Method for preparing transmission electron microscope sample

Abstract

The invention discloses a method for preparing a transmission electron microscope sample. The method comprises the following steps of: providing a sample with length, width and thickness, wherein at least one elongation structure or multi-layer stack structure along the thickness direction is formed in a region to be observed of the sample; marking the region to be observed of the sample; grinding the sample along a direction which is perpendicular to the elongation direction of the elongation structure or the stacking direction of the stack structure until the mark is exposed; forming a concave pit on the two sides of the region to be observed on a grinding surface respectively; thinning the sample part of the marked region along the concave pit to a specific thickness; and separating and taking the thinned sample part at the region to be observed out. By the method, the preparation efficiency and the observation effect are improved, a protective cover is further assembled on the surface of the sample during the preparation, the sample is prevented from being damaged during the grinding, and the problem that the sample at the region to be observed can easily fall off and bounce out after the preparation is finished is also prevented.

Description

technical field [0001] The invention relates to the field of semiconductor technology and the field of material analysis technology, in particular to a method for preparing a transmission electron microscope sample. Background technique [0002] With the development of semiconductor technology, the complexity and integration of integrated circuits continue to increase, and the number of devices integrated on a single chip has reached hundreds of millions or even billions. To meet the challenges, such as optical microscope (OM) and scanning electron microscope (SEM) can no longer meet the requirements. Due to the high resolution of Transmission Electron Microscope (TEM, Transmission Electron Microscope) can observe the internal structure of the thin film region. Therefore, with the continuous improvement of the semiconductor process level, especially after entering the 130nm process, the Transmission Electron Microscope has become an integrated method for observation and anal...

AI Technical Summary

Problems solved by technology

However, if image 3 As shown, if the failure region 103 also has an extended structure from the bottom surface of the sample to the surface or a multilayer stacked structure ( image 3 Taking the multilayer stack structure as an example, the multilayer stack structure is stacked layers 110, 109, 108, 107, 106 from the surface to the bottom surface respectively), in order to observe a complete extended structure or a multilayer stack structure, the pit 101 and 102 must be greater than or equal to the length of the extension structure or the thickness of the stacked structure. In order to obtain a larger depth, the length and width of the pits 101, 102 also need to be correspondingly larger, making the grinding process time-consuming Longer, that is, the grinding amount of the focused ion beam is positively correlated with the length of the extended structure or the thickness of the stacked structure, which reduces the efficiency of sample preparation

In addition, due to the angle compensation of the focused ion beam in the process of grinding the surfaces 104 and 105, the final shape of the sample in the failure area is finally "wedge", such as image 3 As shown, the thickness of the top is small and the thickness of the bottom is large, and the stacked layers 110, 109 of the sample surface part of the finally obtained region to be observed are relatively thin, which can be clearly imaged under a transmission electron microscope, but the stacked layers 106 at the bottom , 107 are relatively thick, and cannot be clearly imaged under TEM, and their internal structure information cannot be obtained, which affects the observation effect

Images