Method for preparing semiconductor device structure with isolation patterns having different heights

A method for preparing a semiconductor device structure, comprising:

• forming a target layer over a semiconductor substrate;
• forming an energy-sensitive layer over the target layer;
• performing a first energy treating process to form a plurality of first treated portions in the energy-sensitive layer;
• performing a second energy treating process to form a plurality of second treated portions in the energy-sensitive layer;
• removing the first treated portions and the second treated portions to respectively form a plurality of first openings and a plurality of second openings;
• transferring the first openings and the second openings into the target layer to respectively form a plurality of third openings and a plurality of fourth openings;
• transferring the third openings and the fourth openings into the semiconductor substrate to respectively form a plurality of fifth openings and a plurality of sixth openings;
• filling the fifth openings and the sixth openings with an isolation structure;
• and
• removing the target layer after the fifth openings and the sixth openings are formed in the semiconductor substrate;
• wherein the isolation structure has different heights in different cross-sections;
• wherein the first treated portions and the second treated portions extend along from different directions;
• wherein the first treated portions are parallel to each other, and wherein each of the second treated portions is located between and in direct contact with any two adjacent ones of the first treated portions.