By Applied Microengineering Ltd.
Various adhesives (epoxies, silicones, photoresists, polyimides, BCB, etc.) can be used to form wafer bonds.The adhesive can be applied by spinning, spraying, etc., and the process typically requires some heating (typically between room temperature and 400°C, depending on the adhesive/polymer being used) and pressure. AML also offers an in-situ UV cure system for use with appropriate adhesives, which provides rapid curing for high throughputs. The technique is tolerant to particles and is useful when the wafers have severe temperature limitations. Advantages of adhesive bonding: - Relatively low bonding temperatures (room temperature for UV-cure adhesives) - Compatible with CMOS - Various material combinations are possible - Tolerates topography and particle contamination - Wide range of adhesive materials available, including high transparency materials - Simple and low-cost process - No need for electric voltage or current Disadvantages - Intermediate layer - Non hermetic seal, outgassing of organic materials - Material flow may interfere with the device area and can cause issues with alignment Applications: - MEMS, 3D Integrated Circuits - Capping of BAW and SAW devices - Optical devices - Microfluidic devices - WLP - Temporary bonding
