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微细化MOS存储器用硅单晶中的问题是缺陷,其发生的起因,在于衬底本身的结晶缺陷及器件制造工艺过程。由衬底结晶缺陷引起的缺陷有发生在表面的层错和发生在内部微小缺陷,因此,在研制低氧浓度单晶生成技术,控制硅氧化物析出的同时,再要防止研磨损伤就能降低这两种缺陷的密度。进一步利用氧的外扩散,能使离衬底表面大约5μm的范围基本无缺陷。 起因于工艺过程的缺陷随着微细化新工艺技术的引入,而有进一步增大的倾向。由于离子注入产生的损伤,反应性溅射腐蚀时的重金属污染,用电子束直接扫描而在图形锐角处的应力集中都会造成问题。这些问题可以通过使用低氧浓度衬底和改善工艺条件而得到解决。另外,全部工艺流程所造成的圆片翘曲度大约在20μm以内。 采用以上方法,我们对实现1个微米规范的微细化256K位MOS存储器寄与很大希望。
The problem in miniaturizing a silicon single crystal for MOS memory is a defect that occurs due to the crystal defects of the substrate itself and the device manufacturing process. Defects caused by substrate crystal defects include layer faults occurring on the surface and minor defects occurring in the interior. Therefore, in order to develop a single crystal production technique at a low oxygen concentration to control the deposition of silicon oxide and to prevent abrasion damage, The density of these two defects. Further utilizing the out-diffusion of oxygen, the range of about 5 μm from the surface of the substrate is substantially free from defects. Due to the process of defects with the introduction of miniaturization of new technology, but there is a tendency to further increase. Due to the damage caused by ion implantation, heavy metal pollution during reactive sputter corrosion, stress concentration at the sharp corners of the pattern with direct electron beam scanning can cause problems. These problems can be solved by using low oxygen concentration substrates and improving process conditions. In addition, the entire wafer warpage caused by the process is about 20μm. Using the above method, we are very hopeful to realize the miniaturization 256K MOS memorizer of 1 micron standard.