KR20120101460A - Method and device for ablation of thin-films from a substrate - Google Patents

Abstract

The present invention relates to a method of ablating materials (3, 4, 5) from a substrate (2) with a laser, wherein the laser spot of the laser with respect to the surface of the substrate (2) in two distinct directions relative to the substrate (2). And means for guiding a, comprising the steps of: a) moving (13) the substrate (2) with respect to the laser spot; And b) moving the laser spot on the surface of the substrate 2 in a closed loop pattern by impinging the pointing means with sinusoidal harmonic vibrations in each of the two distinct directions. It is about a method.

Description

METHOD AND DEVICE FOR ABLATION OF THIN-FILMS FROM A SUBSTRATE}

The present invention relates to a method and apparatus for ablation of material from a substrate with a laser. In particular, the present invention has a thin film solar system having a first electrode layer, a semiconductor layer and a second electrode layer stacked on a substrate, whereby a so-called layer-stack is divided into a plurality of thin film solar cells electrically connected in series. A method and apparatus for manufacturing an optical module are provided. More specifically, the present invention relates to a method and apparatus for locally removing a layer-stack positioned around a thin film solar module by a laser beam.

Generally, thin film photovoltaic cells comprise amorphous and / or microcrystalline silicon films having pin or nip junction structures arranged parallel to the thin film surface. The pin / nip structure is sandwiched between electrode layers, which are transparent membrane electrodes that extend continuously into each of a plurality of regions on one main surface of the substrate, such as, for example, a translucent substrate, often referred to as a superstrate.

Since the coating process used for thin film solar cells generally affects the entire substrate, suitable electrical insulation to the frame or housing of the final thin film solar cell module is required. There is also a need to protect photovoltaic active cells from environmental influences such as moisture and / or oxygen. Thus, it is known in the art to encapsulate a photovoltaic active layer by, for example, laminating the substrate in an additional cover such as a back glass that bonds or laminates the foil between the substrate and the cover. Since the edge region of the substrate, the so-called peripheral region, is the contact surface for the aforementioned environmental influences, it is clear that special surroundings should be inclined to the peripheral region.

Thus, layer-stacks comprising electrode layers and semiconductor layers, also called active layers, are often removed in narrow strips parallel to the edges, ie in the peripheral region. In order to perform this ablation, the prior art teaches using sand-blasting, but this has the adverse effect of not completely removing the active layer in the surrounding area and / or damaging the underlying substrate. This results in a much greater risk of moisture and oxygen, which in turn negatively affects the use of thin film solar modules.

It is an object of the present invention to provide an improved process for removing unwanted material from the edge region of a substrate.

This object is achieved by the independent claims. Advantageous embodiments are listed in the dependent claims.

In particular, the object is a method of ablating a material from a substrate with a laser, comprising: indicating means for guiding a laser spot of the laser with respect to the substrate surface in two distinct directions,

a) moving the substrate with respect to the laser spot; And

b) moving the laser spot on the substrate surface in a closed loop pattern by impinging the indicating means with sinusoidal harmonic vibrations in each of two distinct directions.

It is achieved by a material ablation method comprising a.

Thus, removing the material by moving the laser spot on the substrate surface in a closed loop pattern is an idea of the present invention, whereby material can be removed from the substrate in a very uniform and reliable manner. Since the pointing means collide with harmonic oscillations of the sinusoidal type which are preferably superimposed in two distinct directions, the laser spot provided by the processing laser beam is most preferably moved constantly over the substrate surface, thus Only removing the material does not cause any damage to the substrate due to the unwanted density of the laser per unit surface area of the substrate that is larger than necessary.

Lasers have optical pulse processing, such as Nd: YAG or Yt: YAG, for wavelengths of 1064 and 1030 nm, with pulse durations shorter than 100 ns and pulse energy densities ranging from 0.1 J / cm ² to 20 J / cm ^2. It can be provided as any laser known to those skilled in the art, such as a laser resonator for generating a beam.

In another embodiment, the laser and / or pointing means comprise an image member for projecting rectangular, flexible and / or circular fiber cable output onto the substrate surface to be processed. The substrate is any known to those skilled in the art to which the invention pertains to the laser spot, for example by means of positioning means provided as a belt or by a roll, preferably in a straight direction. Can be moved in a way.

Thus, in contrast to the prior art, guiding laser spots in a closed loop pattern using sinusoidal harmonic vibrations is not desired from any substrate without negatively affecting the substrate in any kind. It is based on the discovery that it provides much more efficient ablation of the material. When the substrate is provided in a thin film solar cell, the method according to the invention is particularly advantageous because it provides for obtaining good electrical insulation due to the uniform removal of all materials of the semiconductor layer and the electrode layer of the solar module. Ablating the material by moving the laser spot as a closed loop pattern over the substrate in accordance with the solution of the present invention is such that the laser spot is preferably constantly moved over the substrate, and thus, for example, the direction of movement as known from the prior art. The thermal degradation of the substrate is much less because the substrate is not damaged when the laser movement is stopped to perform the inversion of.

In general, the indicating means for guiding the laser spot can be provided as any means known from the prior art. However, according to a preferred embodiment of the present invention, the indicating means comprises a scanner optics having two pivotable mirrors which guide the laser spot in two distinct directions. Preferably, the scanner optics comprises a galvo scanner with a head mirror that provides guidance for the laser spot in two distinct directions. More preferably, the scanner optics move the laser spot in the plane of the substrate surface. In another embodiment, the scanner optics comprise three or more mirrors. These embodiments allow a very simple and inexpensive production of the indicating means according to the invention. In addition, these embodiments allow a very precise method of guiding the laser spot in a closed loop pattern on the substrate surface while being impacted by sinusoidal harmonic vibrations.

The pattern can include any pattern known from the prior art to guide the laser spot on the substrate surface in a closed loop pattern. However, according to another preferred embodiment of the present invention, the present invention,

c) pivoting the mirror at the same frequency and oscillating phase shift of 0 °, 90 ° or 180 °; or

d) pivoting the mirror at different frequencies and oscillating phase shifts greater than 0 °

.

Such embodiments preferably use a galvo scanner head, preferably having two or more mirrors, to superimpose harmonic oscillations onto the substrate surface, for example, a closure with circles, lines and / or rasage figures. Provide a loop pattern. In order to provide a circle, the pivoting frequencies of both mirrors are preferably the same and the phase shift between the vibrations of the two scanner heads is 90 °. The line can be realized by vibrating both mirrors with a phase shift of 0 ° or 180 ° between the same frequency and the vibrations of the two scanner heads. The rasage figure can be implemented at a different frequency, for example between different phase shifters of 10 °, 40 ° and / or 80 ° and the vibrations of the two scanner heads. This scanning pattern is particularly advantageous because the high vibration frequency provides reliable ablation of the material and much less degradation of the substrate. It is thereby evident to one of ordinary skill in the art that each closed loop pattern may be an open loop pattern when considering turning on and off the laser at the beginning and end of the ablation process. .

It has been found that the harmonic oscillations of the scanner mirrors enable the high oscillation frequencies of the mirrors, and thus the scanning strategy based on the continuous movement of the scanning pattern on the substrate surface to be processed has been found to be the most efficient for removing material from the substrate. Due to the overlap of the movement of its own circular scanning pattern along the edge and the desired circular movement of the laser spot, it is found in various tests without negatively affecting the substrate from the viewpoint of thermal stress and / or load resulting from the laser spot. As can be seen, as the laser spot is moved preferably and consistently over the substrate, an increased effect of laser processing on the area near the edge can be obtained.

In general, two distinct directions may be provided as any distinct direction relative to the substrate surface. According to a preferred embodiment of the invention, the two distinct directions are perpendicular to each other and extend orthogonally parallel to the edges and / or boundaries of the substrate, respectively. Thus, preferably, the mirror of the indicating means guides the laser spots orthogonal to each other in parallel to the edge of the substrate, thus allowing ablation of the material from the whole of the substrate surface.

In another preferred embodiment, the method comprises repeating step b). Therefore, step b) is preferably carried out at least twice. This dual scanning strategy, in which each substrate surface is treated twice by at least two independent, eg consecutive, laser ablation events, is most successful in removing all material from the substrate. In another example, step b) is repeated more than 2 times, for example 3 times, 4 times or 4 times. Also, since treating the substrate surface with a circular scanning pattern has been found to be most efficient for removing all material, this dual or more scanning strategy is performed by the circular scanning pattern.

In another preferred embodiment, the substrate is provided in a thin film solar cell, the material comprises a first electrode layer, a photoelectric conversion layer and a second electrode layer, and the material is provided on the substrate such that the second electrode layer is provided as a surface to be treated by the laser spot. Are attached in the order mentioned.

Basic build ups of conventional thin film solar cells or thin film solar modules are known to those skilled in the art. Such thin film solar cells generally comprise a substrate, for example a glass substrate, on which a transparent or translucent electrode layer is attached, a pin or nip structure (n = negatively doped silicon, i = intrinsic silicon, a photoelectric conversion semiconductor formed of an amorphous and / or microcrystalline silicon film representing p = positively doped silicon), followed by a back electrode layer. The back electrode layer may again comprise a transparent conductive layer and a reflective layer, a conductive and reflective metal layer or technical equivalents. The photoelectric conversion semiconductor may consist of a single, double or a plurality of junctions, each junction again exhibiting a pin or nip structure.

The substrate may be any substrate suitable for making thin film devices known to those skilled in the art. In a preferred embodiment, the substrate is float glass, security glass or quartz glass. Preferably the larger sized float glass generally used in the manufacture of solar cells is produced by transporting molten glass in an extended tin bath in the forming chamber, preferably continuously. The molten glass is then spread over the tin surface and / or drawn by suitable means in at least one direction as a flat, continuous glass sheet or layer. By carefully controlling the cooling and pulling processes, the shape as well as the thickness of the glass sheet can be adjusted as a result. Preferably, the substrate is provided as an essentially flat substrate.

The layers according to the invention can be attached by various attachment techniques known to those skilled in the art. In a preferred embodiment of the present invention, the thin film layer is deposited by chemical vapor depostion (CVD) or physical vapor deposition (PVD), such as a vacuum sputtering process. More preferably, the vapor deposition process is a plasma enhanced CVD (PECVD), an atmospheric pressure CVD (APCVD) and / or a metal-organic CVD (MOCVD) deposition process. Most preferably, the deposition process is low pressure CVD (LPCVD).

In another preferred embodiment of the invention, the substrate surface is divided into an inner region and a peripheral region surrounding the inner region, and instead of step b) b ') each of two distinct directions, a sinusoidal type harmonic oscillation Impinging the directing means, thereby moving the laser spot only on the surface of the peripheral region of the substrate in a closed loop pattern.

Thus, for the case where the substrate is provided in the thin film solar cell, the substrate of each thin film solar cell is preferably in accordance with the present invention according to step b ') and an inner region having an electrode layer and a photoelectric conversion layer attached onto the substrate. It includes a peripheral area that is predicted to be ablated by the method according to the method, which is also called an internal active area. Thus, after performing step b ′), the substrate of each thin film solar cell is free of material and preferably only a substrate by ablation of an internal active region having an electrode layer and a photoelectric conversion layer attached thereon and a laser spot. It includes a peripheral passive region containing only bays. In another embodiment, the interior region is arranged adjacent to the peripheral region.

For the case where the substrate surface in the passive region according to step b ') is collided in a closed loop pattern in the form of a circle according to the preferred embodiment as described above, the density of laser shots per unit area is found to be highest at the edge of the peripheral region. lost. Preferably, since one edge is the outer edge of the substrate to be machined, and the other edge is the boundary between the module inner region and the peripheral region, the scanning pattern in the form of a circle provides a safe removal and internal removal of all materials attached near the outer substrate edge. It is particularly beneficial to ensure smooth boundaries of the area.

It has been found that the results using the circular scanning pattern can be obtained even near the edge of the substrate. Thus, this embodiment is beneficial for the safe and precise removal of material in the peripheral area of the substrate, providing good protection of the peripheral area against environmental influences such as humidity and oxygen. Most preferably, the laser spot is moved parallel to the edges and / or boundaries of the substrate such that the laser spot is moved so that the material is preferably completely ablated along the edges and / or boundaries of the substrate, for example along the surrounding area. While constantly moving the laser spot in the direction, the laser spot performs a scanning pattern of circles.

In another embodiment of the present invention, the maximum width of the closed loop pattern on the substrate surface is preferably equal to or less than the width of the peripheral region provided between the inner region and the edge of the substrate. Thus, it is particularly desirable for the entire width of the peripheral area to be impacted by the closed loop pattern of the laser spot in the peripheral area in one "move" of the laser spot over the substrate.

It is an object of the present invention to provide a support for a substrate to be processed, a laser resonator to provide a processed laser beam, an optical system disposed in the path of a processed laser beam that projects the laser processed beam as a laser spot on a substrate surface to be disposed on the support. And a scanner optic for moving the laser spot within the plane of the substrate surface and a locator for moving the substrate relative to the processing beam, the scanner optic having a sine wave in each of two directions forming a closed loop pattern on the substrate surface. It is further obtained by a laser processing system that moves the laser spot in two distinct directions using harmonic vibrations of the type.

Such laser processing systems provide an advantageous solution for ablating material, for example, from a substrate by means of a laser spot in which harmonics are oscillated as a closed loop pattern onto the substrate surface, resulting in very precise and reliable ablation of unwanted materials. Allow.

Preferably, the laser resonator produces an optical pulsed processing beam having a pulse duration of less than 100 ms and a pulse energy density in the range of 0.1 J / cm ² to 20 J / cm ² . In another embodiment, the optical system includes a projection member that mechanically projects a square shape around the fiber cable onto the substrate surface. The support and / or positioner may be provided as any means known in the art to which the present invention pertains and supports the substrate, respectively. Preferably, the laser processing system is suitable for carrying out the method as described above.

In another preferred embodiment, the scanner optics comprise two pivotable mirrors that guide the laser spot in two distinct directions. In this regard, it is preferred that the pivotable mirror pivots the mirror at the same frequency and oscillating phase shift of 0 °, 90 ° or 180 °, or pivots the mirror at different frequencies and oscillation phase shifts greater than 0 °. .

In another embodiment, the laser spot has a relative velocity with respect to the substrate of 7 m / s to 10 m / s, preferably 1 m / s to 4 m / s, most preferably 100 mm / s to 400 mm / s. And / or the substrate is moved relative to the processing laser beam at a speed of 100 mm / s to 400 mm / s by the positioner.

The substrate may be provided in a thin film solar cell, the thin film solar cell may include a material to be processed by a processing laser beam, the material may include a first electrode layer, a photoelectric conversion layer, and a second electrode layer, and the material may be The second electrode layer may be attached on the substrate in the order mentioned in order to serve as the substrate surface.

In another embodiment, the substrate is divided into an interior region and a peripheral region surrounding the interior region, and the scanner optics generate sinusoidal vibrations in each of two directions to create a closed loop pattern only on the peripheral region of the substrate surface. Move the laser spot in two distinct directions.

The object of the invention is also solved by the use of the laser processing system according to the invention for micromachining, surface heat treatment, laser induced surface modification and / or surface hardening of the substrate. It has been found that the laser processing system according to the invention is also applicable to other technical fields in which the layered area has to be laser abbreviated from the base substrate. Such applications may include micromachining, surface heat treatment, laser induced surface modification of materials, surface hardening, and the like.

One of ordinary skill in the art will adjust or modify the features of the present invention, such as laser power or wavelength, to achieve this object without departing from the scope of the present invention.

Other advantages and / or embodiments of the laser processing system and / or laser processing system are those of ordinary skill in the art to which the present invention pertains from a method for ablating a material according to the present invention as described herein. Will be derived by the ruler.

These and other aspects of the invention will be apparent from the embodiments described below, and will be illustrated with reference to the embodiments described below.
In the drawing:
1 shows a cross section of a thin film solar cell according to the prior art,
2 shows a top view of a conventional thin film solar cell according to the prior art,
3 shows a preferred embodiment of the present invention in a top view.

1 shows a schematic cross section of a conventional thin film solar cell 1 according to the prior art.

On the transparent insulating substrate 2, the transparent front electrode layer 3 is arranged. The photoelectric conversion semiconductor 4 is formed on the transparent front electrode layer 3, and an additional transparent rear electrode layer 5 is formed on the photoelectric conversion semiconductor 4. The transparent electrode layers 3 and 5, also called transparent cconductive oxide (TCO), may comprise SnO ₂ , Indiumtinoxide (ITO) or ZnO, the latter being preferably produced by low pressure CVD (LPCVD) .

The photoelectric conversion semiconductor 4 comprises an amorphous and / or microcrystalline silicon film stack that can be laser doped and manufactured by CVD, preferably PECVD, to obtain photovoltaic properties, as is known in the art. do.

1 further shows grooves 6, 7 and 8. The purpose of this structure is to construct a photovoltaic module 1 consisting of a plurality of solar cells electrically connected in series. Thus, the transparent electrode layer 3 is divided by a first isolation groove 6 which determines the width of the cell. When the entire layer stack is built in the order of layer (3) -groove (6) -layer (4) -groove (7) -layer (5) -groove (8) during manufacturing, the photoelectric conversion semiconductor layer (4) Fills the groove.

Grooves 7 filled with material from the transparent back electrode layer 5 allow for electrical contact between adjacent cells. In fact, the back electrode of one cell contacts the front electrode of an adjacent cell. The back surface electrode layer 5 and the photoelectric conversion semiconductor 4 are finally divided by the third isolation groove 8. This structuring process is preferably obtained by using a laser light or the like.

In a further process step, the electrical contacts are generally attached to the thin film solar cell and a back reflecting layer and encapsulation means are provided, for example by laminating the protective layer and the substrate.

FIG. 2 is a top view of the thin film solar cell 1 as described in FIG. 1. Cells connected in series build up an electric potential for the environment. Thus, there is a need for suitable electrical isolation for the cell environment, which can lead to thin film layer stacks 3, 4, 5 formed on a substrate, for example thin film stacks 3, 4, 5 having active semiconductor based thin film photovoltaic regions. ) And the inner region 9 by separating it into a peripheral region 10.

3 shows the peripheral region 10 and the inner region 9, which are located along the edge of the module 1 and have a general width 11 between 12.8 mm and 15 mm. Depending on the individual specifications, a width 11 between 5 mm and 20 mm can be realized.

A laser is used to remove the layer stacks 3, 4, 5 of the thin film solar module 1 in the peripheral region 10. Such a laser system includes a laser resonator for generating an optical pulsed processing beam having a pulse duration less than 100 ns and a pulse energy density in the range of 0.1 J / cm ² to 20 J / cm ² .

The projection member projects a square or circular fiber cable output on the surface of the solar module 1 to be processed. Since the area of the image of the fiber cable on the surface called laser spot below is substantially smaller than the peripheral area, the laser spot is moved by the scanner optics in the peripheral area 10 on the module 1 surface. . Scanner optics can be realized, for example, with a movable mirror. The mirror is pivoted as needed or by moving the projection member in the xy direction while providing laser light through the flexible fiber.

In order to obtain good electrical insulation, uniform removal of essentially all of the material 3, 4, 5 of the semiconductor 4 and the electrode layers 3, 5 of the solar module 1 is required. Here, the scanning pattern 12 plays a significant role: According to the invention, the scanning pattern 12 describing the movement of the laser spot with respect to the substrate 2 is in two distinct directions, namely the It is built by a sine wave type harmonic oscillation of the galvo scanner head in two directions perpendicular to and parallel to the corresponding edge. Two harmonic vibrations of the two mirrors of the galvo scanner header are superimposed on the surface to be machined, so that the following various scanning patterns 12 can be realized:

Circle with phase shift between the same pivoting frequency with both mirrors and vibration of two headers, 90 ° Line with phase shift between the pivoting frequency with both mirrors and vibration of two headers of 0 ° or 180 ° Or Lissajous-figure resulting from different frequencies between different phase shifts and vibrations of the two heads.

In particular, circles are most preferred for the following reasons:

1) The density of laser spots per unit surface area is highest at the edge of the peripheral region 10. As also shown in FIG. 3, one of the edges is the outer edge of the substrate 2 to be processed and the other is the boundary between the module inner region 9 and the peripheral region 10.

Thus, the circular scanning pattern 12 ensures the safe removal of all the materials 3, 4, 5 attached near the edges of the outer substrate 2 and the smooth boundary to the inner region 9. This is true even when some materials 3, 4, 5 are accidentally attached on the surface of the substrate 2 opposite the surface supporting the photovoltaic layer stacks 3, 4, 5, near the edge of the substrate 2. Valid.

2) Harmonic oscillations of the scanner mirrors enable high oscillation frequencies of the mirrors, thus enabling a scanning strategy based on the continuous movement of the scanning pattern 12 on the surface to be machined. Overlap of the circular movement of the laser spot with the movement of the circular scanning pattern itself along the edge results in an increased effect of laser processing on the area near the edge.

3) The dual scanning strategy in which the entire peripheral region 10 is processed by two independent, for example, successive laser ablation events is the semiconductor layer 4 and the electrode layers 3, 5 of the thin film solar module 1. Has been found to be most successful in removing all materials from This double scan strategy is most efficiently obtained by the circular scanning pattern.

The removal of material from the edge region of the substrate 2 allows to limit the active thin film stack formed on the substrate 2 as the inner region 9 from the periphery. This separation can be achieved, for example, by removing the semiconductor layer 4 and the electrode layers 3, 5 in the peripheral region 10 of the thin film coated substrate 2 by sand blasting or using a laser.

In a laser processing system for carrying out the method according to the invention, an Nd: YAG or Yt: YAG type laser resonator can be used which provides light with wavelengths of 1064 and 1030 nm, respectively. Preferably, the laser has a pulse duration shorter than 100 ns and a pulse energy density in the range of 0.1 J / m ² to 20 J / cm ² . The optical system disposed in the path of the machining beam has an optical projection member for projecting the output of a square or circular fiber cable and the optical fiber cable on the surface of the solar module 1 to be processed. Scanner optics allow for moving the laser spot within the plane of the surface to be machined. The relative scanning speed of the scanner optics is preferably chosen between 7 m / s and 20 m / s on the surface to be machined and the positioner moves the module at a relative traveling speed between 100 mm / s and 400 mm / s. Let's do it. Such a laser processing system may further comprise a support for the substrate 2 to be processed.

The preferred scanning strategy of the laser spot on the surface to be activated is a circle having a diameter equal to or substantially the same as the width 11 of the peripheral region 10 of the module. Another path for a laser spot, such as a Lissajous figure, is formed by overlapping two harmonic vibrations of the mirror of the galvo scanner optics that are part of the laser processing system, spanning the width 11 of the peripheral region 10, and the laser spot. Moves on a circle or other Lissajous figure with a relative tangential velocity between 7 m / s and 20 m / s, and the circle or other Lissajous figure is to be machined at a relative speed of 100 mm / s to 400 mm / s. Moving along the edge of (1) and the latter is obtained by moving the substrate 2 by the positioner at a speed of 100 mm / s to 400 mm / s as compared to the mechanical optical system.

Although the invention has been illustrated and described in the drawings and detailed description for carrying out the foregoing invention. Such examples and descriptions are illustrative or not limiting; The invention is not limited to the disclosed embodiments.

Other variations to the disclosed embodiments can be understood and carried out by those of ordinary skill in the art from studying the drawings, the disclosure and the appended drawings in practicing the claimed invention. In the claims, the phrase "comprising" does not exclude other components or steps, and the singular description does not exclude a plurality. The simple fact that certain criteria are mentioned in mutually different dependent claims does not indicate that a combination of these criteria cannot be used to advantage. Any reference signs in the claims should not be considered as limiting the scope.

1 thin film solar cell
2 boards
3 first electrode layer
4 photoelectric conversion layer
5 second electrode layer
6 groove
7 groove
8 groove
9 internal zones
10 surrounding areas
11 width
12 scanning patterns
13 moves

Claims (15)

In the method of ablating the materials 3, 4, 5 from the substrate 2 with a laser,
And indicating means for guiding a laser spot of the laser with respect to the surface of the substrate 2 in two distinct directions,
a) moving (13) the substrate (2) with respect to the laser spot; And
b) in each of said two distinct directions, moving said laser spot on said substrate 2 surface in a closed loop pattern by impinging said indicating means with sinusoidal harmonic vibrations;
/ RTI >
Material ablation method.
The method of claim 1,
Said indicating means comprises scanner optics having two pivotable mirrors for guiding said laser spots in said two distinct directions,
Material ablation method.
The method according to claim 1 or 2,
c) pivoting the mirror at the same frequency and oscillating phase shift of 0 °, 90 ° or 180 °; or
d) pivoting the mirror at different frequencies and oscillating phase shifts greater than 0 °
/ RTI >
Material ablation method.
4. The method according to any one of claims 1 to 3,
The two distinct directions are perpendicular to each other and extend orthogonal to each other parallel to the edge of the substrate,
Material ablation method.
5. The method according to any one of claims 1 to 4,
Repeating step b) above;
Material ablation method.
The method according to any one of claims 1 to 5,
The substrate 2 is provided in the thin film solar cell 1, the material 3, 4, 5 comprises a first electrode layer 3, a photoelectric conversion layer 4 and a second electrode layer 5, The materials 3, 4, 5 are attached on the substrate 2 in the order mentioned so that the second electrode layer 5 is provided as a surface of the substrate 2.
Material ablation method.
7. The method according to any one of claims 1 to 6,
The substrate 2 surface is divided into an inner region 9 and a peripheral region 10 surrounding the inner region 9,
Instead of step b) above,
b ') in each of said two distinct directions, impinging said indicating means with a harmonic oscillation of the sinusoidal type, causing said laser spot only on the surface of said peripheral region 10 of said substrate 2 in a closed loop pattern; Including moving,
Material ablation method.
The method of claim 7, wherein
The maximum width of the closed loop pattern 12 on the substrate 2 is equal to or less than the width of the peripheral region 10 provided between the inner region 10 and an edge of the substrate 2,
Material ablation method.
A support for the substrate 2 to be processed;
A laser resonator providing a processed laser beam;
An optical system disposed in the path of the processed laser beam that projects the laser processed beam as a laser spot on the surface of the substrate to be disposed on the support;
Scanner optics for moving the laser spot within the plane of the substrate (2) surface; And
Positioner for moving the substrate relative to the processing laser beam
Including,
The scanner optics moves the laser spot in two distinct directions using sinusoidal harmonic vibrations in each of two distinct directions forming a closed loop pattern on the substrate surface.
Laser processing system.
10. The method of claim 9,
The scanner optics comprising two pivotable mirrors guiding the laser spot in the two distinct directions,
Laser processing system.
The method of claim 10,
The pivotable mirror pivots the mirror at the same frequency and oscillating phase shift of 0 °, 90 ° or 180 °, or pivots the mirror at a different frequency and oscillation phase shift greater than 0 °,
Laser processing system.
The method according to any one of claims 9 to 11,
The laser spot has a relative velocity with respect to the substrate 2 of 7 m / s to 10 m / s, preferably 1 m / s to 4 m / s, most preferably 100 mm / s to 400 mm / s. And the substrate 2 is moved relative to the processing laser beam at a speed of 100 mm / s to 400 mm / s by the positioner,
Laser processing system.
The method according to any one of claims 9 to 12,
The substrate 2 is provided in a thin film solar cell 1, wherein the thin film solar cell 1 comprises materials 3, 4, 5 to be processed by the processing laser beam, and the material 3, 4. 5 includes a first electrode layer 3, a photoelectric conversion layer 4, and a second electrode layer 5, wherein the materials 3, 4, and 5 are formed by the second electrode layer 5 being the substrate 2. Attached on the substrate 2 in order to be provided as a surface)
Laser processing system.
The method according to any one of claims 9 to 13,
The substrate 2 is divided into an inner region 9 and a peripheral region 10 surrounding the inner region 9,
The scanner optics moves the laser spot in the two distinct directions with sinusoidal harmonic oscillations in each of two directions to create a closed loop pattern only on the peripheral region 10 of the surface of the substrate 2. Photography,
Laser processing system.
Use of a laser treatment system according to any of claims 9 to 14 for micromachining, surface heat treatment, laser induced surface modification and / or surface hardening of the substrate (2).

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