Multilayer carrier foil

Patent metadata

Field	Value
Publication number	US-9955588-B1
Application number	US-201615361983-A
Country	US
Kind code	B1
Filing date	Nov 28, 2016
Priority date	Nov 28, 2016
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

The present disclosure relates to a multilayer carrier foil, a core structure formed using the multilayer carrier foil, printed circuit boards, and electronic devices. The multilayer carrier foil comprises: (a) a copper carrier layer having a release side and a laminate side, the laminate side of carrier layer optionally having nodules; (b) a chromium release layer applied to the copper carrier layer; (c) an intermediate copper layer applied to the chromium release layer; (d) an anti-migration layer applied to the intermediate copper layer of (c); and (e) an ultra-thin copper layer applied to the anti-migration layer of (d). The disclosure further relates to methods of making the multi-layer carrier foil, the core structure, and printed circuit boards.

First claim

The invention claimed is:

1. A multilayer carrier foil comprising:
(a) a copper carrier layer having a release side and a laminate side, the laminate side of copper carrier layer optionally having nodules;
(b) a chromium release layer applied to the release side of the copper carrier layer of (a);
(c) an intermediate copper layer applied to the chromium release layer of (b);
(d) an anti-migration layer applied to the intermediate copper layer of (c);
(e) an ultra-thin copper layer directly applied to the anti-migration layer of (d);
wherein the anti-migration layer (d) has a thickness of 0.5 μm to 3 μm.

2. A multilayer carrier foil comprising:
(a) a copper carrier layer having a release side and a laminate side, the laminate side of carrier layer optionally having nodules;
(b) a chromium release layer applied to the release side of the copper carrier layer of (a);
(c) an intermediate copper layer applied to the chromium release layer of (b);
(d) an anti-migration layer applied to the intermediate copper layer of (c); and,
(e) an ultra-thin copper layer applied to the anti-migration layer of (d);
wherein the chromium release layer of (b) has chromium content of 10 μg/dm 2 to 40 μg/dm 2 .

3. The multilayer carrier foil of claim 1 , wherein the anti-migration layer of (d) is a nickel layer.

4. The multilayer carrier foil of claim 1 , wherein the ultra-thin copper layer of (e) has a thickness of 1 μm to 8 μm.

5. The multilayer carrier foil of claim 1 , wherein the ultra-thin copper layer of (e) has a thickness of 1 μm to 5 μm.

6. The multilayer carrier foil of claim 1 , wherein the copper carrier layer of (a) has a thickness of 10 μm to 50 μm.

7. The multilayer carrier foil of claim 1 , further comprising an anti-tarnish layer on an exposed surface of the ultra-thin copper layer and/or on an exposed surface of the laminate side of the copper carrier layer.

8. The multilayer carrier foil of claim 7 , wherein the anti-tarnish layer comprises chromium.

9. A core structure comprising an inner substrate layer sandwiched between two sheets of a multilayer carrier foil of claim 1 , wherein both sides of the inner substrate layer attach to the laminate side of both sheets of the copper carrier foil.

10. The core structure of claim 9 , wherein the inner substrate layer comprises a phenolic resin, an epoxy, a bismaleimide triazine, a polyimide, a liquid crystal polymer, a polyphenylene oxide, a polyphenylene ether, a polytetrafluoroethylene, a cyanate ester, and a mixture thereof.

11. A method for manufacturing a multilayer carrier foil of claim 1 comprising:
(a) forming a copper carrier layer having a release side and a laminate side, the laminate side of copper carrier layer optionally having nodules;
(b) forming a chromium release layer on the release side of the copper carrier layer of (a);
(c) forming an intermediate copper layer on the chromium release layer of (b);
(d) forming an anti-migration layer on the intermediate copper layer of (c);
(e) forming an ultra-thin copper layer directly on the anti-migration layer of (d);
wherein the anti-migration layer (d) has a thickness of 0.5 μm to 3 μm.

12. A method for manufacturing a printed circuit board comprising:
i. obtaining a multilayer carrier foil of claim 1 ;
ii. forming a core structure comprising an inner substrate layer sandwiched between sheets of the multilayer carrier foil, wherein both sides of the inner substrate layer attach to the laminate side of a sheet of the copper carrier foil;
iii. patterning an exposed surface of the ultra-thin copper layers;
iv. applying an outer substrate layer to the patterned ultra-thin copper layers;
v. obtaining a conventional carrier foil comprising:
(A) a conventional copper carrier layer;
(B) a conventional chromium or organic release layer applied to the conventional copper carrier layer of (A); and
(C) a conventional ultra-thin copper layer applied to the conventional chromium or organic release layer of (B); and applying the conventional ultra-thin copper layer of the conventional carrier foil to the outer substrate layer of (iv);

vi. removing the conventional copper carrier layers and the conventional chromium or organic release layers from the conventional ultra-thin copper layers;
vii. forming openings through the conventional ultra-thin copper layers and the outer substrate layers;
viii. filing the openings with a conductive material and optionally patterning an exposed surface of the conventional ultra-thin copper layers and/or an exposed surface of the filled openings of (viii);
ix. separating the patterned conventional ultra-thin copper layers, which are attached to the outer substrates, which are attached to the anti-migration layers, which are attached to the intermediate copper layers from the chromium release layers;
x. removing the intermediate copper layers, the anti-migration layers, and the ultra-thin copper layers to form a remaining patterned outer substrate layer; and
xi. bonding the remaining patterned outer substrate layer to an electronic device.

13. The method of claim 12 , wherein patterning an exposed surface of the ultra-thin copper layers in (iii) or patterning an exposed surface of the conventional ultra-thin copper layers and/or an exposed surface of the filled openings of (viii) in (xiii) comprises applying a patterned photoresist layer to the exposed surface and patterning the exposed surface with a conductive material by plating or etching, and removing the patterned photoresist layers.

14. The method of claim 13 , wherein the conductive material comprises copper.

15. The method of claim 14 , wherein the outer substrate layer of (iv) comprises a phenolic resin, an epoxy, a bismaleimide triazine, a polyimide, a liquid crystal polymer, a polyphenylene oxide, a polyphenylene ether, a polytetrafluoroethylene, a cyanate ester, and a mixture thereof.

16. The method of claim 12 , wherein forming openings through the conventional ultra-thin copper layers is carried out with a laser.

17. A printed circuit board made by the method of claim 12 .

18. An electronic device comprising the printed circuit board of claim 17 .

19. The multilayer carrier foil of claim 1 , wherein the intermediate copper layer (c) has a thickness of 0.5 μm to 5 μm.

Assignees

• Chang Chun Petrochemical Co Ltd

Inventors

• Lai Yao-Sheng
• Cheng Kuei-Sen
• Chou Jui-Chang

Classifications

• H05K2201/0355

  Metal foils · CPC title

• H05K3/007

  Manufacture or processing of a substrate for a printed circuit board supported by a temporary or sacrificial carrier (H05K1/187, H05K3/20 and H05K3/4682 take precedence) · CPC title

• H05K3/421

  Blind plated via connections (H05K3/422, H05K3/423 and H05K3/425 take precedence) · CPC title

• H05K2203/0502

  Patterning and lithography · CPC title

• H05K3/022

  Processes for manufacturing precursors of printed circuits, i.e. copper-clad substrates · CPC title