| 摘要 |
PURPOSE:To reduce the manufacturing cost by specifying the number of layers when forming an active element of three-dimensional LSI, thereby obtaining the optimum number of the layers. CONSTITUTION:When forming active layers of three-dimensional LSI, the number of the layers is determined to the number designated by an equation. That is, when Y(K, M) represents full yield, Y0 is mean step yield of each step, n is the number of the steps of the single layer, a is a constant of proportion relating to the circuit density, D is a mean defect density, K is the number of active elements per chip, and m is the number of the layers of active element forming layers, Y(K, M)=y0<n>Mexp(-n.a.D.K<2>/M) is used, this is partially differentiated by M, and M0 of M=M0 obtained by differential Y/differential M=0 is determined as the number of the layers. Or, K, a, D, y0 are similarly used, the number M0 of the layers obtained by the equation of M0=K(a.D/¦logy0¦)<0.5> may be used. Thus, the number of the layers which can obtain the highest yield can be determined. |
