Paper PS-TuP7
Inductively Coupled Plasma Reactive Ion Etching of Copper Thin Film using Organic Chemicals and Alcohols

Tuesday, October 22, 2019, 6:30 pm, Room Union Station B

To improve the performance of Semiconductor memory device, it is important to reduce RC delay. Copper is widely used as interconnect material because it has lower resistivity and higher electromigration resistance than aluminum. However, the conventional dry etching of copper is very difficult due to low vapor pressures of copper compounds and/or low reactivity of copper . As an alternative to dry etching for copper interconnect, a damascene process has been developed in the early 1990s and has been used until now. However, as the device critical dimension continues to shrink, especially below about tens of nanometers, the resistance of the device increases and the performance of the device is deteriorated. As a result, the development of a conventional dry etch process is inevitable.

In this study, new copper etching process which utilizes organic chemicals and alcohols are studied. The etch characteristics of copper under these gases are investigated using inductively coupled plasma reactive ion etching (ICPRIE) as a function of gas concentration and the effects of main etch parameters such as ICP power, dc-bias voltage to substrate, and process pressure are also examined. The etch profiles are observed using FESEM and the etch products formed during etching are analyzed using X-ray photoelectron spectroscopy (XPS), Energy dispersive X-ray spectroscopy (EDS) is also carried out to indentify the etch residues. Plasma characteristics are analyzed using optical emission spectroscopy (OES) and Langmuir probes.