Multi-chambered, compliant apparatus for restraining workpiece and applying variable pressure thereto during lapping to improve flatness characteristics of workpiece

A system for processing a workpiece having a length, a plurality of electrical contacts extending along the length, and a physical characteristic that varies along the length, the system comprising:

• a base having a plurality of ports extending therethrough and a plurality of flexible membranes, each of the ports being sealed on one end with a respective one of the flexible membranes to form an array, and each of the ports being independently pressurized for selectively expanding and retracting the flexible membranes;
• a flexible platform having an adhesive surface and mounted to the base such that the plurality of flexible membranes are covered by the flexible platform, and the flexible platform supports and restrains the workpiece with the adhesive surface in a direction tangential to the flexible platform so that the length of the workpiece is aligned with the array of flexible membranes, and pressure in the ports substantially restrains the workpiece from movement in a direction normal to the flexible platform;
• a probe cable having a set of electrical probes and movably mounted to the base between an engaged position for electrically engaging the electrical contacts with the electrical probes, and a disengaged position for electrically disengaging the electrical contacts with the electrical probes;
• a passive cable movably mounted to the base between an engaged position for physically engaging the workpiece opposite the electrical probes, and a disengaged position for disengaging the workpiece;
• a set of cantilever springs mounted to the base for selectively moving the probe cable and the passive cable between the engaged positions so that the workpiece is clamped between the probe cable and the passive cable, and the disengaged positions so that the workpiece is out of contact with the probe cable and the passive cable;
• and
• a controller for controlling the pressures in the ports, the probe cable, the passive cable, and the set of cantilever springs, such that the physical characteristic of the workpiece is ascertained by electrically to selectively adjust a pressure in each one of the ports and thereby manipulate and differentiate respective ones of the flexible membranes along the length of the workpiece to process the workpiece with respect to the physical characteristic.

A method of processing a workpiece, comprising:

• (a) mounting a workpiece to a fixture such that the workpiece aligns with an array of pressure ports located in the fixture, each of the pressure ports being sealed with a flexible membrane;
• (b) electrically interconnecting with the workpiece to measure a physical characteristic of the workpiece that varies along the workpiece;
• (c) selectively adjusting a pressure in each one of the pressure ports in response to step (b) and thereby expand and contract respective ones of the flexible membranes to accommodate the workpiece;
• (d) processing the workpiece with respect to the physical characteristic;
• and
• (e) repeating steps (b) through (d) until the physical characteristic of the workpiece is in compliance.