GB2294476A - Method for decreasing the initiation time for an eletroless bath - Google Patents
Method for decreasing the initiation time for an eletroless bath Download PDFInfo
- Publication number
- GB2294476A GB2294476A GB9521107A GB9521107A GB2294476A GB 2294476 A GB2294476 A GB 2294476A GB 9521107 A GB9521107 A GB 9521107A GB 9521107 A GB9521107 A GB 9521107A GB 2294476 A GB2294476 A GB 2294476A
- Authority
- GB
- United Kingdom
- Prior art keywords
- noble metal
- metal solution
- treating
- ionic
- circuit board
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 20
- 230000000977 initiatory effect Effects 0.000 title claims description 13
- 230000003247 decreasing effect Effects 0.000 title claims description 6
- 229910000510 noble metal Inorganic materials 0.000 claims description 14
- 230000003197 catalytic effect Effects 0.000 claims description 12
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 11
- 229910052802 copper Inorganic materials 0.000 claims description 11
- 239000010949 copper Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 4
- 239000008367 deionised water Substances 0.000 claims description 4
- 229910021641 deionized water Inorganic materials 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 238000005507 spraying Methods 0.000 claims description 2
- 239000005751 Copper oxide Substances 0.000 claims 2
- 229910000431 copper oxide Inorganic materials 0.000 claims 2
- 238000000151 deposition Methods 0.000 claims 1
- 239000011347 resin Substances 0.000 description 16
- 229920005989 resin Polymers 0.000 description 16
- 238000007747 plating Methods 0.000 description 9
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 8
- 239000000243 solution Substances 0.000 description 7
- 239000002245 particle Substances 0.000 description 6
- 239000004020 conductor Substances 0.000 description 4
- 229910052763 palladium Inorganic materials 0.000 description 4
- 238000007772 electroless plating Methods 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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
- C23C18/30—Activating or accelerating or sensitising with palladium or other noble metal
-
- 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
-
- 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
- H05K2203/0703—Plating
- H05K2203/072—Electroless plating, e.g. finish plating or initial plating
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemically Coating (AREA)
- Manufacturing Of Printed Wiring (AREA)
Description
1 2294476 METHOD FOR DECREASING THE INITIATION TIME IN AN ELECTROLESS BATH
Field of the Invention
The present application is generally related to the field of metallizing substances, and more particularly to a process for decreasing the initiation time of an electroless bath plating solution.
Background of the Inventio
A process for selectively metallizing a circuit board is described in U.S. patent no. 5,162,144, (assigned to the same assignee as the present application) and hereby incorporated by reference. This process is used in conjunction with a dielectric layered, sequentially processed circuit board, as described in U.S. patent no. 5,260,170 (assigned to the same assignee as the present application). This circuit board process requires the sequential deposition and photo-definition of openings in two resins. The first resin, called resin A, is filled with a material referred to herein as a filler, which when activated, will promote electroless plating with a metal, the second resin, called resin B, does not contain such a filler. When each resin, in turn, is photochemically patterned, resin B over resin A, openings produced in resin B define areas called "channels"; superimposed openings produced in resin A and resin B define deeper areas called "wells" which open to a metal layer below. When this structure is subjected to processes which modify or activate particles contained in or at the surface of resin A, the channels and wells may be coated with an electroless plated metal to form metallic features, such as pads, vias and conductors.
In today's manufacturing environment reducing process throughput time is critical. After the particles are activated on the circuit board the electroless plating occurs. Electroless plating is normally characterized by an initiation time, defined as the time it takes the board to start plating once placed in the electroless bath. High activity electroless baths have a fast initiation time but can result in spurious plating. More stable bath chemistries result in longer initiation times. Further, it was found that longer initiation times result in a grainier deposit with less initiation and adhesive sites.
Thus there exists a need for a method to decrease the initiation time of a stable electroless bath. Further, there exists a need for a method which results in a better deposit.
DescriRtion of the Preferred Embodiments In producing a dielectric layered, sequentially processed circuit board, conductors, vias and pads are photochernically defined in the resins. This process exposes the resin A wherever a conductor, via or pad is required. Then the small metal oxide particles on the surface of resin A are exposed. The circuit board is then immersed (or sprayed) in a reducing solution, which produces small catalytic islands around the metal oxide particles. These islands have a thin layer of active metal. For instance in the preferred embodiment the metal oxide particles are Cu20- Once exposed to the reducing solution thin island layers of CuH, CuO or CuBHx form. Next, the board is placed in an electroless bath and solid copper formations appear where ever the catalytic islands occur in sufficient quantity.
The initiation time for a stable electroless bath can be as long as fifteen minutes. To decrease the initiation time a further step of immersing or spraying the circuit board with a noble metal salt solution occurs before electrolessly plating the circuit board. This results in a metal displacement reaction, in which the copper is replaced with the noble metal. This displacement only occurs in a thin layer on the top of the copper.
This layer of the noble metal is catalytic and also protects the copper based catalytic islands from oxidation. Since there are no oxides to remove, the electroless bath can start plating almost immediately. The copper oxides occur even if the board is immediately transferred to the electroless bath, but increase with any delay. Since the noble metal treatment maintains activity of all the catalytic film produced, control of catalytic film growth is essential -for maintaining selective plating. Growth of the catalytic film can be controlled by manipulation of the reduction solution concentrations and the reduction time.
EXAMPLES is 1. Samples of a two dielectric layered, sequentially processed circuit board produced according to U.S. patent no. 5,260,170 were prepared. The samples were reduced in a 1.0 molar borohydride and 0.25 molar EDTA solution for five minutes. The samples were then rinsed with deionized water. One sample was then placed in an ionic palladium solution for ten seconds. While, the second sample was dried an set aside. After the palladium dip the first sample was rinsed with deionized water. Both samples were then placed in a Shipley 4500 electroless copper bath for two minutes. The samples were then viewed with a scanning electron microscope.
The second sample showed only isolated plating, while the first sample was continuously plated.
2. A second sample of a two dielectric layered, sequentially processed circuit board produced according to U.S. patent no. 5,260,170 was prepared. The sample was exposed to the ionic palladium solution for ten seconds. Then the sample was rinsed in deionized water and placed in a Shipley 4500 electroless copper bath for two minutes. The sample was then viewed under a scanning electron microscope. The sample showed no plating had occurred. Enhanced plating is not due to adsorption of ionic palladium on the resin of the sample.
In summary, the present invention provides a method for decreasing the initiation time, increasing the density of adhesive sites and decreasing the particle size of the plated copper of conductors, pads and via on a circuit board.
Claims (7)
1. A method of decreasing the initiation time of copper-based catalytic film grown on a dielectric layered circuit board placed in an electroless bath, the method comprising the consecutive steps of:
producing copper-based catalytic islands from discrete copper oxide locations on or in a surface of a dielectric layer of the circuit board; rinsing the surface with deionized water; is treating the surface with an ionic noble metal solution; and rinsing unreacted noble metal solution off the surface before placing the circuit board in the electroless bath.
2. The method of claim 1, wherein the step of treating the surface with an ionic noble metal solution includes the sub-step of selectively depositing a thin layer of noble metal onto areas covered by the copperbased catalytic islands via an electrochemical displacement of reduced copper on the surface of the catalytic islands.
3. The method of claim 1, wherein the step of treating the surface with an ionic noble metal solution includes the sub-step of immersing the surface in the ionic noble metal solution.
4. The method of claim 1, wherein the step of treating the surface with an ionic noble metal solution includes the sub-step of immersing the surface in the ionic noble metal solution for preferably two minutes.
5. The method of claim 1, wherein the step of treating the.surface with an ionic noble metal solution includes the sub-step of spraying the surface with the ionic noble metal solution.
6. The method of claim 1 wherein the step of producing copperbased catalytic islands includes the sub-steps of:
exposing the discrete copper oxide locations on the surface; and treating the surface with a reduction solution, thereby producing an active metal layer.
7. A circuit board with selectively deposited electroless copper produced in accordance with any one of the methods as defined in claims 1 through 6.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US33047394A | 1994-10-28 | 1994-10-28 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9521107D0 GB9521107D0 (en) | 1995-12-20 |
| GB2294476A true GB2294476A (en) | 1996-05-01 |
| GB2294476B GB2294476B (en) | 1998-03-11 |
Family
ID=23289937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9521107A Expired - Fee Related GB2294476B (en) | 1994-10-28 | 1995-10-16 | Method for decreasing the initiation time in an electroless bath |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPH08213738A (en) |
| KR (1) | KR960014396A (en) |
| DE (1) | DE19540122C2 (en) |
| FR (1) | FR2726205B1 (en) |
| GB (1) | GB2294476B (en) |
| TW (1) | TW293984B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0726697A3 (en) * | 1995-01-30 | 1998-01-07 | Nec Corporation | Improved printed wiring board and method for preparing the same |
| EP1878812A4 (en) * | 2005-03-11 | 2008-10-29 | Hitachi Chemical Co Ltd | PROCESS FOR TREATING A SURFACE OF COPPER AND COPPER |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1003575A (en) * | 1962-04-19 | 1965-09-08 | Sperry Gyroscope Co Ltd | Chemical plating process |
| GB1079460A (en) * | 1965-06-30 | 1967-08-16 | Ibm | Improvements in and relating to the electroless deposition of magnetic materials |
| GB1322081A (en) * | 1970-06-03 | 1973-07-04 | Shipley Co | Electroless nickel solution |
| GB1360592A (en) * | 1973-02-14 | 1974-07-17 | Rca Corp | Electroless cobalt plating bath |
| US3857724A (en) * | 1971-08-20 | 1974-12-31 | Ibm | Primer for electroless plating |
| EP0321067A1 (en) * | 1987-12-14 | 1989-06-21 | Hitachi Chemical Co., Ltd. | Process for treating copper surface |
| EP0221359B1 (en) * | 1985-10-29 | 1989-07-26 | International Business Machines Corporation | A process for accelerating pd/sn seeds for electroless copper plating |
| US5110633A (en) * | 1989-09-01 | 1992-05-05 | Ciba-Geigy Corporation | Process for coating plastics articles |
| WO1993002847A1 (en) * | 1991-08-01 | 1993-02-18 | Motorola, Inc. | Process for metallizing substrates using starved-reaction metal-oxide reduction |
| US5212138A (en) * | 1991-09-23 | 1993-05-18 | Applied Electroless Concepts Inc. | Low corrosivity catalyst for activation of copper for electroless nickel plating |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2939804A (en) * | 1958-01-23 | 1960-06-07 | Uarco Inc | Resin particle coated with metal |
| EP0530144A3 (en) * | 1991-08-23 | 1994-08-24 | Ciba Geigy Ag | Process for metallising plastic articles |
-
1995
- 1995-10-02 FR FR9511552A patent/FR2726205B1/en not_active Expired - Fee Related
- 1995-10-06 TW TW084110519A patent/TW293984B/zh active
- 1995-10-16 GB GB9521107A patent/GB2294476B/en not_active Expired - Fee Related
- 1995-10-19 KR KR1019950036104A patent/KR960014396A/en not_active Ceased
- 1995-10-24 JP JP7298869A patent/JPH08213738A/en active Pending
- 1995-10-27 DE DE19540122A patent/DE19540122C2/en not_active Expired - Fee Related
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1003575A (en) * | 1962-04-19 | 1965-09-08 | Sperry Gyroscope Co Ltd | Chemical plating process |
| GB1079460A (en) * | 1965-06-30 | 1967-08-16 | Ibm | Improvements in and relating to the electroless deposition of magnetic materials |
| GB1322081A (en) * | 1970-06-03 | 1973-07-04 | Shipley Co | Electroless nickel solution |
| US3857724A (en) * | 1971-08-20 | 1974-12-31 | Ibm | Primer for electroless plating |
| GB1360592A (en) * | 1973-02-14 | 1974-07-17 | Rca Corp | Electroless cobalt plating bath |
| EP0221359B1 (en) * | 1985-10-29 | 1989-07-26 | International Business Machines Corporation | A process for accelerating pd/sn seeds for electroless copper plating |
| EP0321067A1 (en) * | 1987-12-14 | 1989-06-21 | Hitachi Chemical Co., Ltd. | Process for treating copper surface |
| US5110633A (en) * | 1989-09-01 | 1992-05-05 | Ciba-Geigy Corporation | Process for coating plastics articles |
| WO1993002847A1 (en) * | 1991-08-01 | 1993-02-18 | Motorola, Inc. | Process for metallizing substrates using starved-reaction metal-oxide reduction |
| US5212138A (en) * | 1991-09-23 | 1993-05-18 | Applied Electroless Concepts Inc. | Low corrosivity catalyst for activation of copper for electroless nickel plating |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0726697A3 (en) * | 1995-01-30 | 1998-01-07 | Nec Corporation | Improved printed wiring board and method for preparing the same |
| EP1878812A4 (en) * | 2005-03-11 | 2008-10-29 | Hitachi Chemical Co Ltd | PROCESS FOR TREATING A SURFACE OF COPPER AND COPPER |
| US7588835B2 (en) | 2005-03-11 | 2009-09-15 | Hitachi Chemical Company, Ltd. | Method of treating the surface of copper and copper |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19540122A1 (en) | 1996-05-02 |
| FR2726205B1 (en) | 1997-09-26 |
| KR960014396A (en) | 1996-05-22 |
| JPH08213738A (en) | 1996-08-20 |
| GB2294476B (en) | 1998-03-11 |
| DE19540122C2 (en) | 1997-08-21 |
| TW293984B (en) | 1996-12-21 |
| FR2726205A1 (en) | 1996-05-03 |
| GB9521107D0 (en) | 1995-12-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20001016 |