JP4089033B2 - Sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a sensor has been proposed in which a sensor portion is disposed on a single crystal silicon substrate through a support member so as to be separated from the main surface of the single crystal silicon substrate using a micro processing technique. As this type of sensor, for example, there is an infrared sensor including an infrared detection element that converts infrared energy into heat energy as a sensor unit.
[0003]
By the way, an infrared array sensor in which a large number of infrared detection elements are two-dimensionally arranged so as to detect the temperature distribution has been proposed. When this type of infrared array sensor is used, the temperature distribution is handled in the same manner as image information. Is possible. Since infrared detection elements used for this type of application need to be highly integrated, each infrared detection element must be miniaturized.
[0004]
Further, in this type of infrared array sensor, a single crystal silicon substrate is used as a substrate in order to use a CMOS with low power consumption as a switching element constituting a signal processing unit that connects the sensor unit to an external circuit.
[0005]
[Problems to be solved by the invention]
By the way, when the size (detection area) of the infrared detection element is reduced, there is a problem that the amount of energy incident on the infrared detection element is reduced and the detection sensitivity is reduced. On the other hand, when the size of the infrared detection element is increased, the yield from a single wafer is reduced, which causes a problem of increased cost. In particular, the above-described infrared array sensor uses a single crystal silicon substrate as a substrate, which has a problem of high cost. For example, if the size of the sensor unit composed of infrared detection elements is 50 μm × 50 μm and the sensor units are arranged in 320 × 240 pixels, which is a quarter of the VGA (Video Graphics Array), the area occupied by the sensor unit is usually This is very large as compared with the semiconductor element, and causes an increase in cost.
[0006]
The present invention has been made in view of the above reasons, and an object thereof is to provide a sensor capable of reducing the cost and a method for manufacturing the same.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a sensor in which a sensor unit is disposed on a substrate so as to be separated from the substrate via a support member, and the plurality of sensor units are separated from the substrate and are matrixed. A signal processing unit that connects the sensor unit to an external circuit, the substrate is made of a glass substrate that is an insulating substrate, the sensor unit is made of an infrared detection element that detects infrared rays, and the signal processing unit Is a thin film transistor using amorphous silicon formed in close contact with the sensor unit on the sensor unit so as to overlap the sensor unit in the thickness direction of the substrate, and is a single crystal silicon substrate as a substrate The cost of the substrate can be reduced and the cost of the sensor can be reduced, and the size of the sensor can be reduced. According to the first aspect of the present invention, a plurality of sensor portions are arranged apart from the substrate, and each sensor portion is composed of an infrared detection element. Therefore, a low-cost infrared array sensor can be configured to obtain an infrared image. And more advanced information can be obtained.
[0008]
The invention of 請 Motomeko 1, group plate, which has the glass substrate, it is possible to reduce the substrate cost, it is possible to increase the yield of the sensor from one glass substrate becomes easy large area Thus, the cost can be reduced, and the sensor can be manufactured using a manufacturing apparatus for a liquid crystal display device.
[0011]
The invention of 請 Motomeko 1, signal processing unit, which has the thin film transistor using amorphous silicon, a signal processing unit at a low temperature can be formed on a large area glass substrate, a process similar to the thin film transistor used for a liquid crystal display Thus, the signal processing unit can be formed, and a liquid crystal display manufacturing apparatus can be used.
[0014]
The invention of 請 Motomeko 1, the signal processing unit, since it is formed in close contact with the sensor unit on the sensor unit so as to overlap with the sensor portion in the thickness direction of the substrate, and a sensor portion and a signal processing unit By forming continuously, a manufacturing process can be simplified and cost reduction can be achieved.
[0017]
The invention according to claim 2 is the invention according to claim 1, wherein the infrared detecting element is a bolometer-type element using a semiconductor material, so that the infrared detecting element can be formed using a semiconductor manufacturing process, Consistency with the manufacturing process is good, and the cost can be reduced.
[0018]
According to the invention of claim 3, in the invention of claim 1 , since the infrared detection element is a bolometer-type element coupled with an antenna, the directivity of the infrared detection element can be increased.
[0020]
According to a fourth aspect of the present invention, in the first to third aspects of the invention, the support member is made of an insulating film and a metal film that electrically connects the sensor unit and the signal processing unit, and the sensor unit uses a semiconductor material. Since the supporting member, the sensor unit, and the signal processing unit are formed by a low-temperature manufacturing process at 450 ° C. or lower, the liquid crystal display device manufacturing apparatus can be used and the process can be used. .
[0022]
According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the support member, the sensor portion, and the signal processing portion are formed by a manufacturing process that can accommodate a substrate larger than a silicon substrate having a diameter of 300 mm. The liquid crystal display manufacturing apparatus can be diverted, and the capital investment can be reduced.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
(Reference Example 1)
The sensor of this reference example is an infrared array sensor (infrared image sensor) in which a large number of infrared detection elements are two-dimensionally arranged. As shown in FIG. 1, a sensor unit 2 comprising an infrared detection element provided with a thin film thermistor 2a. Are disposed on an insulating film 11 made of a SiN _X film formed on an insulating substrate 1 made of a glass substrate and spaced apart from the insulating film 11 via a support member 4. A switching element 3 made of an amorphous silicon thin film transistor (hereinafter referred to as an amorphous silicon TFT), which is a thin film element, is formed on the insulating substrate 1 between the insulating substrate 1 and the sensor unit 2. Here, the switching element 3 constitutes a signal processing unit.
[0024]
This infrared array sensor has a circuit configuration as shown in FIG. That is, disposed in a large number of thin film thermistor 2a is a two-dimensional array to a matrix, thin-film thermistor 2a is connected in series with the switching elements 3 whose one end is connected to one data line L ₂ in each column Yes. In addition, a control electrode (a gate electrode 31 described later) of the switching element 3 is connected to _one control line L ₁ for each row. The infrared array sensor is connected in series to the switching element 3 via the data line L ₂ and the control line driving circuit 5 connected to the gate of the switching element 3 via the control line L ₁ and turning on and off the switching element 3. The data line driving circuit 6 is provided.
[0025]
By the way, in this reference example , each sensor part 2, each switching element 3, each support member 4, the control line drive circuit 5, and the data line drive circuit 6 are arranged with respect to one insulating substrate 1. .
[0026]
The sensor unit 2 includes a thin film thermistor 2a and an infrared absorption film 22 formed on the thin film thermistor 2a. Here, the thin film thermistor 2a is composed of a thermistor element made of an amorphous semiconductor thin film deposited by a plasma CVD method, and electrode films respectively formed at both ends of the thermistor element. Alternatively, a planar electrode structure may be used. The infrared absorption film 22 is made of a SiON film and is a film provided for absorbing infrared light having a wavelength of 10 μm, and is deposited by a plasma CVD method. In the sensor unit 2, a sacrificial layer made of, for example, a polyimide film is formed on the insulating substrate 1 on which the switching element 3 is formed, and then a support member 4 is formed on the sacrificial layer, and the sensor unit 2 is formed on the support member 4. The sacrificial layer is removed by etching after the formation of the substrate. The sensor unit 2 formed of an infrared detection element is a bolometer-type element that absorbs infrared rays by the infrared absorption film 22 and absorbs infrared rays by changing the resistance value of the thin film thermistor 2a.
[0027]
The sensor unit 2 absorbs infrared rays with an antenna matched to the wavelength of infrared rays produced by using micromachining technology, and causes current to flow through a thin film thermistor connected to the antenna to generate Joule heat, thereby reducing the resistance of the thin film thermistor. An element that detects infrared rays by a change in value, that is, a bolometer-type element coupled with an antenna may be used.
[0028]
The support member 4 is composed of a SiO _x film and a SiN _x film laminated by a plasma CVD method, and metal wiring deposited by electron beam vapor deposition, and is formed in the shape shown in FIG. Here, the metal wiring is provided to insert the thin film thermistor 2a between the switching element 3 and the ground.
[0029]
The switching element 3 is a so-called reverse stagger type amorphous silicon TFT (a-Si TFT), and is formed on the gate electrode 31 made of a tantalum (Ta) film formed on the insulating substrate 1 and on the gate electrode 31. A gate insulating film 32 made of SiN _x , a semiconductor thin film (channel layer) 33 made of hydrogenated amorphous silicon (hereinafter referred to as a-Si: H) formed on the gate insulating film 32, and a semiconductor thin film 33 A channel protective film 34 made of an SiN _x film formed thereon, a pair of ohmic contact layers 38, 39 formed on both sides of the channel protective film 34 on the semiconductor thin film 33, and one ohmic contact layer 38. Drain electrode 35, source electrode 36 formed on the other ohmic contact layer 39, drain electrode 35, Over the source electrode, and a passivation film 37 formed to cover the channel protective film 34. In FIG. 1, reference numeral 12 denotes an insulating film made of a SiO _x film or a SiN _x film.
[0030]
In the switching element 3, the gate electrode 31 is connected to the control line L ₁ , the drain electrode 35 is connected to the data line L ₂ , and the source electrode 36 constitutes a part of one support portion 4 b of the support member 4. The metal electrode is connected to one electrode film of the thin film thermistor 2 a, while the other electrode film of the thin film thermistor 2 a is grounded by a metal wire that constitutes a part of the other support portion 4 a of the support member 4.
[0031]
The switching element 3 forms a gate electrode 31 by depositing and patterning a tantalum film on the insulating substrate 1, and forming a gate insulating film 32 made of a SiN _x film, an a-Si: H film, and SiN _x . After continuously depositing by plasma CVD method, patterning is performed to form a semiconductor thin film 33 made of an a-Si: H film and a channel protective film 34 made of SiN _x, and after depositing an n ⁺ a-Si: H film. The ohmic contact layers 38 and 39 made of n ⁺ a-Si: H film are formed by patterning, and after draining aluminum, patterning is performed to form the drain electrode 35 and the source electrode 36, and the SiO ₂ or SiN _x film. Is deposited by plasma CVD and then patterned to form a passivation film 37. It is manufactured by forming. Therefore, the switching element 3 as the signal processing unit is formed on the insulating substrate 1 made of a glass substrate, and the film is formed by the plasma CVD method and the vapor deposition method. Can do it.
[0032]
In this reference example, the switching element 3 serving as a signal processing unit is formed of an amorphous silicon TFT, so that an inexpensive and large-area insulating substrate 1 such as a glass substrate can be used as a substrate. Since the yield from the substrate can be increased compared to the yield from a silicon wafer having a diameter of 300 mm, cost reduction can be realized.
[0033]
As an example of the deposition conditions of the a-Si: H film by the plasma CVD method, the substrate temperature is 270 ° C., the discharge pressure is 0.9 Torr, the discharge power is 100 W, the flow rate of SiH ₄ gas is 50 sccm, and the CH ₄ gas is used. The flow rate was 170 sccm, the flow rate of B ₂ H ₆ gas was 1 sccm, and the flow rate of H ₂ gas was 249 sccm.
[0034]
By the way, TFTs constituting peripheral circuits such as the control line driving circuit 5 and the data line driving circuit 6 must have high driving capability and stability. Therefore, the polycrystalline silicon has higher mobility and higher driving speed than the amorphous silicon TFT. A silicon thin film transistor is used. Here, the polycrystalline silicon thin film serving as the channel layer of the polycrystalline silicon thin film transistor is formed by crystallizing an amorphous silicon thin film deposited by a so-called catalytic CVD method by laser annealing. By the way, the polycrystalline silicon thin film is formed by using the catalytic CVD method. The amorphous silicon thin film has better film quality if hydrogen is contained in the film, but this hydrogen causes bumping during crystallization. In order to crystallize, it is better to have less hydrogen. In general, amorphous silicon thin films deposited by catalytic CVD have a higher amount of hydrogen in the film than amorphous silicon thin films deposited by plasma CVD. Because there are few. Here, the catalytic CVD method uses a catalytic decomposition reaction between a heated catalyst body and a raw material gas placed in the vicinity of a sample substrate, so that the substrate temperature is reduced to about 300 ° C. without using plasma. This is a thin film deposition method.
[0035]
In this reference example, as an example of the deposition conditions of the amorphous silicon film by the catalytic CVD method, the catalyst material is tungsten, the catalyst temperature is 1800 ° C., the substrate temperature is 300 ° C., the reaction pressure is 0.005 Torr, and the flow rate of SiH ₄ gas. Was 1.5 sccm, and the flow rate of H ₂ gas was 20 sccm. Thus, in this reference example, the infrared array sensor can be manufactured by a low-temperature process of 450 ° C. or lower, which is lower than 600 ° C., and the area can be increased at a low cost such as non-alkali glass or low-alkali glass. A substrate can be used, and an inexpensive substrate such as a resin substrate can be used.
[0036]
In this reference example, the switching element 3 which is a signal processing unit is configured by an amorphous silicon TFT. However, if the switching element 3 is configured by a polycrystalline silicon TFT, the control line driving circuit 5 and the data line driving circuit 6 are configured. Since it can be simultaneously formed by the same manufacturing process as the polycrystalline silicon TFT constituting the peripheral circuit, etc., the cost can be further reduced.
[0037]
By the way, the liquid crystal display device having a circuit configuration similar to the circuit configuration of FIG. 2 sequentially applies a voltage to the liquid crystal elements arranged in a matrix form. Thin film transistors are used. Here, the thin film transistor in the liquid crystal display device is generally formed on a transparent substrate having a large area. Currently, for example, a glass substrate of about 55 cm × 45 cm is used, and the substrate area is further increased. It tends to be (100 cm × 100 cm). That is, the liquid crystal display device is formed by a manufacturing process that can handle a glass substrate (transparent substrate) larger than a silicon substrate having a diameter of 300 mm. On the other hand, the sensor of this reference example can be manufactured by a plasma CVD method or the like that can deal with a large area substrate at a low temperature process of 450 ° C. or lower, so that a manufacturing apparatus for a liquid crystal display device can be used, and capital investment can be reduced. Thus, the manufacturing cost can be reduced.
[0038]
(Reference Example 2 )
The basic configuration of the sensor of the present reference example is substantially the same as that of the reference example 1, and is characterized in that the position of the switching element 3 as a signal processing unit is shifted from the sensor unit 2 as shown in FIG. . In addition , the same code | symbol is attached | subjected to the component similar to the reference example 1, and description is abbreviate | omitted.
[0039]
In Reference Example 1 , since the switching element 3 is formed on the insulating substrate 1 between the insulating substrate 1 and the sensor unit 2, the size of the infrared array sensor can be reduced. 1, the switching element 3 and the sensor part 2 need to be formed sequentially.
[0040]
On the other hand, in this reference example, since the positions of the switching element 3 and the sensor unit 2 are shifted, it is possible to simultaneously form films made of the same material in the switching element 3 and the sensor unit 2 at the same time. Thus, the number of processes can be reduced, and the cost can be reduced.
[0041]
(Working-shaped state)
The basic configuration of this embodiment is substantially the same as that of Reference Example 1, and is characterized in that a switching element 3 as a signal processing unit is disposed in close contact with the sensor unit 2 as shown in FIG. . In addition , the same code | symbol is attached | subjected to the component similar to the reference example 1, and description is abbreviate | omitted.
[0042]
In the present embodiment, since the sensor unit 2 and the switching element 3 can be formed continuously, the manufacturing process can be simplified and the cost can be reduced. In the present embodiment, one support portion 4b of the support member 4 is connected to the control line L ₁ (see FIG. 2) described in Reference Example 1 as a metal wiring constituting a part of the support portion 4b. And a metal wiring connected to the data line L ₂ (see FIG. 2).
[0043]
(Reference Example 3 )
The basic configuration of this reference example is almost the same as that of reference example 1. Instead of using an amorphous silicon TFT as the switching element 3 as a signal processing unit, as shown in FIGS. 6 and 7, an MIM (Metal Insulator Metal) diode is used. Is different. In addition , the same code | symbol is attached | subjected to the component similar to the reference example 1, and description is abbreviate | omitted. In this reference example, the switching element 3 made of an MIM diode has a three-layer structure in which a tantalum (Ta) film 131, a tantalum oxide (Ta ₂ O ₅ ) film 132, and a chromium (Cr) film 133 are stacked. 133 is connected to the control line _{L 1,} a tantalum film 131 is connected to the data line _{L 2.} By using an MIM diode as the switching element 3, the switching speed is slower than when an amorphous silicon TFT is used, but the element structure is a two-terminal structure, which makes the structure simpler than the TFT and manufactured. The process is simplified and the manufacturing cost can be reduced. Note that the tantalum film 131 and the chromium film 133 are formed by sputtering deposition and patterned using a photolithography technique, and the tantalum oxide film 132 is obtained by anodizing the surface of the tantalum film 131. Incidentally, it is considered to use the MIM diodes in place of switching elements 3 which definitive in the Reference Examples and form state.
[0044]
Incidentally, in the above you facilities embodiment and the above Reference Examples, but forms a signal processing section serving as a switching element 3 to part of one of the insulating substrate 1 or the sensor unit 2, the support member the switching element 3 4 It is also conceivable to form it. In short, the switching element 3 may be a thin film element formed on at least a part of the insulating substrate 1, the sensor unit 2, and the support member 4.
[0045]
Further, in the above you facilities embodiment and the above Reference Examples, but utilizes a flat substrate such as a glass substrate as the insulating substrate 1, a resin film used as the insulating substrate 1, an insulating substrate 1 As shown in FIG. 8, it is also conceivable to bend in a cylindrical shape. In this case, the resin film is curved after the above-described sensor unit (not shown), signal processing unit (not shown), and support member (not shown) are disposed on the insulating substrate 1 made of a resin film. What should I do? Further, the insulating substrate 1 is processed into a lens shape as shown in FIG. 9, and the switching element 3 as a signal processing unit, a sensor portion (not shown), and a support member (not shown) are formed on the lens-like insulating substrate 1. ) May be provided.
[0046]
In addition, the resin film should just be a heat resistant film, for example, a board | substrate cost can be reduced by using a Kapton film and a heat resistant plastic.
When a resin film is used as the insulating substrate 1, the sensor can be manufactured using a solar cell manufacturing apparatus that manufactures a solar cell using the resin film as a substrate. In addition, when the insulating substrate 1 is processed into a lens shape, the infrared array sensor itself has a lens function, so that a conventionally required lens is not required.
[0047]
【The invention's effect】
According to the first aspect of the present invention, there is provided a sensor in which a sensor unit is disposed on a substrate via a support member so as to be separated from the substrate, and the plurality of sensor units are disposed in a matrix in a manner spaced from the substrate. The signal processing unit is connected to an external circuit, the substrate is made of a glass substrate that is an insulating substrate, the sensor unit is made of an infrared detection element that detects infrared rays, and the signal processing unit is a sensor in the thickness direction of the substrate. It consists of a thin film transistor using amorphous silicon that is formed in close contact with the sensor part on the sensor part so that it overlaps the part, and the cost of the substrate can be reduced compared to the case where a single crystal silicon substrate is used as the substrate. The cost of the sensor can be reduced, and the size of the sensor can be reduced. According to the first aspect of the present invention, a plurality of sensor portions are arranged apart from the substrate, and each sensor portion is composed of an infrared detection element. Therefore, a low-cost infrared array sensor can be configured to obtain an infrared image. And more advanced information can be obtained.
[0048]
The invention of 請 Motomeko 1, group plate, which has the glass substrate, it is possible to reduce the substrate cost, it is possible to increase the yield of the sensor from one glass substrate becomes easy large area Thus, the cost can be reduced, and the sensor can be manufactured using a manufacturing apparatus of a liquid crystal display device.
[0051]
The invention of 請 Motomeko 1, signal processing unit, which has the thin film transistor using amorphous silicon, a signal processing unit at a low temperature can be formed on a large area glass substrate, a process similar to the thin film transistor used for a liquid crystal display Thus, the signal processing unit can be formed, and the liquid crystal display device manufacturing apparatus can be used.
[0054]
The invention of 請 Motomeko 1, the signal processing unit, since it is formed in close contact with the sensor unit on the sensor unit so as to overlap with the sensor portion in the thickness direction of the substrate, and a sensor portion and a signal processing unit By continuously forming, the manufacturing process can be simplified, and the cost can be reduced.
[0057]
The invention according to claim 2 is the invention according to claim 1, wherein the infrared detecting element is a bolometer-type element using a semiconductor material, so that the infrared detecting element can be formed using a semiconductor manufacturing process, Consistency with the manufacturing process is good, and the cost can be reduced.
[0058]
The invention of claim 3 has the effect that in the invention of claim 1 , since the infrared detection element is a bolometer-type element coupled with an antenna, the directivity of the infrared detection element can be increased.
[0060]
According to a fourth aspect of the present invention, in the first to third aspects of the invention, the support member is made of an insulating film and a metal film that electrically connects the sensor unit and the signal processing unit, and the sensor unit uses a semiconductor material. Since the supporting member, the sensor unit, and the signal processing unit are formed by a low-temperature manufacturing process at 450 ° C. or lower, the liquid crystal display device manufacturing apparatus can be used and the process can be used. There is an effect.
[0062]
According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the support member, the sensor portion, and the signal processing portion are formed by a manufacturing process that can accommodate a substrate larger than a silicon substrate having a diameter of 300 mm. The liquid crystal display manufacturing apparatus can be diverted, and the capital investment can be reduced.
[Brief description of the drawings]
FIG. 1 is a main part schematic configuration diagram showing a reference example 1 ;
FIG. 2 is a circuit configuration diagram of the above.
FIG. 3 is a schematic perspective view of the main part of the above.
FIG. 4 is a main part schematic configuration diagram showing a reference example 2 ;
5 is a schematic view of the main part showing a preferred type status.
6 is a cross-sectional view of the main part showing Reference Example 3. FIG.
FIG. 7 is a main portion circuit diagram of the above.
FIG. 8 is an explanatory diagram of a main part of another configuration example of the present invention.
FIG. 9 is an explanatory diagram of a main part of another configuration example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Sensor part 2a Thin film thermistor 3 Switching element 4 Support member 4a Support part 4b Support part 31 Gate electrode 32 Gate insulating film 33 Semiconductor thin film 35 Drain electrode 36 Source electrode

Claims (5)

A sensor in which a sensor unit is disposed on a substrate via a support member so as to be separated from the substrate, and a plurality of sensor units are disposed in a matrix in a manner spaced from the substrate, and the sensor unit is connected to an external circuit. comprising a processing unit, the substrate is made of a glass substrate which is an insulating substrate, the sensor unit is made of an infrared detector for detecting infrared rays, the signal processing unit, the sensor unit so as to overlap with the sensor portion in the thickness direction of the substrate A sensor comprising a thin film transistor using amorphous silicon formed in close contact with the sensor portion . 2. The sensor according to claim 1 , wherein the infrared detection element is a bolometer type element using a semiconductor material . Infrared detecting element, a sensor according to claim 1, characterized in that an element of the bolometer type having attached antenna. The support member is made of an insulating film and a metal film that electrically connects the sensor unit and the signal processing unit. The sensor unit is made of a thin film thermistor and an infrared absorption film using a semiconductor material, and the support member, the sensor unit, and the signal processing unit. 4. The sensor according to claim 1 , wherein the sensor is formed by a low-temperature manufacturing process at 450 ° C. or lower . Support member, the sensor unit, signal processing unit according to any one of claims 1 to 4, characterized in that formed by the manufacturing process in diameter can accommodate larger substrate than a silicon substrate of 300mm Sensor .

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