| 摘要 |
PROBLEM TO BE SOLVED: To improve flatness of a BPSG layer by forming a second BPSG layer on a first BPSG layer, and reflowing the second BPSG layer in a thermal processing. SOLUTION: A first BPSG(borophosphosilicate glas) layer 101 comprises 3-5% of boron dopant level and 4-5% of phosphorus dopant level and is deposited on a lower layer structure for about 30 minutes. On the first BPSG layer 101, a second BPSG layer 201 is formed using LPCVD with tetraethylorthosilicate as a reactive gas. The second BPSG layer 201 comprises 4-7% of boron dopant level and 1-4% of phosphorus dopant level and is reflowed in a thermal process. Thus, the second BPSG layer 201 is planarized.
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