Reducing program disturb in non-volatile storage using early source-side boosting

A method for operating non-volatile storage, comprising:

• boosting a first region of a substrate starting at a first time, a set of non-volatile storage elements is formed, at least in part, on the substrate, the set of non-volatile storage elements is associated with a set of word lines and includes at least one non-volatile storage element associated with a selected word line of the set of word lines;
• applying an isolation voltage to at least one isolation word line in the set of word lines on a source side of the selected word line, the first region extends under a plurality of word lines on a source side of the isolation word line in the substrate;
• boosting a second region of the substrate on a drain side of the isolation word line, the boosting of the second region starts at a second time which is after the first time, the second region extends under a plurality of word lines, including the selected word line, on the drain side of the isolation word line in the substrate;
• and
• applying a program voltage to the selected word line, the program voltage is applied starting at a third time which is after the second time, and ending at a fourth time which is after the third time, where the first region is boosted between at least the first and third times and the second region is boosted between at least the second and third times, but not between the first and second times, and the isolation voltage is applied at least between the first and fourth times.