JP4833927B2 - Soldering method and soldering apparatus - Google Patents

Description

  The present invention relates to a soldering method and a soldering apparatus for mounting an insertion type electronic component on a mounting board on which a printed wiring board or a surface mounting component is mounted using a lead-free solder material.

  In recent years, there has been a strong demand for improvement in the reliability characteristics of electronic circuit boards built in as electronic devices have higher performance and diversified environments. For this reason, in electronic component mounting, there is an increasing demand for improving reliability characteristics such as mechanical strength and thermal shock strength of a solder joint formed by soldering an electronic component to a substrate.

  In addition, solder materials used for soldering electronic components to printed circuit boards are subject to laws and regulations concerning the removal of lead from waste products and the prohibition of use of lead from the viewpoint of global environmental protection. Switching to lead-free solder materials that do not contain it is progressing.

  In the flow soldering of insertion-type electronic components using lead-free solder materials to the circuit board, soldering defects such as lift-off and shrinkage can be caused by segregation of solder additive elements in the solder material and the original solder composition. It is known that this is caused by the formation of a fragile alloy with a low melting point different from that of the solder. By rapidly solidifying the solder, the segregation phenomenon is alleviated and the growth time of the fragile alloy phase is reduced. It is said that shortening is effective in reducing the above-mentioned problems.

  The following manufacturing methods and soldering methods have been proposed for the purpose of improving the connection reliability between the electronic component and the substrate by suppressing the occurrence of lift-off, shrinkage and the like, which are defects in soldering.

  Japanese Patent Application Laid-Open No. 11-354919 discloses a cooling zone partitioned by a heat shield immediately after flow soldering in a flow soldering method for mounting an electronic component on a substrate using a lead-free solder material containing Bi. And the temperature range from the liquidus temperature vicinity to the solidus temperature vicinity is cooled at about 10 to 20 ° C./second, and the second cooling rate: the temperature range near the solidus temperature is about 0. A method of manufacturing an electronic circuit board that has been gradually cooled at 1 to 5 ° C./second to suppress lift-off and improve connection reliability is described (Patent Document 1).

  Japanese Patent Laid-Open No. 2001-15903 discloses a flow soldering method in which an electronic component is mounted on a substrate using a lead-free solder material. After the process, the circuit board is cooled in a rapid cooling process by a refrigerant liquid having a temperature lower than 1/2 of the soldering temperature or a temperature selected in advance of 20 ° C. to 120 ° C., and cracks in the solder joints (lift-off phenomenon) ) Has been described (Patent Document 2).

  Japanese Patent Laid-Open No. 2002-141658 includes a cooling chamber device in a flow equipment line for transporting a substrate by a conveyor in flow soldering for mounting an electronic component on a substrate using a lead-free solder material, and a flow An adjustment zone is provided between the tank and the cooling chamber device to suppress the soaking of the substrate and the solder from starting to solidify, and after the solder material melted in the solder material supply zone is attached to a predetermined portion of the substrate, A soldering method and apparatus in which the solder material adhering to the substrate in the adjustment zone is soaked in a molten state and rapidly cooled in the cooling zone, for example, about 300 ° C./min to 500 ° C./min to reduce the occurrence of lift-off. (Patent Document 3).

Japanese Patent Laid-Open No. 11-354919 JP 2001-15903 A JP 2002-141658 A

  However, in Patent Document 1, a heat shield plate is provided between the flow zone and the cooling zone. However, the temperature difference between the flow zone and the cooling zone, and the substrate being conveyed by the belt, the leading edge and the trailing edge of the substrate. Then, a difference occurs in the cooling temperature, and the entire substrate cannot be cooled at a uniform cooling rate. In addition, there is no description about the size of the substrate, and in the case of a large substrate, the difference in the cooling temperature between the front and rear ends of the substrate becomes more significant, and solidification may have started before reaching the cooling zone. There is a problem that the entire substrate cannot be cooled at a uniform cooling rate.

  In Patent Document 2, a rapid cooling unit is provided in the flow soldering equipment line. However, the temperature difference between the flow zone and the rapid cooling zone and the substrate being conveyed by the belt allow cooling at the front and rear ends of the substrate. There is a problem that the temperature is different and the entire substrate cannot be cooled at a uniform cooling rate.

  In Patent Document 3, measures are taken to prevent solder solidification and solder solidification before cooling by providing an adjustment zone in front of the cooling zone, but the temperature difference between the adjustment zone and the cooling zone. Since the substrate is conveyed from the adjustment zone to the cooling zone by the belt conveyor, there is a problem in that the cooling rate is different between the front end and the rear end of the substrate, and the entire substrate cannot be cooled at a uniform cooling rate.

  According to the above Patent Documents 1 to 3, when the substrate is transported from the flow zone or the adjustment zone to the cooling zone by a conventional belt conveyor, the length of the substrate enters the cooling zone, that is, the tip of the substrate, There is a problem that a temperature difference occurs on the surface of the substrate at the center and the rear end, a difference occurs in the cooling rate at the front end, the central portion, and the rear end of the substrate in the transport direction, and the entire substrate cannot be cooled at a uniform cooling rate. For this reason, it became clear that the cooling conditions of each solder joint on the substrate are different, and the quality of soldering of electronic components varies.

  The present invention relates to the occurrence of lift-off and shrinkage in soldering in which an insertion-type electronic component is mounted on a lead-free printed circuit board on which a printed wiring board or surface-mounted component is mounted using a lead-free solder material. To provide a soldering method for a printed wiring board or a printed circuit board substrate that is excellent in the reliability of solder joint between an electronic component and a board by reducing soldering, and a soldering apparatus that enables the soldering method With the goal.

The printed wiring board or printed circuit board soldering method according to the first aspect of the present invention is a lead-free solder material for a printed circuit board on which a printed wiring board or a surface-mounted component is mounted using a conveyor type soldering apparatus. Soldering the printed wiring board or the printed circuit board on which the lead terminal is inserted into the through hole and mounting the insertion type electronic component, and solidifying the printed wiring board or the printed circuit board. The entire surface of the printed circuit board or the printed circuit board is transferred from a nozzle for heating hot air that is disposed in a vertical direction of the printed circuit board or the printed circuit board inside the reflow furnace. overall the printed wiring board or the printed circuit board by hot air ejected in a range including Serial is heated to a temperature above the melting point of the provision of the solder material, the after again melt the solder of the solder joints of the soldered the insertion type electronic component, wherein said printed wiring board at a temperature higher than the melting point of the provision, or The printed circuit board is uniformly heated and held, and the printed circuit board or the printed circuit board is cooled from a cooling-jet nozzle for cooling disposed in the vertical direction of the printed circuit board or the printed circuit board inside the reflow furnace. The printed wiring board or the entire printed circuit board, which is uniformly heated and held by the refrigerant sprayed over a range including the entire surface, is cooled at the same time, and the re-melted solder is solidified. Or a printed circuit board soldering method.

According to the method of soldering a printed wiring board or a printed circuit board according to the first aspect of the present invention, a printed wiring board or a printed circuit mounting board on which electronic components once soldered are mounted is conveyed and inserted into a reflow furnace, By blowing hot air from the upper and lower nozzles, the entire printed wiring board or printed circuit mounting board is heated again uniformly all at once, and the solder joint portion of the electronic component is heated and melted again. The entire printed wiring board or printed circuit board is held uniformly at that temperature, the solder remains in a molten state, and the entire printed wiring board or printed circuit board is made uniform by the coolant jet cooling from the upper and lower nozzles. Since it is cooled, the remelted solder in the solder joint is solidified uniformly regardless of the mounting position. By uniformly cooling the solder joints, the occurrence of lift-off and shrinkage can be reduced, and the fatigue resistance can shorten the crack length after the fatigue test. The effect that it is excellent is acquired. Moreover, since the re-melted solder is rapidly cooled by using the rapid cooling medium, it becomes a solidified solder having a fine metal structure, so that soldering excellent in fatigue resistance can be obtained.

The printed wiring board or printed circuit board soldering method according to the second aspect of the present invention is a lead-free solder material for a printed circuit board on which a printed wiring board or surface-mounted component is mounted using a conveyor type soldering apparatus. In the soldering method according to the above, when the printed wiring board or the printed circuit board on which the lead terminal is inserted into the through hole and the insertion type electronic component is mounted, before the soldered solder is solidified, The printed wiring board or the printed circuit board is transported and charged into a reflow furnace, and the printed circuit board or the printed circuit board inside the reflow furnace is heated from the nozzle for heating hot air arranged in the vertical direction of the printed circuit board. Hot air blown over a range including the entire surface of the wiring board or the printed circuit board or the reflow The printed circuit by refrigerant from the refrigerant ejection nozzle of the deployed cooling vertically ejected to a range including the entire surface of the printed wiring board or the printed circuit board inside of the printed wiring board or the printed circuit board The board or the printed circuit board is heated or cooled until it reaches a temperature equal to or higher than a specified melting point, and the entire printed wiring board or the printed circuit board uniformly heated and held at a temperature equal to or higher than the specified melting point is simultaneously cooled. A method of soldering a printed wiring board or a printed circuit board, characterized in that molten solder is solidified.

According to the method of soldering a printed wiring board or a printed circuit board according to the second aspect of the present invention, before the soldered solder is solidified, it is conveyed and inserted into a reflow furnace, and hot air or a refrigerant is ejected from the upper and lower nozzles. The entire printed wiring board or printed circuit mounting board is heated or cooled uniformly to a temperature equal to or higher than the specified melting point, and the entire printed wiring board or printed circuit mounting board is uniformly heated and held at that temperature, Since the entire printed wiring board or printed circuit board is uniformly cooled by jetting and cooling of the refrigerant from the upper and lower nozzles while the solder is still in a molten state, the remelted solder The solder at the joint is solidified uniformly regardless of the mounting position. By uniformly cooling the solder joints, the occurrence of lift-off and shrinkage can be reduced, and the fatigue resistance can shorten the crack length after the fatigue test. The effect that it is excellent is acquired. In addition, since the time for remelting the solder at the solder joint portion once solidified is shortened, the soldering workability is improved. Moreover, since the re-melted solder is rapidly cooled by using the rapid cooling medium, it becomes a solidified solder having a fine metal structure, so that soldering excellent in fatigue resistance can be obtained.

The conveyor type soldering apparatus according to the first aspect of the present invention is a conveyor type soldering apparatus used in the above-described printed wiring board or printed circuit board soldering method according to the first or second aspect of the present invention. a is a flow reactor composed of pre-heating unit and a solder bath, and a reflow furnace cooling portion and connected to said rear portion of the flow furnace heating portion is integrally formed, said same flow reactor and the reflow furnace A conveyor arranged on a line; a sensor for detecting a position of a soldering substrate conveyed on the conveyor; a detection unit for reading position data from a signal of the sensor; and the printed wiring board or the surface-mounted component. Heating and cooling of the flow furnace and the reflow furnace according to position data from the detection unit of the printed circuit board mounted with the conveyor And a controller for controlling the speed, the reflow furnace, the the said printed circuit board is conveyed charged into a reflow furnace or a printed circuit board, wherein the surface mount components are mounted, in order to uniformly heat In accordance with a request from the controller, there is a hot air jet nozzle for heating arranged in the reflow furnace and a cooling refrigerant jet nozzle arranged in the reflow furnace for uniform cooling. In addition, it is possible to instantaneously switch between heating and cooling by ejecting hot air for heating from the nozzle for ejecting hot air, or ejecting a cooling refrigerant from the nozzle for ejecting refrigerant. Device.

According to the conveyor type soldering apparatus according to the first aspect of the present invention, since the reflow furnace is integrally provided with the heating part and the cooling part, the entire substrate can be heated or cooled, and the solder joint part is uniform. Since the solder in the solder joints is uniformly solidified by cooling, the occurrence of lift-off and shrinkage is reduced, and the fatigue resistance can shorten the crack length after the fatigue test, and the soldering quality The effect that soldering with excellent fatigue resistance can be obtained is obtained. Moreover, the reflow furnace is provided in the rear part of the flow furnace on the same line, and there exists an advantage that handling of a conveyor type soldering apparatus is easy. Further, the reflow furnace is provided with a hot air jet nozzle for heating to uniformly heat and a coolant jet nozzle for cooling to uniformly cool, so that the entire substrate can be heated or cooled. By uniformly cooling the solder joints, the occurrence of lift-off and shrinkage can be reduced, and the fatigue resistance can shorten the crack length after the fatigue test, and there is little variation in soldering quality. The effect that the soldering which was excellent in can be obtained.

The conveyor type soldering apparatus according to the second aspect of the present invention is a conveyor type soldering apparatus used in the method for soldering a printed wiring board or a printed circuit board according to the first or second aspect of the present invention. a is a flow reactor composed of pre-heating unit and a solder bath, cooling unit and connected to said rear portion of the flow furnace heating unit and a reflow furnace which is integrally formed, of the flow reactor and before Symbol reflow oven A conveyor branch section that branches the transfer line into two or more in the middle, a first conveyor including the conveyor branch section, a branched second conveyor, and another reflow furnace connected to the second conveyor; , A sensor for detecting the position of the printed wiring board or the printed circuit board conveyed on the first and second conveyors, and position data from the signal of the sensor The flow furnace and the two or more reflow furnaces are heated and cooled according to the position data from the detection part to be read, and the printed circuit board on which the printed wiring board or the surface-mounted component is mounted. And a controller for controlling sorting of the printed wiring board or the printed circuit board on which the surface mount component is mounted, the flow soldering at the branch portion being finished, and the reflow furnace is disposed in the reflow furnace. In order to uniformly heat the printed circuit board loaded with the printed wiring board or the surface-mounted component, the hot air jet nozzle for heating disposed in the reflow furnace is uniformly cooled. In order to meet the demand from the controller, the cooling jet nozzle for cooling disposed in the reflow furnace is provided. Te, ejecting hot air for heating from the hot air nozzle, or a coolant for cooling conveyor type solder and this and characteristics can be switched heating and instantaneously cooled by ejected from the refrigerant ejection nozzle Attachment device.

According to the conveyor-type soldering apparatus according to the second aspect of the present invention, a conveyor branch section that branches the conveyance line into two or more is provided, and the soldered mounting board discharged from the flow furnace at a constant speed is provided. By branching and transporting to the reflow furnace, the interval for inserting the printed wiring board to be reflow-soldered or the printed circuit board with surface-mounted components into the flow furnace can be shortened, and the work efficiency of soldering can be increased. There is an effect. Further, the reflow furnace is provided with a hot air jet nozzle for heating to uniformly heat and a coolant jet nozzle for cooling to uniformly cool, so that the entire substrate can be heated or cooled. By uniformly cooling the solder joints, the occurrence of lift-off and shrinkage can be reduced, and the fatigue resistance can shorten the crack length after the fatigue test, and there is little variation in soldering quality. The effect that the soldering which was excellent in can be obtained.

The printed wiring board or printed circuit board soldering method according to the third aspect of the present invention is the above-described printed wiring board or printed circuit board soldering method according to the first or second aspect of the present invention. Soldering of printed circuit boards or printed circuit boards characterized in that the temperature above the specified melting point is within the temperature range of the melting point of the solder material + 5 ° C or higher and the heat resistant temperature of the electronic component to be soldered-5 ° C or lower. Is the method.

According to the soldering method of the printed wiring board or the printed circuit board according to the third aspect of the present invention, the soldered electrons are maintained by maintaining the ambient temperature at the minimum temperature at which the solder material can be maintained in a molten state. Deterioration of the function of the parts can be prevented, and since the temperature difference between the melting temperature and the solidification temperature is small, uniform rapid cooling and solidification can be achieved, so that the occurrence of lift-off and shrinkage can be reduced.

The printed wiring board or the printed circuit board according to the fourth aspect of the present invention is soldered to the printed wiring board or the printed circuit board according to any one of the first to third aspects of the present invention. In the method, the lead-free solder material is Sn—Cu, Sn—Ag, Sn—Ag—Cu, Sn—Ag—Cu—Bi, Sn—Ag—Cu—Sb, which is a basic solder material mainly composed of Sn. Sn-Ag-Bi-In, Sn-Ag-In, Sn-Zn, Sn-Zn-Bi, Sn-Sb, and the basic solder materials include Al, Si, P, S, Ti, V, Cr , Mn, Fe, Co, Ni, Ga, Ge, As, Se, Zr, Nb, Mo, Pd, Hf, Ta, W, Pt, and any one selected from lead-free solder materials to which trace amounts of Au are added Is the material of A method of soldering a printed wiring board or a printed circuit board .

According to the method for soldering a printed wiring board or a printed circuit board according to the fourth aspect of the present invention , lead-free solder can be used, so that the produced printed circuit board does not adversely affect the environment. .

  According to the soldering method of the present invention, when reflow soldering a flow soldered mounting board, the solidified solder joint of the flow soldering is remelted at a specified temperature, or a solder joint in a molten state Is effectively heated to the specified temperature and rapidly cooled from a state where the entire surface of the mounting board is uniformly heated and held, so that the melted solder in the solder joint is uniformly solidified to effectively reduce the occurrence of lift-off. Can do. In addition, the metal structure of the rapidly-cooled and solidified solder joint can be refined to improve the mechanical strength of the solder joint and reduce the variation in fatigue life.

  Further, the soldering apparatus of the present invention is a reflow which rapidly cools and solidifies from a state of being uniformly heated and held after re-melting the solder joint portion of the printed circuit mounting board subjected to flow soldering at the rear portion of the flow soldering portion. By providing the soldering portion and reflow soldering the flow soldered mounting substrate, it is possible to reduce lift-off occurrence and fatigue life variation.

  By applying the soldering method and / or the soldering apparatus, the quality and reliability of the printed circuit mounting board can be improved.

  Hereinafter, the soldering method in the present invention will be described with reference to the drawings.

  FIG. 4 is a flowchart of a conventional flow soldering method, illustrating a conventional flow soldering process 30 for a printed wiring board using a conveyor type flow soldering apparatus.

Circuit wiring such as copper lands and copper through holes for soldering electronic components is provided to prepare a printed wiring board for double-sided mounting (step 31). Insertion type electronic components are mounted by inserting lead terminals of electronic components of insertion package type (hereinafter referred to as insertion type), for example, electronic components such as relays, capacitors, resistors, etc., into the specified through holes of the double-sided printed wiring board. (Step 32). A printed wiring board (hereinafter referred to as a component mounting board) on which insertion type electronic components are mounted is set on a conveyor, conveyed, and inserted into a flow furnace (step 33). First, in the flux application process 34, the soldering flux is uniformly applied to the soldering surface of the component mounting board. In component mounting substrate preheating step 35 the coating of the flux is completed, the flux was activated are preheating the preheating temperature for improving solderability, is a belt conveyor to the flow soldering attachment process 36. Lead-free solder, for example, Sn-Ag-Cu-based lead-free solder is melted (250 ° C) in a jet-type solder bath and soldered between the lead terminal of the insertion type electronic component on which the component mounting board is mounted and the copper land Flow soldering is performed (step 36). The component mounting board to which the solder is adhered is cooled and solidified (step 37), and is taken out and taken out from the flow furnace (step 38). The component mounting board (hereinafter referred to as the mounting board) on which the solder joint is formed after the flow soldering is finished is subjected to post-processing such as cleaning and removing the attached solder flux, An appearance inspection (step 39) is performed, and a mounting substrate (hereinafter referred to as a flow processing mounting substrate 50f) on which insertion type electronic components are mounted by a flow furnace is manufactured.

  FIG. 5 is a flowchart of a conventional reflow soldering method, and illustrates a conventional printed circuit board reflow soldering process 40 using a conveyor type reflow soldering apparatus.

  A printed wiring board on which the surface-mounted components to be soldered are loaded is placed in a reflow furnace (step 41). In the reflow furnace, the printed wiring board on which the surface mounting components are mounted by the atmospheric gas for heating or infrared radiation while being conveyed by the conveyor is heated, and when the melting temperature is reached, the applied solder paste or solder plating is melted (step 42). ). When heated and melted for a certain period of time, it is conveyed to a cooling zone, and a cooling gas is ejected from a nozzle in the reflow furnace, the printed wiring board on which the surface mounting components are mounted is cooled, and the molten solder is solidified (step 43). . After the reflow soldering is finished, the printed circuit board on which the surface mounting components are soldered is discharged from the reflow furnace (step 44). After the reflow soldering, the component mounting board is subjected to post-processing such as cleaning. The appearance inspection of reflow soldering is performed (step 45), and the process proceeds to the next step.

  Next, the soldering method according to the first embodiment of the present invention and the soldering apparatus according to the first embodiment will be described with reference to FIGS. FIG. 1 is a flowchart of a soldering method according to the first embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a soldering apparatus according to the first embodiment of the present invention.

In FIG. 2, the conveyor type soldering apparatus 1 according to the first embodiment of the present invention includes a fluxer 101 for applying flux to the solder surface of a printed wiring board on which electronic components are mounted, and preheating for preheating the printed wiring board. A flow furnace 100 composed of a unit 102, a solder bath 103, for example, a jet type solder bath, and a cooling section 104; a solder remelting / uniform heating section 111 and a rapid cooling section 112 connected to the rear portion of the flow furnace 100; A reflow furnace 110 configured integrally, a conveyor 105 disposed on the same line of the flow furnace 100 and the reflow furnace 110, and a plurality of sensors 107 for detecting the position of a printed wiring board conveyed on the conveyor 105. A detection unit 106 that reads position data from the signal of the sensor 107, and a printed wiring from the detection unit 106 The position data consists of a controller 108 which controls the speed of cooling and the conveyor and heating the flow furnace 100 and a reflow furnace 110.

The printed wiring board soldering method of the present invention using the conveyor type soldering apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. The conveyor type soldering apparatus 1 in the 1st form of this invention is comprised from the flow furnace 100 and the reflow furnace 110 so that it may become clear from the schematic block diagram of FIG. Although the reflow furnace 110 is a conveyor type, it is not the zone heating and zone cooling of the conventional conveyor type reflow furnace, but the entire reflow furnace is integrally heated and cooled, and is switched to cooling. FIG. 1A is a flowchart of the soldering method 10a of the present invention, which is the same as the soldering process 30 of the conventional flow furnace, but the steps of the reflow furnace (steps 18 to 21) are the solder of the conventional reflow furnace. This is different from the attaching step 40.

  The soldering method 10a according to the first embodiment of the present invention is the mounting in which the component mounting board is flow soldered in the flow furnace 100 and then continuously soldered in the reflow furnace 110 in the conveyor type soldering apparatus 1. Reflow soldering is performed to remelt and solidify the solder at the solder joint of the board. Note that the reflow soldering referred to here is not a general solder plating or solder paste that has been applied in advance, but soldering the mounted components, and soldering the lead terminals and printed wiring of the mounted components. This refers to remelting and solidifying the solder at the solder joint with the copper land of the plate.

  Circuit wiring such as copper lands and copper through-holes for soldering electronic components is provided, and a printed wiring board for double-side mounting is prepared in which a solder resist is applied except for the soldering portion (step 11). The printed wiring board for mounting may be either a single-sided board or a double-sided board. In the first embodiment of the present invention, an insertion component is mounted on the printed wiring board by flow soldering, but before the flow soldering. The surface mount component may be mounted by reflow soldering. As an insulating base material for the printed wiring board, a glass epoxy substrate or a metal core substrate can be used. Furthermore, a multilayer printed wiring board can also be used. Next, lead terminals of insertion-type electronic components, for example, electronic components such as relays, capacitors, resistors, etc., are inserted into prescribed through holes, and the electronic components are mounted (step 12). The printed wiring board (component mounting board 50a) on which electronic components are mounted is set on the conveyor 105, conveyed to the conveyor, and inserted into the flow furnace 100 (step 13). The mounting of the component mounting board 50a is detected by the sensor 107b and sent to the control unit 108 via the detection unit 106, and the soldering operation of the soldering apparatus 1 is started. In this description, the sensor 107 is provided at the entrance / exit of the soldering apparatus 1, but is appropriately arranged as necessary.

  First, flux for soldering is uniformly applied to the soldering surface of the component mounting board 50a by the fluxer 101 (step 14). The component mounting board 50a after the application of the flux is preheated by a preheating unit 102 to a preheating temperature for soldering, for example, 150 to 170 ° C. (step 15). In the flow solder attaching step 16, lead-free solder, for example, Sn-Ag-Cu-based lead-free solder is melted (250 ° C) in a jet-type solder bath 103 by jet solder between the inserted component terminal of the component mounting board and the copper land. Flow solder adhesion is made. In addition, as a lead free solder, the lead free solder which has Sn as a main component, Preferably, Sn-Ag, Sn-Cu, Sn-Ag-Cu, Sn-Ag-Cu-Bi, Sn-Ag-Cu-Sb, Sn-Ag-Bi-In, Sn-Ag-In, Sn-Zn, Sn-Zn-Bi, Sn-Sb, and the above-mentioned alloys include Al, Si, P, S, Ti, V, Cr, Mn Fe, Co, Ni, Ga, Ge, As, Se, Zr, Nb, Mo, Pd, Hf, Ta, W, Pt, and Au may be added in minute amounts.

  The component mounting board 50a to which the solder is attached is cooled to below the freezing point by the cooling unit 104, and the molten solder is solidified. The cooling method may be natural cooling, or may be cooled by immersion in a refrigerant liquid adjusted to a temperature selected in advance, or by spraying the refrigerant by gas injection, spraying, or showering. As a coolant for cooling the mounting board, air, water vapor, water, liquefied carbon dioxide (gas), liquefied nitrogen (gas), liquefied argon (gas), gas or liquid lower than the melting point of the solder material used, Liquefied helium (gas) can be used.

  The component mounting board (flow processing mounting board 50f) on which the soldering portion is formed after the flow soldering is completed is discharged from the flow furnace 100 while being further cooled (step 17a). The flow processing mounting substrate 50f is charged into the reflow furnace 110 having a forced cooling mechanism while being cooled by the conveyor 105 (step 18a).

  FIG. 6A is a schematic diagram of the conveyor-type reflow furnace 110, and FIG. 6B is a schematic diagram showing a vertical cross-sectional structure of the reflow furnace 110 and a soldering state of the flow processing mounting board 50f. In addition, the conveyor is abbreviate | omitted in Fig.6 (a) and FIG.6 (b). 6B shows a heating state of the flow processing mounting board 50f by a hot air heating method and a cooling state by a refrigerant. A heating nozzle 115 for heating and cooling are provided in the vertical direction of the flow processing mounting board 50f. A cooling nozzle 116 is disposed. The flow processing mounting board 50f is heated by hot air gas 115a ejected from the heating nozzle 115, for example, nitrogen gas preheated to a predetermined temperature by passing nitrogen gas through a space in which a heater (not shown) is installed, and ambient gas. Heated uniformly. The temperature of the heated gas varies depending on the solder material used and the heat resistance of the component. For example, in the case of lead-free solder material Sn-3.0Ag-0.5Cu (melting point: about 217 ° C.), the soldering temperature 250 for flow soldering is used. It is heated to about 230 ° C., which is below the temperature.

  As shown in FIG. 6B, the flow processing mounting board 50f is heated at a predetermined temperature, and the solder joint portion 55 (the lead terminal 52a of the electronic component, the copper land 53, the copper through hole) of the wiring board 51 is heated. 54 and the solder)), the solidified solder is melted.

  The atmosphere temperature in the furnace at the time of remelting heating is higher than the melting point of the solder material, for example, the melting point of the solder + 5 ° C. or higher, and the heat resistant temperature of the parts −5 ° C. or lower. Hot air 115a having an atmospheric temperature injected from 115 is injected into the furnace, the atmospheric temperature in the furnace rises, and is obtained by reaching the temperature of the hot air 115a (atmospheric temperature). It is desirable that the holding time at the time of remelting the solder is a short time during which the copper erosion of the copper land is difficult to progress and the printed circuit board 50 and the mounted electronic components are not damaged by heat.

Reflow furnace flow process mounting substrate 50f which is charged to 110, in the solder melting and uniform heating unit 111 is heated to a predetermined temperature, solidified solder of the solder joint is molten. Further, while the belt is transported in the reflow furnace 110, the entire surface of the flow processing mounting substrate 50f is heated and held uniformly (step 19a).
The heating method of the reflow furnace may be either a hot air heating method or an infrared radiation heating method, or may be a heating method that combines both heating methods, as long as it can quickly respond to switching between heating and cooling.

  The reflow furnace 110 only needs to have a mechanism capable of uniformly heating one or a plurality of mounting boards 50 conveyed by a belt and uniformly cooling them simultaneously. The atmosphere in the reflow furnace may be air, but a nitrogen atmosphere is usually applied to prevent oxidation of solder, component lead terminals, and the like.

  In the rapid cooling section 112, when a certain time has elapsed, rapid cooling is started from a state in which the entire surface of the flow processing mounting board 50f is uniformly heated and held, and the entire surface of the flow processing mounting board 50f is uniformly cooled below the melting point. (Step 20).

  In the cooling method, a coolant 116a cooled to at least room temperature or less, for example, a cooled nitrogen gas cooled to a predetermined temperature through a cooling device (not shown) is ejected from the cooling nozzle 116 within a range where the mounting substrate does not move by the ejection gas pressure. Rapid cooling is provided by spraying or showering. When supplying the coolant, the supply of the hot air 115a is stopped, the flow processing mounting board 50 is cooled, and the solder of the solder joint portion 55 is solidified. The cooling nozzles 116 and the like are installed in the vertical direction of the reflow furnace 110, and the heating nozzles 115 and the cooling nozzles 116 are alternately arranged in a grid pattern. The pipes connected to the nozzles 115 and 116 are desirably two pipes for cooling and heating. Further, simultaneously with cooling, the internal heating atmosphere gas can be removed by an exhaust device (not shown) to accelerate the cooling. It is desirable that the cooling rate of the flow processing mounting substrate 50 be 10 ° C./second or more, and the average cooling rate is 10 to 20 ° C. from the temperature at which the solder is melted to the temperature range approximately 40 ° C. lower than the freezing point. Optimum results can be obtained by setting to 1 / sec.

  The necessary cooling rate can be obtained by controlling the temperature of the refrigerant and the ejection amount, but the cooling rate also varies depending on the substrate specifications and the ambient temperature of the reflow furnace 110 during heating. For this reason, when actually applied, a thermocouple is first attached to the solder joint by a preliminary test, and heating / cooling (remelting / solidification treatment) is performed under predetermined conditions. Soldering inspection of the heated / cooled flow processing mounting board 50 is performed, and the heating / cooling conditions are confirmed. After optimal heating / cooling conditions are obtained, actual soldering work (heating and cooling the flow-soldered mounting board is performed again) is performed under those conditions.

  The reflow-processed mounting board 50r that has been cooled in the reflow furnace 110 is unloaded from the reflow furnace 110 and the reflow soldering that has been taken out is not a non-cleaning type flux. After the post-treatment such as cleaning and removal, an appearance inspection (step 22) of the solder joint is performed.

  As described above, the reflow processing mounting substrate 50r is manufactured by the soldering method according to the first embodiment of the present invention in which a series of flow soldering-reflow soldering is performed.

  In the above description, the printed wiring board on which the insertion type electronic component is mounted has been described. However, the soldering according to the first embodiment of the present invention is performed on the printed circuit board on which the surface mounting component is mounted (soldered). It may be a case where electronic components are mounted. For mounting substrates on which surface mounted components that have low heat resistance or whose characteristics deteriorate due to rapid cooling are mounted, heating prevention or protection is required to protect those electronic components. In order to prevent rapid cooling, it can be applied after pretreatment such as covering with a pallet. In addition, surface mount components that are reflow soldered with the same solder paste as the lead-free solder used for soldering insertion type mount components will melt the solder joints by heating, but surface mount components are heat resistant. Since the surface mounting component is not peeled off or moved by the remelting process, the soldering method according to the first embodiment of the present invention can be applied.

  The soldering method 10a in the first embodiment of the present invention described above is transferred from the flow furnace 100 to the reflow furnace in a state where the solder in the solder joint is solidified, whereas in the second embodiment of the present invention. When the soldering method 10b is conveyed from the flow furnace 100 to the reflow furnace 110, the solder adhered in the flow solder tank is sent to the reflow furnace 110 in a molten state.

  The soldering method 10b in the 2nd form of this invention is demonstrated. After passing through the same soldering process as the first embodiment (processes 11 to 15), the component mounting board 50a is conveyed to the solder bath 103 by the conveyor 105 and soldered (process 16). The component mounting board 50b is transferred to the reflow furnace 110 that has been heated to a predetermined temperature in a state where the molten state is maintained (step 17b) without the solder adhering to the solder joint being solidified by the cooling unit 104. (Step 18b). In the reflow furnace 110, the solder is rapidly cooled from the uniformly heated state (step 19b), and the solder in the solder joint is solidified (step 20). The reflow-processed mounting board 50r that has been cooled in the reflow furnace 110 is unloaded from the reflow furnace 110 and the reflow soldering that has been taken out is not a non-cleaning type flux. After the post-treatment such as cleaning and removal, an appearance inspection (step 22) of the solder joint is performed.

  FIG. 3 is a schematic configuration diagram of the soldering apparatus 2 according to the second embodiment of the present invention. In addition, the code | symbol is attached | subjected to the structure which has the same function as FIG. In FIG. 3, the conveyor type soldering apparatus 2 according to the second embodiment of the present invention includes a flow furnace 100, a solder reflow furnace 110 connected to the rear part of the flow furnace 100, and the middle of the flow furnace 100 and the reflow furnace. A conveyor branch unit 109 that branches the transport line into two or more, a first conveyor 105a including the conveyor branch unit 109, a branched second conveyor 105b, and a reflow furnace 120 connected to the second conveyor 105a; , A sensor 107 for detecting the position of the component mounting board or mounting board conveyed on the first and second conveyors, a detection unit 106 for reading position data from the signal of the sensor 107, and component mounting from the detection unit 106 The heating and cooling of the flow furnace 100 and the two reflow furnaces 110 and 120 and the first co And a conveyor speed of bare 105a and a second conveyor 105b, and a controller for controlling the sorting of a flow substrate 50f in the branch unit 109.

  Next, the effect of the soldering method of the present invention on the solder joint will be specifically described with reference to examples.

  In the conventional flow furnace soldering, the solder that has been rapidly cooled and solidified after the flow soldering and the conveyor type soldering apparatus 1 according to the first embodiment of the present invention are used to re-solder the solder joints after the flow soldering. Using a sample prepared by rapid cooling and solidification after melting, a comparison test between the conventional technology and this example was conducted on the effect and effect of soldering method (rapid cooling) on the generation of shrinkage nests and lift-off in solder joints. It was.

  FIG. 9 shows a schematic diagram of a printed wiring board 70 on which test electronic components are mounted. The printed wiring board 71 was a single-sided glass epoxy board (thickness: 1 mm, size: 150 mm square) provided with a copper land width of 0.5 mm and a copper through hole diameter of φ1.4 mm. Nine printed circuit board relays 72 (manufactured by OMRON: G8FE-1AP-L) were used as electronic components mounted on the printed wiring board 71. The material of the lead terminals of the relay 72 is copper, and the number of lead terminals is six / piece. The relay 72 is mounted on the board front part 71f, on the board center part 71c, on the board rear part 71r, and on the board rear part 71r with the transport direction (indicated by the arrow 75 in FIG. 4) of the flow soldering wiring board 71 as a reference. Three were installed. Six boards 70 on which relays 72 are mounted are prepared, and six sheets are subjected to rapid cooling flow soldering using a conventional flow furnace under the following conditions, three of which are used as soldering samples of the prior art. (Sample Nos. 1a to 3a). Using the conveyor type soldering apparatus provided with the rapid cooling mechanism for the remaining three sheets, reflow soldering was performed for rapid cooling after remelting the solder joints under the following conditions of this example (Sample No. 1b to No. 1b). 3b). As the solder material, lead-free Sn-3.0Ag-0.5Cu (melting point: about 217 ° C.) was used.

Conventional soldering method Flow soldering conditions: Conveyance speed: 1 m / min,
Solder jet temperature: 250 ° C.

Cooling speed: 10 ° C./second Soldering method of this example Flow soldering conditions: Conveying speed: 1 m / min
Solder jet temperature: 250 ° C.

Cooling rate: 10 ° C./second Reflow soldering conditions: Conveying speed: 1 m / min
Heating rate: 10 ° C / second
Atmospheric temperature: 230 ° C Heating time: 30 seconds
Cooling rate: 10 ° C / second

Surface observation (magnification is 30 to 200) using a scanning electron microscope (SEM) of solder joint portions (see FIG. 6 (b) 53) of the lead terminals of each relay in the sample (mounting substrate) manufactured under the above soldering conditions Inspect the state of occurrence of the shrinkage nest and the lift-off state by using a suitable double), and then perform a cross-sectional inspection on the part that is considered to be lift-off by surface observation to confirm the lift-off, whereby the front part 71f, the central part 71m, and the rear part The number of shrinkage nests and the number of liftoffs for each 71r were determined. The number of shrinkage cavities and the number of liftoff occurrences indicate the number of solder joints of the lead terminal where shrinkage cavities and liftoff are generated in the solder joints. The obtained results are shown in Table 1.

表1より、引け巣の発生数に関しては、各試料の検査はんだ接合部５４ヶ所で３試料の全検査はんだ接合部１６２ヶ所において、従来技術のはんだ付け方法の引け巣発生数は、３試料合計で４８ヶ所に対して、本発明の実施例１のはんだ付け方法の引け巣発生数は、３試料合計で４ヶ所と従来技術のはんだ付け方法の８％と非常に少なく、コンベア式はんだ付け装置によりフローはんだ付けした実装基板のはんだ接合部のはんだを再溶融して冷却凝固する本発明の実施例１のはんだ付け方法の効果が認められる。また、電子部品の搭載位置による影響は、各搭載位置の各試料の検査はんだ接合部は１８箇所で３試料の全検査はんだ接合部５４ヶ所において、従来技術のはんだ付け方法における各部の引け巣発生数は、基板前部は合計１１ヶ所、基板中央部は合計１３ヶ所、基板後部は２４ヶ所である。最後に冷却される基板後部の発生数は他の位置の約２倍であり、電子部品の搭載位置によって引け巣の発生数にばらつきが生じている。これは従来技術のはんだ付け方法では、フローはんだ付けライン上を搬送しながら溶融はんだは冷却されて、基板前部、基板中央部、基板後部では、加熱温度、冷却速度等のはんだ付け条件が異なるためと考えられる。

From Table 1, regarding the number of shrinkage nests generated, the number of shrinkage nests generated by the soldering method of the prior art is the total of 3 samples at 54 test solder joints for each sample and 162 test solder joints for all 3 samples. In contrast, the number of shrinkage cavities generated by the soldering method of Example 1 of the present invention is very small at 4 places in total of 3 samples, 8% of the soldering method of the prior art, and the conveyor type soldering apparatus. The effect of the soldering method of Example 1 of the present invention in which the solder at the solder joint portion of the mounting substrate that has been flow soldered is remelted and cooled and solidified is recognized. In addition, the influence of the mounting position of the electronic component is that the test solder joints of each sample at each mounting position are 18 places, and all the test solder joint parts of three samples are generated at 54 places in the soldering method of the prior art. The total number of the front part of the board is 11 places, the central part of the board is 13 places in total, and the rear part of the board is 24 places. The number of occurrences of the rear part of the substrate that is finally cooled is about twice that of the other positions, and the number of shrinkage nests varies depending on the mounting position of the electronic component. In the conventional soldering method, the molten solder is cooled while being conveyed on the flow soldering line, and the soldering conditions such as the heating temperature and the cooling rate are different at the front part of the board, the central part of the board, and the rear part of the board. This is probably because of this.

  In the soldering method of Example 1 of the present invention, the number of shrinkage nests at each mounting position is the above-mentioned number of inspections, the board front part is a total of one place, the board center part is a total of one place, the board rear part is two places, The rear part of the substrate tends to be larger than the others, but the number of occurrences is very small, and it cannot be said that there is an influence of the mounting position on the number of shrinkage nests. The reason for this is that in the soldering method according to the first embodiment of the present invention, the flow-treated substrate is conveyed by the belt, but is uniformly heated at the remelting temperature, and at each position of the substrate front, substrate central, and substrate rear. Because the entire board with no temperature difference is quickly and uniformly cooled, the positional relationship between the front part of the board, the central part of the board, and the rear part of the board is almost eliminated, and the variation in cooling speed is small, so the number of shrinkage nests is considered to be It is done.

  As described above, in the case of the conventional soldering method, the temperature change due to the time difference in which the substrate position (front, center, rear) is transferred to the cooling position due to the substrate being cooled while being conveyed on the line, etc. The molten state of the solder adhering to the board is kept constant until immediately before quenching, depending on the temperature of the solder, the transfer speed of the board, the distance from the flow solder bath to the rapid cooling, the ambient temperature, etc. Therefore, the soldering quality of the mounting substrate that has been rapidly solidified due to variations in the cooling rate or the like varies.

  On the other hand, in the case of the soldering method according to the first embodiment of the present invention, the substrate is transported on the line, but the mounting substrate subjected to flow soldering is heated by the reflow furnace so that the entire substrate is heated and uniformly held. The solder at the joint is re-melted and uniformly heated and held. Since the entire substrate is rapidly cooled from the uniformly heated and held solder molten state and the solder in the solder joint is solidified, stable and good soldering quality can be obtained.

  Regarding the number of lift-off occurrences, the number of lift-off occurrences was zero for both the prior art soldering and the soldering of Example 1 of the present invention, no lift-off occurred, and there was no difference depending on the soldering method. From this, it was confirmed that the soldering method of Example 1 of the present invention has a sufficient effect of suppressing the occurrence of lift-off.

  In the same manner as in Example 1, in the conventional flow furnace soldering, the sample subjected to rapid cooling and solidification after the flow soldering, and the solder bonding after the flow soldering of the first embodiment of the present invention using the conveyor type soldering apparatus A comparison test between the conventional technology and this example was conducted on the effects and effects of the soldering method (rapid cooling) on the fatigue life of the soldered joint using a sample prepared by remelting and rapidly cooling and solidifying the part. It was.

  In addition, the printed wiring board 70 and the mounting component 72 used the same thing as Example 1, and soldered on the same soldering conditions. Sample No. Since the soldering conditions were the same as in Example 1, the same numbers were assigned.

  The manufactured comparative test sample was placed in a thermostatic chamber capable of automatic temperature control, and a fatigue test was performed. The fatigue test is a cycle test with a temperature change from −40 ° C. to 140 ° C. The temperature profile in the thermostatic bath is maintained at −40 ° C. for 30 minutes → increased to 140 ° C. over 30 minutes → held at 140 ° C. for 30 minutes → decreased to −40 ° C. over 30 minutes. A 1000 cycle fatigue test was conducted.

  After completion of the fatigue test, a cross-sectional observation (a magnification of 30 to 200 times is used as appropriate) of each solder joint portion of the sample (mounting substrate to be tested) using a scanning electron microscope (SEM) is performed. The crack length was measured. Average values of the crack lengths of the measured substrate front portion 71f, substrate center portion 72m, and substrate rear portion 71r were derived. A sample in which a long crack is detected is a mounting substrate having a short life. Table 2 shows the results of the obtained solder crack length.

表２より、従来技術のはんだ付け方法によるはんだき裂長さ（全平均値６６９μｍ）よりも、本発明の実施例２のはんだ付け方法のはんだき裂長さ（全平均値４５８μｍ）は、約２１０μｍ小さくなっている。また、従来技術のはんだ付け方法における各部品搭載位置の平均はんだき裂長さは、基板前部７１ｆは６１７μｍ、基板中央部７１ｍは６２７μｍ、基板後部７１ｒは７６４μｍであり、最後に冷却される基板後部７１ｒのはんだき裂長さは他の位置７１ｆ、７１ｍよりの約１５０μｍ長く、電子部品の搭載位置によってはんだき裂長さに差異（ばらつき）が生じている。

From Table 2, the solder crack length (total average value 458 μm) of the soldering method of Example 2 of the present invention is about 210 μm smaller than the solder crack length (total average value 669 μm) of the conventional soldering method. It has become. In addition, the average solder crack length at each component mounting position in the soldering method of the prior art is 617 μm for the substrate front portion 71 f, 627 μm for the substrate center portion 71 m, and 764 μm for the substrate rear portion 71 r, and finally the substrate rear portion to be cooled The solder crack length of 71r is about 150 μm longer than the other positions 71f and 71m, and a difference (variation) occurs in the solder crack length depending on the mounting position of the electronic component.

    This is the conventional soldering method, where the component mounting board is soldered in a jet solder bath, and then the mounting board is cooled while being conveyed on the flow soldering line (front, center, rear) Is cooled according to the temperature change due to the time difference that is transferred to the cooling position, the temperature of the jet solder, the substrate transfer speed, the distance from the flow solder bath to the rapid cooling, the ambient temperature, etc., and the mounting position (front portion 71f) The central part 71m and the rear part 71r) have different conditions before the rapid solidification. Therefore, the size of the Sn crystal grains in the solder solidified structure of the solder joint is different, and variation occurs in the solder crack length (life).

    In the soldering method of Example 2 of the present invention, the average solder crack length at the component placement position is 443 μm at the front part 71f of the substrate, 450 μm at the central part 71m of the board, and 480 μm at the rear part 71r of the board. The variation in length is as small as 40 μm, and the influence of the mounting position is not so much. Also, the solder crack length of the prior art soldering is smaller by about 170 μm at the board front part 71f and the board central part 71m and by about 280 μm at the board rear part 71r, and the solder quality is superior to that of the prior art soldering.

    In the case of the soldering method according to the second embodiment of the present invention, the flow-soldered mounting substrate is heated in a reflow furnace and the entire substrate is uniformly heated and held, so that the solder at the solder joint is remelted and uniformly heated and held. Thus, there is no variation in temperature before rapid solidification at the mounting positions (front portion 71f, central portion 71m, rear portion 71r), and the entire substrate is rapidly solidified from the solder molten state that is uniformly heated and held. Therefore, the variation in the cooling rate is small, the solder structure becomes uniform regardless of the component mounting position, and the variation in Sn crystal grain in the solder solidification structure of the solder joint becomes small, so the variation in crack length (life) becomes small. , Variation in crack length (life) is reduced.

  As described above, in the conveyor type soldering apparatus of the present invention, by performing the soldering method of the present invention, the flow-processed mounting board subjected to flow soldering is heated and the entire mounting board is uniformly heated and held. As a result, the solder in the solder joint is remelted and uniformly heated and held regardless of the component placement position. Since the entire substrate is rapidly cooled from the held state and the solder in the solder joint is uniformly solidified, there is no lift-off, the number of shrinkage cavities is small, and the solder crack length is short and stable. Good soldering quality can be obtained.

FIG. 1A is a flowchart of a soldering method in the present invention, FIG. 1A is a flowchart of a soldering method (remelting type) in the first embodiment, and FIG. 1B is a soldering method in the second embodiment ( It is a flowchart of a melt holding format. It is a schematic block diagram of the soldering apparatus in the 1st Embodiment of this invention. It is a schematic block diagram of the soldering apparatus in the 2nd Embodiment of this invention. It is a flowchart of the conventional flow soldering method. It is a flowchart of the conventional reflow soldering method. FIG. 6 shows a reflow furnace 110, FIG. 6 (a) is a schematic diagram showing an outline of the reflow furnace 110, and FIG. 6 (b) is a schematic diagram showing a longitudinal sectional structure of the reflow furnace. It is a schematic diagram which shows the surface temperature of the board | substrate which concerns on the soldering apparatus 1, and the positional relationship of a board | substrate and an apparatus structure part. It is a schematic diagram which shows the surface temperature of the board | substrate concerning the soldering apparatus 2, and the positional relationship of a board | substrate and an apparatus structure part. The schematic diagram of the printed wiring board 70 carrying an electronic component is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2: Soldering apparatus 10, 25: Process diagram of soldering method 50a: Component mounting board 50b: Component mounting board 50f: Flow processing mounting board 50r: Reflow processing mounting board 55: Solder joint part
70: Printed wiring board on which electronic components for testing are mounted 100: Flow furnace 110, 120: Reflow furnace 111: Solder melting / uniform heating section 112: Rapid cooling section 115: Heating nozzle 116: Cooling nozzle

Claims (6)

In a soldering method using a lead-free solder material on a printed circuit board or surface-mounted components mounted on a printed wiring board or a surface-mounted component using a conveyor type soldering device, the lead terminal is inserted into the through hole and the insertion type electronic component is mounted After the printed wiring board or the printed circuit board is soldered and solidified , the printed wiring board or the printed circuit board is transferred into a reflow furnace, and the printed wiring board or the printed circuit inside the reflow furnace is loaded. The printed wiring board or the entire printed circuit board is made of the solder material by hot air blown from a hot air blowing nozzle arranged in the vertical direction of the board to a range including the entire surface of the printed wiring board or the printed circuit board. the insertion Thailand of being heated to a temperature above the melting point of the defined, is the soldered Was melted again solder of the solder joint of the electronic component, the said at prescribed temperature above the melting point printed circuit board or the printed circuit board uniformly heated and held, the printed wiring board or the internal of the reflow furnace The printed wiring board that is uniformly heated and held by the refrigerant that is jetted from a cooling nozzle that is disposed in the vertical direction of the printed circuit board to a range that includes the entire surface of the printed wiring board or the printed circuit board, or the A method for soldering a printed wiring board or a printed circuit board, wherein the entire printed circuit board is cooled at the same time and the re-melted solder is solidified. In a soldering method using a lead-free solder material on a printed circuit board or surface-mounted components mounted on a printed wiring board or a surface-mounted component using a conveyor type soldering device, the lead terminal is inserted into the through hole and the insertion type electronic component is mounted When the printed wiring board or the printed circuit board is soldered, before the soldered solder is solidified, the printed wiring board or the printed circuit board is transported and charged into a reflow furnace, and the reflow furnace Hot air blown from a nozzle for heating hot air arranged in the vertical direction of the printed wiring board or the printed circuit board inside, or a range including the entire surface of the printed wiring board or the printed circuit board, or of the reflow furnace For cooling arranged in the vertical direction of the printed wiring board or the printed circuit board inside Wherein the refrigerant from the refrigerant ejection nozzle is ejected in a range including the entire surface of the printed wiring board or the printed circuit board printed wiring board or the printed circuit board is heated or cooled to a more defined melting point temperature, the A printed wiring board or printed circuit board characterized in that the entire printed wiring board or printed circuit board uniformly heated and held at a temperature equal to or higher than a specified melting point is cooled at the same time and the molten solder is solidified. Soldering method. A conveyor type soldering apparatus used in the method of soldering a printed wiring board or printed circuit board according to claim 1 or 2, the flow reactor composed of pre-heating unit and a solder bath, a rear portion of the flow reactor A reflow furnace in which a heating unit and a cooling unit are integrally configured, a conveyor disposed on the same line of the flow furnace and the reflow furnace, and a position of a soldering substrate conveyed on the conveyor The flow furnace and the reflow furnace according to the position data from the detection part of the sensor, the detection part for reading the position data from the signal of the sensor, and the detection part of the printed circuit board on which the printed wiring board or the surface mounting component is mounted And a controller for controlling the heating and cooling of the conveyor and the speed of the conveyor ,
The reflow furnace is a heating circuit disposed in the reflow furnace in order to uniformly heat the printed wiring board or the printed circuit board on which the surface-mounted components mounted in the reflow furnace are mounted. A hot-air jet nozzle and a cooling-jet nozzle for cooling disposed in the reflow furnace for uniform cooling, and in response to a request from the controller, hot air for heating is used for the hot-air jet A conveyor type soldering apparatus , wherein heating and cooling can be switched instantaneously by ejecting from a nozzle or ejecting a cooling refrigerant from the refrigerant ejection nozzle . A conveyor type soldering apparatus used in the method of soldering a printed wiring board or printed circuit board according to claim 1 or 2, the flow reactor composed of pre-heating unit and a solder bath, a rear portion of the flow reactor including a reflow furnace which is integrally formed, a conveyor branch portion for branching the transfer line into two or more in the middle of the flow reactor and before Symbol reflow furnace, the conveyor branch section and the cooling section connected to the heating unit is in A first conveyor, a branched second conveyor, another reflow furnace connected to the second conveyor, and the printed wiring board or the printed circuit conveyed on the first and second conveyors A sensor that detects the position of the board, a detection unit that reads position data from the signal of the sensor, and a printed circuit board on which the printed wiring board or the surface-mounted component is mounted. The printed wiring in which the heating and cooling of the flow furnace and the two or more reflow furnaces, the first and second conveyor speeds, and the flow soldering at the branching portion are completed based on position data from the detection unit of the circuit board A controller for controlling the sorting of the printed circuit board on which the board or the surface mounting component is mounted ,
The reflow furnace is a heating circuit disposed in the reflow furnace in order to uniformly heat the printed wiring board or the printed circuit board on which the surface-mounted components mounted in the reflow furnace are mounted. A hot-air jet nozzle and a cooling-jet nozzle for cooling disposed in the reflow furnace for uniform cooling, and in response to a request from the controller, hot air for heating is used for the hot-air jet A conveyor type soldering apparatus , wherein heating and cooling can be switched instantaneously by ejecting from a nozzle or ejecting a cooling refrigerant from the refrigerant ejection nozzle . 3. The print according to claim 1, wherein the temperature equal to or higher than the specified melting point is within a temperature range of a melting point of the solder material + 5 ° C. or more and a heat resistant temperature of the electronic component to be soldered−5 ° C. or less. Soldering method for wiring boards or printed circuit boards . The lead-free solder materials are Sn—Cu, Sn—Ag, Sn—Ag—Cu, Sn—Ag—Cu—Bi, Sn—Ag—Cu—Sb, Sn—, which are basic solder materials mainly composed of Sn. Ag-Bi-In, Sn-Ag-In, Sn-Zn, Sn-Zn-Bi, Sn-Sb, and the basic solder materials include Al, Si, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Ga, Ge, As, Se, Zr, Nb, Mo, Pd, Hf, Ta, W, Pt, and any material selected from lead-free solder materials to which trace amounts of Au are added The printed wiring board or printed circuit board soldering method according to claim 1, wherein the printed wiring board or printed circuit board is soldered.

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