JP5720306B2 - Manufacturing method of solid-state imaging device - Google Patents

Description

  The present disclosure relates to a method for manufacturing a solid-state imaging device in which photoelectric conversion units are arranged on a curved surface curved in three dimensions, a solid-state imaging device obtained by the manufacturing method, and an electronic apparatus including the solid-state imaging device.

  An imaging apparatus such as a camera in which a solid-state imaging element and an imaging lens are combined is configured by arranging an imaging lens on the light receiving surface side of the solid-state imaging element. In such an imaging apparatus, when a subject is imaged by an imaging lens, a focal position shift occurs between the central portion and the peripheral portion of the imaging surface due to lens aberration called curvature of field. Therefore, a configuration has been proposed in which a curved surface that is curved three-dimensionally according to the curvature of field of the imaging lens is formed, and the photoelectric conversion unit is arranged with the curved surface as an imaging surface (light receiving surface) of the solid-state imaging device. . This eliminates the need to correct field curvature (lens aberration) by combining a plurality of lenses. For example, the following two methods are disclosed as a method for manufacturing a solid-state imaging device in which photoelectric conversion units are arranged on such a curved surface.

  The first method is a method using a package body having a curved surface in the element arrangement region and a suction hole formed in the bottom. In this case, the solid-state imaging device is placed facing the curved surface to which the adhesive is applied, and the gap between the solid-state imaging device and the curved surface is reduced through the suction hole so that the solid-state imaging device is in close contact with the curved surface. And fix with a fixing agent (see Patent Document 1 below).

  The second method is a method using a wiring board formed of a material having an opening and a thermal expansion coefficient larger than that of the solid-state imaging device. In this case, first, the wiring board and the solid-state imaging device are joined via the protruding electrodes. The contraction rate of the wiring board becomes larger than the contraction rate of the solid-state image sensor due to the cooling action after heating and cooling, and the solid-state image sensor is bent by applying a compressive force due to the difference in the contraction rate (see Patent Document 2 below). ).

JP 2003-243635 A (particularly paragraphs 0013 to 0014 and FIG. 2) JP 2004-146633 A (particularly paragraphs 0017 to 0020 and FIG. 1)

  However, in any of the first method and the second method described above, the entire chip constituting the solid-state imaging device is curved. For this reason, this is a method in which stress is applied to the peripheral end portion of the chip having a rough surface due to division by dicing, and cracks are likely to occur in the chip from the peripheral end portion side.

  Therefore, the present disclosure aims to provide a method for manufacturing a solid-state imaging device that can leave a flat portion around a curved portion obtained by three-dimensionally bending an imaging region, and thereby hardly cause damage such as cracks. And Furthermore, the present disclosure is a solid-state imaging device obtained by such a manufacturing method, a highly reliable solid-state imaging device that has a three-dimensional curved portion and prevents damage such as cracks, and the solid-state imaging device An object is to provide an electronic device using the element.

  In order to achieve such an object, a method for manufacturing a solid-state imaging device according to the present disclosure includes the following procedure. First, an element chip in which photoelectric conversion parts are arranged on one main surface side is manufactured. In addition, a pedestal is prepared which is made of a material having a larger expansion coefficient than that of the element chip and has an opening and the periphery of the opening is shaped as a flat surface. Then, the pedestal is heated to expand, and the element chip is placed on the flat surface of the pedestal in a state of closing the opening of the pedestal. Thereafter, in a state where the element chip is fixed to the flat surface of the expanded pedestal, the pedestal is cooled and contracted, so that a portion corresponding to the opening in the element chip is curved three-dimensionally.

  According to the manufacturing method described above, in the pedestal, only the center portion of the element chip arranged to close the opening is three-dimensionally curved while the periphery of the element chip is fixed to the flat surface around the opening. For this reason, the peripheral part of the element chip continuing from the peripheral end of the curved part becomes a flat part fixed to the flat surface of the pedestal. Therefore, the peripheral portion of the element chip is left as a flat portion to which no stress due to bending is applied.

  The solid-state imaging device of the present disclosure is arranged on an element chip having a curved portion that is curved in three dimensions and a flat portion that extends from the peripheral end of the curved portion, and on the concave curved surface side of the curved portion of the element chip. And a photoelectric conversion unit.

  The electronic device of the present disclosure is also an electronic device including the solid-state imaging device having such a configuration, and includes an optical system that guides incident light to the photoelectric conversion unit of the solid-state imaging device.

  As described above, according to the present disclosure, it is possible to curve only the central portion in three dimensions while leaving the peripheral portion of the element chip as a flat portion to which stress due to bending is not applied. For this reason, it becomes possible to manufacture a solid-state imaging device having a three-dimensional curved portion at the center of the element chip without causing damage such as cracks. As a result, it is possible to improve the reliability of a solid-state imaging device having a three-dimensional curved portion and an electronic apparatus using the solid-state imaging device.

It is a schematic block diagram of the principal part in the solid-state image sensor obtained by applying this indication. It is sectional drawing and a top view of the base used for the manufacturing method of 1st Embodiment and 2nd Embodiment. It is sectional process drawing which shows the manufacturing method of 1st Embodiment. It is sectional process drawing which shows the manufacturing method of 2nd Embodiment. It is sectional drawing and a top view of the base used for the manufacturing method of 3rd Embodiment. It is sectional process drawing which shows the manufacturing method of 3rd Embodiment. It is sectional drawing and a top view of the base used for the manufacturing method of 4th Embodiment. It is sectional process drawing which shows the manufacturing method of 4th Embodiment. It is a block diagram of the electronic device of this indication.

Hereinafter, embodiments of the present disclosure will be described in the following order based on the drawings.
1. 1. Schematic configuration example of solid-state imaging device of the present disclosure First embodiment (an example in which an element chip is bent by using hardening shrinkage of a resin together)
3. Second Embodiment (Example in which an element chip is bent using gas volume contraction)
4). Third embodiment (example using a pedestal as a package)
5). Fourth Embodiment (Example of fixing an element chip to a pedestal by vacuum suction)
6). Fifth embodiment (embodiment of electronic device)
In addition, in each embodiment and modification, the same code | symbol is attached | subjected to a common component, and the overlapping description is abbreviate | omitted.

<< 1. Schematic configuration example of solid-state image sensor >>
FIG. 1 shows a schematic configuration of a MOS type solid-state imaging device as an example of a solid-state imaging device manufactured by applying the manufacturing method of each embodiment of the present disclosure.

  The solid-state imaging device shown in this figure has an imaging region 4 in which a plurality of pixels 3 including a photoelectric conversion unit are two-dimensionally arranged in the center on the one main surface side of the element chip 2. A pixel circuit composed of a plurality of transistors (so-called MOS transistors) and capacitive elements is connected to each pixel 3 arranged in the imaging region 4 together with a photoelectric conversion unit. Note that some of the pixel circuits may be shared by a plurality of photoelectric conversion units. In this case, the pixel 3 is configured as a unit of a shared pixel structure including a plurality of photoelectric conversion units, a plurality of transfer transistors, one shared floating diffusion, and one other shared pixel transistor. You can also Further, the pixel circuit arranged together with the photoelectric conversion unit in the pixel 3 may be provided on the back surface opposite to the surface on which the photoelectric conversion unit is provided.

  Peripheral circuits such as a vertical drive circuit 5, a column signal processing circuit 6, a horizontal drive circuit 7, and a system control circuit 8 are provided in the peripheral portion of the imaging region 4 as described above.

  The vertical drive circuit 5 is configured by, for example, a shift register, selects a pixel drive line 9 wired to the imaging region 4, supplies a pulse for driving the pixel 3 to the selected pixel drive line 9, and The pixels 3 arranged in 4 are driven in units of rows. That is, the vertical drive circuit 5 selectively scans each pixel 3 arranged in the imaging region 4 in the vertical direction sequentially in units of rows. Then, a pixel signal based on the signal charge generated according to the amount of light received in each pixel 3 is supplied to the column signal processing circuit 6 through the vertical signal line 10 wired perpendicular to the pixel drive line 9.

  The column signal processing circuit 6 is disposed for each column of the pixels 3, for example, and performs signal processing such as noise removal on the signal output from the pixels 3 for one row for each pixel column. That is, the column signal processing circuit 6 performs signals such as correlated double sampling (CDS), signal amplification, and analog / digital conversion (AD) to remove fixed pattern noise unique to a pixel. Process.

  The horizontal drive circuit 7 is configured by, for example, a shift register, and sequentially outputs horizontal scanning pulses, thereby selecting each of the column signal processing circuits 6 in order and outputting a pixel signal from each of the column signal processing circuits 6.

  The system control circuit 8 receives an input clock and data for instructing an operation mode and outputs data such as internal information of the solid-state imaging device 1. That is, in the system control circuit 8, based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock, the clock signal and the control signal that are the reference for the operation of the vertical drive circuit 5, the column signal processing circuit 6, the horizontal drive circuit 7, and the like. Is generated. These signals are input to the vertical drive circuit 5, the column signal processing circuit 6, the horizontal drive circuit 7, and the like.

  The peripheral circuits 5 to 8 as described above and the pixel circuit provided in the imaging region 4 constitute a drive circuit that drives each pixel.

  In addition, in a solid-state imaging device manufactured by applying the manufacturing method of each embodiment of the present disclosure described below, the center portion of the element chip 2 is curved in a three-dimensional manner as described in detail in each embodiment. The unit 11 is configured. The periphery of the curved portion 11 is configured as a flat portion 13 having a flat surface. The imaging region 4 described above is arranged on the concave curved surface side in the bending portion 11. On the other hand, the peripheral circuits 5 to 8 are arranged in the curved portion 11 and the flat portion 13 around the imaging region 4. A part of the peripheral circuits 5 to 8 may be disposed at a position where the peripheral circuits 5 to 8 are stacked on the imaging region 4.

  As a modification of the element chip 2, terminal electrodes (extracted from the pixel circuit of each pixel 3 and the peripheral circuits 5 to 8) are provided on the back surface of the imaging region 4 on the side opposite to the photoelectric conversion unit disposed in each pixel 3. The element chip 2a may be provided with a chip side electrode). In this case, the terminals connected to these drive circuits are drawn out to the opposite side of the surface on which the photoelectric conversion unit is provided via through-chip vias (Through Silicon via: TSV, Through Chip Via: TCV). Note that the solid-state imaging device of the present disclosure can be applied to either a front-illuminated type or a back-illuminated type configuration. That is, in the case of a front-illuminated solid-state imaging device, as shown in the drawing, an imaging region 4 in which pixels including photoelectric conversion units and pixel transistors are arranged is formed on the concave curved surface side of an element chip 2 formed of a semiconductor substrate. The Peripheral circuits 5 to 8 are also formed on the concave curved surface side, a multilayer wiring layer in which a plurality of layers of wirings are arranged via an interlayer insulating film is formed thereon, and a color filter and an on-chip lens are further formed thereon. It is formed. On the other hand, in the case of a back-illuminated solid-state imaging device, an imaging region 4 having a photoelectric conversion portion is formed on the concave curved surface side of the element chip 2 formed of a thinned semiconductor substrate, and a color filter is formed on the concave curved surface side. And an on-chip lens is formed. Further, a pixel transistor and peripheral circuits 5 to 8 are formed on the convex curved surface side opposite to the concave curved surface, and a multilayer wiring layer in which a plurality of layers of wirings are arranged via an interlayer insulating film is formed thereon.

  In the following embodiments, a manufacturing method and a detailed configuration of a solid-state imaging device including such element chips 2 and 2a will be described.

≪2. First Embodiment (an example in which an element chip is bent using volumetric shrinkage of a resin) >>
[Configuration of pedestal used in manufacturing method of first embodiment]
FIG. 2 is a cross-sectional view and a plan view of the base 21 used in the manufacturing method of the first embodiment. The pedestal 21 shown in this figure has an opening 23 in the center. In the opening 23, one surface of the pedestal 21 provided with the opening 23 is shaped as a flat surface 25 around the opening 23.

  The opening 23 has an outer shape that matches the curvature of field (lens aberration) of an optical system that combines a lens and a plurality of lenses that are used in combination with the solid-state imaging device manufactured here. If a lens having a normal outer shape is a circular shape, the opening shape of the opening 23 in a plan view is preferably a circle (perfect circle), and four corners of a square are curved. It may be a shape. Further, the inner wall portion of the opening 23 on the flat surface 25 side has a tapered shape in which the opening diameter increases toward the flat surface 25 side. The angle θ formed by the side wall of the opening 23 and the extended surface of the flat surface 25 is less than θ = 90 °, and is preferably about θ = 45 ° as an example. As described above, it is particularly preferable that the portion where the opening diameter is widened in the opening 23 has a concave curved shape with respect to the flat surface 25. The curvature of curvature is a curvature that matches the curvature of field of an optical system such as a lens used in combination with the element chip (2) described with reference to FIG. Furthermore, it is particularly preferable that the boundary portion from the portion where the opening diameter is widened to the flat surface 25 in the opening 23, that is, the edge portion of the opening 23, is configured as a convex curved surface. Further, the opening width w1 of the opening 23 on the flat surface 25 side (including the portion where the opening diameter is widened) is such that the imaging region (4) of the element chip (2) described with reference to FIG. It is assumed that it is about.

  The flat surface 25 is provided over the entire circumference of the opening 23. The flat surface 25 has a width w2 that supports the periphery of the element chip (2) at a position where at least the imaging region (4) of the element chip (2) described with reference to FIG. have. The entire circumference or a part of the outer periphery of the flat surface 25 may be configured as a surface higher than the flat surface 25 in order to facilitate alignment when the element chip (2) is placed. When such alignment is not necessary, the entire surface of one surface of the base 21 may be a flat surface 25 having the same height.

  The base 21 as described above is provided with a bottom plate 27 for closing the opening 23 on the surface opposite to the side on which the flat surface 25 is provided. The bottom plate 27 may be formed integrally with the pedestal 21 or may be formed separately from the pedestal 21 as long as the opening 23 can be closed in a sealed state. The bottom plate 27 may be configured as a package in which wiring and terminals are formed.

  In particular, the pedestal 21 is configured by using a material having a coefficient of thermal expansion (CTE) larger than that of the element chip (2) as a main constituent member. For example, if the element chip (2) is mainly composed of single crystal silicon (CTE = 2.4), stainless steel (SUS410: CTE = 10.4, SUS304: CTE = 17.3), The pedestal 21 is configured using aluminum (CTE = 23).

[Production Method of First Embodiment]
FIG. 3 is a cross-sectional process diagram illustrating the method for manufacturing the solid-state imaging device of the first embodiment. The manufacturing method of the first embodiment shown in FIG. 3 is a method of manufacturing a solid-state imaging device using the pedestal 21 having the above-described configuration, and the manufacturing method of the first embodiment will be described below based on this drawing.

  First, as shown in FIG. 3A, an uncured resin 31 is filled in the opening 23 of the base 21 whose bottom is closed by the bottom plate 27. The resin 31 is made of, for example, a thermosetting resin, and it is preferable to use a material having a higher cure shrinkage rate than the shrinkage rate of the base 21 due to cooling. The uncured resin 31 used here also acts as an adhesive between the base 21 and the element chip after curing. For example, when the above-described stainless steel or aluminum is used as the constituent material of the pedestal 21, for example, an epoxy resin is used as the resin 31. The resin material can be used with a cure shrinkage of about 1 to 8% or more by adjusting the filler content, for example.

  The filling amount of the resin 31 into the opening 23 is such that it is supplied to the flat surface 25 of the pedestal 21 in advance so that it becomes an adhesive between the element chip and the pedestal 21 to be placed next on the pedestal 21. Suppose that Further, the filling amount of the resin 31 into the opening 23 is such that when the pedestal 21 and the resin 31 are subsequently heated, the uncured resin 31 expands and the resin 31 is also supplied onto the flat surface 25 of the pedestal 21. It may be a degree.

  Next, as illustrated in FIG. 3B, the element chip 2 is placed on the flat surface 25 of the pedestal 21 in a state where the opening 23 of the pedestal 21 is closed. At this time, the imaging region 4 is placed in the range of the opening 23 with the formation surface of the imaging region 4 in the element chip 2 (ie, the formation surface of the photoelectric conversion unit) facing upward. Further, the periphery of the imaging region 4 is supported by the flat surface 25 of the pedestal 21 over the entire circumference. In this state, the peripheral circuits 5 to 8 arranged around the imaging region 4 may be arranged corresponding to the flat surface 25 and a part thereof may be arranged within the range of the opening 23. When the uncured resin 31 is supplied on the flat surface 25 of the pedestal 21, the uncured resin 31 is sandwiched between the flat surface 25 of the pedestal 21 and the element chip 2 as an adhesive. Let

  Next, as shown in FIG. 3C, the pedestal 21 is heated and expanded. Furthermore, if necessary, the bottom plate 27 is also heated to expand the bottom plate 27 to the same extent as the base 21. Thereby, the base 21 is expanded, the diameter of the opening 23 is expanded, and the flat surface 25 is expanded outward. Further, due to heat conduction from the base 21 and the bottom plate 27, the uncured resin 31 filled in the opening 23 is also heated and expands. When the element chip 2 is placed directly on the flat surface 25 of the pedestal 21, the resin 31 is placed between the flat surface 25 of the pedestal 21 and the element chip 2 due to the expansion of the uncured resin 31. The uncured resin 31 is sandwiched between the flat surface 25 of the pedestal 21 and the element chip 2 as an adhesive.

  In this state, the resin 31 is heated to a temperature at which the element chip 2 is not affected and the resin 31 is cured, and the resin 31 is cured. For example, when the above-described epoxy resin is used as the resin 31, heating is performed at 160 ° C. for about 1 hour. The element chip 2 is fixed to the flat surface 25 of the base 21 by such curing of the resin 31. At this time, it is important that the entire periphery of the periphery of the element chip 2 is fixed to the flat surface 25.

  In addition, as long as the adhesive action of the resin 31 is obtained before the curing of the resin 31 is completed, the procedure of placing the element chip 2 on the pedestal 21 after heating the pedestal 21 may be used. In this case, first, the resin 31 is filled into the opening 23 of the base 21, and then the base 21 is heated to expand the resin 31 together with the base 21. Next, the element chip 2 is placed on the pedestal 21 before the resin 31 is cured, and then the resin 31 is heated to a temperature where the element chip 2 is not affected and until the resin 31 is cured. The resin 31 is heated to cure the resin 31.

  After the above, as shown in FIG. 3D, the pedestal 21 and the bottom plate 27 are cooled from the heated state to room temperature with the element chip 2 fixed to the flat surface 25 of the pedestal 21. Thereby, the resin 31 filled in the opening 23 of the base 21 is also cooled to room temperature. In the process of cooling, the base 21, the bottom plate 27, and the cured resin 31 contract. At this time, the base 21 and the bottom plate 27 contract to the size before heating. Further, the cured resin 31 undergoes further curing shrinkage than the uncured state before heating.

  Due to the shrinkage of the pedestal 21 and the resin 31, the central portion of the element chip 2 arranged corresponding to the opening 23 of the pedestal 21 is pulled toward the inside of the opening 23 filled with the resin 31, and the tertiary It is shaped as a curved portion 11 that is originally curved. The curved shape of the curved portion 11 is a shape that follows the inner wall shape of the opening 23 on the flat surface 25 side of the pedestal 21. Then, like the planar shape of the opening 23 of the pedestal 21, for example, it is shaped into a shape having a circular bottom. Further, if the shape of the opening 23 is a shape in which four corners of a square are curved, a three-dimensional curve having a circular bottom at a portion close to the top of the bending portion 11 is formed. At this time, by fixing the entire circumference of the periphery of the element chip 2 to the flat surface 25, stress due to curing shrinkage of the resin 31 and stress due to contraction of the base 21 are applied to the central portion of the element chip 2 corresponding to the opening 23. Can be added evenly. Thereby, the curved part 11 curved in three dimensions can be formed without generating "wrinkles".

  In order to sufficiently fix the entire circumference of the periphery of the element chip 2 to the flat surface 25, the outer shape of the element chip 2 is maintained so that the flat portion 13 is maintained to have a width larger than a certain level. It is important to adjust the width w1 of the opening 23. As an example, if the shape of the element chip 2 is an outer shape of 4 mm × 4 mm and a thickness of about 15 μm, the flat part 13 is set to be left with a width of 0.3 mm or more on the entire circumference of the element chip 2.

  Further, the inner wall of the opening 23 of the pedestal 21 has a tapered shape, and the edge portion of the opening 23 has a convex curved surface, so that stress at the time of bending is concentrated on the element chip 2 portion corresponding to the edge of the opening 23. It is possible to prevent the element chip 2 from cracking at this portion.

  On the other hand, the periphery of the bending portion 11 in the element chip 2 is fixed to the flat surface 25 of the pedestal 21 and is not curved, and remains as the flat portion 13. The flat portion 13 is left over the entire circumference of the bending portion 11.

  The curved portion 11 formed on the element chip 2 preferably has a curvature that matches the curvature of field of an optical system such as a lens used in combination with the element chip 2, and is about 10% to 20%, for example, 17 as an example. % Curvature. The shape of the curved portion 11 is controlled mainly by the shape of the inner wall of the opening 23 on the flat surface 25 side. The curvature of the curved portion 11 is adjusted by filling the inside of the opening 23 with the shape of the inner wall of the opening 23 on the flat surface 25 side, the expansion coefficient of the pedestal 21, the volume shrinkage rate (curing shrinkage rate) when the resin 31 is cured. It is adjusted by the volume of the resin 31. If it is desired to increase the curvature of the bending portion 11, the pedestal 21 is made of a material having a large expansion coefficient of the pedestal 21, or a resin 31 having a high curing shrinkage rate is used, or the volume of the opening 23 is increased to increase the opening 23. The volume of the resin 31 filled in is increased. These are used in combination as appropriate.

  Further, the thickness of the element chip 2 may be adjusted in order to bend the element chip 2 in a three-dimensional manner having a desired curvature without difficulty. For this reason, it is preferable to make the thickness of the element chip 2 smaller as the bottom area of the bending portion 11 is smaller than when the bottom area of the bending portion 11 is large.

  As described above, the solid-state imaging device 1-1 having the curved portion 11 is formed. After the solid-state imaging device 1 is formed, the pedestal 21 and the resin 31 may be thinned from the back side as necessary. If the shape of the curved portion 11 can be maintained, the element chip 2 may be peeled off from the base 21 and the resin 31 to form the solid-state imaging device 1-1. In order to facilitate such peeling of the element chip 2, a release agent may be applied to the back surface of the element chip 2 (the surface facing the pedestal 21) before placing the element chip 2 on the pedestal 21. good. Further, for fixing the pedestal 21 and the element chip 2, a thermosetting resin 31 filled in the opening 23 was used as an adhesive. However, for fixing the pedestal 21 and the element chip 2, in addition to the resin 31, a photocurable resin may be used as an adhesive in the opening 23. In this case, the element chip 2 is placed on the flat surface 25 of the expanded pedestal 21 while sandwiching an adhesive made of a photocurable resin that is cured by irradiation with long wavelength light. In this state, the adhesive is cured by light irradiation with a wavelength that transmits the element chip 2, and the fixing is performed. As an example, if the element chip 2 is made of single crystal silicon, light irradiation using long wavelength light with a wavelength of about 700 nm or more is performed. Accordingly, the adhesive is cured by the long wavelength light that has passed through the element chip 2 and reached the photocurable resin.

[Solid-state imaging device of first embodiment]
As shown in FIG. 1, the solid-state imaging device 1-1 obtained by the above procedure is configured as a curved portion 11 in which the central portion of the device chip 2 is curved three-dimensionally. Moreover, the flat part 13 extended from the peripheral part of this curved part 11 is provided. The flat portion 13 is disposed on the entire circumference of the bending portion 11 and constitutes the same surface.

  An imaging region 4 in which photoelectric conversion units are arranged is disposed on the concave curved surface side of the curved portion 11. Such a curved portion 11 has such a curvature that the photoelectric conversion unit is arranged along the curvature of field in accordance with the curvature of field of an optical system such as a lens used in combination with the solid-state imaging device 1-1. Suppose that there is. For this reason, it is preferable that the bottom surface of the bending part 11 is circular.

  The flat portion 13 is provided with peripheral circuits 5 to 8 arranged around the imaging region 3. The peripheral circuits 5 to 8 may be disposed on the flat portion 13 and a part thereof may be disposed on the bending portion 11. The flat portion 13 is provided with terminals drawn from the peripheral circuits 5 to 8 and can be connected to an external circuit by using the terminals. At this time, since the terminals are provided on the flat portion 13, good workability for connection to an external circuit such as bonding is ensured. However, the terminals drawn out from the peripheral circuits 5 to 8 are not limited to being provided in the flat portion 13, and may be arranged in the bending portion 11, and further drawn out to the convex curved surface side in the bending portion 11. Also good.

  Further, in the solid-state imaging device 1-1, the pedestal 21 is bonded to the convex curved surface side of the bending portion 11 of the element chip 2 in a state where the bending portion 11 of the element chip 2 is inserted into the opening 23 of the pedestal 21 described above. Has been. The element chip 2 and the pedestal 21 are fixed around the entire circumference of the curved portion 11 with the resin 31 sandwiched between the flat surface 25 and the element chip 2 as an adhesive. The opening 23 of the pedestal 21 is filled with a resin 31, and the shape of the curved portion 11 is secured by the resin 31.

[Effect of the first embodiment]
According to the first embodiment as described above, in the pedestal 21, in the state where the periphery of the element chip 2 is fixed to the flat surface 25 around the opening 23, the center of the element chip 2 arranged by closing the opening 23 is arranged. Only the part is curved in three dimensions. The peripheral portion of the element chip 2 that continues from the peripheral end of the bending portion 11 formed by the bending is left as the flat portion 13 that is fixed to the flat surface 25 of the base 21. Therefore, it is possible to leave the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied.

  Further, when the element chip 2 is bent, the pedestal 21 contracts, so that compressive stress is applied to the element chip 2 fixed to the pedestal 21. At the same time, tensile stress is applied to the central portion of the element chip 2 due to the curing shrinkage of the resin 31 filled in the opening 23 of the base 21. Thereby, the compressive stress and the tensile stress applied to the element chip 2 cancel each other, and the element chip 2 can be bent without stress.

  Further, the curvature of the curved portion 11 includes the inner wall shape of the opening 23 on the flat surface 25 side of the pedestal 21, the expansion coefficient of the pedestal 21, the cure shrinkage rate of the resin 31 filling the opening 23, and the volume of the resin 31 (opening 23 The volume can be adjusted. For this reason, it is possible to control the shape and curvature of the bending portion 11 with high accuracy and over a wide range.

  As described above, according to the first embodiment, it is possible to leave the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied, and to form only the central portion as the three-dimensional curved portion 11. . For this reason, it becomes possible to manufacture the solid-state image sensor 1-1 provided with the three-dimensional curved part 11 without generating damage, such as a crack. As a result, it is possible to improve the reliability of the solid-state imaging device 1-1 including the three-dimensional curved portion 11.

≪3. Second Embodiment (an example in which an element chip is curved using gas volume contraction) >>
[Configuration of Pedestal Used for Manufacturing Method of Second Embodiment]
The pedestal used in the manufacturing method of the second embodiment is the same as the pedestal 21 described with reference to FIG. 2 in the first embodiment.

[Manufacturing Method of Second Embodiment]
FIG. 4 is a cross-sectional process diagram illustrating a method for manufacturing the solid-state imaging device of the second embodiment. The manufacturing method of 2nd Embodiment shown in FIG. 4 is a manufacturing method of the solid-state image sensor using the base 21 of the said structure, and a manufacturing method is demonstrated based on this figure below.

  First, as shown in FIG. 4A, a bottom plate 27 is arranged on the side opposite to the side where the flat surface 25 is provided in the base 21, and the opening 23 of the base 21 is closed from one side.

  Next, as shown in FIG. 4B, the base 21 is heated and expanded. Furthermore, if necessary, the bottom plate 27 is also heated to expand the bottom plate 27 to the same extent as the base 21. Thereby, the base 21 is expanded, the diameter of the opening 23 is expanded, and the flat surface 25 is expanded outward. The heating temperature at this time is set to a range which is not less than the curing temperature of the adhesive provided on the back surface of the element chip (2) described below and does not affect the element chip (2).

  Next, as shown in FIG. 4C, in a state where the opening 23 of the pedestal 21 is closed, the formation surface of the imaging region 4 (that is, the formation surface of the photoelectric conversion unit) in the element chip 2 is directed upward, and on the flat surface 25 of the pedestal 21. The element chip 2 is placed. An adhesive 35 made of, for example, a thermosetting resin is disposed on the mounting surface side of the element chip 2 on the base 21. As shown in the figure, the adhesive 35 may be disposed on the entire surface of the element chip 2 on the mounting surface side of the pedestal 21 or only on the periphery of the element chip 2 corresponding to the flat surface 25 of the pedestal 21. May be. However, it is important that the adhesive 35 is sandwiched between the flat surface 25 of the pedestal 21 and the element chip 2 on the entire circumference surrounding the opening 23.

  At this time, the imaging region 4 is placed in the range of the opening 23, and the periphery of the imaging region 4 is supported by the flat surface 25 of the pedestal 21 through the adhesive 35. Further, in this state, the peripheral circuits 5 to 8 arranged around the imaging region 4 are arranged corresponding to the flat surface 25 and a part thereof may be arranged within the range of the opening 23 as described above. This is the same as in the first embodiment.

  In this state, the adhesive 35 sandwiched between the flat surface 25 of the pedestal 21 and the element chip 2 is maintained until it is cured, and the element chip 2 is fixed on the flat surface 25 of the pedestal 21. At this time, it is important to fix the entire periphery of the periphery of the element chip 2 to the flat surface 25. For example, if an epoxy resin is used as the adhesive 35, the temperature is about 160 ° C. for about 15 minutes. Thus, the opening 23 of the heated pedestal 21 is sealed by the element chip 2 and the bottom plate 27.

  Next, as shown in FIG. 4D, the base 21 and the bottom plate 27 are cooled from the heated state to room temperature, and the gas in the opening 23 of the base 21 sealed by the bottom plate 27 and the element chip 2 is also cooled to room temperature. . In this cooling process, the gas in the pedestal 21, the bottom plate 27, and the opening 23 contracts. At this time, the base 21 and the bottom plate 27 contract to the size before heating.

  Due to the volumetric contraction of the gas in the pedestal 21 and the opening 23, the central portion of the element chip 2 corresponding to the opening 23 of the pedestal 21 is pulled toward the inside of the opening 23 and curved in three dimensions. The curved portion 11 is shaped. The curved shape of the curved portion 11 is a shape that follows the inner wall shape of the opening 23 on the flat surface 25 side of the pedestal 21. Then, like the planar shape of the opening 23 of the pedestal 21, for example, it is shaped into a shape having a circular bottom. Further, if the shape of the opening 23 is a shape in which four corners of a square are curved, a three-dimensional curve having a circular bottom at a portion close to the top of the bending portion 11 is formed. At this time, by fixing the entire circumference of the periphery of the element chip 2 to the flat surface 25, stress due to curing shrinkage of the resin 31 and stress due to contraction of the base 21 are applied to the central portion of the element chip 2 corresponding to the opening 23. Can be added evenly. Thereby, the curved part 11 curved in three dimensions can be formed without generating "wrinkles". For this reason, it is important that the entire circumference of the periphery of the element chip 2 is sufficiently fixed to the flat surface 25 by adjusting the width w1 of the opening 23 with respect to the outer shape of the element chip 2. This is the same as in the first embodiment.

  The inner wall of the opening 23 of the pedestal 21 has a tapered shape, and the edge portion of the opening 23 has a convex curved surface, so that the force during bending is concentrated on the element chip 2 portion corresponding to the edge of the opening 23. As in the first embodiment, the element chip 2 can be prevented from cracking at this portion.

  Further, in the element chip 2, the peripheral portion of the bending portion 11 is fixed to the flat surface 25 of the pedestal 21 and is not bent, and remains as the flat portion 13. The flat portion 13 is also left over the entire circumference of the bending portion 11 as in the first embodiment.

  Similar to the first embodiment, the bending portion 11 formed on the element chip 2 has a curvature that matches the curvature of field of an optical system such as a lens used in combination with the element chip 2. The shape of the curved portion 11 is controlled mainly by the shape of the inner wall of the opening 23 on the flat surface 25 side. The curvature of the curved portion 11 is adjusted by adjusting the shape of the inner wall of the opening 23 on the flat surface 25 side and the expansion coefficient of the pedestal 21, and further by adjusting the volume of the opening 23. If it is desired to increase the curvature of the bending portion 11, the base 21 is made of a material having a large expansion coefficient of the base 21, or the volume of the opening 23 is increased to increase the volume of gas sealed in the opening 23. Let These are used in combination as appropriate.

  When the adjustment of the curvature of the curved portion 11 is insufficient with only the expansion coefficient of the base 21 and the volume of the opening 23, an exhaust system 37 for exhausting the inside of the opening 23 is provided to cool the base 21 to room temperature. Alternatively, the gas in the opening 23 may be exhausted by the exhaust system 37. As another method, there is a method using a vacuum chamber. In this case, the element chip 2 is placed on the pedestal 21 in the vacuum chamber, and the inside of the opening 23 of the pedestal 21 is also decompressed by depressurizing the vacuum chamber. The element chip 2 is attached to the base 21 expanded in this state, and the inside of the opening 23 is sealed. Thereafter, the pedestal 21 and the element chip 2 are released into the atmosphere, so that the element chip 2 is bent toward the opening 23 of the pedestal 21. Note that the thickness of the element chip 2 may be adjusted in order to bend the element chip 2 in a three-dimensional manner having a desired curvature without difficulty, as in the first embodiment.

  As described above, the solid-state imaging device 1-2 having the curved portion 11 is formed. After forming the solid-state imaging device 1-2, the pedestal 21 may be thinned from the back side as necessary. Further, in order to stabilize the shape of the curved portion 11, the opening 23 may be filled with resin after the bottom plate 27 is removed and cured. On the other hand, the element chip 2 may be peeled from the pedestal 21 if the shape of the curved portion 11 can be maintained. In order to facilitate such peeling of the element chip 2, a release agent may be applied to the back surface of the element chip 2 (the surface facing the pedestal 21) before placing the element chip 2 on the pedestal 21. good. In addition, as in the first embodiment, a photocurable resin may be used as an adhesive for fixing the pedestal 21 and the element chip 2.

[Solid-State Image Sensor of Second Embodiment]
The solid-state imaging device 1-2 obtained by the above-described procedure has a space in the opening 23 of the base 21 in the solid-state imaging device of the first embodiment. Furthermore, in the manufacturing process, the solid-state imaging device 1-2 formed by exhausting or depressurizing the inside of the opening 23 and leaving the bottom plate 27 as a package remains in a space in the opening 23 maintained in a reduced pressure atmosphere. . However, when resin is filled in the opening 23 of the pedestal 21, the same as the solid-state imaging device of the first embodiment is obtained.

[Effects of Second Embodiment]
According to the second embodiment as described above, as in the first embodiment, in the pedestal 21, the periphery of the element chip 2 is fixed to the flat surface 25 around the opening 23 and the opening 23 is blocked. Only the central part of the arranged element chip 2 is curved in three dimensions. A peripheral edge portion continuous from the peripheral end of the bending portion 11 formed by this bending is left as the flat portion 13 fixed to the flat surface 25 of the base 21. Therefore, it is possible to leave the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied.

  Further, when the element chip 2 is bent, the pedestal 21 contracts, so that compressive stress is applied to the element chip 2 fixed to the pedestal 21. At the same time, tensile stress is applied to the central portion of the element chip 2 due to the volumetric contraction of the gas in the opening 23 of the base 21. As a result, as in the first embodiment, the compressive stress and the tensile stress applied to the element chip 2 by bending cancel each other, and the element chip 2 can be bent without stress.

  The curvature (shape) of the curved portion 11 is such that the inner wall shape of the opening 23 on the flat surface 25 side of the pedestal 21, the expansion coefficient of the pedestal 21, the volume of gas sealed in the opening 23 (volume of the opening 23), Can be adjusted by exhausting the gas in the opening 23 from the exhaust system 37. For this reason, it is possible to control the curvature of the bending part 11 in a wide range with high accuracy.

  As described above, according to the second embodiment, it is possible to form the three-dimensional curved portion 11 only at the central portion while leaving the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied. . For this reason, it becomes possible to manufacture the solid-state imaging device 1-2 including the three-dimensional curved portion 11 without causing damage such as cracks. As a result, similar to the first embodiment, it is possible to improve the reliability of the solid-state imaging device 1-2 including the three-dimensional curved portion 11.

<< 4. Third Embodiment (Example Using Pedestal as Package) >>
[Configuration of Pedestal Used for Manufacturing Method of Third Embodiment]
FIG. 5 is a cross-sectional view and a plan view of a pedestal used in the manufacturing method of the third embodiment. The pedestal 21a shown in this figure is different from the pedestal used in the manufacturing method of the first embodiment and the second embodiment in that the pedestal 21a functions as a package, and the flat surface 25 side is covered with an insulating film 41. In addition, a pedestal side electrode 43 is provided.

  That is, the pedestal 21a is a flat surface in which the pedestal 21 used in the manufacturing method of the first and second embodiments is the pedestal main body 21, and the flat surface 25 side is covered with the insulating film 41 and further covered with the insulating film 41. In this configuration, the pedestal electrode 43 is disposed on the surface 25. The pedestal side electrode 43 is disposed corresponding to a chip side electrode provided in an element chip to be described next, and is disposed in a state of being embedded in the insulating film 41. That is, the surface of the pedestal side electrode 43 constitutes a part of the flat surface 25 together with the insulating film 41. Such a pedestal side electrode 43 is pulled out from the flat surface 25 of the pedestal 21a and further connected to an external member. The pedestal side electrode 43 may be provided on the inner wall of the opening 13 on the flat surface 25 side.

[Manufacturing Method of Third Embodiment]
FIG. 6 is a cross-sectional process diagram illustrating a method for manufacturing the solid-state imaging device of the third embodiment. The manufacturing method of the third embodiment shown in FIG. 6 is a method of manufacturing a solid-state imaging device using the pedestal 21a having the above configuration, and the manufacturing method will be described below with reference to this drawing.

  First, as shown in FIG. 6A, the bottom plate 27 is arranged on the side opposite to the side where the flat surface 25 is provided in the base 21a, and the opening 23 of the base 21a is closed from one side.

  Next, as shown to FIG. 6B, the base 21a is heated and expanded. Furthermore, if necessary, the bottom plate 27 is also heated, so that the bottom plate 27 is expanded to the same extent as the base 21a. Thereby, the base 21a is expanded, the diameter of the opening 23 is expanded, and the flat surface 25 is expanded outside. The heating temperature at this time is not less than the curing temperature of the adhesive provided on the back surface of the element chip (2a) described below and does not affect the element chip (2a).

  Next, as shown in FIG. 6C, the element chip 2a is placed on the pedestal 21a expanded by heating. The element chip 2a used here includes a chip-side electrode 15 on the back side opposite to the surface on which the imaging region 4 and the peripheral circuits 5 to 8 are provided. These chip side electrodes 15 are drawn from the imaging region 4 and the peripheral circuits 5 to 8, and are arranged at positions corresponding to the pedestal side electrode 43, for example, at a peripheral portion of the element chip 2 a. Further, an anisotropic conductive adhesive 45 is disposed on the arrangement surface side of the chip side electrode 15 in such an element chip 2a. As illustrated, the anisotropic conductive adhesive 45 may be disposed on the entire surface of the chip-side electrode 15 on the element chip 2a, or the peripheral edge of the element chip 2a corresponding to the flat surface 25 of the base 21a. You may arrange only. However, it is important that the anisotropic conductive adhesive 45 is sandwiched between the flat surface 25 of the base 21a and the element chip 2a on the entire circumference surrounding the opening 23.

  The element chip 2a as described above is on the flat surface 25 of the pedestal 21a with the formation surface of the imaging region 4 (that is, the formation surface of the photoelectric conversion unit) facing upward in the element chip 2a in a state of closing the opening 23 of the pedestal 21a. Placed on. Thus, the anisotropic conductive adhesive 45 is sandwiched between the flat surface 25 of the base 21a and the element chip 2a.

  At this time, the pedestal 21a is arranged so that the chip side electrode 15 provided on the element chip 2a and the pedestal side electrode 43 provided on the flat surface 25 of the pedestal 21a expanded by heating are opposed to each other at 1: 1. The element chip 2a is aligned with respect to. Further, the imaging region 4 of the element chip 2a is placed in the range of the opening 23 of the pedestal 21a, and the peripheral portion of the imaging region 4 is supported by the flat surface 25 of the pedestal 21a through the anisotropic conductive adhesive 45. Further, in this state, the peripheral circuits 5 to 8 arranged around the imaging region 4 are arranged on the flat surface 25 and a part thereof may be arranged within the range of the opening 23. It is the same.

  When the anisotropic conductive adhesive 45 is, for example, a material in which conductive fine particles are dispersed in a thermosetting resin, the anisotropic conductive adhesive 45 is provided between the flat surface 25 of the base 21a and the element chip 2a. The element chip 2a is fixed on the flat surface 25 of the base 21a while maintaining the sandwiched state. At this time, it is important to fix the entire periphery of the periphery of the element chip 2 a to the flat surface 25. For example, when an epoxy resin is used for the anisotropic conductive adhesive 45, the temperature is about 160 ° C. for about 15 minutes. As described above, the opening 23 of the heated pedestal 21 a is sealed by the element chip 2 a and the bottom plate 27. Further, the base side electrode 43 and the chip side electrode 15 are connected by the anisotropic conductive adhesive 45.

  Next, as shown in FIG. 6D, the pedestal 21a and the bottom plate 27 are cooled from the heated state to room temperature, and the gas in the opening 23 of the pedestal 21a sealed by the bottom plate 27 and the element chip 2a is also cooled to room temperature. . In this cooling process, the gas in the pedestal 21a, the bottom plate 27, and the opening 23 contracts. At this time, the base 21a and the bottom plate 27 contract to the size before heating.

  Due to the volumetric contraction of the gas in the pedestal 21a and the opening 23, the central portion of the element chip 2a disposed corresponding to the opening 23 of the pedestal 21a is pulled toward the inside of the opening 23 and curved in a three-dimensional manner. The curved portion 11 is shaped. The curved shape of the curved portion 11 is a shape that follows the inner wall shape of the opening 23 on the flat surface 25 side of the pedestal 21a. Then, similarly to the planar shape of the opening 23 of the pedestal 21a, for example, it is shaped into a shape having a circular bottom. Further, if the shape of the opening 23 is a shape in which four corners of a square are curved, a three-dimensional curve having a circular bottom at a portion close to the top of the bending portion 11 is formed. Further, as in the other embodiments, a photocurable resin may be used as an adhesive (an anisotropic conductive adhesive) for fixing the pedestal 21a and the element chip 2a. In this case, an anisotropic conductive adhesive 45 in which conductive fine particles are dispersed in a photocurable resin is used.

  The inner wall of the opening 23 of the pedestal 21a is tapered, and the edge portion of the opening 23 is a convex curved surface, so that the bending force is concentrated on the element chip 2a corresponding to the edge of the opening 23. It is possible to prevent the cracking of the element chip 2a at this portion, as in the other embodiments.

  Further, in the element chip 2a, the peripheral portion of the bending portion 11 is fixed to the flat surface 25 of the pedestal 21a and is not bent, and remains as the flat portion 13. The flat portion 13 is left over the entire circumference of the curved portion 11 as in the other embodiments.

  The curved portion 11 formed in the element chip 2a has a curvature matching the curvature of field of an optical system such as a lens used in combination with the element chip 2a, as in the other embodiments. Such adjustment of the curvature is the same as in the second embodiment, and is mainly adjusted by the shape of the inner wall of the opening 23 on the flat surface 25 side and the expansion coefficient of the pedestal 21a, and further adjusted by the volume of the opening 23. Further, in order to sufficiently adjust the curvature, the gas in the opening 23 may be exhausted by the exhaust system 37 when the pedestal 21a is cooled to room temperature, and a method of releasing it to the atmosphere after pasting in a reduced pressure state. As in the second embodiment, these may be combined. Further, the thickness of the element chip 2a may be adjusted in order to bend the element chip 2a in a three-dimensional manner having a desired curvature without difficulty.

  As described above, the solid-state imaging device 1-3 having the curved portion 11 is formed. After the formation of the solid-state image sensor 1-3, the pedestal 21a may be thinned from the back side as necessary. Further, in order to stabilize the shape of the curved portion 11, the opening 23 may be filled with resin after the bottom plate 27 is removed and cured.

[Solid-State Image Sensor of Third Embodiment]
The solid-state imaging device 1-3 obtained by the above procedure is obtained by bonding the above-described pedestal 21a as a package to the convex curved surface side of the bending portion 11 in the element chip 2a. The element chip 2a is obtained by providing a chip-side electrode 15 with respect to the element chip (2) of the solid-state imaging element (1-1) of the first embodiment. The chip-side electrode 15 is disposed on the back side opposite to the surface on which the imaging region 4 and the peripheral circuits 5 to 8 are provided in the flat portion 13, with respect to the pedestal-side electrode 43 disposed on the pedestal 21 a configured as a package. Are connected 1: 1. The chip-side electrode 15 and the pedestal-side electrode 43 are connected by an anisotropic conductive adhesive 45 sandwiched between the flat surface 25 of the pedestal 21a and the element chip 2a. Further, in the solid-state imaging device 1-3 formed by exhausting or depressurizing the inside of the opening 23 and leaving the bottom plate 27 as a package in the manufacturing process, the space in the opening 23 is maintained in a decompressed atmosphere.

[Effect of the third embodiment]
Even in the third embodiment as described above, as in the other embodiments, in the pedestal 21a, the opening 23 is closed with the peripheral edge of the element chip 2a fixed to the flat surface 25 around the opening 23. Only the central part of the element chip 2a arranged in (3) is curved three-dimensionally. A peripheral edge portion continuous from the peripheral end of the bending portion 11 formed by this bending is left as the flat portion 13 fixed to the flat surface 25 of the base 21a. Therefore, it is possible to leave the peripheral portion of the element chip 2a as the flat portion 13 to which no stress due to bending is applied.

  Further, when the element chip 2a is bent, compressive stress is applied to the element chip 2a fixed to the pedestal 21a by contracting the pedestal 21a. At the same time, tensile stress is applied to the central portion of the element chip 2a due to the volumetric contraction of the gas in the opening 23 of the base 21a. As a result, as in the other embodiments, the compressive stress and the tensile stress applied to the center of the element chip 2a due to bending cancel each other, and the element chip 2a can be bent without stress.

  The curvature of the curved portion 11 can be adjusted by the expansion coefficient of the pedestal 21a, the volume of gas sealed in the opening 23 (volume of the opening 23), and the exhaust of gas in the opening 23 from the exhaust system 37. . For this reason, it is possible to control the curvature of the bending part 11 in a wide range with high accuracy.

  As described above, according to the third embodiment, it is possible to leave only the central portion as the three-dimensional curved portion 11 while leaving the peripheral portion of the element chip 2a as the flat portion 13 to which stress due to bending is not applied. . For this reason, it is possible to manufacture the solid-state imaging device 1-3 including the three-dimensional curved portion 11 without causing damage such as cracks. As a result, as in the other embodiments, it is possible to improve the reliability of the solid-state imaging device 1-3 including the three-dimensional curved portion 11.

  Furthermore, according to the third embodiment, by using the base 21a as a package, it is possible to reduce the process of assembling the element chip 2a and the package with the base-side electrode 43 as an external terminal. Further, a terminal drawn from the peripheral circuits 5 to 8 can be provided on the surface side of the flat portion 13 of the element chip 2a on which the imaging region 4 is arranged, and connection to an external circuit can be achieved using this terminal. At this time, since the terminals are provided on the flat portion 13, good workability for connection to an external circuit such as bonding is ensured.

  The third embodiment can also be combined with the method for forming a curved portion by curing shrinkage of the resin described in the first embodiment. In this case, an anisotropic conductive adhesive having curing shrinkage is used as the resin used in the first embodiment.

≪5. Fourth Embodiment (Example of fixing an element chip to a pedestal by vacuum suction) >>
[Configuration of Pedestal Used for Manufacturing Method of Fourth Embodiment]
FIG. 7 is a sectional view and a plan view of a pedestal used in the manufacturing method of the fourth embodiment. The difference between the pedestal 21b shown in FIG. 7 and the pedestal used in the manufacturing method of the first and second embodiments is that the pedestal 21b includes an exhaust groove 51 for fixing the element chip. The other configurations are the same.

  That is, this pedestal 21 b has the pedestal 21 used in the manufacturing method of the first embodiment and the second embodiment as the pedestal main body 21, and has an exhaust groove 51 on the flat surface 25. The exhaust groove 51 is provided so as to surround the entire periphery of the opening 23 in the base 21b. An exhaust system 53 is connected to the exhaust groove 51 so that the gas in the exhaust groove 51 is exhausted.

[Manufacturing Method of Fourth Embodiment]
FIG. 8 is a cross-sectional process diagram illustrating a method for manufacturing the solid-state imaging device of the fourth embodiment. The manufacturing method of the fourth embodiment shown in FIG. 8 is a method of manufacturing a solid-state imaging device using the pedestal 21b having the above configuration, and the manufacturing method will be described below with reference to this drawing.

  First, as shown in FIG. 8A, the bottom plate 27 is disposed on the side opposite to the side where the flat surface 25 is provided in the base 21b, and the opening 23 of the base 21b is closed from one side.

  Next, as shown to FIG. 8B, the base 21b is heated and expanded. Further, if necessary, the bottom plate 27 is also heated to expand the bottom plate 27 to the same extent as the base 21b. Thereby, the base 21b is expanded, the diameter of the opening 23 is expanded, and the flat surface 25 is expanded outside. The heating temperature at this time is in a range that does not affect the element chip (2) described below, and is, for example, 300 ° C. or less.

  Next, as shown in FIG. 8C, in a state in which the opening 23 of the pedestal 21b is closed, the formation surface of the imaging region 4 (that is, the formation surface of the photoelectric conversion unit) in the element chip 2 is directed upward, and on the flat surface 25 of the pedestal 21b. The element chip 2 is placed. At this time, the imaging region 4 is placed within the range of the opening 23, and the peripheral portion of the imaging region 4 is supported by the flat surface 25 of the base 21b. Further, the entire surface of the exhaust groove 51 provided on the flat surface 25 of the base 21 b is closed by the element chip 2. Further, in this state, the peripheral circuits 5 to 8 arranged around the imaging region 4 are arranged on the flat surface 25 and a part thereof may be arranged within the range of the opening 23. It is the same as the form.

  In this state, the gas in the exhaust groove 51 is exhausted by the exhaust system 53, the pressure in the exhaust groove 51 is reduced, and the element chip 2 is fixed to the flat surface 25 of the base 21b expanded by heating by vacuum suction. At this time, it is important to fix the entire periphery of the periphery of the element chip 2 to the flat surface 25. Thereby, the opening 23 of the heated pedestal 21 b is sealed by the element chip 2 and the bottom plate 27.

  Next, as shown in FIG. 8D, while the element chip 2 is fixed to the pedestal 21b, the pedestal 21b and the bottom plate 27 are cooled from the heated state to room temperature, and the pedestal sealed by the bottom plate 27 and the element chip 2 is sealed. The gas in the opening 23 of 21b is also cooled to room temperature. In this cooling process, the gas in the base 21b, the bottom plate 27, and the opening 23 contracts. At this time, the base 21b and the bottom plate 27 contract to the size before heating.

  Due to the volumetric contraction of the gas in the pedestal 21 b and the opening 23, the central portion of the element chip 2 is pulled toward the inside of the opening 23 and shaped as the curved portion 11 that is curved in three dimensions. The curved shape of the curved portion 11 is a shape that follows the inner wall shape of the opening 23 on the flat surface 25 side of the base 21b. Then, similarly to the planar shape of the opening 23 of the pedestal 21b, for example, it is shaped into a shape having a circular bottom. Further, if the shape of the opening 23 is a shape in which four corners of a square are curved, a three-dimensional curve having a circular bottom at a portion close to the top of the bending portion 11 is formed. At this time, since the entire periphery of the periphery of the element chip 2 is fixed to the flat surface 25 by vacuum suction, the stress due to the volumetric contraction of the gas in the opening 23 is applied to the central portion of the element chip 2 corresponding to the opening 23. The stress due to the contraction of the base 21b can be applied evenly. Thereby, the curved part 11 curved in three dimensions can be formed without generating "wrinkles". For this reason, it is important that the entire circumference of the periphery of the element chip 2 is sufficiently fixed to the flat surface 25 by adjusting the width w1 of the opening 23 with respect to the outer shape of the element chip 2. This is the same as the embodiment.

  The inner wall of the opening 23 of the pedestal 21b is tapered, and the edge portion of the opening 23 is a convex curved surface, so that the bending force is concentrated on the element chip 2 corresponding to the edge of the opening 23. As in the other embodiments, it is possible to prevent the element chip 2 from being cracked at this portion.

  Further, in the element chip 2, the peripheral portion of the bending portion 11 is fixed to the flat surface 25 of the pedestal 21 b and is not bent, and remains as the flat portion 13. The flat portion 13 is left over the entire circumference of the curved portion 11 as in the other embodiments.

  The curved portion 11 formed on the element chip 2 has a curvature that matches the curvature of field of an optical system such as a lens used in combination with the element chip 2 as in the other embodiments. Such adjustment of the curvature is the same as in the second and third embodiments, and is mainly adjusted by the shape of the inner wall of the opening 23 on the flat surface 25 side and the expansion coefficient of the pedestal 21b. Adjusted by. Further, in order to sufficiently adjust the curvature, the gas in the opening 23 may be exhausted by the exhaust system 37 when the pedestal 21b is cooled to room temperature, and a method of releasing it into the atmosphere after bonding in a reduced pressure state. These may be combined in the same manner as in the second and third embodiments. Further, the thickness of the element chip 2 may be adjusted in order to bend the element chip 2 in a three-dimensional manner having a desired curvature without difficulty.

  As described above, the solid-state imaging device 1-4 having the curved portion 11 is formed. After the formation of the solid-state imaging device 1-4, in order to further stabilize the shape of the bending portion 11, the bottom plate 27 is removed and the opening 23 is filled with resin in a state where the element chip 2 is vacuum-adsorbed on the base 21b. Then, the base 21b and the element chip 2 may be integrated. In this case, after the base 21b and the element chip 2 are integrated, the base 21b may be thinned from the back side. On the other hand, if the shape of the curved portion 11 can be maintained, it is not necessary to integrate the element chip 2 and the base 21b, and the element chip 2 may be removed from the base 21b and used as a solid-state imaging element.

[Solid-State Image Sensor of Fourth Embodiment]
The solid-state imaging device 1-4 obtained by the above procedure is configured as a curved portion 11 in which the central portion of the element chip 2 is curved in three dimensions. Moreover, the flat part 13 extended from the peripheral part of this curved part 11 is provided. The flat portion 13 is disposed on the entire circumference of the bending portion 11 and constitutes the same surface.

  An imaging region 4 in which photoelectric conversion units are arranged is disposed on the concave curved surface side of the curved portion 11. Such a bending portion 11 has such a curvature that the photoelectric conversion portion is arranged along the curvature of field in accordance with the curvature of field of an optical system such as a lens used in combination with the solid-state imaging device 1-4. Suppose that there is. For this reason, it is preferable that the bottom surface of the bending part 11 is circular.

  The flat portion 13 is provided with peripheral circuits 5 to 8 arranged around the imaging region 4. A part of the peripheral circuits 5 to 8 may be arranged in the bending portion 11. The flat portion 13 is provided with terminals drawn from the peripheral circuits 5 to 8 and can be connected to an external circuit by using the terminals. At this time, since the terminals are provided on the flat portion 13, good workability for connection to an external circuit such as bonding is ensured as in the other embodiments.

  Further, the solid-state imaging device 1-4 has a configuration in which the element chip 2 is supported from the convex curved surface side of the bending portion 11 by the pedestal 21b and the opening 23 of the pedestal 21b is filled with resin. In this case, the shape of the bending portion 11 is secured by the resin filled in the opening 23.

[Effect of Fourth Embodiment]
Even in the fourth embodiment as described above, similarly to the other embodiments, in the pedestal 21b, the opening 23 is blocked in a state where the periphery of the element chip 2 is fixed to the flat surface 25 around the opening 23. Only the central part of the element chip 2 arranged in (3) is curved three-dimensionally. A peripheral edge portion continuous from the peripheral end of the bending portion 11 formed by this bending is left as the flat portion 13 fixed to the flat surface 25 of the pedestal 21b. Therefore, it is possible to leave the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied.

  Further, when the element chip 2 is bent, compressive stress is applied to the element chip 2 fixed to the pedestal 21b by contracting the pedestal 21b. At the same time, tensile stress is applied to the central portion of the element chip 2 due to the volumetric contraction of the gas in the opening 23 of the base 21b. As a result, similarly to the other embodiments, the compressive stress and the tensile stress applied to the center of the element chip 2 due to bending cancel each other, and the element chip 2 can be bent without stress.

  The curvature of the curved portion 11 is such that the inner wall shape of the pedestal 21b on the flat surface 25 side, the expansion coefficient of the pedestal 21b, the volume of gas sealed in the opening 23 (volume of the opening 23), and the opening from the exhaust system 37 The gas can be adjusted by exhausting the gas in the gas tank 23. For this reason, it is possible to control the curvature of the bending part 11 in a wide range with high accuracy.

  As described above, according to the fourth embodiment, it is possible to form only the central portion as the three-dimensional curved portion 11 while leaving the peripheral portion of the element chip 2 as the flat portion 13 to which no stress due to bending is applied. . For this reason, it becomes possible to manufacture the solid-state imaging device 1-4 including the three-dimensional curved portion 11 without causing damage such as cracks. As a result, as in other embodiments, it is possible to improve the reliability of the solid-state imaging device 1-4 including the three-dimensional curved portion 11.

  In the first to fourth embodiments described above, the element chip having the MOS type solid-state imaging element is applied. However, the present disclosure can be applied to an element chip having a CCD type solid-state imaging element. Both the MOS type solid-state imaging device and the CCD type solid-state imaging device can be applied to the back side illumination type or the front side illumination type. In the embodiment of the present disclosure, when an imaging chip having a back-illuminated MOS solid-state imaging device is used, it is preferable that a light receiving area can be increased and sensitivity can be further improved.

≪6. Fifth embodiment (embodiment of electronic device) >>
The solid-state imaging device according to the present disclosure described in each of the embodiments described above is an electronic device such as a camera system such as a digital camera or a video camera, a mobile phone having an imaging function, or another device having an imaging function. Can be applied to.

  FIG. 9 is a configuration diagram of a camera using a solid-state imaging device as an example of the electronic apparatus according to the present disclosure. The camera according to the present embodiment is an example of a video camera capable of capturing still images or moving images. The camera 91 according to this embodiment includes a solid-state image sensor 1, an optical system 93 that guides incident light to a light receiving sensor unit of the solid-state image sensor 1, a shutter device 94, and a drive circuit 95 that drives the solid-state image sensor 1. And a signal processing circuit 96 that processes an output signal of the solid-state imaging device 1.

  The solid-state imaging device 1 is applied with the solid-state imaging device (1-1 to 1-4) including the three-dimensional curved portion described in the above-described embodiments. The optical system 93 may be an optical lens system including a plurality of optical lenses or a single optical lens. Here, since a solid-state imaging device (1-1 to 1-4) having a three-dimensional curved portion along the curvature of field of the optical system 93 is used as the solid-state imaging device 1, an optical lens constituting the optical system 93 is used. May be a small number. Such an optical system 93 is disposed on the concave curved surface side of the curved portion of the element chip in which the imaging region is provided in the solid-state imaging device 1, and the curved portion of the element chip along the curvature of field of the optical system 93. A concave curved surface is arranged. As a result, image light (incident light) from the subject is imaged on the imaging surface (imaging region) of the solid-state imaging device 1 and signal charges are accumulated in the solid-state imaging device 1 for a certain period.

  The shutter device 94 controls the light irradiation period and the light shielding period to the solid-state imaging device 1. The drive circuit 95 supplies a drive signal for controlling the transfer operation of the solid-state imaging device 1 and the shutter operation of the shutter device 94. Signal transfer of the solid-state imaging device 1 is performed by a drive signal (timing signal) supplied from the drive circuit 95. The signal processing circuit 96 performs various signal processing. The video signal subjected to the signal processing is stored in a storage medium such as a memory or output to a monitor.

  According to the electronic apparatus according to the present embodiment described above, as described in the first to fourth embodiments described above, the solid-state imaging device that includes the three-dimensional curved portion and does not generate cracks is used. Therefore, it is possible to improve the reliability of an electronic device using this solid-state imaging device.

In addition, this technique can also take the following structures.
(1)
Producing an element chip in which photoelectric conversion portions are arranged on one main surface side;
Providing a pedestal that is configured using a material having a larger expansion coefficient than the element chip and has an opening and the periphery of the opening is shaped as a flat surface;
Heating and expanding the pedestal;
Placing the element chip on a flat surface of the pedestal in a state of closing the opening of the pedestal;
Solid-state imaging, including cooling and contracting the pedestal in a state where the element chip is fixed to the flat surface of the expanded pedestal, thereby bending the portion corresponding to the opening in the element chip in three dimensions Device manufacturing method.

(2)
The element chip is fixed to the flat surface of the expanded pedestal over the entire circumference of the opening. (1).

(3)
The method for manufacturing a solid-state imaging device according to (1) or (2), wherein the opening of the pedestal has a circular opening shape on the flat surface side.

(4)
On one main surface of the element chip, a peripheral circuit is provided around an imaging region in which the photoelectric conversion unit is provided,
In the step of placing the element chip on the flat surface of the pedestal, the imaging region is disposed within the range of the opening. (1) to (3).

(5)
Before placing the element chip on the flat surface of the pedestal, the opening is filled with uncured resin,
When placing the element chip on the flat surface of the pedestal, the element chip is placed on the flat surface of the pedestal with one main surface side on which the photoelectric conversion units are arranged facing upward.
When the pedestal is cooled and contracted, the element chip is bent toward the opening side by volume contraction due to cooling of the resin. (Manufacturing of the solid-state imaging device according to any one of (1) to (4)) Method.

(6)
When placing the element chip on the flat surface of the pedestal, the element chip is placed on the flat surface of the pedestal with one main surface side on which the photoelectric conversion units are arranged facing upward.
When the pedestal is cooled and contracted, the element chip is curved toward the opening side by sealing the inside of the opening and cooling the gas in the opening to contract the volume (1) to ( 4) The manufacturing method of the solid-state image sensor in any one of.

(7)
The method for manufacturing a solid-state imaging device according to any one of (1) to (6), wherein the opening of the pedestal has a shape in which an opening diameter increases toward a flat surface on which the element chip is placed.

(8)
The solid surface of the solid imaging device according to any one of (1) to (7), wherein the flat surface of the pedestal and the element chip are fixed by an adhesive sandwiched between the flat surface of the pedestal and the element chip. Production method.

(9)
The flat surface of the pedestal is provided with an exhaust groove communicating with the outside of the pedestal,
When the element chip is fixed on the flat surface of the pedestal, the element chip is vacuum-sucked on the flat surface of the pedestal by suction from the exhaust groove (1) to (7). Manufacturing method of solid-state image sensor.

(10)
In the element chip, a chip side electrode is disposed on a surface facing the pedestal,
A pedestal side electrode is disposed on the flat surface of the pedestal,
When fixing the element chip on the flat surface of the pedestal, the chip-side electrode and the pedestal side are held by sandwiching an anisotropic conductive adhesive between the flat surface of the pedestal and the element chip. The method for manufacturing a solid-state imaging device according to any one of (1) to (7), wherein the electrode is connected.

(11)
An element chip having a curved portion that is curved three-dimensionally and a flat portion extending from the peripheral end of the curved portion;
A solid-state imaging device comprising: a photoelectric conversion unit arranged on the concave curved surface side of the curved portion in the element chip.

(12)
The flat part in the said element chip is arrange | positioned at the perimeter of the curved part in the said element chip, and comprises the same surface. (11).

(13)
The solid-state imaging device according to (11) or (12), wherein a bottom surface of the curved portion is circular.

(14)
The solid-state imaging device according to any one of (11) to (13), wherein a peripheral circuit is disposed around an imaging region in which the photoelectric conversion units are arranged in the element chip.

(15)
It is configured using a material having a larger expansion coefficient than the element chip, and includes a base that has an opening and is shaped as a flat surface around the opening,
The solid portion according to any one of (11) to (14), wherein the flat portion of the element chip is fixed to the flat surface of the pedestal in a state where the curved portion of the element chip is inserted into the opening of the pedestal. Image sensor.

(16)
The solid-state imaging device according to (15), wherein an opening of the pedestal is filled with resin.

(17)
The solid-state imaging device according to (15) or (16), wherein the opening of the pedestal has a shape in which an opening diameter increases toward a flat surface on which the element chip is placed.

(18)
The solid-state image sensor according to any one of (15) to (17), wherein an adhesive is sandwiched between the flat surface of the pedestal and the element chip.

(19)
In the element chip, a chip side electrode is disposed on a surface facing the pedestal,
A pedestal side electrode is disposed on the flat surface of the pedestal,
An anisotropic conductive adhesive that connects the chip-side electrode and the pedestal-side electrode is sandwiched between the flat surface of the pedestal and the element chip. (15) to (17) Solid-state image sensor.

(20)
An element chip having a curved portion that is curved three-dimensionally and a flat portion extending from the peripheral end of the curved portion;
A photoelectric conversion part arranged on the concave curved surface side of the curved part in the element chip;
An electronic apparatus comprising: an optical system that guides incident light to the photoelectric conversion unit.

DESCRIPTION OF SYMBOLS 1,1-1, 1-2, 1-3, 1-4 ... Solid-state image sensor, 2, 2a ... Element chip, 3 ... Pixel (photoelectric conversion part), 4 ... Imaging region, 11 ... Curved part, 13 ... Flat part, 15 ... chip side electrode, 21, 21a, 21b ... pedestal, 23 ... opening, 25 ... flat surface, 31 ... resin (adhesive), w1 ... opening diameter, 35 ... adhesive, 43 ... pedestal side electrode, 45 ... Anisotropic conductive adhesive, 51 ... Exhaust groove, 93 ... Optical system, 91 ... Electronic equipment.

Claims (9)

Producing an element chip in which photoelectric conversion portions are arranged on one main surface side;
Providing a pedestal that is configured using a material having a larger expansion coefficient than the element chip and has an opening and the periphery of the opening is shaped as a flat surface;
Heating and expanding the pedestal;
Placing the element chip on a flat surface of the pedestal in a state of closing the opening of the pedestal;
By contracting to cool the pedestal in a state of fixing the device chip to the flat surface of the pedestal which is the expansion, seen including a possible curving the portion corresponding to the opening in the device chip in three dimensions,
The opening of the pedestal is a method for manufacturing a solid-state imaging device having a shape in which the opening diameter increases toward a flat surface on which the element chip is placed . The method of manufacturing a solid-state imaging element according to claim 1, wherein the element chip is fixed to the flat surface of the expanded pedestal over the entire circumference of the opening. The method for manufacturing a solid-state imaging device according to claim 1, wherein the opening of the pedestal has a circular opening shape on the flat surface side. On one main surface of the element chip, a peripheral circuit is provided around an imaging region in which the photoelectric conversion unit is provided,
The method for manufacturing a solid-state imaging device according to any one of claims 1 to 3 , wherein in the step of placing the element chip on a flat surface of the pedestal, the imaging region is disposed within the range of the opening. Before placing the element chip on the flat surface of the pedestal, the opening is filled with uncured resin,
When placing the element chip on the flat surface of the pedestal, the element chip is placed on the flat surface of the pedestal with one main surface side on which the photoelectric conversion units are arranged facing upward.
Wherein when the base is cooled to contract, the method for manufacturing the solid-state imaging device according to the device chip by curing shrinkage of the resin to claim 1-4 curving toward the opening side. When placing the element chip on the flat surface of the pedestal, the element chip is placed on the flat surface of the pedestal with one main surface side on which the photoelectric conversion units are arranged facing upward.
When shrinking by cooling the pedestal claim 1-4 for curving the element chip toward the opening side by volume to cool the gas in the opening to seal the inside of the opening contraction The manufacturing method of the solid-state image sensor in any one of . And the device chip and the flat surface of the pedestal, a method for manufacturing a solid-state imaging device according to any one of claims 1 to 6 for fixing the adhesive is sandwiched between the flat surface and the device chip of the base . The flat surface of the pedestal is provided with an exhaust groove communicating with the outside of the pedestal,
The solid-state imaging according to any one of claims 1 to 6 , wherein when the element chip is fixed on the flat surface of the pedestal, the element chip is vacuum-sucked to the flat surface of the pedestal by suction from the exhaust groove. Device manufacturing method. In the element chip, a chip side electrode is disposed on a surface facing the pedestal,
A pedestal side electrode is disposed on the flat surface of the pedestal,
When fixing the element chip on the flat surface of the pedestal, the chip-side electrode and the pedestal side are held by sandwiching an anisotropic conductive adhesive between the flat surface of the pedestal and the element chip. The manufacturing method of the solid-state image sensor in any one of Claims 1-6 which connects an electrode.

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