JPH05299829A - Reflow equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a reflow device capable of avoiding excessive reheating of a solder part or a chip. An upper hot air route A for blowing hot air onto the upper surface of the substrate S is provided above the heating chamber 1, and a lower hot air route B for blowing hot air onto the lower surface of the substrate S is provided below the heating chamber 1. Moreover, route switching means 9 and 12 for selectively blowing hot air from the upper hot air route A and the lower hot air route B to the upper surface and the lower surface of the substrate S are provided. [Effect] In the second reflow, the solder part H1 on the lower side of the substrate S is reheated and melted, and the chip P1 bonded to the substrate S is dropped or thermally destroyed by the solder part H1. It can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow apparatus, and more particularly, to a solder portion or a chip provided on a substrate by selectively blowing hot air onto the upper surface and the lower surface of a double-sided mounting substrate that is transported in a heating chamber. Is to avoid excessive reheating.

[0002]

2. Description of the Related Art Today, in order to achieve high-density mounting of substrates,
Double-sided mounting, in which chips are mounted on the upper and lower surfaces of a substrate, is performed. In this double-sided mounting, solder parts such as cream solder and solder precoat are formed on the electrodes of the circuit pattern formed on one surface of the board, the chip is mounted on this solder part, and then this board is sent to the reflow device. Then, the solder portion on the other surface of this substrate is heat-treated to perform the first reflow, then the substrate is turned upside down, and the solder portion is formed on the electrode portion of the circuit pattern formed on the other surface of this substrate, Similarly, after mounting a chip on this solder portion, this substrate is sent to the reflow device again, and the second reflow is performed in which the solder portion on the other surface of this substrate is heat-treated. Next, a conventional reflow device used for the heat treatment of the solder portion will be described with reference to the drawings.

FIG. 5 is a cross-sectional view of a reflow apparatus according to the conventional means. 100 is a heating chamber, 101 is a lower portion of the heating chamber 100, and a substrate S is an inlet portion 102 of the heating chamber 100.
From the outlet to the outlet 103, 104 is a heater housed in the upper and lower parts of the heating chamber 100, 105
Is a fan.

After the solder portion H1 is formed on the upper surface 106 of the substrate S and the chip P1 is mounted on the solder portion H1, the substrate S is sent to the reflow apparatus. As shown by the solid line in the figure, the substrate S entering the heating chamber 100 through the inlet 102.
Is conveyed in the heating chamber 100 by the conveyor 101,
During this conveyance, the heat of the heater 104 is blown to the upper surface 106 and the lower surface 107 of the substrate S by the fan 105, and the first reflow process for heating the solder portion H1 is performed.

Next, the substrate S is turned upside down, and the substrate S
After the solder portion H2 is formed on the electrode portion of the circuit pattern formed on the lower surface 107 of the substrate and the chip P2 is mounted on the solder portion H2, the substrate S is sent to the reflow device again as shown by the chain line in the figure. , While being conveyed by the conveyor 10,
A second reflow process is performed in which the solder portion H2 formed on the electrode on the lower surface 107 is heat-treated.

[0006]

As described above, the double-sided mounting board S is turned upside down after heating the solder portion H1 on the upper surface 106 for the first time, and then the solder portion H2 on the lower surface 107 is heated. A second reflow to process must be done. Therefore, the solder portion H1 which has been turned downward due to the front-back reversal is reheated during the second reflow. Therefore, the solder portion H1 is melted, and the chip P1 becomes the substrate S.
There was a problem of falling from. In addition, there is a problem that the risk of thermal destruction of the chip P1 is increased by the heat during the second reflow.

Therefore, an object of the present invention is to provide a reflow apparatus capable of avoiding excessive reheating of a solder portion or a chip of a double-sided mounting substrate in the second reflow.

[0008]

To this end, according to the present invention, an upper hot air route for blowing hot air onto the upper surface of the substrate is provided in the upper portion of the heating chamber, and hot air is blown onto the lower surface of the substrate to the lower portion of the heating chamber. A lower hot air route is provided, and a route switching means for selectively blowing hot air from the upper hot air route and the lower hot air route to the upper surface and the lower surface of the substrate is provided.

[0009]

According to the above structure, the route switching means is operated to selectively blow hot air from the upper hot air route and the lower hot air route to the upper surface and the lower surface of the substrate, thereby making it possible to remove solder or It is possible to avoid excessive reheating of the chips.

[0010]

(Embodiment 1) Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a perspective view of the reflow apparatus according to the first embodiment of the present invention, and 1 is a heating chamber. The heating chamber 1 contains a conveyor 4 that conveys the substrate S from the inlet 2 to the outlet 3 of the heating chamber 1. P1 is a chip adhered to the substrate S by the solder portion H1. FIG. 1 is a cross-sectional view of the heating chamber 1. Inside the heating chamber 1, a conveyor 7 is provided in the middle, and a duct 7 forming an upper hot air route A for blowing hot air onto the upper surface of the substrate S is provided above the conveyor 4. A duct 10 forming a lower hot air route B for blowing hot air onto the lower surface of the substrate S is provided below the duct 10. The duct 7 and the duct 10 are vertically symmetrical and have the same shape.

An opening 7a and an opening 7b are formed on both sides of the lower portion of the duct 7 of the upper hot air route A, and a heater 8 and a fan 9 are provided in the center of the upper portion. The opening 7a and the opening 7b are formed laterally in the lower portion of the duct 7 so as to face each other. When the fan 9 is driven, the heat of the heater 8 is heated by the opening 7a as shown by the arrow in the figure.
Substrate S blown out from and conveyed by conveyor 4.
Is horizontally blown from the lateral direction onto the upper surface of the sheet and is sucked into the duct 7 again through the opening 7b to circulate.

On both sides of the upper portion of the duct 10 of the lower hot air route B, an opening 10a and an opening 10b are formed laterally so as to face each other, and a heater 11 and a fan 12 are provided in the center of the lower portion. It is provided. Fan 12
Is driven, the heat of the heater 11 is blown out from the opening 10a as shown by the arrow in the drawing, and is blown horizontally from the lateral direction onto the lower surface of the substrate S conveyed by the conveyor 4,
The duct 10 is sucked again from the opening 10b and circulates. When the heater 11 and the fan 12 on one side are stopped and the heater 8 and the fan 9 on the other side are driven, hot air circulates only in the upper hot air route A, and only the upper space T1 surrounded by the substrate S and the duct 7 becomes hot. , Only the upper surface of the substrate S is heated. On the contrary, one heater 8
And the fan 9 are stopped and the other heater 11 and the fan 12 are driven, the hot air circulates only in the lower hot air route B, and the lower space T2 surrounded by the substrate S and the duct 10.
Is heated to a high temperature, and only the lower surface of the substrate S is heated. That is, the upper hot air route A and the lower hot air route B are switched by selectively switching the drive of the fan 8 or 9. The fans 9 and 12 are forward / reverse fans, and their rotation directions can be arbitrarily switched. This reflow apparatus has the above-mentioned configuration, and its operation will be described below.

After the solder portion H1 is formed on the one surface 5 of the substrate S and the chip P1 is placed thereon, the first reflow process of heating the solder portion H1 formed on the one surface 5 is performed.
As shown by the solid line in FIG. 1, the substrate S is transported by the conveyor 4 in the heating chamber 1 with the one surface 5 on which the chips P are mounted as the upper surface. During this conveyance, the heat of the heaters 8 and 11 is driven by the fans 9 and 12 as shown by the arrow in FIG.
It is sprayed horizontally from the lateral direction on the upper surface and the lower surface of the substrate S from a and 10a.

The hot air from the upper hot air route A heats the solder portion H1 on the upper surface 5 of the substrate S, and the hot air from the lower hot air route B heats the lower surface 6 of the substrate S to accelerate the melting of the solder portion H1. To do. The substrate S for which the heating process has been completed is sent from the outlet section 3 to the outside of the heating chamber 1. Of course, in this case, the lower surface of the substrate S may not be positively heated by the lower hot air route B, and the driving of the heater 11 and the fan 12 below may be stopped. Further, by changing the rotation direction of the fans 9 and 12, the reflow may be performed while appropriately changing the circulation direction of the hot air, and by doing so, it is possible to eliminate the local temperature unevenness of the substrate S.

Next, the substrate S is turned upside down to form solder portions H2 on the electrodes on the other surface 6, and the chips P are attached to the solder portions H2.
After mounting 2, the second reflow is performed. This 2
Similarly to the first reflow, the second reflow is also performed while the substrate S is being conveyed by the conveyor 4 as shown by the chain line in FIG. 1. At this time, the reflowed solder portion H1 on the lower surface side is also used.
Heater 1 of the lower hot air route B so that it is not heated again
1 and fan 12 stop driving, and heater 8 and fan 9
Is driven to circulate the hot air only in the upper hot air route A, and the solder portion H2 on the other surface 6 is heat-treated.

Since the circulation of the hot air in the lower hot air route B is stopped in this way, the hot air cannot be blown to the lower surface. Therefore, the solder portion H1 that has undergone the first reflow is not reheated by the heat during the second reflow, and it is possible to prevent the solder portion H1 from melting and dropping the chip P1. The risk of thermal destruction of P1 can be reduced.

(Second Embodiment) FIG. 3 shows a second embodiment according to the present invention.
13 is a cross-sectional view of the reflow apparatus of FIG. 1, 13 is a duct of the upper hot air route A, and a pair of openings 13a are formed laterally on both lower sides of the duct 13 so as to face each other, and an upper central portion thereof A downward opening 13b is formed in the. A pair of heaters 14 and fans 15 are provided on both sides of the upper portion of the duct 13, and the heat of the heaters 14 is blown out from the left and right openings 13a as shown by the arrows in FIG. The hot air is blown horizontally from both lateral directions onto the upper surface of the substrate S, and then rises and is sucked into the opening 13b.

Reference numeral 16 is a duct for the lower hot air route B,
A pair of openings 16a are formed laterally on both sides of the upper portion of the duct 16 so as to face each other, and an upward opening 16b is formed at the center of the lower portion.
A pair of heaters 18 and fans 19 are provided on both sides of the lower part of the duct 16, and the heat of each heater 18 is blown out from the left and right openings 16a as shown by the arrows in FIG. , Hot air is blown horizontally from both lateral directions onto the lower surface of the substrate S, and then descends to open the opening 16
sucked into b. The duct 13 and the duct 16 are also vertically symmetrical and have the same shape.

Reference numeral 25 is an upper shutter provided as a route switching means in each opening 13a, and 26 is a lower shutter similarly provided as a route switching means in each opening 16a. These shutters 25, 26
Is opened and closed by a driving means such as a cylinder (not shown) to selectively blow hot air from the upper hot air route A and the lower hot air route B to the upper surface and the lower surface of the substrate S. In addition,
The upper hot air route A normally circulates the hot air constantly during reflow, and therefore the upper shutter 25 does not necessarily have to be provided, and the upper shutter 25 and the upper hot air route A can be opened and closed by opening and closing the lower shutter 26. Hot air may be selectively blown from the side hot air route B to the upper surface and the lower surface of the substrate S. This device is constructed as described above, and the operation will be described below.

After forming the solder portion H1 on the one surface 5 of the substrate S and mounting the chip P1 thereon, the first reflow process for heating the solder portion H1 on the one surface 5 is performed. At this time,
The shutters 25 and 26 are opened and the upper hot air route A and the lower hot air route B are opened as shown in FIG. Fan 1
When the heaters 5 and 19 are driven, the heat of the heaters 14 and 18 is blown out from the openings 13a and 16a, and the one surface 5 of the substrate S
Hot air is blown from both lateral directions to the other surface 6 to heat the solder portion H1, and the ducts 13 and 1 from the openings 13b and 16b.
It is sucked in 6. At this time, hot air is blown horizontally from both lateral directions of the chip P to the solder portion H1 through the openings 13a formed on both sides of the duct 13, so that the first embodiment
As compared with the above case, the temperature unevenness of the substrate S can be prevented and the entire surface of the substrate S can be heated more uniformly.

Next, the substrate S is turned upside down, solder portions H2 are formed on the electrodes on the other surface 6 and the chip P2 is mounted,
The second reflow is performed while the substrate S is being conveyed by the conveyor 4. At this time, the reflowed solder part H on the lower surface side
The lower shutter 26 of the lower hot air route B is closed so as not to reheat 1 and the heater 18 and the fan 19 are driven to circulate the hot air only in the upper hot air route A, and the other surface 6
The solder part H2 is heat-treated.

(Third Embodiment) FIG. 4 shows a third embodiment according to the present invention.
2 is a cross-sectional view of the reflow device, and 20 is a duct that also serves as a duct for the upper hot air route A and a duct for the lower hot air route B. An opening 20a and an opening 20b are formed on both sides of the upper portion of the duct 20, and an opening 20c and an opening 20d are formed on both sides of the central portion of the duct 20. Both openings 20
An upper shutter 27 is provided at a and 20b, and a lower shutter 28 is provided at both openings 20c and 20d.

During the first reflow, as shown in FIG. 4, the shutters 27 and 28 are opened and the upper hot air route A and the lower hot air route B are opened. When the fan 23 is driven, the heat of the heater 22 is blown out from each of the openings 20a and 20c, and hot air is blown from one lateral direction to one surface 5 and the other surface 6 of the substrate S to heat the solder portion H1. Part 20
It is sucked into the duct 20 from b and 20d.

Next, the substrate S is turned upside down, solder portions H2 are formed on the electrodes on the other surface 6 and the chip P2 is mounted,
The second reflow is performed while the substrate S is being conveyed by the conveyor 4. At this time, each lower shutter 28 is closed, the lower hot air route B is closed, and the solder portion H2 is heat-treated by the upper hot air route A.

[0025]

As described above, in the present invention, an upper hot air route for blowing hot air onto the upper surface of the substrate is provided in the upper part of the heating chamber, and a lower side for blowing hot air onto the lower surface of the substrate is provided in the lower part of the heating chamber. Since the hot air route is provided and the route switching means for selectively blowing hot air from the upper hot air route and the lower hot air route to the upper surface and the lower surface of the board is provided, the solder portion of the double-sided mounting board is reflowed for the second time. In this case, it is possible to prevent the chip bonded to the substrate from being dropped or thermally destroyed by being excessively reheated and melted by the solder portion.

[Brief description of drawings]

FIG. 1 is a sectional view of a reflow device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a reflow device according to a first embodiment of the present invention.

FIG. 3 is a sectional view of a reflow device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a reflow device according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a reflow device according to a conventional means.

[Explanation of symbols]

 1 heating chamber 4 conveyor 8 heater 9 fan (route switching means) 11 heater 12 fan (route switching means) 14 heater 15 fan 18 heater 19 fan 22 heater 23 fan 25 route switching means 26 route switching means 27 route Switching means 28 Route switching means A Upper hot air route B Lower hot air route S Substrate

Claims (1)

[Claims] 1. A reflow apparatus comprising a heating chamber in which a heater and a fan are accommodated, and a conveyer accommodated in the heating chamber to convey a substrate, and hot air is blown onto the upper surface of the substrate above the heating chamber. In addition to providing an upper hot air route, a lower hot air route for blowing hot air to the lower surface of the substrate is provided in the lower part of the heating chamber, and the upper hot air route and the lower hot air route are selectively applied to the upper surface and the lower surface of the substrate. A reflow apparatus comprising a route switching means for blowing hot air.