Advanced ULSI multilevel metallization using non-steady state by Flow Modulation technique

采用非稳态流量调制技术的先进 ULSI 多层金属化

• 批准号: 11450269
• 负责人: SHIMOGAKI Yukihiro
• 金额: $ 7.74万
• 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 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450269/
• 关键词: CVD; Barrier Metal; Sequential Process; Nucleation; Thin Film Growth; Crystallization; Impurity Control; Resistivity; CDV

The device integration requires narrow wiring technique which results in high resistivity. This will lead to employ multilevel metallization scheme, in which the width of conductive metal line keeps the same level. Thus, the number of metal line layers now exceeds 8 and it will go up to 12, in the near future. The so-called back end process to fabricate multilevel metal layers became the dominant process for ULSI process. These structures require CVD process to form metal lines, because it has superior step coverage profile in high aspect ratio trenches/holes. The ultra thin films with a thickness of less than 10nm are also important, because of the small dimension of the ULSI devices. However, the integration of novel material will suppress the formation of continuous thin layers due to the nucleation issues.The normal CVD employed steady process conditions, such as gas flow rate, temperature, and pressure. If we introduce sequential change of these parameters, it will enhance the ads … More orption and desorption of the precursor. That may contribute to control the initial step of thin film growth. When we started this research project, there were not so much related research, but recently ALD (Atomic Layer Deposition) process was proposed to improve ULSI device fabrication. Those methods are using sequential flow of source precursors. For example, in our study, TiN deposition from TiCl_4/NH_3 chemistry was investigated. NH_3 was supplied to the reactor all the time of deposition. TiCl_4 supply was switched on/off to make TiN deposition with NH_3 or just to make reduction by NH_3. The step coverage of TiN films from TiCl_4/NH_3 becomes excellent when the concentration of TiCl_4 becomes high. The reason for this behavior can be explained by following mechanisms. When the TiCl_4 concentration is high, the growth rate becomes independent of TiCl_4 concentration due to saturated surface adsorbates. This is an ideal situation for uniform step coverage, however, the high concentration of surface adsorbates turns into high residual chlorine concentration. Thus the FMCVD sequence is proposed. The deposition will be made with high TiCl_4 concentration range to realize excellent step coverage. In the next step, only NH_3 will be supplied to reactor to make chlorine reduction. We have proved that FMCVD sequence can realize the excellent step coverage and low resistivity at the same time. We also worked on how the residual chlorine is removed from TiN film using TDS, TEM amd EDX. The results clearly showed that residual chlorine mainly exists in the grain boundaries of TiN poly crystals. The FMCVD with many cycle times also contributed to remove chlorine which was incorporated in TiN grain. These investigations contributed to design the optimum process conditions for FMCVD and ALD. Less

器件集成需要较窄的布线技术，这导致了高电阻率。这将导致采用多层金属化方案，其中导电金属线的宽度保持相同的水平。因此，金属线层的数量现在超过8层，在不久的将来将增加到12层。制造多层金属层的所谓后端工艺成为ULSI工艺的主导工艺。这些结构需要CVD工艺来形成金属线，因为它在大长宽比沟槽/孔洞中具有优越的台阶覆盖轮廓。由于ULSI器件的尺寸较小，厚度小于10 nm的超薄膜也很重要。然而，由于形核问题，新材料的集成将抑制连续薄层的形成。正常的CVD采用稳定的工艺条件，如气体流量、温度和压力。如果我们引入这些参数的顺序变化，它将增强ADS…前体的更多吸附和解吸。这可能有助于控制薄膜生长的初始步骤。当我们开始这项研究项目时，还没有太多的相关研究，但最近提出了ALD(原子层沉积)工艺来改进ULSI器件的制造。这些方法使用的是源前体流的顺序。例如，在我们的研究中，我们研究了TiCl4/NH3化学中TiN的沉积。在整个沉积过程中，NH3一直被提供给反应器。TiCl4的通断可使TiCl4与NH3一起沉积TiN或仅用NH3还原TiN。TiCl4/NH3的TiC膜在TiCl4浓度较高时，TiN膜的阶跃覆盖率较高。这种行为的原因可以通过以下机制来解释。当TiCl4浓度较高时，由于饱和表面吸附，生长速率与TiCl4浓度无关。这是均匀阶梯覆盖的理想情况，然而，表面吸附的高浓度会导致高剩余氯浓度。因此，提出了FMCVD序列。在较高的TiCl4浓度范围内进行沉积，以实现良好的阶跃覆盖。在下一步，将只向反应器提供NH3进行氯气还原。证明了FMCVD序列可以同时实现良好的阶跃覆盖和低阻率。我们还研究了如何利用TDS、TEM和EDX去除TiN膜中的余氯。结果表明，余氯主要存在于TiN多晶的晶界中。循环次数多的快速化学气相沉积也有助于去除TiN颗粒中的氯。这些研究有助于设计FMCVD和ALD的最佳工艺条件。较少

项目成果

H.Hamamura, R.Yamamoto, K.Takahiro, S.Yamaguchi, H.Komiyama, Y.Shimogaki: "FMCD(Flow Modulation Chemical Vapor Deposition) for reducing residual chlorine concentration in TiN films"Proc. Advanced Metallization Conference in 1998. 345-349 (1999)

H.Hamamura、R.Yamamoto、K.Takahiro、S.Yamaguchi、H.Komiyama、Y.Shimogaki：“用于降低 TiN 薄膜中残留氯浓度的 FMCD（流量调节化学气相沉积）”Proc。

H.Hamamura, R.Yamamoto, H.Komiyama, Y.Shimogaki: "Low resistivity TiN films at low deposition temperature using flow modulation chemical vapor deposition (FMCVD)"Proc. Advanced Metallization Conference in 1999. 283-287 (2000)

H.Hamamura、R.Yamamoto、H.Komiyama、Y.Shimogaki：“使用流量调制化学气相沉积 (FMCVD) 在低沉积温度下形成低电阻率 TiN 薄膜”Proc。

H. Hamamura, R. Yamamoto, K. Takahiro, S. Yamaguchi, H. Komiyama, and Y. Shimogaki: "FMCVD (Flow Modulation Chemical Vapor Deposition) for reducing residual chlorine concentration in TiN films"Proc. Advanced Metallization Conference. 345-349 (1999)

H. Hamamura、R. Yamamoto、K. Takahiro、S. Yamaguchi、H. Komiyama 和 Y. Shimogaki：“用于降低 TiN 薄膜中残留氯浓度的 FMCVD（流量调节化学气相沉积）”Proc。

H. Hamamura, R. Yamamoto, H. Komiyama, and Y. Shimogaki: "Low resistivity TiN films at low deposition temperature using flow modulation chemical vapor deposition (FMCVD)"Proc. Advanced Metallization Conference. 283-287 (2000)

H. Hamamura、R. Yamamoto、H. Komiyama 和 Y. Shimogaki：“使用流量调制化学气相沉积 (FMCVD) 在低沉积温度下形成低电阻率 TiN 薄膜”Proc。

H.Hamamura,R.Yamamoto,K.Takahiro,S.Yamaguchi,H.Komiyama,and Y.Shimogaki: "FMCVD (Flow Modulation Chemical Vapor Deposition) for reducing residual chlorine concentration in TiN films"Proc.Advanced Metallization Conference in 1998. 345-349 (1999)

H.Hamamura、R.Yamamoto、K.Takahiro、S.Yamaguchi、H.Komiyama 和 Y.Shimogaki：“FMCVD（流量调节化学气相沉积）用于降低 TiN 薄膜中的残余氯浓度”Proc.1998 年高级金属化会议