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Wet Bench Revitalization

Situation Summary

A global leader in wafer manufacturing approached Tetra Systems Solutions to take two aging and unsupported STEAG 300mm wet benches that were being used primarily for R&D and limited production purposes and make them fully production worthy.  To meet the customer's production worthy requirements, both benches needed the following:

  • New Input & Output Modules with support for FOUPs/FOSBs as well as existing Crystalpaks, and maintaining the tool's existing footprint.
  • New Control Systems with Material Scheduler
  • New Gantry Motors
  • New Chemical Pumps
  • New Fan Speed Controllers
  • New Thermal Controllers
  • New HMI Touch Screens
  • SECS/GEM Support (Previously not available on the existing tools)
  • Maintain Existing Throughput

In addition, the demolition, installation, integration, and testing of the wet benches could not take longer than three weeks each.

Proposal

Tetra Systems Solutions designed a solution that would revitalize the existing wet benches, and use commercially available off the shelf (OTS) parts.

New Input & Output Modules

The existing input and output modules would be replaced with new ones, and a new 6-axis robot would be integrated so horizontal wafers coming out of the FOUP/FOSB/Crystalpaks could be placed vertically inside the process carrier.  The key components would be:

New Control Systems with Material Scheduler

A new and open control system would be developed and integrated into the tools.  With one of the biggest risk being the Materials Scheduler, an existing individual Wafer Scheduler from AltaStream would be modified for the batch process required by the tools. The key components would be:

  • Rockwell Automation ControlLogix PLC, Remote I/O Modules, & Touch Screens
  • AltaStream ASWorx and ASConnex (ASWorx included Materials Scheduler and SECS/GEM support)
  • Advantech Industrial Personal Computer (IPC)
  • Microsoft C++ Development Environment

Individual Parts Replacements

To address the obsolete parts issue with the existing tools, top of the line parts would be provided and tested on the tool during down times and prior to the major upgrade.

  • New Gantry Motors - Rockwell Automation Motors & Servos
  • New Chemical Pumps - Trebor Chemical Pumps
  • New Fan Speed Controllers - Control Resources Fan Speed Controllers, once integrated with the new control system allowed the customer to calibrate the HEPA air filtering system with in minutes compared to the hours it took in the past.
  • New Thermal Controllers - Watlow Thermal Controllers

Risk Management

With any project of this magnitude, risk management is key to the success of the project and trust of the customer.  A pre and post upgrade strategy was presented.

Pre-Upgrade

  • In Situ Testing - Prior to any major work on the tools, replacement parts would be tested for both functionality and fit. 
  • Factory Mockup - A complete mockup would be constructed at Tetra Systems Solutions' facility. A 30' gantry would built to simulate the gantry of the biggest wet bench, the new input and output modules would be assembled, and each process module would be simulated.  This would allow for the new input and output modules to be tested, but more importantly for the new control system, especially the Materials Scheduler to be tested and physically seen by the customer prior to entering the point of no return on the actual tools.

Post Upgrade

  • On-Site Support - For first two months an on-site technician was available to deal with any non-software related issue that might come about.
  • Remote Access - For major issues dealing with the software an secure and Internet-based remote control solution would be put into place to allow remote access to the PLC and HMI computer.

Results

  • Increased Reliably
  • Improved Maintainability
  • Reduced Cost
  • Automated Data Capture Through SECS/GEM
  • Ability to Integrate Additional Features - As an add-on project to make one of the 300mm wet benches was modified to support processing of both 300mm and 200mm wafers

NAVIGIST|group's Role

NAVIGIST|group's CEO/President, Craig Michaelis, was the Project & Account Manager, and his responsibilities included:

  • Bill of Material (BOM)
  • Factory Mockup
  • Application Testing
  • Software Development
  • Installation & Testing
  • Technical Writing