Pattern evolution in shallow trench isolation chemical mechanical planarization via real-time shear and down forces spectral analyses

This study explores the transition of force spectral fingerprints of shallow trench isolation chemical mechanical planarization during early evolution of wafer topography and layer transition from silicon dioxide to silicon nitride. Polishing was done on a polisher and tribometer capable of measuring shear force and down force in real-time. Fast Fourier Transformation is performed to convert the force data from time domain to frequency domain and to illustrate the spectral amplitude distribution of the force. Such frequency spectra provide in-depth insights into the interactions among abrasive particles, pad and wafer. Shallow trench isolation patterned wafers are over-polished using cerium oxide slurry. Results show that shear force increases during polishing when the silicon dioxide layer is removed thus exposing the silicon nitride layer. Unique and consistent spectral fingerprints are generated showing significant changes in several fundamental peaks during the early evolution of wafer topography and subsequent layer transition to silicon nitride polishing. Variance of force is also plotted to show the progression of pattern evolution. Results show that a combination of unique spectral fingerprinting, coefficient of friction as well as analyses of force and its variance (based on shear and down force) can be used as to monitor in real-time the polishing progress during shallow trench isolation chemical mechanical planarization.     

半导体器件硅衬底化学机械平坦化研究

主要对分立器件硅衬底化学机械平坦化(CMP)进行了研究。首先通过正交实验方法研究活性剂、螯合剂、磨料浓度和有机碱对硅材料去除速率的影响,得出活性剂体积分数对去除速率的影响最大,并且研究出去除速率最快的抛光液的最优配比,去除速率可以达1 410nm/min。同时平坦化后的硅衬底具有良好的表面状态:表面粗糙度仅为0.469nm,表面总厚度变化小于工业标准指标5μm。在考虑工艺影响的情况下,硅衬底制造双极型晶体管的成品率达到90%以上,满足工业成品率要求。     

Surface Control of Planarization Layer on Embossed Glass for Light Extraction in OLEDs

We developed a highly refractive index planarization layer showing a very smooth surface for organic light‐emitting diode (OLED) light extraction, and we successfully prepared a highly efficient white OLED device with an embossed nano‐structure and highly refractive index planarization layers. White OLEDs act as an internal out‐coupling layer. We used a spin‐coating method and two types of TiO₂ solutions for a planarization of the embossed nano‐structure on a glass substrate. The first TiO₂ solution was TiO₂ sol, which consists of TiO₂ colloidal particles in an acidic aqueous solution and several organic additives. The second solution was an organic and inorganic hybrid solution of TiO₂. The surface roughness (R_a) and refractive index of the TiO₂ planarization films on a flat glass were 0.4 nm and 2.0 at 550 nm, respectively. The J–V characteristics of the OLED including the embossed nano‐structure and the TiO₂ planarization film were almost the same as those of an OLED with a flat glass, and the luminous efficacy of the aforementioned OLED was enhanced by 34% compared to that of an OLED with a flat glass.     

低磨料浓度的碱性铜抛光液平坦化性能的研究

A novel alkaline copper slurry that possesses a relatively high planarization performance is investigated under a low abrasive concentration.Based on the action mechanism of CMP,the feasibility of using one type of slurry in copper bulk elimination process and residual copper elimination process,with different process parameters,was analyzed.In addition,we investigated the regular change of abrasive concentration effect on copper and tantalum removal rate and within wafer non-uniformity(WIWNU) in CMP process.When the abrasive concentration is 3 wt%,in bulk elimination process,the copper removal rate achieves 6125 °/min,while WIWNU is 3.5%,simultaneously.In residual copper elimination process,the copper removal rate is approximately 2700°/min,while WIWNU is 2.8%.Nevertheless,the tantalum removal rate is 0 °/min,which indicates that barrier layer isn’t eliminated in residual copper elimination process.The planarization experimental results show that an excellent planarization performance is obtained with a relatively high copper removal rate in bulk elimination process.Meanwhile,after residual copper elimination process,the dishing value increased inconspicuously,in a controllable range,and the wafer surface roughness is only 0.326 nm(sq < 1 nm) after polishing.By comparison,the planarization performance and surface quality of alkaline slurry show almost no major differences with two kinds of commercial acid slurries after polishing.All experimental results are conducive to research and improvement of alkaline slurry in the future.     

CMP透明膜厚测量设备发展历程

论述了反射光谱学及椭圆偏振法的原理,根据这些原理分析了离线测量设备,并列举了具有代表性的设备Nanospec6100和KLA-TENCOR的ASET-F5X,指出离线设备的特点及其局限性;分析了集成测量平台的特点,相比于离线测量,集成测量平台可获得较高的片间非均匀性．但会造成前5～7片的浪费,列举代表性集成平台NovaScan 2040,并分析其具体的技术特点：分析了在线传感器终点检测的优越性,其具有控制薄膜形貌及终点检测的功能,结合先进过程控制,可以达到极高的平整度;结合以上分析,指出今后CMP设备的发展方向。     

优化CMP碱性铜抛光液配比的新方法

采用响应曲面法(RSM)和人工神经网络(ANN)分别对化学机械抛光(CMP)碱性铜抛光液的主要成分(SiO2磨料、FA/O型螯合剂、H2O2氧化剂)进行优化研究.采用RSM优化,当抛光液中磨料、氧化剂和FA/O型螯合剂的体积分数分别为10.57％,1.52％和2.196％时,Cu的抛光速率的预测值和实测值分别为924.29和908.96 nm/min;采用ANN结合人工蜂群算法(ABC)优化,当抛光液中磨料、氧化剂和FA/O型螯合剂的体积分数分别为11.58％,1.467％和2.313％时,Cu的抛光速率的预测值和实测值分别为947.58和943.67 nm/min,其拟合度为99.36％,高于RSM的94.63％,且均方根误差较低为0.199 3.结果表明,在抛光液配比优化方面,RSM和ANN都是可行的,但后者比前者具有更好的拟合度和预测准确度,为更加高效科学地优化抛光液配比提供了一种新的思路和方法.     

超大规模集成电路激光束加工技术的新进展

本文给出了近十年来各种波长的激光在超大规模集成电路(VLSI)的精细化加工中的应用领域,重点介绍了激光在VLSI制备中应用的新进展。包括激光金属平坦化,激光载带自动键合,激光多层布线和多芯片互连以及激光掩膜版和芯片图形缺陷的修复。     

一种新的隔离结构表面平坦化技术

为克服目前隔离结构平坦化技术在工艺控制、平坦化质量等方面存在的问题,提出了一种新的隔离结构表面平坦化工艺,即利用稠光刻胶做掩膜,结合反应离子刻蚀技术与湿法腐蚀技术,实现不同厚度隔离结构的平坦化.结果表明隔离结构边缘陡峭,硅表面平坦均匀.     

Ozone/organic-source APCVD for conformai doped oxide films

Borophosphosilicate glass (BPSG) films were deposited with a new chemical vapor deposition method using ozone and organic sources under atmospheric pressure condition at 400° C called ozone/TEOS APCVD. Trimethylborate (TMB:B(OCH₃)₃) and trimethylphosphate (TMP:PO(OCH₃)₃) were utilized to dope phosphorus and boron into deposited films. Boron and phosphorus concentration in the films are easily controlled at up to 15 mole%. Conformality and reflow characteristics for the BPSG film are superior to those for BPSG film deposited by the SiH₄ + PH₃ + B₂H₆ + O₂ CVD method. Planarization of underlying patterns, which have half-micron spaces with high aspect ratio, was successfully accomplished.     

Cu CMP过程中背压对膜厚一致性影响

在极大规模集成电路Cu布线的化学机械平坦化过程中,抛光后表面薄膜厚度的一致性是检验平坦化能力的重要参数。从抛光过程中晶圆所受背压方面着手,研究了在不同背压参数情况下抛光后表面薄膜的一致性,得出了在工作压力为103 mdaN/cm2(1 kPa=10 mdaN/cm2)时,最佳的背压参数为108 mdaN/cm2。采用此工艺参数进行抛光后得到的晶圆表面薄膜非均匀性为5.04%,即一致性可以达到94.96%,而且此时表面粗糙度为0.209 nm,从而得到了良好的抛光效果,为极大规模集成电路Cu布线化学机械平坦化的进一步发展提供了新的途径。