New effects of modified illumination in optical lithography

In optical lithography the most fine and isolated dark line is obtained at the phase-shifter edge of a chromeless phase-shifting mask, but only closed-loop patterns can be formed. An easy method for eliminating the useless dark line at the phase-shifter edge by combining modified illumination technologies is proposed. Using a modified light source, which is arranged along one axis (x or y) of the light source area, the resultant optical intensity is different in the x and y directions. A fine resist pattern of 0.15 μm produce along only one direction of the phase-shifter's edge is demonstrated     

温度气压对高分辨力光刻物镜像质影响研究

分析温度气压对物镜光学材料、透镜厚度间隔,以及空气折射率的影响,并用空气折射率对物镜像质影进行模拟计算。研究表明物镜焦面产生较大漂移,对僧率有一定影响,而对畸变影响较小,指出对物镜进行温度气压控制补偿是必要的。     

Application of resist-profile-aware source optimization in 28 nm full chip optical proximity correction

As technology node shrinks, aggressive design rules for contact and other back end of line (BEOL) layers continue to drive the need for more effective full chip patterning optimization. Resist top loss is one of the major challenges for 28 nm and below technology nodes, which can lead to post-etch hotspots that are difficult to predict and eventually degrade the process window significantly. To tackle this problem, we used an advanced programmable illuminator (FlexRay) and Tachyon SMO (Source Mask Optimization) platform to make resist-aware source optimization possible, and it is proved to greatly improve the imaging contrast, enhance focus and exposure latitude, and minimize resist top loss thus improving the yield.     

Determination of proximity effect parameters by means of CD-linearity in sub 100 nm electron beam lithography

Along with the introduction of the 32 nm technology node in the next years, the methods for correcting the proximity effect face certain limitations of measurement performance and the underlying point spread function based models themselves. To extend these methods to future technology nodes, they have to rely on more generalized coherences between nominal and measured feature sizes than just the absolute measurement values. In this work, a method is introduced to determine the forward scattering range and backward scattering ratio by printing isolated lines with various line widths and pre-assigned variable exposure doses. The line widths are then measured using standard inline scanning electron microscopy and correlated to their nominal values. This is done in terms of linearity to find the best match between the input parameters of the methodology and the intrinsic values of the resist-substrate system. A comparison between simulated and experimental results conclude that significant line width nonlinearities will occur, when relying on conventional methodologies especially for feature sizes below 40 nm.     

Limitation of the Kirchhoff boundary conditions for aerial imagesimulation in 157-nm optical lithography

The aerial images of half-wavelength features with 0° and 180° phases obtained by using the Kirchhoff boundary conditions are compared with those obtained by using rigorous electromagnetic field computation for 248-nm lithography and 157-nm lithography. The discrepancies between the aerial images computed by the two methods are large at both wavelengths, but they are much larger for TM polarization at the wavelength λ=157 nm. These discrepancies are due to diffraction effects in the aperture regions, which are more pronounced at λ=157 nm because of the larger ratio of the thickness of the chromium absorber to the wavelength required at λ=157 nm for a given attenuation factor. This shows that diffraction effects in the aperture regions must be included when simulating aerial images in 157-nm lithography     

Challenges in using optical lithography for the building of a 22 nm node 6T-SRAM cell

FinFET devices are one of the most promising candidates for enabling SRAM scaling beyond the 32 nm technology node. This paper will describe the challenges faced when setting up the patterning processes in the front-end part of a 22 nm node 6T-SRAM cell. Key in this work was achieving the required CD and profile target specs for the fin and the gate level. Also, the implant levels, though still a 450 nm pitch, turned out to be more difficult than expected because of the underlying topography. All this work resulted in the first electrically functional 22 nm node SRAM cell, with the contact and metal level exposed on the ASML EUV α-demo tool.     

轴向温度梯度对红外透镜光学性能的影响

运用有限元分析软件ANSYS建立了透镜组件的有限元模型,并对其进行热应力分析。用Zernike多项式对变形后的镜面面形进行拟合,并将得到的Zernike系数导入光学设计软件ZEMAX中,分析了轴向温度梯度对红外透镜光学性能的影响。结果表明:透镜面形的PV值、RMS值以及透镜表面曲率半径的变化量(ΔR)均随轴向温度梯度的增大而增大;轴向温度梯度使透镜面形发生了变化,从而导致了透镜光学性能的下降。     

Broad-band wavelength conversion based on cross-gain modulation and four-wave mixing in InAs-InP quantum-dash semiconductor optical amplifiers operating at 1550 nm

Wavelength conversion based on four-wave mixing (FWM) and cross-gain modulation (XGM) is experimentally demonstrated for the first time in a 1550-nm InAs-InP quantum-dash semiconductor optical amplifier. Continuous-wave FWM with a symmetric conversion efficiency dependence on detuning direction and FWM mediated short-pulse wavelength conversion are demonstrated. Using XGM, we have successfully implemented short-pulse wavelength conversion over 10 THz and error-free data conversion of a 2.5-Gb/s data sequence over 7.5 THz. The pulsed XGM experiments suggest that adjacent regions within an inhomogeneously broadened gain spectrum are partially coupled which increases the operational bandwidth, but at the expense of speed.     

Estimating oxide thickness of tunnel oxides down to 1.4 nm usingconventional capacitance-voltage measurements on MOS capacitors

High-frequency capacitance-voltage (C-V) measurements have been made on ultrathin oxide metal-oxide-semiconductor (MOS) capacitors. The sensitivity of extracted oxide thickness to series resistance and gate leakage is demonstrated. Guidelines are outlined for reliable and accurate estimation of oxide thickness from C-V measurements for oxides down to 1.4 nm     

Effect of laser chirp on optical systems?initial tests using a 1480 nm DFB laser

Initial assessment of the effect of laser ?chirp? on optical systems is described. Measurements of the wavelength shift and its effect on the received pulse after 4 km and 80 km of dispersive fibre are presented. The results are in good agreement with simple modelling, which predicts no penalty for this system Further tests are needed to determine whether this behaviour is typical.     

Effect of deposition and annealing conditions on the optical properties of amorphous silicon

The spectral characteristics of the refractive index and the extinction coefficient in the range 0.6–2.0 eV for amorphous silicon films prepared by electron-beam evaporation with variation of the substrate temperature, deposition rate, and annealing temperature in air are presented. The results obtained are discussed on the basis of the changes in the Penn gap energy as a function of the indicated preparation and treatment conditions. Fiz. Tekh. Poluprovodn. 32, 879–881 (July 1998)     

Effect on skywave field strengths of proximity to a discontinuity in the Earth's electrical properties

A theoretical formula amenable to numerical computation of this effect is derived in a simple and generalised fashion from an extension of an approximate method which was developed by Feinberg for the ground-to-ground propagation over an inhomogeneous flat earth.     

Models to predict the operating temperature of different photovoltaic modules in outdoor conditions

The operating temperature of photovoltaic modules under real operating conditions is important information when designing and sizing those systems. This paper proposes new models to predict this temperature for different technology modules under the climate conditions of southern Spain using meteorological parameters. The proposed models are hourly and instantaneous. Those models are compared with previous models existing in the literature. The results obtained show that because of the thermal inertia of the modules, only the proposed hourly models allow the average temperature of the modules to be determined accurately. The temperature of the modules can be predicted using the two‐parameter hourly model proposed in this paper with a mean absolute percentage error less than 6.0% for the technologies tested. Copyright © 2014 John Wiley & Sons, Ltd.     

工艺条件对柔性衬底ITO薄膜光电性能的影响

采用直流磁控溅射法在柔性衬底上镀制ITO透明导电薄膜,全面研究了薄膜厚度、氧气流量、溅射速率、溅射气压和镀膜温度等工艺条件对ITO薄膜光电性能的影响。结果表明,当膜厚大于80nm、氧氩体积比为1∶40、溅射速率为5nm/min、溅射气压在0.5Pa左右、镀膜温度为80～160℃时,ITO薄膜的光电性能较好,其电阻率小于5×10–4?·cm、可见光透光率大于80%。     

Effect of operating conditions on reverse gate current of junction f.e.t.s

With some types of nchannel junction f.e.t.s the measurement of gate leakage current under operating conditions (with a current flowing in the channel) has shown a very much higher value than would be expected from the maker's specification of IGSS. The excess gate current which flows at higher channel voltage is proportional to the drain current and has a small negative temperature coefficient.     

Experimental validation of a thermal modelling method dedicated to multichip power modules in operating conditions

In this paper, we present an implementation of a thermal modelling method applied to a multichip module used as a power converter. Analytical functions of thermal impedances, with original formulations for the mutuals are defined. They are derived from 3D thermal simulations and experimental validations with direct chips temperature measurements. Finally, simulations are performed in order to improve the capability of our model to assess, with fast computation, the thermal constraints applied on the multichip module in a real operating condition.     

沟道宽度对65nm金属氧化物半导体器件负偏压温度不稳定性的影响研究

随着MOS器件尺寸缩小,可靠性效应成为限制器件寿命的突出问题.PMOS晶体管的负偏压温度不稳定性（NBTI）是其中关键问题之一.NBTI效应与器件几何机构密切相关.本文对不同宽长比的65nm工艺PMOSFET晶体管开展了NBTI试验研究.获得了NBTI效应引起的参数退化与器件结构的依赖关系,试验结果表明65nm PMOSFET的NBTI损伤随沟道宽度减小而增大.通过缺陷电荷分析和仿真的方法,从NBTI缺陷产生来源和位置的角度,揭示了产生该结果的原因.指出浅槽隔离（STI）区域的电场和缺陷电荷是导致该现象的主要原因.研究结果为器件可靠性设计提供了参考.     

Study of SILC and interface trap generation due to high fieldstressing and its operating temperature dependence in 2.2 nm gatedielectrics

Reports study of metal-oxide-semiconductor (MOS) capacitors with 2.2 nm dry and N₂O grown gate dielectrics. Interface trap generation during constant voltage stressing at different operating temperatures (from 22°C to 90°C) has been investigated. The effect of nitrogen annealing (20 min) at 400°C on high temperature stress-induced interface traps was also studied     

Prediction of rain effects on earth-space communication links operating in the 10 to 35 GHZ frequency range

This paper reviews the effects of precipitation on earth-space communication links operating the 10 to 35 GHz frequency range. Emphasis is on the quantitative prediction of rain attenuation and depolarization. Discussions centre on the models developed at Virginia Tech. Comments on other models are included as well as literature references to key works. Also included is the system level modelling for dual polarized communication systems with techniques for calculating antenna and propagation medium effects. Simple models for the calculation of average annual attenuation and cross-polarization discrimination (XPD) are presented. Calculation of worst month statistics are also presented.