A chemical mechanical polishing solution and its application

Abstract

The present invention provides a chemical mechanical polishing liquid, comprising silica abrasive particles, a nitrogen-containing heterocyclic compound containing one or more carboxyl groups, and an ethoxylated butoxylated alkyl alcohol. The present invention also provides an application of the above chemical mechanical polishing liquid in the polishing of silicon dioxide, polysilicon and silicon nitride. The polishing rate of the polishing solution of the present invention for silicon nitride is far greater than that for silicon dioxide and polysilicon, so that it can be well applied to chemical mechanical polishing with silicon dioxide / polysilicon as the stop layer. The amount of oxide and polysilicon removed from the surface of the substrate during the polishing process can be effectively controlled.

Description

technical field [0001] The invention relates to the field of chemical mechanical polishing, in particular to a chemical mechanical polishing liquid and its application. Background technique [0002] In the production process of the semiconductor chip, the step of removing the silicon nitride layer is performed at various stages, for example, in the step of forming the element separation structure, the silicon nitride layer as a barrier layer is removed. However, this removal step is usually carried out at a high temperature of about 150° C. by a wet etching process using, for example, a phosphoric acid / nitric acid mixed solution, and chemical mechanical polishing is rarely used. [0003] At present, the method for isolating each element in a semiconductor device is mainly a shallow trench isolation (STI) process, that is, a silicon nitride layer is first formed on a silicon substrate, a shallow trench is formed by etching or photolithography, and then a dielectric is deposit...

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Problems solved by technology

However, the existing chemical mechanical polishing fluid does not have the polishing rate selectivity of the three substances of silicon nitride / silicon oxide / polysilicon as mentioned above.

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