JP2751515B2 - Reflow soldering apparatus and method of heating reflow soldering apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention heats a printed circuit board (hereinafter abbreviated as a substrate) on which an electronic component is mounted on cream solder, thereby soldering the electronic component to the substrate. And a heating method.

[Related Art] When bonding a chip resistor or the like to a substrate, a semiconductor chip is generally reflow-soldered using cream solder.

FIG. 5 shows an overall view of this type of conventional reflow soldering apparatus, and FIG. 7 shows an example of a temperature profile measured on a substrate of the apparatus. As shown in FIG. 5 and FIG. 6, the substrate 1 is horizontally conveyed by an endless chain in the direction of the arrow, and reaches a certain level in a first preheating section provided with far-infrared panel heaters 3 and 4 and a hot air nozzle 5. It is heated to raise the temperature, and the hot air blowing nozzle 6
In the second preheating section provided with a heater, the heater is heated so as to be maintained at a certain temperature, and the far-infrared panel heater 7
And 8, in a flow section provided with a hot-air blowing nozzle 9, after the solder is heated so as to be melted, the solder is fixed by a cooling device 10 and then carried out.

In the above, the details of the transport direction of the substrate will be described below.

As shown in FIGS. 6 (a) and 6 (b), the endless chain 2 has guide rails 11a arranged in parallel and at the same height.
And 11b, the sprockets 12 and 1 have linear sliding properties.
Rotation is performed by prokets 15a and 15b attached to the rotation shafts of 3 and 14 and the drive source 16. As shown in FIG. 6 (c), a pin 17 for holding the end of the substrate 1 protrudes from one side of the chain, and the movement of the plurality of pins accompanying the movement of the chain causes the pin 17 to move. The substrate 1 placed in contact with the upper portion is transported.

Next, FIG. 7 shows a temperature profile of a certain point on the surface of the substrate 1 during the transfer. The horizontal axis of the graph indicates time, and the vertical axis indicates temperature. As shown in FIG. 7, while the substrate 1 is transported at a certain speed in the first preheating section having the far infrared panel heaters 3 and 4 and the hot air blowing nozzle 5 in FIG. between T _1, it is heated to a temperature theta _1. And after the substrate 1 passes through a first preheating section, the second preheating unit provided with the said heat-air blow out nozzle 6, while being conveyed at a certain speed, as shown in FIG. 7, the transport time (T ₂ - T ₁₎
Between, is heated and held at a temperature theta _1. As shown in FIG. 7, while the substrate 1 having passed through the second pre-coating section is conveyed at a certain speed through the far-infrared ray panel heaters 7 and 8 and the reflow section provided with the hot-air blowing nozzle 9, between transport time (T ₃ -T _2), it is heated to a maximum temperature theta _2. After that, the substrate 1 is cooled by the cooling device 10, and the temperature decreases.

[Problems to be Solved by the Invention] However, in the above-described reflow soldering apparatus of the related art, as shown in FIGS.
But because they are transported at a constant speed in the endless chain 2, the pre-heating time T ₂ in the first preheating section and a second pre-heat section, a flow time in the reflow section (T ₃ -T ₂₎
Is proportional to the ratio of the furnace length L ₁ in the first preheating section and the furnace length L ₂ in the reflow section, respectively. Therefore, for example, when trying to arbitrarily change the ratio between the preheating time and the reflow time in the temperature profile,
It is necessary to change the furnace length of the preheat section and the reflow section, which has a problem that it is very difficult on an actual apparatus. When the mounting board is transported and the temperature profile is measured, the maximum temperature θ shown in FIG.
_{Numeral 2} is one of the indices for preventing damage to the components on the substrate. When setting the maximum temperature θ ₂ , the far infrared panel heaters 7 and 8 shown in FIG.
In addition, there is a problem that the set temperature of the hot air blowing nozzle 9 must be operated and determined through trial and error.

The present invention solves the above-mentioned problems of the prior art,
By performing heat treatment while transporting the substrate in the vertical direction while keeping the substrate horizontal, the time ratio between the preheating part and the reflow part can be changed, and the flexible temperature profile can be set arbitrarily and the substrate It is an object of the present invention to provide a reflow soldering apparatus in which the maximum temperature on the surface can be arbitrarily set by adjusting a stop time in a reflow section, and a heating method thereof.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following constitution.

"(1) An apparatus for transporting a board on which electronic components are mounted on cream solder and reflowing the board, wherein a plurality of boards with horizontal board surfaces are maintained at a constant interval and vertically intermittently fed. A pre-heating section for conveying and pre-heating in the direction,
A horizontal transport unit for moving the preheated substrate horizontally from a vertical transport unit of the preheating unit to a reflow unit in a horizontal direction with respect to a base of the apparatus, and a reflow unit for soldering the substrate. Reflow soldering equipment.

(2) In order to cool the substrate after it has been carried out of the reflow unit, a means for cooling the horizontal transfer unit is provided, or a plurality of substrates having a horizontal substrate surface are intermittently fed at a constant interval. 2. The reflow soldering apparatus according to claim 1, further comprising: means for cooling while conveying in a vertical direction.

(3) An apparatus for transporting a substrate on which electronic components are mounted on cream solder and reflowing the substrate, wherein a plurality of substrates having horizontal substrate surfaces are maintained at a constant interval and intermittently fed in a vertical direction. A pre-heating unit for transferring and pre-heating the pre-heated substrate, a horizontal conveying unit for moving the pre-heated substrate horizontally from a vertical conveying unit of the pre-heating unit to a reflow unit with respect to a base of the apparatus, and soldering the substrate. A soldering process using an apparatus including a reflow unit for performing a heat treatment, wherein the stop time of the substrate in the reflow unit is reduced by a plurality of substrate receiving units disposed in the vertical transport unit of the preheating unit. Reflow soldering wherein the setting can be changed within the stop time of one stage, and the ratio between the preheating time in the preheating section and the reflow time in the reflow section can be arbitrarily changed. Heating method of the attachment device. [Operation] According to the configuration of the apparatus of the present invention, in the preheating portion of the reflow soldering apparatus, a mechanism for vertically transporting a plurality of substrates having horizontal substrate surfaces at intermittent feed intervals at a certain interval. In addition, between the preheating unit and the reflow unit, a horizontal transfer mechanism for moving the uppermost substrate of the vertical transfer unit to the reflow unit is provided, so that the stop time (reflow time) in the reflow unit is shorter than that of the preheat unit. Since any setting can be made within the stop time of one stage of the substrate receiving unit in the plurality of substrate receiving units disposed in the vertical transport unit, the ratio of the preheating time in the preheating unit to the reflow time in the reflow unit is determined. It can be changed flexibly.

According to the preferred configuration of the device of the present invention described above,
In order to cool the board after the reflow section has been carried out, a means for cooling the horizontal transport section is provided, or a plurality of boards with the board surface horizontal are kept at a constant interval, and intermittently fed vertically. Since the cooling means is provided while being transported, the substrate can be cooled efficiently.

Furthermore, according to the heating method of the present invention, in the reflow unit, the substrate stop time is set to the substrate receiving unit 1 of the plurality of substrate receiving units disposed in the vertical transport unit of the preheating unit.
Allows setting to be arbitrarily changed within the stop time at the step, so that when determining the temperature profile on the mounting board, the maximum temperature on the mounting board surface, which is an index to prevent damage to components, is It can be set by adjusting the stop time in the section. This makes the condition setting operation easier than the setting by adjusting the temperature of the heating source in the related art.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an overall view of the reflow soldering apparatus, FIG. 2 is a side view of the pre-heater vertical transfer section as viewed from FIG. 1 as viewed from an arrow A, and FIG. 3 is a flow as viewed from FIG. FIG. 4 is a side view of the general horizontal mounting part, and FIG. 4 shows an example of a temperature profile measured in the apparatus.

As shown in FIG. 1 and FIG. 2, the substrate 1 carried in from the direction of the arrow moves upward while being supported by the substrate receiving portions 22a and 22b attached to the endless chains 19a and 19b and supporting the substrate ends. Go. The driving of the chains 19a and 19b is performed by a driving source 18 on a shaft 25 to which the bevel teeth 23a and 23b are attached.
, The bevel gears 24a and 24b integrated with the pulley are rotated at an angle of 90 degrees, and the belt 21
provided via a and 21b. The substrate 1 is preheated by the hot air devices 26a and 26b when moving upward, and is preheated by the hot air device 31 when positioned at the uppermost position.

Further, as shown in FIG. 3, the substrate 1 located at the uppermost part of the preheating portion is provided with a pusher sliding along the guide rail 27.
By 28, both ends are held by the board transfer rails 32a and 32b, transferred to the center of the reflow section equipped with the hot air devices 34a and 34b, stopped, and heated and reflowed. Note that the pusher 28 is fixed to a chain 30 that is hung between the sprockets 29a and 29b, and the drive is given from a drive source 38 to which the sprocket 29a is attached.

After the substrate 1 is heated and reflowed, it is cooled in a cooling unit of a vertical transport system having a mechanism similar to that of the preheating unit.
Cooling. Then, when the substrate 1 comes to the lowermost part of the vertical transport section, it is carried out by a pusher 37 attached to the tip of the air cylinder 36.

Next, FIG. 4 shows a temperature profile of a certain point on the surface of the substrate during the transfer. The horizontal axis of the graph indicates time, and the vertical axis indicates temperature. The substrate is pre-heat portion provided with the hot air device 26a and 26b in Figure 1, while being intermittently fed vertically, as shown in FIG. 4, is heated to a temperature theta ₁ between the conveyance time T _1. Then, the substrate is heated and held at the temperature θ ₁ during the stop time (T ₂ −T ₁ ) at the uppermost portion of the preheating section. The substrate transported from the uppermost part of the preheating part to the flow part and stopped is the hot air devices 34a and 34b.
As shown in FIG. 4, the stop time (T ₃ −T ₂ )
Between it is heated to a maximum temperature theta _2. At this time, the stop time (T ₃ −T ₂ ) in the reflow unit can be changed within the stop time in one stage of the substrate receiving unit disposed in the vertical transfer unit of the preheating unit. For example, if the stop time is (T ₃ ′
−T ₂ ), the maximum temperature is as low as θ ₂ ′.

According to one embodiment of the present invention described above, in the preheating section of the flow soldering apparatus, a mechanism is provided for transporting a plurality of substrates having horizontal substrate surfaces in a vertical direction by intermittent feed while maintaining a certain interval. Also, by providing a mechanism for stopping the substrate in the flow section, the time ratio between the preheating section and the reflow section can be made variable, and a flexible temperature profile can be obtained. Further, since the maximum temperature on the substrate surface can be set by adjusting the stop time in the reflow section, it is more convenient than setting by adjusting the temperature of the heating source.

[Effects of the Invention] According to the present invention described above, in the preheating section of the reflow soldering apparatus, there is provided a mechanism for transporting a plurality of substrates having horizontal substrate surfaces in a vertical direction by intermittent feeding at a certain interval. In addition, between the preheating unit and the reflow unit, a horizontal transfer mechanism for moving the uppermost substrate of the vertical transfer unit to the reflow unit is provided, so that the stop time (reflow time) in the reflow unit is reduced by the vertical length of the preheat unit. Substrate receiving portion 1 in a plurality of substrate receiving portions disposed in the transport portion
Because it can be set arbitrarily within the stop time at the stage,
The effect of being able to flexibly change the ratio between the preheating time in the preheating section and the reflow time in the reflow section can be achieved.

According to the preferred configuration of the apparatus of the present invention described above, in order to cool the substrate after being carried out of the reflow unit, the horizontal transfer unit is provided with cooling means, or
Keeping a certain interval between multiple boards with the board surface horizontal,
Since the cooling means is provided while transporting the substrate in the vertical direction by intermittent feeding, the effect of efficiently cooling the substrate can be achieved.

Further, according to the heating method of the present invention, in the reflow unit, the stop time of the substrate is adjusted by the substrate receiving unit 1 of the plurality of substrate receiving units disposed in the vertical transfer unit of the preheating unit.
The setting can be changed arbitrarily within the stop time at the step, so that when determining the temperature profile on the mounting board, the maximum temperature on the mounting board surface, which is an index to prevent damage to components, is It can be set by adjusting the stop time in the section. This can achieve the effect that the condition setting operation is easier than the setting by adjusting the temperature of the heating source in the related art.

[Brief description of the drawings]

FIG. 1 is a front view of a flow soldering apparatus according to an embodiment of the present invention, FIG. 2 is a side view of a pre-heating section vertical transport section viewed from an arrow A in FIG. 1, and FIG. FIG. 4 is a side view of a reflow section horizontal transfer section viewed from a view A. FIG. 4 is a view showing a temperature profile of a point on a substrate surface according to one embodiment of the present invention. FIG. 5 is a front view of a conventional reflow soldering apparatus. 6, FIG. 6 is a front view and a side view of the transport unit in FIG. 5, and FIG. 7 is a diagram showing a temperature profile at a certain point on the substrate surface in the prior art. 1 ... board, 2, 19, 20, 30 ... chain, 3, 4, 7, 8 ... far infrared panel heater, 5, 6, 9 ... hot air blowing nozzle, 10, 35
…… Cooling device, 11,27,32 …… Rail, 12,13,14,15,29…
… Sprocket, 16,18,33 …… Drive source, 17 …… Pin, 21
... belt, 22 ... board receiving part, 23, 24 ... bevel gear, 2
5… Shaft, 26,31,34… Hot air device, 28,37… Pusher, 36… Air cylinder

Claims (3)

(57) [Claims] 1. An apparatus for transporting a substrate on which electronic components are mounted on cream solder and reflowing the substrate, wherein a plurality of substrates having a horizontal substrate surface are intermittently fed at a constant interval. A pre-heating unit that vertically conveys and pre-heats, a horizontal conveyance unit that moves the pre-heated substrate horizontally from a vertical conveyance unit of the pre-heating unit to a reflow unit with respect to a base of the apparatus, and the substrate And a reflow section for performing soldering. 2. The apparatus according to claim 1, further comprising means for cooling the horizontal transfer section for cooling the substrate after the substrate has been carried out of the reflow section, and / or keeping a plurality of substrates having a horizontal substrate surface at a constant interval. 2. The reflow soldering apparatus according to claim 1, further comprising means for cooling while being conveyed in a vertical direction by intermittent feeding. 3. An apparatus for transporting a substrate on which electronic components are mounted on cream solder and reflowing the substrate, wherein a plurality of substrates having a horizontal substrate surface are intermittently fed at a constant interval. A pre-heating unit that transports vertically and pre-heats, a horizontal transport unit that moves the pre-heated substrate horizontally from a vertical transport unit of the pre-heat unit to a reflow unit with respect to a base of the apparatus, A method of performing a heat treatment of solder using an apparatus including a reflow unit for performing soldering, wherein the stop time of the substrate in the reflow unit is reduced by a plurality of substrate receiving units disposed in the vertical conveyance unit of the preheating unit. A reflow process wherein the setting can be changed within the stop time of one stage of the substrate receiving portion, and the ratio between the preheating time in the preheating portion and the reflow time in the reflow portion can be arbitrarily changed. Heating method of soldering equipment.