| 摘要 |
PROBLEM TO BE SOLVED: To provide a flattening method in which both global flatness and local flatness are achieved inside a semiconductor device. SOLUTION: A thermal oxide film 102 is formed on the surface of a silicon substrate 101, a pattern is formed, and grooves 103, 104 are formed by making use of the pattern as a mask. A TEOS-O3 NSG film 105 which depends on a substrate is formed on them under a condition that the ratio of O3 to TEOS is 10. After that, when the TEOS-O3 NSG film 105 is etched by 3% hydrofluoric acid, an etch rate ratio is 5. When the TEOS-O3 NSG film 105 on the thermal oxide film 102 is removed wholly, the NSG film 105 in about 1μm is left in recessed parts, and the grooves 103, 104 are flattened.
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