FSG Film Quality Improvement In Damascus Copper Process

With the development of the technology, the application of integrated circuits plays a more important role in human being's life. More and more IC devices are used in differenct application. Consequently, higher performance & lower power consumption have been the basic requirement for IC industry. The countless new structurse, materials and technologies come forth, like strained silicon, SOI, copper interconnect and etc. With these, VLSI chases the extreme of performance. Meanwhile, it is also facing all sort of design and process problem by all time. This paper will focus on the 1^st generation low-K material, FSG, and will discuss how to remove defect and prevent the recurence.In the development of IC technology, the replacement from aluminum interconnection to copper's is a remarkable milestone. The innovation of Dual-Damascus process introduces copper as the conductor successfully. With many good character, like lower resistance, better thermal stability, the dense circuit network formed by copper has better performance than Al process'. It achieved the small chip size cooperated with low-k dielectric material while the device performance keep improving continuously.This paper studied a crystal-liked hexagonal defect on the FSG surface. It sizes about 1 micron. In Dual-Damascus process, the hit-rate of this defect is very high and the totla count within one wafer is very large, hance the real yield killers are hided among these crystal defects. We lost the chance to make an accurate an timly assessment about production and trigger early warning. In some cases, the crystal defect played as the yield killer by itself. Utilized the existing resources in the FAB, such as SEM, defect scan tool, EDX, FTIR, and so on, We collected as more information about this defect as we can. As a starting point, We found several approachs to reduce the occurrence of Crystal Defect based on a large number of experiments. Combined with the actual production requirements, selected the most feasible and effective improvement method which has the smallest impact on electrical properties.