COB制程.pptVIP

Global Connections Inventec @ppliances Global Connections Inventec @ppliances Date : 08/30/2000 Prepared by Andy Gan COB Internal Training What is COB? COB Flow Chart 1 Clean COB 2 Drop Red Epoxy Resin 3 Mounting Chip 4 Bake 8 Encapsulate 7 Function Test 6 Process Test 5 Wire Bonding 9 Function Test 10 Bake 11 Function Test 12 Process Test COB Procedure 1.Clean PCB Clean spots which exists in PCB to assure dropping easily. COB Procedure 2.Drop Red Epoxy Resin Use in fixing chip, quantity of glue shall be exact and well mixed. COB Procedure 3.Mounting Chip Use vacuum pen to fix chip in PCB, notice polarity and shifting angle (5 degree). The air pressure is different from each chip. Vendor will adjust air pressure to the minimum at first, then raise it slowly to fit the requirement. 4.Bake Solidify epoxy resin by bake-box, fix chip. COB Procedure 5.Wire bonding Connect welding dot of chip and tin-foil in PCB by aluminum line. Effecting factor of wire bonding: a.Wire diameter b.Angle of welding c.Welding dot d.Tensile force of aluminum line Effecting factor of wire bonding a.Wire diameter Aluminum line has C.C.C, K.S and TANAKA, and diameter include 1.0 mil and 1.25 mil. Select 1.0 mil if distance of welding dot is little and thickness of PCB is big. Select 1.25 mil if distance between welding dot of chip and tin-foil in PCB, this also ought to fit the condition that the distance of welding dot is large and small thickness in PCB. Effecting factor of wire bonding b.Angle of welding must be less than 45 degree Corrective action if the angle is large than 45 degree 1.Rearrange the position of golden finger. 2.Prolong finger which be in “2”. Effecting factor of wire bonding c.Welding dot Minimum size of golden finger is 6 mil and minimum of distance is 6 mil too. Notice: The above welding dot minimum size is accuracy of FR4 glass fiber sheet. The requirement can’t be