JPH06315766A - Method and device for soldering for oxidation inhibition - Google Patents

Abstract

PURPOSE:To prevent a bridge from being formed between electrodes by dissolved solder when IC tip parts are soldered on a substrate while being pull- soldered by robot work. CONSTITUTION:In the device to perform pull-soldering work on a member 33 to be soldered on the substrate 7, a soldering iron 28 is provided in a soldering iron case 27 so that the soldering iron 28 tip is projected from a soldering iron case 27 opening, a nozzle 20 to jet nonoxidative gas is provided in the soldering case 27 and the nonoxidative gas can be supplied from the soldering iron case 27 opening at the time of pull-soldering work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxidation preventing soldering method and apparatus for soldering IC chip parts and the like.

[0002]

2. Description of the Related Art Conventionally, when an IC chip component is soldered by a robot or the like, or soldered on a substrate by pulling solder, spot brazing, etc., flux-containing solder is used to prevent oxidation of the solder. The material was used or it was performed in a non-oxidizing atmosphere filled with nitrogen gas or the like.

[0003]

However, when soldering the lead wires around the chip component to the electrodes on the substrate, when the soldering work using the flux-containing solder material is performed, the melted solder will be caught between the electrodes. In addition to flowing down to form a bridge, the cost of the solder itself is high. In order to avoid this problem, it is necessary to limit the pitch of the lead wires on the outer periphery of the chip to a certain value or more, which causes a problem that the number of lead wires is insufficient for a chip having a large capacity. When performing a soldering operation in a non-oxidizing atmosphere by circulating a non-oxidizing gas throughout the work chamber, it takes a long time to reduce the oxygen concentration in the atmosphere.
There is a drawback that a large-scale gas generation and circulation facility is required, resulting in high cost and complicated operation and management.

[0004]

In order to solve the above problems, the method of the present invention is a method of heating a brazing portion 43 with a soldering iron 28 to melt the solder and perform soldering. The non-oxidizing gas is ejected from the outer periphery of the tip of the iron 28 toward the brazing part 43 to heat the brazing part while forming a non-oxidizing atmosphere around the brazing part. Further, the apparatus for carrying out the above method has an opening toward the brazing portion 43 in the vicinity of the tip position of the iron 28 for soldering by melting the solder by pressing the tip against the brazing portion 43. A nozzle 27 for discharging the non-oxidizing gas is provided, or the nozzle 27 is a cylindrical case that covers the outer periphery of the tip of the iron 28.

[0005]

When the heated iron 28 is pressed against the brazing portion 43 to melt the solder and perform soldering, a non-oxidizing gas is discharged from the nozzle 27 so that the brazing portion 43 is partially covered with the non-oxidizing gas. When an oxidizing atmosphere is formed and work is performed while preventing oxidation of the solder, bridges between the brazing parts 43 are also prevented,
It is not necessary to make the entire working space non-oxidizing. Further, by making the nozzle 27 a tubular case, the brazing part 43
The periphery is reliably formed in a non-oxidizing atmosphere with a small amount of gas regardless of the shape and structure of the brazed portion.

[0006]

FIG. 1 shows a soldering apparatus 1 (robot) according to an embodiment of the present invention, in which a movable table on a workbench 2 is guided by a linear guide 3 in the front-back direction to guide the front-back movement. 4, a plate 6 is mounted on the table 4, and a substrate 7 such as a printed circuit board is mounted on the upper surface of the plate 6. Further, a gate-shaped holder frame 8 is erected on the left and right ends of the workbench 2, and a slider 12 that is driven horizontally along a linear guide 11 is attached to a horizontal rod 9 of the holder frame 8.

The workbench 2 is provided in front of the slider 12.
On the other hand, an ascending / descending slider 14 that vertically elevates is attached, and a case 18 having a feeding drum 17 for the solder wire 16 and a feed roller (not shown) therein is installed on the ascending / descending slider 14. The case 18 is provided with a guide tube 21 that inserts and guides the thread solder 16 delivered from the delivery drum 17 inside, and the guide tube 21 extends downward and a tip end is attached to a holder 22.

A soldering head 23 is attached to the lower portion of the lifting slider 14, and a pipe 24 for holding a control wire for controlling the tip temperature and a tube 25 for supplying a non-oxidizing gas such as nitrogen are attached to the soldering head 23. Has been converged, piping 2
The tube 4 and the tube 25 are connected to the base end of a tubular iron case 27. An iron 28 connected to a heater is attached in the iron case 27 so that the tip of the iron protrudes from the opening at the tip of the case 27.
An annular space for gas flow is formed between 8 and the tip of the case opens toward the tip of the iron 28. Since the tip of the tube 25 for supplying non-oxidizing gas is connected to the iron case 27, the iron case 27 itself serves as a nozzle. The iron case 27 and the solder holder 22 are connected by a clip 29, and the tip end of the iron 28 and the tip end of the thread solder 16 are always close to each other at the same point.

Reference numeral 31 is a keyboard for performing horizontal movements of the table 4 and the slider 12, settings relating to vertical movements of the elevating slider 14, operation such as starting and stopping, and adjusting the tip temperature, and 30 is a keyboard 31. It is a controller with a built-in control device that is connected to.

In FIG. 3, I soldered on the substrate 7
The adhered member 33 such as a C chip is temporarily fixed and mounted on the substrate 7 with an adhesive together with a large number of lead wires 34 attached to the periphery thereof, and each lead wire 34 is attached to the surface of the substrate 7 by printing or the like. The brazed portion 43 is formed on the electrode 36 having a fine width. While the iron 28 and the solder wire 16 connected to the adherend member 33 by the clip 29 are sequentially moved in the horizontal direction in accordance with the pitch of the lead wires 34, each lead wire is pulled by pulling solder as shown in FIG. The wire 34 is soldered to the electrode 36. In this case, as described above, since the tube 25 connected to the gas supply device (not shown) for ejecting non-oxidizing gas such as nitrogen gas is connected to the base end of the iron case 27, the nitrogen gas is From the opening end of the case 27 toward the brazing portion 43, gas is intensively supplied to the soldering work portion, and the periphery is formed in a non-oxidizing atmosphere.

Since the soldering work is performed while the nitrogen gas is partially and intensively blown to the molten solder 41 in this manner, the surface of the molten solder 41 is activated, the surface tension is increased, and the electrode by the molten solder 41 is increased. No bridge between 36 is formed. In this case, the supply amount of nitrogen gas can be appropriately adjusted according to the amount and material of the solder material 16, the pitch of the lead wires 34, and the like. In addition to nitrogen, the non-oxidizing gas supplied may be hydrogen gas or a reducing or inert gas such as formic acid. If only these gases are supplied as an antioxidant measure, cleaning after soldering is not necessary. Become. The method and apparatus of the present invention can be used even when the pre-solder 42 is pre-deposited on the surface of the electrode as shown in FIG. 5, in which case the above-mentioned effects can be obtained without using the thread solder 16. Can play.

[0012]

According to the present invention configured as described above,
By partially and intensively supplying the non-oxidizing gas to the brazing portion, it is possible to perform good soldering in which a bridge does not occur between the electrodes even in high-density lead wire mounting. Further, since it is sufficient to supply the non-oxidizing gas only to the inside of the trowel case, the facility cost and the like can be significantly reduced as compared with the conventional case where the entire working chamber is made to have a nitrogen atmosphere.

[Brief description of drawings]

FIG. 1 is an overall front view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing the structure of the iron case.

FIG. 3 is a side sectional view showing a soldering member.

FIG. 4 is a side sectional view showing an embodiment of the present invention.

FIG. 5 is a side sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 7 substrate 27 trowel case 28 trowel 33 adherend 43 brazing part

Claims (3)

[Claims] 1. A soldering iron (28) for a brazing part (4)
In the method of heating 3) to melt the solder for soldering, the brazing part is formed by ejecting a non-oxidizing gas from the outer periphery of the tip of the iron (28) toward the brazing part (43). A method of soldering for preventing oxidation by heating while forming a non-oxidizing atmosphere in the periphery. 2. A soldering iron (2) for soldering by melting the solder by pressing the tip against the brazing part (43).
8) A soldering apparatus for oxidation prevention, which is provided with a nozzle (27) which is opened toward the brazing portion (43) and discharges a non-oxidizing gas near the tip position of 8). 3. A cylindrical shape in which a nozzle (27) covers the outer periphery of the tip of a trowel (28) and forms an annular space for the flow of non-oxidizing gas between the inner peripheral surface and the outer periphery of the trowel (28). The oxidation preventing soldering device according to claim 2, which is a case.