Side Magnet Designs and Magnetic Field Effects on Effective Gap Filling of Longthrow Sputtering PVD for 3DIC Application

ThisstudyusedFiniteVolumeMethodtosimulatethemagneticprofileofPVD(physicalvapordeposition)chamber.Itcanbeapplied to different kinds of magnet arrangements to the longthrow sputtering PVD. For this long throw PVD, the best optimized process conditions and results from simulations included effects from chamber adaptor height, side magnet space, and magnet arangements. The side magnets consist of a total of 44 sets for one supporter around the chamber adaptor. Each set has three magnets. Each magnet has the magnetic field strength of 5,500 Gauss. The adaptor of gap filling chamber has a height of 120 mm and 44 sets of magnets around the adaptor. The polarity of side magnets is the same as the top magnets of the chamber. These magnets can very effectively increase of electron mobility and collision frequency with sputtered atoms. The plasma simulation result shows that the ionization rate on supttered atoms can be up to 26% from such a longthrow PVD system along with such magnets arrangement. Therefore, it shows a significant improvement on bottom side-wall step coverage in via hole up to 45%. The deposition rate increases by 40%. In addition, by adjusting RF bias and resputtering power, further improvement with 3/4 depth of side-wall step coverage by 30% and corner step coverage by 70% can be obtained. This study uses a simple method to apply to 3DIC gap filling capability for an increase of aspect ratio (AR). The improvement from this longthrow sputtering PVD with side magnets design around the adaptor not only results in low cost target design but also provides a very effective gap filling capability with higher deposition rate for 3DIC application. 3DIC (Three-dimensional Integrated Circuit) is a key technology for the semiconductor industry to keep up with Moore’s Law in the future. The semiconductor industry is always focusing on smaller and higher performing IC chips. In addition to widespread use of systemlevel packaging, lighter, greater signal transmission and less circuit interference devices are necessary, so 3DIC technology will be the main manufacturing technology for next generation products. 1‐3 By utilizingthethree-dimensionalTSV(Through-SiliconVia)technique, two-dimensional chips stack with each other in series that can achieve high-density and high-performance devices. This not only reduces power losses but also narrow the chip size. Following the smaller line width in devices and the increase in 3D stacking layers, this reduction of TSV width to less than one micrometer and increasing the TSV aspect ratio more than thirty appear to be the future trend. 4 There are increasingly more research topics about seed layer and barrier layer 4‐7 in TSV gap filling, and recent literature also focuses on how to use a strong magnetic field to fill high aspect ratio via in PVD processes. 6‐10 Moreover, recent studies have shown that the best magnet arrangements aiding and displaying to PVD process chamber can be received through simulation and analysis of the magnetic field. By aiding the magnets, the results showed an increase in plasma density and gas dissociation rate 11 in which a significant increase in the deposition rate from the sputtered atoms can be obtained. 11‐13 This work aims to create a simple and low cost way to increase the gapfilling capability and deposition rate of PVD equipment that can be applied to the semiconductor industry.