HMDS Prime Ovens

YES-310TA & YES-58TA
Stainless Steel Process Cassettes
HMDS Application Note

The HMDS prime process provides a "one-stop" environment for substrate dehydration and vapor deposition of hexamethyldisilizane (HMDS). Because of HMDS lithography preprocessing, YES systems give an HMDS prime layer with superior uniformity and stability.

In wafer fabrication, silane deposition is needed to promote the chemical adhesion of an organic compound (photoresist) to a non-organic substrate (wafer). The silane acts as a sort of "bridge," with properties that will bond to both the photoresist and wafer surface. Typically, hexamethyldisilizane (HMDS) is used.

Old wet processes for depositing silane generated a substantial amount of hazardous waste. Plus, the coating had a limited lifespan, meaning a process engineer had a small window of time to apply photoresist before the bond would degrade.

But today, using the HMDS prime process, you can significantly extend time available between process steps. Plus, chemical usage for a vapor deposition process is typically less than 1% of the amount needed for wet application processes, significantly reducing waste and chemical costs.

The Need for Complete Dehydration

HMDS adhesion

In order to promote a strong silane bond to the substrate, first, wafers must be completely dehydrated—not only surface moisture, but the chemically bound water molecules as well. To achieve this, YES developed a process combining heat with low pressure. Once dehydrated, wafers are then primed with an HMDS vapor to strengthen photoresist adhesion. Properly treated wafers will last for weeks with no change to surface adhesion.

MEMS Applications

  • Wafer Dehydration
  • The moisture on the surface of wafers will cause unintended reactions with various deposition steps. These reactions result in unstable surface which degrade over time. Vacuum dehydration provides a clean stable surface resulting in superior films.

Image Reversal Process

The image reversal process reverses the action of positive resist so negative images can be formed with the same resolution and processing ease that a positive resist allows. What's more, image reversal allows variations of the slope of the photoresist sidewall for higher resolution and/or lift off profiles.

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News & Updates

  • Solutions for Nano and Micro-Structured Optical Films (pdf)
  • Medical Device Industry White Paper (pdf)
  • Genomics White Paper (pdf)
  • October 22-23, 2019 - Visit YES at Booth #39 at the International Wafer Level Packaging Conference at the San Jose Doubletree Hotel
  • October 7-9, 2019 - Visit YES at Booth #8 at Lab On a Chip at the Coronado Island Marriott Resort & Spa (San Diego, CA)
  • July 9-11, 2019 - Visit YES at booth #932 at Semicon West in San Francisco
  • June 25-27, 2019 - Visit YES at booth #244 at Sensors Expo and Conference in San Jose
  • May 28-31, 2019 - Visit YES at booth #219 at ECTC in Las Vegas
  • April 29-May 2, 2019 - Visit YES at booth #306 at CS Mantech in Minneapolis
  • March 4-7, 2019 - Visit YES at Booth #64 at the IMAPS Device Packaging Conference in Arizona

Other Updates


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About Our Company

Located in Livermore, California, Yield Engineering Systems (YES) is a privately held company that manufactures engineering process control equipment to meet the needs of innovative engineers and lab managers.

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