Polyimide film, method of manufacture, and metal interconnect board with polyimide film substrate
AssigneeDuPont-Toray Co. Ltd.
InventorsKenji Uhara, Naofumi Yasuda, Kouichi Sawasaki
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Abstract
A polyimide film is manufactured from a random copolymeric, block copolymeric or interpenetrating polymer network-type polyamic acid prepared from pyromellitic dianhydride in combination with 22 to 78 mol % of 4,4′-oxydianiline and 22 to 78 mol % of 3,4′-oxydianiline, based on the overall diamine. The polyimide film, when used as a metal interconnect board substrate in flexible circuits, chip scale packages (CSP), ball grid arrays (BGA) or tape-automated bonding (TAB) tape by providing metal interconnects on the surface thereof, achieves a good balance between a high elastic modulus, a low thermal expansion coefficient, alkali etchability and film formability.
Claims12
A polyimide film manufactured from a polyamic acid prepared from pyromellitic dianhydride in combination with 22 to 78 mol % of 4,4′-oxydianiline and 22 to 78 mol % of 3,4′-oxydianiline, based on the overall diamine and wherein said film has:
- a. a thermal expansion coefficient of 10 to 24.6 ppm/° C.;
- b. an elastic modulus of 3 to 5.5 GPa;
- and c. an elongation of at least 60%.
A polyimide film manufactured from a polyamic acid selected from a block component-containing polyamic acid and an interpenetrating polymer network component-containing polyamic acid, wherein said polyamic acid is prepared from pyromellitic dianhydride in combination with 22 to 78 mol % of 4,4′-oxydianiline and 22 to 78 mol % of 3,4′-oxydianiline, based on the overall diainine and wherein said film has:
- a. a thermal expansion coefficient of 10 to 24.6 ppm/° C.;
- b. an elastic modulus of 3 to 5.5 GPa;
- and c. an elongation of at least 60%.
A method of manufacturing a polyimide film, the method comprising the steps of, in order:
- (A) reacting starting materials comprising (a1) a tetracarboxylic acid dianhydride comprising pyromellitic dianhydride and (a2) a first diamine selected from 4,4′-oxydianiline and 3,4′-oxydianiline, in an inert solvent to form a first polyamic acid solution containing a component selected from a block component of the first diamine and pyromellitic dianhydride and an interpenetrating polymer network component of the first diamine and pyromellitic dianhydride;
- (B) adding to the first polyamic acid prepared in step A additional materials comprising (b1) a tetracarboxylic acid dianhydride comprising pyromellitic dianhydride and (b2) a second diamine selected from 4,4′-oxydianiline and 3,4′-oxydianiline, and continuing the reaction with all the materials to form a second polyamic acid solution;
- (C) mixing into the second polyamic acid solution obtained in step B a chemical agent capable of converting the polyamic acid into polyimide;
- (D) casting or extruding the mixture from step C onto a smooth surface to form a polyamic acid-polyimide gel film;
- (E) heating the gel film at 200 to 500° C. to transform the polyamic acid to polyimide
- wherein at least one of the first diamine and second diamine is a phenylenediamine, and at least one of the first diamine and second diamine is 4,4′-oxydianiline.
Dependencies are inferred from the claim text.