Preparation method of tem sample of nickel metal silicide

Abstract

The invention discloses a method for preparing a TEM sample of a nickel metal silicide, comprising steps: step 1, providing a chip, and the nickel metal silicide is formed in a selected area of ​​the device layer of the chip and the interface of a semiconductor substrate; step 2 1. Form a metal protective layer to completely cover the area of ​​the target position that needs to be analyzed by TEM; step 3, use ion beam to cut the TEM sample for TEM analysis; step 4, tilt the chip at a certain angle, and use ion beam to TEM The semiconductor substrate layer of the sample is subjected to ion bombardment and the semiconductor substrate layer is completely amorphized. The invention can improve the TEM contrast imaging difference between the semiconductor substrate layer and the nickel metal silicide of the TEM sample. The TEM sample that can directly perform clear imaging of the nickel metal silicide in the TEM mode can be obtained, thereby shortening the TEM observation time of the sample and reducing the observation cost.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for preparing a transmission electron microscope (TEM) sample of a nickel metal silicide. Background technique [0002] TEM is a very important analytical tool in material science research. It can analyze the shape, structure and composition of samples. It has a very wide and increasingly important application in the field of integrated circuit analysis. Focused ion beam (FIB) Sample preparation is the most important TEM sample preparation method in the semiconductor field. [0003] With the improvement of chip technology nodes, nickel silicide alloys, that is, nickel metal silicides, are used in integrated circuit manufacturing processes, and chip failures caused by structural defects in nickel silicide (NiSi) are also increasing. The conventional method of preparing TEM samples by FIB, in order to avoid sample distortion, the sample will...

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Problems solved by technology

Depend on figure 1 As can be seen from the TEM photographs, it can only be seen that the nickel metal silicide is located within the area of ​​the dotted circle 104, but the nickel metal silicide cannot be distinguished from the silicon substrate 101, so it is impossible to realize the detection of the nickel metal silicide. Analysis of structural defects

[0004] Existing methods can only analyze NiSi morphology by scanning transmission electron microscope (STEM) high-angle annular dark field detector (HAADF) imaging, but it will greatly increase the cost of TEM observation and reduce the use efficiency of the machine

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