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Normal evaporative deposition gives approximately horizontal films on the resist tops and exposed substrate, with little coating of vertical walls. A small distant electron-beam-heated source in high vacuum gives nearly line-of-sight arrival. Near-normal rays reach the opening floor, while vertical walls present almost no projected area.

The floor film and top film can remain disconnected, which helps a later lift-off process. A finite source size, tilted incidence, scattering or sample rotation changes that idealization and may coat one wall or shadow part of the floor. The stated $200\mathrm{nm}$ thickness is well below the $1\mu \mathrm{m}$ resist height, but this alone does not guarantee a clean break at every real edge.

In physical vapor deposition, material is physically released from a source and transported to the substrate, where it condenses. Three examples are thermal evaporative deposition, electron-beam evaporation and sputtering. Their angular distributions, source heating and energetic bombardment differ, even though all belong to the physical-deposition family.

In chemical vapor deposition, volatile reactants undergo chemical reactions that produce a solid film at or near the substrate, with gaseous products removed. Examples are atmospheric-pressure thermal CVD, low-pressure CVD and plasma-enhanced chemical vapor deposition. These are three established process variants, distinguished by pressure and activation method. Surface chemistry, precursor delivery and temperature determine growth, rather than condensation alone.

Atomic layer deposition is a related cyclic surface-reaction method, but need not be counted as a separate conventional CVD example to satisfy the requested three. Reactive sputtering can involve chemistry, so the boundary is best explained by the dominant source and transport mechanism rather than by claiming that a PVD chamber can contain no chemical reactions.

In evaporative deposition, atoms travel mainly along straight trajectories from a compact source. For an ideal cosine-emitting source below a parallel wafer, a point at lateral radius $r$ and source separation $H$ receives approximatelyConsequently $F(r)/F(0)=[1+(r/H{)}^2{]}^{-2}$. Increasing $H$ makes arrival angles and distances more similar across a fixed wafer, improving uniformity. But the central flux falls as $H^{-2}$ for a fixed source output, so the deposition rate decreases and less evaporated material is collected.

Rotation averages azimuthal variations, and source shaping or multiple sources can help, but simple rotation does not remove a radial flux gradient. Raising source output can partly compensate at the cost of source heating, consumption and possible material limitations. The trade-off follows from geometry rather than an intrinsic prohibition on simultaneously optimizing a more elaborate system.