Patent ID: 6507942
Filing Date: 2003-01-14
Classification: H01L

Abstract:
A method for measuring feature-size uniformity across a surface of a programmable logic device, wherein the programmable logic device is configurable using a collection of configurable elements to provide specified logic functions, the method comprising:a. configuring a first set of the configurable elements in a first region of the programmable logic device to include a first oscillator, wherein the first oscillator oscillates at a first frequency that depends upon a first device having a first critical dimension; b. configuring a second set of the configurable elements in a second region of the programmable logic device to include a second oscillator, wherein the second oscillator oscillates at a second frequency that depends upon a second device having a second critical dimension; c. measuring a difference between the first and second frequencies to obtain a frequency difference; and d. correlating the frequency difference to an extent of feature-size uniformity, the greater the frequency difference, the less the feature-size uniformity.