In the cutting-edge semiconductor manufacturing domain targeting nodes below 40 nm, laser spike annealing (LSA) has emerged as a key technology. As the industry relentlessly continues to pursue miniaturization and performance enhancement, LSA plays a critical role in fabricating high-performance logic devices by enabling precise dopant activation in wafers. However, existing LSA processes—commonly employing high-energy density laser beams at large incident angles—frequently result in highly non-uniform temperature distributions, particularly in the edge regions of wafers. This leads to serious challenges such as edge burn and wafer cracking. Edge burn damages the wafer edges and introduces defects that degrade electrical properties, whereas wafer cracking renders wafers unusable, leading to material and time losses. These issues significantly undermine wafer integrity, quality, and production yield, increasing costs and delaying deliveries. Thus, there is an urgent need to develop innovative and effective approaches for optimizing the scanning trajectory design and temperature control parameters. The primary objective of this study aims to enhance temperature uniformity across the wafer, with a particular emphasis on improving thermal stability in the edge regions. Improvement is critical for ensuring reliable, high-performance semiconductor manufacturing processes and meeting the industry’s increasing demands for advanced devices.

This research introduces a comprehensive and systematic methodology. First, a novel scanning trajectory was designed. In contrast to the conventional straight-line scanning approach, a three-segment tangent line-arc-line trajectory was adopted. This design mitigates direct laser irradiation on the wafer edges—a common issue with straight-line scanning—while also reducing vibration problems associated with purely arc-based trajectories. By precisely defining parameters such as the light spot length, outer reference circle radius, and the azimuth angle of the initial trajectory, a detailed trajectory planning method was established. Subsequently, the relationships between the azimuth angle and key optical factors, such as incident light intensity and absorptance, were thoroughly investigated through geometric and polarization optical analyses. Using these relationships and considering the maximum energy absorbed at the wafer edge, an optimal azimuth angle range was calculated. In addition, a power-switching mechanism was integrated into the system. This mechanism dynamically and precisely adjusts the laser power in real time as the laser spot moves across the wafer boundary. Finally, to address the persistent issue of temperature overshoot during open/closed-loop switching processes, a second-order S-curve temperature trajectory was designed. This temperature trajectory allows for smooth, gradual changes in temperature response, optimizing temperature control performance.

The experimental findings clearly highlight the effectiveness of the proposed method. Regarding azimuth angle optimization, a gradual increase in the azimuth angle from a relatively small value to the optimal range of 57.3°?90° results in a significant and continuous reduction in the peak temperature at the wafer edge during the first scanning. This demonstrates that proper adjustment of the azimuth angle can effectively regulate the interaction between the laser beam and the wafer edge. By increasing the azimuth angle, the incident light intensity and absorptance at the wafer edge are optimized, effectively suppressing excessive heat generation in the edge region. In terms of temperature trajectory optimization, the introduction of the second-order S-curve temperature trajectory yields highly favorable results. It effectively mitigates the temperature overshoot problem commonly encountered in traditional control methods. This approach stabilizes the temperature within a reasonable range and enhances the overall temperature control stability during the scanning process.

This research represents a significant advancement in LSA for semiconductor manufacturing. By addressing the persistent issue of edge burn, the study offers a set of highly effective solutions that significantly enhance the quality and reliability of semiconductor production processes. The meticulous optimization of scanning trajectory parameters, combined with the innovative design of the temperature trajectory, leads to a marked improvement in wafer temperature uniformity. This, in turn, enhances the processing quality and performance of high-performance logic devices. Although the experiments were conducted under specific ion implantation conditions, the methodologies and insights derived from this study provide valuable references for a broader range of semiconductor manufacturing processes. Furthermore, the proposed approach has significant potential for application in other laser scanning technologies. The ability to improve processing efficiency and quality opens up new avenues for technological advancement in the manufacturing sector.