Wafer polishing control method and polishing system

Abstract

The present invention relates to a wafer polishing control method and a polishing system, and provides a wafer polishing control method and a polishing system using the same, which can be controlled so as to make the thickness distribution of the polishing layer of the wafer uniform at the polishing end time point. The method includes: polishing step, polishing the polishing layer of the wafer; light irradiation step, irradiating light to the first position and the second position of the polishing layer of the wafer; light receiving step, receiving the first position of the wafer The first reflected light from the first reflected light and the second reflected light from the second position; the pressure adjustment step adjusts the pressure of the wafer according to the zone, so as to eliminate the first optical interference signal from the first reflected light and the Variation of the second optical interference signal of the second reflected light.

Description

technical field [0001] The present invention relates to a wafer polishing control method using phase difference detection using multi-wavelength light and a polishing system using the same. A polishing control method and a system utilizing the same can be used to accurately adjust the thickness of the polishing layer in real time through phase difference control of multi-wavelength light. Background technique [0002] Chemical Mechanical Polishing (CMP) equipment is an all-round flat surface that eliminates the level difference between the cell area and the peripheral circuit area caused by the unevenness of the wafer surface caused by repeated masking, etching, and wiring processes during the semiconductor element manufacturing process. It is a device used to perform precision polishing on the wafer surface by improving the surface roughness of the wafer due to separation of contact / wiring film for circuit formation and high-integration components. [0003] In this CMP dev...

AI Technical Summary

Problems solved by technology

[0009] Furthermore, unlike Figure 1b and Figure 1c As shown, there is a problem in the past that there is no method to detect the thickness of the oxide film except for calculating the number of times the interference light peak (singular value, singular point) for one wavelength is reached and the interference light period is calculated.

[0010] Furthermore, the oxide layer deposited on the surface of the wafer W by means of a CVD process or the like is often formed thin at the edges and thick at the center. Therefore, there is a problem in that the waveform of the interference light reflected from the thicker portion at the center is accurately formed. Detecting the end of polishing is extremely difficult

[0011] In addition, since large and small thicknesses are detected at the same time according to the pattern on the wafer surface, it is difficult to grasp the thickness, so there is a problem of measuring the thickness of the polishing layer of the wafer in real time and controlling the polishing layer of the wafer uniformly in the polishing process. Thickness is more difficult

[0012] In other words, in the polishing process of the wafer, even if the thickness of the polishing layer of the wafer deviates, in order to compensate for the thickness deviation of the polishing layer of the wafer, the technology of adjusting the pressure of the polishing head according to the position has been proposed in the past, but it is necessary to accurately obtain the polishing layer of the wafer. The time required for the thickness has limitations in real-time control. During the time required to obtain the thickness of the polishing layer, the polishing layer has been worn, so there is a limitation that it becomes difficult to adjust the deviation of the thickness of the polishing layer in real time.

[0013] In addition, the time required to perform a polishing process on a wafer is very short, approximately 30 seconds to 60 seconds. In the polishing process, the optical interference signal reflected by the oxide layer only passes through 2 to 3 cycles, so the polishing During the process, there are limitations in the pressure control of the polishing head for real-time adjustment of the thickness of the polishing layer

Images