Method for preparing test sample by 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 pretreated sample with a target layer having opposite first and second surfaces; The pretreated sample is fixed on the sample stage; along the direction towards the first surface and / or the second surface of the target layer, the ion beam is used to perform the first thinning of the pretreated sample, and the thickness of the pretreated sample is reduced. Thinning to a preset thickness; forming several through holes through the pretreated sample; continuing to perform a second thinning on the pretreated sample formed with the through holes until the target layer is thinned to a target thickness. The above method can avoid deformation of the target layer during the thinning process.

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...

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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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