JP2001066208A - Semiconductor pressure measuring device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an effect of a residual strain, to thin a film of a diaphragm and to improve a measuring accuracy and sensitivity characteristics, by bringing a polysilicon layer formed by a semiconductor process into contact with a silicon oxide film to connect the layer to the film. SOLUTION: One surface of a polysilicon layer 12 is brought into contact with one surface of a first single crystal silicon substrate 11, one surface of a silicon oxide film layer 13 is brought into contact with another surface of the layer 12, and the both are formed of a semiconductor process. One surface of a second single crystal silicon substrate 14 is brought into contact with another surface of the layer 13, and a diaphragm 15 is constituted of the layer 12 and the layer 13. Since the layer 12 is brought into contact with and connected to the layer 13, the layer 13 absorbs excess water so that a void is scarcely generated. Since the layer 13 is softened at 100 deg.C or higher even when a void exists, the voids are effectively deformed and embedded. Since a gap chamber 17 is provided, the layer 12 can be thinned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an inexpensive and accurate
The present invention relates to a semiconductor pressure measuring device having good sensitivity and overpressure characteristics, a stable manufacturing process, and little variation in characteristics, and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 6 is an explanatory view of a main part of a conventional example generally used in the prior art.
No. 879, entitled "Semiconductor Pressure Measuring Apparatus and Manufacturing Method Thereof". FIG. 7 is an explanatory view of the manufacturing process of FIG.

In FIG. 6, a polysilicon layer 2 has a first
And one surface thereof is in contact with one surface of the single crystal silicon substrate 1 and is formed by a semiconductor conductor process. The second single crystal silicon substrate 3 is provided with one surface in contact with the other surface of the polysilicon layer 2.

The recess 4 is provided on one surface side of the first single-crystal silicon substrate 1, a diaphragm 5 is formed on the first single-crystal silicon substrate 1, and the polysilicon layer 2 and the void space 6 are formed.
Is configured.

[0005] The distortion detection sensor 7 is provided on the diaphragm 5. In this case, for example, a piezoresistive strain gauge or a vibrating strain gauge with fixed beams at both ends is used.

[0006] The pressure guiding hole 8 is formed in the first single crystal silicon substrate 1.
From the other surface or from the other surface of the second single-crystal silicon substrate 3 to the gap chamber 6 to communicate the gap chamber 6 with the outside. In this case, the other surface of the second single-crystal silicon substrate 3 communicates with the cavity 6. In addition, the pressure guiding hole 8 may be communicated from the other surface of the first single-crystal silicon substrate 1 to the gap chamber 6, and of course, the gap chamber 6 may be communicated with the outside.

Such an apparatus is manufactured as follows, as shown in FIG. (A) As shown in FIG. 7A, a first silicon nitride film 102 is formed on a surface of a first single crystal silicon substrate 101. (B) As shown in FIG. 7 (b), the required cylindrical portion 103 of the first silicon nitride film 102 on the first single crystal silicon substrate 101 is removed by photolithography.

(C) As shown in FIG. 7C, the first single crystal silicon substrate 101 is oxidized to form a first silicon oxide film 104. (D) As shown in FIG. 7D, the first silicon oxide film 104 is removed.

(E) As shown in FIG. 7 (e), the surface of the first single-crystal silicon substrate 101 at a location 103 where the first silicon oxide film 104 has been removed and the first silicon nitride film 102 A second silicon nitride film 105 is formed on the surface.

(F) As shown in FIG. 7 (f), the second silicon nitride film 105 is removed by anisotropic etching. (G) As shown in FIG. 7 (g), the first single-crystal silicon substrate 101 where the second silicon nitride film 105 has been removed is oxidized to form a second silicon oxide film 106.

(H) As shown in FIG. 7H, the first silicon nitride film 102 and the second silicon nitride film 105 formed on the first single crystal silicon substrate 101 are removed. (I) As shown in FIG. 7I, a polysilicon layer 107 is formed on one surface of the first single crystal silicon substrate 101.

(J) As shown in FIG. 7 (j), the surface of the polysilicon layer 107 is flattened by polishing. (K) As shown in FIG. 7 (k), the surface of the first single crystal silicon substrate 101 on which the second silicon oxide film 106 is formed and the second single crystal silicon substrate 108 are joined.

(L) As shown in FIG. 7 (l), the first single-crystal silicon substrate 101 is polished except for the thickness of the diaphragm 5. (M) As shown in FIG. 7 (m), a distortion detection sensor 109 is formed on this diaphragm.

(N) As shown in FIG. 7 (n), a second silicon oxide film 106 is formed on a second single crystal silicon substrate 108.
Is formed. (O) As shown in FIG. 7 (o), the second silicon oxide film 10
6 from the hole 111 reaching to 6
The silicon oxide film 106 is removed.

As a result, diaphragm 5 is formed only of a silicon single crystal material. In other words, a diaphragm having no residual strain can be formed, the diaphragm can be further thinned, and a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity can be obtained.

[0016]

However, such a semiconductor pressure measuring device has the following problems. In order to directly join silicon, the surface step and the surface roughness after the completion of the polysilicon polishing in FIG. 7J are important.

In particular, in the direct bonding shown in FIG. 7 (k), since the silicon and polysilicon surfaces are bonded together, not only the steps but also the surface roughness must be made sufficiently small. Polishing of the polysilicon surface for reducing the surface roughness is more difficult than the polishing of the silicon surface due to the presence of grains, so that the polishing conditions are very difficult and the surface roughness varies greatly.

As a result, the bonding yield at room temperature depending on the surface roughness and the yield due to voids after heat treatment vary.

The present invention solves these problems. It is an object of the present invention to provide a semiconductor pressure measuring device which is inexpensive, has good accuracy, sensitivity, and high pressure characteristics, has a stable manufacturing process, and has little variation in characteristics, and a method of manufacturing the same.

[0020]

In order to achieve the above object, according to the present invention, in the semiconductor pressure measuring device according to the first aspect, a void space is provided on one surface side of the diaphragm and the other surface side of the diaphragm is provided. A semiconductor pressure measuring device in which a measuring pressure is applied to the first single crystal silicon substrate;
A polysilicon layer formed by a semiconductor process with one surface in contact with one surface of the first single-crystal silicon substrate; a silicon oxide film layer formed by a semiconductor process with one surface in contact with the other surface of the polysilicon layer; A second surface which is provided in contact with the other surface of the silicon film layer and forms a diaphragm together with the polysilicon layer and the silicon oxide film layer;
A single crystal silicon substrate, a concave portion provided on one surface side of the first single crystal silicon substrate to form a void space with the polysilicon layer, a strain detection sensor provided on the diaphragm, and the first single crystal silicon substrate. A pressure-guiding hole is provided which is communicated from the other surface of the crystalline silicon substrate or the other surface of the second single-crystal silicon substrate to the space, and communicates the space with the outside.

As a result, (1) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other and bonded, the semiconductor silicon oxide film layer absorbs excess water, so that the semiconductor is less likely to generate voids. A pressure measuring device is obtained.

(2) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other, 1100 ° C.
In the above, since the silicon oxide film layer is softened, there is an effect of deforming and filling even if a void exists. Further, a semiconductor pressure measuring device capable of taking in particles such as dust and eliminating voids can be obtained.

(3) In addition, since the void chamber is provided in the first silicon single crystal substrate, the polysilicon layer forming the diaphragm can be thinned. Specifically, for example, it can be 1 μm or less.

As a result, the influence of the residual strain of the polysilicon layer can be reduced, the diaphragm can be made thinner, and a semiconductor pressure measuring device with improved measurement accuracy and sensitivity characteristics can be obtained.

(4) In the manufacturing process, the second silicon oxide film forming the void chamber is buried in the first silicon single crystal substrate. In such a state, even if the thickness of the second silicon oxide film forming the void chamber is large, the thickness of the first silicon oxide film and the thickness of the second silicon oxide film can be optimized. The step between the silicon oxide film 2 and the first silicon single crystal substrate is, for example, specifically, for example,
It can be controlled to a step of 0.1 μm or less.

That is, even when the thickness of the second silicon oxide film forming the void chamber is increased to, for example, 1 μm or more, the step can be controlled to 0.1 μm or less. That is,
Since the gap in the gap chamber can be enlarged, even if fine foreign matter enters and adheres to the gap chamber, it can be used conveniently and a high yield can be obtained. Therefore, an inexpensive semiconductor pressure measuring device having stable characteristics can be obtained.

(5) Since the step can be reduced, the polysilicon layer for flattening can be thinned. For this reason, the polysilicon growth temperature of the polysilicon layer can be lowered, and the gray size can be reduced, so that the polishing process is facilitated. In addition, since the amount of polishing can be reduced, grinding is not required.

Further, since the variation in the thickness of the polysilicon layer within the wafer or between the wafers is reduced, the polishing operation is easy and simple, and an inexpensive semiconductor pressure measuring device can be obtained.

According to a second aspect of the present invention, there is provided a semiconductor pressure measuring device, wherein a void is provided on one surface of a diaphragm and a measurement pressure is applied to the other surface of the diaphragm. A crystalline silicon substrate, a polysilicon layer having one surface in contact with one surface of the first single crystal silicon substrate and formed by a semiconductor conductor process, and an oxidation layer having one surface in contact with the other surface of the polysilicon layer and being formed by a semiconductor conductor process. A silicon film layer, a second single crystal silicon substrate provided on one side in contact with the other surface of the silicon oxide film layer, and a first single crystal provided on one side of the first single crystal silicon substrate. A concave portion forming a diaphragm on a silicon substrate to form a void space with the polysilicon layer; a strain detection sensor provided on the diaphragm; Characterized by comprising a pressure guide hole that communicates with the other surface of the other surface or the second single-crystal silicon substrate con substrate to the gap chamber for communicating the the air gap chamber and the outside.

As a result, the diaphragm is formed only of the silicon single crystal material. In other words, a diaphragm having no residual strain can be formed, the diaphragm can be further thinned, and a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity can be obtained.

According to a third aspect of the present invention, there is provided a semiconductor pressure measuring apparatus, wherein a gap chamber is provided on one side of the diaphragm and a measurement pressure is applied to the other side of the diaphragm. A crystalline silicon substrate, a polysilicon layer having one surface in contact with one surface of the first single crystal silicon substrate and formed by a semiconductor conductor process, and an oxidation layer having one surface in contact with the other surface of the polysilicon layer and being formed by a semiconductor conductor process. A silicon film layer, a second single crystal silicon substrate which is provided so as to be in contact with the other surface of the silicon oxide film layer, and forms a diaphragm together with the polysilicon layer and the silicon oxide film layer; A concave portion provided on one surface side of the silicon substrate to form a void space with the polysilicon layer; and a concave portion provided on a portion where the bottom surface and the side surface of the concave portion are in contact with each other. And a strain detection sensor provided on the diaphragm, and the other surface of the first single-crystal silicon substrate or the other surface of the second single-crystal silicon substrate communicates with the gap chamber to communicate with the gap chamber and the outside. And a pressure-guiding hole communicating with

As a result, since the rounded portion is provided at the edge portion of the void space, even when a large pressure is applied to the void space, there is no portion where the stress generated at the edge portion of the void space is concentrated. Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

According to a fourth aspect of the present invention, there is provided a semiconductor pressure measuring device, wherein a gap chamber is provided on one surface side of the diaphragm and a measurement pressure is applied to the other surface side of the diaphragm. A crystalline silicon substrate, a polysilicon layer having one surface in contact with one surface of the first single crystal silicon substrate and formed by a semiconductor conductor process, and an oxidation layer having one surface in contact with the other surface of the polysilicon layer and being formed by a semiconductor conductor process. A silicon film layer, a second single crystal silicon substrate provided on one side in contact with the other surface of the silicon oxide film layer, and a first single crystal provided on one side of the first single crystal silicon substrate. A concave portion forming a diaphragm on a silicon substrate to form a void space with the polysilicon layer, a round portion provided at a portion where a bottom surface and a side surface of the concave portion are in contact with each other, A strain detection sensor provided in the afram and a conductor communicating from the other surface of the first single-crystal silicon substrate or the other surface of the second single-crystal silicon substrate to the gap chamber and communicating the gap chamber with the outside. And a pressure hole.

As a result, the diaphragm is formed only of the silicon single crystal material. In other words, a diaphragm having no residual strain can be formed, the diaphragm can be further thinned, and a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity can be obtained.

Further, since the rounded portion is provided at the edge of the gap chamber, there is no portion where the stress generated at the edge of the gap is concentrated even when a large pressure is applied to the gap chamber. Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

According to a fifth aspect of the present invention, in the semiconductor pressure measuring device according to the first or third aspect, the diaphragm is formed of the polysilicon layer, the silicon oxide film layer, the second single crystal silicon substrate, Characterized by being formed by at least one of the following.

As a result, the semiconductor pressure measuring device can be used properly depending on the application of the semiconductor pressure measuring device, and a semiconductor pressure measuring device having a high degree of freedom for the application can be obtained.

A method of manufacturing a semiconductor pressure measuring device according to claim 6 of the present invention, comprising the following steps. (A) forming a first silicon nitride film on the surface of the first single-crystal silicon substrate; (B) removing a required portion of the first silicon nitride film on the first single crystal silicon substrate by photolithography; (C) a step of oxidizing the first single crystal silicon substrate to form a first silicon oxide film. (D) removing the first silicon oxide film. (E) forming a second silicon nitride film on the surface of the first single viscous silicon substrate and the surface of the first silicon nitride film where the first silicon oxide film has been removed; (F) removing the second silicon nitride film by anisotropic etching. (G) forming a second silicon oxide film by oxidizing the first single crystal silicon substrate at the location where the second silicon nitride film has been removed; (H) removing the first silicon nitride film and the second silicon nitride film formed on the first single crystal silicon substrate. (I) forming a polysilicon layer on one surface of the first single crystal silicon substrate; (J) a step of flattening the surface of the polysilicon layer by polishing; (K) forming a third silicon oxide film on one surface of the second single crystal silicon substrate; (L) a step of bonding a polysilicon layer surface of the first single-crystal silicon substrate to a third silicon oxide film of the second single-crystal silicon substrate. (M) a step of polishing the first or second single-crystal silicon substrate while keeping the thickness of the diaphragm. (N) forming a strain detection sensor on the diaphragm; (O) forming a hole reaching the second silicon oxide film in the first or second single crystal silicon substrate; (P) removing the second silicon oxide film by selective etching from a hole reaching the second silicon oxide film.

As a result, (1) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other and bonded, the thermal silicon oxide film layer absorbs excess water, so that a semiconductor hardly generates voids. A method for manufacturing a pressure measuring device is obtained.

(2) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other, the temperature is set at 1100 ° C.
In the above, since the silicon oxide film layer is softened, there is an effect of deforming and filling even if a void exists.

Further, a method of manufacturing a semiconductor pressure measuring device capable of taking in particles such as dust and eliminating voids is obtained. (3) As shown in step (h), the second silicon oxide film forming the void chamber is in a state of being embedded in the first silicon single crystal substrate.

In such a state, even if the thickness of the second silicon oxide film forming the void space becomes large, the thickness of the first silicon oxide film and the thickness of the second silicon oxide film can be optimized. For example, the step between the second silicon oxide film and the first silicon single crystal substrate in the step (h) is specifically, for example,
It can be controlled to a step of 0.1 μm or less.

That is, even when the thickness of the second silicon oxide film forming the void chamber is increased to, for example, 1 μm or more, the step can be controlled to 0.1 μm or less. That is,
Since the gap in the gap chamber can be enlarged, even if fine foreign matter enters and adheres to the gap chamber, it can be used and a high yield can be obtained. Therefore, a method for manufacturing an inexpensive semiconductor pressure measuring device having stable characteristics can be obtained.

(4) Since the step can be reduced, the polysilicon layer for flattening can be made thinner. For this reason, the polysilicon growth temperature of the polysilicon layer can be lowered, and the gray size can be reduced, so that the polishing process is facilitated. In addition, since the amount of polishing can be reduced, grinding is not required.

In addition, since the variation in the thickness of the polysilicon layer within the wafer or between the wafers is reduced, the polishing operation is easy and simple, and a method for manufacturing an inexpensive semiconductor pressure measuring device can be obtained. Hereinafter, a detailed description will be given based on embodiments.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a main part of an embodiment of the present invention, and FIG. 2 is an explanatory view of a manufacturing process of FIG.

In the figure, the polysilicon layer 12 is
One surface is in contact with one surface of the single crystal silicon substrate 11 and is formed by a semiconductor conductor process. The silicon oxide film layer 13 has one surface in contact with the other surface of the polysilicon layer 12 and is formed by a semiconductor process.

The second single-crystal silicon substrate 14 is provided with one surface in contact with the other surface of the silicon oxide film layer 13 to form a diaphragm 15 together with the polysilicon layer 12 and the silicon oxide film layer 13.

The recess 16 is formed on the first single crystal silicon substrate 1.
1, the polysilicon layer 12 and the cavity 1
7 is formed. The strain detecting element 18 is provided on the diaphragm 15. In this case, for example, a piezoresistive strain gauge or a vibrating strain gauge with fixed beams at both ends is used.

In this case, the pressure guiding hole 19 is
From the other surface of the first single crystal silicon substrate 11,
And the gap chamber 17 and the outside.

In this case, the first single crystal silicon substrate 1
1 communicates with the cavity 17 from the other side. In addition, the pressure-guiding hole 19 may be communicated from the other surface of the second single-crystal silicon substrate 14 to the cavity 17, and of course, the cavity 17 may be communicated with the outside.

Such an apparatus is manufactured as follows, as shown in FIG. (A) As shown in FIG. 2A, a first silicon nitride film 202 is formed on a surface of a first single crystal silicon substrate 201. (B) As shown in FIG. 2 (b), a required cylindrical portion 203 of the first silicon nitride film 202 on the first single crystal silicon substrate 201 is removed by photolithography.

(C) As shown in FIG. 2C, the first single-crystal silicon substrate 201 is oxidized to form a first silicon oxide film 204 at a required position 203. (D) As shown in FIG. 2D, the first silicon oxide film 204 is removed.

(E) As shown in FIG. 2 (e), the surface of the first single crystal silicon substrate 201 at the position 203 where the first silicon oxide film 204 has been removed and the first silicon nitride film 202 A second silicon nitride film 205 is formed on the surface.

(F) As shown in FIG. 2F, the second silicon nitride film 205 is removed by anisotropic etching. (G) As shown in FIG. 2 (g), the first single crystal silicon substrate 201 where the second silicon nitride film 205 is removed is oxidized to form a second silicon oxide film 206.

(H) As shown in FIG. 2H, the first silicon nitride film 202 and the second silicon nitride film 205 formed on the first single crystal silicon substrate 201 are removed. (I) As shown in FIG. 2 (i), a polysilicon layer 207 is formed on one surface of the first single crystal silicon substrate 201.

(J) As shown in FIG. 2 (j), the surface of the polysilicon layer 207 is flattened by polishing. (K) As shown in FIG. 2K, a third silicon oxide film 209 is formed on one surface of the second single crystal silicon substrate 208.

(L) As shown in FIG. 2 (l), the polysilicon layer surface 207 of the first single crystal silicon
Third silicon oxide film 2 on single crystal silicon substrate 208
09 and bonding.

(M) As shown in FIG. 2 (m), the second single crystal silicon substrate 208 is polished while leaving the thickness of the diaphragm 15. (N) As shown in FIG.
Next, a distortion detection sensor 211 is formed.

(O) As shown in FIG. 2 (o), a second silicon oxide film 206 is formed on a first single crystal silicon substrate 201.
Is formed. (P) As shown in FIG. 2 (p), the second silicon oxide film 2
The second silicon oxide film 206 is removed by selective etching from the hole 212 reaching 06.

As a result, (1) the polysilicon layer 12 and the silicon oxide film 13
Since the thermal oxidation silicon film 13 absorbs excess water, a semiconductor pressure measurement device in which voids are unlikely to be generated can be obtained.

(2) Since the polysilicon layer 12 and the silicon oxide film layer 13 are contacted and joined,
At a temperature of 100 ° C. or higher, the silicon oxide film layer 13 is softened, so that there is an effect of deforming and filling even if a void exists. Further, a semiconductor pressure measuring device capable of taking in particles such as dust and eliminating voids can be obtained.

(3) In addition, since the void space 17 is provided in the first silicon single crystal substrate 11, the diaphragm 1
5 can be made thinner. Specifically, for example, it can be 1 μm or less.

As a result, the influence of the residual strain of the polysilicon layer 12 can be reduced, the thickness of the diaphragm 15 can be reduced, and a semiconductor pressure measuring device with improved measurement accuracy and sensitivity characteristics can be obtained.

(4) As shown in FIG.
The second silicon oxide film 206 forming 7 is buried in the first silicon single crystal substrate 201.

In such a state, even if the thickness of the second silicon oxide film 206 forming the void space 17 increases, the thickness of the first silicon oxide film 204 and the thickness of the second silicon oxide film 206 increase. Is optimized, the step between the second silicon oxide film 206 and the first silicon single crystal substrate 201 in FIG. 2H is specifically controlled to, for example, a step of 0.1 μm or less. You can do it.

That is, even when the thickness of the second silicon oxide film 206 forming the void space 17 is increased to, for example, 1 μm or more, the step can be controlled to 0.1 μm or less. That is, since the gap of the gap chamber 17 can be enlarged, even if fine foreign matter enters and adheres to the gap chamber 17, it can be used conveniently and a high yield can be obtained. Therefore, an inexpensive semiconductor pressure measuring device having stable characteristics can be obtained.

(5) Since the step can be reduced, the polysilicon layer 207 for flattening can be thinned.
For this reason, the polysilicon growth temperature of the polysilicon layer 207 can be lowered, and the gray size can be reduced, so that the polishing process is facilitated. In addition, since the amount of polishing can be reduced, grinding is not required.

Further, since the variation in the thickness of the polysilicon layer 207 within the wafer or between the wafers is reduced, the polishing operation is easy and simple, and an inexpensive semiconductor pressure measuring device can be obtained.

FIG. 3 is an explanatory view of a main part configuration of another embodiment of the present invention. In this embodiment, the polysilicon layer 22 is
One surface is in contact with one surface of the first single crystal silicon substrate 21, and is formed by a semiconductor conductor process.

The silicon oxide film layer 23 has one surface in contact with the other surface of the polysilicon layer 22 and is formed by a semiconductor conductor process. The second single crystal silicon substrate 24 is provided with one surface in contact with the other surface of the silicon oxide film layer 23.

The recess 25 is formed in the first single crystal silicon substrate 2
1 provided on one surface side of the first monocrystalline silicon substrate 21
Is formed to form the polysilicon layer 22 and the void space 27.

The strain detection sensor 28 is provided on the diaphragm 26. The pressure guiding hole 29 is communicated from the other surface of the second single crystal silicon substrate 24 to the cavity 27, and communicates the cavity 27 with the outside.

As a result, diaphragm 26 is formed only of a silicon single crystal material. That is, it is possible to form a diaphragm having no residual strain, to further reduce the thickness of the diaphragm 26, and to obtain a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity.

FIG. 4 is an explanatory diagram of a main part configuration of another embodiment of the present invention. In this embodiment, the polysilicon layer 32
Is formed in contact with one surface of the first single crystal silicon substrate 31 by a semiconductor conductor process. One surface of the silicon oxide film layer 33 is in contact with the other surface of the polysilicon layer 32, and is formed by a semiconductor conductor process.

The second single crystal silicon substrate 34 is provided with one surface in contact with the other surface of the silicon oxide film layer 33, and forms a diaphragm 35 together with the polysilicon layer 32 and the silicon oxide film layer 33.

The recess 36 is formed in the first single crystal silicon substrate 3
1, the polysilicon layer 32 and the cavity 3
7 are formed. The rounded portion 361 is formed on the bottom surface 3 of the concave portion.
It is provided at a portion where 62 and side surface 363 are in contact.

The strain detection sensor 38 is provided on the diaphragm 35. In this case, the pressure guiding hole 39 is communicated from the other surface of the first single crystal silicon substrate 31 to the cavity 37, and communicates the cavity 37 with the outside.

As a result, since the rounded portion 361 is provided at the edge of the gap chamber 37, even when a large pressure is applied to the gap chamber 37, there is no portion where the stress generated at the edge of the gap chamber 37 is concentrated. . Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention. In this embodiment, the polysilicon layer 42
Is formed in contact with one surface of the first single crystal silicon substrate 41 by a semiconductor conductor process.

The silicon oxide film layer 43 has one surface in contact with the other surface of the polysilicon layer 42 and is formed by a semiconductor conductor process. The second single crystal silicon substrate 44 is provided with one surface in contact with the other surface of the silicon oxide film layer 43.

The recess 45 is formed in the first single crystal silicon substrate 4
1, a first single-crystal silicon substrate 41
A diaphragm 46 is formed on the substrate to form a polysilicon layer 42 and a cavity 47.

The round portion 451 is provided at a portion where the bottom surface 452 and the side surface 453 of the concave portion 45 are in contact. The strain detection sensor 48 is provided on the diaphragm 46. In this case, the pressure introducing hole 49 is formed in the second single crystal silicon substrate 44.
The other side communicates with the cavity 47, and the cavity 47 communicates with the outside.

As a result, the diaphragm 46 is formed only of the silicon single crystal material. That is, it is possible to form a diaphragm having no residual strain, and it is possible to further reduce the thickness of the diaphragm 46, and to obtain a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity.

Further, the rounded portion 4 is formed at the edge of the space 47.
Due to the presence of 51, even when a large pressure is applied to the cavity 47, there is no portion where the stress generated at the edge of the cavity 47 is concentrated. Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

In the above-described embodiment, the diaphragms 15 and 35 are formed of the polysilicon layers 12 and 32, the silicon oxide film layers 13 and 33, and the second single-crystal silicon substrate
34, but the present invention is not limited to this.

For example, only the polysilicon layers 12 and 32 may be used. In short, the diaphragms 15 and 35 are formed of the polysilicon layers 12 and 32, the silicon oxide film layers 13 and 33, and the second single-crystal silicon substrates 14 and 35. at least
What is necessary is just to be formed by one piece. In short, unnecessary layers in the diaphragms 15 and 35 can be easily removed by etching.

In this case, the semiconductor pressure measuring device can be used properly depending on the application of the semiconductor pressure measuring device, and a semiconductor pressure measuring device having a high degree of freedom for the application can be obtained.

The foregoing description merely illustrates certain preferred embodiments for purposes of explanation and illustration of the invention. Therefore, the present invention is not limited to the above-described embodiment, but includes many more changes and modifications without departing from the essence thereof.

[0090]

As described above, according to the present invention,
According to the above, (1) Since the polysilicon layer and the silicon oxide film layer are made to be in contact with each other, the semiconductor silicon oxide film layer absorbs excessive water, so that the semiconductor pressure measurement in which voids are unlikely to be generated. A device is obtained.

(2) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other, the temperature is set at 1100 ° C.
In the above, since the silicon oxide film layer is softened, there is an effect of deforming and filling even if a void exists. Further, a semiconductor pressure measuring device capable of taking in particles such as dust and eliminating voids can be obtained.

(3) In addition, since the void chamber is provided in the first silicon single crystal substrate, the thickness of the polysilicon layer forming the diaphragm can be reduced. Specifically, for example, it can be 1 μm or less.

As a result, the influence of the residual strain of the polysilicon layer can be reduced, the thickness of the diaphragm can be reduced, and a semiconductor pressure measuring device with improved measurement accuracy and sensitivity characteristics can be obtained.

(4) In the manufacturing process, the second silicon oxide film that forms the void space is buried in the first silicon single crystal substrate. In such a state, even if the thickness of the second silicon oxide film forming the void chamber is large, the thickness of the first silicon oxide film and the thickness of the second silicon oxide film can be optimized. The step between the silicon oxide film 2 and the first silicon single crystal substrate is, for example, specifically, for example,
It can be controlled to a step of 0.1 μm or less.

That is, even when the thickness of the second silicon oxide film forming the void chamber is increased to, for example, 1 μm or more, the step can be controlled to 0.1 μm or less. That is,
Since the gap in the gap chamber can be enlarged, even if fine foreign matter enters and adheres to the gap chamber, it can be used conveniently and a high yield can be obtained. Therefore, an inexpensive semiconductor pressure measuring device having stable characteristics can be obtained.

(5) Since the step can be reduced, the polysilicon layer for flattening can be thinned. For this reason, the polysilicon growth temperature of the polysilicon layer can be lowered, and the gray size can be reduced, so that the polishing process is facilitated. In addition, since the amount of polishing can be reduced, grinding is not required.

Further, since the variation in the thickness of the polysilicon layer within the wafer or between the wafers is reduced, the polishing operation is easy and simple, and an inexpensive semiconductor pressure measuring device can be obtained.

According to the second aspect of the present invention, the diaphragm is formed only of a silicon single crystal material. That is,
A diaphragm having no residual strain can be formed, the diaphragm can be further thinned, and a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity can be obtained.

According to the third aspect of the present invention, since the rounded portion is provided at the edge of the gap chamber, the stress generated at the edge of the gap chamber is concentrated even when a large pressure is applied to the gap chamber. There is no part. Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

According to the fourth aspect of the present invention, the diaphragm is formed only of a silicon single crystal material. That is,
A diaphragm having no residual strain can be formed, the diaphragm can be further thinned, and a semiconductor pressure measuring device with further improved measurement accuracy and sensitivity can be obtained.

Further, since the rounded portion is provided at the edge of the gap chamber, there is no portion where the stress generated at the edge of the gap chamber is concentrated even when a large pressure is applied to the gap chamber. Therefore, the breaking pressure can be increased. As a result, a semiconductor pressure measuring device with a high withstand voltage can be obtained.

According to claim 5 of the present invention, since the diaphragm is formed by at least one of the polysilicon layer, the silicon oxide film layer, and the second single crystal silicon substrate,
The semiconductor pressure measuring device can be selectively used depending on the application of the semiconductor pressure measuring device, and a semiconductor pressure measuring device having a high degree of freedom for the application is obtained.

According to the sixth aspect of the present invention, (1) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other, the thermal silicon oxide film layer absorbs excess water. Therefore, a method of manufacturing a semiconductor pressure measuring device in which voids are unlikely to be generated can be obtained.

(2) Since the polysilicon layer and the silicon oxide film layer are brought into contact with each other, the temperature is set at 1100 ° C.
In the above, since the silicon oxide film layer is softened, there is an effect of deforming and filling even if a void exists.

Further, a method for manufacturing a semiconductor pressure measuring device capable of taking in particles such as dust and eliminating voids is obtained. (3) As shown in step (h), the second silicon oxide film forming the void chamber is in a state of being embedded in the first silicon single crystal substrate.

In such a state, even if the thickness of the second silicon oxide film forming the void space increases, the thickness of the first silicon oxide film and the thickness of the second silicon oxide film can be optimized. For example, the step between the second silicon oxide film and the first silicon single crystal substrate in the step (h) is specifically, for example,
It can be controlled to a step of 0.1 μm or less.

That is, even when the thickness of the second silicon oxide film forming the void chamber is increased to, for example, 1 μm or more, the step can be controlled to 0.1 μm or less. That is,
Since the gap in the gap chamber can be enlarged, even if fine foreign matter enters and adheres to the gap chamber, it can be used and a high yield can be obtained. Therefore, a method for manufacturing an inexpensive semiconductor pressure measuring device having stable characteristics can be obtained.

(4) Since the step can be reduced, the polysilicon layer for flattening can be thinned. For this reason, the polysilicon growth temperature of the polysilicon layer can be lowered, and the gray size can be reduced, so that the polishing process is facilitated. In addition, since the amount of polishing can be reduced, grinding is not required.

Further, since the variation in the thickness of the polysilicon layer within the wafer or between the wafers is reduced, the polishing operation is easy and simple, and a method of manufacturing an inexpensive semiconductor pressure measuring device can be obtained.

Therefore, according to the present invention, it is possible to realize a semiconductor pressure measuring device and a manufacturing method thereof which are inexpensive, have good accuracy, sensitivity, and large pressure characteristics, have a stable manufacturing process, and have little fluctuation in characteristics. I can do it.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an explanatory view of a manufacturing process of FIG. 1;

FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 4 is an explanatory view of a main part configuration of another embodiment of the present invention.

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 6 is an explanatory diagram of a configuration of a conventional example generally used in the related art.

FIG. 7 is an explanatory view of a manufacturing process of FIG. 6;

DESCRIPTION OF SYMBOLS 11 First single-crystal silicon substrate 12 Polysilicon layer 13 Silicon oxide film layer 14 Second single-crystal silicon substrate 15 Diaphragm 16 Recess 17 Void chamber 18 Strain detecting element 19 Pressure guiding hole 21 First single Crystal silicon substrate 22 Polysilicon layer 23 Silicon oxide film layer 24 Second single crystal silicon substrate 25 Concave portion 26 Diaphragm 27 Void chamber 28 Strain detection sensor 29 Pressure guiding hole 31 First single crystal silicon substrate 32 Polysilicon layer 33 Silicon oxide Film layer 34 second single-crystal silicon substrate 35 diaphragm 36 concave portion 361 rounded portion 362 bottom surface 363 side surface 37 void space 38 strain detecting element 39 pressure-guiding hole 41 first single-crystal silicon substrate 42 polysilicon layer 43 silicon oxide film layer 44 Second single crystal silicon substrate 45 Concave part 451 Round part 452 bottom surface 453 side surface 46 diaphragm 47 void space 48 strain detection sensor 49 pressure guiding hole 201 first single crystal silicon substrate 202 first silicon nitride film 203 predetermined location 204 first silicon oxide film 205 second silicon nitride film 206 Second silicon oxide film 207 Polysilicon layer 208 Second single crystal silicon substrate 209 Third silicon oxide film 211 Strain detection sensor 212 Hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA40 BB20 CC02 DD05 EE13 FF11 FF23 FF43 GG01 GG14 HH05

Claims (6)

[Claims] 1. A semiconductor pressure measuring device in which a void chamber is provided on one surface side of a diaphragm and a measurement pressure is applied to the other surface side of the diaphragm, wherein: a first single-crystal silicon substrate; A polysilicon layer formed by a semiconductor process with one surface in contact with one surface of the substrate; a silicon oxide film layer formed by a semiconductor process with one surface in contact with the other surface of the polysilicon layer; A second single-crystal silicon substrate provided in contact with one surface to form a diaphragm together with the polysilicon layer and the silicon oxide film layer; and a gap between the polysilicon layer provided on one surface of the first single-crystal silicon substrate. A concave portion forming a chamber; a strain detection sensor provided on the diaphragm; and the other surface of the first single crystal silicon substrate or the second surface.
A pressure-guiding hole communicating from the other surface of the single-crystal silicon substrate to the cavity and communicating the cavity with the outside. 2. A semiconductor pressure measuring device in which a void chamber is provided on one surface side of a diaphragm and a measurement pressure is applied to the other surface side of the diaphragm, wherein: a first single crystal silicon substrate; A polysilicon layer formed by a semiconductor conductor process with one surface in contact with one surface of the substrate; a silicon oxide film layer formed by a semiconductor conductor process with one surface in contact with the other surface of the polysilicon layer; A second single-crystal silicon substrate provided with one surface in contact with a surface; and a diaphragm provided on one surface of the first single-crystal silicon substrate and forming a diaphragm on the first single-crystal silicon substrate. A concave portion forming a void chamber; a strain detection sensor provided on the diaphragm; and the other surface of the first single crystal silicon substrate or the second surface.
A pressure-guiding hole communicating from the other surface of the single-crystal silicon substrate to the cavity and communicating the cavity with the outside. 3. A semiconductor pressure measuring device in which a void space is provided on one surface side of a diaphragm and a measurement pressure is applied to the other surface side of the diaphragm, wherein: a first single crystal silicon substrate; A polysilicon layer formed by a semiconductor conductor process with one surface in contact with one surface of the substrate; a silicon oxide film layer formed by a semiconductor conductor process with one surface in contact with the other surface of the polysilicon layer; A second single-crystal silicon substrate provided in contact with one surface to form a diaphragm together with the polysilicon layer and the silicon oxide film layer; and a polysilicon layer provided on one surface side of the first single-crystal silicon substrate. A concave portion forming a void chamber; a round portion provided at a portion where the bottom surface and the side surface of the concave portion are in contact; and a strain detection provided at the diaphragm. A sensor, and the other surface of the first single crystal silicon substrate or the second surface.
A pressure-guiding hole communicating from the other surface of the single-crystal silicon substrate to the cavity and communicating the cavity with the outside. 4. A semiconductor pressure measuring device in which a void space is provided on one surface side of a diaphragm and a measurement pressure is applied to the other surface side of the diaphragm, wherein: a first single crystal silicon substrate; A polysilicon layer formed by a semiconductor conductor process with one surface in contact with one surface of the substrate; a silicon oxide film layer formed by a semiconductor conductor process with one surface in contact with the other surface of the polysilicon layer; A second single-crystal silicon substrate provided with one surface in contact with a surface; and a diaphragm provided on one surface of the first single-crystal silicon substrate and forming a diaphragm on the first single-crystal silicon substrate. A concave portion forming a void chamber; a round portion provided at a portion where a bottom surface and a side surface of the concave portion are in contact; a strain detection sensor provided at the diaphragm; Other surface or the second single-crystal silicon substrate
A pressure-guiding hole communicating from the other surface of the single-crystal silicon substrate to the cavity and communicating the cavity with the outside. 5. The semiconductor device according to claim 1, wherein said diaphragm is formed by at least one of said polysilicon layer, said silicon oxide film layer, and said second single-crystal silicon substrate. Semiconductor pressure measuring device. 6. A method of manufacturing a semiconductor pressure measuring device in which a cavity is provided on one surface side of a diaphragm and a measurement pressure is applied to the other surface side of the diaphragm, comprising the following steps: Device manufacturing method. (A) forming a first silicon nitride film on the surface of the first single-crystal silicon substrate; (B) removing a required portion of the first silicon nitride film on the first single crystal silicon substrate by photolithography; (C) a step of oxidizing the first single crystal silicon substrate to form a first silicon oxide film. (D) removing the first silicon oxide film. (E) forming a second silicon nitride film on the surface of the first single viscous silicon substrate and the surface of the first silicon nitride film where the first silicon oxide film has been removed; (F) removing the second silicon nitride film by anisotropic etching. (G) forming a second silicon oxide film by oxidizing the first single crystal silicon substrate at the location where the second silicon nitride film has been removed; (H) removing the first silicon nitride film and the second silicon nitride film formed on the first single crystal silicon substrate. (I) forming a polysilicon layer on one surface of the first single crystal silicon substrate; (J) a step of flattening the surface of the polysilicon layer by polishing; (K) forming a third silicon oxide film on one surface of the second single crystal silicon substrate; (L) a step of bonding a polysilicon layer surface of the first single crystal silicon substrate to a third silicon oxide film of the second single crystal silicon substrate. (M) a step of polishing the first or second single-crystal silicon substrate while keeping the thickness of the diaphragm. (N) forming a strain detection sensor on the diaphragm; (O) forming a hole in the first or second single-crystal silicon substrate to reach the second silicon oxide film; (P) removing the second silicon oxide film by selective etching from a hole reaching the second silicon oxide film.