Polyimide precursor resin composition for forming flexible device substrate

A method for producing a flexible device substrate, comprising steps of:

• (A) forming a laminate including a carrier substrate and a polyimide film formed thereon, wherein the laminate is formed by casting a polyimide precursor resin composition comprising a polyamic acid on the carrier substrate, and imidizing the polyamic acid by heat treatment to form a polyimide film, wherein
• the polyamic acid has a structure obtained from a tetracarboxylic acid component comprising at least one of 3,3′,4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride;
• a diamine component comprising at least one of paraphenylenediamine and 4,4′-diaminodiphenyl ether;
• and a carboxylic acid monoanhydride;
• wherein the polyamic acid satisfies following equations (1) and (2):
• 0.97≤X/Y<1.00 Equation (1)
• 0.5≤(Z/2)/(Y−X)≤1.05 Equation (2)
• wherein X represents a number of moles of tetracarboxylic acid component, Y represents a number of moles of diamine component, and Z represents a number of moles of the carboxylic acid monoanhydride, wherein a peel strength between the carrier substance and the polyimide film is 300 mN/mm or more;
• (B) forming an inorganic film on the polyimide film;
• and
• (C) separating the polyimide film from the carrier substrate to form a flexible device substrate including the polyimide film,
• wherein the steps are performed in an order of (A), (B), and (C).