Predeposited transient phase electronic interconnect media

• US 5,964,395 A
• Filed: 06/09/1997
• Issued: 10/12/1999
• Est. Priority Date: 06/09/1997
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Glovatsky, Andrew Z., Paruchuri, Mohan R.
• Primary Examiner(s): Ryan, Patrick
• Assistant Examiner(s): STONER, KILEY SHAWN
• Application Number:
  US08/868,846
• Time in Patent Office: 855 Days
• Field of Search: 228/254, 228/258, 228/262, 228/180.21, 228/261, 228/123.1, 427/96
• US Class Current: 228/123.1
• CPC Class Codes: B23K 35/0222 for use in soldering, brazing B23K35/0205 takes precedence
• CPC Class Codes: B23K 35/26 with the principal constituent melting at less than 400 degrees C
• CPC Class Codes: C23C 26/02 applying molten material to the substrate
• CPC Class Codes: C23C 4/00 Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge build-up welding B23K, e.g. B23K5/18, B23K9/04
• CPC Class Codes: H05K 2201/0373 Conductors having a fine structure, e.g. providing a plurality of contact points with a structured tool providing micro- or nanometer scale roughness on a metal surface H05K2203/0307
• CPC Class Codes: H05K 2203/0495 Cold welding
• CPC Class Codes: H05K 3/328 by welding
• CPC Class Codes: H05K 3/3463 Solder compositions in relation to features of the printed circuit board or the mounting process

Abstract

A method of attaching an electronic component to a substrate comprising the steps of depositing a spray metal coating atop a substrate. An electronic component is placed atop a coating. A liquid metal is dispensed on or near the component. The liquid metal wets the component and the coating. The metal is reacted with the coating to form an electrically conductive bond with the substrate and adheres the component to the substrate. The reactive metal may be heated to a temperature which makes it liquid and facilitates wetting the coating and component. Suitable materials for the spray metal coating include copper, nickel, tin, bismuth, lead and silver and mixtures thereof. Suitable liquid metals generally include low melting temperature metals such as gallium and indium and mixtures thereof.

Claims

1. A method of attaching an electronic component to a substrate comprising the steps of:

depositing a metal coating atop a substrate;

adding a filler to said deposited metal coating and then removing said filler from said metal coating, whereby said metal coating is between 10 and 75% void after said filler is removed;

placing an electronic component atop said coating;

dispensing a liquid metal near said component, said liquid metal wetting said component and said coating;

reacting said metal with said coating to form an electrically conductive bond between said substrate and said component.

2. A method of attaching an electronic component to a metal electrical circuit comprising the steps of:

depositing a coating of a thermal spray metal and a filler atop selected areas of said circuit, said filler comprising between 10-70% of said coating;

removing said filler from said coating whereby said coating is between 10-70% void;

placing an electronic component atop said coating;

heating a reactive metal to a liquid state;

dispensing said liquid metal near said component, said liquid metal wetting said component and penetrating said coating;

reacting said liquid metal with said coating to form an electrically conductive bond between said circuit and said component.

3. The method of claim 2, wherein said spray metal is selected from the group comprising Cu, Ni, Sn, Pb and Ag and combinations thereof.

4. The method of claim 2, wherein said liquid metal is selected from Ga and alloys of Bi, In and Sn.