A material comprising a specific bisphenol compound of formula (1) is useful in forming a photoresist undercoat wherein R.sup.1 and R.sup.2 are H, alkyl, aryl or alkenyl, R.sup.3 and R.sup.4 are H, alkyl, alkenyl, aryl, acetal, acyl or glycidyl, R.sup.5 and R.sup.6 are alkyl having a ring structure, or R.sup.5 and R.sup.6 bond together to form a ring. The undercoat-forming material has an extinction coefficient sufficient to provide an antireflective effect at a thickness of at least 200 nm, and a high etching resistance as demonstrated by slow etching rates with CF.sub.4/CHF.sub.3 and Cl.sub.2/BCl.sub.3 gases for substrate processing. ##STR00001##