JPH0679765B2 - Vapor reflow soldering equipment - Google Patents

Description

The present invention relates to a vapor reflow type soldering device,
Particularly, the present invention relates to a vapor reflow soldering device suitable for soldering a high-density mounting printed wiring board using semiconductor chip components such as so-called flat pack ICs, resistors, capacitors, etc., in which electrode terminals are taken out in a plane in four directions. It is a thing.

[Conventional technology]

In recent years, high-density mounting of electronic components on printed wiring boards is progressing more and more, but the soldering work for bonding electronic components such as semiconductor chip components to the printed wiring board is the final process of the line, so the quality of soldering is not good. Since it affects the performance of parts, the soldering technology is considered to be the most important technology in the line.

Recently, since it is necessary to improve the uniformity of temperature distribution in the furnace where soldering work is performed and to avoid harmful overheating of electronic components, steam with a large specific gravity to air is used as the heat medium and its condensation latent heat is used. Vapor reflow soldering equipment that heats an object to be processed has been drawing attention.

In this device, for example, as described in JP-A-60-106502, an electronic component is mounted on a solder pattern of a printed wiring board, and the printed wiring board has a large thermal specific gravity as described above. It is a device for soldering by passing it through saturated vapor of medium.

First, a conventional typical vapor reflow soldering apparatus will be described with reference to FIGS. 7 and 8.

FIG. 7 is a configuration diagram of a conventional vapor reflow soldering device, and FIG. 8 is a sectional view taken along the line DD in FIG.

In FIGS. 7 and 8, reference numeral 1'denotes a reflow chamber. The reflow chamber 1'is a steam generation tank 4'which heats a heat medium 12 by a heater 7 to generate saturated steam 13, and steams an object 16 to be treated. Carrying-in / carrying path 5 carried into the generating tank 4, carrying-out-side carrying path 6 carrying out the object 16 to be processed after soldering, saturated steam flowing into the carrying-in side and carrying-out side carrying paths 5, 6 from the steam generating tank 4 '. 13
Side walls 31 for introducing the inlet side and outlet side coolers 8 and 9 and the inlet side and outlet side exhaust ports 10 and 11 and the saturated steam 13 generated in the steam generating tank 4 ′ to the upper part of the object 16 to be treated. A side steam outlet 32 for discharging the saturated vapor 13 that has risen in the side wall passage 31 to the upper portion of the object 16 to be processed, and the saturated vapor 13 to the object 16 to be processed.
And a lower steam discharge port 33 that discharges to the lower part of.

2 is a preheating chamber equipped with a preheating heater 14 and 3 is a cooling fan
It is a cooling room equipped with 18. Reference numeral 15 is a conveyor that conveys the object to be processed 16, and 34 is a conveyor guide of the variable conveyor 15 that moves in the width direction in response to a change in the width of the object 16 to be processed.

The apparatus is a drive system including the reflow chamber 1 ', the preheating chamber 2, the cooling chamber 3, the variable conveyor 15, the conveyor guide 34, the sprockets 19, 20, 21 and a drive motor (not shown), and a recovery device. 26, a heat medium recovery system including a hydroxide remover 29, and the like.

The operation of the vapor reflow type soldering device thus configured will be described.

The heat medium 12 accumulated at the bottom of the generation tank 4 ′ is heated by the heater 7 and boils to generate saturated steam 13.

The saturated steam 13 rises to the upper part and is discharged from the lower steam discharge port 33, and partly rises in the side wall passage 31 to the side steam discharge port 32.
Is discharged from above and the object 16 to be processed is heated from above and below, and a part thereof is condensed and liquefied and falls, and is accumulated at the bottom of the steam generation tank 4 '.

The saturated steam 13 that has flowed into the carry-in side transport path 5 and the carry-out side transport path 6 is cooled and liquefied by the carry-in side cooler 8 and the carry-out side cooler 9, and passes through the return pipe 17 to the bottom of the steam generation tank 4 ′. Return. The slightly remaining steam flows from the carry-in side exhaust port 10 and the carry-out side exhaust port 11 into the collecting device 23 through the pipe 22, and is collected by the cooling coil 24 and the demister 25.

The recovered heat medium is subjected to hydroxide removal by the hydroxide remover 26 and returned to the steam generation tank 4 ′ by the pump 27.

On the other hand, the object 16 to be treated, which is heated by the preheater 14 and carried into the reflow chamber 1'from the preheat chamber 2 by the conveyor 15, is heated by touching the saturated steam 13, and the saturated steam 13 in the steam generating tank 4'is heated. The solder is heated and melted by the latent heat of condensation to be soldered.

The object to be processed 16 is gradually cooled into the carry-out side transport path 6, enters the cooling chamber 3, is further cooled by the cooling fan 18, and is carried out of the apparatus.

In this apparatus, the temperature sensor 28 and the temperature controller 29 movably provided in the steam generation tank 4'control the power to the heater 7 through the power controller 30 so that the temperature becomes a predetermined temperature. The amount of steam generated is controlled by controlling the height of the saturated steam 13 in the steam generating tank 4 '.

[Problems to be Solved by the Invention]

In the vapor reflow soldering device as described above, even when the width of the object to be processed is smaller than the maximum allowable width of the device, the saturated vapor amount discharged from the vapor outlet and contacting the object to be processed is Is the same as when the width is the maximum allowable width, which is an extra amount for soldering an object having a small width.

That is, more saturated steam than is necessary for soldering an object having a small width is generated, and the amount thereof increases as the width of the object becomes smaller.

If excess saturated steam flows out of the work-piece carry-in side transport path or the carry-out side carry path, the saturated steam will not rise in the side wall passages and the saturated steam discharge from the side steam discharge port to the upper surface of the work piece. The problem arises that the quantity is reduced.

In particular, when processing a workpiece with a small width in the width direction of the conveyor perpendicular to the conveying direction of the workpiece, insufficient heating of the top surface appears significantly, the solder cannot be melted, and the reliability of soldering There was a problem that it deteriorated.

The present invention has been made to solve the problems in the above-mentioned prior art, and an object of the present invention is to effectively raise saturated steam from the side wall passage and eliminate insufficient heating of the upper surface of the object to be processed, Uniformize the temperature distribution across the width of the substrate,
An object of the present invention is to provide a vapor reflow type soldering device capable of achieving reliability of soldering.

Another object of the present invention is vapor reflow that can improve economic efficiency by suppressing the generation and outflow of excess saturated steam according to the change in the width of the object to be processed, and reducing the heat medium consumption amount. The purpose is to provide a soldering device.

[Means for Solving the Problems]

In order to achieve the above object, the configuration of the vapor reflow soldering device according to the present invention, the saturated vapor of the heat medium is brought into contact with the workpiece conveyed by the conveyor means to heat and melt the solder of the workpiece. A steam generation tank for soldering, a lower steam discharge port that discharges saturated steam to the lower part of the object to be processed in this steam generation tank, and a side wall that guides the saturated steam generated in the steam generation tank to the upper part of the object to be processed. The steam is generated based on the temperature detection result of the passage, the side steam discharge port for discharging the saturated steam rising in the side wall passage to the upper portion of the object to be processed, and the temperature sensor movably provided in the steam generation tank. In a vapor reflow type soldering device having means for controlling the amount of steam generated in the tank, in accordance with a change in the width of the conveyor means, at least the lower steam discharge port of the conveyor means It is provided with a means for opening and closing in the direction.

[Action]

According to the present invention, the shape of the lower vapor discharge port changes according to the width of the conveyor, and it is possible to generate the optimal amount of vapor for soldering the object to be processed, which reduces the consumption of the heat medium. The economical efficiency is improved, and the reliability of soldering of the object to be processed is improved. In particular, by limiting the width of the lower steam outlet to the width of the conveyor, the amount of steam that rises in the side wall passage and flows out from the side steam outlet increases, and the upper surface of the object to be processed is properly heated.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

In the figure, the same reference numerals as those in FIGS. 7 and 8 indicate the same parts as those in the prior art, and thus the description thereof will be omitted.

In the embodiment shown in FIGS. 1 and 2, a lower split shutter 35 is provided as a means for opening and closing in the width direction of the conveyor 15 below the conveyor guide 34 which moves in response to a change in the width of the object to be processed 16, and a lower vapor. The shape of the discharge port 33 is changed.

The operation of the vapor reflow type soldering apparatus of this embodiment having the above-mentioned structure will be described.

For example, if the type of the object 16 to be processed such as a printed wiring board (board) for connecting semiconductor chip parts changes and its width changes,
The conveyor guide 34 moves in the width direction corresponding to the width of the object 16 to be processed. When the conveyor guide 34 moves, the lower split shutter 35 provided below the conveyor guide 34 is pulled out to partially cover the lower steam discharge port 33, and the width of the lower steam discharge port 33 is the width of the workpiece 16. Is equivalent to

The heat medium 12 accumulated at the bottom of the steam generation tank 4 is heated by the heater 7 to evaporate, and the saturated steam 13 thereof is vaporized in the steam generation tank 4
It rises inside and reaches the lower steam outlet 33. Since the lower steam discharge port 33 is covered by the lower split shutter 35 and has the same width as the workpiece 16, the amount of steam flowing out from the lower steam discharge port 33 is higher than that of the side steam passing through the side wall passage 31. The amount of steam flowing out from the discharge port 32 increases. When the amount of steam discharged from the side steam discharge port 32 increases, the steam surface above the object to be processed 16 rises. The temperature sensor 28 senses this and the heater 7 is supplied to the heater 7 via the power controller 30. The applied electric power is adjusted to control the steam surface to be constant.

According to the embodiment shown in FIGS. 1 and 2, the following effects are brought about.

When the width of the object to be processed 16 changes, the width of the conveyor 15 is changed accordingly. Along with this, the width of the lower steam outlet 33 becomes equal to the width of the object 16 to be processed, and the amount of steam discharged from the lower steam outlet 33 necessary for soldering the object 16 is 7th, 8th. It is less than the conventional example shown in the figure. That is, since the amount of surplus steam is reduced, the economical efficiency is improved by saving the electric power of the heater 7 and reducing the heat medium consumption amount.

On the other hand, the amount of steam flowing out from the side steam discharge port 32 through the side wall passage 31 increases, heating of the upper surface of the object to be processed becomes appropriate,
Sufficient heating is performed from above and below the workpiece 16. Therefore, insufficient heating of the upper surface of the object to be processed 16 can be eliminated, the temperature distribution can be made uniform in the width direction of the substrate, and the reliability of soldering can be improved.

Next, FIG. 3 is a sectional view showing the structure of a vapor reflow soldering apparatus according to another embodiment of the present invention, and FIG. 4 is a sectional view taken along the line BB of FIG. Figures 1 and 2 in Figures 3 and 4
The parts having the same reference numerals as those in the figure are the same parts as those in the previous embodiment, and therefore their explanations are omitted.

In the apparatus shown in FIGS. 3 and 4, a telescopic passage 36 continuous with a conveyor guide 34 is added to the side steam outlet 32 on the movable conveyor side of the embodiment shown in FIGS. The member forming the expansion / contraction path 36 is, for example, a bellows member, and is a conveyor guide.
Expands and contracts in accordance with the movement of 34 in the width direction of the conveyor.

The saturated steam 13 generated from the steam generation tank 4A rises in the side wall passage 31 and is discharged from the side steam discharge port 32 to heat the object to be processed 16 from above. At this time, the side wall passage on the movable conveyor side
The saturated steam 13 having risen above 31 expands and contracts as the conveyor guide 34 moves in the width direction. For example, the object 16 is heated from above by flowing out from the side steam discharge port 32 through the expansion / contraction path 36 formed by a bellows member or the like.

According to the embodiment shown in FIGS. 3 and 4, the following effects can be obtained.

Conveyor guide that moves according to the width change of the workpiece 16
The expansion and contraction of the expansion and contraction passage 36, which is continuous with 34, allows the side steam outlet
Since the discharge part of 32 is located above the conveyor guide 34, the discharge of the saturated steam 13 is not hindered by the conveyor guide 34, and the amount per unit time of the saturated steam 13 reaching the upper part of the object 16 to be processed is the first. The amount of steam generated for soldering can be obtained by controlling the electric power to the heater 7 without excess, as compared with the embodiment shown in FIGS. That is, the economical efficiency is improved by reducing the consumption amount of the heat medium.

Further, since the saturated steam 13 is discharged almost simultaneously without being affected by the width of the object to be processed 16 and heats the object to be processed 16, the temperature distribution in the width direction of the object to be processed 16 becomes substantially uniform, and soldering Improves reliability.

Next, FIG. 5 is a sectional view showing the structure of a vapor reflow soldering apparatus according to still another embodiment of the present invention, and FIG. 6 is a sectional view taken along the CC line in FIG. In Figures 5 and 6,
The components having the same reference numerals as those in FIGS. 1 and 2 are the same as those in the previous embodiment, and therefore the description thereof is omitted.

The apparatus shown in FIGS. 5 and 6 is provided with an upper steam outlet 38 in place of the side steam outlet 32 in the embodiment shown in FIGS. 1 and 2, and an upper split shutter connected to a conveyor guide 34 here. 39 is provided.

The saturated steam 13 that has risen in the side wall passage 31 of the steam generation tank 4B spreads in the width direction in the upper passage at the ceiling of the transfer passage, and is discharged from the upper steam discharge port 38 through the rectifying mechanism 37. When the conveyor guide 34 moves in the width direction corresponding to the change in the width of the workpiece 16, the upper and lower divided shutters 39, 35 attached to the conveyor guide 34 are pulled out, and the upper and lower vapor discharge ports 38, 33. Is partially covered, the discharge width corresponds to the width change of the object 16 to be processed, and the vapor amount is controlled to be suitable for the object 16.

According to the embodiment shown in FIGS. 5 and 6, the following effects can be obtained.

The discharge port width of the upper steam discharge port 38 changes in accordance with the width change of the object 16 to be processed by the upper divided shutter 39, so that the amount of saturated steam reaching the upper part of the object 16 per unit time is The amount of vapor is smaller than that of the embodiment shown in FIGS. 3 and 4, and the amount of vapor is appropriate for soldering.

Therefore, the electric power of the heater 7 is saved and the consumption amount of the heat medium is reduced, thereby improving the economical efficiency.

In addition, even for high-density mounted objects, saturated vapor is made to flow out from the top, so there is no obstruction by parts, and
Less likely to be affected by the heat capacity of the object to be processed, the reliability of soldering is improved, and the temperature setting does not have to be changed regardless of the width of the object to be processed, making it easy to set conditions on the work surface. .

〔The invention's effect〕

As described in detail above, according to the present invention, the saturated vapor is effectively increased from the side wall passage, the insufficient heating of the upper surface of the object to be processed is eliminated, and the temperature distribution is made uniform in the width direction of the substrate. It is possible to provide a vapor reflow type soldering device capable of achieving reliability in soldering.

Further, according to the present invention, depending on the width change of the object to be processed, vapor reflow solder that can improve economy by suppressing the generation and outflow of excess saturated vapor and reducing the heat medium consumption amount. An attachment device can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a vapor reflow soldering apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 4 is a cross-sectional view showing the structure of the vapor reflow soldering apparatus according to the embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line BB of FIG. 3, and FIG. 5 is a vapor reflow according to another embodiment of the present invention. FIG. 6 is a cross-sectional view showing the structure of the soldering machine of FIG.
FIG. 7 is a sectional view taken along the arrow C, FIG. 7 is a configuration diagram of a conventional vapor reflow soldering apparatus, and FIG. 8 is a sectional view taken along the arrow DD of FIG. 1 ... Reflow chamber, 4, 4A, 4B ... Steam generation tank, 5 ... Carry-in side transport path, 6 ... Carry-out side transport path, 7 ... Heater,
12 ... Heat medium, 13 ... Saturated steam, 15 ... Conveyor, 16 ...
… Processing object, 32 …… Side vapor outlet, 33 …… Lower vapor outlet, 34 …… Conveyor guide, 35 …… Lower split shutter, 36 …… Expansion passage, 38 …… Upper vapor outlet, 39 ...... Upper split shutter.

Claims (1)

[Claims] 1. A steam generating tank for contacting an object to be processed conveyed by conveyor means with saturated steam of a heat medium to heat and melt solder of the object to be processed, and a saturated steam in the steam generating tank. To the lower part of the object to be processed, a side wall passage for guiding the saturated steam generated in the steam generation tank to the upper part of the object to be processed, and the saturated steam rising in the side wall passage to the upper part of the object to be processed. Vapor reflow type equipped with a side steam discharge port for discharging to, and means for controlling the amount of steam generated in the steam generation tank based on the temperature detection result of a temperature sensor movably provided in the steam generation tank In the soldering apparatus, a vapor reflow type characterized by being provided with means for opening and closing at least the lower steam outlet in the width direction of the conveyor means in accordance with a change in the width of the conveyor means. Soldering equipment.