▁and ▁a ▁co pper ▁ball ▁had ▁proven ▁to ▁work ▁well . ▁Therefore , ▁the ▁ball ▁was ▁simply ▁removed ▁and ▁the ▁sol der ▁ev ap oration ▁process ▁extended ▁to ▁form ▁pure ▁sol der ▁b umps ▁that ▁were ▁approximately ▁ 1 2 5 μ m ▁high . ▁This ▁system ▁became ▁known ▁as ▁the ▁controlled ▁collapse ▁chip ▁connection ▁( C 3 ▁or ▁C 4 ). ▁ ▁Until ▁the ▁mid - 1 9 9 0 s , ▁this ▁type ▁of ▁f lip - ch ip ▁assembly ▁was ▁pract iced ▁almost ▁exclus ively ▁by ▁IBM ▁and ▁Del co . ▁ ▁Ar ound ▁this ▁time , ▁Del co ▁sought ▁to ▁commercial ize ▁its ▁technology ▁and ▁formed ▁F lip ▁Ch ip ▁Techn ologies ▁with ▁K ul ic ke ▁& ▁So ff a ▁Indust ries ▁as ▁a ▁partner . ▁ ▁At ▁the ▁same ▁time , ▁M CN C ▁( which ▁had ▁developed ▁a ▁pl ated ▁version ▁of ▁IBM ’ s ▁C 4 ▁process ) ▁received ▁fund ing ▁from ▁D AR PA ▁to ▁commercial ize ▁its ▁technology . ▁These ▁two ▁organizations , ▁along ▁with ▁A PT OS ▁( Ad vanced ▁Pl ating ▁Techn ologies ▁on ▁Sil icon ), ▁formed ▁the ▁nas cent ▁out - s our cing ▁market . ▁ ▁During ▁this ▁same ▁time , ▁companies ▁began ▁to ▁look ▁at ▁reducing ▁or ▁stream lin ing ▁their ▁pack aging , ▁from ▁the ▁earlier ▁multi - ch ip - on - cer am ic ▁packages ▁that ▁IBM ▁had ▁originally ▁developed ▁C 4 ▁to ▁support , ▁to ▁what ▁were ▁referred ▁to ▁as ▁Ch ip ▁Sc