A reliable control system for measurement on film thickness in copper chemical mechanical planarization system

Abstract

In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules' GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The result shows that the control system is running stably after repeated tests and practical operations for a long time.

A decoupling calculation method of separating temperature component from the nano-scale metal film thickness measurement output by the eddy current sensor

“…sensors have been widely used in micro-nano measurement fields, such as metal film thickness [2,3], lubricant oil film thickness [4,5], vibration monitoring [6], and micro displacement [7], due to the advantages of non-contact measurement, non-destructive testing [8,9], high resolution and strong environmental adaptability. For example, in the copper (Cu) chemical mechanical planarization (CMP) process [10], the eddy current sensor can be used to measure the Cu film thickness variation in-situ for achieving a flat wafer surface with a high quality.…”

Motor Power Signal Analysis for End-Point Detection of Chemical Mechanical Planarization

“…EPD technology is a big challenge of the CMP process [ 7 ], because in-situ EPD is difficult to perform under the actual process conditions [ 1 ]. At present, various EPD methods [ 5 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ] have been proposed, such as optical reflectance, frictional force, pad temperature, Cu-ion concentration, and eddy current. In the self-developed CMP system, the eddy current method [ 13 ] has been used to develop independently an in-situ measurement module for detecting the Cu layer thickness variation [ 12 ].…”

An <i>In Situ</i> End-Point Detection System Using Motor Power Signal for Chemical Mechanical Planarization Process

“…Under such conditions, in-situ EPD is difficult to perform [4]. At present, various EPD methods [5,[7][8][9][10][11][12][13] have been proposed, such as optical reflectance, pad temperature, Cu-ion concentration, eddy current, and frictional force. In this study, we attempted to use the motor power signal of the polishing platen for detecting the end point of removal of the metal layer during the CMP process, based on the frictional method.…”