Polysilicon plasma etch (anisotropic, MOS clean): View

Process Hierarchy

on front

Polysilicon plasma etch (anisotropic, MOS clean)

Process characteristics:

Depth

Depth of material removed by etch process

0.01 .. 1 µm

Ambient

Ambient to which substrate is exposed during processing

carbon tetrafluoride, HBr, chlorine, helium, oxygen

Aspect ratio

Batch size

Etch rate

0.3 µm/min

Material

polysilicon

Min feature size

1 µm

Pressure

Pressure of process chamber during processing

100 mTorr

Selectivity

Primary material removal rate divided by removal rates of secondary materials (i.e., factors by which primary material is removed faster than secondary materials)

photoresist (category): 10, polysilicon: 1, silicon dioxide: 10

Sides processed

either

Temperature

60 °C

Wafer size

Equipment

Applied Materials Precision 5000 (chamber C)

Equipment characteristics:

Wafer holder

Device that holds the wafers during processing.

mechanical clamp

Wafer materials

List of wafer materials this tool can accept (not list of all materials, just the wafer itself).

silicon, quartz (single crystal), silicon on insulator, silicon germanium

Wafer thickness

List or range of wafer thicknesses the tool can accept

350 .. 750 µm

Comments:

This is an MOS clean machine.
Amorphous silicon and
silicon can be etched as
well.
Resist must be baked at 110
degC at least 24 hrs before
etching.
No resist allowed on
backside of wafers.
Resists thicker that 1.6 um
will burn. Users should
consider an alternate
masking material.
Quartz wafers must have
non-transparent material on
backside.
The outer 5 mm of the edge
of the wafers must be free
of resist to avoid wafers
sticking the the chuck clamp.
Endpoint detection
available, assuming etch
stop material is oxide.