Method for measuring residual deformation of micro-nano metallic interconnect

Abstract

The invention discloses a method for measuring residual deformation of micro-nano metallic interconnect, belonging to the fields of deformation survey and optical measurement mechanics. The method includes the following steps: fabricating speckles on the surface of the micro-nano metallic interconnect through irradiation by focused ion beams or etching a unidirectional grating through the focused ion beams to be used as the micro-nano mark; then etching a through crack vertical to the axis in the micro-nano mark area through the focused ion beams so as to release the axial residual stress; respectively collecting the micro-nano mark images before and after the crack is etched; calculating the deformation, i.e. the residual deformation of the micro-nano metallic interconnect close to the crack caused by the residual stress by using digital image correlation method. Through the method, micro-nano mark can be fabricated in situ, crack can be etched and images can be collected, and the method has the advantages of in situ measurement, precise positioning, simple operation, non contact, simple data processing, high sensitivity and high measurement precision. Through the method of irradiation by focused ion beams, speckles can be fabricated quickly and the process is simple and convenient.

Description

technical field [0001] The invention relates to a method for measuring the residual deformation of micro-nano metal interconnection wires, belonging to the fields of deformation measurement and optical measurement mechanics. Background technique [0002] Metal interconnects are widely found in semiconductor integrated circuits and micro-electromechanical systems. With the increasing performance requirements for micro-devices, the width of metal interconnects is also getting smaller and smaller, ranging from tens of microns to tens of nanometers. Due to the difference in thermal expansion coefficient between the micro-nano metal interconnection, the substrate, and the insulating layer, the pre-stress that is difficult to eliminate will be generated during the preparation process of the micro-nano metal interconnection, which is called residual stress. This pre-existing residual stress is likely to cause electromigration of the micro-nano metal interconnection during use. If t...

AI Technical Summary

Problems solved by technology

[0003] The commonly used method for evaluating the internal residual stress of metal thin films including thin film wires is X-ray diffraction method. However, the applicable condition of this method is that the spot diameter of X-ray beam is smaller than the lateral and longitudinal dimensions of the object to be measured, while the current spot of X-ray beam can The minimum size achieved is 1 micron, and in actual operation it can usually only reach tens of microns, which is difficult to be suitable for the increasingly thinner micro-nano metal interconnection lines

The substrate curvature measurement method used to measure the residual stress of the film requires the substrate to be in the shape of a disk or a rectangular strip, and the film must cover the substrate, which is difficult to apply to micro-nano metal interconnections

Images