Specific Process Knowledge/Etch/Etching of Silicon Oxide/SiO2 etch using AOE

Danchip has recently (January 2009) taken over the AOE from Hymite. Not much process testing has been done yet.

Etching of micro structures in Silicon Oxide with photoresist or (poly)silicon as masking material

Parameter	Si mask	Resist mask
Coil Power [W]	1300	1000
Platen Power [W]	500	300
Platen temperature [oC]	60	0
He flow [sccm]	300	174
C$_{4}$F$_{8}$ flow [sccm]	18	10
H$_{2}$ flow [sccm]	0	8
Pressure [mTorr]	4	4

Typical results	Si mask non-confirmed result	Si mask DANCHIP result	Resist mask non-confirmed result	Resist mask DANCHIP result
Etch rate [nm/min]	500	460-480 (low aspect ratio)	300	280, 300
Selectivity [:1]	20	~15	4	3.2, 4
Profile [o]	>88	90.5-91.5 (negatively tapered)	>88	~88
Images	.	See here	.	See here

Etching of micro structures in Silicon Oxide with Aluminium as masking material

Parameter	Al mask
Coil Power [W]	1800
Platen Power [W]	180
Platen temperature [oC]	60
C$_{4}$F$_{8}$ flow [sccm]	80
O$_{2}$ flow [sccm]	10
Pressure [mTorr]	6

Typical results	Al mask non-confirmed result	Al mask DANCHIP result
Etch rate [nm/min]	>500	.
Selectivity [:1]	>50	.
Profile [o]	>88	.

Etching of sub-micro structures (trenches or holes) in Silicon Oxide with (poly)silicon or Aluminium as masking material

Parameter	Si mask	Al mask	Very thin Al mask
Coil Power [W]	1600	1100	2000
Platen Power [W]	200	500	140
Platen temperature [oC]	0	60	60
He flow [sccm]	300	50	60
C$_{4}$F$_{8}$ flow [sccm]	6	26	29
H$_{2}$ flow [sccm]	18	0	0
O$_{2}$ flow [sccm]	0	0	16
Pressure [mTorr]	4	8	3

Typical results	Si mask non-confirmed result	Si mask DANCHIP result	Al mask non-confirmed result	Al mask DANCHIP result	Thin Al mask non-confirmed result	Thin Al mask DANCHIP result
Etch rate [nm/min]	200	.	275	.	.	.
Selectivity [:1]	11	.	>50	.	Should be larger than for the other Al mask recipe	.
Profile [o]	86	.	90	.	90	.

Etching deep structures in quartz (micro size) with polySi as masking material (work in progress!!)

Parameter	Name of recipe:q_polysi
Masking material	PolySi
Coil Power [W]	1300
Platen Power [W]	500
Platen temperature [oC]	60
He flow [sccm]	300
C$_{4}$F$_{8}$ flow [sccm]	18
H$_{2}$ flow [sccm]	0
Pressure [mTorr]	4

Tested once	Si mask DANCHIP result
Etch rate [nm/min]	250 nm/min @etch depth of 50µm
Selectivity	~3µm of polySi was enough to get down to 50 µm
Profile [o]	Not known
Images	.