12-What is the application range of protective coatings?

What is the application range of protective coatings?

Protective coatings are available for a large variety of applications, e.g. for the protection of wafer backsides:

for mechanical protection during transport
as insulating layer
for KOH- and HF-etchings (AR-PC 503, AR-PC 504 (both adhesion-enhanced), SX AR-PC 5000/40)
as temperature-stable intermediate layer for two-layer procedures (SX AR-PC 5000/80).

Protective coatings are generally applied by spin coating. Protective coatings AR-PC 504, X AR-PC 5000/19, and 5000/30 contain polymethacrylate and tend to show the so-called “candy-floss“-effect at suboptimal rotational speeds. This effect can be reduced with a lower rotational speed, local exhaustion, and the removal of the “candy strings” with a glass rod during spin coating. Recommended are coatings at 1000 rpm.

Overview of photoresist FAQs

1. What are photoresists composed of, and how do they work?

2. For how long are photoresists stable, and what are the optimal storage conditions?

3. How may age-related changes influence the quality of a photoresist?

4. What is the optimal pre-treatment of substrates for photoresists?

5. What are the adhesion features of photoresists on different wafers?

6. What are the optimum coating parameters for photoresists in order to achieve good film images?

7. Why may air bubbles develop in photoresist films, and how can they be avoided?

8. What is the function of the softbake of photoresist films after the coating?

9. How are photo resists exposed, and how can the optimum exposure dose be determined? How long can coated and exposed substrates be stored prior to exposure?

10. Which developers are optimal for photoresist, and how do factors like developer concentration and temperature influence the result?

11. How can resist coatings be removed again?