Single-side multi-layer copper-based boss thermoelectric separation printed board preparation process

Abstract

The invention provides a single-side multi-layer copper-based boss thermoelectric separation printed board preparation technology. The technology comprises the following steps: S1, copper-based boss manufacturing: material taking, drilling, resin hole plugging, baking, grinding, protective film pasting, circuit pretreatment, solder resist ink printing, pre-baking, LED exposure, developing, etching, cleaning and drying, and resin grinding; s2, multi-layer board manufacturing: performing FR-4 board cutting, inner layer patterning, DES, AOI, pressing, target drilling, hole drilling, copper deposition, board electroplating, resin hole plugging, baking, grinding, outer layer L1 circuit manufacturing, etching, AOI, boss position numerical control windowing, cleaning and drying; and S3, laminating the copper-based boss in the step S1 and the multi-layer board in the step S2, then removing the film, manufacturing an outer layer L4 layer circuit, etching, performing AOI, performing resistance welding, writing, performing nickel gold immersion, drilling a copper-based position resin hole, and forming. According to the preparation process of the single-side multi-layer copper-based boss thermoelectric separation printed board, the alkaline etching copper reduction technology, the circuit forming pre-compensation technology and the mixed compression technology are combined, the embedding degree of the boss can be improved, and meanwhile the problem of glue overflowing of the boss is effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit boards, and in particular to a preparation process of a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board. Background Art

[0002] With the widespread use of LEDs, high-power LEDs cannot meet their heat dissipation needs by using traditional heat dissipation media + metal-based structures. Thermoelectric separation circuit boards are used in this environment. They have separate heat channel pads, which are completely insulated from the LED chip, gold wire, bracket, electrical pins, etc., and can connect the heat dissipation pads on the entire PCB to maximize the use of limited heat dissipation area.

[0003] Invention patent application CN 117794081 A discloses a method for manufacturing a double-layer single-sided copper-based thermoelectric separation substrate, which relates to the field of thermoelectric separation substrate manufacturing, and specifically includes the following manufacturing steps: Step 1, material preparation, preparing a suitable thin substrate for backup; Step 2, pretreatment, drilling holes at designated positions on the surface of the prepared thin substrate, and performing copper deposition and full-board electroplating on the thin substrate; Step 3, copper surface treatment, performing whole-board dry film protection treatment on the first copper surface, and the first copper surface is used as the LED surface, and the second copper surface is exposed and developed until the pattern is revealed, and acid etching is performed, and then the thin substrate is browned.

[0004] The existing thermoelectric separation printed circuit board has the following problems: 1. The boss is prone to glue overflow, and the joint between copper and FR-4 board is prone to short circuit; 2. The core board and the copper-based boss have poor fit and are prone to offset. Summary of the invention

[0005] In order to make up for the deficiencies in the prior art, the present invention provides a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board preparation process, which combines alkaline etching copper reduction technology, circuit forming pre-compensation technology, and mixed pressing technology to improve the fit of the boss and effectively avoid the problem of boss glue overflow.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A single-sided multi-layer copper-based boss thermoelectric separation printed circuit board preparation process comprises the following steps:

[0008] S1. Copper-based boss production: material collection, drilling, resin plugging, baking, grinding, protective film application, circuit pre-treatment, solder resist ink printing, pre-baking, LED exposure, development, etching, cleaning and drying, and resin grinding; in the solder resist ink printing process, the boss compensation amount is increased by 300μm on one side; in the etching process, the vacuum etcher is used to reduce the copper by 510-520μm;

[0009] S2. Multilayer board production: FR-4 board cutting, inner layer graphics, DES, AOI, lamination, drilling target, drilling, copper deposition, board electricity, resin plugging, baking, grinding, outer layer L1 circuit production, etching, AOI, CNC window opening of bosses, cleaning and drying; according to the position of the copper-based bosses in step S1, different proportions of pre-compensation are adopted in different layers, and the pre-compensation ratio is between 1 / 10,000 and 5 / 10,000;

[0010] S3. The copper-based boss of step S1 and the multilayer board of step S2 are pressed together. During the pressing process, a glass fiber prepreg and a glass fiber-free low-flow adhesive prepreg are combined. Then, the film is removed, the outer L4 layer circuit is made, etched, AOI, solder mask, text, nickel gold, copper base resin hole is drilled, and molding is performed.

[0011] Furthermore, in step S1, the boss surface is rotated downward during the vacuum etching process and the etching is performed four times.

[0012] Furthermore, in step S1, the drilling process is processed using a double-edged special tool with a diameter of 3.0 mm, and alcohol is used to dissipate heat during the processing.

[0013] Furthermore, in step S2, the inner layer pattern is pre-compensated by 0.5%, the outer layer L1 circuit and FR-4 drilling layer are pre-compensated by 0.2%, and the square groove is pre-compensated by 0.1%.

[0014] Furthermore, in step S2, the FR-4 board is selected to have a TG ≥ 170°C.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects:

[0016] The present invention adopts alkaline etching copper reduction technology in the process of manufacturing copper-based bosses, so that the copper bosses can be completely protruded, and then pre-compensation is performed on the circuit and the molding in the process of manufacturing the multi-layer board, so that each FR-4 can be matched with the copper base one by one, and the problems of boss embedding alignment and stress are perfectly solved; finally, the mixed pressing technology is adopted in the process of pressing the copper base and the multi-layer board, and the semi-cured sheet with low glue flow is attached to the FR-4. The characteristic of low glue flow is utilized to avoid glue overflow at the boss position. At the same time, the semi-cured sheet containing glass fiber has sufficient glue flow, which can well fill the gap around the copper-based boss, prevent the residue and erosion of the liquid medicine and dust, thereby avoiding the defects caused by the short circuit of the product. DETAILED DESCRIPTION

[0017] Many specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from the description, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] A single-sided multi-layer copper-based boss thermoelectric separation printed circuit board preparation process comprises the following steps:

[0019] S1.Copper-based boss production: material collection, drilling, resin plugging, baking, grinding, protective film application, circuit pre-treatment, solder mask ink printing, pre-baking, LED exposure, development, etching, cleaning and drying, grinding resin.

[0020] The drilling process uses a 3.0mm diameter double-edged special tool, and alcohol is used to dissipate heat during the processing process to improve the quality of the hole mouth and hole wall. The resin plugging process can prevent the formation of holes in the hole wall. In the solder mask ink printing process, the boss compensation amount is increased by 300μm on one side; in the etching process, under alkaline conditions, a vacuum etcher is used to reduce copper by 510-520μm to make the boss protrude completely; high temperature resistant photosensitive solder mask ink is used as the anti-corrosion layer, and the boss surface is placed downward during the etching process. After 4 etchings, the impact caused by the pool effect can be reduced to ensure the uniformity of the bite process.

[0021] S2. Multilayer board production: FR-4 board cutting, inner layer graphics, DES, AOI, lamination, drilling target, drilling, copper deposition, board electricity, resin plugging, baking, grinding, outer layer L1 circuit production, etching, AOI, boss CNC window opening, cleaning and drying.

[0022] For the position of the copper-based boss in step S1, the multilayer board is measured by two-dimensional measurement, and different proportions of pre-compensation are adopted in different layers, with the pre-compensation ratio ranging from 1 / 10,000 to 5 / 10,000; among them, the inner layer graphics are pre-compensated by 5 / 10,000, the outer layer L1 circuit and FR-4 drilling layer are pre-compensated by 2 / 10,000, and the square groove is compensated by 1 / 10,000. After the secondary pressing, the copper-based layer and the FR-4 layer size are perfectly matched. FR-4 boards are preferably made of boards with TG ≥ 170℃, and combined with the above-mentioned circuit and molding pre-compensation technology, each FR-4 is paired with the copper base one by one, which perfectly solves the problems of boss embedding alignment and stress.

[0023] S3. Press the copper-based boss of step S1 and the multilayer board of step S2. During the pressing process, a glass fiber prepreg and a glass fiber-free low-flow adhesive prepreg are used between the copper-based board and the multilayer board. Then, the film is removed, the outer L4 layer circuit is made, etched, AOI, solder mask, text, nickel-gold, copper-based resin holes are drilled, and molded. The molded products can be shipped after testing, finished product inspection, OSP, and packaging.

[0024] The lamination process uses mixed pressing technology, and uses a semi-cured sheet with low adhesive flow to stick to FR-4. The characteristics of low adhesive flow can prevent adhesive overflow on the boss. At the same time, the semi-cured sheet containing glass fiber has sufficient adhesive flow, which can well fill the gap around the copper-based boss to prevent the residue and erosion of chemicals and dust, thereby avoiding defects caused by product short circuits.

[0025] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. However, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A single-sided multi-layer copper-based boss thermoelectric separation printed circuit board preparation process, characterized in that: The following steps are involved: S1. Copper-based boss production: material collection, drilling, resin plugging, baking, grinding, protective film application, circuit pre-treatment, solder resist ink printing, pre-baking, LED exposure, development, etching, cleaning and drying, and resin grinding; in the solder resist ink printing process, the boss compensation amount is increased by 300μm on one side; in the etching process, the vacuum etcher is used to reduce the copper by 510-520μm; S2. Multilayer board production: FR-4 board cutting, inner layer graphics, DES, AOI, lamination, drilling target, drilling, copper deposition, board electricity, resin plugging, baking, grinding, outer layer L1 circuit production, etching, AOI, CNC window opening of bosses, cleaning and drying; according to the position of the copper-based bosses in step S1, different proportions of pre-compensation are adopted in different layers, and the pre-compensation ratio is between 1 / 10,000 and 5 / 10,000; S3. The copper-based boss of step S1 and the multilayer board of step S2 are pressed together. During the pressing process, a glass fiber prepreg and a glass fiber-free low-flow adhesive prepreg are combined. Then, the film is removed, the outer L4 layer circuit is made, etched, AOI, solder mask, text, nickel gold, copper base resin hole is drilled, and molding is performed.

2. The process for preparing a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board according to claim 1, characterized in that: In step S1, the boss surface is rotated downward during the vacuum etching process and the etching is performed four times.

3. The process for preparing a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board according to claim 2, characterized in that: In step S1, the drilling process is processed by using a double-edged special tool with a diameter of 3.0 mm, and alcohol is used for heat dissipation during the processing.

4. The process for preparing a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board according to claim 3, characterized in that: In step S2, the inner layer pattern is pre-compensated by 0.5%, the outer layer L1 circuit and FR-4 drilling layer are pre-compensated by 0.2%, and the square groove is pre-compensated by 0.1%.

5. The process for preparing a single-sided multi-layer copper-based boss thermoelectric separation printed circuit board according to claim 4, characterized in that: In step S2, the FR-4 board is selected to have a TG ≥ 170°C.