Chemical mechanical polishing solution

Abstract

The invention discloses chemical mechanical polishing solution, which comprises an exciting agent, a strong oxidant precursor, an abrasive and water. The chemical mechanical polishing solution can obviously improve the polishing speed of tungsten.

Description

technical field [0001] The invention relates to a chemical mechanical polishing liquid, in particular to a chemical mechanical polishing liquid containing an activator and a strong oxidizing agent precursor. The present invention further relates to using the chemical mechanical polishing liquid described in the present invention in tungsten chemical mechanical polishing. Background technique [0002] With the continuous development of semiconductor technology and the continuous increase of interconnection layers in large-scale integrated circuits, the planarization technology of conductive layers and insulating dielectric layers has become particularly critical. In the 1980s, the chemical mechanical polishing (CMP) technology pioneered by IBM is considered to be the most effective method for global planarization. [0003] Chemical Mechanical Polishing (CMP) consists of chemical action, mechanical action, and a combination of both. It usually consists of a grinding table wi...

AI Technical Summary

Problems solved by technology

However, due to the introduction of organic acids, the pH of the polishing solution is low (usually lower than about 2.7), causing equipment corrosion

In addition, the polishing liquid containing ferric nitrate has a narrow pH adjustment range

Because when the pH value is higher than 2.7, ferric nitrate will be hydrolyzed to form ferric hydroxide precipitate, which will cause the polishing fluid to fail and limit its pH adjustment ability

In terms of environmental protection, due to the addition of organic acids, the organic content (COD) in the polishing waste liquid is increased, which is not conducive to environmental protection

In addition, the stability problem of oxidant hydrogen peroxide still exists

Although organic acid is added as a stabilizer to improve the decomposition rate of hydrogen peroxide, its decomposition rate is still high. Usually, the concentration of hydrogen peroxide will decrease by more than 10% within two weeks, resulting in a decrease in polishing speed and gradual decomposition of the polishing solution.

[0013] Chinese patent CN1966594A discloses a method of adding an etch inhibitor to the above catalytic system, but since the catalyst used is still iron, problems such as easy decomposition of hydrogen peroxide and poor stability still exist

[0018] Among the above-mentioned 3 patents, the combination of silver and hydrogen peroxide (for example, hydrogen peroxide plus silver nitrate) does not have the effect of significantly increasing the polishing speed of tungsten, and only the combination of iron and hydrogen peroxide can significantly improve the polishing speed of tungsten, (the above three The examples of the patent itself demonstrate both of these points)

Images