阅读说明：本技术 一种无底铜电路板的制作方法 (Method for manufacturing bottomless copper circuit board ) 是由 胡小义 黄明安 何小国 于 2019-11-14 设计创作，主要内容包括：本发明公开了一种无底铜电路板的制作方法，包括以下步骤：按拼板尺寸开出无铜基板，并对无铜基板进行退火处理；而后对无铜基板依次进行研磨、喷砂及火山灰磨板处理；依次通过沉铜和全板电镀在无铜基板表面镀上铜层，形成覆铜板；采用负片工艺或正片工艺在覆铜板上制作内、外层线路；而后依次在覆铜板上制作阻焊层、表面处理和成型，制得电路板。本发明方法通过物理加化学的粗化方法，提高了无铜基板表面的附着力，确保电镀铜层与基材牢固结合。(The invention discloses a method for manufacturing a bottomless copper circuit board, which comprises the following steps: cutting a copper-free substrate according to the size of the jointed board, and annealing the copper-free substrate; then sequentially grinding, sand blasting and volcanic ash plate grinding treatment are carried out on the copper-free substrate; sequentially carrying out copper deposition and full-plate electroplating to plate a copper layer on the surface of the copper-free substrate to form a copper-clad plate; manufacturing inner and outer layer circuits on the copper-clad plate by adopting a negative film process or a positive film process; and then sequentially manufacturing a solder mask layer, surface treatment and molding on the copper-clad plate to obtain the circuit board. The method improves the adhesive force of the surface of the copper-free substrate by a physical and chemical roughening method, and ensures that the electroplated copper layer is firmly combined with the base material.)

1. A method for manufacturing a bottomless copper circuit board is characterized by comprising the following steps:

s1, cutting a copper-free substrate according to the size of the jointed board, and annealing the copper-free substrate;

s2, sequentially grinding, sand blasting and volcanic ash plate grinding treatment are carried out on the copper-free substrate;

s3, sequentially carrying out copper deposition and full-plate electroplating on the surface of the copper-free substrate to plate a copper layer to form a copper-clad plate;

s4, manufacturing inner and outer layer circuits on the copper-clad plate by adopting a negative film process or a positive film process;

and S5, sequentially manufacturing a solder mask layer on the copper-clad plate, and performing surface treatment and molding to obtain the circuit board.

2. The method of claim 1, wherein the annealing is performed at a temperature higher than the TG temperature of the copper-free substrate for 2h in step S1.

3. The method for manufacturing a bottomless copper circuit board according to claim 1, wherein in step S2, a 600-mesh abrasive belt is used to grind the copper-free substrate.

4. The method of claim 3, wherein the pressures of the grinding, sand blasting and volcanic ash plate polishing in step S2 are all 2.5 ± 0.5kg/cm²。

5. The method of claim 1, further comprising the steps of, between steps S2 and S3:

and S21, performing glue removing treatment on the copper-free substrate.

6. The method of claim 1, wherein in step S3, the copper-free substrate is first subjected to three times of copper deposition and then to full-plate electroplating.

7. The method of claim 1, further comprising the steps of, between steps S4 and S5:

and S41, annealing the copper-clad plate with the manufactured outer layer circuit.

8. The method of claim 7, wherein in step S41, the temperature of the annealing process is controlled to 180 ± 5 ℃ for 2 hours.

9. The method of claim 1, wherein in step S1, the copper-free substrate is drilled before the annealing process.

10. The method of claim 1, wherein the copper-free substrate is an FR-4 board.

Technical Field

The invention relates to the technical field of printed circuit board manufacturing, in particular to a method for manufacturing a bottomless copper circuit board.

Background

With the increasing requirements of circuit boards for manufacturing fine circuits, particularly when laser drilling boards with line widths and pitches less than or equal to 2mil/2mil are used for manufacturing fine circuits, a bottomless copper manufacturing method is one of the key technologies for realizing the process, but the existing bottomless copper circuit board manufacturing method has the problem of poor bonding force between copper and a base material.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for manufacturing a bottomless copper circuit board, which improves the adhesive force of the surface of the bottomless copper circuit board and ensures that an electroplated copper layer is firmly combined with a base material by a physical and chemical roughening method.

In order to solve the technical problem, the invention provides a method for manufacturing a bottomless copper circuit board, which comprises the following steps of:

s1, cutting a copper-free substrate according to the size of the jointed board, and annealing the copper-free substrate;

s2, sequentially grinding, sand blasting and volcanic ash plate grinding treatment are carried out on the copper-free substrate;

s3, sequentially carrying out copper deposition and full-plate electroplating on the surface of the copper-free substrate to plate a copper layer to form a copper-clad plate;

s4, manufacturing an outer layer circuit on the copper-clad plate by adopting a negative film process or a positive film process;

and S5, sequentially manufacturing a solder mask layer on the copper-clad plate, and performing surface treatment and molding to obtain the circuit board.

Further, in step S1, the temperature during the annealing treatment was higher than the TG temperature of the copper-free substrate for 2 hours.

Further, in step S2, the copper-free substrate was polished with a 600-mesh abrasive belt.

Further, in step S2, the pressure for grinding, sand blasting and volcanic ash plate processing is 2.5 + -0.5 kg/cm²。

Further, the following steps are included between steps S2 and S3:

and S21, performing glue removing treatment on the copper-free substrate.

Further, in step S3, the copper-free substrate is first subjected to three times of copper deposition and then to full-plate electroplating.

Further, the following steps are included between steps S4 and S5:

and S41, annealing the copper-clad plate with the manufactured outer layer circuit.

Further, in step S41, the temperature during the annealing treatment is controlled to 180. + -. 5 ℃ for 2 hours.

Further, in step S1, before the annealing process, a hole is drilled in the copper-free substrate.

Further, the copper-free substrate is an FR-4 plate.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the copper-free substrate is annealed to eliminate the internal stress of the substrate and dry moisture, and then the surface of the substrate is fully roughened through a plurality of roughening procedures of grinding, sand blasting and volcanic ash grinding, so that the binding force between the substrate and the copper layer is enhanced, and the adhesion of the copper-free substrate is improved and the electroplated copper layer is firmly bound with the substrate by the physical and chemical roughening method; and annealing treatment is carried out again after the outer layer circuit is manufactured, so that the electroplated copper crystal lattice is improved, the internal stress matching degree of two different materials is improved, and moisture is removed. The binding force between the electroplated copper and the base material can be further increased; the invention adopts the method of directly electroplating copper on the copper-free substrate as the conducting layer, thereby realizing the thinning of the conducting layer and the manufacture of a refined circuit.

Detailed Description

In order to more fully understand the technical contents of the present invention, the technical solutions of the present invention will be further described and illustrated with reference to specific embodiments.