Final answer:
The current 1 μm feature size and 25 μm gap do not specify the wavelength used, but switching to an i-line lamp (365 nm) or an ArF laser (193 nm) would allow for significantly smaller features to be resolved due to shorter wavelengths.
Step-by-step explanation:
The question relates to the resolution capability of proximity aligners in semiconductor manufacturing and the limitations imposed by the wavelength of the light used. The existing conditions provided in the question do not specify the wavelength being used to expose a 1 μm feature with a 25 μm gap. However, the question then transitions into hypothetical modifications using different light sources. When switching to an i-line lamp, which emits light at a wavelength of 365 nm, and an ArF laser, which emits light at a wavelength of 193 nm, we refer to the diffraction-limited resolution of optical systems given by the formula R = k λ/NA, where R is resolution, k is a process-dependent constant (typically near 1), λ is the wavelength, and NA is the numerical aperture of the system.
For the same numerical aperture, using an i-line lamp with a shorter wavelength than the theoretical original will allow for smaller features to be resolved, possibly on the order of sub-micron, while using the even shorter wavelength of the ArF laser can theoretically allow features on the order of the wavelength itself, such as around 193 nm, to be resolved, assuming the system's numerical aperture and other processing factors permit it.