| 摘要 |
PURPOSE:To make a software error rate less than 75 fits, by performing direct sealing by using a sealing resin including a filler, in which the amount of inclusion of uranium and thorium is less than 0.2 p.p.b. CONSTITUTION:A semiconductor memory element having the integration degree of 16 K bits or more is directly sealed by a resin including a high purity filler. In the sealing resin, the amount of inclusion of uranium and thorium is less than 0.2 p.p.b. When the total amount of inclusion of uranium and thorium is made less than 0.2 p.p.b, the occurring rate of software errors can be reduced to less than 75 fits. Since the element is directly sealed, the forming work of a shielding film is not required. Therefore only the sealing work is enough and cracks are hard to occur in the sealing body even in heating cycles and the like. Thus, the highly reliable semiconductor memory element can be obtained. |
