| 摘要 |
PURPOSE:To prevent erroneous operation (soft error) by providing a shielding to shield alpha ray arising from a seal near the top of a semiconductor element of a device wherein the semiconductor element like a dynanic memory is sealed by a sealing body. CONSTITUTION:Several ppm of U or Th is contained in a material like ceramic package to seal dynamic RAM consisting of a plural MISFET, and since these impurities emit alpha ray, a soft error on memory may result, however, alpha ray can be prevented from incoming by shielding the memory surface with a high purity material. In case, for example, an element pellet 2 is sealed with a support substrate 1 and a cap 10 of alumina ceramic, a high purity material plate 11 of Si in which impurities are not contained or a material 12 for which silicone rubber or polyamide resin is hardened is fixed inside the cap 10 facing the pellet 2. Thus, alpha ray is shielded easily, and erroneous operation can be prevented accordingly. |
