This excerpt taken from the VRGY 10-K filed Dec 22, 2006.
Production Prototype. Once an initial design of a semiconductor has been created, the first stage in bringing an actual IC to market is to produce a small quantity of prototype ICs to validate the design and ensure that it performs according to its specifications. What the semiconductor designer needs most from the test equipment and services provider at this stage is advanced test equipment and test strategy expertise. The engineering validation and device characterization that occurs at this stage requires high precision test equipment to ensure accuracy and high flexibility to modify test procedures and parameters, because the IC design may iterate multiple times. Test strategies and methodologies are developed early to ensure that the test solution implemented is capable of testing the ICs across the entire manufacturing process. Of all the stages of bringing a new semiconductor to market, it is at this stage that the most advanced test equipment is required.