ATOMIC LAYER DEPOSITION METHOD FOR COATING FLEXIBLE SUBSTRATES

Systems and methods for atomic layer deposition (ALD) on a flexible substrate involve guiding the substrate back and forth between spaced-apart first and second precursor zones, so that the substrate transits through each of the precursor zones multiple times. Systems may include a series of turning guides, such as rollers, spaced apart along the precursor zones for supporting the substrate along an undulating transport path. As the substrate traverses back and forth between precursor zones, it passes through a series of flow-restricting passageways of an isolation zone into which an inert gas is injected to inhibit migration of precursor gases out of the precursor zones. Also disclosed are systems and methods for utilizing more than two precursor chemicals and for recycling precursor gases exhausted from the precursor zones.