Joining sheet, electronic component, and producing method thereof
A joining sheet includes a solder layer which contains solder particles, a thermoplastic resin, and an active agent capable of activating the solder particles and a thermosetting resin-containing layer which is laminated on at least one surface in a thickness direction of the solder layer and contains a thermosetting resin.
1. A joining sheet comprising:
a solder layer which contains solder particles, a thermoplastic resin, and an active agent capable of activating the solder particles, but does not substantially contain a thermosetting resin; and
a thermosetting resin-containing layer which is laminated on at least one surface in a thickness direction of the solder layer and contains a thermosetting resin.
2. The joining sheet according to claim 1 , wherein
the thermosetting resin-containing layer further contains a thermoplastic resin and the content ratio of the thermosetting resin with respect to the thermosetting resin-containing layer is above 10 volume % and below 47.5 volume %.
3. The joining sheet according to claim 1 , wherein
the content ratio of the solder particles with respect to the solder layer is above 40 volume % and below 90 volume %.
4. The joining sheet according to claim 1 , wherein
the active agent is a carboxylic acid.
5. The joining sheet according to claim 1 , wherein
the thermosetting resin contains an epoxy resin.
6. The joining sheet according to claim 1 , wherein
the solder particles are made of a tin-bismuth alloy.
7. The joining sheet according to claim 1 , wherein
the thermosetting resin-containing layer further contains a curing agent and a curing accelerator.
8. The joining sheet according to claim 1 , wherein
the thermosetting resin-containing layer is also laminated on the other surface in the thickness direction of the solder layer.
9. A method for producing an electronic component comprising the steps of:
preparing a laminate in which a joining sheet is disposed between two pieces of wired circuit boards arranged so that corresponding terminals thereof are spaced in opposed relation to each other, wherein
the joining sheet comprises
a solder layer which contains solder particles, a thermoplastic resin, and an active agent capable of activating the solder particles, but does not substantially contain a thermosetting resin, and
a thermosetting resin-containing layer which is laminated on at least one surface in a thickness direction of the solder layer and contains a thermosetting resin; and
heating the laminate at a temperature that is not less than the melting point of the solder particles.
10. An electronic component obtained by a method for producing an electronic component, wherein
the method for producing an electronic component comprises the steps of:
preparing a laminate in which a joining sheet is disposed between two pieces of wired circuit boards arranged so that corresponding terminals thereof are spaced in opposed relation to each other, and
the joining sheet comprises
a solder layer which contains solder particles, a thermoplastic resin, and an active agent capable of activating the solder particles, but does not substantially contain a thermosetting resin, and
a thermosetting resin-containing layer which is laminated on at least one surface in a thickness direction of the solder layer and contains a thermosetting resin; and
heating the laminate at a temperature that is not less than the melting point of the solder particles.