The COG assembly process of LCD is to mount the bare IC onto the ITO glass and use the compression and deformation of the gold ball to make the pins on the ITO glass conductive with the pins on the IC. Due to the continuous development of fine line technology, it has been developed to produce products with Pitch of 20μm and line of 10μm. The production and assembly of these fine line electronic products, the surface cleanliness of the ITO glass is very high, requiring good solderability, solid welding, and no organic and inorganic substances left on the ITO glass to prevent the conductivity of the ITO electrode terminals and IC BUMP, therefore, the cleaning of the ITO glass is very important. In the current ITO glass cleaning process, everyone is trying to use various cleaning agents (alcohol cleaning, cotton swab + lemon water cleaning, ultrasonic cleaning) for cleaning, but the introduction of cleaning agents will lead to other related problems due to the introduction of cleaning agents, so the exploration of new cleaning methods become the direction of the efforts of manufacturers. Through gradual experiments, the use of the principle of plasma cleaning to clean the surface of ITO glass is a more effective cleaning method.

In the plasma cleaning of liquid crystal glass, the activation gas used is the plasma of oxygen, which can remove oily dirt and organic pollutant particles because the oxygen plasma can oxidize the organic matter and form a gas to discharge. Its only problem is the need to include a de-static device after the removal of particles, and its cleaning process is as follows:

Blowing - Oxygen Plasma - De-static

The cleanliness and bonding of LCD and its electrode terminal ITO are greatly improved after the dry cleaning process.

LCM LCD module, the current trend of assembly technology is mainly SIP, BGA, CSP packaging to make semiconductor devices to modular, highly integrated and miniaturized direction. In such packaging and assembly process, the biggest problem is the organic contamination at the bonding filler and the formation of oxide film in the electric heating. Due to the presence of contaminants on the bonding surface, the bonding strength of these components is reduced and the potting strength of the resin after encapsulation is reduced, which directly affects the level of assembly and continued development of these components. In order to increase and improve the assembly ability of these components, everyone is trying to do everything possible to deal with them. Improving practice has proven that the appropriate introduction of plasma cleaning technology in the packaging process for surface treatment can greatly improve the reliability of the package and improve the yield.

In the COG process of mounting bare chip IC on glass substrate LCD, when the chip is bonded and then hardened at high temperature, there is a situation where the substrate plating becomes analyzed out on the surface of the bonding filler. In addition, the bonding filler is sometimes contaminated by the spillage of the bonding agent such as Ag slurry. If these contaminants can be removed by plasma cleaning before the hot-press bonding process, the quality of hot-press bonding can be greatly improved. In addition, since the wettability of both the substrate and the bare chip IC surface is improved, the bonding tightness of the LCD-COG module can be improved, and the line corrosion problem can be reduced.