Method for calibrating incident energy density of front surface of wafer

Abstract

The invention relates to a method for calibrating the incident energy density of the front surface of a wafer, which comprises the following steps of: providing an undoped wafer, annealing by adopting laser with different energy densities, controlling the uncalibrated energy density by a feedback loop, and providing the measurement of the incident energy density in any unit; in the annealing process, surface roughness testing is conducted on a wafer through an AFM, and a threshold value change point at the beginning of surface melting and the corresponding actual incident energy density are obtained; and according to the incident energy density of any unit and the actual incident energy density corresponding to the threshold value change point, incident energy density calibration is carried out. According to the method, the incident laser pulse energy density is calibrated by using the sudden threshold change of the surface roughness measured by the AFM at the beginning of wafer surface melting; performing incident ED period monitoring on sub-melt boron doping activation of the silicon substrate at the temperature of 1300 DEG C; tool and process matching is performed using epitaxial regrowth of an amorphous doped silicon phosphorus layer at 1200 DEG C or below, and the matching is in the range of 1% of the energy density.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for calibrating the front incident energy density of a wafer. Background technique [0002] Millisecond laser pulse annealing (mSec, LSA) is adopted by many CMOS manufacturing equipment for dopant activation and gate reliability. The process uses a 10kHz fast pyrometer to measure the surface temperature of the wafer, which suppresses large differences in surface temperature. It is well known that annealing at high temperature is often required in order to activate dopant atoms and repair the damage caused by ion implantation. At the same time, the thermal budget of the annealing process must be small to reduce the transient enhanced diffusion effect (Transient-Enhance Diffusion, TED) of dopant atoms in the silicon device during the activation process, thereby protecting the structure of the abrupt junction, thereby effectively Control short channel ...

AI Technical Summary

Problems solved by technology

[0007] The present invention is aimed at the limited selection of ultra-high-speed pyrometers in the traditional LSA in the prior art, and the large temperature change rate caused by the optical and thermal characteristics related to the layout, which brings some challenges to shortening the annealing time, and due to the doping Sub-melt nanoscale activation of dopant at 1200 °C or lower is inefficient and unreliable, and more accurate methods are needed to monitor defects such as NLA processes at lower energy densities (Energy Density, ED) to provide a calibration Wafer Front Incident Energy Density Method

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