Ultrasonic laser soldering
AssigneeHughes Aircraft Company
InventorPeter W. Bullock
Life of this patent
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Abstract
Laser soldering in a tape automated bonding procedure is carried out on outer ends of a number of high density leads (72) printed on a film (78) of mylar and having inner ends connected to a circuit chip (70). The outer ends of the leads are soldered, without the use of flux, by application of heat and ultrasonic energy in a timed program while pressing an end (52) of the lead to be soldered against the substrate pad to which it is to be soldered. An elongated ultrasonically vibratable capillary (16) is employed to press the wire down against its pad (54) and to receive and guide an optical fiber (44) through which a beam of laser energy is fed coaxially through the capillary (16) to heat the wire end (52).
Claims21
A method of bonding first and second members to each other comprising the steps of:
- pressing the members against one another at an area thereof to be bonded,
- applying heat energy to one of the members at said area by directing a laser beam at said one of said members, and
- applying sonic energy to one of the members at said area.
Apparatus for soldering a lead to a substrate comprising:
- a pressure tool having a pressure tip for pressing against a lead,
- means for vibrating the tool at an ultrasonic frequency,
- means for projecting a laser beam at a lead at said pressure tip, and
- means for moving the tool to press said tip against said lead.
A method of soldering of first and second pretinned members without the use of flux comprising the steps of:
- pressing the members together at a common area to be soldered, and
- applying a timed program of heat energy and ultrasonic energy to one of the members.
A wire bonder comprising:
- a support,
- a worktable connected to the support for carrying an object to which a wire is to be bonded,
- a bonder frame,
- means for mounting the frame to the support for motion in a first direction toward and away from the worktable,
- motor means for driving the frame in said direction,
- a transducer support,
- an ultrasonic transducer carried on said support,
- a bonder tool connected to the transducer for movement therewith, said tool comprising a capillary having a solid pressure tip for pressing a lead to be bonded against an object on the worktable, said capillary having a bore extending to the tip, said tip being transparent to laser energy,
- means for mounting the transducer support to the bonder frame for motion relative to the bonder frame in said direction,
- an optical fiber positioned in the bore and having a fiber end at said pressure tip, and
- a laser having a laser beam output connected to said optical fiber.
A method of bonding first and second solder-coated members to each other comprising the steps of:
- pressing the members against one another at an area thereof to be bonded,
- applying heat energy to one of the members at said area by directing a laser beam directly at said one member,
- applying sonic energy to one of the members at said area, and
- separating the members from one another after application of heat energy, so as to allow the solder coating to flow between the members.
Dependencies are inferred from the claim text.