PLASMA BONDING REPLACEMENT METHODS FOR TRADITIONAL BOND TECHNOLOGIES

摘要

Low Temp~® Plasma activated bonding is an enabling technology that is presently coming of age in mainstream production facilities. Bond activation is a means of catalyzing surfaces to become more reactive. The more reactive a surface becomes the more likely it is that the standard processing times and temperatures can be reduced relative to passivated surfaces. For example in SOI production wafer are bonded using a technique called fusion bonding or direct bonding. Wafer surfaces are rendered hydrophilic using wet chemical treatments such as SCI/RCA 1 solutions containing ammonium hydroxide and peroxide. The hydrophilic surface adhere to one another via van der Waals bonding but do not achieve a full bond strength needed for device applications until annealed at temperatures above 900℃. Substitution of oxygen plasma activation for the wet chemistry results in SOI production processes that are completed below 400℃ in less than 1 hr. Other processes long considered standard workhorses in the MEMS industry are also becoming less desirable as the device designs require more restrictive process window. The plasma activation technique can provide solutions for many of these common problems. How and why plasma activation can be used as an alternative bonding method in MEMS fabrication is discussed in detail in this paper.