The present invention provides an electromagnetic wave shielding support base-attached encapsulant for collectively encapsulating a
semiconductor device mounting surface of a substrate having
semiconductor devices mounted thereon or a
semiconductor device forming surface of a
wafer having semiconductor devices formed thereon, the support base-attached encapsulant including a support base having an electromagnetic wave shielding property of 20 dB or more within a range of 100 MHz to 1,000 MHz, and an encapsulant composed of a thermosetting resin layer laminated on the support base. There can be provided a support base-attached encapsulant that can collectively encapsulate a
semiconductor device mounting surface of a substrate having the semiconductor devices mounted thereon or a
semiconductor device forming surface of a
wafer having semiconductor devices formed thereon without occurrence of warping of the substrate or the
wafer, peeling of the semiconductor devices from the substrate, and breakage of the wafer even in the case that a large-
diameter wafer or a large-area substrate such as inorganic, organic, or
metal substrate, especially thin one, is encapsulated, and that has excellent electromagnetic wave shielding property, reliability such as
heat resistance and
moisture resistance after encapsulating, and extremely high versatility,
mass-productivity, workability, and economical efficiency.