CPC H05K 3/282 (2013.01) [H05K 3/0091 (2013.01); H05K 3/103 (2013.01)] | 3 Claims |
1. A circuit board comprising:
a circuit substrate comprising a base layer and an outer wiring layer formed on the base layer, and a via hole connected to the outer wiring layer;
a first protective layer made of white oil and formed on the outer wiring layer and an inner sidewall of the via hole;
a mark made of white oil and formed on the outer wiring layer by a silk-screen printing process, the silk-screen printing process further configured to form the first protective layer when printing the mark; and
a second protective layer made of a three proofing paint, the second protective layer formed on the first protective layer which is on the outer wiring layer, the second protective layer further formed on the first protective layer which is on the inner sidewall of the via hole.
|