Claims
- 1. A method of assessing and restoring solderability of an electronic component, comprising the steps of:
- providing an electrolyte in an enclosed vessel having an inert atmosphere;
- placing in said electrolyte a cathode comprising a material having a hydrogen overvoltage at least as high as a solderable portion of the electronic component to minimize evolution of hydrogen from said electrolyte;
- placing said solderable portion of the electronic component in said electrolyte and in contact with said cathode;
- placing a counter electrode in contact with said electrolyte;
- passing an electric current between said cathode and said counter electrode;
- sequentially reducing metallic oxides present on said solderable portion of the component in said electrolyte and in contact with said cathode;
- measuring voltage and current as a function of time during said reduction of metallic oxides; and
- analyzing said voltage and current measurements to assess the solderability of the component.
- 2. The method of claim 1, wherein the step of measuring said voltage and current comprises measuring said voltage and current between said cathode and said counter electrode as a function of time.
- 3. The method of claim 1, further comprising the step of providing a third, reference electrode in contact with said electrolyte, and wherein the step of measuring said voltage and current as a function of time comprises measuring said current between said cathode and said counter electrode and said voltage between said cathode and said reference electrode.
- 4. The method of claim 1, wherein the step of analyzing said voltage and current measurements further comprises:
- comparing said measurements with predetermined baseline data from test specimens having known metallic oxides to identify metallic oxides present on said solderable portion of the electronic component;
- correlating said identified oxides on the electronic component with known solderability of said test specimens.
- 5. The method of claim 1, further comprising the step of selecting said cathode from the group of materials consisting of lead, tin, mercury, indium, antimony, tantalum, bismuth, arsenic, carbon, cadmium, thallium, and alloys thereof.
- 6. A method of assessing and restoring solderability of an electronic component by electrochemical reduction of metallic oxides on solderable portions of the component, comprising the steps of:
- providing an electrolyte in a reservoir having an atmosphere of inert gas;
- selecting a cathode from the group of materials consisting of lead, tin, mercury, indium, antimony, tantalum, bismuth, arsenic, carbon, cadmium, thallium, and alloys thereof, and further selecting said cathode to have a hydrogen overvoltage at least as high as the solderable portions of the electronic component to minimize evolution of hydrogen from said electrolyte;
- placing said cathode in said electrolyte;
- providing an inert electrode in contact with said electrolyte;
- placing the solderable portions of the component in contact with said electrolyte and said cathode;
- sequentially reducing the metallic oxides on the solderable portions of the component by passing a current between said cathode and said inert electrode;
- measuring voltage and current as a function of time during said sequential reduction of metallic oxides; and
- analyzing said voltage and current measurements to assess the solderability of the component.
- 7. The method of claim 6, wherein the measuring step comprises measuring said voltage and current between said cathode and said inert electrode as a function of time.
- 8. The method of claim 6, wherein the step of measuring said voltage and current as a function of time further comprises:
- placing said inert electrode in a compartment of said reservoir separated with a glass frit;
- placing a third, reference electrode in contact with said electrolyte in a second compartment of said reservoir separated with a second glass frit; and
- measuring said current between said cathode and said inert electrode and said voltage between said cathode and said reference electrode.
- 9. The method of claim 6, wherein the step of analyzing said voltage and current measurements further comprises:
- comparing said measurements with predetermined baseline data from test specimens having known metallic oxides to identify the metallic oxides on said solderable portions of the component; and
- correlating said identified oxides on the component with known solderability of said test specimens.
- 10. An apparatus for assessing and restoring solderability of an electronic component by electrochemical reduction of metallic oxides on solderable portions of the component, comprising:
- a reservoir containing an electrolyte in an atmosphere of inert gas;
- a cathode in contact with said electrolyte, said cathode comprising a material selected from the group of materials consisting of lead, tin, mercury, indium, antimony, tantalum, bismuth, arsenic, carbon, cadmium, thallium, and alloys thereof and having a hydrogen overvoltage at least as high as the solderable portions of the electronic component to minimize evolution of hydrogen from said electrolyte;
- an inert electrode in contact with said electrolyte;
- means placing the solderable portions of the component in contact with said electrolyte and said cathode;
- means for sequentially reducing the metallic oxides on the solderable portions of the component by passing a current between said cathode and said inert electrode;
- means for measuring voltage and current as a function of time during said sequential reduction of metallic oxides; and
- means for analyzing said voltage and current measurements to assess the solderability of the component.
- 11. The apparatus of claim 10, further comprising a third, reference electrode in contact with said electrolyte.
- 12. The apparatus of claim 11, further comprising first and second compartments separated from said reservoir by first and second glass frits, respectively, said inert electrode in contact with said electrolyte in said first compartment and said reference electrode in contact with said electrolyte in said second compartment.
- 13. The apparatus of claim 12, wherein said electrolyte comprises a borate buffer solution and said inert gas comprises argon.
RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 706,142 filed May 28, 1991, which issued on Nov. 16, 1993, as U.S. Pat. No. 5,262,022.
US Referenced Citations (14)
Non-Patent Literature Citations (2)
Entry |
Kolthoff et al, Polarography, 2d. ed., vol. 1, (1952), p. 395. |
Tench et al., "Electrochemical Assessment of Sn-Pb Solderability," Plating and Surface Finishing, pp. 44-46, Aug. 1990. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
706142 |
May 1991 |
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