| 摘要 |
PURPOSE:To form adjoining P-type and N-type regions with a high accuracy by a method wherein the part of a region in which the first conductivity type impurity is implanted is covered and the second conductivity type impurity is implanted in the exposed part of the substrate and the quantity of the implanted second conductivity type impurity is the specific number of times of the quantity of the implanted first conductivity type impurity. CONSTITUTION:B ions of a quantity of 1X10<13>/cm<2> are implanted into the well forming part of a P-type Si substrate 1 through an SiO2 film 2 to introduce B atoms. A W metal film 3 and a PSG film 4 are formed and their predetermined parts are removed to form a mask pattern. Then P ions of a quantity of 2X10<11>/cm<2> are implanted to introduce P atoms. After that, the substrate 1 is subjected to heat treatment and the part of the substrate surface corresponding to the aperture part of the mask is oxidized to form an SiO2 film 5. Then P ions of a quantity of 2.5X10<13>/cm<2>, which is approximately twice a quantity of B ions, are implanted to introduce P atoms. After the PSG film 4 and the W film 3 are removed, B ions of a quantity of 3X10<11>/cm<2> are implanted to introduce B ions into the region of the substrate surface where the SiO2 film 3 is not formed. Finally, all the implanted ions are activated by annealing to form an N-type well region 6 and a P-type well region 7.
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