Wafer cleaning device and cleaning method

Abstract

The invention discloses a wafer cleaning device and a cleaning method and relates to the cleaning technical field of a semiconductor integrated circuit device. The wafer cleaning device comprises a wafer bearing unit for bearing a wafer, a wafer front surface ultrasonic cleaning nozzle arranged above the wafer bearing unit, a wafer back surface ultrasonic cleaning unit arranged in the wafer bearing unit, a rotary shaft, a hollow pipe, a spraying arm, a spraying arm motor and a wafer rotating motor. According to the invention, a uniform sound field is formed in cleaning fluid of the upper surface and the lower surface of the wafer through phase shift and distortion formed by the synthesis of ultrasonic wave with a first preset frequency, generated by the wafer front surface ultrasonic cleaning nozzle and ultrasonic wave with a second preset frequency, generated by the wafer back surface ultrasonic cleaning unit, so that the wafer is cleaned, the strength uniformity of the ultrasonic wave sound field on the wafer is met, the cleaning effect on the wafer is improved, meanwhile, the damage to the feature size and structure of the wafer caused by severe cavitation generated by the ultrasonic wave is reduced and eliminated.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuit device cleaning, in particular to a wafer cleaning device and a cleaning method. Background technique [0002] As the feature size of integrated circuits enters the deep sub-micron stage, the requirements for cleaning control in the wafer manufacturing process are getting higher and higher, and the uniformity of cleaning has become a challenging issue. Cleaning under the action of megasonic waves helps to improve the cleaning effect of the wafer, and can greatly improve the removal efficiency of polluting particles. However, due to the interference phenomenon of the megasonic sound field, many hot spots with high sound field intensity will be formed on the wafer surface, and many dead spots with low sound field intensity will be formed at the same time, so the uniformity of the sound field intensity on the wafer surface is difficult to achieve. In addition, the hot spots ...

AI Technical Summary

Problems solved by technology

However, due to the interference phenomenon of the megasonic sound field, many hot spots with high sound field intensity will be formed on the wafer surface, and many dead spots with low sound field intensity will be formed at the same time, and the uniformity of the sound field intensity on the wafer surface is difficult to achieve.

In addition, the hot spots formed by the megasonic sound field interference can easily cause the bubbles to burst, and the cavitation formed by the bubble bursts also increases the risk and possibility of damage to the microstructure of the graphics wafer

[0003] Although in the process of improvement, there is a method of using frequency scanning to reduce the formation of hot spots, but since the frequency scanning only surrounds this central frequency, and this scanning around the center frequency is only applied to one megasonic oscillator, the megasonic oscillator The natural frequency of the mechanical vibration is fixed (generally equal to the center frequency of the megasonic wave), and the change of the deviation from the center frequency will cause the amplitude of the vibrator to decrease and the energy of the transmitted megasonic wave to decrease, so that the acoustic energy density formed on the surface of the wafer increases with the Scanning frequency changes, unable to produce a uniform sound field

Although the method of frequency superposition and combination is also useful, since the voltage of frequency superposition combination is still applied to the same megasonic vibrator, the vibration of the vibrator is too large to affect the efficiency of electroacoustic conversion, which reduces the cleaning effect.

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