P5000 RIE/Processes/OXIDE BKM
|Warning:||This page has not been released yet.|
|About this Process|
|Mask Materials||PR, Polysilicon|
|Gases Used||Ar, CHF3, CF4|
|Authored By||AMAT, Kevin Owen|
The OXIDE BKM recipe is a general recipe for etching silicon dioxide films on the P5000 RIE/Processes. It has a fast etch rate (3800 Å/min) and reasonable selectivity to photoresist and polysilicon, but low selectivity to silicon nitride. This recipe can be run in chambers A or B depending on the sample's material requirements.
- Review the material restrictions for each chamber and choose the appropriate one for the application.
- Follow the procedure outlined in the SOP.
- Open the
OXIDE BKMProcess Program.
- Edit the time in either
ETCH A Onlyor
ETCH B Onlydepending on the chamber used.
- Select either
OXIDE A BKMor
OXIDE B BKMfrom Wafer Lot Names.
Bulk etch rates for various oxides, nitrides, and masking materials are shown below. High aspect ratio (narrow) trenches will etch slower.
|Thermal oxide||3800 Å/min|
|PECVD oxide||1300 Å/min|
|Low stress nitride||1300 Å/min|
|SPR 220||1500 Å/min|
- Within-wafer uniformity: <4% (3 mm edge exclusion)
- Etch rate is faster at the edge
- Wafer-to-wafer uniformity: <2%
Mask selectivity of Thermal oxide to a selection of materials is shown below. Selectivity for your material can be calculated using the etch rates listed above.
|Low stress nitride||2.92:1|
- 78 degrees - low aspect ratio features
- 87 degress - high aspect ratio, submicron features
|Power||0 W||750 W|
|Magnetic field||40 G||40 G|
|Pressure||250 mTorr||250 mTorr|
|Argon Flow||75 sccm||75 sccm|
|CHF3 Flow||25 sccm||25 sccm|
|CF4 Flow||5 sccm||5 sccm|
Etch rate is very linear, tested down to 5 seconds. Maximum etch time is mask dependent, have demonstrated up to 4 µm etch depth.
This etch is not significantly load dependent.
This etch deposits fluorocarbon as its primary selectivity mechanism. Thickness of fluorocarbon on sidewalls increases as feature size increases and may be as thick as 100nm. A post etch ash in the YES Plasma Stripper using Recipe 2 is highly recommended.
The bulk etch rate of thermal oxide is verified occasionally by running the recipe for 2 minutes.