Photo Resist processing of Lithium Niobate and other pyroelectric Substrates.
The primary difficulty in coating substrates of pyroelectric materials is that the materials will build substantial charges leading to very high voltages when heated. It is therefore necessary to both heat and cool the substrates in such a way as to allow high voltage charges to “bleed” of to ground slowly. Otherwise the substrate will set of a spiked charge, which will at the very least ruin the photoresist film and often will also fracture the substrate. Accordingly tools to carry out photolithographic processing of such substrates must be equipped to both programmatically control heating and cooling rates while providing means to both isolate the substrate and at the same time allow high voltages charges to bleed off harmlessly. S-Cubed’s photoresist process tools are well suited to providing all of the capability required in the handling and processing of pyroelectric materials by incorporating the following features.
- Servo motor controlled hot plate transfer pin height enable programmable slow ramping of the substrate temp in the hot plate module
- Down flow gases in the hot plate chamber can have enhanced electrical charge carrying components to help “bleed off” charge.
- The wafer can be electrically isolated from the hot plate chamber using materials of construction suited to the purpose.
- The ambient within the tool enclosure has enhanced electrical charge carrying components.
- Dual spin modules permit full charge elimination at the completion of the coating or developing process.