JP2002319616A - Wafer carrier and method of soldering solar battery wafer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer carrier that can improve the productive efficiency of a solar battery wafer by shortening the soldering time per solar battery wafer and can eliminate the occurrence of cracks in wafers, when the wafers are dipped in a molten solder bath and the occurrence of troubles in carrier transfer of the wafers. SOLUTION: This wafer carrier 20 is composed of a box-like body, which is surrounded by a plurality of metallic side plates 21 and 23 and has openings on its tops side and bottom side; the box-like body has a housing section 22 for housing a plurality of plate-shaped wafers 100, in parallel at intervals in its inside; and the side plates 21 and 23 are surface-treated, so that molten solder does not adhere to the plates 21 and 23, when the box-like body is dipped in the molten solder bath in a state with the body housing the wafers 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wafer carrier and a method for soldering a solar cell wafer using the same.

[0002]

2. Description of the Related Art Conventionally, a solar cell having a light receiving surface electrode formed on one surface of a semiconductor substrate (wafer) having a semiconductor junction having a photovoltaic function and a back surface electrode formed on the other surface is widely used. Used.

The light-receiving surface electrode and the back surface electrode are formed by applying a silver (Ag) paste in a predetermined pattern by screen printing through a pattern mask, and then firing the applied silver paste. You. However, since the light receiving surface electrode and the back surface electrode formed by firing silver paste have relatively high electric resistance, it is necessary to further build up solder thereon (hereinafter, referred to as soldering treatment in this specification). .

Usually, as a method of performing a soldering process, the following solder dip methods (1) and (2) are used, in which a solar cell wafer fired with silver paste is dipped in a molten solder bath and pulled up. (1) A solder dipping apparatus is used in which solar cell wafers are automatically held directly one by one by a holder and immersed in a molten solder bath (for example, JP-A-58-58729 or JP-A-3-145166). reference).

(2) When performing solder dipping of a solar cell wafer, a plurality of solar cell wafers are set on a metal wafer carrier by a transfer machine, and flux application / drying, solder immersion, cleaning, After performing the drying process, the carrier is transported to the transfer / extraction machine by the conveyor after the processing, and the solar cell wafer is taken out from the carrier. As described above, when a plurality of solar cell wafers are set on the wafer carrier and the soldering processing is performed on the set plurality of solar cell wafers at once, the time required for the soldering processing per one solar cell wafer is required. Can be shortened.

[0006]

In the solder dipping method as described in the above (1), each solar cell wafer is directly held by a holder and immersed in a molten solder bath. The time required for the soldering process increases.

[0007] In many cases, the solar cell wafer before soldering is warped due to a difference in pattern between the light receiving surface electrode and the back surface electrode. If the warped solar cell wafer is directly grasped by the holder of the solder dipping device, an excessive force will be applied to a part of the solar cell wafer, causing distortion, and in the worst case, the solar cell wafer will be broken There is. Further, if the holder is insufficiently gripped due to the warpage of the solar cell wafer, the solar cell wafer may be dropped into the molten solder tank.

On the other hand, in the solder dipping method as described in the above (2), when the solar cell wafer is inserted into a slit provided in the wafer carrier by a transfer machine and set, the lower end of the solar cell wafer is made of a metal wafer carrier. The wafer directly hits the lower end of the slit, so that a crack in the wafer due to a biting impact has been a problem.

In addition, when the metal wafer carrier is lifted out of the molten solder bath, excess molten solder does not easily flow down. When the solder remaining at the lower end of the slit solidifies, the soldered solar cell wafer is removed. It may not be possible to remove it from the wafer carrier.

When the wafer carrier having been subjected to the solder dip processing is conveyed to the transfer and unloading machine on the conveyor, the transfer of the wafer carrier is stopped in front of the transfer and unloading machine due to the waiting for the transfer processing, but the conveyor belt is driven. In order to stop only the leading wafer carrier with the stopper slipping the belt with the stopper, the subsequent wafer carriers continuously conveyed by the conveyor are pressed against the stopped leading wafer carrier and mutually stopped. It was a problem to stay bitten.

In this case, the transfer of the leading wafer carrier is stopped not by the stopper but by the stop of the conveyor belt itself, thereby eliminating the connection due to the bite between the wafer carriers. Since it becomes impossible to convey the belt, it was necessary to stop the belt drive by a stopper without slipping on the belt without stopping the belt drive.

The present invention has been made in view of the above circumstances, and in order to reduce the time required for the soldering process per solar cell wafer, a plurality of solar cell wafers are simultaneously transferred to a solder melting tank. An object of the present invention is to provide a wafer carrier that can be immersed and that can eliminate a wafer crack and a carrier transport trouble during a solder dipping process and a method for soldering a solar cell wafer using the same.

[0013]

The present invention comprises a box-like body surrounded by a plurality of side plates made of metal and having upper and lower openings.
The box-shaped body has an accommodation portion for accommodating a plurality of plate-shaped wafers in parallel at spaced intervals, and each side plate accommodates a wafer in the box-shaped body and is immersed in a molten solder bath. The present invention provides a wafer carrier characterized in that a surface treatment is performed so that molten solder does not easily adhere to the wafer carrier.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A wafer carrier according to the present invention may have a side plate made of stainless steel, which may be polished as a surface treatment. Specific examples of stainless steel include SUS304.

Further, the wafer carrier according to the present invention comprises:
The surface treatment may be a treatment of coating with an oxide film or a PFA resin (tetrafluoroethylene-perfluoroalkylvinyl ether copolymer). Specifically, the surface treatment includes an alumite coating treatment. With such a configuration, in any case, the adhesion of the molten solder can be reduced.

In the wafer carrier according to the present invention,
Two side plates of the plurality of side plates are opposed to each other so that the distance between them becomes narrower from top to bottom, and a plurality of parallel slits having an upper end and a lower end are formed to form a housing portion, The wafer may be accommodated by being inserted into slits of the opposed side plates.

In the wafer carrier according to the present invention, each side plate having the slit may be bent at a line crossing each slit between the upper edge and the lower edge.

With this configuration, the interval between the slits facing each other is narrower than in a case where the side plate is not bent, so that the wafer accommodated in the wafer carrier receives a buoyancy during the solder dip and rises to some extent. Also become difficult to get out of the slit. Therefore, the wafer lifted by the buoyancy can not be reliably supported by the slits and tilts, so that it is possible to prevent the adjacent wafers from contacting and joining. As a result, when taking out the wafer from the wafer carrier, an excessive force is applied to the wafer, thereby preventing the wafer from being broken.

In the wafer carrier according to the present invention, each slit may have a width near an upper end thereof larger than a width near a lower end. With this configuration, the wafer can be easily inserted into the slit.

Further, the wafer carrier according to the present invention comprises:
A bar may be further provided across the vicinity of the lower end of each slit to support the lower end of the accommodated wafer. According to this structure, it is possible to prevent the lower end of the accommodated wafer from breaking into the lower end of the slit and breaking.

The bar is preferably made of PEEK resin, PFA resin or PTFE resin. Because PEEK resin (polyetheretherketone), P
This is because the FA resin or the PTFE resin (polytetrafluoroethylene) has no solder adhesion and has a soft contact with the wafer, so that it is suitable as a bar material.

The bar may be band-shaped, and the cross section of the upper edge may be semicircular and the cross section of the lower edge may be tapered. With this configuration, when the wafer carrier is pulled out of the molten solder bath, the molten solder does not accumulate in the bar and solidify, and the molten solder attached to the bar easily flows down. Further, water droplets adhered to the bar during washing and drying described later easily flow down.

Further, the bar may be provided outside or inside each of the pair of side plates provided with slits. Specifically, the bar may be attached with a gap between the bar and the side plate of the carrier. With such a configuration, the bar does not scoop up the molten solder when the wafer carrier is pulled out of the molten solder bath.
Furthermore, the accumulation of water droplets during washing and drying described below is eliminated,
It becomes easier to dry. Note that the bar may have a shape other than the above shape, and for example, may be a round bar-shaped bar.

Further, in the wafer carrier according to the present invention, the side plates may each be provided with a projection having a flat tip, and the projections may be configured to come into contact with each other when a plurality of wafer carriers are moved by the conveyor. .
This is in consideration of the case where a plurality of wafer carriers according to the present invention are transported by a belt conveyor.

That is, when soldering is performed on a wafer using an automatic solder dipping apparatus, the following steps are performed. The wafer is loaded into the wafer carrier by a transfer machine, and flux coating, drying, immersion in a molten solder tank, washing, and drying are performed by an automatic solder dipping device, and the wafer carrier is transported to a wafer transfer and removal machine by a belt conveyor. To remove the wafer from the wafer carrier.

Here, in the above process, the transfer of the wafer carrier is stopped just before the wafer transfer / unloading machine while waiting for the wafer unloading process. However, the belt of the belt conveyor is kept driven in order to quickly convey the subsequent carrier, and only the first wafer carrier is forcibly stopped by a stopper provided on the belt conveyor. In other words, the wafer carrier whose conveyance has been stopped slips on the belt conveyor.

However, in this state, the wafer carriers arranged front and rear on the belt conveyor are pressed against each other, so that not only is the wafer carrier not well aligned on the belt conveyor,
In the worst case, they are intertwined with each other. Therefore, in the wafer carrier of the present invention, such a phenomenon is prevented by providing the above-mentioned protrusion.

That is, if each wafer carrier is provided with a projection having a flat tip, when the wafer carrier is forcibly stopped while slipping on the belt conveyor, the projections of the front and rear wafer carriers are mutually connected. The contact allows the wafer carrier to be neatly aligned on the belt conveyor.

The above-mentioned projections may be provided at two locations near the upper end and near the lower end of two opposing side plates not provided with slits. In other words, if the protrusions are not provided on the entire surface before and after the wafer carrier, but are provided only at two locations near the upper end and the lower end of the side plate, heat is stored in the wafer carrier when the wafer carrier is immersed in the molten solder bath. Heat is reduced,
Temperature fluctuation in the molten solder bath can be reduced.

In another aspect of the present invention, the wafer is a solar cell wafer having a silver electrode pattern formed on the front and back surfaces, and a plurality of solar cell wafers are accommodated in a wafer carrier according to the present invention. Another object of the present invention is to provide a method for soldering a solar cell wafer, which is immersed in a molten solder bath and thereby solders the electrode pattern.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. The present invention is not limited by the embodiment. Note that the same reference numerals are used for members commonly used in the following embodiments.

Embodiment 1 FIG. 1 shows a wafer carrier according to Embodiment 1 of the present invention.
This will be described based on Nos. 1 is a perspective view of a wafer carrier according to Embodiment 1 of the present invention, FIG. 2 is a front view of the wafer carrier shown in FIG. 1, FIG. 3 is a partially cutaway right side view of the wafer carrier shown in FIG. FIG. 4 is a front view showing a state where a solar cell wafer is accommodated in the wafer carrier shown in FIG.

As shown in FIGS. 1 to 4, the wafer carrier 10 according to the first embodiment of the present invention is surrounded by two metal side plates 1 and two metal end plates 3 and has openings vertically. The box-shaped body has a slit 2 for accommodating a plurality of plate-shaped solar cell wafers 100 in parallel with a space therebetween, and each side plate 1, 3 is formed in the box-shaped body. The surface treatment is performed so that the molten solder does not easily adhere when the solar cell wafer 100 is housed in the molten solder bath (not shown).

More specifically, as shown in FIGS. 1 to 3, the box-shaped body is composed of two opposed side plates 1 and two opposed end plates 3. The two end side plates 3 are fixed to the outer upper beam 5 and the outer lower beam 6 with fastening screws 7 so as to face each other at an interval. The two lateral plates 1 are formed such that an inner upper beam portion 11 and an inner lower beam portion 12 are formed on the upper edge and the lower edge of each lateral plate 1 so that the distance between them becomes smaller from top to bottom. Are fixed to each end side plate 3 with fastening screws 7. As shown in FIG. 2, the interval W1 between the upper edges of the two lateral side plates 1 facing each other is set to be slightly larger than the size of the solar cell wafer 100 to be accommodated.

The horizontal plate 1 is provided with a plurality of slits 2 so that a plurality of solar cell wafers 100 can be vertically arranged in parallel and accommodated in a wafer carrier 10. Further, the end side plate 3 does not hinder the flow of the molten solder into and out of the wafer carrier 10 when the wafer carrier 10 is immersed in the molten solder bath, and also reduces the amount of heat stored in the wafer carrier 10. Is formed with a square hole 4. The lateral plate 1, the end plate 3, the outer upper beam 5, the outer lower beam 6, and the fastening screw 7 are so formed that the solder hardly adheres thereto.
It is made of a polished stainless steel such as SUS304. Note that, instead of the above stainless steel, another metal having an oxide film formed on the surface may be used.

The wafer carrier 1 having such a configuration
When a plurality of solar cell wafers 100 are housed in a bath and immersed in a molten solder bath, the soldering of the plurality of solar cell wafers 100 can be performed simultaneously. Therefore, the time required for the soldering process per solar cell wafer is reduced, and the production efficiency of the solar cell wafer is improved.

Further, since it is not necessary to directly hold the solar cell wafers one by one with the holder of the solder dipping device as in the conventional case, the solar cell wafer may be broken even if the solar cell wafer is warped. Absent. Further, the solar cell wafer is not dropped into the molten solder tank due to insufficient gripping of the solar cell wafer by the holder.

Second Embodiment Next, a wafer carrier according to a second embodiment of the present invention will be described with reference to FIGS. 5 is a perspective view of a wafer carrier according to Embodiment 2 of the present invention, FIG. 6 is a front view of the wafer carrier shown in FIG. 5, and FIG. 7 is a partially cutaway right side view of the wafer carrier shown in FIG. .

As shown in FIGS. 5 to 7, the wafer carrier 20 according to the second embodiment of the present invention is surrounded by two metal side plates 21 and two metal end plates 23 and has openings vertically. The box-shaped body has a slit 22 therein for accommodating a plurality of plate-shaped solar cell wafers 100 in parallel at intervals, and each side plate 21 and 23 is provided in the box-shaped body. When the solar cell wafer 100 is accommodated and immersed in a molten solder bath (not shown), the surface treatment is performed so that the molten solder does not easily adhere.

More specifically, as shown in FIGS. 5 to 7, the box-shaped body is composed of two opposed side plates 21 and two opposed end plates 23. The two end side plates 23 are fixed to the outer lower beam 6 with fastening screws 7 so as to face each other at an interval. Each of the two lateral plates 21 has an upper beam portion 31 and an inner lower beam portion 32 formed at the upper edge and the lower edge of each lateral plate 21 so that the distance between them becomes narrower from top to bottom. Both ends are fixed to each end side plate 23 with fastening screws 7. As shown in FIG. 6, the interval W2 between the upper edges of the two side plates 21 facing each other is set to be slightly larger than the size of the solar cell wafer 100 to be housed.

The horizontal side plate 21 includes a plurality of solar cell wafers 10.
A plurality of slits 22 are provided so that 0s can be accommodated in the wafer carrier 20 while being arranged vertically and parallel. Further, the horizontal side plate 21 has a bent portion 33 bent on a line crossing each slit 22 near the upper end thereof. In addition, the width of the upper end portion 29 of each slit 22 is wider than other portions so that the solar cell wafer 100 can be easily inserted into the slit 22. Here, the distance W1 between the upper edges of the first embodiment shown in FIG. 2 and the second embodiment shown in FIG.
Are substantially the same. Therefore, in the wafer carrier 20 according to the second embodiment, the interval between the slits 22 facing each other is narrower than that in the first embodiment, particularly, the interval from the bent portion 33 to the bottom.

By providing the bent portion 33 on each of the side plates 21, even if the solar cell wafer 100 accommodated in the wafer carrier 20 is lifted to some extent by the buoyancy during the solder dip, it is difficult for the solar cell wafer 100 to fall out of the slit 22. Therefore, the solar cell wafer that has been lifted by the buoyancy cannot be reliably supported by the slits and is inclined, so that it is possible to prevent the adjacent solar cell wafers from contacting and joining. As a result, when taking out the solar cell wafer from the wafer carrier, it is possible to prevent the solar cell wafer from being broken due to excessive force.

Note that the end side plate 23 is
Is immersed in a molten solder bath, the wafer carrier 20
Square holes 24 so as not to hinder the flow of molten solder into and out of
Are formed.

Further, the lateral plate 21, the end plate 23, the outer lower beam 6
The fastening screws 7 are made of stainless steel such as SUS304 which has been polished so that solder does not easily adhere thereto. Further, instead of the above stainless steel, another metal whose surface has been subjected to an oxide film treatment may be used.

Wafer carrier 2 having such a configuration
When a plurality of solar cell wafers 100 are housed in a bath and immersed in a molten solder bath, the soldering of the plurality of solar cell wafers 100 can be performed simultaneously. Accordingly, the time required for the soldering process per solar cell wafer is reduced, and the production efficiency of the solar cell wafer is improved.

Third Embodiment Next, a wafer carrier according to a third embodiment of the present invention will be described with reference to FIGS. 8 is a perspective view of a wafer carrier according to Embodiment 3 of the present invention, FIG. 9 is a front view showing a state where a solar cell wafer is housed in the wafer carrier shown in FIG. 8, and FIG. 10 is a wafer carrier shown in FIG. 11 is a plan view of the bar shown in FIG. 10, and FIG. 12 is a right side view of the bar shown in FIG.

As shown in FIGS. 8 and 9, the wafer carrier 40 according to the third embodiment of the present invention has a bar which crosses the vicinity of the lower end of each slit 2 to support the lower end of the solar cell wafer 100 to be accommodated. 54 are provided.

More specifically, as shown in FIG. 9, the bar 54 is attached with a gap 55 between the bar 54 and the side plate 1. In the third embodiment, the gap 55 is provided outside the side plate 1.
Is opened, but a gap may be provided inside the horizontal side plate 1 so as to be attached. The bar 54 is formed of a heat-resistant resin having no solder adhesion and having a soft contact with the solar cell wafer 100. In the third embodiment, the bar 54
Although the PEEK resin is used as the material of the above, a PFA resin or a PTFE resin which is also a heat-resistant resin may be used as the material.

As shown in FIGS.
Is band-shaped, the cross section of the upper edge 56 is semicircular, and the lower edge 5
7 is tapered in cross section. By providing such a bar 54 in the wafer carrier 40,
The housed solar cell wafer 100 is prevented from breaking into the lower end 8 of the slit 2 (see FIG. 3).
Further, when the wafer carrier 40 is pulled up from the molten solder bath, the molten solder does not accumulate in the bar 54 and easily flows down. Further, when the wafer carrier 40 is washed, water droplets easily flow down and dry easily.
Other configurations are the same as those in the first embodiment.

The wafer carrier 40 shown in the third embodiment has a configuration in which the bar 54 is attached to the wafer carrier 10 in the first embodiment, but the bar 54 is attached to the wafer carrier 20 in the second embodiment. Is also good.

Embodiment 4 Next, a wafer carrier according to Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 13 is a perspective view of a wafer carrier according to Embodiment 4 of the present invention, and FIG. 14 is an explanatory view showing a state where the wafer carrier shown in FIG. 13 is forcibly stopped in a state of slipping on a belt conveyor. is there.

As shown in FIG. 13, in the wafer carrier 60 according to Embodiment 4 of the present invention, each of the pair of end side plates 63 has a projection 79 having a flat portion 78 at the tip.

More specifically, as shown in FIG. 13, the protruding portions 79 are provided near the upper end and the lower end of the end plate 63, respectively, and the plate-like portions extending partially from the vicinity of the upper end and the lower end are provided at the end. It has a shape that is bent at a right angle to the side plate 63. Other configurations are the same as those of the third embodiment.

The projection 79 is connected to the wafer carrier 6.
0, when the plurality of wafer carriers 60 are forcibly stopped while slipping on the belt conveyor 200, as shown in FIG. Come into contact. For this reason, the front and rear wafer carriers 60 are
Therefore, the solar cell wafer 100 can be smoothly removed from the wafer carrier 60 using an automatic transfer / extractor (not shown) or the like.

[0055]

According to the present invention, each side plate of the wafer carrier is subjected to a surface treatment so that the molten solder does not adhere. Therefore, a plurality of wafers are accommodated in the wafer carrier and the wafer carriers are immersed in the molten solder bath. As a result, the time required for the soldering process per wafer can be shortened, and the wafer cracking and carrier transport trouble during the solder dip process can be eliminated.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wafer carrier according to Embodiment 1 of the present invention.

FIG. 2 is a front view of the wafer carrier shown in FIG.

FIG. 3 is a partially cutaway right side view of the wafer carrier shown in FIG. 1;

FIG. 4 is a front view showing a state where a solar cell wafer is accommodated in the wafer carrier shown in FIG. 1;

FIG. 5 is a perspective view of a wafer carrier according to Embodiment 2 of the present invention.

FIG. 6 is a front view of the wafer carrier shown in FIG. 5;

FIG. 7 is a partially cutaway right side view of the wafer carrier shown in FIG. 5;

FIG. 8 is a perspective view of a wafer carrier according to Embodiment 3 of the present invention.

9 is a front view showing a state where a solar cell wafer is accommodated in the wafer carrier shown in FIG.

FIG. 10 is a front view of a bar provided on the wafer carrier shown in FIG. 8;

FIG. 11 is a plan view of the bar shown in FIG. 10;

FIG. 12 is a right side view of the bar shown in FIG. 10;

FIG. 13 is a perspective view of a wafer carrier according to Embodiment 4 of the present invention.

FIG. 14 is an explanatory view showing a state where the wafer carrier shown in FIG. 13 is forcibly stopped in a state of slipping on a belt conveyor.

[Explanation of symbols]

 6 Outer lower beam 20 Wafer carrier 21 Side plate 22 Slit 23 End plate 24 Square hole 29 Upper end 31 Upper beam 32・ ・ ・ Inner lower beam part 33 ・ ・ ・ Bent part 100 ・ ・ ・ Solar cell wafer

Continued on the front page F term (reference) 4E080 AA10 DA10 5F031 CA04 DA03 EA01 EA02 EA06 EA18 HA72 MA21

Claims (13)

[Claims] 1. A box-shaped body surrounded by a plurality of side plates made of metal and having openings at upper and lower sides, and the box-shaped body houses therein a plurality of plate-shaped wafers in parallel with a space therebetween. A wafer carrier having a portion, wherein each side plate is surface-treated so that molten solder does not adhere when a wafer is accommodated in a box-shaped body and immersed in a molten solder bath. 2. The wafer carrier according to claim 1, wherein the side plate is made of stainless steel and polished as a surface treatment. 3. The wafer carrier according to claim 1, wherein the surface treatment is a treatment of coating with an oxide film or a PFA resin. 4. A housing portion in which two side plates of the plurality of side plates face each other such that a distance between them becomes narrower from top to bottom, and a plurality of parallel slits having an upper end and a lower end are formed. The wafer carrier according to any one of claims 1 to 3, wherein each wafer is inserted into a slit of an opposite side plate and accommodated. 5. The wafer carrier according to claim 4, wherein each side plate having the slit formed is bent at a line crossing each slit between an upper edge and a lower edge thereof. 6. The wafer carrier according to claim 4, wherein each slit has a width near an upper end thereof larger than a width near a lower end thereof. 7. The wafer carrier according to claim 4, further comprising a bar crossing a vicinity of a lower end of each slit to support a lower end of the accommodated wafer. 8. The wafer carrier according to claim 7, wherein the bar is made of a PEEK resin, a PFA resin, or a PTFE resin. 9. The bar has a band shape, a cross section of an upper edge portion is semicircular, and a cross section of a lower edge portion is tapered.
Or the wafer carrier according to 8. 10. The bar is provided inside or outside each of a pair of side plates provided with slits.
10. The wafer carrier according to any one of 9 above. 11. The side plate is provided with projections each having a flat tip, and the projections come into contact with each other when a plurality of wafer carriers are moved by a conveyor.
A wafer carrier according to any one of the above. 12. The wafer carrier according to claim 11, wherein the projecting portions are provided at two positions near the upper end and near the lower end of two opposing side plates not provided with slits. 13. The wafer is a solar cell wafer having an electrode pattern made of silver on the front and back surfaces, and accommodates a plurality of solar cell wafers in the wafer carrier according to any one of claims 1 to 12. Immersed in the molten solder bath,
A method for soldering a solar cell wafer, whereby a soldering process is performed on the electrode pattern.