JPH05111754A - Nitrogen re-flow device - Google Patents

Abstract

PURPOSE:To control the temperature rising of the uniform heating zone and lower the temperature of the cooling zone, by cooling the nitrogen gas and again returning it to each original zone on the way of the by-pass route which introduces the high temperature nitrogen gas of the uniform heating zone and the cooling zone. CONSTITUTION:A high temperature nitrogen gas N2 in an uniform heating zone and a cooling zone is once introduced to a by-pass routes 16a, 16b by driving a suction fan 17, the nitrogen gas N2 which flows in the bypass route 16a, 16b is cooled and returns again to each zones 7, 9 by blowing the air generated by driving the fan 18 against the bypass route 16a, 16b on the way of this bypass route. Therefore, the rising of temperature of the uniform heating zone 7 is controlled, the uniform heating zone 7 is kept in the almost uniform temperature, and the temperature of the neighbor of outlet part 13 is reduced, so the ideal temperature profile T can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chisso reflow apparatus, and more particularly to a means for cooling a soaking zone and a cooling zone of a heating chamber to realize an ideal temperature profile of the reflow apparatus.

[0002]

2. Description of the Related Art When mounting electronic components on a substrate, cream solder is applied to the electrode portion of a circuit pattern such as a copper foil formed on the substrate, the electronic components are bonded onto the cream solder, and then this substrate is mounted. Is sent to the reflow device and the heat treatment of the cream solder is performed. Conventionally, such heat treatment of solder has been performed by an air reflow device having an air heating means.

A conventional air reflow apparatus will be described with reference to FIG. The substrate 5 is conveyed by the conveyor 4 into the heating chamber 3 in which the heater 1 and the fan 2 are arranged, and the heater 1 heats the cream solder for bonding the electronic component P to the substrate 5. The interior of the heating chamber 3 is divided by a partition wall into a preheating zone 6, a soaking zone 7, and a high-temperature melting zone 8 for melting the cream solder, and a low-temperature cooling zone 9 is arranged downstream of the heating chamber 3. The temperature of the soaking zone 7 is maintained substantially constant by supplying air at room temperature to the soaking zone 7 from the outside, and the high temperature air in the preheating zone 6 and the cooling zone 9 is discharged to the dashed arrow. As shown, by introducing room temperature air from the inlet portion 12 and the outlet portion 13, the temperature near the inlet portion 12 and the outlet portion 13 is lowered, and an ideal temperature profile as shown by the solid line T in the figure is realized.

However, in such an air reflow apparatus, since the air supplied to the heating chamber 1 contains oxygen, the circuit pattern made of copper foil or the like and the metal portion such as cream solder are heated. There is a problem that it is easy to oxidize, and when it oxidizes, the wetting property of the solder deteriorates, and the electronic component P cannot be easily adhered to the substrate 5 well.

As a remedy for this problem, there has been proposed a nitrogen reflow device for performing heat treatment in a nitrogen gas atmosphere in which there is no fear of oxidation of the circuit pattern or cream solder.

A conventional chisso reflow apparatus will be described with reference to FIG. The same parts as those shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 14 denotes a nitrogen gas supply section, and the nitrogen gas N2 supplied from the nitrogen gas supply section 14 is constantly supplied into each zone 6 to 9 of the heating chamber 3.

[0007]

However, since the conventional nitrogen reflow apparatus performs the heat treatment in the nitrogen gas atmosphere, the air containing oxygen is introduced into the heating chamber 1 like the air reflow apparatus shown in FIG. Therefore, the temperature profile T cannot be realized, and the temperature profile as shown by the broken line T ′, that is, the temperature profile in the soaking zone 7 gradually increases, and the temperature profile in the cooling zone 9 does not sufficiently decrease. Was becoming. In particular, since the temperature drop in the cooling zone 9 is insufficient, the substrate 5 is discharged from the heating chamber 1 without being sufficiently cooled, and as a result, reacts with oxygen in the air to cause a metal portion such as a circuit pattern of the substrate 5. However, there was a problem that it was easily oxidized.

Therefore, an object of the present invention is to provide a chisso reflow device which can realize an ideal temperature profile.

[0009]

According to the present invention, there is provided a heating chamber and a cooling zone which are provided with a heater and a fan and which are divided into a preheating zone, a soaking zone and a melting zone from an inlet portion toward an outlet portion. , A conveyor that conveys the substrate from the inlet to the outlet of the heating chamber, and in a Chisso reflow device having a Chisso gas supply unit that supplies Chisso gas to the heating chamber, in the soaking zone and or cooling zone,
A bypass passage is provided for discharging the high-temperature nitrogen gas in the heating chamber and returning it to the heating chamber again, and a cooling means for the nitrogen gas is provided in the middle of the bypass passage.

[0010]

In the above structure, the high temperature nitrogen gas in the soaking zone and / or the cooling zone is led out by the bypass passage, and in the middle of the bypass passage, the nitrogen gas is cooled by the cooling means and returned to each zone again, so that the uniform temperature is maintained. An ideal temperature profile can be realized by preventing the temperature in the heat zone from rising and reducing the temperature near the outlet as much as possible.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. The same components as those shown in FIGS. 2 and 3 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a side view of the chisso reflow apparatus. Reference numeral 15 denotes a shower unit provided in the cooling zone 9, which sprays new nitrogen gas N2 supplied from the nitrogen gas supply unit 14 onto the substrate 5 on the conveyor 4 to effectively cool the substrate 5. 16a and 16b are bypass passages, which are provided in the soaking zone 7 and the cooling zone 9. In this embodiment, the bypass paths 16a, 1
The suction portions a and b of 6b are provided below both zones 6 and 9 where the temperature of the nitrogen gas N2 is low in order to improve the thermal efficiency.

Reference numeral 17 is a fan for sucking nitrogen gas N2, which is provided in the middle of each bypass 16a, 16b, and 18 is a fan as a cooling means. By driving the suction fan 17, the soaking zone 7 and the cooling zone 9
The high temperature nitrogen gas N2 in the inside is once passed through the bypass passages 16a, 16
b, and the air generated by the drive of the fan 18 is blown from the outside to the bypass passages 16a, 16b in the middle of the bypass passages 16a, 16b to blow the bypass passages 1a, 16b.
The nitrogen gas N2 flowing in 6a and 16b is cooled and returned to the zones 7 and 9 again. As a result, the temperature rise in the soaking zone 7 is suppressed, the soaking zone 7 maintains a substantially constant temperature, and the temperature in the vicinity of the outlet 13 is lowered, so that an ideal temperature profile T can be realized. Moreover, according to this means, the nitrogen gas N2 in the heating chamber 3 is bypassed to the bypass passages 16a and 16b.
Since it is possible to realize the ideal temperature profile T while circulating the air, there is no need to supply new cooling nitrogen gas N2 to the heating chamber 3 in order to realize this ideal temperature profile T, and the consumption of expensive nitrogen gas N2 The amount can be reduced and an ideal temperature profile can be realized with low running cost.

The present invention is not limited to the above embodiment. For example, in the bypass passage 16a, if the return port side of the nitrogen gas N2 is connected to the fan 2, the fan 2 for suction can be used without using the suction fan 17. By utilizing the wind pressure of, the nitrogen gas N2 can be distributed in the road.

[0015]

As described above, according to the present invention, in the soaking zone and / or the cooling zone of the heating chamber, a bypass passage is provided, in which the hot nitrogen gas in the heating chamber is led out and returned to the heating chamber again. By configuring a chisso reflow device by providing a cooling means for the nitrogen gas on the way, it is possible to suppress the temperature rise in the soaking zone and lower the temperature in the cooling zone to realize an ideal temperature profile. Since it is not necessary to newly supply the nitrogen gas into the heating chamber in order to realize the ideal temperature profile, the consumption amount of expensive nitrogen gas can be reduced and the running cost can be suppressed.

[Brief description of drawings]

FIG. 1 is a side view of a chisso reflow device according to the present invention.

FIG. 2 is a side view of an air reflow device according to a conventional means.

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

[Explanation of symbols]

 1 Heater 2 Fan 3 Heating Chamber 5 Substrate 6 Preheating Zone 7 Soaking Zone 8 Melting Zone 9 Cooling Zone 12 Inlet 13 Outlet 14 Chisso Gas Supply 16 Bypass 18 Cooling Means N2 Chisso Gas

Claims (1)

[Claims] 1. A heating chamber and a cooling zone, which are provided with a heater and a fan, and are divided into a preheating zone, a soaking zone, and a melting zone from an inlet portion to an outlet portion, and an inlet portion of the heating chamber. In a Chisso reflow apparatus having a conveyor for conveying a substrate to the outlet and a Chisso gas supply unit for supplying Nisso gas to the heating chamber, the soaking zone and / or the cooling zone, the high temperature Chisso gas in the heating chamber is led out again. A chisso reflow device comprising a bypass passage for returning to the heating chamber, and a cooling means for the nitrogen gas provided in the middle of the bypass passage.