The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 2001
Filed:
Sep. 03, 1999
Kuang-Ho Liao, Taipei, TW;
Vanguard International Semiconductor Corporation, Hsin-Chu, TW;
Abstract
A new method and apparatus is provided for obtaining a quantitative reading of the strength of the chip bonding connections and for testing the quality of the bonding that is established between a chip and the chip pad or tapes on which the chip is mounted. The invention makes use of the fact that the lead frame, that is the frame that contains the leads to which the chip is connected, uses a material for the metal interconnects that can be controlled by a magnetic field. A metal alloy is commonly used to fabricate the interconnect leads on the lead frame. The alloy is typically selected based on considerations of thermal stress (between the chip and the chip pad or tapes or equivalent interface on which the chip is mounted) and on considerations of delamination between the lead frame and the encapsulating compound. Ni—Fe is an alloy that is frequently used as the material for the metal interconnects on the lead frame. A magnetic field is applied such that this magnetic field holds the lead frame firmly in place with respect to the fixture plate. The lead frame/die combination is mounted such that the chip faces upwards. The die-shear test can now be performed.