Hi, I want to release my sacrificial LTO (deposited by LPCVD) layer uisng BHF/BOE, and would like to know wether the selectivity over silicon nitride (sputterred at room temperature and a rate of ~1.5nm/min) varies with the NH4F:HF ration in BOE? Does the selectivity increases or decreases with the ratio? Any answer will be appreciated. Thanks, Yu Wang