JP2003188494A - Method of preparing electrolytic corrosion test sample from defect generating base material of through hole section of printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preparing electrolytic corrosion test samples from which the declined insulation reliability of glass cloth which is in contact with the through hole of a printed board using a glass epoxy copper-plated laminated plate and the occurrence of copper migration in the glass cloth can be detected when hollow fibers occur in threads of the glass cloth. <P>SOLUTION: In this method, the electrolytic corrosion test sample from which the declined insulation reliability of the glass cloth and the occurrence of copper migration in the cloth can be detected when hollow fibers occur in threads of the glass cloth which is in contact with the plated through hole of the printed board using a glass epoxy copper-plated laminated plate are prepared during a swelling time of ≥6 minutes by using swelling liquid heated to ≥80°C in the de-smearing step of a printed board manufacturing process. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for producing an electrolytic corrosion test sample of a product having a defect in a through-hole base material. 2. Description of the Related Art In a printed board using a glass epoxy copper-clad laminate, if hollow fibers are found in a glass cloth thread used as a base material, an electrolytic corrosion test is performed to confirm reliability. Is carried out. Conventionally, test samples were drilled in copper-clad laminates, a common printed board manufacturing method,
A method of performing an electrolytic corrosion test using a desmear process, through-hole plating, and circuit processing has been adopted. In particular,
Regarding the swelling of desmear, treatment is performed with a desmear solution called a swerler or a swelling solution. The temperature of the swelling solution is generally 60 to 80 ° C., and the treatment time is generally 2 to 5 minutes. [0003] However, in an electrolytic corrosion test using a test sample prepared by the desmear process of a general printed board manufacturing method, a hollow of glass cloth in contact with through-hole plating is hollowed out. Even if fibers are generated, the swelling liquid temperature is low and the swelling time is short, and therefore, there is a problem that insulation reliability is lowered and copper migration cannot be detected due to low permeability of the solvent-based alkaline liquid. The present invention makes it possible to detect a decrease in insulation reliability and copper migration when a hollow fiber is generated in a thread of a glass cloth in contact with a through hole in a printed board using a glass epoxy copper-clad laminate. An object of the present invention is to provide a method for preparing an electrolytic corrosion test sample. [0004] The swelling of the desmear treatment of the present invention relates to the treatment conditions used for accelerating the desmear property before the desmear treatment, which is called a swerler or swelling liquid, is applied. . Specifically, the method is characterized by a method of preparing an electrolytic corrosion test sample in a case where hollow fibers are generated in a glass cloth thread of a base material in a through hole portion. The present inventors have conducted various experiments on a method of detecting migration of a printed board in which hollow fibers are generated in a glass cloth thread of a base material of a through-hole portion. By increasing the temperature of the
The present inventors have found that a decrease in insulation reliability and copper migration that cannot be normally detected can be detected, and have led to the present invention. [0005] The swelling of the desmear treatment of the present invention is as follows:
There is a processing step used to accelerate desmear property before processing into a desmear liquid generally called a swerler or swelling liquid. As the sweller or the swelling liquid, a solvent-based alkaline liquid is often used. For example, water 6
~ 80%, diethylene glycol monobutyl ether 2-
40%, caustic soda 2-10 kg / l, liquid temperature 80-90
The treatment is performed at a temperature of 6 ° C. for 6 to 30 minutes. This solvent-based alkaline liquid has a high permeability to cracks of resin or glass cloth yarns, but the liquid temperature is increased and the processing time is lengthened to ensure penetration. Then, dissolve with permanganate. [0006] Using a copper-clad laminate in which hollow fibers were confirmed as the yarn of the glass cloth, the swelling conditions of the desmear process after drilling were as follows: water 70%, diethylene glycol monobutyl ether 30%, caustic soda 5g / l, Liquid temperature 80
After processing at 15 ° C. for 15 minutes and dissolving with a permanganic acid solution and plating through holes, a circuit formed through hole between 0.5 mm and 1000 holes in an electrolytic corrosion test sample at 85 ° C. and 85% RH was used. When an electrolytic corrosion test was performed with DC 5 V applied, it was confirmed that the insulation resistance became 10 ⁵ Ω or less in 100 hours. In addition, as a result of polishing and observing the through-hole portion of the sample where the insulation was reduced from the surface, it was confirmed that copper migration occurred at the hollow fiber portion. In addition, the same electrolytic corrosion test was performed on the same copper-clad laminate, which was treated in the same desmearing step at a processing temperature of 70 ° C. and a processing time of 5 minutes.
Even after the time treatment, the insulation resistance was 10 ¹⁰ Ω or more, and no decrease in insulation reliability was confirmed. As described above, the electrolytic corrosion test sample prepared by increasing the swelling temperature in the desmear process of the present invention and lengthening the processing time is the same as the glass cloth thread in contact with the through hole. Since the permeability of the solvent-based alkaline liquid to the hollow fiber is improved, a decrease in insulation reliability can be surely confirmed.

Claims (1)

Claims: 1. In a printed board using a glass epoxy copper-clad laminate, if hollow fibers are generated in a glass cloth thread that is in contact with through-hole plating, the insulation reliability is reduced. A method for preparing an electrolytic corrosion test sample in which a swelling solution temperature is 80 ° C. or more and a swelling time is 6 minutes or more in a desmearing step of a printed board manufacturing process that enables detection of deterioration in properties and copper migration.