Patent ID: 8481355

Claim:
A process for vapor deposition of a thin film layer on a photovoltaic (PV) module substrate, comprising: conveying substrates in serial arrangement through a vapor deposition apparatus in a vacuum chamber wherein a thin film of a sublimed source material is deposited onto an upper surface of the substrates, the substrates being conveyed through the vapor deposition apparatus at a controlled constant linear speed such that leading and trailing sections of the substrates in a conveyance direction are exposed to the same vapor deposition conditions within the vapor deposition apparatus; post-heating the substrates as the substrates are conveyed out of the vapor deposition apparatus such that a substantially uniform temperature is maintained along the length of the substrates until the entire substrate is conveyed out of the vapor deposition apparatus, wherein the substrates are conveyed from the vapor deposition apparatus into a post-heat module for the post-heating step while maintaining a substantially constant temperature profile throughout the longitudinal length of the post-heat module; and, cooling the substrates subsequent to the post-heating step; wherein the substrates are conveyed through the vapor deposition apparatus and into the post-heat module at a first conveyance rate, and conveyed from the post-heat module into a downstream cool-down section at a substantially greater second conveyance rate effective to prevent a thermal gradient from being established along the length of the substrates.