Packaging methods and packaging structures for image sensor chips

Abstract

This invention provides a packaging method and packaging structure for an image sensor chip. By setting a light-absorbing layer on the sidewalls of the support structure and the light-transmitting cover, the stray light effect caused by reflection of strong light or large-angle light on the chip edge can be effectively reduced, thereby improving the imaging quality and enhancing the overall performance of the image sensor.

Description

Technical Field

[0001] This invention relates to a packaging method and packaging structure for an image sensor chip. Background Technology

[0002] As the requirements for image quality in CMOS image sensor (CIS) chips continue to increase, the photosensitive area within the chip is becoming larger. Simultaneously, due to cost considerations, the overall chip area is being controlled more strictly, resulting in a decreasing distance between the photosensitive area and the chip edge. In practical applications, strong light or wide-angle light illuminating the chip is more likely to cause reflections at the chip edge, resulting in stray light (flare) and thus affecting image quality.

[0003] Current technologies for solving stray light problems mainly focus on improving lens coatings, but this is costly and has limited effectiveness. Summary of the Invention

[0004] The purpose of this invention is to provide a packaging method and packaging structure for an image sensor chip, which reduces the stray light effect caused by reflection of strong light or wide-angle light at the chip edge, thereby improving imaging quality and enhancing the overall performance of the image sensor.

[0005] To address the aforementioned technical problems, the present invention provides a packaging method for an image sensor chip, comprising: providing an image sensor chip having a front side and a back side, wherein a photosensitive area is formed on the front side; providing a light-transmitting cover plate having a first surface and a second surface, wherein a support structure is formed on the first surface; disposing the light-transmitting cover plate above the image sensor chip, wherein the first surface of the light-transmitting cover plate faces the front side of the image sensor chip, and the support structure is located around the photosensitive area; wherein a first light-absorbing layer is disposed on the sidewall of the support structure, and a second light-absorbing layer is disposed on the sidewall of the light-transmitting cover plate.

[0006] Preferably, the first light-absorbing layer covers the inner wall of the support structure near the photosensitive area and the outer wall away from the photosensitive area.

[0007] Preferably, the first light-absorbing layer also covers the lower surface of the support structure and part of the first surface of the light-transmitting cover.

[0008] Preferably, after the support structure is formed on the first surface of the light-transmitting cover, a first light-absorbing layer is formed on the first surface of the light-transmitting cover and the surface of the support structure, and a portion of the first light-absorbing layer corresponding to the photosensitive area is removed.

[0009] Preferably, the first surface of the light-transmitting cover is etched to form a raised platform as the support structure.

[0010] Preferably, a patterned photoresist layer is formed on the first surface of the light-transmitting cover as the support structure.

[0011] Preferably, after the light-transmitting cover is placed above the image sensor chip, a pre-cut groove is formed in the light-transmitting cover from the back side of the image sensor chip, a second light-absorbing layer is formed in the pre-cut groove, an electrical connection structure is formed on the back side of the image sensor chip, and then an independent encapsulation structure is formed by cutting from the second surface of the light-transmitting cover.

[0012] Preferably, the electrical connection structure includes a redistribution layer, a protective layer, and solder balls.

[0013] Preferably, the electrical connection structure includes a protective layer and solder balls.

[0014] Preferably, the depth of the pre-cut groove is at least 30% of the thickness of the light-transmitting cover plate.

[0015] Preferably, the first light-absorbing layer and the second light-absorbing layer are black photoresist.

[0016] Preferably, the first light-absorbing layer and the second light-absorbing layer are formed by spin coating or spray coating.

[0017] Preferably, the encapsulation method further includes: forming a third light-absorbing layer on the second surface of the light-transmitting cover, and removing a portion of the third light-absorbing layer corresponding to the photosensitive area.

[0018] Accordingly, the present invention also provides an image sensor chip packaging structure formed by the above-described packaging method, comprising: an image sensor chip having a front side and a back side, wherein a photosensitive area is formed on the front side; a light-transmitting cover having a first surface and a second surface, wherein a support structure is formed on the first surface; the light-transmitting cover is disposed above the image sensor chip, the first surface of the light-transmitting cover is opposite to the front side of the image sensor chip, and the support structure is located around the photosensitive area; wherein a first light-absorbing layer is provided on the sidewall of the support structure, and a second light-absorbing layer is provided on the sidewall of the light-transmitting cover.

[0019] The image sensor chip packaging method and packaging structure of the present invention, by providing a light-absorbing layer on the sidewall of the support structure and the light-transmitting cover, can effectively reduce the stray light effect caused by reflection of strong light or large-angle light irradiating the chip edge, thereby improving the imaging quality and improving the overall performance of the image sensor. Attached Figure Description

[0020] Figures 1-7 This is a schematic diagram illustrating the packaging method of the image sensor chip of the present invention. Detailed Implementation

[0021] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the present invention is described in detail using schematic diagrams. When describing the embodiments of the present invention in detail, the schematic diagrams are merely examples for ease of explanation and should not limit the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the packaging method and packaging structure of the image sensor chip of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] This invention provides a packaging method and packaging structure for an image sensor chip. By setting a light-absorbing layer on the sidewalls of the support structure and the light-transmitting cover, the stray light effect caused by reflection of strong light or large-angle light on the chip edge can be effectively reduced, thereby improving the imaging quality and enhancing the overall performance of the image sensor.

[0025] Figures 1-7 This is a schematic diagram illustrating the packaging method of the image sensor chip of the present invention.

[0026] See Figure 1 A light-transmitting cover 101, such as glass, is provided, having opposing first surfaces 101a and second surfaces 101b.

[0027] See Figure 2A or Figure 2B A support structure 103 is formed on the first surface 101a of the light-transmitting cover. In such a way... Figure 2A In one embodiment shown, a photoresist layer is coated on the first surface 101a of the light-transmitting cover plate. Part of the photoresist layer is removed by exposure and development to form a patterned photoresist layer 103 as the support structure; in such... Figure 2B In another embodiment shown, a photoresist layer is coated on the first surface 101a of the light-transmitting cover plate. Part of the photoresist layer is removed by exposure and development. A patterned photoresist layer is used as a mask to etch the first surface 101a of the light-transmitting cover plate, forming a raised platform 103 as the support structure. Furthermore, those skilled in the art can, as needed, use a patterned hard mask layer as the support structure, or use a patterned hard mask layer to etch the first surface of the light-transmitting cover plate to form a raised platform as the support structure.

[0028] See Figure 3 , continue with Figure 2ATaking the patterned photoresist layer 103 as a support structure as an example, after the support structure 103 is formed on the first surface 101a of the light-transmitting cover plate, a first light-absorbing layer 104 is formed on the first surface 101a of the light-transmitting cover plate and the surface of the support structure 103. For example, a black photoresist layer is formed as the first light-absorbing layer 104 by spraying or spin coating.

[0029] See Figure 4 , Figure 5 The first light-absorbing layer 104 is removed by exposure and development. Specifically, the first light-absorbing layer that will subsequently correspond to the photosensitive area 106 of the image sensor chip 105 is removed.

[0030] An image sensor chip 105 is provided, having a front side 105a and a back side 105b, wherein a photosensitive area 106 and a pad 107 are formed on the front side 105a of the image sensor chip.

[0031] The light-transmitting cover plate 101 is disposed above the image sensor chip 105, with the first surface 101a of the light-transmitting cover plate facing the front surface 105a of the image sensor chip. The support structure 103 is located around the photosensitive area 106, forming a shape as shown in the image sensor chip 105. Figure 5 The structure shown.

[0032] The support structure 103 has a first light-absorbing layer 104 on its sidewall. Preferably, the first light-absorbing layer 104 covers the inner sidewall of the support structure 103 near the photosensitive area 106 and the outer sidewall away from the photosensitive area 106. The first light-absorbing layer 104 also covers the lower surface of the support structure 103 and part of the first surface 101a of the light-transmitting cover. Therefore, by completely surrounding the support structure 103 with the first light-absorbing layer 104, strong light or wide-angle light illuminating the vicinity of the support structure 103 can be effectively absorbed by the first light-absorbing layer 104, thereby reducing the influence of stray light.

[0033] See Figure 5 , Figure 6Subsequently, a pre-cut groove 108 is formed in the image sensor chip 105 and the light-transmitting cover plate 101 along the dicing path (dashed line in the figure) between adjacent image sensor chips. The cutter forming the pre-cut groove 108 is wider than a typical cutter (<50 micrometers), preferably 70 micrometers or more, so that the pre-cut groove 108 has sufficient width (>70 micrometers) to allow black photoresist to penetrate deep into the pre-cut groove 108 by spraying or spin coating, forming a second light-absorbing layer 109 in the pre-cut groove 108. Preferably, the depth of the pre-cut groove 108 is at least 30% of the thickness of the light-transmitting cover plate 101, so that the second light-absorbing layer 109 formed on the sidewall of the light-transmitting cover plate 101 can effectively absorb strong light or large-angle light irradiating near the sidewall of the light-transmitting cover plate 101, further reducing the influence of stray light.

[0034] The pre-cutting and forming of the second light-absorbing layer generally occurs before the forming of the solder resist protective layer. Specifically, it can occur before or after the forming of the redistribution layer. In this embodiment, it is taken as occurring before the forming of the redistribution layer. After forming the second light-absorbing layer 109, an electrical connection structure including a redistribution layer 110, a protective layer 111, and solder balls 112 is formed on the back surface 105b of the image sensor chip. Finally, the pre-cutting and forming of the second light-absorbing layer 110 is achieved by cutting from the second surface 101b of the light-transmitting cover. Figure 7 The independent package structures 100A and 100B are shown. In other embodiments not shown, the redistribution layer 110 may be formed first, followed by pre-cutting and forming the second light-absorbing layer 109, and then other electrical connection structures, such as the protective layer 111 and solder balls 112, may be formed on the back side 105b of the image sensor chip. Those skilled in the art can adjust the order of steps as needed, and the present invention is not limited thereto.

[0035] Furthermore, before or after forming the support structure 103 on the first surface 101a of the light-transmitting cover, a third light-absorbing layer 102 can be formed on the second surface 101b of the light-transmitting cover, and a portion of the third light-absorbing layer corresponding to the photosensitive area 106 of the subsequent image sensor chip 105 can be removed. This allows the third light-absorbing layer 102 formed on the second surface 101b of the light-transmitting cover to cooperate with the first light-absorbing layer 104 formed below the light-transmitting cover 101 and the second light-absorbing layer 109 formed on the sidewall of the light-transmitting cover 101 to further reduce the influence of stray light. For example, the shape, size, area, thickness, and horizontal spacing of the first light-absorbing layer 104, the second light-absorbing layer 109, and the third light-absorbing layer 102 with respect to the CRA (Chief Ray Angle) of the image sensor chip 105 and the lens (not shown) can be adjusted to reduce the influence of stray light and avoid the problem that the black photoresist cannot completely cover the edge of the image sensor chip due to manufacturing deviations.

[0036] like Figure 7 As shown, the present invention also provides an image sensor chip packaging structure formed by the above-described packaging method, comprising: an image sensor chip 105 having a front side 105a and a back side 105b, wherein a photosensitive area 106 is formed on the front side 105a; a light-transmitting cover plate 101 having a first surface 101a and a second surface 101b, wherein a support structure 103 is formed on the first surface 101a; the light-transmitting cover plate 101 is disposed above the image sensor chip 105, wherein the first surface 101a of the light-transmitting cover plate is opposite to the front side 105a of the image sensor chip, and the support structure 103 is located around the photosensitive area 106; wherein a first light-absorbing layer 104 is provided on the sidewall of the support structure 103, and a second light-absorbing layer 109 is provided on the sidewall of the light-transmitting cover plate 101. By providing light-absorbing layers 104 and 109 on the sidewalls of the support structure 103 and the light-transmitting cover plate 101, the stray light effect caused by reflection of strong light or large-angle light hitting the chip edge can be effectively reduced, thereby improving imaging quality and enhancing the overall performance of the image sensor.

[0037] In summary, the image sensor chip packaging method and packaging structure of the present invention, by providing a light-absorbing layer on the sidewalls of the support structure and the light-transmitting cover, can effectively reduce the stray light effect caused by reflection of strong light or large-angle light irradiating the chip edge, thereby improving imaging quality and enhancing the overall performance of the image sensor.

[0038] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A packaging method for an image sensor chip, characterized in that, include: An image sensor chip is provided, having a front and a back side, wherein a photosensitive area is formed on the front side; A light-transmitting cover is provided, having opposing first and second surfaces, wherein a support structure is formed on the first surface; The light-transmitting cover is disposed above the image sensor chip, with the first surface of the light-transmitting cover facing the front of the image sensor chip, and the support structure located around the photosensitive area; The supporting structure has a first light-absorbing layer on its sidewall, and the light-transmitting cover has a second light-absorbing layer on its sidewall.

2. The packaging method for an image sensor chip as described in claim 1, characterized in that, The first light-absorbing layer covers the inner wall of the support structure near the photosensitive area and the outer wall away from the photosensitive area.

3. The packaging method for an image sensor chip as described in claim 2, characterized in that, The first light-absorbing layer also covers the lower surface of the support structure and part of the first surface of the light-transmitting cover.

4. The packaging method for an image sensor chip as described in claim 3, characterized in that, After the support structure is formed on the first surface of the light-transmitting cover, a first light-absorbing layer is formed on the first surface of the light-transmitting cover and the surface of the support structure, and a portion of the first light-absorbing layer corresponding to the photosensitive area is removed.

5. The packaging method for an image sensor chip as described in claim 1, characterized in that, The first surface of the light-transmitting cover is etched to form a raised platform as the support structure.

6. The packaging method for an image sensor chip as described in claim 1, characterized in that, A patterned photoresist layer is formed on the first surface of the light-transmitting cover as the support structure.

7. The packaging method for an image sensor chip as described in claim 1, characterized in that, After the light-transmitting cover plate is placed above the image sensor chip, a pre-cut groove is formed in the light-transmitting cover plate from the back side of the image sensor chip. A second light-absorbing layer is formed in the pre-cut groove. An electrical connection structure is formed on the back side of the image sensor chip. Then, an independent encapsulation structure is formed by cutting from the second surface of the light-transmitting cover plate.

8. The packaging method for an image sensor chip as described in claim 7, characterized in that, The electrical connection structure includes a redistribution layer, a protective layer, and solder balls.

9. The packaging method for an image sensor chip as described in claim 7, characterized in that, The electrical connection structure includes a protective layer and solder balls.

10. The packaging method for an image sensor chip as described in claim 7, characterized in that, The depth of the pre-cut groove is at least 30% of the thickness of the light-transmitting cover plate.

11. The packaging method for an image sensor chip as described in claim 1, characterized in that, The first light-absorbing layer and the second light-absorbing layer are black photoresist.

12. The packaging method for an image sensor chip as described in claim 1, characterized in that, The first light-absorbing layer and the second light-absorbing layer are formed by spin coating or spray coating.

13. The packaging method for an image sensor chip as described in claim 1, characterized in that, Also includes: A third light-absorbing layer is formed on the second surface of the light-transmitting cover, and a portion of the third light-absorbing layer corresponding to the photosensitive area is removed.

14. A packaging structure formed using any one of the packaging methods of claims 1-13, characterized in that, include: An image sensor chip has a front and a back side, with the front side having a photosensitive area. A light-transmitting cover plate having a first surface and a second surface opposite to each other, wherein a support structure is formed on the first surface; The light-transmitting cover is disposed above the image sensor chip, with the first surface of the light-transmitting cover facing the front of the image sensor chip, and the support structure located around the photosensitive area; The supporting structure has a first light-absorbing layer on its sidewall, and the light-transmitting cover has a second light-absorbing layer on its sidewall.

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