JP2002350259A - Semiconductor pressure senor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor and a manufacturing method for it capable of improving detection accuracy and temperature characteristics of the detection precision. SOLUTION: This semiconductor is provided with a SOI base board 1, in which a buried oxide film 3 formed of a silicon oxide film is formed in the middle of the thickness direction and a silicon active layer 2 is formed on the main surface side, a diaphragm part 6 formed by etching a supporting base board 4 from the back face of the SOI base board 1 and forming a pressure introduction port 4a reaching the buried oxide film 3, and a gauge resistor 5 formed on the main surface side of the active layer 2 for detecting deformation of the diaphragm part 6. The buried oxide film 3 is arranged over the whole surface on the back side of the active layer 2.

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a semiconductor pressure sensor of this type, as shown in FIG. 5C, a buried oxide film (buried insulating layer) 3 made of a silicon oxide film is formed in the middle of the thickness direction. A pressure sensor chip A using an SOI substrate 1 in which an active layer 2 made of silicon is formed on the main surface side has been conventionally provided (for example, Japanese Patent Laid-Open No. 9-1).
No. 13390).

The SOI substrate 1 has a three-layer structure of a support substrate (support layer) 4 made of silicon, a buried oxide film 3, and an active layer 2. In this semiconductor pressure sensor, the SOI
The substrate 1 is etched from the back side to provide a pressure introducing port 4a formed of a concave portion, whereby the thin diaphragm portion 6 is formed.
And a gauge resistor 5 for detecting deformation of the diaphragm 6 is formed on the main surface side in the active layer 2. A surface oxide film 7 made of a silicon oxide film is formed on active layer 2, and a surface nitride film 8 made of a silicon nitride film is formed on surface oxide film 7. still,
The portion of the buried oxide film 3 exposed from the pressure introducing port 4a is removed, and a region where the buried oxide film 3 exists and a region where the buried oxide film 3 does not exist are provided in the chip.

Here, a method of manufacturing the semiconductor pressure sensor will be described with reference to FIGS.

First, ion implantation (impurity implantation) is performed on the main surface side of the SOI substrate 1 to form a gauge resistor 5 by diffusing the implanted impurities. A surface oxide film 7 made of a silicon oxide film and a back surface oxide film 9 on the main surface side and the back side
Is formed, and a surface nitride film 8 made of a silicon nitride film is formed on the surface oxide film 7. Then, after applying and forming a photoresist layer (not shown) on the back surface oxide film 9 on the back surface side of the SOI substrate 1, the photoresist layer is patterned by a photolithography technique to form a pressure inlet 4a, By using the patterned photoresist layer (hereinafter, referred to as a photoresist mask) as a mask, an opening window 9a is formed in the back oxide film 9, and then the photoresist mask is removed, as shown in FIG.
The structure shown in (a) is obtained.

Next, the support substrate 4 of the SOI substrate 1 is anisotropically etched (primary etching) from the back surface side using the back surface oxide film 9 having the opening windows 9a as a mask, to reach the buried oxide film 3. By forming the pressure inlet 4a, the structure shown in FIG. 5B is obtained.

Thereafter, secondary etching is performed from the back side of the SOI substrate 1 to form a back oxide film 9 formed on the back side of the support substrate 4 and a portion of the buried oxide film 3 exposed from the pressure inlet 4a. Is removed to form the diaphragm portion 6, and the structure shown in FIG. 5C is obtained.

[0008]

In the semiconductor pressure sensor having the above-described structure, the support substrate 4 is anodically bonded to a glass pedestal (not shown) having a thermal expansion coefficient close to that of silicon. Is removed by etching, but in the step of removing the back oxide film 9, the portion of the buried oxide film 3 exposed from the pressure inlet 4a is also removed at the same time.

Therefore, the pressure sensor chip A has a region where the buried oxide film 3 exists and a region where the buried oxide film 3 does not exist, and the distribution of the residual stress and the thermal stress varies, so that the accuracy of pressure detection decreases. However, there is a problem that the temperature characteristics of the detection accuracy are particularly deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a semiconductor pressure sensor having improved detection accuracy and improved temperature characteristics of detection accuracy, and a method of manufacturing the same. Is to do.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a semiconductor substrate having a buried insulating layer formed in the middle in a thickness direction and an active layer formed on a main surface side; A diaphragm portion formed by providing a pressure introduction port reaching the buried insulating layer from the back surface of the semiconductor substrate, and a gauge resistor formed on the main surface side in the active layer and detecting deformation of the diaphragm portion, comprising: The insulating layer is provided over the entire back surface of the active layer, and the buried insulating layer is provided over the entire back surface of the active layer. Unlike the case where there is no region, the distribution of the residual stress and the thermal stress does not become non-uniform, so that the pressure detection accuracy is improved and the temperature characteristics of the detection accuracy can be further improved.

According to a second aspect of the present invention, there is provided a semiconductor device in which a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate,
After forming a back surface insulating film on the back surface side of the support layer and providing an opening window for forming a pressure inlet in the back surface insulating film, using an etching solution that etches only the support layer using the back surface insulating film as a mask. After performing primary etching from the back side and removing a portion of the support layer exposed from the opening window by a dimension slightly smaller than the thickness dimension of the support layer in the thickness direction, the etching selectivity is set to the thickness of the support layer remaining in the primary etching. And the thickness of the backside insulating film is adjusted to perform a secondary etching, and the portion of the support layer and the backside insulating film remaining in the primary etching are simultaneously removed to provide a pressure introduction port reaching the buried insulating layer. The diaphragm portion is formed by doing so, a part of the support layer is left when performing the primary etching to form the pressure introduction port, and the portion of the support layer and the back surface left by the primary etching Since the pressure introduction port that reaches the buried insulating layer is formed by simultaneously removing the edge film and the secondary film by the secondary etching, the buried insulating layer can be formed over the entire back surface of the active layer. A semiconductor pressure sensor having high pressure detection accuracy and improved temperature characteristics of detection accuracy can be provided.

According to a third aspect of the present invention, there is provided a semiconductor device in which a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate,
After forming a back surface insulating film on the back surface side of the support layer and providing an opening window for forming a pressure inlet in the back surface insulating film, using this back surface insulating film as a mask, the etching selectivity is determined by the thickness of the support layer and the back surface. Perform etching by adjusting the ratio to the insulating film, and simultaneously remove the portion of the support layer exposed from the opening window and the back surface insulating film, and form a diaphragm part by providing a pressure introduction port that reaches the buried insulating layer When the etching is performed to form the pressure inlet, the portion of the support layer exposed from the opening window and the back surface insulating film are simultaneously removed to form the pressure inlet which reaches the buried insulating layer. Therefore, a buried insulating layer can be formed over the entire back surface of the active layer, and a semiconductor pressure sensor with high pressure detection accuracy and improved temperature characteristics of detection accuracy can be provided. it can.

According to a fourth aspect of the present invention, there is provided a semiconductor device wherein a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate,
A backside insulating film is formed on the backside of the support layer, and the backside insulating film is etched from the backside to form a film having a desired thickness, and then an opening for forming a pressure inlet in the backside insulating film. A window is provided, and using the back surface insulating film as a mask, etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer to the ratio of the back surface insulating film, and the portion of the support layer exposed from the opening window and the back surface insulating film At the same time, the diaphragm portion is formed by providing a pressure introduction port reaching the buried insulating layer, and a portion of the support layer exposed from the opening window when the pressure introduction port is formed by etching. And the backside insulating film are removed at the same time to form a pressure introduction port reaching the buried insulating layer, so that the buried insulating layer can be formed over the entire backside of the active layer, and the pressure can be reduced. High detection accuracy and high detection accuracy It is possible to provide a semiconductor pressure sensor with improved degrees properties.

According to a fifth aspect of the present invention, there is provided a semiconductor device in which a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate,
After a backside insulating film having a desired thickness is formed on the backside of the support layer, an opening window for forming a pressure inlet is provided in the backside insulating film, and the backside insulating film is used as a mask to support an etching selectivity. Adjusting the thickness of the layer and the ratio of the back surface insulating film to perform etching, simultaneously removing the portion of the support layer exposed from the opening window and the back surface insulating film, and providing a pressure introduction port reaching the buried insulating layer. When etching is performed to form the pressure inlet, the portion of the support layer exposed from the opening window and the back surface insulating film are simultaneously removed to reach the buried insulating layer. Since the pressure inlet is formed, the buried insulating layer can be formed over the entire back surface of the active layer, and the pressure detection accuracy is high.
In addition, a semiconductor pressure sensor having improved temperature characteristics of detection accuracy can be provided.

[0016]

Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention.
This will be described with reference to (a) to (c). In the semiconductor pressure sensor according to the present embodiment, as shown in FIG. 1C, a buried oxide film (buried insulating layer) 3 made of a silicon oxide film is formed in the middle in the thickness direction, and is formed on the main surface side. It has a pressure sensor chip A using an SOI substrate 1 on which an active layer 2 made of silicon is formed.

The SOI substrate 1 has a three-layer structure of a support substrate (support layer) 4 made of silicon, a buried oxide film 3, and an active layer 2. In this semiconductor pressure sensor, the SOI
The substrate 1 is etched from the back side to provide a pressure introducing port 4a formed of a concave portion, whereby the thin diaphragm portion 6 is formed.
A gauge resistor 5 for detecting deformation of the diaphragm 6 is formed on the main surface side in the active layer 2. A surface oxide film 7 made of a silicon oxide film is formed on active layer 2, and a surface nitride film 8 made of a silicon nitride film is formed on surface oxide film 7.

Here, since the buried oxide film 3 is provided on the entire back surface of the active layer 2, there is a case where a region with the buried oxide film 3 and a region without the buried oxide film 3 exist in the chip. In addition, the distribution of the residual stress and the thermal stress does not become uneven, and the accuracy of detecting the pressure is improved. Further, since the stress strain generated in the chip is reduced, the support substrate 4 can be anodic-bonded to the glass pedestal (not shown) in a state where the stress strain is reduced, and the temperature characteristics of detection accuracy can be improved. it can.

Hereinafter, a method of manufacturing the semiconductor pressure sensor will be described with reference to FIGS. 1 (a) to 1 (c).

First, ion implantation (impurity implantation) is performed on the main surface side of the SOI substrate 1, and the implanted impurity is diffused to form a gauge resistor 5. Then, the SOI substrate 1 is subjected to a thermal oxidation process, thereby A surface oxide film 7 made of a silicon oxide film and a back surface oxide film 9 on the main surface side and the back side
Is formed, and a surface nitride film 8 made of a silicon nitride film is formed on the surface oxide film 7. Then, after applying and forming a photoresist layer (not shown) on the back surface oxide film 9 on the back surface side of the SOI substrate 1, the photoresist layer is patterned by a photolithography technique to form a pressure inlet 4a, An opening window 9a is formed in the back oxide film 9 using the patterned photoresist layer as a mask, and then the photoresist mask is removed to obtain the structure shown in FIG.

Next, the support substrate 4 of the SOI substrate 1 is subjected to anisotropic etching (primary etching) from the back surface side using the back surface oxide film 9 having the opening windows 9a as a mask. The etching conditions at this time are adjusted so that the etching selectivity between Si and SiO ₂ is sufficiently large, and the portion of the support substrate 4 exposed from the opening window 9a is etched to form the pressure introducing port 4a. For example, an 11% solution of TMAH is used as an etching solution, and the liquid temperature is set to about 95 ° C.
The amount of etching of the support substrate 4 in the thickness direction is set to be slightly smaller than the thickness of the support substrate 4 (for example, about 300 μm) by adjusting the etching time. The primary etching is completed while leaving a part of the layer of the support substrate 4 (for example, about 10 μm) to obtain a structure as shown in FIG.

Thereafter, the support substrate 4 of the SOI substrate 1 is subjected to anisotropic etching (secondary etching) from the back side. The etching conditions at this time include the etching selectivity between Si and SiO ₂ , the ratio between the thickness of the support substrate 4 (Si) remaining above the pressure inlet 4 a and the thickness of the back oxide film 9 (SiO ₂ ). Adjust to match. For example, when the thickness of the support substrate 4 remaining above the pressure inlet 4a is about 10 μm and the thickness of the back oxide film 9 is about 1 μm, Si and SiO
A 40% solution of KOH is used as an etching solution and the liquid temperature is set to about 115 ° C. so that the etching selectivity with ₂ is 10: 1. By performing the secondary etching under such etching conditions, a part of the support substrate 4 remaining above the pressure inlet 4a and the back surface oxide film 9 are simultaneously removed, and the diaphragm 6 is formed. The structure as shown in (c) is obtained.

According to the above-described manufacturing method, after the etching is completed in a state where the layer of the support substrate 4 is slightly left above the pressure introducing port 4a by the primary etching, the etching is finished above the pressure introducing port 4a by the secondary etching. Since the remaining layer of the support substrate 4 and the backside oxide film 9 are removed at the same time, the buried oxide film 3 can be left over the entire backside of the active layer 2 of the SOI substrate 1, and the conventional semiconductor Unlike the pressure sensor, there is no region where the buried oxide film 3 exists and the region where the buried oxide film 3 does not exist, so that unevenness in the distribution of the residual stress and the thermal stress in the pressure sensor chip A can be reduced.

(Embodiment 2) Embodiment 2 of the present invention is shown in FIG.
Description will be made with reference to (a) and (b). Since the semiconductor pressure sensor of the present embodiment has the same structure as that of the semiconductor pressure sensor of the first embodiment as shown in FIG. 2B, the same components are denoted by the same reference numerals. Description is omitted.

Here, a method of manufacturing the semiconductor pressure sensor will be described with reference to FIGS.

First, ion implantation (impurity implantation) is performed on the main surface side of the SOI substrate 1, and the implanted impurity is diffused to form a gauge resistor 5. Then, the SOI substrate 1 is subjected to a thermal oxidation process, thereby A surface oxide film 7 made of a silicon oxide film and a back surface oxide film 9 on the main surface side and the back side
Is formed, and a surface nitride film 8 made of a silicon nitride film is formed on the surface oxide film 7. Then, after applying and forming a photoresist layer (not shown) on the back surface oxide film 9 on the back surface side of the SOI substrate 1, the photoresist layer is patterned by a photolithography technique to form a pressure inlet 4a, An opening window 9a is formed in the back surface oxide film 9 using the patterned photoresist layer as a mask, and then the photoresist mask is removed to obtain a structure shown in FIG.

Thereafter, the support substrate 4 of the SOI substrate 1 is anisotropically etched from the back surface side, using the back surface oxide film 9 on which the opening windows 9a are formed as a mask. As etching conditions at this time, the etching selectivity between Si and SiO ₂ is as follows.
Support substrate 4 (Si) thickness and back oxide film 9 (SiO ₂ )
For example, when the thickness of the support substrate 4 is about 300 μm and the thickness of the back oxide film 9 is about 1 μm, the etching selectivity between Si and SiO ₂ is set to 300: 1. As an etching solution, K
Using a 32% solution of OH, the liquid temperature is set to 75 ° C. By anisotropically etching the support substrate 4 of the SOI substrate 1 from the back side under such etching conditions, the portion of the support substrate 4 exposed from the opening window 9a and the back surface oxide film 9 are simultaneously removed, and the buried oxide film is removed. A pressure inlet 4a reaching the membrane 3 is formed, and a structure as shown in FIG. 2B is obtained.

According to the above-mentioned manufacturing method, by adjusting the etching conditions, the portion of the support substrate 4 exposed from the opening window 9a formed in the back oxide film 9 and the back oxide film 9 are simultaneously removed, and Pressure inlet 4a reaching the oxide film 3
Is formed, the buried oxide film 3 can be left over the entire back surface of the active layer 2 of the SOI substrate 1, and a region where the buried oxide film 3 is present as in the conventional semiconductor pressure sensor. There is no such region, and unevenness in the distribution of residual stress and thermal stress in the pressure sensor chip A can be reduced.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention.
This will be described with reference to (a) to (c). Since the semiconductor pressure sensor of the present embodiment has the same structure as that of the semiconductor pressure sensor of the first embodiment as shown in FIG. 3C, the same components are denoted by the same reference numerals. Description is omitted.

Here, a method of manufacturing the semiconductor pressure sensor will be described with reference to FIGS.

First, ion implantation (impurity implantation) is performed on the main surface side of the SOI substrate 1, and the implanted impurity is diffused to form a gauge resistor 5. Then, the SOI substrate 1 is subjected to a thermal oxidation process, thereby A surface oxide film 7 made of a silicon oxide film and a back surface oxide film 9 on the main surface side and the back side
Is formed, and a surface nitride film 8 made of a silicon nitride film is formed on the surface oxide film 7. Then, etching is performed from the back side of the SOI substrate 1 to form the back oxide film 9.
The thickness shown in FIG. 3A is obtained by setting the thickness of the thin film to about 1/10 to 1/100 of the thickness before etching. In the present embodiment, for example, a back oxide film 9 having a thickness of about 1 μm is formed on the back surface side of the support substrate 4, and the back oxide film 9 is formed.
Is etched to a thickness of about 300 °.

Next, after a photoresist layer (not shown) is applied and formed on the back oxide film 9 on the back side of the SOI substrate 1, the photoresist layer is formed by photolithography to form the pressure inlet 4a. Patterned by
An opening window 9a is formed in the back oxide film 9 using the patterned photoresist layer as a mask, and then the photoresist mask is removed to obtain a structure as shown in FIG.

Thereafter, the supporting substrate 4 of the SOI substrate 1 is anisotropically etched from the back surface side using the back surface oxide film 9 having the opening windows 9a as a mask. As etching conditions at this time, the etching selectivity between Si and SiO ₂ is as follows.
Support substrate 4 (Si) thickness and back oxide film 9 (SiO ₂ )
For example, when the thickness of the support substrate 4 is about 300 μm and the thickness of the back oxide film 9 is about 300 °, the etching selectivity between Si and SiO ₂ is 10,000: 1. As an etching solution, an 11% solution of TMAH is used, and the liquid temperature is set to 95 ° C. By anisotropically etching the support substrate 4 of the SOI substrate 1 from the back surface under such etching conditions, the portion of the support substrate 4 exposed from the opening window 9a and the back oxide film 9
Are simultaneously removed, and a pressure introduction port 4a reaching the buried oxide film 3 is formed, whereby a structure as shown in FIG. 3C is obtained.

According to the above-described manufacturing method, after the back oxide film 9 is etched to a desired film thickness, an opening window 9a is formed in the back oxide film 9 using photolithography technology.
Further, by performing anisotropic etching using the back surface oxide film 9 as a mask, the portion of the support substrate 4 exposed from the opening window 9a and the back surface oxide film 9 are simultaneously removed, and the buried oxide film 3 is removed.
Is formed, the buried oxide film 3 can be left on the entire back surface of the active layer 2 of the SOI substrate 1 and the buried oxide film 3 can be buried as in a conventional semiconductor pressure sensor. There is no region where the film 3 exists and there is no region, and it is possible to reduce unevenness in the distribution of the residual stress and the thermal stress in the pressure sensor chip A.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention.
This will be described with reference to (a) to (d). The semiconductor pressure sensor according to the present embodiment has the same structure as the semiconductor pressure sensor according to the first embodiment as shown in FIG. 4D. Description is omitted.

Here, a method of manufacturing the semiconductor pressure sensor will be described with reference to FIGS.

First, ion implantation (impurity implantation) is performed on the main surface side of the SOI substrate 1 and the implanted impurity is diffused to form a gauge resistor 5. A surface oxide film 7 made of a silicon oxide film is formed on the main surface side of the substrate 1, and a surface nitride film 8 made of a silicon nitride film is formed on the surface oxide film 7. At this time, a back surface oxide film (not shown) made of a silicon oxide film is also formed on the back surface side of the SOI substrate 1, and the back surface oxide film is removed by etching to obtain a structure shown in FIG.
A structure as shown in FIG.

Next, on the back surface of the SOI substrate 1, a back oxide film 9 made of a silicon oxide film having a thickness of about 1/10 to 1/100 of the thickness of the back oxide film removed in the previous step is formed. Thus, a structure as shown in FIG. In the present embodiment, the back oxide film 9 having a thickness of, for example, about 300 ° is formed.

After a photoresist layer (not shown) is applied on the back oxide film 9 on the back side of the SOI substrate 1, the photoresist layer is formed by photolithography in order to form a pressure inlet 4a. Patterning,
An opening window 9a is formed in the back oxide film 9 using the patterned photoresist layer as a mask, and then the photoresist mask is removed to obtain a structure shown in FIG.

Thereafter, the support substrate 4 of the SOI substrate 1 is anisotropically etched from the back surface side using the back surface oxide film 9 having the opening windows 9a as a mask. As etching conditions at this time, the etching selectivity between Si and SiO ₂ is as follows.
Support substrate 4 (Si) thickness and back oxide film 9 (SiO ₂ )
For example, when the thickness of the support substrate 4 is about 300 μm and the thickness of the back oxide film 9 is about 300 °, the etching selectivity between Si and SiO ₂ is 10,000: 1. A 32% solution of KOH is used as an etching solution, and the solution temperature is set to 75 ° C.
Under such etching conditions, the supporting substrate 4 of the SOI substrate 1
Is anisotropically etched from the back side, whereby the portion of the support substrate 4 exposed from the opening window 9a and the back surface oxide film 9 are simultaneously removed, and the pressure introducing port 4a reaching the buried oxide film 3 is removed.
Is formed, and a structure as shown in FIG. 4D is obtained.

According to the above-described manufacturing method, after the back oxide film 9 having a desired thickness is formed on the back surface of the SOI substrate 1, the opening window 9 is formed in the back oxide film 9 by using the photolithography technique.
a, and anisotropic etching is performed using the back surface oxide film 9 as a mask, thereby simultaneously removing the portion of the support substrate 4 exposed from the opening window 9a and the back surface oxide film 9,
Since the pressure introduction port 4a reaching the buried oxide film 3 is formed, the buried oxide film 3 can be left over the entire back surface of the active layer 2 of the SOI substrate 1, and the conventional semiconductor pressure sensor has As described above, there is no region where the buried oxide film 3 exists and the region where the buried oxide film 3 does not exist, and it is possible to reduce unevenness in the distribution of the residual stress and the thermal stress in the pressure sensor chip A.

In the above embodiments, the thickness of the support substrate 4 and the thickness of the back oxide film 9 are illustrated for ease of explanation. However, the present invention is not intended to be limited to the above dimensions. What is necessary is just to set the thickness dimension of each part suitably so that may be satisfied.

[0044]

As described above, according to the first aspect of the present invention, a semiconductor substrate in which a buried insulating layer is formed in the middle in the thickness direction and an active layer is formed on the main surface side, and the buried insulating layer is formed from the back surface of the semiconductor substrate. A diaphragm portion formed by providing a pressure introduction port reaching the insulating layer, and a gauge resistor formed on the main surface side in the active layer and detecting deformation of the diaphragm portion, wherein the embedded insulating layer is a back surface of the active layer. Characterized in that the buried insulating layer is provided over the entire back surface of the active layer, so that there is a region where the buried insulating layer exists and a region where the buried insulating layer does not exist. As described above, since the distribution of the residual stress and the thermal stress does not become uneven, the pressure detection accuracy is improved, and the temperature characteristics of the detection accuracy can be further improved.

According to a second aspect of the present invention, there is provided a semiconductor device wherein a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate, wherein a back surface insulating film is formed on the back surface side of a support layer, and an opening window for forming a pressure inlet is provided in the back surface insulating film. Performing primary etching from the back side using an etching solution that etches only the support layer as a mask, after removing the portion of the support layer exposed from the opening window by a dimension slightly smaller than the thickness of the support layer in the thickness direction, Secondary etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer remaining in the primary etching to the thickness of the back surface insulating film, and simultaneously removing the portion of the support layer remaining in the primary etching and the back surface insulating film. The diaphragm portion is formed by providing a pressure introduction port reaching the buried insulating layer, and a part of the support layer is left when the pressure introduction port is formed by performing the primary etching, and the primary etching is left. The part of the support layer and the backside insulating film that have been removed are simultaneously removed by secondary etching to form a pressure introduction port that reaches the buried insulating layer, so that the buried insulating layer is entirely covered on the backside of the active layer. The semiconductor pressure sensor having a high pressure detection accuracy and improved temperature characteristics of the detection accuracy can be provided.

According to a third aspect of the present invention, there is provided a semiconductor device wherein a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate, wherein a back surface insulating film is formed on the back surface side of a support layer, and an opening window for forming a pressure inlet is provided in the back surface insulating film. Using the mask as a mask, etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer to the ratio of the back surface insulating film, and simultaneously removing the portion of the support layer exposed from the opening window and the back surface insulating film to form a buried insulating layer. The diaphragm portion is formed by providing a pressure introduction port that reaches, and when the pressure introduction port is formed by performing etching, the portion of the support layer exposed from the opening window and the back surface insulating film are simultaneously removed. hand,
Since the pressure introduction port reaching the buried insulating layer is formed, the buried insulating layer can be formed over the entire back surface of the active layer, so that the pressure detection accuracy is high and the temperature characteristics of the detection accuracy are high. There is an effect that it is possible to provide a semiconductor pressure sensor in which is improved.

According to a fourth aspect of the present invention, there is provided a semiconductor device wherein a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate, wherein a back surface insulating film is formed on the back surface side of the support layer, and the back surface insulating film is etched from the back surface side to form the film to a desired thickness. An opening window for forming a pressure inlet is provided in the back insulating film, and the etching is performed by using the back insulating film as a mask and adjusting an etching selectivity to a ratio between the thickness of the support layer and the back insulating film. The diaphragm portion was formed by simultaneously removing the portion of the support layer exposed from the substrate and the back surface insulating film and providing a pressure introduction port reaching the buried insulating layer, and forming the pressure introduction port by performing etching When you open windows Since the exposed portions of the support layer and the back surface insulating film are removed at the same time to form the pressure introduction port reaching the buried insulating layer, the buried insulating layer is formed over the entire back surface of the active layer. Can have high pressure detection accuracy,
In addition, there is an effect that a semiconductor pressure sensor having improved temperature characteristics of detection accuracy can be provided.

According to a fifth aspect of the present invention, there is provided a semiconductor device wherein a buried insulating layer is formed in the middle of the thickness direction, a support layer is formed on the back side of the buried insulating layer, and an active layer is formed on the main surface side. A method of manufacturing a semiconductor pressure sensor using a substrate, after forming a back surface insulating film having a desired thickness on the back surface side of the support layer, providing an opening window for forming a pressure inlet in the back surface insulating film, Using this back surface insulating film as a mask, etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer to the ratio of the back surface insulating film, and simultaneously removing the portion of the support layer exposed from the opening window and the back surface insulating film. The diaphragm portion is formed by providing a pressure introduction port reaching the buried insulating layer. When the etching is performed to form the pressure introduction port, the portion of the support layer exposed from the opening window and the back surface insulating film And remove at the same time Since the pressure introduction port reaching the buried insulating layer is formed, the buried insulating layer can be formed over the entire back surface of the active layer, so that the pressure detection accuracy is high and the temperature characteristics of the detection accuracy are high. There is an effect that it is possible to provide a semiconductor pressure sensor in which is improved.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views illustrating respective manufacturing steps of a semiconductor pressure sensor according to a first embodiment.

FIGS. 2A and 2B are cross-sectional views illustrating respective manufacturing steps of a semiconductor pressure sensor according to a second embodiment.

FIGS. 3A to 3C are cross-sectional views illustrating respective manufacturing steps of a semiconductor pressure sensor according to a third embodiment.

FIGS. 4A to 4D are cross-sectional views illustrating respective manufacturing steps of a semiconductor pressure sensor according to a fourth embodiment.

5 (a) to 5 (c) are cross-sectional views illustrating respective manufacturing steps of a conventional semiconductor pressure sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 SOI substrate 2 active layer 3 buried oxide film 4 support substrate 4 a pressure inlet 5 gauge resistor 6 diaphragm

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisamiya Miyajima 1048 Odakadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. F term (reference) 2F055 AA40 BB00 BB20 CC02 DD05 EE13 FF01 FF11 GG11 4M112 AA01 CA03 CA05 CA08 DA04 DA10 DA11 EA03 EA06 EA07 FA01

Claims (5)

[Claims] 1. A semiconductor substrate having a buried insulating layer formed in the middle of a thickness direction and an active layer formed on a main surface side, and a pressure introducing port reaching the buried insulating layer from the back surface of the semiconductor substrate. A diaphragm formed, and a gauge resistor formed on the main surface side of the active layer and detecting deformation of the diaphragm is provided, and the embedded insulating layer is provided on the entire back surface of the active layer. A semiconductor pressure sensor. 2. A buried insulating layer is formed in the middle of a thickness direction.
A method of manufacturing a semiconductor pressure sensor using a semiconductor substrate having a support layer formed on the back surface side of the buried insulating layer and an active layer formed on the main surface side, comprising: forming a back surface insulating film on the back surface side of the support layer. After forming an opening window for forming a pressure introduction port in the back surface insulating film, primary etching is performed from the back surface side using an etching solution for etching only the support layer using the back surface insulating film as a mask, and the opening window is formed. After removing the portion of the support layer exposed from the substrate by a dimension slightly smaller than the thickness of the support layer in the thickness direction, the etching selectivity is reduced to the ratio of the thickness of the support layer remaining in the primary etching to the thickness of the back surface insulating film. Adjusting and performing secondary etching, simultaneously removing the portion of the support layer and the back surface insulating film remaining in the primary etching, and providing a pressure inlet to reach the buried insulating film, thereby forming the diaphragm portion. A method for manufacturing a semiconductor pressure sensor, wherein the pressure sensor is formed. 3. A buried insulating layer is formed in the middle of the thickness direction.
A method of manufacturing a semiconductor pressure sensor using a semiconductor substrate having a support layer formed on the back surface side of the buried insulating layer and an active layer formed on the main surface side, comprising: forming a back surface insulating film on the back surface side of the support layer. After forming and providing an opening window for forming a pressure inlet in the backside insulating film, using this backside insulating film as a mask, etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer to the ratio of the backside insulating film. And a diaphragm portion is formed by simultaneously removing a portion of the support layer exposed from the opening window and the back surface insulating film, and providing a pressure introduction port reaching the buried insulating film. Production method. 4. A buried insulating layer is formed in the middle of the thickness direction.
A method of manufacturing a semiconductor pressure sensor using a semiconductor substrate having a support layer formed on the back surface side of the buried insulating layer and an active layer formed on the main surface side, comprising: forming a back surface insulating film on the back surface side of the support layer. After forming the film, the back surface insulating film is etched from the back surface side to form a film having a desired thickness, an opening window for forming a pressure inlet is formed in the back surface insulating film, and the back surface insulating film is masked. The etching is performed by adjusting the etching selectivity to the ratio of the thickness of the support layer to the ratio of the back surface insulating film, and simultaneously removing the portion of the support layer exposed from the opening window and the back surface insulating film to form a buried insulating film. A method for manufacturing a semiconductor pressure sensor, wherein a diaphragm portion is formed by providing a pressure introduction port to reach. 5. A buried insulating layer is formed in the middle of the thickness direction.
A method of manufacturing a semiconductor pressure sensor using a semiconductor substrate having a support layer formed on the back surface side of the buried insulating layer and an active layer formed on the main surface side, wherein a desired thickness is formed on the back surface side of the support layer. After forming the back surface insulating film, an opening window for forming a pressure introduction port is provided in the back surface insulating film, and using this back surface insulating film as a mask, the etching selectivity is determined by the ratio of the thickness of the support layer to the back surface insulating film. It is characterized in that the diaphragm portion is formed by removing the portion of the support layer exposed from the opening window and the back surface insulating film at the same time, and providing a pressure introduction port reaching the buried insulating film. Of manufacturing a semiconductor pressure sensor.