16-Which resolution and which contrast can be obtained with photoresists?

Which resolution and which contrast can be obtained with photoresists?

The resolution of resists is influenced by several parameter such as e.g. the type of mask liner used, most of the respective NA (numerical aperture), film thickness, exposure wavelength, concentration of developer and time of development, substrate (e.g. reflexion properties), and a few other parameters with minor influence on the result.

Typical values for 1.4 µm thick positive resists are resolutions between 0.4 and 0.5 and a contrast of 4.5 to 5.

Respective parameters for each type of photoresist are specified in our Parameter Collection (see “Photoresists”).

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?