| 摘要 |
PURPOSE:To enhance the cleaning effect of the photo mask and achieve the increase in the number of use times by covering the surface for forming photo mask patterns with the coating film of silicon oxide and using the mask. CONSTITUTION:A coating film 3 of silicon oxide is provided over the entire surface of a glass substrate 1 formed with mask patterns 2. The above-mentioned film 3 is formed as a transparent film of thicknesses 0.1-0.2mu by coating the liquid-form one normally called ''silica film'' (e.g., O.C.D. made by Tokyo Oka Kogyo K.K.). When stains have deposited on the mask surface through the use of the above- mentioned mask and repetition of photo resist pattern formation on semiconductor device substrates, the photo mask is cleaned with, e.g., a dilute hydrofluoric acid solution to etch away the above-mentioned silicon oxide film and also strip away the stains, thence the coating film of the silicon oxide is again deposited, thus it is used as the mask of a clean pattern surface. |
