JPH03199933A - Infrared-ray sensor - Google Patents

Abstract

PURPOSE:To realize a compact sensor at a low cost by providing a unitary structure for an infrared-ray sensor element and a window member by using a semiconductor process. CONSTITUTION:A semiconductor substrate 11 is provided on a metallic supporting member 10. An infrared-ray sensor element 12 is formed on the surface of the substrate 11. A window member 14 having a cavity part 13 is provided so as to cover the element 12. The element 12 is constituted of a temperature sensitive part 12a and a bridge part 12b. The escape of the heat to the member 10 through the substrate 11 is prevented with the bridge part 12b. The window member 14 is constituted of an infrared-ray input part 18 and a supporting part 19. The infrared rays from the outside is guided to the element 12. The bottom part of the window member 14 is bonded to the substrate 11. The cavity part 13 is held in the vacuum state. The leakage of the vacuum degree is detected with the deformation of a diffused resistor 17 which is formed on the surface of the infrared-ray input part 18. A reinforcing part 23 is provided at the input part 18. In this structure, the window member 14 and the element 12 are finely machined by the semiconductor process, respectively. A metal cap as a window member is not required, and the package can be made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an infrared sensor suitable for use in a thermometer that measures temperature such as body temperature in a non-contact manner.

[Prior Art] Generally, infrared sensors have been used as non-contact thermometers to measure the temperature of high-temperature objects, moving objects, and substances with small heat capacity (so that their temperature changes when they come in contact with them. Examples) To explain this, they are used to measure the temperature of blast furnaces at steel mills, fire alarms as sensors for disaster prevention and safety equipment, and sensors for security that distinguish between animal body temperature and human body temperature. Recently, infrared sensors have been used in large quantities to control the temperature of household microwave ovens and refrigerators.

Since these sensors measure the temperature of a distant site from a fixed location, there are no major problems even if the measurement accuracy is poor or the measurement time is long.

On the other hand, thermometers, particularly thermometers, used in medical equipment are desirably capable of accurate measurement (17,100° C.), fast measurement (3 seconds or less), and inexpensive.

However, conventional electronic thermometers are so-called backup thermometers that estimate the temperature in a state of thermal equilibrium from the actual measurement value and the elapsed time. In addition, current body temperature measurements are mostly under the armpits or under the tongue, and seriously ill people who have lost their physical strength or the elderly are unable to hold the thermometer during temperature measurement. There were many problems.

By the way, body temperature has traditionally been measured under the armpits or under the tongue, but from a physiological background, it is not thought that the body temperature in the armpits represents the body temperature as a whole. The most accurate method is to measure core temperature, such as the temperature of the brain, which maintains a stable temperature during surgery, and is necessary for measuring body temperature during surgery. Considering these things, the temperature of the eardrum in the ear reflects the temperature of the hypothalamus, and since the auditory canal is narrow, it is also affected by the wind and infrared rays from the outside air (so the optimal temperature measurement site is I can say that.

In addition, non-contact thermometers need to detect minute amounts of infrared rays emitted from objects that have almost no difference in temperature from the outside air, such as body temperature (15 to 50 degrees Celsius), no matter how sensitive or accurate the thermometer is. If it comes into contact with even the slightest amount of air, it will be affected by wind and heat convection, making accurate temperature measurement impossible.

In order to reduce the effects of such disturbances, it is necessary to protect the infrared sensor by putting it in a package, and this package also has a window material that guides the infrared rays emitted from the object to the infrared sensor without loss. This is an important issue to consider.

Conventionally, infrared sensors for such non-contact thermometers have been made by covering a metal stem with an infrared sensor element attached to a metal cap member, and a window made of silicon or other material with a window in a part of the cap member. The structure was made of boards pasted together.

[Problems to be Solved by the Invention] However, since the above-mentioned conventional infrared sensor has a structure in which a metal cap member covers a metal stem,
The sealing part requires a flange, which increases the external size and increases the price, making it unsuitable for the above-mentioned in-the-ear thermometer.

Also, when the temperature is as low as body temperature, the infrared wavelength becomes longer wavelength (
8 to 12 μm) is the peak. Therefore, the window material is required to be a material that allows long wavelengths to pass through, has a low reflectance, has strong mechanical strength, emits little infrared radiation from the window material itself, and has excellent workability. Further, in order to prevent noise from being generated due to thermal convection of the gas inside the window material, it is desirable to keep the inside of the window material in a vacuum state. For this reason, window materials are required to have good airtightness, but conventional infrared sensor cap members have been insufficient.

The present invention has been made in view of such problems, and includes:
It can be miniaturized, has a fast measurement speed, has excellent confidentiality, and has low noise. The present invention aims to provide an infrared sensor suitable for use in thermometers and the like.

[Means for Solving the Problems] In order to solve the above conventional problems, an infrared sensor according to the present invention includes a support member, a semiconductor substrate supported on the support member, and a semiconductor substrate formed on the surface of the semiconductor substrate. an infrared sensor element that detects infrared rays and outputs an electrical signal according to the detected amount of the infrared rays; an infrared sensor element that has an infrared input section and a cavity corresponding to the infrared input section, and inputs via the infrared input section; and a window material that guides the infrared rays to the infrared sensor element, the infrared input section is deformable according to the internal pressure of the cavity, and the infrared input section has at least one corner of the bottom surface of the infrared input section. It is characterized in that a reinforcing portion is provided in a portion.

Specifically, the reinforcing portion is a curved surface portion continuously formed in a curved state from the side wall of the cavity portion to the bottom surface of the infrared input portion, particularly a curved surface portion having a constant curvature, or a curved surface portion that is continuously formed in a curved state from the side wall of the cavity portion to the bottom surface of the infrared input portion, or a curved surface portion that is continuously formed from the side wall of the cavity portion to the bottom surface of the infrared input portion. This is a sloped part that is continuously formed in a straight line across the bottom surface of the part.

Further, in the infrared sensor according to the present invention, it is preferable that the window material is formed of a semiconductor substrate, particularly a silicon substrate manufactured by a floating zone method, and it is further preferable that the cavity part is set to a negative pressure state.

[Function] In the infrared sensor configured as described above, infrared rays emitted from the object to be measured are introduced into the cavity section through the infrared input section of the window material, and are incident on the infrared sensor element. The infrared sensor element converts the signal into an electrical signal and outputs it to obtain a measured value.

This infrared sensor has a structure that integrates an infrared sensor element manufactured by microfabrication in a semiconductor process and a window material, and does not require a metal cap like conventional infrared sensors, so the flange of the stem This eliminates the need for the window material, making it possible to significantly downsize the window.Furthermore, if the window material is manufactured using a semiconductor microfabrication process, it becomes even more compact.Since it is manufactured using a patch system, the yield is high and stable, and it can be produced in large quantities at low cost. I can build it. Further, since a reinforcing portion such as a curved surface portion or an inclined portion is provided at the corner of the bottom surface of the infrared input portion, the mechanical strength of the infrared input portion is increased. As a result, the film thickness of the infrared input section can be made considerably thinner (about 20 μm), and the transmission efficiency of infrared rays can be improved.

In addition, by forming the window material using a silicon substrate manufactured by the floating zone method, the oxygen and carbon atoms contained in the silicon substrate are reduced, so the bonding area between these atoms and silicon atoms absorbs less infrared rays. Become. That is, by further improving the transmission efficiency of infrared rays and maintaining the inside of the cavity in a negative pressure state, no noise is generated, the electrical characteristics are stabilized, and accurate temperature measurement can be performed.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross-sectional structure of an infrared sensor according to an embodiment of the present invention.

In the figure, reference numeral 10 denotes a support member called a metal stem, which is made of a metal such as soft iron plated with chromium or gold.
1 is provided. Furthermore, an infrared sensor element 12 is formed on the surface of this silicon substrate 11, and a window material 14 having a cavity portion 13 is bonded and fixed so as to cover the element 12.

The infrared sensor element 12 is a so-called bolometer element made of a silicon thin film, which detects incident infrared rays and outputs an electric signal corresponding to the detected amount via an internal lead 15 and an external lead 16 led out horizontally. It is.

This infrared sensor element 12 includes a temperature sensing part 12a whose resistance value changes depending on the amount of heat (infrared rays), and the surrounding area by preventing the heat of this temperature sensing part 12a from escaping to the support member 10 through the silicon substrate 11. and a bridge portion 12b for creating a temperature difference between the two.

Since the temperature sensing portion 12a of the infrared sensor element 12 is made of silicon, it has a negative temperature coefficient, which causes the electric resistance to decrease as the temperature increases.

Furthermore, when the silicon of the temperature sensing portion 12a is formed into a thin film by sputtering, the crystal structure becomes an amorphous silicon structure. Explaining the principle of a detector with this amorphous silicon structure using band theory, there are many levels in the forbidden band between the lower end of the conduction band and the upper end of the filled band, and electrons are also captured in these levels. has been done. When the temperature sensitive part 12a is irradiated with the incident infrared rays, the number of electrons commensurate with the amount of energy is excited from the level in the forbidden band to the conduction band, and as a result, the number of electron carriers in the conduction band increases. do. Further, holes corresponding to the number of electrons are generated at the upper end of the filled band. This increase in electrons and holes lowers the electrical resistance detected from the outside. That is, a change in electrical resistance appears that corresponds to the incident infrared energy.

Further, the window material 14 efficiently guides infrared rays from the outside to the infrared sensor element 12, and also allows the infrared sensor element 12 to
It also serves as a pressure sensor that monitors the degree of vacuum leakage in the cavity portion 13.

This window material 14 is an infrared input section formed of a semiconductor material such as an N-type silicon film (diaphragm) with a film thickness of several μm to several tens of μm, and a diffused resistor made of a P-type diffused layer 17 is formed on its surface. 18, and a support section 19 that supports the peripheral edge of the infrared input section 18.

In addition, the window material 14 excluding the infrared input section 18 and the silicon substrate 1
1 is covered and protected by an insulating layer, such as an epoxy resin layer 20, serving as a protective film.

The bottom of the window material 14 is bonded to the silicon substrate 11 by direct anodic bonding in a vacuum, thereby setting the cavity portion 13 in a vacuum state.

In other words, if air or nitrogen gas is filled in the cavity 13 or if the temperature sensing part 12a is exposed to the atmosphere, thermal convection may occur or wind blowing through the temperature sensing part 12a may cause noise. or the electrical characteristics may become unstable. Therefore, window material 1 is
4 is bonded to the silicon substrate 11, whereby: 2 the cavity portion 13 can be easily brought into a vacuum state;
These harmful effects can be prevented.

Here, "direct anode bonding" means that when bonding the window material 14 to the silicon substrate 11, a silicon oxide film is provided on the silicon substrate 11 side and also placed on the cathode side.
with the anode side facing the anode, and heat it to about 450℃ and 35℃ in a vacuum.
This means applying a voltage of 0V. In addition, cavity part 1
The inside of 3 does not need to be completely vacuum, but it is sufficient if it is lower than atmospheric pressure, that is, in a depressurized state, but preferably lX1O-2
Torr or less.

If a vacuum leak occurs in this cavity part 13 over time and the internal pressure changes, the infrared input part 18 will bend due to the pressure change, and this will change the resistance value of the P-type diffusion layer 17. By detecting a change in current value in accordance with this change in resistance value via an electrode 21 formed on the upper surface of the P-type diffusion layer 17, leakage of the degree of vacuum can be monitored. Therefore, measurement accuracy can be improved by correcting the value of the output signal of the infrared sensor element 12 according to the change in the degree of vacuum.

Further, a metal film 22 having a high reflectance of infrared rays, such as a gold (Au) film 22, is formed on the inner wall surface of the window material 14. The infrared rays that entered the cavity part 13 are reflected by the temperature sensing part 12a and the bridge part 12b, and are absorbed by the wall surface of the window material 14 and converted into heat. The infrared rays reflected by the gold film 22 are focused on the temperature sensitive part 12a.

Furthermore, a cavity portion 1 is provided at the corner of the bottom surface of the infrared input portion 18.
A reinforcing section 23 is provided, which is a curved surface section continuously formed in a curved state from the side wall of 3 to the bottom surface of the infrared input section 18, thereby reinforcing the infrared input section 18 and increasing its mechanical strength. ing. This reinforcing portion 23 allows the infrared input portion 18 to be made thinner (approximately 20 μm), thereby improving the transmission efficiency of infrared rays.

In addition, when considering suitability as the window material 14, the three points of reflectance, transmittance, and absorption are most important.Among them, if the absorption rate is high, most of the incoming infrared rays will be absorbed by the window material 14.
In addition, the absorbed infrared rays warm the window material 14, and the window material 14 secondarily emits heat (infrared rays). As a result, the sensor will sense infrared rays from the outside (body temperature) and infrared rays from the window material 14, so it is necessary to separate these, resulting in a very complicated system. Silicon has a low absorption rate and is highly workable, so it is optimal as the window material 14. Silicon has a high reflectance, so its transmittance is about 50%.

Furthermore, in silicon substrates, absorption waveforms due to stretching and bending such as 15i-0-5-31-C- appear at infrared wavelengths of around 10 μm, resulting in poor infrared transmittance. It is preferable to use sea urchins produced by the floating zone (FZ) method, which contains fewer atoms and oxygen atoms.

5 As described above, in the above-mentioned infrared sensor, the window material 14 can improve the incidence efficiency of infrared rays, and also improve the efficiency of condensing light to the temperature sensing part 12a.

Furthermore, compared to an infrared sensor with a conventional structure, the window material 14 and the infrared sensor element 12 can each be finely processed using a semiconductor process, and there is no need for a metal cap as a window material. This eliminates the need for a flange on the stem, allowing the package to be significantly smaller in size.

In addition, in this infrared sensor, the temperature of the temperature sensing part 12a of the infrared sensor element 12 rises due to the incident infrared rays, but the temperature must be as high as possible. Temperature sensitive part 1 on top of the oxide film
2a, and in order to reduce the heat capacity, semiconductor microfabrication technology is used to make the silicon oxide film bridge part 12b thinner, narrower, and longer, and the metal from which the electric signal is taken out is made of a metal with poor thermal conductivity, such as titanium, and is made thinner 6. Moreover, by using a thinner sensor, the measurement speed becomes faster.

FIG. 2 shows the structure of an infrared sensor according to another embodiment of the present invention.

That is, in the infrared sensor shown in FIG.
is bonded to the upper surface of the silicon substrate 11 to cover only the infrared sensor element 12. However, in this embodiment, the window material 24 is fixed to the surface of the support member 10 with adhesive, for example, in the same way as the silicon substrate 11. , the structure is such that the entire silicon substrate 11 is covered, and the size can be reduced in this embodiment as well as in the above embodiment.

Further, the reinforcing section 25 of the infrared input section 18 is not a curved section but an inclined section that changes linearly, and a gold film 22 as a reflective film is formed on this reinforcing section 25.

Regarding the manufacturing method of the infrared sensor, Fig. 3(a) shows the manufacturing method of the infrared sensor.
~(p) will be explained more specifically.

First, a silicon substrate 30 as shown in FIG. 3(a) is prepared, and as shown in FIG.
Wet oxidation is performed for several minutes to form a silicon oxide film 31 with a thickness of 5,000 yen on the surface. Subsequently, as shown in FIG. 3(c), a film with a thickness of 1.5 to 1.5 mm is deposited on the silicon oxide film 31 by a vapor deposition method to serve as a sacrificial layer for forming the bridge portion 12b described above.
A 2.0 gm metal film, for example, a molybdenum film 32 is formed. In addition to the metal film, a phosphorus silicate glass (PSG) film or the like can also be used as this sacrificial layer.

Subsequently, as shown in FIG. 3D, a photoresist film 33 having a thickness of 1.0 μm is coated on the surface of the molybdenum film 32, and a sacrificial layer pattern is formed by ordinary photolithography. That is, after mask alignment, exposure and development are performed, and further heat treatment (8-do baking) is performed at 140±2° C. for 90 seconds in a nitrogen (N2) atmosphere.

Next, as shown in the same figure (e), carbon fluoride (CF4) is applied using the patterned photoresist film 33 as a mask.
Plasma etching is performed to selectively remove the molybdenum film 32. Furthermore, the gas pressure 5, OOTo
rr, plasma ashing (ashing) was performed for 4.5 seconds under the condition of high frequency power of 500 W, and the photoresist film 33
remove.

Next, as shown in the same figure (f), the pressure is 0.9 Torr,
Under the condition of fi degree 300±2℃, silane (S i H,) = 200sccm and laughing gas (N2
0) = 4000 sec, a film with a thickness of 900 mm without any impurities is formed on the entire surface of the sea urchin eight using the CVD method (chemical vapor deposition method).
A silicon oxide film 34 having a thickness of 0±1500 is formed.

Next, as shown in FIG. 3(g), sputtering is performed using a silicon substrate specific resistance of 300 Ωcm as a target, and a film with a thickness of 1.0 to 1.5 cm is formed on the silicon oxide film 34.
A silicon film 35 with a thickness of μm is formed, and an acceleration voltage of 120
KeV, dose 1, OX 10'! '/cm
Boron ions are implanted under the following conditions to bring the silicon film 35 close to a neutral semiconductor type. Subsequently, the silicon film 935 is heated (annealed) for 30 minutes in a nitrogen atmosphere at a temperature of 1100° C. to crystallize the silicon film 935. As a result, the B constant (temperature coefficient of resistance) of the above-mentioned temperature sensing portion 12a can be set to about 5000, and sensitivity to temperature changes (changes in resistance value) can be improved.

Next, as shown in the figure (h), a photoresist film 36 with a film thickness of 1.0 μm is formed by coating on the silicon film 35, mask alignment is performed, and after exposure and development, a photoresist film 36 with a thickness of 140 ± 2 By performing heat treatment (hard baking) at .degree. C. for 90 seconds, a pattern of the temperature sensing portion 12a is formed.

Next, as shown in Figure (i), oxygen (0
°) = 45 ± 1 sccm, sulfur fluoride (SF, ) =
Flowing 135±2 sec, pressure 400 mTorr
, the above photoresist film 3 under the condition of high frequency power of 125W.
The silicon film 35 is selectively removed by performing plasma etching using 6 as a square.

Next, as shown in the same figure (j), the electric power 5. OKW, temperature 23
Titanium (Ti
) for 91 seconds to form a titanium film 37 with a thickness of 0.6±0.1 um. Subsequently, as shown in FIG. 6(k), an electrode pattern of the photoresist film 38 is formed in the same manner as in the above-mentioned step (h).

Next, as shown in Figure (I), boron trichloride (B C12s ) = 47 sec and chlorine (
CI22) = 39 sec, helium (He) 1
Flowing 500sec, pressure 135Pa, power 320W
A titanium electrode film 39 is formed by performing dry etching for 130 seconds under the following conditions. Then pressure 5,
Plasma ashing (ashing) was performed for 4.5 seconds under the conditions of OTorr and high frequency power of 500W, and the photoresist film 3
Remove 8.

Next, as shown in FIG. 4(m), a pattern of a photoresist film 40 is formed using photolithography for opening the sacrificial layer in the same manner as in the above-described process.

Thereafter, as shown in FIG. 4(n), wet etching was performed for 45 seconds using a hydrogen fluoride aqueous solution (HF:H,O=1:10) using the patterned photoresist layer 40 as a mask to remove the silicon oxide. An opening 41 reaching the molybdenum film 32 is formed in the film 34 . Subsequently, the wafer was washed with running ultrapure water five times for 5 minutes each, and
Further, it is dried by a spin dry method.

Next, as shown in the same figure (p), phosphoric acid (H) was added.

PO4): Nitric acid (HNO3): Water (I20) 5:1:4
Etching is performed in an etching solution using the photoresist film 40 as a mask to remove the molybdenum film 32 as the sacrificial layer.

Finally, as shown in the same figure (p), plasma ashing (ashing) is performed under the conditions of a pressure of 5.0 Torr and a high frequency power of 500 W.
is performed for 4.5 seconds, and the photoresist film 40 is removed.

In this way, the silicon film 35 and the titanium electrode film 39
It is possible to manufacture an infrared sensor element including a temperature sensing portion made of the above and a bridge layer made of the silicon oxide film 34.

Figure 4 shows the manufacturing method for the window material shown in Figure 2.
This will be specifically explained with reference to a) to (h).

First, as shown in FIG. 4(a), a semiconductor substrate, such as a P-type silicon substrate (resistivity 4 to 8 Ωcm) 5 manufactured by the floating zone method and having a (100) plane, is prepared.
After cleaning both sides of this silicon substrate 50, an N-type layer (resistivity: 10 to 20 Ω·cm) 51 is formed on one side by epitaxial growth. Note that this N-type layer 51 may be formed by diffusing N-type impurities into the surface of the silicon substrate 50 using a diffusion method.

Next, as shown in the same figure (b), the temperature was set to 790 ± 4°C, the gas flow rate was set to (S, H2Cρ2) = 120 ± 4 sec,
Ammonia (NH3) = 40±2 sec, pressure 1
At a pressure of 70±10 mTorr, a silicon nitride film 52 with a thickness of 2,000 yen is formed on each side of the wafer by the CVD method.

Subsequently, as shown in FIG. 5C, a photoresist film having a cavity pattern is formed on the silicon nitride film 52 by ordinary photolithography. Then, using this photoresist film as a mask, plasma etching is performed to selectively remove the silicon nitride film 52 under the conditions of a pressure of 400±10 mTorr and a reaction gas of sulfur hexafluoride (SF6)=150±2 sec. Subsequently, the wafer was etched with an etching solution (H2SO
4': H20□=2:1) for 10 minutes to remove the photoresist film.

Next, the pressure is 0.3 Pa, the argon gas flow rate is 10 sec.
After performing sputter etching for 5 minutes at m, the same figure (d
), aluminum film 53 having a thickness of 1.0±0.1 μm is formed by vapor deposition of aluminum (A° C.) for 91 seconds under conditions of a temperature of 230±30° C. and a power of 5 KW.

Subsequently, in a nitrogen gas atmosphere at a temperature of 45°C,
Apply heat treatment for 1 minute.

Next, in a concentrated hydrogen fluoride aqueous solution, anodic formation is performed at a formation rate of 4 10 μrn/Hr by passing a current of 200 mA/cm 2 using the wafer as an anode and the platinum electrode as a cathode. As a result, the silicon substrate 50 becomes porous from the back side as shown in FIG. 5(e), and an anodized layer 54 is formed. Note that this anodization is stopped approximately 50 μm before the boundary between the silicon substrate 50 and the N-type layer 51. That is, this determines the size of the reinforcement portion 56 mentioned above.

Next, as shown in FIG. 6(f), the wafer was etched with an anisotropic etching solution (HF:HNO3:CH).

C00H=l:3:40) for 2 minutes to selectively remove the anodized layer 54, thereby forming the cavity portion 55. Subsequently, etching was performed at an etching rate of 2 μm/min by immersion in an anisotropic etching solution (NH, NH2:H2O:l:1) at a temperature of 105±3°C.
Perform anisotropic etching for 5 minutes. As a result, the same figure (
As shown in g), a reinforcing portion 56 having an inclined surface 56a is formed at a corner of the ceiling surface of the cavity portion 55.

Finally, the wafer was heated to 180±5°C with phosphoric acid (H).
3PO4) Soak in the solution for 55 minutes to remove the silicon nitride film 5.
When 2 is removed, a window material 57 as shown in FIG. 5(h) is obtained.

・Next, the outside sensor is erected by plasma CVD at 350°C on the silicon substrate 30 side.
After forming a silicon oxide film by the method, the wafer is placed on the anode side, and the window material 14 is placed on the anode side in a vacuum (1
The window material 57 is bonded onto the silicon substrate 30 by heating at about 450° C. (0-2 Torr) and applying a voltage of 350 V.

Next, the sensor assembled in this way is pellet-bonded onto the support member on which the external leads are arranged, followed by wire bonding of the internal leads, and then bottled with epoxy resin as a protective film and dried. By doing so, an infrared sensor can be manufactured.

Although the present invention has been described above with reference to Examples, the present invention is not limited to the above-mentioned Examples, and can be modified in various ways without changing the gist thereof.

For example, in the above embodiment, silicon was used as the material for the window material 14.57, but germanium (Ge), zinc selenide (ZnSe), gallium arsenide (GaAs
) semiconductor materials, as well as odorous thallium iodide (
It is also possible to use plastic materials such as KH2-5) and thallium bromochloride (KH2-6). Furthermore, the diffusion resistance layers of the window materials 14 and 24 are not necessarily required, and can be omitted in sensors that do not require high detection accuracy.

[Effects of the Invention] As explained above, the infrared sensor according to the present invention has a structure in which an infrared sensor element manufactured by microfabrication in a semiconductor process and a window material are integrated, and the stem has a flange portion. Since this is not necessary, it is possible to realize a small and inexpensive infrared sensor. Furthermore, if the window material is also manufactured using a semiconductor process, it will become more compact.

In addition, a reinforcing section consisting of a curved or sloped section is provided at the corner of the bottom of the infrared input section to increase the mechanical strength of the infrared input section. ), and the transmission efficiency of infrared rays can be improved.

In particular, by forming the window material using a silicon substrate manufactured by the floating zone method, the transmission efficiency of infrared rays is further improved, and if the inside of the cavity is maintained in a depressurized state, noise generation is eliminated. , it is possible to provide an infrared sensor that has stable electrical characteristics and can perform accurate measurements.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of an infrared sensor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of an infrared sensor according to another embodiment of the present invention, and FIGS. 3(a) to (p) FIG. 4(a) is a cross-sectional view showing an example of the manufacturing process of an infrared sensor, respectively.
-(h) are sectional views showing the manufacturing process of the window material of FIG. 2. 10... Supporting member, 11... Silicon substrate 1
2... Infrared sensor element 12a... Temperature sensing part, 12b... Bridge part
8 3... Cavity part, 5... Internal lead, 7... P-type diffusion layer, 9-... Support part, 3.25... Reinforcement part 14.24... Window material 16... External lead 18...Infrared input section 20...-Epoxy resin layer

Claims (6)

[Claims] (1) A support member, a semiconductor substrate supported on the support member, and an infrared sensor element formed on the surface of the semiconductor substrate that detects infrared rays and outputs an electrical signal according to the detected amount of the infrared rays. an infrared sensor comprising: an infrared input section; and a window material having a cavity corresponding to the infrared input section and guiding infrared rays input through the infrared input section to the infrared sensor element, the infrared sensor comprising: an infrared input section; An infrared sensor characterized in that the input part is deformable according to the internal pressure of the cavity part, and a reinforcing part is provided on at least a part of a corner of a bottom surface of the infrared input part. (2) The infrared sensor according to claim 1, wherein the reinforcing portion is a curved portion continuously formed in a curved state from the side wall of the cavity portion to the bottom surface of the infrared input portion. (3) The infrared sensor according to claim 1, wherein the reinforcing portion is an inclined portion continuously formed in a straight line from the side wall of the cavity portion to the bottom surface of the infrared input portion. (4) The infrared sensor according to any one of claims 1 to 3, wherein the window material is formed of a semiconductor substrate. (5) The infrared sensor according to claim 4, wherein the semiconductor substrate is a silicon substrate manufactured by a floating zone method. (6) The infrared sensor according to any one of claims 1 to 5, wherein the cavity section is set to a negative pressure state.