A HYPERVELOCITY SOURCE FOR SEMICONDUCTOR ETCHING

RESEARCHERS ARE DEVELOPING A HIGH FLUX, HIGH VELOCITY (3 TO 8 KM/S) CHLORINE ATOM BEAM FOR ETCHING SEMICONDUCTORS. CONVENTIONAL DRY ETCHING SYSTEMS ARE BASED ON ION-ASSISTED PROCESSES THAT CAN LEAD TO DEVICE DAMAGE AND DEGRADATION. NEUTRAL CHLORINE BEAM ETCHING SYSTEMS ARE UNDER DEVELOPMENT BUT ARE LIMITED TO LOW ENERGIES (>1 EV) OR HIGHER ENERGIES (>100 EV). LOW ENERGY SYSTEMS SHOW SIGNIFICANT UNDERCUTTING, AND HIGH ENERGY BEAMS CAUSE SUBSTRATE DAMAGE. RESEARCHERS ARE DEVELOPING AN ATOMIC CHLORINE BEAM TO OPERATE IN AN INTERMEDIATE ENERGY REGIME, 1 TO 10 EV. THE EFFORT IS BASED ON THE FAST ATOM SAMPLE TESTER (FAST) TECHNOLOGY. ATOMIC OXYGEN (1 TO 10 VE) PRODUCED USING FAST TECHNOLOGY EXHIBITS A STRONG CORRELATION BETWEEN ATOM ENERGY AND SURFACE REACTIVITY WITH GRAPHITE. THE DATA INDICATE AN INCREASE IN FIRST-COLLISION REACTION PROBABILITY, WITH BEAM VELOCITY, WHICH IS CRITICAL TO ACHIEVING HIGHLY ANISOTROPIC ETCHING. AT THE HIGHEST CL-ATOM BEAM ENERGIES AVAILABLE FROM THE FAST SOURCE, SUBSTRATE DAMAGE IS ENERGETICALLY UNFAVORABLE. THE RESEARCH DEMONSTRATES THE FEASIBILITY OF USING FAST CHLORINE BEAMS FOR SEMICONDUCTOR (SI AND GAAS) ETCHING BY MEASURING HIGH ETCHING RATES AND ANISOTROPY WITH A WELL-CHARACTERIZED CL-ATOM BEAM.