ATC-IM SERIES ION MILLING SYSTEMS
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AJA International ATC-IM Ion Milling Systems are versatile tools which are built in a variety of configurations depending on the specific requirement. Chambers can be either cylindrical or box style and either HV or UHV. SIMS endpoint detection is optional along with AJA's unique SIMS-IS isolation system which allows the SIMS head/detector to be kept under vacuum whenever the main chamber is vented. Systems can include computer control, load-lock, auto-loading, a multi-substrate cassette and mask exchange.
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AJA manufactures a wide variety of available substrate holders with features such as rotation, manual/motorized incident angle adjustment, heating, water cooling, LN2 cooling, backside gas cooling, and electrical isolation or biasing.
These systems can be configured for a broad range of applications ranging from nano pattern delineation to bulk wafer planarization. AJA manufactures or incorporates either gridless or gridded, RF or DC ion sources, with appropriate grid
materials and curvatures for the requirement. Systems have been manufactured to employ both inert and reactive/corrosive process gases with the appropriate safety gas box included on the equipment.
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TYPICAL ION MILLING SYSTEM CONFIGURATIONS
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ATC-2020-IM
Equipped with a 14cm, gridded, RF ion source positioned for uniform milling of a 100mm
Ø
substrate. System features a 700 l/s turbopump, computer control, SIMS end point detection, and substrate holder with motorized tilting, rotation, and water cooling.
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ATC-2020-IM (Internal view)
Features a 14cm, gridded, RF ion source with hollow cathode neutralizer, 6” substrate holder
with motorized/programmable +/- 90° tilt angle control, azimuthal rotation, water cooling, and SIMS end point detection.
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ATC-2036-IM
The system shown above is equipped with a RF 22cm gridded ion source positioned for uniform
milling of a 150mm
Ø
substrate. System features a 2000 l/s turbopump, computer control, SIMS end point detection, (2) sputtering sources for depositing passivation layers, and substrate
holder with motorized tilting, rotation, and water cooling. Etch rate is 320 Å/min of SiO
2
with +/-
2% uniformity.
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ATC-2036-IM with Motorized UNO Series Substrate Holder on Slide Mechanism
AJA UNO Series Substrate Holders feature simultaneous substrate rotation, water
cooling, and tilting to allow the ion beam incidence angle to be varied with precision.
The unit shown above has programmable, motorized tilting (+/- 90° ) and is mounted
on a retractable slide rail for easy access substrate load/unload and servicing.
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ATC-1800-IM-R
Utilizing a 14cm, gridded, RF ion source for uniform, reactive milling of a 100mm
Ø
substrate and features a 2000 l/s turbopump, computer control, retractable faraday cup,
load-lock with sputter gun for passivation layers, and a substrate holder with motorized tilting, heating/cooling (5-200°C). This tool is also compatible with Cl gas and includes a (4) MFC
hazardous gas box.
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ATC-1800-IM-R Hazardous Gas Box
The hazardous gas box (internal view left) is
suitable for reactive gases such as Cl and
includes MFC bypass lines, N
2
purging and evacuation, hazardous gas detectors and
double walled plumbing to the point of
processing. It is available for up to (4) gases
and mounts directly to the end of the
standard frame module.
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ATC 1800-IM-BSG ATC 1800-IM with BSG200 Substrate Holder - Schematic
The system shown above is equipped with a gridded ion source positioned for uniform milling of a 200mm Ø substrates. System features a 1200 l/s turbopump, load-lock with 6-position cassette, and substrate holder with backside gas cooling and rotation. Etch rate is 320 Å/min of
SiO
2
with +/- 2% uniformity.
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TYPICAL RATE / UNIFORMITY DATA
The angle of incidence to the substrate affects the rate and uniformity. One of the many benefits to the eccentric, off axis milling configuration is the reduced ion source size necessary to achieve uniform etching of larger wafers which would typically require costly, larger sources to achieve similar uniformity results. Angular incidence also improves removal rates while reducing damage to the substrate.
In addition to the milling angle, ion beam energies are a key component of milling rates. Depending on the ion source selected, ion energy can vary from 50-1200 eV allowing for a wide range of milling applications. For heavier milling requirements, higher ion energies are commonly desired. Lower ion energies are better suited for more sensitive substrates.
During the milling process, an increase of the substrate temperature can affect the milling rate and composition of material. Stabilizing the substrate temperature during the milling process is desired in order to maintain a consistent rate and uniformity and prevent substrate damage or unwanted modification.
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Typical milling profile yielding +/- 2% uniformity with SiO2 on a 6" Ø Si wafer and using an angled, gridded Kaufman style ion source. This process also utilized a BSG200 rotating wafer table equipped with helium gas backside cooling and programmable working distance adjustment.
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ION SOURCES
AJA manufactures and utilizes the leading ion sources on the market in all of the ATC-Series Ion Milling Systems. Systems are fitted with either DC/RF Kaufman style sources for high rate applications or capacitively/inductively coupled RF ion sources with grounded grids for sensitive, low energy applications. DC sources are typically employed for non-reactive milling (Ar only) and include exposed filament neutralization. RF ion sources are compatible with inert and reactive gases. Depending on the application, sources can be positioned in the chamber for direct or angular incidence to the substrate. Some of the available models include:
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The compact, cost effective, AJA designed and manufactured LEIS sources deliver moderate current density and are suitable for continuous Ar, O
2 and N
2 operation. These sources can be equipped with AJA's unique in-situ tilting feature which allows for source head angle adjustment without breaking vacuum. The capacitively coupled LEIS source is ideal for low energy milling applications (50-80 eV) and is capable of 10-15% dissociation of N
2 and O
2.
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CCR Copra ICP RF Ion Source
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The unique CCR COPRA Quasi-Neutral Plasma/Ion Source is a patented, capacitively/inductively coupled plasma/ion source able to deliver energies up to 200 eV at high currents. These sources are available from 75-400 mm grid Ø and feature an integrated RF matchbox. They are suitable for many reactive gases and are capable of 80-90% dissociation of N
2 and O
2.
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K & R Gridded RF and DC Ion Sorces and Neutralizers
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Both DC, filament style, and filamentless RF style, gridded ion sources with variable ion energies up to 1200 eV are available. DC ion sources are suitable for Ar and light O
2 service and are equipped with exposed filament neutralization. RF ion sources with protected plasma bridge neutralizers are utilized for reactive gases.
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