Browse Prior Art Database

Method of Flip-Chip Alignment

IP.com Disclosure Number: IPCOM000102541D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+4]

Abstract

Joining of semiconductor chips to substrates face down or "Flip-Chip" has become a standard technique in the integrated circuit component industry. The techniques require esoteric materials, infrared aligners, precision dicing/sawing of chips, and patterned fiducials on the carrier modules. Disclosed is a technique that avoids many of the cumbersome problems associated with this technology.

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This is the abbreviated version, containing approximately 83% of the total text.

Method of Flip-Chip Alignment

       Joining of semiconductor chips to substrates face down or
"Flip-Chip" has become a standard technique in the integrated circuit
component industry.  The techniques require esoteric materials,
infrared aligners, precision dicing/sawing of chips, and patterned
fiducials on the carrier modules.  Disclosed is a technique that
avoids many of the cumbersome problems associated with this
technology.

      Novel to the Flip-Chip alignment method disclosed is the
utilization of an optical fiber that has been metallized and serves
as a cylindrical mirror.  Depicted in the figure is a schematic of
the alignment process.  The delineated and patterned chip 1 and
carrier 2 contain metal bonding pads, with the pattern on the
carrier, the mirror image of the pattern on the chip. The chip is
held on a stage by vacuum, which is connected to a mechanical arm 3
that pivots. The carrier (substrate) is also held by vacuum and is
mounted on a stage that allows X, Y, Z, and Theta translation.  A
quartz fiber 4 a few microns in diameter, coated with a highly
reflective metal such as silver, aluminum or gold, is placed across
the carrier. The arm containing the chip is lowered to a position
just above the cylindrical mirror, and over the carrier, which is
illuminated.  A low-power optical microscope allows viewing of both
the chip and the carrier in a reflection from the metallized fiber.

      Micro-positioning of the carrier is achieved by...