Method for Functional Testing of High Speed VLSI Devices and Cache Systems
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
This article describes solutions to two major technical problems present in high-speed VLSI functional testing. The space transformer presents the first major problem for high speed functional testing. The space transformer consists of the electrical connection between the test pin head at one end and buckling beam probe tip that contacts the chip under test at the other end. The cobra connector has a self-inductance of about 700 picohenries and pairwise mutual inductance of about 200 picohenries (with signal-to- ground ratio of 6 to 1). This inductive discontinuity limits the test speed to 250 MHz or below. As pointed out above, to monitor the VLSI chip outputs without an electrical space transformer is the key to building gigahertz testers.