US3666527A - Method of electroless deposition of metals with improved sensitizer - Google Patents

Method of electroless deposition of metals with improved sensitizer Download PDF

Info

Publication number
US3666527A
US3666527A US60091A US3666527DA US3666527A US 3666527 A US3666527 A US 3666527A US 60091 A US60091 A US 60091A US 3666527D A US3666527D A US 3666527DA US 3666527 A US3666527 A US 3666527A
Authority
US
United States
Prior art keywords
solution
plating
ion
sensitizing
metal
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 - Lifetime
Application number
US60091A
Other languages
English (en)
Inventor
Nathan Feldstein
Thomas Stephen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Application granted granted Critical
Publication of US3666527A publication Critical patent/US3666527A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • C23C18/285—Sensitising or activating with tin based compound or composition

Definitions

  • Certain metals can be plated on non-metallic surfaces by an autocatalytic electroless process in which the surface is first treated with a sensitizing solution, then with an activating solution which precipitates nucleating centers.
  • ceramics and many synthetic resins can be provided with coatings of nickel or copper, for example, which may or may not be later covered with a heavier layer of metal by electroplating.
  • the sensitizing solution most commonly used in the past contains Sn+ ions generally formed from the salt stannous chloride. This material has proved to be quite satisfactory for electroless plating of metals on most nonmet-allic materials. However, there are certain plastics, such as Teflon, Lucite and silicone rubbers, as well as certain commercial photoresists, which cannot be satisfactorily plated by this method. The reason for the difficulty appears to be that these materials are unusually smooth and non-porous and are not readily wetted by aqueous solutions of stannous salts.
  • One object of the present invention is to provide an improved method of autocatalytically electrolessly depositing metals on certain non-metallic substrates which are difiicult to wet.
  • Another object of the invention is to provide an improved sensitizing solution for autocatalytically electrolessly depositing metals on non-metallic substrates.
  • the plate is permitted to remain in the plating bath until either a good uniform plating is obtained or it is apparent that no further deposit is being obtained on unplated areas. This is usually a few minutes.
  • the following table shows the effect of adding varying amounts of SnCL, solution to a conventional SnCl sensitizing solution.
  • the SnCl, stock solution was prepared by dissolving crystalline material in water and permitting the solution to stand for about one week at room temperature before using. It has been found that an aging effect, not fully understood, occurs in this solution. Less of the aged solution is required to impart the improved wetting to the sensitizer. The aging efiect may be due to an hydrolysis reaction taking place.
  • Example II With all conditions and treating and plating solutions remaining the same as in Example I except the proportion of stannic ion, Mylar tape coated with AZ-l350, a positive acting photoresist, was plated with nickel from the same nickel-boron bath. In this case, when the concentration of stannic ion was above zero and up to '7.5X10- moles/liter, only patchy plating was obtained. Above about 1.25 X moles/liter good plating was obtained although this increase in coverage was again gradual. With no stannic ion added, only little plating was obtained.
  • Example III In another test run using a nickel-boron plating bath, as described in Example I, on AZ-1350 photoresist, the sensitizing solution was made up by adding varying amounts of powdered SnCl -5-H O (reagent grade) to freshly prepared SnCl solution.
  • the stock solution from which the stannous ion solution was prepared comprised 214 gms. SnCl -2H O (Baker reagent grade) and 290 cc. conc. HCl.
  • the actual solution used for the run contained 64x10 molar concentration of Sn+ ion and an HCl content of 0.19 M.
  • Example IV iWith conditions otherwise the same as in Example HI, the molar concentrations of Sn+ ion used was increased to 12.8Xl0- molar and the HCl to 0.38 Patchy plating on AZ-1350 photoresist from the same nickelboron plating bath was obtained using molar concentration of Sn+ ion below about 10.4)(10' molar. Good, uniform plating was obtained above about 104x10 molar.
  • the copper plating bath had the following composition.
  • E.D.T.A. Ethylene diaminetetra-acetic acid (40% solution of the sodium salt) -gm-s 36.5
  • the sensitizing solution contained Sn+ ion 6.4X10- molar and had an HCl content of 0.19 molar. To this was added varying amounts of stannic chloride solution that had been aged for a minimum of one week.
  • Example VI Using the same copper-depositing bath as in Example V and Sn+ ion concentration of 6.4X10- moles, an experimental run was made to see if the quality of the plating was affected by using increasingly high ratios of Sn ion to Sn+ ion, with the following results.
  • the substrate used was Teflon.
  • stannic ion may be generated.
  • agents capable of oxidizing the Sn ion to Sn ion such as iodine or permangauates, for example.
  • Another method is by exposing the Sn+ solution to U.V. light for a period of time. By merely heating the Sn+ solution in air, some of the Sn ion is converted to Su
  • the addition of Sn ion is preferred because the amount can be more accurately controlled and can conveniently be used in production facilities.
  • the pH of the solutions was generally below one and the solutions were clear. At pH values around 1.5 the solutions become turbid. It is therefore preferred that the pH value he kept below about 1.5 and, more preferably, below one.
  • a molar ratio of divalent tin ion to tetravalent tin ion between about 1:1 and 1000:1 has been found to be operative.
  • stanic chloride is given as an example of a suitable tin compound to use to add So ion in the present invention, it will be understood that other soluble stannic compounds can be used.
  • the improved method of the present invention is also of particular interest in the making of printed circuit boards; especially boards having small-diameter through holes which must be plated with metal.
  • Materials commonly used for printed circuit substrates are phenolic resinimpregnated fibrous materials, epoxy resin-impregnated boards and glass fiber-epoxy resin boards.
  • the boards are usually laminates of several thin sheets.
  • the improved sensitizers described herein wet these materials very well. The sensitizers wet so efliciently that very small diameter through holes, usually very diflicult to plate electrolessly with previously used Sn+ sensitizers, can now be plated very well.
  • the improvement is due not only to the increased wetting ability of the present sensitizers but also due to the fact that they are not degraded by air agitation. Agitation of the bath is necessary to cause solutions to flow through the holes. Air agitation adversely affects Sn+ sensitizers.
  • a method for electrolessly plating a surface with a metal comprising the steps of sensitizing the surface with a sensitizing solution made by mixing separate sources of divalent tin ion and tetravalent tin ion in a molar ratio from about 1:1 to about 1000: 1, the solution having a pH lower than about 1.5, the tetravalent tin ion being prepared as a separate solution of a stannic salt which is aged for a time before combining it with the source of divalent tin ion, treating the sensitized surface with a catalyzing solution so as to provide catalytic nucleating centers thereon, and plating said metal on the catalyzing surface by contacting the surface with an electroless metal plating bath.
  • said surface is a smooth, dense, difficultly wettable plastic.

Landscapes

  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemically Coating (AREA)
US60091A 1970-07-31 1970-07-31 Method of electroless deposition of metals with improved sensitizer Expired - Lifetime US3666527A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US6009170A 1970-07-31 1970-07-31

Publications (1)

Publication Number Publication Date
US3666527A true US3666527A (en) 1972-05-30

Family

ID=22027287

Family Applications (1)

Application Number Title Priority Date Filing Date
US60091A Expired - Lifetime US3666527A (en) 1970-07-31 1970-07-31 Method of electroless deposition of metals with improved sensitizer

Country Status (7)

Country Link
US (1) US3666527A (cg-RX-API-DMAC10.html)
JP (1) JPS5223982B1 (cg-RX-API-DMAC10.html)
CA (1) CA945838A (cg-RX-API-DMAC10.html)
DE (1) DE2137179A1 (cg-RX-API-DMAC10.html)
FR (1) FR2104816B1 (cg-RX-API-DMAC10.html)
GB (1) GB1348793A (cg-RX-API-DMAC10.html)
NL (1) NL7110561A (cg-RX-API-DMAC10.html)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3877965A (en) * 1970-09-28 1975-04-15 Rohm & Haas Conductive nylon substrates and method of producing them
US3982054A (en) * 1972-02-14 1976-09-21 Rca Corporation Method for electrolessly depositing metals using improved sensitizer composition
US3993801A (en) * 1975-02-18 1976-11-23 Surface Technology, Inc. Catalytic developer
US4082899A (en) * 1976-09-07 1978-04-04 Nathan Feldstein Method of applying catalysts for electroless deposition and article
DE2856375A1 (de) * 1977-12-28 1979-08-02 Cbs Sony Records Inc Verfahren zur herstellung von schallplattenmatrizen
US4301190A (en) * 1978-08-17 1981-11-17 Nathan Feldstein Pretreatment with complexing agent in process for electroless plating
US4396643A (en) * 1981-06-29 1983-08-02 Minnesota Mining And Manufacturing Company Radiation absorbing surfaces
US4398462A (en) * 1979-05-30 1983-08-16 Tdk Electronics Co., Ltd. Hot melt screen printing machine
US4582885A (en) * 1978-07-20 1986-04-15 Minnesota Mining And Manufacturing Company Shaped plastic articles having replicated microstructure surfaces
US4582111A (en) * 1981-06-29 1986-04-15 Minnesota Mining And Manufacturing Company Radiation absorbing surfaces
US4853320A (en) * 1987-09-16 1989-08-01 U.S. Philips Corporation Method of locally providing metal on a surface of a substrate
US5403650A (en) * 1982-04-27 1995-04-04 Baudrand; Donald W. Process for selectively depositing a nickel-boron coating over a metallurgy pattern on a dielectric substrate and products produced thereby
US20110105366A1 (en) * 2007-06-18 2011-05-05 Illumina, Inc. Microfabrication methods for the optimal patterning of substrates

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3245826A (en) * 1963-06-12 1966-04-12 Clevite Corp Magnetic recording medium and method of manufacture
US3573973A (en) * 1967-11-13 1971-04-06 Ibm High speed additive circuit process
DE1905097A1 (de) * 1969-02-01 1970-08-06 Dynamit Nobel Ag Verfahren zur Metallisierung von Kunststoffen

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3877965A (en) * 1970-09-28 1975-04-15 Rohm & Haas Conductive nylon substrates and method of producing them
US3982054A (en) * 1972-02-14 1976-09-21 Rca Corporation Method for electrolessly depositing metals using improved sensitizer composition
US3993801A (en) * 1975-02-18 1976-11-23 Surface Technology, Inc. Catalytic developer
US4082899A (en) * 1976-09-07 1978-04-04 Nathan Feldstein Method of applying catalysts for electroless deposition and article
DE2856375A1 (de) * 1977-12-28 1979-08-02 Cbs Sony Records Inc Verfahren zur herstellung von schallplattenmatrizen
US4582885A (en) * 1978-07-20 1986-04-15 Minnesota Mining And Manufacturing Company Shaped plastic articles having replicated microstructure surfaces
US4301190A (en) * 1978-08-17 1981-11-17 Nathan Feldstein Pretreatment with complexing agent in process for electroless plating
US4398462A (en) * 1979-05-30 1983-08-16 Tdk Electronics Co., Ltd. Hot melt screen printing machine
US4396643A (en) * 1981-06-29 1983-08-02 Minnesota Mining And Manufacturing Company Radiation absorbing surfaces
US4582111A (en) * 1981-06-29 1986-04-15 Minnesota Mining And Manufacturing Company Radiation absorbing surfaces
US5403650A (en) * 1982-04-27 1995-04-04 Baudrand; Donald W. Process for selectively depositing a nickel-boron coating over a metallurgy pattern on a dielectric substrate and products produced thereby
US5565235A (en) * 1982-04-27 1996-10-15 Baudrand; Donald W. Process for selectively depositing a nickel-boron coating over a metallurgy pattern on a dielectric substrate
US4853320A (en) * 1987-09-16 1989-08-01 U.S. Philips Corporation Method of locally providing metal on a surface of a substrate
US20110105366A1 (en) * 2007-06-18 2011-05-05 Illumina, Inc. Microfabrication methods for the optimal patterning of substrates
US9677194B2 (en) 2007-06-18 2017-06-13 Illumina, Inc. Microfabrication methods for the optimal patterning of substrates

Also Published As

Publication number Publication date
FR2104816B1 (cg-RX-API-DMAC10.html) 1975-08-29
GB1348793A (en) 1974-03-20
CA945838A (en) 1974-04-23
NL7110561A (cg-RX-API-DMAC10.html) 1972-02-02
AU3126671A (en) 1973-01-18
FR2104816A1 (cg-RX-API-DMAC10.html) 1972-04-21
DE2137179A1 (de) 1972-02-03
JPS5223982B1 (cg-RX-API-DMAC10.html) 1977-06-28

Similar Documents

Publication Publication Date Title
US3011920A (en) Method of electroless deposition on a substrate and catalyst solution therefor
US3095309A (en) Electroless copper plating
US3962494A (en) Sensitized substrates for chemical metallization
US4021314A (en) Method of depositing a metal on a surface
US3403035A (en) Process for stabilizing autocatalytic metal plating solutions
US4424241A (en) Electroless palladium process
US3033703A (en) Electroless plating of copper
US3745039A (en) Electroless cobalt plating bath and process
US3666527A (en) Method of electroless deposition of metals with improved sensitizer
US4684550A (en) Electroless copper plating and bath therefor
US4639380A (en) Process for preparing a substrate for subsequent electroless deposition of a metal
EP0288491A1 (en) SELECTIVE METALLIZATION PROCESS, ADDITIVE PROCESS FOR THE MANUFACTURE OF PRINTED CICRUIT PLATES, AND COMPOSITION USED.
US4525390A (en) Deposition of copper from electroless plating compositions
US3075855A (en) Copper plating process and solutions
US4199623A (en) Process for sensitizing articles for metallization and resulting articles
US3993801A (en) Catalytic developer
US4181760A (en) Method for rendering non-platable surfaces platable
US4150171A (en) Electroless plating
US3853590A (en) Electroless plating solution and process
US3436233A (en) Method and composition for autocatalytically depositing copper
US4167601A (en) Method of depositing a stress-free electroless copper deposit
US4325990A (en) Electroless copper deposition solutions with hypophosphite reducing agent
US3900599A (en) Method of electroless plating
US3423226A (en) Plating of non-metallic bodies
US3674550A (en) Method of electroless deposition of a substrate and sensitizing solution therefor