Metal foil laminated polyimide resin substrate

1. A laminate comprising an adhesive organic material layer and a sol imide resin substrate wherein the adhesive organic material layer is laminated on a surface of the polyimide resin substrate which is exposed by removing at least a portion of a metal foil of a metal foil laminated polyimide resin substrate wherein

the metal foil is directly laminated on the polyimide resin substrate; and

the surface of the metal foil to be bonded to the polyimide resin substrate has:

a surface roughness (Rzjis) of 3.0 μm or less;

a surface area ratio (B) of 1.25 to 2.50, in which the surface area ratio (B) is calculated as a ratio [A/6550] of a surface area of a two-dimensional region with a surface area of 6550 μm 2 which is determined by a laser method (three-dimensional area: A μm 2 ) to the area of the two-dimensional region; and

a chromium content per unit area of the two-dimensional region of 2.0 mg/m 2 or more, and roughening particles are formed on the surface of the metal foil to be bonded to the polyimide resin substrate.

2. The laminate as claimed in claim 1 , wherein

the metal foil has a roughened surface to be bonded to the polyimide resin substrate,

the metal foil is produced by roughening a surface of a untreated metal foil to be bonded to the polyimide resin substrate, which has a surface roughness (Rzjis) of less than 1.0 μm before surface roughening, and

a ratio [b/a] of the surface area after surface roughening (three-dimensional area: b μm 2 ) to the surface area before surface roughening (three-dimensional area: a μm 2 ) of a two-dimensional region with a surface area of 6550 μm 2 which is determined by a laser method is in the range of 1.20 to 2.50.

3. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate comprises a nickel-zinc alloy layer in an amount of 40 mg/m 2 or more per unit area of the two-dimensional region.

4. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate has an L value of from 47 to 63 in the Lab color coordinate system.

5. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate has a surface area ratio (B) of 1.60 to 2.50, in which the surface area ratio (B) is calculated as a ratio [A/6550] of a surface area of a two-dimensional region with a surface area of 6550 μm 2 which is determined by a laser method (three-dimensional area: A μm 2 ) to the area of the two-dimensional region.

6. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate has a surface roughness (Rzjis) of 2.5 μm or less.

7. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate has a surface roughness (Rzjis) of 2.5 μm or less; and a surface area ratio (B) of 1.60 to 2.50, in which the surface area ratio (B) is calculated as a ratio [A/6550] of a surface area of a two-dimensional region with a surface area of 6550 μm 2 which is determined by a laser method (three-dimensional area: A μm 2 ) to the area of the two-dimensional region.

8. The laminate as claimed in claim 1 , wherein the surface of the metal foil to be bonded to the polyimide resin substrate has a coupling agent layer.

9. The laminate as claimed in claim 1 , wherein the metal foil is an electrolytic copper foil.

10. The laminate as claimed in claim 1 , wherein the polyimide resin substrate comprises a heat-resistant polyimide layer and a thermocompression-bondable polyimide layer, which is laminated on at least one side of the heat-resistant polyimide layer; and the metal foil is laminated on the thermocompression-bondable polyimide layer.

11. The laminate as claimed in claim 1 , wherein the polyimide resin substrate has a thermocompression-bondable surface to be bonded to the metal foil; and

the metal foil is bonded to the thermocompression-bondable surface of the polyimide resin substrate using a hot-press forming machine.

12. The laminate as claimed in claim 11 , wherein a thickness of the thermocompression-bondable layer of the polyimide resin substrate to be bonded to the metal foil is equal to or greater than a surface roughness (Rzjis) of the surface of the metal foil to be bonded to the polyimide resin substrate.

13. The laminate as claimed in claim 11 , wherein a thickness of the thermocompression-bondable layer of the polyimide resin substrate to be bonded to the metal foil is equal to or greater than a surface roughness (Rzjis) of the surface of the metal foil to be bonded to the polyimide resin substrate, and is less than or equal to 3 μm.

14. A wiring board comprising the laminate as claimed in claim 1 , wherein a metal wiring is formed by etching the metal foil of the metal foil laminated polyimide resin substrate.

15. The wiring board as claimed in claim 14 , wherein the adhesive organic material layer is laminated on the metal wiring side.

16. The wiring board as claimed in claim 15 , wherein the adhesive organic material layer comprises epoxy.

17. A process for producing a laminate as claimed in claim 1 , comprising bonding a surface of a metal foil to a thermocompression bondable surface of a polyimide resin substrate using a hot-press forming machine to form a metal foil laminated polyimide resin substrate, wherein the metal foil has the following properties:

a surface roughness (Rzjis) is 3.0 μm or less;

a surface area ratio (B) is 1.25 to 2.50, in which the surface area ratio (B) is calculated as a ratio [A/6550] of a surface area of a two-dimensional region with a surface area of 6550 μm 2 which is determined by a laser method (three-dimensional area: A μm 2 ) to the area of the two-dimensional region; and

a chromium content per unit area of the two-dimensional region is at least 2.0 mg/m 2 ;

removing at least a portion of the metal foil of the metal foil laminated polyimide resin substrate; and

laminating an adhesive organic material layer on at least a portion of the exposed surface of the polyimide resin substrate.

18. The laminate as claimed in claim 1 , wherein the roughening particles have a substantially spherical shape.