JP2005030871A - Method of manufacturing infrared sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing infrared sensors at a low cost and in a high yield, as to a method of manufacturing noncooled-type infrared sensors, in particular. <P>SOLUTION: This method of manufacturing infrared sensors is equipped with a process for forming element domains 2 for infrared detection pixels, etc. on each semiconductor substrate 1 as to a plurality of infrared sensors, a process for forming frame body materials 3 for separating respective element domains 2 from each other on the semiconductor substrate 1 with the element domains 2 formed thereon, a process for bonding, in a vacuum, a window material substrate 4 to the semiconductor substrate 1 with the body materials 3 formed thereon and independently vacuum-sealing the element domains 2 with the body materials 3 and the material substrate 4 on a sensor-by-sensor basis, a process for removing an unnecessary portion being a portion of a window material substrate 4 between adjoining infrared sensors and not contributing to the vacuum-sealing of the element domains 2, and a process for cutting off the semiconductor substrate 1 to form chips for every infrared sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an infrared sensor, and more particularly to a method for manufacturing an uncooled infrared sensor.
[0002]
[Prior art]
Infrared imaging has the advantage of being able to capture images regardless of day or night, and has a higher permeability to smoke and fog than visible light. In addition, it can obtain temperature information on the subject. Wide application range as surveillance camera and fire detection camera.
[0003]
In recent years, the development of “uncooled infrared solid-state imaging devices” that do not require a cooling mechanism for low-temperature operation, which is the biggest drawback of conventional quantum-type infrared solid-state imaging devices, has become active. . In an uncooled type or thermal type infrared solid-state imaging device, an incident infrared ray having a wavelength of about 10 μm is converted into heat by an absorption structure, and the temperature change of the heat-sensitive part caused by the weak heat is electrically converted by some thermoelectric conversion means. Infrared image information is obtained by converting it into a signal and reading out the electrical signal, and various thermoelectric conversion means have been studied so far.
[0004]
For example, a thermopile that converts a temperature difference to a potential difference by the Seebeck effect, a bolometer that converts a temperature change of a resistor to a resistance change, a pyroelectric element that converts a temperature change to a charge by the pyroelectric effect, and a constant forward current A silicon pn junction (for example, see Non-Patent Document 1) that converts a temperature change into a voltage change has been reported.
[0005]
In such an uncooled infrared sensor, a thermoelectric conversion structure that is thermally separated from the sensor substrate is formed in order to increase the temperature change of the heat-sensitive part due to heat generated by absorbing incident infrared light. Therefore, a practical thermal separation structure is realized by adopting a MEMS structure for each pixel in a process of manufacturing a MEMS (Micro-Electro-Mechanical System) structure (see, for example, Patent Document 1). .)
[0006]
In addition, in order to achieve good thermal separation, the infrared sensor is mounted on a vacuum package to prevent a decrease in thermal resistance due to conduction and convection due to the atmosphere. For example, a structure in which a light receiving portion of an uncooled infrared sensor chip is vacuum-sealed with an infrared transmission window is disclosed (for example, see Patent Document 2).
[0007]
[Non-Patent Document 1]
Tomohiro Ishikawa, et al. , Proc. SPIE Vol. 3698, p. 556, 1999
[Patent Document 1]
JP 2002-107224 A
[Patent Document 2]
JP-A-10-115556
[0008]
[Problems to be solved by the invention]
As described above, in the uncooled infrared sensor, due to the demand for thermal separation, the heat sensitive part has a MEMS structure, and it is necessary to vacuum seal the heat sensitive part made of this MEMS structure. Therefore, the uncooled infrared sensor requires a process of mounting in a package that can be evacuated in addition to the wafer process, dicing and the like.
[0009]
A manufacturing method in which the sensor substrate is diced into chips after the process of manufacturing the MEMS structure is conceivable. However, in the dicing process, which is a normal chip forming process, there is a high possibility that the MEMS structure is damaged.
[0010]
On the other hand, a manufacturing method is conceivable in which a MEMS structure is formed on each chip after the process of dicing the sensor substrate into chips. However, in the process of manufacturing the MEMS structure after the process of forming the chip, it is necessary to handle each sensor chip with the MEMS structure that is easily damaged being exposed, and a very delicate process is required. . Therefore, the production yield is often lowered due to generation of defective chips in the MEMS structure manufacturing process.
[0011]
Furthermore, sensor characteristics must be evaluated in a state where they are mounted in a vacuum package, and it has not been possible to perform evaluation using a probe at a wafer level as in an ordinary LSI substrate.
[0012]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing an infrared sensor having a low cost and a high yield.
[0013]
[Means for Solving the Problems]
(Constitution)
In order to solve the above-described problems, the first infrared sensor manufacturing method of the present invention is configured by arranging infrared detection pixels on a semiconductor chip, and each of the infrared detection pixels absorbs incident infrared light and generates heat. An infrared absorption structure for converting into an infrared radiation; a thermoelectric conversion structure for converting a temperature change caused by heat generated in the infrared absorption structure into an electrical signal; and at least the infrared absorption structure and the thermoelectric conversion structure on the semiconductor chip. A support structure for supporting the semiconductor chip at a distance from the semiconductor chip, wherein the infrared detection pixels are formed on a semiconductor substrate for the plurality of infrared sensors, and the infrared sensor A sealing substrate is bonded in vacuum to the semiconductor substrate on which detection pixels are formed, and the infrared detection is performed independently for each infrared sensor. Vacuum sealing the element with the sealing substrate, removing unnecessary portions that do not contribute to the vacuum sealing of the infrared detection pixels, which are portions of the sealing substrate between the adjacent infrared sensors. And a step of cutting the semiconductor substrate into chips for each of the infrared sensors.
[0014]
In the manufacturing method of the 1st infrared sensor of this invention, it is desirable to provide the following structural requirements.
[0015]
(1) The sealing substrate is a silicon substrate whose both surfaces are mirror-polished.
[0016]
(2) The step of removing the unnecessary portion of the sealing substrate includes a first cutting step of incompletely cutting a part of the unnecessary portion of the sealing substrate, and completely cutting the other portion of the unnecessary portion. A second cutting step.
[0017]
(3) After the first and second cutting steps, a step of attaching an adhesive sheet to the surface of the sealing substrate including unnecessary portions of the sealing substrate, and a step of removing the unnecessary portions together with the adhesive sheet And provided.
[0018]
(4) The infrared detection pixels are two-dimensionally arranged on the semiconductor chip.
[0019]
In the second infrared sensor manufacturing method of the present invention, infrared detection pixels are arranged on a semiconductor chip, and each of the infrared detection pixels absorbs infrared light and converts it into heat. A structure, a thermoelectric conversion structure for converting a temperature change due to heat generated in the infrared absorption structure into an electrical signal, and at least the infrared absorption structure and the thermoelectric conversion structure are separated from the semiconductor chip on the semiconductor chip. A support structure for supporting the infrared sensor, wherein the infrared detection pixels are formed on a semiconductor substrate for the plurality of infrared sensors, and the infrared detection pixels are formed. Forming a frame member for separating the infrared sensors from each other on a semiconductor substrate; and attaching a window substrate to the semiconductor substrate on which the frame member is formed. Adhering inside, vacuum-sealing the infrared detection pixels by the frame body material and the window material substrate independently for each infrared sensor, and the window material between the adjacent infrared sensors A step of removing an unnecessary portion that does not contribute to vacuum sealing of the infrared detection pixels, and a step of cutting the semiconductor substrate into chips for each of the infrared sensors. To do.
[0020]
In the manufacturing method of the 2nd infrared sensor of this invention, it is desirable to provide the following structural requirements.
[0021]
(1) The window material substrate is a silicon substrate whose both surfaces are mirror-polished.
[0022]
(2) The step of removing the unnecessary portion of the window material substrate includes a first cutting step of incompletely cutting a part of the unnecessary portion of the window material substrate, and completely cutting the other portion of the unnecessary portion. A second cutting step.
[0023]
(3) After the first and second cutting steps, a step of attaching an adhesive sheet to the surface of the sealing substrate including an unnecessary portion of the window material substrate, and a step of removing the unnecessary portion together with the adhesive sheet And provided.
[0024]
(4) The infrared detection pixels are two-dimensionally arranged on the semiconductor chip.
[0025]
(Function)
In the present invention, an infrared detection pixel of an infrared sensor is formed on a semiconductor substrate as a MEMS region, the semiconductor substrate on which the infrared detection pixel is formed, and a window material substrate (sealing substrate) having a high transmittance for infrared rays. Are bonded in vacuum to vacuum seal the MEMS region of the infrared sensor at the wafer level, and unnecessary portions that do not contribute to vacuum sealing of the window material substrate (sealing substrate) in the wafer state are removed. ing.
[0026]
According to the present invention, it is possible to perform the process of manufacturing the MEMS structure of the infrared sensor in a wafer state, and it is possible to prevent the yield from being reduced due to chip handling. Also, since the vacuum sealing of the infrared sensor has been completed in the wafer state, a delicate vacuum package mounting process with the MEMS region exposed (chip handling, chip mounting, vacuum sealing at the chip level with window material) Stop) is not necessary, and the yield reduction in the mounting process can be prevented. Furthermore, since a structure for evacuation is not required in chip mounting, the package cost can be greatly reduced.
[0027]
In addition, according to the present invention, since the vacuum sealing of the infrared sensor is completed in the wafer state and the operation as the infrared sensor is possible, the evaluation by the tester can be performed at the wafer level as in the case of a normal LSI substrate. Thus, the device evaluation time can be greatly shortened.
[0028]
Therefore, according to the present invention, it is possible to provide a low-cost method for manufacturing an infrared sensor having a high manufacturing yield and a low device evaluation cost.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0030]
FIG. 3 is a drawing showing a completed structure of an infrared sensor chip manufactured by the method for manufacturing an infrared sensor of the present invention, FIG. 3 (a) is a plan view thereof, and FIG. 3 (b) is a diagram B of FIG. 3 (a). Sectional drawing in -B 'is shown. As shown in FIG. 3, an element region (MEMS region) 2 for infrared detection is provided on the surface region of the chip substrate 101 of the uncooled infrared sensor. The element region 2 is formed with infrared detection pixels arranged in an array and signal reading means (not shown) provided around the infrared detection pixels and reading signals from the infrared detection pixels. That is, as disclosed in Japanese Patent Application Laid-Open No. 2002-107224 and the like, a vertical address circuit and a horizontal address circuit for pixel selection are arranged adjacent to the infrared detection pixel array as the signal reading unit and are selected. An output unit for sequentially outputting the signals from is provided. The specific structure and manufacturing method of the infrared sensor will be described later.
[0031]
A frame member 3 is provided around the element region 2 for infrared detection, and an infrared transmission window 104 is joined to the frame member 3 so as to cover the element region 2. The space 100 surrounded by the frame body material 3, the infrared transmission window 104, and the chip substrate 101 is vacuum-sealed. The degree of vacuum may be a degree that does not deteriorate the sensor characteristics. As shown in -115556, it may be 0.01 Torr or less.
[0032]
Reference numeral 10 denotes a bonding pad for outputting a signal read from the infrared detection pixel by the signal reading means to the outside. Here, the bonding pads 10 are arrayed only along one set of opposite sides of the chip substrate 101, but the bonding pads 10 may be arrayed along all four sides.
[0033]
Next, a method for manufacturing the infrared sensor chip shown in FIG. 3 will be described in detail. 1 and 2 are process diagrams for explaining a method of manufacturing the infrared sensor chip shown in FIG. 3. The left figure is a wafer plan view for each process, and the right figure is an AA 'sectional view. is there. In FIG. 1 and FIG. 2, it is described that it is possible to obtain a total of four sensor chips in two rows and two columns from the uncooled infrared sensor substrate 1, but the size of the sensor substrate 1 and the size of the sensor chip It is possible to obtain an arbitrary number of chips by appropriately selecting the combination.
[0034]
First, as shown in FIG. 1A, a sensor substrate (semiconductor substrate) 1 is prepared, and a plurality of element regions 2 for detecting infrared rays are arranged in an array on the surface region. One element region 2 corresponds to one infrared sensor chip. In each of the plurality of element regions 2, elements for detecting infrared rays are arranged in an array corresponding to the pixels, and a signal readout circuit is provided around each element. As an element for detecting infrared rays, for example, one or a plurality of diodes having a silicon pn junction that converts a temperature change into a voltage change by a constant forward current are connected in series.
[0035]
4 and 5 are process cross-sectional views for explaining a manufacturing process (MEMS manufacturing process) of each infrared detection pixel in each element region 2 of the infrared sensor according to this embodiment, and FIG. 6A and 6B are diagrams illustrating a completed structure of an infrared detection pixel, in which FIG. 6A is a plan view and FIG. 6B is a cross-sectional view taken along a line CC ′ in FIG.
[0036]
First, as shown in FIG. 4A, a single crystal silicon substrate 1 ′ is prepared, and an insulating film 111 such as a silicon oxide film is formed on the single crystal silicon substrate 1 ′ (FIG. 4B). Next, a single crystal or polycrystalline silicon layer is stacked over the insulating film 111. This laminated structure corresponds to the sensor substrate 1. As the sensor substrate 1, a so-called SOI (Silicon On Insulator) substrate in which a single crystal silicon supporting substrate, a buried silicon oxide film layer, and a single crystal silicon layer are sequentially stacked may be used. The manufacturing process starts from a laminated structure equivalent to c) (the silicon layer is not patterned).
[0037]
For example, one or a plurality of diodes connected in series as described above are formed on the silicon layer of the sensor substrate 1 corresponding to each pixel. In addition, as an example of element isolation in a general LSI manufacturing process, an STI (Shallow-Trench-Isolation) process is performed to perform element isolation between diodes. Further, this silicon layer is patterned by etching to form an infrared detection element region 112. The patterning is performed by removing the periphery of the infrared detection element region 112 for each infrared detection pixel. (FIG. 4 (c)).
[0038]
Next, as shown in FIG. 5A, wirings 113a and 113b for reading signals from the infrared detection element region 112 of each pixel to the signal reading circuit are formed. One of the wirings 113a and 113b is connected to the vertical address circuit, and the other is connected to the horizontal address circuit. Here, the infrared detection element region 112 and the wirings 113a and 113b of each pixel are formed at substantially the same height. However, an insulating film is embedded between adjacent infrared detection element regions 112. By forming the wirings 113a and 113b on the wirings 113a and 113b, the wirings 113a and 113b can be formed at a position higher than the infrared detection element region 112.
[0039]
Next, as shown in FIG. 5B, the infrared detection element region 112 and the wirings 113a and 113b are covered with a protective insulating film 114 (a silicon oxide film, a silicon nitride film, a laminated film thereof, or the like) 114. This protective insulating film 114 serves as both a passivation film such as a MOS transistor in the peripheral circuit and an infrared absorber film. Further, as shown in FIG. 5C, an etching hole 115 for forming a hollow structure is formed by RIE (Reactive Ion Etching) to expose the single crystal silicon substrate 1 ′. At this time, all regions other than the etching hole 115 are covered with the protective insulating film 114.
[0040]
Next, anisotropic silicon etching for forming a hollow structure is performed through the etching hole 115. As the anisotropic etchant of single crystal silicon, for example, by performing anisotropic etching of single crystal silicon using a chemical such as TMAH (Tetra-Methyl-Ammonium-Hydroxide), a hollow structure is formed inside the single crystal silicon substrate 1 ′. 116 is formed (FIG. 6B). In addition, a support leg structure that supports the infrared detection element region 112 and includes the wirings 113a and 113b is formed. For the formation of the hollow structure 116, an alkali etchant other than TMAH can be used, and dry etching using a fluorine-based gas can also be used. It is also possible to form a hollow structure by forming a so-called sacrificial layer and removing it by etching.
[0041]
Although not shown, peripheral circuits (such as MOS transistors) such as a vertical address circuit, a horizontal address circuit, an output unit, and a constant current source are also formed. Here, it is also possible to form support leg wirings 113a and 113b simultaneously with the gates of the MOS transistors in the peripheral circuit. That is, after forming a gate insulating layer (silicon oxide film or the like) and a polysilicon layer, the gate electrode of the MOS transistor is processed by photolithography and RIE, and at the same time, the wirings 113a and 113b are processed. A metal silicide may be formed on the gate electrode and wirings 113a and 113b by a salicide process to form a polycide structure.
[0042]
In addition, although the example which forms the diode which has a pn junction as a thermoelectric conversion means was shown, it is also possible to form other thermoelectric conversion elements, such as a bolometer using a resistance value change, for example.
[0043]
Next, a step of vacuum-sealing the element region (MEMS region) 2 is performed. That is, as shown in FIG. 1B, the frame member 3 is formed around each element region 2. The frame body material 3 is a vacuum sealing adhesive or the like, and for example, a material made of gold tin can be used. The vacuum sealing adhesive is processed into a rectangular frame shape, and this is disposed and formed on the sensor substrate 1 as a frame body material 3.
[0044]
Next, after the window material substrate 4 is disposed opposite to the element region 2, the window material substrate 4 is bonded to the frame body material 3 by performing heat treatment. For example, a gold-tin alloy containing 20 wt% tin is melted by heating to 280 ° C. or higher, and a gold-tin alloy containing 90 wt% tin is melted by heating to 217 ° C. or higher. When a silicon substrate is used as the window material substrate 4, a eutectic state of gold and silicon is formed by heating to 363 ° C. or higher, and adhesion and vacuum sealing can be performed. As a result, the window material substrate 4 is bonded to the sensor substrate 1 via the frame body material 3 (FIG. 1B).
[0045]
Here, since the space 100 for sealing the element region 2 needs to be evacuated, it is necessary to perform the bonding step in a vacuum. The degree of vacuum at the time of vacuum sealing may be a degree of vacuum that does not deteriorate the sensor characteristics as described above, and may be 0.01 Torr or less. By performing the vacuum sealing process in this manner, the element region (MEMS region) 2 can be sealed with the vacuum space 100 in a wafer state, and the sensor can be operated.
[0046]
As the window material substrate 4, it is possible to use, for example, a silicon substrate subjected to double-side mirror polishing. Further, the window material substrate 4 is not limited to a silicon substrate as long as it shows a sufficient transmission characteristic with respect to a desired infrared ray and can be vacuum-sealed. For example, a germanium substrate may be used. When a germanium substrate is used as the window material substrate 4, it is possible to perform adhesion and vacuum sealing by heating to 356 ° C. or higher.
[0047]
Prior to the vacuum sealing process, the operation of the sensor substrate 1 that has completed the process up to the MEMS manufacturing process can be evaluated by a tester or the like to select a good chip and a defective chip. Based on the evaluation result, it is possible to arrange the frame body material (vacuum sealing adhesive) 3 only on the non-defective chips, and the frame body material (vacuum sealing adhesive) 3 can be saved. .
[0048]
In addition, in the region where the vacuum sealing adhesive 3 is disposed on the sensor substrate 1, in order to improve the wettability of the vacuum sealing adhesive 3 and obtain sufficient sealing characteristics, an element region (MEMS region) 2 is provided. It is preferable to form a metal region so as to surround it. In particular, it is preferable to use a material such as TiN that has high resistance in an etching process using an alkali etchant or the like for forming a hollow structure.
[0049]
Next, as shown in FIG. 2A, a step of cutting the window material substrate 4 to remove unnecessary window material regions other than the region necessary as the window material is performed. 7 and 8 are process cross-sectional views for explaining a process of cutting the window material substrate (sealing substrate) (process of FIG. 2A) in the method of manufacturing the infrared sensor according to the present embodiment. .
[0050]
As shown in FIG. 2A, for example, first, cuts along 5-1, 2, 3, and 4 are performed as vertical cuts, and further cut into 6-1, 2, 3, and 4 as horizontal cuts. Cut along. Of course, it is necessary to adjust the cutting height in the cutting process so that the sensor substrate 1 is not cut at this time.
[0051]
More preferably, the window material substrate 4 is cut twice in each of the vertical direction and the horizontal direction. For example, from the state of FIG. 7A, as shown in FIG. 7B, for each of the vertical direction and the horizontal direction, along 5-1 and 3 and 6-1 and 3 (FIG. 2A), The odd numbered cut is performed first. In this odd-numbered cutting, the window material substrate 4 is not completely cut. Reference numeral 15a denotes a groove formed by this cutting. Next, as shown in FIG. 7 (c), the even-numbered cutting is continued along the lines 5-2, 4 and 6-2, 4 (FIG. 2 (a)) in each of the vertical direction and the horizontal direction. Do it. In the even-numbered cutting, the window material substrate 4 is completely cut. Reference numeral 15b denotes a groove formed by this cutting.
[0052]
By performing such a cutting method, when the window material substrate 4 is cut, an unnecessary window material region that is not in contact with the vacuum sealing adhesive 3 becomes free, and the cutting process is performed without hindering cutting. It can be carried out.
[0053]
Next, the window material region that is no longer necessary in the cutting step is removed (FIG. 8A). For example, adhesive tape is adhered to the surface of the window material substrate 4 and an incomplete cut surface is folded by applying an appropriate pressure to an unnecessary window material region of the window material substrate 4 to completely cut the window material substrate 4. If an adhesive tape is removed after making it into an unnecessary thing, an unnecessary window material area | region can be removed.
[0054]
As a result, a wafer in which the MEMS region 2 is vacuum-sealed by the infrared transmitting window (window material) 104 and the frame body material (vacuum sealing adhesive) 3 is completed. The bonding pad 10 appears on the surface of the sensor substrate 1 as shown in FIG. Therefore, in this state, the sensor operation can be evaluated by applying a tester in the same manner as a normal LSI.
[0055]
Finally, as shown in FIGS. 2B and 8B, the sensor substrate 1 is cut (diced) to form an infrared sensor into a chip. Dicing may be performed from the back surface side of the sensor substrate 1 or from the front surface side. For example, substrate cutting along 7-1, 2, 3 is performed as vertical cutting, and then substrate cutting along 8-1, 2, 3 is performed as horizontal cutting. Thereby, the chip formation is completed, and the infrared sensor chip shown in FIG. 3 can be obtained.
[0056]
According to the present embodiment, it is possible to perform the process of fabricating the MEMS structure of the infrared sensor in a wafer state, and it is possible to prevent the yield from being reduced due to chip handling. Also, since the vacuum sealing of the infrared sensor has been completed in the wafer state, a delicate vacuum package mounting process with the MEMS region exposed (chip handling, chip mounting, vacuum sealing at the chip level with window material) Stop) is not necessary, and the yield reduction in the mounting process can be prevented. Furthermore, since a structure for evacuation is not required in chip mounting, the package cost can be greatly reduced.
[0057]
In addition, this invention is not limited to the said embodiment as it is. For example, in the above-described embodiment, an infrared sensor configured by arranging infrared detection pixels in a two-dimensional array has been described. Of course, a one-dimensional sensor in which infrared detection pixels are arranged one-dimensionally, The present invention can be applied to other infrared sensors, and the same effect can be obtained.
[0058]
Further, the method for cutting the window material substrate (sealing substrate) is not limited to the above embodiment, and various modes can be adopted. For example, as shown in FIG. 9, various window material substrate (sealing substrate) cutting methods can be employed. FIG. 9A shows an embodiment corresponding to the above embodiment. As shown in FIG. 9B, bonding pads 10 are provided along two sides of the chip substrate 101, and a window material substrate (sealing substrate) 4 is provided. It is also possible to use both the complete cutting and cutting (dicing) of the sensor substrate 1, thereby reducing the number of cuttings and further reducing the cost of the process. Further, as shown in FIG. 9C, a bonding pad 10 is provided along one side of the chip substrate 101, and complete cutting and incomplete cutting are performed in the vertical direction, and complete cutting is performed twice in the horizontal direction. When the complete cutting of the material substrate (sealing substrate) 4 and the cutting (dicing) of the sensor substrate 1 are combined, the number of times of dicing can be minimized.
[0059]
Furthermore, regarding the structure and manufacturing method of the infrared sensor, any structure and manufacturing method can be selected by selecting the thermoelectric conversion means and the reading method.
[0060]
In addition, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0061]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the manufacturing method of an infrared sensor with a low cost and a high yield.
[Brief description of the drawings]
FIG. 1 is a process diagram for explaining a method of manufacturing an infrared sensor chip according to the present invention.
FIG. 2 is a process diagram following FIG. 1;
FIG. 3 is a view showing a completed structure of an infrared sensor chip manufactured by the method for manufacturing an infrared sensor of the present invention.
FIG. 4 is a process cross-sectional view for explaining a manufacturing process of each infrared detection pixel in each element region of the infrared sensor according to the embodiment.
FIG. 5 is a process cross-sectional view subsequent to FIG. 4;
6 is a view showing a completed structure of each infrared detection pixel of the infrared sensor manufactured by the steps shown in FIGS. 4 and 5. FIG.
FIG. 7 is a process cross-sectional view for explaining a process of cutting a window material substrate (sealing substrate) in the infrared sensor manufacturing method according to the embodiment.
FIG. 8 is a process cross-sectional view subsequent to FIG. 7;
FIG. 9 is a plan view for explaining a method of cutting a window material substrate (sealing substrate).
[Explanation of symbols]
1 Sensor substrate (semiconductor substrate)
1 'single crystal silicon substrate
2 Element area (MEMS area)
3 Frame material (vacuum sealing adhesive)
4 Window material substrate (sealing substrate)
5 Vertical cut surface of window material
6 Horizontal cut surface of window material
7 Vertical cut surface of sensor substrate 1
8 Horizontal cut surface of sensor board 1
10 Bonding pads
15a15b groove
100 vacuum space
101 Chip substrate
104 Infrared transmission window
111 Insulating film
112 Infrared detection element area
113a, 113b wiring
114 Protective insulating film
115 Etching hole
116 Hollow structure

Claims (8)

Infrared detection pixels are arranged on a semiconductor chip, and each of the infrared detection pixels absorbs infrared rays and converts them into heat, and changes in temperature due to heat generated in the infrared absorption structure. A method for manufacturing an infrared sensor, comprising: a thermoelectric conversion structure for converting to an electrical signal; and a support structure that supports at least the infrared absorption structure and the thermoelectric conversion structure on the semiconductor chip so as to be separated from the semiconductor chip. A step of forming each of the infrared detection pixels on a semiconductor substrate for the plurality of infrared sensors, and bonding a sealing substrate to the semiconductor substrate on which the infrared detection pixels are formed in a vacuum, A step of vacuum-sealing the infrared detection pixels by the sealing substrate independently for each infrared sensor; and the adjacent infrared sensors A step of removing an unnecessary portion that does not contribute to vacuum sealing of the infrared detection pixels, and a step of cutting the semiconductor substrate into chips for each of the infrared sensors. An infrared sensor manufacturing method characterized by the above. 2. The method of manufacturing an infrared sensor according to claim 1, wherein the sealing substrate is a silicon substrate whose both surfaces are mirror-polished. The step of removing the unnecessary portion of the sealing substrate includes a first cutting step of incompletely cutting a part of the unnecessary portion of the sealing substrate, and a second step of completely cutting the other portion of the unnecessary portion. A method for manufacturing an infrared sensor according to claim 1, further comprising a cutting step. After the first and second cutting steps, a step of attaching an adhesive sheet to the surface of the sealing substrate including an unnecessary portion of the sealing substrate, and a step of removing the unnecessary portion together with the adhesive sheet are provided. The method for manufacturing an infrared sensor according to claim 3. Infrared detection pixels are arranged on a semiconductor chip, and each of the infrared detection pixels absorbs infrared rays and converts them into heat, and changes in temperature due to heat generated in the infrared absorption structure. A method for manufacturing an infrared sensor, comprising: a thermoelectric conversion structure for converting to an electrical signal; and a support structure that supports at least the infrared absorption structure and the thermoelectric conversion structure on the semiconductor chip so as to be separated from the semiconductor chip. A step of forming each of the infrared detection pixels on a semiconductor substrate for the plurality of infrared sensors, and a frame for separating the infrared sensors from each other on the semiconductor substrate on which the infrared detection pixels are formed. Forming a material, and bonding a window material substrate in a vacuum to the semiconductor substrate on which the frame material is formed, for each infrared sensor. Independently vacuum-sealing the infrared detection pixel with the frame material and the window material substrate, and a portion of the window material substrate between the adjacent infrared sensors, the infrared detection pixel A method for manufacturing an infrared sensor, comprising: a step of removing unnecessary portions that do not contribute to vacuum sealing; and a step of cutting the semiconductor substrate into chips for each infrared sensor. 6. The method of manufacturing an infrared sensor according to claim 5, wherein the window material substrate is a silicon substrate whose both surfaces are mirror-polished. The step of removing the unnecessary portion of the window material substrate includes a first cutting step of incompletely cutting a part of the unnecessary portion of the window material substrate, and a second step of completely cutting the other portion of the unnecessary portion. A method for manufacturing an infrared sensor according to claim 5 or 6, further comprising a cutting step. After the first and second cutting steps, a step of attaching an adhesive sheet to the surface of the window material substrate including an unnecessary portion of the window material substrate, and a step of removing the unnecessary portion together with the adhesive sheet. The method for manufacturing an infrared sensor according to claim 7.

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