| 摘要 |
PURPOSE:To prevent excess annealing of a lower layer LSI when the impurity regions are to be formed in the respective layers of a multilayer LSI of semiconductor device by a method wherein after impurities are introduced respectively in the respective layers, the heat treatment for activation is performed. CONSTITUTION:An insulating layer 2 is formed on a single crystal substrate 1, and a single crystal polysilicon layer is formed on the upper face thereof. Then impurity diffusion and gate oxidation are performed to the single crystal silicon layer thereof to form the first layer LSI (arrow markI). The same process is repeated thereafter to form the second layer LSI, th third layer LSI (arrow marks II, III). After the LSI's of the whole layers are completed, the heat treatment is performed to activate impurities introduced in the respective layers. Because annealing for activation of impurities is performed finally in the lump at the stage when the whole layers are completed, not performing at every layer by this way, excess annealing of the lower layer LSI can be prevented. |
