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.
This 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.
In the silylation process, HMDS reacts with the oxide surface and forms a strong bond to the surface. At the same time, free bonds are left which readily react with the photoresist, enhancing adhesion.