Methods of treating metal surfaces and devices formed thereby

Patent metadata

Field	Value
Publication number	US-10375835-B2
Application number	US-201615238881-A
Country	US
Kind code	B2
Filing date	Aug 17, 2016
Priority date	Jul 6, 2009
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

The present invention relates to methods of treating metal surfaces to enhance adhesion or binding to substrates, and devices formed thereby. In some embodiments of the present invention, methods of achieving improved bonding strength without roughening the topography of a metal surface are provided. The metal surface obtained by this method provides strong bonding to resin layers. The bonding interface between the treated metal and the resin layer exhibits resistance to heat, moisture, and chemicals involved in post-lamination process steps, and therefore can suitably be used in the production of PCB's. Methods according to some embodiments of the present invention are especially useful in the fabrication of high density multilayer PCB's, in particular for PCB's having circuits with line/spacing of equal to and less than 10 microns. Methods according to other embodiments of the present invention are particularly useful in the coating of metal surfaces in a wide variety of applications.

First claim

We claim:

1. A method of fabricating a printed circuit board, comprising the steps of:
a. stabilizing a copper surface by forming a copper oxide layer thereon;
b. conditioning the copper oxide layer with a reducing agent, the reducing agent is selected from any one or more of formaldehyde, sodium thiosulfate, sodium borohydride, a borane reducing agent represented by the general formula BH 3 NHRR′, wherein R and R′ are each selected from the group consisting of H, CH 3 and CH 2 CH 3 , dimethylamine borane (DMAB), a cyclic borane, morpholine borane, pyridium borane, and piperidine borane; and
c. coupling one or more organic molecules to the copper oxide layer, the one or more organic molecules comprising a thermally stable base bearing one or more binding groups configured to bind the copper oxide surface and one or more attachment groups configured to attach to a resin,
wherein the stabilizing and the conditioning are carried out so as to not roughen the metal surface relative to the roughness of the metal surface prior to the stabilizing.

2. The method of claim 1 characterized in that the copper surface is pre-cleaned with an alkaline and/or peroxide solution.

3. The method of claim 1 characterized in that the treated copper surface is bonded to the resin.

4. The method of claim 1 characterized in that the formed stabilization layer has a thickness of about 200 nanometers or less.

5. The method of claim 1 characterized in that the stabilization layer has a morphology comprised of a substantially amorphous structure.

6. The method of claim 1 characterized in that the stabilization layer has a highly distributed grain structure, and after conditioning the grains have a size in the range of 200 nanometers or less.

7. The method of claim 1 characterized in that the copper oxide has grains, and after conditioning the grains are substantially randomly oriented.

8. The method of claim 1 characterized in that the stabilizing the copper surface by forming a copper oxide is by exposing the copper surface to an oxidant selected from sodium chlorite, hydrogen peroxide, permanganate, perchlorate, persulphate, ozone or mixtures thereof.

9. The method of claim 1 characterized in that the step of stabilizing the metal surface may be carried out at a temperature in the range of room temperature to about 80° C.

10. The method of claim 1 characterized in that the conditioning of the copper oxide layer is carried out at a temperature in the range of room temperature to about 50° C.

11. The method of claim 1 characterized in that the entire method is carried out for a time in the range of about 2 to 20 minutes.

12. The method of claim 1 characterized in that the one or more organic molecules is selected from a porphyrin, a porphyrinic macrocycle, an expanded porphyrin, a contracted porphyrin, a linear porphyrin polymer, a porphyrinic sandwich coordination complex, or a porphyrin array.

13. The method of claim 1 characterized in that the at least one attachment group comprises an alcohol or a phosphonate.

14. The method of claim 1 characterized in that the at least one attachment group comprises any one of more of: amines, alcohols, ethers, other nucleophile, phenyl ethynes, phenyl allylic groups, phosphonates and combinations thereof.

15. The method of claim 1 characterized in that the one or more organic molecules is a surface modifier moiety.

16. The method of claim 15 characterized in that the surface modifier moiety is selected from the group consisting of a macrocyclic proligand, a macrocyclic complex, a sandwich coordination complex and polymers thereof.

17. The method of claim 15 characterized in that the surface modifier moiety is comprised of a porphyrin.

18. The method of claim 15 characterized in that the one or more surface modifier moieties is selected from a porphyrin, a porphyrinic macrocycle, an expanded porphyrin, a contracted porphyrin, a linear porphyrin polymer, a porphyrinic sandwich coordination complex, a porphyrin array, a silane, a tetraorgano-silane, aminoethyl-aminopropyl-trimethoxysilane, (3-Aminopropyl)trimethoxysilane, (I-[3-(Trimethoxysilyl)propyl]urea), (3-Aminopropyl) triethoxysilane, ((3-Glycidyloxypropyl)trimethoxysilane), (3-Chloropropyl) trimethoxysilane, (3-Glycidyloxypropyl)trimethoxysilane, Dimethyldichlorosilane, 3-(Trimethoxysilyl)propyl methacrylate, Ethyltriacetoxysilane, Triethoxy(isobutyl)silane, Triethoxy(octyl) silane, Tris(2-methoxyethoxy)(vinyl)silane, Chlorotrimethylsilane, Methyltrichlorosilane, Silicon tetrachloride, Tetraethoxysilane, Phenyltrimethoxysilane, Chlorotriethoxysilane, ethylene-trimethoxysilane, an amine, a sugar or any combination of the above.

19. The method of claim 15 characterized in that the one or more surface modifier moieties is selected from the group consisting of molybdates, tungstates, tantalates, niobates, vanadates, isopoly or heteropoly acids of molybdenum, tungsten, tantalum, niobium, vanadium, and combinations of any of the foregoing.

20. The method of claim 1 characterized in that the one or more attachment group is comprised of an aryl functional group and/or an alkyl attachment group.

21. The method of claim 20 characterized in that the aryl functional group is comprised of a functional group selected from acetate, alkylamino, allyl, amine, amino, bromo, bromomethyl, carbonyl, carboxylate, carboxylic acid, dihydroxyphosphoryl, epoxide, ester, ether, ethynyl, formyl, hydroxy, hydroxymethyl, iodo, mercapto, mercaptomethyl, Se-acetylseleno, Se-acetylselenomethyl, S-acetylthio, S-acetylthiomethyl, selenyl, 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl, 2-(trimethylsilyl)ethynyl, vinyl, and combinations thereof.

22. The method of claim 20 characterized in that the alkyl attachment group comprises a functional group selected from acetate, alkylamino, allyl, amine, amino, bromo, bromomethyl, carbonyl, carboxylate, carboxylic acid, dihydroxyphosphoryl, epoxide, ester, ether, ethynyl, formyl, hydroxy, hydroxymethyl, iodo, mercapto, mercaptomethyl, Se-acetylseleno, Se-acetylselenomethyl, S-acetylthio, S-acetylthiomethyl, selenyl, 4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl, 2-(trimethylsilyl)ethynyl, vinyl, and combinations thereof.

Assignees

• Atotech Deutschland Gmbh
• Atotech Deutchland Gmbh

Inventors

• Wei Jen-Chieh
• Liu Zhiming
• Shi Steven Z
• Kuhr Werner G

Classifications

• C23C8/40

  using liquids, e.g. salt baths, liquid suspensions · CPC title

• C09J5/02 Primary

  involving pretreatment of the surfaces to be joined · CPC title

• C09J2400/166

  in the pretreated surface to be joined · CPC title

• H05K3/385 Primary

  by conversion of the surface of the metal, e.g. by oxidation, whether or not followed by reaction or removal of the converted layer · CPC title

• C23C22/63

  Treatment of copper or alloys based thereon · CPC title