JPS62183960A - Reducing atmosphere furnace for soldering - Google Patents

Abstract

PURPOSE:To easily control a heating temperature, and quickly execute heating and cooling, by executing the heating and cooling of a product by a direct heating floor and a direct cooling floor. CONSTITUTION:A semiconductor product 100 is placed on a guide rail 14a of an entry of a direct heating floor 10. Subsequently, an abutting surface 43 of a pusher 40 is pressed against the product 100 and pushed out along the rail 14a, and it is transferred slowly into a reducing box 30. In the reducing box 30 which has been filled with hydrogen gas, the product 100 moves on a stainless steel plate 13 of the direct heating floor 10, therefore, it is heated directly and a temperature rises. While it is moving on the direct heating floor 10, soldering of the product 100 is executed, and during that time, the soldered part is reduced by the hydrogen gas, and passive parts are connected quickly and also, exactly. Also, when the product 100 passes through an outlet and extruded to the outside of the reducing box 30 by the pusher 40, the product 100 is moved onto a direct cooling floor 20 along a guide rail 24a, and cooled quickly therein.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reducing atmosphere furnace for soldering, which is used for mounting chips, connecting components, and the like.

[Conventional technology]

Conventional hybrid IC% semiconductor products.

It is manufactured by first fixing the semiconductor to a printed circuit board using thermosetting resin, then performing wire bonding, and then soldering passive components such as resistors and capacitors.

When soldering passive components, the metal part (copper part) of the curtain plate is heated to high temperatures, so cream solder containing flux is usually used to prevent oxidation of that part.

However, one of the problems with such a manufacturing method is that after soldering, cleaning and drying operations must be performed to remove flux, which reduces production efficiency. In addition, some of the passive parts attached to the product have sliding parts, such as variable resistors, and if flux gets caught in those parts during cleaning, they may no longer function normally, or painted parts may become damaged due to cleaning. Some items may disappear or are not suitable for cleaning.

Therefore, recently, instead of flux-cored solder, a reducing atmosphere furnace is used to solder passive components, and a soldering bonding method that does not require cleaning afterward has been implemented.In other words, wire bonding is completed. rear,
In this method, a board with passive components mounted at the required locations is placed on a conveyor belt, placed in a reducing atmosphere furnace, and is indirectly heated by the high temperature reducing atmosphere filled inside, thereby performing soldering. be.

[Problem that the invention seeks to solve]

However, when attempting to solder using such a reducing atmosphere furnace, hydrogen gas is normally used as the reducing atmosphere, and heating during solder bonding is indirect heating by the atmosphere. Because of this, it is difficult to control the heating temperature, and therefore a large furnace of about 8 to 10 m is usually required. Additionally, in addition to requiring equipment to indirectly heat the atmosphere to a high temperature, after soldering is completed, the product is cooled by the atmosphere in the furnace, so cooling equipment is also required to indirectly cool the atmosphere. This led to an increase in costs. Furthermore, the larger the furnace capacity, the longer the working time required for indirect heating and indirect cooling, and the higher the running cost, which leads to a decrease in productivity.

The present invention was devised in view of the above-mentioned problems, and is an attempt to solve the above-mentioned problems by fundamentally improving the above-mentioned reducing atmosphere furnace.

[Means for solving problems]

FIG. 1 is a schematic diagram showing the basic configuration of a reducing atmosphere furnace for soldering according to the present invention. Here, the furnace of the present invention has a direct heating bed +1'l, a direct cooling bed (21) and a reduction box (3) provided above the direct heating bed 11 that is continuous with this bed.
and a pusher (4) installed on the directly heated bed (11 people side).

The direct heating bed (1) is a product such as an electric heater (ioo
), and the heating temperature can be controlled, and the product (100) can be placed and moved on it in its original state.

In addition, the direct cooling bed (2) is used to cool the product (10
0) that can be directly cooled and the cooling temperature can be controlled, and has the same original configuration as the heating bed +11 on which the product (100) can be placed and moved.

Further, the reduction box (3) is installed so as to directly cover the heating bed (1), and is a device that fills the inside with a reducing atmosphere and prevents oxidation during heating of the product (100).

The pusher (4) connects the direct heating bed Il+ and the direct cooling bed (2) as a loading and moving path for the product (100).
is provided, so instead of the conventional conveyor belt, the product (100) is directly pushed out from the inlet side of the heating bed through the reduction box (3) and directly towards the outlet side of the cooling bed (2).

[For production]

In the furnace having the above configuration, after wire bonding is completed, the semiconductor product (100) loaded with passive components and solder for bonding them is moved to the pusher (4).
) directly from the inlet side of the heating bed +1) to the reduction box (3
) and heated directly by a heated bed (1) in a reducing atmosphere. At this time% the direct heating bed (
1] performs heating while controlling the heating temperature. After the product (100) is soldered in this way, the pusher (4) further heats the product (100).
) is pushed directly to the cooling bed (2+ side) and its cooling is performed.

〔Example〕

FIG. 2 is a side view showing an embodiment of the reducing atmosphere furnace of the present invention. Among them, αO is a direct heating bed, (a) is a direct cooling bed, ■ is a reduction box, and (40) is a pusher.

As shown in FIG. 3(A), the above-mentioned direct heating bed GO is equipped with a plurality of electric heaters (6 to 6) installed in the width direction of the stainless steel frame QllP3.
) Consisting of a perforated stainless steel plate 4 shown in Figure 1 (b) arranged so as to be in contact with the top surface, and a guide rail (14a) for product movement laid over the stainless steel plate opening.
When the product (100) is transferred onto (14b), the product (100) is directly heated by the electric heater CLz. In this way, since the direct heating bed an directly heats the product (100) using the electric heater aa, the heating temperature can be quickly adjusted to the optimum temperature (approximately 350° 0).

Further, the direct cooling bed (2) is provided continuously to the direct heating bed αO, and its structure is as shown in FIG. 4(a).
Inside the aluminum container C21), there is provided a cooling water channel 4 which meanders in an S-shape and is open at the top, and a product movement guide rail (2+a) ( The perforated stainless steel plate shown in FIG. Cooling water cooled by a pump (a) to a radiator is circulated in the cooling water channel (4), and when the soldered product (100) is transferred onto the stainless steel plate, the cooling water is circulated through the cooling water channel (4). Allow to cool. In this way, the direct cooling bed (4
) cools the product (10(1)) directly by circulating the cooling water while being cooled by the radiator (radiator), allowing rapid cooling.

Further, the reduction box (2) is a sealed box-shaped box installed so as to cover the directly heated unopened O, and a hydrogen gas inlet (31) is provided in the upper part of the box, and a hydrogen gas source (31) is provided therein. Since the introduction pipe (32) is connected to the box (not shown), the inside of the box ω is filled with a reducing atmosphere due to the injection of hydrogen gas. In addition, the side wall of the reduction box ω is provided with an entrance (aa) (34) for conveying the product (100) along the length of the direct heating bed (1 (J) and the direct cooling bed (a)). N and gas flow through it like an air curtain to create a gas shield and prevent atmospheric air from entering the inside.

The pusher (40) is directly provided outside the inlet side of the heating bed αO, and the pusher (40) is directly provided outside the inlet side of the heating bed αO, and is attached to the end of the rod (42).
3), and is a device that directly pushes the product (1oo) from the inlet side of the heating bed αO through the reduction box Tanai to the outlet side of the cooling bed (1).

The reducing atmosphere furnace of this embodiment having the above configuration is used in the following manner. First, after wire bonding is completed, the semiconductor product (IOO) mounted with passive components and solder etc. to bond them is placed directly on the guide rail (x4a) (t4b) on the inlet side of the heating bed αO, and then the pusher (40 ) of the product (roo
) and push it out along the guide rails (14a) and (14b), and slowly transport it into the reduction box ω from the entrance (34). Then, inside the reduction box field filled with hydrogen gas, the product (100) moves over the stainless steel plate mouth of the direct heating bed Q(l), so it is directly heated by the air heater (6) of the direct heating bed αO. , immediately 350
Raise the temperature to around 0°. In this way, the product (100) is soldered while moving directly on the heated bed aa,
During this time, the soldered portion is reduced by hydrogen gas, so that the passive components can be quickly and reliably connected. Furthermore, the product (1) is pushed by the pusher (40).
00) is pushed out of the reduction box ω through the outlet (35), the product (100) passes through the guide rail (24a).
) (s+ab) directly onto the cooling bed, where it is rapidly cooled.

〔Effect of the invention〕

As explained above, according to the reducing atmosphere furnace of the present invention,
Instead of indirect heating and cooling using a reducing atmosphere, the product is heated and cooled by direct heating and cooling using a direct heating bed and direct cooling bed, making it easier to control the heating temperature and reducing heat and cooling. It has the excellent effect that the process can be carried out quickly and the entire device can be made compact to about 1 m. In addition, as mentioned above, instead of indirect heating and cooling using the atmosphere, heating and cooling are performed using a direct heating bed and a direct cooling bed, which eliminates the need for atmosphere heating and cooling equipment, resulting in lower equipment costs.
It also has the advantage of reducing the work time required for heating and cooling and reducing running costs, thereby improving productivity.

The reducing atmosphere furnace of the present invention can also be used to prevent bubbles from forming on the bonding surface when soldering items that require a large bonding area, such as large-capacity diodes and thyristors. can.

[Brief explanation of drawings]

The mx diagram is a schematic diagram showing the basic configuration of the present invention, Figure 2 is a side view showing an embodiment of the present invention, and Figures 3 (a) and (b) are explanations showing the configuration of the direct heating bed in this embodiment. Figure, Figure 4 (
a) and (b) are explanatory diagrams similarly showing the configuration of a direct cooling bed. In the figure, +11αO is a direct heating bed, +2) (1) is a direct cooling bed % +31 CIQ is a reduction box, (4) (40
) indicates a pusher, and (1oo) indicates a semiconductor product. Patent Applicant: R.I. Ichigo Kogyo Co., Ltd. Inventor: Toshio Furuya Representative Patent Attorney: Sho Yoshihara Santsutsu ¥1 Procedural Amendment Showa B/Year/Month: 1g Day

Claims (1)

[Scope of Claims] A direct heating bed, a direct cooling bed provided in succession to the direct heating bed, a reduction box installed above the direct heating bed and filled with a reducing atmosphere, and a direct heating bed in which the product is heated. A reducing atmosphere furnace for soldering, characterized in that it has a pusher that pushes the cooling bed directly from the inlet side through the reduction box toward the outlet side.