JP2009016436A - Thin plate processing method, and thin plate processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method of a thin plate reduced in strength degradation by the reduced thickness of the thin plate by removing a damaged part at an end of the thin plate. <P>SOLUTION: This method is used for processing a thin plate having a damaged part in the vicinity of an end surface thereof, and including at least either of a metal material and a semiconductor material. In the thin plate processing method, the vicinity of the end surface of the thin plate is immersed in a processing liquid such as an etching liquid, and thereafter the damaged part is removed by washing the etching liquid out. A processing device of a thin plate is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin plate processing method and a thin plate processing apparatus used for manufacturing a solar cell, and more particularly to a thin plate processing method and a thin plate processing apparatus characterized by etching a damaged portion at an end of a thin plate.

A method for slicing an ingot is common as a method for producing polycrystalline silicon for solar cells. As another technique, Patent Document 1 discloses a method for producing thin silicon that does not require a slicing step. In this technique, a surface layer portion of a base plate is immersed in a silicon melt in a crucible, and the silicon melt is solidified on the surface of the base plate to produce thin plate silicon.
JP 2004-331429 A

  This thin silicon plate is cut using a laser or the like and shaped into a product size. Due to this cutting process, a damaged portion may remain on the end face of the thin silicon sheet shaped to the product size. If the damaged portion remains in the thin silicon plate, it may cause the thin plate to break when an electrode is formed for a solar cell. As a method for removing the damaged portion, a method of etching thin silicon with an alkali or acid aqueous solution is generally used.

  In the case of etching the entire thin plate having a damaged portion on the end face, the region having a small damaged portion is etched more than necessary, so that a locally thinned region is generated, which causes cracking. Further, if the etching amount is reduced in order to prevent thinning, the damaged portion remains on the thin plate and causes cracking.

  The present invention solves the above-mentioned problems, and relates to a thin plate processing method and a processing apparatus for removing a damaged portion in the thin plate and reducing a reduction in strength due to thinning of the thin plate.

  The present invention relates to a processing method for a thin plate including at least one of a metal material and a semiconductor material having a damaged portion near an end surface, and the damaged portion is removed by immersing the vicinity of the end surface of the thin plate in a processing solution. This is a thin plate processing method. Here, the treatment liquid is preferably an etching liquid.

  Further, the present invention provides a thin plate holding container capable of accommodating a thin plate so that a main surface thereof is substantially vertical, and the holding container capable of moving the holding container by a predetermined distance in the vertical direction and the horizontal direction. A container moving means; a processing container in which the holding container is carried in and out by the moving means and containing a processing liquid; and a holding container is carried in and out after processing in the processing container and contains a cleaning liquid. Rotating a container capable of immersing the vicinity of the other end surface of the thin plate in a processing solution by rotating the holding container by a predetermined angle in conjunction with the moving means. The present invention relates to a thin plate processing apparatus having means.

  Here, the treatment liquid is preferably an etching liquid. The thin plate holding container preferably includes a hooking portion that can engage with the moving means.

According to the present invention, since a thin plate having a damaged portion on an end face is effectively etched only in the damaged portion region, a locally thinned region does not occur and the cause of cracking can be reduced. In addition, since a plurality of thin plates can be stored in the holding container, the thin plate can be quickly processed, and the productivity is improved.

  Embodiments of a thin plate processing method and a thin plate processing apparatus of the present invention will be described below with reference to the drawings.

<Thin plate holding container>
FIG. 1A shows a schematic side view of a holding container 210 containing a plurality of thin plates 201. FIG. 1B is a schematic front view of the holding container 210 in which the thin plate 201 is stored.

  In the present invention, productivity can be improved by storing a plurality of thin plates in a holding container and simultaneously processing such as etching. The thin plate 201 is disposed in a substantially vertical direction in the holding container, and a damaged portion of the thin plate is located near the end portion or a part of the end portion. When the holding container is immersed in a processing container described later, the damaged portion is disposed so as to be immersed in the processing liquid. Here, the term “substantially vertical” means that arranged in an angle range of ± 40 ° in the vertical direction. The “near end face” of the thin plate refers to an end face region within about 30% of the vertical and horizontal dimensions of the thin plate.

  The holding container 210 is preferably provided with a container lid 211 at the top thereof. The container lid 211 prevents the thin plate from floating due to the buoyancy of the processing liquid during processing such as etching. The structure of the holding container 210 is not particularly limited, but the structure can be changed as appropriate so that the thin plate can be stored. A hook portion 210A that can be engaged with a holding rod 220, which is a part of the moving means of the thin holding container, is provided. The structure and shape of the hooking portion 210A are not particularly limited, but are formed as a part of a frame that forms the bottom, side, and top of the holding container as shown in FIGS. 1 (A) and 1 (B). A protrusion is preferred. A pair of holding rods 220 engaged with the protrusions can be moved in the vertical direction and the horizontal direction on the side surface of the holding container 210.

  FIG. 1B shows a schematic view from the front of the holding container 210, that is, the direction in which the holding container is held by a pair of holding rods 220. Here, the holding bar 220 is omitted.

  The holding container is preferably formed with a wide gap or window on the outer frame of the holding container so that the processing liquid and the cleaning liquid can easily penetrate into the holding container and come into contact with the surface of the thin plate 201 accommodated therein. Therefore, a wide window is formed even when the outer frame is formed of a rod-shaped body or a plate-shaped body. In FIGS. 1A and 1B, a portion where the outer frame of the holding container is painted black indicates a portion where the inner and outer sides of the holding container are blocked.

<Processing container>
Next, FIG. 2A is a schematic view showing a state in which the holding container is arranged in a processing container containing a processing liquid. In the figure, a processing container 202 contains a processing liquid 204 therein. Further, the processing vessel 202 is provided with a heater 206 for heating the processing liquid to a predetermined temperature. The etching rate can be adjusted by adjusting the temperature of the etching solution. In the present invention, an etching solution is preferably used as the processing solution for the thin plate. As the etching solution, an acid or alkali solution can be used when the thin plate 201 is made of silicon.

  Here, by controlling the elevating mechanism of the moving means, the height of the immersion surface of the thin plate in the processing liquid is appropriately adjusted according to the end position of the damaged portion of the thin plate.

<Movement means>
Here, the “moving means” means moving means for carrying the holding container into the processing container, moving means for carrying the holding container out of the processing container and carrying it into the cleaning container described later, and cleaning the holding container. Includes moving means for unloading from the container.

  In FIG. 2 (A), the moving means for carrying the holding container into the processing container holds the holding container 210 by engaging the holding bar 220 provided in the moving means with the hooking portion 220 of the holding container 210. It moves in the direction of the arrow P0 and is placed in the processing container. The mechanism of the moving means is not limited, and for example, a mechanism using a guide rail, a mechanism using a rotating body, or a mechanism using a structure such as a robot arm can be used.

  An embodiment of the moving means of the present invention is shown in FIG. 4 as an example of moving means using a guardrail. In the figure, the moving means 420 includes an elevating mechanism 412 attached to a slide body 411 that moves (runs) along the horizontal operation rail 410. The rotating mechanism 414, the rotating support column 415 operated (rotated) by the rotating mechanism 414, and the pedestal supporting column portion 416 are suspended. A holding rod 220 (not shown) that holds the holding container 210 is connected to the pedestal column 416. The horizontal operation rail 410 is not particularly limited. For example, the horizontal operation rail 410 may form a trajectory extending in the horizontal direction, or a shallow U-shape so that the holding container 210 can move in the direction of the processing container 202 above the processing container 202. A shaped track may be formed.

  The horizontal movement of the holding container 210 is performed by moving the slide body 411 along the horizontal operation rail 410 to move the entire mechanism suspended by the lifting mechanism 412 and the suspension column 413 in the horizontal direction. The movement in the vertical (lifting / lowering) direction is performed by moving the entire lifting / lowering mechanism 412 in the vertical direction on the entire mechanism suspended from the suspension column 413. The rotation operation is performed by the rotation mechanism 414.

  In the present invention, moving means for carrying the holding container 210 into the processing container 202, moving means for carrying the holding container 210 out of the processing container 202 and carrying it into a cleaning container 203 described later, and further holding the holding container 210 as a washing container Any of the moving means for unloading from 203 can be performed by the moving means.

  For example, the horizontal operation rail 410 is caused to travel so that the holding container 210 can be moved in the horizontal direction and disposed above the processing container 202. The holding container is immersed in the processing liquid 204 by lowering the entire mechanism suspended from the lifting mechanism 412 and the suspension column 413 from above the processing container 202.

Next, the elevating mechanism 412 is raised, and the holding container 210 is detached from the processing liquid 204. Thereafter, the holding container is unloaded from the mobile to the processing vessel of the arrow P ₁ the direction of FIG. 2 (A), is further conveyed into the washing container moves in the arrow P ₂ direction in FIG. 2 (B). Here, the horizontal movement and the lifting operation can be performed by mutually independent control mechanisms. As a control mechanism, for example, a personal computer can be programmed with a horizontal movement command, a lifting / lowering movement command, and a tilting motion command, and transmitted to the controller to realize an arbitrary trajectory as programmed. Can do.

<Washing container>
In the present invention, the thin plate processed by etching or the like is carried into the cleaning container 203 while being stored in the holding container 210. The thin plate is cleaned with a processing liquid 205 such as an etch solution by a cleaning liquid 205 contained in a cleaning container 203. Here, water, alcohol, an organic solvent, or the like can be used as the cleaning liquid.

<Rotating means>
In the present invention, the processing container and / or the cleaning container includes a side surface, an upper surface of the holding container, and
A rotating means capable of rotating the bottom surface is provided.

  An outline of the rotating means in the cleaning container will be described with reference to FIGS. The cleaning container 203 includes container rotating means that can rotate the holding container by a predetermined angle after cleaning the thin plate. Specifically, a bottom convex portion 203C is provided at the bottom of the cleaning container. After cleaning, the holding container is rotated in the direction of arrow S around the bottom convex portion 203C by pressing the side surface of the holding container 210 with the holding rod 220. That is, the hooking portion 210A of the holding container 210 and the bottom convex portion 203A of the processing container are in contact with each other, and the holding container 210 rotates 90 degrees in the arrow S direction and rotates to the left side of the processing container 203. Note that the rotation direction of the holding container is adjusted so that only the end faces of the thin plate are immersed.

  As a result, the bottom frame T2 that has been immersed in the processing liquid in the holding container moves to the vertical side frame T2 'after rotation. On the other hand, the side frame T1 that has not been immersed in the treatment liquid moves to T1 'after rotation. Since the positions of the side frame and the bottom frame of the holding container change with rotation, and the position of the end face of the thin plate also changes accordingly, all four of the thin plate can be obtained by rotating the holding container four times (360 degrees). The edge of the surface is cleaned.

  As described above, the rotating means has been described as the cleaning container, but the same can be applied to the processing container. The rotating means is preferably provided in at least one of the processing container and the cleaning container. By using such a rotating means, an etching process and a cleaning process in the vicinity of the four end faces of the thin plate can be effectively performed.

<Manufacturing method of thin plate>
The manufacturing method of the thin plate used with the manufacturing method of this invention is demonstrated based on FIG. FIG. 5 is a schematic view of a thin plate manufacturing apparatus. Here, the thin plate manufacturing apparatus is an apparatus that manufactures a thin plate by a dipping process in which the surface layer portion of the base plate is immersed in the melt and the thin plate formed by the solidification of the melt is adhered to the surface of the base plate. As shown in FIG. 5, the thin plate manufacturing apparatus includes a crucible 101 and an immersion apparatus 120. The crucible 101 holds the melt 102 inside. The dipping device 120 immerses the base plate 104 in the melt 102 in the crucible 101.

  The crucible 101 is disposed in a main chamber (not shown). The main chamber is preferably provided with a member that can be evacuated or filled with an inert gas, for example, so that highly reactive raw materials can be dissolved. For example, an inert gas such as argon is introduced and maintained at a pressure slightly lower than atmospheric pressure (for example, 700 Torr). When argon gas is used, when exhausting, silicon oxide and other dusts are removed through a filter or the like, and are used in a circulating manner. Further, the main chamber may have a raw material replenishment mechanism (not shown) of the melt 102.

  The melt 102 is not particularly limited as long as it is a thin plate material, but preferably contains at least one of a metal material and a semiconductor material in view of the use of the thin plate. For example, as the melt 102, a semiconductor material such as silicon, germanium, gallium, arsenic, indium, boron, antimony, zinc, or tin, or a metal material such as aluminum, nickel, or iron can be used. As the melt 102, a silicon melt is generally used.

  In order to maintain the temperature of the melt 102, it is preferable that the heating means 103 is disposed at all or part of the periphery of the crucible 101. The heating means 103 is not particularly limited, but a general method for melting a metal or semiconductor material, such as resistance heating, induction heating, or infrared heating, can be used.

The dipping device 120 can use, for example, a mechanism that uses a guide rail, a mechanism that uses a rotating body, a mechanism that uses a structure such as a robot arm, or the like. Specifically, the dipping device 120 includes an elevating mechanism 112 attached to a slide body 111 that operates (runs) along the horizontal operation rail 110, and the elevating mechanism 112 is installed on the suspension column 113 and the suspension column 113. The rotating mechanism 114, the rotating column 115 operated by the rotating mechanism 114, and the pedestal column 116 are suspended. A pedestal 117 that holds the base plate 104 is connected to the pedestal support 116.

  The horizontal operation rail 110 may form a track extending in the horizontal direction, for example, and forms a shallow U-shaped track on the crucible 101 so that the pedestal 117 approaches the melt 102 on the melt 102. You may do it. The pedestal 117 has an engagement groove 117 a that engages with the base plate 104 at the center. The base plate 104 has a hook-shaped protrusion 104a on the back surface, and the hook-shaped protrusion 104a and the engaging groove 117a of the pedestal 117 are engaged, and both are integrated. The surface 104b opposite to the surface facing the pedestal 117 in the base plate 104 is a surface for manufacturing a thin plate, and is flat.

  The material of the base plate 104 preferably has sufficient heat resistance that is not easily damaged by immersion in the high-temperature melt 102. For example, when a silicon melt is used as the melt 102, it is preferable to use carbon as the material of the base plate 104 from the viewpoint of heat resistance. In addition, when using a silicon melt as the melt 102, the silicon melt is a high temperature of 1400 ° C. to 1500 ° C., and also includes silicon deposition, so that the immersion device 120 such as a horizontal operation rail is protected. It is preferable to dispose a heat insulating or cooled shielding plate on the crucible 101.

  The horizontal movement of the base plate 104 is performed by moving the slide body 111 along the horizontal operation rail 110 to move the entire mechanism suspended from the lifting mechanism 112 and the suspension column 113 in the horizontal direction. The movement in the vertical (lifting / lowering) direction is performed by moving the entire lifting / lowering mechanism 112 suspended in the suspension column 113 in the vertical direction. The rotation operation is performed by the rotation mechanism 114. Specifically, the base plate 104 is moved in the horizontal direction, and the horizontal operation rail 110 is caused to travel so that it can be disposed above the melt 102 in the crucible 101.

  Then, by lowering the entire mechanism suspended from the elevating mechanism 112 and the suspension column 113 from above the melt 102, the surface layer portion of the base plate 104 is immersed in the melt 102. As a result, silicon in the melt 102 adheres to the surface 104 b of the base plate 104. Next, the elevating mechanism 112 is raised, and the base plate 104 is detached from the melt 102. During this time, the horizontal movement, the raising / lowering operation and the base plate tilting operation are operated by mutually independent control mechanisms. As a result, the base plate 104 is immersed in the melt 102 in an arbitrary orbit and inclined state, moves in the melt 102, and is detached from the melt 102.

  As a control mechanism, for example, a personal computer can be programmed with a horizontal movement command, a lifting / lowering movement command, and a tilting motion command, and transmitted to the controller to realize an arbitrary trajectory as programmed. Can do. Furthermore, since the liquid level gradually drops when a thin plate is continuously produced, and the liquid level rises when a raw material is added, the control mechanism has an immersion track of the base plate 104 in accordance with the liquid level position. It is preferable to have a function capable of adjusting. Note that one motor is assigned to each of the horizontal movement, the raising / lowering movement, and the tilting movement, and they are individually driven by a total of three motors.

The program controls the three independent movements (operations) so that a silicon thin plate having a predetermined thickness can be obtained with respect to fluctuations in the liquid level of the melt 102 and fluctuations in the thickness of the base plate 104. Then, after separating from the melt 102, the base plate 104 is moved in the horizontal direction (becomes horizontal motion), and the base plate to which silicon adheres is removed from the base 117 at a position away from the crucible 101. A silicon thin plate can be manufactured by separating silicon from the base plate to which the silicon adheres. Note that it is preferable that the base plate to which silicon adheres is cooled and then separated into the base plate 104 and the silicon thin plate.

  Here, in order to adjust the shape of the silicon thin plate, the periphery of the thin plate may be cut. As a cutting method, a diamond cutter or a laser can be used. However, damage due to cutting remains in the thin plate near the cut surface of the thin plate. Therefore, in order to improve the strength of the thin plate, it is necessary to remove a damaged portion near the end portion of the thin plate by an etching process or the like. The removal of the damaged part is performed by the method described above.

  Based on the embodiment of the present invention, the effect when only the damaged portion of the end face of the silicon thin plate is etched will be described in detail. A silicon thin plate was produced by the method shown in FIG. 5, and the thin plate was shaped with a laser. The size of the thin plate is 155 mm × 155 mm × 370 μm. As an etching solution, 18 liters of a 3 mass% sodium hydroxide aqueous solution at 87 ° C. was used. Five silicon thin plates were stored in the holding container. Etching conditions are as follows.

(1) The entire thin plate was etched for 5 minutes.
(2) About 1 cm of each end face of the thin plate was etched for 5 minutes.

  After the etching, as shown in FIG. 6, a protrusion P2 provided on the substrate 602 with the lower portions of the ends E2, E4 among the four ends E1, E2, E3, E4 of the thin plate on the substrate 602, Supported by P4, the other ends E1 and E3 were gradually lowered in the direction of the substrate, the load was increased until the thin plate broke, and the load when the thin plate broke was measured. The result is shown in FIG. In FIG. 7, the horizontal axis indicates the etching method, and the vertical axis indicates the load when the thin plate is broken.

  It can be seen from the figure that the strength is higher when the whole thin plate is etched for 5 minutes than before the etching. This is because the strength was improved because the damaged portion of the end face was removed by etching. It can also be seen that the strength is stronger when the end face (end face 5 mm) is etched for 5 minutes than when the whole thin plate is etched for 5 minutes. This is an effect of avoiding that the area without damage is thinned by etching and cracked by etching only the end face.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is a thin plate processing method and a thin plate processing apparatus for a semiconductor material such as silicon or a metal material, and a thin plate having high strength can be produced by etching, and is useful in the field of solar cells.

It is the schematic of the holding | maintenance container used for this invention. It is the schematic of the processing container and washing container used for this invention. It is the schematic which shows the rotational movement of the holding | maintenance container used for this invention. It is the schematic of the moving means used for this invention. It is the schematic of the manufacturing apparatus of the thin plate used for this invention. It is the schematic of the test method of the intensity | strength of a thin plate. It is a figure which shows the relationship between the etching method of a thin plate, and load resistance.

Explanation of symbols

  101 crucible, 102 raw material melt, 103 heating means, 104 base plate, 110 horizontal operation rail, 111 slide body, 112 lifting mechanism, 113 suspension column, 114 rotation mechanism, 115 rotation column, 116 pedestal column, 117 pedestal, 201 Thin plate, 202 processing container, 203 cleaning container, 203C bottom convex part, 204 processing solution, 205 cleaning liquid, 206 heater, 210 holding container, 210A hooking part, 211 lid, 220A holding bar.

Claims (5)

  A method for processing a thin plate having at least one of a metal material and a semiconductor material having a damaged portion near an end surface, wherein the damaged portion is removed by immersing the vicinity of the end surface of the thin plate in a processing solution .   The thin plate processing method according to claim 1, wherein the processing liquid is an etching liquid. A thin plate holding container capable of accommodating the thin plate so that its main surface is in a substantially vertical direction;
Means for moving the holding container capable of moving the holding container in a vertical direction and a horizontal direction by a predetermined distance;
A processing container in which the holding container is carried in and out by the moving means and contains a processing liquid;
The holding container is carried in and out after being processed in the processing container, and includes a cleaning container containing a cleaning liquid,
The processing container and the cleaning container have container rotating means capable of immersing the vicinity of the other end face of the thin plate in the processing liquid by rotating the holding container by a predetermined angle in conjunction with the moving means.
Thin plate processing equipment.   The thin plate processing apparatus according to claim 3, wherein the processing liquid is an etching liquid.   The thin plate processing apparatus according to claim 3, wherein the holding container includes a hooking portion that can engage with the moving means.

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