METHOD FOR FORMING SEPARATION REGION ON SILICON SUBSTRATE AND STRUCTURE OF SEPARATION REGION

PROBLEM TO BE SOLVED: To form an effective O2 diffusion barrier by forming a conformal layer that is selected from a group consisting of a double layer that is made of oxide and nitride in a separation groove and on a protection layer, depositing a CVD layer consisting of an oxide-filling material on the layer, and releasing the protection layer and the conformal layer. SOLUTION: A conformal layer 20 with a thickness of approximately 5-15mm being selected from a group consisting of an acid nitride, a double layer consisting of oxide and nitride, and a double layer consisting of acid nitride and nitride is formed on a protection layer (a pad nitride layer 14 and a pad oxide layer 12) and a separation groove (thermal oxide liner) 18. Then, an oxide-filling material 22 such as tetraethylortosilicate with a thickness of 450-500nm is deposited by the CVD supported by ozone, and the oxide-filling material 22 is subjected to anneal treatment and high-density treatment. Then, the conformal layer 20 and the pad nitride layer 14 and the pad oxide layer 12 are released. Then, the oxide-filling material 22 is flattened so that it is flush with the surface of a substrate.