Metal fusion bonding – Process – Plural joints
Patent
1994-06-16
1996-10-29
Heinrich, Samuel M.
Metal fusion bonding
Process
Plural joints
228105, 228212, H05K 334
Patent
active
055688926
ABSTRACT:
A method for aligning and soldering a first device (11) to a substrate (16) comprises the steps of providing a plurality of solder elements (17) between the first device and the substrate, aligning the first device, and then reflowing and cooling the solder elements to bond the first device to the substrate. The improvement comprises, first, reflowing only a first group of solder elements and then cooling the elements of the first group, thereby to tack the first device to the substrate. Thereafter, we reflow only a second group of the plurality of solder elements and cool the second group, thereby to provide a more secure bond between the device and the substrate without interfering with the alignment of the first device. This method reduces the amount of energy needed for each reflow step, thereby reducing stresses and maintaining better alignment. In an illustrative embodiment, three groups of solder elements are provided, each group containing four solder elements to be heated by individual heater elements (39). Separate circuits (27, 28, 29) are provided for energizing sequentially the three groups for reflow. Thus, four solder elements are initially reflowed and cooled to provide good tacking between the first device and the substrate. Thereafter, the other groups are actuated sequentially with heat dissipation occurring between each successive actuation. Thermal barriers (34, 38) are preferably included between each heater element and the first device and between the heater element and the substrate to concentrate heat on the solder element (17). The first device is illustratively a laser (11) that is aligned with an optical fiber (12) prior to bonding.
REFERENCES:
patent: 3384958 (1968-05-01), Christian et al.
patent: 3486223 (1969-12-01), Butera
patent: 3660632 (1972-05-01), Leinkram
patent: 4119363 (1978-10-01), Camlibel et al.
patent: 4728787 (1988-03-01), Henry et al.
patent: 4807956 (1989-02-01), Tournereau et al.
patent: 5024504 (1991-06-01), Boudreau et al.
patent: 5042709 (1991-08-01), Cina et al.
patent: 5090116 (1992-02-01), Henschen et al.
patent: 5249733 (1993-10-01), Brady et al.
patent: 5307434 (1994-04-01), Blonder et al.
patent: 5384873 (1995-01-01), Chun et al.
Research Disclosure, "Repair Technique for Area Array Solder Interconnections", Kenneth Mason Publications Ltd, England, Jun. 1991, No. 326.
European Patent Application-EP-A-O 439 (AT&T Co.) 19 Jan. 1994. Application No. 93305295.3, filing date Jul. 6, 1993. Int. Cl. G02B 6/42.
Advances in Electronic Packaging 1993; Proceedings of the 1993 ASME International Electronics Packaging Conference; vol. 2, pp. 1149-1155; N. Basavanhally: "Application of soldering technologies for opto-electronic component assembly".
SPIE vol. 703 Integration and Packaging of Optoelectronic Devices (1986), pp. 42-47. S. Enochs: "A packaging technique to achieve stable single-mode fiber to laser alignment".
Anderson Roderick B.
Heinrich Samuel M.
Lucent Technologies - Inc.
Williams Vernon E.
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