Lead-free solder composition with Bi, In and Sn
AssigneeFujitsu Limited
InventorsMasayuki Kitajima, Masakazu Takesue, Yasuo Moriya, Yoshinori Nemoto, Yumiko Fukushima
Life of this patent
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Abstract
A lead-free solder alloy composition contains Sn, Bi and In, with respective contents such that the solder alloy composition provides a liquidus temperature below the heat resistant temperature of a work to be soldered. The alloy contains not more than about 60 wt % Bi; not more than about 50 wt % In; optionally at least one element selected from Ag, Zn, Ge, Ga, Sb, and P; and Sn. Also, lead-free solder powders containing same, and printed circuit boards, electronic components and electronic apparati employing such alloy.
Claims12
A lead-free solder alloy composition comprising Sn, Bi and In, said solder alloy containing Sn, Bi and In with respective concentrations set such that said lead-free solder alloy composition has a melting temperature lower than a predetermined heat-resistant temperature of a work to be soldered, wherein said solder alloy composition contains Bi with an amount of approximately 55.0 wt %, In with an amount of approximately 5.0 wt %, and Sn with an amount of about 40.0 wt %.
A lead-free solder alloy composition comprising Sn, Bi and In, said solder alloy containing Sn, Bi, and In with respective concentrations set such that said lead-free solder alloy composition has a melting temperature lower than a predetermined heat-resistant temperature of a work to be soldered, wherein said solder alloy composition contains Bi with an amount of approximately 46.0 wt %, In with an amount of approximately 20.0 wt %, and Sn with an amount of approximately 34.0 wt %.
A lead-free solder powder comprising:
- a plurality of lead-free solder particles each having a generally spherical shape with a diameter of 20-60 μm and consisting essentially of Bi, In and Sn;
- each of said lead-free solder particles containing Bi with an amount of approximately 55 wt %, In with an amount of approximately 5.0 wt %, and Sn with an amount of approximately 40.0 wt %.
A printed circuit board, comprising:
- a substrate;
- a conductor pattern provided on said substrate;
- and
- a lead-free solder alloy covering said conductor pattern, said lead-free solder alloy consisting essentially of Sn, Bi and In, with respective concentrations set such that said lead-free solder alloy has a melting temperature lower than a predetermined heat-resistant temperature of a component to be soldered upon said substrate,
- said solder alloy containing Bi with an amount of approximately 55 wt %, In with an amount of approximately 5.0 wt %, and Sn with an amount approximately 40.0 wt %.
An electronic component, comprising:
- an electronic component body;
- an electrode projecting from said electronic component body;
- and
- a lead-free solder alloy covering said electrode consisting essentially of Bi, In and Sn, said lead-free solder alloy containing Bi with an amount of approximately 55 wt %, In with an amount of approximately 5.0 wt %, and Sn with an amount of approximately 40.0 wt %, such that said lead-free solder particle has a melting temperature lower than a predetermined heat-resistant temperature of said electronic component.
An electronic apparatus, comprising:
- a substrate;
- a conductor pattern provided on said substrate;
- an electronic component mounted upon said substrate in electrical connection with said conductor pattern, said electronic component having an electrode projecting therefrom;
- and
- a lead-free solder alloy connecting said electrode to said conductor pattern, said lead-free solder alloy consisting essentially of Bi, In and Sn and containing Bi with an amount of approximately 5.0 wt %, In with an amount of approximately 5.0 wt %, and Sn with an amount of approximately 40.0 wt %, such that said lead-free solder particle has a melting temperature lower than a predetermined heat-resistant temperature of said electronic component.
A lead-free solder powder comprising:
- a plurality of lead-free solder particles each having a generally spherical shape with a diameter of 20-60 μm and consisting essentially of Bi, In and Sn;
- each of said lead-free solder particles containing Bi with an amount of approximately 46.0 wt %, In with an amount of approximately 20.0 wt %, and Sn with an amount of approximately 34.0 wt %.
A printed circuit board, comprising:
- a substrate;
- a conductor pattern provided on said substrate;
- and
- a lead-free solder alloy covering said conductor pattern, said lead-free solder alloy consisting essentially of Sn, Bi and In, with respective concentrations set such that said lead-free solder alloy has a melting temperature lower than a predetermined heat-resistant temperature of a component to be soldered upon said substrate,
- said solder alloy containing Bi with an amount of approximately 46.0 wt %, In with an amount of approximately 20.0 wt %, and Sn with an amount of approximately 34.0 wt %.
An electronic component, comprising:
- an electronic component body;
- an electrode projecting from said electronic component body;
- and
- a lead-free solder alloy covering said electrode consisting essentially of Bi, In and Sn, said lead-free solder alloy containing Bi with an amount of approximately 46.0 wt %, In with an amount of approximately 20.0 wt %, and Sn with an amount of about 34.0 wt %, such that said lead-free solder particle has a melting temperature lower than a predetermined heat-resistant temperature of said electronic component.
An electronic apparatus, comprising:
- a substrate;
- a conductor pattern provided on said substrate;
- an electronic component mounted upon said substrate in electrical connection with said conductor pattern, said electronic component having an electrode projecting therefrom;
- and
- a lead-free solder alloy connecting said electrode to said conductor pattern, said lead-free solder alloy consisting essentially of Bi, In and Sn and containing Bi with an amount of approximately 46.0 wt %, In with an amount of approximately 20.0 wt %, and Sn with an amount of about 34.0 wt %, such that said lead-free solder particle has a melting temperature lower than a predetermined heat-resistant temperature of said electronic component.
Dependencies are inferred from the claim text.