| 摘要 |
PURPOSE:To easily obtain a device having a desired NOR type masked ROM by only activating the desired regions of resistors at the final stage of a wafer process. CONSTITUTION:A field oxide film 2, gate oxide film 4 and doped poly Si gate electrode 3 are selectively provided on a P type Si substrate 1 and an N type source 5, drain 6, and wiring layer 7 are made by implanting As ion. The layers 5-7 are covered with CVD-SiO2 8 and a high-temperature process is applied under N2 atmosphere to activate the layers 5-7. Then, a window is selectively opened to stack doped poly Si 9 and resistor 9 of a desired pattern is made. Then, PSG 10 is provided on the SiO2 8, resistor 9 and a Al wiring 11 is made by selective opening to cover the Al wiring 11 with PSG12. Next, baking is applied in N2 atmosphere including 10% of H2 at 450 deg.C, then, laser L is irradiated at the desired regions 3 of the resistors 9 in accordance with specifications for selective activation and the resistors 9 are set at a low resistance value. Therefore, a NOR type masked ROM IC can easily be formed. |
