Field Oxide Thinning Behavior in Local Oxidation of Silicon Process under Enhanced Oxidation Conditions

Abstract

the dishing profille, a model which represents the pad by a network of springs, was introduced. We demonstrated that with this approach the experimental data are well fitted. With the equations presented and these models, erosion and dishing for metal CMP can be predicted. These calculations can be performed for different oxide and metal combinations with the knowledge of only a few parameters. This will help to reduce the time required to develop new technologies. AcknowledgmentsWe like to thank Ewald Giinther for valuable discussions. Technical assistance from Peter Schon is also grate-0,2 0,4 0,6 0,8 1,0 fully acknowledged. Cross section [pm]Fig. 11. Simulated dishing profiles (dashed lines) and AFM dishing data (solid line) for a 1 pm metal line. For the calculations, the downforce has been varied as indicated. ConclusionsWe discussed two major effects correlated with metal CMP: erosion and dishing. The presented experimental data revealed that the erosion increases linearly with polishing time and nonlinearly with pattern factor. The dishing within tungsten lines and contacts was found to depend on the type of oxide, on the pattern factor, and on the groove width, but not on the overpolish time. Deduced from Preston's law a set of equations was presented to fit the experimental data for erosion and dishing. To simulate ABSTRACT The field oxide thinning behavior in a modified local oxidation of silicon isolation process has been studied. The oxidation rates of silicon were deliberately modified by implantation or by high pressure oxidation (HiPOX). Although oxidation of heavily doped silicon with arsenic (As) or germanium (Ge) greatly enhanced the oxidation rate on the wide-field region, severe field oxide thinning was observed at the small isolation spacings. The dry HiPOX process also showed aggravated thinning compared to the atmospheric dry oxidation process. These results can be attributed to the increased oxide stresses during field oxidation due to low temperature and to fast oxidation rate, respectively. These results suggest that, in order to mitigate the thinning, the stress should be relieved by the slower oxide growth at the higher oxidation temperatures. Much reduced thinning was observed, as was expected, when the stress was relieved by introducing an interanneal during field oxidation.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.174.255.116 Downloaded on 2015-03-09 to IP

Experimental Study of Si3 N 4 Viscosity for Calibration of Stress‐Dependent Models of Silicon Oxidation

“…LOCOS isolation is still applied in ultralarge scale integration (ULSI) device manufacturing but requires careful tuning. [2][3][4] Its optimization can be efficiently carried out only with the assistance of process simulation means. [5][6][7] Existing two-and three-dimensional process simulators employ elaborate stress-dependent viscous and viscoelastic oxidation models.…”