JP2002071450A - Thermal infrared detecting element and the manufacturing method, and infrared image pick-up device using the thermal infrared detecting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal infrared detecting element and the manufacturing method and an infrared image pick-up device using the thermal infrared detecting element which can prevent deterioration of the reliability of the without adding the manufacturing process. SOLUTION: The detecting element is provided with supporting legs 4.4 which support a diaphragm 3 that has a high refractive index film 42 and a second oxidated silicone film 32 on a diaphragm structure in a state where the diaphragm is separated from the semi-conductor board 2. The diaphragm 3 and the legs 4.4 have a first oxidated silicone film 31 in the lower rayer. The expansion power 8 which makes the diaphragm 3 and the legs 4.4 convex downward is added to the first oxidated silicone film 31. The expansion power 9 which hold the diaphragm 3 skelton almost parallel to the semi-conductor board 2 cancelling the expansion power 8 that makes the diaphragm 3 convex downward is added to the high refractive index film 42 of the diaphragm 3 itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal infrared detector of the bolometer type, a method of manufacturing the same, and an infrared imaging device using the thermal infrared detector, and more particularly to a method of supporting an infrared detector on a substrate. About.

[0002]

2. Description of the Related Art Conventionally, for the purpose of detecting an obstacle, detecting a human body, or monitoring at night, an image pickup apparatus equipped with an image pickup element using a far-infrared detection element which is hardly affected by disturbances such as smoke and sunlight at day and night. Camera is used.

As an image pickup device, a CCD (Charge Coup)
led devices) and photomultiplier tubes, but they do not satisfy the requirements for these applications in terms of spectral characteristics.
Further, the use of far-infrared (8 to 12 μm) as an infrared camera has higher sensitivity to blackbody radiation near normal temperature,
It is superior to CCD cameras and quantum infrared cameras that use near infrared or mid infrared.

[0004] Here, far-infrared cameras include those utilizing the quantum effect and those utilizing the thermal effect. Those using the quantum effect have good detection sensitivity, but are cooled (77
K degree) means is required.

On the other hand, a device utilizing the thermal effect is non-cooled, and is suitable for reducing the size and cost of the device. Thermal infrared detecting elements utilizing this thermal effect are classified into bolometer sensors that detect heat by changes in resistance, thermopile sensors that detect heat with thermocouples, and pyroelectric sensors that detect heat with electric charges.

With respect to the above-mentioned bolometer sensor, a thermistor-type bolometer sensor which detects heat by resistance change has recently been developed and manufactured taking advantage of the advantage that it can be monolithically formed on a silicon wafer. By the way, the sensitivity Res of the thermal infrared detecting element is expressed by the following equation (1).

Res [V / W] = η · α · VB · (1-exp (−τi / τT)) / G (1) where, η: infrared absorption coefficient α: temperature coefficient of resistance VB: Bias voltage τi: integration time τT: thermal time constant (τT = H / G) H: heat capacity G: thermal conductance

As can be seen from the equation (1), in order to improve the sensitivity of the thermal type infrared detecting element, it is necessary to use a thermal resistance change material having a large temperature coefficient of resistance α or to improve the infrared absorption η. , Or it is necessary to reduce the thermal conductance G. In addition, the responsiveness and sensitivity can be improved by reducing the heat capacity H.

Here, a general thermal infrared detecting element is:
As shown in FIG. 2, which is an explanatory view of the present invention, it usually has a diaphragm structure. That is, an infrared detector (hereinafter, referred to as a “diaphragm”) 3 separated from the semiconductor substrate 2 with a predetermined space is provided with two legs 4 as support portions.
• Supported by 4.

Inside the diaphragm 3, there are provided an insulating layer (not shown) and a thermal resistance change film whose resistance value changes with a temperature change. This thermal resistance change film is
4 is electrically connected to a circuit formed on the surface of the semiconductor substrate 2 via a wiring metal film (not shown) disposed in the semiconductor substrate 2.

In such a thermal infrared detecting element, as one method for improving the sensitivity, for example, the above-described method for reducing the thermal conductance G is adopted.

The above-described thermal conductance G is an index indicating the ease of heat flow between the diaphragm 3 and the semiconductor substrate 2, and is represented by the following equation (2).

G = N * D * W * t / l (2) where, N: number of legs, D: thermal conductivity, W: width of legs, t:
Leg thickness, l: Leg length. In order to reduce the thermal conductance G based on the equation (2), it is necessary to reduce the width W of the leg and the thickness t of the leg and increase the length l of the leg.

However, such a change reduces the structural stability of the legs 4 of the diaphragm 3. That is, by decreasing the leg width W and the leg thickness t and increasing the leg length 1, the possibility that the diaphragm 3 contacts the semiconductor substrate 2 increases. Diaphragm 3
Is in contact with the semiconductor substrate 2, heat flows through the contact portion, the thermal conductance G is significantly increased, and the sensitivity of the thermal infrared detecting element is largely deteriorated.

In order to solve such a problem, for example, in the conventional thermal infrared detecting element disclosed in Japanese Patent Application Laid-Open No. 7-225152, as shown in FIGS. The legs 110 of the diaphragm 100 are controlled by controlling the extension force of the insulating layer forming the
It has a structure that warps in a direction away from zero (hereinafter, referred to as “upward”).

[0016]

However, in the above-described conventional thermal infrared detecting element and the method of manufacturing the same, the legs 11
Usually, the same insulating layer is used for the diaphragm 110 and the diaphragm 100, so that the diaphragm 100 is deformed into a convex shape like the legs 110 and 110, and the diaphragm 100 can contact the substrate 120 by this deformation. There is.

For this reason, according to the technique disclosed in the above publication, measures are roughly divided into two methods. (1) One is as shown in FIG.
The lower first silicon oxide of the first silicon oxide film 101, the second silicon oxide film 102, the wiring metal film 103, and the third silicon oxide film 104, which are the insulating layers stacked to form 110. By providing a large extension force only to the film 101 and not providing the first silicon oxide film 101 to the diaphragm 100, the legs 110
This is a structure in which only the diaphragm 10 is warped upward while the diaphragm 100 is kept flat. (2) As shown in FIGS. 10B and 10C, the other
The extension force of the lower silicon oxide film 105 among the lower silicon oxide film 105 and the third silicon oxide film 104, which are the insulating layers constituting the diaphragms 10 and 110 and the diaphragm 100, is adjusted so that the legs 110 and 110 warp upward. In order to set and prevent deformation of the diaphragm 100, a silicon nitride film 106 (FIG. 1) is formed on the lower surface of the diaphragm 100 as a layer for canceling the extension force of the lower silicon oxide film 105.
0 (b)) or a fourth silicon oxide film 107 (FIG. 10 (c)) is formed on the upper surface of the diaphragm 100.

However, in the case of (1), the number of processing processes for processing the first silicon oxide film 101 increases, and further, the first silicon oxide films 101
When the wiring metal film 103 passes through the processing steps 108, 108, there is a high possibility that the wiring metal film 103 is disconnected, and the reliability of the element is reduced.

On the other hand, in the case of (2), the silicon nitride film 1
As shown in FIG. 10B, when the process of forming the 06 or fourth silicon oxide film 107 is increased, when the silicon nitride film 106 is provided, the wiring metal film 103 is formed similarly to (1). Processing step 10 of silicon nitride film 106
There is a possibility of disconnection when passing through 8.108.

That is, according to the technique disclosed in the above publication, the diaphragm 100 can be separated from the substrate 120 in a flat state, but a new layer is provided to maintain the diaphragm 100 in a flat state. On the other hand, there is a problem that the reliability of the element is reduced due to the presence of the processing steps 108 while increasing.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a thermal infrared detecting element capable of preventing a reduction in element reliability without increasing the number of manufacturing processes. Another object of the present invention is to provide an infrared imaging element using the thermal infrared detection element and a method of manufacturing the same.

[0022]

In order to solve the above-mentioned problems, a thermal type infrared detecting element of the present invention comprises a supporting portion for supporting an infrared detecting body having an infrared absorbing layer on a diaphragm structure separated from a substrate. In the thermal infrared detecting element provided with the infrared detector and the support having an insulating layer as a lower layer, the insulating layer is provided with a stretching force to make the infrared detector and the support convex downward. With
The infrared absorbing layer itself of the infrared detector has a counteracting force for canceling the extension force that makes the infrared detector have a downwardly convex shape and holding the infrared detector substantially parallel to the substrate. And

According to the above invention, the thermal type infrared detecting element has the support for supporting the infrared detecting body having the infrared absorbing layer on the diaphragm structure separated from the substrate.
Further, the infrared detector and the support have an insulating layer as a lower layer.

By the way, in this type of thermal infrared detecting element, it is necessary to support the infrared detecting body at a distance from the substrate in order to reduce the thermal conductance. As a result, since there is a possibility that the infrared detector may come into contact with the substrate, conventionally, the supporting portion is formed to have a downwardly convex shape by applying a stretching force to the insulating layer, while the infrared detector is It has been performed to apply a canceling force to the infrared detector to cancel the extension force so as to be held substantially parallel to the substrate.

However, in the conventional thermal-type infrared detecting element, the layer for imparting the above-described canceling force is separately provided on the infrared detecting body. Therefore, the number of manufacturing processes is increased. There has been a problem that the reliability of the device is reduced.

Therefore, according to the present invention, the insulating layer is provided with an elongation force to make the infrared detector and the support portion convex downward, and the infrared detecting layer itself of the infrared detector has the infrared detector. A canceling force is applied to cancel the elongating force that causes the body to have a downwardly convex shape and hold the infrared detector substantially parallel to the substrate.

That is, in the present invention, the infrared absorbing layer itself of the infrared detector is provided with a canceling force with respect to the stretching force applied to the insulating layer.

Therefore, since no new layer is provided, there is no increase in the number of manufacturing processes and, for example, disconnection of the metal layer due to the presence of steps, and the problem of deterioration in the reliability of the device is eliminated.

As a result, it is possible to provide a thermal type infrared detecting element which can prevent a decrease in the reliability of the element without increasing the number of manufacturing processes.

In order to solve the above-mentioned problems, the thermal type infrared detecting element of the present invention is characterized in that, in the above-mentioned thermal type infrared detecting element, the supporting portion has at least one insulating layer and one or more metal layers. I have.

According to the above invention, the support portion includes one or more insulating layers and a metal layer. For this reason, for example, in a support portion provided with a metal layer between the lower insulating layer and another insulating layer or in a support portion provided with a lower insulating layer and a metal layer, to impart an extension force to the insulating layer, A counterforce against the extension force applied to the insulating layer can be applied to the infrared absorption layer itself of the infrared detector.

Therefore, when the supporting portion includes one or more insulating layers and metal layers, a thermal infrared detecting element capable of preventing a reduction in element reliability without increasing the number of manufacturing processes is provided. can do.

In order to solve the above-mentioned problems, the thermal infrared detecting element of the present invention is the thermal infrared detecting element described above, wherein the support portion has at least one insulating layer, a metal layer, and a semiconductor layer. It is characterized by.

According to the above invention, the supporting portion includes one or more insulating layers, metal layers, and semiconductor layers. For this reason, similarly, when the supporting portion includes one or more insulating layers, metal layers, and semiconductor layers, a thermal mold capable of preventing a decrease in the reliability of the element without increasing the manufacturing process. An infrared detection element can be provided.

In order to solve the above-mentioned problems, the thermal type infrared detecting element of the present invention is characterized in that, in the above-mentioned thermal type infrared detecting element, the thickness of the infrared absorbing layer is determined by the refractive index when transmitting through the infrared absorbing layer. Is set so as to be approximately の of the wavelength in consideration of the above.

According to the above invention, the thickness of the infrared absorbing layer is set to be approximately の of the wavelength in consideration of the refractive index when transmitting through the infrared absorbing layer.

For this reason, for example, nickel chromium (NiC
r) or about 10 times as thick as a conventional infrared absorption layer using titanium nitride (TiN) or the like. As a result, the change in the elongation force due to the film thickness variation in the manufacturing process is reduced to about 1/10 of the conventional one, so that the deformation of the infrared absorbing layer due to the variation in the elongation force can be suppressed.

Further, the infrared light reflected on the surface of the infrared absorbing layer and the infrared light reflected on the metal layer cancel each other on the surface of the infrared absorbing layer, whereby the infrared light is efficiently absorbed.

In order to solve the above-mentioned problems, the thermal type infrared detecting element of the present invention is the thermal type infrared detecting element described above, wherein one or more insulating films used for the support portion are formed of a silicon oxide film. It is characterized by having.

According to the above invention, one or more insulating films used for the support portion are formed of the silicon oxide film.

Therefore, when a silicon oxide film is formed using a plasma CVD apparatus, as described later, the internal stress is adjusted by controlling the gas pressure at the time of forming the insulating film and the elongation force is controlled. Can be controlled.

As a result, for one or more insulating films, the internal stress can be easily adjusted to control the elongation force.

In order to solve the above-mentioned problems, in the thermal infrared detecting element of the present invention, in the thermal infrared detecting element described above, the infrared absorbing layer contains silicon (Si) or germanium (Ge) as a main component. It is characterized by having a membrane.

According to the above invention, the infrared absorption layer has a film containing silicon (Si) or germanium (Ge) as a main component.

Therefore, when forming the infrared absorbing layer,
As will be described later, the elongation force of the infrared absorbing layer can be controlled by controlling the power density of the RF bias applied to the substrate during film formation using a DC magnetron sputtering apparatus.

As a result, the elongation force can be controlled by easily adjusting the internal stress of the infrared absorbing layer.

In order to solve the above-mentioned problems, the method for manufacturing a thermal infrared detecting element of the present invention uses a plasma CVD apparatus with a silicon oxide film as an insulating film when manufacturing the thermal infrared detecting element described above. In addition, the elongation force is controlled by adjusting the internal stress by controlling the gas pressure during the formation of the insulating film.

According to the invention, when manufacturing a thermal infrared detecting element, an insulating film is formed of a silicon oxide film by using a plasma CVD apparatus, and a gas pressure at the time of forming the insulating film is controlled. By doing so, the internal stress is adjusted to control the elongation force.

Therefore, the elongation force can be controlled by easily adjusting the internal stress of the lower insulating film.

As a result, it is possible to provide a method of manufacturing a thermal infrared detecting element which can prevent a reduction in element reliability without increasing the number of manufacturing processes.

According to a method of manufacturing a thermal infrared detecting element of the present invention, in order to solve the above-mentioned problems, in the method of manufacturing a thermal infrared detecting element described above, the gas pressure of a reactive gas during the formation of a silicon oxide film Is controlled to 110 Pa or less.

According to the above invention, the gas pressure of the reaction gas during the formation of the silicon oxide film is controlled to 110 Pa or less.

Thus, when the insulating film is formed from a silicon oxide film using a plasma CVD apparatus, a silicon oxide film free from cracks can be formed. As a result, it is possible to provide a method for manufacturing a thermal infrared detecting element capable of improving the yield of products.

According to a method of manufacturing a thermal infrared detecting element of the present invention, in order to solve the above-mentioned problems, in the method of manufacturing a thermal infrared detecting element described above, silicon (Si) or germanium (Ge) is used as an infrared absorbing layer. Is formed by a DC magnetron sputtering apparatus, and by controlling the power density of an RF bias applied to a substrate during film formation, the elongation force of the infrared absorption layer is controlled.

According to the above invention, a film containing silicon (Si) or germanium (Ge) as a main component is formed as a infrared absorbing layer by a DC magnetron sputtering apparatus, and an RF bias applied to a substrate during film formation is formed. By controlling the power density, the extension force of the infrared absorbing layer is controlled.

As a result, it is possible to provide a method of manufacturing a thermal infrared detecting element capable of easily adjusting internal stress and controlling elongation of the infrared absorbing layer.

In order to solve the above-mentioned problems, an infrared imaging device of the present invention is characterized by using the above-mentioned thermal infrared detection device.

According to the above invention, the infrared imaging device is
The thermal infrared detecting element described above is used.

Therefore, it is possible to provide an infrared imaging device capable of preventing a decrease in device reliability without increasing the number of manufacturing processes.

[0060]

[Embodiment 1] An embodiment of the present invention will be described with reference to FIGS.
It is as follows. In this embodiment, a bolometer-type thermal infrared detecting element, a method for manufacturing the same, and an infrared imaging element using the thermal infrared detecting element will be described.

The thermal type infrared detecting element 1 of the present embodiment is
As shown in FIG. 2, it has a diaphragm structure. That is, an infrared detector (hereinafter, referred to as a “diaphragm”) 3 having a predetermined space and separated from a semiconductor substrate 2 serving as a substrate is supported by legs 4 serving as two support members. .

As shown in FIG. 3, the above-mentioned diaphragm 3 has a semiconductor on which an integrated circuit (not shown) is formed on its surface via a wiring metal film 5 as a metal layer built in the diaphragm 3 and the legs 4. It is configured to be electrically connected to the substrate 2.

The structure of the diaphragm 3 will be described in detail.

The diaphragm 3 of the present embodiment is similar to that of FIG.
As shown in FIG. 1A, a structure in which a thermal resistance change film 41 as a semiconductor layer and a wiring metal film 5 are formed on a first silicon oxide film 31 as an insulating layer patterned into a predetermined shape. ing. The first silicon oxide film 3 is formed on the upper surface of the thermal resistance change film 41 and the wiring metal film 5.
The second silicon oxide film 32 and the high-refractive-index film 42 are stacked along the first pattern.

The thermal resistance change film 41 is a film whose resistance value changes depending on its temperature, and uses an oxide film containing titanium (Ti) as a main component or an oxide film containing vanadium (V) as a main component. be able to.

The wiring metal film 5 formed on the upper surface of the thermal resistance change film 41 is electrically connected to the thermal resistance change film 41 and reflects infrared rays by 95% or more. . That is, the wiring metal film 5 has a function as an infrared reflection film. For the wiring metal film 5, a metal material such as titanium (Ti) and aluminum (Al) can be used.

On the other hand, the second silicon oxide film 32 is formed so as to cover the thermal resistance change film 41 and the wiring metal films 5.5.
And a high refractive index film 42 are laminated. Then, the second silicon oxide film 32 and the high refractive index film 42 function as the infrared absorbing layer of the present invention. Further, the second silicon oxide film 32 functions as the insulating layer of the present invention.

That is, in the thermal infrared detecting element 1 of the present embodiment, the infrared light transmitted through the high refractive index film 42 and the second silicon oxide film 32 is reflected by the wiring metal films 5, Through the silicon oxide film 32 and the high refractive index film 42. At this time, the high refractive index film 42 and the second silicon oxide film 32 absorb energy from infrared rays.

Further, in the present embodiment, the infrared rays incident on the diaphragm 3
2 and the high refractive index film 42, the wavelength changes according to the respective refractive indices.
In consideration of the refractive index of the high refractive index film 42 and the refractive index of
The thickness of the silicon oxide film 32 and the high refractive index film 42 is set to be approximately １ ／ of the center wavelength of the wavelength band to be detected (hereinafter referred to as “incident infrared wavelength”).

As a result, the infrared light reflected on the surface of the high refractive index film 42 and the infrared light reflected on the wiring metal film 5 cancel each other on the surface of the high refractive index film 42, so that the infrared light is efficiently absorbed. As a result, the temperature of the high-refractive-index film 42 and the second silicon oxide film 32 increases, so that the thermal resistance change film 41
Then, the resistance changes due to this temperature change. Therefore, the temperature according to the resistance value of the thermal resistance change film 41 can be detected by the integrated circuit (not shown) of the semiconductor substrate 2 through the wiring metal films 5 connected to the thermal resistance change film 41.

The high refractive index film 42 has a high infrared refractive index, for example, silicon (Si) or germanium (G).
e) can be used. The refractive index of silicon (Si) is 3.5, and the refractive index of germanium (Ge) is 4.
Since it is 0, the film thickness of the high refractive index film 42 when silicon (Si) is used is approximately 7000 °, and when the film is germanium (Ge), it is approximately 6000 °. Of course, as described above, the total film thickness of the second silicon oxide film 32 and the high refractive index film 42 is approximately が of the incident infrared wavelength.
Therefore, the thickness of the high refractive index film 42 may be changed according to the thickness of the second silicon oxide film 32.

Next, as shown in FIG. 1B, like the diaphragm 3, the first silicon oxide film 31 as an insulating layer is provided on the legs 4 in the thermal infrared detecting element 1.
The wiring metal film 5 and the second silicon oxide film 32 are sequentially stacked. As described above, in the present embodiment, the first silicon oxide film 31 as an insulating layer provided below the diaphragm 3 and the first silicon oxide film as an insulating layer provided below the legs 4. Although it is common to 31, it is not necessarily limited to this, and another insulating layer may be used.

Here, the first silicon oxide film 31 and the second silicon oxide film 32 are formed by plasma CVD (Chemica).
(l Vapor Deposition) method. As described later, the first silicon oxide film 31 is compared with the second silicon oxide film 32 by appropriately controlling the parameters at the time of film formation. It is set to have a large extension force.

That is, usually, when a thin film is formed on a substrate, an internal stress is generated in the thin film. When the internal stress is a compressive stress, the thin film elongates when the internal stress is removed. Conversely, when the internal stress is a tensile stress, the thin film contracts when the internal stress is removed. Therefore, as described above, in order to set the first silicon oxide film 31 to have a larger extension force than the second silicon oxide film 32, the internal stress of the first silicon oxide film 31 must be increased. The internal stress of the second silicon oxide film 32 may be set so as to reduce the compressive stress or to increase the tensile stress.

As described above, by setting the first silicon oxide film 31 to have a larger extension force than the second silicon oxide film 32, the first silicon oxide film 31 A combined stretching force 8 of the first silicon oxide film 31 and the second silicon oxide film 32 is generated, and the legs 4 are warped upward in a direction away from the semiconductor substrate 2, that is, upward.

Incidentally, in the present embodiment, as described above, the first silicon oxide film 31 and the second silicon oxide film 32 are also arranged on the diaphragm 4. For this reason, a stress that deforms the diaphragm 3 downwardly and convexly is generated by the combined elongation force 8 of the first silicon oxide film 31 and the second silicon oxide film 32, and there is a possibility that the horizontal state cannot be maintained. is there.

Therefore, in the present embodiment, as shown in FIG. 1A, the high refraction index film 42 has a combined elongation force 8 of the first silicon oxide film 31 and the second silicon oxide film 32. By applying the extension force 9 as a canceling force that cancels out, the diaphragm 3 is suppressed from being deformed convexly downward.

Here, as described above, the high refractive index film 42
The sum of the film thickness of the second silicon oxide film 32 and the film thickness of the second silicon oxide film 32 is determined when infrared light having a wavelength that is the center of the infrared wavelength band to be detected passes through the high refractive index film 42 and the second silicon oxide film 32. Is set so as to be approximately ４ of the wavelength in consideration of the refractive index.

As a result, the thickness of the high refractive index film 42 becomes approximately 6000 ° when germanium (Ge) is used, for example.
Therefore, the change in the extension force due to the variation in the film thickness is small, and the control of the extension force is easy.

That is, for example, nickel chromium (NiC
r) or about 10 times as thick as a conventional infrared absorption layer using titanium nitride (TiN) or the like. As a result, the change in the elongation force due to the film thickness variation in the manufacturing process is reduced to about 1/10 of the conventional one, so that the deformation of the infrared absorbing layer due to the variation in the elongation force can be suppressed. It will be easier.

Next, a method for controlling the extension force of the first silicon oxide film 31, the second silicon oxide film 32, and the high refractive index film 42 will be described. First, a method for controlling the extension force of a silicon oxide (SiO ₂ ) film such as the first silicon oxide film 31 and the second silicon oxide film 32 will be described.

First, tetraethoxysilane (TEO)
When a silicon oxide (SiO ₂ ) film is formed on a silicon (Si) substrate by a plasma CVD apparatus using S) and oxygen (O ₂ ) gas as a reaction gas as a source, the silicon oxide ( FIG. 4 shows the gas pressure dependence of the internal stress in the SiO ₂ ) film. Here, in the figure, the tensile stress is a positive stress and the compressive stress is a negative stress. Other film formation parameters include tetraethoxysilane (TEOS) flow rate: 15 SCCM (Stand
erd Cubic Centi Metol), oxygen (O ₂ ) gas flow rate: 12
5 SCCM, RF (Radio Frequency) power density (high-frequency power density): 0.14 W / cm ² .

As can be seen from the figure, the internal stress of the silicon oxide (SiO ₂ ) film monotonously increases with an increase in the gas pressure of oxygen (O ₂ ), and the compressive stress changes to the tensile stress around 75 Pa. Has transitioned to That is, in a silicon oxide (SiO ₂ ) film, the elongation force can be controlled by controlling the gas pressure at the time of film formation.

Incidentally, silicon oxide (SiO 2)_Two)film
When the internal stress becomes extremely large tensile stress, the film
Tend to crack. In the present embodiment
Also 10 × 10⁸(Dyn / cm^Two)
By force, silicon oxide (SiO _Two) Cracks occur in the film
Was. For this reason, silicon oxide (SiO_Two)
It is desirable that the gas pressure be set to 110 Pa or less.

Next, a method for controlling the extension force 9 of the high refractive index film 42 made of a silicon (Si) film will be described.

First, when a silicon (Si) film is formed on a silicon (Si) substrate by DC magnetron sputtering, the bias of the internal stress of the silicon (Si) film at the time of film formation is as shown in FIG. Is shown. Here, the bias is applied at a high frequency (RF) and arranged according to the power density. Other film formation parameters are as follows: target: silicon (Si), argon (Ar) pressure: 0.6
5 Pa, sputtering power density: 1.18 W / cm ² .

As can be seen from the figure, the internal stress of the silicon (Si) film monotonously decreases with an increase in the high frequency (RF) bias power density. Therefore, the high frequency (R
F) By controlling the bias, the silicon (S
i) It is possible to control the stretching force 9 of the membrane. This tendency is the same for the germanium (Ge) film, and the extension force 9 of the germanium (Ge) film can be controlled by controlling the high frequency (RF) bias.

Therefore, the thermal infrared detecting element 1 is manufactured by controlling the extension force of the first silicon oxide film 31, the second silicon oxide film 32, and the high refractive index film 42 by the above-described method. The diaphragm 3 can be flattened and a diaphragm structure supported above the semiconductor substrate 2 by the legs 4 can be realized. As a result, it is possible to stably manufacture the thermal infrared detecting element 1 having a small thermal conductance G and high sensitivity. That is, the stable separation of the thermal resistance change film 41 from the semiconductor substrate 2 prevents the diaphragm 3 from coming into contact with the semiconductor substrate 2 and improves the yield of the thermal infrared detecting element 1.

Next, a specific method for manufacturing the thermal infrared detecting element 1 will be described.

First, as shown in FIG. 6A, a coating type polyimide such as “PIQ (Hitachi Chemical / DuPont)” or the like is placed on a semiconductor substrate 2 on which an integrated circuit (not shown) is formed. A sacrificial layer 30 made of an organic coating resin such as a resist is formed.

Next, as shown in FIG. 6 (b), for example, tetraethoxysilane (TEOS) using a plasma CVD apparatus using tetraethoxysilane (TEOS) and oxygen (O ₂ ) gas as a source. Flow rate: 15 SCCM,
Oxygen (O ₂ ) gas flow rate: 125 SCCM, RF power density (high frequency power density): 0.14 W / cm ² , gas pressure: 50 Pa, and the first silicon oxide film
A film is formed with a thickness of 00 °. At this time, as shown in FIG.
The first silicon oxide film 31 has about 7 × 10 ⁸ dyn / c
m ² of compressive stress is generated.

Next, as shown in FIG. 6C, a thermal resistance change film 41 mainly composed of an oxide of titanium (Ti) or vanadium (V) is formed to a thickness of 1000.degree.
It is processed into a predetermined shape by an etching method such as a (reactive ion etching) method or an ion milling method.

Next, as shown in FIG. 6D, a wiring metal film 5 made of a metal material such as titanium (Ti) or aluminum (Al) is formed to a thickness of 500.degree. It is processed into a shape that covers almost the entire surface except for the central part. This processing includes the RIE (reactive
An etching method such as an ion etching method or an ion milling method can be used.

Next, as shown in FIG. 6 (e), for example, tetraethoxysilane (TEOS) using a plasma CVD apparatus using tetraethoxysilane (TEOS) and oxygen (O ₂ ) gas as a source. Flow rate: 15 SCCM,
Oxygen (O ₂ ) gas flow rate: 125 SCCM, RF power density (high-frequency power density): 0.14 W / cm ² , gas pressure: 75 Pa, 10
A film is formed with a thickness of 00 °. At this time, a tensile stress of about 1 × 10 ⁸ dyn / cm ² is generated in the second silicon oxide film 32.

Next, as shown in FIG. 6F, a high refractive index film 42 made of silicon (Si) is formed to a thickness of 6700 ° by using DC magnetron sputtering. At this time, a high frequency (RF) bias having a power density of 1 mW / cm ² is applied to the semiconductor substrate 2. As a result, the stretching force due to the internal stress of the first silicon oxide film 31, the second silicon oxide film 32, and the high refractive index film is canceled.

Next, as shown in FIG.
The high refractive index film 42, the first silicon oxide film 31, and the second silicon oxide film 32 are processed into a predetermined shape by a (reactive ion etching) method or an ion milling method. Further, the sacrificial layer 30 is removed by oxygen plasma or wet etching, thereby removing
The thermal infrared detecting element 1 having the cross section shown in FIG.

In the thermal infrared detecting element 1 manufactured as described above, the legs 4 are raised by the extension force 8 due to the difference in internal stress between the first silicon oxide film 31 and the second silicon oxide film 32. Thus, the diaphragm 3 could be supported upward. Further, by canceling the combined stretching force 8 of the first silicon oxide film 31 and the second silicon oxide film 32 with the stretching force 9 of the high refractive index film 42, the semiconductor substrate 2 can be flattened without deformation. A parallel diaphragm 3 could be made.

As described above, in the thermal infrared detecting element 1 of the present embodiment, the diaphragm 3 having the second silicon oxide film 32 and the high refractive index film 42 is supported by the diaphragm structure separated from the semiconductor substrate 2. Equipped with legs 4
The diaphragm 3 and the legs 4 have a common first silicon oxide film 31 as a lower layer.

By the way, this type of thermal infrared detecting element 1
Then, in order to reduce the thermal conductance G, it is necessary to support the diaphragm 3 in the vicinity of the semiconductor substrate 2 at a distance. As a result, since the diaphragm 3 may come into contact with the semiconductor substrate 2, conventionally, by applying an extension force 8 to the first silicon oxide film 31, the legs 4 are formed to have a downwardly convex shape. On the other hand, in order to hold the diaphragm 3 substantially parallel to the semiconductor substrate 2, an extension force 9 for canceling the extension force 8 has been applied to the diaphragm 3.

However, in the conventional thermal infrared detecting element, the layer for imparting the elongation force 9 is separately provided on the diaphragm 3, so that the number of manufacturing processes increases, while the presence of a step due to the newly provided layer causes the element to have a step. There is a problem that the reliability of the device is reduced.

Therefore, in the present embodiment, the first silicon oxide film 31 and the second silicon oxide film 32
An extension force 8 that causes the diaphragm 3 and the legs 4 and 4 to have a downward convex shape is applied, and the extension force 8 that causes the diaphragm 3 to have a downward convex shape is canceled by the high refractive index film 42 of the diaphragm 3. The diaphragm 3 to the semiconductor substrate 2
An extension force 9 that is held substantially in parallel with.

That is, in the present embodiment, the stretching force 9 is applied to the high refractive index film 42 of the diaphragm 3 with respect to the stretching force 8 applied to the first silicon oxide film 31.

Accordingly, since no new layer is provided, there is no increase in the number of manufacturing processes and no disconnection of the wiring metal film 5 due to the presence of a step, and the problem of a decrease in the reliability of the device is eliminated.

As a result, it is possible to provide the thermal infrared detecting element 1 which can prevent a decrease in the reliability of the element without increasing the manufacturing process.

Further, in the thermal infrared detecting element 1 of the present embodiment, the legs 4 include at least one of the first silicon oxide film 31 and the second silicon oxide film 32 and the wiring metal film 5. . Therefore, the leg 4 having the wiring metal film 5 between the first silicon oxide film 31 and the second silicon oxide film 32
In (4), the first silicon oxide film 31 and the second silicon oxide film 32 apply an elongation force 8 to
The stretching force 9 with respect to the stretching force 8 given by the silicon oxide film 31 and the second silicon oxide film 32 can be applied to the high refractive index film 42 of the diaphragm 3.

Therefore, the legs 4 are provided with one or more first legs.
In the case of including the silicon oxide film 31 and the second silicon oxide film 32 and the wiring metal film 5, the thermal infrared detecting element 1 capable of preventing a decrease in the reliability of the element without increasing the manufacturing process. Can be provided.

In the thermal infrared detecting element 1 according to the present embodiment, the second silicon oxide film 32 and the high refractive index
Is approximately １ ／ of the wavelength in consideration of the refractive index when transmitting through the second silicon oxide film 32 and the high refractive index film 42.
It is set to be.

Therefore, for example, nickel chromium (NiC
r) or about 10 times as thick as a conventional infrared absorption layer using titanium nitride (TiN) or the like. As a result, the change in the elongation force due to the film thickness variation in the manufacturing process is reduced to about 1/10 of the conventional one, so that the deformation of the second silicon oxide film 32 and the high refractive index film 42 due to the variation in the elongation force can be suppressed. .

Further, since the infrared light reflected on the surface of the high refractive index film 42 and the infrared light reflected on the wiring metal films 5 cancel each other out on the surface of the high refractive index film 42, the infrared light is efficiently absorbed. As a result, the temperature of the high refractive index film 42 and the second silicon oxide film 32 rises, so that the resistance of the thermal resistance change film 41 changes due to this temperature change. Therefore,
The temperature according to the resistance value of the thermal resistance change film 41 can be detected by an integrated circuit (not shown) of the semiconductor substrate 2 through the wiring metal films 5 connected to the thermal resistance change film 41.

In the thermal infrared detecting element 1 of the present embodiment, one or more of the first silicon oxide film 31 and the second silicon oxide film 32 used for the legs 4 are formed of a silicon oxide film. ing.

Therefore, when a silicon oxide film is formed by using a plasma CVD apparatus as described later, the first silicon oxide film 31 and the second silicon oxide film 3 are formed.
The elongation force 8 can be controlled by adjusting the internal stress by controlling the gas pressure during the film formation of No. 2.

As a result, it is possible to easily adjust the internal stress of one or more of the first silicon oxide film 31 and the second silicon oxide film 32 to control the elongation force 8.

In the thermal infrared detecting element 1 of the present embodiment, the high refractive index film 42 has a film containing silicon (Si) or germanium (Ge) as a main component. It should be noted that the fact that silicon (Si) or germanium (Ge) is the main component means that the high refractive index film 42 is made of (Si) or germanium (G).
e), or other components other than (Si) or germanium (Ge).

Therefore, when the high refractive index film 42 is formed, the power density of the RF bias applied to the substrate at the time of film formation is controlled by using a DC magnetron sputtering apparatus, as described later, so that the high refractive index film 42 can be formed. The extension force 9 of the refractive index film 42 can be controlled.

As a result, the extension stress 9 can be controlled by easily adjusting the internal stress of the high refractive index film 42.

A film containing silicon (Si) or germanium (Ge) as a main component has a high infrared refractive index. Thereby, the thickness of the infrared absorption layer can be reduced, and an increase in the heat capacity of the diaphragm 3 can be avoided.

In the method of manufacturing the thermal infrared detecting element 1 of the present embodiment, when the thermal infrared detecting element 1 is manufactured, the first silicon oxide film 31 and the second silicon oxide film 32 are The first silicon oxide film 31 is formed using a plasma CVD apparatus.
Further, the elongation force 8 is controlled by adjusting the internal stress by controlling the gas pressure when the second silicon oxide film 32 is formed.

Therefore, the extension force 8 can be controlled by easily adjusting the internal stress of the first silicon oxide film 31.

As a result, it is possible to provide a method of manufacturing the thermal infrared detecting element 1 which can prevent a decrease in the reliability of the element without increasing the number of manufacturing processes.

Further, in the method of manufacturing the thermal infrared detecting element 1 of the present embodiment, the gas pressure of oxygen (O ₂ ), which is a reaction gas at the time of forming a silicon oxide (SiO ₂ ) film, is set to 1
It is controlled to 10 Pa or less.

As a result, the first silicon oxide film 31
In addition, when the second silicon oxide film 32 is formed using a silicon oxide film by a plasma CVD apparatus, a silicon oxide film free from cracks can be formed. As a result, it is possible to provide a method of manufacturing the thermal infrared detecting element 1 that can improve the yield of products.

In the method of manufacturing the thermal infrared detecting element 1 according to the present embodiment, the high refractive index film 42 is made of silicon (S
i) or a film containing germanium (Ge) as a main component is DC
The elongation force 9 of the high-refractive-index film 42 is controlled by controlling the power density of an RF bias applied to the substrate during film formation, which is created by a magnetron sputtering apparatus.

As a result, it is possible to provide a method of manufacturing the thermal infrared detecting element 1 that can easily adjust the internal stress of the high refractive index film 42 and control the elongation force 9.

In the present embodiment, the internal stress of the wiring metal film 5 is set to around 0. However, the present invention is not limited to this, and can be set arbitrarily without departing from the concept of the present invention.

In this embodiment, the thermistor type thermal infrared detecting element using the thermal resistance change film 41 has been described. For example, a thermal infrared detecting element such as a pyroelectric type or a thermopile type, or a diode bias type. The present invention can be similarly applied and manufactured in a thermal infrared detecting element utilizing the temperature dependency of voltage and the temperature dependency of transistor characteristics.

Furthermore, in the present embodiment, the high refractive index film 4
Although silicon (Si) or germanium (Ge) having a film thickness of about 6000 ° was used for 2, by controlling the variation of the film thickness strictly, titanium nitride (TiN) or nickel chromium (NiCr) was used. A high-refractive-index film made of a metal or a metal nitride can be used.

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Further, the various features described in the first embodiment can be applied in combination with the present embodiment.

The thermal infrared detecting element 50 of the present embodiment
As shown in FIGS. 7A and 7B, the first embodiment
As in the case of the thermal infrared detecting element 1 of FIG.
Are electrically connected to a semiconductor substrate 2 having an integrated circuit (not shown) formed on the surface so as to form a predetermined space. That is, the diaphragm 53 has a configuration in which a predetermined space is formed via the wiring metal film 5 and the diaphragm 53 is electrically connected to the semiconductor substrate 2.

However, the diaphragm 53 of the present embodiment
Is the second silicon oxide film 3 in the first embodiment.
2 is omitted. Therefore, in the diaphragm 53, the thermal resistance change film 41 and the wiring metal film 5 are formed on the first silicon oxide film 31 patterned into a predetermined shape. Further, the high refractive index film 42 is directly formed on the upper surfaces of the thermal resistance change film 41 and the wiring metal film 5 along the pattern of the first silicon oxide film 31.
Are laminated.

On the other hand, a first silicon oxide film 31, a wiring metal film 5, and a second silicon oxide film 32 are sequentially laminated on the legs 4 in a predetermined shape. Therefore, the legs 4.4 are the same as those in the first embodiment.

As a result, in the present embodiment, only the high refractive index film functions as an infrared absorbing layer. Also,
As the material of each layer used in the present embodiment, the same material as that described in the first embodiment can be used.

In the present embodiment, as in the first embodiment, first silicon oxide film 3
The first and second silicon oxide films 32 are formed by the P-CVD method, and the first silicon oxide film 31 becomes the second silicon oxide film by appropriately controlling parameters at the time of film formation. It is set to have a larger extension force than the film 32.

Therefore, as shown in FIG. 7B, a combined stretching force 8 of the first silicon oxide film 31 and the second silicon oxide film 32 is generated on the leg 4, and the leg 4 It will warp in the direction away from the substrate 2, that is, upward.

On the other hand, in the thermal infrared detecting element 50 of the present embodiment, the first silicon oxide film 31 as a common insulating layer is also disposed on the diaphragm 53 as an infrared detecting element. For this reason, a stress that deforms the diaphragm 53 downwardly is generated by the extension force 58 of the first silicon oxide film 31, and there is a possibility that the flat state cannot be maintained.

Therefore, in the present embodiment, as shown in FIG. 7A, an extension force 59 for canceling the extension force 58 of the first silicon oxide film 31 is applied to the high refractive index film 42. And the diaphragm 53 is suppressed from being deformed convexly downward.

The high refractive index film 4 as an infrared absorbing layer
The film thickness of No. 2 is set to be approximately 略 of the wavelength in consideration of the refractive index when infrared light having a wavelength at the center of the infrared wavelength band to be detected passes through the high refractive index film. ing.

That is, assuming that the refractive index of the high refractive index film 42 is n, the thickness is d, and the wavelength of transmitted infrared light is λ, d = λ × ｛1 / (4 × n) ｝ ……… (3) holds.

In the present embodiment, as in the first embodiment, the internal stress of the wiring metal film 5 is set to a value close to 0. However, the present invention is not limited to this, and may be any value within a range not departing from the concept of the present invention. Can be set to

As described above, in the thermal infrared detecting element 50 of the present embodiment, the first silicon oxide film 31 is provided with the extension force 58.8 for making the diaphragm 53 and the legs 4 4 convex. And the diaphragm 53
The high-refractive-index film 42 itself cancels out the stretching force 58 that causes the diaphragm 53 to have a downwardly convex shape, and
Is applied substantially parallel to the semiconductor substrate 2.

That is, in the present embodiment, the high refractive index film 42 of the diaphragm 53 is provided with a canceling force 59 with respect to the extension force 58 applied to the first silicon oxide film 31.

Accordingly, since no new layer is provided, there is no increase in the number of manufacturing processes and no disconnection of the wiring metal film 5 due to the presence of a step, and the problem of deterioration in the reliability of the element is eliminated.

As a result, it is possible to provide the thermal infrared detecting element 50 which can prevent a decrease in the reliability of the element without increasing the manufacturing process.

In the thermal infrared detecting element 50 of the present embodiment, the thickness of the high refractive index film 42 is
The wavelength is set to be approximately １ ／ of the wavelength in consideration of the refractive index at the time of transmission of the light.

Accordingly, for example, nickel chromium (NiC
r) or about 10 times as thick as a conventional infrared absorption layer using titanium nitride (TiN) or the like. As a result, the change in the elongation force due to the film thickness variation in the manufacturing process is reduced to about 1/10 of the conventional one, so that the deformation of the high refractive index film 42 due to the variation in the extension force can be suppressed.

Further, the infrared rays reflected on the surface of the high refractive index film 42 and the infrared rays reflected on the wiring metal films 5.5 cancel each other on the surface of the high refractive index film 42, whereby the infrared rays are efficiently absorbed.

[Embodiment 3] The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.
The various features described in the first and second embodiments can be applied in combination with the present embodiment.

The thermal type infrared detecting element 60 of the present embodiment
As shown in FIGS. 8A and 8B, the first embodiment
As in the case of the thermal infrared detecting element 1 of
It is electrically connected to a semiconductor substrate 2 having an integrated circuit (not shown) formed on the surface so as to form a predetermined space. That is, the diaphragm 3 has a configuration in which a predetermined space is formed via the wiring metal film 5 and the diaphragm 3 is electrically connected to the semiconductor substrate 2.

In the diaphragm 3, a thermal resistance change film 41 as a semiconductor layer and a wiring metal film 5 are formed on a first silicon oxide film 31 patterned into a predetermined shape. Further, the second silicon oxide film 32 and the high refractive index film 4 are formed on the upper surfaces of the thermal resistance change film 41 and the wiring metal film 5 along the pattern of the first silicon oxide film 31.
2 are formed. The thermal resistance change film 41, the second silicon oxide film 32, and the high refractive index film 42 are processed into substantially the same shape as the first silicon oxide film 31.

As a result, the diaphragm 3 of the present embodiment
Are the same as in the first embodiment.

On the other hand, in the present embodiment, the legs 64
The first silicon oxide film 31, the thermal resistance change film 41, the wiring metal film 5, and the second silicon oxide film 32 are sequentially laminated in a predetermined shape. That is, the legs 64 are also provided with the thermal resistance change film 41. The formation of the thermal resistance change film 41 on the legs 64 is performed at the same time as the formation of the thermal resistance change film 41 on the diaphragm 53, and thus does not involve any increase in the manufacturing process.

In the thermal infrared detecting element 60 described above, the second silicon oxide film 32 and the high refractive index film 42 function as an infrared absorbing layer, similarly to the diaphragm 3 of the first embodiment. Further, as the material of each layer used in the present embodiment, the same material as that of the first and second embodiments can be used.

As a result, in the thermal infrared detecting element 60 of the present embodiment, the structure of the legs 64 is the same as that of the first embodiment.
And is different from the second embodiment.

In the present embodiment, the legs 64.6
The first silicon oxide film 31 and the second silicon oxide film 32 of the diaphragm 4 and the diaphragm 3 are formed by a P-CVD method, and by appropriately controlling parameters at the time of film formation, the first silicon oxide film 31 and the second silicon oxide film 32 are formed. The film 31 is set to have a larger extension force than the second silicon oxide film 32.

Accordingly, as shown in FIG. 8B, a combined extension force 68 of the first silicon oxide film 31 and the second silicon oxide film 32 is generated on the leg 64, and the legs 64 It will warp in the direction away from the substrate 2, that is, upward.

On the other hand, in the thermal infrared detecting element 60 of the present embodiment, the first silicon oxide film 3
The first and second silicon oxide films 32 are provided. For this reason, the diaphragm 3 is formed by the combined stretching force 8 of the first silicon oxide film 31 and the second silicon oxide film 32.
There is a risk that a flat state may not be maintained because a stress is generated which deforms downward.

Therefore, in the diaphragm 3 of the present embodiment, as shown in FIG. 8A, the high refractive index film 42 and the second silicon oxide film 32 are formed in the same manner as in the first embodiment.
First silicon oxide film 31 and second silicon oxide film 32
By applying the extension force 9 that cancels out the combined extension force 8 with the above, the deformation of the diaphragm 3 to be convex downward is suppressed.

The high-refractive-index film 4 as an infrared absorbing layer
The combined thickness of the second silicon oxide film 32 and the second silicon oxide film 32 is such that the infrared ray having the wavelength in the center of the detection target infrared wavelength band is refracted when the high refractive index film 42 and the second silicon oxide film 32 pass through. In consideration of the rate, the wavelength is set to be approximately ４ of the wavelength.

In this embodiment, as in the first and second embodiments, the internal stress of the wiring metal film 5 is set near 0. However, the present invention is not limited to this. It can be set arbitrarily as long as it does not deviate. Further, in the present embodiment, the example in which the second silicon oxide film 32 exists on the legs 64 has been described.
Also in the present embodiment, as described in the second embodiment, the second silicon oxide film 32 can be omitted like the diaphragm 53.

As described above, in the thermal infrared detecting element 60 according to the present embodiment, the legs 64, 64 are formed of one or more of the first silicon oxide film 31 and the second silicon oxide film 32 and the thermal resistance change film 41. And Therefore, the legs 64
In the case where one or more of the first silicon oxide film 31 and the second silicon oxide film 32 and the thermal resistance change film 41 are provided, it is possible to prevent a decrease in the reliability of the element without increasing the manufacturing process. A thermal infrared detection element 60 can be provided.

[Embodiment 4] Another embodiment of the present invention is described below with reference to FIG. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 3 are given the same reference numerals, and descriptions thereof are omitted. The various features described in the first to third embodiments can be applied in combination with the present embodiment.

The thermal infrared detecting element 70 of the present embodiment
As shown in FIGS. 9A and 9B, the second embodiment
As in the case of the thermal infrared detecting element 50 of FIG.
Are electrically connected to a semiconductor substrate 2 having an integrated circuit (not shown) formed on the surface so as to form a predetermined space. That is, the diaphragm 53 has a configuration in which a predetermined space is formed via the wiring metal film 5 and the diaphragm 53 is electrically connected to the semiconductor substrate 2.

In the diaphragm 53, the thermal resistance change film 41 and the wiring metal film 5 are formed on the first silicon oxide film 31 patterned into a predetermined shape. Further, a high refractive index film 42 is formed on the upper surface of the thermal resistance change film 41 and the wiring metal film 5 along the pattern of the first silicon oxide film 31.

That is, the diaphragm 5 of the present embodiment
3 is the same as that described in the second embodiment, and is the same as the second silicon oxide film 3 in the first embodiment.
2 is omitted.

On the other hand, in the present embodiment, only the first silicon oxide film 31 and the wiring metal film 5 are sequentially laminated on the legs 74 in a predetermined shape.

As a result, in the present embodiment, the high refractive index film functions as an infrared absorbing layer. Further, as a material of each layer used in the present embodiment, it is desirable that titanium (Ti) is used for the wiring metal film 5. Also,
As for the other materials, the same materials as those described in the first embodiment can be used.

In the present embodiment, the first silicon oxide film 31 on the legs 74 is formed by the P-CVD method, and the first silicon oxide film 31 is formed by appropriately controlling the parameters at the time of film formation. The silicon oxide film 31 is set to have a large elongation force 78 due to the compressive stress.

On the other hand, in the present embodiment, the wiring metal film 5 is formed by a vapor deposition method or the like so as to have a tensile stress. As a result, as shown in FIG. 9B, the first silicon oxide 31 expands and the wiring metal film 5 contracts,
4 warps upward in the direction away from the semiconductor substrate 2, that is, the extension force 7 that lifts the diaphragm 53 upward.
8 occurs.

On the other hand, in the thermal infrared detecting element 70 of the present embodiment, the first silicon oxide film 31 and the wiring metal film 5 are also arranged on the diaphragm 53. For this reason, a stress that deforms the diaphragm 53 downwardly and convexly is generated by the combined elongation force 78 obtained by combining the first silicon oxide film 31 and the wiring metal film 5, so that a flat state may not be maintained.

Therefore, in the present embodiment, as shown in FIG. 9A, a combined stretching force 78 obtained by combining the first silicon oxide film 31 and the wiring metal film 5 is offset by the high refractive index film. By applying the extension force 79 as a counteracting force, the diaphragm 53 is suppressed from being deformed to be convex downward.

The high refractive index film 4 as an infrared absorbing layer
The film thickness of No. 2 is set to be approximately 略 of the wavelength in consideration of the refractive index when infrared light having a wavelength at the center of the infrared wavelength band to be detected passes through the high refractive index film. ing.

In this embodiment, since the sacrificial layer 30 is removed by oxygen plasma, no problem such as disconnection occurs even if the metal wiring film 5 made of titanium (Ti) is exposed.

As described above, in the thermal infrared detecting element 70 of the present embodiment, the legs 74 are provided with only the first silicon oxide film 31 and the wiring metal film 5 which are one or more insulating layers.

For this reason, in the legs 74 provided with the first silicon oxide film 31 and the wiring metal film 5, the extension force 78 is increased by the first silicon oxide film 31 and the wiring metal film 5.
To the extension force 79 with respect to the extension force 78 given by the first silicon oxide film 31 and the wiring metal film 5.
Can be applied to the high refractive index film 42 of the diaphragm 53 itself.

Therefore, in the case where the legs 74 include the first silicon oxide film 31 and the wiring metal film 5 which are one or more insulating layers, the reliability of the element can be improved without increasing the manufacturing process. It is possible to provide the thermal infrared detecting element 70 that can prevent the drop.

In this embodiment, the legs 74
Although the structure without the heat resistance change film 41 described above is described in 74, the structure is not limited to this, and for example, a structure in which the heat resistance change film 41 is arranged on the legs 74, 74 as shown in Embodiment 3 is applied. It is possible to

[Fifth Embodiment] The following will describe another embodiment of the present invention. For convenience of explanation, members having the same functions as those shown in the drawings of the above-described first to fourth embodiments are given the same reference numerals, and descriptions thereof will be omitted. In addition, the various features described in the first to fourth embodiments can be applied in combination with the present embodiment.

In the present embodiment, the thermal infrared detecting elements 1, 50, 60 shown in the first to fourth embodiments are used.
An infrared imaging device (not shown) in which 70 were arranged in a matrix of 320 × 240 was created.

For comparison, the first to third embodiments are described.
Fourth Embodiment Thermal Infrared Detector 1, 50, 60, 7
The thermal type infrared detecting element of the conventional structure which does not use 0 is 320 ×
240 infrared imaging devices arranged in a matrix were prepared.

Thereafter, the ratio of the thermal infrared detecting element in which the diaphragm did not contact the semiconductor substrate 2 and remained in a hollow state was compared.

As a result, Embodiments 1 to 4
In the thermal type infrared detecting elements 1, 50, 60, 70 of
%, While the hollow state was maintained very stably at a rate of 97% or more, whereas in the case of the conventional structure, the semiconductor substrate 2 and the diaphragm were in contact with 97% of some thermal infrared detecting elements.

That is, in this embodiment, the yield of the thermal infrared detecting elements 1, 50, 60, and 70 was improved.

As described above, the infrared imaging device according to the present embodiment has the above-described thermal infrared detection devices 1, 50, 60,
70 is used.

[0183] Therefore, it is possible to provide an infrared imaging device capable of preventing a decrease in device reliability without increasing the number of manufacturing processes.

[0184]

As described above, in the thermal type infrared detecting element of the present invention, the insulating layer is provided with the elongation force for making the infrared detecting body and the supporting portion convex downward, and the infrared detecting element is provided with the insulating layer. The infrared absorbing layer of the body is provided with a canceling force for canceling the elongating force for making the infrared detecting body convex downward and holding the infrared detecting body substantially parallel to the substrate.

Therefore, the infrared absorbing layer of the infrared detector itself is provided with a canceling force with respect to the stretching force applied to the insulating layer.

Therefore, since no new layer is provided, there is no increase in the number of manufacturing processes, for example, there is no disconnection of the metal layer due to the presence of a step, and there is no problem of lowering the reliability of the device.

As a result, there is an effect that it is possible to provide a thermal infrared detecting element capable of preventing a decrease in element reliability without increasing the number of manufacturing processes.

As described above, the thermal infrared detecting element of the present invention is the same as the thermal infrared detecting element described above, except that the supporting portion includes one or more insulating layers and metal layers.

Therefore, in the case where the supporting portion includes one or more insulating layers and metal layers, a thermal infrared detecting element capable of preventing a reduction in element reliability without increasing the number of manufacturing processes. This has the effect that it can be provided.

As described above, the thermal infrared detecting element of the present invention is the same as the thermal infrared detecting element described above, except that the supporting portion includes one or more insulating layers, metal layers, and semiconductor layers.

Therefore, in the case where the supporting portion includes one or more insulating layers, metal layers, and semiconductor layers, a thermal infrared ray capable of preventing a decrease in device reliability without increasing the number of manufacturing processes. There is an effect that a detection element can be provided.

As described above, in the thermal infrared detecting element of the present invention, in the thermal infrared detecting element described above, the thickness of the infrared absorbing layer is determined in consideration of the refractive index when transmitting through the infrared absorbing layer. The wavelength is set to be approximately 1/4 of the wavelength.

Therefore, the change in the elongation force due to the film thickness variation in the manufacturing process is reduced to about 1/10 of the conventional one, so that there is an effect that the deformation of the infrared absorbing layer due to the variation in the elongation force can be suppressed.

In addition, the infrared ray reflected on the surface of the infrared absorbing layer and the infrared ray reflected on the metal layer cancel each other out on the surface of the infrared absorbing layer, so that the infrared ray is efficiently absorbed.

As described above, the thermal infrared detecting element of the present invention is the same as the thermal infrared detecting element described above, except that one or more insulating films used for the supporting portion are formed of a silicon oxide film. is there.

Therefore, the silicon oxide film is formed by plasma C
When the insulating film is formed using a VD device, the elongation force can be controlled by adjusting the internal stress by controlling the gas pressure when the insulating film is formed.

As a result, it is possible to easily adjust the internal stress and control the elongation of one or more insulating films.

As described above, in the thermal infrared detecting element of the present invention, in the thermal infrared detecting element described above, the infrared absorbing layer is made of silicon (Si) or germanium (Ge).
Is provided.

Therefore, when forming the infrared absorbing layer,
By using a DC magnetron sputtering apparatus to control the power density of the RF bias applied to the substrate at the time of film formation, the extension force of the infrared absorbing layer can be controlled.

As a result, it is possible to easily adjust the internal stress of the infrared absorbing layer to control the elongation force.

According to the method of manufacturing a thermal infrared detecting element of the present invention, as described above, when manufacturing the above-described thermal infrared detecting element, an insulating film is formed from a silicon oxide film using a plasma CVD apparatus. In addition, the method is a method of controlling the elongation force by adjusting the internal stress by controlling the gas pressure when the insulating film is formed.

Therefore, it is possible to easily adjust the internal stress on the lower insulating film and control the elongation force.

As a result, there is an effect that it is possible to provide a method of manufacturing a thermal infrared detecting element capable of preventing a reduction in element reliability without increasing the number of manufacturing processes.

As described above, according to the method for manufacturing a thermal infrared detecting element of the present invention, the gas pressure of a reaction gas at the time of forming a silicon oxide film is set to 110 Pa or less in the method for manufacturing a thermal infrared detecting element described above. It is a method of controlling.

[0205] Therefore, when an insulating film is formed using a silicon oxide film by a plasma CVD apparatus, a silicon oxide film free from cracks can be formed. As a result, there is an effect that it is possible to provide a method of manufacturing a thermal infrared detecting element capable of improving the yield of products.

As described above, the method of manufacturing a thermal infrared detecting element of the present invention is the same as the method of manufacturing a thermal infrared detecting element described above, except that silicon (Si) is used as the infrared absorbing layer.
Alternatively, a method of forming a film containing germanium (Ge) as a main component by a DC magnetron sputtering apparatus and controlling the power density of an RF bias applied to a substrate during film formation to control the elongation force of the infrared absorption layer. It is.

Therefore, there is an effect that it is possible to provide a method of manufacturing a thermal type infrared detecting element which can easily adjust the internal stress and control the elongation force with respect to the infrared absorbing layer.

As described above, the infrared imaging device of the present invention uses the thermal infrared detection device described above.

[0209] Therefore, it is possible to provide an infrared imaging device capable of preventing a decrease in device reliability without increasing the number of manufacturing processes.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of a thermal infrared detecting element according to the present invention, wherein FIG. 1A is an end view taken along line XX in FIG. 3, and FIG. 1B is an end view taken along line YY in FIG. It is.

FIG. 2 is a perspective view showing the thermal infrared detecting element.

FIG. 3 is a plan view showing the thermal infrared detecting element.

In [4] The plasma CVD apparatus, in the case of creating a silicon oxide (SiO ₂₎ film on a silicon (Si) substrate, the oxygen (O ₂₎ silicon dioxide created as the gas pressure of the gas (SiO ₂₎ film 6 is a graph showing a relationship between the internal stress and the internal stress.

FIG. 5 shows a relationship between a high frequency (RF) bias power density and an internal stress of the formed silicon (Si) film when a silicon (Si) film is formed on a silicon (Si) substrate by DC magnetron sputtering. It is a graph shown.

FIGS. 6A to 6G are cross-sectional views of respective steps for illustrating a method of manufacturing a thermal infrared detecting element.

7A and 7B show another embodiment of the thermal infrared detecting element according to the present invention, and FIG. 7A shows XX in FIG.
FIG. 4B is an end view taken along line YY in FIG. 3.

8 shows still another embodiment of the thermal infrared detecting element according to the present invention, in which (a) is an end view taken along line XX in FIG. 3, and (b) is a line YY in FIG. It is an end elevation.

9A and 9B show still another embodiment of the thermal infrared detecting element according to the present invention, wherein FIG. 9A is an end view taken along line XX in FIG. 3, and FIG. 9B is a line YY in FIG. It is an end elevation.

FIG. 10 is a cross-sectional view showing a conventional thermal infrared detecting element. FIG. 10 (a) shows that a first silicon oxide film provided with an elongation force is formed only on a leg to make the leg protrude downward, while a diaphragm is formed on the diaphragm. (B) applies stretching force to the lower silicon oxide film common to the legs and the diaphragm so as to make the legs and the diaphragm convex downward by not forming the first silicon oxide film. On the other hand, the diaphragm has a newly formed silicon nitride film on the lower surface for canceling the stretching force, and (c) shows a stretching force applied to the lower silicon oxide film common to the legs and the diaphragm to make the legs and the diaphragm convex downward. On the other hand, a fourth silicon oxide film for canceling the stretching force is newly formed on the upper surface of the diaphragm.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermal infrared detection element 2 Semiconductor substrate (substrate) 3 Diaphragm (infrared detector) 4 Leg (support part) 5 Wiring metal film (metal layer) 8 Stretching force 9 Stretching force (counting force) 31 First silicon oxide film (Insulating layer) 32 Second silicon oxide film (Infrared absorbing layer, insulating layer) 41 Thermal resistance change film (Semiconductor layer) 42 High refractive index film (Infrared absorbing layer) 50 Thermal infrared detecting element 53 Diaphragm (Infrared detecting body) ) 58 Extension force 59 Extension force (counting force) 60 Thermal infrared detection element 64 Leg (supporting part) 68 Extension force 70 Thermal type infrared detection element 74 Leg (supporting part) 78 Extension force 79 Extension force (counting force)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/33 H01L 27/14 K (72) Inventor Tomohisa Koda 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term in Sharp Corporation (reference) 2G065 AA04 AB02 BA12 BA14 BA34 BB24 BE08 DA20 2G066 AC13 BA09 BA55 CA02 CA08 CA20 4M118 AA08 AA10 AB01 BA05 CA15 CA35 CB14 EA01 GA10 GD15 5C024 AX06 CY47 CY49 EX21 5B0BFBA BG20

Claims (10)

[Claims] 1. A thermal infrared detecting element comprising a support for supporting an infrared detector having an infrared absorbing layer on a diaphragm structure separated from a substrate, wherein the infrared detector and the support have an insulating layer below. In the above, the insulating layer is provided with a stretching force to make the infrared detector and the support portion have a downwardly convex shape, and the infrared absorbing layer itself of the infrared detector has the infrared detector below the convex. A thermal infrared detecting element, wherein a canceling force is applied to cancel the elongating force to be shaped and hold the infrared detector substantially parallel to the substrate. 2. The thermal infrared detecting element according to claim 1, wherein the supporting portion includes one or more insulating layers and a metal layer. 3. The thermal infrared detecting element according to claim 1, wherein the support comprises at least one insulating layer, a metal layer and a semiconductor layer. 4. The infrared absorbing layer according to claim 1, wherein the thickness of the infrared absorbing layer is set to be approximately ４ of the wavelength in consideration of the refractive index when transmitting through the infrared absorbing layer. 4. The thermal infrared detecting element according to 2 or 3. 5. The thermal infrared detecting element according to claim 1, wherein one or more insulating films used for the supporting portion are formed of a silicon oxide film. 6. The thermal infrared detecting element according to claim 1, wherein the infrared absorbing layer comprises a film containing silicon (Si) or germanium (Ge) as a main component. . 7. When manufacturing the thermal infrared detecting element according to any one of claims 1 to 6, the insulating film is formed of a silicon oxide film using a plasma CVD apparatus, and the insulating film is A method for manufacturing a thermal infrared detecting element, wherein an elongation force is controlled by adjusting an internal stress by controlling a gas pressure during film formation. 8. The method for manufacturing a thermal infrared detecting element according to claim 7, wherein the gas pressure of the reaction gas at the time of forming the silicon oxide film is controlled to 110 Pa or less. 9. A film composed mainly of silicon (Si) or germanium (Ge) as an infrared absorbing layer is formed by a DC magnetron sputtering apparatus, and the power density of an RF bias applied to a substrate during film formation is controlled. 8. The method according to claim 7, wherein the extension force of the infrared absorption layer is controlled. 10. An infrared imaging device using the thermal infrared detection device according to any one of claims 1 to 6.