Health & Environmental Research Online (HERO)


Print Feedback Export to File
6590611 
Journal Article 
Plasma etching of molybdenum thin films in CF4, CCIF3, O2 and H2 gases 
Agrawal, N; Tarey, RD; Chopra, KL 
1992 
541-547 
INSPEC:4446293 
Thin films of molybdenum are among the prime candidates for gate metallization in VLSI circuits. The plasma etching studies sputter deposited molybdenum thin films have been carried out systematically in fluorocarbon (CF4), chlorofluorocarbon (CCIF3) and their mixture with oxygen (O2) and hydrogen (H2) gases using a low frequency (30 KHz) plasma diode reactor. Under the same conditions, the etch rate of molybdenum is 5-6 times higher in pure CF4 than it is in CCIF3. Addition of O2 to both CF4 and CCIF3 gases causes an enhancement in molybdenum etch rate and a maximum is observed at 50% and 80% of O2, respectively. However, hydrogen addition to both CF4 and CCIF3 inhibits molybdenum etching and generates carbon containing residues. Gas flow rate, power and partial pressure all influence the etching characteristics of molybdenum thin films. The etch rate and Auger electron spectroscopy results suggest that etch mechanism is controlled by both the plasma phase and plasma surface interactions. The partially etched molybdenum surfaces have been analyzed by scanning electron microscopy.