Method for preparing test sample using FIB and test sample

Abstract

The present invention relates to a method for preparing a test sample using FIB and a test sample, the method comprising: providing a pre-treated sample having a target layer, the target layer havinga first surface and a second surface opposite to each other; fixing the pretreated sample on a sample table; carrying out first thinning on the pretreated sample by adopting an ion beam along the direction towards the first surface and/or the second surface of the target layer, and thinning the pretreated sample to a preset thickness; forming a plurality of through holes penetrating through the pretreated sample; and continuously carrying out second thinning on the pretreated sample with the through hole until the target layer is thinned to a target thickness. According to the method, deformation of the target layer in the thinning process can be avoided.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing test samples by using FIB. Background technique [0002] The use of focused ion beam (FIB) has become an important method for special sample preparation and fine structure processing because of its high precision and fast sample preparation. It is widely used in the preparation of TEM (projection electron microscope), SEM (scanning electron microscope) and EBSD ( Electron backscattered diffraction electron microscope) test samples. [0003] During the adjustment process of the chip process, it is often necessary to study the growth conditions, microstructure, inter-film bonding force and other properties of each film layer, so as to provide data reference and support for the preparation of structural samples. [0004] When preparing samples by FIB, some film layers to be tested will be deformed due to internal stress after being thinned due to the d...

AI Technical Summary

Problems solved by technology

[0004] When preparing samples by FIB, some film layers to be tested will be deformed due to internal stress after being thinned due to the deposition process, material properties, etc., and accurate measurement cannot be performed accurately

[0005] For example, when it is necessary to perform EBSD test on the target material layer, the sample of the target material layer prepared by FIB will be deformed, which will seriously affect the Bragg diffraction of the crystal plane and the generation of Kikuchi patterns, thereby affecting the accuracy of the test results

Further, for the EBSD test, the effective area of ​​the sample needs to be larger, such as greater than 9um 2 , while using the existing FIB preparation technology, the larger the effective area of ​​the sample, the easier it is to deform, so it is difficult to obtain an EBSD test sample that meets the requirements

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