AMS 2004 Aluminum Nitride Sputter Tool
|caption = |materials = Al, AIN |mask = |size = 4" wafers only |chemicals = |gases = |overview = System Overview |sop = SOP |processes = Supported Processes |maintenance = Maintenance }} The AMS 2004 is dedicated for sputter-deposition of high quality piezoelectric aluminum nitride (AIN) films. Piezoelectric AlN is deposited using reactive sputtering of a pure Al target with a combination of nitrogen and argon as the sputtering gasses. Piezoelectric AlN is difficult to sputter because of the insulating nature of the film, stress issues in the film and it’s sensitivity to O2. As a result, it requires a dedicated system which uses dual AC target technology, extensive Al pasting routines, substrate bias to prep surfaces and a loadlock to minimize pumping times while still allowing mid-10-7 Torr pressures.
- Original AMS Tool removed.
- New Endeavor Tool being installed in 2019
- Piezoelectric AlN films 0.5-2.5 µm thick
- Deposition rates of up to 9 Å/sec
- Variable gas flows to allow for stress control
- Turbo-pumped, loadlocked sputtering tool.
- 10 KW AC power supply that runs 5KW power across a dual Al target source
- RF bias on wafer holding platen to control surface characteristics.
- 2 KW DC supply to allow control of uniformity.
- 100 sccm N2 and Ar flow meters.
- Handler for 4" wafers.
- 4” wafers only
- The process heats the wafer considerably (~500°C or more) with heavy ion bombardment so no organics or low temperature films are allowed in the tool.
- The process only produces piezoelectric AlN films on certain materials (specifically blanket undoped or low-doped Si, SiO2 and patterned Mo, Pt, Al.)
The AMS 2004 Aluminum Nitride Sputter Tool is designated as a Undefined class tool. Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under normal circumstances. If a material is not listed, please create a helpdesk ticket or email firstname.lastname@example.org for any material requests or questions.
The AMS 2004 Aluminum Nitride Sputter tool has a single supported process:
- Aluminum Nitride (AlN) deposition.
- AlN is a 3-step process:
- A condition recipe which pastes the empty chamber with Al and then preps it for AlN deposition. The wafer is then loaded in the chamber
- An etch recipe which runs an RF Ar etch on the wafer and then runs an Ar/N2 flow to prep the surface.
- Deposition recipes are called aln time XXum where "XX" is the target thickness in μm.
- Users are only allowed to change certain steps of the deposition recipes. Changes to condition or etch recipes are not allowed without staff supervision.
- Users can change deposition time, DC power and gas flows to adjust thickness, uniformity and stress of the AlN film.
- AlN is a 3-step process:
Recipe layout, recipe steps and editing rules are outlined in the SOP and in the AMS 2003 ALN Sputter - Standard Processes
AlN Thickness vs Dep Time of Step 4:
NOTE: Chamber just rebuilt in 2015. Intention is to add data for trend vs KWhrs as more data is collected
- Typically the deposition rate starts at around 9 Å/s and falls to below 8 Å/s as the targets wears.
- Also note that, because of preparatory steps and non-linear heating of the target, the linear fit does not intercept at 0 Å.
- Finally note that the deposition rates published here are for a variety of Ar/N2 flows and that large Ar/N2 flow changes will vary deposition rate significantly.
- Hysteresis is mapped to look at the N2/Ar ratios that produce a poisoned AlN state
- Users will want to run in the lower target voltage regime (AlN poisoned mode.)
- Since the condition recipe and the beginning of the deposition recipe run the target to a high N2 flow state, the deposition steps are operating on the N2 "going down" (red) curve.
Standard Operating Procedure
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- Read through this page and the Standard Operating Procedure above.
- Create a Helpdesk Ticket requesting training.
- A tool engineer will schedule a time for initial training.
- Practice with your mentor or another authorized user until you are comfortable with tool operation.
- Schedule a checkout session with a tool engineer via the helpdesk ticket system. If this checkout is successful, the engineer will authorize you on the tool.
Target is changed at 900 KWHrs. Kits swapped out around 500 KWHrs.
Power Bump Recovery
The only maintenance that users are allowed to perform is power interruption recovery.
- Follow the power bump part of the AMS 2003 AlN Startup and Shutdown Procedure