example 1 is dissolved in 4 g of n methylpyrrolidone and the solution is placed in a plastic syringe equipped with a preliminary filter the polymer solution is then applied by means of the syringe to a purified and dried silicon wafer and this is centrifuged in a centrifuge apparatus convac type st 146 drying is then carried out on a hot plate at 115 u00b0 c during which a uniform film is formed on the wafer after cooling the wafer coated with the polymer film is immersed in a commercially available aqueous alkaline developer free of metal ions nmd w 2 38 tokyo ohka during this process the polymer film dissolves uniformly i e without cracking and without flaking off after only a short time the whole polymer film is completely dissolved in the developer the same result is obtained if instead of the above mentioned developer a 3 solution of tetramethylammonium hydroxide in distilled water is used a corresponding solution of the pbo precursor is centrifuged on to a silicon wafer dried at 115 u00b0 c and then annealed in an annealing furnace hs 337 seiter at 350 u00b0 c under nitrogen a uniform highly temperature resistant polybenzoxazole film is formed in this process the following are placed in a 100 ml three necked flask under nitrogen as a protective gas 1 2 g of bis 4 hydroxyphenyl propane 5 4 mmol i e bisphenol a 4 0 g of a dihydroxydiamide 5 4 mmol according to example 1 0 72 g of triethylamine 7 0 mmol and 50 ml of dry dimethylformamide and the mixture is then heated to 80.