Micro-Probe Incorporated v. Wentworth Laboratories, Inc.

Wentworth Laboratories, Inc. (“Went-worth”) appeals from summary judgment in favor of Micro-Probe Incorporated (“Micro-Probe”). The district court held that Micro-Probe’s device for testing integrated circuits did not infringe Wentworth’s patent. The district court granted summary judgment on the ground that Micro-Probe does not manufacture a device that Claim 1 of Wentworth’s patent encompassed, invoking the file-wrapper estoppel doctrine. The district court expressly denied the challenge to the validity of the Wentworth patent, correctly deciding that material issues of fact foreclose summary judgment on that ground. We reverse because we believe that triable issues of fact also foreclose application of the file-wrapper estoppel doctrine.

I

Wentworth is the assignee of a patent for a fixed-point probe card (“Wentworth patent”). A probe card is a small, flat, rectangular device that has a circular opening in its center into which metal needles extend. These needles are attached to evenly spaced pads, and conductive paths lead from the pads to terminals at the edge of the card that can be connected to external testing equipment. When a probe card is applied to an…