JP3897715B2 - Reflow soldering method and reflow soldering apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflow soldering method capable of reducing the influence of scattered solder generated during reflow soldering.
[0002]
[Prior art]
When reflow soldering a part to a surface mount board, which is a work board, when the work board is heated, the solvent contained in the cream solder bumps, and a part of the flux or a small value of 20 μm to 40 μm A situation occurs in which the solder having a particle size is scattered around the soldering portion.
[0003]
When the contact pattern is located around the soldering point as in the surface mount substrate of the mobile phone device, contact failure occurs when scattered flux or solder balls adhere to the contact pattern.
[0004]
Therefore, conventionally, as seen in (Patent Document 1), a foreign matter adhesion prevention wall 60 having a predetermined height is formed on the soldering surface of the work board so as to surround the contact pattern, and the foreign matter 50 scattered during reflow soldering is removed. It is configured to stop.
[0005]
[Patent Document 1]
JP 07-283493 A (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the conventional method in which the foreign matter adhesion preventing wall 60 is provided on the work substrate side, in the case of a mobile phone device incorporating such a work substrate, the substrate becomes thick and the product becomes thick.
[0007]
An object of the present invention is to provide a reflow soldering method capable of preventing scattering of foreign matters during reflow soldering to a protection area on a work substrate without providing a foreign matter adhesion preventing wall on the work substrate side.
[0008]
[Means for Solving the Problems]
In the reflow soldering method of the present invention, when the surface opposite to the soldering surface of the work substrate is heated to reflow solder and mount the component on the soldering surface, the side of the soldering surface of the work substrate is mounted. a position not in contact with said component in said covers the protection area of the soldering surface so as to correspond to the position of the component is disposed a shutter opening formed, the soldering temperature profile by heating the work substrate A part of the scattered solder scattered from the reflow soldering position of the part at that time is received by one surface of the shutter through the opening and prevents the solder from falling into the protection area by the shutter, and the parts of the reflow soldering positions scattered from the scattering of solder of said one surface of the part the shutter is received by the surface of the opposite side half to the protected area Characterized in that to prevent the fall by the shutter.
[0009]
In addition, at the timing when the substrate temperature exceeds the solder flux evaporation temperature and below the solder melting point temperature, the shutter and the work substrate move relative to each other so that the shutter covers the protection area and the one surface of the shutter It reduces the adhesion of the flux to the surface on the opposite side .
[0011]
In addition, an air flow is formed on the one surface side of the shutter, and the scattered solder that has passed through the opening is blown out or sucked off .
Further, the scattered solder adhering to the surface of the shutter facing the soldering surface of the work substrate is scraped and refreshed by relative movement of the shutter and the work substrate .
[0012]
In addition, an adhesive layer is formed on a surface opposite to the one surface of the shutter, and the scattered solder that has collided is captured by the adhesive layer.
In the reflow soldering apparatus of the present invention, the work board set in the heating device is located on the soldering surface side so as not to contact the mounting component, covers the protection area of the soldering surface, and is located at the position of the component. Correspondingly to the execution of the soldering temperature profile by the heating device, the shutter having a corresponding opening and the first position where the shutter covers the protection area of the soldering surface and the second position where the shutter does not cover the shutter. The shutter and driving means for moving the heating device relative to each other are provided.
[0013]
In addition , the driving unit is configured to move the shutter from the first position to the second position with respect to the work substrate set in the heating device.
[0014]
In addition, a scraper is provided that scrapes off the scattered solder adhering to the surface of the shutter facing the soldering surface of the work substrate by relative movement of the shutter and the work substrate.
Further, an adhesive layer facing the soldering surface of the work substrate of the shutter is formed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the reflow soldering method of the present invention will be described based on specific embodiments.
[0016]
(Embodiment 1)
1 to 3 show (Embodiment 1) of the present invention.
The reflow soldering apparatus is configured as shown in FIG.
[0017]
The work stage 1a is provided with a heating device 2a. The work stage 1b is provided with a heating device 2b. The work substrate 3 on which components are arranged by printing cream solder on the soldering location is placed on a loading slider 4a that moves in the direction of arrow A and is carried into the center of the apparatus from the right side of the apparatus. Then, the work substrate 3 is moved on the heating devices 2a and 2b by the pickup 5 along the direction of the arrow B in the drawing with the surface opposite to the soldering surface facing down.
[0018]
In the vicinity of the heating device 2a, a shutter 7a that is driven to open and close by the cylinder device 6a is provided over the position shown in FIG. 1A and the position shown in FIG. Also in the vicinity of the heating device 2b, a shutter 7b that is driven to open and close by the cylinder device 6b is provided over the position shown in FIG. 1A and the position shown in FIG. 8 is cream solder and 9 is a component.
[0019]
As shown in FIG. 1A, the work substrate 3 is set by the pickup 5 in a state where the shutter 7a is opened (the shutter 7a does not cover the soldering surface), and the soldering temperature profile is set by the heating device 2a. In the course of execution, the shutter 7a is closed as shown in FIG.
[0020]
The shutter 7a has an opening 10 corresponding to the position of the mounted component on the work board 3 as shown in FIG. 3, but the contact pattern 11 as a protection area of the soldering surface of the work board 3 is formed. The opening 10 is not provided in the upper position.
[0021]
For example, when the temperature of the work substrate 3 is raised by the heating device 2a in the state shown in FIG. 1B with the shutter 7a closed, when the cream solder 8 is lead-free, the cream has a temperature lower than the solder melting point 217 ° C. As a result of bumping of the solvent which is a component of the solder 8, the solder 12 having a diameter of about 20 μm to 40 μm scatters as shown in FIG. The amount of scattered solder that passes through the opening 10 of the shutter 7a and rests on the upper surface side of the shutter 7a and falls on the contact pattern 11 is reduced.
[0022]
Specifically, the solder scattering rate to the contact pattern 11 was 6.5% in the past, but after the countermeasure of this (Embodiment 1), the solder scattering rate was improved to 2.2%.
After the temperature of the solder melting point exceeds 217 ° C. or during the temperature decrease, the shutter 7a is retracted to the position shown in FIG. 1A, and the work substrate 3 is unloaded in the reverse route to the loading time. The shutter 7b is similarly driven.
[0023]
In this embodiment, the shutters 7a and 7b have arrived on the work substrate 3 from an early stage. However, in the case of lead-free solder, the state shown in FIG. More specifically, the shutters 7a and 7b are closed at the timing when the substrate temperature exceeds the solder flux evaporation temperature and below the solder melting point temperature, so that the back surfaces of the shutters 7a and 7b are creamed. It is less likely to come into contact with the flux component rising from the solder 8, and it is possible to reduce the adhesion of flux to the back surfaces of the shutters 7a and 7b and the phenomenon that the scattered solder 12 adheres to the adhered flux.
[0024]
Further, as shown in FIG. 2, a suction port 13 of an exhaust device for sucking and removing gas generated in the soldering process is opened above the closed shutter 7a and passes through the opening 10. A part of the scattered solder 12 is sucked and removed from the suction port 13. A suction port (not shown) of the exhaust device is similarly opened at a position above the shutter 7b.
[0025]
In the above embodiment, no special processing is formed on the back surfaces of the shutters 7a and 7b, but an adhesive layer is formed on the back surfaces of the shutters 7a and 7b so as to capture the scattered solder 12 that has collided. As a result, the solder scattering rate can be further reduced.
[0026]
(Embodiment 2)
FIG. 4 shows (Embodiment 2) of the present invention.
As seen in (Embodiment 1), the scattered solder 12a (see FIG. 4 (a)) adhering to the back surfaces of the shutters 7a and 7b falls on the work substrate 3 when the shutters 7a and 7b are opened and closed. However, in this (Embodiment 2), in the process of opening the shutters 7a and 7b, the scraper 14 is lowered so as not to contact the back surfaces of the shutters 7a and 7b as shown in FIG. 4B. Yes. Next, in the process of closing the shutters 7a and 7b, as shown in FIG. 4C, the scraper 14 is lifted so as to come into contact with the back surfaces of the shutters 7a and 7b, and the shutters 7a and 7b are closed in this state. And scrape off the adhered foreign matter.
[0027]
According to this configuration, even if the shutters 7a and 7b are provided, it is possible to prevent the foreign matter from falling along with the opening and closing of the shutters 7a and 7b.
In this embodiment, the scraper 14 is only moved up and down. However, the scraper 14 itself moves along the back surface of the work substrate 3 to scrape off foreign matter, or the scraper 14 and the shutters 7a and 7b are relative to each other. It can also be configured to scrape off foreign objects while moving.
[0028]
In each of the above embodiments, the shutters 7a and 7b are moved with respect to the work substrate 3. However, the heating device 2a and 2b are moved closer to the positions of the shutters 7a and 7b by the cylinder device 15 shown in FIG. Even if a state equivalent to b) is obtained, the solder scattering rate can be further reduced. In this case, the shutters 7a and 7b are fixed at the position shown in FIG. 1B, and the pickup is performed between the heating device 2a at the lowered position and the shutter 7a, and between the heating device 2b at the lowered position and the shutter 7b. 5 to carry in / out the work substrate 3.
[0029]
Further, even when the heating devices 2a and 2b on which the work substrate 3 is set are moved relative to the lower positions of the shutters 7a and 7b to obtain a state equivalent to FIG. 1B, the solder scattering rate can be further reduced.
[0030]
The relative movement refers to the shutter and the workpiece when the heating device on the work substrate side is stopped and the shutter is moved out, the shutter is stopped and the heating device on the work substrate 3 side is moved. This is a case where both of the heating devices on the substrate 3 side move.
[0031]
In each of the above-described embodiments, the air was only sucked from the suction port 13 of the exhaust device. However, air blown in the direction toward the suction port 13 was performed on the surface side of the shutters 7a and 7b, and the scattering that passed through the opening 10 was performed. It is also possible to reduce the solder scattering rate by configuring the solder 12 to be blown away by this air blowing.
[0032]
【The invention's effect】
As described above, according to the present invention, when the surface opposite to the soldering surface of the work substrate is heated and the components are reflow soldered and mounted on the soldering surface, the soldering surface side of the work substrate is mounted. a position not in contact with said component in said covers the protection area of the soldering surface so as to correspond to the position of the component is disposed a shutter opening formed, the soldering temperature profile by heating the work substrate A part of the scattered solder scattered from the reflow soldering position of the part at that time is received by one surface of the shutter through the opening and prevents the solder from falling into the protection area by the shutter, and the parts of the reflow soldering positions scattered from the scattering of solder of said one surface of the part the shutter is received by the opposite surface of the solder to the protected area Since impede down by the shutter, a portion of the solder scattered scattered from the reflow soldering position of the component, by receiving at the surface of the shutter through the opening, it can improve the solder scattering rate to the protected area.
[0033]
When the substrate temperature exceeds the solder flux evaporation temperature and below the solder melting point temperature, the shutter and the work substrate move relative to each other so that the shutter covers the protection area and the one surface of the shutter is The adhesion of flux to the opposite surface can be reduced.
[0035]
Further, by forming an air flow on the one front side of the shutter, you can improve the solder scattering rate to the protected area by blowing or blotting solder scattering passing through the aperture.
[0036]
In addition, the scattered solder adhering to the surface of the shutter facing the soldering surface of the work board is scraped and refreshed by the relative movement of the shutter and the work board, even though the shutter is provided. The fall of foreign matter to the protection area can be reduced.
[0037]
Further, an adhesive layer was formed on the front surface opposite to the one surface of the shutter, by capturing the scattered solder collided with an adhesive layer, can reduce the fall of foreign matter into the protective area.
[Brief description of the drawings]
FIG. 1 is a process diagram of (Embodiment 1) illustrating a reflow soldering method according to the present invention. FIG. 2 is a configuration diagram of a reflow soldering apparatus according to the embodiment. FIG. 4 is a process diagram of the second embodiment showing the reflow soldering method of the present invention.
3 Work substrate 2a Heating device 9 Component 11 Solder surface protection area 7a Shutter 8 Cream solder 10 Shutter 7a opening 12a Spattered solder 13 Exhaust device inlet 14 Scraper

Claims (9)

When mounting the component by reflow soldering to the soldering surface by heating the surface opposite to the soldering surface of the work substrate,
A shutter that covers a protective area of the soldering surface and has an opening corresponding to the position of the component at a position that does not contact the component on the soldering surface side of the work substrate,
The work substrate is heated to execute a soldering temperature profile, and at that time, a part of the scattered solder scattered from the reflow soldering position of the component is received by the one surface of the shutter through the opening to the protection area. The solder is prevented from falling by the shutter, and a part of the scattered solder scattered from the reflow soldering position of the component is received by the surface opposite to the one surface of the shutter, and the solder falls to the protection area. A reflow soldering method that prevents the shutter by the shutter. When the substrate temperature exceeds the solder flux evaporation temperature and below the solder melting point temperature, the shutter and the work substrate move relative to each other so that the shutter covers the protection area and the one surface of the shutter is The reflow soldering method according to claim 1, wherein adhesion of flux to the opposite surface is reduced. An air flow is formed on the one surface side of the shutter to blow or suck the scattered solder that has passed through the opening.
The reflow soldering method according to claim 1 . The scattered solder adhering to the surface of the shutter facing the soldering surface of the work substrate is scraped and refreshed by the relative movement of the shutter and the work substrate.
The reflow soldering method according to claim 1 . The reflow soldering method according to claim 1 , wherein an adhesive layer is formed on a surface opposite to the one surface of the shutter, and the scattered solder that has collided is captured by the adhesive layer . A heating device for heating the work substrate from a surface opposite to the soldering surface of the work substrate;
A shutter which is in a position where it does not come into contact with a mounting component on the side of the soldering surface of the work substrate set in the heating device, covers the protection area of the soldering surface, and has an opening corresponding to the position of the component When,
Driving the shutter and the heating device relative to each other in synchronization with execution of a soldering temperature profile by the heating device between a first position where the shutter covers the protection area of the soldering surface and a second position where the shutter does not cover the protection area. Means and
A reflow soldering device. The drive means is configured to move the shutter from a first position to a second position with respect to a work substrate set in the heating device.
The reflow soldering apparatus according to claim 6 . A scraper for scraping scattered solder adhering to a surface of the shutter facing the soldering surface of the work substrate by relative movement of the shutter and the work substrate is provided.
The reflow soldering apparatus according to claim 6 . An adhesive layer was formed on the surface of the shutter facing the soldering surface of the work substrate.
The reflow soldering apparatus according to claim 6 .

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