Nitrogen flow rate purging effect

To verify that the beneficial effect of the ino-ease in the nitrogen flow rate is due to its purging effect, hydroxide activation has been stndied nsing other inert atmospheres (argon and helinm). The ACs have been prepared from an anthracite, keeping constant all the experimental variables. Table 1.9 snmmarizes porosity characterization of the samples prepared and shows that porosity development and yield are quite similar. From the isotherm shapes (not shown) and from the results in Table 1.9, it must be noted that porosity development follows the order He < Nj... 

The etch rates of oxides in DHF vary dramatically with their chemical composition and deposition conditions. Ideally, it would be possible to control the oxide etch rate by the concentration of DHF, and the copper etch rate with a second, independent variable. Figure 2 shows the results of cleaning metallic copper deposited on hydrophobic silicon from a copper-spiked HF solution [2]. SC-2 solutions with varying HCl and HjOj flows and a total flow of 1,760 ml/min were dispensed in the nitrogen-purged environment of a spray acid processor. The concentration of HCl had little effect on the total Cu removed as measrrred by TXRF. 

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