Surface cleaning method for Ti barrier layer material subjected to chemically mechanical polishing

Abstract

The invention discloses a surface cleaning method for a Ti barrier layer material subjected to chemically mechanical polishing and aims to provide a method which can reduce the subsequent processing cost of alkaline chemically mechanical polishing of the Ti barrier layer material, is easy to use, is practicable and can improve the surface quality of a Ti barrier layer. The method comprises the following steps of: preparing water-soluble surface cleaning solution, namely adding a surfactant and an FA / O II type chelating agent into ultrapure water with the resistance of more than 18 megohms under stirring; uniformly stirring to obtain the water-soluble surface cleaning solution with the pH value of between 6.5 and 7.5; polishing and cleaning the Ti barrier layer material by using the cleaning solution at the high flow speed of between 1,000 and 5,000 ml / min under the low pressure of between 0 and 0.01 atmosphere; polishing and cleaning the Ti barrier layer material by using diluted rustinhibitor solution quickly at the flow speed of between 1,000 and 5,000 ml / min under zero pressure; and washing the Ti barrier layer material by using the ultrapure water with the resistance of more than 18 megohms under zero pressure at the flow speed of between 1,000 and 5,000 ml / min.

Description

technical field [0001] The invention relates to a method for cleaning the surface of a Ti barrier layer material after chemical mechanical polishing. Background technique [0002] Pure titanium is a silver-white metal with many excellent properties. The density of titanium is 4.54g / cm3, which is 43% lighter than steel and slightly heavier than the prestigious light metal magnesium. The mechanical strength is about the same as that of steel, twice that of aluminum and five times that of magnesium. Titanium is resistant to high temperatures, with a melting point of 1942K, which is nearly 1000K higher than gold and nearly 500K higher than steel. Titanium is a chemically active metal. When heated, it can interact with non-metals such as O2, N2, H2, S and halogens. However, at normal temperature, an extremely thin and dense oxide protective film is easy to form on the surface of titanium, which can resist the action of strong acid or even aqua regia, showing strong corrosion ...

AI Technical Summary

Problems solved by technology

At present, the method of cleaning the surface of the Ti barrier layer after batch polishing and production uses water washing. Due to the high temperature, high energy, and high surface tension of the wafer surface, although the polishing stops, the reaction on the wafer surface has a lagging process, and simple water washing cannot Avoid uneven distribution of polishing liquid, contamination of metal ions, etc., so that there is an erosion ring on the surface of the Ti barrier material after cleaning. On an 8-inch chip, there are more than 1,000 particles with a particle size greater than 0.1 micron, which causes subsequent processing. Increase in cost and decrease in device yield

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