JP2000002608A - Semiconductor pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor high in yield in wire bonding and high in reliability in its joint. SOLUTION: A semiconductor sensor chip is housed in a body 10. A metal mold to mold a body 10 and a lead 15 simultaneously is provided with a protruded part for forming an opening in the body 10 and with a pair of column-shaped mold pins for every wire terminal part 16, which is one end part of the lead 15. The mold pin is rectangular in cross section and is in a shape to be in close contact with both longitudinal end parts of the back surface of the wire terminal part 16 so as to press the main surface of a wire terminal part 16 against the protruded part of the metal mold. Therefore, a pair of holes 17 corresponding to the shape of the mold pins are formed for every wire terminal part 16 in a mold produced by simultaneously molding the body 10 and the lead 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor.

[0002]

2. Description of the Related Art Conventionally, a semiconductor sensor chip 1 in which a strain detecting portion made of a piezo resistor is formed on a main surface side of a diaphragm portion of a semiconductor substrate is shown in FIGS.
There has been proposed a semiconductor pressure sensor housed in a housing composed of a housing 0 and a cover (not shown) covered by the body 10. The body 10 is box-shaped and has a synthetic resin (for example, PPS resin, PBT resin, L
A plurality of plate-like leads 15 are simultaneously formed by injection molding on a body main body 11 made of CP resin or the like.

As shown in FIG. 10, a mold 20 for simultaneously molding the body 10 and the lead 15 has a projection 21 for forming an opening in the body 10 and a wire terminal 16 formed by one end of the lead 15. The main surface is the shoulder 21a of the convex portion 21
Lead 15 near the wire terminal portion 16 so that
And a cylindrical mold pin (not shown) for holding the back surface of the mold. The mold 20 includes one mold pin for each lead 15. And the body 1
In 1, a concave portion 19 corresponding to the shape of the convex portion 21 is formed, and the surface closely contacting the distal end surface of the shoulder portion 21 a and the main surface of the wire terminal portion 16 are substantially flush. In short, the main surface of the wire terminal portion 16 is exposed inside the body 11. Here, in the illustrated example, the planar shape of the wire terminal portion 16 is formed in a rectangular shape. The portion where the mold pin was present during the simultaneous molding is a hole 17 formed in the body 11 from the rear surface of the body 11 to the back of the lead 15.

[0004] The main surface of the wire terminal section 16 and the pad 3 of the semiconductor sensor chip 1 are connected by a bonding wire W made of an ultrafine metal (for example, gold, aluminum, etc.) wire. The wire bonding step is generally performed by controlling the bonding apparatus by recognizing the image of the wire terminal section 16 by an automatic recognition apparatus having an image processing function.

[0005] A cylindrical pressure-introducing portion 14 having a pressure-introducing hole 14a communicating the inside and outside of the housing is continuously and integrally protruded from the bottom surface of the body 11, and a pressure-introducing hole is formed in one surface of the diaphragm. External pressure is transmitted through 14a.

[0006]

By the way, in the above-mentioned conventional structure, the body 10 and the lead 15 are formed at the same time. However, as shown in FIG. B) may occur. For this reason, when the image recognition of each wire terminal portion 16 is performed in the wire bonding step, the wire terminal portion 16 on which the burr 18 has not been generated is shown in FIG.
As shown in (a), since all four corners are recognized, wire bonding is normally performed.
11B, one of the four corner portions of the wire terminal portion 16 is not recognized as shown in FIG. 11B, for example, so that the yield of wire bonding is reduced. Here, in the latter case,
As shown in FIG. 12, the bonding wire W may be hit on the burr 18 and the bonding wire W
There is a problem that the reliability of the joint between the wire terminal 16 and the wire terminal 16 is reduced.

As an example in which burrs 18 are generated on the main surface of the wire terminal portion 16 as shown in FIG. 13, the wire terminal portion 16 is deformed by molding pressure as shown in FIG.
In the case where a gap is formed by being lifted from the shoulder portion 21a of the mold 20, if the thickness H of the lead 15 varies and the thickness H of the lead 15 is too thin as shown in FIG. The tip surface of the shoulder portion 21a (that is, the surface to be brought into contact with the main surface of the wire terminal portion 16) may be worn, or the molding injection pressure may vary.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor pressure sensor having a high yield rate of wire bonding and a highly reliable bonding portion.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor sensor chip having a strain detecting portion formed on a main surface side of a diaphragm portion of a semiconductor substrate, and an opening formed on one surface. A body made of a synthetic resin having at least a semiconductor sensor chip housed therein, a plate-shaped lead formed simultaneously with the body, a cover covered by the opening of the body, and one end of the lead exposed in the body. A semiconductor pressure sensor having a bonding wire connecting a main surface of a wire terminal portion and a pad of a semiconductor sensor chip, wherein a mold for simultaneously molding a body and a lead is provided.
A convex portion for forming the opening, and a mold pin for pressing a peripheral portion of a back surface of the wire terminal portion so that a main surface of the wire terminal portion is in close contact with the convex portion. Yes, when molding the body and the lead at the same time, the periphery of the back surface of the wire terminal is held down by the mold pin, so that the wire terminal can be prevented from floating due to the injection molding pressure. Even if the wire terminal portion has been deformed before, the deformation can be corrected by the mold pin and a gap can be prevented from being formed between the main surface of the wire terminal portion and the convex portion. It is possible to suppress the molding material from flowing out onto the main surface of the portion, thereby suppressing the occurrence of burrs, and consequently increasing the yield of wire bonding to the wire terminal portion, and It is possible to improve the reliability of the engaging portion,
The reliability of the entire sensor can be improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the mold pin is provided in a pair with the wire terminal portion and has a narrow cross-sectional shape. The exposure by the holes formed by the mold pins can be prevented, and the pressing strength of the wire terminal portion at the time of wire bonding can be increased, so that the yield of wire bonding can be further increased.

According to a third aspect of the present invention, there is provided a semiconductor sensor chip having a strain detecting portion formed on the main surface side of a diaphragm portion of a semiconductor substrate, and a synthetic resin having an opening on one surface and containing at least the semiconductor sensor chip. A body, a plate-like lead formed at the same time as the body, a cover covering the opening of the body, a main surface of a wire terminal portion including one end of the lead exposed in the body, and a pad of the semiconductor sensor chip. And a bonding wire for connecting the main body and the lead, wherein a mold for simultaneously molding the body and the lead is provided with a convex portion for forming the opening, and a main surface of a wire terminal portion provided with the convex portion. Mold pins that respectively press the corners on the back surface of the wire terminals so as to be in close contact with each other. By holding each corner on the back surface of the ear terminal with a mold pin, it is possible to prevent the wire terminal from floating due to injection molding pressure, and even if the wire terminal is deformed before simultaneous molding. Since the deformation is corrected by the mold pin and a gap is prevented from being formed between the main surface of the wire terminal portion and the convex portion, the molding material flows out onto the main surface of the wire terminal portion. And the occurrence of burrs can be suppressed. As a result, the yield of wire bonding to the wire terminal portion can be increased, and the reliability of the bonded portion can be increased. Can be enhanced. Moreover, since the mold pins only press the respective corner portions on the back surface of the wire terminal portion, it is possible to prevent the center portion of the back surface of the wire terminal portion from being exposed by the hole formed by the mold pin, and Since the pressing strength of the wire terminal portion at the time of bonding can be increased, the yield of wire bonding can be further increased.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the wire terminal portion includes a resistance reducing portion for smoothing the flow of the synthetic resin at the time of simultaneous molding with the body. It is possible to further suppress the wire terminal portion from rising from the convex portion of the mold due to the injection pressure of the molding material, and to further suppress the occurrence of burrs.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the resistance reducing portion is formed at a side edge of the wire terminal portion, and is formed at a central portion of the wire terminal portion from the main surface side to the back surface of the wire terminal portion. Is inclined so as to reduce the distance between the wire terminal portion and the main surface of the wire terminal portion, which is pressed by the injection pressure of the molding material made of synthetic resin against the convex portion of the mold. The formation of a gap between the main surface and the protrusion of the mold can be further suppressed, and the occurrence of burrs can be further suppressed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) The basic configuration of the present embodiment is substantially the same as the conventional configuration, and therefore, the same components as those of the conventional configuration are denoted by the same reference numerals and description thereof is omitted. By the way, in the conventional configuration, the mold 20 (see FIG. 10) for simultaneously molding the body 10 and the lead 15 has one column-shaped mold pin for each lead 15 (wire terminal portion 16). In the present embodiment, a pair of column-shaped mold pins is provided for each wire terminal portion 16. Here, the cross-sectional shape of the mold pin in the present embodiment is an elliptical shape, and the shape of the mold 20 is such that the planar shape is in close contact with both ends in the longitudinal direction of the back surface of the rectangular wire terminal portion 16. The main surface of the wire terminal 16 is pressed against the shoulder 21 a of the projection 21. Therefore, as shown in FIGS. 1 and 2, a molded product obtained by simultaneously molding the body 10 and the lead 15 has a pair of holes 17 corresponding to the shape of the mold pin for each wire terminal portion 16.
Is formed.

For this reason, in the present embodiment, when the body 10 and the lead 15 are simultaneously molded, the peripheral portion of the back surface of the wire terminal portion 16 is pressed by the mold pins, so that the wire terminal portion 16 is formed by injection molding pressure. Can be prevented from rising. Further, even if the wire terminal portion 16 is deformed before the simultaneous molding, the deformation is corrected by the mold pin, and a gap is formed between the main surface of the wire terminal portion 16 and the shoulder portion 21a of the convex portion 21. Can be prevented. Therefore, in the present embodiment, it is possible to suppress the molding material from flowing out onto the main surface of the wire terminal portion 16, and the burrs 18 (see FIG. 9)
Can be suppressed, the yield of wire bonding to the wire terminal portion 16 can be increased, the reliability of the joint can be improved, and the reliability of the sensor as a whole can be improved.

Further, since the mold pins are provided in a pair with respect to the wire terminal portion 16 and have a cross-sectional shape of an ellipse, the central portion of the back surface of the wire terminal portion 16 is prevented from being exposed by the hole 17. Since the pressing strength of the wire terminal portion 16 during wire bonding can be increased,
The yield of wire bonding can be further increased.

In the present embodiment, the cross-sectional shape of the mold pin is an ellipse. However, any shape may be used as long as it is long and narrow, for example, a rectangular shape or an elliptical shape.

(Embodiment 2) Since the basic configuration of this embodiment is substantially the same as the conventional configuration, the same components as those of the conventional configuration are denoted by the same reference numerals and description thereof is omitted. By the way, in the conventional configuration, a mold 20 (see FIG. 10) for simultaneously molding the body 11 and the lead 15 is provided with each lead 15 (the wire terminal portion 1).
6), one column-shaped mold pin is provided for each wire terminal portion. However, in the present embodiment, each of the wire terminal portions 16 has four column-shaped mold pins whose outer diameter is sufficiently smaller than that of the conventional mold pin. It has a mold pin. That is, 4 on the back surface of the wire terminal portion 16
It has a mold pin for holding each of the two corners. In short, the wire terminal portion 16 has a rectangular planar shape.
The main surface of the wire terminal portion 16 is pressed against the shoulder 21a of the projection 21 of the mold 20 in such a manner that the mold pins are brought into close contact with the respective corner portions on the back surface of the mold 20. Therefore, in the molded product in which the body 10 and the lead 15 are molded at the same time, as shown in FIGS. 3 and 4, four holes 17 corresponding to the shape of the mold pin are formed for each wire terminal portion 16.

For this reason, in the present embodiment, when the body 10 and the lead 15 are simultaneously molded, the peripheral portion of the back surface of the wire terminal portion 16 is pressed by four mold pins. The lifting of the terminal portion 16 can be prevented. Before the simultaneous molding, the wire terminal 1
Even if the wire terminal portion 6 is deformed, the deformation is corrected by the four mold pins abutting on the wire terminal portion 16 and the wire terminal portion 1 is deformed.
6 can be prevented from being formed between the main surface 6 and the shoulder 21a of the projection 21. Therefore, in the present embodiment, it is possible to suppress the molding material from flowing out onto the main surface of the wire terminal portion 16, thereby suppressing the generation of burrs 18 (see FIG. 9), and performing wire bonding to the wire terminal portion 16. And the reliability of the joint can be improved, and the reliability of the sensor as a whole can be improved.

The mold pins are connected to the respective wire terminals 16.
However, since the outer diameter of one wire is sufficiently smaller than that of the conventional structure, it is possible to prevent the central portion of the back surface of the wire terminal portion 16 from being exposed by the hole 17 and to perform wire bonding. Since the pressing strength of the wire terminal portion 16 at the time can be increased, the yield of wire bonding can be further increased.

In the present embodiment, the shape of the mold pin is cylindrical, but may be prismatic.

(Embodiment 3) The basic configuration of this embodiment is substantially the same as that of Embodiment 1 or Embodiment 2. As shown in FIG. 5 and FIG. The area is different. In the present embodiment, the side edge in the longitudinal direction of the wire terminal portion 16 parallel to the main flow direction of the molding material has a distance from the main surface side of the wire terminal portion 16 to the center of the wire terminal portion toward the back surface. It is formed in an inclined arc shape so as to be small. In the present embodiment, the side edges constitute a resistance reducing portion that smoothes the flow of the molding material when the body 10 and the lead 15 are simultaneously molded. Therefore, the molding material flows in the direction of arrows C ₁ and C _{2 in} FIG. 6 along the resistance reducing portion of the wire terminal portion 16 at the time of simultaneous molding, that is, the molding material from the side of the wire terminal portion 16 Since the wire flows to the back side of the portion 16, a force in the direction of arrow B in FIG. Wire terminal 1 by injection pressure of material
6 can be further suppressed from rising from the shoulder 21a of the convex portion 21 of the mold 20, and the occurrence of burrs 18 can be further suppressed.

In this embodiment, the wire terminal 16
Although the shape of the side edge is formed in an arc shape, a chamfered portion inclined in a straight line may be formed. Also, if a recess is formed in the shoulder 21a to avoid contact with the center of the main surface of the wire terminal 16, dust and the like adhere to the center of the main surface of the wire terminal 16 before simultaneous molding. Therefore, dust can be prevented from being crushed by the shoulder 21a of the mold 20, so that a scratch or the like can be prevented from being formed at the center of the main surface of the wire terminal portion 16, and the yield of wire bonding can be reduced. Can be increased.

[0024]

According to the first aspect of the present invention, there is provided a semiconductor sensor chip having a strain detecting portion formed on a main surface side of a diaphragm portion of a semiconductor substrate, and a synthetic resin having an opening on one surface and containing at least the semiconductor sensor chip. Body, a plate-shaped lead formed at the same time as the body, a cover covering the opening of the body, a main surface of a wire terminal portion including one end of the lead exposed in the body, and a semiconductor sensor chip. A semiconductor pressure sensor provided with a bonding wire for connecting the pad and the pad, wherein a mold for simultaneously molding the body and the lead includes a convex portion for forming the opening, and a main surface of the wire terminal portion. Since it has a mold pin for pressing the peripheral portion of the back surface of the wire terminal portion so as to be in close contact with the convex portion, the peripheral portion of the back surface of the wire terminal portion is formed when the body and the lead are simultaneously molded. By pressing with the mold pin, it is possible to prevent the wire terminal portion from being lifted by the injection molding pressure, and even if the wire terminal portion is deformed before the simultaneous molding, the deformation is corrected by the mold pin. Since it is possible to prevent a gap from being formed between the main surface of the wire terminal portion and the convex portion, it is possible to suppress the molding material from flowing out onto the main surface of the wire terminal portion, thereby suppressing generation of burrs. As a result, the yield of wire bonding to the wire terminal portion can be increased, and the reliability of the bonded portion can be increased, so that the reliability of the sensor as a whole can be increased. .

According to a second aspect of the present invention, in the first aspect of the invention, the mold pins are provided in a pair with respect to the wire terminal portion and have a narrow cross-sectional shape. Exposure can be prevented by the holes formed by the mold pins, and the pressing strength of the wire terminal portion at the time of wire bonding can be increased, so that the yield of wire bonding can be further increased. .

According to a third aspect of the present invention, there is provided a semiconductor sensor chip having a strain detecting portion formed on the main surface side of a diaphragm portion of a semiconductor substrate, and a synthetic resin having an opening on one surface and containing at least the semiconductor sensor chip. A body, a plate-like lead formed at the same time as the body, a cover covering the opening of the body, a main surface of a wire terminal portion including one end of the lead exposed in the body, and a pad of the semiconductor sensor chip. And a bonding wire for connecting the main body and the lead, wherein a mold for simultaneously molding the body and the lead is provided with a convex portion for forming the opening, and a main surface of a wire terminal portion provided with the convex portion. Mold pins that respectively press the corners on the back of the wire terminals so that they are in close contact with each other. By holding the corners with the mold pins, it is possible to prevent the wire terminals from being lifted up by the injection molding pressure.Also, even if the wire terminals are deformed before the simultaneous molding, the deformation is caused by the mold pins. Can be prevented from forming a gap between the main surface of the wire terminal portion and the convex portion, so that the molding material can be prevented from flowing out onto the main surface of the wire terminal portion and the burr can be suppressed. Can be suppressed, and as a result, the yield of wire bonding to the wire terminal portion can be increased, the reliability of the bonded portion can be increased, and the reliability of the sensor as a whole can be increased. This has the effect. Moreover, since the mold pins only press the respective corner portions on the back surface of the wire terminal portion, it is possible to prevent the center portion of the back surface of the wire terminal portion from being exposed by the hole formed by the mold pin, and Since the pressing strength of the wire terminal portion at the time of bonding can be increased, there is an effect that the yield of wire bonding can be further increased.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the wire terminal portion includes a resistance reducing portion for smoothing the flow of the synthetic resin at the time of simultaneous molding with the body. There is an effect that the wire terminal portion can be further prevented from rising from the convex portion of the mold due to the injection pressure of the molding material, and the occurrence of burrs can be further suppressed.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the resistance reducing portion is formed at a side edge of the wire terminal portion, and is formed at a central portion of the wire terminal portion from the main surface side to the rear surface of the wire terminal portion. Is inclined so as to reduce the distance between the wire terminal portion and the main surface of the wire terminal portion, which is pressed by the injection pressure of the molding material made of synthetic resin against the convex portion of the mold. It is possible to further suppress the formation of a gap between the main surface and the convex portion of the mold, and it is possible to further suppress the occurrence of burrs.

[Brief description of the drawings]

FIG. 1 shows the first embodiment and is a plan view of a body.

FIG. 2 is a perspective view showing the same and viewing the body from the rear surface side.

FIG. 3 shows the second embodiment and is a plan view of a body.

FIG. 4 is a perspective view showing the same and viewing the body from the rear side.

FIG. 5 is a perspective view of a main part of a third embodiment.

6 is a cross-sectional view of a main part when the body and the lead are molded at the same time, and corresponds to a cross section taken along line EE ′ of FIG. 5;

FIG. 7 is a perspective view showing a conventional example, in which a body is viewed from the front side with a cover removed.

FIG. 8 is a perspective view showing the above and viewing the body from the rear side.

9A and 9B show the same as the above, where FIG. 9A is a plan view of a body and FIG.
2 is a sectional view of FIG.

FIG. 10 is an explanatory diagram showing a die for simultaneously molding a body and a lead according to the first embodiment.

FIG. 11 is an explanatory diagram of a wire bonding step in the above.

FIG. 12 is a perspective view of a main part showing a defective product of the above.

FIG. 13 is an explanatory diagram of a cause of occurrence of a defective product according to the embodiment.

FIG. 14 is an explanatory diagram of another cause of occurrence of a defective product according to the embodiment.

FIG. 15 is an explanatory diagram of another cause of occurrence of a defective product according to the embodiment.

[Explanation of symbols]

 10 Body 15 Lead 16 Wire terminal 17 Hole

Claims (5)

[Claims] 1. A semiconductor sensor chip having a strain detecting portion formed on a main surface side of a diaphragm portion of a semiconductor substrate; a synthetic resin body having an opening on one surface and containing at least the semiconductor sensor chip; Bonding for connecting a plate-shaped lead formed at the same time, a cover covering the opening of the body, and a main surface of a wire terminal portion formed by one end of the lead exposed in the body to a pad of the semiconductor sensor chip. A semiconductor pressure sensor including a wire, wherein a mold for simultaneously molding a body and a lead is configured such that a convex portion for forming the opening and a main surface of a wire terminal portion are in close contact with the convex portion. A semiconductor pressure sensor comprising: a mold pin for pressing a peripheral portion of a back surface of the wire terminal portion. 2. The semiconductor pressure sensor according to claim 1, wherein said mold pin is provided in a pair with respect to a wire terminal portion and has a narrow cross section. 3. A semiconductor sensor chip having a strain detecting portion formed on a main surface side of a diaphragm portion of a semiconductor substrate; a synthetic resin body having an opening on one surface and containing at least the semiconductor sensor chip; Bonding for connecting a plate-shaped lead formed at the same time, a cover covering the opening of the body, and a main surface of a wire terminal portion formed by one end of the lead exposed in the body to a pad of the semiconductor sensor chip. A semiconductor pressure sensor including a wire, wherein a mold for simultaneously molding a body and a lead is configured such that a convex portion for forming the opening and a main surface of a wire terminal portion are in close contact with the convex portion. A semiconductor pressure sensor comprising: a mold pin for pressing a corner portion on a back surface of a wire terminal portion. 4. The semiconductor pressure according to claim 1, wherein said wire terminal portion includes a resistance reducing portion for smoothing the flow of the synthetic resin at the time of simultaneous molding with the body. Sensor. 5. The resistance reducing portion is formed at a side edge of the wire terminal portion and is inclined so as to reduce a distance from a main surface side of the wire terminal portion to a rear surface of the wire terminal portion and a central portion of the wire terminal portion. The semiconductor pressure sensor according to claim 4, wherein: