Mortise and tenon packaging structure for enhancing heat dissipation performance

Abstract

The utility model provides a mortise and tenon packaging structure capable of enhancing heat dissipation performance. The mortise and tenon packaging structure comprises a substrate, a chip, a thermal interface material and a heat dissipation cover, the chip is welded and packaged with the substrate through a welding ball on the substrate, the lower surface of the heat dissipation cover is connected with the chip through the thermal interface material, and the edge position of the heat dissipation cover is connected with the substrate through an adhesive; a tenon is formed on the first surface of the thermal interface material, and a mortise groove matched with the tenon is formed in the second surface of the heat dissipation cover; or, a mortise groove is formed in the first surface of the thermal interface material, and a tenon is formed on the second surface of the heat dissipation cover; the mortise groove and the tenon are embedded with each other, so that the contact area of the thermal interface material and the heat dissipation cover is increased, warping of the heat dissipation cover is inhibited, layering of the heat dissipation cover and the thermal interface material is reduced, and the reliability of the device is improved.

Description

Technical Field

[0001] This utility model relates to the field of chip packaging technology, and in particular to a mortise and tenon packaging structure that enhances heat dissipation performance. Background Technology

[0002] In FCBGA devices, thermal interface materials are used to connect the chip and the heatsink, fill the gaps between the interfaces to improve heat dissipation efficiency, and absorb the stress caused by the mismatch in their coefficients of thermal expansion. The packaging structure of the thermal interface material (especially the packaging structure between the heatsink and the thermal interface material) can directly affect the overall performance in various aspects.

[0003] In existing technologies, the packaging solutions for silicone oil-based thermal interface materials typically involve directly mounting the thermal interface material onto the chip, coating a ring of adhesive (AD glue) around the thermal interface material (on the substrate), adding a heat sink, and then pressing the package together to form the encapsulation structure. Both the heat sink and the thermal interface material are flat structures, resulting in a relatively small contact area and low heat dissipation efficiency. Furthermore, given the low adhesive strength (<70 kPa), the mismatch in thermal expansion coefficients between the chip and the heat sink during device operation can easily generate internal stress. This stress can cause delamination between the heat sink and the thermal interface material, further reducing the contact area and heat dissipation efficiency, thus requiring further improvement. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of the aforementioned background technology by providing a solution that increases the contact area between the thermal interface material and the heat sink, makes it less prone to delamination during device service, and ensures reliable heat dissipation.

[0005] To achieve the above objectives, this utility model provides a mortise and tenon encapsulation structure for enhanced heat dissipation performance, including a substrate, a chip, a thermal interface material, and a heat dissipation cover; the chip is soldered to the substrate via solder balls on the substrate, the lower surface of the heat dissipation cover is connected to the chip via the thermal interface material, and the edge of the heat dissipation cover is connected to the substrate via adhesive.

[0006] The first surface of the thermal interface material has a tenon, and the second surface of the heat dissipation cover has a mortise that matches the tenon; or, the first surface of the thermal interface material has a mortise, and the second surface of the heat dissipation cover has a tenon; the mortise and the tenon fit together to increase the contact area between the thermal interface material and the heat dissipation cover and suppress the warping of the heat dissipation cover.

[0007] Furthermore, the tenons and mortises are evenly distributed in multiples on the first surface of the thermal interface material or the second surface of the heat dissipation cover.

[0008] Furthermore, the tenon and the mortise are elongated, cross-shaped, or I-shaped.

[0009] Furthermore, the second surface of the heat dissipation cover is provided with a covering groove, the covering groove being matched with the overall size of the thermal interface material, and the tenon or mortise of the heat dissipation cover being provided on the bottom surface of the covering groove.

[0010] The above-mentioned solution of this utility model has the following beneficial effects:

[0011] The mortise and tenon encapsulation structure for enhanced heat dissipation provided by this utility model can significantly increase the contact area between the heat dissipation cover and the heat interface material by interlocking the mortise or tenon of the heat dissipation cover with the tenon or mortise of the heat interface material. Furthermore, during service, the mortise and tenon interlocking between the heat dissipation cover and the heat interface material can provide stress in the opposite direction (locking the heat dissipation cover) to a certain extent to reduce warping, thereby effectively suppressing the warping of the heat dissipation cover, reducing the delamination between the heat dissipation cover and the heat interface material, and further improving the reliability of the device.

[0012] Other beneficial effects of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the mortise and tenon joint between the heat dissipation cover and the thermal interface material of this utility model.

[0015] Figure 3 This is a schematic diagram of the coating groove of this utility model.

[0016] [Explanation of Labels in the Attached Image]

[0017] 1-Substrate; 2-Chip; 3-Thermal interface material; 4-Heat sink; 5-Solder ball; 6-Adhesive; 7-Tenon; 8-Mortise; 9-Covering groove. Detailed Implementation

[0018] To make the technical problems, solutions, and advantages of this utility model clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0019] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] like Figure 1 As shown, an embodiment of this utility model provides a mortise and tenon package structure for enhanced heat dissipation, including a substrate 1, a chip 2, a thermal interface material 3, and a heat sink 4. The chip 2 is soldered to the substrate 1 via multiple solder balls 5, forming an electrical connection. During device operation, the chip 2 generates heat. A heat sink 4 is positioned above the chip 2, and its lower surface is connected to the chip 2 via the thermal interface material 3. This allows the heat generated by the chip 2 to be transferred to the heat sink 4 and dissipated into the environment, thus achieving heat dissipation for the chip 2. The edges of the heat sink 4 are connected to the substrate 1 via adhesive 6 (AD adhesive).

[0022] Among them, thermal interface material 3 (TIM) is a material used to coat the heat dissipation structure and the heat-generating device to reduce the thermal resistance between them. Currently, thermally conductive gels and thermally conductive pads are commonly used. Meanwhile, such as Figure 2As shown, compared to the traditional method, in this embodiment, a tenon 7 is formed on the upper surface of the thermal interface material 3, and a mortise 8 matching the tenon 7 is formed on the lower surface of the heat sink 4. Alternatively, the upper surface of the thermal interface material 3 can have a mortise 8, and the lower surface of the heat sink 4 can have a tenon 7. When the heat sink 4 is installed in place, the mortise 8 or tenon 7 of the heat sink 4 and the tenon 7 or mortise 8 of the thermal interface material 3 fit together. This structure can significantly increase the contact area between the thermal interface material 3 and the heat sink 4. Furthermore, during service, the mortise and tenon fit between the heat sink 4 and the thermal interface material 3 can, to a certain extent, provide a reverse stress (locking the heat sink 4) to reduce warping, thereby effectively suppressing the warping of the heat sink 4, reducing delamination between the heat sink 4 and the thermal interface material 3, and further improving the reliability of the device.

[0023] As a preferred embodiment, in this embodiment, the tenon 7 and the mortise 8 are set as elongated strips on the upper surface of the thermal interface material 3 or the lower surface of the heat dissipation cover 4. This form is convenient for processing. Of course, in other embodiments, they can also be set as cross-shaped, I-shaped, etc. Those skilled in the art can determine the preferred solution based on a limited number of tests.

[0024] In a preferred embodiment, the tenons 7 and mortises 8 are evenly distributed on the upper surface of the thermal interface material 3 or the lower surface of the heat dissipation cover 4 in this embodiment, so as to further increase the contact area between the thermal interface material 3 and the heat dissipation cover 4 (increase by 50% to 70%), and at the same time better suppress the warping of the heat dissipation cover 4, so that the lower surface of the heat dissipation cover 4 remains in contact with the thermal interface material 3.

[0025] At the same time, such as Figure 3 As shown, in this embodiment, the lower surface of the heat sink cover 4 can be further provided with a covering groove 9. The covering groove 9 matches the overall size of the thermal interface material 3, and can completely cover the thermal interface material 3. The tenon 7 or mortise 8 is provided on the bottom surface of the covering groove 9. Therefore, based on the tenon and mortise fitting between the thermal interface material 3 and the heat sink cover 4, the edge of the thermal interface material 3 is also covered by the heat sink cover 4, further increasing the contact area and reducing the risk of warping of the heat sink cover 4.

[0026] The following case further demonstrates the effectiveness of this solution. In Case 1, a thermal pad is used as the thermal interface material 3, along with the FCBGA-H chip 2 and its supporting substrate 1. The heat sink 4 has a package size of 37.5*37.5mm, and the heat sink 4 is tenon-and-mortise fitted with the thermal pad. A certain type of adhesive 6 with a dosage of 200mg is used. The encapsulation process is completed after dispensing, pressing, capping, pre-curing, curing, and reflow. After a complete Precon reliability test, the encapsulation coverage reached 99.18%, and the reliability test coverage reached 97.45%. No obvious delamination was observed at the edges, and the measured interface thermal resistance was 26.08kmm.2 / W.

[0027] In contrast, Case 2 used a thermal pad as the thermal interface material 3, an FCBGA-H chip 2 and its supporting substrate 1, and a heat sink 4 with a package size of 37.5*37.5mm. The heat sink 4 and the thermal pad were not interlocked. A certain type of adhesive 6 was used with a dosage of 200mg. The encapsulation process involved dispensing, pressing, capping, pre-curing, curing, and reflow. After a complete Precon reliability test, the encapsulation coverage was 93.26%, and the reliability test coverage was 85.12%. Obvious delamination was observed at the edges, and the measured interface thermal resistance was 96.14kmm. 2 / W.

[0028] The two cases above demonstrate that the mortise and tenon joint between the heat sink 4 and the thermal interface material 3 can significantly improve the coverage, reduce the delamination caused by the warping of the heat sink 4, and significantly reduce the interface thermal resistance, thereby improving the heat dissipation performance of the chip 2 and reducing the risk of failure.

[0029] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0030] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A mortise and tenon encapsulation structure for enhanced heat dissipation, characterized in that, It includes a substrate, a chip, a thermal interface material, and a heat sink cover; the chip is soldered to the substrate via solder balls on the substrate, the lower surface of the heat sink cover is connected to the chip via the thermal interface material, and the edge of the heat sink cover is connected to the substrate via adhesive. The first surface of the thermal interface material has a tenon, and the second surface of the heat dissipation cover has a mortise that matches the tenon; or, the first surface of the thermal interface material has a mortise, and the second surface of the heat dissipation cover has a tenon; the mortise and the tenon fit together to increase the contact area between the thermal interface material and the heat dissipation cover and suppress the warping of the heat dissipation cover.

2. The mortise and tenon encapsulation structure for enhanced heat dissipation according to claim 1, characterized in that, The tenons and mortises are evenly distributed in multiples on the first surface of the thermal interface material or the second surface of the heat dissipation cover.

3. A mortise and tenon encapsulation structure for enhanced heat dissipation according to claim 1 or 2, characterized in that, The tenon and the mortise are long strip-shaped, cross-shaped, or I-shaped.

4. The mortise and tenon encapsulation structure for enhanced heat dissipation according to claim 1, characterized in that, The second surface of the heat dissipation cover is provided with a covering groove, which matches the overall size of the thermal interface material, and the tenon or mortise of the heat dissipation cover is provided on the bottom surface of the covering groove.

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