Imaging module

Abstract

To provide a technique for suppressing damage to an image sensor chip when the image sensor chip is curved along a three-dimensional curved surface.SOLUTION: An imaging module includes a base member (20) including a concave portion (22) that is concavely curved in a cross section along a first direction and concavely curved in a cross section along a second direction perpendicular to the first direction, and an image sensor chip (30) fixed to the concave portion in a curved state along the surface of the concave portion. The image sensor chip includes an image sensor area (32) in which an image sensor is provided, and an outer peripheral area (34) arranged around the image sensor area. A wavy portion (38) in which the image sensor chip is curved in a wavy manner is provided in a part of the outer peripheral area.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to an imaging module.

[0002] Patent Document 1 discloses a technology in which an imaging element chip is attached to a curved recess, thereby fixing the imaging element chip in a spherically curved state. By curving the imaging element chip in this way, aberrations can be suppressed, and the number of imaging lenses can be reduced. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-045151 Summary of the Invention [Problem to be solved by the invention]

[0004] When an imaging element chip is curved along a three-dimensional curved surface such as a spherical surface, high stress is applied to a certain region of the imaging element chip. In particular, when the radius of curvature of the three-dimensional curved surface is reduced to more effectively suppress aberration, particularly high stress is applied to a certain region of the imaging element chip. When high stress is applied to a certain region of the imaging element chip in this way, the imaging element chip may bend or break in that region. This specification proposes a technology for suppressing damage to the imaging element chip when the imaging element chip is curved along a three-dimensional curved surface. [Means for solving the problem]

[0005] The imaging module disclosed in this specification includes a base member having a recess that is concavely curved in a cross section along a first direction and also concavely curved in a cross section along a second direction perpendicular to the first direction, and an imaging element chip fixed to the recess in a state where the imaging element chip is curved along the surface of the recess. The imaging element chip has an imaging element region where an image sensor is provided and an outer peripheral region disposed around the imaging element region. A wavy portion where the imaging element chip is curved in a wavy shape is provided in a part of the outer peripheral region.

[0006] In this imaging module, the recess of the base member is concavely curved in a cross section along a first direction and also concavely curved in a cross section along a second direction perpendicular to the first direction. That is, the surface of the recess is a three-dimensional curved surface. Furthermore, the imaging element chip is fixed to the recess in a state curved along the surface of the recess. A wavy portion in which the imaging element chip is curved in a wavy manner is provided in the peripheral region of the imaging element chip. Since the wavy portion is provided in the peripheral region, imaging can be performed preferably in the imaging element region. Furthermore, the provision of the wavy portion prevents large stress from being applied to the imaging element chip in portions other than the wavy portion. This prevents damage to the imaging element chip in portions other than the wavy portion. Furthermore, since the imaging element chip is curved in a wavy manner at the wavy portion, bending of the imaging element chip is prevented. Therefore, damage to the imaging element chip at the wavy portion is suppressed. In this way, according to the structure of this imaging module, damage to the imaging element chip can be suppressed when the imaging element chip is bent along a three-dimensional curved surface. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5]3 is a cross-sectional view taken along line VV in FIG. 2. [Figure 6] FIG. 10 is an explanatory diagram showing a process of attaching an imaging element chip to a recess. [Figure 7] FIG. 4 is a cross-sectional view showing a modified example of the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing another modified example of the first embodiment. [Figure 9] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] In an example imaging module disclosed in the present specification, the imaging element chip may have a rectangular outer shape, and the wavy portion may be provided in a range including a center portion of at least one of four sides of the rectangle.

[0009] When the external shape of the imaging element chip is rectangular, high compressive stress is likely to occur in the center of each side of the rectangle. By providing the wavy portion in a range that includes the center of at least one of the four sides as described above, damage to the imaging element chip can be effectively suppressed.

[0010] In an example imaging module disclosed in the present specification, the imaging element chip may have a rectangular outer shape, and the wavy portion may be provided in a range including a center portion of at least one of two long sides of the rectangle.

[0011] When the external shape of the imaging element chip is rectangular, particularly high compressive stress is likely to occur in the center of each long side of the rectangle. By providing the wavy portion in a range including the center of at least one of the two long sides as described above, damage to the imaging element chip can be effectively suppressed.

[0012] The imaging module according to the example disclosed in the present specification may further include an adhesive layer that adheres the imaging element chip to the recess. The corrugated portion may not be adhered to the recess.

[0013] With this configuration, the portion of the imaging element chip that is not bonded to the recess can be deformed without being constrained by the recess, so that the imaging element chip can be curved in a wavy shape at that portion without bending, thereby forming a wavy portion.

[0014] In the imaging module according to the example disclosed in the present specification, a hole or a depression may be provided in a portion of the surface of the recess that faces the wavy portion.

[0015] In one example of the imaging module disclosed in the present specification, the imaging module may further include an adhesive layer that adheres the imaging element chip to the recess. The surface of the recess may have a wavy surface that is curved in a wavy manner. The wavy portion may be adhered to the wavy surface by the adhesive layer in a wavy curved state along the wavy surface.

[0016] According to this configuration, the imaging element chip can be bent in a wavy shape along the wavy surface to form the wavy portion.

[0017] In the imaging module disclosed in the present specification as an example, an electrode pad may be provided on a surface of the outer peripheral region of the imaging element chip other than the wavy portion.

[0018] This configuration allows wiring to be suitably connected to the electrode pads. [Example]

[0019] The imaging module 10 of the first embodiment shown in FIG. 1 includes a base member 20 and an imaging element chip 30. The base member 20 is a plate-shaped member. The base member 20 may be made of a metal such as aluminum, or may be made of a resin or the like. A recess 22 is provided on the upper surface of the base member 20. The recess 22 has a concavely curved surface. The surface of the recess 22 is a three-dimensional curved surface. That is, the surface of the recess 22 is concavely curved in a cross section along the x direction, and is also concavely curved in a cross section along the y direction (i.e., a direction perpendicular to the x direction). For example, the surface shape of the recess 22 may be spherical or aspherical (e.g., the surface shape of an ellipsoid, the surface shape of a solid of revolution with a predetermined digraph curve, etc.). The imaging element chip 30 is a semiconductor chip that captures images. The imaging element chip 30 is disposed in the recess 22. The imaging element chip 30 is attached to the surface of the recess 22.

[0020] As shown in FIG. 2, when the imaging module 10 is viewed from above, the imaging element chip 30 has a rectangular outer shape. A long side 30a of the rectangular outer shape of the imaging element chip 30 extends along the x direction, and a short side 30b of the rectangle extends along the y direction. The imaging element chip 30 has an imaging element region 32 and a peripheral region 34. When viewed from above, the imaging element chip 30 has the imaging element region 32 disposed at the center of the imaging element chip 30, and the peripheral region 34 disposed around the imaging element region 32. An image sensor such as a CCD image sensor (Charge Coupled Device image sensor) or a CMOS image sensor (Complementary Metal Oxide Semiconductor image sensor) is provided in the imaging element region 32. An image is captured by the imaging element region 32. No image sensor is provided in the peripheral region 34. A plurality of electrode pads 36 are provided on the surface of the peripheral region 34. Although not shown, wiring such as bonding wires is connected to each electrode pad 36.

[0021] 3 and 4, the surface of the recess 22 is concavely curved in both a cross section along the x direction and a cross section along the y direction. An adhesive layer 40 is provided between the image sensor chip 30 and the surface of the recess 22. The adhesive layer 40 is made of a hardened adhesive. The adhesive layer 40 bonds the image sensor chip 30 to the surface of the recess 22. The adhesive layer 40 fixes the image sensor chip 30 to the surface of the recess 22 in a curved state along the surface of the recess 22.

[0022] As shown in FIG. 2, a wavy portion 38 is provided in the outer peripheral region 34. The wavy portion 38 is a portion where the imaging element chip 30 is curved in a wavy shape. The adhesive layer 40 is not provided below the wavy portion 38, but is provided over the entire lower area of ​​the imaging element chip 30 except for the portion below the wavy portion 38. The entire imaging element region 32 is fixed to the surface of the recess 22 by the adhesive layer 40 in a curved state that follows the surface of the recess 22. The entire outer peripheral region 34 except for the wavy portion 38 is fixed to the surface of the recess 22 by the adhesive layer 40 in a curved state that follows the surface of the recess 22.

[0023] As shown in FIG. 2, the corrugated portion 38 is provided in a range including the center of each of the four rectangular sides of the imaging element chip 30. That is, the imaging element chip 30 has a corrugated portion 38a provided in a range including the center of the two long sides 30a and a corrugated portion 38b provided in a range including the center of the two short sides 30b. FIG. 5 shows a cross section taken along line VV in FIG. 2. That is, FIG. 5 shows a longitudinal cross section of the corrugated portion 38a taken along the x-direction. As shown in FIG. 5, a through hole 20a is provided in the base member 20. The through hole 20a is located below the corrugated portion 38a. The through hole 20a opens to the surface of the recess 22 below the corrugated portion 38a. As described above, the adhesive layer 40 is not provided below the corrugated portion 38a. Therefore, the corrugated portion 38a is not constrained by the adhesive layer 40. As described above, the image sensor chip 30 is curved in a wave-like manner in the wave-like portion 38a. That is, in the wave-like portion 38a, the image sensor chip 30 is repeatedly curved up and down. The wave-like portion 38a is a portion distorted in a wave-like manner by compressing the outer peripheral region 34 in the x direction near the long side 30a. Therefore, in the wave-like portion 38a, the image sensor chip 30 is curved in a wave-like manner in a cross section along the x direction. The longitudinal cross section of the wave-like portion 38b in the y direction has the same structure as the cross section of the wave-like portion 38a in the x direction (i.e., FIG. 5). That is, the through-hole 20a is provided below the wave-like portion 38b, and the adhesive layer 40 is not provided below the wave-like portion 38b. The wave-like portion 38b is a portion distorted in a wave-like manner by compressing the outer peripheral region 34 in the y direction near the short side 30b. Therefore, in the wave-like portion 38b, the image sensor chip 30 is curved in a wave-like manner in a cross section along the y direction.

[0024] Next, a manufacturing method of the imaging module 10 will be described. In the manufacturing process of the imaging module 10, as shown in FIG. 6, the imaging element chip 30 having a flat, uncurved shape is attached to the surface of the recess 22. More specifically, first, an adhesive (i.e., an adhesive layer 40 before hardening) is applied to the underside of the imaging element chip 30 or the surface of the recess 22. At this time, the adhesive is applied so that the adhesive is not placed under the areas of the imaging element chip 30 where the corrugated portions 38 are to be formed (i.e., the areas around the centers of the long sides 30a and the short sides 30b), but is placed under the other areas of the imaging element chip 30. Next, as shown in FIG. 6, the imaging element chip 30 is pressed toward the surface of the recess 22 while heating the base member 20 and the imaging element chip 30. The application of pressure causes the imaging element chip 30 to curve along the surface of the recess 22. The heating also hardens the adhesive. As a result, the imaging element chip 30 is adhered to the surface of the recess 22 by the adhesive layer 40 in a state where it is curved along the surface of the recess 22. Thereafter, wire bonding is performed on each electrode pad 36, and the imaging module 10 is completed.

[0025] When the imaging element chip 30 is pressed against the surface of the recess 22 (i.e., when the imaging element chip 30 is bent along the surface of the recess 22), compressive stress is applied to the outer peripheral region 34 of the imaging element chip 30. More specifically, stress that compresses the outer peripheral region 34 in the x direction is applied near the long sides 30a, and stress that compresses the outer peripheral region 34 in the y direction is applied near the short sides 30b. In particular, high compressive stress occurs around the centers of the long sides 30a and the short sides 30b. As described above, no adhesive is applied to the regions around the centers of the long sides 30a and the short sides 30b. Therefore, the regions around the centers of the long sides 30a and the short sides 30b can be distorted by the compressive stress without being restrained by the adhesive. In the regions where no adhesive is applied, the outer peripheral region 34 is distorted so as to evenly distribute the stress, resulting in a wavy curve of the outer peripheral region 34. As a result, a wavy portion 38a is formed around the center of the long side 30a, and a wavy portion 38b is formed around the center of the short side 30b. In this way, when a region not constrained by adhesive is provided in the peripheral region 34, the peripheral portion can bend in a wavy shape without bending within this region. Therefore, damage to the imaging element chip 30 within this region (i.e., the region where the wavy portion 38 is formed) can be suppressed. Furthermore, by forming the wavy portions 38a and 38b, stress generated in the imaging element chip 30 outside the wavy portions 38a and 38b can be alleviated. This suppresses damage to the imaging element chip 30 outside the wavy portions 38a and 38b. Furthermore, outside the wavy portions 38a and 38b, the imaging element chip 30 can be curved along the surface of the recess 22. Because the wavy portion 38 is not formed within the imaging element region 32, the image sensor within the imaging element region 32 can capture images appropriately. In particular, since the entire imaging element region 32 is curved so as to fit closely to the surface of the recess 22, aberrations can be suppressed when capturing an image. Furthermore, since the electrode pads 36 are provided outside the wavy portions 38a, 38b, bonding wires can be suitably connected to the electrode pads 36.

[0026] In Example 1, through holes 20a were provided below the wavy portion 38 (i.e., the portion of the surface of the recess 22 facing the wavy portion 38). However, as shown in FIG. 7, depressions 20b may be provided in the portion of the surface of the recess 22 facing the wavy portion 38. In this way, even if depressions 20b are provided instead of through holes 20a, the wavy portion 38 can be suitably formed. Also, as shown in FIG. 8, through holes or depressions do not have to be provided below the wavy portion 38. Even if through holes or depressions are not provided below the wavy portion 38, the wavy portion 38 will not be constrained by the adhesive layer 40 if there is no adhesive layer 40 below the wavy portion 38. Therefore, in the process of adhering the imaging element chip 30, the outer peripheral region 34 can be curved in a wavy shape in the region where no adhesive is applied, and the wavy portion 38 can be suitably formed. [Example]

[0027] The image sensor module of Example 2 differs from Example 1 in the structure of the wavy portion 38. The other configurations of the image sensor module of Example 2 are the same as those of the image sensor module of Example 1. As shown in FIG. 9 , in the image sensor module of Example 2, a wavy surface 20c in which the surface of the recess 22 is curved in a wavy shape is provided below the wavy portion 38. Furthermore, in the image sensor module of Example 2, an adhesive layer 40 is provided below the wavy portion 38. Therefore, the wavy portion 38 is adhered to the wavy surface 20c by the adhesive layer 40. The wavy portion 38 is fixed to the wavy surface 20c in a curved state along the wavy surface 20c.

[0028] A manufacturing method of the imaging element module of Example 2 will be described. In the manufacturing method of Example 2, an adhesive is applied to the lower surface of the imaging element chip 30 or the surface of the recess 22 over the entire lower area of ​​the imaging element chip 30. Next, as shown in FIG. 6, the imaging element chip 30 is pressed toward the recess 22 while the base member 20 and the imaging element chip 30 are heated. As a result, the imaging element chip 30 is fixed to the surface of the recess 22 by the adhesive layer 40 in a state where the imaging element chip 30 is curved along the surface of the recess 22. Thereafter, wire bonding is performed on the electrode pads 36, thereby completing the imaging element module of Example 2.

[0029] In the manufacturing method of Example 2, high compressive stress is also applied to the outer peripheral region 34 around the central portions of each side 30a, 30b, forming a wavy portion 38 in the outer peripheral region 34. At this time, since the wavy surface 20c is provided at the lower portion of the central portions of each side 30a, 30b, the outer peripheral region 34 curves in a wavy shape along the wavy surface 20c. Therefore, the wavy portion 38 having the structure shown in FIG. 9 is formed.

[0030] According to the structure of Example 2, the shape of the wavy portion 38 can be made to match the wavy surface 20c of the base member 20. Therefore, by setting the curvature of the wavy surface 20c to a curvature that does not cause damage at the wavy portion 38, it is possible to prevent damage to the image sensor chip 30 at the wavy portion 38. Furthermore, by forming the wavy portion 38 in the outer peripheral region 34, it is possible to reduce stress generated in parts other than the wavy portion 38, and it is possible to prevent damage to the image sensor chip 30 at parts other than the wavy portion 38. In this way, the structure of Example 2 also makes it possible to prevent damage to the image sensor chip 30.

[0031] In the first and second embodiments, the wavy portion 38 is provided in a range including the center of the long side 30a and a range including the center of the short side 30b. However, it is sufficient that the wavy portion 38 is provided in a range including the center of at least one of the four sides 30a, 30b. Because high compressive stress is likely to occur in the center of the sides 30a, 30b, providing the wavy portion 38 in a range including the center of either side can prevent damage to the image sensor chip 30 at that center. Because higher compressive stress is likely to occur in the center of the long side 30a than in the center of the short side 30b, if the wavy portion 38 is provided only on a portion of the four sides 30a, 30b, it is preferable to provide the wavy portion 38 in a range including the center of the long side 30a. Furthermore, even if the image sensor chip 30 has a square outer shape, the wavy portion can be provided in a range including all or part of the centers of the four sides. Furthermore, if high stress occurs in the peripheral region 34 of the imaging element chip 30 in areas other than the center of each side, a wavy portion may be provided in that position.

[0032] The configurations of the imaging modules disclosed in this specification are listed below. (Configuration 1) An imaging module, a base member (20) having a recess (22) that is concavely curved in a cross section along a first direction and that is concavely curved in a cross section along a second direction perpendicular to the first direction; an imaging element chip (30) fixed in the recess in a curved state along the surface of the recess; and The imaging element chip is an imaging element area (32) in which an image sensor is provided; a peripheral region (34) disposed around the imaging element region; and The imaging module has a wavy portion (38) in which the imaging element chip is curved in a wavy shape provided in a part of the outer peripheral region. (Configuration 2) The imaging element chip has a rectangular outer shape, The wavy portion is provided in a range including the center of at least one of the four sides (30a, 30b) of the rectangle. The imaging module according to configuration 1. (Configuration 3) The imaging element chip has a rectangular outer shape, The wavy portion is provided in a range including the center of at least one of the two long sides (30a) of the rectangle. 3. The imaging module according to configuration 2. (Configuration 4) The imaging device further includes an adhesive layer (40) that adheres the imaging element chip to the recess, the undulations are not bonded to the recesses; The imaging module according to any one of configurations 1 to 3. (Configuration 5) The imaging module according to configuration 4, wherein a hole (20a) or a depression (20b) is provided in a portion of the surface of the recess facing the wavy portion. (Configuration 6) an adhesive layer that adheres the imaging element chip to the recess; The surface of the recess has a wavy surface (20c) that is curved in a wavy manner, the wavy portion is adhered to the wavy surface by the adhesive layer in a state where the wavy portion is curved in a wavy shape along the wavy surface; The imaging module according to any one of configurations 1 to 3. (Configuration 7) 7. The imaging module according to any one of configurations 1 to 6, wherein an electrode pad (36) is provided on the surface of the area other than the wavy portion in the outer peripheral area of ​​the imaging element chip.

[0033] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0034] 10: imaging module, 20: base member, 22: recess, 30: imaging element chip, 32: imaging element region, 34: outer peripheral region, 38: wavy portion, 40: adhesive layer

Claims

1. An imaging module, a base member (20) having a recess (22) that is concavely curved in a cross section along a first direction and that is concavely curved in a cross section along a second direction perpendicular to the first direction; an imaging element chip (30) fixed in the recess in a curved state along the surface of the recess; and The imaging element chip is an imaging element area (32) in which an image sensor is provided; a peripheral region (34) arranged around the imaging element region; and The imaging module has a wavy portion (38) in which the imaging element chip is curved in a wavy shape provided in a part of the outer peripheral region.

2. The imaging element chip has a rectangular outer shape, The wavy portion is provided in a range including a central portion of at least one of the four sides (30a, 30b) of the rectangle. The imaging module according to claim 1 .

3. The imaging element chip has a rectangular outer shape, The wavy portion is provided in a range including the center of at least one of the two long sides (30a) of the rectangle. The imaging module according to claim 2 .

4. The imaging device further includes an adhesive layer (40) that adheres the imaging element chip to the recess, the undulations are not bonded to the recesses; The imaging module according to any one of claims 1 to 3.

5. 5. The imaging module according to claim 4, wherein a hole (20a) or a depression (20b) is provided in a portion of the surface of the recess facing the wavy portion.

6. an adhesive layer that adheres the imaging element chip to the recess; The surface of the recess has a wavy surface (20c) that is curved in a wavy manner, the wavy portion is adhered to the wavy surface by the adhesive layer in a state where the wavy portion is curved in a wavy shape along the wavy surface; The imaging module according to any one of claims 1 to 3.

7. 4. The imaging module according to claim 1, wherein an electrode pad (36) is provided on a surface of the outer peripheral region of the imaging element chip in a region other than the corrugated portion.

Images