Specific Process Knowledge/Etch/AOE (Advanced Oxide Etch)/Quartz etch using AOE

Nanoetch in quartz 65mmx65mmx6.25mm substrates

by bge@danchip

Some priliminary results

The tests were done on 2" quartz wafers with a thickness of 1mm. These were placed on a 65mmx65mmx6,25mm quartz plate with a 2" groove. This 65mmx65mmx6,25mm plate was placed on a 4" Si wafer with a 65mmx65mm groove. the masking material was Cr sputter deposited in Wordentec and and patterned with ZEP520A resist by e-beam and ICP metal Cr etch.

Recipe used STS65x65:

Parameter	Crom mask
Coil Power [W]	1200
Platen Power [W]	500
Platen temperature [oC]	50
CF$_{4}$ flow [sccm]	43
C$_{4}$F$_{8}$ flow [sccm]	20
O$_{2}$ flow [sccm]	10
Pressure [mTorr]	8

Parameter	Results
Etch rate	~300nm/min
Etch profile	86-87 degrees
ARDE	There does not seem to be a significant aspect ratio dependency in the etch rate up to aspect ratio 1:2 ~ 1:3
Mask selectivity	20nm Cr is enough to etch 200nm in the quartz
Images	.

I am currently working on getting the right images in: 6. Jan 2012 /BGE

Process date: July 2011 Recipe: m_res_ny@0degrees Process time: 30 min Mask: AZ resist 4 µm thick The wafer wafer preheated to 150dg for 5min. Explation:The pretreatning makes the resist float and liquid evaporates. Then during the plasma processing there is no more liquid that evaporates and the surface do not contract during cool off. This gives more smooth edges between the wafer and the resist but the profile is more round giving more angled profiles of the oxide etch.

Process date: July 2011 Recipe: m_res_ny@0degrees Process time: 30 min Mask: AZ resist 4 µm thick The wafer wafer preheated to 150dg for 5min. Explation:The pretreatning makes the resist float and liquid evaporates. Then during the plasma processing there is no more liquid that evaporates and the surface do not contract during cool off. This gives more smooth edges between the wafer and the resist but the profile is more round giving more angled profiles of the oxide etch.