Specific Process Knowledge/Etch/RIE (Reactive Ion Etch)

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Etching using the dry etch technique RIE (Reactive Ion Etch)

File:Cluster1.jpg

RIE1 (part of Cluster1) - positioned in cleanroom2

File:Cluster2.jpg

RIE2 (part of Cluster2)- positioned in cleanroom3

At Danchip we have three RIE's. Two (RIE1 and RIE2) for etching silicon based materials, resist and polymers (mainly RIE2) and one (III-V RIE) for etching III-V materials. Here only RIE1 and RIE2 will be described.

The hardware of RIE1 and RIE2 is very similar, but you cannot count on that identical recipes on RIE1 and RIE2 perform exactly the same. In addition to that the main difference between RIE1 and RIE2 is the cleanness of the two equipment. In rough terms RIE1 is the clean system and the RIE2 is the dirty system. This means that in RIE2 opposed to RIE1 it is allowed to have small amounts of metals exposed to the plasma.

The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager:

RIE1 info page in LabManager,

RIE2 info page in LabManager

Process information

• Etch of silicon using RIE
• Etch of silicon oxide using RIE
• Etch of silicon nitride using RIE
• Etch of photo resist using RIE

Equipment performance and process related parameters

Equipment		RIE1	RIE2
Purpose	Dry etch of	Silicon Silicon oxide Silicon (oxy)nitride Resist	Silicon Silicon oxide Silicon (oxy)nitride Resist and other polymers
Performance	Etch rates	Silicon: ~0.04-0.8 µm/min Silicon oxide: ~0.02-0.15 µm/min Silicon (oxy)nitride: ~0.02-? µm/min	Silicon: ~0.04-0.8 µm/min Silicon oxide: ~0.02-0.15 µm/min Silicon (oxy)nitride: ~0.02-? µm/min
	Anisotropy	Can vary from isotropic to anisotropic with vertical sidewalls and on to a physical etch where the sidewalls are angled but without etching under the mask.	Can vary from isotropic to anisotropic with vertical sidewalls and on to a physical etch where the sidewalls are angled but without etching under the mask.
Process parameter range	Max pressure	800 mTorr	949 mTorr
	Max R.F. power	600 W	600 W
	Gas flows	SF6: 0-52 sccm O2: 0-99 sccm CHF3: 0-100 sccm CF4: 0-42 sccm Ar: 0-146 sccm N2: 0-100 sccm C2F6: 0-24 sccm	SF6: 0-130 sccm O2: 0-99 sccm CHF3: 0-99 sccm CF4: 0-84 sccm Ar: 0-145 sccm N2: 0-99 sccm
Substrates	Batch size	1 4" wafer 1 2" wafer (use Al carrier with Si dummy wafer) Several smaller samples (use Al carrier with Si dummy wafer)	1 4" wafer (use Al carrier with Si dummy wafer) 1 2" wafer (use Al carrier with Si dummy wafer) 1 6" wafer (requires 6" setup) Several smaller samples (use Al carrier with Si dummy wafer)
	Allowed materials	Silicon Silicon oxide (with boron, phosphorous and germanium) Silicon nitrides (with boron, phosphorous and germanium) Pure quartz, fused silica (not Pyrex, Tempax and other glasses) Resists: AZ resists, e-beam resists, SU8, DUV resists Aluminium as thin film layer on your sample	Silicon Silicon oxide (with boron, phosphorous and germanium) Silicon nitrides (with boron, phosphorous and germanium) Pure quartz, fused silica (not Pyrex, Tempax and other glasses) Resists: AZ resists, e-beam resists, SU8, DUV resists Other olymers (ask the Plasma group for permission) Aluminium as thin film layer on your sample Other metals (<5% coverage of the wafer)