Grinding method

Abstract

The invention discloses an interface monitoring method used during chemical and mechanical grinding. The method comprises the following steps of: providing a wafer, wherein the surface of the wafer is provided with a lining layer and a layer to be ground which is arranged on the surface of the lining layer; chemically and mechanically grinding the layer to be ground, monitoring the reflectivity information of a ground surface in a chemical and mechanical grinding process and drawing a curve of reflectivity and grinding time; calculating and recording a gradient at the end point of the curve at a fixed interval; and determining whether chemical and mechanical grinding needs stopping according to a recorded gradient value. The method has the advantages that: the grinding situation is determined by a measure for detecting the change of the gradient value instead of a method taking a reflectivity curve as a judgment standard in the prior art and stops are made in time on an interface or at other specified positions, so that monitoring failure is avoided.

Description

【Technical field】 [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for monitoring the grinding end point during grinding. 【Background technique】 [0002] In the chemical mechanical polishing (CMP) process, it is often encountered that the grinding of a certain target layer stops at the interface between the layer and the supporting layer below. Since the chemical mechanical polishing process uses mechanical polishing and chemical reaction to treat the interface at the same time, the polishing liquid used is usually easy to react with the substance of the target layer to be polished, but not easy to react with the substance of the underlying support layer. Therefore, during the process of grinding the target layer, the reflectivity of the surface is always increased, and once another layer underneath is exposed, the reflectivity of the surface decreases. This principle is used in the commonly used grinding process, and the m...

AI Technical Summary

Problems solved by technology

In this case, the monitoring program will mistakenly think that the grinding process has not yet reached the interface and continue to implement the grinding process, which will eventually lead to endless grinding, with serious consequences

[0005] Therefore, the disadvantage of the existing technology is that it can only be applied to the situation where the reflectivity curve at the interface changes gently, and for the situation where the reflectivity curve changes sharply at the interface, the monitoring program may fail, resulting in the endless grinding process. , with serious consequences

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