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Magnetic Rollers with Substrate Thickness Detection Capability for Die Attach

IP.com Disclosure Number: IPCOM000177031D
Publication Date: 2008-Dec-03
Document File: 3 page(s) / 635K

Publishing Venue

The IP.com Prior Art Database

Abstract

High volume manufacturing in BGA clean rooms often deals with multiple conversions in machines to fit different package sizes. This also applies for the Die Attach process which sees 30mm, 40mm and MAPBGA packages being run on the same machine through out the day. As such, the conversion required also consists of making adjustments on the substrate rollers which play an important role in indexing the substrate, and ensuring that placement accuracy is well within the 2 mil or 50 um limit. Due to the design of the rollers, there is much manual handling in tightening and positioning the rollers on the substrate. Some of the problems that have cropped up in the past include die attach epoxy on wire bond lead (due to poor roller tightening), substrate mask crack (excessive force from the rollers) and gradual wear and tear of the roller screws. This defensive publication describes a solution that uses magnetic rollers that can be latched on to the substrate indexer bar for various substrate widths. No tightening, adjustments etc, are required. The usage of substrate thickness detection (Z-height sensor) is also discussed in this work. This solution can be applied in epoxy die bonding for leaded packages as well. Keywords: Die attach, Magnetic rollers, Substrate thickness

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Magnetic Rollers with Substrate Thickness Detection Capability for Die Attach

Abstract

High volume manufacturing in BGA clean rooms often deals with multiple conversions in machines to fit different package sizes. This also applies for the Die Attach process which sees 30mm, 40mm and MAPBGA packages being run on the same machine through out the day. As such, the conversion required also consists of making adjustments on the substrate rollers which play an important role in indexing the substrate, and ensuring that placement accuracy is well within the 2 mil or 50 um limit. Due to the design of the rollers, there is much manual handling in tightening and positioning the rollers on the substrate. Some of the problems that have cropped up in the past include die attach epoxy on wire bond lead (due to poor roller tightening), substrate mask crack (excessive force from the rollers) and gradual wear and tear of the roller screws.

This defensive publication describes a solution that uses magnetic rollers that can be latched on to the substrate indexer bar for various substrate widths. No tightening, adjustments etc, are required. The usage of substrate thickness detection (Z-height sensor) is also discussed in this work. This solution can be applied in epoxy die bonding for leaded packages as well.

Keywords: Die attach, Magnetic rollers, Substrate thickness

1.  Problem Description

In the current production environment at BGA Assembly in KLM, the die attach process runs different types of substrates. The Die Bonder’s “substrate roller”, which is an integral part of the die bonder to hold down the substrates, requires...