JP2024013638A - Translucent substrate and junction type solid state image sensor - Google Patents

Abstract

To provide a translucent substrate that improves the yield of a junction type solid state image sensor, and the junction type solid state image sensor.SOLUTION: A translucent substrate 60 used for a junction type solid state image sensor 100 bends in conformity with the shape of a signal readout circuit board 10 that the junction type solid state image sensor 100 comprises. The translucent substrate bends by 0.2 mm or larger with a maximum load, and is 0.5 N or larger in maximum load and also 0.04 to 2.00 mm thick.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a transparent substrate and a bonded solid-state image sensor.

Conventionally, a first amorphous selenium film is formed on a CMOS (Complementary Metal Oxide Semiconductor) circuit board, a second amorphous selenium film is formed on a transparent substrate, and these A bonded solid-state imaging device is known that achieves image acquisition and charge multiplication by bonding an amorphous selenium film by applying heat and pressure (for example, see Non-Patent Document 1).

Bonded solid-state imaging devices are exposed to many heating and cooling processes during manufacturing. When a CMOS circuit board is subjected to various stresses during various processes, warping of about 1 μm to about 2 μm occurs in the pixel region (see FIGS. 7A and 7B). On the other hand, the light-transmitting substrate maintains high flatness with only approximately 10 nm of unevenness due to the established polishing process.

Miyagawa et al., NHK Giken, “Prototype of crystalline selenium multiplier membrane bonded solid-state imaging device for higher sensitivity of solid-state imaging devices”, Institute of Image Information and Television Engineers Winter Conference, 23C-1, 2021

A conventional bonded solid-state image sensor has a first amorphous selenium film formed on a slightly curved CMOS circuit board and a second amorphous selenium film formed on a highly flat transparent substrate. Since these amorphous selenium films were bonded to each other, there was a problem in that these amorphous selenium films were difficult to adhere to, resulting in a decrease in yield.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a light-transmitting substrate that improves the yield of bonded solid-state image sensors.

The light-transmitting substrate according to one embodiment is a light-transmitting substrate used in a bonded solid-state image sensor, and is characterized in that it bends along the shape of a signal readout circuit board included in the bonded solid-state image sensor. shall be.

Furthermore, in the light-transmitting substrate according to one embodiment, the light-transmitting substrate has a deflection amount of 0.2 mm or more with respect to a maximum load.

Furthermore, in the light-transmitting substrate according to one embodiment, the maximum load of the light-transmitting substrate is 0.5N or more.

Furthermore, in the light-transmitting substrate according to one embodiment, the light-transmitting substrate has a thickness of 0.04 mm or more and 2.00 mm or less.

Furthermore, in the light-transmitting substrate according to one embodiment, the light-transmitting substrate is formed of any one of single crystal sapphire, quartz, optical glass, beryllium, acrylic, and plastic. do.

Furthermore, in the light-transmitting substrate according to one embodiment, the light-transmitting substrate includes a transparent conductive film that connects from the front surface to the image acquisition area on the back surface.

A junction-type solid-state imaging device according to one embodiment includes a signal readout circuit board, an electron injection blocking reinforcing layer, a crystalline selenium film, a hole injection blocking reinforcing layer, and a structure that bends along the shape of the signal readout circuit board. A light-transmitting substrate is provided in this order.

Furthermore, in the junction type solid-state imaging device according to one embodiment, the hole injection blocking reinforcing layer is formed of any one of gallium oxide, cerium oxide, germanium dioxide, silicon nitride, and silicon carbide. It is characterized by

Furthermore, in the junction type solid-state imaging device according to one embodiment, the electron injection blocking reinforcing layer is formed of any one of molybdenum trioxide, nickel oxide, gallium oxide, antimony trisulfide, silicon nitride, and silicon carbide. characterized by being done.

According to the present invention, it is possible to provide a light-transmitting substrate that improves the yield of bonded solid-state image sensors.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a junction type solid-state image sensor according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a light-transmitting substrate used in the bonded solid-state image sensor according to the present embodiment. FIG. 3 is a diagram showing an example of a three-point bending test according to the present embodiment. It is a figure showing an example of the relationship between the amount of deflection and load concerning this embodiment. 1 is an exterior photograph showing an example of the configuration of a junction type solid-state image sensor according to the present embodiment. 1 is an exterior photograph showing an example of the configuration of a conventional junction type solid-state image sensor. 1A and 1B are a schematic diagram and a schematic sectional view showing an example of a method for manufacturing a translucent substrate according to the present embodiment. FIG. 1 is a schematic diagram and a schematic cross-sectional view showing an example of a method for manufacturing a transparent substrate according to the present embodiment. FIG. 1 is a schematic diagram and a schematic cross-sectional view showing an example of a method for manufacturing a transparent substrate according to the present embodiment. FIG. 1 is a schematic diagram and a schematic cross-sectional view showing an example of a method for manufacturing a transparent substrate according to the present embodiment. It is a figure showing an example of the state of sputtering concerning this embodiment. It is a figure showing an example of the state of sputtering concerning this embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of a signal readout circuit board used in the junction type solid-state image sensor according to the present embodiment. FIG. 3 is a schematic diagram showing an example of the flatness of a signal readout circuit board used in the junction type solid-state image sensor according to the present embodiment.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In addition, in principle, the same reference numerals are given to the same constituent elements, and redundant explanation will be omitted. In each figure, for convenience of explanation, the vertical and horizontal ratios of each structure are exaggerated from the actual ratios.

<Junction type solid-state image sensor>
An example of the configuration of the junction type solid-state imaging device 100 according to this embodiment will be described with reference to FIGS. 1 to 4B.

The bonded solid-state image sensor 100 is a light-transmitting substrate that includes a signal readout circuit board 10, an electron injection blocking reinforcing layer 20, a photoelectric conversion film 30, a hole injection blocking reinforcing layer 40, and transparent conductive films 50a and 50b. 60 and are provided in this order.

Bonded solid-state image sensor 100 is electrically connected to package 1 via bonding wire 2 . The package 1 may be a known package applied in the technical field. The bonding wire 2 may be made of a conductive material such as gold (Au), for example.

The signal readout circuit board 10 is, for example, a substrate in which a CMOS structure is formed on a silicon substrate. The signal readout circuit board 10 includes a pixel region 10D in which a plurality of pixel electrodes are provided. A plurality of pixel electrodes are provided corresponding to each pixel, and are electrically connected to, for example, the negative electrode of the power source 3. The signal readout circuit reads out charges generated and multiplied in the photoelectric conversion film 30 by the incidence of the light L through a plurality of pixel electrodes.

The pixel electrode is formed of a metal film such as gold (Au), copper (Cu), aluminum (Al), tungsten (W), molybdenum (Mo), or the like. The pixel electrode is formed, for example, by a known semiconductor manufacturing process in which a film is formed by a vacuum evaporation method, a sputtering method, or the like, and then patterned by a dry etching method or the like. The pixel electrode may have a film thickness as long as it can provide the required conductivity, and is preferably, for example, 200 nm or more and 1 μm or less. Note that an insulating film made of, for example, silicon oxide (SiO ₂ ) may be provided between the pixel electrodes.

The electron injection blocking reinforcing layer 20 has a function of blocking electron injection from a plurality of pixel electrodes to the photoelectric conversion film 30 and a function of insulating each of the plurality of pixel electrodes. The electron injection blocking reinforcing layer 20 is provided between the signal readout circuit board 10 and the photoelectric conversion film 30. By providing the electron injection blocking reinforcing layer 20, it is possible to suppress the generation of dark current in the junction solid-state imaging device 100.

The electron injection blocking reinforcing layer 20 is preferably formed of a material capable of blocking electron injection from a plurality of pixel electrodes to the photoelectric conversion film 30. Examples of such materials include molybdenum trioxide (MoO ₃ ), nickel oxide (NiO), gallium oxide (Ga ₂ O ₃ ), antimony trisulfide (Sb ₂ S ₃ ), silicon nitride (SiN), and silicon carbide. (SiC), etc. The electron injection blocking reinforcing layer 20 preferably has a thickness of 10 nm or more. Thereby, electron injection from the plurality of pixel electrodes to the photoelectric conversion film 30 can be efficiently prevented.

The photoelectric conversion film 30 is a photoelectric conversion section in the junction type solid-state image sensor 100, and generates and multiplies charges by irradiation with the light L. The photoelectric conversion film 30 is provided between the electron injection blocking reinforcing layer 20 and the hole injection blocking reinforcing layer 40.

The photoelectric conversion film 30 may be, for example, a crystalline selenium film. If the photoelectric conversion film 30 has a film thickness of 0.1 μm or more, preferably 0.3 μm or more, it is possible to realize the junction-type solid-state imaging device 100 that can obtain sufficient sensitivity in the entire visible light range. Further, the photoelectric conversion film 30 is preferably formed with a film thickness of 5 μm or less, preferably 1 μm or less, from the viewpoint of productivity because it can be formed efficiently. Note that if the voltage resistance of the signal readout circuit board 10 is high, the thickness of the photoelectric conversion film 30 can be increased, so that a higher multiplication factor can be obtained.

The hole injection blocking reinforcing layer 40 has a function of blocking hole injection (leakage current) from the transparent conductive film 50 to the photoelectric conversion film 30. The hole injection blocking reinforcing layer 40 is provided between the transparent conductive film 50 and the photoelectric conversion film 30. By forming the hole injection blocking reinforcing layer 40 on the transparent conductive film 50b, electrical short circuit between the signal readout circuit board 10 and the transparent conductive film 50 can be suppressed.

The hole injection blocking reinforcing layer 40 is preferably formed of a material capable of blocking hole injection from the transparent conductive film 50 to the photoelectric conversion film 30. Examples of such materials include gallium oxide (Ga ₂ O ₃ ), cerium oxide (CeO ₂ ), germanium dioxide (GeO ₂ ), silicon nitride (SiN), and silicon carbide (SiC). The hole injection blocking reinforcing layer 40 preferably has a thickness of 10 nm or more, and by satisfying this range, hole injection (leakage current) from the transparent conductive film 50 to the photoelectric conversion film 30 can be efficiently blocked. By doing so, generation of dark current can be suppressed.

The light-transmitting substrate 60 is preferably formed of a material that transmits light over the entire visible light range. Such materials include, for example, single crystal sapphire, quartz, optical glass, beryllium, acrylic, plastic, fiber optic (FOP), silicon, and the like. In particular, when the transparent substrate 60 is formed of single crystal sapphire, the crystal structure of the photoelectric conversion film 30 made of crystalline selenium can be easily adjusted, and furthermore, the transparent conductive film 50 and the hole injection blocking reinforcing layer 40 can be easily arranged. When subjected to high temperature treatment, crystallization of the transparent conductive film 50 and the hole injection blocking reinforcing layer 40 can be promoted.

The amount of deflection of the translucent substrate 60 under the maximum load is preferably 0.2 mm or more, more preferably 0.4 mm or more. The maximum load is a value determined based on the thickness, material, length, width, Young's modulus, distance between supporting points during loading, etc. of the transparent substrate 60, and is the load that can be applied to the transparent substrate 60. is the maximum value of

FIG. 3A is a diagram showing an example of a three-point bending test. FIG. 3B is a diagram showing an example of the relationship between the amount of deflection [mm] and the load [N]. The dotted line graph shown in FIG. 3B shows the relationship between the amount of deflection [mm] and the load [N] when using a sample whose transparent substrate has a thickness of 0.05 [mm]. The solid line graph shown in FIG. 3B shows the relationship between the amount of deflection [mm] and the load [N] when using a sample whose transparent substrate has a thickness of 0.1 [mm]. The graph of the two-dot chain line shown in FIG. 3B shows the relationship between the amount of deflection [mm] and the load [N] when using a sample with a transparent substrate thickness of 1.1 [mm]. . Note that a single crystal sapphire substrate was used as the sample.

The amount of deflection W is expressed by the following formula using the bending load P, the distance l between the supporting points, the width B of the sample of the transparent substrate 60, the thickness h of the sample of the transparent substrate 60, and the Young's modulus E. Ru.

The larger the amount of flexure, the easier the translucent substrate 60 is to flex along the shape of the signal readout circuit board 10. As a result, when joining the first amorphous selenium film formed on the curved signal readout circuit board 10 and the second amorphous selenium film formed on the transparent substrate 60, It becomes easier to improve the adhesion of these amorphous selenium films. On the other hand, the translucent substrate 60 will be destroyed if the amount of deflection is too large. Therefore, the translucent substrate 60 can be bent along the shape of the signal readout circuit board 10 when the amount of bending with respect to the maximum load satisfies the above-mentioned range (see FIG. 2).

It is preferable that the light-transmitting substrate 60 has a deflection amount of 0.02 mm or more and a load of 0.5 N or more. It is more preferable that the light-transmitting substrate 60 has a deflection amount of 0.4 mm or more and a load of 1.0 N or more, that is, a substrate that satisfies region D in FIG. 3B.

For example, as illustrated in FIG. When the transparent substrate 60 is selected from among the samples whose thickness is 1.1 [mm], the transparent substrate 60 is selected from among the samples whose thickness is 1.1 [mm]. A sample having a thickness of 0.1 mm is preferable.

The thickness of the transparent substrate 60 is preferably 0.04 mm or more and 2.00 mm or less, and more preferably 0.10 mm or more and 1.20 mm or less. When the thickness of the transparent substrate 60 satisfies the range, it becomes possible to bend the transparent substrate 60 along the shape of the signal readout circuit board 10 (see FIG. 2).

For example, when single-crystal sapphire is used as the material for the transparent substrate 60, substrate processing techniques have been established for single-crystal sapphire substrates up to a thickness of 0.05 mm. However, in general, when the thickness of a single-crystal sapphire substrate becomes thin, problems arise, such as the single crystal sapphire substrate becoming more likely to break during the cleaning process, and being unable to withstand the pressure (for example, 90 MPa) during the bonding process and being destroyed.

Therefore, the thickness of the transparent substrate 60 depends on various factors such as the characteristics of the material used for the transparent substrate 60, the processing limit value of the thickness of the transparent substrate 60, the cleaning technique, and the pressure during the bonding process. It is preferable to set it appropriately in consideration of the conditions. Note that the light-transmitting substrate 60 may be a substrate that satisfies the amount of deflection of 0.02 mm or more or the load of 0.5 N or more, taking these conditions into consideration.

The shape of the light-transmitting substrate 60 is not particularly limited, and may be, for example, rectangular, square, trapezoidal, polygonal, circular, or flexible.

As shown in FIG. 1, the transparent substrate 60 includes a transparent conductive film 50 that connects from the front surface to the image acquisition area 60D on the back surface. The transparent conductive film 50 is electrically connected to the positive electrode of the power source 3, for example. Since the transparent substrate 60 includes the transparent conductive film 50, the power source 3 and the transparent conductive film 50 in the image acquisition area 60D can be easily connected without grinding the transparent substrate 60 itself. can. Furthermore, since the transparent substrate 60 includes the transparent conductive film 50, the power source 3 and the transparent conductive film 50 can be easily connected even if the transparent substrate 60 is an extremely thin substrate.

The transparent conductive film 50a is provided in a partial area on the front surface of the transparent substrate 60, on one side surface of the transparent substrate 60, and in a partial area on the back surface of the transparent substrate 60. The partial area on the surface of the transparent substrate 60 is not particularly limited, but may be at least an area with a vertical length of 1 mm or more on the surface and a horizontal length of 1 mm or more on the surface. Bye. The partial area on the back surface of the translucent substrate 60 is not particularly limited, but may be at least an area with a vertical length of 1 mm or more on the back surface and a horizontal length of 1 mm or more on the back surface. Bye. It is desirable that the thickness of the transparent conductive film 50a on the front surface of the transparent substrate 60 is equal to the thickness on the back surface of the transparent substrate 60.

The transparent conductive film 50b partially overlaps with a partial region of the transparent conductive film 50a on the back surface of the transparent substrate 60, and is provided in the image acquisition area 60D on the back surface of the transparent substrate 60. By providing the transparent conductive film 50b so as to be connected to the transparent conductive film 50a, voltage can be easily supplied from the power source 3 to the photoelectric conversion film 30 via the transparent conductive film 50, and furthermore, the bonded solid state according to the light Sufficient conductivity in the transparent conductive film 50 can be ensured so that image acquisition by the image sensor 100 is not adversely affected.

For example, the image acquisition area 60D is set such that its vertical length is longer than the film formation surface of the photoelectric conversion film 30, and its horizontal length is set such that it is shorter than the film formation surface of the photoelectric conversion film 30. It's fine. The image acquisition area 60D may have a vertical length of 13.95 mm and a horizontal length of 25.0 mm, for example. By forming the transparent conductive film 50b in the image acquisition area 60D set in this way, it is possible to prevent leakage current to the signal readout circuit board 10 side.

The transparent conductive film 50 is preferably made of a material that is transparent and has excellent conductivity. Examples of such materials include ITO (indium tin oxide), IZO (zinc tin oxide), AZO (aluminum-doped zinc oxide), SnO ₂ (tin oxide), FTO (fluorine-doped tin oxide), and Au (gold). , Al (aluminum), Cu (copper), Mo (molybdenum), Zn (zinc), and the like. The thickness of the transparent conductive film 50 is not particularly limited, but in consideration of light transmittance and resistance value, it is preferably 5 nm or more and 50 nm or less.

Note that in the bonded solid-state imaging device 100, a wiring is pasted between the N part of the transparent conductive film 50 and the voltage supply section 11 using a conductive paste or the like, so that the transparent conductive film 50 and the voltage supply section 11 are connected to each other. may be electrically connected to realize image acquisition using the signal output 7, or power may be supplied from the power supply 3 to the N portion of the transparent conductive film 50 and image acquisition may be realized using the signal output 7. It may be a configuration.

As described above, the bonded solid-state imaging device 100 according to the present embodiment includes the transparent substrate 60 that is flexible and bends along the shape of the signal readout circuit board 10. As a result, when joining the first amorphous selenium film formed on the curved signal readout circuit board 10 and the second amorphous selenium film formed on the transparent substrate 60, Since the adhesion of these amorphous selenium films can be improved, the yield of the bonded solid-state image sensor 100 can be improved. Furthermore, after these amorphous selenium films are bonded, in each layer (for example, the electron injection blocking reinforcement layer 20, the photoelectric conversion film 30, and the hole injection blocking reinforcement layer 40), the bonding force that occurs at the interface of each layer is weak. Film peeling can be suppressed.

<Verification>
FIG. 4A is an external photograph showing an example of the configuration of the junction type solid-state image sensor according to the present embodiment.
FIG. 4B is an external photograph showing an example of the configuration of a conventional junction type solid-state imaging device.

As shown in FIG. 4A, when a light-transmitting substrate with a thickness of 0.1 mm is used in a bonded solid-state image sensor, the photoelectric conversion film bond extends not only to the center of the pixel area but also to the periphery of the pixel area. It can be seen that a is formed. That is, it can be seen that the junction type solid-state image sensor shown in FIG. 4A has a large junction area of the photoelectric conversion film. Note that the two peeled parts in the center are the result of dust mixed in during the experiment, and can be considered to be part of the photoelectric conversion film bonding part.

On the other hand, as shown in FIG. 4B, when a light-transmitting substrate with a thickness of 1.1 mm is used in a bonded solid-state image sensor, a photoelectric conversion film bonding portion is formed only in the center of the pixel area, and the pixel area It can be seen that the photoelectric conversion film junction part is not formed up to the peripheral part. That is, it can be seen that the junction type solid-state image sensor shown in FIG. 4B has a narrow junction area of the photoelectric conversion film. This is due to the warpage that occurs in the signal readout circuit board, and the adhesion between the first amorphous selenium film and the second amorphous selenium film is high in the central part of the pixel area, but This is because the adhesion between the first amorphous selenium film and the second amorphous selenium film becomes low in the peripheral portion.

Furthermore, although details are not shown in the drawings, in the conventional bonded solid-state image sensor using a light-transmitting substrate, the interface between the hole injection blocking reinforcing layer and the photoelectric conversion film is Peeling had occurred. When the signal readout circuit board is pressurized by the bonding device, the warpage is corrected once, but when the pressure in the bonding device is released, it curves again, so bonded solid-state imaging It is presumed that such peeling occurred in the element.

Through the above verification, the thickness of the transparent substrate is adjusted to an appropriate value depending on the material, etc., and by making the transparent substrate itself flexible, amorphous selenium formed on the signal readout circuit board can be formed. It is suggested that the adhesion between the film and the amorphous selenium film formed on the transparent substrate can be improved.

<Method for manufacturing translucent substrate>
An example of a method for manufacturing the light-transmitting substrate 60 used in the bonded solid-state imaging device 100 according to this embodiment will be briefly described with reference to FIGS. 5A to 6B.

First, a sputtering method (oxygen gas partial pressure: 7.6×10 ⁻³ Pa, argon gas An electron injection blocking reinforcing layer 20 made of a nickel oxide film with a thickness of 10 nm is formed under a partial pressure of 6.0×10 ⁻¹ Pa). Then, a first amorphous selenium film having a thickness of 150 nm is formed on the electron injection blocking reinforcing layer 20 by, for example, a substrate rotation type resistance heating evaporation method (degree of vacuum: 1.0×10 ⁻⁵ Pa).

Next, the operator loosens the fixing screws 303a and 303b, loads the translucent substrate 60 into the fixing jig 302 provided on the turntable 301, and tightens the fixing screws 303a and 303b to fix the fixing jig. The transparent substrate 60 is fixed to the tool 302 (see FIG. 6A). By adjusting the fixing screws 303a and 303b, even if the thickness of the translucent substrate 60 changes, the translucent substrate 60 can be loaded or fixed on the fixing jig 302, and the turntable 301 will be installed in The transparent substrate 60 may be, for example, a single crystal sapphire substrate having a vertical length of 13.0 mm, a horizontal length of 20.0 mm, and a thickness of 0.1 mm.

The turntable 301 is not particularly limited in size or shape, but may have a circular shape with a radius of 200 mm, for example. Turntable 301 rotates in the direction of the arrow depicted in FIG. 6B.

The fixing jig 302 is preferably made of a material such as Teflon (registered trademark), plastic, acrylic, stainless steel, or aluminum. When the fixing jig 302 is made of Teflon, for example, it is possible to suppress scratches or chips from occurring in the transparent substrate 60.

Next, the operator places the ITO target 304, which is the material source, in a circular area with a diameter a (for example, 76.2 mm) that is shifted by a distance b (for example, 85.0 mm) from the center of the turntable 301, and The transparent substrate 60 is placed on a trajectory having a radius c (for example, 60 mm) off the center of the area (see FIG. 6B). Since the ITO target 304 has a magnet installed at the bottom, by arranging the transparent substrate 60 on such an orbit, the turntable 301 More ITO can be attached than on the transparent substrate 60 on the outer peripheral side. In other words, by simply facing the side surface of the light-transmitting substrate 60 with respect to the ITO target 304 without tilting the light-transmitting substrate 60, the inner periphery of the turntable 301 as well as the side surface of the light-transmitting substrate 60 can be The transparent substrate 60 is arranged so that the thickness of the ITO film formed on the transparent substrate 60 on the side is thicker than the thickness of the ITO film formed on the transparent substrate 60 on the outer peripheral side of the turntable 301. An ITO target 304 can be attached to the front or back surface.

Next, as shown in FIG. 5B, the operator performs first sputtering on the front, side, and back surfaces of the transparent substrate 60 using a sputtering device. As a result, a transparent conductive film 50a' that connects from the front surface to the back surface is formed.

The film forming conditions may be, for example, oxygen gas partial pressure: 7.6×10 ⁻³ Pa, argon gas partial pressure: 6.0×10 ⁻¹ Pa, and film forming time: 12 minutes. The transparent conductive film 50a' is thicker on the front surface of the transparent substrate 60 than on the back surface of the transparent substrate 60. Further, the thickness of the transparent conductive film 50a' relative to the side surface of the transparent substrate 60 is, for example, about 30 nm.

Next, as shown in FIG. 5C, the operator rotates the fixing jig 302 supporting the transparent substrate 60 by 180 degrees, and then uses a sputtering device to coat the transparent conductive film 50a'. Perform second sputtering. Thereby, a transparent conductive film 50a connected from the front surface to the back surface is formed.

The film forming conditions may be, for example, oxygen gas partial pressure: 7.6×10 ⁻³ Pa, argon gas partial pressure: 6.0×10 ⁻¹ Pa, and film forming time: 12 minutes. The thickness of the transparent conductive film 50a on the front surface of the transparent substrate 60 is equal to the thickness on the back surface of the transparent substrate 60. The thickness of the transparent conductive film 50a relative to the side surface of the transparent substrate 60 is, for example, about 60 nm.

Next, as shown in FIG. 5D, the operator performs third sputtering on the image acquisition area 60D on the back surface of the transparent substrate 60 using a sputtering device. As a result, a transparent conductive film 50b that partially overlaps the transparent conductive film 50a is formed.

The film forming conditions may be, for example, oxygen gas partial pressure: 7.6×10 ⁻³ Pa, argon gas partial pressure: 6.0×10 ⁻¹ Pa, and film forming time: 1 minute. The thickness of the transparent conductive film 50b relative to the back surface of the transparent substrate 60 is, for example, about 10 nm.

Next, on the transparent substrate 60 provided with the transparent conductive film 50 (50a, 50b) formed by performing sputtering three times: first sputtering, second sputtering, and third sputtering, for example, A hole injection blocking reinforcement layer 40 made of a gallium oxide film with a thickness of 30 nm is formed by a sputtering method (oxygen gas partial pressure: 7.6×10 ⁻³ Pa, argon gas partial pressure: 6.0×10 ⁻¹ Pa). Then, high-temperature treatment is performed at 800 degrees for 60 minutes in an oxygen atmosphere to grow crystals of the transparent conductive film 50 and the gallium oxide film. Then, a second amorphous selenium film having a thickness of 150 nm is formed on the gallium oxide film by, for example, a substrate rotation type resistance heating evaporation method (degree of vacuum: 1.0×10 ⁻⁵ Pa). Then, these amorphous selenium films are bonded by applying heat and pressure, and are crystallized to form a photoelectric conversion film 30 made of crystalline selenium. For details of the bonding process between the first amorphous selenium film and the second amorphous selenium film, refer to Non-Patent Document 1.

The bonded solid-state imaging device 100 manufactured as described above has high adhesion between the first amorphous selenium film and the second amorphous selenium film, a large bonding area of the photoelectric conversion film 30, and a large bonding area for each layer. film peeling is suppressed. Therefore, it is possible to realize the bonded solid-state imaging device 100 with improved yield.

<Modified example>
Although the present embodiment has been described as an example in which the light-transmitting substrate 60 is applied to the bonded solid-state image sensor 100, the use of the light-transmitting substrate 60 is not limited to this. For example, the transparent substrate 60 may be applied to a vacuum device such as an image pickup tube, a cold cathode image sensor, or a vacuum tube.

Although the embodiments described above have been described as representative examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of this disclosure. Therefore, the present invention should not be construed as being limited to the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of steps described in the embodiments into one, to divide one step, or to change the order of the steps.

1 Package 2 Bonding wire 3 Power source 7 Signal output 10 Signal readout circuit board 11 Voltage supply section 20 Electron injection blocking reinforcement layer 30 Photoelectric conversion film 40 Hole injection blocking reinforcement layer 50, 50a', 50a, 50b Transparent conductive film 60 Light transmission Physical substrate 60D Image acquisition area 100 Bonded solid-state image sensor

Claims (9)

A translucent substrate used in a bonded solid-state image sensor,
bending along the shape of a signal readout circuit board included in the bonded solid-state image sensor;
Transparent substrate. The transparent substrate is
The amount of deflection against the maximum load is 0.2 mm or more,
The translucent substrate according to claim 1. The transparent substrate is
the maximum load is 0.5N or more;
The translucent substrate according to claim 2. The transparent substrate is
The thickness is 0.04 mm or more and 2.00 mm or less,
The translucent substrate according to claim 1. The transparent substrate is
Made of one of the following materials: single crystal sapphire, quartz, optical glass, beryllium, acrylic, and plastic.
The translucent substrate according to any one of claims 1 to 4. The transparent substrate is
Equipped with a transparent conductive film that connects from the front surface to the image acquisition area on the back surface.
The translucent substrate according to any one of claims 1 to 4. A signal reading circuit board, an electron injection blocking reinforcing layer, a crystalline selenium film, a hole injection blocking reinforcing layer, and a translucent substrate that bends along the shape of the signal reading circuit board, in this order.
Junction type solid-state image sensor. The hole injection blocking reinforcing layer is formed of any one of gallium oxide, cerium oxide, germanium dioxide, silicon nitride, and silicon carbide.
The junction type solid-state image sensor according to claim 7. The electron injection blocking reinforcement layer is formed of any one of molybdenum trioxide, nickel oxide, gallium oxide, antimony trisulfide, silicon nitride, and silicon carbide.
The junction type solid-state image sensor according to claim 7.

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