A study on the effect of PECVD nitride process parameters on stress hysteresis Available to Purchase

In this paper we discuss the effect of the nitride process parameter on the stress hysteresis response were investigated. Various process condition based on existing production chamber which are silane, ammonia, nitrogen flow, electrode spacing, Radio Frequency (RF) power, chamber pressure. A definitive screening design method was adopted to analyze and model the effect of the response on the molecular bonding and the stress hysteresis. Analysis on the molecular bonding using the (Fourier Transform Infrared) FTIR analysis was also conducted to understand the bonding construction of the film based on these different process conditions. Bare silicon wafers were prepared and deposited using an AMAT Centura DxZ chamber with variation in the process parameters. These wafers were heat up using the thermal stress tool and stress changes were recorded. From the result it shows that the stress hysteresis relies on the hydrogen content of the nitride film. Silane, ammonia and RF power shows the most significant effect that affects the bonding behavior in the nitride film. The hysteresis response shows that the silane flow is the only parameter affecting the nitride film hysteresis with a total change of a 20-unit change from the low setting to the highest Silane flow setting. This behavior is attributed to the temperature range of the hysteresis setup which is done from 25°C to 450°C. From the correlation matrix we observed that the stress hysteresis is highly correlated with the hydrogen content of the film based on the FTIR measurement. This entails that the hydrogen content is a critical parameter to be understood in a nitride film since the final layer stress will change with thermal annealing which is ubiquitous in semiconductor.