1. Let's assume that we want to fabricate a device with 3 lithography steps. During designing of a photomasks, what should we add in the photomask?

(a) Negative lithography mask with alignment patterns in the first two masks.

(b) Positive mask lithography mask with alignment patterns in the first two masks.

(c) Alignment patterns in all masks without depending on the PR type.

(d) Alignment patterns in the first two masks without depending on the PR type.

2. If a device cannot have any trace of Chromium contamination, how do you clean the substrate before microfabrication?

(a) Rinse with acetone.

(b) Treat with Piranha.

(c) Treat with HF acid.

(d) Rinse with deionized water followed by acetone.