welcome. it is easy to tell you not read 'how to use this forum' as the subject line will be impossible to draw people who know about 'question' and even harder to reference in a search.
second, do some reading about microstepping. A stepper motor moves in whole, half of quarter steps. it does not micro-step.
Micro stepping is a means to attempt to create a pulse that simulates a wave so that the motor moves smootly as it ramps to speed.
As soon as power is lost, the motor will move to a whole step location. The magnets in the motor control that simple bit of physics.
You can prove that out very easily, take two magnets and hold one just a fraction off center of the other, then let go.
Your hand acts as the stepper driver, but without power, physics takes over and the motor will move to a full step.
700 microns is pretty sloppy in the CNC universe. most people start at about 13 microns and then get higher resolution without trying.
A simple 200 step motor on a 10 TPI lead screw with full steps is 2,000 steps per inch. (13 microns), with half stepping, it becomes higher resolution. (6.5 microns) Using a finer pitch will offer much finer resolution.
If you need to move under control, then you need to gear the device to be able to move in steps that result in an accuracy you need.
When you HOME or ZERO your movement it should be on a full step and always repeatable.
if you meant to say 1/700th of a micron, then you just need to full step with a worm gear.