Silica sol used in CMP polishing

With the rapid development of the integrated circuit industry, IC manufacturing has developed a trend of nanometer feature size, three-dimensional film structure and multilayer metal wiring, which has increasingly stringent requirements for the global flatness of the surface of various materials in the IC structure, especially the requirements for each layer of materials in the interconnect structure must be implemented by chemical mechanical polishing flattening processing.

Chemical mechanical polishing technology is a combination of chemical action and mechanical action technology, in fact, its microscopic process is quite complex, and there are many influencing factors. The polishing fluid affects both the chemical and mechanical processes of CMP, which is one of the decisive factors affecting the quality of CMP.

Silica sol is a milky or light blue transparent solution, which is a colloidal dispersion of nano SiO2 (silica) particles dispersed in water (or organic solvent), also known as silica solution industrial silica sol is divided into acidic silica sol, neutral silica sol and alkaline silica sol according to pH.

At present, silica sol is widely used as a common abrasive in the CMP polishing process of various materials, metal polishing, semiconductor material polishing, sapphire polishing, polishing of various substrate materials, silica sol is the most common abrasive.

The Mohs hardness of silica sol is not high, so for general semiconductor materials, metal materials, ceramic materials, etc., silica sol as an abrasive, in the CMP polishing process, will not easily leave scratches on the surface of the polishing material, and can achieve high surface accuracy.

It is the most commonly used abrasive for high precision polishing abrasive in CMP polishing.