METHOD FOR FORMING TRENCH ISOLATION LAYER

摘要

PURPOSE: A method for forming a trench isolation layer is provided to prevent generation of a stringer in a gate pattern forming process by forming the second mask pattern having a sidewall of a negative slope. CONSTITUTION: The first mask patterns are formed on a semiconductor substrate(100). The width of a lower portion of the first mask patterns is wider than the width of an upper portion of the first mask patterns. The second mask patterns are formed between the first mask patterns by using the first mask patterns as a mold. The width of a lower portion of the second mask patterns is narrower than the width of an upper portion of the second mask patterns. The semiconductor substrate(100) is exposed by removing selectively the first mask patterns. A trench(130) is formed by etching the semiconductor substrate(100). An isolation layer pattern(140) is formed by etching an isolation layer. The second mask pattern is removed from the semiconductor substrate(100).