Image Reversal

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YIELD Engineering Systems Inc.

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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.
For example, if the normal slope of approximately 68 degrees is altered to 90 degrees vertical, resolution is increased 20%. And, if an angle of 112 degrees is achieved, there is a strong overhang that makes metal deposition followed by liftoff controllable.
Why not just use a negative resist?
Positive resist offers far better resolution, and it doesn’t require solvents for development. In contrast, the resolution limit of negative resist is approximately 1 micron, and it requires solvents known to be carcinogens.


YES image reversal system

YES image reversal systems deliver anhydrous ammonia (NH3) into a vacuum oven. There are two advantages of an ammonia system: 1) easier control of vapor pressure, and 2) an absence of residual water vapor, which will react with the NH3 to produce NH3OH, a corrosive to the system that also creates contaminating particles.

For more information on achieving repeatable and usable reversals, visit the YES-8TAE & 10TAE product page.

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Last modified: 2019-04-06