At present, there are etching technologies developed to cater works even at higher temperature and increased chemical reactivity. The processes that were previously thought to be very slow due to temperature (usually between 260°C and 300°C) constraints can now be a practical choice.
What are the technologies employed in high temperature sapphire etching?
- Liquid in tank comes in contact with nothing but high purity quartz; no other parts used in the process areas – no Teflon connections, sensor, or any other components. In fact, even built-in condensing coils and automated lid are quartz
- This type of etching machine also employs technology that is especially designed to avoid a failure of critical seal material that isolates the heater system from the outside environment.
- This etching technology also utilizes a quartz aspirator (a suction instrument used to create a partial vacuum); this component is also important as this helps removing the chemistry without having to wait for it to cool (remember that there is no drain valve works at these temperature).
- The aspirator drains the tank into to a cool-down module, which has quartz cooling coils used to help in lowering the chemistry temperature more quickly.
- This type is also designed to have a quartz secondary containment module, which can hold the entire contents of the tank in the event a tank breach happens.
Benefits of sapphire etching to the semiconductor industry
- Provides cost advantage for LED manufacturers through PSS (patterned sapphire substrates, with an average light output power of up to 37% larger compared to a standard sapphire wafer.
- The use of PSS also reduces the dislocation density in the GaN (gallium nitride)
- It also enhances the LEE or light extraction efficiency from the LED chip.
- Since the process can now be performed even at high temperatures, wafers can etched at unprecedented rate, more quickly than the standard process and thus improves the overall production.
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