insertion space 18. Therefore, the pressure sensor chip 1 can be easily set at a predetermined position by inserting a gripping tool such as tweezers, and the position can be appropriately adjusted after the setting. Then, after the pressure sensor chip 1 is fixed by curing the adhesive 8, the strain gauge is connected to the terminal 5 by the wire 4.

According to the present embodiment, the following effects can be obtained. When mounting the pressure sensor chip 1, the through hole 1
Since the pressure inlet 1A of the pressure sensor chip 1 may be fitted to the annular projection 17G of the holder 17 in which 7A is formed, even if the through hole 17A is not visible for the chip 1,
The pressure sensor chip can be easily mounted, and thereby the alignment between the through hole of the holder and the pressure inlet of the pressure sensor chip becomes easy.

A through hole 17A is formed in the annular projection 17G of the holder 17, and the annular projection 17G and the pressure inlet 1A of the pressure sensor chip 1 are fitted. In this case, when a fluid adhesive is used, it is possible to prevent a problem that the protruding adhesive flows into the through-hole of the holder or the pressure introduction port of the pressure sensor chip and blocks each of them.

Since the jig insertion space 18 is provided in the concave portion 17B of the holder 17, it is possible to easily set the pressure sensor chip 1 at a predetermined position by inserting a gripping tool such as tweezers and to set the pressure sensor chip 1 at a predetermined position. , The position can be properly adjusted.

At the time of mounting the pressure sensor chip 1, the adhesive 8 is filled into the concave portion 17F constituting the bottom 17H of the holder 17, so that the thickness of the adhesive 8 becomes uniform. Variations in the adhesive strength between the holders 17 can be reduced.

Since the pressure sensor chip 1 is mounted on and fixed to the upper surface of the flat portion 17E constituting the bottom portion 17H of the concave portion 17B of the holder 17, the surface of the pressure sensor chip 1 (the surface on which the strain gauge is formed) is formed. The height can be constant. As a result, connection between the strain gauge and the terminal using wire bonding can be facilitated, and the reliability can be improved.

When mounting the pressure sensor chip 1,
Since the chip 1 is arranged with the corners shifted by 90 ° with respect to the recess 17F, the four corners of the recess 17F protrude from the side surface of the chip 1. Therefore, when the chip 1 is set at a predetermined position, the adhesive 8
Even if it flows out from 7F, since it flows from the part protruding from the side surface to the flat portion 17E, it can be prevented from flowing out to the annular projection 17G side.

The bottom surface of the adhesive filling area of the holder 17,
That is, since the surface roughness of the recessed portion 17F is a rough surface with a Ra of about 50 μm, the adhesive 8 easily adheres, and thus the adhesion between the pressure sensor chip 1 and the holder 17 can be strengthened.

It should be noted that the present invention is not limited to the above-described embodiment, but may be modified as follows as long as the object of the present invention can be achieved. For example, in the above-described embodiment, the recess 17F of the recess 17B that houses the pressure sensor chip 1 has a planar square shape, but is not limited thereto. As shown in FIG. 3, a circular recess 27F may be used, or another polygonal shape may be used.

In the above-described embodiment, the pressure sensor chip 1 is configured using the pedestal 6. However, the present invention is not limited to this, and the silicon chip having the diaphragm formed on the silicon substrate without using the pedestal is used. Only a configuration may be adopted. Further, in the above-described embodiment, a strain gauge type pressure sensor chip is used as the pressure sensor chip 1, but the pressure sensor chip 1 is not limited thereto, and may be a capacitance type pressure detecting element.

Further, in the above-described embodiment, the annular projection 17G formed on the bottom 17H of the recess 17B has a conical shape, but is not limited thereto, and may have a cylindrical shape.

[0041]

As described above, according to the semiconductor pressure sensor of the present invention, when assembling the semiconductor pressure sensor,
Positioning can be performed simply by fitting the pressure inlet of the pressure sensor chip to a part of the projection formed with the through hole of the holder, so that the position of the pressure inlet of the pressure sensor chip and the position of the through hole of the holder can be easily determined. Can be matched. Also, since the through hole of the holder and the pressure introduction port of the pressure sensor chip are fitted, even if the adhesive used to adhere and fix the pressure sensor chip protrudes, it does not enter the through hole. Therefore, the through holes are not blocked.
As a result, normal pressure detection becomes possible.

[Brief description of the drawings]

FIG. 1 shows a semiconductor pressure sensor according to an embodiment of the present invention, in which (A) is a longitudinal sectional view and (B) is a plan view.

2A and 2B show a holder of the semiconductor pressure sensor of the embodiment, wherein FIG. 2A is a longitudinal sectional view and FIG. 2B is a plan view.

FIG. 3 is a plan view showing a holder of a semiconductor pressure sensor according to a modification of the present invention.

FIG. 4 is a longitudinal sectional view showing a conventional semiconductor pressure sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure sensor chip 1A Pressure introduction port 2 Silicon substrate 3 Diaphragm 4 Wire 5 Terminal 6 Pedestal 8 Adhesive 17 Holder 17A Through-hole 17B Concave part 17C Main part 17D Stepped cylindrical part 17E Flat part 17F Depressed part 17G Annular projection Part 17H bottom

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA40 BB20 CC02 DD05 EE13 FF43 GG14 4M112 AA01 BA01 CA15 CA16 DA18 EA02 EA14 GA01 5F047 AA01 AB01 CA01 CB03

Claims (5)

[Claims] 1. A semiconductor pressure sensor, wherein a pressure inlet is provided on a bottom surface of a pressure sensor chip housed in a concave portion of a holder, and the bottom surface is joined to the holder to apply pressure to the pressure sensor chip. An annular projection is formed in the concave portion of the holder, the annular projection projecting from the bottom thereof and partially fitting into the pressure introduction port of the pressure sensor chip. A semiconductor pressure sensor, wherein a through-hole communicating with the pressure sensor is formed. 2. The semiconductor pressure sensor according to claim 1, wherein a gap between the concave portion of the holder and a side surface of the pressure sensor chip grips the pressure sensor chip at at least two portions opposed to the concave portion of the holder. A semiconductor pressure sensor having a gripper insertion space into which a gripper to be inserted can be inserted. 3. The semiconductor pressure sensor according to claim 1, wherein the bottom of the recess of the holder is formed with a flat portion and a recess from the flat portion, and the inside is filled with an adhesive. A bottom surface of the pressure sensor chip, a part of which is placed on the flat surface portion, and the remaining portion is joined by contacting with the adhesive in the recessed portion. . 4. The semiconductor pressure sensor according to claim 1, wherein a tip of said annular projection projects beyond an upper surface of said plane portion. 5. The semiconductor pressure sensor according to claim 1, wherein the depression of the holder has a rough surface.