Electromagnetic-wave shielding sheet and electronic component-mounted substrate
An electromagnetic-wave shielding sheet is an electromagnetic-wave shielding sheet used to form an electronic component-mounted substrate, the electronic component-mounted substrate including an electromagnetic-wave shielding layer covering at least a part of a step part and an exposed surface of a substrate, in which the electromagnetic-wave shielding sheet is a laminate including a cushion layer and a conductive layer, the conductive layer is an isotropic conductive layer containing a binder resin and a conductive filler, a thickness of the conductive layer is 8 to 70 μm, and a content of the conductive filler in a region on a side opposite to a cushion layer side in the conductive layer is larger than that in a region on the cushion layer side in the conductive layer.
1. An electromagnetic-wave shielding sheet used to form an electromagnetic-wave shielding layer constituting a part of an electronic component-mounted substrate,
the electronic component-mounted substrate comprising:
a substrate;
an electronic component mounted on at least one surface of the substrate; and
the electromagnetic-wave shielding layer covering at least a part of a step part formed due to mounting of the electronic component and an exposed surface of the substrate, wherein
the electromagnetic-wave shielding sheet is a laminate including a cushion layer and a conductive layer,
the conductive layer is an isotropic conductive layer containing a binder resin and a conductive filler,
a thickness of the conductive layer is 8 to 70 μm, and
a content of the conductive filler in a region on a side opposite to a cushion layer side in the conductive layer is larger than the content of the conductive filler in a region on the cushion layer side in the conductive layer.
2. The electromagnetic-wave shielding sheet according to claim 1 , wherein the conductive layer is a laminate of at least two isotropic conductive layers containing different amounts of the conductive filler.
3. The electromagnetic-wave shielding sheet according to claim 1 , wherein,
in the conductive layer, on a cross section thereof in a thickness direction,
a conductive filler occupation area ratio (A) in a region from a side opposite to a cushion layer side to 30% of the thickness is 25 to 55%,
a conductive filler occupation area ratio (B) in a region from the cushion layer side to 30% of the thickness is 15 to 40%, and
the conductive filler occupation area ratio (A) is higher than the conductive filler occupation area ratio (B).
4. The electromagnetic-wave shielding sheet according to claim 3 , wherein a difference of the conductive filler occupation area ratio between the conductive filler occupation area ratios (A) and (B) expressed by: Conductive Filler Occupation Area Ratio Difference (%)=Conductive Filler Occupation Area Ratio (A)−Conductive Filler Occupation Area Ratio (B) (Expression (1)) is 1 to 31%.
5. The electromagnetic-wave shielding sheet according to claim 1 , wherein the conductive layer includes holes.
6. An electronic component-mounted substrate, comprising:
a substrate;
an electronic component mounted on at least one surface of the substrate; and
an electromagnetic-wave shielding layer formed by an electromagnetic-wave shielding sheet according to claim 1 , wherein
the electromagnetic-wave shielding layer covers at least a part of a step part formed due to mounting of the electronic component and an exposed surface of the substrate.