Cost-effective equipment for surface pre-treatment for cleaning and excitation of substrates in semiconductor technology

This article presents a cost-effective ultraviolet-ozone cleaner (UV/O 3 Cleaner) for surface pre-treatment of substrates in the field of semiconductor technology. The cleaner consists of two chambers, the upper one contains the electronics, including the time counter. The lower chamber contains the two UV sterilisation lamps and a UV reflector of anodized aluminium, which confines the area of high Ozone concentration in the area of interest. The device is successfully used for surface cleaning and modification of different materials. To this end, the two important wavelengths 253.7 nm (excitation of organic residues) and 184.9 nm (production of ozone from the atmospheric environment as a strong oxidant) were first detected. The effectiveness of UV/O 3 cleaning is demonstrated by improving the properties of indium tin oxide (ITO) for OLED fabrication. The contact angle of water to ITO could be reduced from 90° to 3° and for diiodomethane, it was reduced from 55° to 31° within the 10 min of irradiation. This greatly improved wettability for polar and non-polar liquids can increase the flexibility in further process control. In addition, an improvement in wettability is characterized by measuring the contact angles for titanium dioxide (TiO 2 ) and polydimethylsiloxane (PDMS). The contact angle of water to TiO 2 decreased from 70° to 10°, and that of diiodomethane to TiO 2 from 54° to 31°. The wettability of PDMS was also greatly increased. Here, the contact angle of water was reduced from 109° to 24° and the contact angle to diiodomethane from 89° to 49°. Article Highlights We report a cost-effective dry-cleaning device for surface cleaning and modification based on ultraviolet-ozone irradiation. Contact angle measurements show an increase of wettability for different materials due to surface modification. The UVO3 pre-treatment improves layer formation and optoelectrical properties of OLEDs.