Effect of fluorine contamination on barrier metal oxidation

We clarified that interfacial barrier metal oxidation with inter layer dielectric (ILD) could be revealed by X-ray photoelectron spectroscopy (XPS) on the peeled-side of the barrier metal, and the barrier metal oxidation was promoted by fluorine contamination which adsorb to the ILD surface during etching. To consider the effect of fluorine contamination on barrier metal oxidation, hydrolysable property of fluorine contamination was evaluated by measuring the change of F 1s spectrum after dipping in boiling water. Moreover, fluoride ions and the acidity of water in which fluorine contamination was dipped were measured by Ion chromatography and pH measurement, respectively. According to our experiments, it was suggested that hydrofluoric acid (HF) acted as an oxidizing catalyst to promote barrier metal oxidation at the interface of barrier metal and ILD.     

New solutions for intermetal dielectrics using trimethylsilane-based PECVD processes

Trimethylsilane, (CH₃)₃SiH, is a non-pyrophoric organosilicon gas. This material is easily used to deposit dielectric thin films in standard PECVD systems designed for SiH₄. In addition to deposition of standard dielectrics (e.g. SiO₂), trimethylsilane can be used to deposit reduced permittivity (low-k) dielectric versions of amorphous hydrogenated silicon carbide and its oxides. The low-k carbides (k<5.5) are highly insulating and useful as hard masks, etch stops and copper diffusion barriers. The low-k oxides (2.6<k<3.0) are useful as intermetal dielectrics, and exhibit stability and electrical properties which can meet many specifications in device fabrication that are now placed on SiO₂. This paper reviews PECVD processing using trimethylsilane. Examples will show that the 3MS-based dielectrics can be used in place of SiH₄-based oxides and nitrides in advanced device multilevel metal interconnection schemes to provide improved circuit performance.     

体硅CMOS射频集成电路中高Q值在片集成电感的实现

制作高Q值在片集成电感一直是体硅CMOS射频集成电路工艺中的一大难点，文章讨论和分析了体硅RF IC工艺中提高在片集成电感Q值的几种常用方法，这些方法都与CMOS工艺兼容。     

Thermal conductivity of ultra low-k dielectrics

The so-called 3ω measurement technique (transient hot wire method) was established to determine the thermal conductivity of thin films. Measurements of standard substrates and films validate the found thermal conductivity values and agree with published, commonly accepted values. The method was successfully applied to determine the thermal conductivity of porous low-k dielectric materials using special test structure fabrication. The thermal conductivity of the porous low-k dielectrics thus measured is only between 7 and 13% of the thermal conductivity of thermally grown silicon dioxide.     

用于新一代器件的最新STI和金属CMP浆料

现已开发出了用于浅沟道隔离穴STI雪、铜CMP和低k介质的新型材料。90nm以及下一代技术节点的新型器件要求在软接触CMP条件下减少缺陷率,改善片子表面形貌的衰减。获得的新材料展示了在CMP性能和街写特性方面的改进,因此这些材料被认为能够适应未来技术要求。这些材料的关键之处在于大颗粒尺寸的控制,进行平面化和金属抛光的化学控制以及将控制方法用于旋涂玻璃()材料。     

High density large area hydrogen plasma by hollow cathode plasma array

Hydrogen plasma becomes an alternative to the conventional oxygen plasma in stripping photoresist in the next generation semiconductor processing because the conventional oxygen plasma is known to degrade ultralow dielectric constant films by depleting carbons from the films. An array of hollow cathode plasma is designed to have uniform and high density hydrogen plasma. From many combinations of cavity size and distribution, it is found that cylindrical ceramic cavity with 6 mm inner diameter, 10 mm depth and 30 mm spacing between neighboring cavities shows the widest process window. Nineteen cavities are engraved into the cathode plate of 200 mm diameter. Ceramic cavities are needed to survive against energetic ion bombardment. Dependence of the stripping rate on mixture ratio of N₂/H₂, gas flow rate, chamber pressure and RF power is investigated, and we have found that a stripping rate of more than 260 nm/min with 7% uniformity can be achieved when chamber pressure is 213 Pa, gas flow rate 10000 sccm, N₂/H₂ mixture ratio of 3:7 and RF power 2.5 KW. This high density hydrogen plasma in the order of 10¹¹/cm³can be a very effective method of photoresist stripping in the dual damascene process of copper metal and low-k dielectrics where oxygen plasma cannot be used.     

Influence of low-k dry etch chemistries on the properties of copper and a Ta-based diffusion barrier

In this study, the film properties of Cu and a Ta-based diffusion barrier deposited on organic polymer and SSQ-based low-k materials with subtractive porosity were investigated. Emphasis was put on the effects of exposure of the low-k materials to the dry etch plasmas prior to metal deposition. The metal film properties were influenced by the type of the dry etch plasma chemistry used and by the porosity of the low-k material. Thermal desorption spectra (TDS) obtained during annealing of these metal films revealed an increased amount of species with m/e 44, attributed to CO₂, and H₂O desorbing from the Cu film at high temperatures. The TDS data for the Ta film did not contain such high temperature desorption peaks for these species mentioned. Surface morphology of the Cu and Ta films observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) also showed a poor wetting of the metal films on the porous low-k materials that have been dry etch plasma treated.     

Material modification of the patterned wafer during dry etching and strip determined by XPS

XPS analysis on single damascene (SD) patterned wafers was performed to study the modification of materials, especially the sidewall, during etching and strip. LKD-5109, MSQ-type materials (k≈2.2) were used as ILD, SiC/SiO₂ as top hard mask (HM), and SiC as bottom liner. The etching in Ar/CF₄/CH₂F₂/O₂ creates a CF_x polymer passivation layer on all patterned surfaces. The etched sidewall surface consists of two regions; a thin skin layer of CF_x polymer and CF-rich SiOC layer behind. An N₂/O₂ strip removes CF_x polymer and CF-rich layer efficiently (less than 1 at.% fluorine content). Instead of fluorine, CN-rich layers containing 11–20 at.% nitrogen were observed for all surfaces. After N₂/O₂ strip, the sidewall consists of two regions; a few nanometers of CN rich SiOC layer at the surface and several tens of nanometers of a C-depleted oxide type layer. N₂/H₂ strip provides a thinner C-depleting oxide type layer than either N₂/O₂ and CF₄/O₂ strips. However, the N₂/H₂ strip cannot eliminate fluorine contamination more than the N₂/O₂ strip.     

在ICE设备上进行低材料灰化技术(英文)

为满足半导体产品的高性能化,Low-k穴低导电雪材料正被使用于层间绝缘膜,但是Low-k材料在灰化穴Ashing雪过程中由于高温及氧自由基穴O-radical雪的作用而引起材质变化导致导电率上升的问题的发生。为解决这个问题,在ICE设备上开发了灰化Low-k周边的低温处理工艺。Low-k导电率变化系在Low-k表面生成高导电率氧化层所致,所以为减少导电率变化须选择合适的离子源生成尽可能薄的氧化层是非常重要的且已被证明。在这里,Low-k灰化时导电率变化的机理,改善效果及相关运用作个介绍。     

微水导激光划片工艺原理及应用

从应用需求出发,介绍了微水导激光划片工艺的主要原理和特点;对其关键工艺机构中的光学聚焦系统、激光在水柱中的全反射传播、激光系统、压力水腔和喷嘴组成的光液耦合器等原理进行了简单分析和介绍;对微水导激光划片工艺的应用前景进行了总结和展望。