JP2004253491A - Reflow soldering method and reflow soldering equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflow soldering method in which foreign matters can be prevented from scattering to a protective area on a work substrate without providing a wall for preventing adhesion of foreign matter on the work substrate side. <P>SOLUTION: A shutter 7a is disposed at a position not touching a component 9 on the work substrate in correspondence with the protective area 11 of a soldering surface. Soldering temperature profile is then practiced by heating the substrate 3 and the solder scattered from reflow soldering position to the protective area 11 is prevented from falling by means of the shutter 7a thus improving scattering rate of solder. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflow soldering method that can reduce the influence of scattered solder generated during reflow soldering.
[0002]
[Prior art]
When reflow soldering components to a surface mount board, which is a work board, the solvent contained in the cream solder bumps as the work board is heated, causing a part of the flux or a small flux of 20 μm to 40 μm. A situation occurs in which the solder having the particle size scatters around the soldering portion.
[0003]
In the case where a contact pattern is located around a soldering point like a surface mount board of a mobile phone device, a defective contact occurs when scattered flux or solder balls adhere to the contact pattern.
[0004]
Therefore, in the related art, a foreign matter adhesion preventing wall 60 having a predetermined height is formed on a soldering surface of a work board so as to surround a contact pattern, as shown in Patent Document 1, so that foreign matter 50 scattered during reflow soldering can be reduced. It is configured to stave off.
[0005]
[Patent Document 1]
JP-A-07-283493 (FIG. 1)
[0006]
[Problems to be solved by the invention]
However, in the conventional method of providing the foreign matter adhesion preventing wall 60 on the side of the work board, in the case of a mobile phone device incorporating such a work board, the board becomes thick and the product becomes thick, which is not preferable.
[0007]
An object of the present invention is to provide a reflow soldering method capable of preventing scattering of foreign matter during reflow soldering to a protection area on a work board without providing a foreign matter adhesion preventing wall on the work board side.
[0008]
[Means for Solving the Problems]
According to the reflow soldering method of the present invention, when mounting a component by reflow soldering on a soldering surface of a substrate, a shutter is arranged at a position not in contact with the component on a work in correspondence with a protection area of the soldering surface. The work board is heated to perform a soldering temperature profile, and at this time, the shutter prevents the solder scattered from the reflow soldering position of the component from falling into the protection area.
[0009]
Further, at a timing when the substrate temperature is higher than the evaporation temperature of the solder flux and lower than 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 moves to the back surface of the shutter. It is characterized in that flux adhesion is reduced.
[0010]
Further, the shutter has an opening formed corresponding to the position of the soldering component, and receives a part of the scattered solder scattered from the reflow soldering position of the component on the surface of the shutter through the opening. It is characterized.
[0011]
Further, an air flow is formed on the front surface side of the shutter to blow or suck out the scattered solder that has passed through the opening.
Further, it is characterized in that the scattered solder adhered to the back surface of the shutter is scraped and refreshed when the shutter and the work substrate are relatively moved.
[0012]
Further, an adhesive layer is formed on the back surface of the shutter, and the scattered scattered solder is captured by the adhesive layer.
The reflow soldering apparatus according to the present invention includes a heating device that heats the work substrate from a surface opposite to a soldering surface of the work substrate, and a heating device that is located at a position that does not contact a mounted component of the work substrate set in the heating device. A shutter that covers the protection area of the soldering surface and 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, in synchronization with the execution of the soldering temperature profile by the heating device. And a driving means for relatively moving the shutter and the heating device.
[0013]
Further, an opening formed corresponding to the position of the mounted component is formed in the shutter covering the protection area of the soldering surface.
Further, the driving 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.
[0014]
Further, a scraper for scraping off the scattered solder attached to the back surface of the shutter by the relative movement between the shutter and the work board is provided.
Further, an adhesive layer is formed on the back surface of the shutter.
[0015]
BEST MODE FOR CARRYING OUT 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 board 3 on which components are arranged by printing cream solder on the soldering positions is placed on a carry-in slider 4a that moves in the direction of arrow A, and carried into the center of the machine from the right side of the machine. Then, the work board 3 is moved by the pickup 5 onto the heating devices 2a and 2b along the direction of the arrow B in the drawing, with the surface opposite to the soldering surface facing downward.
[0018]
In the vicinity of the heating device 2a, a shutter 7a that is opened and closed by a cylinder device 6a is provided between the position shown in FIG. 1A and the position shown in FIG. 1B. A shutter 7b, which is opened and closed by a cylinder device 6b, is also provided near the heating device 2b over a position shown in FIG. 1A and a position shown in FIG. 1B. 8 is a cream solder and 9 is a component.
[0019]
As shown in FIG. 1A, the work board 3 is set by the pickup 5 in a state where the shutter 7a is opened (a state where the shutter 7a does not cover the soldering surface), and the soldering temperature profile is set by the heating device 2a. During the execution process, 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 of 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 at an upper position.
[0021]
For example, when the temperature of the work board 3 is increased by the heating device 2a in the state of FIG. 1B with the shutter 7a closed, when the cream solder 8 is lead-free, the cream is melted at a temperature lower than the solder melting point 217 ° C. As a result, bumping of the solvent which is a component of the solder 8 occurs, and 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 is placed 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 this measure (Embodiment 1), the solder scattering rate was improved to 2.2%.
During or after the temperature falls below the solder melting point of 217 ° C., the shutter 7a is retracted to the position shown in FIG. 1A, and the work substrate 3 is carried out by a route reverse to that at the time of carrying in. 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 a timing when the substrate temperature is higher than the evaporation temperature of the solder flux and lower than 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 the flux to the back surfaces of the shutters 7a and 7b and the phenomenon that the scattered solder 12 adheres to the attached flux.
[0024]
Further, as shown in FIG. 2, a suction port 13 of an exhaust device for sucking and removing gas and the like generated in a soldering process is opened at a position above the shutter 7a in a closed state. A part of the scattered solder 12 sucked from the suction port 13 is removed. A suction port (not shown) of the exhaust device is similarly opened above the shutter 7b.
[0025]
In the above embodiment, no special processing is formed on the back surfaces of the shutters 7a and 7b. However, an adhesive layer is formed on the back surfaces of the shutters 7a and 7b to capture the scattered scattered solder 12. This can further reduce the solder scattering rate.
[0026]
(Embodiment 2)
FIG. 4 shows (Embodiment 2) of the present invention.
As seen in (Embodiment 1), the scattered solder 12a (see FIG. 4A) attached to the back surfaces of the shutters 7a and 7b falls onto the work substrate 3 when the shutters 7a and 7b are opened and closed. In this (Embodiment 2), in the process of opening the shutters 7a and 7b as shown in FIG. 4B, the scraper 14 descends so as not to contact the back surfaces of the shutters 7a and 7b. I have. Next, in the process of closing the shutters 7a and 7b, as shown in FIG. 4C, the scraper 14 is raised so as to contact the back surfaces of the shutters 7a and 7b, and the shutters 7a and 7b are closed in this state. Then, the attached foreign matter is scraped off.
[0027]
According to this configuration, it is possible to prevent foreign matter from dropping due to opening and closing of the shutters 7a and 7b despite the provision of the shutters 7a and 7b.
In this embodiment, the scraper 14 only moves up and down. However, the scraper 14 itself moves along the back surface of the work substrate 3 to scrape foreign substances, or the scraper 14 and the shutters 7a and 7b It can also be configured to scrape foreign matter while moving.
[0028]
In each of the above-described embodiments, the shutters 7a and 7b have moved with respect to the work substrate 3, but the heating devices 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 positions shown in FIG. 1B, and the pickup is picked up 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. The loading and unloading of the work substrate 3 by the step 5 is performed.
[0029]
Further, even if the heating devices 2a and 2b on which the work substrate 3 is set are relatively moved to positions below the shutters 7a and 7b to obtain a state equivalent to FIG. 1B, the solder scattering rate can be further reduced.
[0030]
Note that the relative movement means that when the heating device on the side of the work substrate is stopped and the shutter moves in and out, the shutter is stopped and the heating device on the side of the work substrate 3 moves, and the shutter and the work are moved. This is the case where both the heating devices on the side of the substrate 3 move.
[0031]
In each of the above-described embodiments, air is merely sucked from the suction port 13 of the exhaust device. However, air is blown toward the suction port 13 on the front surface side of the shutters 7a and 7b, and the scattered air passing through the opening 10 is formed. It is also possible to reduce the solder scattering rate by configuring the solder 12 to be blown off by the blowing.
[0032]
【The invention's effect】
As described above, according to the present invention, a shutter is provided at a position spaced from the soldering surface of the work and not in contact with the component, corresponding to the protection area of the soldering surface, and heating the work substrate. In this case, the soldering temperature profile is executed, and at this time, the parts prevent the components from scattering from the reflow soldering position and falling into the protection area by the shutter, so that the solder scattering rate to the protection area can be improved.
[0033]
At a timing when the substrate temperature is higher than the evaporation temperature of the solder flux and lower than the solder melting point temperature, the shutter and the work substrate relatively move to cover the protection area so that the shutter covers the protection area and the flux to the back surface of the shutter. Adhesion can be reduced.
[0034]
The shutter has an opening formed corresponding to the position of the soldering component, by receiving a part of the scattered solder scattered from the reflow soldering position of the component on the surface of the shutter through the opening, The solder scattering rate to the protection area can be improved.
[0035]
Further, by forming an air flow on the front surface side of the shutter and blowing or sucking out the scattered solder that has passed through the opening, it is possible to improve the rate of scattered solder to the protection area.
[0036]
Also, by scattering and splashing the scattered solder adhered to the back surface of the shutter during the relative movement of the shutter and the work board, foreign matter can be prevented from falling into the protection area despite the provision of the shutter. Can be reduced.
[0037]
In addition, by forming an adhesive layer on the back surface of the shutter and catching the scattered scattered solder with the adhesive layer, it is possible to reduce the fall of foreign matter to the protection area.
[Brief description of the drawings]
FIG. 1 is a process diagram showing a reflow soldering method according to the present invention (Embodiment 1); FIG. 2 is a configuration diagram of a reflow soldering apparatus according to the embodiment; FIG. FIG. 4 is a process diagram (second embodiment) showing a reflow soldering method of the present invention.
3 Work board 2a Heating device 9 Parts 11 Protected area 7a for soldering surface 7a Shutter 8 Cream solder 10 Opening 12a of shutter 7a Scattered solder 13 Suction port of exhaust device 14 Scraper

Claims (11)

When mounting components by reflow soldering on the soldering surface of the work board,
At a position not in contact with the component on the work board, a shutter is provided corresponding to the protection area of the soldering surface,
A reflow soldering method in which the work substrate is heated to execute a soldering temperature profile, and at this time, the shutter prevents the solder scattered from the reflow soldering position of the component from dropping into the protection area. At a timing when the substrate temperature is higher than the evaporation temperature of the solder flux and lower than the solder melting point temperature, the shutter and the work substrate relatively move to cover the protection area so that the shutter covers the protection area and the flux to the back surface of the shutter. The reflow soldering method according to claim 1, wherein the adhesion is reduced. 2. The shutter according to claim 1, wherein the shutter has an opening formed corresponding to a position of the soldered component, and receives a part of the scattered solder scattered from a reflow soldering position of the component on the surface of the shutter through the opening. Alternatively, the reflow soldering method according to claim 2. 4. The reflow soldering method according to claim 3, wherein an air flow is formed on the front side of the shutter to blow or suck off the scattered solder passing through the opening. The reflow soldering method according to claim 1, wherein the scattered solder attached to the back surface of the shutter is scraped and refreshed when the shutter and the work board are relatively moved. 2. The reflow soldering method according to claim 1, wherein an adhesive layer is formed on a back surface of the shutter, and the scattered scattered solder is captured by the adhesive layer. A heating device for heating the work substrate from a surface opposite to a soldering surface of the work substrate,
A shutter that is located at a position where it does not come into contact with a mounted component of the work board set in the heating device and covers the protection area of the soldering surface;
A drive that relatively moves the shutter and the heating device between a first position where the shutter covers the protection area of the soldering surface and a second position that does not cover the protection region in synchronization with execution of a soldering temperature profile by the heating device; Reflow soldering apparatus provided with means. 8. The reflow soldering apparatus according to claim 7, wherein an opening formed corresponding to the position of the mounted component is formed in the shutter covering the protection area of the soldering surface. 8. The reflow soldering apparatus according to claim 7, wherein the driving unit is configured to move the shutter from a first position to a second position with respect to the work substrate set in the heating device. 8. The reflow soldering apparatus according to claim 7, further comprising a scraper for scraping the scattered solder attached to the back surface of the shutter by a relative movement between the shutter and the work board. The reflow soldering apparatus according to claim 7, wherein an adhesive layer is formed on a back surface of the shutter.

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