The deposition of coatings on to polymer substrates by planar magnetron sputtering

A vacuum deposition system was built enabling flexible polymer sheet, wound on a roll-to-roll transport mechanism, to be coated by any or all of three planar magnetron sputtering sources. Using this machine a large variety of coatings were produced in long lengths onto heat sensitive substrates and with controlled stoichiometry. Within the system the coating was monitored soon after deposition which allowed fast response to changing film properties, a critical factor in the continuous production of high quality coatings. An area of current interest has been the production of large area optical filters, the basis of which is the deposition of thin metal and thin metal oxide films. Of particular interest have been the 'heat mirror' type filters, the transparent conducting oxides and more recently the electrochromic devices. All these have been deposited at high rates onto flexible polyester substrates ostensibly at room temperature. Analysis of the films has been carried out by a variety of techniques in order to establish the precise chemical composition and structure of the films. Once optimum conditions had been established for individual films multilayer filters were produced and their optical performance determined. In the case of the 'heat mirror' type filters their performance was compared to theoretical predictions.