in accordance with this invention , a color filter array coating is removed from a device substrate by contacting the coating with dry ozone produced by electric discharge and uv radiation and washing to remove the oxidized coating . subsequently , the substrate can be reused to produce another color image sensing device . as used herein , the term “ color filter array coating ” is intended to include any or all of the following : ( a ) a pigmented or dyeable photosensitive coating that is either undyed or dyed ; ( c ) non - dyeable photosensitive coatings , for example , those used for planarizing layers and protective overlayers . the process of this invention is useful with any color filter elements fabricated on substrates . it may be used to remove color filters prepared from either aqueous or solvent - based systems . for example , the process is useful with any of the aqueous - based coatings and substrates disclosed in u . s . pat . nos . 4 , 764 , 670 , 4 , 355 , 087 and 4 , 315 , 978 , the disclosures of which are hereby incorporated by reference in their entirety . the coating can be formed from materials such as hydrophilic colloids in admixture with a radiation - responsive hardening agent , e . g ., dichromated gelatin ; diazo resins mixed with a mordant , e . g ., those described in u . s . pat . no . 4 , 220 , 700 ; poly [ vinyl alcohols ] in admixture with a dichromate and a polymeric mordant ; anionic or cationic mordants ; or photocrosslinkable mordants . tpically , the thickness of the dried coating is at least about 0 . 5 μm and can be greater than 2 μm . the above - described stripping process is most preferably employed with photoresist coatings manufactured from highly crosslinked negative acting acrylic polymers . in a negative photoresist material , the portion of a layer of the photoresist exposed to an energy source is polymerized , which changes in its chemical character . polymerization renders the photoresist insoluble with respect to solvents which remove the non - exposed portion of the negative photoresist layer , thereby producing the desired pattern . in addition , the above - described stripping process is advantageously employed when barrier layers are used in the process for preparing the solid - state color imager . the stripping process is useful with barrier layers ( aqueous and non - aqueous ) formed from materials known in the art including , for example , nitrocellulose , poly ( glycidyl methacrylate ), poly ( methyl methacrylate ), poly ( isopropenyl ketone ), and polyester ionomers , as described in u . s . pat . no . 4 , 315 , 978 . the process is useful with planarizing layers , for example , organic planarizing layers , and with some protective overcoats , for example , those formed from poly ( vinyl alcohols ). the process of this invention effectively removes color filter array coatings from any substrate effective for providing a solid - state color image sensing device . examples of suitable substrates include silicon - containing substrates such as monocrystalline silicon , polycrystalline silicon , silicon dioxide , borosilicate , silicon nitride soda - lime , fused silica , spin - on - glass and the like . other useful substrates include gallium arsenide . a substrate which is particularly useful in a solid - state color image sensing device comprises an array of charge - handling semiconductive photosensors and bonding pad areas on a silicon wafer . after the color filter array is formed on the surface of the substrate , electrical contacts are made to the same surface of the substrate through such bonding pad areas . as is well known in the art , the surface of the wafer can also contain other areas such as dicing lines along which the wafer can be cut , areas referred to as guard bands , and so forth . examples of charge - handling semiconductive photosensors include charge - coupled devices ( also known as charge - transfer imagers and the like ), charge - injection devices , bucket brigade devices , diode arrays , combinations of these and the like . useful silicon - containing substrates having photosensitive arrays are described , for example , in u . s . pat . no . 3 , 801 , 884 , and are commercially available . in typical devices of this type , the surface often is coated with a protective layer of sio 2 . in accordance with this invention , a color filter array coating is removed from a device substrate by contacting the coating with dry ozone produced by electric discharge and uv radiation . subsequently , the substrate can be reused to produce another color image sensing device . in a particularly preferred technique for practicing this invention , the stripping process comprises the steps of ( 1 ) heating the color filter array coating while contacting the heated color filter array with dry ozone generated by electrical discharge and from uv lamps for a time sufficient to reduce the photoresist coating to ash , and ( 2 ) subsequently rinsing the substrate with ultrapure water . excellent results have been obtained even with highly crosslinked acrylic coatings by this technique . as noted , the present invention is useful in readily removing coatings in both partly and fully fabricated solid - state color image sensing devices . this is so even when the coating or coatings have been hardened by various bakes and processing steps . for example , during processing , the dyed coating may be hardened by baking at a temperature up to about 200 ° c . for a time up to about one hour . advantageously , the process has been found to be effective in removing coatings that have been dyed with a variety of dyes known to be useful in preparing solid - state color image sensing devices . in a preferred embodiment , the coated substrates are placed in a sealable small oven like chamber having a gas input port and an exhaust port . the wafers typically sit on a tray within the unit . the ozone can be generated in the chamber utilizing a uv source and outside the chamber via electrical discharge and piped in . the chamber has a heat source that may be used as desired during the removal process . there are several commercial units available such as those manufactured by companies such as fusion [ now axcelis technologies , rockville , md . ], samco [ 532 weddell drive , suite 5 , sunnyvale calif . 94089 ], jelight [ 2 mason , irvine calif ., 92618 ], and uvocs [ p . o . box 543 , montgomeryville , pa . 18936 ]. while it is possible to remove conventional coatings using ozone produced by either electric discharge or uv radiation , highly cross linked polymeric coatings can be removed in a reasonable time period only by the simultaneous use of a combination of ozone produced by electric discharge and by uv radiation . ozone is prepared by electrical discharge outside the cleaning chamber and piped into the cleaning chamber . additional ozone is generated within the chamber utilizing a uv radiation source . it is desirable to maintain the temperature in the cleaning chamber at or above ambient temperature . although cleaning will occur at or below ambient temperatures , broadly in the range of from about 0 ° c . to about 300 ° c . for the dry ozone process , it is preferred that the temperature be maintained in the range of from about 150 ° c . to about 300 ° c . and most preferably in the range of from about 230 ° c . to about 300 ° c . as the temperature increases the residence time in the chamber for the cleaning decreases . so , for example , at temperatures at the lower end of the range , a residence time of up to about 2 hours may be necessary . the amount of time required to effect complete removal of the coating depends , of course , on the particular photoresist material to be removed , the coating thickness , the processing steps to which it has been subjected , etc ., and can readily be determined by one of ordinary skill in the art . economic considerations and concerns about degrading the substrate make it desirable to limit the cleaning time . satisfactory results have been obtained with residence times of from about 5 minutes to about 2 hours , preferably from about 5 minutes to about 1 hour and most preferably from about 5 minutes to about 15 minutes . following the ozone treatment step , the substrates are subjected to a wash step in deionized water for a period of from about 5 to about 60 minutes , preferably from about 5 to about 30 minutes and most preferably from about 5 to about 15 minutes . the temperature of the water in the wash bath is in the range of from about 0 ° c . to about 90 ° c ., preferably from about 25 ° c . to about 60 ° c . and most preferably from about 25 ° c . to about 40 ° c . while not essential to achieve the advantageous results , several techniques may be used to enhance the cleaning ability of the wash procedure . the stripping solution can optionally contain additional ingredients , for example , surfactants , wetting agents , stabilizers , etc ., so long as they do not adversely affect the resulting stripped substrate . conventional commercially available cleaning agents or surfactants may be added to the deionized water . suitable examples include alkaline surfactants such as a product sold as microclean ; mixtures of hydrogen peroxide / ammonium hydroxide / water called sc1 clean in semiconductor industry ; deionized water with ammonium hydroxide bubbled through it ; and choline ( organic alkaline )/ surfactant mixtures . in general , most surfactant or alkaline materials will function effectively , either individually or in admixture . the addition of sonic energy during the wash step facilitates cleaning . the amount of sonic power introduced to the system may be in the range of from about 2 to several hundred watts . the sonic energy may be introduced during the complete wash step but is typically introduced during only a portion of the wash step ; in general for from about 2 to about 20 minutes . sonic energy generators are commercially available from suppliers such as branson , verteq [ verteq , inc . 1241 e . dyer rd . suite 100 , santa ana , calif ., usa 92705 ], submicron systems [ now akrion - allentown pa . ], crest or fsi [ fsi international - chaska mn ]. a red - blue - green 3 - color pigmented array using a negative acting photosensitive acrylic polymer produced by fuji photo , inc . was fabricated on a wafer of semiconductor image sensors . the coated substrates were placed on a shelf in the chamber of a samco ozone stripper . the chamber was closed and the substrate heated to a temperature of 230 ° c . ozone produced by electrical discharge by a samco ozone generator at the rate of 25 g / hr was pumped into the chamber . concurrently uv radiation provided by a 235 ( 254 nm & amp ; 183 nm discharge ) watt uv lamp generated ozone in situ . the substrates were maintained in the chamber for a period of 15 minutes at a temperature of 30 ° c ., after which the substrates were removed from the chamber and placed in a wash solution containing deionized , filtered h 2 o containing microclean additive . the solution is agitated during washing by the introduction of sonic energy produced by a branson ultrasonic tank operating at 20 kh . a scanning electron micrograph of the substrate confirmed that all vestiges of the coating had been removed .