Stepper 3 (ASML DUV)

Stepper 3 (ASML DUV) Tool Type Lithography Location Bay 7 Supervisor Demis D. John Supervisor Phone (805) 893-5934 Supervisor E-Mail demis@ucsb.edu Description Deep-UV Stepper Photolithography Manufacturer ASML Model PAS 5500/300 Lithography Recipes Sign up for this tool

About

General Capabilities/Overview

The ASML 5500 stepper is a 248nm (KrF) DUV stepper for imaging dense features down to below 200nm and isolated line structures down to below 150nm (with effort). 300nm features are relatively "easy" to resolve. Layer-to-layer overlay accuracy is better than 30nm.

The system is configured for 4” wafers. The system is designed for high throughput, so shooting multiple 4" wafers is extremely fast, typically minutes per wafer, but any size other than 4-inch is difficult to work with (see below for more info). Additionally, exposure jobs are highly programmable, allowing for very flexible exposures of multiple aligned patterns from multiple masks/reticles in a single session, allowing for process optimization of large vs. small features in a single lithography.

The full field useable exposure area is limited to the intersection of a 31mm diameter circle and a rectangle of dimensions 22mm x 27mm. Users have stitched multiple photomasks together with success. See the Mask Making Guidelines page for more info on exposure field sizes and how to order your mask plates.

Photoresists Available

See PhotoLith. Recipes for full process info & links to PR datasheets.

• UV210-0.3 - Positive: 300nm nominal thickness
• UV6-0.8 - Positive: 800nm nominal thickness
• UV26-2.5 - Positive: 2.5um nominal thickness
• UVN2300-0.5 - Negative: 500nm nominal thickness

• DUV42P-6/DS-K101 - Bottom Anti-Reflective Coatings “BARC”
• PMGI/LOL1000/LOL2000 - Underlayers

AZ300MIF Developer for all processes

Many of these DUV PR's are also able to be exposed with EBL.

Part Size Limits

With staff support, mounted pieces down to 14mm in size can be exposed using a 4” wafer as a carrier. Flatness will typically be worse in this situation, so small <<500nm features will usually have bad uniformity across the mounted part due to focus variations. Edge bead on irregular pieces (eg. quarter-wafers/squares) will significantly reduce yield/uniformity.

Multi-layer Alignment on mounted parts is particularly difficult, requiring either semi-permanent mounting to the carrier (eg. BCB, SU8 etc.) or significant difficulty/effort to re-align the part to the carrier wafer on each lithography (≤100µm re-mounting accuracy needed).

At this time the maximum wafer size is 4” (100mm) wafers with SEMI standard wafer flat (not Notch).

Service Provider

• ASML - ASML performs quarterly periodic maintenance and provides on-demand support.

Process Information

• Process Recipes Page > "Stepper 3" - Established recipes and corresponding linewidths, photoresists etc.
• Sample size: 100 mm wafers with SEMI std. major flat
  • Piece-parts process is possible but difficult - contact staff for info
• Alignment Accuracy: < 50 nm
• Minimum Feature Size: ≤150 nm isolated lines, ≤200 nm dense patterns
  • To achieve ≤200nm features with high uniformity, we recommend wafers with total thickness variation (TTV) ≤5µm, and designing your CAD with a smaller Image Size for the high-res. feature.
• Wafer Thickness: Minimum ≈ 200µm, Maximum ≈ 1.1 mm
• Maximum Wafer Bow: approx. 100 µm. (4-inch diam.)
  • Near this value, and the job may fail or lose the wafer inside the machine due to wafer vacuum error.
  • Substrate material and substrate thickness affect this limit - for example, for thick sapphire (less pliable), ≥60µm bow will intermittently fail.
• Maximum Dose: ~100mJ (so non-chemically amplified EBL resists are not permissible)

Operating Procedures

• Standard Operating Procedures - Exposing wafers, loading reticles, focus/exposure matrix
  • Focus-Exposure Matrix - used for calibrating sensitive exposure parameters
• Error Recovery, Troubleshooting & Calibration Check
  • Common errors/solutions, System Calibration Verification (aka. IQC)

• ASML 5500: Recovering from an Error+Wafer Retrieval
  • How to abort the job and recover your wafer.
• Job Programming- Simplified - Full Wafers
• Job Programming - Full

• Working with Substrates Smaller than 100mm/4-inch

• Mask Making Guidelines
  • All the info you need to design and order a reticle for this system.

Training Procedure

To get access to this tool, please do the following:

1. Study the training videos below.
   1. If you are a technician and will never do job programming, only Part 1 is necessary.
2. "Shadow" someone in your group who uses the machine, until you are completely comfortable with wafer cleaning (critical), reticle load/unload and running a pre-made job. When you are ready do step 3:
3. Contact the supervisor for an short hands-on check-off, after which you'll get signupmonkey access.

Online Video Trainings

These video trainings have bookmarks to skip to specific sections - use them as reference.

Remember, you are NOT authorized to use the system until a supervisor grants you access.

• Part 1: System Info & Running a Job
• Part 2: Job Programming

Design Tools

• ASML Job Creator - Python scripts for generating ASML Job Files.
  • Remotely-uploadable job scripting is now possible - contact the supervisor if interested.
  • Note: Automated Upload/conversion is disabled due to system software upgrades - we are working to restore this. 2022-09 DJ
• UCSB DUV Reticles - Photomasks available with various Alignment Markers (contact, EBL), Resolution Testing etc.

Mask Design and CAD files

• Mask Making Guidelines - All the info you need to design and order a reticle for this system.
• Templates and CAD help - on the above page, CAD files and spreadsheets to help you design/program.
• See the Calculators + Utilities > CAD Files & Templates page for other useful CAD files, such as overlay verniers, vented fonts etc.

Software Options

The Following software options have been installed on the machine.

• Shifted Measurement Scans - better tilt/level measurement locations for edge-die. Simply enable the Checkbox in your job file.
• Compound Image Design - flexible Image Distribution: grouping of Images with shifts, duplicate instances of Images in each Cell.
• Job Creator - create binary ASML job files from ASCII text files. Python scripting capabilities using this option are currently implemented, contact the supervisor for more info.

Recipes

See the Recipes > Lithography > Stepper Recipes > Stepper #3 page for starting processes for various photoresists, including Dose/Focus values.

Litho. recipes for all our photolith. tools can be found on the Photolithography Recipes page.

Process Control Data

• The Process Group regularly measures data on lithography Critical Dimension ("CD") and Wafer-stage Particulate Contamination for this tool, using a sensitive lithography process that will reveal small changes in Dose repeatability and wafer flatness.
• Data Table for CD Uniformity and Particulate Contamination
• Plots of CD Repeatability

Example of Data Table with SEM's of 320nm features. Click for full data table.

Example SPC Chart - Measured Critical Dimension "CD" versus Date. Click for charts.