Pt Etching - Platinum Etch

Plasma
Ion Beam

Pt >10 nm/ min (RIE"by Ar sputter etching)
Pt >50 nm/ min (ICP by Ar sputter etching)

Selectivity to PR mask ca 1 : 1 in RIE
Uniformity in RIE (12 wafer batch) < +/- 7 %
Uniformity in RIE or ICP
(single wafer 4"/ 6") < +/- 4 /5 %

For some (less demanding) applications a parallel plate reactor ("RIE”) is the preferred choice over an ion beam system because of its better throughput / cost.

120 nm Pt etch (and 400 nm PZT RIE),
PR mask intact.

An enhanced rate by reactive gases can
be achieved at elevated temperatures:
Ar/ Cl2 ICP etch

Pt Etch rate and selectivity over SiO2 mask

Platinum (Pt) Ion Beam Etching (IBE)

Process Specification

Pt IBE in the Ionfab300Plus (Large Chamber)
Process gas: Ar
Up to 200mm wafers
Summary performance data:

Chamber base pressurea	<4e-7 Torr
Load lock base pressureb	<2E-5 Torr


2 µm deep Pt Etch (PR Mask still in place)	Ionfab 300Plus

a. After 12 hours bake out at 80˚C
b. Load lock pumps down to 6E-5Torr in less than three minutes. It takes less than five minutes from sample loading i.e. from the load lock to process platen with load lock pump down sequence.

Notes:

Regular cleaning and conditioning of the chamber is required. This may occasionally involve a mechanical clean of the chamber.
Some variation in etch rate, selectivity and profile will be observed between wide features and narrow features.
Etch rate, profile, and selectivity data given above applies to wide features. Mask is PR unless otherwise stated
Profiles quoted require original mask profile to be >85°
Standard definitions of uniformity given below:

Within wafer uniformity is measured in a five point pattern:

Click for uniformity

Process specification

1. Pt etch with rotation and adjustable tilt.

Parameter/Process	Pt etch
Diameter etched	200 mm
Mask	PR
Gas chemistry	Ar
Typical etch rate [nm/min]	30nm/min
Uniformity [±%]3	<3
Reproducibility [±%]	<3
Selectivity to mask	>1