A method for stripping a circuit board

Abstract

The application discloses a kind of line plate's stripping method, comprising the following steps: line plate is placed in the alkali solution containing stripping tank and soaked;Line plate is placed in the water tank and soaked;High-pressure water gun is used to flush line plate;Line plate after high-pressure water gun flushing is within 1h over development and washing, and development speed is controlled to 1m / min.The line plate stripping method provided by the application improves the quality of anti-welding stripping plate copper surface, improves product quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board manufacturing, and particularly relates to a method for removing solder resist of a printed circuit board. BACKGROUND

[0002] PCB (Printed Circuit Board) solder resist refers to covering a layer of solder resist ink on the surface of a PCB and / or exposed holes (which can be through holes or blind holes) to form a permanent protective layer for electrical environmental insulation and chemical corrosion resistance, so as to prevent the short circuit of wires caused by scratches and welding, and also to have the effects of moisture resistance, heat resistance, insulation and aesthetics.

[0003] With the development of printed circuit boards towards high density and high reliability, in the production process of printed circuit boards, the solder resist process is prone to cause problems such as poor hole plugging and other quality problems, and thus it is necessary to remove the solder resist ink from the PCB after solder resist. In the prior art, the printed circuit board after OSP will have a batch of copper surface color difference appearance problems. After analysis, the copper layer lattice of the removed printed circuit board is damaged, and the non-OSP solder resist removed board has a widespread fog-like defect. The copper surface fog-like foreign matter of the board mainly comes from the solder resist process. Such defects cause the components to easily fall off and be weakly welded during soldering of the printed circuit board, and thus cannot meet the quality requirements of customers.

[0004] In view of this, the present application aims to provide a method for removing solder resist of a printed circuit board to improve the quality of the copper surface of the board. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for removing solder resist of a printed circuit board, which can improve the quality of the copper surface of the solder resist removed board and improve the product quality.

[0006] The technical scheme of the present application is as follows:

[0007] A method for removing solder resist of a printed circuit board, comprising the following steps:

[0008] Step S1, soaking the printed circuit board in an alkali solution removal tank;

[0009] Step S2, soaking the printed circuit board in a clean water tank;

[0010] Step S3, using a high-pressure water gun to wash the printed circuit board;

[0011] Step S4, passing the printed circuit board washed by the high-pressure water gun through a developing tank within 1h, and the developing speed is controlled to be 1m / min.

[0012] Further, the number of single removal boards is controlled to be ≤60pnl.

[0013] Further, the plug-in plate is soaked in the stripping tank, and an ultrasonic cleaning process is performed.

[0014] Further, the mass concentration of the sodium hydroxide solution in the stripping tank is 10-15%, and the temperature is 80-90 DEG C.

[0015] Further, the soaking time of the circuit board in the stripping tank is 30-35 min, and the soaking time in the clean water tank is 15-20 min.

[0016] Compared with the prior art, the stripping method of the circuit board has the beneficial effects that:

[0017] The stripping method of the circuit board prevents the lattice of the copper surface from being damaged by residual chemical water on the board surface, and makes the copper surface of the board after development and rinsing normal without fog-shaped organic matter. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0019] Figure 1 is the board surface effect diagram after different residence time over development and rinsing in the stripping method of the circuit board of the present application. DETAILED DESCRIPTION

[0020] In order to make the person skilled in the art better understand the technical solutions in the embodiments of the present application, and make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the following will further describe the specific embodiments of the present application.

[0021] It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation of the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as there is no conflict.

[0022] A stripping method of a circuit board, comprising the following steps:

[0023] Step S1, placing the circuit board in a stripping tank containing lye for soaking;

[0024] The alkaline solution in the stripping tank is a sodium hydroxide solution with a mass concentration of 10-15% and a temperature of 85±5℃. When the circuit board does not require via plugging, it is directly immersed in the stripping tank for 30 minutes. When the circuit board is a via-plugged board, it is immersed in a stripping tank equipped with ultrasonic equipment for 35 minutes. The ink that has solidified in the holes is first soaked in sodium hydroxide solution in the stripping tank and softened under the action of ultrasonic vibration, making it easier to remove the ink in the holes.

[0025] Step S2: Soak the circuit board in a clean water tank for 20 minutes.

[0026] Step S3: Use a high-pressure water gun to rinse the circuit board in order to better remove the ink from the holes;

[0027] Step S4: After the circuit board is rinsed with high-pressure water gun, it is developed and rinsed within 1 hour, and the developing speed is controlled at 1m / min.

[0028] In this invention, the number of plates to be washed in a single wash is controlled to be ≤60pnl, which can improve the washing efficiency.

[0029] After cleaning, residual chemicals on the circuit board surface, if left for an extended period, can corrode the copper, damaging the copper lattice and affecting the board's appearance. Different processing times after high-pressure water jet rinsing result in varying copper surface quality on the circuit board. For example... Figure 1 As shown, after 3 hours of rinsing and development, the copper surface of the board becomes hazy. Figure 1 a) After 2 hours of rinsing and development, a slight haze appeared on the copper surface of the board. Figure 1 b); after rinsing and soaking for 1 hour, the copper surface of the board is normal, with no hazy organic matter. Figure 1 c).

[0030] The circuit board stripping method provided by this invention, after stripping, and then undergoing normal pre-solder resist treatment → silkscreen printing → pre-baking → exposure → development → text → post-baking, the copper surface under the solder resist layer is normal and without discoloration after OSP process, thus improving product quality.

[0031] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for stripping a circuit board, characterized by, The method comprises the following steps: S1, immerse the circuit board in a tank containing lye; S2, immerse the circuit board in a water tank; S3, use a high-pressure water gun to clean the circuit board; S4, pass the circuit board cleaned by the high-pressure water gun through a developing tank within 1 hour, and control the developing speed at 1 m / min.

2. The method of claim 1, wherein The number of single developing boards is controlled to be ≤60.

3. The method of claim 1, wherein the aqueous alkaline solution is an aqueous sodium carbonate solution. When the jack board is immersed in the developing tank, an ultrasonic cleaning process is implemented.

4. The method of claim 1, wherein the method is performed in a line. The mass concentration of the sodium hydroxide solution in the developing tank is 10-15%, and the temperature is 80-90℃.

5. The method according to claim 4, wherein The immersion time of the circuit board in the developing tank is 30-35 min, and the immersion time in the water tank is 15-20 min.

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