Alkaline polishing solution for inhibiting galvanic corrosion of copper-ruthenium barrier layer and preparation method thereof

Abstract

The invention relates to alkaline polishing liquid for inhibiting galvanic corrosion of a copper-ruthenium barrier layer and a preparation method of the alkaline polishing liquid. The polishing liquid is prepared from the following components in percentage by weight: 0.3 percent of H2O2, 0.5 percent to 5 percent of beta-hydroxyethylenediamine, 0.1 percent to 0.3 percent of ethylenediaminetetraacetic acid-tetra-tetrahydroxyethylethylenediamine, 0.1 percent to 5 percent of an FA / O type surfactant, 0.8 percent to 1.5 percent of a pH inorganic acid regulator and the balance being de-ionized water; the pH value of the alkaline polishing liquid is 9 to 10; the alkaline polishing liquid is obtained through a mixing manner and an inhibitor does not need to be added; the alkaline polishing liquid is easy to wash and the potential difference between Ru and Cu is effectively overcome; the current density of the galvanic corrosion is reduced and a serious galvanic corrosion problem between the Ru and the Cu is solved; the galvanic corrosion between the Ru and the Cu is inhibited very well.

Description

Technical field [0001] The invention relates to a polishing liquid applied in the field of microelectronics and a preparation method thereof, in particular to an alkaline polishing liquid for inhibiting galvanic corrosion of a copper ruthenium barrier layer and a preparation method thereof. Background technique [0002] With the continuous development of IC technology, integrated circuits are developing in the direction of high performance and high integration. At this stage, they have reached the level of very large scale integration (GLSI). Currently, chemical mechanical planarization (CMP) technology is the most widely used global planarization technology, and the traditional interconnection diffusion barrier layer Ta / TaN is still used. It has good barrier properties and thermal stability. However, with the development of the integrated circuit industry and the reduction of feature size, in order to reduce the resistance of the interconnection line and improve the reliability...

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Problems solved by technology

[0004] In 2011, B.C.Peethala reported the use of ascorbic acid (C 6 h 8 o 6 ) and benzotriazole (BTA) are used as inhibitors in potassium periodate-based polishing fluids, which improve the galvanic corrosion of Ru and Cu, but also reduce the rate of Cu and Ru

In 2014, the literature also reported that the inhibitor ascorbic acid (C 6 h 8 o 6 ) and benzotriazole (BTA) on the corrosion of Cu and Ru, the conclusion is similar to the study of B.C.Peethala, they proposed the galvanic corrosion between Cu and Ru in the polishing solution containing ascorbic acid and benzotriazole It can be suppressed, but it is far from achieving the desired effect, and the addition of inhibitors such as BTA is not conducive to the cleaning of the wafer

And galvanic corrosion also directly affects the quality rate, yield and reliability of the chip

Therefore, the galvanic corrosion between Ru and Cu has become a technical problem that must be overcome in the development of microelectronics technology but has not been well solved.

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