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Browse Prior Art Database

Interposer for Direct Chip Attach or Surface Mount Array Devices

IP.com Disclosure Number: IPCOM000105279D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

Imken, RL: AUTHOR [+2]

Abstract

Disclosed is a device and manufacturing process providing a means of temporarily attaching direct chip attach (DCA) or surface mount array (SMA) electronic components. The device serves as an interposer between a circuit carrier and the electronic component.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Interposer for Direct Chip Attach or Surface Mount Array Devices

      Disclosed is a device and manufacturing process providing a
means of temporarily attaching direct chip attach (DCA) or surface
mount array (SMA) electronic components.  The device serves as an
interposer between a circuit carrier and the electronic component.

      The basic construction of the interposer is shown in Fig. 1.  A
traditional ceramic package is modified such that C4 solder balls or
SMA solder balls are applied to the side which will contact the
circuit carrier (Fig. 4).  The top surface of the ceramic package is
plated with palladium dendrites (Fig. 5) and as disclosed in[*].

      In the final application, the interposer is attached
permanently to a circuit carrier by the C4 or SMA solder joints (Fig.
2).  The inter- poser is then free to serve as a socket for a device
with the same footprint.  The nature of the dendrite interface makes
it especially appealing as a temporary attachment means since
components can be placed on the dendritic contacts, tested and
removed without significant damage to C4 or SMA solder balls.  The
ceramic carrier requires no internal wiring, only vertical conductor
vias which serve to replicate the circuit carrier pad footprint on
the dendritic surface.

      Fig. 3 shows an extension of the original concept wherein the
ceramic carrier is supplemented by an alignment aid.  A secondary
wall is formed around the carrier, extending above t...