JP2006170945A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device capable of detecting uniformly an infrared ray with high sensitivity, as the semiconductor device for detecting the infrared ray, and capable of restraining a manufacturing cost, and to provide its manufacturing method. <P>SOLUTION: This semiconductor device 50 has an infrared absorption part 5 for absorbing the infrared ray emitted from a measuring object, and a temperature detecting part 6 for detecting a temperature change of the infrared absorption part 5. A cavity part 3 is formed to separate thermally a thermal separation area 1 formed with the temperature detecting part 6 from a silicon substrate 2, in an under side of the temperature detecting part 6, and the cavity part 3 is formed into a substantially uniform height. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor device that detects the temperature of an object to be measured by detecting infrared rays, and a manufacturing method thereof, and more particularly, a semiconductor configured as an infrared image sensor that detects infrared rays having a wavelength of about 10 μm by a plurality of detection units. The present invention relates to an apparatus and a manufacturing method thereof.

  Conventionally, a quantum type and a thermal type are known as infrared image sensors (also simply referred to as “infrared sensors”) for detecting heat of a measurement object. Quantum infrared image sensors have the advantages of relatively high sensitivity and fast response speed, but on the other hand, they have a large thermal noise, and there is a problem that they cannot be used unless the system is cooled. This means that it is necessary to provide cooling means in the system, and as a result, the manufacturing cost of the system increases.

  On the other hand, thermal image sensors can be further classified into a thermistor type, a bolometer type, a pyroelectric type, and a thermoelectromotive force type. Among these, the thermistor type and bolometer type are easy to manufacture using a normal semiconductor manufacturing process, particularly a silicon process, and can be manufactured at a lower cost than other types, and the detection circuit, In recent years, the development has been progressing because it is advantageous for forming a single chip including an electric circuit such as a readout circuit.

  Next, the principle of temperature detection using an infrared sensor will be briefly described. Normally, every object emits infrared light of a predetermined wavelength under conditions of absolute zero or higher, and the relationship between a black body (an ideal object that absorbs all incident radiant heat and reflects nothing) and thermal radiation is Determined by Planck's radiation law. Even for an object that is not a black body, the radiant energy may be multiplied by a predetermined emissivity (for example, the emissivity of human skin is about 0.98). In the case of human beings, when the body temperature is set to 36 ° C., the emitted infrared light has a wavelength distribution of about 3 to 60 μm, of which about 8 to 14 μm occupies about half.

  Infrared sensors for detecting infrared rays generally have an infrared absorbing portion that increases in temperature by absorbing infrared rays, and a temperature detecting portion that converts a temperature change of the infrared absorbing portion into an electrical signal and outputs the electrical signal. is doing. And since the intensity | strength of infrared rays is weak, in order to detect the infrared rays favorably, the said infrared absorption part and temperature detection part (these may be collectively called "sensor part") are other structure parts. In order to improve the sensitivity of the sensor, it is desirable that the heat capacity of the sensor unit be small so that the temperature rises easily even when a small amount of infrared light is incident, while being thermally separated from the silicon substrate (for example, a silicon substrate). Furthermore, the uniformity of heat flow in the sensor unit, which is determined by the physical constants of the infrared absorption unit and the temperature detection unit, is also important.

  FIG. 4 is an example of an infrared sensor disclosed in Patent Document 1, and shows a configuration for one pixel. The infrared sensor shown in FIG. 4 includes a temperature detection unit 300 formed on the silicon substrate 1 and an infrared absorption unit 130 connected to the temperature detection unit 300 via a connection column 140. The infrared absorber 130 absorbs incident infrared rays so that the temperature rises. The temperature change is transmitted to the temperature detector 300 via the connection pillar 140, and the temperature change is caused by the temperature detector 300. It is converted into an electrical signal and output. In the infrared sensor of FIG. 4, a cavity 200 formed by etching is formed below the temperature detection unit 300, thereby realizing thermal separation between the temperature detection unit 300 and the silicon substrate 1. Has been.

  FIG. 5 shows an example of the infrared sensor disclosed in Patent Document 2, and the cavity 200 of the infrared sensor is formed by isotropically etching the silicon substrate 1 using a reactive gas. is there. At both ends of the cavity portion 200, stoppers 190 for controlling the shape of the cavity portion 200 are provided.

FIG. 6 shows an example of an infrared sensor disclosed in Patent Document 3, which has a metal black 136 as an infrared absorption part and a thermoelectric element 304 as a temperature detection part. In addition, as a structure portion for thermally separating them, a porous portion 201 in which the silicon substrate 1 is partially made porous is formed below the thermoelectric element 304.
Japanese Patent Laid-Open No. 10-209418 WO99 / 31471 pamphlet Japanese Patent Laid-Open No. 9-14579

  The thermal infrared sensor as described above is required to have higher sensitivity and improved uniformity of sensitivity, and to reduce manufacturing costs. In the configuration shown in FIG. 4, since the cavity 200 is formed symmetrically from the center by anisotropic etching with respect to the silicon surface orientation, the controllability of the etching shape is relatively poor and the size or shape is uniform. It is difficult to form the cavity. Moreover, it is difficult to reduce the size of the sensor because it is difficult to form a small pixel structurally. Furthermore, in the configuration as shown in FIG. 4, the heat flow tends to be non-uniform, and as a result, the output of each pixel tends to vary.

  Next, in the configuration of FIG. 5, the shape of the cavity portion 200 is defined by the stopper 190, that is, the shape is defined by a highly controllable photolithography technique, so that the cavity portion shape can be controlled well. Requires a complicated process. Further, in the configuration of FIG. 5, an SOI (Silicon on Insulator) substrate must be used as the silicon substrate 1, which leads to an increase in manufacturing cost.

  In both the configurations of FIGS. 4 and 5, the shape of the cavity is determined by symmetric etching from the center, so that when etching is performed up to the pixel end, the etching depth at the center is deep. On the other hand, the etching depth is shallow at the end of the pixel. In such a shape, since heat is relatively easy to escape, the sensitivity is lowered.

  The configuration of FIG. 6 is advantageous in that the manufacturing cost can be reduced because it is not necessary to use an SOI substrate. However, the porous portion 201 has a lower thermal resistance than the hollow portion, and is also on the opening. In addition, since there is no single crystal region, there is a problem in that the detection portion cannot be formed on the single crystal silicon while increasing the aperture ratio.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to detect infrared rays with high sensitivity and uniformity as a semiconductor device (infrared detection device) that detects infrared rays, and to manufacture the semiconductor device. An object of the present invention is to provide a semiconductor device and a method for manufacturing the same that can reduce costs.

  In order to achieve the above object, a semiconductor device of the present invention includes an infrared absorbing member that absorbs infrared rays emitted from an object to be measured, and a temperature detector that is formed on a semiconductor substrate and detects a temperature change of the infrared absorbing member. In the semiconductor device, the semiconductor substrate has a cavity below the temperature detection unit, and the cavity is formed to have a substantially uniform height.

  Moreover, such a semiconductor device of the present invention has an infrared absorbing member that absorbs infrared rays radiated from an object to be measured, and a temperature detector that is formed on a semiconductor substrate and detects a temperature change of the infrared absorbing member. A method of manufacturing a semiconductor device, the step of partially forming a selectively removable sacrificial layer inside the semiconductor substrate, and the step of forming the temperature detector in a region above the sacrificial layer And forming the infrared absorbing member above the temperature detection unit, forming a contact hole reaching the sacrificial layer from the surface side of the semiconductor substrate, and removing the sacrificial layer through the contact hole And a step of forming a cavity in the semiconductor substrate. The method of manufacturing a semiconductor device according to the present invention can be used.

  In addition, a method of manufacturing a semiconductor device according to the present invention includes an infrared absorbing member that absorbs infrared rays emitted from a measurement object, and a temperature detection that is formed on the semiconductor substrate and detects a temperature change of the infrared absorbing member. A method of manufacturing a semiconductor device having a portion, wherein a step of forming a porous portion by partially making the vicinity of the surface of the semiconductor substrate porous and epitaxially forming the surface of the semiconductor substrate so as to cover the porous portion A step of forming a single crystal semiconductor layer; a step of forming the temperature detector on the epitaxial single crystal semiconductor layer above the porous portion; and the infrared absorption above the temperature detector. You may have the process of forming a member, and the process of forming a cavity part by removing the said porous part.

  According to the semiconductor device of the present invention, since the cavity having a substantially uniform height is formed below the temperature detection unit, infrared rays are increased as an effect of thermally separating the temperature detection unit. Sensitivity can be detected, and infrared rays can be detected uniformly as an effect that the height of the cavity is substantially uniform. Moreover, since the semiconductor device of the present invention can be manufactured without using an SOI substrate, the manufacturing cost can be reduced. According to the method for manufacturing a semiconductor image pickup device of the present invention, the semiconductor device of the present invention can be satisfactorily manufactured by a relatively simple process, and the manufacturing cost is not required because the SOI substrate is not used. Can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of the semiconductor device according to the first embodiment, and illustrates a region corresponding to one pixel in the semiconductor device. Note that the term “semiconductor imaging device” used in the following description does not particularly limit the semiconductor device of the present invention.

  As shown in FIG. 1, the semiconductor imaging device 50 includes a silicon substrate 2, a temperature detection unit 6 formed on the silicon substrate 2, and an infrared absorption layer 5 formed on the outermost surface side of the silicon substrate 2. Infrared radiated from the object to be measured is absorbed by the infrared absorption layer 5 to increase the temperature of the infrared absorption layer 5, and the temperature change is detected by the temperature detector 6 and output as an electrical signal. It is an image sensor.

  The silicon substrate 2 is a substrate made of, for example, P-type (high-density P + -type) single crystal silicon. In the present embodiment, a portion near the surface of the silicon substrate 2 is a single crystal layer 4. The silicon substrate 2 has a cavity 3 therein. The cavity 3 is formed in such a size as to include at least a region below the temperature detection unit 6 and has a substantially uniform height. Specifically, the top surface and the bottom surface of the cavity 3 are formed in parallel to each other and in parallel to the substrate surface. The height of the cavity 3 is preferably about ¼ (for example, 3 μm) of the wavelength of 8 to 14 μm detected by the semiconductor imaging device 50, thereby improving the detection efficiency of the temperature detector 6. A contact hole 11 used to form the cavity 3 is provided on one side of the cavity 3, so that the cavity 3 is in communication with the outside air via the contact hole 11. .

  In the present specification, the “height” of the cavity 3 means the distance from the bottom surface to the top surface of the cavity 3. Further, the phrase “substantially uniform” means that an error of about ± 5% (in this case, about 0.15 μm) is included with respect to a certain height dimension (for example, 3 μm).

  The temperature detector 6 is formed in the thermal isolation region 1 that is thermally isolated by the cavity 3, and more specifically, is formed on the single crystal layer 4. The temperature detection unit 6 is composed of, for example, a PN diode and a resistor, and has a function of outputting a temperature change as an electrical signal. The temperature detector 6 is not particularly limited, and a thermistor type, a bolometer type, a pyroelectric type, a thermocouple type, or the like can be used. The electrical signal output from the temperature detector 6 is output to the outside through a signal processing circuit 9 formed on the substrate surface. The temperature detection unit 6 and the signal processing circuit 9 are both formed in an element formation region between the field oxide films 10, and an insulating layer is formed on each of the temperature detection unit 6 and the signal processing circuit 9. 7 is formed. More specifically, the detection circuit may be of a voltage reading type using a constant current source in which the forward current is constant.

  The infrared absorbing layer 5 is formed on the insulating layer 7 so as to cover the temperature detection unit 6 and the signal processing circuit 9. In the connection portion 8, that is, in the region where the insulating layer 7 is not formed, the infrared absorption layer 5 is in direct contact with the surface of the silicon substrate 2, and the heat of the infrared absorption layer 5 is transmitted through the connection portion 8 to the silicon substrate 2. And is transmitted from the silicon substrate 2 to the temperature detector 6. The connecting portion 8 is preferably formed to be relatively large, so that the contact area between the infrared absorption layer 5 and the silicon substrate 2 is increased, and heat of the infrared absorption layer 5 is efficiently transmitted to the silicon substrate 2. Become.

  The infrared absorption layer 5 is preferably separated for each pixel when the semiconductor imaging device 50 is viewed in plan view from the upper surface side. Thereby, the temperature detection part 6 can detect the temperature for every pixel satisfactorily without being influenced by other adjacent pixels. The material of the infrared absorption layer 5 is not particularly limited as long as the temperature of the member rises when absorbing infrared rays. For example, gold black film, Ti, VO, TiN, vanadium oxide, It may be amorphous silicon (amorphous), polysilicon (polycrystal), single crystal silicon, or the like. Further, as described above, the connection portion 8 is a portion through which the heat from the infrared absorption layer 5 passes. In order to prevent the heat from escaping into the silicon substrate 2, the cavity portion 3 is connected to the connection portion 8. It is preferable that it exists also below.

  Next, a method for manufacturing the semiconductor imaging device 50 of FIG. 1 will be described with reference to FIG. FIG. 2 is a process diagram showing a process of manufacturing the semiconductor device of this embodiment.

  First, as shown in FIG. 2A, a P-type silicon substrate 2 is prepared, and a BOX oxide film (Berried Oxide layer) 13 functioning as a sacrificial layer is partially formed. The BOX oxide film 13 can be formed using the SIMOX method. That is, oxygen ions are implanted into the substrate from the surface side of the silicon substrate 2 and heat-treated to form a BOX oxide film 13 made of silicon oxide. In the processing by the SIMOX method, the region above the BOX oxide film 13 in the silicon substrate 2 is not oxidized and remains in a single crystal silicon state. Although not an essential step in the present manufacturing process, the single crystal layer 4 can be formed on the surface of the silicon substrate 2 by performing an epitaxial process after the BOX oxide film 13 is formed.

  Next, as shown in FIG. 2B, a field oxide film 10 is formed on the surface of the silicon substrate 2 by a field oxidation process. Thereby, the area between the field oxide films 10 becomes an element formation region. The field oxide film 10 may be formed so as to reach the BOX oxide film 13.

  Next, as shown in FIG. 2C, first, the temperature detector 6 and the signal processing circuit 9 are formed in the element formation region. These structural portions can be formed using a conventionally known method. For example, the PN diode of the temperature detecting portion 6 can be formed by ion implantation of N-type impurities. Thereafter, the insulating layer 7 is formed so as to cover the temperature detection unit 6 and the signal processing circuit 9, and the portion of the insulating layer 7 that becomes the connection unit 8 is removed.

  Next, as shown in FIG. 2D, first, the infrared absorption layer 5 is formed on the outermost surface side of the substrate, and then the infrared absorption layer 5, the insulating layer 7, the field oxide film 10 and the like are partially removed. As a result, a contact hole 11 reaching the BOX oxide film 13 is formed. If necessary, for example, a wiring layer (not shown) may be formed on the infrared absorption layer 5, and Ti or the like can be used as the material of the wiring layer. Ti is a comparative material among conductors. It is preferable in that the thermal conductivity is small (0.157 W / cmk) and it is difficult to release heat.

  Next, as shown in FIG. 2E, the BOX oxide film 13 is removed by etching through the contact hole 11 using, for example, diluted hydrofluoric acid. Thereby, the place where the BOX oxide film 13 is removed becomes the cavity 3, and the semiconductor imaging device 50 is finally completed.

  Here, the removal of the BOX oxide film 13 can be carried out in more detail as follows. First, as an etching mask for dilute hydrofluoric acid etching, a silicon nitride film (not shown) is formed and patterned, and then the structure on the BOX oxide film 13 is partially etched until the BOX oxide film 13 is reached. Subsequently, as an etching mask for protecting the side surface of the field oxide film 10 exposed by this etching, a silicon nitride film (not shown) is formed again, and etching for removing the BOX oxide film 13 is performed again. . Thereby, the BOX oxide film 13 inside the substrate is removed.

  In addition, as described above, adjacent pixels are thermally separated so that the detection by the temperature detection unit 6 in the semiconductor imaging device 50 can be favorably performed without being affected by heat from other adjacent pixels. It is desirable that In this regard, the structure portion such as the contact hole 11 is advantageous for the thermal isolation between the pixels. Therefore, it is desirable to form such a structure portion, that is, a groove-like structure portion having a depth reaching the cavity portion 3 from the surface of the substrate between the pixels to perform thermal separation. As an example of the formation of the groove-like structure portion, first, a layer for protecting a wiring layer (not shown) or the like is formed in a predetermined patterning shape, and then the insulating layer 7 and the single crystal silicon on the substrate surface are etched. That's fine.

  According to the semiconductor imaging device 50 of the present embodiment as described above, the region (thermal separation region 1) including the temperature detection unit 6 is thermally separated from the inner portion of the silicon substrate 2 by the cavity 3. Therefore, even if the temperature change transmitted from the infrared absorption layer 5 through the connection portion 8 is slight, the heat is not easily escaped to the inside of the silicon substrate 2, so that the heat is efficiently transmitted to the temperature detection portion 6, resulting in In addition, the temperature detection by the temperature detection unit 6 can be performed efficiently. This means that the semiconductor imaging device 50 as a whole can detect infrared rays with high sensitivity.

  Further, in the semiconductor imaging device 50 of the present embodiment, the height of the cavity 3 is substantially uniform, and the heat flow is made uniform as compared with the conventional configuration as shown in FIGS. 4 and 5. Infrared rays can be detected uniformly. Furthermore, the semiconductor imaging device 50 can be manufactured without using an SOI substrate, and the manufacturing method according to the present embodiment is relatively simple compared to the conventional method, which is advantageous in reducing the manufacturing cost. is there.

  In the configuration of the present embodiment, the temperature detection unit 6 can efficiently detect the temperature, and the temperature resolution of the temperature detection unit 6 can be about 0.2K. In addition, when a circuit such as the temperature detector 6 is formed on single crystal silicon, the TCR (Temperature Coefficient of Resistance) of the circuit can be improved. Furthermore, a single-crystal semiconductor layer in which the temperature detection unit 6 is formed, and a silicon substrate 2 substantially below the cavity 3 (including not only the region below the cavity 3 but also a portion on the side of the cavity 3 in the drawing). It is preferable that they are electrically connected. That is, when the P-type single crystal semiconductor layer and the P-type silicon substrate 2 are connected to each other without being separated by PN separation or an insulating layer, the layer of the temperature detection unit 6 and the silicon substrate 2 are separated. Becomes the same potential, so that the power source of the circuit can be stably taken from the base substrate, for example, and the stability of the circuit is ensured. In addition, it is advantageous for reducing the area of the temperature detector 6, and thus a highly sensitive infrared image sensor with a small heat capacity is configured.

  The invention is not limited to the configuration described above, and various modifications can be made. For example, the connection part 8 in FIG. 1 is a structure in which the infrared absorption layer 5 and the surface of the silicon substrate 2 are in direct contact with each other. However, the thermal conductivity is better than other adjacent members, and heat is transmitted through the connection part 8. It is also possible to interpose another layer between the infrared absorption layer 5 and the surface of the silicon substrate 2 as long as the transmission is preferentially transmitted. The silicon substrate 2 is not limited to the P + type, and the PN type and impurity concentration of the substrate when the SIMOX method is used can be arbitrarily set.

(Second Embodiment)
The semiconductor imaging device as shown in FIG. 1 can be manufactured by a process as shown in FIG. 3 in addition to the process described above. Hereinafter, this manufacturing process will be described with reference to FIG. 3 while illustrating specific manufacturing conditions. The semiconductor imaging device 51 (see FIG. 3E) manufactured by this manufacturing process has the same structure as that of the semiconductor of FIG. 1 except that the epitaxial silicon layer 4a is formed on the cavity 3. The configuration is the same as that of the imaging device 50.

  First, as shown in FIG. 3A, a silicon substrate 2 is prepared, boron is implanted into the substrate surface by an ion implantation method, and a porous layer having a thickness of, for example, about 10 μm is formed on a part of the substrate surface by an anodization method. The material part 23 is formed. Advantages of such a porous portion 23 include that single crystal silicon can be formed on the porous portion 23 and that the etching selectivity with respect to the silicon substrate 2 is large. For example, it can be selectively removed. In addition, since the porous portion 23 ultimately defines the contour shape of the cavity portion 3 by being removed, the upper surface and the lower surface thereof are parallel to each other, in other words, the porous portion The lower surface of 23 is preferably parallel to the surface of the silicon substrate 2. Since the porous portion 23 is formed in such a shape, the height of the formed hollow portion 3 is uniform.

The formation conditions of the porous portion 23 may be as follows.
8-inch P-type (0.013-0.017 Ωcm)
Chemical conversion solution: 50% HF: IPA = 2: 1 (volume ratio)
Current density: 8 mA / cm
Current application time: 11 min
Heat treatment: 400 ° C.-1 h, low temperature oxidation in oxygen atmosphere Further, as the silicon substrate 2, only the portion to be made porous and the vicinity thereof are partially P-type (0.013-0.017 Ωcm). Others may be P-type (1-2 Ωcm) or N-type (1-2 Ωcm).

  Next, as shown in FIG. 3B, an epitaxial process is performed on the silicon substrate 2 on which the porous portion 23 is formed, and an epitaxial silicon layer 4 a is formed on the substrate surface so as to cover the porous portion 23. The epitaxial silicon layer 4a is single crystal silicon, and can be formed to a thickness of about 10 nm to several tens of μm, for example. When the silicon substrate 2 is P + type, the epitaxial silicon layer 4a on the porous portion 23 can be formed with high quality.

  In more detail, the epitaxial process is performed after filling the surface hole (not shown) of the porous portion 23 by performing the following pre-process as follows. First, the oxide film (surface oxide film, not shown) on the surface of the porous portion 23 is removed using, for example, DHF (dilute hydrofluoric acid). Thereafter, for example, surface treatment at 950 ° C. for 10 s in a hydrogen atmosphere is performed to fill the surface holes of the porous portion 23. Further, a small amount of silicon-based gas is introduced to fill the remaining surface holes.

  The steps after the epitaxial silicon layer 4a is formed on the silicon substrate 2 can be performed in substantially the same manner as described with reference to FIGS. 2 (c) to 2 (d). That is, in the step shown in FIG. 3C, the temperature detection unit 6 and the signal processing circuit 9 are formed, and then the insulating layer 7 is formed so as to cover these structural units. Next, in the step shown in FIG. 3D, the infrared absorption layer 5 is formed on the outermost surface side of the substrate, and then the contact hole 11 reaching the porous portion 23 is formed.

  Next, in the step shown in FIG. 3E, the porous portion 23 is removed by etching through the contact hole 11. Thereby, the place where the porous part 23 is removed becomes the cavity part 3, and the semiconductor imaging element 51 is finally completed. The removal of the porous portion 23 can be performed by etching using an alkaline etching solution such as KOH. Since there is a difference in etching rate between the porous portion 23 and the silicon substrate 2, the porous portion 23 is etched preferentially compared to the silicon substrate 2. The final cavity 3 has a substantially uniform height. In addition, minute irregularities are formed on the top surface of the cavity 3, and as a function effect of such irregularities, infrared absorption efficiency in the temperature detection unit 6 is improved.

  As mentioned above, although an example of the manufacturing method of the semiconductor imaging device 51 was demonstrated as 2nd Embodiment, this invention is not restricted to the process mentioned above, A various change is possible. For example, the epitaxial silicon layer 4a may be an epitaxial SiGe layer having a thickness of 10 nm to several tens of μm formed by epitaxially growing SiGe. Alternatively, such an epitaxial SiGe layer can be formed on the whole or a part of the above-described epitaxial silicon layer. In addition to the SiGe layer, an epitaxial layer such as GaAs can also be formed.

It is a figure which shows the structure of the semiconductor device of 1st Embodiment, and has shown the area | region corresponding to one pixel among semiconductor devices. FIG. 2 is a process diagram illustrating a process of manufacturing the semiconductor device of FIG. 1. It is a figure which shows the structure of the semiconductor device of 2nd Embodiment, and its manufacturing method. It is a figure which shows an example of a structure of the conventional infrared sensor. It is a figure which shows the other example of a structure of the conventional infrared sensor. It is a figure which shows the further another example of a structure of the conventional infrared sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal isolation area | region 2 Silicon substrate 3 Cavity part 4 Single crystal layer 5 Infrared absorption layer 6 Temperature detection part 7 Insulating layer 8 Connection part 9 Signal processing circuit 10 Field oxide film 11 Contact hole 13 BOX oxide film 23 Porous part

Claims (13)

In a semiconductor device having an infrared absorbing member that absorbs infrared rays radiated from a measurement object, and a temperature detection unit that is formed on a semiconductor substrate and detects a temperature change of the infrared absorbing member,
The semiconductor device according to claim 1, wherein the semiconductor substrate has a cavity below the temperature detector, and the cavity is formed at a substantially uniform height.   The semiconductor device according to claim 1, wherein the temperature detection unit is formed in a single crystal semiconductor layer made of silicon.   3. The semiconductor device according to claim 1, wherein an inner wall surface on the side close to the temperature detection portion of the hollow portion is formed in an uneven shape.   The semiconductor device according to claim 1, wherein the semiconductor substrate is a P + type silicon substrate.   5. The semiconductor device according to claim 2, wherein the single crystal semiconductor layer in which the temperature detection unit is formed and the semiconductor substrate substantially below the cavity are electrically connected. 6.   6. The semiconductor device according to claim 1, wherein at least two structural parts including the infrared absorbing member and the temperature detection part are arranged adjacent to each other. A method of manufacturing a semiconductor device having an infrared absorbing member that absorbs infrared rays radiated from a measurement object, and a temperature detection unit that is formed on a semiconductor substrate and detects a temperature change of the infrared absorbing member,
Partially forming a selectively removable sacrificial layer inside the semiconductor substrate;
Forming the temperature detector in a region above the sacrificial layer;
Forming the infrared absorbing member above the temperature detector; forming a contact hole reaching the sacrificial layer from the surface side of the semiconductor substrate; and removing the sacrificial layer by etching through the contact hole And a step of forming a cavity in the semiconductor substrate.   The method of manufacturing a semiconductor device according to claim 7, wherein the step of partially forming the sacrificial layer includes forming an oxide film in the semiconductor substrate by a SIMOX method. A method of manufacturing a semiconductor device having an infrared absorbing member that absorbs infrared rays radiated from a measurement object, and a temperature detection unit that is formed on a semiconductor substrate and detects a temperature change of the infrared absorbing member,
Forming a porous portion by partially making the vicinity of the surface of the semiconductor substrate porous;
Forming an epitaxial single crystal semiconductor layer on the surface of the semiconductor substrate so as to cover the porous portion;
Forming the temperature detection part on the epitaxial single crystal semiconductor layer and in a region above the porous part;
Forming the infrared absorbing member above the temperature detection unit;
Forming the cavity by removing the porous portion.   The method for manufacturing a semiconductor device according to claim 9, wherein the epitaxial single crystal semiconductor layer is silicon.   The method of manufacturing a semiconductor device according to claim 9, wherein the semiconductor substrate is a P + type silicon substrate.   The method for manufacturing a semiconductor device according to claim 9, wherein the step of removing the porous portion includes performing etching with an alkaline aqueous solution.   The method of manufacturing a semiconductor device according to claim 12, wherein the step of removing the porous portion includes performing etching with a KOH aqueous solution.

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