Method and system for exposing delicate structures of a device encapsulated in a mold compound

Abstract

A system utilizes a laser to remove the mold compound of an IC without damaging the internal die, wire leads, solder connections and any other critical structures encapsulated within the mold compound, thereby leaving them available for the provisional and electrical analysis. A laser beam is focused through appropriate optics onto a plane corresponding to the surface of an IC. A layer of material which is opaque at the wave length of the laser beam is applied at the surface of the IC chip to be ablated prior to each pass of the laser. A spray nozzle may be provided to move in synchronous motion ahead of the laser being to apply coat of the opaque material.

Description

[0001] Cross References to Related Applications [0002] This application claims priority under 35 U.S.C.111(a) to U.S. Utility Patent Application No. 12 / 580,652, filed October 16, 2009, entitled "METHOD AND SYSTEM FOR EXPOSING DELICATE STRUCTURES OF ADEVICE ENCAPSULATED IN AMOLD COMPOUNT" Interest, the disclosure of this application is incorporated herein by reference in its entirety. Background technique [0003] The present invention relates to methods and systems for utilizing ablative lasers for failure analysis in the manufacture of integrated circuits, and in particular to the manufacture of electrical devices or devices having components encapsulated in mold compounds containing glass or silicon impurities Circuits, methods and systems. [0004] The integrated circuit has failed. However, once an integrated circuit fails, it is often necessary to determine what caused the failure, which may trigger a product recall for corrective action. When analyzing a failure, ea...

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Problems solved by technology

However, if figure 2 It can be seen that the glass 20 inside the composite 24 of the IC 14 disperses the laser energy so that the energy is not concentrated which reduces the energy density to a point below the point where it is sufficient to ablate the composite

Raising the laser beam power to a level high enough to overcome the energy loss due to dispersion can result in the destruction of sensitive IC components at locations where the laser beam is not dispersed, destroying or damaging the IC chip to the point where failure analysis cannot be performed

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