Manufacturing method for back drilling hole in PCB and PCB
A method for manufacturing a back drilling hole in a printed circuit board (PCB) and PCB are provided. The method for manufacturing the back drilling hole comprises: forming a through hole in the PCB ( 1 ); forming a metal layer ( 12 ) with prescribed thickness on an inner wall of the through hole; filling resin in the through hole which has been formed with the metal layer ( 12 ); performing back drilling machining on the through hole which has been filled with the resin; removing metal scraps remained in the through hole. The manufacturing method protects the hole wall copper by filling the hole with the resin, so that acid corrosion process only removes the remained metal scraps after back drilling of the small hole, does not affect on the hole copper of the resin protecting portion.
1. A method for fabricating back-drilled holes on a PCB, the method comprising:
forming through-holes on a PCB;
forming a metal layer with a preset thickness on inner walls of the through-holes;
filling resin in the through-holes in which the metal layer is formed;
back-drilling the through-holes filled with the resin; and
removing metal scraps remained in the through-holes.
2. The method for fabricating back-drilled holes on a PCB according to claim 1 , wherein the operation of forming the metal layer with the preset thickness on the inner walls of the through-holes comprises: forming the metal layer with the preset thickness on the inner walls of the through-holes in metal deposition and electro-plating processes.
3. The method for fabricating back-drilled holes on a PCB according to claim 1 , wherein the operation of filling the resin in the through-holes in which the metal layer is formed comprises: filling the resin in the through-holes in which the metal layer is formed using an aluminum sheet screen.
4. The method for fabricating back-drilled holes on a PCB according to claim 2 , wherein the preset thickness of the metal layer formed on the inner walls of the through-holes ranges from 13 micrometer to 104 micrometer.
5. The method for fabricating back-drilled holes on a PCB according to claim 4 , wherein the preset thickness of the metal layer formed on the inner walls of the through-holes ranges from 25 micrometer to 35 micrometer.
6. The method for fabricating back-drilled holes on a PCB according to claim 1 , wherein the operation of removing the metal scraps remained in the through-holes comprises: covering a dry film on an outer layer of the PCB, and etching the metal scraps remained in the back-drilled through-holes in an acidic etching process while forming a line pattern on the outer layer by transferring the pattern.
7. The method for fabricating back-drilled holes on a PCB according to claim 1 , wherein an aperture of the through-holes is 0.25 millimeter or more.