JP3045132B2 - Reflow equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus for mounting an electronic component on a substrate by soldering.

[0002]

2. Description of the Related Art A conventional reflow apparatus includes a plurality of furnaces provided with heaters and a conveyor for sequentially transferring substrates to which electronic components are soldered to each furnace. . In such a reflow apparatus, the substrate is heated to an appropriate temperature by sequentially moving the substrate through each furnace by the conveyor, the solder is melted, and the electronic components are soldered. Further, in the conventional reflow apparatus, a blower for air circulation is provided in each furnace in order to make the temperature distribution in the furnace uniform.

In a conventional reflow apparatus, depending on conditions such as the size, material, layer structure, and pattern arrangement of a board to which electronic components are to be soldered, the board expands due to heat at the time of soldering and warps. May occur and may be deformed. Therefore, when mounting the board on the unit, the terminal part of the board cannot be inserted into the connector on the unit side, or even if it can be inserted, there is a poor connection at the connection part between the connector on the unit side and the board terminal part. Problems with the mechanical interface.

Therefore, conventionally, in order to prevent the substrate from being warped, the set temperature of each furnace is changed for each substrate having a different size or material, or the design of the substrate is changed. Was. Also, as shown in FIG. 5, a warp prevention jig 103 is fixed around the substrate 101 on which the electronic component 102 is mounted, and the rigidity of the substrate 101 is increased to prevent the substrate 101 from being warped. Was.

[0005]

However, even when the rigidity of the substrate is increased by using the warp preventing jig as described above, the only thing that can be fixed by the warp preventing jig is the periphery of the substrate. It was difficult to eliminate the warpage generated near the center. Further, in this case, the heat of the heated substrate is taken by the warpage prevention jig, so that there is a problem that unevenness in the temperature of the substrate occurs and soldering failure occurs near the warpage prevention jig. Further, the warp prevention jig must be attached and detached before and after the soldering step on the substrate, and there is a problem that the soldering step requires a large number of work steps.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflow apparatus capable of preventing the substrate from being warped when an electronic component is soldered to the substrate over the entire surface of the substrate.

[0007]

In order to achieve the above object, a reflow apparatus according to the present invention comprises a stage on which a substrate on which an electronic component to be mounted by soldering is mounted is mounted on an upper surface, and a stage for heating the substrate. A plurality of suction holes penetrating from the upper surface to the lower surface of the stage are provided on the entire surface of the stage, and an opening of the suction hole on the lower surface of the stage is provided. And a suction means for sucking air from the device.

In the reflow apparatus configured as described above, when the suction means is operated, the air between the substrate placed on the upper surface of the stage and the upper surface of the stage is sucked from the suction hole, and the substrate is removed from the stage. Adsorbed on the upper surface. Thus, the substrate is restrained and held on the upper surface of the stage, so that deformation of the substrate due to heater heating for soldering the electronic component to the substrate is prevented over the entire surface of the substrate.

The suction means includes a closed space forming means surrounding the lower surface of the stage to form a closed space, and a negative pressure generating means for making the inside of the closed space a negative pressure with respect to the atmospheric pressure. When the negative pressure generating means is operated, the closed space becomes a negative pressure with respect to the atmospheric pressure, and air between the substrate mounted on the upper surface of the stage and the upper surface of the stage is sucked from the suction hole. Then, the substrate is attracted to the upper surface of the stage over the entire surface. Further, the heater is arranged above the substrate placed on the upper surface of the stage and below the suction means, so that the suction holes provided on the stage 4 are covered with the substrate. In the suction holes that are not provided, air is ventilated from the upper surface to the lower surface of the stage. Thereby, the air in the furnace is circulated and the temperature distribution in the furnace is made uniform, so that occurrence of soldering failure due to overheating or insufficient heating of the substrate is prevented.

[0010] The suction means may be a duct passing under the stage and having both ends opened into the furnace.
A duct in which a portion passing below the stage has an inner diameter smaller than an inner diameter near the opening at both ends, and a suction hole communicating with a portion passing below the stage; When the air supply means is operated, air is supplied into the duct from one opening of the duct, and the air is supplied from the other opening. It is discharged outside the duct. Since the duct has a smaller inside diameter at the part passing under the stage than the other part, when the air passes through that part, the flow velocity of the air becomes faster than the flow velocity at the other part, and that part The internal pressure of the interior decreases. As a result, air between the substrate placed on the stage and the upper surface of the stage is sucked from the suction hole, and the substrate is adsorbed on the upper surface of the stage over the entire surface.

Further, the heater is disposed near one opening of the duct, and the air supply means is disposed near the other opening of the duct. The heated air circulates through the furnace,
Since the temperature distribution in the furnace is made uniform, occurrence of poor soldering due to overheating or insufficient heating of the substrate is prevented.

Further, the above-mentioned reflow apparatus may be configured such that a plurality of the furnaces are provided and a conveyor for sequentially transporting the substrates to the respective furnaces is provided.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a perspective view showing a first embodiment of a reflow apparatus according to the present invention, with a part thereof cut away.
FIG. 2 is a sectional view taken along line AA of the reflow apparatus shown in FIG.

The reflow apparatus 1 of the present embodiment has a plurality of furnaces 1a partitioned by walls 1b and having different temperature settings. However, FIG. 1 shows only one furnace 1a in the reflow apparatus 1. Further, the reflow device 1 is provided with a conveyor 7 for sequentially transporting the substrate 2 to which the electronic components 3 are soldered to each furnace 1a. Substrate 2
Is sequentially transferred to each furnace 1a while being placed on the upper surface of the stage 4.

Further, in each furnace 1a, heaters 6 for heating the substrate 2 are arranged at regular intervals above and below the transport path of the substrate 2 by the conveyor 7. The heaters 6 disposed above the transport path of the substrate 2 and the heaters 6 disposed below the transport path of the substrate 2 are disposed so as to face each other.

As shown in FIG. 2, the stage 4 has a plurality of suction holes 4a penetrating from the upper surface to the lower surface of the stage 4.
Are provided in a mesh pattern on the entire surface of the stage 4. A cover 8 as a closed space forming means for forming a closed space 8a surrounding the lower surface of the stage 4 is provided below the stage 4.
Is provided. Further, a blower 5 is provided below the cover 8. The blower 5 has a function of circulating the air in the furnace 1a, as well as a function as a negative pressure generating unit that sucks air in the closed space 8a to create a negative pressure in the closed space 8a. The cover 8 and the blower 5 constitute suction means for sucking air from the suction hole 4a of the stage 4.

Next, the operation of the above-described reflow apparatus 1 of the present embodiment will be described. In the reflow apparatus 1 configured as described above, when the stage 4 is mounted on the conveyor 7, the power of the blower 5 is turned on, and the fan of the blower 5 rotates. Then, the air in the closed space 8a is sucked, and the inside of the closed space 8a becomes a negative pressure with respect to the atmospheric pressure. When the inside of the closed space 8a becomes negative pressure, air between the substrate 2 placed on the stage 4 and the upper surface of the stage 4 is sucked from the suction holes 4a, and the substrate 2 is adsorbed on the stage 4 over the entire surface. .

In this state, each furnace 1 heated by the heater 6
When the substrate 2 is conveyed by the conveyor 7 in the area a, the substrate 2 is heated to an appropriate temperature, the solder is melted, and the electronic component 3 is soldered. The substrate 2 has a size, a material, a layer structure,
Since the thermal expansion coefficient of each part is non-uniform due to various conditions such as the pattern arrangement and the like, when heated, it warps and tends to deform. However, since the substrate 2 is adsorbed on the stage 4 and is restrained and held over the entire surface as described above, it is possible to prevent the substrate 2 from being deformed.

As described above, the reflow device 1 of the present embodiment
According to this, it is possible to prevent deformation due to warpage not only around the substrate 2 but also over the entire surface, as compared with the case where a warpage prevention jig is used as in the prior art. Further, in this embodiment, since the warpage prevention jig is not used, the heat of the heated substrate is not taken away by the warpage prevention jig, and the substrate does not have uneven temperature and no soldering failure occurs. Therefore, the reliability of the substrate 2 on which the electronic components 3 are mounted can be improved. In addition, since it is not necessary to attach and detach the warp prevention jig, the number of work steps in the soldering process can be reduced.

Further, in the reflow apparatus 1 of the present embodiment,
When the air in the closed space 8a is sucked by the blower 5,
In the suction holes 4 a of the stage 4 that are not covered with the substrate 2, air flows from the upper surface of the stage 4 to the lower surface. Thereby, the air in the furnace 1a is circulated and the temperature distribution in each furnace 1a can be made uniform, so that occurrence of soldering failure due to overheating or insufficient heating of the substrate 2 can be prevented. Since the blower 5 also has a function as a negative pressure generating means as described above, the suction of the substrate 2 onto the stage 4 and the air circulation can be performed at the same time. As compared with the case where the blower is used, space saving and effective use of the power source in the reflow device 1 can be achieved.

(Second Embodiment) FIG. 3 is a perspective view showing a second embodiment of the reflow apparatus according to the present invention, with a part thereof cut away.
FIG. 4 is a sectional view of the reflow device shown in FIG.

The reflow apparatus 11 of this embodiment is constituted by one furnace 11a. The substrate 12 to which the electronic component 13 is to be soldered is placed in a furnace 11a.
A conveyor 17 is provided for transporting the inside.

As shown in FIG. 4, a stage 14 on which the substrate 12 conveyed by the conveyer 17 is placed at a desired position below the conveying path of the substrate 12 by the conveyer 17.
Has been fixed. The stage 14 is provided with a plurality of suction holes 14 a penetrating from the upper surface to the rear surface of the stage 14 in a mesh shape over the entire surface of the stage 14.

The reflow device 11 has a stage 1
4, an opening is formed on both sides of the conveyor 17, and a duct 18 opened in the reflow device 11 a is provided. The duct 18 is provided such that the inner diameter of the constricted portion 18a passing below the stage 14 is smaller than the inner diameter near both openings. The suction hole 14a of the stage 14 communicates with the narrowed portion 18a of the duct 18.

Further, a heater 16 for heating the substrate 12 is provided near one opening of the duct 18, and air is supplied into the duct 18 near the other opening of the duct 18. Blower 15 is provided as an air supply means for the air supply. In the reflow device 11 of the present embodiment,
Narrowed portion 18a and blower 15 provided in duct 18
Thereby, a suction unit for sucking air from the suction hole 14a of the stage 14 is configured.

Next, the operation of the above-described reflow apparatus 11 of the present embodiment will be described.

The reflow device 11 configured as described above
Then, the substrate 12 is transported by the conveyor 17 and placed on the stage 14. Then, the detection means (not shown) detects that the substrate 12 has been placed on the stage 14, and the rotation of the fan of the blower 15 is started.
When the blower 15 rotates, the air heated by the heater 16 is sucked into the duct 18 from the opening on the heater 16 side,
After passing through the narrowed portion 18a, the air is discharged from the opening on the blower 15 side to the outside of the duct 18. The air discharged to the outside of the duct 18 is sucked into the duct 18 again, and
a, the temperature in the furnace 11a is heated to an appropriate temperature.

Since the flow path of the duct 18 is narrow at the narrowed portion 18a, when the air passes through the duct 18, the flow velocity of the air in the narrowed portion 18a is higher than the flow velocity in the other portions. As a result, the air pressure in the narrowed portion 18a decreases. As a result, the substrate 1 placed on the stage 14
The air between the substrate 2 and the upper surface of the stage 14 is sucked from the suction hole 14a, and the substrate 12 is sucked to the stage 14 over the entire surface.

In this state, the substrate 12 is heated to an appropriate temperature by the air heated by the heater 16, the solder is melted, and the electronic component 13 is soldered. The substrate 12 has a non-uniform coefficient of thermal expansion depending on various conditions such as size, material, layer structure, pattern arrangement, etc., and therefore, when heated, it warps and tends to deform. Therefore, the substrate 12 can be prevented from being deformed because it is adsorbed and held on the stage 14 for a period of time.

When the soldering process of the electronic component 13 is completed, the rotation of the fan of the blower 15 stops and the stage 14
The suction of the substrate 12 on the upper side is released. Thereafter, the conveyor 17 is operated again, and the substrate 12 is moved to the reflow device 11.
Transported to the outside.

In the reflow apparatus 11 of this embodiment, too, the air in the furnace 11a is circulated by the blower 15, the temperature distribution in the furnace 11a becomes uniform, and the soldering failure due to overheating or insufficient heating of the substrate 12 is performed. Can be prevented from occurring. Further, since the suction of the substrate 12 on the stage 14 and the air circulation can be performed simultaneously by the blower 15, the space in the reflow device 11 can be saved and the power source can be effectively used. Also, in the present embodiment, since the warpage prevention jig is not used, it is possible to prevent the occurrence of soldering failure due to uneven temperature of the substrate, and to reduce the number of work steps in the soldering process. it can.

[0033]

As described above, in the reflow apparatus of the present invention, a plurality of suction holes penetrating from the upper surface to the lower surface of the stage are provided on the entire surface of the stage on which the substrate is mounted.
Further, since suction means for sucking air from the opening of the suction hole on the lower surface of the stage is provided, the substrate is restrained and held on the upper surface of the stage over the entire surface, and the electronic component is soldered to the substrate. Deformation of the substrate due to heating by the heater can be prevented over the entire surface of the substrate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a reflow apparatus according to the present invention, with a part thereof cut away.

FIG. 2 is a cross-sectional view of the reflow device shown in FIG. 1, taken along line AA.

FIG. 3 is a perspective view showing a second embodiment of the reflow apparatus of the present invention, with a part thereof cut away.

FIG. 4 is a cross-sectional view of the reflow apparatus shown in FIG. 3, taken along line BB.

FIG. 5 is a perspective view showing a substrate according to the related art in which a warp prevention jig is fixed around.

[Explanation of symbols]

 1,11 Reflow device 1a, 11a Furnace 1b Wall 2,12 Substrate 3,13 Electronic component 4,14 Stage 4a, 14a Suction hole 5,15 Blower 6,16 Heater 7,17 Conveyor 8 Cover 8a Closed space 18 Duct 18a Narrowing Department

Claims (6)

(57) [Claims] 1. A reflow apparatus in which a stage on which a substrate on which an electronic component mounted by soldering is mounted is mounted on a top surface and a heater for heating the substrate is provided in a furnace. A plurality of suction holes penetrated from the upper surface to the lower surface of the stage are provided on the entire surface, and suction means for suctioning air from the opening of the suction hole on the lower surface of the stage is provided. Reflow equipment. 2. The suction means comprises: closed space forming means surrounding a lower surface of the stage to form a closed space; and negative pressure generating means for generating a negative pressure in the closed space with respect to atmospheric pressure. The reflow apparatus according to claim 1. 3. The reflow apparatus according to claim 2, wherein the heater is disposed above the substrate placed on the upper surface of the stage and below the suction unit. 4. The suction means is a duct that passes under the stage and has both ends opened into the furnace, and has an inner diameter of a portion that passes below the stage than an inner diameter near the opening at both ends. 2. The duct according to claim 1, further comprising: a duct having a smaller size, a duct in which the suction hole is communicated with a portion passing below the stage, and an air feeding unit for feeding air into the duct. 3. Reflow device. 5. The reflow apparatus according to claim 4, wherein the heater is provided near one opening of the duct, and the air supply means is provided near the other opening of the duct. 6. A plurality of said furnaces are provided,
The reflow apparatus according to any one of claims 1 to 5, further comprising a conveyor for sequentially transporting the substrate to each of the furnaces.