Method for forming dynamic grating stripes

Abstract

A forming method for dynamic grating fringe provides base materials with polishing surface located with multiple reflection areas. Then it is to provide a laser and to let laser shoot on the reflection areas of base materials and forms a grating fringe after intervention.

Description

technical field [0001] The present invention relates to a method for forming a dynamic grating pattern (laser induced grating pattern), and in particular to a method for incident optical interference strain gauge (Interference Strain / Displacement Gage, ISDG) by pulse laser (pulse laser) A method to generate dynamic grating stripes. Background technique [0002] With the continuous progress of the semiconductor industry, integrated circuits are constantly moving towards the direction of miniaturization and high operating efficiency. In order to meet the needs of miniaturization and high operating efficiency at the same time, the integration of integrated circuits must become more critical. . Since the functions of integrated circuits are increasingly diversified, the design also tends to be a multi-layer design. In the manufacturing process of integrated circuits, processes such as deposition, lithography, etching, and chemical mechanical polishing (CMP) are often used. Bas...

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Problems solved by technology

Therefore, the known technology cannot provide a narrower frequency surface ultrasonic signal, and the signal / noise ratio (S / N) is low, which leads to poor resolution of the thickness measurement of the film to be measured

[0009] (2) It is extremely difficult to adjust the incident angles of the two pulsed lasers to be consistent, so it is known that due to the inconsistent incident angles, it is often difficult to accurately determine the distance between bright and dark grating stripes or the wavelength of the surface ultrasonic waves, or even produce grating stripes. And other problems, which lead to the inaccurate measurement of the thickness of the film to be measured

[0010] (3) The known method of two pulsed lasers is used to measure the thickness of metal thin films, but it is usually limited to thin films with a thickness greater than several thousand angstroms (angstrom, ), so thinner films cannot be measured.

[0011] (4) In general on-line production machines, it is known that it is not practical to use two pulsed lasers for on-line measurement. The reason is that the two pulsed lasers must be installed in the production machine at the same time. Difficulty on

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