Preparation method of transmission electron microscopic sample

Abstract

The invention provides a preparation method of a transmission electron microscopic sample. The method comprises the following steps: providing a sample with length, width and thickness, wherein the sample has an observation target, and the observation target includes at least one elongation structure along a thickness direction or a multilayer stack structure; marking the surface of the sample defined in the length and width directions, wherein a distance from the marked position to the observation target is in a preset distance ring; grinding the sample along a direction vertical to the thickness direction to the marked position; arranging the sample on a supporting desk, and allowing the grinding surface of the sample to depart from the supporting desk and the opposite surface of the grinding surface to face the supporting desk; forming a conductive film on the back of the sample in order to electrically connect the sample with the supporting desk; and processing the grinding surface by using focused ion beam to obtain the observation sample containing the observation target. The method improves the preparation efficiency, improves the hit rate, and avoids the problem of imaging blurring or image drift induced by charge accumulation in the sample preparation process.

Description

technical field [0001] The invention relates to a semiconductor material analysis technology, in particular to a preparation method of a transmission electron microscope sample. Background technique [0002] With the development of semiconductor technology, the complexity and integration of integrated circuits continue to increase. The number of devices integrated on a single chip has reached hundreds of millions or even billions. Challenges are presented, such as optical microscopy (OM) and scanning electron microscopy (SEM) have not been able to meet the requirements. Due to the high resolution of the Transmission Electron Microscope (TEM, Transmission Electron Microscope) can observe the internal structure of the thin film region, so with the continuous improvement of the semiconductor process level, especially after entering the 130nm process, the Transmission Electron Microscope has become an important tool for observation and analysis. Necessary means for the internal...

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Problems solved by technology

In addition, using such a method, it is easy to cause undercut in the obtained TEM sample 100, as shown in the region 100a

[0008] As above, the TEM sample preparation method of the prior art has many disadvantages, for example, sample damage caused by undercuts is prone to occur during the FIB bombardment process, the true morphology is hidden due to the uneven thickness of the TEM sample, and the blind layer removal operation (blind Delayer) caused by over polishing (over polish), the whole process is a waste of time when preparing larger samples, and it is easy to cause imaging blur or imaging drift in the process of preparing TEM samples, etc.

And when the above problems are encountered, it is often necessary to rework

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