Atomic Removal
Energetic ion bombardment dislodges surface atoms from a substrate during vacuum deposition processing. Plasma cleaners or dry etching chambers produce this mechanical ejection phenomenon. Chemical sputtering yield quantifies the number of atoms removed from a solid target per incident reactive gas ion under specific plasma operating parameters.
Ion kinetic energy and angle of incidence dictate the baseline removal rate before reactive species alter surface bonding states. Target stoichiometry changes when volatile reaction products form faster than physical impact alone achieves.
Surface Degradation
Substrate damage occurs when reactive ions attack exposed features during anisotropic plasma etching steps. Overetching introduces microtrenches or redeposition anomalies across printed circuit board metallization layers. Engineers monitor chemical sputtering yield variations to prevent excessive undercut profiles beneath photoresist masks.
High desorption rates compromise sidewall passivation layers during deep reactive ion processing runs. Optical emission spectroscopy detects reaction byproduct fluctuations that signal shifts in etch selectivity ratios.
Process Control
Vacuum chamber pressure regulation stabilizes reactive radical densities near the substrate interface. Mass flow controllers adjust reactant gas mixtures to maintain reproducible removal rates across production batches. Post-etch scanning electron microscopy inspection measures remaining film thicknesses to verify acceptable material loss tolerances.
Process engineers calculate net etch depths by combining physical ion impact data with chemical reaction probabilities. Substrate temperature feedback loops prevent thermal runaway conditions that accelerate volatile byproduct formation.
