NOVELTY - An apparatus (10) for depositing thin film on web, comprises a roll-to-roll substrate transport system to bi-directionally transport a web (34) between two rolls; first and second sputtering zones (18A, 18B) having magnetrons (54); a selenization furnace (66) disposed between the sputtering zones and configured to maintain a furnace pressure that is greater than pressure of first and second sputtering zones; a first selenium trap disposed between first sputtering zone and selenization furnace; and a second selenium trap disposed between second sputtering zone and selenization furnace.    USE - As an apparatus for depositing a thin film on a web (claimed).    ADVANTAGE - The apparatus enables the deposition of a CIGS thin film by sputtering deposition on metal and plastic thin foils and discrete substrates.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) depositing a thin film on a web, involving depositing a first layer of a composite metal onto a web, depositing a first selenium layer onto the first layer of the composite metal, heating the web to selenize the first layer of the composite metal, depositing a second layer of the composite metal onto the selenized first layer, depositing a second selenium layer onto the second layer of the composite metal, and heating the web to selenize the second layer of the composite metal;    (2) apparatus for fabricating a thin film photovoltaic device, comprising: a roll-to-roll substrate transport system to bi-directionally transport a web between two rolls, a first sputtering zone having magnetrons and configured to deposit a copper indium gallium layer on the web, a second sputtering zone having magnetrons and configured to deposit a copper indium gallium selenide layer on the web, a first cooling roll and a second cooling roll each disposed between first and second sputtering zones, a selenization furnace disposed between the first and second cooling rolls and configured to maintain a furnace pressure that is greater than a pressure of the first and second sputtering zones, a first selenium trap disposed between the first cooling roll and the selenization furnace, and a second selenium trap disposed between the second cooling roll and the selenization furnace; and    (3) system for depositing a thin film on a substrate, comprising a substrate transport system to transport discrete substrates along a closed path, a metal deposition zone disposed on the closed path and configured to deposit a layer of a composite metal onto the discrete substrates during passage through the metal deposition zone, a selenization zone disposed on the closed path to receive the discrete substrates after passing through the metal deposition zone, and a cooling chamber disposed along the closed path to receive the discrete substrates after passing through the selenization zone, where the cooling chamber is configured to cool the discrete substrates prior to a subsequent pass of the discrete substrates through the metal deposition zone and the selenization zone;    (4) depositing a thin film on a substrate, involving: (a) depositing a layer of a composite metal onto a discrete substrate during transport through a metal deposition zone; (b) transporting the discrete substrate to a selenization zone; (c) depositing a selenium layer onto the layer of the composite metal during transport of the discrete substrate through the selenization zone; (d) heating the discrete substrate during transport through the selenization zone to selenize the layer of the composite metal; (e) determining if the layer of the composite metal deposited onto the discrete substrate is a last deposition layer; and (f) repeating steps (a) to (d) if a determination is made that the layer of the composite metal deposited onto the discrete substrate is not the last deposition layer;    (5) vapor trap comprising an inner module having an outer surface, a pair of opposing ends, a transport channel extending between the opposing ends and plenums each extending from the transport channel to the outer surface, where the transport channel has a cross-section to pass a substrate and to limit conductance of a vapor, where the inner module is configured for maintaining a temperature that is greater than a condensation temperature of the vapor; an outer module comprising collection surfaces each disposed at an end of a respective one of the plenums opposite to the transport channel; and a cooling system in thermal communication with the outer module and configured to maintain a temperature of each of the collection surfaces that is less than a condensation temperature of the vapor;    (6) selenium trap, comprising an inner module having an outer surface, a pair of opposing ends, a transport channel extending between the opposing ends and plenums each extending from the transport channel to the outer surface, where the transport channel has a cross-section to pass a substrate and to limit conductance of a selenium vapor, where the inner module is configured for maintaining a temperature that is greater than a condensation temperature of the selenium vapor, an outer module comprising a surface having pockets each disposed at an end of a respective one of the plenums opposite to the transport channel, and a cooling system in thermal communication with the outer module and configured to maintain a temperature of each of the pockets that is less than a condensation temperature of the selenium vapor; and    (7) depositing a copper indium gallium diselenide film on a substrate, involving depositing a layer of indium on a substrate, depositing a layer of copper gallium on the layer of indium, selenizing the layers of indium and copper gallium, and repeating a sequence of the steps several times.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of apparatus for depositing thin film on a web.    Apparatus (10)    First sputtering zone (18A)    Second sputtering zone (18B)    Web (34)    Magnetrons (54)    Selenization furnace (66)