Sequential Monomer Film Deposition for Precise CD Pattern Transfer

The patent applies periodic action by alternately supplying first and second monomers in repeated cycles. Each cycle consists of supplying the first monomer, then the second monomer, creating a periodic deposition pattern that builds the polymer film layer by layer. This periodic supply method prevents surface roughness by ensuring uniform distribution and controlled reaction rates, ultimately achieving smooth surfaces and high pattern precision.

The patent segments the monomer supply process into distinct stages: first monomer supply, second monomer supply, and purge gas supply. By dividing the film formation into these separate segments rather than continuous supply, the process allows for controlled reaction progression and prevents localized accumulation that would cause surface irregularities, thereby improving both surface smoothness and pattern accuracy.

The periodic alternation between first and second monomer supply enables both high productivity and precise thickness control. By repeating the cycle multiple times with optimized durations, the film builds up quickly (high productivity) while each cycle contributes a controlled, uniform layer (precise thickness control). The periodic nature ensures that neither monomer accumulates excessively, maintaining reaction control throughout the formation process.

The patent employs preliminary action by supplying the first monomer before the second monomer in each cycle. This sequential arrangement allows the first monomer to establish a foundation layer that controls subsequent reaction rates, preventing runaway polymerization and enabling precise thickness control. The preliminary supply of the first monomer sets the stage for controlled film growth while maintaining high overall formation speed.

The periodic supply of first and second monomers creates uniform polymer film growth that accurately replicates the resist pattern. Each cycle contributes evenly distributed material that smooths surface irregularities while preserving pattern fidelity. This periodic deposition ensures that critical dimensions are maintained throughout the film thickness, enabling accurate pattern transfer without distortion from surface roughness.

The patent utilizes parameter changes by controlling the supply rates, pressures, and timing of monomer introduction during the periodic cycles. By adjusting these parameters across different cycles, the process optimizes both surface smoothness and pattern accuracy simultaneously. The dynamic control of supply parameters ensures uniform film formation that faithfully transfers the resist pattern while eliminating surface irregularities that would compromise critical dimension control.