# Assertion (A): For making an integrated circuit the type of lithography chosen depends upon the feature size. Reason (R): UV lithography can easily be

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Assertion (A): For making an integrated circuit the type of lithography chosen depends upon the feature size.

Reason (R): UV lithography can easily be used for making nano-size circuits.

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A)
3. (A) is true, but (R) is false
4. (A) is false, but (R) is true

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Correct Answer - Option 2 : Both (A) and (R) are true, but (R) is not the correct explanation of (A)

The smallest feature size that can be patterned is related to the wavelength of light (λ), that in turn depends on the type of lithography.

This relation is given by:

$\sigma = \frac{{k.\lambda }}{{NA}}$

K = Rayleigh constant

λ = wavelength

NA = Numerical Aperture.

• With 135 mm light wavelength called extreme UV lithography the feature size is 68 nm
• It is possible to reduce the wavelength even further by using X-rays, called X-ray Lithography
• ∴ By using UV lithography nano-size circuits are made easily.

So, Both (A) & (B) are true but (b) is not a correct explanation of (A)