Wafer Defects Issue Study In Lithography

Under the guidance of Moore’s Law, the semiconductor industry onto a new levelevery two to three years. Huge capital investment, higher technical engineer usagethan average proportion of the industrial sector, which led to the semiconductormanufacturing high cost sharing, coupled with fierce competition make product pricescontinued to decline, it drives most of the chip manufacturing operate in a large-scaleproduction and high yield levels. Maintaining and improving yield of thesemiconductor industry is essential, a high level of process yield is the key factor tothe reliable performance of chip and the proceeds.The important aspect of inhibit yield is that the defective wafers are generallybeyond repair. In some cases, the defective wafer is to downgrade and do low-endapplications. The scrapped wafer can be used as control wafer, these defects fromdifferent kinds of liquids, gases, clean room air, personnel, process, equipment andwater in wafer production areas. Particles and other small contaminants stay in theinternal or surface of the wafer, make it suffer surface contamination or form irregularisolated area. Many defects are generated in lithography, so solving the problem oflithography wafer defect has great significance to improve the chip yield.Firstly, giving a simple overview of microelectronics, integrated circuits and thebasic process of semiconductor manufacturing, then introducing the basic process oflithography and the desired material of lithography including Reticle,Light Sources,Scanner, Photo resist, Track. Most wafer defects have relationship with Track. So thispaper focuses on the structure and working principle of Track.This paper based on the actual production of lithography wafer defects issue,studied photoresist defects, particle defects, ring defects, scratch defects, ball defects,slash defects, single residue defects in depth and analysis of the factors that causewafer defects, found out a viable solution through experiments, reduced the productrework and scrap rates, and improved the production efficiency.