Microprobing on Sub-Micron Features on ICs Using an AFM Based Technique

Abstract

Traditional microprobing on conventional wirebonded packages is difficult on sub-micron feature sizes. The problem becomes even more complex with flip-chip packaged devices as access to circuitry is limited because of the substrate silicon. We describe here an Atomic Force Microscope (AFM) based tool for microprobing that we term “nanoprobing” because of the feature sizes that can be probed with this tool. Three applications have been described here where voltage levels or waveforms are measured. These include probing on: A single metal-layer test chip that is wire-bonded to a 40-pin DIP package, a 3-layer CMOS circuit that is wire bonded to a 48 pin DIP package, and a 5-metal layer CMOS circuit that is flip chip packaged to a 321 pin PGA package.