Technology briefing

ITO conductive film has good conductivity, and has extremely high visible light transmittance and infrared reflectivity. ITO film has a wide range of applications, and is an indispensable material for making transparent electrodes in electronic systems such as flat-panel displays, solar cells, and photoelectric detectors. In recent years, smartphones have become more and more popular, and ITO has been used to make touch module, which have a great demand from consumer market. In addition, ITO film can also be used to make transparent heating elements, for example, the anti-static films, electromagnetic wave protective films and other materials used in photo-electronic devices. Due to its spectral absorption and reflection characteristics, it also can be used to make optical and energy-saving films. ITO transparent conductive film can be deposited on glass or flexible polymer film such as PC and PET substrate, etc. Recently, due to the tremendous requirements of light weight, small size photoelectric modules and systems, many applications tend to use ITO film on PET and COP substrate. It has the advantages of light weight, thinness, impact resistance, as well as flexibility to fulfill the production trend either in present and near future market. However, since the properties and rigidity of the polymer substrate are not as good as glass, so there is more technically challenging to deposit an ITO material on a flexible polymer substrate. The cross-sectional structure of the film layers of the ITO film is shown in Figure 1, and Figure 2 is the ITO film in roll type.

Basically, the fabrication of a flexible ITO film needs to employ roll-to-roll sputtering process. The roll-to-roll sputtering process is more difficult than that of a in-line sputtering process. In addition to employ expensive and precision equipment, the roll-to-roll coating process is also difficult to handle. A DC(direct current) /MF(medium frequency alternating current) commonly used as the sputtering sources for ITO vacuum deposition. The deposition of metal-oxide on a flexible substrate inside a vacuum space need to control the processes' conditions precisely, without spoil the specification of the film quality. It is harder than the deposition on a glass substrate. Therefore, the ITO sputtering process is a technology-intensive process that need to be operated by a technical team with professional expertise.

Efun's team is with practical experience in the roll-to-roll sputtering technologies, and also accumulated tremendous skills of the coating equipment design, production, automatic control, process development, and optical film layer simulation design. Therefore, Efun can provide best customized services to provide best ITO products to satisfy the demand from our customers.

Sales window：Ryan Zheng  ( 0937-779-612  ); Email: ryan671012 @efun.com.tw