Reliability study of novel gate oxide process control method

As a key loop, gate oxide process loop is very necessary in logic schematic process flow. Especially in advanced semiconductor technology, intrinsic material properties of metal gate oxide have a major effect on device performance. So more accurate and precise inline metrology solutions for tightly gate oxide process controlling is very critical to monitor device performance. In the paper, the current metrology solution for gate oxide process controlling is investigated. It is found that the current WA T (wafer acceptance test) method solution is not convenient enough to control gate oxide process loop tightly, which needs long measure period and complex analysis model. Then a novel solution is proposed to measure bandgap during gate oxide manufacturing process which can represent electrical and intrinsic material properties of gate oxide. What's more it has following advantages: shorter measure period, simpler measure model and less measure parameters. More importantly the correlation between bandgap and the sub-threshold leakage current was investigated in the paper. It has been shown that bandgap has strong correlation with the sub-threshold leakage current. So bandgap measurement can be regarded as an effective inline metrology method for tightly gate oxide process controlling. And it is found that the novel solution is more accurate and precise to measure bandgap during gate oxide manufacturing process, which is significant for tightly gate oxide process controlling.