Dektak XT

Dektak XT
Equipment Details
Technology	Metrology
Materials Restriction	General
Sample Size	pieces and up to 6" wafers
Equipment Manual
Overview	System Overview
Operating Procedure	SOP
Maintenance	Maintenance

The Dektak XT is a stylus profilometer. It uses a diamond-tip stylus that contacts the sample. The tool maintains a constant stylus force as the sample stage moves the sample under the stylus tip to trace a profile. This tool profiles surface topography allowing measurement of step heights and lateral dimensions of features on your sample. It can also measure surface roughness (above ~15 Å range). The Dektak XT also has thin film stress analysis software and 3D mapping capabilities.

Announcements

None at this time.

Capabilities

• The Dektak XT is capable of measuring profile step heights of ~ 500 Å to 100 μm.
  • Although there are range settings of 524 μm and 1 mm on the tool, only step heights of up to 100 μm may be scanned. For heights above this, the stylus is not able to climb up the step and typically becomes stuck on the side of the profile, but the stage will continue to move which can damage the stylus, sensor head, and your sample. For steps taller than 100 μm, the Zygo or LEXT 3D optical profilers should be used or there is also a height gauge located next to the Flexus stress measurement tool.
  • Step height measurement accuracy for small steps becomes limited by noise floor and/or sample surface roughness. Based on step height repeatability measurements on a calibration check sample with 400 μm scan distance and 200 μm feature width, approximately +/-10% accuracy is expected for a 500 Å step.
• Vertical Resolution (@ each range setting):
  • 1 Å @ 6.5 μm
  • 10 Å @ 65.5 μm
  • 80 Å @ 524 μm
  • 150 Å @ 1mm

• Stylus: Diamond tip, 12.5 μm radius
  • Tip size limits the capability of measuring narrow and high aspect ratio (greater than approximately 1 to 1) trenches. Measurement should be attempted using the Zygo or LEXT 3D optical profilers in these cases.

• Stylus Tracking Force: 1 mg – 15 mg (software selectable)
• Scan length: 50 μm up to 200 mm with automatic scan stitching of 55 mm individual scans

System overview

Substrate requirements

• Wafer Size - pieces up to full 6" wafers
• Wafer type - Any
• Maximum sample thickness = 50 mm
• Maximum sample weight = 1.5 pounds

Material restrictions

The Dektak XT is designated as a General 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 info@lnf.umich.edu for any material requests or questions.

Approved materials

• No liquids or uncured polymer, resist, or spin on films.
• Be aware that the profiler stylus will make contact with your sample and may scratch into softer materials. Stylus force is software selectable in a range of 1 to 15 mg. Lower values of stylus force should be selected before lowering the tower for soft materials to help reduce scratching into the film. At lower force values, you may need to increase the scan duration (slowing down the scan speed) to reduce overshoot/ringing in the profile trace.
• As a General Class tool, there are no specific material restrictions for this equipment.

Full system overview document

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Supported processes

There are no supported processes for this tool.

Users set up their measurement options/parameters specifically for their sample requirements each time they use the tool. Please see the Standard Operating Procedure below for instructions.

Standard operating procedure

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Checkout procedure

1. Read through this page including the System Overview and the Standard Operating Procedure above.
2. Create a Helpdesk Ticket requesting training.
3. A tool engineer will respond to coordinate a time for your training and checkout. If the checkout is successful, the engineer will authorize you on the tool.

Maintenance

All tool maintenance is performed by LNF Staff.

Calibration of each scan range is performed monthly by LNF Staff using a 4 µm step height standard.