CA1224276A - Process for producing printed circuits - Google Patents
Process for producing printed circuitsInfo
- Publication number
- CA1224276A CA1224276A CA000476796A CA476796A CA1224276A CA 1224276 A CA1224276 A CA 1224276A CA 000476796 A CA000476796 A CA 000476796A CA 476796 A CA476796 A CA 476796A CA 1224276 A CA1224276 A CA 1224276A
- Authority
- CA
- Canada
- Prior art keywords
- carried out
- process according
- reducing
- heating
- base material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/18—Pretreatment of the material to be coated
- C23C18/20—Pretreatment of the material to be coated of organic surfaces, e.g. resins
- C23C18/28—Sensitising or activating
-
- 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
- H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
- H05K3/18—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material
- H05K3/181—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using precipitation techniques to apply the conductive material by electroless plating
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention provides a method of manufac-ture of contact switches having conductive coatings of increased adhesive strength and resolution for producing through-contacts in boreholes of printed circuit boards, com-prising the steps of providing a base material, drilling bore-holes in said material, cleaning, activating and reducing said base and producing a coating thereon, and heating-up said base material at temperatures within the range from 100°C to 150°C
immediately after said reducing step, said heating-up step being carried out for from 5 minutes to 2 hours, said reducing step being carried out by means of a reducing agent selected from the group consisting of alkaline hypophosphite, sodium borohydride and dimethyl-amino-boron.
The present invention provides a method of manufac-ture of contact switches having conductive coatings of increased adhesive strength and resolution for producing through-contacts in boreholes of printed circuit boards, com-prising the steps of providing a base material, drilling bore-holes in said material, cleaning, activating and reducing said base and producing a coating thereon, and heating-up said base material at temperatures within the range from 100°C to 150°C
immediately after said reducing step, said heating-up step being carried out for from 5 minutes to 2 hours, said reducing step being carried out by means of a reducing agent selected from the group consisting of alkaline hypophosphite, sodium borohydride and dimethyl-amino-boron.
Description
The present invention relates to a process ~or pro-ducing printed circuits with high occupation density and adhe-sive strength of the conductor paths.
Processes for producing printed circuits are known.
However, all such processes require pretreatment of the ini-tially non-conducting surface. ThiS is usually carried out by activating it by means of ionic, colloidal or sub-co:lloidal noble metal comp]exes and by subsequently treating it with a reducing agent. However, despite great advances and improve-ments, these proc:esses do not satisfy the requirement of caus-ing an integratecl bond of the metallic coating with the non-conducting surface, since there inherently occurs at best an occupation of the surface by chemical sorption.
Therefore, the present invention provides a process which permits an integrated composite bond of the metallic coating with the surface of the non-conductor and thus the production of extremely adhesive and edge-sharp conductor paths.
According to the present invention there is provided a method of manufacture of contact switches having conductive coatings of increased adhesive strength and resolutio~ for producing through--contacts in boreholes of printed circuit boards, comprising the steps of providing a base material, drilling boreholes in said material, cleaning, activating and reducing said base and producing a coating thereon, and heat-ing-up said base material at temperatures within the range from 100C to 150C immediately after said reducing step, said heating-up step being carried out for from 5 minutes to 2 hours, said reducing step being carried out by means of reduc-ing agent selected from t~e group consisting of alkaline hypophosphite, sodium borohydride and dimethyl-amino-boron.
Suitably the boards are heated preferably for about 30 4Z~Ei minutes.
In one embodiment of the present invention -the acti-vation is carrie~ out by ionic, colloidal or sub-colloidal noble-metal comp:Lexes or base-metal catalysts.
In another embodiment of the present invention the activation is carried out by means of an aqueous alkaline solution of a noble-metal complex, preferably of a palladium salt and 2-aminopyridine.
The process according to the present invention per-mits, in a novel way, the production of printed circuits with great adhesive strength and edge sharpness of the conductor paths which are intimately and composite-like bonded to the surface of the base material.
It is particularly advantageous that according to the process of the present invention not only can the surface of the uncoated or coated base material be metallized in the desired manner but that through-contacts of the boreholes of printed circuit boards which satisfy the highest requirements can also be produced.
The individual treatment steps in carrying out the process according to the present invention as far as prior to and after the heating step are conventional and, depending on the individual case, they can be carried out substantially unchanged by a person skilled in the art.
However, the favourable effects of the process according to the present invention can be fully displayed only when the heating step is carri.ed out immediately prior to or after the activation or after the reduction.
a2~
A repetition of the heating step after -the further trea-tment in the conventional desired manner, for example, after the lamination, exposure and development, can be of special ad-van-tage under certain conditions.
The heating step according -to the present invention can be carried out with conventional means such as in corresponding ovens or by means of infrared radiation, for example, drying by circulating air.
The large range of application of the process according to the present invention permits the use of any material including glass-fibre-reinforced epoxy resin, pnenol-resin paper, epoxy-resin paper, Plexiglas, polysulphone, polyimider polyamide, poly-7C/6~ o r o C2r~0n phenylene-oxide-PlYStYrene~ -flu~ydroc~rbon, polycarbollates, polyether imide and ceramic material.
Suitably -the coated base material is a substrate whose surface is provided with a firmly adhering layer which can be cured by heat and con-tains at least one substance selected from the group of modified rubber or synthetic rubber and being oxidizable or degradable by oxidizing agents. Alterna-tively the 20 base material is a substrate whose surface is coated with an agent, preferably copper, on one or both sides.
Therefore, the process according to the present inven-tion is applicable to all the conventional techniques, as for example, additive processes,subtractive processes and in selec-tive copper plating of soldering eyes and boreholes.
The products produced according to the present inventlon are used particuarly in electrical engineering and in electronics.
The process according to the present invention will be illustrated by the following Example:
30 Example A base material of glass-fibre-reinforced epoxy resin coated with adhesive is drilled and chemically and/or mechanically freed Erom bore dust. The board is caused -to swell in a solvent, rinsed wi-th water and solubilized in a chromium sulphuric acid (200 to 300 ml per li-tre oE 1-l2SO~, 10 to 100 g per li-tre oE CrO3).
This is followed by rinsing, detoxicating ancl rinsing. Activa-tion is then carried out in an ~R~gense activa-tor based on palla-dium, followed by rinsing, drying and reducing with a sodium boron hydride solution.
In a fur-ther s-tep heating is carried out~for 10 minutesJ
- to 140C. This is followed by coating with a photopolymer. The 10 next step is exposure to UV light, followed by development af-ter a reaction time in trichloroethane. The exposed circuit diagram to be metallized and the boreholes are once more selectively reduced. Copper is then buil-t up on conductor paths, soldering eyes and hole walls in an aqueous chemical copper bath.
After building up the desired copper layer the photo-polymer is stripped by treatment with methylene chloride.
After brushing the printed circuit board,it is provided with a soldering stop print and the soldering eyes and boreholes - are tinned while hot;
Processes for producing printed circuits are known.
However, all such processes require pretreatment of the ini-tially non-conducting surface. ThiS is usually carried out by activating it by means of ionic, colloidal or sub-co:lloidal noble metal comp]exes and by subsequently treating it with a reducing agent. However, despite great advances and improve-ments, these proc:esses do not satisfy the requirement of caus-ing an integratecl bond of the metallic coating with the non-conducting surface, since there inherently occurs at best an occupation of the surface by chemical sorption.
Therefore, the present invention provides a process which permits an integrated composite bond of the metallic coating with the surface of the non-conductor and thus the production of extremely adhesive and edge-sharp conductor paths.
According to the present invention there is provided a method of manufacture of contact switches having conductive coatings of increased adhesive strength and resolutio~ for producing through--contacts in boreholes of printed circuit boards, comprising the steps of providing a base material, drilling boreholes in said material, cleaning, activating and reducing said base and producing a coating thereon, and heat-ing-up said base material at temperatures within the range from 100C to 150C immediately after said reducing step, said heating-up step being carried out for from 5 minutes to 2 hours, said reducing step being carried out by means of reduc-ing agent selected from t~e group consisting of alkaline hypophosphite, sodium borohydride and dimethyl-amino-boron.
Suitably the boards are heated preferably for about 30 4Z~Ei minutes.
In one embodiment of the present invention -the acti-vation is carrie~ out by ionic, colloidal or sub-colloidal noble-metal comp:Lexes or base-metal catalysts.
In another embodiment of the present invention the activation is carried out by means of an aqueous alkaline solution of a noble-metal complex, preferably of a palladium salt and 2-aminopyridine.
The process according to the present invention per-mits, in a novel way, the production of printed circuits with great adhesive strength and edge sharpness of the conductor paths which are intimately and composite-like bonded to the surface of the base material.
It is particularly advantageous that according to the process of the present invention not only can the surface of the uncoated or coated base material be metallized in the desired manner but that through-contacts of the boreholes of printed circuit boards which satisfy the highest requirements can also be produced.
The individual treatment steps in carrying out the process according to the present invention as far as prior to and after the heating step are conventional and, depending on the individual case, they can be carried out substantially unchanged by a person skilled in the art.
However, the favourable effects of the process according to the present invention can be fully displayed only when the heating step is carri.ed out immediately prior to or after the activation or after the reduction.
a2~
A repetition of the heating step after -the further trea-tment in the conventional desired manner, for example, after the lamination, exposure and development, can be of special ad-van-tage under certain conditions.
The heating step according -to the present invention can be carried out with conventional means such as in corresponding ovens or by means of infrared radiation, for example, drying by circulating air.
The large range of application of the process according to the present invention permits the use of any material including glass-fibre-reinforced epoxy resin, pnenol-resin paper, epoxy-resin paper, Plexiglas, polysulphone, polyimider polyamide, poly-7C/6~ o r o C2r~0n phenylene-oxide-PlYStYrene~ -flu~ydroc~rbon, polycarbollates, polyether imide and ceramic material.
Suitably -the coated base material is a substrate whose surface is provided with a firmly adhering layer which can be cured by heat and con-tains at least one substance selected from the group of modified rubber or synthetic rubber and being oxidizable or degradable by oxidizing agents. Alterna-tively the 20 base material is a substrate whose surface is coated with an agent, preferably copper, on one or both sides.
Therefore, the process according to the present inven-tion is applicable to all the conventional techniques, as for example, additive processes,subtractive processes and in selec-tive copper plating of soldering eyes and boreholes.
The products produced according to the present inventlon are used particuarly in electrical engineering and in electronics.
The process according to the present invention will be illustrated by the following Example:
30 Example A base material of glass-fibre-reinforced epoxy resin coated with adhesive is drilled and chemically and/or mechanically freed Erom bore dust. The board is caused -to swell in a solvent, rinsed wi-th water and solubilized in a chromium sulphuric acid (200 to 300 ml per li-tre oE 1-l2SO~, 10 to 100 g per li-tre oE CrO3).
This is followed by rinsing, detoxicating ancl rinsing. Activa-tion is then carried out in an ~R~gense activa-tor based on palla-dium, followed by rinsing, drying and reducing with a sodium boron hydride solution.
In a fur-ther s-tep heating is carried out~for 10 minutesJ
- to 140C. This is followed by coating with a photopolymer. The 10 next step is exposure to UV light, followed by development af-ter a reaction time in trichloroethane. The exposed circuit diagram to be metallized and the boreholes are once more selectively reduced. Copper is then buil-t up on conductor paths, soldering eyes and hole walls in an aqueous chemical copper bath.
After building up the desired copper layer the photo-polymer is stripped by treatment with methylene chloride.
After brushing the printed circuit board,it is provided with a soldering stop print and the soldering eyes and boreholes - are tinned while hot;
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacture of contact switches hav-ing conductive coatings of increased adhesive strength and resolution for producing through-contacts in boreholes of printed circuit boards, comprising the steps of providing a base material, drilling boreholes in said material, cleaning, activating and reducing said base and producing a coating thereon, and heating-up said base material at temperatures within the range from 100°C to 150°C immediately after said reducing step, said heating-up step being carried out for from 5 minutes to 2 hours, said reducing step being carried out by means of a reducing agent selected from the group consisting of alkaline hypophosphate, sodium borohydride and dimethyl-amino-boron.
2. A process according to claim 1, in which the time of heating is about 30 minutes.
3. A process according to claim 1, in which the activation is carried out by ionic colloidal or sub-colloidal noble-metal complexes or base-metal catalysts.
4. A process according to claim 1, 2 or 3, in which the activation is carried out by means of an aqueous alkaline solution of a noble-metal complex.
5. A process according to claim 1, 2 or 3, in which the activation is carried out by means of an aqueous alkaline solution of a palladium salt and 2-aminopyridine.
6. A process according to claim 1, 2 or 3, in which the base material is selected from glass-fibre-reinforced epoxy resin, phenol-resin paper, epoxy-resin paper, Plexiglas, polysulphone, polyimide, polyamide, polyphenylene-oxide-polystyrene, fluorohydrocarbon, polycarbonates, polyether imide and ceramic material.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19843412447 DE3412447A1 (en) | 1984-03-31 | 1984-03-31 | METHOD FOR PRODUCING PRINTED CIRCUITS |
| DEP3412447.0 | 1984-03-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1224276A true CA1224276A (en) | 1987-07-14 |
Family
ID=6232515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000476796A Expired CA1224276A (en) | 1984-03-31 | 1985-03-18 | Process for producing printed circuits |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0156987A3 (en) |
| JP (1) | JPS60224292A (en) |
| AT (1) | AT392087B (en) |
| CA (1) | CA1224276A (en) |
| DE (1) | DE3412447A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3623505A1 (en) * | 1986-07-09 | 1988-01-21 | Deutsche Telephonwerk Kabel | METHOD FOR PRODUCING CIRCUIT BOARDS WITH GALVANIC LEAD-TIN LAYERS SELECTIVELY APPLIED ON THE SOLUTION EYES AND HOLE WALLS |
| DE3743780A1 (en) * | 1987-12-23 | 1989-07-06 | Bayer Ag | METHOD FOR IMPROVING THE ADHESIVITY OF CURRENTLY DEPOSITED METAL LAYERS ON POLYIMIDE SURFACES |
| JPH01195281A (en) * | 1988-01-28 | 1989-08-07 | Hitachi Chem Co Ltd | Catalyst for electroless plating |
| JPH0791657B2 (en) * | 1988-10-11 | 1995-10-04 | 上村工業株式会社 | Palladium activator and method for electroless plating of ceramic substrate |
| EP0367885A1 (en) * | 1988-11-08 | 1990-05-16 | Schering Aktiengesellschaft | Conditioning means for printed circuit boards |
| IT1232841B (en) * | 1989-02-03 | 1992-03-05 | Kemifar Spa | ACTIVATING COMPOSITION FOR THE METALLIZATION OF INSULATING SUBSTRATES AND METALIZATION PROCEDURE OF SUCH SUBSTRATES USING THE SAME |
| DE4417245A1 (en) * | 1994-04-23 | 1995-10-26 | Lpkf Cad Cam Systeme Gmbh | High resolution structured metallisation prodn. |
| JP4559936B2 (en) * | 2004-10-21 | 2010-10-13 | アルプス電気株式会社 | Electroless plating method and circuit forming method using this method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3772056A (en) * | 1971-07-29 | 1973-11-13 | Kollmorgen Photocircuits | Sensitized substrates for chemical metallization |
| DE2257378C3 (en) * | 1972-11-23 | 1980-05-08 | Dr. Hesse & Cie, 4800 Bielefeld | Process and means for the pretreatment of electrolessly metallized, non-conductive carrier surfaces |
| DE2538571A1 (en) * | 1975-08-29 | 1977-03-03 | Siemens Ag | METALIZATION METHOD OF THERMAL PLASTICS, IN PARTICULAR PHENOLIC RESINS |
| US4358479A (en) * | 1980-12-01 | 1982-11-09 | International Business Machines Corporation | Treatment of copper and use thereof |
| EP0102133A3 (en) * | 1982-03-26 | 1985-04-10 | General Electric Company | Metallized article composed of polyphenylene ether resin, high impact polystyrene, alumina and, optionally, a styrene-butadiene radial teleblock copolymer |
| DE3323476A1 (en) * | 1982-07-01 | 1984-01-05 | Kollmorgen Technologies Corp., 75201 Dallas, Tex. | IMPROVED METHOD FOR GALVANIC METAL DEPOSITION ON NON-METALLIC SURFACES |
| US4395313A (en) * | 1982-07-29 | 1983-07-26 | General Motors Corporation | Vacuum pretreatment process for durable electroplated coatings on ABS and PPO plastics |
-
1984
- 1984-03-31 DE DE19843412447 patent/DE3412447A1/en not_active Withdrawn
- 1984-12-15 EP EP84115541A patent/EP0156987A3/en not_active Withdrawn
-
1985
- 1985-03-18 CA CA000476796A patent/CA1224276A/en not_active Expired
- 1985-03-25 AT AT88385A patent/AT392087B/en not_active IP Right Cessation
- 1985-04-01 JP JP6673785A patent/JPS60224292A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60224292A (en) | 1985-11-08 |
| ATA88385A (en) | 1990-07-15 |
| AT392087B (en) | 1991-01-25 |
| EP0156987A2 (en) | 1985-10-09 |
| EP0156987A3 (en) | 1987-05-27 |
| DE3412447A1 (en) | 1985-11-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |