At&t Bell Laboratories

Other

Lucent Technologies Inc.

Yiu-Man Wong

King Lien Tai

Hung N Nguyen

Avishay Katz

Chien-Hsun Lee

Leroy D L'Esperance, Iii

John William Osenbach

Gustav Edward Derkits, Jr

David Gerald Coult

Donlad D Bacon

An improved method and composition for achieving a kinetically-controlled solder bond is disclosed having particular application to the fabrication of hybrid integrated circuits and optical subassemblies. The method involves the use of a solder layer, a quenching layer, and a control layer disposed between the solder layer and quenching layer, in which the control layer is advantageously comprised of a thin film of platinum. Additionally, a barrier layer, also preferably comprised of a thin film of platinum, is disposed between the solder layer and the parts to be bonded to prevent the oxidation of solder materials during the soldering process or later storage of the soldered parts.

Method and compositions for achieving a kinetically controlled solder

A laser device is bonded to a diamond submount by means of a procedure including (1) codepositing an auxiliary layer, on a layer of barrier metal that has been deposited overlying the submount, followed by (2) depositing a wetting layer on the auxiliary layer, and (3) by depositing a solder layer comprising alternating metallic layers, preferably of gold and tin sufficient to form an overall tin-rich gold-tin eutectic composition. The barrier metal is typically W, Mo, Cr, or Ru. Prior to bonding, a conventional metallization such as Ti-Pt-Au (three layers) is deposited on the laser device's bottom ohmic contact, typically comprising Ge. Then, during bonding, the solder layer is brought into physical contact with the laser device's metallization under enough heat and pressure, followed by cooling, to form a permanent joint between them. The thickness of the solder layer is advantageously less than approximately 5 .mu.m. The wetting layer is preferably the intermetallic compound Ni.sub.3 Sn.sub.4, and the auxiliary layer is formed by codepositing the metallic components of this intermetallic together with the barrier metal.

Permanent metallic bonding method

A device such as a laser is bonded to a submount such as diamond by a process in which the submount is successively coated with an adhesion layer such as titanium, a barrier layer such as nickel, and a gold-tin solder-metallization composite layer formed by sequential deposition on the barrier layer a number (preferably greater than seven) of multiple alternating layers of gold and tin, the last layer being gold having a thickness that is equal to approximately one-half or less than the thickness of the (next-to-last) tin layer that it contacts immediately beneath it. The bonding is performed under applied heat that is sufficient to melt the solder-metallization composite layer. Prior to the bonding, (in addition to the submount) the device advantageously is coated with gold and optionally with a similar gold-tin solder-metallization composite layer, at least at locations where it comes in contact with the gold-tin solder-metallization composite layer.

Bonding method using solder composed of multiple alternating gold and

Alignment of each of a plurality of depending first conductive members (16), in an array of orthogonal rows and columns on an article (12), with a corresponding second conductive member (18) arranged in a like array on a substrate (14), is accomplished by positioning the article in spaced relationship from the substrate. The arrays of first and second conductive members (16,18) are first angularly aligned by rotating the article (12) so that the offset between a first column of first and second conductive members on the article and substrate, respectively, as seen by a television camera (32) at a first end of the article and substrate is the same as the offset between a second column of first and second members on the article and substrate, respectively, at the other end thereof as seen by a second camera (30). Translational alignment of the arrays of first and second conductive members (16,18) is accomplished by displacing the substrate (14) so that the first and second conductive members in the first column on the article and substrate, respectively, are aligned at the same time that the first and second conductive members in the first row of first and second conductive members on the article and substrate, respectively, are aligned.

Article alignment method and apparatus

Article alignment method

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Wescosville, PA, United States of America

Yiu-Man Wong