Method for cleaning chip surface after polishing aluminum wire in super large scale integrated circuit

Abstract

The invention relates to a method for cleaning a chip surface after polishing an aluminum wire in a super large scale integrated circuit, which is characterized by comprising the following steps of: preparing a water polishing liquid; weighing deionized water in weight percentage, adding 0.5-5% of surfactant, 0.1-5% of FA / O chelant type II and 0.01-5% of FA / O rust inhibitor type II while uniformly stirring, and preparing into a neutral water polishing liquid after uniform stirring; and after the chemical mechanical polishing (CMP) of the aluminum wire, immediately polishing the workpiece by using the neutral water polishing liquid in a high flow method so as to clean the surface. The invention has the advantage that water polishing is used before a polishing disk stops rotating after CMP, high flow water polishing is used to clean the chip surface, and no corrosion on equipment is produced; non-uniformly distributed polishing liquid and large particles remaining on the chip surface can be washed away quickly, so that a clean and perfect polishing surface can be obtained.

Description

technical field [0001] The invention belongs to the polishing technology, in particular to a method for cleaning the surface of a wafer after the aluminum wiring of a VLSI is polished. Background technique [0002] At present, the most widely used integrated circuits are still products above 90 nanometers, and the wiring metal is aluminum. The chemical mechanical polishing (CMP) process is a very important link in the multilayer wiring process of VLSI. The surface flatness, roughness and surface sticking of ULSI multilayer aluminum wiring after chemical mechanical polishing (CMP) directly affect the The wiring of the next layer of aluminum affects the breakdown characteristics, interface state and minority carrier lifetime of the circuit, which is directly related to the performance quality and yield of IC devices. During the CMP process, a large amount of organic matter, particles, and especially heavy metal ions are introduced. Because metal aluminum is relatively active...

AI Technical Summary

Problems solved by technology

Due to the high surface energy of the newly exposed surface of CMP, it is very easy to adsorb the surrounding large particles and metal ions, and it will form chemical adsorption with the sticky dirt in a short time after CMP, which is difficult to remove and cause pollution; The uneven distribution of polishing liquid and the blocking of large particles adsorbed on the surface, therefore, the chemical corrosion is uneven on the surface, forming non-uniform pits, and the oxidation is also uneven, forming non-uniform oxidation, which reduces the surface quality and fails to meet the requirements

The traditional CMP post-treatment method is to lift the polishing disc and rinse it with deionized water after the end of CMP. Due to the time lag and only rinse with deionized water, the treatment effect is not ideal, and the contamination by organic matter, large particles and metal ions is serious