| 摘要 |
PURPOSE:To obtain a resist film having excellent resolution, acid resistance, adhesion to a metal thin plate and mechanical strength without using chromium salt which is harmful for a human body by using aldehydes and metal salt for a hardening liquid. CONSTITUTION:After a photoresist film essentially comprising casein formed on a metal thin plate is exposed and developed, the metal plate is dipped in a hardening liquid and subjected to burning treatment to harden the water-soluble photoresist film. The hardening liquid used contains at least aldehydes and metal salt. Besides, the hardening liquid contains acid to have pH>=3 and contains two or more kinds of metal salts. The aldehydes and metal salts are not specified, but glutaraldehyde and Ca ion are preferable. |
