Claims
- 1. A process for forming a nitrogen rich layer of silicon nitride, comprising:admitting nitrogen, ammonia, and silane gases into a reaction chamber, at a pressure and in fixed relative concentrations; and initiating a plasma discharge within said gases thereby causing a layer of nitrogen rich silicon nitride to form, through plasma enhanced chemical vapor deposition, on a substrate.
- 2. The process of claim 1 wherein the step of admitting the gases in fixed relative concentrations further comprises adjusting and maintaining a flow rate for each gas.
- 3. The process of claim 2 wherein relative flow rates for nitrogen, ammonia, and silane of between about 4.5 and 6.6 to between about 4.5 and 6.6 to between about 0.9 and 1.1, respectively are maintained.
- 4. The process of claim 1 wherein the pressure is between about 10−3 and 10−1 torr.
- 5. The process of claim 1 wherein the plasma discharge is at a power level between about 90 and 120 watts.
- 6. The process of claim 1 wherein the substrate is at a temperature between about 250 and 300° C.
- 7. The process of claim 1 wherein the layer of nitrogen rich silicon nitride has a refractive index at 193 nm that is between about 2.29 and 2.31.
- 8. The process of claim 1 wherein the layer of nitrogen rich silicon nitride has an extinction coefficient at 193 nm that is between about 0.36 and 0.53.
- 9. The process of claim 1 wherein the nitrogen is admitted at a flow rate between about 45 and 66 SCCM, the ammonia is admitted at a flow rate between about 45 and 66 SCCM, and the silane is admitted at a flow rate between about 9 and 11 SCCM.
Parent Case Info
This is a division of patent application Ser. No. 09/097,145, filing date Jun. 12, 1998, now U.S. Pat. No. 6,045.954 Formation Of Silicon Nitride Film For A Phase Shift Mask At 193 Nm., assigned to the same assignee as the present invention.
US Referenced Citations (5)
Non-Patent Literature Citations (1)
Entry |
B.W. Smith et al. “The Effects of Excimer Laser Radiation on Attenuated Phase-shift Masking Materials” SPIE 1997. vol. 3051 p 236-244. |