| 摘要 |
A method for forming wells of a semiconductor device, comprising the steps of forming a plurality of field insulating layers on a field region of a semiconductor substrate; forming first impurity regions of a first conductive type at a first depth beneath a surface of the semiconductor substrate; forming first impurity regions of a second conductive type beneath the surface of the semiconductor substrate at a second depth between the field insulating layers; selectively forming second impurity regions of the second conductive type in the first impurity regions of the first conductive type between adjacent field insulating layers; forming second impurity regions of the first conductive type in the first impurity regions of the second conductive type at both sides of the second impurity regions of the second conductive type; and diffusing the first and second impurity regions of the first conductive type and the first and second impurity regions of the second conductive type by a drive-in process to form a first conductive type shield region, a first conductive type well, and first and second wells of a second conductive type.
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