JP2003294523A - Infrared detector, its manufacturing method and infrared solid imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-cooling type infrared solid imaging device including an infrared detector having high detection sensitivity. <P>SOLUTION: This infrared detector for detecting the temperature change of a detection part by a detection film includes a substrate, the detection part supported by a support leg on the substrate and having the detection film mounted thereon, a first infrared absorption film and a second infrared absorption film mutually arranged approximately in parallel, and a reflecting film for reflecting an infrared ray transmitted through the first infrared absorption film and the second infrared absorption film and allowing the infrared ray to enter the first infrared absorption film and the second infrared absorption film. A first optical distance between the first infrared absorption film and the reflecting film and a second optical distance between the second infrared absorption film and the reflecting film are mutually different. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared detector, and more particularly to an uncooled infrared detector having improved infrared detection sensitivity.

[0002]

2. Description of the Related Art FIG. 16 shows "Performa" by Ishikawa et al.
nce of 320 × 240 Uncooled IRFPA with SOI Diode Dete
ctors ”SPIE Vol. 4130, p.152-p.159 (2000), is a perspective view of an infrared solid-state imaging device 400 having a conventional structure. As shown in FIG.
0 includes a silicon substrate 301. Silicon substrate 301
A detector array 302, in which a plurality of detectors 200 are arranged in a matrix, and a signal processing circuit unit 303 that processes the electric signal output by the detector 200 and outputs the processed electric signal to the outside are provided on the top. Each of the detectors 200 included in the detector array 302 and the signal processing circuit unit 303 are connected by a wiring layer (not shown).

FIG. 17 is an enlarged top view of an infrared detector 200 included in the infrared solid-state image pickup device 400 shown in FIG. For ease of explanation, the umbrella structure 310 and the silicon oxide layer 316 are shown transparently. Further, FIG. 18 is a cross-sectional view when FIG. 17 is viewed in the DD direction. As shown in FIGS. 17 and 18, the infrared detector 200 includes a support leg 305 formed on the silicon substrate 301, and a detection unit 307 held by the support leg 305 in a hollow shape on the recess 306. The detection unit 307 has
A wiring layer 304 made of, for example, aluminum and a detection film 308 made of, for example, a silicon pn junction diode are provided. The wiring layer 304 is also provided on the support leg 305, and electrically connects the signal processing circuit unit 303 and the detection film 308. As will be described later, the wiring layer 304 also serves as the reflection film 312. Further, the umbrella structure unit 310 is provided on the detection unit 307. The umbrella structure 310 is
For example, the absorption film 311 made of titanium nitride and the absorption film 31
Insulating film 3 formed of, for example, silicon oxide, which covers 1
Including 17

In the conventional infrared solid-state image pickup device 400, the infrared rays emitted by the object to be imaged are detected by the infrared detector 2.
00 enters from the side of the umbrella structure 310 and is absorbed by the absorption film 311. On the other hand, the infrared light that has passed through the absorption film 311 is reflected by the reflection film 312 below the umbrella structure portion 310, enters the absorption film 311 from the back surface, and is absorbed. Absorption film 31
1 and the reflection film 312 form a structure (hereinafter, referred to as “infrared absorbing structure”) that absorbs infrared rays with high efficiency. In such an infrared absorption structure, the infrared wavelength λ
And the optical distance L between the absorption film 311 and the reflection film 312, the relationship expressed by the following Expression 1 is established. The details of the infrared absorption structure will be described later.

[0005]       L = (m · λ) / 4 (Equation 1)

Here, m is an odd number. Explaining the optical distance L, the wavelength of light passing through a medium having a refractive index of n is 1 / n of the wavelength in vacuum. Therefore, when this light travels in the medium by the physical distance d, the same phase change as that in the distance n · d occurs. That is, the optical distance L is
n · d. Therefore, in this infrared absorption structure, the relationship represented by the following Expression 2 is established between the wavelength λ of infrared light and the physical distance d between the absorption film 311 and the reflection film 312.

[0007]       d = (m · λ) / (4 · n) (Equation 2)

Next, the principle of the infrared absorbing structure will be described with reference to FIG. In the infrared detector 200, the reflection film 312 acts as a fixed end with respect to the incident infrared light, so that the infrared light forms a standing wave with the reflection film 312 as a node. When the above Expression 1 is satisfied, the antinode of this standing wave comes to be exactly at the position of the absorption film 311.
That is, the amplitude of the infrared ray having the wavelength satisfying the expression 1 becomes maximum at the position of the absorption film 311, and is absorbed by the absorption film 311.

The reflectance R of the reflecting film 312 with respect to infrared rays
Is expressed by the following Expression 3 called the Hagen-Rubens relationship.

R = 1− (2ω / (π · σ)) ^1/2 (Formula 3) where ω is the frequency of infrared rays and σ is the electrical conductivity of the reflective film.

In the conventional infrared solid-state image pickup device 300, the specific resistance of the reflection film 312 is set to 8.3 × so that the reflectance R with respect to infrared rays having a wavelength of 10 μm becomes 0.9 or more based on the relation of the above expression 3. It is set to 10 ⁻⁶ Ω · cm or less. The material of the reflective film 312 can be arbitrarily selected from the materials satisfying the formula 3.

It is presumed that the absorption coefficient of the absorption film 311 with respect to infrared rays becomes maximum when the sheet resistance of the absorption film 311 becomes the characteristic impedance of 377Ω / □ in free space. In the conventional infrared solid-state imaging device 400, the sheet resistance of the absorption film 311 is set based on this estimation. When the refractive index n of the interlayer film between the absorption film 311 and the reflection film 312 is larger than 1, the formula 1 and the formula 2
Therefore, the physical distance d between the absorption film 311 and the reflection film 312 is smaller than the optical distance L.

Next, a method of detecting infrared rays using the infrared detector 200 will be described. Infrared solid-state imaging device 400
When the infrared rays emitted by the subject to be imaged enter the infrared detector 200 in the detector array 302, the infrared rays are absorbed by the infrared absorption structure described above, and the temperature of the detection unit 307 rises. In accordance with the temperature change, the detection unit 307
The electrical characteristics of the sensing film 308 therein change. The electrical characteristics of each detection film 308 are read by the signal processing circuit unit 303 and output to the outside to obtain a thermal image of the subject.

[0014]

However, in the infrared detector 200 included in the infrared solid-state imaging device 400, the absorption film 311 and the reflection film 3 included in the infrared absorption structure are included.
Infrared detector 2 because 12 is one layer each
The wavelength band of infrared rays that can be detected at 00 became narrower, and the absorption efficiency of infrared rays was also low. Therefore, the detection sensitivity of the infrared detector 200 cannot be increased.

Therefore, an object of the present invention is to provide an uncooled infrared solid-state image pickup device including an infrared detector whose detection sensitivity is higher than before.

[0016]

SUMMARY OF THE INVENTION The present invention is an infrared detector for detecting a temperature change of a detection part by a detection film, which is provided with a substrate and a detection film supported by supporting legs on the substrate. The detection unit, the first infrared absorption film and the second infrared absorption film arranged substantially parallel to each other, the infrared light transmitted through the first infrared absorption film and the second infrared absorption film are reflected, and the first infrared light is reflected. A first optical distance between the first infrared absorbing film and the reflecting film, and a second infrared absorbing film and the reflecting film. The second optical distance between the infrared detectors is different from each other. In such an infrared detector, the detection sensitivity of infrared rays can be increased by making the wavelength of infrared rays that can be detected into a wide band or by increasing the absorption efficiency of infrared rays of a specific wavelength.

The first optical distance is approximately 0.75 μm or more and approximately 1.25 μm or less, and the second optical distance is approximately 2.0 μm or more and approximately 3.5 μm or less. It is preferable. In such a structure, the detection sensitivity of infrared rays can be increased by making the wavelength of infrared rays that can be detected into a wide band.

Further, it is preferable that the first optical distance and the second optical distance are approximately m / 4 times (m is an odd number) times the wavelength λ of the infrared rays. With such a structure, the detection sensitivity of infrared rays can be increased by increasing the absorption efficiency of infrared rays of a specific wavelength.

Preferably, the first optical distance is approximately ¼ times the wavelength λ of the infrared ray, and the second optical distance is
It is approximately 3/4 times the wavelength λ of the infrared rays.

A dielectric film having a refractive index of about 1 or more is provided between the first infrared absorbing film and the reflecting film and / or between the second infrared absorbing film and the reflecting film. It may be. By reducing the thickness of the umbrella structure, the thermal time constant is shortened, and it is possible to shoot a fast-moving subject.

A dielectric film having a refractive index of about 1 or more may be provided between the first infrared absorbing film and the second infrared absorbing film. Similarly, by reducing the thickness of the umbrella structure, the thermal time constant is shortened, and it is possible to shoot a fast-moving subject.

The dielectric film is preferably made of a material selected from the group consisting of silicon oxide, silicon nitride, tantalum oxide, and strontium barium titanate.

The first infrared absorbing film and the second infrared absorbing film may be composed of one continuous infrared absorbing film. With a simple structure, infrared detection sensitivity can be improved.

Preferably, the first infrared absorption film and / or
Alternatively, an antireflection film (non-reflection film) is provided on the second infrared absorption film. By preventing the reflection of infrared rays, the detection sensitivity of infrared rays can be further improved.

The antireflection film includes a first antireflection film and a second antireflection film provided on the first antireflection film, and the refractive index of the second antireflection film is the first antireflection film. It is preferably approximately the square root of the refractive index of the antireflection film.

The detection film may also serve as the first infrared absorption film or the second infrared absorption film. By having such a function, the structure of the infrared detector can be simplified.

According to the present invention, the first umbrella structure portion is provided on the detecting portion and has a leg portion and a flat portion supported by the leg portion, and the first umbrella structure portion is provided on the first umbrella structure portion. A second umbrella structure having a leg portion and a flat portion supported by the leg portion;
It is also an infrared detector characterized in that the first infrared absorbing film is included in the first umbrella structure portion and the second infrared absorbing film is included in the second umbrella structure portion.

The present invention also includes an umbrella structure portion provided on the detection portion and having a leg portion and a flat portion supported by the leg portion, the first infrared absorbing film and the second infrared absorbing film. It is also an infrared detector characterized in that the film is included in the umbrella structure.

The reflection film may be arranged on the opposite side of the umbrella structure section with the detection section interposed therebetween.

Further, the present invention is an infrared detector for detecting a temperature change of a detection part by a detection film, the substrate, the detection part provided with a detection film supported by supporting legs on the substrate, A first umbrella structure part provided on the detection part and having a leg part and a flat part supported by the leg part and including a reflection film; a leg part provided on the first umbrella structure part; A second umbrella structure portion having a flat portion including an infrared absorbing film supported by a portion, and infrared rays transmitted through the infrared absorbing film are reflected by the reflecting film and enter the infrared absorbing film. It is also an infrared detector.

Preferably, the reflection film and the infrared absorption film are films which are arranged substantially parallel to each other and have substantially the same area.

Further, according to the present invention, a detector array part in which the above infrared detectors are arranged in a matrix is connected to the infrared detectors via a wiring layer, and an electric signal extracted from the infrared detectors is transmitted. It is also an infrared solid-state imaging device characterized by including a signal processing circuit section for processing.

Further, the present invention is a method of manufacturing an infrared detector for detecting a temperature change of a detection part by a detection film, which comprises a step of preparing a substrate, a wiring layer on the substrate, and a wiring layer on the wiring layer. Forming an insulating layer including the connected sensing film; forming a first sacrificial layer on the insulating layer; forming a first hole in the first sacrificial layer; Exposing, depositing a first umbrella material layer on the first sacrificial layer so as to fill the first hole, and forming a second sacrificial layer on the first umbrella material layer And a step of forming a second hole in the second sacrificial layer to expose the first umbrella material layer,
A step of depositing a second umbrella material layer on the second sacrificial layer so as to fill the hole, and removing the first sacrificial layer and the second sacrificial layer, and then providing the insulating layer on the insulating layer. Forming a first umbrella structure part made of the first umbrella structure material layer and a second umbrella structure part provided on the first umbrella structure part and made of the second umbrella part material layer; and the substrate. To form a support leg including the wiring layer, and a detection portion supported by the support leg, including the detection film, and having the first umbrella structure portion provided on the upper portion thereof. It is also a method for manufacturing an infrared detector. With this manufacturing method, it is easy to manufacture an infrared detector having an umbrella structure.

Preferably, the first umbrella structure portion and the second umbrella structure portion include an infrared absorbing film.

Preferably, the manufacturing method is characterized in that the first umbrella structure section includes a reflection film and the second umbrella structure section includes an infrared absorption film.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a perspective view of an infrared solid-state imaging device 300 according to the embodiment of the present invention. Further, FIG. 2 is a cross-sectional view of the infrared detector 100 included in the infrared solid-state imaging device 300 when viewed in the AA direction. 1 and 2, the same reference numerals as those in FIGS. 16 to 18 indicate the same or corresponding portions. In addition, the infrared detector 100 described with the umbrella structure 310 and the absorption film 311 seen through
17 is a top view (not shown) of the infrared detector 1 shown in FIG.
00 is the same as the top view.

In the infrared solid-state imaging device 300 according to the present embodiment, a plurality of infrared detectors 100 are arranged in the silicon substrate 30 as in the conventional infrared solid-state imaging device 400.
1 are arranged in a matrix on the first substrate 1 and are connected to the signal processing circuit unit 303 by the wiring layer 304. The appearance of the infrared solid-state imaging device using the infrared detector described in the following second to eighth embodiments is also substantially the same as that of the infrared solid-state imaging device 300 shown in FIG.

Infrared detector 100 according to the present embodiment
Includes a silicon substrate 301. A silicon oxide layer 316 is provided over the silicon substrate 301. A concave portion 306 is formed in the silicon substrate 301, and on the concave portion 306,
A detection unit 307, which is held in the air by the support leg 305, is provided. The support leg 305 and the detection unit 307 are formed of the silicon oxide layer 316. A wiring layer 304 made of, for example, aluminum and a detection film 308 made of, for example, a silicon pn junction diode are provided in the detection unit 307. The wiring layer 304 is also provided on the support leg 305, and electrically connects the detection film 308 and the signal processing circuit unit 303. The wiring layer 304 also serves as the reflection film 312.

Further, the umbrella structure portion 310 is provided on the detection portion 307.
Is provided. The umbrella structure portion 310 includes an absorption film 311 made of, for example, titanium nitride, and an insulating film 317 made of, for example, silicon oxide and covering the absorption film 311. The umbrella structure unit 310 is provided on the detection unit 307, and the umbrella structure unit 3 is provided.
Infrared detector 1 includes an absorption film 311.
00 has the same structure as the conventional infrared detector 200,
By providing the umbrella structure portion 310 having a two-stage structure, the infrared ray detector 200 is different from the conventional infrared detector 200 in that two absorption films 311 having different optical distances from the reflection film 312 are arranged.

Infrared detector 10 according to the present embodiment
In 0, the following two types of arrangements are possible in order to improve the infrared detection efficiency by using the two-tiered umbrella structure portion 310.

The first arrangement improves the detection efficiency of infrared rays by broadening the wavelength of infrared rays absorbed by the detection film 311 included in the umbrella structure portion 310 to a wide band. FIG. 3 is a graph showing the infrared spectral emission characteristics of a black body, where the horizontal axis is the infrared wavelength and the vertical axis is the spectral emissivity (Spectr).
al Radiant Emittance). FIG. 4 is a graph showing the transmittance of infrared rays in the atmosphere, where the horizontal axis is the wavelength of infrared rays and the vertical axis is the transmittance.

From FIG. 3, the infrared rays copied from the object at a temperature near 300 K are spread so that the maximum is around 10 μm, and the detection sensitivity of the object is improved by detecting the infrared wavelength in a wide band. Also, from FIG.
In the atmosphere where the infrared solid-state imaging device 300 is actually used, among infrared rays radiated from a subject, the wavelength is about 3 to
It can be seen that the infrared ray transmittance is high in the band of 5 μm, approximately 8 to 14 μm. Therefore, the detection sensitivity of the subject is improved by mainly detecting the infrared rays in these two bands.

That is, in the first arrangement, the infrared detector 100 of FIG.
The optical distance from the reflective film 312 to the lower absorption film 311 is in the range of approximately 0.75 μm to approximately 1.25 μm, while the optical distance from the reflective film 312 to the upper absorption film 311 is approximately 2.0 μm to approximately. The umbrella structure portion 310 having a two-stage structure may be formed so that the thickness falls within the range of 3.5 μm. As a result, it is possible to improve the absorption efficiency of infrared rays in the wavelength band of about 3 to 5 μm and infrared rays in the wavelength band of about 8 to 14 μm.

Here, on the optical path between the reflection film 312 and the absorption film 311, there are the reflection film 312, the silicon oxide layer 316 covering the absorption film 311, and the insulating film 317. Therefore, by setting the refractive index of these films to 1 or more, the physical distance (actual distance) between the reflection film 312 and the absorption film 311 becomes smaller than the optical distance, and the infrared detector 1
00 can be miniaturized.

The second arrangement is to increase the infrared ray detection efficiency by increasing the absorption rate of the infrared ray having a specific wavelength in the absorption film 311 included in the umbrella structure portion 310. That is, from the principle of the infrared absorption structure described above, for example, in the case of increasing the absorption efficiency of infrared rays having a wavelength of 10 μm, if the optical distance from the reflection film 312 to the absorption film 311 is set to approximately 2.5 μm, the absorption is performed. The absorption efficiency of the film 311 is the highest. Further, from the above formula 1, there is an optical distance at which resonance absorption occurs at each position of an odd multiple of the optical distance of about 2.5 μm. Therefore, as shown in FIG.
In the infrared detector 100 having the two-tier umbrella structure section 310, for example, the optical distance from the reflection film 312 to the lower absorption film 311 is approximately 2.5 μm, and the optical distance from the reflection film 312 to the upper absorption film 311 is reduced. If the two-tiered umbrella structure portion 310 is formed so that the distance is about 7.5 μm, the two absorption films 311 can absorb infrared rays with a wavelength of about 10 μm with high efficiency.

Also in such a structure, by disposing a film having a refractive index of 1 or more such as an insulating film 317 on the optical path between the reflection film 312 and the absorption film 311, the reflection film 312 and the absorption film 311 are separated from each other. The physical distance between them can be smaller than the optical distance. Note that when the optical path is entirely vacuum, specifically, when the silicon oxide layer 316 and the insulating film 317 are not present between the reflective film 312 and the absorption film 311, the umbrella structure portion 310 includes an insulating film and the like. It goes without saying that the physical distance and the optical distance are the same in the case where the absorption film 311 alone is used).

As described above, in the infrared solid-state image pickup device 300 including the infrared detector 100 according to the present embodiment, 2
An infrared detector having a higher infrared detection sensitivity than before by using the stepped umbrella structure portion 310 to make the wavelength of the infrared light that can be detected into a wide band or by increasing the absorption efficiency of infrared light of a specific wavelength. An infrared solid-state imaging device 300 equipped with 100 can be obtained.

In the present embodiment, the case where the umbrella structure portion 310 has two stages has been described, but the umbrella structure portion 310 can have three or more stages. When the umbrella structure portion 310 has three or more stages, it becomes possible to further increase the wavelength of infrared rays to be absorbed and to further increase the absorption efficiency of infrared rays of a specific wavelength.

Next, with reference to FIG. 5, a method of manufacturing the infrared solid-state imaging device 300 according to the present embodiment will be described. The manufacturing method includes the following steps 1 to 6.

Step 1: As shown in FIG. 5A, a silicon substrate 301 is prepared, and subsequently the silicon substrate 301 is prepared.
A silicon oxide layer 316 is deposited thereon. Further, a sensing film material is deposited on the silicon oxide layer 316 and patterned to form a sensing film 308. Detection film 30
8, for example, a bolometer material such as VO _X, consisting of silicon pn junction diode is formed.

Step 2: As shown in FIG. 5B, a silicon oxide layer 316 is further deposited so as to cover the detection film 308. Then, after forming, for example, an aluminum layer on the silicon oxide layer 316, this is patterned to form the wiring layer 304. In this step, transistors, capacitors, wiring layers, etc. are formed also in the position of the signal processing circuit unit 303 around the infrared detector 100 (see FIG. 1).
Further, the silicon oxide layer 31 is formed so as to cover the wiring layer 304.
6 is deposited.

Step 3: As shown in FIG. 5C, a predetermined position of the silicon oxide layer 316 is etched to form an etching hole 309. The silicon substrate 301 is exposed on the bottom surface of the etching hole 309. Then, the silicon oxide layer 316 is filled so as to fill the etching hole 309.
A sacrificial layer 313 is deposited on top. The sacrificial layer 313 is made of, for example, polyimide, a resist material, or polycrystalline silicon. By using these materials for the sacrificial layer 313,
The flatness of the surface of the sacrificial layer 313 is improved, and the umbrella structure portion 310
It is possible to easily realize a multilayer structure such as.

Step 4: As shown in FIG. 5D, the sacrifice layer 313 above the detection film 308 is opened. Then, an insulating film 317 is formed on the sacrificial layer 313 by plasma CVD so as to fill the opening. Insulation film 317
Is made of, for example, silicon oxide or silicon nitride. Subsequently, a titanium nitride film, for example, is deposited on the insulating layer 317 by a sputtering method, and this is patterned to form the absorbing layer 31.
1 is formed. Further, an insulating film 317 is deposited so as to cover the absorption layer 311. Finally, the insulating film 317 is patterned into a predetermined shape to form the lower umbrella structure portion 310. The above steps 1 to 4 are the infrared solid-state imaging device 4 including the infrared detector 200 having the conventional structure shown in FIGS.
The manufacturing method of No. 00 is the same.

Step 5: As shown in FIG.
The sacrificial layer 313 is deposited on the umbrella structure 310, and the upper umbrella structure 310 is formed by the same method as the above-described step 4.
The upper umbrella structure 310 is supported on the upper surface of the lower umbrella structure 310.

Step 6: As shown in FIG. 5F, an etchant such as XeF is introduced through the holes between the adjacent umbrella structure portions 310. As a result, the two sacrificial layers 313 are removed, and further a part of the silicon substrate 301 is removed. As a result, the detection unit 30 supported by the support legs 305 is provided on the recess 306 provided in the silicon substrate 301.
7 and the two-tiered umbrella structure 31 provided on the detector 307
The infrared detector 100 including 0 and 0 is completed.

In the infrared detector 100 according to this embodiment, the umbrella structure 310 may not include the insulating film 317 and may be composed of only the absorbing film 311 and the reflecting film 312.

In the manufacturing method described above, the detection film 308 is used.
Although the signal processing circuit unit 303 is formed after forming the above, the signal processing circuit unit 303 may be formed before forming the detection film 308. The former is a manufacturing method used when the sensing film 308 is made of a material compatible with a silicon process (for example, a PN junction diode formed in an SOI layer of an SOI wafer), and the latter is a manufacturing method used when the sensing film 308 is compatible with a silicon process. This is a manufacturing method used when it is made of a material (for example, a bolometer material such as vanadium oxide).

Embodiment 2. FIG. 6 is an enlarged top view of the infrared detector 110 included in the infrared solid-state imaging device 300 according to the present embodiment. For the sake of clarity, the umbrella structure 310, the absorption film 311, and the reflection film 3 are illustrated.
12 is seen through. Further, FIG. 7 is a cross-sectional view of the infrared detector 110 of FIG. 6 when viewed in the BB direction. 6 and 7, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 110 according to the present embodiment
Then, similarly to the infrared detector 100 according to the first embodiment, on the concave portion 306 provided in the silicon substrate 301,
The detection unit 307 is supported by the support legs 305. Further, a two-tiered umbrella structure section 310 is provided on the detection section 307. However, in the infrared detector 100, the detection unit 3
The reflecting film 312 (which also serves as the wiring layer 304) provided on 07 is provided on the lower umbrella structure 310, and further, in the infrared detector 100, it is provided on the two umbrella structures 310, respectively. In that the absorption film 311 that has been provided is provided only on the upper umbrella structure portion 310,
The structure is different from that of the infrared detector 100.

That is, in the infrared detector 110, the detector 3
The wiring layer 304 in 07 is left only in the connection portion with the detection film 308, and the area of the wiring layer 304 is kept to a necessary minimum. Therefore, the wiring layer 304 does not function as a reflection film, and the reflection film 312 is separately provided on the lower umbrella structure portion 310. In the infrared detector 110 included in the infrared solid-state imaging device 300 according to the present embodiment, the reflection film 312 provided on the lower umbrella structure portion 310 and the absorption film 311 provided on the upper umbrella structure portion 310. The area and size of are the same.

As a result, the amount of infrared light reflected by the reflection film 312 increases, the amount of infrared light that can be absorbed by the infrared absorbing structure increases, and the infrared detection sensitivity increases. Further, since the detection unit 307 does not include the wiring layer 304, the detection unit 30
7, the thickness of No. 7 becomes small, and the heat capacity of the detection unit 307 can be made small. As a result, the thermal time constant of the infrared detector 110 becomes smaller, and it is possible to track the movement of the object quickly.

In this embodiment, the umbrella structure section 310 is used.
Although it has a two-stage structure, it is also possible to have three or more stages. By having three or more stages, the absorption films 311 are arranged in two or more stages, and like the first embodiment, the wavelength of infrared rays to be absorbed is in a wide band, or the absorption efficiency of infrared rays of a specific wavelength is increased, Further, the infrared detection sensitivity of the infrared detector 110 can be increased.

Next, a method of manufacturing the infrared detector 110 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. The manufacturing method is substantially the same as the manufacturing method of the first embodiment except for the following points.

That is, in the above-mentioned step 2 (FIG. 5B), the wiring layer 304 in the detection portion 307 is left only in the connection portion with the detection film 308, and the area of the wiring layer 304 is minimized. . In step 4 (FIG. 5D),
A reflective film 312 made of, for example, aluminum is formed on the insulating film 317, and the lower umbrella structure portion 310 including the reflective film 312 is manufactured.

Also in this manufacturing process, the signal processing circuit portion 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. Further, the umbrella structure portion 310 may be composed of only the absorption film 311 and the reflection film 312.

Third Embodiment FIG. 8 is a cross-sectional view of the infrared detector 120 included in the infrared solid-state imaging device 300 according to the present embodiment, which is a cross-sectional view corresponding to the case when seen in the AA direction of FIG. In FIG. 8, the same symbols as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 120 according to the present embodiment
Then, the detection portion 307 is supported by the support leg 305 on the concave portion 306 provided in the silicon substrate 301. A detection film 308 connected to the wiring layer 304 is provided on the support portion 307. Further, as in the second embodiment, the area of the wiring layer 304 provided in the detection unit 307 is kept to a necessary minimum.

Above the detection unit 307, the one-tiered umbrella structure unit 31 is provided.
0 is provided. The umbrella structure portion 310 includes a reflection film 312 of one layer and an absorption film 311 of two layers in this order from the bottom. The dielectric film 3 is provided between the reflection film 312 and the absorption film 311 and between the absorption film 311 and the absorption film 311.
14 is sandwiched.

Regarding the arrangement of the reflection film 312 and the absorption film 311 of the infrared detector 120, two kinds of arrangements are possible as in the first embodiment. That is, the first arrangement is
This is an arrangement for widening the wavelength of infrared rays to be absorbed. Specifically, from the reflection film 312 to the lower absorption film 311
Optical distance to about 0.75 to about 1.25 μm,
The optical distance from the reflection film 312 to the upper absorption film 311 is set to about 2.0 to about 3.5 μm.

In the infrared detector 120, the dielectric layer 31 is provided between the reflection film 312 and the absorption film 311, and the two absorption layers 311.
4 are provided. In this case, the dielectric film 314 sandwiched between the reflective film 312 and the absorbing film 311 has a refractive index of n1 and a film thickness of d1, and the lower absorbing film 311 and the upper absorbing film 31.
When the refractive index of the dielectric film sandwiched between 1 and n is n2 and the film thickness is d2, the following equations 4 and 5 are established.

[0071]       0.75 μm <n1 · d1 <1.25 μm (Equation 4)

2.0 μm <n1 · d1 + na · da + n2 · d2 <3.5 μm (Equation 5) where na is the refractive index of the lower absorption film 311 and da is the film thickness of the lower absorption film 311.

The second arrangement is an arrangement for strongly absorbing infrared rays having a specific wavelength. Specifically, for example, when absorbing infrared rays having a wavelength of about 10 μm, the reflection film 31
The optical distance from 2 to the absorption film 311 is arranged to be approximately 2.5 μm and an odd multiple thereof. Specifically, adjustment is made so as to satisfy the following equations 6 and 7.

[0074]       n1 · d1 = 2.5 μm (Equation 6)

[0075]       n1 · d1 + na · da + n2 · d2 = 7.5 μm (Equation 7)

Here, the dielectric film 314 is, for example, Ta.
If the material has a high dielectric constant, such as ₂ O ₅ or BaSrTiO ₃ , the refractive indices n1 and n2 are large. Therefore, equation 4
~ The film thicknesses d1 and d2 satisfying Expression 7 are thinned. As a result,
The thickness of the umbrella structure 317 can be reduced, and the heat capacity of the umbrella structure 310 can be reduced.

As described above, in the infrared detector 120 according to the present embodiment, the wavelength of the infrared rays that can be detected is set to a wide band, or the absorption efficiency of the infrared rays of a specific wavelength is improved, so that the infrared rays of the infrared rays are detected. The detection sensitivity can be increased. Further, since the areas of the absorption film 311 and the reflection film 312 are about the same, and the area of the reflection film 312 is larger than that of the conventional structure, the infrared detection sensitivity is increased. Further, since the umbrella structure portion 310 has one stage and the thickness thereof is small, the heat capacity of the umbrella structure portion 310 can be reduced. Further, since the wiring layer 304 included in the detection unit 307 is minimized, the heat capacity of the detection unit 307 is also reduced. Therefore, the thermal time constant of the infrared detector becomes small, and the movement of the object can be quickly tracked.

As in the conventional structure, the structure of the wiring layer 304 also serves as the reflection film, whereby the umbrella structure portion 310 is formed.
Alternatively, the reflective film 312 may not be provided.

Next, a method of manufacturing the infrared detector 120 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. The manufacturing method is substantially the same as the manufacturing method of the first embodiment except for the following points.

That is, in the above-mentioned step 2 (FIG. 5B), the wiring layer 304 in the detection section 307 is left only at the connection portion with the detection film 308, and the area of the wiring layer 304 is minimized. . In step 4 (FIG. 5D),
The reflection film 312, the dielectric film 314, the absorption film 311, the dielectric film 314, and the absorption film 31 are formed on the sacrificial layer 318 having the holes.
1 is sequentially formed to form the umbrella structure portion 310. The umbrella structure portion 310 has only one stage, and then the infrared detector 120 is manufactured by performing the process of FIG.

In this manufacturing process, the signal processing circuit section 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. Further, the umbrella structure portion 310 may be composed of only the absorption film 311, the reflection film 312, and the dielectric film 314.

Fourth Embodiment FIG. 9 is a cross-sectional view of the infrared detector 130 included in the infrared solid-state imaging device 300 according to the present embodiment, which is a cross-sectional view corresponding to the AA direction of FIG. 1. 9, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 130 according to the present embodiment
Then, the detection portion 307 is supported by the support leg 305 on the concave portion 306 provided in the silicon substrate 301. A detection film 308 connected to the wiring layer 304 is provided on the support portion 307. Further, as in the second embodiment, the area of the wiring layer 304 provided in the detection unit 307 is kept to a necessary minimum.

Above the detection unit 307, the three-tiered umbrella structure unit 3 is provided.
10 are provided. The lower umbrella structure 310 includes a reflective film 312, and the middle umbrella structure 310 includes a second absorption film 311.
The upper umbrella structure portion 310 includes two layers of absorption films 311. The reflective film 312 and the like are covered with an insulating film 317 such as silicon oxide.

Regarding the arrangement of the reflection film 312 and the absorption film 311 of the infrared detector 130, two kinds of arrangements are possible as in the first embodiment. That is, the first arrangement is
This is an arrangement for setting the wavelength of infrared rays to be absorbed into a wide band. Specifically, the optical distance from the lower reflection film 312 to the middle absorption film 311 is about 0.75 μm to about 1.25.
The optical distance from the lower reflection film 312 to the upper absorption film 311 is about 2.0 μm to about 3.5 μm. Further, in the present embodiment, each of the absorption films 311 lowered in the middle and upper umbrella structure portions 317 has two layers, so that each wavelength band of approximately 3 to approximately 5 μm and approximately 8 to approximately 14 μm. Inside, infrared rays of two different wavelengths can be strongly absorbed.

For example, the optical distance from the lower reflecting film 312 and the middle umbrella structure 310 having the two-layer absorption film 311 whose optical distances from the lower reflecting film 312 are about 0.875 μm and about 1 μm, respectively. Are approximately 2.25 μm
And the upper umbrella structure portion 310 having the two-layer absorption film 311 having a thickness of about 2.5 μm, the wavelength is about 3.
Infrared rays of 5 μm, approximately 4 μm, approximately 9 μm, and approximately 10 μm can be strongly absorbed.

FIG. 10 shows the intensity of each infrared ray absorbed by the infrared absorbing structure of the infrared detector 130, the horizontal axis shows the infrared wavelength, and the vertical axis shows the absorption intensity. As is clear from FIG. 10, the infrared wavelengths are about 3.5 μm and about 4 μm.
m, about 9 μm, and about 10 μm, the absorption intensity of infrared rays increases, and the absorption wavelength has a certain width. That is, it can be seen that infrared rays in a wider band can be absorbed. An insulating film 317 that covers the reflection film 312 and the absorption film 311 is provided on the optical path between the reflection film 312 and the absorption film 311.
Exists. Therefore, by setting the refractive index of the insulating film 317 to 1 or more, the physical distance between these films can be made smaller than the optical distance.

The second arrangement is an arrangement for strongly absorbing infrared rays having a specific wavelength. For example, approximately 10 μm
In the case of absorbing the infrared rays of, the optical distance from the reflection film 312 to the absorption film 311 is approximately 2.
5 μm and an odd multiple thereof, so that the umbrella structure portion 310
Should be formed. Furthermore, in the present embodiment, by forming each of the absorption films 311 included in the middle and upper umbrella structures 317 in two layers, it is possible to strongly absorb infrared rays having a wide wavelength band of about 10 μm. it can.

For example, the absorption film 3 whose optical distances from the lower reflection film 312 are about 2.4 μm and about 2.6 μm, respectively.
Umbrella structure part 310 in the middle tier including 11 and reflective film 31 in the lower tier
An upper umbrella structure portion 310 including an absorption film 311 having an optical distance from 2 of about 7.2 μm and about 7.8 μm is provided. This makes it possible to strongly absorb infrared rays having wavelengths of about 9.6 μm and about 10.4 μm.

Similar to the absorption spectrum shown in FIG. 10, in this case, not only infrared rays having wavelengths of about 9.6 μm and about 10.4 μm are absorbed, but there is a peak at that wavelength and a certain constant value. Infrared rays with a wavelength in the range of are absorbed. Therefore, such an arrangement can also absorb infrared rays in a wider band. Note that also in the second arrangement, the physical distance can be made smaller than the optical distance, as in the first arrangement.

When the optical path is entirely vacuum, that is,
The insulating film 31 is formed on the reflection film 312 and in the vicinity of the absorption film 311.
7 does not exist (when the umbrella structure portion 310 does not include the insulating film 317 and is configured by only the absorption film 311),
It goes without saying that the physical distance and the optical distance are equal.

As described above, in the infrared detector 130 according to the present embodiment, the wavelength of infrared rays that can be detected is set in a wide band, or the absorption efficiency of infrared rays of a specific wavelength is improved, so that The detection sensitivity can be increased. Further, since the area and size of the absorption film 311 and the reflection film 312 are substantially the same and the area of the reflection film 312 is larger than that of the conventional structure, the infrared detection sensitivity is increased.

Further, by providing the dielectric film 314 between the absorption films 311 and 311, the umbrella structure portion 310 is provided.
The heat capacity of the infrared detector 130 can be reduced, and the thermal time constant of the infrared detector 130 can be reduced.

By providing the dielectric film 314 between the absorption film 311 and the reflection film 312, the lower and middle umbrella structure portions 310 are integrated into one umbrella structure portion 310, and the umbrella structure portion 310 is removed. It can be reduced from 3 to 2.

Although two absorption films 311 are provided in each wavelength band, each absorption film 311 may have three or more layers. In this case, more infrared rays of different wavelengths can be strongly absorbed.

In this embodiment, the umbrella structure section 310 is used.
Shows the case of a three-stage configuration, but it is also possible to have four or more stages. Further, as in the conventional structure, the wiring layer 304 may also serve as a reflective film, so that the umbrella structure 310 does not have the reflective film 312.

Next, a method of manufacturing the infrared detector 130 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. The manufacturing method is substantially the same as the manufacturing method of the first embodiment except for the following points.

That is, in the above-described step 2 (FIG. 5B), the area of the wiring layer 304 is kept to a necessary minimum by leaving the wiring layer 304 in the detection portion 307 only at the connection portion with the detection film 308. . In step 4 (FIG. 5D),
The reflection film 312 is formed on the sacrificial layer 318 having the holes, and the umbrella structure portion 310 is formed.

Following step 4, the sacrificial layer 313 is deposited again to form two absorption films 311 and the middle umbrella structure 3 is formed.
Form 10. Next, the sacrificial layer 313 is deposited again, two absorption films 311 are formed, and the upper umbrella structure portion 310 is formed.
To form. However, an insulating film 317 is formed between the two absorption films in the middle stage and between the two absorption films in the upper stage so that the sheet resistance of each absorption film 311 becomes the characteristic impedance in the free space.

Also in this manufacturing process, the signal processing circuit section 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. Further, the umbrella structure portion 310 may be composed of only the absorption film 311 and the reflection film 312.

Embodiment 5. FIG. 11 is a cross-sectional view of the infrared detector 140 included in the infrared solid-state imaging device 300 according to the present embodiment, which is a cross-sectional view corresponding to the AA direction of FIG. 1. 11, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 140 according to the present embodiment
Then, the detection portion 307 is supported by the support leg 305 on the concave portion 306 provided in the silicon substrate 301. A detection film 308 connected to the wiring layer 304 is provided on the support portion 307. Further, as in the second embodiment, the area of the wiring layer 304 provided in the detection unit 307 is kept to a necessary minimum.

Above the detection unit 307, the three-tiered umbrella structure unit 3 is provided.
10 are provided. A reflective film 312 is provided in the lower stage of the three-tier umbrella structure portion 310, an absorbing film 311 is provided in the middle stage, and an absorbing film 311 and a non-reflective film (antireflection film) 315 are provided in the upper stage. The antireflection film 315 is composed of an antireflection film lower portion 315a and an antireflection film upper portion 315b.

Regarding the arrangement of the reflection film 312 and the absorption film 311 of the infrared detector 140, two kinds of arrangements are possible as in the first embodiment. That is, the first arrangement is
The second arrangement is an arrangement for strongly absorbing an infrared ray having a specific wavelength.

Further, in the infrared detector 140 according to the present embodiment, the absorption film 3 included in the upper umbrella structure portion 310.
In the antireflection film 315 provided on the reference numeral 11, the relationship of Expression 8 is established between the refractive index na of the lower antireflection film 315a and the refractive index nb of the upper antireflection film 315b.

[0106]       na = √nb (Equation 8)

That is, when the expression 8 is satisfied, the ratio of infrared rays incident on the umbrella structure 310 from the non-reflection film upper portion 315b side to the non-reflection film lower portion 315a side without being reflected becomes the maximum. Specifically, the lower part of the non-reflection film 315a is made of silicon and the upper part of the non-reflection film 315b is made of silicon oxide, thereby substantially satisfying the relationship of Expression 8. As a result, infrared rays incident on the infrared detector 140 can be minimized from being reflected on the upper surface of the umbrella structure 310.
Can absorb infrared rays efficiently.

As described above, in the infrared detector 140 according to the present embodiment, the ratio of infrared rays incident on the umbrella structure 310 from the non-reflection film upper portion 315b side to the non-reflection film lower portion 315a side without being reflected. Can be increased. The non-reflection film 315 may be provided on the upper surface of the absorption film 311 included in the middle umbrella structure portion 310.

Further, the areas of the absorption film 311 and the reflection film 312 are about the same, and the area of the reflection film 312 becomes larger than that of the conventional one.

Further, since the wavelength of infrared rays that can be detected is wide, or the infrared rays of a specific wavelength can be strongly absorbed, the infrared ray detection sensitivity is high.

In the present embodiment, the umbrella structure 310 is used.
Although the number of steps is three, the number of steps may be two or four or more. In this case, the antireflection film 315 may be formed on each step. Further, instead of using the lower portion 315a of the non-reflection film, the material of the absorption film 311 may be selected so that the refractive index of the absorption film 311 becomes the refractive index na satisfying the relationship of Expression 8.

Further, by using the wiring layer 304 as the reflection film 312, it is not necessary to provide the reflection film 312 on the umbrella structure 310. That is, each stage of the umbrella structure portion 310 may be configured to have the absorption film 311 and the antireflection film 315.

Next, a method of manufacturing the infrared detector 140 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. The manufacturing method is substantially the same as the manufacturing method of the first embodiment except for the following points.

That is, in the above-mentioned step 2 (FIG. 5B), the area of the wiring layer 304 is kept to a necessary minimum by leaving the wiring layer 304 in the detection portion 307 only at the connection portion with the detection film 308. . In step 4 (FIG. 5D),
The reflection film 312 is formed on the sacrificial layer 318 having the holes, and the umbrella structure portion 310 is formed. Further, following step 4, the sacrificial layer 313 is deposited again, the absorption film 311 is formed, and the umbrella structure portion 310 in the middle stage is formed. Then again
A sacrificial layer 313 is deposited, an absorption film 311, a non-reflection film lower portion 315a, and a non-reflection film upper portion 315b are sequentially formed to form an upper umbrella structure portion 310. Finally, an etchant is introduced from the hole between the adjacent umbrella structure parts to remove the sacrificial layer 31.
3 layers of 3 are removed, and a part of silicon substrate 301 is removed. Thereby, the infrared detector 140 is completed.

In this manufacturing process, the signal processing circuit section 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. In addition, the umbrella structure 310 is provided with the absorption film 311, the reflection film 312, and the non-reflection film 31.
You may comprise only five.

Sixth Embodiment FIG. 12 is a cross-sectional view of the infrared detector 150 included in the infrared solid-state imaging device 300 according to the present embodiment, which is a cross-sectional view corresponding to the AA direction of FIG. 1. 12, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 150 according to the present embodiment
Then, instead of forming the concave portion in the silicon substrate 301 and forming the detection portion 307 thereon, the sacrifice layer 313 is formed on the silicon substrate 301, and the detection portion 307 supported by the support legs 305 is formed thereon. is doing. In addition, the reflective film 31
2 is provided in the silicon oxide layer 318 provided on the silicon substrate 301. Other structures are shown in Figure 2.
It is the same as the infrared detector 100 shown in FIG.

The arrangement of the reflection film 312 and the absorption film 311 of the infrared detector 150 is the same as in the first embodiment.
Two types of arrangements are possible. That is, the first arrangement is an arrangement for making the wavelength of infrared rays to be absorbed into a wide band, and the second arrangement is an arrangement for strongly absorbing infrared rays of a specific wavelength. However, in the infrared detector 150, by changing the film thickness of the sacrificial layer 313 on the silicon oxide layer 318, the reflection film 312 and the two-layer absorption film 311 and the optical film between the reflection film 312 and the detection film 308 are changed. You can adjust the distance.

As described above, the infrared detector 150 according to the present embodiment can obtain the same effect as the infrared detector 100 according to the first embodiment. In addition, although the case where the umbrella structure portion 310 has a two-stage configuration is shown in the present embodiment, it is also possible to have three or more stages.

Next, a method for manufacturing the infrared detector 150 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. The manufacturing method is substantially the same as the manufacturing method of the first embodiment except for the following points.

That is, in the above-mentioned step 1 (FIG. 5A), the reflection film 312 is formed in the silicon oxide layer 318. Then, the sacrificial layer 31 is formed on the silicon oxide layer 318.
3, a silicon oxide layer 316 is formed. Subsequently, the detection film 308 is formed on the silicon oxide layer 316. next,
After performing Steps 2 to 5 (FIGS. 5B to 5E), an etchant is introduced from the holes between the adjacent umbrella structure portions 310 to remove two sacrificial layers 313 and further to detect. Membrane 30
8 remove a portion of the sacrificial layer 313 located below. Through the above steps, the infrared detector 150 according to the present embodiment is completed.

Also in this manufacturing process, the signal processing circuit section 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. Further, the umbrella structure 310 may be composed of only the absorption film 311.

Seventh Embodiment FIG. 13 is a cross-sectional view of the infrared detector 160 included in the infrared solid-state imaging device 300 according to the present embodiment, which is a cross-sectional view corresponding to the case when seen in the AA direction in FIG. 13, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 160 according to the present embodiment
Then, the upper umbrella structure portion 310 including the absorption film 311 has a structure having irregularities. That is, the optical distance from the reflection film 312 to the absorption film 311 increases at the convex portion,
The recesses formed in stripes between the protrusions are made smaller. The other structure is the same as that of the infrared detector 110 according to the second embodiment shown in FIG. 7. In addition, on the concave portion 306 provided in the silicon substrate 301,
The detection unit 307 is supported by the support legs 305. The support portion 307 has a detection film 30 connected to the wiring layer 304.
8 are provided. Furthermore, as in the second embodiment, the area of the wiring layer 304 provided in the detection unit 307 is kept to the minimum necessary.

Here, the upper umbrella structure portion 310 including the absorption film 311 has an uneven structure and is arranged to change the optical distance from the reflection film 312 to the absorption film 311 (shape of the umbrella structure portion 310). There are two types of placement. That is, the first arrangement is an arrangement for making the wavelength of infrared rays to be absorbed into a wide band, and the second arrangement is an arrangement for strongly absorbing infrared rays of a specific wavelength.

In the first arrangement, the optical distance from the reflection film 312 to the concave portion of the absorption film 311 is about 0.75 μm to about 1.25 μm, and the reflection film 312 to the absorption film 311 is similar to the first embodiment. The optical distance to the convex portion is approximately 2.0 μm
The umbrella structure 310 may be formed to have a thickness of about 3.5 μm. In the second arrangement, for example, when infrared rays of about 10 μm are absorbed, the optical distance from the reflection film 312 to the concave portion of the absorption film 311 is about 2.5 μm, and the optical distance from the reflection film 312 to the convex portion of the absorption film 311 is equal to the optical distance. The umbrella structure portion 310 may be formed so that the distance is approximately 7.5 μm.

Since an insulating film 317 that covers the reflection film 312 and the absorption film 311 exists on the optical path between the reflection film 312 and the absorption film 311, it is possible to control the physical properties by increasing the refractive index of these to 1 or more. The optical distance is smaller than the optical distance. When the optical path is entirely vacuum, that is, the reflection film 312
When the insulating film 317 does not exist on the top and in the vicinity of the absorption film 311 (the umbrella structure portion 310 does not include the insulating film 317, etc.,
It is needless to say that the physical distance and the optical distance are the same in the case where it is composed of only the absorption film 311).

Infrared detector 160 according to the present embodiment
Then, the same effect as that of the infrared detector 100 according to the first embodiment can be obtained, but in particular, in order to improve the detection sensitivity by absorbing infrared rays of two kinds of wavelengths by the above-mentioned first arrangement. Are suitable. In addition, although the case where the umbrella structure portion 310 has a two-stage configuration is shown in the present embodiment, it is also possible to have three or more stages. Further, instead of making the umbrella structure portion 310 including the absorbing film 311 uneven, the umbrella structure portion 310 including the reflection film 312 may be uneven. Further, the umbrella structure 310 itself may be provided with unevenness so as to have three or more horizontal portions, and furthermore, the upper structure is a flat umbrella structure and is fixed with respect to the lower structure. You may arrange | position so that it may have the inclination. Furthermore, by using the wiring layer 304 as the reflection film 312, the reflection film 312 does not have to be provided on the umbrella structure portion 310. That is, the detection unit 307
A structure in which only one step of the umbrella structure portion 310 having the uneven structure may be provided on the above.

Next, a method for manufacturing the infrared detector 160 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. This manufacturing method is substantially the same as the manufacturing method of the second embodiment except for the following points.

That is, after the lower umbrella structure portion 310 including the reflection film 312 is formed in the above-mentioned step 4 (FIG. 5D),
In step 5 (FIG. 5E), the sacrificial layer 313 is deposited again. Subsequently, the sacrificial layer 313 is patterned to form stripe-shaped recesses arranged substantially in parallel. After opening the sacrifice layer 313 at a predetermined position, the umbrella structure portion 310 including the absorption film 311 is formed. That is, by forming the umbrella structure portion 310 on the sacrificial layer 311 having an uneven surface, the umbrella structure portion 310 has an uneven structure. Finally,
Two sacrificial layers 313 are removed by introducing an etchant through the holes between the adjacent umbrella structure portions 310. Through the above steps, the infrared detector 160 according to this embodiment is completed.

Also in this manufacturing process, the signal processing circuit section 303 may be formed before the detection film 308 is formed, as in the manufacturing method of the first embodiment. Further, the umbrella structure portion 310 may be formed only by the reflection film 312 and the absorption film 311.

Eighth Embodiment FIG. 14 is an enlarged top view of the infrared detector 170 included in the infrared solid-state imaging device 300 according to the present embodiment. For the sake of clarity, the umbrella structure 310 and the absorption film 311 are seen through. I am doing it. Further, FIG. 15 shows the infrared detector 1 of FIG.
FIG. 70 is a cross-sectional view when 70 is viewed in the CC direction. Figure 1
4 and 15, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions.

Infrared detector 170 according to the present embodiment
Then, similarly to the infrared detector 150 according to the sixth embodiment, the sacrifice layer 313 is formed on the silicon substrate 301, and the detection portion 307 supported by the support leg 305 is formed thereon. The reflective film 312 is provided in the silicon oxide layer 318 provided on the silicon substrate 301.

However, the infrared detector 15 of the sixth embodiment
Unlike 0, the umbrella structure part 310 on the detection part 307 has a single stage, and the detection film 308 also has the function of an absorption film. That is, each of the detection unit 307 and the umbrella structure unit 310 is provided with the detection film 308 having a function of an absorption film, and the optical distances from the reflection film 312 to these two detection films 308 are different. It is arranged. Further, these two layers of detection films 308 are electrically connected in series.

Regarding the disposition of these two layers of detection film 308, two kinds of dispositions are possible as in the first embodiment and the like. That is, the first arrangement is an arrangement for making the wavelength of infrared rays to be absorbed into a wide band, and the second arrangement is an arrangement for strongly absorbing infrared rays of a specific wavelength. However, by changing the film thickness of the sacrificial layer 313 provided between the reflective film 312 and the silicon oxide layer 316, the reflective film 312 is changed.
The optical distance of the two-layer detection film (absorption film) 308 can be adjusted.

Also in the infrared detector 170, the detecting section 3
The area of the wiring layer 304 provided in 07 is minimized. That is, the wiring layer 304 in the detection unit 307
Are left only in the connection portion with the detection film 308.

As described above, in the infrared detector 170 included in the infrared solid-state image pickup device 300 according to the present embodiment, the detectable infrared wavelength is set in a wide band or the infrared absorption efficiency of a specific wavelength. It is possible to increase the infrared detection sensitivity by improving Further, since the two detection films 308 are connected in series, the change in the electric characteristics of the detection film 308 with respect to the temperature change is almost doubled, and the area of the reflection film 312 is also increased. Therefore, it is possible to provide a detector having higher infrared detection sensitivity than the conventional structure.

In the present embodiment, the umbrella structure 310 is used.
Although it has a two-stage structure, it is possible to further improve the infrared detection sensitivity by providing three or more stages.

Next, a method for manufacturing the infrared detector 170 included in the infrared solid-state imaging device 300 according to this embodiment will be briefly described. Similar to the infrared detector 150 according to the sixth embodiment, the reflective film 3 is formed in the silicon oxide layer.
After forming 12, the sacrificial layer 31 is formed on the silicon oxide layer.
3. A silicon oxide layer 316 is formed, and a detection film 308 is further formed on the silicon oxide layer 316. Next, at the position of the signal processing circuit unit 303, the transistor and the wiring layer 30 are provided.
4 is formed, but at the same time, the wiring layer 304 of the infrared detector 170 is also formed. Next, an etching hole 309 is opened at a predetermined position of the silicon oxide layer 316, and a sacrifice layer 313 is deposited. Then, the detection film 308 is formed at a predetermined position of the sacrifice layer 313 so that the detection film 308 and the wiring layer 304 in the detection unit 307 can be electrically connected, and the umbrella structure portion 310 is formed. . Finally, the adjacent umbrella structure 31
The sacrificial layer 3 is introduced by introducing an etchant through the holes between 0.
13 of the sacrificial layer 313 under the sensing film 308 by removing two layers of
Remove part of. Through the above steps, the infrared detector 170 according to the present embodiment is completed.

Although the infrared detector has been described in the first to eighth embodiments, the detector can also be used as a temperature sensor such as a humidity sensor, a flow sensor and a thermal analysis sensor. Further, the invention can be applied not only to a detector array using a plurality of detectors but also to only one detector.

[0141]

As is apparent from the above description, in the infrared detector according to the present invention and the infrared solid-state imaging device including the infrared detector, the detectable infrared wavelength is set to a wide band or specified. The infrared detection sensitivity can be increased by increasing the absorption efficiency of infrared rays of the wavelength.

Further, according to the manufacturing method of the present invention, it becomes easy to manufacture an infrared detector having an umbrella structure.

[Brief description of drawings]

FIG. 1 is a perspective view of an infrared solid-state imaging device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the infrared detector according to the first embodiment of the present invention.

FIG. 3 is a graph showing infrared spectral emission characteristics of a black body.

FIG. 4 is a graph showing infrared transmission characteristics of the atmosphere.

FIG. 5 is a cross-sectional view of the manufacturing process of the infrared detector according to the first embodiment of the present invention.

FIG. 6 is a top view of the infrared detector according to the second embodiment of the present invention.

FIG. 7 is a sectional view of an infrared detector according to a second embodiment of the present invention.

FIG. 8 is a sectional view of an infrared detector according to a third embodiment of the present invention.

FIG. 9 is a sectional view of an infrared detector according to a fourth embodiment of the present invention.

FIG. 10 is a graph showing the relationship between infrared wavelength and absorption intensity.

FIG. 11 is a sectional view of an infrared detector according to a fifth embodiment of the present invention.

FIG. 12 is a sectional view of an infrared detector according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view of an infrared detector according to a seventh embodiment of the present invention.

FIG. 14 is a top view of an infrared detector according to an eighth embodiment of the present invention.

FIG. 15 is a sectional view of an infrared detector according to an eighth embodiment of the present invention.

FIG. 16 is a perspective view of a conventional infrared solid-state imaging device.

FIG. 17 is a top view of a conventional infrared detector.

FIG. 18 is a sectional view of a conventional infrared detector.

FIG. 19 is a diagram illustrating the principle of an infrared absorption structure.

[Explanation of symbols]

100 infrared detector, 300 infrared solid-state imaging device,
301 silicon substrate, 302 detector array, 303
Signal processing circuit unit, 304 wiring layer, 305 support leg, 3
06 recessed portion, 307 detection portion, 308 detection film, 309
Etching hole, 310 umbrella structure, 311 absorption film,
312 reflective film, 313 sacrificial layer, 314 dielectric film,
315a Antireflection film lower part, 315b Antireflection film upper part.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // G01J 5/02 G01J 5/48 F 5/48 H01L 27/14 K F term (reference) 2G065 AA11 AB02 BA12 BA34 BB24 BB50 BC02 BC07 BE08 DA20 2G066 BA09 BA55 BA60 CA02 4M118 AA01 AB01 BA30 CA03 CA14 CA20 CA40 CB13 CB14 EA04 EA20 GA10

Claims (20)

[Claims] 1. An infrared detector for detecting a temperature change of a detection part by a detection film, wherein the substrate and the detection part supported by the supporting legs on the substrate and provided with the detection film are substantially parallel to each other. First infrared absorbing film and second disposed
Infrared absorbing film, infrared rays transmitted through the first infrared absorbing film and the second infrared absorbing film are reflected, and the first infrared absorbing film and the second infrared absorbing film are reflected.
A first optical distance between the first infrared absorbing film and the reflecting film, and a second optical distance between the second infrared absorbing film and the reflecting film. An infrared detector characterized in that and are different from each other. 2. The first optical distance is in the range of approximately 0.75 μm or more and approximately 1.25 μm or less, and the second optical distance is in the range of approximately 2.0 μm or more and approximately 3.5 μm or less. The infrared detector according to claim 1, wherein: 3. The infrared ray according to claim 1, wherein the first optical distance and the second optical distance are approximately m / 4 times (m is an odd number) times the wavelength λ of the infrared ray. Detector. 4. The first optical distance is approximately ¼ times the wavelength λ of the infrared light, and the second optical distance is approximately 3/4 times the wavelength λ of the infrared light. The infrared detector according to claim 1. 5. A dielectric film having a refractive index of about 1 or more is provided between the first infrared absorbing film and the reflecting film and / or between the second infrared absorbing film and the reflecting film. The infrared detector according to claim 1, wherein: 6. The infrared detector according to claim 1, wherein a dielectric film having a refractive index of about 1 or more is provided between the first infrared absorption film and the second infrared absorption film. . 7. The infrared detection device according to claim 5, wherein the dielectric film is made of a material selected from the group consisting of silicon oxide, silicon nitride, tantalum oxide, and barium strontium titanate. vessel. 8. The infrared detector according to claim 1, wherein the first infrared absorbing film and the second infrared absorbing film are one continuous infrared absorbing film. 9. The infrared detector according to claim 1, wherein an antireflection film is provided on the first infrared absorption film and / or the second infrared absorption film. 10. The antireflection film includes a first antireflection film and a second antireflection film provided on the first antireflection film, and a refractive index of the second antireflection film is 10. The substantially square root of the refractive index of the first antireflection film.
Infrared detector described in. 11. The infrared detector according to claim 1, wherein the detection film also serves as the first infrared absorption film or the second infrared absorption film. 12. A first umbrella structure section provided on the detection section, the leg section and a flat section supported by the leg section, and the leg section and the leg section provided on the first umbrella structure section. A second umbrella structure having a flat portion supported by legs, the first infrared absorption film being included in the first umbrella structure, and the second infrared absorption film being the second umbrella structure. The infrared detector according to claim 1, wherein the infrared detector is included in: 13. An umbrella structure part provided on the detection part and having a leg part and a flat part supported by the leg part, wherein the first infrared absorption film and the second infrared absorption film are The infrared detector according to claim 1, wherein the infrared detector is included in the umbrella structure portion. 14. The reflection film sandwiches the detection unit,
The infrared detector according to claim 12, wherein the infrared detector is arranged on the side opposite to the umbrella structure portion. 15. An infrared detector for detecting a temperature change of a detection part by a detection film, comprising: a substrate, a detection part supported by supporting legs on the substrate and provided with a detection film, and the detection part. A first umbrella structure part provided on the first umbrella structure part, the first umbrella structure part having a leg part and a flat part supported by the leg part and including a reflecting film; and the leg part and the first umbrella structure part provided on the first umbrella structure part. A second umbrella structure portion having a flat portion including a supported infrared absorbing film, wherein the infrared light transmitted through the infrared absorbing film is reflected by the reflecting film and enters the infrared absorbing film. Infrared detector. 16. The infrared detector according to claim 15, wherein the reflection film and the infrared absorption film are films that are arranged in parallel and face each other and have substantially the same area. 17. A detector array section in which infrared detectors selected from claims 1 to 16 are arranged in a matrix,
An infrared solid-state imaging device comprising: a signal processing circuit unit that is connected to the infrared detector via a wiring layer and processes an electric signal extracted from the infrared detector. 18. A method of manufacturing an infrared detector for detecting a temperature change of a detection part with a detection film, the method comprising: a step of preparing a substrate; a wiring layer on the substrate; and a detection connected to the wiring layer. A step of forming an insulating layer including a film, a step of forming a first sacrificial layer on the insulating layer, a step of forming a first hole in the first sacrificial layer, and exposing the insulating layer. A first layer on the first sacrificial layer so as to fill the first hole;
Depositing an umbrella material layer, forming a second sacrificial layer on the first umbrella material layer, forming second holes in the second sacrificial layer, and forming the first umbrella material layer And exposing the second sacrificial layer so as to fill the second hole.
Depositing an umbrella material layer, removing the first sacrificial layer and the second sacrificial layer, and providing a first umbrella structure portion formed on the insulating layer and comprising the first umbrella material layer;
A step of forming a second umbrella structure portion provided on the first umbrella structure portion and made of the second umbrella material layer; a supporting leg including the wiring layer by etching the substrate; and a supporting leg. And a detection part including the detection film and having the first umbrella structure part provided on the top thereof, the manufacturing method of an infrared detector. 19. The manufacturing method according to claim 18, wherein the first umbrella structure portion and the second umbrella structure portion include an infrared absorbing film. 20. The manufacturing method according to claim 18, wherein the first umbrella structure includes a reflective film, and the second umbrella structure includes an infrared absorbing film.