Traditional atmospheric pressure plasma cleaning techniques encounter limitations in photoresist removal from wafer surfaces
including limited area coverage and risk of sample damage. To address these challenges
this study innovatively introduces a microtubular array dielectric barrier discharge (DBD) plasma cleaning technology. This technique features a sophisticated design of interlaced high- and low-voltage microtubular dielectric tube electrodes
synergistically integrated with vertically injected high-speed gas jets. This unique configuration markedly expands the plasma’s footprint and drastically enhances the precision and efficiency of active particle delivery to the wafer surface
facilitating rapid
efficient
and non-invasive photoresist removal. The study investigates the impact of crucial parameters
including cleaning distance
cleaning time
discharge voltage
and gas flow rate
on photoresist removal efficiency
elucidating their underlying mechanisms. Advanced characterization tools
including water contact angle measurement
atomic force microscopy (AFM)
X-ray photoelectron spectroscopy (XPS)
and Fourier transform infrared spectroscopy (FTIR)
are employed to delve into the effects of plasma cleaning on wafer surface properties
encompassing hydrophilicity
roughness
elemental composition
and surface functional group transformations. Our experimental findings reveal that under optimized conditions (11 kV discharge voltage
0.5 mm cleaning distance
180 s cleaning duration
and 1 m/s gas flow rate)
a remarkable photoresist removal efficiency of 81.6% is achieved. Critically
this high level of cleaning performance is accomplished without compromising the wafer surface flatness or morphological integrity
indicating minimal to no discernible damage. Furthermore
both FTIR and XPS analyses confirm the effective elimination of photoresist residues and their associated chemical bonds to the wafer surface
while the introduction of polar functional groups
notably hydroxyls drastically enhances the wafer’s surface hydrophilicity (evidenced by a significant reduction in contact angle from 92.6° to 19.8°). This profound improvement in wettability establishes an optimal surface condition for subsequent deposition and doping processes
fostering uniform material distribution and efficient dopant penetration. Consequently
our research significantly contributes to the refinement of wafer manufacturing processes and the enhancement of device performance. Finally
the possible mechanisms underlying the removal of photoresist from the wafer surface during plasma cleaning are elucidated based on density functional theory (DFT) calculations.