WO2015023295A1 - Adhesion promotion in printed circuit boards - Google Patents
Adhesion promotion in printed circuit boards Download PDFInfo
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- WO2015023295A1 WO2015023295A1 PCT/US2013/055368 US2013055368W WO2015023295A1 WO 2015023295 A1 WO2015023295 A1 WO 2015023295A1 US 2013055368 W US2013055368 W US 2013055368W WO 2015023295 A1 WO2015023295 A1 WO 2015023295A1
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- substituted
- unsubstituted
- set forth
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- copper
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- 0 CC1C(*)CCC1 Chemical compound CC1C(*)CCC1 0.000 description 9
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
- H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
- H05K3/383—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal by microetching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/18—Acidic compositions for etching copper or alloys thereof
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
- H05K3/389—Improvement of the adhesion between the insulating substrate and the metal by the use of a coupling agent, e.g. silane
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/03—Metal processing
- H05K2203/0392—Pretreatment of metal, e.g. before finish plating, etching
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
- H05K2203/0779—Treatments involving liquids, e.g. plating, rinsing characterised by the specific liquids involved
- H05K2203/0786—Using an aqueous solution, e.g. for cleaning or during drilling of holes
- H05K2203/0793—Aqueous alkaline solution, e.g. for cleaning or etching
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/12—Using specific substances
- H05K2203/122—Organic non-polymeric compounds, e.g. oil, wax, thiol
- H05K2203/124—Heterocyclic organic compounds, e.g. azole, furan
Definitions
- This invention relates to improving adhesion of metal surfaces, such as copper to an insulating layer, in the manufacture of printed circuit boards.
- a multilayer circuit board has, among other things, a number of metal layers defining circuit patterns, and a number of insulating layers there-between .
- the metal layers defining circuit patterns today are typically formed from copper, and the insulating layers are typically formed from a resinous fiber-impregnated dielectric material.
- respective layers can have a wide variety of thickness. For example, they can be on the order of only microns thick, or much thicker .
- organometallic conversion coating processes which produce significantly lighter coatings are generally
- the application is directed to a method for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board, the method comprising contacting the copper conducting layer with a conditioning composition, said
- conditioning composition comprising a functional organic compound and a transition metal ion, said functional organic compound being capable of forming a self-assembled monolayer on a copper surface, and thereafter contacting the copper
- an adhesion promoting composition that comprises an oxidizing agent, an inorganic acid, and a corrosion inhibitor .
- the invention is directed to a method for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board, the method comprising contacting the copper conducting layer with a conditioning composition comprising an organic N-bearing compound capable of forming a self-assembled monolayer on a copper surface, and thereafter contacting the copper conducting layer with an adhesion promoting composition that comprises an oxidizing agent, an inorganic acid, a corrosion inhibitor and a transition metal ion selected from the group consisting of zinc, nickel, cobalt, copper, silver, gold, palladium and other platinum group metals, said corrosion inhibitor comprising an aromatic heterocyclic compound
- the invention is further directed to an aqueous alkaline composition comprising a nitrogen-containing aromatic heterocyclic compound and a transition metal ion, said
- heterocyclic compound comprising a ring group or an amine substitutent on the ring wherein R7 is hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, or a negative charge, said heterocyclic compound being capable of forming a self-assembled monolayer on a copper surface .
- the invention is also directed to an aqueous composition for treating a copper surface to enhance adhesion to a dielectric, the composition comprising between about 0.02 and about 2 wt . % transition metal ion selected from the group consisting of zinc, nickel, cobalt, copper, silver, gold, palladium and other platinum group metal, between about 10 and about 50 wt . % sulfuric acid, between about 1 and about 10 wt . % hydrogen peroxide, and a corrosion inhibitor comprising a nitrogen-containing aromatic heterocyclic compound.
- transition metal ion selected from the group consisting of zinc, nickel, cobalt, copper, silver, gold, palladium and other platinum group metal
- between about 10 and about 50 wt . % sulfuric acid between about 1 and about 10 wt . % hydrogen peroxide
- a corrosion inhibitor comprising a nitrogen-containing aromatic heterocyclic compound.
- the invention is directed to method for enhancing adhesion between a copper conducting layer and a dielectric material during manufacture of a printed circuit board.
- the method comprises contacting the copper conducting layer with a conditioning composition comprising a nitrogen-containing aromatic heterocyclic compound that is capable of forming a self-assembled monolayer on a copper surface.
- the nitrogen-containing aromatic heterocyclic compound corresponds to the formula:
- R 2 , R 6 , and R 8 is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted
- hydrocarbyl, hydroxycarbonyl , alkoxycarbonyl , alkoxy, hydroxyl, sulfhydryl, halo, nitro, cyano and NR 9 R 10 , R 7 is selected from the group consisting of hydrogen, hydrocarbyl, substituted
- each of R 9 and R 10 is independently selected from the group consisting of hydrogen, hydrocarbyl and substituted hydrocarbyl.
- the invention is still further directed to method for preparing a copper conducting layer for adhesion to a dielectric material during manufacture of a printed circuit board.
- the method comprises contacting the copper conducting layer with a conditioning composition comprising a nitrogen- containing aromatic heterocyclic compound and an anionic
- the nitrogen-containing aromatic heterocyclic compound is capable of forming a self-assembled monolayer on a
- the copper surface and comprises a ring ⁇ group or an amine substitutent on the ring wherein R 7 is hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, or a negative charge.
- an adhesive promoting composition that comprises an acid and an oxidant .
- the invention is also directed to a method for preparing a copper conducting layer for adhesion to a dielectric material during manufacture of a printed circuit board.
- the method comprises contacting the copper conducting layer with a conditioning composition comprising a nitrogen-containing aromatic heterocyclic compound, an alkali metal iodide and a glycol ether.
- the nitrogen containing heterocyclic compound is capable of forming a self-assembled monolayer on a copper
- R 7 is hydrogen, hydrocarbyl, substituted hydrocarbyl, hydroxyl, or a negative charge.
- Fig. 1 is a series of bar graphs showing peel strength as a function of copper loading for various laminates prepared at 15.5 bars after treatment with a conditioner and adhesion promoter of the invention as described in Example 18, wherein each of the conditioner and adhesion promoter
- compositions contained a concentration of copper ion ranging from 0 to 10 g/1,
- Fig. 2 is a series of bar graphs showing peel strength as a function of copper loading for laminates prepared at 24.1 bars after treatment with a conditioner and adhesion promoter of the invention as further described in Example 18, wherein again each of the conditioner and adhesion promoter compositions contained a concentration of copper ion ranging from 0 to 10 g/1; [ 0015 ] Each of Figs.
- 3 to 6 is a series of bar graphs showing peel strength as a function of copper loading for laminates prepared after treatment with a conditioner and adhesion promoter at two different laminating pressures (24.1 bars or 15.5 bars) and both before and after reflow, as further described in Example 19, wherein again each of the conditioner and adhesion promoter compositions contained a concentration of copper ion ranging from 0 to 10 g/l;
- FIG. 7 and 8 is a series of bar graphs showing peel strength as a function of copper loading for laminates prepared at 15.5 bars and 24.1 bars, respectively, after treatment with a conditioner and adhesion promoter as described in Example 20, wherein each of the conditioner and adhesion promoting composition had a copper ion content ranging from 0 to 10 g/l and the adhesion promoting composition had not been doped with the conditioner;
- FIG. 9 and 10 are a series of bar graphs showing peel strength as a function of copper loading for laminates prepared at 15.5 and 24.1 bars, respectively, after treatment with a conditioner and adhesion promoter as described in Example 20, wherein each of the conditioner and adhesion promoting composition had a copper ion content ranging from 0 to 10 g/l and the adhesion promoting composition had been doped with ⁇ 1 g/l of conditioner #2;
- Fig. 11 is a series of bar graphs showing peel strength as a function of conditioner #2 content in the adhesion promoting composition for laminates prepared according to
- compositions had a copper ion content of approximately 5 g/l;
- Fig. 12 is a series of bar graphs showing peel strength as a function of copper loading for laminates prepared according to Example 22 wherein the copper ion concentration ranged from 0 to 50 g/1 and no Conditioner #2 was added to the adhesion promoting composition;
- Fig. 13 is a series of bar graphs showing peel strength as a function of copper loading for laminates prepared according to Example 22 wherein the copper ion concentration ranged from 0 to 50 g/1 and the adhesion promoting composition was doped with ⁇ 1 g/1 Conditioner #2;
- Fig. 14 is a series of bar graphs showing peel strength as a function of dwell time between application of the conditioner and application of the adhesion promoting
- FIG. 15 and 16 is a series of bar graphs showing peel strength as a function of conditioner #2 content in the adhesion promoting composition for laminates prepared according to Example 24 wherein each of the conditioner and adhesion promoting compositions had a copper ion content of approximately 10 g/1.
- the present invention is directed to compositions and methods for enhancing adhesion between a copper conducting layer and a non-conducting laminate.
- compositions and methods for enhancing adhesion between a copper conducting layer and a non-conducting laminate As a general proposition, the development of an adhesive organometallic conversion coating on the surface of the copper conducting layer occurs by
- cuprous ions Cu +
- cupric ions Cu 2+
- the cuprous ions on the surface bind with a corrosion inhibitor in the adhesion promotion composition and form a copper-inhibitor-complex as copper dissolves from the conducting copper layer into the adhesion promoter chemistry at the same time. This results in micro-roughened surface morphology of the conducting copper layer. This micro-roughened copper surface promotes adhesion with the subsequently applied insulating layer.
- the copper conducting layer is preferabl contacted with a conditioning composition comprising a nitrogen containing heterocycle that is capable of forming a self- assembled monolayer (SAM) on a copper surface.
- a conditioning composition comprising a nitrogen containing heterocycle that is capable of forming a self- assembled monolayer (SAM) on a copper surface.
- SAM self- assembled monolayer
- the self-assembled monolayer essentially consists of a densely packed organic film formed of a monolayer of the nitrogen-containing heterocycle molecule or other film-forming organic nitrogen or sulfur compound
- the self assembled monolayer formed over the copper surface from the conditioning solution functions to passivate the copper surface by blocking access of oxygen contained in the adhesion promoting
- composition modulates the effect of the subsequently applied adhesion promotion solution by preventing excess copper oxide formation that may otherwise result from the aggressive effect of the peroxide component of the latter solution.
- the conditioning composition preferably contains a transition metal ion, typically in the form of a transition metal salt.
- transition metal ions include zinc, nickel, copper, cobalt, silver, gold, palladium and other platinum group metals
- the transition metal ion is selected from the group consisting of zinc, nickel, cobalt, silver, gold, palladium and other platinum group metals, more preferably zinc, nickel, cobalt or silver, still more preferably zinc, nickel or cobalt.
- Zinc is preferred.
- Various salts of the transition metal can be used, including sulfates, chlorides, other halides, most
- transition metal ions in the conditioning solution contributes to the heat stability of the conversion coating produced in the subsequent treatment with the adhesion promoting solution.
- zinc is incorporated into the conditioning solution in the form of an alkaline dispersion of ZnO, a solution of alkali metal zincate, or a zinc ammonium halide such as zinc ammonium chloride.
- the nitrogen-containing heterocycle is a purine compound, for example, a compound that corresponds to the formula :
- R 2 , R 6 , and R 8 is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted
- hydrocarbyl, hydroxycarbonyl , alkoxycarbonyl , alkoxy, hydroxyl, sulfhydryl, halo, nitro, cyano and NR 9 R 10 , R 7 is selected from the group consisting of hydrogen, hydrocarbyl, substituted
- each of R 9 and R 10 is independently selected from the group consisting of hydrogen, hydrocarbyl and substituted hydrocarbyl.
- each of R 9 and R 10 is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aralkyl and aryl .
- R 6 of Formula I comprises NR 9 R 10 .
- the hydrocarbyl substituent is
- the substituent on the hydrocarbyl is preferably amino, cyano, nitro, halo, hydroxy or sulfhydryl.
- R 9 is hydrogen and R 10 is benzyl, i.e., the compound forming the self-assembling monolayer is most preferably an amino substituted purine such as 6-benz laminopurine :
- the compound of Formula I can also advantageously comprise unsubstituted purine.
- R 7 is preferably hydrogen and said
- R 7 comprises hydrox or a negative charge.
- Purine derivatives have further been found to contribute to the thermal stability of the conversion coating produced by subsequent treatment with the adhesion promoting solution .
- Benzo-triazole BTA and various substituted benzotriazoles , as well as substituted and unsubstituted triazoles, tetrazoles, benzimidazoles , etc.
- the heterocycle may comprise a functional ring substituent such as thiol, vinyl ether, thiamide, amine, carboxylic acid, ester, alcohol, silane, alkoxy silane.
- exemplary compounds useful in forming the self assembled monolayer include adenine, 2-mercaptobenzimidazole,
- the self-assembling monolayer can be formed from: arylamines such as aniline, aniline derivatives, toluidine and toluidine derivatives; aralkylamines such as benzylamine, tolylamine and benzylamine and tolylamine derivatives; various alkylamines , particularly fatty amines; sulfur-bearing aromatic heterocyclic compounds such as thiophene, thiophene derivatives,
- benzothiophene benzothiophene , benzothiophene derivatives, benzothiazoles and benzothiazole derivatives; aryl thiols such as thiophenol, thiophenol derivatives, tolyl thiol and tolyl thiol derivatives; and other aralkyl thiols such as benzyl mercaptan and
- suitable components from which the self-assembling monolayer can be formed include multi-functional compounds having structure (la) or structure (lb) :
- Ai, A 2 , A3, A 4 , A 5 , A 6 , and A 7 are carbon atoms or nitrogen atoms and the sum of nitrogen atoms from Ai, A 2 , A3, A 4 , A 5 , A 6 , and A 7 is 0, 1, 2, or 3;
- An, 22, A 33 , A 44 , A 55 , A 6 6, and A 77 are selected from the group consisting of electron pair, hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted vinyl ether, substituted or unsubstituted amide, substituted or unsubstituted amine, substituted or unsubstituted carboxylic acid, substituted or unsubstituted ester, substituted or unsubstituted alcohol, and substituted and unsubstituted silane or alkoxysilane; and
- An, A22, A 33 , A 44 , and A 55 is selected from the group consisting of substituted or unsubstituted vinyl ether, substituted or unsubstituted amide, substituted or unsubstituted amine, substituted or unsubstituted carboxylic acid, substituted or unsubstituted ester, substituted or unsubstituted alcohol, and substituted and unsubsituted silane or alkoxysilane.
- an moiety of an aromatic heterocycle from which the self-assembling monolayer is formed may comprise a substituted nitrogen, i.e., R 7 may be hydrocarbyl
- R 7 may be hydrocarbyl
- at least one nitrogen atom of the film-forming aromatic heterocycle be bonded to an acidic hydrogen atom, such that the compound may become deprotonated and the resultant negatively charged aromatic heterocyle is available to interact with copper (I) ions and copper (II) ions in a manner which forms a copper (I) rich organometallic adhesive film over the surface of the metal substrate.
- an aromatic N-bearing heterocycle which serves to form the monolayer comprise in which R 7 is hydrogen, and that the hydrogen be acidic, e.g., wherein it exhibits a pK a of between about 5 and about 13, such as between about 3.5 and about 11, such as between about 4 and about 10.
- the ring may be fused to aromatic or cycloalkyl groups, which may be homocyclic or heterocyclic .
- Suitable multi-functional compounds of structures 1(a) and (b) are those having structure (II), structure (III) and structure (IV):
- a 2 2, A 44 , A 55 , A 6 6, and A 77 are as defined in connection with structures (la) and (lb) .
- a 2 , A3, A 4 and A 5 are carbon atoms or nitrogen atoms and the sum of nitrogen atoms from A 2 , A 3 , A 4 and A 5 is 0, 1 or 2;
- A22, A33, A , and A 55 are selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted vinyl ether, substituted or unsubstituted amide, substituted or unsubstituted amine, substituted or unsubstituted carboxylic acid, substituted or unsubstituted ester, substituted or unsubstituted alcohol, and substituted and unsubsituted silane or alkoxysilane; and at least one of A22, A 33 , A 44 , and A 55 is selected from the group consisting of substituted or unsubstituted vinyl ether, substituted or unsubstituted amide, substituted or unsubstituted amine, substituted or unsubstituted carboxylic acid, substituted or unsubstituted ester, substituted or unsubstituted alcohol, and substituted and unsubsituted si
- the monolayer film may be formed from heterocyclics such as mercaptobenzamidazoles ,
- the corrosion inhibitor component of the adhesive promoting solution also contains a component which may be chemisorbed to the copper surface, such as benzotriazole or benzotriazole 5-carboxylic acid
- the process of the invention which combines treatment of the substrate with a conditioning solution and subsequent treatment with an adhesion promoting solution containing a heterocyclic corrosion inhibitor, is believed to form a complex of the self assembled monolayer from the conditioning solution, the corrosion inhibitor from the adhesion promoting solution and copper which interact, in some or all instances synergistically, to enhance binding of the copper substrate to the dielectric in the laminating step of the multi-layer circuit board manufacturing process.
- the alkaline cleaner may optionally comprise a molecule capable of forming a self-assembled monolayer (SAM) on a copper surface.
- SAM self-assembled monolayer
- organometallic conversion coating thereon.
- organometallic conversion coating to confirm the presence of a substantially uniform dark reddish brown to chocolate brown color, free of any marked patchiness or striations.
- the presence of the uniform brown color indicates the presence of a conversion coating that enhances the adhesion of the copper substrate to the dielectric in the subsequent laminating step of the manufacturing process..
- the surface of the copper conducting layer may have previously been provided with a tarnish-inhibiting coating, e.g., by incorporating the tarnish inhibitor into a resist stripping composition used in an
- Tarnish inhibitors used in such strippers are, for example, a triazole or other coating. Therefore, the conductive copper surface is generally micro-etched, cleaned, and immersed in a pre-dip composition prior to exposure to the adhesion promotion
- the surfaces of copper conducting layer are exposed to an etchant solution by immersion, spraying, cascading, or any other industry appropriate method.
- the etchant solution may be, for example, micro-etchant comprising about 12 to 20 wt . % Na persulfate and 2 to 5 wt . % sulfuric acid with a minor fraction of phenolsulfate, prepared for example by 40-60% dilution of a concentrated available under the trademark Enthone® PC-7077 (from Enthone Inc.) .
- the copper conducting layer is exposed to the etchant composition for durations between 10 to 120 seconds, such as between 20 to 60 seconds at solution temperatures generally between of 20°C and 40°C.
- Etching micro- roughens the copper surface and removes excess copper oxide and other oxide contaminants prior to the treatment according to the invention with a conditioning solution followed by an adhesion promoting solution.
- the etched copper conducting layer is next rinsed of the etchant composition, generally in warm water (tap water or deionized) for between 10 and 120 seconds.
- the rinse water is deionized water to allow better process control.
- the rinse water is preferably allowed to drain for 10 to 30 seconds in order to avoid undue dilution of the subsequent process composition.
- the etched surfaces of the copper conducting layer are next cleaned by immersion, spraying, cascading, or any other industry appropriate method cleaned of the layers in an alkaline cleaner.
- Useful compositions include Enthone® PC-7086 and Enthone® PC-7096 (10 to 15% concentrations, available from Enthone Inc.) .
- PC 7086 comprises monethanolamine (78 wt.%), 1- methylbenzotriazole (0.06 wt.%), KOH (10 wt.%), water (12 wt.%) and a quaternary ammonium salt (0.02 wt.%), and PC 7096
- the copper conducting layers are cleaned for a duration between 30 and 240 seconds, such as between 45 and 90 seconds at solution temperatures generally between of 30 °C and 50 °C.
- the cleaning composition optionally further comprises a molecule capable of forming a self assembled monolayer on a copper surface.
- Cleaning with an alkaline cleaner is effective to remove oily residues, residual photo-resist and other organic and inorganic contaminants present on the copper substrate as a result of prior steps in the process of manufacturing the circuit boards. It also neutralizes residual acid on the copper surface not fully removed in the rinse step following the micro-etch.
- the etched and cleaned copper conducting layer is next rinsed of the alkaline cleaning composition, generally in warm water (tap water or deionized) for between 10 and 120 seconds.
- the rinse water is deionized water to allow better process control.
- the rinse water is preferably allowed to drain for 10 to 30 seconds in order to avoid undue dilution of the subsequent process composition.
- the copper conducting layers are contacted with the pre-dip composition for durations between 30 and 240 seconds, such as between 45 and 90 seconds at solution temperatures generally between of 30°C and 50°C.
- the conditioning solution may usefully contain any, or any combination, of other components such as, e.g., iodide ion, e.g., in the form of KI, an ethanolamine such as MEA, an anionic surfactant, diethylene glycol butyl ether, and/or zinc ions, e.g., in the form of a zinc compound such as zinc iodide or zinc ammonium carbonate.
- iodide ion e.g., in the form of KI
- MEA ethanolamine
- anionic surfactant diethylene glycol butyl ether
- zinc ions e.g., in the form of a zinc compound such as zinc iodide or zinc ammonium carbonate.
- conditioner help to enhance bonding of the copper substrate to the dielectric in the laminating step that follows application of the adhesion promoting solution.
- the conditioner may contain certain other transition metal ions including, e.g., nickel, cobalt, silver, gold, palladium, or other platinum group metal.
- a further option is the presence of copper ions.
- Zinc or other transition metal is incorporated into the conditioner solution as a salt comprising a counteranion typically selected from the group consisting of chlorides, iodides, phosphates, carbonates, and various carboxylates , including, e.g., malates and oxalates. Oxides may also be used.
- the conditioner composition comprises zinc ion in the form of Zn 2+ , Zn 2+ /ammonia complex, zinc oxide, ZnC> 2 ⁇ or combinations thereof.
- the composition further includes one or more
- counteranions selected from the group consisting of chlorides, iodides, bromides, phosphates, carbonates, hydroxides, and various carboxylates, including, e.g., malates, oxalates; or in the case of zincate, the counterion is a cation such as Na + , K + and/or NH 4 + "
- the conditioner is alkaline, so that it can function as the alkaline cleaner for the copper substrate, thereby obviating the need for separate alkaline cleaning step.
- Alkalinity also promotes solubility of zinc sources such as, e.g., zinc oxide as well as oxides or hydroxides of other transition metals.
- the conditioner has a pH in the range between about 10 and about 15, still more preferably between about 10 and about 14, most preferably about 13.5 to about 14. A pH in these ranges also functions to maintain shelf life during storage and to extend conditioner bath life during process operations.
- Alkalinity can conveniently be imparted by the presence of an alkali metal hydroxide such as NaOH or KOH. Potassium hydroxide is preferred because of its favorable solubility and lesser susceptibility to carbonation by
- a particularly preferred source of zinc ions, especially in alkaline solution, is a zinc ammonium complex, or a combination of zinc ammonium complex and alkaline zincate salt.
- a highly useful commercial source of zinc is the
- ZINPLEX 15 which contains zinc ammonium complex (30-60 wt.%), ammonium carbonate (10-30 wt.%), ammonium hydroxide (0.1 to 10 wt . % basis NH 3 ) and minor to trace proportions of zinc oxide in the form of zincate ions.
- the zinc is predominantly present as Zn 2+ or a Zn 2+ /ammonia complex, but at the upper end of the range some zincate ion (ZnC>2 ⁇ ) may also be present and is believed to contribute to thermal stability of the conversion coating subsequently applied from the adhesion promoting solution.
- Zinc ion or other transition metal ion and in particular the combination of zinc ion and ammonia, are believed to promote the formation of a more effective protective film comprising the component that forms the self-assembled monolayer on the copper substrate.
- the complexing capability of ammonia further contributes to cleaning of the copper surface by contact with the cleaner/conditioner .
- contact with the alkaline conditioner is effective to remove oxidation and oily residues such as fingerprints from the copper surface and thereby enhance the effectiveness of the subsequently applied adhesion promoting composition.
- the conditioner is preferably substantially free of peroxide, more preferably substantially free of other oxidants as well.
- the conditioner comprise a solution having an oxidation potential not greater than about 0.8-1.02V, as typically exhibited, e.g., by purine, guanine and adenine.
- the conditioner is believed to promote the reduction of cupric ion to cuprous ion which in turn promotes the formation of complex of cuprous ion with the corrosion inhibitor component of the adhesion promoting solution, e.g., benzotriazole, thereby forming a conversion coating that enhances the bond strength between the copper substrate and the resin in the laminate.
- the concentration of iodide ion in the conditioning solution is between about 0.001 and about 1.00 wt . % .
- the conditioning solution also preferably contains an alcohol, more preferably a glycol ether such as, e.g., diethylene glycol butyl ether.
- an alcohol more preferably a glycol ether such as, e.g., diethylene glycol butyl ether.
- Other alcohols described herein for incorporation in the adhesion promoting solution can also optionally be present in the conditioning solution.
- the alcohol, and especially the preferred glycol ethers are examples of the preferred glycol ethers.
- the conditioning solution contains the alcohol component in a concentration between about 1.00 and about 20.00 wt . % .
- the conditioning composition may further contain an alkanolamine such as, e.g., methanolamine .
- Alkanolamines are cleaning agents with good chelating properties.
- an alkanolamine is present in a concentration between about 1.00 and about 20.00 wt . % .
- the conditioning solution include one or more surfactants, preferably anionic to wet the copper surface, reduce interfacial tension and enhance solubility of the component that forms the self-assembling monolayer on the substrate.
- anionic surfactants both aryl sulfonates and sulfate ester salts are preferred.
- anionic surfactants which can be included in the conditioning solution are Na 2-ethylhexyl sulfate, sold under the trade designation Niaproof 08 and Na
- dodecylbenzenesulfonate sold under the trade designation
- non-ionic surfactants are preferably present in the conditioning solution in a
- the conditioner comprises the
- Preferred embodiments of the conditioner generally also contain an anionic surfactant in a concentration between about 0.001 and about 0.03 wt . % and/or a glycol ether in a concentration between about 0.5 and about 5 wt . % .
- Preferred embodiments generally also contain an alkanolamine such as monoethanolamine in a concentration between about 0.5 and about 5 wt.%.
- the nitrogen- bearing aromatic heterocycle preferably comprises purine or a purine derivatives in a concentration between about 0.05 and about 2.5 wt . % .
- the etched copper conducting layer is next rinsed of the conditioner composition, generally in warm water (tap water or deionized) for between 10 and 120 seconds.
- the rinse water is deionized water to allow better process control.
- the rinse water is preferably allowed to drain for 10 to 30 seconds in order to avoid undue dilution of the subsequent process composition.
- the copper surface will be substantially dry or have only minimal wetness.
- the cleaned and etched surfaces of the copper conducting layer are next contacted with an adhesion promotion composition.
- Contact with the adhesion promotion composition may be by any conventional means, for example by immersion in a bath of the adhesion promotion composition or by spraying or any other means of contact. Contact may be as part of a continuous process. As is well understood in the art, immersion processes involve simply dipping the substrate into a bath of the
- Spray processes typically involve application using a series of automated squeegee-type mechanisms .
- the method of application is not critical to the invention.
- the tolerance for copper loading can be greater for spray processes than for dip processes because, for example, there is more bath stagnation with dip processes.
- the adhesion promotion composition may comprise an oxidizing agent.
- oxidizing agents include hydrogen peroxide and persulfates, e.g., ammonium persulfate, potassium persulfate, sodium persulfate, and the like.
- hydrogen peroxide is incorporated into the adhesion promotion composition of the invention as an oxidizing agent to oxidize copper on the substrate.
- the oxidizing agent e.g., hydrogen peroxide
- the concentration of oxidizing agent e.g., hydrogen peroxide, is typically no greater than about 20%, and in certain preferred embodiments it is no greater than about 10%.
- One preferred concentration of hydrogen peroxide is from about 0.5% by weight of the adhesion promotion composition to about 4% by weight. It has been found that when the concentration of hydrogen peroxide in the adhesion promotion composition is too high the structure of the roughened surface of the conducting layer forms a somewhat dendritic structure which is more fragile than the desired roughening effect, so that it forms a weaker bond than when lower
- the H 2 C> 2 solution added to the composition is 35% concentrated H 2 O 2 , rather than a 100% concentrated H 2 O 2 .
- the 20%, 10%, 4% etc. numbers provided above are % of 100% H 2 O 2 in the final composition, not % of 35% H 2 O 2 in the final composition.
- the composition is preferably initially substantially free of copper and any other transition metals which have a tendency to destabilize the oxidizing agent.
- copper ions are avoided in the initial solution because they have a tendency to destabilize hydrogen peroxide. This requirement pertains to the initial composition in that the copper is avoided in the fresh composition before its use to promote adhesion. Upon use, however, copper is not excluded from the composition because, in fact, copper does tend to accumulate in the solution during use.
- transition metal ions have been found to contribute to the thermal stability of the conversion coating without destabilizing the peroxide.
- the transition metals beneficially contained in the initial bath include nickel, cobalt, silver, gold, palladium and other platinum group metals.
- the adhesion promoting composition is "substantially" free of transition metals in that any trace amounts in the composition are sufficiently low as to not significantly contribute to degradation of the oxidizing agent; for example, sufficiently low as to not increase the degradation rate by more than about 10%.
- the adhesion promotion composition comprises one or more inorganic acids for the main purpose of solubilizing copper, and maintaining other components of the composition in solution.
- a variety of acids such as mineral acids including phosphoric acid, nitric acid, sulfuric acid, and mixtures thereof are workable.
- both HNO 3 and H 2 SO 4 are employed. It has been discovered that in addition to solubilizing the Cu, H 2 S0 4 helps to moderate the etch rate, and therefore help prevent over-etching of the substrate in isolated areas.
- the HNO 3 increases the etch rate; increases the
- the overall acid concentration in the composition is generally at least 1%, preferably at least 8%, and in certain preferred embodiments at least 14% of the composition.
- the etch rate is slowed excessively if the acid concentration is too high, with the exception of nitric acid, and can yield an organometallic conversion coating which is nonuniform and too light in color. For this reason, the acidity level in previous compositions had been typically selected to be about 20%.
- the coating is not lightened as would otherwise be expected with an acid level elevated to about 25%.
- the overall acid level is typically maintained below about 50%. In one preferred embodiment, therefore, there is between about 22% and about 28% acid, including about 20% H 2 S0 4 (50% grade) and about 5% HN0 3 (95% grade) .
- the inorganic acid constitutes at least about 30% of the composition.
- Another preferred embodiment employs 28% H 2 SO 4 (50% grade) and 5% HNO 3 (95% grade) .
- HNO 3 is employed in these preferred embodiments because it has been discovered that it has a unique ability to solubilize the inhibitor-Cu complex better than do other mineral acids. It contributes to the etch rate, improves the topography of the conversion coating and enhances copper loading capacity of the adhesive promoting bath. While weight fractions given above are percentages of the acids in the final composition and are based on use of 100% concentrated acid, as discussed above, the preferred forms of the acids actually added are 50%
- the total mineral acid content is preferably at least about 20 wt.%. It is further preferred that nitric acid be present in a concentration of at least the difference between the total mineral acid content and 20 wt% .
- the overall composition is formulated to be compatible therewith.
- thiourea-based complexing agents are specifically avoided due to the explosive nature thereof when mixed with HNO 3 .
- triazoles, tetrazoles, imidazoles and mixtures thereof have been proposed as corrosion inhibitors in adhesion promotion compositions.
- Useful corrosion inhibitors include benzotriazole, triazole, benzimidazole, imidazole, Benzotriazole (BTA) compounds are most preferred due to their effectiveness in chelating Cu, their effectiveness to inhibit corrosion, and their effectiveness to help darken the
- the most preferred BTA compound currently is 1 , 2 , 3-benzotriazole , also known as aziamino-benzene or benzene azimide, and has the formula
- Purine and the purine derivatives of Formula I can also be used, as may the multi-functional compounds of Formulas 1(a), 1(b), III, IV and V. Particularly desirable results are achieved with corrosion inhibitor concentrations of at least 0.1%, more preferably more than 0.5% by weight, and something more than 1% by weight. Generally, the corrosion inhibitor will be present in the composition in an amount no greater than 20%, preferably no greater than 10%, and more preferably less than 5% by weight of the total weight of the adhesion promotion
- compositions High concentrations, such as more than 5% can be desirable as they can allow a reduction in the processing time. In certain preferred embodiments, however, the concentration is less than 5% or even less than 1%.
- the invention also employs various additives to the adhesion promoting composition, as discussed in more detail below, selected from among monomeric and oligomeric alcohols, and polymeric, oligomeric, and monomeric alcohol derivatives, including, but not limited to alcohol sulfates, sulfonates, and ethoxylates .
- Preferred embodiments of the invention may employ a sulfonated anionic surfactant. It has been discovered that in addition to surface wetting, this surfactant helps to stabilize the H 2 O 2 .
- This surfactant is dodecylbenzene sulfonic acid (DDBSA) .
- DDBSA is available from Ashland Distribution Company of Santa Ana, California; or from Pilot Chemical Company of Santa Fe Springs, California under the trade designation Calsoft LAS 99.
- surfactants include sodium dodecylbenzene sulfonate available from Witco Corporation, Organic Division, of New York, New York under the trade designation Witconate 1850; the isopropyl amine salt of branched alkyl benzene sulfonate available from Stepan Company of Northfield, Illinois under the trade designation Polystep A- 11; and TEA dodecylbenzene sulfonate available from Norman, Fox & Company of Vernon, California under the trade designation Norfox T-60.
- the sulfonated anionic surfactant is used in a quantity sufficient to achieve surface wetting and H 2 O 2
- the stabilization which quantity can vary depending on the overall composition of the adhesion promoter.
- One currently preferred embodiment includes at least about 0.0001% of sulfonated anionic surfactant.
- the sulfonated anionic surfactant concentration is at least about 0.005%, preferably at least about 0.1%; and is less than about 10%, preferably less than about 5%, more preferably less than about 2%.
- One specific example employs 0.002% of this surfactant, particularly DDBSA.
- a currently preferred embodiment of the invention also incorporates a sulfated anionic surfactant.
- a sulfated anionic surfactant is sodium 2-ethylhexyl sulfate, also known as 2-ethylhexanol sulfate sodium salt, having the formula C 4 H 9 CH (C 2 H 5 ) CH 2 S0 4 Na .
- Niaproof 08 which contains 38.5 to 40.5% sodium 2-ethylhexyl sulfate and the balance water.
- Alternatives include sodium tetradecyl sulfate available from Niacet under the trade designation
- Niaproof 4 sodium lauryl sulfate available from Stepan Company of Northfield, Illinois under the trade designation Polystep B- 5, and sodium n-decyl sulfate available from Henkel
- sulfated anionic surfactant compound surprisingly permits the acidity level to be raised, without the expected detrimental effect of lightening the coating. Because the acidity level can be raised in this manner, copper loading is increased. It also helps darken the coating.
- This compound is present in this embodiment in a concentration sufficient to increase copper loading without substantial lightening of the coating.
- the typical concentration is at least about 0.001%, and preferably at least about 0.1%.
- the concentration of sulfated anionic surfactant is no greater than about 10%, and preferably no greater than about 5%. One preferred range is between about 0.05 and 2%.
- the sulfated anionic surfactant concentration is about 0.5%. In another it is 0.15%.
- the composition also includes a nonionic surfactant.
- Anionic and nonionic surfactants complement each other in the action of the adhesion promoter to produce a conversion coating with the most favorable properties for enhancing the adherence of resin to copper conductor.
- Anionic surfactants are effective in removing oily/greasy residue on the copper substrate and preventing their re-deposition.
- anionic surfactants also comprise a
- nonionics assures that the oily residues are removed even in hard water adhesion promoting formulations because, lacking a negative charge, nonionics are unaffected by calcium or
- this surfactant is one or more ethoxylated nonylphenols , such as polyoxyethylene nonylphenol.
- Polyoxyethylene nonylphenol is available from Dow Chemical Company of Midland, Michigan under the trade designation Tergitol NP9.
- Alternatives include an ethoxylated nonylphenol available from Dow Chemical Company of Midland, Michigan under the trade designation Tergitol NP8, nonylphenoxypolyethoxyethanol available from Union Carbide
- concentration of this surfactant is selected to be sufficient to improve peel strength.
- One currently preferred embodiment includes at least about 0.0001% of an ethoxylated phenol derivative. As a general proposition, the concentration is at least about 0.01%, preferably at least about 0.2%; and is less than about 10%, preferably less than about 5%. One preferred range is between about 0.0001% and about 2%. One exemplary embodiment contains 0.02%.
- the alcohols may be monohydric or they may be multihydric, e.g., dihydric (i.e., diols), trihydric (i.e., triols), tetrahydric, pentahydric, etc.
- the alcohols may be primary, secondary, and/or tertiary
- Suitable aliphatic alcohols include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n- butanol, isobutanol, tert-butanol , pentanol, neopentanol, hexanol, cyclohexanol , furfuryl alcohol, and tetrahydrofurfuryl alcohol, and so forth.
- monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n- butanol, isobutanol, tert-butanol , pentanol, neopentanol, hexanol, cyclohexanol , furfuryl alcohol, and tetrahydrofurfuryl alcohol, and so forth.
- alcohols having higher boiling points e.g., above about 110°C are preferred over alcohols having
- Suitable aliphatic saturated alcohols include dihydric alcohols, e.g., diols, such as ethylene glycol;
- propylene glycols such as propane-1 , 2-diol and propane-1 , 3-diol ; butylene glycols such as butane-1, 2-diol, butane-1 , 3-diol , butane-2 , 3-diol , butane-1 , 4-diol , and 2-methylpropane-l, 3-diol; pentylene glycols such as pentane-1 , 5-diol , pentane-1, 4-diol, pentane-1 , 3-diol , 2 , 2-dimethyle-l , 3-propanediol , etc.; hexylene glycols such as hexane-1, 2-diol, hexane-1 , 4-diol, hexane-1, 5- diol, hexane-1 , 6-diol , 2-methylpentane-2, 4-diol,
- Suitable aliphatic saturated alcohols also include triols, such as glycerol, butanetriol, pentanetriol , etc.
- Oligomeric alcohols are those alcohols and alcohol derivatives, e.g., ethers, that comprise multiple repeat units of the general formula:
- R lr R 2 , R3, R4, R5, and R6 may be hydrogen or a low molecular weight hydrocarbon having, generally from 1 to about 6 carbon atoms, more generally from 1 to about 3 carbon atoms, and even more generally from 1 to 2 carbon atoms.
- the number of repeat units in an oligomer is low, such as between about 2 and about 12, more generally between about 2 and about 6, more generally, 2, 3, or 4.
- Suitable oligomeric alcohols include diethylene glycol, diethylene glycol methyl ether, diethylene glycol dimethyl ether, triethylene glycol,
- unsaturated diols such as butene diol, hexene diol, and acetylenics such as butyne diol .
- An example of a suitable trihydric alcohol is glycerol.
- This additive is present in this embodiment at a concentration sufficient to increase copper loading of the composition. Typically, this concentration is at least about 0.01%, and in certain embodiments is at least about 0.5%. The concentration of this additive is no greater than about 20%, and in certain embodiments no greater than about 10%.
- Preferred alcohols include propylene glycol and/or oligomeric polypropyleneglycol having a molecular weight generally between about 300-4000 g/mol and about 4000 g/mol, preferably about 80 g/mol and about 76.09 g/mol.
- the propylene glycol and/or oligomeric polypropyleneglycol may be added in a concentration range between about 0.1 wt . % and about 5 wt.%, more suitably between about 0.2 wt.% and about 1 wt.%, such as about 0.5 wt.%.
- compositions containing this oligomer have copper-loading capacity of about 30 grams copper per liter solution up to about 35 and even about 40 g/L in dip process applications. In spray process and flooded immersion process applications, automated and conveyorized applications, these compositions have copper-loading capacity of up to about 45 g/L and even up to 50 g/L.
- This triethylene glycol is an oligomer in that it is a molecule of intermediate relative molecular mass with a structure comprising a small number of units derived from molecules of lower relative molecular mass. This is in contrast to a polymer, which has a high relative molecular mass.
- This triethylene glycol is also oligomeric in that its properties vary significantly with removal of one of its units; as opposed to polymeric compounds, with which removal of one or a few units has a relatively negligible effect on molecular properties.
- This triethylene glycol has the molecular formula C 6 H 14 O 4 , more specifically, HO(C 2 H 4 0)3H, and a molecular weight of 150.17.
- concentration of TEG is no greater than about 20%
- the TEG concentration is about 1%.
- the TEG also has the added benefit of helping to stabilize the H 2 O 2 .
- composition optionally also includes an
- stabilizing agents include, for example, dipicolinic acid, diglycolic and thiodiglycolic acid, ethylene diamine tetra-acetic acid and its derivatives, magnesium salt of an aminopolycarboxylic acid, sodium silicate, phosphates, phosphonates , and sulfonates.
- the stabilizing agent is present in an amount of from 0.001% or even at least 0.005% by weight of the adhesion promotion composition. Generally there is no more than 1% by weight in the composition.
- the currently preferred composition contains an additional stabilizing agent, but relies primarily on the stabilizing function of the TEG, as described above.
- the composition further includes a source of halide ions.
- This source is preferably HC1, and provides a chloride ion concentration in the range of about 10 pp to 100 ppm, preferably between about 20 ppm and about 100 ppm, even more preferably between about 30 ppm and about 100 ppm.
- the units "ppm" in the context of an aqueous composition are in terms of mass: volume, so 1 ppm is generally equivalent to 1 microgram per milliliter, or about 1 mg per liter.
- the chloride ion concentration range is between about 60 and 65 ppm. In one embodiment, the chloride ion concentration range is between about 65 and 75 ppm. In one embodiment, the chloride ion concentration range is between about 75 and 85 ppm. In one embodiment, the chloride ion concentration range is between about 85 and 95 ppm. Preferred ranges are different for other embodiments depending on the overall composition and
- concentration of between about 20 ppm and about 100 ppm is preferred in one embodiment in order to achieve Cl ⁇ ion content in service of on the order of about 20 to 80 ppm.
- the adhesion promotion composition is manufactured by mixing the components in an aqueous solution, preferably using deionized water.
- hydrogen peroxide is added to the composition in a diluted form.
- the adhesion promotion composition is ready to use and can be used directly for immersion or other exposure of the substrate.
- the invention is a concentrate that is to be diluted to form the composition for immersion or other exposure.
- An exemplary ready-to-use composition includes the following :
- DBSA dodecylbenzene sulfonic acid
- the concentrate has the following
- DBSA dodecylbenzene sulfonic acid
- the H 2 O 2 is added later and is not included in the concentrate formulation. This concentrate is then incorporated into an overall solution in which, for example, about 43 wt% is this concentrate, about 7 wt% is H 2 O 2 , and about 50 wt% is water.
- adhesion promoting composition also contain a transition metal ion but it has been found important to be selective in choosing a transition metal ion for the composition.
- transition metal ions can adversely affect the stability of the peroxide component of the composition and/or promote release of excessive volumes of hazardous gases, e.g., H 2 , O 2 , ⁇ and SO x .
- other transition metal ions can contribute to the thermal stability of the conversion coating produced in the adhesion promoting step of the process without material adverse effect on the stability of the peroxide and without generating excessive volumes of hazardous gases.
- Preferred transition metal ions for inclusion in the adhesion promoting solution include zinc, nickel, copper, cobalt, silver, gold, palladium and other platinum group metals.
- the transition metal ions are preferably incorporated into the adhesion promoting composition in the form of their salts.
- the preferred adhesion promoting solution contains zinc, nickel, copper, cobalt, silver, gold, palladium or other platinum group metals in the form of their cations plus a counteranion derived from the salt that serves as the transition metal ion.
- the transition metal ion comprises Zn, Ni, Co, Ag, Au, Pd or other platinum group metals, still more preferably Zn, Ni, Co, or Ag, or Zn, Ni, or Co.
- the transition metal is introduced in the form of a sulfate, chloride, bromide, iodide, phosphate, or any of various carboxylates , including, e.g., malates and oxalates.
- Complex salts such as, e.g., zinc ammonium halides, can also be used.
- the adhesion promoting solution contains the
- transition metal ion in a concentration between about 0.02 wt . % and about 2 wt.%, a nitrogenous corrosion inhibitor in a
- the composition contains one or more anionic surfactants in a concentration between about 0.01 and 1 wt.%, and an alcohol in a concentration between about 0.1 and 3 wt.%. Still more preferably, the composition further comprises a one or more nonionic surfactants in a concentration between about about 0.0005 and about 0.2 wt.%. In each of these various embodiments, it is preferred that the composition further comprise nitric acid in a concentration between about 0.5 and about 15 wt.%.
- the transition metal ion component of the adhesion promoting solution comprises zinc ion.
- a particularly preferred source of zinc ion is ZnS0 4 .
- the adhesion promoting composition comprises:
- balance deionized water typically 45 to 70 wt . % .
- Contact of the copper surface with the adhesion promotion composition is typically at a temperature between about 20°C and about 40°C, though temperatures reasonably outside this range are operable.
- the contact time is generally no less than 1 second, preferably no less than 5 seconds, and often at least 10 seconds, most preferably at least 30 seconds.
- the maximum contact time may be up to 10 minutes, although preferably the contact time is no greater than 5 minutes, most preferably no greater than 2 minutes.
- a contact time of about 1 minute or less than 1 minute is standard.
- the copper conducting layer having the organometallic conversion coating thereon is next rinsed of the adhesion promotion composition, generally in warm water (tap water or deionized) for between 10 and 120 seconds.
- the rinse water is deionized water to allow better process control.
- the rinse water is preferably allowed to drain for 10 to 30 seconds and the surface is then dried.
- a Pre-preg layer may be placed directly adjacent to the copper surface and the Pre-preg layer adhered directly to the copper surface in the adhesion step, forming a multi-layer PCB.
- Appropriate substrate materials for a printed circuit board include, for example, high-pressure laminates (i.e., layers of fibrous materials bonded together under heat and pressure with a thermosetting resin) .
- a laminate layer comprises an electrical-grade paper bonded with phenolic or epoxy resin or a continuous-filament glass cloth bonded with an epoxy-resin system.
- Specific examples of laminate layers are: XXXPC which is an electrical paper
- the organic circuit board material is an FR-4 laminate layer that is placed on top of, and in intimate contact with the passive component pattern, and the two are laminated together . [ 0098 ] Generally in the adhesion step heat and pressure are applied to initiate the adhesion reaction.
- adhesion step mechanical bonding is due to penetration of the polymeric material of the insulating layer into the micro-roughened surface provided in the adhesion promotion step.
- a pre-preg insulating layer is applied directly to the micro-roughened surface, i.e., preferably without any intermediate metal deposition onto the micro-roughened surface or the like, although optionally with a post-treatment cupric oxide removal or reduction operation to further enhance the bond strength as disclosed in U.S. Pat. No. 6,294,220.
- Pressure is applied by placing the layers that are to form the multi-layer laminate of the PCB in a press. Where pressure is applied it is generally from 100 to 400 psi, preferably from 150 to 300 psi.
- the temperature of this adhesion step will generally be at least about 100°C, preferably between about 120°C and about 200°C.
- the adhesion step is generally carried out for any period from 5 minutes to 3 hours, most usually from 20 minutes to 1 hour, but is for sufficient time and pressure and at a sufficiently high temperature to ensure good adhesion between the first and second layers.
- the polymeric material of the insulating layers generally an epoxy resin tends to flow ensuring that the conductive pattern in the metal is
- the exemplary arrangement discussed at length herein is a pre-preg layer adhered to a copper surface
- the invention also includes improving adhesion of other dielectric materials, whether permanent or temporary, to copper.
- the invention improves adhesion between copper and a solder mask that is dielectric. It similarly improves copper adhesion with inks, polymeric photo-resists, and dry films. It also has application in connection with photo-imageable
- AOS AOS
- PC-7077 is a conventional micro-etchant that contains Na persulfate, Na phenolsulfate and sulfuric acid.
- AlphaPREP® PC-7030 (100% concentration, available from Enthone Inc.) by immersion or spraying the coupons in or with the adhesion promotion composition.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 45 seconds .
- One set of coupons was contacted with AlphaPREP® PC-7030 for 1 minute.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes.
- the solution temperature between of 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and concentrations :
- the copper coupons treated in this manner were inspected for coating appearance and defects prior to lamination to a standard FR4 pre-preg laminate such as Isola FR370HR (high Performance FR-4 material) .
- AO AO control processes and were carried out in order to provide comparative data for peel strength, conversion coating appearance, and number of solder dip cycles to delamination .
- the AO control processes were carried out in a similar manner to the AOS control processes of Example 1, except that the chloride ion concentration of the adhesion promotion composition was increased to between about 85 and about 95 ppm.
- microetchant Enthone® PC-7077 40-60% concentration, available from Enthone Inc.
- AlphaPREP® PC-7030 (100% concentration, available from Enthone Inc.) by immersion or spraying the coupons in or with the adhesion promotion composition.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 45 seconds .
- One set of coupons was contacted with AlphaPREP® PC-7030 for 1 minute.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes.
- the solution temperature between of 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and concentrations :
- MSA Methane Sulfonic Acid
- Monopropylene glycol is preferably included to inhibit premature sludge formation in the adhesion promoting composition bath.
- the copper coupons treated in this manner were inspected for coating appearance and defects prior to lamination to a standard phenolic filled, halogen-free and/or polyimide pre-preg laminate.
- Useful phenolic filled dielectrics include those sold under the trade designations Isola 370H, FR408HR, and Isola IS 410.
- Useful halogen free, high glass transition temperature dielectrics include DE 156 and DE 155, while useful polyimides include Isola P95 and P96.
- microetchant, cleaner, and adhesion promotion compositions These processes, designated Al, were control processes and were carried out in order to provide comparative data for peel strength, conversion coating appearance, and number of solder dip cycles to delamination .
- the Al control processes were carried out in a similar manner to the AO control processes of Example 2, except that the copper coupons were contacted with a pre-dip composition prior to contact with the adhesion promotion composition .
- microetchant Enthone® PC-7077 40-60% concentration, available from Enthone Inc.
- SAM8R-1 has the following composition:
- bicarbonate ( a 2 C03 « H 2 0, 30 grams/Liter) for 60 seconds at a solution temperature between of 43°C ⁇ 6°C.
- the water was allowed to drain from the coupons for 10 to 20 seconds to avoid unnecessary dilution of the adhesion promotion composition.
- the adhesion promotion composition contained the following components and concentrations :
- the copper coupons were pre- dipped in a composition comprising a molecular capable of forming a self-assembled monolayer on a copper surface.
- adhesion promotion composition was further modified with polypropylene glycol.
- adhesion promotion processes were carried out on three sets of 1" (25.4 mm) by 2" (50.8 mm) copper coupons according to the following protocol:
- AlphaPREP® PC-7030M (100% concentration, available from Enthone Inc.) modified by adding polypropylene glycol or propylene glycol (0.5 to 1.0 wt . %) by immersing or spraying the coupons in or with the adhesion promotion composition.
- One set of coupons was contacted with
- AlphaPREP® PC-7030 for 45 seconds. One set of coupons was contacted with AlphaPREP® PC-7030 for 1 minute. One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes. The solution temperature between of 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and concentrations :
- the copper coupons were pre- dipped in a composition comprising a molecular capable of forming a self-assembled monolayer on a copper surface.
- adhesion promotion composition was further modified with methane-sulfonic acid.
- AlphaPREP® PC-7030 (100% concentration, available from Enthone Inc.) modified by adding methanesulfonic acid (2 wt . %) , so that the solution contained nitric, sulfuric and methanesulfonic acids, and immersing or sprayingthe coupons in or with the adhesion promotion composition.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 45 seconds .
- One set of coupons was contacted with AlphaPREP® PC-7030 for 1 minute.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes.
- the solution temperature was 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and
- the copper coupons were pre- dipped in a composition comprising a molecule capable of forming a self-assembled monolayer on a copper surface. Additionally, the adhesion promotion composition was further modified with methanesulfonic acid and polypropylene glycol.
- microetchant Enthone® PC-7077 40-60% concentration, available from Enthone Inc.
- AlphaPREP® PC-7030 (100% concentration, available from Enthone Inc.) modified by adding polypropylene glycol (0.5 to 1.0 wt . %) having an average molecular weight 76.1 g/mol, available from KingChem or Aldrich Chemical, and by adding methanesulfonic acid (2 wt . %) , available from Huntsman Corporation thereby producing a solution
- the coupons were then immersed in and/or sprayed with the adhesion promotion composition.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 45 seconds.
- One set of coupons was contacted with AlphaPREP® PC-7030M for 1 minute.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes.
- the solution temperature between of 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and concentrations: Component Concentration
- the copper coupons were cleaned in an alkaline cleaner composition further comprising a
- composition was further modified with methanesulfonic acid and polypropylene glycol .
- the adhesion promotion processes were carried out on three sets of 1" (25.4 mm) by 2" (50.8 mm) copper coupons according to the following protocol: 1. Contact the surfaces of three copper coupons with microetchant Enthone® PC-7077 (40-60% concentration, available from Enthone Inc.) by spraying the coupons in the microetchant composition for 30 to 45 seconds, or immersing them with the solution, in either case at a solution temperature between of 27°C ⁇ 3°C.
- AlphaPREP® PC-7030 (100% concentration, available from Enthone Inc.) modified by adding polypropylene glycol (0.5 wt . %) having a molecular weight of 76.1 g/mol, and by adding methanesulfonic acid (2 wt . %) so that the
- composition contained sulfuric, nitric and methanesulfonic acid. Contact was by immersion or spraying or both. One set of coupons was contacted with AlphaPREP® PC-7030M for 45 seconds. One set of coupons was contacted with
- AlphaPREP® PC-7030 for 1 minute.
- One set of coupons was contacted with AlphaPREP® PC-7030 for 2 minutes.
- the solution temperature was 43°C ⁇ 6°C.
- the adhesion promotion composition contained the following components and concentrations :
- Adhesion promotion processes were carried out on test copper coupons that were designated BOS, B0, Bl, B3, B6, B7, and B8.
- Adhesion promotion processes BOS, B0, Bl, B3, B6, B7, and B8 were identical to process AOS, AO, Al, A3, A6, A7, and A8 , respectively, except that in each of BOS, B0, Bl, B3, B6, B7, and B8, the adhesion promotion compositions were formulated with 30 g/L copper ions, in order to simulate a working adhesion promotion process in which the adhesion promotion composition has accumulated a substantial copper ion concentration .
- Example 15 Lamination Process
- One surface of the copper coupon and one surface of the pre-preg were each coated by a DuPontTM Tedlar® PVF Film.
- Tedlar® coated sides were then contacted with platens and compressed together in a hydraulic press at about 765 kPa (about 111 PSI) for 5 minutes.
- the pressure was increased to 1917 kPa (about 211 PSI) for 60 minutes.
- solder pot dip test is conducted by lowering a portion of the copper laminated pre-preg into molten solder at a temperature of 260°C for 10 second interval cycles. The number of cycles until delamination is recorded.
- Peel strength is determined with the Instron 4442 Instrument (ASTM standard) . The peel strength is run on five samples .
- the etch rate of copper in the adhesion promotion composition was determined by measuring the copper ion concentration in the adhesion promotion composition.
- “Appearance” is a qualitative, eyeball measurement of the appearance of the organometallic conversion coating.
- a rating of 5 means that the coating was an excellent dark brown color that the industry associates with a strongly adhesive coating.
- a 4 rating means that the coating was good, uniform, and dark reddish brown.
- a 3 rating means that the coating was fairly uniform and still dark brown, but less so than a 4 or 5. Ratings of 1 or 2 mean that the coating was uneven; the dark reddish brown color was spotty.
- an adhesion promotion composition can be used for an extended duration when copper coupons are pre-dipped in a composition comprising a molecule capable of forming a self-assembled monolayer .
- microetchant Enthone® PC-7077 40-60% concentration, available from Enthone Inc.
- Example 17 A control (Experiment #7) was run using the adhesion promoting solution of Example 16 after conditioning only with a standard alkaline cleaning solution.
- the coupons were laminated to a dielectric material generally in the manner described above. In some instances, the lamination took place after lOx IR-reflow, and in other cases lamination was conducted before reflow.
- formulations is contacted with copper substrates through
- the adhesion promoting solution was spiked with either 1, 5, or 10 g/1 copper.
- the treated coupons were then laminated to a dielectric material at either 15.5 or 24.1 bars and peel strength tests conducted on the resulting laminated composites.
- Example 16 was used without adulteration.
- Example 18 Additional tests were run generally in the manner described in Example 18. Conditioner #2 was used, followed by the adhesion promoting solution of Example 16. Both the conditioner and the adhesion promoting solution were doped with copper ions in a concentration of 40 g/1. The dwell time between application of the conditioner and application of the adhesion promoting solution was varied.
- Example 21 generally in the manner described in Example 21 except that the copper ion concentration in the adhesion promoting formulations was 10 g/1 and only dielectric substrates 370 HR, 408 HR and IS 410 were tested.
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- Materials Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Manufacturing Of Printed Wiring (AREA)
- Paints Or Removers (AREA)
- Laminated Bodies (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020167006853A KR20160056892A (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
JP2016534564A JP2016535453A (en) | 2013-08-16 | 2013-08-16 | Promoting adhesion of printed circuit boards |
CN201380078898.8A CN105453711A (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
PCT/US2013/055368 WO2015023295A1 (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
EP13753393.1A EP3033929A1 (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2013/055368 WO2015023295A1 (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015023295A1 true WO2015023295A1 (en) | 2015-02-19 |
Family
ID=49036657
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/055368 WO2015023295A1 (en) | 2013-08-16 | 2013-08-16 | Adhesion promotion in printed circuit boards |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP3033929A1 (en) |
JP (1) | JP2016535453A (en) |
KR (1) | KR20160056892A (en) |
CN (1) | CN105453711A (en) |
WO (1) | WO2015023295A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP4057783A1 (en) * | 2021-03-10 | 2022-09-14 | INTEL Corporation | Dielectric-to-metal adhesion promotion material |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN108535959B (en) * | 2018-02-28 | 2021-09-24 | 苏州城邦达益材料科技有限公司 | Photosensitive adhesive and preparation method and application thereof |
CN110029348A (en) * | 2018-08-09 | 2019-07-19 | 苏州纳勒电子科技有限公司 | It is a kind of for handling the micro-corrosion liquid on copper surface |
CN110205630A (en) * | 2018-08-09 | 2019-09-06 | 苏州纳勒电子科技有限公司 | A kind of micro-corrosion liquid that can be used for impurity removing |
CN110129802A (en) * | 2019-06-18 | 2019-08-16 | 博敏电子股份有限公司 | A kind of printed board novel antioxidant and its application |
CN113903502A (en) | 2019-11-14 | 2022-01-07 | 宸盛光电有限公司 | Conductive structure with self-assembly protective layer and self-assembly coating composition |
TW202402773A (en) * | 2022-03-24 | 2024-01-16 | 日商三菱瓦斯化學股份有限公司 | Composition for protecting copper surface, and method for producing semiconductor intermediate and semiconductor using same |
CN116607136B (en) * | 2023-06-01 | 2024-01-05 | 武汉创新特科技有限公司 | Bonding agent for circuit board surface treatment and preparation method thereof |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010015345A1 (en) * | 1999-11-29 | 2001-08-23 | Applied Materials, Inc. | Planarized copper cleaning for reduced defects |
US20050067378A1 (en) * | 2003-09-30 | 2005-03-31 | Harry Fuerhaupter | Method for micro-roughening treatment of copper and mixed-metal circuitry |
US20050126429A1 (en) * | 2003-12-12 | 2005-06-16 | Bernards Roger F. | Additives to stop copper attack by alkaline etching agents such as ammonia and monoethanol amine (MEA) |
US20120168075A1 (en) * | 2008-03-21 | 2012-07-05 | Enthone Inc. | Adhesion promotion of metal to laminate with multi-functional molecular system |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4605446B2 (en) * | 2004-09-08 | 2011-01-05 | 日立化成工業株式会社 | Multilayer wiring substrate, semiconductor chip mounting substrate, semiconductor package, and manufacturing method thereof |
JP4804847B2 (en) * | 2005-09-15 | 2011-11-02 | 新日鐵化学株式会社 | Method for producing copper clad laminate |
US8088246B2 (en) * | 2009-01-08 | 2012-01-03 | Cordani Jr John L | Process for improving the adhesion of polymeric materials to metal surfaces |
US10577507B2 (en) * | 2013-03-16 | 2020-03-03 | Prc-Desoto International, Inc. | Alkaline cleaning compositions for metal substrates |
-
2013
- 2013-08-16 JP JP2016534564A patent/JP2016535453A/en active Pending
- 2013-08-16 CN CN201380078898.8A patent/CN105453711A/en active Pending
- 2013-08-16 KR KR1020167006853A patent/KR20160056892A/en not_active Application Discontinuation
- 2013-08-16 EP EP13753393.1A patent/EP3033929A1/en not_active Withdrawn
- 2013-08-16 WO PCT/US2013/055368 patent/WO2015023295A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20010015345A1 (en) * | 1999-11-29 | 2001-08-23 | Applied Materials, Inc. | Planarized copper cleaning for reduced defects |
US20050067378A1 (en) * | 2003-09-30 | 2005-03-31 | Harry Fuerhaupter | Method for micro-roughening treatment of copper and mixed-metal circuitry |
US20050126429A1 (en) * | 2003-12-12 | 2005-06-16 | Bernards Roger F. | Additives to stop copper attack by alkaline etching agents such as ammonia and monoethanol amine (MEA) |
US20120168075A1 (en) * | 2008-03-21 | 2012-07-05 | Enthone Inc. | Adhesion promotion of metal to laminate with multi-functional molecular system |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP4057783A1 (en) * | 2021-03-10 | 2022-09-14 | INTEL Corporation | Dielectric-to-metal adhesion promotion material |
Also Published As
Publication number | Publication date |
---|---|
CN105453711A (en) | 2016-03-30 |
JP2016535453A (en) | 2016-11-10 |
EP3033929A1 (en) | 2016-06-22 |
KR20160056892A (en) | 2016-05-20 |
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