Browse Prior Art Database

Stud Structure of Carrier for Flip-Chip Attachment Packaging

IP.com Disclosure Number: IPCOM000112132D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Maeda, Y: AUTHOR [+2]

Abstract

Disclosed is a carrier terminal structure for direct chip attachment using Flip-Chip Attachment (FCA) technology. This structure enables to make reliable flip-chip joints for fine pitched semicinductor terminal pads.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 78% of the total text.

Stud Structure of Carrier for Flip-Chip Attachment Packaging

      Disclosed is a carrier terminal structure for direct chip
attachment using Flip-Chip Attachment (FCA) technology.  This
structure enables to make reliable flip-chip joints for fine pitched
semicinductor terminal pads.

      Fine pitch I/O joints between a semiconductor chip and a chip
carrier have to solve the following obstacles at flip-chip joints.

o   It becomes difficult to keep a desired distance between the chip
    and the carrier to absorb CTE (coefficient of thermal expansion)
    mismatch therebetween because the size of bumps built on the chip
    has to be very small due to the fine pitch,.

o   Some methods to fabricate bumps on a chip were reported but they
    require expensive processes.

      The disclosed structure solves the obstacles by forming fine
studs on the carrier utilizing currently available panel
manufacturing process.

      As shown in Fig. 1, metal bumps, such as gold, which are
wettable to solder are formed on Al terminals of the semiconductor
chip.

      As shown in Fig. 2, fine and tall Cu studs are formed on the
chip carrier substrate in a pattern corresponding to the chip bumps
with use of pattern palting method.  The studs are connected to
signal or power lines in the carrier at the bottom of the studs.

      A required volume of solder is applied on the chip bumps (Fig.
3) or the carrier studs.  The chip is placed on the car...