Flip Chip Technology: A Method for Providing Known Good Die with High Density Interconnections

Flip chip interconnections provide the highest interconnection density possible which makes this technology very attractive for use with multichip modules. However, several factors have hindered the use of this technology. These factors include the availability of bumped wafers and the inability to test and bum-in bumped chips before they are assembled onto a multichip module. MCNC has addressed both of these concerns by establishing a wafer bumping facility and by developing a method for the test and burn-in of bare die. The solder bump formation is based upon an electroplating process. The test and burn-in of bumped chips is accomplished using a unique process which utilizes a temporary metallurgical attachment to a test substrate. These processes are described in detail in the following sections.