Posted: March 16, 2014
Wafer bonding is widely used for packaging micro-fabricated devices such as microfluidic channels, microelectromechanical sensors (MEMS) and optical micro mirrors to ensure a mechanically stable and hermetically sealed encapsulation. This procedure involves heating the wafer, a thin slice of semiconductor material, up to its melting point and then cooling to surround the device. Unfortunately, the excessive heat can sometimes damage the device.
Microwave-bonding techniques that utilize susceptors to selectively heat the wafer have been proposed to solve this problem. Although microwave susceptors have been used for some time in the food industry to provide additional thermal heating on the outside of food articles to make food crispy on the outside and cause kernels to pop, susceptors for wafer bonding is an emerging research area. The susceptor is vulnerable to sudden arcing and micro-sized explosion, thereofre customized microwave cavities, solvents and conducting polymers have been used in combination with external metallic susceptors to heat wafers cuasing current microwave-bonding tecniques to be expensive and not accessible for widespread use.
Researchers at the University of Alberta have developed a novel low cost technique for applying localized heating for wafer bonding. THe new application is cost effective because it uses a conventional microwave oven as an energy source and specially designed metallic susceptors taht can produce controllable heating without arcing and or exploding. THe specific design of the metallic susceptor results in localized and selective heating of the wafer and not the device area. Since the wafer package is an important part of micro-fabricated devices to ensure their stability and function, this new technique offers the potential for a significant cost savings during production.
- Low cost alternative to current wafer bonding techniques
- Reduced production costs for micro-fabricated devices
- Faster bonding times
- Decreases contamination risk in micro-fluidic channels
The invention represents a valuable improvement for wafer bonding applications. The novel susceptor designs is ideal for bonding in microfluidics.
Technology Transfer Manager
TEC Edmonton – University of Alberta