Heat conduction structure of thermoelectric separation printed circuit board

Abstract

The utility model provides a heat conduction structure of a thermoelectric separation printed circuit board. A bump structure is formed on a heat-conducting metal block through methods of electroplating addition, mechanical turn-milling, pattern corrosion and the like, then the bump structure is laminated with a prepreg and a copper foil, and pattern transfer is performed to obtain the conductive pattern of the printed circuit board. A bump designed below the power device is exposed through the aspects of laser, depth-controlled milling and the like to construct a heat conduction channel. According to the utility model, the defects of high heat transfer efficiency, low wiring density and the like caused by secondary heat transfer when a conventional thermoelectric separation printed circuit board dissipates heat through through holes are overcome.

Description

Technical Field

[0001] This utility model belongs to the field of printed circuit manufacturing technology, and relates to high-power printed circuit board products used in new energy vehicles and other fields. In particular, it relates to a heat-conducting structure for a thermoelectric separation printed circuit board. Technical Background

[0002] Printed circuit boards (PCBs), due to their role in carrying current and controlling large current volumes, must possess good thermal conductivity. In high-power devices such as those used in new energy vehicles, thermoelectric separation structures are employed. This involves carrying current through a resin substrate and attaching a copper block to it to form a heat dissipation layer, a crucial method for solving high-power heat dissipation in PCBs. However, because the resin current-carrying layer and copper must be bonded together using resin adhesives, the low thermal conductivity of the resin adhesives drastically reduces the thermal conductivity of the resin substrate.

[0003] To address this, the industry practice typically involves drilling holes in the resin using controlled-depth milling, followed by copper electroplating and filling with thermally conductive adhesive to create heat conduction channels, effectively improving the thermal conductivity of the printed circuit board. However, this method has several drawbacks. Firstly, the large number of thermally conductive holes on the printed circuit board reduces the effective circuit area, resulting in lower circuit density. Secondly, the incompatibility between the thermally conductive adhesive and the copper plating leads to low product yield and impacts production efficiency.

[0004] This invention proposes a method for constructing a heat conduction channel by laminating heat dissipation metal block bumps. By designing the heat conduction bumps below high-power devices, the area of ​​the printed circuit board can be saved, and the heat conduction channel can be constructed most effectively. Summary of the Invention

[0005] This invention proposes a novel method for constructing heat conduction channels on thermoelectrically separated printed circuit boards. This method involves directly designing heat dissipation bumps below the heat source—the power device. The heat dissipation bumps and the heat-conducting metal block are integrated into a single structure, thus enabling the heat source to directly act on the heat dissipation metal module, achieving the highest heat dissipation efficiency.

[0006] This invention provides a thermally conductive structure for a thermoelectrically separated printed circuit board. The structure involves fabricating heat-dissipating bumps on a copper heat-dissipating block, simultaneously laminating them with the prepreg and copper foil of the printed circuit board, piercing the prepreg and embedding the bumps within it, and then exposing the bumps using methods such as resin chipping, thus constructing a thermally conductive channel for the heat-dissipating bumps under high-power devices.

[0007] The installation position of the heat dissipation bumps needs to be designed in advance according to the design requirements of the power devices. Generally, the heat dissipation bumps are located below the power devices, which can directly conduct the heat from the power devices to the heat dissipation bumps, and then to the heat sink, achieving efficient heat dissipation.

[0008] During lamination, the height of the heat dissipation bumps is smaller than the thickness of the prepreg. After lamination and curing, the bumps are embedded inside the prepreg to prevent them from piercing the copper foil and affecting the adhesion of the printed circuit board surface traces. To expose the heat dissipation bumps, deep milling and laser cutting are used to remove excess resin from the bumps.

[0009] The convex structure formed on the heat dissipation metal block can be obtained through methods such as electroplating, machining, and pattern etching, depending on the type of material and the thickness of the bump. Furthermore, the bump and the heat dissipation metal can be made of either the same or different metal materials.

[0010] Currently, thermoelectric separation printed circuit boards (PCBs) use methods such as electroplated through-holes and filling through-holes with conductive adhesive to construct heat conduction channels. This method requires a secondary heat transfer process: the power chip transfers heat to the through-hole area, and the through-hole then transfers the heat to the heat sink. This heat dissipation method is not only inefficient, but the presence of thermal adhesive also leads to low PCB reliability. Furthermore, the presence of numerous heat dissipation through-holes occupies significant area and volume on the PCB, hindering high-density PCB design. This invention addresses the shortcomings of conventional thermoelectric separation PCBs, such as low heat transfer efficiency and low wiring density due to secondary heat transfer via through-holes, achieving a more efficient heat dissipation goal. Attached Figure Description

[0011] Figure 1 It features an integrated structure of heat dissipation metal and heat dissipation bumps;

[0012] Figure 2 This is the structure formed by laminating heat dissipation bumps, prepreg, and copper foil.

[0013] Figure 3 This is the structure after the printed circuit pattern is transferred following lamination;

[0014] Figure 4 This describes the structure after the resin layer of a printed circuit board is chipped to expose the bumps.

[0015] Figure 5 A schematic diagram of the structure for heat dissipation after high-power devices are installed;

[0016] Figure reference numerals: 101-Heat dissipation metal and bumps, 102-Semi-cured (resin layer), 103-Copper circuit layer, 104-High-power device. Detailed Implementation Plan

[0017] A thermally conductive structure for a thermoelectrically separated printed circuit board, characterized by comprising the following steps:

[0018] Bumps are machined onto the surface of a 3mm thick copper heat sink using a machining method. After machining, the thickness of the heat sink layer is 2mm, and the height of the heat sink bump is 1mm. This implementation scheme designs 4 heat sink bumps, each with dimensions of 2mm × 4mm.

[0019] Eighteen 1080 semi-cured laminates are laminated with 35μm thick copper foil and bumps to form a copper-clad printed circuit board structure with bumps.

[0020] Conductive patterns on the surface of a printed circuit board are created through processes such as dry film lamination, exposure, development, and etching. In this process, the copper in the heat dissipation bump area is etched away.

[0021] After the solder mask is applied, a laser is used to remove the resin from the area, exposing the bumps. A gold protective layer is then deposited on the bumps using a chemical nickel-gold process to prevent copper oxidation.

Claims

1. A thermally conductive structure for a thermoelectrically separated printed circuit board, characterized in that, By fabricating heat dissipation bumps on a heat dissipation metal block and laminating them with a printed circuit board to pierce the prepreg, a heat-conducting structure is formed under the heat dissipation bumps of a high-power device. The heat dissipation bumps are located under the high-power device, and the high-power device conducts heat to the copper block through the heat dissipation bumps, thus constructing an effective heat conduction channel.

2. The thermally conductive structure of the thermoelectric separation printed circuit board according to claim 1, characterized in that, During the lamination process of copper block, prepreg, and copper foil, the heat dissipation bump pierces the prepreg and achieves curing.

3. The thermally conductive structure of the thermoelectrically separated printed circuit board according to claim 1, characterized in that... The height of the heat dissipation bumps is smaller than the thickness of the prepreg.

4. The thermally conductive structure of the thermoelectrically separated printed circuit board according to claim 1, characterized in that, After pressing, the surface copper foil is etched into conductive patterns according to the printed circuit board pattern transfer process. Then, the excess resin on the heat dissipation bumps is removed by laser ablation or controlled depth milling to obtain the exposed conductive patterns.

5. The thermally conductive structure of the thermoelectrically separated printed circuit board according to claim 1, characterized in that, Heat dissipation bumps can be obtained by any of the following methods: electroplating, mechanical milling, or graphic etching.

6. The thermally conductive structure of the thermoelectrically separated printed circuit board according to claim 1, characterized in that, The heat dissipation bumps can be made of the same metal material or different metal materials.

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