Fabrication process of stepped circuit board

Abstract

A fabrication process of a stepped circuit board comprises A) cutting a circuit board substrate, printing patterns on an inner layer of the circuit board substrate, stepped groove milling of the inner layer, washer milling a washer between the inner layer and an outer layer, brownification and lamination processing on the inner layer, and then drilling holes on an outer layer of the circuit board substrate; B) electroplating the entire circuit board substrate by depositing copper on the outer layer of the circuit board substrate with drilled holes; C) performing pattern transfer by means of through-hole plating of the drilled holes on the circuit board substrate processed by the copper depositing and the electroplating; D) after pattern transferring, grinding a shape of a connecting piece (SET) on the circuit board substrate after the electroplating; E) plugging the drilled holes to form plug holes and printing a solder mask and texts in a silk-screen manner after forming the plug holes; F) depositing nickel immersion gold on the entire circuit board substrate, then printing characters in a silk-screen manner, thereby forming the stepped circuit board; and G) testing and inspecting an electric performance and appearance of the stepped circuit board to fabricate a finished product of the stepped circuit board.