| 摘要 |
<p>A method for manufacturing a semiconductor device is provided to prevent damage of a semiconductor substrate due to an etching and to increase accuracy of overlay by forming an oxide layer before forming a poly silicon layer when an overlay aligning mark is formed. A pad oxide layer and a pad nitride layer are formed on an upper portion of a semiconductor substrate(100). An isolation region is etched to form a first trench. An HDP(High Density Plasma) oxide layer(130) gap-filling the first trench is formed. An isolation layer is formed by performing a planarization etching process to expose the pad nitride layer. The isolation layer is etched in a predetermined depth by the whole surface etching process to form a second trench. The pad oxide layer and the pad nitride layer are removed. An oxide layer(140) and a poly silicon layer(150) are formed on an upper portion of the second trench and the upper portion of the semiconductor substrate. The poly silicon layer is etched by a recess gate region formation process to form an overlay aligning mark where a step of the second trench is remained.</p> |
