Claims
- 1. A method of joining at least two microelectronic components to one another comprising the steps of connecting the components to be joined with a ternary solder alloy consisting essentially of tin of at least about 70 weight percent, a selectively limited amount of silver from about 6.5 to about 7.5 weight percent, balance indium.
- 2. A method as defined in claim 1 wherein said solder alloy consists essentially of from about 70.5 to 73.5 weight percent tin, from about 6.5 to about 7.5 weight percent silver, balance indium.
- 3. A method as defined in claim 2 wherein said solder alloy consists essentially of about 73.2 weight percent tin, about 6.5 weight percent silver, balance indium.
- 4. A process for producing circuit boards, comprising the steps of:
- producing plated through holes in a circuit board;
- inserting the pins of pin-in-hole components into the plated through holes;
- producing a stationary wave of liquid solder consisting essentially of tin of at least about 70% by weight, an amount of silver selectively limited to between about 6.5 and about 7.5% by weight and with the balance indium;
- moving the circuit board across the wave with the bottom of the circuit board in contact with the wave, thereby substantially filling the plated through holes with solder; and
- cooling the circuit board to form solid solder joints.
- 5. A process for producing circuit boards comprising the steps of:
- producing a substrate with multiple wiring layers including exposed metal pads on a surface;
- forming a solder paste comprising a flux, an organic vehicle and particles of metal consisting essentially of tin of at least about 70% by weight, an amount of silver selectively limited to between about 6.5 and about 7.5% by weight and with the balance indium;
- depositing the solder paste upon said substrate;
- placing terminals of a surface mount component onto corresponding pads of the substrate;
- heating said solder paste to a temperature sufficient to reflow the solder paste to connect the component with the substrate; and cooling to solidify the connections.
Parent Case Info
This is a Division of Ser. No. 08/768,907 filed Dec. 17, 1996, now U.S. Pat. No. 5,874,043 provisional application No. 60/019,589 filed Jun. 12, 1996.
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Divisions (1)
|
Number |
Date |
Country |
Parent |
768907 |
Dec 1996 |
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