Packaging method and packaging structure of image sensor chip
By setting a cutting channel on the wafer of the image sensor chip, the pad is arranged at least partially in the cutting channel, and using an internal support structure to connect the photosensitive area and the pad, the insufficient distance between the photosensitive area and the pad in the prior art is solved. Stray light problems improve imaging quality.
Patent Information
- Application Number
- CN202310926980.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-26
- Publication Date
- 2025-02-07
AI Technical Summary
In the existing image sensor chip package structure, the distance between the photosensitive region and the pad is insufficient, resulting in light easily reflected on the side walls of the package structure, generating stray light, and affecting the imaging quality.
By forming an image sensor chip on the wafer and setting a cutting path between adjacent chips, the pad is at least partially arranged in the cutting path to increase the distance between the photosensitive region and the pad. Then, the inner support structure is used to fix the connection between the photosensitive area and the pad, and the distance between the edge of the photosensitive area and the inner side of the inner support structure is further increased.
It effectively reduces the reflection of light on the side walls of the inner support structure, reduces the impact of stray light, and improves the imaging quality.
Smart Images
Figure CN119403253A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of chip packaging, and in particular to a packaging method and packaging structure of an image sensor chip. Background Art
[0002] With the continuous development of the integrated circuit industry, chip integration is getting higher and higher, chip size is shrinking, and chip packaging technology is also constantly updated.
[0003] For CIS (CMOS Image Sensor) chips, as users' requirements for photo quality increase, the photosensitive area of the chip gradually increases, the non-photosensitive area gradually decreases, and the distance from the edge of the photosensitive area to the edge of the chip gradually shortens, resulting in insufficient process windows for some packaging forms.
[0004] For example Figure 1 In the COM (Chip On Module) packaging structure shown, part of the side wall 111 of the mounting frame 110 is fixedly connected to the periphery of the photosensitive area 101 of the image sensor chip 100, and is located between the photosensitive area 101 and the pad 102. Since the distance a between the photosensitive area 101 and the pad 102 is limited, the closer the distance b between the inner side of the frame side wall 111 and the edge of the photosensitive area 101 is, the easier it is for light to be reflected on the frame side wall 111 to bring stray light, thereby affecting the imaging quality.
[0005] Another example Figure 2 In the BGA (Ball Grid Array) packaging structure shown, the distance a between the pad 102 and the photosensitive area 101 is small, and the distance c between the inner side of the Dam (dam retaining wall) 121 used for packaging and the edge of the photosensitive area 101 is close, which may cause stray light problems or make it impossible to complete the packaging of the structure. Summary of the invention
[0006] The object of the present invention is to provide a packaging method and packaging structure of an image sensor chip to reduce the influence of stray light and improve imaging quality.
[0007] Based on the above considerations, one aspect of the present invention provides a packaging method for an image sensor chip, comprising: forming a plurality of image sensor chips on a wafer, the image sensor chip comprising a photosensitive area and a pad, a cutting path being arranged between adjacent image sensor chips, the pad being at least partially located in the cutting path; cutting the wafer along the cutting path to form independent image sensor chips; and fixing an internal support structure for packaging between the photosensitive area and the pad of the image sensor chip, increasing the distance from the edge of the photosensitive area to the inner side of the internal support structure, and reducing the influence of stray light.
[0008] Preferably, before the step of fixing and connecting the inner support structure for packaging, the method further includes: bonding the first end of the metal wire to the pad of the image sensor chip, and suspending the second end of the metal wire above the image sensor chip.
[0009] Preferably, the first end of the metal wire is at least partially located in the cutting path.
[0010] Preferably, the distance from the edge of the photosensitive area to the inner side of the inner support structure is greater than 100 microns.
[0011] Preferably, the width of the pad in the cutting path is greater than 1 micron.
[0012] Preferably, the image sensor chip comprises a first surface and a second surface opposite to each other, the pad is located on the first surface, the first surface is not provided with a protection ring surrounding the image sensor chip, and the second surface is provided with a protection ring surrounding the image sensor chip.
[0013] Preferably, the wafer is cut by laser stealth cutting.
[0014] Another aspect of the present invention provides a packaging structure of an image sensor chip, comprising: an image sensor chip, the image sensor chip comprising a photosensitive area and a pad, the edge of the image sensor chip having a cutting path left over from cutting; an internal support structure, the internal support structure being fixedly connected between the photosensitive area and the pad of the image sensor chip; the pad being at least partially located in the cutting path to increase the distance from the edge of the photosensitive area to the inner side of the internal support structure and reduce the influence of stray light.
[0015] Preferably, the packaging structure of the image sensor chip further includes a metal wire, a first end of the metal wire is bonded to a pad of the image sensor chip, and a second end of the metal wire is suspended above the image sensor chip.
[0016] Preferably, the first end of the metal wire is at least partially located in the cutting path.
[0017] Preferably, the distance from the edge of the photosensitive area to the inner side of the inner support structure is greater than 100 microns.
[0018] Preferably, the width of the pad in the cutting path is greater than 1 micron.
[0019] Preferably, the image sensor chip comprises a first surface and a second surface opposite to each other, the pad is located on the first surface, the first surface is not provided with a protection ring surrounding the image sensor chip, and the second surface is provided with a protection ring surrounding the image sensor chip.
[0020] The packaging method and packaging structure of the image sensor chip of the present invention increase the distance between the photosensitive area of the image sensor chip and the pad by at least partially setting the pad of the image sensor chip in the cutting path, so that when the inner support structure used for packaging is fixedly connected between the photosensitive area of the image sensor chip and the pad, the distance from the edge of the photosensitive area to the inner side of the inner support structure can be increased, thereby reducing the influence of stray light caused by the reflection of light on the side wall of the inner support structure, and improving the imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.
[0022] Figure 1 A schematic diagram of a COM packaging structure of an image sensor chip in the prior art; Figure 2 A schematic diagram of a BGA packaging structure of an image sensor chip in the prior art; Figure 3 A top view of adjacent image sensor chips in a prior art packaging method; Figure 4 A cross-sectional view of adjacent image sensor chips in a prior art packaging method; Figure 5 A top view of adjacent image sensor chips in the packaging method of the present invention; Figure 6 is a cross-sectional view of adjacent image sensor chips in the packaging method of the present invention; Figure 7 It is a schematic diagram of the COM packaging structure of the image sensor chip of the present invention; Figure 8 Schematic diagram of the BGA packaging structure of the image sensor chip of the present invention.
[0023] In the drawings, the same or similar reference numerals denote the same or similar devices (modules) or steps throughout different drawings. Implementation
[0024] In order to solve the problems in the above-mentioned prior art, the present invention provides a packaging method and packaging structure for an image sensor chip, by at least partially setting the soldering pad of the image sensor chip in the cutting path, thereby increasing the distance between the photosensitive area of the image sensor chip and the soldering pad, so that when the inner support structure used for packaging is fixedly connected between the photosensitive area of the image sensor chip and the soldering pad, the distance from the edge of the photosensitive area to the inner side of the inner support structure can be increased, thereby reducing the influence of stray light caused by the reflection of light on the side wall of the inner support structure, and improving the imaging quality.
[0025] In the following specific description of the preferred embodiments, reference will be made to the attached drawings which constitute a part of the present invention. The attached drawings show by way of example specific embodiments that can implement the present invention. The illustrative embodiments are not intended to be exhaustive of all embodiments according to the present invention. It will be appreciated that other embodiments may be utilized, and structural or logical modifications may also be made without departing from the scope of the present invention. Therefore, the following specific description is not restrictive, and the scope of the present invention is limited by the appended claims.
[0026] like Figure 3 , Figure 4 As shown, the inventors of the present application have discovered that in the prior art, after a number of image sensor chips 100 are formed on a wafer 130, two adjacent image sensor chips 100 are shown here as examples, wherein the image sensor chip 100 includes a photosensitive area 101 and a soldering pad 102, wherein the soldering pad 102 is located in a non-photosensitive area 106 outside the photosensitive area 101, and a cutting path 103 is provided between adjacent image sensor chips 100, wherein the soldering pad 102 is completely located outside the cutting path 103, occupying a larger width of the non-photosensitive area 106, thereby making it difficult to reduce the distance a between the photosensitive area 101 and the soldering pad 102.
[0027] Therefore, the inventors of the present application propose a new image sensor chip packaging method, such as Figure 5 , Figure 6 As shown, the packaging method includes: forming a plurality of image sensor chips 200 on a wafer 230, wherein two adjacent image sensor chips 200 are shown as examples, wherein the image sensor chip 200 includes a photosensitive region 201 and a pad 202, and a cutting path 203 is provided between adjacent image sensor chips 200, wherein the pad 202 is at least partially located in the cutting path 203, so as to reduce the width of the occupied non-photosensitive region 206 and increase the distance a' between the photosensitive region 201 and the pad 202. Therefore, when the wafer 230 is cut along the cutting path 203 to form an independent image sensor chip 200, when the inner support structure for packaging is fixedly connected between the photosensitive region 201 and the pad 202, the distance b' from the edge of the photosensitive region to the inner side of the inner support structure can be increased, so as to reduce the influence of stray light and improve the imaging quality. Preferably, the wafer 230 can be cut by laser hidden cutting to achieve a higher cutting accuracy and avoid damage to the pad 202 as much as possible.
[0028] Specific, for example Figure 7As shown, by bonding the first end 213 of the metal wire 212 to the pad 202 of the cut image sensor chip 200, the second end 214 of the metal wire 212 is suspended above the image sensor chip 200, and then the mounting frame 210 is fixedly connected to the image sensor chip 200, and a transparent cover plate (such as glass) 216 is mounted above the mounting frame 210, a COM packaging structure is formed. The COM packaging structure can be used to be directly mounted on a circuit board (not shown) and is electrically connected to the circuit board through the suspended second end 214 of the metal wire. The side wall 211 of the mounting frame 210 is used as an internal supporting structure, which is fixedly connected (for example, bonded) to the periphery of the photosensitive area 201 of the image sensor chip 200 and is located between the photosensitive area 201 and the pad 202. By at least partially setting the pad 202 in the cutting path 203, the distance a' between the photosensitive area 201 and the pad 202 is increased. Therefore, the distance b' between the inner side of the frame side wall 211 and the edge of the photosensitive area 201 can be increased accordingly, thereby reducing the stray light caused by the reflection of light on the frame side wall 211, thereby reducing the influence of the stray light and improving the imaging quality.
[0029] Preferably, the first end 213 of the metal wire 212 may be at least partially disposed in the cutting path 203 , so that the pad 202 may be as far away from the photosensitive region 201 as possible, thereby further increasing the distance a′ between the photosensitive region 201 and the pad 202 .
[0030] Another example Figure 8 As shown, the second side 200B of the cut image sensor chip 200 is fixed on the circuit board 227, and the opposite first side (photosensitive surface) 200A has a transparent cover (such as glass) 226 mounted above the photosensitive area 201 through a cofferdam retaining wall 221, and the pad 202 is connected to the pad 228 of the circuit board 227 through a metal wire 222, and is connected to the outside through a spherical contact array 229 on the back of the circuit board 227, forming a BGA packaging structure. The cofferdam retaining wall 221 serves as an internal supporting structure, which is fixedly connected (for example, bonded) to the periphery of the photosensitive area 201 of the image sensor chip 200 and is located between the photosensitive area 201 and the pad 202. By at least partially setting the pad 202 in the cutting path 203, the distance a' between the photosensitive area 201 and the pad 202 is increased. Therefore, the distance b' between the inner side of the cofferdam retaining wall 221 and the edge of the photosensitive area 201 can be increased accordingly, thereby reducing the stray light caused by the reflection of light on the frame side wall 211, thereby reducing the influence of the stray light and improving the imaging quality.
[0031] Preferably, the width c' of the pad 202 in the cutting path 203 is greater than 1 micron, so that the distance b' from the edge of the photosensitive area 201 to the inner side of the inner support structures 211 and 221 is greater than 100 microns, thereby ensuring a better effect of reducing stray light.
[0032] In addition, if Figure 3 , Figure 4 As shown, in the prior art, protective rings 104 and 105 surrounding the image sensor chip 100 are usually provided on the first surface 100A and the second surface 100B opposite to each other of the image sensor chip 100, and the pad 101 is located on the inner side of the protective rings 104 and 105. The problem is that if the distance from the photosensitive area 101 to the edge of the chip 100 is to be increased, or the distance a between the photosensitive area 101 and the pad 102 is to be increased, the area of the chip itself can only be increased. In this case, the number of gross dies produced per wafer will be reduced accordingly, increasing the cost of the chip. In the present invention, since the pad 202 is at least partially disposed in the cutting path 203, a protective ring surrounding the image sensor chip 200 is not provided on the first surface 200A where the pad 202 is located, and a protective ring 205 surrounding the image sensor chip 200 is only provided on the opposite second surface 200B, so as to provide sufficient space for the pad 202 to be at least partially disposed in the cutting path 203. Figure 5 , Figure 6 In the illustrated embodiment, the guard ring 205 is located directly below the pad 202 ; in other embodiments not shown, the guard ring 205 may even be located below the inner side of the pad 202 .
[0033] The present invention also provides a packaging structure of an image sensor chip, comprising: an image sensor chip 200, wherein the image sensor chip 200 comprises a photosensitive area 201 and a pad 202, wherein the edge of the image sensor chip 200 has a cutting path 203 of cutting residue; internal support structures 211, 221, wherein the internal support structures 211, 221 are fixedly connected between the photosensitive area 201 and the pad 202 of the image sensor chip 200; and the pad 202 is at least partially located in the cutting path 203 to increase the distance b' from the edge of the photosensitive area 201 to the inner side of the internal support structures 211, 221, thereby reducing the influence of stray light.
[0034] Preferably, the width c' of the pad 202 in the cutting path 203 is greater than 1 micron, so that the distance b' from the edge of the photosensitive area 201 to the inner side of the inner support structures 211 and 221 is greater than 100 microns, thereby ensuring a better effect of reducing stray light.
[0035] Preferably, the present invention is applicable to a COM package structure, the COM package structure further comprising a metal wire 212, a first end 213 of the metal wire 212 being bonded to the pad 202 of the image sensor chip 200, and a second end 214 of the metal wire 212 being suspended above the image sensor chip 200. Preferably, the first end 213 of the metal wire 212 is at least partially disposed in the cutting path 203, so that the pad 202 can be as far away from the photosensitive region 201 as possible, thereby further increasing the distance a' between the photosensitive region 201 and the pad 202.
[0036] Preferably, the image sensor chip 200 includes a first surface 200A and a second surface 200B opposite to each other, the pad 202 is located on the first surface 200A, the first surface 200A is not provided with a protection ring surrounding the image sensor chip 200, and the second surface 200B is provided with a protection ring 205 surrounding the image sensor chip 200 to reduce damage to the chip during the cutting process.
[0037] The packaging method and packaging structure of the image sensor chip of the present invention increase the distance between the photosensitive area of the image sensor chip and the pad by at least partially setting the pad of the image sensor chip in the cutting path, so that when the inner support structure used for packaging is fixedly connected between the photosensitive area of the image sensor chip and the pad, the distance from the edge of the photosensitive area to the inner side of the inner support structure can be increased, thereby reducing the influence of stray light caused by the reflection of light on the side wall of the inner support structure, and improving the imaging quality.
[0038] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, in any case, the embodiments should be considered exemplary and non-restrictive. Furthermore, it is apparent that the term "comprising" does not exclude other elements and steps, and the wording "a" does not exclude the plural. Multiple elements stated in a device claim may also be implemented by one element. The words first, second, etc. are used to indicate names and do not indicate any particular order.
Claims
1. A packaging method for an image sensor chip, characterized in that: include: Forming a plurality of image sensor chips on a wafer, wherein the image sensor chips include a photosensitive area and a pad, a dicing path is provided between adjacent image sensor chips, and the pad is at least partially located in the dicing path; Cutting the wafer along the cutting paths to form independent image sensor chips; The inner support structure used for packaging is fixedly connected between the photosensitive area and the pad of the image sensor chip, increasing the distance from the edge of the photosensitive area to the inner side of the inner support structure and reducing the influence of stray light.
2. The method for packaging an image sensor chip according to claim 1, wherein: Before the step of fixing and connecting the inner support structure for packaging, the method further includes: bonding the first end of the metal wire to the pad of the image sensor chip, and suspending the second end of the metal wire on the image sensor chip.
3. The method for packaging an image sensor chip according to claim 2, wherein: The first end of the metal wire is at least partially located in the scribe line.
4. The method for packaging an image sensor chip according to claim 1, wherein: The distance from the edge of the photosensitive area to the inner side of the inner support structure is greater than 100 microns.
5. The method for packaging an image sensor chip according to claim 4, wherein: The width of the pad in the dicing street is greater than 1 micron.
6. The method for packaging an image sensor chip according to claim 1, wherein: The image sensor chip comprises a first surface and a second surface opposite to each other, the pad is located on the first surface, the first surface is not provided with a protection ring surrounding the image sensor chip, and the second surface is provided with a protection ring surrounding the image sensor chip.
7. The method for packaging an image sensor chip according to claim 1, wherein: The wafer is cut by laser stealth cutting.
8. A packaging structure of an image sensor chip, characterized in that: include: An image sensor chip, the image sensor chip comprising a photosensitive area and a pad, and the edge of the image sensor chip having a cutting path left over from cutting; An internal support structure, wherein the internal support structure is fixedly connected between the photosensitive area and the pad of the image sensor chip; The pad is at least partially located in the cutting path to increase the distance from the edge of the photosensitive area to the inner side of the inner support structure and reduce the influence of stray light.
9. The packaging structure of the image sensor chip according to claim 8, characterized in that: It also includes a metal wire, a first end of which is bonded to a pad of the image sensor chip, and a second end of which is suspended above the image sensor chip.
10. The packaging structure of the image sensor chip according to claim 9, characterized in that: The first end of the metal wire is at least partially located in the scribe line.
11. The packaging structure of the image sensor chip according to claim 8, characterized in that: The distance from the edge of the photosensitive area to the inner side of the inner support structure is greater than 100 microns.
12. The packaging structure of the image sensor chip according to claim 11, characterized in that: The width of the pad in the scribe line is greater than 1 micron.
13. The packaging structure of the image sensor chip according to claim 8, characterized in that: The image sensor chip comprises a first surface and a second surface opposite to each other, the pad is located on the first surface, the first surface is not provided with a protection ring surrounding the image sensor chip, and the second surface is provided with a protection ring surrounding the image sensor chip.