JP5302596B2 - Solid state vacuum device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid vacuum device that can have high performance. <P>SOLUTION: A thermal device element portion 20 supported by a first polysilicon layer 12 is formed on one surface side of a silicon substrate 10, and a cap portion 40 for vacuum sealing is formed enclosing the thermal device element portion 20. The cap portion 40 for vacuum sealing includes: a porous portion 42 for vacuum sealing, the porous portion being formed by subjecting, to anodic oxidation, part of a second polysilicon layer 41 formed on the one surface side of the silicon substrate 10; and a cap layer 43 laminated on the porous portion 42 for vacuum sealing. A first space 15 of the thermal device element portion 20 on the side of the silicon substrate 10 and a second space 35 on the side of the cap portion 40 for vacuum sealing are evacuated. The solid vacuum device includes a heat insulation portion 13 comprised of a porous polysilicon portion formed by subjecting part of the first polysilicon layer 12 to anodic oxidation and thermally insulating the thermal device element portion 20 and silicon substrate 10. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a solid-state vacuum device.

  2. Description of the Related Art Conventionally, there is known a solid-state vacuum device that is formed by using surface micromachining technology or the like using a single semiconductor substrate (such as a silicon substrate) without using a plurality of substrates (for example, non-patent) Reference 1).

  Here, the solid-state vacuum device disclosed in Non-Patent Document 1 is arranged on one surface side of the silicon substrate 110 so as to be spaced apart from the silicon substrate 110, as shown in FIG. A thermal device element portion (here Pirani gauge) 120 supported by the first polysilicon layer 112 on the side is formed, and vacuum sealing is performed so as to surround the thermal device element portion 120 on the one surface side of the silicon substrate 110. A stopper cap 140 is formed, and the vacuum sealing cap 140 is formed by anodizing a part of the second polysilicon layer 141 formed on the one surface side of the silicon substrate 110. A porous portion 142 for vacuum sealing made of a polysilicon portion, and micropores of the porous portion 142 for vacuum sealing laminated on the porous portion 142 for vacuum sealing And a cap layer 143 and sealing the second space 135 of the first space 115 and the vacuum sealing cap 140 of the silicon substrate 110 side is a vacuum in the thermal device elements 120. In the above solid-state vacuum device, the distance between the vacuum sealing cap 140 and the one surface of the silicon substrate 110 is defined by the film thickness of the PSG film 114 patterned in a predetermined shape. A pad 129 electrically connected to the thermal device element 120 is formed on the exposed portion of the polysilicon layer 112.

  Hereinafter, a method of manufacturing the solid-state vacuum device having the configuration shown in FIG. 14 will be briefly described with reference to FIG.

  First, an insulating film 111 made of a silicon nitride film having a thickness of 500 nm is formed on the one surface of the silicon substrate 110 by the LPCVD method, and then a PSG film having a thickness of 1.5 μm (hereinafter referred to as “PSG film”) is formed on the insulating film 111. 113) (referred to as a first PSG film), and the first PSG film 113 is patterned so as to leave a portion corresponding to the first space 115, and then on the one surface side of the silicon substrate 110. A first polysilicon layer 112 having a thickness of 1 μm doped with impurities is formed by LPCVD, and then the first polysilicon layer 112 is patterned to obtain the structure shown in FIG. . Here, the portion of the first polysilicon layer 112 laminated on the first PSG film 113 constitutes the thermal device element unit 120.

  After the patterning of the first polysilicon layer 112, a PSG film 114 (hereinafter referred to as a second PSG film) 114 having a film thickness of 5 μm is formed on the one surface side of the silicon substrate 110, and the second PSG By patterning the film 114 and subsequently forming a contact hole 111a in the insulating film 111, the structure shown in FIG. 15B is obtained.

  Thereafter, a non-doped polysilicon layer 141a having a film thickness of 1.5 μm is formed on the one surface side of the silicon substrate 110 by the LPCVD method. Subsequently, a PSG film having a film thickness of 300 nm (hereinafter referred to as a third PSG film). 144) is formed by the LPCVD method to obtain the structure shown in FIG.

  Thereafter, annealing is performed by doping the polysilicon layer 141a with impurities in the third PSG film 144 to form a conductive second polysilicon layer 141, and then the third PSG film 144 is removed. Subsequently, a resist layer (not shown) patterned for forming a porous polysilicon portion is formed on the second polysilicon layer 141, and then a part of the second polysilicon layer 141 is formed as an anode. The structure shown in FIG. 15D is obtained by forming a vacuum sealing porous portion 142 made of a porous polysilicon portion by oxidation, and then removing the resist layer. Note that as an electrolytic solution for anodizing the part of the second polysilicon layer 141, a hydrofluoric acid-based solution in which 49% HF and ethanol are mixed at a ratio of 1: 1 is used.

  After removing the resist layer, RTA (Rapid Thermal Annealing) is performed to relieve stress. Subsequently, a part of the second PSG film 114 and the whole of the first PSG film 113 are vacuum-sealed. The second space 135 and the first space 115 are formed by selectively etching with 49% HF through the porous portion 142, thereby obtaining the structure shown in FIG.

  Thereafter, a cap layer 143 made of a polysilicon layer for vacuum sealing is formed on the one surface side of the silicon substrate 110 by a LPCVD method at a desired degree of vacuum (for example, 179 mTorr≈37 Pa). The structure shown in is obtained.

  Thereafter, the laminated film of the second PSG film 114, the second polysilicon layer 141, and the cap layer 143 on the one surface side of the silicon substrate 110 is patterned to expose a part of the first polysilicon layer 112. As a result, the structure shown in FIG.

Thereafter, a pad 129 electrically connected to the first polysilicon layer 112 is formed by a vapor deposition method, thereby obtaining the structure shown in FIG.
Rihui He, et al, “On-Wafer Monolithic Encapsulation by Surface Micromachining With Porous Polysilicon Shell”, JOURNAL OFMICROELECTROMECHANICAL SYSTEMS, VOL.16, NO.2, p462-472, APRIL 2007

  By the way, in the solid-state vacuum device having the configuration shown in FIG. 14, heat insulation by vacuum is obtained, but the silicon substrate 110 is formed only by the silicon nitride film 111 on the one surface of the silicon substrate 110. It was difficult to achieve high performance because it was not insulated. The thermal device element unit 120 in this type of solid-state vacuum device is not limited to Pirani gauge, and for example, a thermopile, a resistance bolometer, a micro heater, an infrared light source, and the like are conceivable.

  The present invention has been made in view of the above reasons, and an object thereof is to provide a solid-state vacuum device capable of improving performance.

The invention according to claim 1 is supported by a first polysilicon layer disposed on one surface side of the silicon substrate so as to be separated from the silicon substrate and surrounding the heat insulating portion on the one surface side of the silicon substrate and the heat insulating portion. was heated device elements portion is formed, the sheet of the vacuum sealing cap in a manner surrounding the thermal-type device element portion on one surface side of the silicon substrate is formed, the vacuum sealing cap portion, vacuum sealing the porous part made of multi porous polysilicon portion, a second polysilicon layer is formed continuously to the porous portion for the vacuum seal surrounding the said vacuum sealing porous portion, and a said true Sorafutome for porous section and the second is laminated on the polysilicon layer said true Sorafutome for porous section of the microporous cap layer has sealing, said thermal type device element section first space of the divorced substrate side that put in and the vacuum The second space sealing cap portion has a vacuum, the first space, and the silicon substrate is formed on the one surface of the silicon substrate and the silicon substrate and the first polysilicon layer And a space surrounded by the heat insulating portion and the first polysilicon layer, and the heat insulating portion is formed in a continuous manner with the first polysilicon layer. the a Ri Do from porous polysilicon portion and the heat-type device element portion and the sheet silicon substrate and wherein the benzalkonium be thermally insulated.

According to the present invention, since the silicon substrate first polysilicon layer to continuously form made was a porous polysilicon portions thermal device elements portion and a heat insulating portion for thermal insulation, thermal The heat insulation between the device element part and the silicon substrate can be enhanced, and high performance can be achieved.

  According to a second aspect of the present invention, in the first aspect of the present invention, the first polysilicon layer is formed with a slit that connects the first space and the second space.

  According to this invention, the stress of the first polysilicon layer can be relaxed and the heat insulation can be improved.

The invention of claim 3 is the invention of claim 1 or claim 2, wherein the heat insulating portion is not pure product is characterized in that it is doped.

  According to the present invention, since the heat insulating portion can be formed by anodizing the conductive region in the first polysilicon layer, the heat insulating portion can be easily formed with high positional accuracy.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the heat insulating part has a larger porosity than the vacuum sealing porous part.

  According to this invention, the heat insulation of the said heat insulation part can be improved by enlarging the porosity of the said heat insulation part.

The invention of claim 5 is the invention of claims 1 to 4, is formed continuously in the first polysilicon layer has at least one functional unit having a function different from that of the said cross-sectional thermal unit, the functional unit is made of a porous polysilicon portions, wherein the cross heat unit and at least one independently by the function portion respectively have set porosity.

According to the present invention, the characteristics of the cross-sectional heat unit and at least one functional unit can be independently designed, thereby the performance.

  The invention of claim 6 is the invention of claims 1 to 5, wherein the thermal type device element portion is a thermopile, and the thermopile has a hot junction covered with an infrared absorption layer, and the infrared absorption layer contains impurities. It consists of a doped polysilicon layer.

  According to the present invention, the hot contact of the thermopile constituting the thermal device element portion is covered with the infrared absorbing layer, so that the sensitivity can be improved, and the infrared absorbing layer is made from the polysilicon layer doped with impurities. Therefore, the amount of infrared absorption can be increased by increasing the doping amount of the infrared absorption layer, and high sensitivity can be achieved.

A seventh aspect of the present invention is the infrared light source according to any one of the first to fifth aspects, wherein the thermal type device element portion is composed of a heat generating layer that emits infrared rays. formed continuously with the polysilicon layer, characterized in Rukoto a polysilicon layer non pure product was Doping.

According to the present invention, the a infrared light source comprising a heating element layer thermal device elements unit emits infrared, the heat generating layer is, the first formed continuously on the polysilicon layer not pure product the Doping polysilicon such a layer Runode, thereby stabilizing the radiating characteristics with attained the speed of the response speed of the infrared light source.

  The invention according to claim 8 is the invention according to any one of claims 1 to 5, wherein the thermal type device element portion is a resistance bolometer, and the resistance bolometer is constituted by a part of the first polysilicon layer. It is characterized by that.

  According to this invention, since the thermal device element part is a resistance bolometer constituted by a part of the first polysilicon layer, the thermal device element part can be easily formed.

The invention of claim 9 is the invention of claim 6 through claim 8, wherein the first space is formed by providing a concave plant to the one front side of the silicon substrate, the inner surface of the recess infrared A concave mirror that reflects the light beam is configured.

  According to this invention, the infrared rays that have traveled from the thermal device element portion side to the first space side can be reflected to the thermal device element portion side by the concave mirror.

The invention of claim 10 is the invention of claim 6 of stone claim 9, wherein the vacuum sealing cap, the cap layer is constituted by a third polysilicon layer, as an infrared transmitting unit that transmits infrared It is characterized by functioning.

  According to this invention, infrared rays can be transmitted through the vacuum sealing cap portion, and loss of infrared rays can be suppressed from occurring in the vacuum sealing cap portion.

  According to an eleventh aspect of the present invention, in the sixth to tenth aspects of the present invention, the vacuum sealing cap portion includes a plurality of ring-shaped porous polysilicon portions concentrically as the vacuum sealing porous portion. The cap layer is formed of a third polysilicon layer, and functions as an infrared Fresnel lens optically coupled to the thermal device element.

  According to the present invention, the cost can be reduced as compared with the case where the Fresnel lens is formed separately from the vacuum sealing cap portion.

  According to a twelfth aspect of the present invention, in the sixth to tenth aspects of the present invention, the vacuum sealing cap portion has a plurality of annular zone-shaped porous polysilicon portions concentric separately from the vacuum sealing porous portion. The cap layer is formed of a third polysilicon layer and functions as an infrared Fresnel lens optically coupled to the thermal device element portion.

  According to the present invention, the cost can be reduced as compared with the case where the Fresnel lens is formed separately from the vacuum sealing cap portion.

  A thirteenth aspect of the invention is characterized in that in the first aspect of the invention, a capacitor is formed in which the vacuum sealing porous portion and a part of the first polysilicon layer are a pair of electrodes. To do.

  According to the present invention, it is possible to detect acceleration based on the output of the capacitor.

  In invention of Claim 1, the heat insulation between a thermal-type device element part and a silicon substrate can be improved, and there exists an effect that performance enhancement is attained.

(Embodiment 1)
As shown in FIG. 1, the solid-state vacuum device of the present embodiment is arranged on one surface side of a silicon substrate 10 so as to be spaced apart from the silicon substrate 10, and the first polysilicon layer on the one surface side of the silicon substrate 10. 12 is formed, and a vacuum sealing cap 40 is formed on the one surface side of the silicon substrate 10 so as to surround the thermal device element 20. A vacuum sealing porous portion 42 comprising a porous polysilicon portion formed by anodizing a portion of the second polysilicon layer 41 formed on the one surface side of the silicon substrate 10; And a cap layer 43 laminated on the vacuum sealing porous portion 42 and sealing the micropores of the vacuum sealing porous portion 42, and the second layer on the silicon substrate 10 side in the thermal device element portion 20. Second space 35 of the space 15 and the vacuum sealing cap 40 side is in the vacuum.

  In addition, the solid-state vacuum device of the present embodiment includes a porous polysilicon portion formed by anodizing a part of the first polysilicon layer 12, and heats the thermal device element portion 20 and the silicon substrate 10. The heat insulation part 13 to insulate is provided. Here, the first polysilicon layer 12 is formed on the one surface side of the silicon substrate 10 via the silicon oxide film 11, and the first polysilicon layer 12 is formed between the heat insulating portion 13 and the silicon substrate 10. The gap length of the space 15 is defined by the thickness of the silicon oxide film 11.

  Further, in the solid-state vacuum device of the present embodiment, the first polysilicon layer 12 and the heat insulating portion 13 have conductivity, and the first polysilicon layer 12 and the heat insulating portion 13, the thermal device element portion 20, A first insulating film 14 made of a thin silicon nitride film that electrically insulates the first polysilicon layer 12 and the heat insulating portion 13 is formed.

  In the solid-state vacuum device of the present embodiment, the second polysilicon layer 41 and the vacuum sealing porous portion 42 have conductivity, and the second polysilicon layer 41 and the thermal device element portion 20 Is formed on the surface side of the first insulating film 14 and is electrically connected to the thermal device element portion 21. Pads 29, 29 made of a film (for example, an Al film, an Al—Si film, etc.) are formed so as to fill the contact holes 31 a, 31 a formed in the second insulating film 31.

  The solid-state vacuum device of the present embodiment is an infrared sensor, and the thermal device element unit 20 is configured by a thermopile. Here, the thermopile serving as the thermal device element unit 20 is composed of an n-type polysilicon layer 21 and a p-type polysilicon layer 22 each patterned in a predetermined shape on the first insulating film 14. A contact point between the silicon layer 21 and the p-type polysilicon layer 22 constitutes a hot contact point. If this hot junction is covered with an infrared absorption layer, the sensitivity can be increased, and if the infrared absorption layer is made of a polysilicon layer doped with impurities, the doping amount of the infrared absorption layer can be increased. Can increase the amount of infrared absorption and increase the sensitivity.

  Hereinafter, the manufacturing method of the solid-state vacuum device of this embodiment is demonstrated, referring FIGS.

  First, the structure shown in FIG. 2A is obtained by forming the silicon oxide film 11 on the entire surface of the single-crystal silicon substrate 10 on the one surface side by the CVD method or the thermal oxidation method.

  Thereafter, a non-doped polysilicon layer 12a is formed on the entire surface of the one surface side of the silicon substrate 10 by a CVD method or the like to obtain the structure shown in FIG. 2B, and then the entire non-doped polysilicon layer 12a is obtained. Then, the first polysilicon layer 12 having conductivity is formed by doping a p-type impurity over the distance, thereby obtaining the structure shown in FIG.

Thereafter, a resist layer 51 patterned for forming the heat insulating portion 13 is formed on the one surface side of the silicon substrate 10, and then a portion of the first polysilicon layer 12 is anodized to form porous polysilicon. By forming the heat insulating portion 13 composed of the portions, the structure shown in FIG. 2D is obtained. As an electrolytic solution for anodizing the part of the first polysilicon layer 12, a solution for removing SiO ₂ , which is an oxide of Si, which is a constituent element of the first polysilicon layer 12, is used. A hydrofluoric acid solution in which a 55 wt% aqueous solution of hydrogen fluoride and ethanol are mixed at a ratio of 1: 1 is used, but the concentration of the aqueous solution of hydrogen fluoride and the mixing ratio of the aqueous solution of hydrogen fluoride and ethanol are particularly limited. is not. Also, the liquid mixed with the aqueous hydrogen fluoride solution is not limited to ethanol, and is not particularly limited as long as it is a liquid that can remove bubbles generated by an anodizing reaction, such as alcohol such as methanol, propanol, and isopropanol (IPA). .

  After the formation of the heat insulating portion 13, the resist layer 51 is removed, and then the first insulating film 14 made of a silicon nitride film is formed on the entire surface of the one surface side of the silicon substrate 10. A polysilicon layer is deposited on the one surface side, and an n-type impurity layer is doped into the polysilicon layer and then patterned to form an n-type polysilicon layer 21 having a predetermined shape. A polysilicon layer is deposited on one surface side, p-type impurity is doped into the polysilicon layer, and then patterned to form a p-type polysilicon layer 22 having a predetermined shape. Subsequently, at least one of the heat insulating portions 13 is formed. 2 (e) is obtained by patterning the first insulating film 14 into a predetermined shape so that the portion is exposed (see FIG. 2 (e)). In cross section, the heat insulating portion 13 is not exposed).

  Thereafter, a silicon oxide film made of an NSG film is formed on the entire surface of the one surface side of the silicon substrate 10, and then the sacrificial layer 52 for forming the second space 35 is formed by patterning the silicon oxide film. Thus, the structure shown in FIG.

  Next, a non-doped polysilicon layer 41a is formed on the entire surface of the one surface side of the silicon substrate 10 by a CVD method or the like, thereby obtaining the structure shown in FIG.

  Thereafter, a PSG film 45 is formed on the polysilicon layer 41a to obtain the structure shown in FIG.

  Thereafter, the second polysilicon layer 41 having conductivity is formed by performing annealing for doping the polysilicon layer 41a with impurities in the PSG film 45, and then the PSG film 45 is removed, thereby removing the structure shown in FIG. The structure shown in d) is obtained.

Thereafter, a resist layer 53 patterned for forming the vacuum sealing porous portion 42 is formed on the one surface side of the silicon substrate 10, and then a part of the second polysilicon layer 41 is anodized. By forming a vacuum sealing porous portion 42 made of a porous polysilicon portion, the structure shown in FIG. 4A is obtained. In addition, as an electrolytic solution for anodizing the part of the second polysilicon layer 41, a solution for etching and removing SiO ₂ that is an oxide of Si that is a constituent element of the second polysilicon layer 41 is used. A hydrofluoric acid solution in which a 55 wt% aqueous solution of hydrogen fluoride and ethanol are mixed at a ratio of 1: 1 is used, but the concentration of the aqueous solution of hydrogen fluoride and the mixing ratio of the aqueous solution of hydrogen fluoride and ethanol are particularly limited. is not. Also, the liquid mixed with the aqueous hydrogen fluoride solution is not limited to ethanol, and is not particularly limited as long as it is a liquid that can remove bubbles generated by an anodizing reaction, such as alcohol such as methanol, propanol, and isopropanol (IPA). .

  After forming the above-described vacuum sealing porous portion 42, the resist layer 53 is removed, and then a sacrificial layer 52 made of a silicon oxide film immediately below the vacuum sealing porous portion 42 is formed into a vacuum sealing porous portion. The second space 35 is formed by selectively etching with a hydrofluoric acid-based solution (for example, hydrogen fluoride aqueous solution or the like) through the micropores of the portion 42, and the silicon oxide film 11 immediately below the heat insulating portion 13 is formed on the heat insulating portion 13. The first space 15 is formed by etching with the hydrofluoric acid solution through the fine holes, whereby the structure shown in FIG. 4B is obtained.

  Thereafter, the cap layer 43 made of the third polysilicon layer is laminated on the one surface side of the silicon substrate 10 to thereby form the vacuum seal cap portion 40 made of the vacuum seal porous portion 42 and the cap layer 43. By forming, the structure shown in FIG. 4C is obtained.

  Thereafter, after patterning the cap 40 for vacuum sealing, contact holes 31a and 31a are formed in the second insulating film 31, and then a conductive film (for example, Al) is formed on the one surface side of the silicon substrate 10. 4 (d) is obtained by forming the pads 29 and 29 by patterning the conductive film.

  In the solid-state vacuum device of the present embodiment described above, the thermal device element portion 20 and the silicon substrate 10 are formed of a porous polysilicon portion formed by anodizing a part of the first polysilicon layer 12. Since the heat insulating part 13 for heat insulation is provided, the heat insulating property between the thermal device element part 20 and the silicon substrate 10 can be improved, and high performance can be achieved.

  Here, in the solid-state vacuum device of the present embodiment, if the first polysilicon layer 12 is formed with a slit that allows the first space 15 and the second space 35 to communicate with each other, the first polysilicon layer 12 is formed. While being able to relieve the stress of the layer 12, it is possible to improve the heat insulation, and it is possible to further improve the performance of the thermal device element unit 20.

  In the solid-state vacuum device of this embodiment, as can be seen from the above description, the vacuum spaces 15 and 35 can be formed by a wafer process using surface micromachining technology or the like without using a plurality of substrates. The thermal type device element unit 20 is disposed in a vacuum, so that deterioration of the thermal type device element unit 20 due to the outside air can be suppressed and reliability can be improved. There is no need to use it, and the cost and size can be reduced.

  In the solid-state vacuum device of the present embodiment, the heat insulating portion 13 is formed by anodizing the conductive region that is part of the first polysilicon layer 12 and doped with impurities. The heat insulating part 13 can be easily formed with high positional accuracy.

  Moreover, in the solid vacuum device of this embodiment, the heat insulation of the heat insulation part 13 can be improved by making the porosity of the heat insulation part 13 larger than the porosity of the porous part 42 for vacuum sealing. Here, the porosity of the heat insulating portion 13 is set to 60%, but considering the heat insulating property and mechanical strength of the heat insulating portion 13 and the permeability of the hydrofluoric acid solution, for example, 40 to 80%. The porosity of the vacuum sealing porous portion 42 is, for example, in the range of 20 to 50% in consideration of the permeability of the hydrofluoric acid solution and the sealing property of the cap layer 43. And set as appropriate.

(Embodiment 2)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 5, the thermal device element unit 20 is an infrared light source 23 composed of a heating element layer that emits infrared rays. The difference is that the heating element layer as the infrared light source 23 is formed of a metal film (for example, a Pt film). In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Thus, according to the solid-state vacuum device of the present embodiment, since the infrared light source 23 is thermally insulated from the silicon substrate 10 by the heat insulating portion 13, the response speed of the infrared light source 23 can be increased and radiation characteristics can be improved. Stabilize. By the way, in this embodiment, although the heat generating body layer as the infrared light source 23 is comprised with the metal film, a heat generating body layer is formed by doping a predetermined area | region of a 1st polysilicon layer with an impurity. In addition, the resistivity of the heating element layer can be controlled by appropriately adjusting the doping amount.

  Further, in the solid vacuum device of the present embodiment, as in the first embodiment, since the cap layer 43 is formed of the third polysilicon layer, the vacuum sealing cap portion 40 is an infrared transmitting portion that transmits infrared rays. It functions, and while being able to transmit infrared rays through the vacuum sealing cap portion 40, it is possible to suppress loss of infrared rays in the vacuum sealing cap portion 40.

(Embodiment 3)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 6, the first space 15 is formed by anodizing a part of the one surface side of the silicon substrate 10. The formed porous portion is oxidized and etched to provide the recess 10c on the one surface. Here, in the present embodiment, the curved surface that is the inner surface of the recess 10c on the one surface side of the silicon substrate 10 can function as a concave mirror, and the first space from the thermal device element unit 20 side. Since the infrared ray traveling toward the 15 side can be reflected to the thermal device element unit 20 side by the concave mirror, the infrared ray incident on the curved surface can be condensed at the hot junction, thereby improving the infrared detection sensitivity. be able to. This curved surface can be formed by a curved surface forming method of forming a curved surface by giving an in-plane distribution to the current density of anodic oxidation. Since other configurations are the same as those of the first embodiment, description thereof is omitted. In other embodiments, a recess 10c similar to that of the present embodiment may be provided in the silicon substrate 10. For example, in the second embodiment, infrared light is an infrared light source that is the thermal device element unit 20 using a concave mirror. By reflecting to the 23 side, infrared rays can be collected and emitted.

(Embodiment 4)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 7, the thermal type device element unit 20 anodizes the first polysilicon layer 12 having conductivity. It is comprised by the resistance bolometer 25 which consists of the porous silicon part formed by doing, and the point which serves as the heat insulation part 13 is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Therefore, in the solid-state vacuum device of this embodiment, manufacture becomes easy compared with the case where the thermal type device element part 20 is comprised with a thermopile like Embodiment 1. FIG.

(Embodiment 5)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the fourth embodiment. As shown in FIG. 8, the size of the vacuum sealing porous portion 42 in the vacuum sealing cap portion 40 is reduced. The difference is that a plurality of vacuum sealing porous portions 42 are formed. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Therefore, in the solid vacuum device of the present embodiment, since the size of the vacuum sealing porous portion 42 in the vacuum sealing cap portion 40 is reduced and a plurality of vacuum sealing porous portions 42 are formed, The mechanical strength of the cap 40 for vacuum sealing can be increased, and further higher vacuum can be achieved in the first space 15 and the second space 35.

(Embodiment 6)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the fifth embodiment, and as shown in FIG. 9, the thermal device element unit 20 is a conductive material doped with impurities in the non-doped first polysilicon layer 12a. The difference is that it is constituted by a resistance bolometer 26 made of a conductive region. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Thus, in the solid-state vacuum device of the present embodiment, the thermal device element unit 20 is a resistance bolometer 26, and the resistance bolometer 26 is formed of a conductive region doped with impurities in the non-doped first polysilicon layer 12a. Since it is configured by the resistance bolometer 26, the thermal device element portion 20 can be easily formed, and the infrared absorption efficiency can be increased by increasing the impurity doping amount.

  By the way, when the heat insulating portion 13 is formed by anodizing a conductive region doped with impurities as a part of the first polysilicon layer 12a as in this embodiment, as shown in FIG. In addition, pads 12c and 12c for energization when the conductive region is anodized are provided, and the pads 12c and 12c are constituted by conductive regions doped with impurities in the first polysilicon layer 12a. Also good. In the example shown in FIG. 10, since the slits 12b and 12b penetrating in the thickness direction are formed in the first polysilicon layer 12a, the stress of the first polysilicon layer 12a can be relieved. , Heat insulation can be improved.

  Further, in the solid-state vacuum device of the present embodiment, functional parts such as a wiring part and an infrared absorption part which are formed by anodizing a predetermined part of the first polysilicon layer 12a and have a function different from that of the heat insulating part 13 are provided. Thus, the porosity may be set independently for each of the heat insulating portion 13 and the at least one functional portion. In this case, the characteristics of the heat insulating portion 13 and the at least one functional portion are designed independently. Can improve performance. Note that the same configuration may be adopted as appropriate in other embodiments.

(Embodiment 7)
The basic configuration of the solid vacuum device of the present embodiment is substantially the same as that of the sixth embodiment. As shown in FIG. 11, in the vacuum sealing cap portion 40, a plurality of annular zones are used as the vacuum sealing porous portion 42. The porous polysilicon portion is formed, the cap layer 43 is constituted by the third polysilicon layer, and functions as an infrared Fresnel lens optically coupled to the thermal device element portion 20. To do. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 6, and description is abbreviate | omitted.

  Therefore, in the solid-state vacuum device of this embodiment, it is possible to reduce the cost and size as compared with the case where the Fresnel lens is formed separately from the vacuum sealing cap portion 40, and the optical axis alignment is unnecessary. Thus, since there is no occurrence of optical axis misalignment due to assembly variation or the like, reliability can be improved. In addition, you may employ | adopt the structure of the cap part 40 for vacuum sealing of this embodiment in other embodiment.

  By the way, in this embodiment, a plurality of ring-shaped porous polysilicon portions are concentrically formed as the vacuum sealing porous portion 42. However, as shown in FIG. A plurality of ring-shaped porous silicon portions 45 for forming a Fresnel lens using a refractive index change may be formed concentrically inside the material portion 42. Here, the porous portion 42 for vacuum sealing needs to be formed in the entire thickness direction of the second polysilicon layer 41, but the porous silicon portion 45 for forming the Fresnel lens is formed by the second polysilicon layer. It is not necessary to form the entire 41 in the thickness direction.

(Embodiment 8)
The basic configuration of the solid-state vacuum device of the present embodiment is substantially the same as that of the fourth embodiment. As shown in FIG. 13, a pair of the vacuum sealing porous portion 42 and a part of the first polysilicon layer 12 are paired. The difference is that a capacitor is formed as an electrode. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 4, and description is abbreviate | omitted.

  In the solid-state vacuum device of this embodiment, the distance between the pair of electrodes changes due to acceleration, and the capacitance of the capacitor changes.

  Thus, in the solid-state vacuum device of the present embodiment, acceleration can be detected based on the output of the capacitor, and the detected acceleration is temperature-corrected based on the output of the resistance bolometer 25 made of a porous silicon portion. It becomes possible.

  By the way, in the solid-state vacuum device of the present embodiment, an IC unit (for example, a signal processing circuit that performs signal processing on the output of the thermal device element unit 20) that cooperates with the thermal device element unit 20 is integrated on the silicon substrate 10. For example, the wiring length between the thermal device element unit 20 and the IC unit can be shortened to reduce noise, and the size can be reduced as compared with the case where the IC unit is formed on another substrate. In addition, the cost can be reduced. Moreover, you may form several thermal type device element part 20 in the array form in the said one surface side of the one silicon substrate 10, and in Embodiment 1, 3-7, the thermal type device element part 20 is arranged in an array form. By forming it, it can be developed as a thermal image device.

1 is a schematic cross-sectional view showing a first embodiment. It is principal process sectional drawing for demonstrating the manufacturing method same as the above. It is principal process sectional drawing for demonstrating the manufacturing method same as the above. It is principal process sectional drawing for demonstrating the manufacturing method same as the above. FIG. 6 is a schematic cross-sectional view showing a second embodiment. FIG. 6 is a schematic cross-sectional view showing a third embodiment. FIG. 6 is a schematic cross-sectional view showing a fourth embodiment. FIG. 6 is a schematic cross-sectional view showing a fifth embodiment. FIG. 9 is a schematic cross-sectional view showing a sixth embodiment. It is a principal part schematic plan view in the other structural example same as the above. FIG. 10 is a schematic cross-sectional view showing a seventh embodiment. It is a schematic sectional drawing which shows the other structural example same as the above. 10 is a schematic cross-sectional view showing an eighth embodiment. FIG. It is a schematic sectional drawing which shows a prior art example. It is principal process sectional drawing for demonstrating the manufacturing method same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Silicon substrate 10c Recess 11 Silicon oxide film 12 1st polysilicon layer 13 Heat insulation part 14 1st insulating film 15 1st space 20 Thermal type device element part 23 Infrared light source 25 Resistance bolometer 26 Resistance bolometer 35 2nd 40 Vacuum sealing cap part 41 Second polysilicon layer 42 Vacuum sealing porous part 43 Cap layer 45 Porous polysilicon part

Claims (13)

A thermal type device element portion disposed on one surface side of the silicon substrate and spaced apart from the silicon substrate and supported by the first polysilicon layer surrounding the heat insulating portion and the heat insulating portion on the one surface side of the silicon substrate. is formed, the above cap for vacuum sealing in a manner surrounding the thermal-type device element portion on one surface side of the silicon substrate is formed, the vacuum sealing cap portion, from the multi-porous polysilicon portion vacuum sealing the porous part made of a second polysilicon layer is formed continuously to the porous portion for the vacuum seal surrounding the said vacuum sealing porous portion, said true Sorafutome for porosity and a quality unit and the second is laminated on the polysilicon layer said true Sorafutome for porous section of the microporous cap layer that sealing the said sheet silicon substrate that put on the thermal-type device element section side first space and the vacuum sealing cap portion Second space has become a vacuum, the first space is silicon interposed between the silicon substrate and the formed on one surface of the silicon substrate and the first polysilicon layer of the silicon substrate and oxide film, the insulating part and made from a space surrounded by said first polysilicon layer, the heat insulating portion, from the multi-porous polysilicon portion formed continuously to said first polysilicon layer solid vacuum device, wherein the benzalkonium be thermally insulated from Do Ri said thermal-type device element portion and the divorced substrate.   2. The solid-state vacuum device according to claim 1, wherein a slit for communicating the first space and the second space is formed in the first polysilicon layer. The heat insulating unit, according to claim 1 or claim 2 solid vacuum device according non pure product is characterized in that it is doped.   4. The solid vacuum device according to claim 1, wherein the heat insulating portion has a larger porosity than the vacuum sealing porous portion. 5. Having at least one functional unit having a function different from that of the formed continuously on the first polysilicon layer and the cross heat unit, the functional unit is made of a porous polysilicon portion, the sectional heat unit and solid vacuum device according to any one of claims 1 to 4, characterized in that is set porosity independently in each of the at least one of the function unit.   The thermal type device element portion is a thermopile, and the thermopile is formed of a polysilicon layer in which a hot junction is covered with an infrared absorption layer and the infrared absorption layer is doped with impurities. The solid-state vacuum device according to any one of 5. Wherein an infrared light source comprising a heating element layer thermal device elements unit emits infrared, the heat generating layer, the first formed continuously on the polysilicon layer polysilicon Doping non pure product solid vacuum device according to any one of claims 1 to 5, characterized in Rukoto such a layer.   The thermal type device element portion is a resistance bolometer, and the resistance bolometer is constituted by a part of the first polysilicon layer. The described solid state vacuum device. Said first space, claim wherein said silicon substrate is formed by providing a concave plants on one front surface, the inner surface of the recess, characterized in that it constitutes a concave mirror for reflecting infrared 6 The solid vacuum device according to claim 8.   10. The vacuum sealing cap portion according to claim 6, wherein the cap layer is formed of a third polysilicon layer and functions as an infrared transmitting portion that transmits infrared light. 11. A solid vacuum device as described in 1.   In the vacuum sealing cap portion, a plurality of ring-shaped porous polysilicon portions are concentrically formed as the vacuum sealing porous portion, and the cap layer is constituted by a third polysilicon layer. 11. The solid-state vacuum device according to claim 6, which functions as an infrared Fresnel lens optically coupled to the thermal device element unit.   In addition to the vacuum sealing porous portion, the vacuum sealing cap portion includes a plurality of ring-shaped porous polysilicon portions concentrically formed, and the cap layer is formed of a third polysilicon layer. The solid-state vacuum device according to any one of claims 6 to 10, wherein the solid-state vacuum device is configured and functions as an infrared Fresnel lens optically coupled to the thermal device element section.   2. The solid vacuum device according to claim 1, wherein a capacitor having a pair of electrodes, the porous portion for vacuum sealing and a part of the first polysilicon layer, is formed.

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