JP2015015403A - Reflow device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflow device which makes it possible to shorten a treatment time, and to reduce an amount of consumption of a reduction gas.SOLUTION: A reflow device arranged to reduce an oxide film of solder while heating a work 1 with the solder comprises: a reduction chamber 4 for performing a reduction treatment on the work 1; a preceding-stage chamber 11 connected in a preceding stage for the reduction chamber 4; a following stage chamber 12 connected in a following stage for the reduction chamber 4; a reduction gas supply mechanism unit 70 for supplying a reduction gas into the reduction chamber 4; a heating mechanism unit 9 for heating the reduction gas; and a circulation path 6 for bringing the reduction gas out of the reduction chamber 4 and again bringing back into the reduction chamber 4.

Description

  The present invention relates to a reflow apparatus that heats a workpiece in a reducing atmosphere to reduce an oxide film on the surface of a solder, and in particular to reduce processing time and reducing gas consumption.

  A conventional reflow apparatus heats a workpiece in a chamber having a reducing atmosphere, reduces solder and an oxide film on the surface of another portion, and then raises the temperature to a solder melting temperature to perform solder bonding. And a work conveyance mechanism, a reduction chamber having a heater and a cooler, a tank, an atmosphere introduction chamber for introducing a reduction atmosphere into the reduction chamber, and an exhaust device for exhausting the atmosphere in the reduction chamber. And the workpiece | work mounted in the tray is sent into the reduction chamber filled with the inert gas from the carrying-in part. After exhausting the inert gas in the chamber, a reducing gas is supplied to replace the reducing atmosphere, and the workpiece is heated with a heater. The workpiece is solder-bonded in a state where the solder and the oxide film on the surface of another portion are reduced. Thereafter, the reducing atmosphere is discharged and the inside of the reducing chamber is again replaced with an inert gas, and then the workpiece is cooled. After cooling is completed, the work is carried out of the chamber (see, for example, Patent Document 1).

JP 2001-244618 A

  In the conventional reflow apparatus, it is necessary to heat the inside of the chamber in a reducing atmosphere in order to remove the solder and the oxide film on the other surface. Further, when the work is carried into and out of the chamber, the inside and outside of the chamber are spatially connected, so that the atmosphere enters and leaves. However, it is not desirable to release the carboxylic acid or hydrogen used as the reducing agent into the atmosphere as it is harmful to the human body or because of the danger of explosion when mixed with oxygen. Therefore, when the space inside and outside the chamber is connected, it is necessary to replace the inside of the chamber with a harmless atmosphere such as an inert gas.

  When the conventional method is used, it is necessary to replace the atmosphere in the chamber twice (inert gas atmosphere → reducing atmosphere, reducing atmosphere → inert gas atmosphere) every time a work for one tray is processed. Therefore, in addition to the time required for heating and reducing and soldering the work, extra time is required to replace the atmosphere in the chamber. Therefore, there is a problem that the processing time per work for one tray becomes long.

  Furthermore, since the exhaust is performed every time the atmosphere in the chamber is replaced, it is necessary to newly create a reducing atmosphere corresponding to the chamber capacity every time a work for one tray is processed. For this reason, there is a problem that the consumption of the reducing agent increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a reflow device capable of reducing the processing time and reducing the consumption of reducing gas.

The reflow device of this invention is
In the reflow apparatus for reducing the oxide film of the solder while heating the workpiece having solder,
A reduction chamber for performing a reduction treatment of the workpiece;
A front chamber connected to a front stage of the reduction chamber;
A rear chamber connected to a subsequent stage of the reduction chamber;
A reducing gas supply mechanism for supplying a reducing gas to the reducing chamber;
A heating mechanism for heating the reducing gas;
And a circulation path for taking out the reducing gas out of the reducing chamber and returning it back into the reducing chamber.

Since the reflow device of the present invention is configured as described above,
The processing time can be shortened and the consumption of reducing gas can be reduced.

It is a figure which shows the structure of the reflow apparatus of Embodiment 1 of this invention. It is a figure which shows the structure of the other reflow apparatus of Embodiment 1 of this invention. It is a figure which shows the structure of the reflow apparatus of Embodiment 2 of this invention. It is a figure which shows the structure of the other reflow apparatus of Embodiment 2 of this invention. It is a figure which shows the structure of the reflow apparatus of Embodiment 3 of this invention. It is a figure which shows the structure of the other reflow apparatus of Embodiment 3 of this invention.

Embodiment 1 FIG.
Embodiments of the present invention will be described below. FIG. 1 is a diagram showing a configuration of a reflow apparatus according to Embodiment 1 of the present invention. In the figure, a reflow apparatus includes a tray 2 that holds and loads a workpiece 1, a reduction chamber 4 for performing reduction processing of the workpiece 1, a front chamber 11 that is connected to the preceding stage of the reduction chamber 4, and a reduction chamber In order to move the rear chamber 12 connected to the rear stage of the chamber 4 and the tray 2 on which the workpiece 1 is mounted into and out of the chambers 4, 11, 12, for example, a conveyor system or a claw movable on the tray 2 in the transport direction is provided. A conveyance mechanism unit 3 configured by a method of hanging and feeding to the downstream side, and a cooling mechanism unit 13 for cooling the workpiece 1 provided in the rear chamber 12 are provided.

  Further, the doors 14a, 14b, 14c, and 14d provided at the loading / unloading ports of the chambers 4, 11, and 12 that are opened and closed when the workpiece 1 is transported, and a reducing gas in the reducing chamber 4, such as carboxylic acid or hydrogen. As a inert gas into each chamber 11, 12, for example, a reducing gas supply mechanism 70 for supplying the heating gas, a heating mechanism 9 formed by a hot plate having a coil heater for heating the reducing gas, An inert gas supply mechanism 15 for supplying nitrogen gas, argon gas, etc., a decompression mechanism 16 formed by a vacuum pump for exhausting the atmosphere in the chambers 11 and 12, and a decompression mechanism 16 connected to the decompression mechanism 16 And a reducing gas recovery mechanism unit 17 that recovers the reducing gas exhausted by the mechanism unit 16.

  Further, the reducing gas is taken out of the reducing chamber 4 and returned to the reducing chamber 4 again. The circulation path 6 formed from the forward path 6a and the return path 6b, and the atmosphere formed in the circulation path 6 in the reducing chamber 4 And a sub-chamber 5 connected in the middle of the circulation path 6. Note that a plurality of or a plurality of fans 10 may be formed in the circulation path 6.

  The reducing gas supply mechanism 70 is connected to the sub chamber 5. The heating mechanism unit 9 is disposed in the sub chamber 5 and is configured to heat the solder bonding process of the workpiece 1 in the reduction chamber 4. Further, the reducing gas supply mechanism unit 70 supplies the reducing agent 71 to the heating mechanism unit 9 in the sub-chamber 5, and the reducing agent 71 is heated and vaporized in the sub-chamber 5 to generate the reducing gas, and the circulation path 6. For example, the tank 7 is provided with a reducing agent 71 and a mass flow controller 8 for adjusting the supply amount of the reducing agent 71 in the tank 7. The volume of the sub chamber 5 is formed to be the same as or larger than the volume of the reduction chamber 4.

  Next, the operation of the reflow apparatus of the first embodiment configured as described above will be described. First, in the initial state, the reduction chamber 4 and the sub-chamber 5 are in a reducing atmosphere, and the chambers 11 and 12 are evacuated by the decompression mechanism 16 and then the inert gas is supplied by the inert gas supply mechanism 15. Supply an inert gas atmosphere. In this case, the reducing chamber 4 and the reducing atmosphere in the sub-chamber 5 are supplied by supplying a predetermined amount of liquid reducing agent 71 from the tank 7 via the mass flow controller 8 to the heating mechanism 9 in the sub-chamber 5. Then, the dropped reducing agent 71 is vaporized by the heating mechanism 9 to generate reducing gas, and the reducing atmosphere concentration in the sub-chamber 5 and the reducing chamber 4 is set to a predetermined value.

  Next, the shielding door 14a on the upstream side of the front chamber 11 is opened, the transport mechanism 3 is operated, the tray 2 on which the workpiece 1 is mounted is moved into the front chamber 11 and the shielding door 14a is closed. When the trays 2 on which the workpieces 1 are loaded are continuously inserted into a plurality of sheets, the upstream-side shielding door 14a is present because the waiting workpiece 1 that has been previously input exists in the front chamber 11. And the downstream shielding door 14b are simultaneously opened to simultaneously move the unprocessed workpiece 1 into the front chamber 11 and the standby workpiece 1 from the front chamber 11 into the reduction chamber 4. . In addition, since this can move the workpiece | work 1 similarly also in the reduction | restoration chamber 4 and the rear chamber 12, the description is abbreviate | omitted suitably.

  Next, the shielding door 14b on the upstream side of the reduction chamber 4 is opened, the workpiece 1 is sent into the reduction chamber 4, and the shielding door 14b of the reduction chamber 4 is closed. The front chamber 11 in which the reducing atmosphere in the reducing chamber 4 is diffused as the workpiece 1 moves is reduced while the workpiece 1 is reduced or the solder is joined in the reducing chamber 4. The exhaust gas is exhausted by the unit 16, the exhausted reducing gas is recovered by the reducing gas recovery mechanism unit 17, and the inert gas is supplied by the inert gas supply mechanism unit 15 to create an inert gas atmosphere. Since this operation is performed similarly in the rear chamber 12, the description thereof is omitted as appropriate.

  Next, the atmosphere in the reduction chamber 4 and the sub-chamber 5 is circulated through the circulation path 6 by rotating the fan 10. At this time, the reducing atmosphere having a constant concentration in the sub-chamber 5 is sent to the reducing chamber 4 through the forward path 6a. Further, the reducing atmosphere in the reducing chamber 4 whose concentration has been reduced by diffusion into the front chamber 11 is sent to the sub-chamber 5 through the return path 6b. Accordingly, at the same time, in order to replenish the amount of the reduced concentration, a certain amount of liquid reducing agent 71 is dropped from the tank 7 via the mass flow controller 8 and supplied to the heating mechanism 9 in the sub chamber 5.

  Then, the dropped reducing agent 71 is vaporized by the heating mechanism unit 9 to become a reducing gas, and the reducing atmosphere concentration in the sub-chamber 5 and the reducing chamber 4 is returned to a predetermined value. Here, since the capacity of the sub-chamber 5 is at least equal to or larger than the capacity of the reduction chamber 4, it is easy to set the concentration of the reducing gas to a predetermined value. Note that the fan 10 may be always rotated so that the atmosphere in the chambers 4 and 5 is constantly circulated. Alternatively, the fan 10 may be rotated only when the reducing atmosphere concentration in the chambers 4 and 5 is returned to a constant value. Further, since this operation is performed in the same manner even when the concentration is reduced by the diffusion of the reducing gas into the rear chamber 12, the description thereof is omitted as appropriate.

  Then, the reducing atmosphere concentration in the reducing chamber 4 is returned to a predetermined value, and at the same time, the heating mechanism 9 in the sub-chamber 5 is heated to start heating the workpiece 1. At this time, the heating temperature of the workpiece 1 is controlled so as to maintain the solder melting temperature or lower and the reduction of the oxide film. This is because when the temperature is raised to the solder melting temperature with the oxide film remaining partially without the reduction reaction proceeding, the solder wetted part and the part that does not get mixed together, resulting in uneven bonding quality. is there. Then, after the reduction of the oxide film on the surface of the solder is completed, the heating mechanism 9 is further heated, and the workpiece 1 is heated to the melting temperature of the solder to join the solder.

  Next, the shielding door 14 c on the downstream side of the reduction chamber is opened, the work 1 is sent to the rear chamber 12, and the shielding door 14 c on the downstream side of the reduction chamber 4 is closed. Next, the atmosphere in the rear chamber 12 is exhausted by the decompression mechanism 16, the exhausted reducing gas is recovered by the reducing gas recovery mechanism 17, and the inert gas is supplied by the inert gas supply mechanism 15. Use an inert gas atmosphere. When the atmosphere is replaced, the cooling mechanism 13 cools the work 1 by spraying an inert gas with a nozzle or the like. At this time, the inert gas used for cooling may have a low temperature in advance in order to increase the cooling capacity. Further, for example, another cooling method of pressing a water-cooled cooling plate against the work 1 may be combined. Next, the shielding door 14d on the downstream side of the rear chamber 12 is opened, the workpiece 1 is sent out of the rear chamber 12, and the shielding door 14d is closed. Next, the tray 2 and the work 1 are removed from the transport mechanism unit 3 and the processing is completed.

  According to the reflow apparatus of the first embodiment configured as described above, the work can be taken in and out without replacing the atmosphere in the reducing chamber with the inert gas, and the time required for replacing the atmosphere in the reducing chamber is reduced. In addition, the processing time required per work for one tray can be shortened. Moreover, since it is only necessary to supply a reducing gas having a reduced concentration due to diffusion of the reducing atmosphere to the front chamber or the rear chamber during workpiece transfer, the amount of reducing gas used can be reduced, and the reducing gas supply can be suppressed. It is possible to reduce the frequency of replenishment of the reducing agent to the tank of the mechanism and the work load for detoxifying the collected reducing agent. Therefore, energy saving is achieved, and the environmental load is reduced in the production process.

  Further, since the reducing gas is generated and circulated in the sub chamber, the reducing gas can be efficiently supplied to the reduction chamber.

  In addition, the heating mechanism in the sub-chamber performs both the temperature control of the reducing agent atmosphere and the gasification of the reducing agent, and thus does not require a dedicated device for the gasification of the reducing agent. Contributes to simplification of

  In addition, since the reducing gas supply mechanism is configured by the tank and the mass flow controller, the reducing gas can be supplied accurately.

  Further, since the volume of the sub chamber is formed to be equal to or larger than the volume of the reduction chamber, the concentration of the reducing gas in the sub chamber can be easily adjusted to a predetermined concentration of the reducing gas supplied to the reduction chamber.

  In addition, the heating mechanism can heat both the reduction of the oxide film on the surface of the solder and the bonding of the solder, and therefore can be manufactured efficiently.

  In addition, since the workpiece can be cooled by the cooling mechanism portion of the rear chamber, the manufacturing can be performed efficiently.

  In addition, since the atmosphere of the front chamber and the rear chamber can be replaced with the inert gas by the inert gas supply mechanism, the influence of the reducing gas on the outside can be reduced.

  In the first embodiment, an example in which a subchamber is provided and the reducing agent is vaporized in the subchamber is shown, but the present invention is not limited to this. For example, as shown in FIG. In addition, a reducing gas supply mechanism 70 that directly supplies the reducing gas to the circulation path 6 is provided. The reducing gas supply mechanism 70 includes a tank 20 in which reducing gas is sealed, and a valve 21 that connects the tank 20 and the circulation path 6 to adjust the amount of reducing gas. The heating mechanism unit 9 is disposed in the reduction chamber 4. Even when formed in this way, the same operation as in the first embodiment can be performed except for the supply of the reducing gas, and the same effect can be obtained. Since this is the same in the following embodiments, the description thereof will be omitted as appropriate.

  Further, in order to suppress a reduction in the reducing atmosphere concentration in the reducing chamber due to the movement of the workpiece, an inert gas or a reducing atmosphere was used for the upstream shielding door and the downstream shielding door. It is conceivable to provide a gas curtain, or to provide a mechanism for adjusting the pressures in the reduction chamber, the front chamber, and the rear chamber in the same manner. Since this is the same in the following embodiments, the description thereof will be omitted as appropriate.

Embodiment 2. FIG.
FIG. 3 is a diagram showing the configuration of the reflow apparatus according to Embodiment 2 of the present invention. In the first embodiment, the example in which the oxide film on the surface of the solder of the workpiece is reduced and the solder is joined in one chamber has been shown. However, in the second embodiment, A case where a heating chamber and a cooling chamber are provided separately will be described. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The rear chamber 12 is connected to the reduction chamber 4 and has a heating chamber 18 having a bonding heating mechanism 19 for heating the solder bonding process of the work 1 and a cooling chamber 18 connected to the heating chamber 18 for cooling the work 1. And a cooling chamber 22. A shielding door 14e is formed in the cooling chamber 22 on the downstream side.

  The decompression mechanism unit 16 is connected to the heating chamber 18 and the cooling chamber 22, and in particular, the inside of the heating chamber 18 can be decompressed, and the workpiece 1 can be held in a decompressed state in the heating chamber 18. Is. The inert gas supply mechanism 15 is connected to the heating chamber 18 and the cooling chamber 22.

  Next, the operation of the reflow apparatus of the second embodiment configured as described above will be described. In the second embodiment, the operation in the heating chamber 18 different from the first embodiment will be mainly described. First, through the same process as in the first embodiment, after the reduction of the oxide film on the solder surface of the workpiece 1 is completed in the reduction chamber 4, the shielding door 14c on the downstream side of the reduction chamber 4 is opened, and the workpiece is opened. 1 is sent to the heating chamber 18, and the shielding door 14c of the heating chamber 18 is closed.

  Next, the inside of the heating chamber 18 is evacuated to, for example, 10 Pa or less by the decompression mechanism unit 16. At the same time, heating is performed by the bonding heating mechanism 19 in the heating chamber 18 to heat the workpiece 1 to the melting temperature of the solder and to perform solder bonding. Therefore, by reducing the pressure in the heating chamber 18 when the solder is melted, voids in the solder can be removed and voids remaining in the solder after solder bonding can be reduced. Further, by controlling the heating during the decompression, it is possible to suppress defects such as the generation of solder balls caused by solder rapid boiling. Next, the shielding door 14d on the downstream side of the heating chamber 18 is opened, the workpiece 1 is sent to the cooling chamber 22, and the shielding door 14d of the heating chamber 18 is closed. Thereafter, similarly to the first embodiment, the workpiece 1 is cooled in the cooling chamber 22 by using the cooling mechanism unit 13.

  According to the reflow device of the second embodiment configured as described above, the heating chamber and the cooling chamber are separately provided as the rear chamber as well as the same effect as the first embodiment. Therefore, each process can be performed simply and with reduced time, and is particularly excellent when processing a plurality of workpieces. In addition, since the solder can be joined in a state where the pressure is reduced in the heating chamber, the quality of the solder joining can be improved.

  In the second embodiment, as in the first embodiment, the sub chamber is provided and the reducing gas is supplied in the sub chamber by vaporizing the reducing agent. However, the present invention is not limited to this. Instead, for example, as shown in FIG. 4, a reducing gas supply mechanism 70 that directly supplies the reducing gas to the circulation path 6 may be provided.

Embodiment 3 FIG.
FIG. 5 is a diagram showing the configuration of the reflow apparatus according to Embodiment 3 of the present invention. In the first embodiment, an example in which only cooling is performed as the rear chamber is shown. However, in the third embodiment, a case where solder bonding and cooling are performed in the rear chamber will be described. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted. In the rear chamber 12, a joining heating mechanism 19 that heats the workpiece 1 to the melting temperature of the solder and a cooling mechanism 13 that cools the workpiece 1 are provided. The decompression mechanism 16 is formed so that the interior of the rear chamber 12 can be decompressed, and can hold the workpiece 1 in a decompressed state in the rear chamber 12.

  Next, the operation of the reflow apparatus of the third embodiment configured as described above will be described. In the third embodiment, the operation in the rear chamber 12 different from that in the first embodiment will be mainly described. First, through the same process as in the first embodiment, after the reduction of the oxide film on the solder surface of the workpiece 1 is completed in the reduction chamber 4, the shielding door 14c on the downstream side of the reduction chamber 4 is opened, and the workpiece is opened. 1 is sent to the rear chamber 12 and the shielding door 14c of the rear chamber 12 is closed.

  Next, the inside of the rear chamber 12 is evacuated by the decompression mechanism 16 until the pressure becomes, for example, 10 Pa or less, as in the second embodiment. At the same time, heating is performed by the bonding heating mechanism 19 in the rear chamber 12 to heat the workpiece 1 to the melting temperature of the solder and perform solder bonding. Therefore, by reducing the pressure in the rear chamber 12 when the solder is melted, voids in the solder can be removed and voids remaining in the solder after solder bonding can be reduced. Further, by controlling the heating during the decompression, it is possible to suppress defects such as the generation of solder balls caused by solder rapid boiling. Next, as in the first embodiment, the workpiece 1 is cooled in the rear chamber 12 using the cooling mechanism unit 13.

  According to the reflow device of the third embodiment configured as described above, in addition to the same effects as those of the above-described embodiments, the solder bonding is performed in a state where the pressure is reduced in the rear chamber. Therefore, the quality of solder joint can be improved.

  In the third embodiment, an example in which a subchamber is provided and the reducing agent is vaporized in the subchamber is shown as in the above embodiments, but the present invention is not limited to this. Alternatively, for example, as shown in FIG. 6, a reducing gas supply mechanism 70 that directly supplies the reducing gas to the circulation path 6 may be provided.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

1 work, 2 trays, 3 transport mechanism, 4 reduction chamber, 5 sub-chamber,
6 Circulation path, 6a Outward path, 6b Return path, 7 Tank, 8 Mass flow controller,
9 heating mechanism, 10 fan, 11 front chamber, 12 rear chamber,
13 Cooling mechanism part, 14a Shielding door, 14b Shielding door, 14c Shielding door,
14d shielding door, 14e shielding door, 15 inert gas supply mechanism, 16 decompression mechanism,
17 reducing gas recovery mechanism, 18 heating chamber, 20 tanks, 21 valves,
22 cooling chamber, 19 bonding heating mechanism, 70 reducing gas supply mechanism,
71 Reducing agent.

Claims (10)

In the reflow apparatus for reducing the oxide film of the solder while heating the workpiece having solder,
A reduction chamber for performing a reduction treatment of the workpiece;
A front chamber connected to a front stage of the reduction chamber;
A rear chamber connected to a subsequent stage of the reduction chamber;
A reducing gas supply mechanism for supplying a reducing gas to the reducing chamber;
A heating mechanism for heating the reducing gas;
A reflow apparatus comprising a circulation path for taking out the reducing gas out of the reduction chamber and returning it back into the reduction chamber. A sub-chamber connected in the middle of the circulation path,
The reducing gas supply mechanism is connected to the sub-chamber,
The reflow apparatus according to claim 1, wherein the heating mechanism is disposed in the sub-chamber. The reducing gas supply mechanism section supplies a reducing agent to the heating mechanism section in the sub-chamber, and the reducing agent is heated and vaporized in the sub-chamber to generate the reducing gas and pass through the circulation path. The reflow apparatus according to claim 2, wherein the reflow apparatus is supplied to the reduction chamber. The reflow apparatus according to claim 3, wherein the reducing gas supply mechanism section includes a tank that encloses the reducing agent, and a mass flow controller that adjusts a supply amount of the reducing agent in the tank. The reflow apparatus according to any one of claims 2 to 4, wherein the volume of the sub chamber is formed to be equal to or larger than the volume of the reduction chamber. The reflow apparatus according to any one of claims 1 to 5, wherein the heating mechanism section is configured to heat the solder bonding process of the workpiece in the reduction chamber. The reflow apparatus according to any one of claims 1 to 6, wherein the rear chamber is provided with a cooling mechanism for cooling the workpiece. The rear chamber is connected to the reduction chamber, and has a heating chamber having a bonding heating mechanism for heating the solder bonding process of the workpiece,
A cooling chamber connected to the heating chamber for cooling the workpiece,
The reflow apparatus according to any one of claims 1 to 5, wherein the heating chamber includes a pressure reducing mechanism that depressurizes the inside of the heating chamber. The rear chamber is connected to the reduction chamber for heating the solder bonding process of the work, a cooling mechanism for cooling the work, and the rear chamber The reflow apparatus of any one of Claims 1-5 provided with the pressure-reduction mechanism part which decompresses. The reflow apparatus according to any one of claims 1 to 9, further comprising an inert gas supply mechanism that replaces an atmosphere of the front chamber and the rear chamber with an inert gas.

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