Chou Yu-Wei, Chang Shou-Yi, Keng Pei Yuin
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
ACS Omega. 2023 Oct 13;8(42):39699-39708. doi: 10.1021/acsomega.3c05629. eCollection 2023 Oct 24.
In this study, we investigated the thermal stabilities of butylphosphonic acid (BPA) and aminopropyltriethoxysilane (APTES) self-assembled monolayers (SAM) on a Si substrate. The thermal desorption and the thermal cleavage of the BPA and APTES SAM film on the Si substrate were studied by X-ray photoelectron spectroscopy (XPS) upon thermal treatment from 50 to 550 °C. XPS analyses show that the onset of the thermal desorption of the APTES monolayer occurs at 250 °C and the APTES SAM completely decomposed at 400 °C. Conversely, BPA SAM on Si shows that the onset of thermal desorption occurs at 350 °C, and the BPA SAM completely desorbed at approximately 500 °C. Our study revealed that the organophosphonate SAM is a more stable SAM in modifying the dielectric sidewalls of a Cu interconnect when compared to organosilane SAM. To overcome the spontaneous reaction of the organophosphonate film on the metal substrate, a simple orthogonal functionalization method using thiolate SAM as a sacrificial layer was also demonstrated in this study.
在本研究中，我们研究了丁基膦酸（BPA）和氨丙基三乙氧基硅烷（APTES）在硅衬底上自组装单分子层（SAM）的热稳定性。通过X射线光电子能谱（XPS）研究了硅衬底上BPA和APTES SAM膜在50至550°C热处理后的热脱附和热裂解情况。XPS分析表明，APTES单分子层的热脱附起始温度为250°C，APTES SAM在400°C时完全分解。相反，硅上的BPA SAM显示热脱附起始温度为350°C，BPA SAM在约500°C时完全脱附。我们的研究表明，与有机硅烷SAM相比，有机膦酸盐SAM在修饰铜互连的介电侧壁时是一种更稳定的SAM。为了克服有机膦酸盐膜在金属衬底上的自发反应，本研究还展示了一种使用硫醇盐SAM作为牺牲层的简单正交功能化方法。
