| 摘要 |
PURPOSE: A method for fabricating an isolation layer of a semiconductor device is provided to prevent dopants from migration in an interface between an N-well region and a P-well region by deeply etching the bottom of a trench and by performing a high density boron ion implantation process. CONSTITUTION: A pad oxide layer and a pad nitride layer are formed on a semiconductor substrate(210) having the first and second well regions to form a trench. The first oxide layer is formed on the resultant structure. A photoresist layer is deposited to completely fill the inside of the trench and is patterned to cover only the first well region including the half of the trench. The first oxide layer of the second well region is etched by using the photoresist layer as a mask so that the first oxide layer is left on the sidewall of the trench in the second well region and the semiconductor substrate on the bottom of the trench is exposed. The semiconductor substrate exposed to the bottom of the trench is etched and a boron ion implantation process is performed. The photoresist layer is removed. The second oxide layer(270) is formed to completely fill the inside of the trench. An annealing process is performed. The second oxide layer, the first oxide layer, the pad nitride layer and the pad oxide layer are sequentially etched. After a chemical mechanical polishing(CMP) process is performed, impurity ions are implanted into the first and second well regions to form an N-well and a P-well.
|
