Method for positioning low impedance tiny flaws in comb metal wire structure

Abstract

The invention discloses a method for positioning low impedance tiny flaws in a comb metal wire structure, comprising the following steps: step one, punching a hole to an earthed terminal by a focused ion beam electron microscope (EMS), and realizing one end of a comb meal wire to be earthed by adopting a focused ion beam electron microscope metallic coating; step two, dividing the comb metal wire into n equal parts, wherein primary voltage contrast detection is performed at each time of dividing, the flaws can be positioned within the halved original area by each voltage contrast, and the flaws can be positioned within the area range of one [n(th) powder]th after evenly dividing for n times, and n is a positive integer; and step three, in the positioned tiny area, adopting an electron microscope for high accelerating voltage scanning to obverse the flaws buried by an insulating film. The method in the invention has high positioning speed and high efficiency, can solve the problem that flaws of some metal growth etching related technologies in semiconductor production lines can not be found out, and can greatly save manpower and use time of the electron microscope for scanning.

Description

technical field [0001] The invention relates to a failure analysis and positioning technology for semiconductor chips, in particular to a positioning method for low-impedance tiny defects in a comb-shaped metal wire structure. Background technique [0002] At present, the methods for locating tiny defects in comb-shaped metal wire structures can be roughly divided into the following categories: [0003] 1. Observation with an optical microscope. The disadvantage is that due to the limitation of resolution greater than 1 micron, defects smaller than 1 micron cannot be observed. [0004] 2. Use a scanning electron microscope to magnify and observe, and the resolution can reach several nanometers. Its defect is: but because generally at least thousands of comb-shaped metal wires are interlaced together, and the area is often more than 100 microns by 100 microns, it takes a long time to find defects smaller than 1 micron. [0005] 3. Photo-induced impedance change technology,...

AI Technical Summary

Problems solved by technology

[0008] The beneficial effect of the present invention is that it provides a method for accurately locating fine defects in comb-shaped aluminum wires, which has fast positioning speed and high efficiency, and on the one hand, it solves the problem that some metal growth and etching related processes in the semiconductor production line cannot be found. On the other hand, it can save a lot of manpower and the time of using the scanning electron microscope

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