SEM sample preparation method

Abstract

The invention provides a method for preparing SEM samples, which at least includes the following steps: S1: providing a sample to be tested; S2: removing the metal layer, and placing the sample to be tested after removing the metal layer into a scanning electron microscope ; S3: Use a scanning electron microscope electron beam to scan the preset area of ​​the sample to be tested after removing the metal layer, so that the area is carbonized; S4: Soak the structure obtained in step S3 in hydrogen peroxide to remove the metal S5: Soak the structure obtained in step S4 in a hydrofluoric acid solution to remove part of the interlayer dielectric layer; S6: Rinse the structure obtained in step S5 with water so that the word lines, control gates and erase gates are The water washes away. The present invention removes unnecessary structures around the floating gate and enhances the contrast of SEM images; in the preparation process of samples, SEM electron beam scanning and chemical processing are mainly used, which improves the hit rate of the target and can ensure the integrity of the target and the efficiency of sample preparation. high.

Description

technical field [0001] The invention belongs to the field of semiconductor manufacturing, and relates to a method for manufacturing an observation sample, in particular to a method for preparing an SEM sample. Background technique [0002] Integrated Circuits (Integrated Circuit, IC) follow the evolution of Moore's Law, the integration level is continuously improved, and the feature size is continuously reduced. In the ever-shrinking device structure, the defects that cause device failure are getting smaller and smaller. Although various defects in most manufacturing processes can be caught by defect detection systems, it is impossible to tell the producer why these defects occur. Scanning Electron Microscope (SEM) is the most commonly used failure analysis equipment. SEM can be used to observe the sample cross section or surface in a subtle way. The magnification of SEM can range from thousands of times to hundreds of thousands of times, and the resolution can reach 3nm, ...

AI Technical Summary

Problems solved by technology

[0009] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method for preparing SEM samples, which is used to solve the problems that the samples prepared in the prior art have low contrast, are easy to miss the target, and are difficult to ensure the integrity of the target

Images