JP2004158898A5 - - Google Patents

Claims (22)

A method for producing a mounting structure comprising a printed circuit board and an electronic component mounted on the printed circuit board and containing Pb in a lead plating film,
A mounting step of attaching a solder paste made of an Sn-Zn alloy having a Bi content of less than 3% to the printed board, and mounting the electronic component on the printed board through the solder paste;
A heating step to heat and melt the solder paste attached on the printed circuit board;
The solder is forcibly cooled at a cooling rate of not less than 1.5 ° C./second and not more than 3.3 ° C./second from the state in which Pb contained in the plating film of the lead of the electronic component is dissolved in the solder. And a cooling process for solidifying the mounting structure. The mounting structure manufacturing method according to claim 1, wherein the heating step heats the solder paste to 210 ° C. or higher. The said cooling process is a manufacturing method of the mounting structure of Claim 1 which cools the said solder to 190 degrees C or less. The method for manufacturing a mounting structure according to any one of claims 1 to 3, wherein the solder paste is a paste formed by combining two or more kinds of solder powders. A first reflow process for soldering and mounting electronic components mounted on one surface of the printed circuit board through the mounting process through the heating process and the cooling process;
A second reflow step of mounting the electronic component mounted on the other surface of the printed circuit board through the mounting step by soldering through the heating step and the cooling step; and
In the cooling step in the second reflow step, the solder on both sides of the printed circuit board heated and melted in the heating step in the second reflow step is forcibly forced from the molten state with the cooling rate. The method for manufacturing a mounting structure according to any one of claims 1 to 4, wherein the mounting structure is cooled and solidified. An electronic component mounted on one surface of the printed circuit board through the mounting process, and soldering and mounting through the heating process and the cooling process; and
An electronic component in which a lead is inserted and mounted from one surface side of the printed circuit board into a through hole of the printed circuit board is set to a temperature of 170 ° C. or less at a solder joint portion by a reflow process on the one surface side of the printed circuit board. The manufacturing method of the mounting structure of Claim 5 which has the flow process soldered by the flow in a state. The said flow process performs temperature adjustment of the said solder joint part by the said reflow process by blowing cooling air to the said solder joint part by the said reflow process of the one surface side of the said printed circuit board. Method for manufacturing the mounting structure. The method for manufacturing a mounting structure according to claim 7, wherein the cooling air is N 2 gas. The flow step adjusts the temperature of the solder joint by arranging the solder joint of the electronic component mounted on one surface of the printed circuit board and a heat insulating material on the other surface. Item 9. The method for manufacturing a mounting structure according to any one of Items 6 to 8. The method for manufacturing a mounting structure according to claim 9, wherein the heat insulating material is a masking tape attached to the printed circuit board. The method for manufacturing a mounting structure according to claim 9, wherein the heat insulating material is a tray on which the printed circuit board is installed. A mounting structure in which an electronic component including Pb in a lead plating film is soldered and mounted on a printed circuit board,
The electronic component is
From the state in which Pb contained in the lead plating film is dissolved into the solder obtained by heating and melting the solder paste made of the Sn—Zn alloy having a Bi content of less than 3%, 1.5 ° C./min. 3. A mounting structure that is bonded to the printed board with the solder that has been cooled and solidified at a cooling rate of 3.3 ° C./less. The mounting structure according to claim 12, wherein the solder paste is heated to 210 ° C. or higher to be in a molten state. The mounting structure according to claim 12, wherein the solder is cooled to 190 ° C. or less at the cooling rate. The mounting structure according to any one of claims 12 to 14, wherein the solder paste is a paste formed by combining two or more kinds of solder powders. On one surface side of the printed circuit board, the electronic component is joined by the solder obtained by overheating and melting the solder paste,
On the other surface side of the printed circuit board, after the electronic component is bonded on the one surface side, the electronic component is bonded with the solder obtained by overheating and melting the solder paste,
16. The solder according to claim 12, wherein the solder on the other surface side is cooled at the cooling rate, and the solder on the one surface side is also melted again and then cooled at the cooling rate. The mounting structure described. The electronic component is bonded to the one surface side of the printed circuit board by the solder obtained by heating and melting the solder paste,
On the other surface side of the printed circuit board, after the electronic component is bonded on the one surface side, an electronic component is mounted by inserting a lead from the one surface side into a through hole of the printed circuit board. The mounting structure according to claim 16, which is joined by a flow in a state in which a temperature of a solder joint portion in the reflow process on the one surface side is set to 170 ° C. or less. The mounting structure according to claim 17, wherein a temperature of the solder joint portion in the reflow process during the flow process is adjusted by blowing cooling air to the solder joint portion. The mounting structure according to claim 25, wherein the cooling air is N2 gas. The mounting structure according to any one of claims 18 to 19, wherein the temperature of the solder joint portion in the reflow process during the flow processing is adjusted by disposing a heat insulating material on the other surface side. The mounting structure according to claim 20, wherein the heat insulating material is a masking tape attached to the printed circuit board. The mounting structure according to claim 21, wherein the heat insulating material is a tray on which the printed circuit board is installed.