NOVELTY - The fabrication method involves spraying clean deionized (DI) water, freshly mixed and gradually aged reaction solutions, and spraying freshly mixed reaction solution continuously onto surface of vertically travelling flexible substrate surface. The sprayed and gradually aged solution is collected and sprayed back onto traveling substrate surface continuously until predicted film thickness is obtained. The residue solution is washed away from deposited surface using minimum rinsed water to reduce volumes of waste water to be treated and DI rinsing water.    USE - Fabrication method for forming thin films on flexible substrate surfaces by CBD in roll-to-roll process in preparation of solar cell.    ADVANTAGE - Ensures inexpensive fabrication due to simple design of apparatus. Reduces amount of waste solutions for chemical treatment and ensures easier deposition since backside of substrate is made dry and clean. Reduces waste amount and amount of rinsing water by allowing reuse in the waste compartment and separating the waste compartment from the rinsing sections.    DETAILED DESCRIPTION - The deposited film materials include silver sulfide, silver oxide, aluminum oxide, arsenic trisulfide, bismuth trisulfide, cadmium sulfide, cadmium oxide, cadmium zinc sulfide, copper bismuth sulfide, copper indium disulfide, copper disulfide, copper monosulfide, copper(I) oxide, copper(II) oxide, ferric oxyhydroxide, iron(III) oxide, iron(II,III) oxide, iron(III) sulfide, greigite, gallium sulfide, mercury sulfide, indium(III) oxide, indium(III) sulfide, lanthanum oxide, magnesium oxide, manganese sulfide, manganese dioxide, molybdenum disulfide, niobium dioxide, niobium sulfide, nickel sulfide, nickel oxide, lead mercury sulfide, lead sulfide, lead oxide, rhenium trioxide, rhodium oxide, ruthenium oxide, ruthenium sesquioxide, antimony sulfide, silicon dioxide, tin sulfide, tin disulfide, tin dioxide, titanium dioxide, vanadium oxide, tungsten trioxide, zinc oxide, zinc sulfide, zirconium dioxide, or combinations thereof. The buffer layer material including cadmium sulfide, indium sulfide and zinc sulfide is deposited from the CBD reactor to fabricate thin film solar cells, especially copper indium gallium selenide and cadmium telluride cells. The flexible substrate workpiece includes metallic foils of stainless steel, aluminum, molybdenum, copper, nickel, and non-metallic films of polymers, plastics and flexible ceramics.    DESCRIPTION OF DRAWING(S) - The drawing shows a top view of an apparatus for a CBD deposition onto a continuous flexible workpiece through a roll-to-roll process.    Winding unit (100B)    Guide rollers (101A,101B)    Wind knives (102A)    Spray nozzle (105)    Pump (106)