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Combined E-Beam and Ion Beam for Circuit Edits

IP.com Disclosure Number: IPCOM000030140D
Publication Date: 2004-Jul-29
Document File: 4 page(s) / 88K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that consists of an electron beam (E-beam) and back scatter electron detector, in addition to the standard ion beam which performs the milling. The electron image "sees" the circuit below the silicon surface by imaging to depths which are not "seen" by the focused ion beam (FIB) image.

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Combined E-Beam and Ion Beam for Circuit Edits

Disclosed is a method that consists of an electron beam (E-beam) and back scatter electron detector, in addition to the standard ion beam which performs the milling. The electron image “sees” the circuit below the silicon surface by imaging to depths which are not “seen” by the focused ion beam (FIB) image.

Background

Circuit editing (CE) on flip-chip products are performed by the FIB. Two major problems that must be overcome in order to perform successful flip-chip CE are:

§         Navigation of the ion beam to the desired point of modification in the circuit

§         Accuracy of the beam placement on the unit

Various techniques and special components have been introduced into FIB systems in order to improve the accuracy of the ion beam and/or stage placement. Typical components are: the IR camera (for imaging the active elements of the electronic circuit through the bulk Silicon) and a laser interferometer (for stage movement control and accuracy). The IR camera is for rough alignment only, as a preliminary step before exposing special diffusion patterns for locking points; this is because the accuracy is limited due to a IR wavelength of about 1um. Stage move accuracy in the present state of the art tools is approximately 0.2 um.

General Description

In the disclosed method, the electron image “sees” the circuit below the silicon surface by imaging to depths which are not “seen” by the FIB image. This capability provides an image of the underlying circuitry, and allows the subsequent placement of the FIB milling box directly over a buried line. The matching of the electron and ion images is necessary, and can be done in various options that differ in levels of interactivity.

The highest level of interactivity is matched electron and ion images, in which the images are overlaid. The FIB milling box is drawn based on an electron overlaid image. For this level, a pre-registration between the electron and ion beams is necessary.

A second level of int...