Importance of rapid photothermal processing in defect reduction and process integration

Abstract

Until recently, furnace processing had been one of the most popular methods for the manufacturing of the entire spectrum of semiconductor devices. As a result of shrinking device geometries and increasing wafer size, current trends are in the direction of single wafer processing. There is also a drive towards methods that address the long term requirements for reduced microscopic defects, lower processing temperatures, lower cost of ownership, reduced cycle times, smaller feature sizes and environmentally friendly processing of future generations of integrated circuits. The drive towards such an innovative process has stimulated higher heating and cooling rates along with the compatibility with single wafer technology make rapid thermal processing (RTP) as one of the most promising new thermal processing techniques. Recently introduced minifurnaces as well as RTP systems based on resistive heaters can also provide compatible heating and cooling rates. However, in terms of microscopic defeat reduction, thermal and residual stress reduction, as well as other processing needs, resistive heaters based RTP or minifurnaces do not offer any advantages over conventional furnace processing. Recently, we have shown that ultra violet (UV) and vacuum ultra violet (WV) light sources when used in conjunction with tungsten halogen lumps based RTP can provide a process with lowest microscopic defects, lowest thermal and residual stress as well as built in green manufacturing feature. Rapid photothermal processing (RPP) also providing a platform for some of the fastest cycle times ever reported. This paper presents new results about the importance of RPP in achieved the desired performance of future semiconductor devices.RPP has been applied to several semiconductor processes and the results are very imprwsive. Some of the results are listed:1. High-K dielectric deposittion: RPP CVD has been used to deposit PLZT, Ta205, Y20ri, etc. Reduction in defects in high-K dielectrics is very crucial as these form the gate dielectric materials in MOS devices as well as the dielectric layer of the DRAM capacitor it is hence very important to use a process that can give a good quality deposition at a reduced temperature. Recent results show that the activation energy of the mass transport limited deposition 0-7803-4050-7/97/$10.00 01997 IEEE 245 region is also reduced. Measurements of the dielectric C-,V and I-V characteristics show a very low loss factor and low leakage current. The photo enhanced quantum mechanical barrier lowering is the reason for reduced defects. Metallization:RPP was used to form metallic ohmic contacts. The process cycle time was reduced by over 40 seconds as compared to RTP, demonstrating the effectiveness of the usage of light energy in semiconductlor processing. Moreover the defect in the case of front irradiation are lesser than the case with an increased temperature and time in the back irradiation. Statistical analysis shows a remarkable correlation factor in the ord'er of 0.95 for the experimental data and the t...

Prospects of manufacturing organic semiconductor-based integrated circuits

“…Thus from manufacturing point of view, RPP will provide better performance, reliability, and yields. In two recent publications [121], [122], we have discussed the process integration and defect reduction issues at length. 2) In case of RPP assisted CVD, the process activation energy is reduced both in nucleation growth and bulk transport regions [123].…”