Reflow soldering device and reflow soldering method
AssigneeMitsubishi Electric Corporation
InventorsNoriyuki Besshi, Dai Nakajima, Hirotoshi Maekawa, Satoshi Ishibashi
Life of this patent
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Abstract
In the present invention, when a power module is soldered to a heatsink, steam which is temperature-adjusted to at least the melting point of a solder is introduced from a steam generating tank into the flow path provided in the heatsink, the heatsink is heated and the solder is melted. Inert gas is introduced into a soldering tank from another route so as not to mix with the steam supplied to the heatsink. Voids in the solder are reduced and condensed by pressure regulation and as a result the negative impact of voids is eliminated.
Claims12
A reflow soldering device, characterized by comprising:
- a soldered work to which solder is applied;
- a soldering tank in which to house a heating body that heats the soldered work;
- a vacuum pump with which an internal pressure of the soldering tank is reduced;
- a displacement gas tank from which an inert gas is introduced into the soldering tank;
- and
- a heat transfer medium supplying tank from which a temperature-adjusted heat transfer medium is supplied into a flow path provided in the heating body,
- wherein:
- the heat transfer medium is introduced into and discharged from the heating body by way of a route isolated from an internal space of the soldering tank;
- soldering of the soldered work is performed with the solder that melts with heat of the heating body;
- and
- the heat transfer medium is steam obtained by heating an inert liquid having a boiling point at least at a melting point of the solder or the inert liquid.
A reflow soldering method, characterized by comprising:
- disposing a soldered work to which solder is applied on a heating body in a soldering tank;
- reducing an internal pressure of the soldering tank;
- introducing an inert gas into the soldering tank;
- supplying a heat transfer medium which is temperature-adjusted at least to a melting point of the solder to a flow path provided in the heating body by a route isolated from an internal space of the soldering tank to melt the solder by heating the heating body and the soldered work;
- reducing voids in the solder by reducing the internal pressure of the soldering tank;
- and
- restoring the internal pressure of the soldering tank to at least a normal pressure to let the solder solidify.
Dependencies are inferred from the claim text.