Fiducial for aligning an integrated circuit die

Details Fiducial for aligning an integrated circuit die Fiducial for aligning an integrated circuit die

1996-12-20

1999-08-24

Martin-Wallace, Valencia

Active solid-state devices (e.g., transistors, solid-state diode

Alignment marks

257 48, 257798, H01L 23544

Patent

active

059428058

ABSTRACT:
A fiducial for aligning an integrated circuit die. In one embodiment, the fiducial is configured to be exposed by laser chemical etching through a silicon substrate through the back side of a C4 packaged integrated circuit die. The presently described fiducial includes floating diffusion regions disposed in the substrate. An oxide layer free of metal contacts is disposed over the diffusion regions within the fiducial region of the integrated circuit. A metal pattern layer is disposed beneath the oxide layer to provide alignment information. The metal pattern layer is configured to be visible through the oxide layer after the silicon substrate has been removed from the fiducial region. A light block is disposed between the metal pattern layer and an underlying epoxy underfill layer to minimize the risk of an excessive amount of light from being exposed to the underlying epoxy layer, which minimizes the risk of the epoxy layer from damaging the integrated circuit from excessive light exposure. Since the presently described fiducial does not include any contacts in the oxide layer, the additional step of utilizing a focus ion beam mill is no longer necessary and the presently described fiducial therefore only needs to be etched with a laser chemical etcher to be exposed.

REFERENCES:
patent: 4479830 (1984-10-01), Koshino et al.
patent: 5241454 (1993-08-01), Ameen et al.
patent: 5304839 (1994-04-01), Chen et al.
patent: 5365103 (1994-11-01), Brown et al.
patent: 5612573 (1997-03-01), Lewis et al.
"Shield for Protecting an Integrated Circuit During Etch of Silicon Substrate," IBM Technical Disclosure Bulletin, vol. 38 (2), 1995.

Affiliated with

Also associated with

Rating

Fiducial for aligning an integrated circuit die does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fiducial for aligning an integrated circuit die, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fiducial for aligning an integrated circuit die will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-469314