<font size="6">AJA Ion Mill</font>

iLab Name: AJA Ion Mill
iLab Kiosk: BRK Etch Core
FIC: Sunil Bhave
Owner: Neil Dilley
Location: Cleanroom - Q Bay
Maximum Wafer Size: 6"

Overview

General Description

This system is used for direct argon ion milling of thin and thick films. The rotating sample chuck can be oriented +/- 90 degrees from normal beam incidence. A top load-lock system saves time with pumpdown. The chamber can also be vented and the chuck mounted by hand.

An endpoint detector (EPD) from Hiden uses secondary ion mass spectrometry (SIMS) detection of milled material (discerns elements based on charge/mass ratio) to monitor elemental composition and, e.g., automatically stop when a certain element is reached.

Presentation: Introduction to AJA Ion Mill (Fab Forum, Feb 2019)

Specifications

Numerical specifications of tool performance and abilities, either from manufacturer or those seen in operation. Also include material compatibility and incompatibility.

Technology Overview - Remove if multiple tools use the same technology/process

 Description of the science behind the process. Include figures and diagrams if applicable.

Sample Requirements and Preparation

Samples that may be used in the tool, materials that are compatible/incompatible, and the required cleaning before the tool may be used. May include both an "ideal" clean and a minimum required clean. Also include BOE/oxide removal, dehydration, or any recommended post process steps. Note that thick films requiring high etch rates (and hence high amounts of heating), so this may mean one needs to load the sample directly on the chuck by venting the chamber (instead of using load lock). This will permit users to apply more torque and get better cooling of the chuck. However, it requires special training.

For EPD, note that argon atomic mass is the same as MgO, so the EPD is not able to sense (ionized) MgO in the large Ar ion background.

About Si wafers for masking the sample holder: 

We provide 15x15mm and 20x20mm cutouts in 6" Si + oxide wafers (0.67mm thick) at the AJA for general use. Samples should be smaller than these cutouts.

Some users may wish to cut their own wafer due to size constraints. Neil Dilley and Nick Glassmaker have used the LasX fiber laser in the BNC 1100A lab successfully on Si wafers. Please inquire with Nick ( nglassma@purdue.edu ) if you are interested in having a wafer cut.

• artwork: file = Siwafer_cut_fasterspeed ; 20x20mm square with 1mm radiused corners, "X" cut in middle to allow material to break out easier.
• material: 6" (actually 150mm) diameter x 0.67mm thick Si wafer with oxide from BNC store room
  • cut on the BACK  (unpolished) side of the wafer
• laser power = 100 %
• depth control = off
• Repeat = 150
• speed = 200 mm/s

After cutting (it just takes a few minutes), put the sample face down on a hollow cylinder support and gently press on the cracks until the pieces fall out. Careful, the wafer can break if pressed too hard! 

A much faster laser speed (200 mm/sec) + more repeats (800?) might be a better method, since we see some evidence of hotspots and melting Si at the end of our cut, and we would prefer to ablate the material instead of melting it.

Standard Operating Procedure

Standard procedure for tool operation, base off established Birck SOPs.

Questions & Troubleshooting

Question about tool use or process result?
Answer to question.

Process Library

Create process template for tool, allows a user to fill in the details of their process. 

References

Manufacturer brocheurs, specifications, papers with relevant info on process, and presentations covering the technology. Confluence lacks a native reference feature, so these are added as links.