GENERAL INFORMATION

The AJA International, Inc. ATC Ion Milling Systems are versatile tools that can be built in a wide variety of configurations. Depending on your application, these custom designed systems utilize state of the art substrate holders and ion sources. Chamber sizes vary from 10"-22" in diameter and can also include computer control, load-lock, auto-loading and a 6-position cassette with optional mask exchange.

These systems feature a uniquely designed milling (dry etching) platform which can accommodate samples up to 8” in diameter for a wide range of process applications, from nano pattern delineation to bulk wafer planarization.  These substrate holders are designed and manufactured exclusively by AJA and offer numerous desirable features such as cooling, tilting and rotation. For substrate cooling we offer water, LN2, and backside He or Ar gas in combination with simultaneous rotation and tilting.

AJA manufactures and incorporates a variety of leading-edge gridded, gridless and RF ion sources, which are easily configurable for specific applications, including reactive and inert milling processes. These sources can be mounted in a direct or angular orientation based on your requirements.

TYPICAL SYSTEM CONFIGURATIONS

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 design is the reduced ion source size necessary to achieve uniform etching of larger wafers that would typically require more 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 speeds 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.

ION SOURCES

AJA International, Inc. utilizes and manufacturers the leading ion sources on the market in all ATC-Series Ion Milling Systems. We provide gridded, gridless and RF ion sources compatible with inert or reactive gases and variable ion energies. These sources can be positioned in the chamber for direct or angular incidence to the substrate, depending on your application. Some available models include:

TIBS ION SOURCE:
The AJA-designed and manufactured Tilting Ion Beam Source (TIBS) delivers a high current density and is suitable for continuous Ar, O2 and N2 operation.  This source is equipped with AJA's unique in-situ tilting feature which allows for source head angle adjustment without breaking vacuum. The TIBS source is ideal for low energy milling applications and is capable of 10-15% dissociation of N2 and O2.

CCR COPRA ICP RF ION SOURCE:
Gridless ion source with ion energies ranging up to 250 eV dependant on operating pressure. This source is also O2 / N2 compatible up to 90% disassociation making it ideal for barrier layer and other reactive plasma applications.

KAUFMAN & ROBINSON GRIDDED ION SOURCE:
DC filament style gridded ion source with variable ion energies up to 1200 eV. Sources are suitable for Ar and light O2 service and are equipped with neutralization.

SUBSTRATE HOLDERS / HEATERS

AJA International, Inc. designs and manufactures substrate holders for all ATC Ion Milling Systems. Typical ion milling processes incorporate sample cooling because heating of the substrate during ion milling can produce undesirable results from non linear etching rates to unwanted cross linking of polymers used in lithographic resists. Standard models include water, LN2 and backside gas cooling, as well as rotation and tilting.

The AJA UNO series substrate holder shown above can accommodate substrates up to 6" in diameter with water cooling, rotation, and the ability to tilt up to 80 degrees during the milling process.  Substrates attach directly to the water cooled surface to maintain temperature stability during the milling process. This substrate holder allows glancing angle, precise, low energy milling.

The AJA BSG substrate holder shown below can accommodate substrates up to 200mm in diameter with backside gas cooling while rotating.  Weight rings around the outer edge of the substrates help to maintain a 2-5 Torrat the backside of the wafer for optimal gas heat transfer.  At this pressure, the gas, ideally helium, acts as a medium between the substrate and water cooled aluminum surface.  Other gases such as Ar or N2 can be used if He creates any contamination issues. This design is also load-lock compatible.

PHASE II-IM COMPUTER CONTROL

TYPICAL SYSTEM SCHEMATICS

SYSTEM OPTIONS