Step 9. Nitride etch

Step

Process

Date

Operator

9.1

Nitride etch in CENTURA-MXP

Chamber cleaning O2_CLEAN_MXP recipe (600s, 900W, 50scc O₂)

MXP_VAR_NIT with the following gas set up: Ar=50, CH₃F=20, O₂=7, 50mtorr, 450W

Non-uniform etch rate, nitride from center is removed much faster, bad selectivity to SiO₂

Endpoint noticeable, but long-drawn-out.

W#1-9 65s

W#10-15 62 s

For W#13 the following gas composition was used: Ar=50, CH₃F=50, O₂=7, 50mtorr, 450W

Even worse uniformity and etch rate in the middle is extremely slow, after this etch nitride cannot be removed even with the former recipe

06/01/07

Pongracz

9.2

Measure pad oxide thickness after etch on Nanoduv using the Thin oxide program:

	T	C	F	L	R
W#1	233	205	179	223	227
W#2	221	187	156	187	232
W#3	211	207	149	215	203
W#4	179	187	143	181	193
W#5	238	212	193	209	236
W#6	220	184	163	199	213
W#7	204	182	148	194	200
W#8	208	173	156	189	195
W#9	210	182	153	191	205
W#10	175	195	162	186	203
W#11	227	222	184	193	230
W#12	217	202	168	206	207
W#13	189	N/A	N/A	N/A	N/A
W#14	237	238	191	234	238
W#15	193	167	153	174	193

Note: W#13 had nitride on it after 60+3x65s+30s etching, the resist popped up, reworked, still some nitride in the middle

06/04/07

Pongracz