There are two important test processes in the semiconductor production process.
One is a wafer test process in which characteristics of each of many semiconductors (called die or chip) formed on a wafer are tested before the chips are diced, and the other is a final test process performed after a diced chip has been packaged. While a probe card explained in Section 1 in this Technological Column is used in the former process, a test socket is used in the latter process and functions in a similar manner to how a probe card functions in the former process. Like a probe card, a test socket plays an important role in connecting a device to a tester. (Refer to the figure below.)
Two kinds of sockets are used in the final test process.
One is a burn-in socket for a reliability test mainly checking endurance of a package, and the other is a test socket for an electric characteristic test. In general, these are collectively called an IC socket, but each of them needs to have different performance from that of the other in accordance with its different application. Our package probe, J-contacts is a high-efficient socket, having more excellent electric characteristics and in particular high-frequency characteristics than those in a conventional test socket and testing an LSI for mobile communication and electronic equipment. * We call our test socket "package probe" to differentiate it from other test sockets as ours can probe an LSI package in a higher test range than that in conventional test sockets.