HMDS creates a bond between the photoresist and the wafer surface by bonding the silizanes to the silicon and the methyls with the photoresist. As a photoresist adhesion promoter for semiconductor applications, hexamethyldisilizane (HMDS) was first described in U.S. Patent 3,549,368 by R. H. Collins and F. T. Devers (1970) of IBM. Initially, processes called for 100% HMDS or HMDS mixed with Xylene. Wafers were dipped in the solution or the solution was dispensed onto a wafer using resist-processing. The first vapor prime techniques used bubblers or vapour degreasers with a reserve of liquid HMDS.
What the YES HDMS 310TA oven can offer
Yield Engineering Systems (YES) introduced a process now commonly known in the semiconductor industry as vacuum bake/vapor prime, a key step in the front end processing of silicon chips. The process dramatically improves the application of hexamethyldisilizane (HMDS) as a surface priming treatment, which is used to enhance adhesion of photoresist on a wafer surface. 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 YES-TA vacuum bake/vapor prime ovens, 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.
Benefits of the YES vacuum bake/vapour prime
- Adiabatic cooling prevention
- Filtration mechanisms eliminate introduction of particulates
- Surge suppression systems significantly limit turbulence
- Chamber size maximises strength, efficiency, and particle control.
- Chemical deposition uniformity
- Contact angle uniformity within ± 3 degrees
- Moisture resistant surface modification
- Increased time available between process steps
- Enhanced photoresist adhesion
- Less chemical usage and chemical cost