摘要 |
PURPOSE: A method for forming an isolation layer of a flash memory device is provided to be capable of minimizing the generation of voids by partially filling a deep trench using a fluid oxide layer before completely filling the trench. CONSTITUTION: After defining a DTI(Deep Trench Isolation) region and a STI(Shallow Trench Isolation) region at a semiconductor substrate(10), a pad oxide layer(12) and a pad nitride layer(14) are sequentially formed on the semiconductor substrate. After forming deep trenches at the DTI region, a fluid oxide layer(20) is partially filled in the deep trenches. After forming shallow trenches at the STI region, an HDP(High Density Plasma) oxide layer(26) is completely filled in the deep and shallow trenches. Then, DTI and STI layers are formed by carrying out a planarization process on the resultant structure.
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