硅片表面球形粒子散射研究

为求解硅片表面微小粒子在任意线偏振平面入射光照射下的散射光光强分布,选择了基于Mie散射的杨氏模型为依据,推导了该模型下散射光强空间分布的计算方法,并给出了0.54 μm球形粒子在垂直、倾斜入射下光强空间分布的模拟计算结果,以及入射平面第一象限内散射光强与国外已发表实验结果的比较.     

掠出射X射线荧光谱仪性能评测

通过对GaAs(100)抛光晶片在相同条件下掠出射X射线荧光实验的可重复性研究,并结合常规光源与同步辐射光源X射线掠出射荧光实验结果的对比,证明自行研制的掠出射X射线荧光平台可重复性较好,稳定性较高,实验方法的设计是合理的。理论计算与实验曲线符合的较好,证明掠出射X射线荧光实验中用单晶的全反射临界角标定掠出射角度的方法是可行的。用标准晶片掠出射X射线荧光曲线的微分评测了实际角发散度的大小。     

A new spectrometer for grazing incidence X-ray fluorescence for the characterization of Arsenic implants and Hf based high-k layers

Grazing Incidence X-ray Fluorescence Analysis (GIXRF) is a powerful technique for depth-profiling and characterization of thin layers in depths up to a few hundred nanometers. By measurement of fluorescence signals at various incidence angles Grazing Incidence X-ray Fluorescence Analysis provides information on depth distribution and total dose of the elements in the layers. The technique is very sensitive even in depths of a few nanometers. As Grazing Incidence X-ray Fluorescence Analysis does not provide unambigous depth profile information and needs a realistic input depth profile for fitting, in the context of the EC funded European Integrated Activity of Excellence and Networking for Nano and Micro-Electronics Analysis (ANNA) Grazing Incidence X-ray Fluorescence Analysis is used as a complementary technique to Secondary Ion Mass Spectrometry (SIMS) for the characterization of Ultra Shallow Junctions (USJ).     

Optical inspection system with tunable exposure unit for micro-crack detection in solar wafers

Micro-cracks are a major cause of wafer breakage in the solar wafer manufacturing process. Furthermore, the existence of micro-cracks may lead to electrical failure in the post-fabrication inspection of solar cells and solar modules. Thus, the reliable detection of micro-cracks is an important concern in the photovoltaic industry. Accordingly, the present study proposes a novel micro-crack inspection system comprising a near infrared light source, a CCD camera and a tunable exposure unit. In the proposed system, the intensity of the light transmitted through the wafer is sensed by a photodetector and the exposure time of the CCD camera is tuned accordingly in order to maximize the contrast of the CCD image; thereby improving the performance of the crack detection process. The experimental results show that the proposed system enables the reliable detection of micro-cracks in solar wafers with a thickness of up to 240 μm within 1 s. In other words, the system provides an ideal solution for on-line micro-crack inspection applications in the photovoltaic industry.     

应力预释放对单晶硅片的压痕位错滑移的影响

单晶硅片的压痕位错在一定温度下的滑移距离反映了硅片的机械强度. 压痕位错的滑移是受压痕的残余应力驱动的, 因此研究残余应力与位错滑移之间的关系具有重要的意义. 本文首先采用共聚焦显微拉曼术研究了单晶硅片压痕的残余应力经过300或500 ℃ 热处理后的预释放, 然后研究了上述应力预释放对压痕位错在后续较高温度(700–900 ℃)热处理过程中滑移的影响. 在未经应力预释放的情况下, 压痕位错在700–900 ℃热处理2 h后即可滑移至最大距离. 当经过上述预应力释放后, 位错在900 ℃热处理2 h后仍能达到上述最大距离, 但位错滑移速度明显降低; 而在700和800 ℃时热处理2 h后的滑移距离变小, 其减小幅度在预热处理温度为500 ℃时更为显著. 然而, 进一步的研究表明: 即使经过预应力释放, 只要足够地延长700和800 ℃ 的热处理时间, 位错滑移的最大距离几乎与未经预应力释放情形时的一样. 根据以上结果, 可以认为在压痕的残余应力大于位错在某一温度滑移所需临界应力的前提下, 压痕位错在某一温度滑移的最大距离与应力大小无关, 不过达到最大距离所需的时间随应力的减小而显著增长.     

分光光度法测量铝镓氮外延片中的铝含量

采用熔融的氢氧化钠刻蚀在蓝宝石衬底上生长的铝镓氮外延层,用深紫外光致发光光谱仪测量铝镓氮的荧光光谱来控制铝镓氮层的刻蚀深度,用盐酸将含铝氢氧化钠中和并调节至酸性(pH1~2)后转移至250 mL的容量瓶内定容,用铬天青S络合显色,用分光光度计在546 nm处测定吸光度来确定铝的浓度。该法测量结果的相对标准偏差为1.1%(n=5),加铝标准溶液做回收试验,回收率为96%~103%。该法可用于铝镓氮外延片中铝含量的准确测量。     

Study micromechanism of surface planarization in the polishing technology using numerical simulation method

With the development of semiconductor industry, the chemical mechanical polishing technology has already became the main stream method of realize the surface global flatness. In order to understanding physical essence underlying this technology, the author carried out nanometer polishing experiment of silicon wafer using molecular dynamics (MD) simulation method. The simulation result shows that larger slurry grain generate much more vacancy, dislocation, larger residual stress and intensive plastic deformation than that of small one although the larger grain acquire better surface quality.     

CdTe量子点功能化玻片的制备及其对Pb2+浓度的检测

通过羟基化和氨基硅烷化处理,得到表面接枝氨基的玻片载体。水相合成巯基乙酸修饰的CdTe量子点(CdTe-TGA),采用EDC/NHS活化反应,将量子点偶联到氨基化玻片表面,制备出具有荧光性能的功能化玻片。考察了量子点与EDC的量比、活化时间、偶联温度以及偶联时间对偶联效果的影响。结果表明,在量子点与EDC的量比为1:30、活化时间1 h、偶联温度30 ℃、偶联时间4 h条件下获得的功能化玻片具有最佳的荧光性能。将该条件下制备的功能化玻片用于水溶液中Pb²⁺的浓度检测,得到玻片相对荧光猝灭强度随Pb²⁺浓度变化的线性曲线,线性范围为1.0×10^-9~4.0×10^-8mol·L^-1,检出限为3.8×10^-9mol·L^-1,且具有良好的选择性。该方法可以灵敏而准确地检测Pb²⁺浓度。     

In situ surface topography measurement method of granite base in scanning wafer stage with laser interferometer

Topography of a granite surface has an effect on the vertical positioning of a wafer stage in a lithographic tool, when the wafer stage moves on the granite. The inaccurate measurement of the topography results in a bad leveling and focusing performance. In this paper, an in situ method to measure the topography of a granite surface with high accuracy is present. In this method, a high-order polynomial is set up to express the topography of the granite surface. Two double-frequency laser interferometers are used to measure the tilts of the wafer stage in the X- and Y-directions. From the sampling tilts information, the coefficients of the high-order polynomial can be obtained by a special algorithm. Experiment results shows that the measurement reproducibility of the method is better than 10 nm.