JP6406006B2 - Grooving tool and scribing device equipped with the groove machining tool - Google Patents

Description

The present invention relates to a grooving tool used when manufacturing an integrated thin film solar cell such as a compound system using a chalcopyrite compound, cadmium telluride, or the like, and a scribing apparatus to which the grooving tool is attached.
Here, the chalcopyrite compound includes CIGS (Cu (In, Ga) (Se, S) ₂ ), CIS (CuInS ₂ ) and the like in addition to CIGS (Cu (In, Ga) Se ₂ ).

  In a thin film solar cell using a compound semiconductor as a light absorption layer, an integrated structure in which a plurality of unit cells are connected in series on a substrate is generally used.

  A method for producing a conventional chalcopyrite compound integrated thin film solar cell will be described. FIG. 7 is a schematic diagram showing a manufacturing process of a CIGS thin film solar cell. First, as shown in FIG. 7A, a Mo electrode layer 22 to be a plus-side lower electrode is formed on an insulating substrate 21 made of soda lime glass (SLG) or the like by a sputtering method, and then the lower portion is formed by scribe processing. A groove P1 for electrode separation is formed.

  Thereafter, as shown in FIG. 7B, a light absorption layer 23 made of a compound semiconductor (CIGS) thin film is laminated on the Mo electrode layer 22, and a ZnS thin film for heterojunction is formed thereon. A buffer layer 24 is formed, and an insulating layer 25 made of a ZnO thin film is formed thereon. Then, an interelectrode contact groove P2 reaching the Mo electrode layer 22 is formed by scribing at a position spaced apart from the lower electrode separation groove P1 by a predetermined distance in the lateral direction.

  Subsequently, as shown in FIG. 7C, a transparent electrode layer 26 as an upper electrode made of a ZnO: AI thin film is formed on the insulating layer 25, and reaches the lower Mo electrode layer 22 by scribing. A groove P3 for electrode separation is formed.

  In the process of manufacturing the integrated thin film solar cell described above, a laser scribing method and a mechanical scribing method have been used as a technique for groove-growing the electrode separation grooves P2 and P3.

  In the laser scribing method, for example, as disclosed in Patent Document 1, a groove for electrode separation is formed by irradiating a laser beam emitted by exciting a Nd: YAG crystal with a continuous discharge lamp such as an arc lamp. However, the photoelectric conversion characteristics of the light absorption layer 23 may be deteriorated by the heat of the laser light during scribing.

  In addition, as disclosed in Patent Document 2 and Patent Document 3, for example, the mechanical scribing method moves the cutting edge of a groove processing tool having a tapered tip while pressing it against a substrate while applying a predetermined pressure. Is a technique for processing a groove for electrode separation. At present, this mechanical scribing method is often performed.

JP-A-11-31815 JP 2002-094089 A JP 2004-115356 A

Grooving tools used in the mechanical scribing method generally have a round sectional shape using a lathe that can be finished with high accuracy at a low cost. As a groove processing tool having such a circular cross section, the tip of the rod-shaped body 27 as shown in FIG. Patent Documents 2 and 3 disclose 29 edge portions as blade edges 30.
Further, in order to precisely finish the parallelism of the left and right side walls of the groove to be processed, a cylindrical portion 31 having a uniform upper and lower diameter is formed below the tapered portion 28 as shown in FIG. Some have the part 32 as a cutting edge. The horizontal bottom surface 29 at the tip of the tool is provided so as not to damage the Mo electrode layer by making the tip of the blade edge sharp when grooving.

While pressing this groove processing tool at a constant pressure so as not to leave the thin film solar cell substrate, the groove processing is performed by relatively moving along the scheduled scribe line. Since the tool bounces in response to the force in the vertical direction due to the inertial force, a constant pressing force, for example, a force of 0.5 N or more is required to suppress it.
However, when the cutting edge of the grooving tool is used while being pressed against the thin film solar cell with the above pressing force, the outer peripheral side surface and the bottom surface corresponding to the depth h of the grooving groove from the new state of FIG. The edge portions 30 and 32 of the blade edge are worn by contact with the film of the solar cell substrate, and as shown in FIG. 9B, the horizontal width of the blade edge is reduced and the sharpness is deteriorated. If the left and right widths of the tip of the blade tip are reduced, the width of the groove to be processed becomes narrow and the groove having the specified dimensions cannot be processed with high precision, and the electrode separation grooves P2 and P3 in FIG. It may also occur when the effect cannot be obtained. In addition, when the cutting edge sharpness deteriorates, not only can the grooves not be processed cleanly, but also some thin films may be irregularly peeled off and removed more than necessary, resulting in the characteristics and yield of solar cells. There was a problem that it decreased.

  Therefore, in view of the above-described problems, the present invention can improve wear resistance and extend the service life by adding a device to the cutting edge portion, and can suppress phenomena such as film peeling during grooving. It is an object of the present invention to provide a grooving tool and a scribe device to which the grooving tool is attached.

  The groove processing tool for a thin film solar cell of the present invention made to solve the above-mentioned problems is a groove processing tool for forming a groove by peeling a thin film of a thin film solar cell substrate, comprising a rod-shaped body, and the body A taper-shaped taper portion formed at the lower portion of the taper portion, and a tip portion of the tapered portion, or a blade tip region formed at a tip portion of a cylindrical portion formed continuously to the taper portion, the blade tip region is , Consisting of a horizontal bottom surface and a cutting edge formed at a corner of the bottom surface and the outer peripheral side surface of the cylindrical portion or the tapered portion, and the outer peripheral side surface is coated with a coating made of a hard material harder than a tool material In addition, the bottom surface of the tool material is exposed.

The grooving tool of the present invention is used by being attached to a holder of a scribe head incorporated in a scribe device. At the time of scribing, in the grooving tool according to the present invention, since the outer peripheral side surface is coated with a hard material harder than the tool material, the wear resistance of the outer peripheral side surface is improved, and the above-mentioned blade edge portion is worn and becomes thin. This is alleviated. In addition, this makes it possible to carry out highly accurate groove processing while keeping the groove width to be processed constant, and to extend the tool life.
Also, since the bottom surface of the tool material is left exposed, the wear rate of the hard coating formed on the outer peripheral surface and the wear of the bottom surface (tool material) that is lower than this coating The speed is balanced, and wear progresses almost evenly in a substantially horizontal posture. Thereby, there exists an effect that the sharp corner | angular part used as a blade edge is hold | maintained and deterioration of sharpness can be prevented.

In the present invention, the cutting edge region is formed at the tip portion of the tapered portion, and the central angle of the outer peripheral side surface of the tapered portion is formed within a range of 10 ° to 30 ° (centered at 20 °). It is good to do.
As a result, the vibration (impact) applied to the tool can be kept small as shown by the experimental value, and the parallelism of the left and right side wall surfaces of the groove to be machined can be maintained by reducing the central angle. The groove can be precisely processed. In addition, the left and right edges of the groove to be processed are not cut obliquely, and the occurrence of film peeling can be suppressed. Furthermore, although the taper portion has a small angle, the diameter increases from the bottom to the top, so that the strength can be increased compared to a regular cylindrical tool, and the occurrence of problems such as breaking during scribing is suppressed. be able to.

In the present invention, the taper portion is formed in a two-stage shape by an upper taper portion and a lower taper portion having a smaller central angle on the outer peripheral side surface than the upper taper portion, and a tip portion of the lower taper portion forms the cutting edge region. The central angle of the lower taper portion is formed within a range of 10 ° to 30 ° (centered at 20 °), and the height of the lower taper portion is the dimension of the groove depth to be processed. It is preferable to have a configuration that is larger and smaller than the diameter of the bottom surface.
As a result, vibration (impact) applied to the tool can be kept small, and the left and right edges of the groove to be machined can be prevented from being obliquely cut by reducing the central angle, thereby preventing film peeling. can do. Moreover, the lower taper portion is formed with a height (height) smaller than the bottom surface formed with a small diameter corresponding to the groove width to be processed, and the upper portion has an angle larger than that of the lower taper portion. Since the taper portion is continuously provided and reinforced, it is possible to eliminate troubles such as the lower taper portion being bent from the middle portion during scribing. In addition, since the height of the lower taper portion is formed with a dimension larger than the depth of the groove to be processed, a groove having a predetermined depth can be reliably processed.

The schematic front view which shows one Embodiment of the scribing apparatus using the groove processing tool of this invention. The whole perspective view and partial expanded sectional view which show the groove processing tool of this invention. The whole perspective view and partial expanded sectional view which show another Example of the groove processing tool of this invention. The table | surface which shows the vibration concerning a blade edge | tip and film | membrane peeling width when a 3000m groove | channel is machined using three types of tools from which a tip angle differs. The figure which shows three types of groove processing tools used for the experiment of FIG. The whole perspective view and partial expanded sectional view which show another Example of the groove processing tool which concerns on this invention. The schematic diagram which shows the manufacturing process of a general CIGS type thin film solar cell. The front view which shows the example of the conventional groove processing tool. Explanatory drawing which shows abrasion of the blade edge | tip of the conventional groove processing tool.

Hereinafter, details of the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a schematic front view showing an embodiment of an integrated thin film solar cell scribing apparatus using a groove processing tool according to the present invention.
The scribing apparatus A includes a table 1 on which the solar cell substrate W is placed and held. The table 1 can move in the Y direction (front-rear direction in FIG. 1) along a horizontal rail 2 and is driven by a screw shaft 3 that is rotated by a motor (not shown). Further, the table 1 can be rotated in a horizontal plane by a rotation driving unit 4 incorporating a motor.

A bridge 7 including support columns 5 and 5 on both sides provided on the table 1 and a beam (lateral beam) 6 extending horizontally in the X direction is provided so as to straddle the table 1.
The beam 6 is provided with a guide 9 extending horizontally in the X direction. A scribe head 10 is attached to the guide 9 so that the motor M can move in the X direction.

  A holder 11 that holds a groove processing tool 8 for scribing the thin film surface of the solar cell substrate W placed on the table 1 is provided below the scribe head 10. The holder 11 is formed so that it can be moved up and down together with the grooving tool 8 by the fluid cylinder 12.

FIG. 2 shows a grooving tool 8 according to the present invention, FIG. 2 (a) is a perspective view showing the overall shape, and FIG. 2 (b) is an enlarged sectional view of a cutting edge portion. The grooving tool 8 is made of a material having excellent tool characteristics such as steel and cemented carbide.
The grooving tool 8 includes a rod-shaped body 81 having a circular cross section that is substantially an attachment portion to the holder 11, a tapered tapered portion 82 formed integrally with the lower portion of the body 81, and a tapered portion 82. A thin cylindrical portion 83 formed of a regular cylindrical body integrally formed with a thinned tip portion, and a cutting edge region 84 formed at the tip portion of the cylindrical portion 83. The body 81, the taper portion 82, and the cylindrical portion 83 are preferably formed so that their respective axes are coaxial. Accordingly, the tapered portion 82 and the cylindrical portion 83 can be processed easily and accurately by gripping and rotating the body 81 with a chuck of a processing machine such as a lathe and grinding the tip portion of the body 81 with a cutting tool.

The cutting edge region 84 of the grooving tool 8 includes a horizontal bottom surface 85 of the cylindrical portion 83 and a cutting edge 87 formed at the corner between the bottom surface 85 and the outer peripheral side surface 86 of the cylindrical portion 83.
The outer peripheral side surface 86 of the cylindrical portion 83 is coated with a hard material film 88 harder than the tool material. The thickness of the film 88 is about 0.5 μm to 2 μm.
DLC (diamond-like carbon) is preferred as the hard material, but it is also effective with hard ceramics such as TiN (titanium nitride), TiC (titanium carbide), and TiCN (titanium nitride carbide), and is coated by CVD or PVD. can do.
The hard material to be coated is selected to be harder than the tool material. For example, DLC is used when the tool material is cemented carbide.

The coating 88 made of a hard material may be a partial peripheral surface including a portion that fits into a groove to be processed on the outer peripheral side surface 86, but may be coated over the entire outer peripheral side surface 86 or the outer peripheral side surface of the tapered portion 82. Absent. However, the bottom surface 85 is not coated and the background (the surface of the tool material) is left. In this case, for example, in the step of forming the DLC film by the plasma CVD method, when the tool is put in the vacuum chamber and the film is formed on the outer peripheral side surface 86, the unnecessary portion including the bottom surface 85 can be peeled off. It can be manufactured by closing with a film and peeling off this blocking film later.
It should be noted that instead of the above-described method of coating by closing a portion that does not require film formation with a peelable blocking film, the bottom surface 85 is coated together with the outer peripheral side surface 86, and then the coating on the bottom surface 85 is worn away and removed. It may be.

  When scribing using the groove processing tool 8 described above, the groove processing tool 8 is attached to the holder 11 of the scribing head 10 with the tool tip facing downward. Then, the table 1 is moved in the Y direction so that the scribe line of the solar cell substrate W is positioned directly below the grooving tool 8, and then the grooving tool 8 is moved downward and its tip is moved by the fluid cylinder 12. While being pressed against the surface of the solar cell substrate W, it is moved in the X direction to perform scribing in the X direction. Moreover, when performing the scribe process of the Y direction on the surface of the solar cell board | substrate W, the table 1 is rotated 90 degree | times and the operation | movement similar to the above is performed.

  At the time of the above scribe processing, in the groove processing tool 8 of the present embodiment, a part of the outer peripheral side surface 86 of the cylindrical portion 83 including at least a portion that fits into the groove of the solar cell substrate W is made of a hard material that is harder than the tool material. Since it is coated, the wear resistance of the outer peripheral side surface that is fitted into the groove of the solar cell substrate and receives a large resistance during scribing is improved. As a result, it is possible to relieve the above-mentioned cutting edge portion from being worn and thinned, to maintain a constant groove width to be processed, to perform highly accurate groove processing, and to extend the tool life. .

  Further, since the bottom surface 85 is left with the ground surface exposed, the wear rate of the coating film 88 having a high hardness formed on the outer peripheral side surface 86 and the bottom surface 85 (tool material) having a hardness lower than that of the coating film 88. The wear speed is balanced, and the wear rate is evenly worn in a substantially horizontal posture. Thereby, the shape change of the corner | angular part used as the blade edge | tip 87 can be suppressed, a sharp state can be hold | maintained over a period longer than before, and deterioration of sharpness can be prevented.

FIG. 3 shows another embodiment of the present invention. FIG. 3 (a) is an overall perspective view, and FIG. 3 (b) is an enlarged cross-sectional view of a blade edge portion. In this embodiment, a cutting edge region 84 is provided directly at the tip of a tapered tapered portion 82 formed at the lower portion of the body 81. Further, the coating 88 formed of a hard material coating is formed on the outer peripheral side surface in the vicinity of the blade edge region 84 of the tapered portion 82.
The central angle α of the outer peripheral side surface 86 of the tapered portion 82 is set in a range of 10 ° to 30 ° centered on 20 ° from data of the following experiment by the inventors.

FIG. 4 shows the vibrations applied to the tool when the inventors of the present invention processed 3000 m of a groove on a solar cell substrate using three types of grooving tools made of cemented carbide having different blade angles, and film separation of the processed groove. It is a table | surface which shows the result of having verified the width | variety. In the table, the angle in the tool type column indicates the central angle α of the outer peripheral conical surface (outer peripheral side surface) of the three types of tools used in the experiment. FIG. 5 shows the grooving tool used in the above-mentioned experiment. FIG. 5 (b) shows a center angle α of 20 °, and FIG. 5 (c) shows a 45 ° tool. FIG. 5 (a) shows the case where the corners forming the cutting edge are formed at right angles, and the central angle α is 0 ° here.
From these experiments, it can be seen that the film with a central angle of 20 ° has a film peeling width as small as about half that of the film with a large angle of 45 °. Further, it was found that the displacement amount (vibration) of the load applied to the tip of the blade edge is smaller at the center angle of 20 ° than the others, and the impact on the tool is small.
It has been found that if the central angle α of the outer peripheral conical surface is in a range of ± 10 ° centered on 20 °, the film peeling width can be suppressed to substantially the same level.
Therefore, in this embodiment, the central angle α of the tapered portion is set to 10 ° to 30 ° with 20 ° as the center.
In this embodiment, the vibration (impact) applied to the tool can be suppressed as shown by experimental values, and the parallelism of the left and right side wall surfaces of the groove to be machined can be maintained by reducing the central angle α. It is possible to precisely machine clean grooves. In addition, the left and right edges of the groove to be processed are not cut obliquely, and the occurrence of film peeling can be suppressed. Further, since the taper portion 82 has a small angle but increases in diameter from the bottom to the upper side, the strength can be increased as compared with a conventional regular cylindrical body tool, and the occurrence of problems such as breaking during scribing can be avoided. Can be suppressed.

FIG. 6 shows still another embodiment of the grooving tool according to the present invention. FIG. 6 (a) is an overall perspective view, and FIG. 6 (b) is an enlarged cross-sectional view of the cutting edge portion.
In this embodiment, the rod-shaped body 81 is formed in a two-stage shape with a taper portion 82 having a large central angle α and a lower taper portion 82b having a smaller angle than the upper taper portion 82a, and a tip portion of the lower taper portion 82b. The blade edge region 84 is formed at the top. A coating 88 made of a hard material is formed on the outer peripheral side surface from the lower taper portion 82b to the upper taper portion 82a by coating. The central angle α1 of the lower taper portion 82b is formed within a range of 10 ° to 30 ° centered on 20 °, which is a preferable numerical value in the experimental data of FIG. 4, and the central angle α2 of the upper taper portion 82a is 140 °. It is formed at the above large angle. Further, the height H of the lower taper portion 82b is larger than the dimension of the groove depth to be processed and smaller than the diameter D of the bottom surface 85.

  In the two-step groove processing tool 8, in addition to the improvement of wear resistance by coating with a hard material, the central angle α1 of the lower taper portion 82b is set to 10 ° to 30 ° centering on 20 °. Therefore, as indicated by the above experimental values, vibration (impact) applied to the tool can be suppressed to a low level. Further, by reducing the central angle α1, the left and right edges of the groove to be processed are not obliquely cut and the occurrence of film peeling can be suppressed. Furthermore, the lower taper portion 82b is formed with a height (height) smaller than the bottom surface 85 formed with a small diameter corresponding to the groove width to be processed, and its upper portion is larger than the lower taper portion 82b. Since the upper taper portion 82a having an angle is connected and reinforced, the lower taper portion 82b is not broken from the middle portion during scribing. Further, since the height H of the lower taper portion 82b is formed with a dimension larger than the depth of the groove to be processed, a groove having a predetermined depth can be processed reliably.

  As described above, the representative embodiments of the present invention have been described. However, the present invention is not necessarily limited to the above-described embodiment structures, and can be appropriately modified within the scope of achieving the object and without departing from the scope of the claims. It is possible to change.

  The present invention can be applied to a groove processing tool that can be used for manufacturing an integrated thin film solar cell using a compound semiconductor film such as a chalcopyrite compound or cadmium telluride.

A scribe device W solar cell substrate P1, P2, P3 scribe groove 8 groove processing tool 81 body 82 taper part 82a upper taper part 82b lower taper part 83 cylindrical part 84 cutting edge area 85 bottom face 86 outer peripheral side 87 cutting edge 88 coating 10 scribe head 11 holder

Claims (5)

A groove processing tool for forming a groove by peeling a thin film of a thin film solar cell substrate,
A rod-shaped body, a tapered tapered portion formed at the lower portion of the body, a tip portion of the tapered portion, or a cutting edge region formed at a tip portion of a cylindrical portion formed continuously to the tapered portion; With
The cutting edge region is composed of a horizontal bottom surface, and a cutting edge formed at a corner portion of the bottom surface and the outer peripheral side surface of the cylindrical portion or the tapered portion,
The outer peripheral side surface is coated with a coating made of a hard material harder than the tool material, and the bottom surface is a grooving tool in which the background of the tool material is exposed.   The grooving tool according to claim 1, wherein the cutting edge region is formed at a tip portion of the tapered portion, and a central angle of an outer peripheral side surface of the tapered portion is formed within a range of 10 ° to 30 °. The taper portion is formed in a two-stage shape by an upper taper portion and a lower taper portion having a smaller central angle of the outer peripheral side surface than the upper taper portion, and a tip portion of the lower taper portion forms the cutting edge region,
The central angle of the lower taper portion is formed within a range of 10 ° to 30 °, and the height of the lower taper portion is larger than the dimension of the groove depth to be processed and smaller than the diameter of the bottom surface. The grooving tool according to claim 1.   The grooving tool according to any one of claims 1 to 3, wherein a material of the grooving tool is a cemented carbide and the coating is DLC.   A scribe head that holds the groove processing tool according to any one of claims 1 to 4 via a holder and a table on which the thin film solar cell substrate is placed, and the scribe head is attached to the thin film solar cell substrate. The scribing apparatus is configured to process the groove on the surface of the thin-film solar cell substrate with the cutting edge of the groove processing tool by relatively moving the groove.

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