Self-aligned wet etching process

A self-aligned wet etching process, comprising the steps of:

• Step S1:
• etching a substrate including an etch protection layer on a surface thereof to form a plurality of trenches spaced from each other;
• Step S2:
• sequentially forming an insulating layer and an etch stop layer on a surface of each of the plurality of trenches to form an accommodation space inside the etch stop layer;
• Step S3:
• filling a primary insulator inside the accommodation space, wherein the primary insulator integrates with the etch stop layer and the insulating layer to form a multi-layer isolator;
• Step S4:
• removing the etch protection layer to expose a portion of the isolator outside the substrate;
• Step S5:
• removing the insulating layer exposing outside the substrate through a wet etching solution, wherein the primary insulator is protected by the etch stop layer and exempted from being etched by the wet etching solution;
• Step S6:
• removing the etch stop layer exposing outside the substrate to expose a portion of the primary insulator outside the substrate;
• and
• Step S7:
• forming a plurality of electric contactors on the substrate that are separated by the primary insulator,
• wherein in the Step S1, the substrate is etched in a first direction and a second direction vertical to the first direction to respectively faun a plurality of first trenches spaced from each other and a plurality of second trenches spaced from each other with a plurality of pillars formed between the plurality of first trenches and the plurality of second trenches.