A musical scale made entirely of half steps is called a "whole-half diminished scale," or simply a diminished scale. In this scale, each consecutive note is a half step apart. For example, starting on C, the scale would consist of the notes C, C#, D, D#, E, F, F#, and G.
Another possible interpretation could be that you are referring to a chromatic scale, which also consists of half steps, including all the pitches in an octave. If you need more specific information or context regarding these scales, feel free to ask!