METHOD FOR MANUFACTURING FLASH MEMORY DEVICE

摘要

PURPOSE: A method for manufacturing a flash memory device is to improve the barrier characteristic between a substrate and a well region by forming a diffusion barrier region between an n-well region and a p-well region. CONSTITUTION: The first photoresist pattern is formed on a substrate(31) with a field oxide film formed to expose a portion on which the first well region is formed. The substrate is implanted with an impurity opposite to the kind of the substrate to form the first well region. After the first photoresist pattern is removed, the second photoresist pattern(35) is formed on the substrate with a field oxide film formed to expose a portion on which the second well region is formed, and is executed by an ion implanting procedure to form a diffusion barrier region(36). The substrate is implanted with an impurity identical to the kind of the substrate to form the second well region. The substrate is annealed to activate the impurities of the first well region, the diffusion barrier region, and the second well region.