JPS5925979A - Surface cleaning method of copper clad laminated sheet - Google Patents

Abstract

PURPOSE:To eliminate the possibility arising problems such as in the case of polishing and to clean the surface of a copper clad laminated sheet, by oxidizing the surface of said sheet then dipping the same in an acid soln. CONSTITUTION:A copper clad laminated sheet is first dipped in a copper oxide treating soln. A copper acetate soln. or the like is usable for the treating soln. and while the soln. is kept heated to about 60-80 deg.C, the sheet is dipped therein for about 3min. Then, an extremely thin copper oxide film is formed on the surface of the laminated sheet. The laminated sheet is thereafter dipped in an acid soln. Hydrochloric acid, etc. are usable as the acid soln., and the use of about 5-10% soln. of ammonium persulfate is more preferable in terms of beautiful finish. The copper oxide film formed on the surface of the copper foil is dissolved away by such dipping in the acid soln., and the rust preventive, org. material, etc. stuck on the surface of the copper foil are removed together with the copper oxide film in this stage, whereby the surface of the laminated sheet is cleaned.

Description

[Detailed Description of the Invention] The present invention relates to a method for cleaning the surface of a copper-clad laminate used for printed wiring boards, in which the copper-clad laminate is immersed in a copper acetate solution or the like to oxidize the copper surface, and then the copper surface is oxidized. The present invention relates to a method for cleaning the surface of a copper-clad laminate, characterized by dissolving copper oxide in the acid solution by immersing the copper clad laminate in the acid solution.

The copper surface of copper-clad laminates often has rust preventives attached, organic matter such as hand marks, or oxides attached, and printed wiring boards are used to remove these. There are many steps to clean the copper foil surface in the manufacturing process, namely (1) pre-treatment for printing of etching resist ink and sticking resist ink, (...) coniting of photoresist and photosensitivity 1' These cleaning treatments include pretreatment for laminating IJ life film, (■) pretreatment for printing solder resist ink, and (■) pretreatment before lamination molding of multilayer printed wiring boards.

Conventionally, in such a cleaning process, the surface of the copper foil was cleaned by polishing the copper surface using a polishing machine.1. In such mechanical polishing, there is a risk that the thin copper will be caught in the polishing machine's roll and be peeled off or damaged, and there is also a risk that the copper foil will be stretched and the positional accuracy of the circuit will be disrupted.1. Furthermore, uniform cleaning is difficult and there is a risk that cleaning may become insufficient. In addition, the thin copper-clad laminate 1 had many variations and was impossible to clean. If the cleaning is insufficient in this way, in the case of (I) and (II) above, the resist ink may not adhere to the steel vessel or may peel off during the etching or plating process, preventing normal circuitry. In the case of (m), the resist or film may not be tightly attached to the copper foil.
is insufficient to withstand the soldering process/J
In the case of (1v), there arises a problem that the adhesion between the inner layer circuit copper foil and the adhesive prepreg is insufficient, which may cause poor adhesion or heat resistance of each layer.

The present invention solves the above-mentioned drawbacks, and aims to provide a method for cleaning the surface of a copper-clad laminate that can be cleaned without causing problems such as those caused by polishing. It is something.

The present invention will be explained in detail below with reference to Examples.

Copper-clad laminates are made by layering multiple sheets of prepreg obtained by impregnating and drying a thermosetting resin such as phenol resin, epoxy resin, unsaturated polyester resin, polyimide, polyamide, or polybutadiene into a base material such as paper or glass cloth, and then It is obtained by stacking copper foils and forming them under heat and pressure.When cleaning the copper foil surface of such copper-clad laminates,
First, a copper-clad laminate is immersed in a copper oxide geoliquid. A copper acetate solution or the like can be used as the copper oxide treatment solution, and the substrate is immersed in this treatment solution heated to 60 to 80° C. for about 3 minutes. When treated in this manner, an extremely thin copper oxide film is formed on the surface of the copper-clad laminate.

Next, the copper-clad laminate thus treated is immersed in an acid solution. As the acid solution, a hydrochloric acid solution, a sulfuric acid solution, an ammonium persulfate solution, etc. can be used, but it is preferable to use a 5 to 10% aqueous solution of ammonium persulfate in terms of the beautiful finish. By immersing the copper 7 in the acid solution, the copper oxide film formed on the surface of the copper 7 is dissolved and removed, and when the copper oxide film is removed, the rust preventive and organic substances deposited on the copper clad surface are removed. , oxides, etc. are removed together with the copper oxide coating, and the surface of the copper-clad laminate is cleaned.

As described above, the present invention oxidizes the surface of the copper-clad laminate and then immerses it in an acid solution to dissolve the copper oxide in the acid solution, so there is no need to perform mechanical polishing using a polishing machine. Matsushita Electric Works, patent applicant Representative Patent Attorney Co., Ltd. Toshimaru Takemoto (and 2 others)

Claims (2)

[Claims] (1) A method for cleaning the surface of a copper-clad laminate, which comprises oxidizing the surface of the copper-clad laminate and then immersing it in an acid solution to dissolve the copper oxide in the acid solution. (2) #The method for cleaning the surface of a copper-clad laminate according to claim 1, wherein the solution is an ammonium persulfate solution.