Views:29 Author:Site Editor Publish Time: 2017-10-23 Origin:Site
A backing plate is often made by copper or molybdenum (lower thermal expansion coefficient). Backing plates play an important role in PVD industry and have been a popular parts for a lot of sputtering target set. As a professional China sputtering target manufacturer, Baoji Oukai Sputtering Target summarizes the reasons of bonding backing plate in a sputtering target.
Sputtering generate a quite large amount of heat and the temperature could increase a lot for the sputter target. If the temperature goes too high, it is possible to break the ceramic material or simply melt the metal targets with low melting point. Thus, it is very important to cool down the target. A bonded metal backing could be used as cooler and it is a lot easier to be mounted to the water cooling system.
In a lot of cases, the sputter target itself is an electric insulator. To enhance the conductivity between the sputtering target and electrode, a backing plate is bonded. Usually, indium is used as the bonding agent to connect sputter target material with the backing plate. As In melt at a very low temperature, the process is usually safe for the target material.
For ceramic sputtering targets, such as carbides, nitrides, fluorides and some alloy, the material is quite fragile and it will be a disaster if the equipment require screw or bolts to mount the target on without a backing plate. Because drill holes on these kind of material is not only hard but also highly possible to break the target.
On the other hand, a large backing plate that holds a few pieces of relatively small sputtering target together could form a large sputtering target, which could be used in coating a very large substrate, such as the LCD panel.
Also, it is possible that the target material is extremely expensive and soft, such as gold. A backing plate is frequently used to obtain a convenient thickness and strength without cost too much on the material.
Now, do you know the reasons why bonds backing plate in a sputtering target?