JP2002344036A - Manufacturing method of membrane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a membrane for which there is no need for it to be subjected to a doubled-side patterning, capable of keeping a device to be free of contamination, and has high mechanical strength. SOLUTION: A membrane, which is formed on a board composed of an etching layer and a support board, is arranged separately from the support board by a space equal to the thickness of the etching layer, and the etching layer is etched from a membrane side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a superconducting radiation detector and, more particularly, to a method for producing a membrane for controlling heat conduction.

[0002]

2. Description of the Related Art At present, calorimeters using a superconducting transition edge are being developed by various research institutions. References include, for example, Applied Physics Letters 66, 1988 (1995). The calorie meter consists of an absorber that absorbs radiation and converts the energy of the radiation into heat energy, a resistor attached to the absorber that converts this heat energy into an electric signal, and a membrane that emits heat to the outside Have been. The calorie meter maintains a steady state by balancing the Joule heat generated by the current flowing through the resistor with the heat released to the outside through the membrane. The membrane uses a thin insulator with a thickness of about 1 μm to which micromachine technology is applied. A silicon nitride film is used as an insulator.

[0003]

A conventional method of fabricating a membrane is to use a silicon substrate on which at least one-sided silicon nitride is formed, to form an absorber and a resistor on the surface on which the silicon nitride is formed, and then from the back side. A method of etching silicon was used (Reference: IEEE Trans. Appl. Su)
per. 5,2690 (1995)). Further, in the conventional method, since silicon is etched from the back surface, it is necessary to perform double-sided patterning. For this reason, since both surfaces of the wafer are grounded to the exposure device holder, there is a concern that the elements may be contaminated. Further, when silicon is etched from the back surface, the entire thickness of the wafer is etched, so that the mechanical strength is expected to be weak. In particular, when an array of calorimeters is used, it is necessary to etch the back surface by the number of arrays, and it is expected that the mechanical strength of the entire substrate will be further reduced.

[0004]

In order to achieve the above object, a component of a microcalorimeter that realizes high energy resolution and high speed response by using a superconducting transition edge and using negative feedback, In a method for producing a membrane for determining thermal conductivity, the membrane is produced on a substrate composed of an etching layer and a support substrate, and the membrane is arranged at a distance of the thickness of the support substrate and the etching layer. A method for manufacturing a membrane in which an etching layer was etched from the side was used. As a result, since the membrane is arranged to be separated from the supporting substrate by the thickness of the etching layer, the membrane can be easily separated from the supporting substrate by etching only the etching layer. In addition, since the supporting substrate is not etched by etching from the membrane side, the strength of the substrate does not lower than before the etching. As described above, as compared with the conventional membrane manufacturing method, a membrane manufacturing method capable of manufacturing a calorie meter by a process from one side and improving the mechanical strength of the entire element was obtained.

[0005] Further, the present invention is a component of a microcalorimeter which realizes high energy resolution and high-speed response by utilizing a superconducting transition edge and using negative feedback. A thin film layer for fabricating a membrane, a thin insulating layer below the thin film layer, and a substrate having a three-layer structure of a supporting substrate below the insulating layer are used, and the thin film layer is patterned into a membrane shape. A method for fabricating a membrane in which a thin insulating layer and a supporting substrate were etched from the side was used. According to the present invention, after the thin film layer is patterned into a membrane, the thin insulating film is etched, and the supporting substrate is etched. Only the layers can be etched. As a result, since the patterning of the device is all performed from the surface, there is no fear that the device is contaminated during the patterning. Further, when the crystal plane of the support substrate is (100), if the direction of the membrane is arranged in parallel with the <100> direction of the support substrate, the thin insulating layer below the membrane can be efficiently etched. In addition, when the membrane is single-crystal thin silicon, the mechanical strength is particularly higher than that of amorphous silicon, and therefore, there is an advantage that the membrane is not broken by bubbles generated when etching the support substrate. As described above, as compared with the conventional membrane production method, a membrane production method capable of producing a calorimeter by a process from one side was obtained. Also,
By using a substrate in which an etching stop layer, an etching layer, an insulating layer, and a thin film layer are stacked on a supporting substrate, if the supporting substrate is sufficiently thick, even after the membrane is manufactured,
The thickness of the substrate is almost the same as before the etching of the etching layer. As a result, the mechanical strength of the element hardly changes before and after etching, and therefore, the manufacturing method of the present invention is optimal particularly when a plurality of microcalorimeters are manufactured on the same substrate.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIGS. 1 to 3 show components of a microcalorimeter which realizes high energy resolution and high speed response by using a superconducting transition edge and using negative feedback. In a method for producing a membrane for determining thermal conductivity, the membrane is produced on a substrate composed of an etching layer and a support substrate, and the membrane is arranged at a distance of the thickness of the support substrate and the etching layer. It is the schematic diagram showing the manufacturing method of the membrane which etches an etching layer from the side. FIGS. 1 (a), 2 (a), and 3 (a) show views of each step as viewed from the side, and FIGS. 1 (b), 2 (b), and 3 (b) FIG. 1 (a) to FIG. 3 (a) show diagrams when viewed, and FIG. 1 (b)
FIG. 3 is a cross-sectional view taken along line AA ′ shown in FIG.

As a substrate to be used, an etching layer 2 and a thin thin film layer 3 for forming a membrane are laminated on a supporting substrate 1. The material of the etching layer 2 is the etching layer 2
When etching the support substrate 1, the etchant is
It is necessary to select a material that does not etch the thin film layer 3.
For example, when the support substrate 1 and the thin film layer 3 are made of silicon,
Silicon dioxide can be selected as the material of the etching layer 2. The thickness of the etching layer 2 is desirably at least 2 μm or more for etching by wet etching. The mechanical strength can be improved as the thickness of the thin film layer 3 increases, but it must be reduced in order to absorb as little radiation as possible. For example, when silicon is used as the thin film layer 3, 1 μm to 10 μm
Desirably.

Next, a manufacturing method will be described. FIG.
This shows a step of patterning the thin film layer 3 into a membrane. 1 (b) is a top view, and FIG. 1 (a) is A in FIG. 1 (b).
It is sectional drawing which followed the -A 'line. The thin film layer 3 of the substrate in which the etching layer 2 and the thin thin film layer 3 for forming the membrane are laminated on the supporting substrate 1 is patterned into a membrane shape. When the thin film layer 3 is silicon, the etching layer 2 is silicon dioxide, and the support substrate 1 is silicon,
The thin film layer 3 can be patterned by dry etching. As dry etching, for example, Reactive
Ion Etching (RIE) can be used, and SF6 can be used as a reaction gas. Oxygen may be added as needed.

FIG. 2 shows an absorber 5 for absorbing radiation and a resistor 4 for changing the resistance value by the heat generated by the absorber 5.
4A and 4B are diagrams illustrating a process of forming a superconducting wiring 6. FIG.
2B is a top view, and FIG. 2A is a cross-sectional view taken along line AA ′ of FIG. 2B. As shown in FIG. 1, a metal film to be a resistor 4 is formed on a substrate patterned in a membrane shape. The metal used as the resistor 4 has a single layer of a superconductor or a laminated structure of a superconductor and a normal conductor. By using the laminated structure, it is possible to lower the superconducting transition temperature of the superconductor single layer (proximity effect), and it is possible to change the thickness ratio between the superconducting layer and the normal conducting layer according to the purpose. . An absorber 5 for absorbing radiation is formed on the resistor 4. The absorber 5 may be a superconductor or a normal conductor. After that, the superconducting wiring 6 is manufactured. As the material of the resistor, for example, a two-layer structure of gold (normal conductor) and titanium (superconductor), gold as an absorber, and niobium as a superconducting wiring can be used. As a result, the superconducting transition temperature can be set to, for example, around 0.5K.

FIG. 3 is a schematic view showing a step of etching the etching layer 2 by wet etching. FIG. 3B is a top view, and FIG.
FIG. 3 is a cross-sectional view along the line. When silicon dioxide is used as the etching layer, a hydrogen fluoride solution can be used as a wet etching solution. The hydrogen fluoride solution hardly etches the thin film layer 3 and silicon which is the supporting substrate 1, but can easily etch silicon dioxide. After the production of the superconducting wiring 6 shown in FIG. 2, a protective film is applied on the front surface of the element, and only holes for etching the etching layer 2 are formed. For example, a resist can be used as the protective film. When the element coated with the resist is immersed in a hydrogen fluoride solution, silicon dioxide starts to be etched. The etching layer 2 below the membrane 7 is etched, and finally, the membrane 7 is disposed so as to be separated from the support substrate 1 by the thickness of the etching layer 2. The support substrate 1
Hardly etched by hydrogen fluoride solution. If the supporting substrate 1 is sufficiently thick, even after the etching layer 2 is etched, the thickness of the substrate is almost the same as before etching.
As a result, the mechanical strength of the element hardly changes before and after etching, and therefore, the manufacturing method of the present invention is optimal particularly when a plurality of microcalorimeters are manufactured on the same substrate.

A component of a microcalorimeter that realizes high energy resolution and high-speed response by utilizing a superconducting transition edge and using negative feedback. In a method of manufacturing a membrane for determining thermal conductivity, the membrane is etched. It is manufactured on a substrate composed of a layer and a support substrate, the membrane is arranged at a distance of the thickness of the support substrate and the etching layer, and by using a method of manufacturing a membrane in which the etching layer is etched from the membrane side. Since the membrane is disposed so as to be separated from the supporting substrate by the thickness of the etching layer, by etching only the etching layer,
The membrane can be easily separated from the supporting substrate. In addition, since the supporting substrate is not etched by etching from the membrane side, the strength of the substrate does not lower than before the etching. As described above, as compared with the conventional membrane manufacturing method, a membrane manufacturing method capable of manufacturing a calorie meter by a process from one side and improving the mechanical strength of the entire element was obtained. [Embodiment 2] FIGS. 4 to 8 show components of a microcalorimeter which realizes high energy resolution and high-speed response by using a negative feedback and utilizing a superconducting transition edge, and a membrane for determining thermal conductivity. In the manufacturing method, a thin film layer for manufacturing a membrane as a substrate, a thin insulating layer below the thin film layer made of silicon, and a substrate having a three-layer structure below the insulating layer are used, and the thin film layer is formed into a membrane shape. FIG. 4 is a schematic view showing a method for producing a membrane in which a thin insulating layer and a supporting substrate are etched from the membrane side after patterning.

FIGS. 4 (a), 5 (a), 6 (a) and 7 (a)
FIGS. 4 (b), 5 (b), and 6 show views of the respective steps as viewed from the side.
7 (b) and FIG. 7 (a) show diagrams when viewed from the front side, and FIG.
7A to 7A are cross-sectional views taken along line AA ′ shown in FIGS. 4B to 7B.

The substrate used is an insulating layer 1 on a supporting substrate 10.
1 and a thin film layer 12 for producing a membrane. It is necessary to select a material for the insulating layer 11 that does not etch the support substrate 10 and the thin film layer 12 when the insulating layer 11 is etched. For example, the support substrate 10 and the thin film layer 1
When 2 is silicon, the material of the thin film layer 11 is 2
Silicon oxide can be chosen. The thickness of the insulating layer 11 is
When the support substrate 10 is etched, the thin film layer 12 is used because it is not etched.
It is desirable that the thickness be 1 μm or more. Although the mechanical strength can be improved as the thickness of the thin film layer 12 increases, it must be reduced in order to absorb as little radiation as possible. For example, when silicon is used for the thin film layer 12, the thickness is desirably about 1 μm to 10 μm.

Next, a manufacturing method will be described. FIG.
This represents a step of patterning the thin film layer 12 into a membrane. The thin film layer 12 of the substrate in which the insulating layer 11 and the thin film layer 12 for forming the membrane are laminated on the support substrate 10 is patterned into a membrane shape. When the thin film layer 12 is silicon, the insulating layer 11 is silicon dioxide, and the support substrate 10 is silicon, the thin film layer 12 can be patterned by dry etching. For example, Reactive Ion Etching (RIE) can be used as dry etching, and SF6 can be used as a reaction gas.
Oxygen may be added as needed.

FIG. 5 is a schematic view showing a step of forming a protective film 13 on the surface of the thin film layer 12 after patterning the thin film layer 12 into a membrane shape. The protective film 13 is provided to protect the thin film layer 12 from being etched when the support substrate 10 is etched in the next step. When the thin film layer 12 and the support substrate 10 are made of silicon, the protective film 13 can be made of, for example, silicon nitride or silicon dioxide. As silicon nitride or silicon dioxide, for example, plasma Chemical Vapor Deposition (CVD) can be used. In the case of silicon dioxide, thermal oxidation can be used.

FIG. 6 shows that the supporting substrate 10
FIG. 4 is a diagram showing a process of forming an absorber 16 for providing a hole 14 for etching to absorb radiation, a resistor 15 for changing a resistance value by heat generated by the absorber 16, and a superconducting wiring 17. As shown in FIG. 5, a metal film to be the resistor 15 is formed on the membrane on which the protective film 13 has been formed. The metal used as the resistor 15 has a single layer of a superconductor or a laminated structure of a superconductor and a normal conductor. By using the laminated structure, it is possible to lower the superconducting transition temperature of the superconductor single layer (proximity effect), and it is possible to change the thickness ratio between the superconducting layer and the normal conducting layer according to the purpose. . Absorber 1 for absorbing radiation on resistor 15
6 is produced. The absorber 16 may be a superconductor or a normal conductor. After that, the superconducting wiring 17 is manufactured. As the material of the resistor, for example, a two-layer structure of gold (normal conductor) and titanium (superconductor), gold as an absorber, and niobium as a superconducting wiring can be used. as a result,
The superconducting transition temperature can be set, for example, to around 0.5K.

FIG. 7 shows the supporting substrate 1 below the membrane 18.
It is a schematic diagram showing the process of etching 0 by wet etching. When the support substrate 10 is silicon,
Hydrazine hydrate, KOH, T as wet etching solution
MAH can be used. Hydrazine hydrate, KO
H and TMAH hardly etch the thin film layer 12 protected by silicon nitride or silicon dioxide, but can easily etch silicon. After the production of the superconducting wiring 17 shown in FIG. 6, a protective film 13 which is not etched with an aqueous solution of hydrazine hydrate, KOH, TMAH or the like is formed on the front surface other than the etching hole 14 as necessary. For example, titanium can be used as the protective film 13. The element on which the protective film 13 was formed was replaced with hydrazine hydrate, KOH, TMAH
When immersed in an aqueous solution such as
0 starts to be etched. When the plane orientation of the support substrate 10 is (100), the orientation of the membrane 18 is set to <10
If 0>, the support substrate 10 can be efficiently etched. The support substrate 10 below the membrane 18 is etched, and finally, the membrane 18 is arranged so as to float in the air.

In particular, as shown in FIG.
When a substrate including the etching stop layer 22, the etching layer 23, the insulating layer 24, and the thin film layer 25 is used thereon, the thin film layer 25 is processed into a membrane shape by using the same steps shown in FIGS. 26, the etching layer 23 below is etched, and the etching is stopped by the etching stop layer, thereby leaving the thick support substrate 21.
It is possible to produce the membrane 26. The etching of the etching layer 23 can be performed by wet etching such as hydrazine hydrate. If the supporting substrate 21 is sufficiently thick, the thickness of the substrate is almost the same as before the etching of the etching layer 23 even after the membrane 26 is formed. As a result, the mechanical strength of the element hardly changes before and after etching, and therefore, the manufacturing method of the present invention is optimal particularly when a plurality of microcalorimeters are manufactured on the same substrate. It is preferable that the resistor 27, the absorber 28, and the superconducting wiring 29 be formed on the membrane 26 in advance before wet etching.

A component of a microcalorimeter that realizes high-energy resolution and high-speed response by utilizing a superconducting transition edge and using negative feedback. It is manufactured on a substrate composed of a layer and a support substrate, the membrane is arranged at a distance of the thickness of the support substrate and the etching layer, and by using a method of manufacturing a membrane in which the etching layer is etched from the membrane side. Since the membrane is arranged to be separated from the supporting substrate by the thickness of the etching layer, the membrane can be easily separated from the supporting substrate by etching only the etching layer. In addition, since the supporting substrate is not etched by etching from the membrane side, the strength of the substrate does not lower than before the etching. As described above, as compared with the conventional membrane manufacturing method, a membrane manufacturing method capable of manufacturing a calorie meter by a process from one side and improving the mechanical strength of the entire element was obtained. In addition, by using a substrate in which an etching stop layer, an etching layer, an insulating layer, and a thin film layer are stacked on a supporting substrate, if the supporting substrate is sufficiently thick, even after the membrane is formed, the etching layer is not etched. And the thickness of the substrate hardly changes. As a result, the mechanical strength of the element hardly changes before and after etching, and therefore, the manufacturing method of the present invention is optimal particularly when a plurality of microcalorimeters are manufactured on the same substrate.

[0020]

As described above, according to the first aspect of the present invention, it is a component of a microcalorimeter which realizes high energy resolution and high speed response by utilizing a superconducting transition edge and using negative feedback. In the method for producing a membrane for determining the conductivity, the membrane is produced on a substrate composed of an etching layer and a support substrate, and the membrane is arranged at a distance corresponding to the thickness of the support substrate and the etching layer. The method of fabricating a membrane in which an etching layer is etched from the substrate was used. As a result, since the membrane is arranged to be separated from the supporting substrate by the thickness of the etching layer, the membrane can be easily separated from the supporting substrate by etching only the etching layer. In addition, since the supporting substrate is not etched by etching from the membrane side, the strength of the substrate does not lower than before the etching. As described above, as compared with the conventional membrane manufacturing method, a membrane manufacturing method capable of manufacturing a calorie meter by a process from one side and improving the mechanical strength of the entire element was obtained.

According to a second aspect of the present invention, there is provided a micro-calorimeter component which realizes high energy resolution and high-speed response by using a superconducting transition edge and using negative feedback, and determines a thermal conductivity. In the method of fabricating a membrane, a thin film layer for fabricating the membrane is used as a substrate, a thin insulating layer below the thin film layer, and a substrate having a three-layer structure below the insulating layer, and the thin film layer is patterned into a membrane shape. After that, a method of manufacturing a membrane was used in which the thin insulating layer and the supporting substrate were etched from the membrane side. According to the present invention, after the thin film layer is patterned into a membrane, the thin insulating film is etched, and by using a manufacturing method of etching the support substrate, the upper thin silicon layer is not etched, and only the support substrate is etched. be able to. As a result, since the patterning of the device is all performed from the surface, there is no fear that the device is contaminated during the patterning.

According to the third aspect of the present invention, when the crystal plane of the support substrate is (100), if the direction of the membrane is arranged in parallel with the <100> direction of the support substrate, the lower part of the membrane can be efficiently supported. The substrate can be etched. In addition, when the membrane is single-crystal thin silicon, the mechanical strength is particularly higher than that of amorphous silicon, and therefore, there is an advantage that the membrane is not broken by bubbles generated when etching the support substrate. As described above, as compared with the conventional membrane production method, a membrane production method capable of producing a calorimeter by a process from one side was obtained.

According to the fourth aspect of the present invention, by using a substrate in which an etching stop layer, an etching layer, an insulating layer, and a thin film layer are laminated on a supporting substrate, if the supporting substrate is sufficiently thick, the membrane can be used. Is formed, the thickness of the substrate is almost the same as before the etching of the etching layer. As a result, the mechanical strength of the element hardly changes before and after etching, and therefore, the manufacturing method of the present invention is optimal particularly when a plurality of microcalorimeters are manufactured on the same substrate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for producing a membrane according to Embodiment 1 of the present invention.

FIG. 2 is a schematic view illustrating a method for manufacturing a membrane according to the first embodiment of the present invention.

FIG. 3 is a schematic view illustrating a method for manufacturing a membrane according to the first embodiment of the present invention.

FIG. 4 is a schematic view illustrating a method for manufacturing a membrane according to a second embodiment of the present invention.

FIG. 5 is a schematic view showing a method for producing a membrane according to Embodiment 2 of the present invention.

FIG. 6 is a schematic view showing a method for producing a membrane according to Embodiment 2 of the present invention.

FIG. 7 is a schematic view showing a method for producing a membrane according to Embodiment 2 of the present invention.

FIG. 8 is a schematic diagram showing a method for producing a membrane according to Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support substrate 2 Etching layer 3 Thin film layer 4 Resistor 5 Absorber 6 Superconducting wiring 7 Membrane 10 Support substrate 11 Insulating film 12 Thin film layer 13 Protective film 14 Hole for etching 15 Absorber 16 Resistor 17 Superconducting wiring 18 Membrane DESCRIPTION OF SYMBOLS 20 Protective film 21 Support substrate 22 Etch stop layer 23 Etching layer 24 Insulating layer 25 Thin film layer 26 Membrane 27 Resistor 28 Absorber 29 Superconducting wiring

Continued on the front page F-term (reference) 2G088 EE30 FF03 FF15 GG22 GG25 JJ04 JJ05 JJ08 JJ09 JJ23 JJ37 4M113 AC24 AC33 AD36 BC04 BC05 CA31

Claims (4)

[Claims] 1. A method for manufacturing a membrane, which is a component of a microcalorimeter that realizes high energy resolution and high-speed response by using a superconducting transition edge and using negative feedback, and that determines thermal conductivity, A membrane is formed on a substrate composed of an etching layer and a support substrate, the membrane is arranged at a distance corresponding to the thickness of the support substrate and the etching layer, and the etching layer is etched from the membrane side. A method for producing a membrane. 2. A method for manufacturing a membrane which is a component of a microcalorimeter which realizes high energy resolution and high speed response by using a superconducting transition edge and using negative feedback, wherein the method comprises the steps of: A thin film layer for producing a membrane, a thin insulating layer below the thin film layer, and a substrate having a three-layer structure including a support substrate below the insulating layer are used, and the thin film layer is patterned into a membrane shape. Etching the thin insulating layer and the supporting substrate from the side. 3. The method according to claim 2, wherein when the support substrate is silicon having a plane orientation of (100), the orientation of the membrane is arranged in parallel with <100>. 4. The method according to claim 2, wherein the substrate has an etching stop layer, an etching layer, the insulating layer, and the thin film layer laminated on a supporting substrate.