WO1992003592A1

WO1992003592A1 - Process and compositions for forming metal oxide layers

Info

Publication number: WO1992003592A1
Application number: PCT/US1991/005718
Authority: WO
Inventors: Charlene Boarts; Rudolf P. Sedlak; Suzette L. Mombrum
Original assignee: Rd Chemical Company
Priority date: 1990-08-14
Filing date: 1991-08-12
Publication date: 1992-03-05
Also published as: AU8532491A

Abstract

Black, brown, and red oxide layers having high adhesion and peel strength are formed on printed circuit boards by adding a suitable amphipathic anionic or amphoteric surfactant to standard oxidizing solutions. The oxide layers thus formed result in multilayer circuit boards having reduced tendency to delaminate.

Description

PROCESS AND COMPOSITIONS FOR FORMING

METAL OXIDE LAYERS

Description

Related Application

This application is a continuation-in-part of copending U.S. Patent Application Serial No. 7/331,262, filed 30 March 1989, incorporated herein by reference.

Technical Field

This invention relates to the chemical processing of printed circuit boards for use in multilayer circuit boards. More specifically, the invention relates to the controlled oxidation of copper circuit paths to enhance interlayer adhesion by forming black, brown, or red oxide layers.

Background of the Invention

Printed circuit boards have long been used in the fabrication of electronic components. Printed circuitry provides a support for discrete components, while providing most of the electrical interconnections between components. The circuitry pattern may be transferred to the board by pnotographic or lithographic techniques, thus permitting mass production without labor-intensive soldering. Circuit boards are generally manufactured from epoxy resin (typically containing reinforcing fiberglass fibers) clad on one or both sides with copper foil. The circuit pattern is applied to one or both sides by marking the pathways with a resist, etching the non-masked copper from the board, and removing the resist.

Single and double sided boards are inherently limited with regard to the density of components they can support and the amount of current they can carry. Printed circuit paths cannot cross, thus requiring careful arrangement of components which may be suboptimum in cases where components may interfere electromagnetically or generate excessive heat. The solution now used is the multilayer circuit board. Several single or double sided circuit boards are prepared, and are laminated together (separated by an appropriate dielectric, typically partially-cured resin) under pressure and heat to form an integral composite board having several layers of circuitry embedded within.

Unfortunately, multilayer boards are prone to delamination and separation. The smooth copper surface of a printed circuit board is not amenable to strong adhesion. It has been suggested that under the heat of the lamination process, amine hydrogen atoms within the resin can reduce oxides and hydroxides on the copper surface to form water, resulting in poor bonding and delamination (K. Nargi, PC Fab (June 1985) 90-95) . The approach used currently is to carefully oxidize the copper paths to form a black oxide, typically using caustic hydroxide/chlorite solutions at elevated temperatures. Modern solutions may also include a phosphate buffer, which will, if the pH is lowered sufficiently, cause formation of a brown or red oxide layer rather than black. Brown or red/brown oxide layers are reported to provide even higher bond strengths than traditional black oxide layers. Properly prepared, black, brown, and red oxide layers improve interlayer adhesion ("peel strength") and reduce delamination. However, oxide formation is a finicky and empirical process. Successful formation of an even, homogeneous layer requires almost surgically clean substrate surfaces. Brown and red oxide layers are even more sensitive to uniformity and cleanliness of the substrate copper, and can be quite troublesome to prepare. The process is sensitive to concentration, temperature, and reaction time. The process must be carefully watched by an experienced technician in order to insure that an even layer of effective thickness is formed. Too much oxide actually decreases adhesion and peel strength. Valayil et al, U.S. Pat. No. 4,512,818 suggested improving the oxidation bath by adding a small amount of a water-soluble polymer such as cellulose, polyvinyl alcohol, polyvinylpyrrolidone, sodium alginate, and the like.

Disclosure of the Invention

We have now invented an improved process for forming black, brown, or red oxide in the fabrication of multilayer circuit boards. The oxide layers of the invention exhibit improved adhesion and peel strength, and result in multilayer boards which are more resistant to delamination. The process of the invention is also advantageous in that reaction time may be accelerated. The oxide layers are formed more evenly, with reduced sensitivity to the cleanliness of the substrate and the reaction time and temperature of the bath. The process comprises forming an oxide layer on a masked circuit board using an oxidizing solution containing an effective amount of an amphipathic anionic or amphoteric surfactant.

Another aspect of the invention is a solution for forming an oxide, comprising an alkali hydroxide, and alkali chlorite, optionally a buffer compound, and an effective amount of amphipathic anionic or amphoteric surfactant.

Modes of Carrying Out The Invention

A. Definitions

The term "amphipathic anionic surfactant" refers to a surface active compound which is anionic in aqueous solution, which displays both hydrophilic regions and hydrophobic regions, and which has a molecular weight of about 180-750 g/mol. These surfactants can provide an actual reduction in surface tension. Amphipathic anionic surfactants within the scope of this invention must be stable to elevated temperatures (135-200°F) , stable under caustic conditions (e.g., 6% chlorite and 4% hydroxide), and must be soluble under process conditions. Presently preferred amphipathic anionic surfactants are di(alkylaryl)oxide disulfonates having alkyl of at least C2, preferably at least C6, and most preferably CIO (for example Dow XD8390, Dowfax® 2A1 and 2A0, or Dowfax® 3B2) , alkylaryl disulfonate salts, particularly alkylnaphthalene disulfonate salts (for example Surfatrope® CF500) , linear alkylsulfonates and alkoxysulfonates having at least seven carbon atoms, preferably having between 3 and 15 ethylene oxide subunits per molecule (for example Avanel® S70 and Avanel® S90) , linear alkylcarboxylate salts of at least CIO (for example Miranate® LEC, Mirawet® B) , and ethoxylated nonylphenol phosphate esters (for example Gafac® RE-610) . Dow XD8390, Dowfax® 2A1 and 2A0 are available commercially from Dow Chemical, Midland, MI. Poly-Tergent® 3B2 is commercially available from Olin Chemicals, Stamford, CT. Avanel® S70 and Avanel® S90 are commercially available from Mazer-PPG, Gurnee, IL. Gafac® RE-610 is commercially available from GAF Chemicals Corp., Wayne, NJ. Surfatrope® CF500 is commercially available from DeSoto, Inc., Fort Worth, TX. Surfactants useful in the present invention are be prepared by methods known in the art, or are obtained from commercial sources.

The term "amphipathic amphoteric surfactant" refers to a surface active compound which has both acidic and basic groups in aqueous solution, which displays both hydrophilic regions and hydrophobic regions, and which has a molecular weight of about 180-750 g/mol.

Amphipathic amphoteric surfactants within the scope of this invention must meet the same stability requirements as amphipathic anionic surfactants, as described above. Presently preferred amphipathic amphoteric surfactants are long-chain derivatives of amino acid salts, such as N-alkyl-b-iminodipropionates, alkyl betaines, caproamphocarboxyglycinates, caproamphoglycinates, and N- alkyl-j8-aminopropionates. Particularly preferred amphipathic amphoterⁱc surfactants are Deriphat® 160C, Deriphat® 160, Deri_t .at® 151C, Velvetex® AB-45, Miranol® S2M, Miranol* CS, and Miranol® SM. Deriphat® 160C, Deriphat® 160, Deriphat® 151C, and Velvetex® AB-45 are commercially available from Henkel Corp. Ambler, PA. Miranol® S2M, Miranol® CS, and Miranol® SM are commercially available from Miranol Chemical Company, Inc. , Dayton, NJ.

The term "effective amount" as used herein refers to the amount of surfactant necessary to improve oxide formation. The effectⁱve amount will vary depending upon the particula surfactant selected and the process conditions employed. The process of the invention is not adversely affected by high concentrations of surfactant, so that higher concentrations may be used if desired. Lower concentrations are preferred due to the expense of using excessive surfactant. In traditional use of surfactants to reduce surface tension, it is found that surface tension decreases logarithmically with increasing surfactant concentration. At the critical micellar concentration or "CMC", the surface tension does not decrease with increasing concentration. The CMC is generally on the order of 0.3 g/L (0.03%) or less for anionic surfactants. Surprisingly, the best effect in the present invention occurs using concentrations of surfactant which are several times higher than the CMC. In general, an effective amount of surfactant will range from about 0.05-10%, preferably from about 0.1-1%, and most preferably about 0.5%.

The terms "alkali metal chlorite" and "alkali metal hydroxide" refer to chlorite and hydroxide salts of lithium, sodium, potassium, and the like. The most commonly employed alkali chlorites and hydroxides are sodium chlorite and sodium hydroxide.

The term "oxide-forming amount" refers to the amount of alkali metal chlorite and alkali metal hydroxide which is capable of forming a black oxide layer on copper or copper alloy printed circuit boards when combined in aqueous solution at 135-200°F, or the amount of alkali metal chlorite, alkali metal hydroxide, and buffer which is capable of forming a brown or red oxide layer under similar conditions. The particular amount of compound employed will vary with the precise conditions and reagents used, but in general ranges from about 20- 150 g/L for sodium chlorite, and about 5-40 g/L for sodium hydroxide.

B. General Method

The compositions of the invention may be provided as solutions, solution concentrates, or in solid

- form (e.g., powders, granulates, pellets, compressed tablets, and the like) . The compositions may be provided as full-strength solutions, or as concentrated solutions or solids for reconstitution by dilution to working strength. Solutions are simply prepared by mixing the appropriate concentrations of components together, with heating if necessary. Concentrated solutions may by saturated or partially saturated solutions, or may be saturated solutions having undissolved solids. Powders may be prepared by mixing the dry chemicals together, by evaporating the solvent from a solution mixture, or other conventional techniques. Full-strength solutions and concentrated solutions are presently preferred for convenience.

In practice, an etched copper-clad board is stripped of resist, carefully cleaned (typically by treatment with an alkaline or acidic cleaning solution. The board is then immersed in an oxidizing bath, usually containing 5-15% chlorite and 2-8% hydroxide, 0.05-10% suitable amphipathic anionic or amphoteric surfactant (preferably from about 0.1-1%, and most prefe: oly about 0.5%), and optionally about 0.1-5% phosphate. The temperature is maintained at a temperature of about 135°F up to the boiling point of the bath formulation, typically at about 185-190°F. The oxidation process is usually complete within 3-5 minutes. However, the process of the invention may be conducted for as little as about 1 minute, and for as long as 10 minutes, and still achieve acceptable results. Brown or red oxide layers are formed by including a sufficient amount of buffer, preferably phosphate, in the bath composition. In contrast, the processes of the prior art require careful attention, and generally do not provide acceptable oxide layers if the reaction time is more than about 30 seconds longer or shorter than the optimum period. The adhesion and resistance to delamination may be tested by preparing multilayer circuit boards and counting the number of failures. However, it is customary in the art to evaluate oxide peel strength by applying a piece of ordinary cellulose adhesive tape

(e.g., Scotch® tape), peeling the tape off in one motion, and examining the tape for the presence of oxide particles. A poor oxide layer will generally leave an easily visible amount of oxide on the tape, and will frequently leave a solid black, brown, or red film. A good oxide layer will leave little or no oxide on the tape. Oxide layers formed with the process of the invention usually do not loose any visible amount of oxide, and frequently retain a portion of the tape adhesive.

C. Examples

The examples presented below are provided as a further guide to the practitioner of ordinary skill in the art, and are not to be construed as limiting the invention in any way.

Example 1 (Preparation of Oxide Layers) (A) A copper clad epoxy board was etched using prior art techniques, as a control for comparison to the process of the invention.

A copper clad laminate of copper foil over epoxy (1.5" x 3") was cleaved by immersion for 2 min at ambient temperature in an acidic preplate cleaner RD-58

Chemprep™ (available from RD Chemical Co., Mountain View, CA) . The plate was then rinsed with water, and immersed in a standard black oxide bath for 3 min at 195°F. Bath A: Sodium chlorite 61.5 g/L Sodium hydroxide 42.4 g/L water qs 1.0 L

Following immersion, the plate was blown dry with nitrogen gas, and inspected. The resulting oxide coating was black and appeared relatively thick.

Adhesion was tested using adhesive tape. A strip of adhesive tape was pressed to the black oxide surface, and pulled off in a single motion. The tape displayed a brown to black film, indicating poor adhesion.

(B) The procedure of part A was repeated, substituting the following bath formula' .on :

Bath B: Sodium chlorite 61.5 g/L

Sodium hydroxide 42.4 g/L Avanel® S90 5.0 g/L water qs 1.0 L

Avanel® S90 is a linear alkyl polyether sulfonate within the scope of the invention (available from PPG Industries, Inc.), and was added as a 35% aqueous solution.

When the plate prepared using this bath formulation was tape-tested, no oxide particles were found adhering to the tape. This demonstrated superior adhesion.

(C) The procedure of part A was repeated, substituting the following bath formulation: Bath C: Sodium chlorite 61.5 g/L

Sodium hydroxide 42.4 g/L Dowfax® 2A1 5.0 g/L water qs 1.0 L

Dowfax® 2A1 is a diphenyl oxide disulfonate within the scope of the invention (available from Dow Chemical Co.), and was added as a 45% aqueous solution. When the plate prepared using this bath formulation was tape-tested, no oxide particles were found adhering to the tape. This demonstrated superior adhesion.

(D) The procedure of part A was repeated, substituting the following bath formulation:

Bath D: Sodium chlorite 20.5 g/L

Sodium hydroxide 42.4 g/L

Gafac® RE-610 3.0 g/L water qs 1.0 L

Gafac® RE-610 is an aromatic phosphate ester surfactant within the scope of the invention (available from GAF Corp.) , and was added neat. When the plate prepared using this bath formulation was tape-tested, no oxide particles were found adhering to the tape. This demonstrated superior adhesion.

(E) The procedure of part A was repeated, substituting the following bath formulation: Bath E: Sodium chlorite 61.5 g/L

Sodium hydroxide 42.4 g/L sodium heptanoate 5.0 g/L water qs 1.0 L

Sodium heptanoate is a linear carboxylic acid outside the scope of this invention. No significant oxide coating was formed.

(F) The procedure of part A was repeated, substituting the following bath formulation:

Bath F: Sodium chlorite 61.5 g/L Sodium hydroxide 42.4 g/L sodium heptanesulfonate 3.0 g/L water qs 1.0 L

Sodium heptanesulfonate is a linear alkyl sulfonate within the scope of the invention (available from Aldrich Chemical Co., Milwaukee, WI) , and was added as a 35% aqueous solution.

(G) The procedure of part A was repeated, substituting the following bath formulation: Bath G: sodium chlorite 61.5 g/L sodium hydroxide 42.4 g/L sodium pentanesulfonate 5.0 g/L water qs 1.0 L

Sodium pentanesulfonate is a linear alkyl sulfonate outside the scope of the invention (available from Aldrich Chemical Co. , Milwaukee, WI) , and was added as a 35% aqueous solution.

When the plate prepared using this bath, oxide formation was inhibited.

(H) The procedure of part A was repeated, substituting the following bath formulation:

Bath H: Sodium chlorite 120.0 g/L

Sodium hydroxide 17.0 g/L

Phosphoric acid 1.0 g/L

Poly-Tergent® 3B2 5.0 g/L water qs 1.0 L

This formulation illustrates a brown oxide forming bath.

Example 2 (Reaction Rate)

(A) The reactions described in Example 1, parts A and B, were conducted simultaneously in side-by-side experiments. Oxide formation was observed during the treatment. Oxide formation in bath A exhibited an apparent lag time, whereas oxide formation in bath B (Avanel® S90) appeared to commence immediately upon immersion. Oxide formation appeared to proceed more rapidly in bath B. Upon simultaneous removal of the plates after 1-2 minutes, a visible difference in coating was apparent. The plate treated in bath B exhibited a blacker, heavier oxide coat.

(B) The reaction described in Example 1, part A was conducted simultaneously in side-by-side experiments using the control bath (Bath A) and the following bath (Bath I) . Oxide formati<_ i was observed during the treatment.

Bath I: Sodium chlorite 61.5 g/L

Sodium hydroxide 42.4 g/L Barlox® 12 3.0 g/L water qs 1.0 L

Barlox® 12 is an amine oxide surfactant (classified as non-ionic/cationic) outside the scope of the invention (available from Lonza Inc. , Long Beach, CA) , and was added as a 30% aqueous solution.

Oxide formation appeared to proceed more slowly in bath I than in bath A (control) .

Example 3 (Red Oxide Formation) Compositions for preparing red oxide layers were tested as set forth below. All panels were prepared by cleaning in alkaline cleaner for 5 min at 140°F. Panels were then etched using an acidic persulfate solution prior to oxidatio.. All oxide-forming solutions were applied at 160°F for 3 min unless otherwise noted. (A) The following bath was prepared for purposes of comparison.

Bath J: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L water qs 1.0 L

Bath J formed a red-brown oxide coating. Oxide formation was fairly rapid, but uneven over the panel surface. When the plate prepared using this bath formulation was tape-tested, some oxide particles were found adhering to the tape. (B)The following bath is within the scope of the invention:

Bath K: Sodium chlorite 150.0 g/L Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L Dowfax® 2A1 10.8 g/L water qs 1.0 L

Bath K formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(C) The following bath is another composition within the scope of the invention:

Bath L: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L Mirawet® B 10.8 g/L water qs 1.0 L Mirawet® B is a commercially available sodium butoxyethoxy acetate surfactant (Miranol Chemical Co.). Bath L formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape- tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(D) The following bath is another composition within the scope of the invention:

Bath M: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Surfatrope® CF500 10.8 g/L water qs 1.0 L

Surfatrope® CF500 is a commercially- -vailable surfactant containing an alkyl naphthalene iisulfonate sodium salt (DeSoto, Inc.). Bath M formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(E) The following bath is another composition within the scope of the invention:

Bath N: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Miranate® LEC 10.8 g/L water qs 1.0 L

Miranate® LEC is a commercially available surfactant containing sodium laureth-13-carboxylate (Miranol Chemical Co. ) . Bath N formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.e

(F) The following bath is another composition within the scope of the invention:

Bath O: Sodium chlorite 150.0 g/L Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Deriphat® 160C 10.8 g/L water qs 1.0 L

Deriphat® 160C is a commercially available surfactant containing monosodium N-lauryl b- iminodipropionic acid, supplied as a 30% solution (Henkel Corp.) . Bath O formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(G) The following bath is another composition within the scope of the invention:

Bath P: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate^' 4.0 g/L

Deriphat® 160 10.8 g/L water qs 1.0 L

Deriphat® 160 is a commercially available surfactant containing disodiu N-lauryl b- iminodipropionic acid, supplied neat (Henkel Corp.). Bath P formed a red-brown oxide coating. Oxide formation -17-

was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape- tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(H) The following bath is another composition within the scope of the invention:

Bath Q: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Velvetex® AB-45 10.8 g/L water qs 1.0 L

Velvetex® AB-45 is a commercially available surfactant containing coco betaine (Henkel Corp.). Bath Q formed a red-brown oxide coating. Oxide formation was fast and even over the entire panel surface. When the plate prepared using this bath formulation was tape- tested, no oxide particles adhered to the tape. Some of the tape adhesive remained on the panel.

(I) The following bath is another composition within the scope of the invention:

Bath R: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Miranol® S2M concentrate 10.8 g/L water qs 1.0 L

Miranol® S2M concent' -ate is a commercially available surfactant contai ng caproamphocarboxyglycinate (Miranol Chemical Co.). Bath R formed a red-brown oι:ide coating. Oxide formation was slow but even over the entire panel surface. When the plate prepared using this bath formulation was tape- tested, no oxide particles adhered to the tape. None of the tape adhesive remained on the panel.

(J) The following bath is another composition within the scope of the invention:

Bath S: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Miranol® CS concentrate 10.8 g/L water qs 1.0 L

Miranol® CS concentrate is a commercially available surfactant containing cocoamphopropylsulfonate (Miranol Chemical Co.). Bath S formed a red-brown oxide coating. Oxide formation was slow but even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. No tape adhesive remained on the panel.

(K) The following bath is another composition within the scope of the invention:

Bath T: Sodium chlorite 150.0 g/L

Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Miranol® SM concentrate 10.8 g/L water qs 1.0 L

Miranol® SM concentrate is a commercially available surfactant containing caproamphoglycinate (Miranol Chemical Co.). Bath T formed a red-brown oxide coating. Oxide formation was slow but even over the entire panel surface. When the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape. No tape adhesive remained on the panel. (L) The following bath is another composition of the invention:

Bath U: Sodium chlorite 150.0 g/L Sodium hydroxide 15.3 g/L trisodium orthophosphate 4.0 g/L

Deriphat® 151C 10.8 g/L water qs 1.0 L

Deriphat® 151C is a commercially available surfactant containing N-coco-/3-aminopropionic acid (Henkel Corp.). Bath T formed a red-brown oxide coating. Oxide formation was slow and uneven over the panel surface, even after 5 min. However, a strong oxide layer was formed: when the plate prepared using this bath formulation was tape-tested, no oxide particles adhered to the tape, and no tape adhesive remained on the panel. (M) Additional bath compositions were prepared using as surfactants the compounds Miranol® HM concentrate (lauroamphoglycinate) , Miranol® J2M concentrate (caprylamphocarboxylate) , and ^iranol JEM concentrate (mixed C8 amphocarboxylates) . However, the solutions became cloudy upon heating to 160°F, indicating that the compositions were unstable and/or insoluble at the operating temperatures. These compositions were not further tested.

Claims

WHAT IS CLAIMED:

1. A composition for forming an oxide coating for multilayer circuit boards, which composition comprises an aqueous solution comprising: an oxide-forming amount of an alkali metal chlorite; an oxide-forming amount of an alkali metal hydroxide; and an effective amount of an amphipathic anionic or amphoteric surfactant.

2. The composition of claim 1 wherein said amphipathic anionic or amphoteric surfactant is a di(alkylaryl)oxide disulfonate having alkyl of at least

C2, an alkylaryl disulfonate salt, an alkali butoxyethoxy acetate salt, or a linear alkylcarboxylate salt of at least CIO.

3. The composition of claim 2 wherein said surfactant is selected from the group consisting of Surfatrope® CF500, Miranate® LEC, and Mirawet® B.

4. The composition of claim 1, wherein said surfactant is an amphipathic amphoteric surfactant selected from the group consisting of N-alkyl-amino acid salts in which alkyl is C7 or greater, N-alkyl-b- iminodipropionate salts, alkyl betaines, caproamphocarboxyglycinates, caproamphoglycinates, and N- alkyl-j8-aminopropionates.

5. The composition of claim 4, wherein said surfactant is selected from the group consisting of Deriphat® 160C, Deriphat® 160, Deriphat® 151C, Velvetex® AB-45, Miranol® S2M, Miranol® CS, and Miranol® SM.

6. The composition of claim 1 wherein said surfactant is present in a concentration of about 0.05% to about 10%.

7. The composition of claim 4 wherein said surfactant is present in a concentration of about 0.1% to about 5%.

8. The composition of claim 5 wherein said surfactant is present in a concentration of about 0.5%.

9. A composition suitable for reconstitution to make an oxide-forming bath for multilayer printed circuit boards, wherein said composition comprises: about 20-250 parts alkali chlorite; about 5-80 parts alkali hydroxide; about 0.5-100 parts amphipathic anionic or amphoteric surfactant; about 0-50 parts phosphate buffer; and about 0-1000 parts water.

10. The composition of claim 9, wherein said surfactant is present in about 1-10 parts.

11. A process for preparing oxide coatings having high peel strength on copper or copper alloy printed circuit boards for multilayer circuit boards, which process comprises: contacting said circuit board with an oxidizir.j composition at a temperature between about 135°F and the boiling point of said oxidizing composition for about 1 to about 10 minutes, wherein said oxidizing composition comprises an oxide-forming amount of an alkali metal chlorite, an oxide-forming amount of an alkali metal hydroxide, an effective amount of an amphipathic anionic or amphoteric surfactant, and a quantity of water sufficient to substantially dissolve said chlorite, hydroxide and surfactant.

12. The process of claim 11 wherein said amphipathic anionic or amphoteric surfactant is a di(alkylaryl)oxide disulfonate having alkyl of at least C2, an alkylaryl disulfonate salt, an alkali butoxyethoxy acetate salt, a linear alkylcarboxylate salt of at least CIO, N-alkyl-amino acid salts in which alkyl is C7 or greater, N-alkyl-b-iminodipropionate salts, alkyl betaines, caproamphocarboxyglycinates, caproamphoglycinates, and N-alkyl-3-aminopropionates.

13. The process of claim 12 wherein said surfactant is selected from the group consisting of Surfatrope® CF500, Miranate® LEC, Mirawet® B, Deriphat® 160C, Deriphat® 160, Deriphat® 151C, Velvetex® AB-45, Miranol® S2M, Miranol® CS, and Miranol® SM.

14. A process for preparing oxide coatings having high peel strength on copper or copper alloy printed circuit boards for multilayer circuit boards, which process comprises: contacting said circuit board with an oxidizing composition at a temperature of about 135°F to the boiling point of said oxidizing composition for about 1 to about 10 minutes, wherein said oxidizing composition comprises about 20-150 parts alkali chlorite, about 5-40 parts alkali hydroxide, about 0.5-100 parts amphipathic anionic or amphoteric surfactant, about 0-50 parts phosphate buffer, and about 1000 parts water.

15. The process of claim 14 wherein said surfactant is present in about 1-10 parts.

16. The process of claim 15 wherein said surfactant is selected from the group consisting of Surfatrope® CF500, Miranate® LEC, Mirawet® B, Deriphat® 160C, Deriphat® 160, Deriphat® 151C, Velvetex® AB-45, Miranol® S2M, Miranol® CS, and Miranol® SM.