Image sensor packaging structure and packaging method

Abstract

The present application discloses an image sensor packaging structure and a packaging method. The outer side of the transparent cover is narrow at the top and wide at the bottom, and space is reserved for dispensing glue from one side of the outer side of the transparent cover, so that the filling glue can first flow from one side of the transparent cover into the first bottom surface of the substrate outside the sensing chip, and the liquid level of the filling glue rises from the bottom to the top, and can fully cover the leads. It is particularly suitable for image sensor structures where the leads are relatively dense and it is not convenient to eject atomized filling glue from both sides below the leads.

Description

Technical Field

[0001] The present application relates to the field of semiconductor chip packaging technology, and in particular to an image sensor packaging structure and packaging method. Background Art

[0002] Image sensors are the core devices of digital imaging equipment, which can convert optical image signals into electronic signals for processing. In order to protect the chip of the image sensor, make it work stably and maintain good sensing sensitivity for a long time, it is usually necessary to design a stable and reliable packaging structure. When packaging the image sensor, on the one hand, the photosensitive area of ​​the sensing chip must be protected; on the other hand, the electrical connection lines between the sensor and the external circuit must be protected to prevent external factors from affecting the normal acquisition and processing of the sensing signal.

[0003] The applicant disclosed an image sensor packaging structure and packaging method in a patent application with publication number CN110021619A, in which filling glue is directly injected vertically above the lead, providing a relatively stable and reliable packaging structure. The possible minor defects are: after the filling glue is injected vertically above the lead, the filling glue is diverted after contacting the lead, and the filling glue cannot completely wrap around the lead at the part of the lead facing away from the injection direction, which may cause the lead to break in a bumpy environment.

[0004] In order to solve the problem of possible lead breakage, the applicant disclosed an image sensor packaging method in a patent application with publication number CN116936594A, which solves the problem of easy lead breakage by "using a nozzle to eject atomized filling glue from both sides of the lead at high frequency onto the lead, spraying the lead surface until the outside of the lead is completely covered with the filling glue; then, when the filling glue on the lead surface has not yet solidified, fill the filling glue into the filling chamber with liquid until the liquid level of the filling glue is higher than the highest height of all the leads". However, when the sensing chip needs to be electrically connected to the substrate through leads on all sides, the leads are densely distributed, especially the leads at the corners, which increases the difficulty of the nozzle ejecting atomized filling glue from both sides below the leads.

[0005] The image sensor obtained by the image sensor packaging method disclosed in the patent application with publication number CN116936594A can meet the AEC-Q series certification promoted by the North American automotive industry; in order to make the performance of the image sensor even better, the applicant continues to study on solving the problem of lead firmness of automotive-grade image sensors, hoping to obtain better options. Summary of the invention

[0006] In view of this, the present application provides an image sensor packaging method on one hand, wherein the outer surface of the longitudinal section of the transparent cover is narrow at the top and wide at the bottom, and space is reserved for dispensing glue from one side of the transparent cover, so that the filling glue can first flow from one side of the transparent cover into the first bottom surface of the substrate outside the sensing chip, and the liquid level of the filling glue rises from the bottom to the top, which can fully cover the lead wire, thereby solving the problem that the lead wire is easy to break;

[0007] The specific technical solutions are as follows:

[0008] The image sensor packaging method is characterized by comprising the following steps:

[0009] S1. providing a substrate, wherein the substrate has a first bottom surface and a second bottom surface opposite to the first bottom surface;

[0010] S2, mounting the sensing chip on the substrate, wherein the second surface of the sensing chip is mounted on the first bottom surface of the substrate; the first surface of the sensing chip has a sensing area, and the first surface of the sensing chip is opposite to the second surface;

[0011] S3, installing a transparent cover plate, wherein the transparent cover plate includes an integrally formed light-transmitting area and a supporting portion, and the outer surface of the transparent cover plate is narrow at the top and wide at the bottom, so as to reserve space for dispensing glue from one side of the transparent cover plate;

[0012] The outer side surface of the transparent cover plate has a transparent cover plate curved surface extending downward and outward, and the transparent cover plate curved surface extends downward and outward to the first surface of the sensing chip;

[0013] Or the outer side surface of the transparent cover plate has a transparent cover plate inclined slope extending downward and outward, and the transparent cover plate inclined slope extends downward and outward to the first surface of the sensing chip;

[0014] Installing the supporting portion of the transparent cover plate above the area outside the sensing area of ​​the sensing chip, wherein the light-transmitting area is located above the sensing area;

[0015] S4, electrically connecting the sensing chip to the substrate by electrically connecting the terminal pads of the substrate and the bonding pads of the sensing chip through a plurality of leads;

[0016] S5. Dispensing glue to form a filling glue layer is performed by dispensing glue from the outer side surface of the transparent cover plate. The filling glue first flows from one side of the outer side surface of the transparent cover plate to the first bottom surface of the substrate outside the sensing chip. The liquid level of the filling glue rises from bottom to top, fully covering the first bottom surface outside the sensing chip, the outer side surface of the sensing chip, the first surface of the sensing chip outside the transparent cover plate, the leads, and the outer side surface of the transparent cover plate.

[0017] In some embodiments, in step S3, the transparent cover is fixed above the outer area of ​​the sensing region of the sensing chip through the filling glue layer.

[0018] In some embodiments, in step S3, the bottom of the supporting portion of the transparent cover is fixed above the outer area of ​​the sensing region of the sensing chip through an adhesive layer.

[0019] In some embodiments, in step S3, the supporting portion of the transparent cover is continuous or discontinuous.

[0020] In some embodiments, in step S1, the substrate includes a side plate surrounding the substrate, and the inner side surface of the side plate has a side plate inclined slope extending downward toward the terminal pad, or the inner side surface of the side plate has a side plate curved surface extending downward toward the terminal pad;

[0021] In the step S5, glue is dispensed to form a filling glue layer, which is done by dispensing glue from the outer side surface of the transparent cover plate and the inner side surface of the side plate. The filling glue first flows from the outer side surface of the transparent cover plate and the inner side surface of the side plate to the first bottom surface of the substrate outside the sensing chip, and the liquid level of the filling glue rises from bottom to top, fully covering the first bottom surface outside the sensing chip, the outer side surface of the sensing chip, the first surface of the sensing chip outside the transparent cover plate, the leads, and the outer side surface of the transparent cover plate and the inner side surface of the side plate.

[0022] A second aspect of the present application also provides an image sensor packaging structure obtained according to the image sensor packaging method described in the present application.

[0023] The existing technology adopts: using two nozzles to high-frequency eject atomized filling glue onto the lead from both sides below the lead, spraying the surface of the lead until the outside of the lead is completely covered with the filling glue, and then filling the liquid filling glue toward the filling chamber when the filling glue on the surface of the lead has not yet solidified; however, when the sensing chip needs to be electrically connected to the substrate through leads on all sides, the leads are densely distributed, especially the leads at the corners, which increases the difficulty of the nozzle ejecting the atomized filling glue from both sides below the lead.

[0024] Beneficial effects of this application:

[0025] 1) In the image sensor packaging structure described in the present application, the outer side of the transparent cover is narrow at the top and wide at the bottom, so that space is reserved for dispensing glue from the outer side of the transparent cover, so that the filling glue can first flow from the outer side of the transparent cover into the first bottom surface of the substrate outside the sensing chip, and the liquid level of the filling glue rises from the bottom to the top, which can fully cover the lead; abandoning the prior art of directly injecting the filling glue vertically above the lead; the present application adopts: avoiding the lead, dispensing glue from the outer side of the transparent cover, and the liquid level of the filling glue rises from the bottom to the top, which fully covers the lead.

[0026] 2) The present application also provides an idea of ​​dispensing glue from one side of the side panel of the substrate, wherein the inner side surface of the side panel has an inclined slope or a curved side panel surface extending downward toward the terminal pad, thereby reserving space for dispensing glue from the inner side surface of the side panel; or reserving space for dispensing glue from both the transparent cover plate and the inner side surface of the side panel; the distance between the side panel and the terminal pad can be controlled, and the space for dispensing glue from one side of the side panel can be controlled, thereby reserving sufficient space for convenient dispensing glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The image sensor packaging method disclosed in the patent application with publication number CN110021619A;

[0028] Figure 2 The image sensor packaging method disclosed in the patent application with publication number CN116936594A;

[0029] Figure 3 It is a schematic diagram of an image sensor with densely distributed leads;

[0030] Figure 4 This is the first image sensor packaging structure of the present application;

[0031] Figure 5 This is the second image sensor packaging structure of the present application;

[0032] Figure 6 This is the third image sensor packaging structure of the present application;

[0033] Figure 7 This is the fourth image sensor packaging structure of the present application;

[0034] Figure 8 This is a method of the fifth image sensor packaging structure of the present application;

[0035] Fig. 9 This is another embodiment of the fifth image sensor packaging structure of the present application;

[0036] In the figure:

[0037] 10: substrate, 11: first bottom surface, 12: second bottom surface, 13: side plate, 14: inner side surface of the side plate, 141: inclined slope of the side plate, 15: terminal pad;

[0038] 20. sensing chip, 21. first surface, 22. second surface, 23. sensing area, 24. bonding pad, 25. outer side of the sensing chip;

[0039] 30. Transparent cover plate, 31. Light-transmitting area, 32. Inclined slope of transparent cover plate, 321. Curved surface of transparent cover plate, 33. Supporting part, 34. Receptacle; 35. Outer side surface of transparent cover plate;

[0040] 40. Lead wire; 50. Nozzle; 60. Filling glue layer. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described in the present application are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0042] This application abandons the existing Figure 1 The method shown is to inject the filling glue from the vertical top of the lead.

[0043] This application also abandons the existing Figure 2 As shown, two nozzles 50 are used to inject atomized filling glue onto the lead at high frequency from both sides below the lead to spray the surface of the lead, so as to achieve the technology of completely wrapping the lead with the filling glue.

[0044] like Figure 3 When the sensing chip needs to be electrically connected to the substrate through leads on all sides, the leads are densely distributed, especially the leads at the corners, which increases the difficulty of the nozzle to eject the atomized filling glue from both sides below the leads.

[0045] The present application optimizes the transparent cover plate. The outer side of the optimized transparent cover plate is narrow at the top and wide at the bottom, so that space is reserved for dispensing glue from one side of the outer side of the transparent cover plate, so that the filling glue can first flow from one side of the outer side of the transparent cover plate into the first bottom surface 11 of the substrate outside the sensing chip 20, and the liquid level of the filling glue rises from the bottom to the top, and can fully cover the lead 40.

[0046] Example 1

[0047] like Figure 4 , an image sensor packaging structure, comprising:

[0048] A substrate 10, the substrate having a first bottom surface 11 and a second bottom surface 12 opposite to the first bottom surface;

[0049] A sensing chip 20, wherein the sensing chip has a first surface 21 and a second surface 22 opposite to the first surface. The sensing chip 20 is disposed on the first bottom surface 11, and the first surface 21 of the sensing chip has a sensing area 23;

[0050] A transparent cover plate 30, wherein the transparent cover plate includes a light-transmitting area 31, and the light-transmitting area 31 is located above the sensing area 23;

[0051] A plurality of leads 40 electrically connecting the terminal pads 15 of the substrate and the bonding pads 24 of the sensing chip;

[0052] The transparent cover plate further includes a support portion 33; the light-transmitting area 31 and the support portion 33 are integrally formed; the support portion 33 and the light-transmitting area 31 form a cavity 34, and the sensing area 23 is located in the cavity 34; the support portion 33 is disposed above the outer area of ​​the sensing area 23 of the sensing chip;

[0053] A filling glue layer 60 is formed by dispensing glue, and the filling glue layer 60 covers the lead 40, the outer side surface 35 of the transparent cover plate, the first surface 21 of the sensing chip outside the transparent cover plate, the outer side surface 25 of the sensing chip, and the upper part of the first bottom surface 11 outside the sensing chip;

[0054] The outer side surface 35 of the transparent cover plate is narrow at the top and wide at the bottom, so as to reserve space for dispensing glue from one side of the outer side surface 35 of the transparent cover plate; Figure 4 The outer side profile of the longitudinal section of the transparent cover is narrow at the top and wide at the bottom. The “narrow at the top” allows for a larger glue dispensing space at the top; the “wide at the bottom” allows the filling glue to move downward along the outer side of the transparent cover and flow into the first bottom surface 11 of the substrate outside the sensing chip. The outer side of the transparent cover plays a guiding role.

[0055] like Figure 4 Specifically, the outer side surface of the transparent cover has a transparent cover inclined slope 32 extending downward and outward, and the "extending outward" can be understood as: the transparent cover is located in the area between the sensing area 23 and the bonding pad 24, and the lower end of the transparent cover inclined slope 32 extends toward the bonding pad 24 side compared to the sensing area 23 side of the sensing chip.

[0056] like Figure 4 The “inclined slope of the transparent cover plate” can be understood as: when viewed from the longitudinal section of the transparent cover plate, the outer contour of the transparent cover plate is a straight slope.

[0057] The inclined slope of the transparent cover helps the filling glue dispensed from one side of the transparent cover to flow smoothly into the first bottom surface of the substrate outside the sensing chip without being affected by the obstruction of the middle part of the lead, which is the middle part of the lead, that is, the part away from the terminal pad 15 and away from the bonding weld 24.

[0058] The transparent cover plate may be fixed in such a manner that the bottom of the support portion 33 of the transparent cover plate is fixed above the outer area of ​​the sensing region of the sensing chip through an adhesive layer.

[0059] The fixing method of the transparent cover plate may also be: the bottom of the support portion 33 of the transparent cover plate is not fixed above the outer area of ​​the sensing area of ​​the sensing chip through the adhesive layer, but the outer side surface of the transparent cover plate is fixed by the filling glue layer 60, so that the transparent cover plate 30, the sensing chip 20 and the substrate 10 are fixed.

[0060] The support portion 33 of the transparent cover plate can be continuous or discontinuous. When the support portion 33 is continuous, it can surround the sensing area 23 to form protection and prevent the filling glue layer from contaminating the sensing area;

[0061] When the support portion 33 is discontinuous, the air pressure in the cavity 34 formed by the lower surface of the light-transmitting area, the inner surface of the support portion and the top surface of the sensing chip can be released to avoid expansion due to high temperature in subsequent processes.

[0062] Example 2

[0063] like Figure 5 The outer side surface 35 of the transparent cover plate can also be a transparent cover plate curved surface 321 extending downward and outward. The "extending outward" can be understood as: the transparent cover plate is located in the area between the sensing area and the bonding pad, and the lower end of the transparent cover plate curved surface extends toward the bonding pad side compared to the sensing area side of the sensing chip.

[0064] Example 3

[0065] like Figures 6 to 9 The substrate further includes a side plate 13 surrounding the substrate, and the filling adhesive layer 60 is located on the inner side surface 14 of the side plate.

[0066] like Figure 6 The inner side surface of the side plate has a side plate inclined slope 141 extending downward toward the terminal pad, which reserves space for dispensing glue from one side of the inner side surface of the side plate.

[0067] like Figure 7 and Figure 8The inner side surface 14 of the side panel has a side panel inclined slope 141 extending downward toward the terminal pad 15. When the outer side surface of the transparent cover is a transparent cover inclined slope or a transparent cover curved surface extending downward and outward, the side panel inclined slope 141 of the inner side panel is a space reserved for glue dispensing from the inner side surface of the side panel; or a space reserved for glue dispensing from both the outer side surface of the transparent cover and the inner side surface 14 of the side panel.

[0068] When dispensing glue from the inner side surface 14 of the side panel, the height of the side panel is slightly higher than the height of the transparent cover panel; considering that the filling glue has a certain viscosity, when dispensing glue from the inner side surface of the side panel, the filling glue layer will form a slope slightly inclined downward from the side panel to the transparent cover panel; in addition, the side panel is higher than the transparent cover panel, which, to a certain extent, provides a certain protection for the transparent cover panel.

[0069] like Figure 8 and Fig. 9 The position of the side panel 14 on the substrate can be controlled, and the distance between the side panel and the terminal pad can be controlled, that is, the space for glue dispensing from one side of the side panel can be controlled, and sufficient space for convenient glue dispensing can be reserved.

[0070] The present application provides a method of dispensing glue from the outer side surface 32 of the transparent cover plate, or dispensing glue from the inner side surface 14 of the side plate, or dispensing glue from both the transparent cover plate and the side plate, which is particularly suitable for image sensor structures with dense leads that are not convenient for ejecting atomized filling glue from both sides below the leads.

Claims

1. An image sensor packaging method, characterized in that: The following steps are involved: S1. providing a substrate, wherein the substrate has a first bottom surface and a second bottom surface opposite to the first bottom surface; S2, mounting the sensing chip on the substrate, wherein the second surface of the sensing chip is mounted on the first bottom surface of the substrate; the first surface of the sensing chip has a sensing area, and the first surface of the sensing chip is opposite to the second surface; S3, installing a transparent cover plate, wherein the transparent cover plate includes an integrally formed light-transmitting area and a supporting portion, and the outer surface of the transparent cover plate is narrow at the top and wide at the bottom, so as to reserve space for dispensing glue from one side of the transparent cover plate; The outer side surface of the transparent cover plate has a transparent cover plate curved surface extending downward and outward, and the transparent cover plate curved surface extends downward and outward to the first surface of the sensing chip; Or the outer side surface of the transparent cover plate has a transparent cover plate inclined slope extending downward and outward, and the transparent cover plate inclined slope extends downward and outward to the first surface of the sensing chip; Installing the supporting portion of the transparent cover plate above the area outside the sensing area of ​​the sensing chip, wherein the light-transmitting area is located above the sensing area; S4, electrically connecting the sensing chip to the substrate by electrically connecting the terminal pads of the substrate and the bonding pads of the sensing chip through a plurality of leads; S5. Dispensing glue to form a filling glue layer is performed by dispensing glue from the outer side surface of the transparent cover plate. The filling glue first flows from one side of the outer side surface of the transparent cover plate to the first bottom surface of the substrate outside the sensing chip. The liquid level of the filling glue rises from bottom to top, fully covering the first bottom surface outside the sensing chip, the outer side surface of the sensing chip, the first surface of the sensing chip outside the transparent cover plate, the leads, and the outer side surface of the transparent cover plate.

2. The image sensor packaging method according to claim 1, characterized in that: In step S3, the transparent cover is fixed above the outer area of ​​the sensing area of ​​the sensing chip through the filling glue layer.

3. The image sensor packaging method according to claim 1, characterized in that: In step S3, the bottom of the supporting portion of the transparent cover is fixed above the outer area of ​​the sensing region of the sensing chip through an adhesive layer.

4. The image sensor packaging method according to claim 1, characterized in that: In step S3, the support portion of the transparent cover is continuous or discontinuous.

5. The image sensor packaging method according to claim 1, characterized in that: In step S1, the substrate includes a side plate surrounding the substrate, the inner side surface of the side plate has a side plate inclined slope extending downward toward the terminal pad, or the inner side surface of the side plate has a side plate curved surface extending downward toward the terminal pad; In the step S5, glue is dispensed to form a filling glue layer, which is done by dispensing glue from the outer side surface of the transparent cover plate and the inner side surface of the side plate. The filling glue first flows from the outer side surface of the transparent cover plate and the inner side surface of the side plate to the first bottom surface of the substrate outside the sensing chip, and the liquid level of the filling glue rises from bottom to top, fully covering the first bottom surface outside the sensing chip, the outer side surface of the sensing chip, the first surface of the sensing chip outside the transparent cover plate, the leads, and the outer side surface of the transparent cover plate and the inner side surface of the side plate.

6. An image sensor packaging structure obtained according to the image sensor packaging method according to any one of claims 1 to 4.

7. The image sensor packaging structure obtained by the image sensor packaging method according to claim 5.

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