JP4457369B1 - Soldering apparatus, soldering method, and method of manufacturing soldered product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure better solderability by injecting molten solder directly onto a joining portion without preheating a joining portion of an electronic component or a substrate or heating the solder to a temperature higher than necessary for melting. It is to provide a soldering apparatus, a soldering method, and a method for manufacturing a soldered product capable of performing soldering.
A soldering apparatus includes solder spraying means for spraying molten linear solder to a joint portion of a part to be soldered, and energizing means for heating the sprayed linear solder by energization. Yes.
[Selection] Figure 1

Description

  The present invention relates to a soldering apparatus, a soldering method, and a method for manufacturing a soldered product that perform soldering by injecting a molten solder alloy onto a joint portion between an electronic component and a substrate.

  Conventionally, as a method of soldering an electronic component to a substrate, a method of locally heating a joint portion from the outside has been adopted. Physically, as a heating method for the joint portion, a first heating method using heat conduction by a soldering iron, or a second heating method using radiation by irradiating infrared rays or a laser (for example, see Patent Document 1). ) And a third heating method (see, for example, Non-Patent Document 1) that utilizes heat transfer by jetting and convection of a liquid such as gas or molten solder.

  The soldering method using the first soldering iron is to preheat the soldering portion with the heat of the soldering iron and then melt the thread-like solder alloy for soldering. However, there is a drawback that preheating takes time and the amount of solder used varies depending on the molten state of the solder.

  The heating by the second laser is used not only for melting the solder but also for preliminary heating of the soldering portion. Therefore, there is a drawback that not only soldering takes time, but also the amount of solder used tends to vary.

  The soldering method for jetting the third molten solder is to heat the substrate with heat from the convective molten solder. However, there is a problem that it takes time to heat the substrate. Therefore, as a method of soldering with high accuracy and high speed using molten solder, a method of injecting a molten solder alloy directly to a joint portion has been proposed (for example, see Patent Document 2).

JP 2005-111531 A JP 2008-085247 A

JIS C 60068-2-58

  However, in the conventional method of directly injecting molten solder alloy to the joint portion, ball-shaped molten solder is supplied to the soldering portion. For this reason, the amount of heat of the molten solder may cause the molten solder to solidify before the joint is sufficiently heated, and the solder may not be welded to the joint. Even if a part of the ball-shaped molten solder is welded to the joining portion, there is a problem that if the molten solder is cooled and solidified before spreading around the joining portion, a wide welding area cannot be obtained.

  Therefore, by preheating the electronic parts and the board locally, or by setting the furnace temperature in the melting furnace for generating the molten solder to be a temperature at which the injected molten solder does not solidify, the solder Adequacy is secured.

  However, when preheating the joining portion, heating equipment and heating time for the joining portion are required. Further, in order to increase the temperature in the melting furnace, not only the durability of the melting furnace is required for high temperatures, but also there is a problem that the solder is oxidized and deteriorated in the melting furnace.

  The present invention has been made to solve such a conventional problem, and it is possible to directly apply the molten solder without preheating the joining portion of the electronic component or the substrate or heating the solder to a temperature higher than necessary for melting. An object of the present invention is to provide a soldering apparatus, a soldering method, and a method for manufacturing a soldered product capable of performing soldering while ensuring better solderability by spraying on a joint portion.

In order to achieve the above-mentioned object, the soldering apparatus according to the present invention includes a solder spraying means for spraying molten solder in a linear shape to a joint portion of a part to be soldered, and energizing the solder sprayed in the linear shape. Thus, an energization means for heating the solder is provided.

In addition, the soldering method according to the present invention includes a step of spraying molten solder in a linear shape to a joint portion of a component to be soldered, and energizing the solder sprayed in the linear shape in order to achieve the above-described object. And heating the solder .

Moreover, in order to achieve the above-mentioned object, the method for manufacturing a soldered product according to the present invention includes a step of injecting molten solder into a joint portion of a part to be soldered in a linear shape, and the linear injection method. and has a heating said solder by energizing the solder.

  According to the soldering apparatus, the soldering method, and the soldered article manufacturing method according to the present invention, it is possible to melt without preheating the joint part of the electronic component or the substrate or heating the solder to a temperature higher than necessary for melting. By spraying the solder directly onto the joint portion, it is possible to perform soldering while ensuring better solderability.

Sectional drawing which shows the structure of the soldering apparatus which concerns on embodiment of this invention. The figure which shows the example which has arrange | positioned the component side electrode shown in FIG. 1 in the position which can contact the terminal of the electronic component used as the junction part of a to-be-soldered component. The figure which shows the example which has arrange | positioned the component side electrode shown in FIG. 1 in the position which can contact the land part of the board | substrate used as the junction part of to-be-soldered components. The figure which shows the example arrange | positioned in the position which can contact a molten solder alloy in the vicinity of a junction part, without contacting the component side electrode shown in FIG. The figure which shows the example which connected the component side electrode shown in FIG. 1 with the arbitrary parts of the to-be-soldered components electrically connected with the junction part. The figure which compared the result of the soldering test by the soldering apparatus shown in FIG. 1, and the result of the soldering test by the conventional soldering method. The figure explaining the evaluation result of the soldering shown in FIG. 6 to a schematic diagram.

  Embodiments of a soldering apparatus, a soldering method, and a method for manufacturing a soldered product according to the present invention will be described below with reference to the accompanying drawings.

(Configuration and function)
FIG. 1 is a cross-sectional view showing a configuration of a soldering apparatus according to an embodiment of the present invention.

  The soldering apparatus 1 includes a molten solder injection system 2, a component drive system 3, a flux spray system 4, and a control system 5. The molten solder injection system 2 includes a solder melting furnace 6, a connection path 7, an on-off valve chamber 8, an on-off valve 9, an on-off valve driving device 10, an orifice 11, an energization device 12, a device side electrode 13 as a first electrode, a first electrode. 2, a component side electrode 14 as an electrode, an insulating component 15, a gas supply path 16, a gas supply device 17, and a gas pressure adjusting unit 18 are provided. The control system 5 includes an on-off valve control unit 19, an energization condition control unit 20, a component drive control unit 21 and a synchronization unit 22. Components for performing information processing such as the control system 5 and the gas pressure adjusting unit 18 can be constructed by causing a circuit or a computer to read a program.

  The component drive system 3 sets a soldered component 25 to be soldered, such as the electronic component 23 and the substrate 24, and sets a joint portion 26 of the set component at a desired position according to a control signal from the component drive control unit 21. It has the function to position the joining part 26 used as a soldering part by moving to. The component drive system 3 is configured to be able to move the joint portion 26 of the component to be soldered 25 in, for example, three axis directions of the X axis, the Y axis, and the Z axis. Instead of moving the soldered component 25 or in addition to the movement of the soldered component 25, the molten solder injection system 2 side may be moved.

  The molten solder injection system 2 has a function of injecting an electrically heated molten solder alloy to a joint portion 26 of a component to be soldered 25 such as an electronic component 23 or a substrate 24 set in the component driving system 3. The flux spraying system 4 has a function of spraying flux onto the joint portion 26 of the soldered component 25. The control system 5 has a function of controlling the molten solder injection system 2, the component drive system 3, and the flux spray system 4.

  The solder melting furnace 6 of the molten solder injection system 2 is connected to a gas supply device 17. The solder melting furnace 6 has a function of generating a molten solder alloy by heating and melting the solder alloy to a melting point or higher in a state where the gas supplied from the gas supply device 17 is filled inside. Further, the inside of the solder melting furnace 6 is connected to the inside of the on-off valve chamber 8 via a plurality of connecting paths 7 so that the molten solder alloy and gas can move into the on-off valve chamber 8.

  The opening / closing valve chamber 8 is provided with a hole as the solder injection portion 27. The solder injection portion 27 of the on-off valve chamber 8 is provided at a position where the molten solder alloy can be injected toward the joint portion 26 of the soldered component 25 set in the component drive system 3. The shape of the on-off valve chamber 8 in the vicinity of the solder injection portion 27 is desirably an elongated shape so that the solder injection portion 27 can be sufficiently approached even if the joint portion 26 of the component to be soldered 25 has various shapes. The on-off valve 9 is provided so as to be able to open and close the solder injection portion 27 from the outside of the on-off valve chamber 8 through the on-off valve chamber 8. That is, the on-off valve 9 is configured to be driven inside the on-off valve chamber 8.

  The on-off valve driving device 10 has a function of opening / closing the on-off valve 9 by driving the on-off valve 9 in accordance with a control signal from the on-off valve control unit 19. For the on-off valve driving device 10, for example, a piezo element that deforms when a voltage is applied can be used.

  An orifice 11 is provided outside the solder injection portion 27 of the on-off valve chamber 8. The orifice 11 has a nozzle hole having a desired diameter. Then, the linear molten solder alloy is injected from the solder injection portion 27 of the on-off valve chamber 8 through the nozzle hole of the orifice 11 to the joint portion 26 of the component to be soldered 25. The orifice 11 can be configured to be detachable from the on-off valve chamber 8. Therefore, a plurality of orifices 11 having nozzle holes of desired diameters having different sizes for adjusting the diameter of the molten solder alloy are prepared in advance, and the molten solder alloy to be supplied to the joint portion 26 of the component to be soldered 25 It is possible to select an orifice 11 having a nozzle hole of a size appropriate for the injection amount of the nozzle and mount it in the on-off valve chamber 8. Note that the orifice 11 having a variable nozzle hole may be set in the solder injection unit 27.

  The upstream end of the gas supply path 16 is connected to the gas supply device 17, while the downstream end is installed in the vicinity of the molten solder alloy injected from the orifice 11. The gas supply path 16 has a function of preventing oxidation of the injected molten solder alloy by blowing the gas supplied from the gas supply device 17 onto the molten solder alloy injected from the orifice 11.

The gas supply device 17 has a function of supplying gas to the inside of the solder melting furnace 6 and the gas supply path 16. The gas supplied to the inside of the solder melting furnace 6 and the gas supply path 16 is preferably an inert gas such as nitrogen (N ₂ ) gas from the viewpoint of preventing deterioration due to oxidation of the solder alloy. The gas supplied to the inside of the melting furnace and the gas supply path 16 may be the same to simplify the structure of the apparatus, or may be different to make the material suitable for the atmosphere and purpose of the solder alloy. Good.

  The gas pressure adjusting unit 18 is connected to the gas supply device 17. The gas pressure adjusting unit 18 has a function of controlling the gas pressure in the solder melting furnace 6 and the on-off valve chamber 8 by controlling the amount of gas supplied from the gas supply device 17 into the solder melting furnace 6. Have. Further, the gas pressure adjusting unit 18 may be configured to adjust the pressure of the gas sprayed from the gas supply device 17 to the molten solder alloy via the gas supply path 16.

  On the other hand, the energization device 12 includes a switch 12A, a DC power source, and a variable resistor, and is electrically connected to the device-side electrode 13 and the component-side electrode 14. The energization device 12 has a function of applying a desired voltage and / or a function of supplying a desired current between the device-side electrode 13 and the component-side electrode 14 in accordance with the output voltage control signal from the energization condition control unit 20. Have.

  The device-side electrode 13 is electrically connected to an arbitrary position of the molten solder injection system 2 that can be energized with the molten solder alloy injected from the solder injection portion 27 of the on-off valve chamber 8. FIG. 1 shows an example in which the device-side electrode 13 is fixed to the on-off valve chamber 8 when the wall surface of the on-off valve chamber 8 is a conductor. On the other hand, the component-side electrode 14 is injected from an arbitrary position of the soldered component 25 that can be energized with the molten solder alloy injected from the solder injection portion 27 of the on-off valve chamber 8 or from the solder injection portion 27 of the on-off valve chamber 8. It is provided at an arbitrary position where it can contact the molten solder alloy itself. The component side electrode 14 can be fixed to the energization device 12, but if the component side electrode 14 is fixed to an arbitrary position of the molten solder injection system 2 via the insulating component 15, the strength of the component side electrode 14 is kept good. The component side electrode 14 can be easily disposed at a desired position. FIG. 1 shows an example in which the component side electrode 14 is fixed to the on-off valve chamber 8 via the insulating component 15 and the device side electrode 13.

  FIG. 2 is a view showing an example in which the component side electrode 14 shown in FIG. 1 is arranged at a position where it can come into contact with a terminal of the electronic component 23 that becomes the joint portion 26 of the soldered component 25.

  As shown in FIG. 2, the opening / closing valve 9 is moved in a state where the component side electrode 14 is brought into contact with the terminal 23A of the electronic component 23 and the gas pressure in the solder melting furnace 6 and the opening / closing valve chamber 8 is sufficiently high. When the solder injection portion 27 of the on-off valve chamber 8 is opened for a predetermined time, a linear molten solder alloy is injected from the solder injection portion 27 toward the joint portion 26 of the component to be soldered 25 by the action of gas pressure. For this reason, from the energization device 12 to the device side electrode 13, the on-off valve chamber 8, the linear molten solder alloy, the solder alloy 26 </ b> A attached to the joint portion 26 of the component to be soldered 25, the terminal 23 </ b> A of the electronic component 23 and the component side electrode A current loop returning to the energization device 12 again via 14 is formed.

  Therefore, by the action of the current flowing through the current loop from the energization device 12, that is, by energizing the joint portion 26 of the linear molten solder alloy and the soldered component 25, The joining portion 26 can be heated to a temperature equal to or higher than the melting point of the solder alloy. That is, the current flowing through the energization device 12 and the current loop functions as a heating means for the joint portion 26 of the linear molten solder alloy and the soldered component 25.

  As a result, the molten solder alloy does not solidify before welding, and sufficiently spreads in the joint portions 26 such as the land portions 24A and the terminals 23A of the substrate 24, and the wet molten solder alloy can be favorably welded to the joint portions 26. it can. As shown in FIG. 2, if the component-side electrode 14 is brought into contact with the tip of the terminal 23 </ b> A of the electronic component 23, the terminal 23 </ b> A of the electronic component 23 that is the joint portion 26 can be reliably heated. For this reason, better soldering can be performed.

  FIG. 3 is a view showing an example in which the component side electrode 14 shown in FIG. 1 is arranged at a position where the component side electrode 14 can come into contact with the land portion 24 </ b> A of the substrate 24 that becomes the joint portion 26 of the soldered component 25.

  As shown in FIG. 3, even when the component side electrode 14 is brought into contact with the land portion 24A of the substrate 24, a linear molten solder alloy and It can heat so that the junction part 26 of the to-be-soldered component 25 may become the temperature more than melting | fusing point of a solder alloy. In this case, if the plurality of joint portions 26 have the same or similar shapes, the component drive system 3 is driven to move the component to be soldered 25 and the land portion 24A of the substrate 24 and the component side electrode 14 are moved. There is an advantage that relative positioning between the two becomes easy.

  FIG. 4 is a view showing an example in which the component side electrode 14 shown in FIG. 1 is arranged at a position where it can contact the molten solder alloy in the vicinity of the joint portion 26 without contacting the soldered component 25.

  As shown in FIG. 4, even if the component side electrode 14 is brought into direct contact with the molten solder alloy at a position away from the joint portion 26 instead of being brought into contact with the component to be soldered 25, the molten solder sprayed to the tip of the component side electrode 14 The alloy can be sufficiently heated by energization. And since the heated molten solder alloy is released from energization while maintaining a high temperature state above the melting point and supplied to the joint portion 26, the molten solder alloy can be soldered well without solidifying before welding. Can do. In this case, since no current flows through the electronic component 23 and the substrate 24, there is an advantage that electrical shock can be reduced by avoiding unnecessary leakage of current to the electronic component 23 and the substrate 24.

  When the component-side electrode 14 is arranged in the vicinity of the joint portion 26, the component-side electrode 14 is fixed to the joint portion 26 when the molten solder alloy is solidified with the component-side electrode 14 entering the molten solder alloy. there is a possibility. Therefore, after the molten solder alloy is supplied to the joint portion 26, the component drive system 3 is set so that the entire soldered component 25 or only the terminal 23A of the electronic component 23 is separated from the component side electrode 14 before the molten solder alloy is solidified. You may control.

  FIG. 5 is a diagram illustrating an example in which the component-side electrode 14 illustrated in FIG. 1 is connected to an arbitrary part of the soldered component 25 that is electrically connected to the joint portion 26.

  As shown in FIG. 5, the wire-like component-side electrode 14 can be connected to a land portion 24 </ b> A on the substrate 24 that is electrically connected to the joint portion 26. Note that the wire-shaped component-side electrode 14 may be connected to a terminal 23 </ b> A having an electronic component 23 that is electrically connected to the joint portion 26. Also in this case, if the molten solder alloy is injected when the joint portion 26 is at the injection position of the molten solder alloy, the device-side electrode 13, the on-off valve chamber 8, the linear molten solder alloy, the soldered object, etc. Heat is applied so that the molten solder alloy does not solidify before welding due to the current flowing through the current loop that returns to the energization device 12 again via the joint portion 26 of the attachment component 25, the conductor on the component to be soldered 25, and the component side electrode 14. be able to. In this case, since it is not necessary to fix the component side electrode 14 to the molten solder injection system 2, as shown in FIG. 5, the component side electrode 14 and the device side electrode 13 are used as the tips of the electric wires, and the insulating component 15 is It does not have to be provided. For this reason, the structure of the electrode is simplified.

  Instead of connecting the device side electrode 13 to the molten solder injection system 2, the apparatus side electrode 13 may be brought into direct contact with the molten solder alloy on the upstream side in the vicinity of the solder injection portion 27. In this case, since electric power is not consumed in the molten solder injection system 2 such as the wall surface of the on-off valve chamber 8, the electric power can be efficiently used for heating the molten solder alloy.

  Next, detailed functions of the control system 5 will be described.

  The on-off valve control unit 19 has a function of opening and closing the on-off valve 9 at a desired timing by sending a control signal to the on-off valve driving device 10 to drive it. The energization condition control unit 20 transmits a control signal to the energization device 12 and controls the energization device 12 so that a desired output voltage and / or output current is output from the energization device 12 at a desired timing, that is, the energization device. It has a function of controlling 12 output voltages and output currents. The component drive control unit 21 has a function of moving the soldered component 25 to a desired position and positioning the joint portion 26 at a desired timing by sending a control signal to the component drive system 3 to drive it.

  The synchronization unit 22 sends the synchronization signal to the on-off valve control unit 19, the energization condition control unit 20, the switch 12 </ b> A of the energization device 12, the component drive control unit 21, and the flux spray system 4, thereby 12, the change timing of the output voltage and / or output current from the switch 12, the opening / closing timing of the switch 12A of the energizing device 12, the drive timing of the component drive system 3, and the spray timing of the flux from the flux spray system 4 are respectively desired delays from the trigger signal. It has a function of controlling the timing so that the time elapses. For example, after the flux is sprayed at the timing when the positioning of the joint portion 26 of the soldered component 25 is completed, the switch 12A of the energization device 12 is closed and the on-off valve 9 is appropriately output in a state where an appropriate current and voltage are output. The on-off valve control unit 19, the energization condition control unit 20, the component drive control unit 21 and the flux spraying system 4 can be comprehensively controlled so that the molten solder alloy which is opened and heated for a period of time is injected.

However, the flux spraying system 4 may be controlled such that the flux is sprayed simultaneously with the spraying of the molten solder alloy without being sprayed prior to the spraying of the molten solder alloy. Moreover, a well-known method can be used for the application method of a flux. Therefore, the operator may apply the flux to an appropriate portion of the joining portion 26 without providing the flux spraying system 4. The synchronization unit 22 can also stop energization by opening the switch 12A of the energization device 12 at a timing earlier than the timing of closing the on-off valve 9. In this case, it is possible to prevent arc discharge from the molten solder alloy interrupted immediately after closing the on-off valve 9. Thereby, even if the electronic circuit of the component to be soldered 25 may be adversely affected by the arc discharge, since the arc discharge does not occur, the adverse effect on the electronic circuit can be avoided. In this way, the synchronization unit 22 and the switch 12A of the energization device 12 can be used as switch means for stopping energization so that arc discharge does not occur from the disconnected molten solder alloy.
Conversely, arc discharge can be intentionally generated from the molten solder alloy. In this case, the energy of the discharge can also contribute to the heating of the molten solder alloy or the part to be soldered 25. Therefore, if it is acceptable to generate arc discharge, the energization device 12 may not be provided with the switch 12A, and if the on-off valve 9 is closed, the energization may be stopped because the molten solder alloy is interrupted.

(Operation and action)
Next, the operation and action of the soldering apparatus 1 will be described.

  First, a component to be soldered 25 such as an electronic component 23 or a substrate 24 is set in the component drive system 3. Further, an orifice 11 having a nozzle hole having a size appropriate for the injection amount of the molten solder alloy to be supplied to the joint portion 26 of the soldered component 25 is mounted in the on-off valve chamber 8. If another orifice 11 is already mounted in the on-off valve chamber 8, it is replaced with an appropriate orifice 11.

  On the other hand, the solder melting furnace 6 is filled with a solder alloy. At this time, the on-off valve 9 of the on-off valve chamber 8 is closed. A predetermined amount of inert gas is supplied from the gas supply device 17 into the solder melting furnace 6 in accordance with a control signal from the gas pressure adjusting unit 18. As a result, the inside of the solder melting furnace 6 is filled with an inert gas having a predetermined pressure. In this state, the solder alloy is heated in the solder melting furnace 6 to produce a molten solder alloy. At this time, since the inert gas is filled in the solder melting furnace 6, the molten solder alloy is prevented from being oxidized. The molten solder alloy generated in the solder melting furnace 6 is guided to the on-off valve chamber 8 through the connection path 7.

  Next, the component drive control unit 21 drives the component drive system 3 in accordance with the synchronization signal from the synchronization unit 22, and the joining portion 26 of the soldered component 25 is positioned at the molten solder alloy injection position. For this reason, the device-side electrode 13 connected to the energization device 12 is disposed at a position in contact with or near the terminal 23A of the electronic component 23 and the land portion 24A of the substrate 24.

  Then, a synchronizing signal is output from the synchronizing part 22 to the flux spraying system 4, and prior to the injection of the molten solder alloy, the soldering parts such as the land part 24A of the substrate 24 and the terminals 23A of the electronic component 23 from the flux spraying system 4 Flux is sprayed on the 25 joint portions 26. Thereby, the wettability of the molten solder alloy in the joint portion 26 is improved.

  Next, the on-off valve control unit 19 drives the on-off valve 9 by sending a control signal to the on-off valve driving device 10 according to the synchronization signal from the synchronization unit 22 and opens the on-off valve 9. Then, the molten solder alloy is driven by the pressure of the inert gas filling the solder melting furnace 6 from the solder injection portion 27 of the on-off valve chamber 8 through the nozzle hole of the orifice 11 and the joint portion 26 of the component to be soldered 25. Inject towards. At this time, the on-off valve 9 is opened for a predetermined time by the control of the on-off valve driving device 10 by the on-off valve control unit 19. As a result, the molten solder alloy becomes linear.

  On the other hand, a predetermined amount of inert gas is supplied from the gas supply device 17 to the gas supply path 16 under the control of the gas pressure adjusting unit 18. For this reason, the inert gas passes through the gas supply path 16 and is discharged from the gas supply path 16 in the vicinity of the orifice 11 and is sprayed onto the molten solder alloy in the vicinity of the orifice 11. Thereby, oxidation of the molten solder alloy injected from the orifice 11 is prevented.

  Here, in order for the board | substrate 24 and the electronic component 23 of a room temperature state to be soldered with a molten solder alloy, the temperature of the metal surface of the joining parts 26, such as the board | substrate 24 and the electronic component 23, is heated more than melting | fusing point temperature of a solder alloy. Need to be. If the temperature of the metal surface of the substrate 24 and the electronic component 23 is lower than the melting point of the solder alloy, the molten solder alloy that has reached the joint portion 26 is cooled and solidified in a state where the molten solder alloy is insufficiently wet and spread. Resulting in. In other words, the substrate 24 and the electronic component 23 cannot be soldered unless the temperature of the substrate 24 and the electronic component 23 is sufficiently high.

  In other words, when the molten solder alloy comes into contact with the joint portion 26 such as the substrate 24 or the electronic component 23, the molten solder alloy will not cool and solidify if the metal surface of the joint portion 26 can be heated above the melting temperature of the solder alloy. The substrate 24 and the electronic component 23 can be soldered. Accordingly, in order to maintain the molten state of the molten solder alloy itself even when the molten solder alloy having a temperature equal to or higher than the melting point flies to reach the joint portion 26 and heat is transferred from the molten solder alloy to the metal surface of the joint portion 26. It is necessary to add the necessary amount of heat.

  Therefore, the switch 12A of the energizing device 12 is closed at a timing before the on-off valve 9 is opened according to the synchronizing signal from the synchronizing unit 22, and a control signal is output from the energizing condition control unit 20 to the energizing device 12, and the energizing device 12 in advance. A desired voltage is applied between the device side electrode 13 and the component side electrode 14. For this reason, at the moment when the molten solder alloy sprayed from the nozzle hole of the orifice 11 reaches the joint portion 26, it again passes through the device side electrode 13, the on-off valve chamber 8, the molten solder alloy and the component side electrode 14 from the energizing device 12. A current loop returning to the energization device 12 is formed, and the molten solder alloy is energized. At this time, when the component-side electrode 14 is in contact with the terminal 23A of the electronic component 23 and the land portion 24A of the substrate 24, the terminal 23A of the electronic component 23 and the land portion 24A of the substrate 24 are also energized.

  As a result, the energized molten solder alloy is instantaneously heated by electric resistance. In particular, the sprayed molten solder alloy is very thin and has a high electric resistance. Therefore, electric power can be easily converted into heat in the molten solder alloy, and the molten solder alloy can be sufficiently heated. As a result, the molten solder alloy is rapidly heated to a higher temperature than the melting temperature in the solder melting furnace 6.

  The injected molten solder alloy reaches the joint portion 26 between the electronic component 23 and the substrate 24 while maintaining a molten state while being energized and heated. At this time, the heat of the molten solder alloy is transmitted to the surface of the joint portion 26 between the electronic component 23 and the substrate 24, and the joint portion 26 between the electronic component 23 and the substrate 24 is heated. As a result, the joint portion 26 is heated to a sufficient temperature not lower than the melting point of the solder alloy. Furthermore, when the terminal 23A of the electronic component 23 or the land portion 24A of the substrate 24 is in contact with the component-side electrode 14, the joining portion 26 is directly energized and heated to a sufficient temperature equal to or higher than the melting point of the solder alloy. Thereby, the molten solder alloy spreads well in the joint portion 26, and the electronic component 23 and the substrate 24 can be soldered well.

  The temperature of the molten solder alloy during flight is determined by the output current or output voltage of the energizing device 12 and the injection time of the molten solder alloy. Accordingly, the output current or output voltage of the energizing device 12 and the injection time of the molten solder alloy are set so that the joining portion 26 has a temperature at least equal to or higher than the melting point of the solder alloy. The energizing device 12 and the open / close valve 19 are controlled by the control signal from the energizing condition control and the control signal from the on-off valve control unit 19 so that the set output current or output voltage of the energizing device 12 and the injection time of the molten solder alloy are obtained. The valve driving device 10 is controlled. That is, the temperature of the molten solder alloy and the joint portion 26 is controlled by the output current or output voltage of the energization device 12 and the injection time of the molten solder alloy.

  What is important here is that the device-side electrode 13 and the component-side electrode 14 are electrically connected via a molten solder alloy during soldering. That is, energization heating becomes possible only when the device side electrode 13 and the component side electrode 14 are connected. Therefore, it is important that the molten solder alloy is not sprayed intermittently as one or a plurality of molten solder balls, but continuously as a linear molten solder alloy in a connected state.

  In order to make the molten solder alloy linear, the opening / closing time of the opening / closing valve 9 may be made sufficiently long. That is, while the on-off valve 9 is open, the molten solder alloy is connected from the nozzle hole of the orifice 11 to the joint portion 26. The opening / closing time of the opening / closing valve 9 can be adjusted by controlling the opening / closing valve driving unit by the opening / closing valve control unit 19. In addition, in order to maintain the injected molten solder alloy in a connected state, it is also important to set the pressure of the inert gas filling the solder melting furnace 6 to a sufficient pressure. The pressure of the inert gas inside the solder melting furnace 6 can be controlled by controlling the gas supply device 17 by the gas pressure adjusting unit 18.

  Furthermore, by adjusting the injection time of the molten solder alloy, that is, the opening / closing time of the on-off valve 9, the injection amount of the molten solder alloy can be controlled. For example, the longer the time during which the on-off valve 9 is open, the longer the injection time of the molten solder alloy, and the greater the amount of molten solder alloy supplied to the joint portion 26. Therefore, the amount of the molten solder alloy supplied to the joint portion 26 can be instantly variably adjusted to an appropriate amount for each point according to the size and shape of the substrate 24 and the electronic component 23. For this reason, the soldering precision and reliability in the junction part 26 can be improved. Thus, the on-off valve 9 functions as an injection time adjusting means for adjusting the injection time of the molten solder alloy. However, as long as the injection time of the molten solder alloy can be adjusted, the injection time adjusting means may have another structure.

  Further, the injection amount of the molten solder alloy can be controlled also by adjusting the pressure of the inert gas inside the solder melting furnace 6. That is, the injection speed can be controlled together with the pressure of the molten solder alloy itself by adjusting the pressure of the inert gas. The pressure of the inert gas inside the solder melting furnace 6 can be adjusted in the gas pressure adjusting unit 18 as described above. Therefore, the gas pressure adjusting unit 18 functions as a pressure adjusting unit that controls the injection amount of the molten solder alloy by adjusting the pressure of the molten solder alloy. A device for variably applying pressure to the molten solder alloy itself may be provided in the molten solder injection system 2 as a pressure adjusting means.

  In addition, as described above, the injection amount of the molten solder alloy can be adjusted by substituting the orifice 11 having a different nozzle hole size. The change of the nozzle hole of the orifice 11 is effective when the injection amount of the molten solder alloy is greatly changed.

  As described above, the molten solder injection system 2 can be provided with the injection amount control means for controlling the injection amount of the molten solder alloy exemplified by the injection time adjusting means, the pressure adjusting means and the orifice 11.

For example, a lead wire having a diameter of 0.8 mm is soldered as an electrode terminal of the electronic component 23 to a through-hole electronic substrate having a thickness of 1.2 mm having a land portion 24A having a land diameter of 2.0 mm around a hole having a diameter of 1.0 mm. The amount of solder required for attaching is about 2.0 mm ³ . Further, when the diameter of the nozzle hole of the orifice 11 is φ0.1 mm, the length of the molten solder alloy necessary for setting the supply amount of the molten solder alloy to 2.0 mm ³ is about 250 mm. Therefore, if the injection speed of the molten solder alloy is 2.5 m / s, the appropriate injection time of the molten solder alloy is 100 ms.

In this way, an appropriate amount of molten solder alloy is supplied to the joint portion 26, and at the timing when the soldering is completed, a control signal is output from the on-off valve control unit 19 to the on-off valve driving unit. The on-off valve 9 is closed by driving the on-off valve driving unit. Here, when it is not desirable to affect the part to be soldered 25 by arc discharge, before the on-off valve 9 is closed by the control of the synchronization unit 22 so that arc discharge does not occur from the broken molten solder alloy. At the timing, the switch 12A of the energization device 12 is turned off. Thereby, after energization stops, injection of molten solder alloy stops. Therefore, arc discharge does not occur from the broken molten solder alloy.
Conversely, when arc discharge is used for heating the molten solder alloy and the component to be soldered 25, the switch 12A is controlled to remain on. Therefore, when the on-off valve 9 is closed, the injection of the molten solder alloy is stopped, and the current loop is interrupted, thereby terminating the energization. The arc discharge from the broken molten solder alloy is used for heating the molten solder alloy and the soldered component 25. That is, opening and closing of the on-off valve 9 is used as a substantial switch operation. Therefore, in this case, the switch 12A may not be provided in the energization device 12.

  Next, after the on-off valve 9 is closed according to the synchronization signal from the synchronization unit 22, a control signal is output from the component drive control unit 21 to the component drive system 3. Then, the component drive system 3 is driven, and the next joint portion 26 of the component to be soldered 25 is positioned at the molten solder alloy injection position. For this reason, the device-side electrode 13 connected to the energization device 12 is disposed at a position where it contacts or is adjacent to the terminal 23A of the electronic component 23 to be soldered and the land portion 24A of the substrate 24. Then, soldering is sequentially performed on the plurality of joint portions 26 in the same flow. At this time, the plurality of joint portions 26 can be soldered automatically and efficiently by the synchronization control by the synchronization unit 22. Further, when the soldering of all the joint portions 26 is completed, a soldered product in which all the electronic components 23 are soldered to the substrate 24 is completed.

  That is, the soldering apparatus 1 as described above sprays the molten solder alloy toward the soldering target position so as to form a linear shape, and energizes the molten solder alloy to thereby increase the temperature of the metal surface at the joint portion 26. The temperature of the molten solder alloy is set to a high temperature to such an extent that can be heated above the melting point of the solder alloy.

(effect)
According to the soldering apparatus 1, since the joint portion 26 of the soldered component 25 is instantaneously heated above the melting point of the solder alloy by energization together with the molten solder alloy, the joint portion 26 of the soldered component 25 is irradiated with a laser or the like. There is no need for preheating. For this reason, the joining portion 26 can be soldered at room temperature. In addition, not only a complicated heating facility for the joint portion 26 is unnecessary, but an increase in heating time due to preheating can be avoided.

  Further, since the molten solder alloy after injection is energized and heated, it is not necessary to increase the temperature in the solder melting furnace 6 unnecessarily in anticipation of a temperature drop of the molten solder alloy after injection as in the prior art. In principle, the inside of the solder melting furnace 6 may be heated to a temperature at which the molten state of the molten solder alloy in the solder melting furnace 6 and the on-off valve chamber 8 can be maintained. Actually, it is considered sufficient if the temperature in the solder melting furnace 6 can be maintained at a temperature slightly higher than the melting point of the solder alloy. For this reason, the temperature durability required for the solder melting furnace 6 can be reduced. Further, it is possible to avoid deterioration of the high-temperature solder alloy due to reaction in the atmosphere in the solder melting furnace 6.

  Moreover, according to the soldering apparatus 1, the temperature of the molten solder alloy in the joint portion 26 can be maintained at a high temperature equal to or higher than the melting point. For this reason, the molten solder alloy is sufficiently wetted and spread on the joint portion 26, and good soldering can be performed. Therefore, it is possible to ensure a strong solderability within a necessary range as in the case of soldering using a soldering iron.

  On the contrary, according to the soldering apparatus 1, it is possible to complete the soldering in a short time and with a high degree of accuracy, which is impossible by soldering using a soldering iron. That is, in the soldering apparatus 1, the solder alloy is already melted at the time of soldering. For this reason, the soldering apparatus 1 can perform high-speed soldering without a solder melting step at the time of soldering, like a soldering method using a soldering iron. Furthermore, unlike the soldering method using the soldering iron, the soldering apparatus 1 performs soldering in a non-contact manner. For this reason, in the soldering apparatus 1, even if the electronic components 23 are arranged at a high density on the substrate 24, the relative position between the molten solder alloy spraying position and the joining portion 26 is accurately performed to achieve good soldering. It can be performed.

  Further, the molten solder alloy can be heated from about 1000 ° C. to about 2000 ° C. by energization heating, and the molten solder alloy heated to such a high temperature can be instantaneously improved simply by being sprayed to the joint portion 26. Spread wet. For this reason, the time required for soldering is substantially the injection time of the molten solder alloy. The injection time of the molten solder alloy is, for example, about 0.05 seconds. Therefore, the ability to instantaneously raise the temperature of the molten solder alloy also contributes to speeding up the soldering process.

  Further, in the soldering apparatus 1, the supply amount of the molten solder alloy to be injected is adjusted by adjusting the opening / closing time of the on-off valve 9, the size of the nozzle hole of the orifice 11, and the pressure of the inert gas inside the solder melting furnace 6. Therefore, it can be precisely controlled according to the size and shape of the joint portion 26. For this reason, the soldering apparatus 1 can perform highly accurate soldering with little variation.

  6 is a diagram comparing the result of the soldering test by the soldering apparatus 1 shown in FIG. 1 with the result of the soldering test by the conventional soldering method, and FIG. 7 is an evaluation of the soldering shown in FIG. It is a figure explaining a result to a mimetic diagram.

  The soldering test was performed by spraying a molten solder alloy in a state where a thin flux was applied to the surface of the substrate 24 that was copper-plated on the surface of paper phenol having a thickness of 1.2 mm. As the molten solder alloy, 3Ag-0.5Cu-Sn, which is a standard lead-free solder alloy having a melting point of 220 ° C., was used.

  And without preheating the board | substrate 24, the temperature in the solder melting furnace 6 was set to 250 degreeC using the soldering apparatus 1, and the molten solder alloy was injected from the orifice 11 with a nozzle hole diameter of 0.1 mm. Furthermore, the component side electrode 14 was directly brought into contact with the copper plating surface corresponding to the land portion 24 </ b> A of the substrate 24, whereby the molten solder alloy was energized and heated. The injection time of the molten solder alloy was 100 ms, and the voltage and current during energization were 20 V and about 2 to 3 A, respectively.

  As a result, good solderability was obtained as shown in FIG. That is, as shown in FIG. 7A, the molten solder alloy was sufficiently spread on the substrate 24. Incidentally, a soldering test for joining a lead wire having a diameter of 0.8 mm to the substrate 24 under the same conditions as shown in FIGS. 2 to 5, the component side electrode 14 is connected to the lead wire, the land portion 24A of the substrate 24, the molten solder alloy. When the test was carried out in contact with the conductive portions on the substrate 24, good solderability was obtained in any case.

  On the other hand, when soldering was performed by spraying the molten solder alloy without performing energization of the molten solder alloy and preheating of the substrate 24, the solderability was poor. That is, as shown in FIG. 7C, no solder was deposited on the substrate 24 at all.

  Furthermore, when the substrate 24 was preheated to 200 ° C. and soldering was performed by spraying the molten solder alloy without energizing the molten solder alloy, the solder was partially welded. In addition, even when neither the energization of the molten solder alloy nor the preheating of the substrate 24 is performed, the solder is partially soldered when the molten solder alloy is sprayed at a temperature of 400 ° C. inside the solder melting furnace 6. It became welding. That is, as shown in FIG. 7B, the solder is spread and wet, but is partially attached to the substrate 24, and the solderability as a whole is insufficient.

  From the results of the soldering test shown in FIG. 6, it is possible to obtain good solderability if the molten solder alloy is energized and heated even if the temperature inside the solder melting furnace 6 is 250 ° C. and the substrate 24 is not preheated. I understand that. Therefore, it can be confirmed that the molten solder alloy was heated to a temperature sufficient for soldering. Furthermore, it can be seen from the results of the soldering test shown in FIG. 6 that good solderability can be obtained by setting the energization voltage to 20 V and the molten solder alloy injection time to 100 ms. Therefore, it can be confirmed that the soldering conditions including the voltage at the time of energization and the spraying time have been set appropriately.

DESCRIPTION OF SYMBOLS 1 Soldering apparatus 2 Molten solder injection system 3 Component drive system 4 Flux spray system 5 Control system 6 Solder melting furnace 7 Connection path 8 On-off valve chamber 9 On-off valve drive device 11 Orifice 12 Current supply device 12A Switch 13 Device side electrode 14 Component side electrode 15 Insulating component 16 Gas supply path 17 Gas supply device 18 Gas pressure adjusting unit 19 On-off valve control unit 20 Energizing condition control unit 21 Component drive control unit 22 Synchronizing unit 23 Electronic component 23A Terminal 24 Substrate 24A Land unit 25 Covered Soldering part 26 Joining part 26A Solder alloy 27 Solder injection part

Claims (13)

Solder spraying means for spraying molten solder in a linear shape to the joint portion of the part to be soldered;
Energizing means for heating the solder by energizing the solder injected into the linear,
Soldering device equipped with. The soldering apparatus according to claim 1, further comprising: an injection amount control unit that controls an injection amount of the molten solder. 3. The soldering apparatus according to claim 2, wherein the injection amount control unit includes an injection time adjusting unit that controls an injection amount of the molten solder by adjusting an injection time of the molten solder. 4. The soldering apparatus according to claim 2, wherein the injection amount control means includes pressure adjusting means for controlling an injection amount of the molten solder by adjusting a pressure of the molten solder. The injection quantity control means, soldering apparatus according to any one of claims 2 to 4 comprising a replaceable orifice having a hole for adjusting the diameter of the solder which is the molten 6. The soldering apparatus according to claim 1, wherein the solder injection unit includes a melting furnace that generates the molten solder, and a gas supply device that supplies an inert gas into the melting furnace. 7. . The said energization means is provided with the 1st electrode connected to the position of the said solder injection means which can energize the said melted solder , and the 2nd electrode connected to the said to-be-soldered component. The soldering apparatus according to any one of the above. The energization means is disposed at a position where the first electrode connected to the position of the solder spraying means capable of energizing the molten solder is separated from the soldered component and in contact with the sprayed solder. The soldering apparatus according to claim 1, further comprising a second electrode. The soldering apparatus according to claim 7, further comprising driving means for pulling the second electrode away from the part to be soldered. The soldering apparatus according to any one of claims 1 to 9, further comprising switch means for stopping the energization before the solder is interrupted so that arc discharge does not occur from the solder. Spraying the molten solder in a linear shape onto the joint portion of the component to be soldered;
Heating said solder by energizing the solder injected into the linear,
A soldering method comprising: The soldering method according to claim 11, further comprising a step of applying a flux to the joint portion prior to the solder injection or simultaneously with the solder injection. Spraying the molten solder in a linear shape onto the joint portion of the component to be soldered;
Heating said solder by energizing the solder injected into the linear,
A method for manufacturing a soldered product having

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