Development Trend of ITO Sputtering Target

In recent years, with the development of large-scale flat-panel displays, the requirements of ITO target size and density are higher and higher, and hot pressing equipment and technology are far from meeting their requirements. Therefore, large-scale and high-density ITO targets by sintering process have become the focus of research and development of major target manufacturers in China. After a long time of development, the quality and cost of LCD products have been improved, and the requirements for ITO target materials have been improved.

 

At present, LCD, PDP, OLED and other display technologies require the improvement of ITO target quality and cost reduction, so ITO target presents the following development trend.

1) Large size

With the continuous development of light and low price of liquid crystal module products, the corresponding ITO glass substrate also has a noticeable large-scale trend, so the large-scale ITO target single-chip size is inevitable. To meet large-area coating's technological requirements, advanced technology enterprises adopt large-scale targets to reduce the number of splicing joints of targets and improve efficiency and quality. This is mainly because the gap between the targets destroys the directional movement of the electrons on the target surface, and it is easy to gather a large number of charges in the gap, which is easy to cause the discharge phenomenon of the target, resulting in the early blackening of the target. The blackening of the target may cause many problems, such as the increase of surface resistance, the rise in the film thickness, the decrease of the transmittance, the decrease of the sputtering rate, and the conductive increase powder and the increase of the voltage.

 

2) Low resistivity

With the development trend of LCD's more and more refinement and its different drivers, a transparent conductive film with smaller resistivity is needed. ITO target performance is required to be improved, sputtering technology and equipment are needed to be improved. At present, the ITO film resistance formed by the ITO target has reached below 1.1 × 10-4 Ω· cm at the base temperature of 350 ℃, while the ITO film for high-end LCD requires lower resistance.

3) High density

As the most important technical index of ITO target, density directly affects the use efficiency of the target and the quality of ITO film. If a low-density target is used, the effective sputtering area will be reduced. The sputtering speed will also be reduced, the use cycle of the target will be shortened, resulting in an increase of cost and the decline of ITO film quality. If a high-density target is used, the surface change will be small, the film quality will be high, and the use cycle will be extended.

 

4) Target body integration

As mentioned before, the target material develop towards a large area. In the past, when the technical capacity was insufficient, multiple targets must be used to weld into a large area. However, due to the degradation of coating quality caused by the joint, most of the targets are formed as a whole to improve the coating quality and utilization rate. The increasing size of new generation LCD glass substrate is a severe challenge to target manufacturers in the future.

5) Increase usage

Improving the sputtering efficiency of the ITO target has been one of the hot and challenging issues in this field. The planar ITO sputtering target's efficiency is about 20-25%, while the efficiency of the non-planar ITO sputtering target can be increased to 40%～60%. At present, target manufacturers are actively researching and developing rotary ITO target and tubular ITO target. The research and application of this technology are bound to bring new technological innovations to the ITO industry.