A series of experiments was run to determine the chemical and
process effects on CD uniformity for Dynachem's new dyed
photoresist, NOVA 2050 AR, when developed with metal ion free and
metal ion type developers. The matrix of experiments included
variations in spray time and puddle time, but with the constraint
that all experiments had the same total time for spray and puddle
times. In order to do this type of matrix it was necessary to make
an unusual use of a mixture model to devise the experimental
The design was devised to look at the effects of one-puddle, twopuddle,
three-puddle and all-spray processes. Also, the effect of
using either metal ion free or metal type developers was examined
by running the matrix with Dynalith EPD-85 and DE-3 (0.5%) as
respective examples of the two developer types.
Before beginning the above matrix the baseline parameters for
nozzle position, puddle time, spray time, spray speed, pre-wet
time, spray pressure and spray time were determined via a Plackett-
Burinan design of experiments.
These three studies when compiled and analyzed with the statistical
software package, RS-l, served to separate the effects of process
parameters and developer type according to their effect on CD
uniformity. These results suggest that three-puddle metal ion free
develop processes were superior.
Graphs will be shown that illustrate which parameters are the most
influential concerning CD uniformity. A mathematical model will be
presented that will allow the calculation of the standard deviation
for CD uniformity with 95% confidence for any given set of spray
and puddle times.
These data and models will thereby give guidance to the process
engineer how to best use developer type and process in order to
obtain the best CD uniformity for a 1.0 micron process.