Chemical-mechanical grinding end-point detecting method and system based on shallow trench isolation technology

Abstract

The embodiment of the invention provides a chemical-mechanical grinding end-point detecting method based on a shallow trench isolation technology. The chemical-mechanical grinding end-point detecting method comprises the following steps of: establishing a function equation between the relative sliding speed of a wafer surface element and a grinding pad and the friction force born by the element; solving the functional equation, substituting the friction born by the element into the torque formula of the grinding pad, and establishing a functional relation among a wafer, the adjustable torque of the grinding pad and the mechanical parameter of a grinding driving device; and according to the difference of the friction coefficients caused by material differences, analyzing the influence of the surface characteristic of the grinding pad on the appearance change of the wafer, and recognizing the grinding end point by virtue of the functional relation between the adjustable torque of the grinding pad and the mechanical parameter of the grinding driving device, thus realizing the detection of the end point. According to the scheme provided by the invention, the torque change is analyzed by surveying the friction factor between the wafer and the grinding pad, the mutual action relation between the wafer and a random-fluctuation rough pad in the manufacture procedure of the grinding process is deeply analyzed, and the difference of the grinding removing rate caused by the material difference can be recognized directly by the torque of the grinding pad, so that the detection of the end point can be realized flexibly.

Description

technical field [0001] The invention relates to the technical field of CMP manufacturing process and CMP modeling, in particular, the invention relates to a chemical mechanical polishing end point detection method and system based on shallow trench isolation technology. Background technique [0002] At present, with the continuous expansion of integrated circuit wafer size and the continuous reduction of chip feature size, the process of process nodes below 45nm node, including 32nm, 22nm and 16nm, is proposed for the research and application of design for manufacturability (DFM, Design for manufacturability). new requirements and challenges. Chemical Mechanical Polishing (CMP, Chemical Mechanical Polishing), as a key link in the DFM process solution, has become the core technology that has attracted the attention of the industry in the most advanced semiconductor industry. [0003] Shallow Trench Isolation (STI, Shallow Trench Isolation) technology is a new field isolation...

AI Technical Summary

Problems solved by technology

[0006] (1) Endpoint detection of optical reflectivity. This method uses the light reflectivity change of the wafer surface transition from silicon oxide film to silicon nitride film to judge the polishing end point, so it is simple and easy to implement, but the stability is not high;

[0007] (2) Endpoint detection of ion concentration in the grinding waste liquid. This method accurately detects the end point by detecting the concentration change of nitrogen ions in the waste liquid. Therefore, it has a high accuracy rate, but requires an additional ion detector, and the cost is high;

[0009] At present, although the research on the above methods is relatively sufficient, all technologies are actually applied to industrial production practice and developed into products, only the endpoint detection technology based on the change of the drive motor current, other technologies are still in the stage of laboratory demonstration

Images