Claims
- 1. A system for controlling the image size of integrated circuits on a semiconductor wafer supported on a temperature-controllable hot plate; said system comprising:(a) means for positioning said wafer on a surface of said hot plate; (b) means for developing a predetermined temperature pattern across said wafer responsive to controlling the temperature across a plurality of zones extending over the surface of said hot plate; said zones being individually temperature-controllable for controlling the temperature ranging across the surface of said hot plate; (c) means for measuring the image linewidth of said integrated circuits at a plurality of locations across the surface of said wafer; (d) means for plotting and correlating the image line measurements with previously plotted image linewidth measurement data relative to past exposure bake temperatures to provide a standard; and (e) means for maximizing image linewidth uniformity by adjusting the temperature across the hot plate surface.
- 2. A system as claimed in claim 1, wherein a desired image linewidth size is subtracted from previously processed lots for each zonal image linewidth size data to form a matrix of image size deviations from a nominal size across the wafer for each surface zone.
- 3. A system as claimed in claim 2, wherein a temperature deviation changes (ΔT) are calculated from nominal temperatures required for each surface zone by dividing each element in the image size deviation matrix by a slope plotted from a temperature dependency graph relative to image size so as to determine a temperature correction for each said surface zone.
- 4. A system as claimed in claim 3, wherein there is retrieved a temperature set point versus zonal image linewidth size data for previously processed wafer lots, and substracting the temperature correction for each said zone so as to result in a matrix of zonal set points which are transmitted to a hot plate temperature controller for zonally adjusting the hot plate surface temperatures for current wafer processing.
- 5. A system as claimed in claim 1, wherein a temperature controller adjusts the hot plate temperature by modulating a power supply to heating coils arranged in zone across the surface of said hot plate.
Parent Case Info
This application is a divisional application of Ser. No. 09/314,368; filed on May 19, 1999.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5550007 |
Taylor et al. |
Aug 1996 |
A |
5656182 |
Marchman et al. |
Aug 1997 |
A |