A packaging structure for achieving double-sided heat dissipation
Patent Information
- Application Number
- CN202611066372.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-17
- Publication Date
- 2026-10-27
AI Technical Summary
[0004]然而，现有CLIP 双面散热封装工艺回流焊易出现铜片偏移、定位精度差等缺陷，配套限位结构或夹具会增加成本、降低产能；且受结构限制无法实现全铜片键合，产品电学性能与可靠性存在瓶颈
本申请实施例提供了一种实现双面散热的封装结构，包括：引线框架、芯片、粘片材料、双面陶瓷覆铜板及塑封树脂；其中，引线框架中设置有凹坑结构，芯片与双面陶瓷覆铜板嵌入设置在凹坑结构中，芯片与双面陶瓷覆铜板通过粘片材料粘接固定，且双面陶瓷覆铜板的背面覆铜通过焊料使芯片与引线框架直接连接；双面陶瓷覆铜板的中部陶瓷基板侧壁与引线框架凹坑结构的侧壁，双面陶瓷覆铜板G极覆铜片、S极覆铜片侧壁与引线框架G极引线、S极引线打弯台阶侧壁形成相互限位结构，相互限位结构用于对双面陶瓷覆铜板进行限位；塑封树脂用于对产品进行封装，通过对塑封树脂进行研磨后露出顶部覆铜片，顶部覆铜片作为产品顶部散热片；其中，顶部覆铜片为双面陶瓷覆铜板的正面覆铜。本方案通过特定的引线框架结构设计，配合通用的DBC结构，对DBC进行限位，解决了DBC的漂移和转角问题，并与现有技术相比，材料成本和封装成本更低；并且，通过芯片、DBC嵌入至引线框架的凹坑结构，可以提供更小的封装厚度，缩减了封装体积、提高功率密度；另外，通过DBC背面覆铜结构，替代铜线，实现全铜片键合的封装结构，优化电性传输路径，降低了回路寄生参数并减小了电磁干扰，提高器件的电性能，有效减少了器件的封装内阻，同时提高产品的可靠性；以及通过DBC正面覆铜结构，可以带来更大的散热面积，极大的提高了产品散热性能，有效降低了产品的工作结温；同时，通过DBC正面、背面覆铜结构，灵活调整覆铜厚度和覆铜面积大小，可以调整热传导通路截面和散热面积，从而灵活匹配不同性能需求的产品，实现低成本适配更多类型的产品。
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Figure CN122995646A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor power device packaging and manufacturing technology, and in particular to a packaging structure that achieves double-sided heat dissipation. Background Technology
[0002] With the rapid development of electric vehicles, high-voltage power transmission and other fields, higher requirements are being placed on power semiconductor devices. The main development paths are: higher power density, smaller package size, stronger thermal management capabilities, high-efficiency electrical transmission rate and higher product reliability level.
[0003] Traditional surface-mount power devices typically employ rear-side heat dissipation, with electrodes on the front of the chip led out via metal bonding wires. Heat can only be conducted through a single path on the back, resulting in high overall thermal resistance. Furthermore, the metal bonding wires exhibit significant parasitic inductance and resistance, which can easily cause electromagnetic interference and voltage overshoot during high-frequency switching, severely limiting the device's electrical performance and heat dissipation capabilities. Currently, to address these issues, the industry has introduced double-sided heat dissipation packaging technology. This technology uses a copper clip (CLIP) to replace the bonding wires, and after packaging, the top of the product is ground to expose the copper clip, achieving double-sided heat dissipation.
[0004] However, existing CLIP double-sided thermal packaging processes are prone to defects such as copper sheet misalignment and poor positioning accuracy during reflow soldering. Matching limiting structures or fixtures will increase costs and reduce production capacity. Moreover, due to structural limitations, full copper sheet bonding cannot be achieved, resulting in bottlenecks in the electrical performance and reliability of the products. Summary of the Invention
[0005] This application aims to at least solve the technical problems existing in the prior art. To this end, the first aspect of this application proposes a packaging structure for achieving double-sided heat dissipation, comprising: a lead frame, a chip, a die-attach material, a double-sided ceramic copper-clad laminate, and a molding resin; wherein: The lead frame has a recessed structure, and the chip and the double-sided ceramic copper-clad board are embedded in the recessed structure. The chip and the double-sided ceramic copper-clad board are bonded and fixed by adhesive material, and the copper cladding on the back of the double-sided ceramic copper-clad board is directly connected to the chip and the lead frame by solder. The sidewall of the ceramic substrate in the middle of the double-sided ceramic copper-clad laminate and the sidewall of the lead frame recess structure form a mutual limiting structure in the left, right and up directions. The sidewall of the G-pole copper-clad sheet and the S-pole copper-clad sheet of the double-sided ceramic copper-clad laminate and the sidewall of the corresponding lead frame G-pole lead and S-pole lead bend step form a mutual limiting structure in the downward direction. The molding resin is used to encapsulate the product. After grinding the molding resin, the top copper-clad sheet is exposed, which serves as the top heat sink of the product. The top copper-clad sheet is the front copper clad of a double-sided ceramic copper-clad board.
[0006] In one possible implementation, chip drain solder paste is disposed in the recessed structure, and the chip is disposed on top of the chip drain solder paste; chip drain is disposed on the back side of the chip, and chip drain is connected to chip drain solder paste; chip sink and chip gate are disposed on the front side of the chip; chip sink solder paste is disposed on top of chip sink and chip gate solder paste is disposed on top of chip gate; wherein, the area of chip drain solder paste is the same as the size of the chip.
[0007] In one possible implementation, the thickness of the D-type solder paste, S-type solder paste, G-type solder paste, S-type pin solder paste, and G-type pin solder paste is set to 30µm.
[0008] In one possible implementation, the copper plating on the back of the double-sided ceramic copper-clad board is used to directly connect the S-pin of the chip to the S-pin of the lead frame via solder, and the G-pin of the chip is directly connected to the G-pin of the lead frame; wherein, S-pin solder paste is provided above the S-pin, G-pin solder paste is provided above the G-pin, and the tops of the D-pin solder paste, the tops of the S-pin solder paste, and the tops of the G-pin solder paste are on the same horizontal plane.
[0009] In one possible implementation, a copper-clad sheet is placed above the solder paste for the S-polarity of the chip and the solder paste for the S-polarity pin, thereby directly connecting the S-polarity of the chip to the S-polarity pin; a copper-clad sheet is placed above the solder paste for the G-polarity of the chip and the solder paste for the G-polarity pin, thereby directly connecting the G-polarity of the chip to the G-polarity pin; wherein the size of the copper-clad sheet for the S-polarity is adjusted according to the area of the S-polarity of the chip, and the size of the copper-clad sheet for the G-polarity is adjusted according to the area of the G-polarity of the chip.
[0010] In one possible implementation, the S-pin is connected to the S-lead, and a bend step is provided at the connection point so that the S-pin is lower than the S-lead; the G-pin is connected to the G-lead, and a bend step is provided at the connection point so that the G-pin is lower than the G-lead.
[0011] In one possible implementation, the bottom surface of the central ceramic substrate is connected to the S-copper clad sheet and the G-copper clad sheet, and the top surface of the central ceramic substrate is connected to the top copper clad sheet.
[0012] In one possible implementation, the top surface of the central ceramic substrate is disposed on the same horizontal plane as the upper surface of the lead frame, so that the central ceramic substrate is embedded in the recess of the lead frame, and the three sides of the central ceramic substrate are provided with a gap of 0.05 mm from the sidewall of the recess structure.
[0013] In one possible implementation, a 0.05mm gap is provided between the sides of the G-copper clad sheet and the sides of the corresponding G-lead and S-lead bend steps.
[0014] In one possible implementation, the distance between the side of the chip and the sidewall of the pit structure is greater than or equal to 500 μm, and the depth of the pit structure is determined based on the combined thickness of the D-type solder paste, the S-type solder paste, the chip thickness, the S-type copper clad laminate thickness, and the ceramic substrate thickness.
[0015] The embodiments of this application have the following beneficial effects: This application provides a packaging structure for achieving double-sided heat dissipation, including: a lead frame, a chip, a die-attach material, a double-sided ceramic copper-clad laminate, and a molding resin; wherein, the lead frame has a recessed structure, the chip and the double-sided ceramic copper-clad laminate are embedded in the recessed structure, the chip and the double-sided ceramic copper-clad laminate are bonded and fixed by the die-attach material, and the copper cladding on the back of the double-sided ceramic copper-clad laminate is directly connected to the lead frame by solder; the sidewall of the ceramic substrate in the middle of the double-sided ceramic copper-clad laminate and the sidewall of the recessed structure of the lead frame, the sidewall of the G-pole copper cladding and S-pole copper cladding of the double-sided ceramic copper-clad laminate and the sidewall of the bent step of the G-pole lead and S-pole lead of the lead frame form a mutual limiting structure, which is used to limit the double-sided ceramic copper-clad laminate; the molding resin is used to encapsulate the product, and after grinding the molding resin, the top copper cladding is exposed, and the top copper cladding serves as the top heat sink of the product; wherein, the top copper cladding is the front copper cladding of the double-sided ceramic copper-clad laminate. This solution utilizes a specific leadframe structure design, combined with a universal DBC structure, to limit the DBC's position, resolving DBC drift and cornering issues. Compared to existing technologies, it offers lower material and packaging costs. Furthermore, by embedding the chip and DBC into the recessed structure of the leadframe, a smaller package thickness can be achieved, reducing package size and increasing power density. Additionally, the copper-clad structure on the back of the DBC replaces copper wires, enabling a full copper sheet bonding package structure. This optimizes the electrical transport path, reduces circuit parasitic parameters and electromagnetic interference, improves device electrical performance, effectively reduces package internal resistance, and enhances product reliability. The copper-clad structure on the front of the DBC provides a larger heat dissipation area, significantly improving heat dissipation performance and effectively reducing the product's operating junction temperature. Moreover, the copper-clad structures on the front and back of the DBC allow for flexible adjustment of the copper thickness and area, enabling adjustments to the heat conduction path cross-section and heat dissipation area. This allows for flexible matching of products with different performance requirements, achieving low-cost adaptation to a wider range of product types. Attached Figure Description
[0016] Figure 1 A schematic diagram of a lead frame solder paste coating structure provided in an embodiment of this application; Figure 2 This is a schematic diagram of a lead frame chip mounting structure provided in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the application of solder paste to a lead frame for chip mounting and to the pins, as provided in an embodiment of this application. Figure 4 This application provides a schematic diagram of a lead frame chip mounting and DBC copper sheet structure. Figure 5 This application provides an overall structural diagram of a lead frame chip mounting and DBC. Figure 6 A top view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 7 A side view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 8 A partial enlarged side view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 9 An image of a product after plastic sealing is provided as an embodiment of this application; Figure 10 This is a product appearance diagram after grinding, provided as an embodiment of this application.
[0017] Explanation of reference numerals in the attached figures: 1-Lead frame; 1-1-Upper surface of lead frame; 1-2-Side wall of lead frame recess; 1-3-G pin; 1-4-G lead; 1-5-S pin; 1-6-S lead; 1-7-Lead bend step; 1-8-Recess structure; 1-9-Top notch; 2-1 ~ Chip drain solder paste; 2-2 ~ Chip source solder paste; 2-3 ~ Chip gate solder paste; 2-4 ~ Gate pin solder paste; 2-5 ~ Source pin solder paste; 3 ~ Chip; 3-1 ~ Chip's S terminal; 3-2 ~ Chip's G terminal; 3-3 ~ Chip's D terminal; 4-1 Double-sided ceramic copper-clad laminate; 4-2 Copper-clad sheet for S-electrode; 4-3 Ceramic substrate; 4-4 Top copper-clad sheet; 4-5 Bottom edge of copper-clad sheet for S-electrode; 4-6 Side of ceramic substrate; 4-7 Top surface of ceramic substrate; 5. Molding resin. Detailed Implementation
[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0019] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, the use of "based on" or "according to" implies openness and inclusiveness, because processes, steps, calculations, or other actions "based on" or "according to" one or more of the stated conditions or values may in practice be based on additional conditions or beyond the stated values.
[0020] The following combination Figures 1-9 This application provides a detailed description of a packaging structure for achieving double-sided heat dissipation. Figure 1 A schematic diagram of a lead frame solder paste coating structure provided in an embodiment of this application; Figure 2 This is a schematic diagram of a lead frame chip mounting structure provided in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the application of solder paste to a lead frame for chip mounting and to the pins, as provided in an embodiment of this application. Figure 4 This application provides a schematic diagram of a lead frame chip mounting and DBC copper sheet structure. Figure 5 This application provides an overall structural diagram of a lead frame chip mounting and DBC. Figure 6 A top view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 7 A side view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 8 A partial enlarged side view of a lead frame, solder paste, chip, and DBC provided for embodiments of this application; Figure 9 An image of a product after plastic sealing is provided as an embodiment of this application; Figure 10 This is a product appearance diagram after grinding, provided as an embodiment of this application.
[0021] This application provides a packaging structure for achieving double-sided heat dissipation, including: a lead frame (1), a chip (3), adhesive material (i.e., all solder paste), a double-sided ceramic copper-clad board (4) (Direct Copper Bonding, abbreviated as DBC), and molding resin (5). The lead frame (1) has recessed structures (1-8). The chip (3) and the double-sided ceramic copper-clad board (4) are embedded in the recessed structures (1-8). The chip (3) and the double-sided ceramic copper-clad board (4) are bonded and fixed by adhesive material, and the copper plating on the back of the double-sided ceramic copper-clad board (4) is directly connected to the lead frame (1) by solder. Through the structural design of the recessed structures (1-8) in the lead frame (1), the chip (3) and DBC are embedded and mounted in the recessed structures (1-8), thereby increasing the product's power density and heat dissipation capacity.
[0022] The sidewall of the central ceramic substrate (not shown) of the double-sided ceramic copper-clad laminate (4) and the sidewall of the lead frame recess structure (1-8) form a mutually restrictive structure in the left, right, and upper directions. The sidewalls of the G-electrode copper-clad sheet (4-2) and S-electrode copper-clad sheet (4-1) of the double-sided ceramic copper-clad laminate (4) and the sidewalls of the corresponding lead frame G-electrode lead (1-4) and S-electrode lead (1-6) bend steps form a mutually restrictive structure in the downward direction. Optionally, a 0.05mm gap is provided between the sidewalls of the G-electrode copper-clad sheet and the sidewalls of the corresponding G-electrode lead and S-electrode lead bend steps.
[0023] The molding resin (5) is used to encapsulate the product. After grinding the molding resin (5), the top copper clad sheet (4-4) is exposed. The top copper clad sheet (4-4) serves as the top heat sink of the product. The top copper clad sheet (4-4) is the front copper clad sheet of the double-sided ceramic copper clad board (4).
[0024] Please continue to refer to this. Figure 1 The lead frame (1) is a profile material, formed by stamping and etching. A top notch (1-9) is provided on the upper edge of the lead frame (1), and a recessed structure (1-8) is provided on the upper surface (1-1) of the lead frame. The recessed structure (1-8) is connected to the lower edge of the lead frame (1), and the recessed structure (1-8) and the lead frame (1) form the lead frame recessed sidewall (1-2) in the left, right and upper directions.
[0025] Please continue to refer to this. Figure 1The S-pin (1-5) is connected to the S-lead (1-6), and a bend step (1-7) is provided at the connection point so that the S-pin (1-5) is lower than the S-lead (1-6); the G-pin (1-3) is connected to the G-lead (1-4), and a bend step (1-7) is provided at the connection point so that the G-pin (1-3) is lower than the G-lead (1-4). Furthermore, the copper plating on the back of the double-sided ceramic copper-clad board (4) is soldered to directly connect the chip's S-pin (3-1) to the S-pin (1-5) of the lead frame (1), and the chip's G-pin (3-2) to the G-pin (1-3) of the lead frame (1).
[0026] In some alternative embodiments, such as Figures 1-3 As shown, chip drain solder paste (2-1) is placed in the recessed structure (1-8), and chip (3) is placed above chip drain solder paste (2-1). Chip S solder paste (2-2) is placed above chip S electrode (3-1), and chip G solder paste (2-3) is placed above chip G electrode (3-2). S electrode pin solder paste (2-5) is placed above S electrode pin (1-5), and G electrode pin solder paste (2-4) is placed above G electrode pin (1-3).
[0027] Among them, the area of the chip D electrode solder paste (2-1) is the same as the size of the chip (3). The size of the chip (3) is smaller than the size of the pit structure (1-8), which can ensure the feasibility of solder paste dispensing and chip mounting process and guarantee the quality of chip mounting.
[0028] In some alternative embodiments, the distance between the side of the chip (3) and the sidewall of the pit structure (1-8) is greater than or equal to 500 μm.
[0029] Furthermore, the thickness of the aforementioned solder paste can be set according to actual needs. Optionally, the thickness of the D-type solder paste, S-type solder paste, and G-type solder paste can be set to 30µm. That is, the thickness of the chip D-type solder paste (2-1), chip S-type solder paste (2-2), chip G-type solder paste (2-3), S-type pin solder paste (2-5), and G-type pin solder paste (2-4) can be set to 30µm.
[0030] Alternatively, please continue to refer to Figure 1 The top of the chip's D-pin solder paste (2-1), the top of the S-pin solder paste (2-5), and the top of the G-pin solder paste (2-4) are set on the same horizontal plane.
[0031] In some alternative embodiments, a chip D electrode (3-3) is disposed on the back side of the chip (3), and the chip D electrode (3-3) is connected to the chip D electrode solder paste (2-1); a chip S electrode (3-1) and a chip G electrode (3-2) are disposed on the front side of the chip (3).
[0032] like Figure 3-4 As shown, a copper-clad sheet (4-1) is placed above the solder paste (2-2) for the S-polarity and the solder paste for the S-polarity pin (2-5) of the chip. The copper-clad sheet (4-1) directly connects the S-polarity (3-1) of the chip to the S-polarity pin (1-5). A copper-clad sheet (4-2) is placed above the solder paste (2-3) for the G-polarity and the solder paste for the G-polarity pin (2-4) of the chip. The copper-clad sheet (4-2) directly connects the G-polarity (3-2) of the chip to the G-polarity pin (1-3). The size of the copper-clad sheet (4-1) is adjusted according to the size of the S-polarity (3-1) of the chip, and the size of the copper-clad sheet (4-2) is adjusted according to the size of the G-polarity (3-2) of the chip.
[0033] In addition, a 0.05mm gap is set between the bottom edge of the S-electrode copper-clad sheet (4-5) and the lead bending step (1-7) to limit the DBC downward. Furthermore, the copper thickness of the S-electrode copper-clad sheet (4-1) is designed to be greater than the thickness of the lead bending step (1-7) to ensure that a gap is left between the ceramic substrate (4-3) and the G-electrode lead (1-4) and the S-electrode lead (1-6).
[0034] like Figure 5 As shown, the bottom surface of the central ceramic substrate is connected to the S-copper clad sheet (4-1) and the G-copper clad sheet (4-2), and the top surface of the central ceramic substrate is connected to the top copper clad sheet (4-4). By designing the ceramic substrate and the top copper clad sheet, the thickness and size can be adjusted according to the product thickness, product performance, and heat dissipation requirements, thus adapting to different levels of product packaging capabilities. Furthermore, the top surface of the central ceramic substrate and the upper surface of the lead frame are set at the same horizontal plane, so that the central ceramic substrate is embedded in the lead frame recess, and the three sides of the central ceramic substrate are separated from the sidewalls of the recess structure by a gap of 0.05mm.
[0035] In addition, a 0.05mm gap is provided between the side of the ceramic substrate (4-6) and the side wall of the recess structure (1-8). The three sides of the ceramic substrate (4-3) cooperate with the side wall (1-2) of the lead frame recess to limit the double-sided ceramic copper-clad board (4) to the left, right and upward directions.
[0036] Furthermore, by setting the top surface (4-7) of the ceramic substrate and the upper surface of the lead frame (1) carrier on the same plane, it can be ensured that the lead frame (1) is completely encapsulated in the molding resin (5) after grinding.
[0037] Optionally, the S-copper clad sheet (4-1) and the G-copper clad sheet (4-2) can be adjusted arbitrarily according to the thickness of the chip (3) and the layout of the chip (3), so as to adapt to different types and sizes of chips (3) at low cost.
[0038] In this embodiment, a 0.05mm fit gap is designed between the side of the ceramic substrate (4-6) and the side wall of the lead frame recess (1-2), and a 0.05mm fit gap is designed between the bottom edge of the S-pole copper-clad sheet (4-5) and the side of the lead bend step (1-7). This limits the angular offset of the DBC and ensures the mounting accuracy of the DBC. At the same time, the ceramic substrate (4-3) serves as an insulating material, and the contact position between the DBC and the lead frame (1) is insulated, thus realizing the circuit transmission function of the product.
[0039] like Figure 6 and Figure 7 As shown, the lead frame (1) and the double-sided ceramic copper-clad board (4) cooperate with each other to limit the double-sided ceramic copper-clad board (4) in the four directions of left, right, up and down in the XY plane, ensuring that the double-sided ceramic copper-clad board (4) has no rotation or offset.
[0040] like Figure 8 As shown, Figure 8 for Figure 7 The enlarged view at point A shows that the depth of the pit structure (1-8) in the lead frame (1) is determined based on the thickness of the chip D electrode solder paste (2-1), the chip S electrode solder paste (2-2), the chip (3), the S electrode copper clad sheet (4-1), and the ceramic substrate (4-3).
[0041] Optionally, the depth of the recess structure (1-8) can be set to the sum of the thickness of the chip D electrode solder paste (2-1), the chip S electrode solder paste (2-2), the chip (3), the S electrode copper clad sheet (4-1), and the ceramic substrate (4-3), thereby ensuring that the top copper clad sheet (4-4) is higher than the upper surface of the lead frame (1) carrier.
[0042] like Figure 9 As shown, the product is encapsulated with encapsulating resin (5). After encapsulation, the upper surface of the encapsulating resin (5) is ground downwards through a grinding process until the top copper sheet (4-4) is exposed. The top copper sheet (4-4) is set as the heat sink on the top of the product to realize the heat dissipation function of the top of the product.
[0043] Based on the above-described packaging structure for achieving double-sided heat dissipation, this application embodiment also provides a packaging process for packaging a power MOSFET, including the following steps: 1. The chip mounting machine applies solder paste (2-1) to the chip drain electrode on the upper surface of the recessed structure (1-8).
[0044] 2. The chip placement machine picks up the chip (3) and places it on the upper surface of the chip's D electrode solder paste (2-1).
[0045] 3. The pick-and-place machine applies chip S-terminal solder paste (2-2) to the upper surface of the chip's S-terminal (3-1), applies chip G-terminal solder paste (2-3) to the upper surface of the chip's G-terminal (3-2), applies G-terminal solder paste (2-4) to the upper surface of the G-terminal pin (1-3), and applies S-terminal solder paste (2-5) to the upper surface of the S-terminal pin (1-5).
[0046] 4. The pick-and-place machine picks up the DBC and places the S-terminal copper-clad sheet (4-1) on the bottom surface of the DBC onto the upper surface of the chip's S-terminal solder paste (2-2) and S-terminal pin solder paste (2-5). Then, it places the G-terminal copper-clad sheet (4-2) on the bottom surface of the DBC onto the upper surface of the chip's G-terminal solder paste (2-3) and G-terminal pin solder paste (2-4).
[0047] 5. Place the assembled lead frame (1) + solder paste + chip (3) + DBC into a vacuum reflow oven for solder paste reflow soldering, and then perform ultrasonic solder paste cleaning after reflow soldering. 6. After cleaning, the product is sealed in plastic.
[0048] 7. Grind the molded product, grinding the upper surface of the molding resin (5) downwards until the top copper sheet (4-4) is exposed.
[0049] 8. After grinding, the entire product continues to undergo processes such as rib cutting and testing.
[0050] This application provides a packaging structure for achieving double-sided heat dissipation, including: a lead frame, a chip, a die-attach material, a double-sided ceramic copper-clad laminate, and a molding resin; wherein, the lead frame has a recessed structure, the chip and the double-sided ceramic copper-clad laminate are embedded in the recessed structure, the chip and the double-sided ceramic copper-clad laminate are bonded and fixed by the die-attach material, and the copper cladding on the back of the double-sided ceramic copper-clad laminate is directly connected to the lead frame by solder; the sidewall of the ceramic substrate in the middle of the double-sided ceramic copper-clad laminate and the sidewall of the recessed structure of the lead frame, the sidewall of the G-pole copper cladding and S-pole copper cladding of the double-sided ceramic copper-clad laminate and the sidewall of the bent step of the G-pole lead and S-pole lead of the lead frame form a mutual limiting structure, which is used to limit the double-sided ceramic copper-clad laminate; the molding resin is used to encapsulate the product, and after grinding the molding resin, the top copper cladding is exposed, and the top copper cladding serves as the top heat sink of the product; wherein, the top copper cladding is the front copper cladding of the double-sided ceramic copper-clad laminate. This solution utilizes a specific leadframe structure design, combined with a universal DBC structure, to limit the DBC's position, resolving DBC drift and cornering issues. Compared to existing technologies, it offers lower material and packaging costs. Furthermore, by embedding the chip and DBC into the recessed structure of the leadframe, a smaller package thickness can be achieved, reducing package size and increasing power density. Additionally, the copper-clad structure on the back of the DBC replaces copper wires, enabling a full copper sheet bonding package structure. This optimizes the electrical transport path, reduces circuit parasitic parameters and electromagnetic interference, improves device electrical performance, effectively reduces package internal resistance, and enhances product reliability. The copper-clad structure on the front of the DBC provides a larger heat dissipation area, significantly improving heat dissipation performance and effectively reducing the product's operating junction temperature. Moreover, the copper-clad structures on the front and back of the DBC allow for flexible adjustment of the copper thickness and area, enabling adjustments to the heat conduction path cross-section and heat dissipation area. This allows for flexible matching of products with different performance requirements, achieving low-cost adaptation to a wider range of product types.
[0051] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.
[0052] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.
Claims
1. A packaging structure for achieving double-sided heat dissipation, characterized in that, include: Leadframe, chip, die bonding material, double-sided ceramic copper-clad laminate, and molding resin; among which: The lead frame has a recessed structure, and the chip and the double-sided ceramic copper-clad laminate are embedded in the recessed structure. The chip and the double-sided ceramic copper-clad laminate are bonded and fixed by the adhesive material, and the copper cladding on the back of the double-sided ceramic copper-clad laminate is directly connected to the chip and the lead frame by solder. The sidewall of the ceramic substrate in the middle of the double-sided ceramic copper-clad laminate and the sidewall of the lead frame recess structure form a mutual limiting structure in the left, right and up directions. The sidewalls of the G-pole copper-clad sheet and S-pole copper-clad sheet of the double-sided ceramic copper-clad laminate and the sidewalls of the corresponding lead frame G-pole lead and S-pole lead bend step form a mutual limiting structure in the downward direction. The molding resin is used to encapsulate the product. After grinding the molding resin, a top copper-clad sheet is exposed, which serves as a heat sink on the top of the product. The top copper-clad sheet is the front copper clad of the double-sided ceramic copper-clad board.
2. The packaging structure for achieving double-sided heat dissipation according to claim 1, characterized in that, The recessed structure contains chip drain solder paste, with the chip positioned above the drain solder paste. A chip drain electrode is located on the back of the chip and connected to the drain solder paste. A chip sink electrode and a chip gate electrode are located on the front of the chip. S-type drain solder paste is located above the S-type drain electrode, and G-type drain solder paste is located above the G-type drain electrode. The area of the drain solder paste is the same as the size of the chip.
3. The packaging structure for achieving double-sided heat dissipation according to claim 2, characterized in that, The copper plating on the back of the double-sided ceramic copper-clad board is used to directly connect the S-pin of the chip to the S-pin of the lead frame via solder, and the G-pin of the chip is directly connected to the G-pin of the lead frame; wherein, S-pin solder paste is provided above the S-pin, and G-pin solder paste is provided above the G-pin, and the tops of the D-pin solder paste, the tops of the S-pin solder paste, and the tops of the G-pin solder paste are on the same horizontal plane.
4. The packaging structure for achieving double-sided heat dissipation according to claim 3, characterized in that, The thickness of the D-type solder paste, the S-type solder paste, the G-type solder paste, the S-type pin solder paste, and the G-type pin solder paste is set to 30µm.
5. The packaging structure for achieving double-sided heat dissipation according to claim 3 or 4, characterized in that, A copper-clad sheet is disposed above the solder paste for the S-polarity of the chip and the solder paste for the S-polarity pin, thereby directly connecting the S-polarity of the chip to the S-polarity pin; a copper-clad sheet is disposed above the solder paste for the G-polarity of the chip and the solder paste for the G-polarity pin, thereby directly connecting the G-polarity of the chip to the G-polarity pin; wherein, the size of the copper-clad sheet for the S-polarity is adjusted according to the area of the S-polarity of the chip, and the size of the copper-clad sheet for the G-polarity is adjusted according to the area of the G-polarity of the chip.
6. The packaging structure for achieving double-sided heat dissipation according to claim 5, characterized in that, The S-pin is connected to the S-lead, and a bend step is provided at the connection point so that the S-pin is lower than the S-lead; the G-pin is connected to the G-lead, and a bend step is provided at the connection point so that the G-pin is lower than the G-lead.
7. The packaging structure for achieving double-sided heat dissipation according to claim 5, characterized in that, The bottom surface of the central ceramic substrate is connected to the S-electrode copper-clad sheet and the G-electrode copper-clad sheet, and the top surface of the central ceramic substrate is connected to the top copper-clad sheet.
8. The packaging structure for achieving double-sided heat dissipation according to any one of claims 1-4, characterized in that, The top surface of the central ceramic substrate is on the same horizontal plane as the upper surface of the lead frame, so that the central ceramic substrate is embedded in the recess of the lead frame, and the three sides of the central ceramic substrate are separated from the sidewall of the recess structure by a gap of 0.05mm.
9. The packaging structure for achieving double-sided heat dissipation according to any one of claims 1-4, characterized in that, A 0.05mm gap is provided between the side of the G-electrode copper clad sheet and the side of the corresponding G-electrode lead and the bend step of the S-electrode lead.
10. The packaging structure for achieving double-sided heat dissipation according to any one of claims 1-4, characterized in that, The distance between the side of the chip and the sidewall of the recess structure is greater than or equal to 500 μm, and the depth of the recess structure is determined based on the thickness of the D-type solder paste, the S-type solder paste, the chip thickness, the S-type copper clad laminate thickness, and the ceramic substrate thickness.