About target binding
First, what is the target binding? The scope and process of target binding?
Binding refers to soldering a target to a back target with solder. There are three main ways: crimping, brazing and conductive adhesives.
1. Crimp: The use of beading, generally in order to improve the goodness of contact, will increase graphite paper, Pb or In leather;
2. Brazing: In the case of generally using solder, the sputtering power is required to be less than 20W/cm2, and the solder is commonly used in In, Sn, and In-Sn; our company uses indium welding bonding technology.
3. Conductive adhesive: The conductive adhesive used should be resistant to high temperature and the thickness is 0.02-0.05um.
Second, the scope of application of the binding
Technically, the target surface can be metallized. The target can be bonded with a copper back target by our indium solder bonding technology to improve the heat dissipation of the sputtering process and improve the utilization of the target.
Recommended binding targets:
ITO, SiO2, ceramic brittle target and sintered target;
Soft metal targets such as tin and indium;
The target is too thin, the target is too expensive, and the like.
However, the following situations have drawbacks:
1. Targets with low melting points, such as indium, selenium, etc., may become soft and deformed when metallized;
2. Precious metal targets, one is the actual weight is easy to disagree, the second is metallization and untie when there will be wasted material, it is recommended to pad a piece of copper.
Third, the choice of back target
Material requirements: generally use oxygen-free copper and molybdenum targets, thickness is about 3mm
Good electrical conductivity: commonly used oxygen-free copper, the thermal conductivity of oxygen-free copper is better than copper;
Strong enough: too thin, easy to deform, not easy to vacuum seal.
Structural requirements: hollow or solid structure;
Moderate thickness: about 3mm, too thick, consumes part of the magnetic strength; too thin, easy to deform.
Fourth, the process of indium welding binding
1. Pre-binding target and back surface pretreatment
2. Place the target and the backing plate on the brazing table and heat up to the bonding temperature.
3. Do target and backplane metallization
4. Bonding target and backing plate
5. Adjust the bonding position
6. Cooling and post-processing
Indium welding has a melting temperature of 160° or more