Match List I with List II

List – I		List – II
A.	Diffusion	I.	PMMA
B.	Oxidation	II.	Proximity Printing
C.	UV Resist	III.	\(\rm \frac{\partial C(x,t)}{\partial t}=\frac{\partial J(x,t)}{\partial t}\)
D.	X‐ray Lithography	IV.	Deal and Grove's Model

Choose the correct answer from the options given below:

Concept:

Deal and Grove model:

The model assumes that the oxidation reaction occurs at the interface between the oxide layer and the substrate material, rather than between the oxide and the ambient gas.

Thus, it considers three phenomena that the oxidizing species undergoes, in this order:

• It diffuses from the bulk of the ambient gas to the surface.
• It diffuses through the existing oxide layer to the oxide-substrate interface.
• It reacts with the substrate

X-Ray lithography

• In X-ray lithography, an X-ray source illuminates a mask, which casts shadows on to a resist-covered wafer.
• The mask and resist material for X-ray lithography are mainly determined by the absorption spectra of these materials in the X-ray region.

Proximity printing

Since the wavelength of X-ray is small, diffraction effects can be ignored and simple geometrical considerations can be used in relating the image to the pattern on the mask.

• The opaque parts of the mask cast shadows onto the wafer below.
• The edge of the shadow is not sharp because of the finite diameter of the focal spot of the electrons on the anode [X-ray source] at a finite distance from the mask.

UV Resist

• Polymethyl Methacrylate – PMMA – is widely used in various applications for its many advantageous properties. The most well-known of these properties is light transmission.
• PMMA is utilised for many outdoor applications since it is naturally stable to UV light and retains its original colour and finishes for a long time.