Technical description
Full equipment name: PlasmaTherm SLR ICP Etcher
General purpose:
• Deep reactive ion etching (DRIE) of silicon using Bosch process in right chamber
• Dry etching of aluminum and other metals in left chamber using chlorine-based chemistry
Technical data and restrictions:
• One loadlock system, one transfer chamber, and two ICP processing chambers (left and right)
• Standard wafer size: 100 mm (4"). Wafer clamping can be reconfigured for 150 mm (6") if needed.
• Wafer handling:
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Do not use glued wafer stacks. Non-flat surfaces may damage the clamp.
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Do not attach chips arbitrarily on a carrier wafer. Risk of movement can damage the clamp.
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Use approved carrier wafers with etched recesses and secure mounting for chip-level processing (only after training and approval).
• Right chamber:
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ICP chamber configured for DRIE of silicon
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Primarily used for high-aspect ratio etching using the Bosch process
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Typical etch rate: ~1 µm/min (varies by feature size and open area)
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Selectivity (approx.):
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Process gases: SF6, C4F8, He, O2
• Left chamber:
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ICP chamber configured for metal etching
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Standard use: aluminum etching with chlorine-based chemistry
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Other metals or compounds may be etched only after consultation with MSL
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Process gases: Cl2, BCl3, O2, Ar
Description before 2025-04-14
PlasmaTherm SLR
The PlasmaTherm SLR has 2 ICP processing chambers plus a transfer chamber and a load-lock.
The tool will normally be set up for 100 mm (4") wafers. However, it is quite easy to change the wafer clamping to 150 mm (6").
It is not allowed to etch two wafers glued together! It will not be flat enough and will cause the clamp to break.
It is not allowed to arbitrary and ad hoc glue smaller pieces onto a wafer. There is a risk that chips move to the edge and break the clamp. After instruction and training, specially made carrier wafers with etched recess are to be used and the chips have to be securly fastened in the recesses.
The right chamber is used for Deep Reactive Ion Etching (DRIE). It is primarily intended for etching deep features in silicon by means of the Bosch process.
The etch rate will depend strongly on the feature size and the amount of exposed area. A typical value is an etch rate of around 1 µm/min.
Typical selectivities for silicon etching are 80 for photo resist and 200 for silicon oxide. An aluminum mask has a very high selectivity and may be used for etching through a wafer.
The left chamber is intended for metal etching using chlorine chemistry. It is mainly used for aluminum etching.
Other metals and metal compounds may be etched in the left chamber after discussions with MSL.