Film stripping process of high-precision circuit board

Abstract

The invention relates to a film stripping process of a high-precision circuit board, and relates to the technical field of printed circuit board processing. The film stripping process of the high-precision circuit board sequentially comprises a bulking section, a film stripping section I and a film stripping section II, the bulking section adopts an inorganic film stripping solution with the mass concentration of 3-5% or an organic film stripping solution with the mass concentration of 10-12%, the film stripping section I adopts an environment-friendly high-precision circuit film stripping solution with the mass concentration of 10-12%, and the film stripping section II adopts an inorganic film stripping solution with the mass concentration of 3-5% or an organic film stripping solution with the mass concentration of 10-12%. According to the film stripping process, the film stripping speed is high, and the service life of the bath solution is long; film stripping is clean, no dry film residue is caused, and a copper surface and a tin surface are not corroded; the film removing device is suitable for film removing of fine lines, IC carrier plates and MSAP manufacturing procedures; and the film stripping liquid basically does not contain ammonia nitrogen and is very environment-friendly.

Description

technical field [0001] The invention relates to the technical field of printed circuit board processing, in particular to a film stripping process for high-precision circuit boards. Background technique [0002] In recent years, with the rapid development of electronic equipment, the lines have become more and more dense, and the line width and line spacing have become smaller and smaller. The line width / line spacing of mainstream products has developed from greater than 4mil / 4mil to less than 2mil / 2mil. The current mainstream HDI product line width / line spacing is about 2mil / 2mil, and the carrier board is about 1mil / 1mil. About 0.5mil / 0.5um. In the production process of high-precision circuits, the bonding force of the copper surface is relatively high, which leads to the increased difficulty of film stripping in circuit production, and is prone to problems such as unclean stripping, film sandwiching, and copper surface corrosion. [0003] At present, inorganic stripping ...

AI Technical Summary

Problems solved by technology

Inorganic system film removal solutions generally have quality problems such as low film removal rate, unclean film removal, and nozzle blockage due to excessive film damage; in addition, the attack of inorganic alkali on copper and tin surfaces will cause copper and tin surfaces to corrode, thus Quality problems such as copper surface color difference, line gap, line open circuit, etc.

[0004] Compared with the inorganic system stripping solution, the organic film stripping solution of monoethanolamine and tetramethylammonium hydroxide system has been proved to be a fast and clean product; / 2mil), IC carrier board, nickel-gold selective chemical dry film and MSAP process, the film removal time is longer, which is easy to cause copper surface corrosion and gold surface oxidation, and the film removal effect is poor.

At the same time, the ammonia nitrogen (brought in by ammonia water or ammonium salt) in the liquid medicine of this system will cause great trouble to the wastewater discharge after use by enterprises

In addition, tetramethylammonium hydroxide has poor stability and has a certain degree of toxicity, which limits its application range

[0005] The traditional film removal process can generally be divided into five steps: diffusion→swelling→rupture→cross-sectional attack→dry film detachment. The volume is narrow. This process causes the volume of the dry film to expand, and it is easy to cause the dry film to be sandwiched, resulting in the dry film not being able to detach smoothly.

In the process of removing the film, due to the long time, it will also cause corrosion of the copper surface or oxidation of the gold surface

Traditional inorganic film stripping solutions (about 3% sodium hydroxide or potassium hydroxide aqueous solution) and organic film stripping solutions based on monoethanolamine and tetramethylammonium hydroxide systems have reached their own limits and often cannot meet the requirements of new technologies. requirements

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