You wish to find that value of the standard normal distribution to the left of which the area under the standard normal curve is 0.015 = 1.5 per cent.
Go to EXCEL or a similar package. I used OPENOFFICECALC. Type in 0.015 in any cell, say cell A1. Place cursor on "f_subx". It will say "function wizard". Find NORMSINV from the menu. Click on it. Enter the cell number (here A1) in between the parentheses. You will see -2.17009038. That is your answer. In other words,
P[ Z < -2.17009038] = 0.015
You can cross-check easily.