Study on low damage engraving of ultra-fine/high aspect ratio hole for ULSI process

ULSI工艺超细/高深宽比孔低损伤雕刻研究

基本信息

批准号：
11555179
负责人：
HORIIKE Yasuhiro
金额：
$ 8.9万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

This study was carried out by the purpose that SiO2 contact hole in the ULSI device process was engraved satisfying high aspect ratio, low damage and good reproducibility. The study consists of ultra-high voltage TEM observation of contact holes, interaction between fluorocabon plasmas and an inner wall of a reactor and a sidewall protection etching. At first, bottoms of 0.1μm diameter holes engraved by the magnetron RIE employing were observed by a cross sectional TEM. The spot-like defects were observed, while these defects were annealed out at 500℃. This shows that serious defects are not induced so much. However, it is reported that actual contact resistance for the as-etched bottom surface is increased. This implies requirement of further efforts to improve the defects reduction. Next, to study the wall interaction of fluorocarbon species in C_4F_8 ICP (inductively coupled plasma), an ICP reactor equipped with a small scaled QMS, OES and a temperature controlled metal stage was de … More veloped and dependences of stage temperature, distance from the stage, bias voltage added to the stage and residence time on densities of fluorocarbon species near the stage surface. As a result, total densities of CF_x(x=l-3) radicals increased at any distance with increasing stage temperature. This increase was larger as the gap was closer to the stage surface and especially CF_3 radicals indicated the most increase. In addition, Variations of radical densities with change in temperatures could be suppressed by shorter residence time. Finally, we studied a new method achieving high aspect ratio feature by protection of the mask side wall erosion during etching. For the goal, we preserved the resist mask feature by deposition of species on the resist side wall at a glancing angle. As a result, reduction of the mask thickness and expansion of the opening width could be minimized, thus engraving holes with 0.15μm diameter and 15 of aspect ratio successfully. The method was applied to etching of ultra-high aspect ratio Si trench by improving the Bosch method. To transfer the result to fabricate a bio chip, the Si surface was oxidized and an electroosmosis pump was developed. Furthermore, a new "Flow-FET" was fabricated by forming a Au electrode on the back side of the Si substrate. Consequently, positive and negative Zeta potentials were controlled freely by adding 0 and 5 volts to the electrode. Less

本研究的目的是在ULSI器件工艺中雕刻SiO2接触孔，满足高深宽比、低损伤和良好的再现性。研究内容包括接触孔的超高压TEM观察、氟碳等离子体与荧光粉之间的相互作用。首先，通过截面TEM观察采用磁控管RIE雕刻的0.1μm直径孔的底部。观察到点状缺陷，而这些缺陷在 500℃ 下退火，这表明没有产生太多严重缺陷，但据报道，蚀刻后的底面的实际接触电阻增加了。接下来，为了研究碳氟化合物在 C_4F_8 ICP（感应耦合等离子体）中的壁相互作用，配备了小型 QMS、OES 和温控金属台的 ICP 反应器。开发了工作台温度、距工作台的距离、添加到工作台的偏置电压和停留时间对工作台表面附近的碳氟化合物物质的密度的依赖性，结果是 CF_x(x=l-3) 自由基的总密度。随着平台温度的升高，在任何距离处，这种增加都越大，特别是CF_3自由基表明，随着温度的变化，自由基密度的变化最大。最后，我们研究了一种通过在蚀刻过程中保护掩模侧壁腐蚀来实现高深宽比特征的新方法，我们通过在抗蚀剂侧壁上沉积物质来保留抗蚀剂掩模特征。结果，可以最大限度地减少掩模厚度和开口宽度的扩大，从而成功地雕刻出直径为0.15μm、深宽比为15的孔。硅沟槽由为了将结果转化为生物芯片，我们对硅表面进行了氧化，并开发了电渗泵。此外，通过在硅背面形成金电极，制造了一种新的“Flow-FET”。测试时，通过向电极添加 0 和 5 伏电压来自由控制正和负 Zeta 电位。