JPH0645745A - Reflow equipment - Google Patents

Abstract

(57) [Summary] [Purpose] A means for performing air reflow and chisso reflow with common temperature control in a reflow device that combines air reflow and chisso reflow. [Structure] A blower 21 for actively supplying air to the heating chamber 1 is provided. Further, a switching means 15 for switching the supply of nitrogen gas from the nitrogen gas supply portion 11 and the air supply from the air blower 21 is provided in the air supply conduit 14 that leads from the nitrogen gas supply portion 11 and the air blower 21 to the heating chamber 1. [Effect] At the time of the air flow, the blower 21 is driven to supply the same amount of air as the nitrogen gas at the time of the nitrogen reflow to the heating chamber 1, so that the same temperature profile can be obtained by the common temperature control.

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 reflow apparatus capable of selectively performing a chisso reflow and an air reflow.

[0002]

2. Description of the Related Art After mounting a chip on a substrate by a chip mounter or the like, the substrate is sent to a heating chamber of a reflow machine,
The electrodes of the chip are soldered to the electrodes of the substrate by heating and melting the solder and then cooling and solidifying the solder.

The reflow device supplies an air reflow device for heating the air in the heating chamber with a heater and a nitrogen gas as an inert gas to the heating chamber in order to prevent metal parts such as a circuit pattern of the substrate from being oxidized. , Is roughly divided into a nitrogen reflow device that heats nitrogen gas with a heater. Conventionally, the air reflow device and the chisso reflow device were separate devices, but in recent years, a reflow device has been proposed which can be used for both air reflow and chisso reflow by adding a nitrogen gas supply means to the air reflow device. Next, a conventional reflow apparatus will be described.

FIG. 3 is a side view showing the inside of the reflow apparatus. Inside the heating chamber 100, a conveyor 103 that conveys the substrate 10 on which the chips 9 are mounted from an inlet 101 to an outlet 102 is provided, and a heater 104 and a fan 105 are provided above the conveyor 103. . 1
Reference numeral 06 is a drive motor for the conveyor 103, and 107 is a drive motor for the fan 105. Also, entrance 101 and exit 1
02 is provided with a shutter 110 for preventing external air from flowing into the heating chamber 100. By driving a cylinder 111 to move the shutter 110 up and down, the inlet 101 and the outlet 102 are connected. Open and close. The interior of the heating chamber 100 is divided by a partition wall 112 into a preheating zone T1 on the inlet 101 side, a soaking zone T2 on the central portion, and a reflow zone T3 on the outlet 3 side.
At 2, T3, a nitrogen gas supply unit 113 such as a liquid nitrogen tank in which liquid nitrogen is stored and a nitrogen gas generator for separating nitrogen and oxygen in the air to generate nitrogen gas.
From, the nitrogen gas is supplied through the pipe 114.
Reference numeral 115 is a valve.

Next, the operation will be described. When performing the chisso reflow, the inlet 101 and the outlet 102 are connected to the shutter 110.
And the valve 115 is opened to close the heating chamber 100.
Hessian gas is supplied to fill the heating chamber 100 with nitrogen gas. Now, the substrate 10 on which the chips 9 are mounted is conveyed rightward by the conveyor 103. Meanwhile, the substrate 1
0 is the fan 1 that is the nitrogen gas heated by the heater 104.
The substrate 10 is heated by being sprayed with 05. Figure 4
The solid line A shows the temperature profile in the heating chamber 100 during the nitrogen reflow. As shown, in general,
In the preheating zone T1, the temperature of the substrate 10 is from room temperature to 150.
It is heated to about ℃, then 1 in the soaking zone T2
It is heated to about 70 ° C. and then to 220 ° C. or higher in the reflow zone T3. The melting temperature of the solder 14 is about 183 ° C., and the solder 14 is melted by rapidly heating the substrate 10 to about 223 ° C.

Next, when air reflow is performed, the inlet 10
1 and the shutter 110 at the outlet 102 are opened, and the valve 115 is closed to stop the supply of nitrogen gas to the heating chamber 100. Then, the heating chamber 100 is filled with air, and in that state, soldering is performed while the substrate 10 is conveyed by the conveyor 103 as in the case of the nitrogen reflow.

A chain line B in FIG. 4 indicates a heating chamber 1 during air reflow.
00 shows a temperature profile of 00. As illustrated, the temperature profile B of air reflow is higher than the temperature profile of nitrogen reflow. The reason is as follows. In the Chisso reflow, the heating chamber 100
A considerable amount of nitrogen gas is constantly or almost always supplied to the inside, but since the nitrogen gas is at a low temperature (normal temperature), heat is taken to heat the nitrogen gas to the above temperature. On the other hand, in the air reflow, the outside air only slightly flows in from the inlet 101 and the outlet 102. That is, the amount of air flowing into the heating chamber 1 during air reflow is considerably smaller than the amount of nitrogen gas supplied to the heating chamber 100 during nitrogen reflow, and as a result, the temperature profile B of air reflow is higher than the temperature profile of nitrogen reflow. That is why.

[0008]

In the reflow apparatus, when the actual temperature profile deviates from the ideal temperature profile, insufficient solder heating or excessive heating causes deterioration of solder quality. Therefore, it is necessary to strictly control the temperature control means such as the heater in order to bring it closer to the ideal temperature profile, but in the conventional reflow apparatus described above, the temperature profile changes between the chisso reflow and the air reflow, so that the temperature control is performed separately. Therefore, there is a problem that it is extremely difficult to manage the operation of the equipment because it has to be close to the ideal temperature profile.This is one of the main reasons why reflow equipment that can use both air reflow and chisso reflow is not popular. Was becoming.

Therefore, an object of the present invention is to provide a reflow apparatus which can easily match the temperature profiles of air reflow and nitrogen reflow.

[0010]

To this end, the present invention provides a blower for positively supplying air to the heating chamber.
Further, a switching means for switching between the supply of the nitrogen gas from the nitrogen gas supply portion and the air supply from the air blower is provided in the air supply pipe line leading from the nitrogen gas supply portion and the air blower to the heating chamber.

[0011]

According to the above construction, during the air reflow, the blower is driven to positively supply the heating chamber with an amount of air substantially equal to the amount of the nitrogen gas supplied during the nitrogen reflow.
The temperatures and specific heats of air and nitrogen gas are almost the same, and therefore, if similar temperature control is performed by air reflow and nitrogen reflow, the same temperature profile will be obtained.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a side view showing the inside of the reflow apparatus. Inside the heating chamber 1, there is provided a conveyer 4 that conveys the substrate 10 on which the chips 9 are mounted from the inlet 2 to the outlet 3. Above the conveyer 4, a heater 5 and a fan 6 are provided. . 8 is a motor for driving the conveyor 4,
Reference numeral 7 is a drive motor for the fan 6. Further, the inlet 2 and the outlet 3 are provided with a shutter 18 for preventing outside air from flowing into the heating chamber 1, and a cylinder 19 is provided.
Is driven to move the shutter 18 up and down to open and close the inlet 2 and the outlet 3.

The interior of the heating chamber 1 is divided by a partition wall 16 into a preheating zone T1 on the inlet 2 side, a soaking zone T2 at the center and a reflow zone T3 on the outlet 3 side. Reference numeral 11 denotes a nitrogen gas supply unit such as a liquid nitrogen gas cylinder or a nitrogen gas generator that separates nitrogen and oxygen in the air to generate nitrogen gas, and each zone T1, T2, T3 of the heating chamber 1 through the air supply conduit 14, Nitrogen gas is supplied to a cooling chamber 20 provided at the rear of the heating chamber 1. This air supply line 14
A flow rate adjusting valve 12 and a flow meter 13 are provided in the. Two
Reference numeral 1 denotes a blower, which is connected to a switching valve 15 provided in the air supply conduit 14, and a flow rate adjusting valve 22 and a flow meter 23 are also provided in the middle thereof. By operating the switching valve 15, the nitrogen gas supply by the nitrogen gas supply unit 11 to the heating chamber 1 and the air supply by the blower 21 are selectively switched.

Next, the operation will be described. When performing the nitrogen reflow, the inlet 2 and the outlet 3 are closed by the shutter 18, the valve 15 is opened to supply the nitrogen gas to the heating chamber 1, and the heating chamber 1 is filled with the nitrogen gas. The substrate 10 having the chips 9 mounted thereon is conveyed rightward by the conveyor 4. Meanwhile, the nitrogen gas heated by the heater 5 is blown onto the substrate 10 by the fan 6 to heat the substrate 10. Next, when air reflow is performed, the shutters 18 at the inlet 2 and the outlet 3 are opened, the valve 15 is switched, the supply of nitrogen gas to the heating chamber 1 is stopped, the blower 21 is driven, and the heating chamber 1 is supplied. While supplying air
The board 10 is conveyed by the conveyor 4 to perform soldering.

In this case, the flow meter 2 is arranged so that the amount of nitrogen gas supplied and the amount of air supplied during nitrogen reflow are the same.
The flow rate is measured at 3, and the flow rate is adjusted by the flow rate adjusting valve 22.
In this way, if the amount of nitrogen gas supplied during nitrogen reflow and the amount of air supplied during air reflow are the same, the temperature and specific heat of nitrogen gas and air are almost the same, so the temperature profile during air reflow is It becomes the same as the temperature profile at the time. Therefore, in air reflow and nitrogen reflow, the same temperature profile can be obtained by controlling the temperature management means such as the heater 5 and the fan 6 in exactly the same manner.

FIG. 2 shows another embodiment of the present invention.
The nitrogen gas supply unit 11 and the blower 21 have independent air supply pipe lines 14A and 14B and valves 15A and 15B, respectively. Therefore, by switching the valves 15A and 15B, nitrogen gas or air is supplied to the heating chamber 1. As described above, various piping structures can be considered.

[0018]

As described above, according to the present invention, during the air reflow, the blower is driven to positively supply the heating chamber with the same amount of air as the amount of the nitrogen gas supplied during the nitrogen reflow. It is possible to obtain the same temperature profile as the above, and therefore, the chisso reflow and the air reflow can operate the device under the common temperature control, and the temperature control means such as the heater and the fan can be easily controlled.

[Brief description of drawings]

FIG. 1 is a side view of a reflow apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of a switching mechanism according to another embodiment of the present invention.

FIG. 3 is a side view of a conventional reflow device.

FIG. 4 is a temperature profile diagram of a conventional reflow apparatus.

[Explanation of symbols]

 1 Heating Chamber 2 Inlet 3 Outlet 4 Conveyor 5 Heater (Temperature Management Means) 6 Fan (Temperature Management Means) 11 Chisso Gas Supply Section 14 Air Supply Pipeline 15 Valve (Switching Means) 21 Blower

Claims (1)

[Claims] 1. A heating chamber, a conveyer for conveying a substrate from an inlet to an outlet of the heating chamber, and a heater arranged in the heating chamber for heating a substrate conveyed by the conveyer.
There is a fan that blows hot air to the substrate, a nitrogen gas supply unit that supplies nitrogen gas to this heating chamber, a blower that supplies air to this heating chamber, and an air supply conduit that leads from this nitrogen gas supply unit and the air blower to the heating chamber. A reflow device comprising a switching means for switching the supply of nitrogen gas from the nitrogen gas supply section and the supply of air from the blower.