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US 6,660,944 B1Granted
Circuit board having solder bumps
AssigneeNgk Spark Plug Co., Ltd.
InventorsHaruhiko Murata, Yukihiro Kimura, Masashi Inaishi
Life of this patent
Estimating the term…
Abstract
A circuit board having a plurality of solder bumps is provided. The solder bumps are flattened and leveled at the tops so that the coplanarity of the solder bumps is 0.5 μm or less per 1 mm. The flattened and leveled tops of the solder bumps are formed by cold pressing, hot pressing or grinding. Method of forming such solder bumps and jigs used for carrying out such methods are also provided.
Claims15
A circuit board produced by the process of:
- preparing a substrate having a joining surface;
- disposing a plurality of masses of solder paste on the joining surface of the substrate;
- heating and melting the masses of solder paste, thereby forming the masses of solder paste into a plurality of solder bumps on the joining surface of the substrate;
- and
- flattening and levelling tops of the solder bumps, thereby making smaller a coplanarity of the solder bumps;
- wherein the joining surface of the substrate has at least one curved portion in which at least one of the plurality of solder bumps is disposed on the at least one curved portion;
- and
- wherein, prior to the flattening and levelling step, tops of the plurality of solder bumps are not coplanar with each other due at least in part to the at least one curved portion.
5 more elements
A circuit board produced by the process of:
- preparing a substrate having a joining surface;
- disposing a plurality of masses of solder paste on the joining surface of the substrate;
- disposing a jig so that a flat surface of the jig is located at a predetermined position above the masses of solder paste;
- and
- heating and melting the masses of solder paste to bring tops of the masses of solder paste into contact with the flat surface of the jig, thereby forming the masses of solder paste into solder bumps having tops that are flattened and leveled in such a way as to make smaller a coplanarity of the solder bumps;
- wherein the joining surface of the substrate has at least one curved portion in which at least one of the plurality of solder bumps is disposed on the at least one curved portion;
- and
- wherein, prior to the heating and melting step, tops of the plurality of solder bumps are not coplanar with each other due at least in part to the at least one curved portion.
5 more elements
A method of producing a circuit board comprising:
- preparing a substrate having a joining surface;
- disposing of a plurality of masses of solder paste on the joining surface of the substrate;
- heating and melting the masses of solder paste, thereby forming the masses of solder paste into a plurality of solder bumps on the joining surface of the substrate;
- and
- flattening and levelling tops of the solder bumps thereby making smaller a coplanarity of the solder bumps,
- wherein the joining surface of the substrate has at least one curved portion in which at least one of the plurality of solder bumps is disposed on the at least one curved portion, and
- wherein, prior to the flattening and levelling step, tops of the plurality of solder bumps are not coplanar with each other due at least in part to the at least one curved portion.
4 more elements
A method of producing a circuit board comprising:
- preparing a substrate having a joining surface;
- disposing a plurality of masses of solder paste on the joining surface of the substrate;
- disposing a jig so that a flat surface of the jig is located at a predetermined position above the masses of solder paste;
- and
- heating and melting the masses of solder paste to bring tops of the masses of solder paste into contact with the flat surface of the jig, thereby forming the masses of solder paste into solder bumps having tops that are flattened and leveled in such a way as to make smaller a coplanarity of the solder bumps,
- wherein the joining surface of the substrate has at least one curved portion in which at least one of the plurality of solder bumps is disposed on the at least one curved portion, and
- wherein, prior to the heating and melting step, tops of the plurality of solder bumps are not coplanar with each other due at least in part to the at least one curved portion.
4 more elements
Dependencies are inferred from the claim text.