JP3114278B2 - Chisso reflow device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

A conventional air reflow device will be described with reference to FIG. The substrate 5 is transported by the conveyor 4 into the heating chamber 3 in which the heater 1 and the fan 2 are provided, and the heater 1 performs a heating process of cream solder for bonding the electronic component P to the substrate 5. The interior of the heating chamber 3 is partitioned by a partition wall into a preheating zone 6, a soaking zone 7, and a high-temperature melting zone 8 for melting cream solder, and a low-temperature cooling zone 9 is provided downstream of the heating chamber 3. The room temperature air is supplied from the outside to the soaking zone 7 to keep the temperature in the soaking zone 7 substantially constant, and the high-temperature air in the preheating zone 6 and the cooling zone 9 is discharged, and the dashed arrow As shown in the drawing, by introducing normal-temperature air from the inlet 12 and the outlet 13, the temperature near the inlet 12 and the outlet 13 is lowered, and an ideal temperature profile as shown by the solid line T in FIG.

However, in such an air reflow apparatus, since oxygen is contained in the air supplied into the heating chamber 1, a circuit pattern made of copper foil or the like or a metal part such as cream solder is heated. There is a problem in that the electronic component P is easily oxidized, and if oxidized, the wetting property of the solder is reduced, and the electronic component P cannot be satisfactorily bonded to the substrate 5.

As a remedy, there has been proposed a nitrogen reflow apparatus for performing a heat treatment in a nitrogen gas atmosphere in which there is no possibility of oxidizing a circuit pattern or cream solder.

Referring to FIG. 3, a conventional nitrogen reflow apparatus will be described. The same components as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. Reference numeral 14 denotes a nitrogen gas supply unit. The nitrogen gas N2 supplied from the nitrogen gas supply unit 14 is constantly supplied to each of the zones 6 to 9 of the heating chamber 3.

[0007]

However, in the conventional nitrogen reflow apparatus, since heat treatment is performed in a nitrogen gas atmosphere, air containing oxygen is introduced into the heating chamber 1 as in an 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 gradually increases even in the soaking zone 7 and the temperature profile in which the temperature does not sufficiently decrease in the cooling zone 9. Had become. In particular, since the temperature in the cooling zone 9 is not sufficiently lowered, the substrate 5 is discharged from the heating chamber 1 without being sufficiently cooled, and reacts with oxygen in the air to form a metal part 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 nitrogen reflow apparatus capable of realizing an ideal temperature profile.

[0009]

According to the present invention, there is provided a heating chamber and a cooling zone in which a heater and a fan are provided, and are divided into a preheating zone, a soaking zone, and a melting zone from an inlet to an outlet. a conveyor for conveying the substrate from the inlet portion of the heating chamber to the outlet portion, the nitrogen reflow apparatus having a Chissogasu supply unit for supplying Chissogasu in the heating chamber, to derive the hot Chissogasu above Symbol pressurized heat chamber Rutotomoni a bypass passage for returning again heating chamber, a cooling means Chissogasu in the middle of the bypass passage, the cooling
The nitrogen gas cooled by the
Alternatively, it is returned to the cooling zone .

[0010]

In the above construction, the high-temperature nitrogen gas in the heating chamber is led out by the bypass passage, and in the middle of the bypass passage, the nitrogen gas is cooled by the cooling means so as to form a soaking zone.
By returning the over emissions and or cooling zones, it can be realized ideal temperature profile.

[0011]

Next, an embodiment of the present invention will be described with reference to the drawings. The same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and description thereof is omitted.

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

Reference numeral 17 denotes a fan for sucking nitrogen gas N2, which is provided in the middle of each of the bypass passages 16a and 16b, and 18 denotes a fan as cooling means. By driving the suction fan 17, the high-temperature nitrogen gas N 2 in the heating chamber 3 is once led to the bypass passages 16 a and 16 b, and air generated by driving the fan 18 in the middle of the bypass passages 16 a and 16 b is supplied from the outside. Bypass path 16a,
The nitrogen gas N2 flowing in the bypass passages 16a and 16b is sprayed onto the cooling passage 16b, and then cooled again.
Return to zone 9. Thus, the temperature rise in the soaking zone 7 is suppressed, the soaking zone 7 is maintained at a substantially constant temperature, and the temperature near the outlet 13 is reduced, so that an ideal temperature profile T can be realized. Moreover, according to this means, the heating chamber 3
An ideal temperature profile T can be realized while circulating the nitrogen gas N2 in the inside of the bypass passages 16a and 16b, so that a new cooling nitrogen gas N2 is supplied to the heating chamber 3 in order to realize the ideal temperature profile T. There is no need to reduce the consumption of expensive nitrogen gas N2, and an ideal temperature profile can be realized at low running cost.

The present invention is not limited to the above-described embodiment. For example, if the return path of the nitrogen gas N2 is connected to the fan 2 on the bypass passage 16a, this fan 2 can be used without using the suction fan 17. The flow of nitrogen gas N2 in the road can be carried out using the wind pressure.

[0015]

The present invention described above, according to the present invention is Rutotomoni a bypass passage for returning again heating chamber to derive the hot Chissogasu indoor pressurized heat is provided with a cooling means Chissogasu in the middle of the bypass passage the in, reduce the temperature rise of the soaking zone, also lowers the temperature of the cooling zone, Ru can achieve ideal temperature profile. Moreover, since it is not necessary to newly supply nitrogen gas to the heating chamber in order to realize an ideal temperature profile, consumption of expensive nitrogen gas can be reduced and running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a nitrogen 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 chisso reflow device according to a conventional means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater 2 Fan 3 Heating chamber 5 Substrate 6 Preheating zone 7 Uniform heating zone 8 Melting zone 9 Cooling zone 12 Inlet 13 Outlet 14 Nitrogen gas supply 16 Bypass passage 18 Cooling means N2 Nitrogen gas

Continuation of front page (56) References JP-A-64-83395 (JP, A) JP-A-3-216272 (JP, A) JP-A-64-71571 (JP, A) JP-A-3-216273 (JP) JP-A-4-274868 (JP, A) JP-A-3-8564 (JP, A) JP-A-4-46666 (JP, A) JP-A-2-87557 (JP, U) Field surveyed (Int.Cl. ⁷ , DB name) B23K 1/012 B23K 31/02 B23K 101: 42

Claims (1)

(57) [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 to an outlet. a conveyor for conveying the substrate to the outlet portion, the nitrogen reflow apparatus having a Chissogasu supply unit for supplying Chissogasu in the heating chamber, a bypass passage for returning again heating chamber to derive the above SL pressurized heat indoor hot Chissogasu <br/> provided Rutotomoni, a cooling means Chissogasu in the middle of the bypass passage, which is cooled by the cooling means Chissogasu
Return to the soaking zone and / or the cooling zone.
A chisso reflow device characterized by the following.