Packaging structure for image sensor

Abstract

The invention, which relates to the semiconductor manufacturing field, discloses a packaging structure for an image sensor comprising a substrate, an image sensor, a supporting dam, a transparent cover plate, a sealing colloid and a side wall. The image sensor is attached to the upper surface of the substrate; the supporting dam is arranged around the periphery of a sensing area of the image sensor; the transparent cover plate is arranged above the sensing area and is in fit connection with the supporting dam; the side wall surrounds the peripheral edge of the upper surface of the base plate; the position height of the upper surface of the side wall is lower than that of the upper surface of the transparent cover plate; and the sealing colloid is coated in an area between the upper surface of the substrate and the outer side surface of the supporting dam. According to the packaging structure for the image sensor provided by the invention, the height of the side wall is reduced, so that a deformation abdicating space can be provided for the thermally-expanded sealing colloid, and the deformation of the light-transmitting cover caused by the extrusion of the sealing colloid is avoided.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular, to a packaging structure for an image sensor. Background Art

[0002] An image sensor is a semiconductor device that converts optical signals into electrical signals and is widely used in fields such as digital cameras, smart phones, security monitoring, and automotive electronics. Its packaging structure not only plays a physical protection role but also affects optoelectronic performance, heat dissipation capacity, and reliability.

[0003] The invention patent with the Chinese patent application number 200910176132.9 discloses an image sensor packaging structure that increases the air chamber space. This patent covers the sealing colloid on the periphery of the upper surface of the substrate and the periphery of the upper surface of the light-transmitting cover to achieve the effect of preventing water vapor from invading the lens. However, only filling the sealing colloid on the substrate will result in a relatively low overall structural strength of the packaging structure, and deformation or damage may occur in some working environments with vibration. Therefore, in the prior art, a side wall flush with the upper surface of the light-transmitting cover is provided around the periphery of the upper surface of the substrate to improve the overall structural strength of the packaging structure. However, in some high-temperature environments, the sealing colloid between the light-transmitting cover and the side wall expands thermally and squeezes the light-transmitting cover, causing deformation. Summary of the Invention

[0004] In order to solve the problem of extrusion deformation caused by the side wall and the thermally expanded sealing colloid in the prior art, the present invention provides a packaging structure for an image sensor. By reducing the height of the side wall, a deformation allowance space can be provided for the thermally expanded sealing colloid, avoiding the deformation of the light-transmitting cover caused by the extrusion of the sealing colloid.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: An encapsulation structure for an image sensor provided by the present invention includes a substrate, an image sensor, a support dam, a transparent cover plate, a sealing colloid, and sidewalls; the substrate includes a first surface, which is the upper surface of the substrate, and an installation area is provided on the first surface; the image sensor includes a second surface and a third surface, the second surface is the upper surface of the image sensor, a sensing area is provided on the second surface, and the third surface is the lower surface of the image sensor; the third surface is attached to the installation area; the support dam is provided on the second surface and surrounds the sensing area; the transparent cover plate is provided above the sensing area and is attached to the support dam; a plurality of first conductive contacts are provided on the second surface outside the sensing area; a plurality of second conductive contacts are provided on the first surface outside the installation area; the plurality of first conductive contacts correspond to the plurality of second conductive contacts one by one; the first conductive contact and its corresponding second conductive contact are electrically connected by a lead; the sidewalls surround the peripheral edge of the first surface; the position height of the upper surface of the sidewalls is lower than the position height of the upper surface of the transparent cover plate; the sealing colloid covers the outer side surface of the transparent cover plate, the outer side surface of the support dam, the area of the second surface outside the support dam, the area of the first surface outside the installation area, and the upper surface of the sidewalls.

[0006] For the encapsulation structure for an image sensor provided by the present invention, preferably, the position height of the upper surface of the sidewalls is lower than the position height of the second surface.

[0007] For the encapsulation structure for an image sensor provided by the present invention, preferably, the height dimension of the sidewalls is 5 - 10 μm.

[0008] For the encapsulation structure for an image sensor provided by the present invention, preferably, the substrate is a PCB board.

[0009] For the encapsulation structure for an image sensor provided by the present invention, preferably, the upper surface of the sealing colloid is an inclined surface, which slopes downward in the direction from the transparent cover plate to the sidewalls.

[0010] For the encapsulation structure for an image sensor provided by the present invention, preferably, the lead connects the first conductive contact and its corresponding second conductive contact by wire bonding.

[0011] The above technical solution has the following advantages or beneficial effects: A packaging structure for an image sensor provided by the present invention relates to the field of semiconductor manufacturing, and includes a substrate, an image sensor, a support dam, a transparent cover plate, a sealing colloid, and side walls; the image sensor is attached to the upper surface of the substrate; the support dam is disposed around the sensing area of the image sensor; the transparent cover plate is disposed above the sensing area and is attached to the support dam; the side walls surround the peripheral edge of the upper surface of the substrate; the position height of the upper surface of the side walls is lower than the position height of the upper surface of the transparent cover plate; the sealing colloid covers the area between the upper surface of the substrate and the outer side surface of the support dam. By reducing the height of the side walls, the packaging structure for an image sensor provided by the present invention can provide a deformation space for the thermally expanded sealing colloid, and avoid deforming the light-transmitting cover due to the extrusion of the sealing colloid. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are incorporated herein and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0013] Figure 1 It is a structural diagram of a packaging structure for an image sensor provided in Embodiment 1 of the present invention; Figure 1 Including: 1. Substrate; 11. First surface; 111. Installation area; 2. Image sensor; 21. Second surface; 211. Sensing area; 22. Third surface; 3. Support dam; 4. Transparent cover plate; 5. Sealing colloid; 6. Side walls; 7. Leads. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0015] Embodiment 1: The side walls provided on the side of the substrate ring in the prior art are generally flush with the upper cover plate, and the filling glue is filled between the outer side of the cover plate and the inner side of the side walls. When the entire packaging structure is preheated, since the materials of each part are different, when heated and expanded, the expansion rates of the cover plate, the filling glue, and the side walls are all different, so the originally fitted and fixed structure will crack, resulting in damage to the packaging structure. However, if the side walls are not provided, although enough thermal expansion space will be provided for the filling glue, the structural strength of the substrate will decrease, and the filling glue cannot be fixed well either.

[0016] As Figure 1 shown: In order to improve the reliability of the packaging structure under extreme conditions such as high temperature and vibration, a packaging structure for an image sensor provided by the present invention includes a substrate 1, an image sensor 2, a support dam 3, a transparent cover plate 4, a sealing colloid 5 and a side wall 6; the substrate 1 includes a first surface 11, the first surface 11 is the upper surface of the substrate 1, and an installation area 111 is provided on the first surface 11; the image sensor 2 includes a second surface 21 and a third surface 22, the second surface 21 is the upper surface of the image sensor 2, a sensing area 211 is provided on the second surface 21, and the third surface 22 is the lower surface of the image sensor 2; the third surface 22 is adhesively disposed on the installation area 111; the support dam 3 is disposed on the second surface 21, and the support dam 3 is disposed around the periphery of the sensing area 211; the transparent cover plate 4 is disposed above the sensing area 211 and is adhesively connected to the support dam 3; a plurality of first conductive contacts are provided on the second surface 21 outside the sensing area 211; a plurality of second conductive contacts are provided on the first surface 11 outside the installation area 111; the plurality of first conductive contacts and the plurality of second conductive contacts correspond to each other one by one; the first conductive contact and its corresponding second conductive contact are electrically connected by a lead 7; the side wall 6 surrounds the peripheral edge of the first surface 11; the position height of the upper surface of the side wall 6 is lower than the position height of the upper surface of the transparent cover plate 4; the sealing colloid 5 covers the outer side surface of the transparent cover plate 4, the outer side surface of the support dam 3, the area of the second surface 21 outside the support dam 3, the area of the first surface 11 outside the installation area 111 and the upper surface of the side wall 6.

[0017] Since the position height of the upper surface of the side wall 6 is lower than the position height of the upper surface of the transparent cover plate 4, in a high-temperature environment, when the sealing colloid 5 on the outer side surface of the transparent cover plate 4 expands due to thermal expansion, the expanded volume will expand outward and will not squeeze the outer side surface of the transparent cover plate 4, thereby avoiding the transparent cover plate 4 from being squeezed and deformed. And the setting of the side wall 6 can increase the cross-sectional area size of the edge of the substrate 1, improve its bending stiffness, and can effectively resist the extrusion stress of the sealing colloid 5 during curing on the substrate 1, the support dam 3 and the transparent cover plate 4 or other external mechanical impacts. The side wall 6 can also disperse the stress concentrated on the edge of the substrate 1 (such as the shrinkage and expansion stress of the sealing colloid 5) to a larger area, avoiding cracking caused by local stress concentration.

[0018] A packaging structure for an image sensor provided by the present invention can, by providing a side wall 6 lower than the transparent cover plate 4, while avoiding the extrusion stress of the sealing colloid 5 during thermal expansion on the transparent cover plate 4, also enable the side wall 6 and the substrate 1 to jointly form a frame structure to limit the warping deformation of the edge of the substrate 1.

[0019] Since a lead wire 7 for connecting a conductive contact point is further provided outside the support dam 3, when the sealing colloid 5 generates thermal expansion stress or the encapsulation structure cracks due to vibration, the lead wire 7 will be disconnected from the conductive contact point. In order to reduce the extrusion stress on the lead wire 7, in a preferred solution of this embodiment, the height of the upper surface of the side wall 6 is lower than the height of the second surface 21. If the height of the side wall 6 is flush with the second surface 21, the stress generated during the encapsulation process (such as the curing of the sealing colloid 5 and external mechanical shock) will be directly transmitted to the edge of the second surface 21 through the side wall 6, and then act on the lead wire 7. For example, when the sealing colloid 5 shrinks during curing, the side wall 6 may concentrate the shrinkage stress on the edge of the second surface 21 due to rigid support, resulting in the lead wire 7 being pulled or the contact point being deformed. Therefore, further reducing the height of the side wall 6 so that it is lower than the height of the image sensor 2 can provide more space for the sealing colloid 5 to give way, and avoid damage caused by excessive extrusion stress on one side of the lead wire 7.

[0020] An encapsulation structure for an image sensor provided by the present invention can avoid damage caused by excessive extrusion stress on one side of the lead wire 7 by setting the height of the side wall 6 lower than the height of the upper surface of the image sensor 2.

[0021] In a preferred solution of this embodiment, the height dimension of the side wall 6 is 5 - 10 μm. In order to ensure the overall strength of the encapsulation structure and reduce the height of the side wall 6 as much as possible, the height of the side wall 6 can be limited to 5 μm.

[0022] In a preferred solution of this embodiment, the substrate 1 is a PCB board.

[0023] In a preferred solution of this embodiment, the upper surface of the sealing colloid 5 is an inclined surface, which slopes downward in the direction from the transparent cover plate 4 to the side wall 6. Setting the top of the sealing colloid 5 as a ramp structure can reduce the thickness of the sealing colloid 5 while effectively covering each component, so as to reduce the stress generated when the sealing colloid 5 thermally expands and reduce the possibility of the encapsulation structure cracking.

[0024] In a preferred solution of this embodiment, the lead wire 7 is connected to the corresponding second conductive contact point by wire bonding.

[0025] Those skilled in the art will readily think of other embodiments of this application after considering the specification and practicing the application here. This application is intended to cover any variations, uses, or adaptations of this application, which follow the general principles of this application and include the common general knowledge or conventional technical means in the technical field not claimed in this application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of this application are pointed out by the appended claims.

[0026] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A packaging structure for an image sensor, characterized in that It includes a substrate, an image sensor, a support dam, a transparent cover plate, a sealing colloid and sidewalls; The substrate includes a first surface, which is the upper surface of the substrate, and an installation area is provided on the first surface; The image sensor includes a second surface and a third surface. The second surface is the upper surface of the image sensor, a sensing area is provided on the second surface, and the third surface is the lower surface of the image sensor; The third surface is attached to the installation area; The support dam is provided on the second surface, and the support dam is arranged around the periphery of the sensing area; The transparent cover plate is provided above the sensing area and is attached to the support dam; A plurality of first conductive contacts are provided on the periphery of the sensing area on the second surface; A plurality of second conductive contacts are provided on the periphery of the installation area on the first surface; A plurality of the first conductive contacts correspond to a plurality of the second conductive contacts one by one; The first conductive contact and its corresponding second conductive contact are electrically connected by a lead wire; The sidewalls surround the peripheral edge of the first surface; The position height of the upper surface of the sidewalls is lower than the position height of the upper surface of the transparent cover plate; The sealing colloid covers the outer side surface of the transparent cover plate, the outer side surface of the support dam, the area of the second surface outside the support dam, the area of the first surface outside the installation area, and the upper surface of the sidewalls.

2. The packaging structure for an image sensor according to claim 1, wherein, The position height of the upper surface of the sidewalls is lower than the position height of the second surface; 3. The packaging structure for an image sensor according to claim 2, wherein, The height dimension of the sidewalls is 5 - 10 μm; 4. The encapsulation structure for an image sensor according to claim 1, wherein The substrate is a PCB board; 5. The encapsulation structure for an image sensor according to claim 1, characterized in that, The upper surface of the sealing colloid is an inclined surface, which slopes downward in the direction from the transparent cover plate to the sidewalls; 6. The packaging structure for an image sensor according to claim 1, characterized in that, The lead wire connects the first conductive contact and its corresponding second conductive contact by wire bonding.

Images