JP2009202170A - Laser beam machining apparatus and reflection mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To process a body to be processed in space-saving manner at a low cost for a short time even when processing the body using laser beam having a predetermined wavelength and laser beam having a wave length different from the predetermined wavelength. <P>SOLUTION: The laser beam machining apparatus machines the body 60 to be processed by irradiating laser beams I, S thereon. The laser beam machining apparatus is provided with a laser oscillator 1 for oscillating the laser beam I having the predetermined wavelength, a wavelength conversion element 5 which converts a part of the laser beam I having the predetermined wavelength to the laser beam S having the different wavelength, a reflection mirror 10 which reflects the laser beams I, S which passes through the wavelength conversion element 5, and a converging part 7 which converges the laser beams I, S on the body 60 to be processed. One surface of the reflection mirror 10 selectably reflects the laser beam I having the predetermined wavelength and the other surface different from the one surface of the reflection mirror 10 selectably reflects the laser beam S which has the different wavelength from the predetermined wavelength through conversion by the wavelength conversion element 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus that processes a workpiece using laser light having a predetermined wavelength and laser light having a wavelength different from the predetermined wavelength, and a reflection mirror used in the laser processing apparatus.

  When each layer is selectively laser processed for a thin film device having a multilayer structure, processing is performed using laser light having a wavelength suitable for each purpose. At this time, a laser having a necessary wavelength is prepared for each process. For example, in a normal process for producing a thin-film silicon solar cell, the flow is generally as shown in FIG.

  First, the transparent conductor 62 is formed on the glass substrate 61 (see FIG. 15A). Next, the transparent conductor 62 on the glass substrate 61 is removed (TCO scribe) by laser light (IR light) I having a wavelength near 1064 nm (see FIG. 15B).

  Next, a Si layer 65 is formed on the transparent conductor 62 (see FIG. 15C). Next, the Si layer 65 on the transparent conductor 62 is removed (Si scribe) by laser light (SHG light) S having a wavelength near 532 nm (see FIG. 15D).

  Next, a metal layer 66 is formed on the Si layer 65 (see FIG. 15E). Next, the metal layer 66 on the Si layer 65 is removed together with the Si layer 65 (metal scribe) by laser light (SHG light) S having a wavelength near 532 nm (see FIG. 15F). Thereafter, the transparent conductor 62, the Si layer 65, and the metal layer 66 are removed by IR light I (separation scribe) (see FIG. 15G), and the object 60 is manufactured. In addition, in FIG.15 (g), the to-be-processed object 60 is rotated 90 degrees from the position shown in FIG.15 (f).

  In this separation scribe, the IR light I is absorbed by the transparent conductor 62, so that the transparent conductor 62 is peeled off so as to burst from the glass substrate 61, and at the same time, the Si layer 65 and the metal layer immediately above (directly under processing). This is done by removing 66 as well.

  At this time, the transparent conductor 62 is melted and re-solidified, and the components adhere to the Si layer 65 and the metal layer 66, so that the Si layer 65 and the metal layer 66 are altered. Due to such alteration, the resistance value from the metal layer 66 to the transparent conductor 62 film is lowered, and the performance of the completed device is lowered. Therefore, in order to ensure the quality in the separated and scribed portion, it is necessary to remove the altered portions of the Si layer 65 and the metal layer 66.

  If the SHG light S is used, the Si layer 65 and the metal layer 66 are selectively removed while leaving the transparent conductor 62 due to the difference in the absorptance of the laser light, so that this altered portion can be removed (see FIG. 16 (a) (b)). That is, after the IR light I is irradiated (see FIG. 15G), the SHG light S may be irradiated (see FIG. 16A), and the conventional laser processing apparatus that oscillates the IR light I and the SHG light S Two laser processing devices that oscillate the laser were used.

  However, using two laser processing devices, such as a laser processing device that oscillates the IR light I and a laser processing device that oscillates the SHG light S, increases the cost, and the two laser processing devices A large space is required for placement. Usually, these laser processings are performed by relative movement of the laser processing apparatus and the object to be processed, but in this case, since the process is performed twice, processing time is required. In addition, it is impossible for layout or arrangement to arrange two laser processing devices that irradiate IR light and two laser processing devices that irradiate SHG light, and to irradiate two laser beams of IR light and SHG light at the very close. is there.

  Further, as a method for realizing such a plurality of wavelengths of light with a single laser oscillator, the output of a single laser oscillator is divided and the divided laser light is passed through a wavelength converter ( For example, see JP-A-7-263726.

  However, the laser light after wavelength conversion is inevitably mixed with light of the original wavelength, so that the selectivity is poor and processing failure may occur. It is also difficult to align the two split beams.

  The present invention has been made in consideration of such points, and includes laser light having a predetermined wavelength (for example, IR light) and laser light having a wavelength different from the predetermined wavelength (for example, SHG light). Even if it is used to process the object to be processed, the laser processing apparatus can process the object at a low cost, save space, and can be adjusted in a short time, making adjustment and maintenance (such as optical axis alignment) simple. And it aims at providing the reflective mirror used for the said laser processing apparatus.

The laser processing apparatus according to the present invention comprises:
In a laser processing apparatus that processes a target object by irradiating a laser beam,
A laser oscillator that oscillates laser light having a predetermined wavelength;
A wavelength conversion element that converts part of laser light having a predetermined wavelength oscillated from the laser oscillator into laser light having a different wavelength;
A reflection mirror that reflects the laser light that has passed through the wavelength conversion element;
A condensing unit that condenses the laser beam on the object to be processed,
Either one of the front surface and the back surface of the reflection mirror selectively reflects the laser beam having the predetermined wavelength,
The other surface opposite to the one surface of the reflection mirror selectively reflects the laser beam converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength.

  With such a configuration, the object to be processed is processed using laser light having a predetermined wavelength (for example, IR light) and laser light having a wavelength different from the predetermined wavelength (for example, SHG light). However, the object to be processed can be processed in a low cost, in a space-saving manner, and in a short time, and adjustment and maintenance (such as alignment of the optical axis) are simplified.

In the laser processing apparatus according to the present invention,
The condensing part is preferably disposed between the wavelength conversion element and the reflection mirror.

  With such a configuration, a laser beam having a predetermined wavelength and a laser beam having a wavelength different from the predetermined wavelength can be irradiated at different positions on the object with different beam spot diameters. For this reason, a to-be-processed object can be processed efficiently.

In the laser processing apparatus according to the present invention,
The condensing unit includes a first condensing unit and a second condensing unit, and the laser light reflected by the front surface of the reflecting mirror is collected on the object to be processed by the first condensing unit,
It is preferable that the laser beam reflected by the back surface of the reflection mirror is condensed on the object to be processed by the second light collecting unit.

  With such a configuration, a laser beam having a predetermined wavelength and a laser beam having a wavelength different from the predetermined wavelength can be irradiated at different positions on the object with different beam spot diameters. For this reason, a to-be-processed object can be processed efficiently.

In the laser processing apparatus according to the present invention,
The reflection mirror preferably has a portion having a different thickness.

In such an aspect, it further comprises incident position changing means for changing the incident position of the laser beam on the reflection mirror,
It is preferable that the optical path difference between the laser light reflected by the front surface of the reflection mirror and the laser light reflected by the back surface of the reflection mirror can be adjusted.

  In such an aspect, it is more preferable that the incident position changing unit moves the reflection mirror along the in-plane direction of the reflection mirror.

  With such a configuration, the size of the laser spot of the laser light irradiated onto the object to be processed can be adjusted as appropriate.

In the laser processing apparatus according to the present invention,
One area of the front surface of the reflecting mirror selectively reflects the laser beam having the predetermined wavelength,
The other region of the front surface of the reflection mirror selectively reflects the laser light converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength,
A region corresponding to one region of the front surface of the back surface of the reflection mirror selectively reflects the laser light converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength,
Of the back surface of the reflecting mirror, the region corresponding to the other region of the front surface selectively reflects the laser beam having the predetermined wavelength,
It is preferable that the incident position of the laser beam on the reflection mirror can be changed.

  With such a configuration, the laser processing apparatus can be used in a mode in which scanning is performed in two directions.

In such an aspect, the apparatus further includes a moving mechanism that moves at least the reflection mirror and the light collecting unit relative to the object to be processed.
It is preferable that the incident position of the laser beam on the reflection mirror is changed according to the moving direction of the moving mechanism, and the wavelength of the laser beam irradiated on the object to be processed is changed.

The reflecting mirror according to the present invention is
One surface selectively reflects laser light having a predetermined wavelength,
The other surface facing the one surface selectively reflects laser light having a wavelength different from the predetermined wavelength.

In the reflection mirror according to the present invention,
One area of one surface selectively reflects the laser beam having the predetermined wavelength,
The other region of the surface selectively reflects laser light having a wavelength different from the predetermined wavelength,
A region corresponding to one region of the one surface of the other surface selectively reflects laser light having a wavelength different from the predetermined wavelength,
It is preferable that a region of the other surface corresponding to the other region of the one surface selectively reflects the laser beam having the predetermined wavelength.

  According to the present invention, either one of the front surface and the back surface of the reflection mirror selectively reflects laser light having a predetermined wavelength, and the other surface facing the one surface of the reflection mirror is wavelength-converted. The laser beam converted by the element and having a wavelength different from the predetermined wavelength is selectively reflected. For this reason, even when processing an object to be processed using laser light having a predetermined wavelength (for example, IR light) and laser light having a wavelength different from the predetermined wavelength (for example, SHG light), The object to be processed can be processed in a short time with a reduced cost and space.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment Hereinafter, a first embodiment of a laser processing apparatus according to the present invention will be described with reference to the drawings. Here, FIG. 1 thru | or FIG. 4 (a) (b) is a figure which shows the 1st Embodiment of this invention.

  The laser processing apparatus according to the present embodiment processes an object 60 by irradiating laser light I, S (see FIGS. 1 and 2). In addition, as this to-be-processed object 60, the thin film silicon solar cell which is a multilayer thin film device can be used. The object 60 includes a glass substrate 61, a transparent conductor 62 disposed on the glass substrate 61, an Si layer 65 disposed on the transparent conductor 62, and a metal layer disposed on the Si layer 65. 66 (see FIGS. 3A to 3C and FIGS. 15A to 15G). In the following description, the object 60 is used as the object to be processed, but this is only an example. The laser processing apparatus according to the present invention can be used for continuous processing and all types of processing using light of a plurality of wavelengths.

  As shown in FIG. 1, the laser processing apparatus includes a laser oscillator 1 that oscillates a laser beam I having a predetermined wavelength, and a part of the laser beam I that is oscillated from the laser oscillator 1 and has a predetermined wavelength. The wavelength conversion element 5 that converts the laser light S having different wavelengths, the reflection mirror 10 that reflects the laser light I and S that has passed through the wavelength conversion element 5, and the wavelength conversion element 5 and the reflection mirror 10 are disposed. And a condensing unit 7 such as a lens for condensing the laser beams I and S on the object 60 to be processed.

  In the present embodiment, the laser beam I having a wavelength of about 1064 nm is used as the laser beam I having a predetermined wavelength, and the wavelength of about 532 nm, which is half of 1064 nm, is used as the laser beam S having a different wavelength. This will be described below using the laser beam S. In the following description, the laser light I having a wavelength near 1064 nm is also expressed as IR light I, and the laser light S having a wavelength near 532 nm is also expressed as SHG light S.

  In addition, the wavelength conversion element 5 shown in FIG. 1 uses a part (approximately half) of the IR light I having a wavelength near 1064 nm oscillated from the laser oscillator 1 as SHG light having a wavelength near 532 nm, which is half of 1064 nm. S is converted to S.

  Further, as shown in FIG. 1, the front surface 10 a of the reflection mirror 10 is configured to selectively reflect the IR light I having a wavelength of around 1064 nm, and the back surface 10 b of the reflection mirror 10 is formed by the wavelength conversion element 5. The SHG light S that has been converted and has a wavelength in the vicinity of 532 nm, which is half of 1064 nm, is selectively reflected. In the present application, the “front surface 10a of the reflection mirror 10” means the surface of the reflection mirror 10 on the laser oscillator 1 side, and the “rear surface 10b of the reflection mirror 10” means the surface of the reflection mirror 10 on the laser oscillator 1 side. Means the opposite surface (surface facing the front surface 10a).

  By the way, in FIG. 1, the condensing part 7 is arrange | positioned so that it may focus with respect to IR light I among the lights which reach the to-be-processed object 60 (refer FIG. 2).

  Next, the operation of the present embodiment having such a configuration will be described.

  First, IR light I is oscillated from the laser oscillator 1 (see FIG. 1).

  Next, the laser light I passes through the wavelength conversion element 5 (see FIG. 1). At this time, a part (about half) of the IR light I oscillated from the laser oscillator 1 is converted into the SHG light S (see FIG. 1). That is, about half of the laser beams I and S that have passed through the wavelength conversion element 5 are made of IR light I, and the remaining half is made of SHG light S.

  Next, the laser beams I and S that have passed through the wavelength conversion element 5 reach the reflection mirror 10 through the condenser 7. Then, the IR light I is reflected on the front surface 10 a of the reflection mirror 10. On the other hand, the SHG light S is reflected on the back surface 10b of the condensing / reflecting mirror 10 (see FIG. 1).

  The IR light I and the SHG light S reflected by the reflection mirror 10 in this manner remove the separation scribe of the object 60 and a part of the Si layer 65 and the metal layer 66 that have been altered by the separation scribe. (See FIGS. 3A to 3C and FIG. 15G).

  That is, first, the layer of the transparent conductor 62, the Si layer 65, and the metal layer 66 in the object 60 is removed by the IR light I (separation scribe) (FIGS. 3A and 15G). reference). More specifically, when the IR light I is absorbed by the transparent conductor 62, the transparent conductor 62 is peeled off so as to burst from the glass substrate 61, and at this time, the Si layer 65 directly above (directly below during processing). The metal layer 66 is also removed.

  At this time, the transparent conductor 62 is melted and re-solidified, and the components adhere to the Si layer 65 and the metal layer 66, whereby the Si layer 65 and the metal layer 66 are altered (see the hatched portion in FIG. 3A). ).

  Next, portions of the Si layer 65 and the metal layer 66 disposed on the transparent conductor 62 that have been altered by the SHG light S are removed (see FIGS. 3B and 3C). At this time, the SHG light S passes through the transparent conductor 62 and is selectively absorbed by the Si layer 65 due to the difference in absorption rate. For this reason, the Si layer 65 and the metal layer 66 can be selectively removed.

  Moreover, since the condensing part 7 is arrange | positioned so that it may focus with respect to IR light I among the lights which reached the to-be-processed object 60, as shown in FIG.2 and FIG.3 (a) (b). Furthermore, the diameter of the beam spot Sa of the SHG light S is larger than the diameter of the beam spot Ia of the IR light I. As a result, portions of the Si layer 65 and the metal layer 66 disposed on the transparent conductor 62 that have been altered by the IR light I can be efficiently removed.

  In addition, as shown in FIG. 1, the beam spot Ia of the IR light I and the beam spot Sa of the SHG light S are arranged by arranging the condensing unit 7 between the wavelength conversion element 5 and the reflection mirror 10. It is possible to irradiate different positions on the target object 60 without irradiating the same position on the target object 60.

  Further, the optical path difference between the IR light I and the SHG light S can be changed by changing the thickness of the reflection mirror 10. For example, when the condensing unit 7 is arranged so that the IR light I reflected by the front surface 10 a of the reflection mirror 10 is focused on the object 60, the focal point of the SHG light S reflected by the back surface 10 b of the reflection mirror 10. As a result, the diameter of the beam spot Sa of the SHG light S on the object to be processed 60 becomes larger than the diameter of the beam spot Ia, and the irradiation position is also shifted. As a result, the processing with the IR light I and the processing with the SHG light S can be performed on the workpiece 60 in different locations (which are very close to each other).

  Further, when processing is performed by relatively moving the laser processing apparatus and the target object 60, the processing can be performed with a slight time difference (processing can be performed almost simultaneously). Furthermore, since the processing region by the SHG light S can be widened, the altered portion of the workpiece 60 can be removed.

  As described above, according to the present embodiment, the IR light I is selectively reflected by the front surface 10a and the SHG light S is selectively reflected by the rear surface 10b by using only one reflection mirror 10. can do. For this reason, the transparent conductor 62 is processed with the IR light I and the altered Si layer 65 and the metal layer 66 are removed by the IR light I with a single laser processing apparatus that is the same size as the conventional laser processing apparatus. can do. For this reason, compared with the case where two laser processing apparatuses are arrange | positioned, while being able to reduce the space required for arrangement | positioning, it can prepare at low cost.

  In addition, since the object to be processed 60 is processed using the laser beams I and S reflected by the single reflecting mirror 10, the IR light I and the SHG light S are irradiated on the object to be processed 60 at close positions. can do. For this reason, the to-be-processed object 60 can be processed in a short time. The distance between the IR light I and the SHG light S on the object 60 and the spot diameter of the SHG light S can be adjusted as appropriate by adjusting the thickness of the reflection mirror 10 (FIG. 4 (a) (b)).

  Furthermore, in the case of moving the laser processing apparatus while fixing the object to be processed 60, a unit having one reflection mirror 10 (a unit including the laser oscillator 1, the wavelength changing element 5, the reflection mirror 10, and the light collecting unit 7 ( Note that this unit may include only the reflecting mirror 10 and the condensing unit 7)), and the spot of the laser beams I and S can be moved only by moving, so that the operation control of the laser processing apparatus can be performed. It can be simplified.

  By the way, in the above, the front surface 10a of the reflection mirror 10 selectively reflects the laser light I having a predetermined wavelength (a wavelength in the vicinity of 1064 nm), and the back surface 10b of the reflection mirror 10 is converted by the wavelength conversion element 5 to have a predetermined wavelength. Although the description has been made using the mode in which the laser beam S that has a wavelength different from the wavelength (near 532 nm) is selectively reflected, the present invention is not limited to this, and the back surface 10b of the reflection mirror 10 has a predetermined wavelength (near 1064 nm). The laser beam I having a wavelength different from the predetermined wavelength (near 532 nm) is selected by selectively reflecting the laser beam I having a wavelength of) and the front surface 10a of the reflection mirror 10 is converted by the wavelength conversion element 5. May be reflected.

Second Embodiment Next, the second embodiment of the present invention will be described with reference to FIG. In the second embodiment shown in FIG. 5, instead of the condensing unit 7 being disposed between the wavelength conversion element 5 and the reflection mirror 10, the first collection is performed between the reflection mirror 10 and the workpiece 60. The condensing part 7 which consists of the optical part 7a and the 2nd condensing part 7b is arrange | positioned. The IR light I reflected by the front surface 10a of the reflection mirror 10 is collected on the object 60 by the first light collecting unit 7a, and the SHG light S reflected by the back surface 10b of the reflection mirror 10 is The light is condensed on the object to be processed 60 by the two light collecting portions 7b. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 4A and 4B.

  In the second embodiment shown in FIG. 5, the same parts as those in the first embodiment shown in FIGS. 1 to 4A and 4B are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, as shown in FIG. 5, the light collecting unit 7 including the first light collecting unit 7 a and the second light collecting unit 7 b is disposed between the reflection mirror 10 and the object 60 to be processed. Yes.

  Here, in order to efficiently remove the portion of the Si layer 65 and the metal layer 66 arranged on the transparent conductor 62 that has deteriorated when the transparent conductor 62 is processed by the IR light I, On the workpiece 60, the diameter of the beam spot Sa of the SHG light S needs to be larger than the diameter of the beam spot Ia of the IR light I (see FIGS. 2 and 3A and 3B). ).

  Therefore, in the present embodiment, the first light collecting portion 7a for condensing the laser light I reflected by the front surface 10a of the reflecting mirror 10 and the laser light S reflected by the back surface 10b of the reflecting mirror 10 are used. And a second light condensing part 7b for condensing light (see FIG. 5).

  Also in this embodiment, the same effects as those of the first embodiment can be obtained, and the following effects can be obtained as main effects.

  That is, the transparent conductor 62 is processed by the IR light I and the altered Si layer 65 and the metal layer 66 are removed by the IR light I with a single laser processing apparatus that is the same size as the conventional laser processing apparatus. be able to. For this reason, compared with the case where two laser processing apparatuses are arrange | positioned, while being able to reduce the space required for arrangement | positioning, it can prepare at low cost. In addition, since the object to be processed 60 is processed using the laser beams I and S reflected by the single reflecting mirror 10, the IR light I and the SHG light S are irradiated on the object to be processed 60 at close positions. The object 60 can be processed in a short time. Furthermore, in the case of moving the laser processing apparatus while fixing the object to be processed 60, a unit having one reflection mirror 10 (a unit including the laser oscillator 1, the wavelength changing element 5, the reflection mirror 10, and the light collecting unit 7 ( As described above, this unit may include only the reflecting mirror 10 and the condensing part 7)), and the spot of the laser beams I and S can be moved only by moving the laser processing apparatus. Operation control can be facilitated.

  By the way, the 1st condensing part 7a and the 2nd condensing part 7b are united, for example like a toroidal lens and a micro lens array, if a focal distance can set an irradiation place suitably by a light incident place. May be.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIGS. 6 to 11A and 11B. In the third embodiment shown in FIGS. 6 to 11 (a) and 11 (b), the light collecting unit 7 is disposed between the reflection mirror 10 and the object 60 to be processed. Further, the cross section of the reflection mirror 10 has a substantially wedge shape instead of a rectangular shape, and the reflection mirror 10 has portions having different thicknesses. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 4A and 4B.

  In the third embodiment shown in FIGS. 6 to 11A and 11B, the same reference numerals are given to the same parts as those in the first embodiment shown in FIGS. 1 to 4A and 4B. Detailed description will be omitted.

  In the present embodiment, due to the difference in thickness of the reflection mirror 10, the optical path difference between the IR light I and the SHG light S can be generated while appropriately adjusting depending on the incident location. The diameters and irradiation positions of the S beam spots Ia and Sa can be adjusted as appropriate.

  Also in this embodiment, the same effects as those of the first embodiment can be obtained, and the following effects can be obtained as main effects.

  That is, the transparent conductor 62 is processed by the IR light I and the altered Si layer 65 and the metal layer 66 are removed by the IR light I with a single laser processing apparatus that is the same size as the conventional laser processing apparatus. be able to. For this reason, compared with the case where two laser processing apparatuses are arrange | positioned, while being able to reduce the space required for arrangement | positioning, it can prepare at low cost. In addition, since the object to be processed 60 is processed using the laser beams I and S reflected by the single reflecting mirror 10, the IR light I and the SHG light S are irradiated on the object to be processed 60 at close positions. The object 60 can be processed in a short time. Furthermore, in the case of moving the laser processing apparatus while fixing the object to be processed 60, a unit having one reflection mirror 10 (a unit including the laser oscillator 1, the wavelength changing element 5, the reflection mirror 10, and the light collecting unit 7 ( As described above, this unit may include only the reflecting mirror 10 and the condensing part 7)), and the spot of the laser beams I and S can be moved only by moving the laser processing apparatus. Operation control can be facilitated.

  The reflecting mirror 10 can be moved along the front surface 10a direction by the incident position changing means (so that the optical path distance of the SHG light S reflected on the back surface 10b of the reflecting mirror 10 is changed). (See the double arrow in FIG. 7).

  Since the reflection mirror 10 is movable along the direction of the front surface 10a, the incident location is changed. Therefore, due to the difference in thickness of the reflection mirror 10, the optical path of the SHG light S reflected on the back surface 10b of the reflection mirror 10 is changed. Can be changed. Accordingly, the size of the laser spot of the SHG light S irradiated on the object 60 can be adjusted as appropriate, and the position of the laser spot of the SHG light S relative to the laser spot of the IR light I can be adjusted as appropriate. (See FIGS. 8A and 8B). By doing in this way, the adjustment for laser processing becomes easy.

  Further, instead of allowing the reflecting mirror 10 to move along the direction of the front surface 10a as described above, the condensing unit 7 or the entire optical axis including the condensing unit 7 can be moved. The incident position of the laser beams I and S on the reflection mirror 10 may be adjusted by adjusting the relative position with respect to the reflection mirror 10.

  Instead of selectively reflecting the IR light I on the front surface 10a of the reflecting mirror 10 and selectively reflecting the SHG light S on the back surface 10b of the reflecting mirror 10, the IR light I is selected on the back surface 10b of the reflecting mirror 10. The SHG light S may be selectively reflected by the front surface 10 a of the reflection mirror 10. In this way, the size of the laser spot of the IR light I irradiated onto the object 60 can be adjusted as appropriate, and the position of the laser spot of the IR light I relative to the laser spot of the SHG light S can be adjusted. It can be adjusted as appropriate.

  In the above description, the aspect in which the cross section of the reflection mirror 10 has a substantially wedge shape has been described. However, the shape is not particularly limited as long as the reflection mirror 10 has portions having different thicknesses. For example, the cross-section of the reflecting mirror 10 has a triangular shape, a staircase shape (see FIGS. 9A and 9B), a combination of a rectangular shape and a wedge shape (see FIG. 10A), and a curved surface with gradually increasing thickness. It may consist of an alternative shape (see FIGS. 10B and 11A and 11B).

  Here, as shown in FIGS. 10 (b) and 11 (a) (b), when the cross section of the reflecting mirror 10 is a curved surface and gradually changes in thickness, the reflecting surface becomes a convex mirror, and the focal point You can change the distance. For this reason, various spot diameters can be set according to the combination with the thickness (optical path difference) of the reflecting mirror 10.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIGS. 12 (a), 12 (b) to 14 (a), (b). In the fourth embodiment shown in FIGS. 12A, 12B to 14A, 14B, one region of the front surface 10a of the reflection mirror 10 selectively reflects the IR light I, and the front surface 10a The other region selectively reflects the SHG light S, and the region corresponding to one region of the front surface 10a (opposite region) among the back surface 10b of the reflection mirror 10 selectively reflects the SHG light S. Of the back surface 10b, the region corresponding to the other region of the front surface 10a (opposite region) selectively reflects the IR light I. The reflecting mirror 10 is movable along the in-plane direction. Other configurations are substantially the same as those of the first embodiment shown in FIGS. 1 to 4A and 4B.

  In the third embodiment shown in FIGS. 12A, 12B, 14A, and 14B, the same portions as those in the first embodiment shown in FIGS. 1 to 4A and 4B are used. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, the IR light I is selectively reflected by the front surface 10a of the reflection mirror 10 and the SHG light S is selectively reflected by the back surface 10b according to the incident positions of the laser beams I and S to the reflection mirror 10. (Refer to FIG. 12A), when the SHG light S is selectively reflected by the front surface 10a of the reflecting mirror 10 and the IR light I is selectively reflected by the rear surface 10b (see FIG. 12B), Can be appropriately selected.

  For this reason, either the case where the laser processing apparatus is used in the mode of scanning in the direction of the arrow in FIG. 12A, the case where the laser processing apparatus is used in the mode of scanning in the direction of the arrow in FIG. In this case, since the IR light I can be irradiated onto the object 60 before the SHG light S, the Si layer 65 and the metal layer 66 in which the SHG light S has been altered by the IR light I can be removed. .

  Also in this embodiment, the same effects as those of the first embodiment can be obtained. Further, as a main effect, the reciprocating operation of the relative movement between the laser processing apparatus and the object to be processed is performed with a simple mechanism. Either can be processed, and the processing efficiency can be increased.

  By the way, also in this Embodiment, the reflective mirror 10 whose cross section has a substantially wedge shape can be used. As described above, when the reflection mirror 10 having portions having different thicknesses is used so that the cross section has a substantially wedge shape, the reflection mirror 10 is simply moved along the in-plane direction (reflection mirror). 10), the laser beam I, S reflected on the back surface 10b of the reflecting mirror 10 is irradiated onto the object 60 to be processed. The size of the laser spot can be adjusted as appropriate, and the laser beam I reflected on the back surface 10b of the reflection mirror 10 with respect to the laser spot of the laser beams I and S reflected on the front surface 10a of the reflection mirror 10 is reflected. , S can be adjusted as appropriate.

  Note that, as in this embodiment, the laser processing apparatus is scanned in the direction of the arrow in FIG. 12A and the laser processing apparatus is scanned in the direction of the arrow in FIG. It is necessary to adjust the focal point of the spot with respect to the processing body 60 (see FIGS. 13A and 13B).

  That is, when the laser processing apparatus is scanned in the direction of the arrow in FIG. 12A, adjustment is performed so that the IR light I located on the left side of FIG. 12 (a) is adjusted so that the spot diameter of the SHG light S located on the right side is larger than the spot diameter of the IR light I located on the left side), and the laser processing apparatus is moved in the direction of the arrow in FIG. In the case of scanning, adjustment is performed so that the IR light I located on the right side of FIG. 12B is focused on the object 60 (IR light whose spot diameter of the SHG light S located on the left side is located on the right side). Need to be adjusted to be larger than the spot diameter of I).

Note that performing such adjustment, (see arrow A ₁ in FIG. 13 (b)) or by moving the condensing unit 7 in the optical axis direction, and the object 60, reflecting mirror 10 and the condensing section 7 the relative vertical position may be adjusted or (arrow a ₂ in FIG. 13 (b)) with. In addition, when using the reflection mirror 10 having portions having different thicknesses, the focal point may be adjusted by appropriately adjusting the incident positions of the laser beams I and S with respect to the reflection mirror 10.

Further, as shown in FIGS. 14A and 14B, when the cross section of the reflecting mirror 10 is a curved surface with a gradually changing thickness, the focal length of the IR light I or the SHG light S is set. can be changed (see arrow _{a 3} in FIG. 14 (b)). For this reason, depending on the combination with the thickness (optical path difference) of the reflection mirror 10, each of the case where the laser processing apparatus is scanned in the direction of the arrow in FIG. 12A and the case where the laser processing apparatus is scanned in the direction of the arrow in FIG. The IR light I may be adjusted on the object 60 to be focused. At this time, may be combined in the optical axis direction movement of the condensing unit 7 (see double arrow A ₄ in FIG. 14 (b)).

  By the way, although it demonstrated using the aspect which moves the reflective mirror 10 along the surface direction in the above, it is not restricted to this, You may move a laser processing apparatus with respect to the reflective mirror 10, The reflection mirror 10 may be reversed with respect to the light collecting unit 7.

  In each of the above embodiments, the IR light I having a wavelength near 1064 nm and the SHG light S having a wavelength near 532 nm have been described. However, the length of the wavelength is limited to these 1064 nm and 532 nm. It is not a thing. For example, instead of the SHG light S having a wavelength near 532 nm, a 355 nm laser beam (THG) having a wavelength of 1/3 of 1064 nm, a 266 nm laser beam (FHG) having a wavelength of 1/4 of 1064 nm, etc. The wavelength of the laser light emitted from the laser oscillator 1 may not be in the vicinity of 1064 nm in the first place. Moreover, what is necessary is just to select suitably the combination of the wavelength required for the target process.

  As described above, according to each embodiment described above, processing in the case where each thin film of a thin film device formed by stacking thin films of different materials, such as a thin film silicon solar cell, is selectively laser processed. Removal of altered parts of the surface and continuous processing of different wavelengths can be performed at low cost, space saving, and in a short time, and adjustment and maintenance (such as alignment of the optical axis) are also simplified.

1 is a schematic configuration diagram showing a laser processing apparatus according to a first embodiment of the present invention. The perspective view which showed the aspect which processes a to-be-processed object using the laser processing apparatus by the 1st Embodiment of this invention. The schematic cross-sectional view which showed the aspect which processes a to-be-processed object using the laser processing apparatus by the 1st Embodiment of this invention. The schematic longitudinal cross-sectional view which showed the aspect which processes a to-be-processed object using the laser processing apparatus by the 1st Embodiment of this invention. The schematic block diagram which shows the laser processing apparatus by the 2nd Embodiment of this invention. The schematic block diagram which shows the laser processing apparatus by the 3rd Embodiment of this invention. The schematic block diagram which shows the laser processing apparatus by another aspect of the 3rd Embodiment of this invention. The schematic longitudinal cross-sectional view which showed the aspect which processes a to-be-processed object using the laser processing apparatus by the 3rd Embodiment of this invention. The schematic longitudinal cross-sectional view which showed the aspect which processes a to-be-processed object using another aspect of the laser processing apparatus by the 3rd Embodiment of this invention. The schematic longitudinal cross-sectional view which showed another aspect of the reflective mirror used for the laser processing apparatus by the 3rd Embodiment of this invention. The schematic longitudinal cross-sectional view which showed the aspect which processes a to-be-processed object using the further another aspect of the laser processing apparatus by the 3rd Embodiment of this invention. The schematic block diagram which shows the laser processing apparatus by the 4th Embodiment of this invention. The schematic longitudinal cross-sectional view which showed the aspect which matches the focus of IR light on a to-be-processed object, in the laser processing apparatus by the 4th Embodiment of this invention. In the laser processing apparatus by the 4th Embodiment of this invention, the schematic longitudinal cross-sectional view which showed another aspect which matches the focus of IR light on a to-be-processed object. The schematic sectional drawing which showed the procedure which processes the thin film device of a multilayer structure. The schematic sectional drawing which showed the method of removing the part which changed quality among multilayer structures.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 5 Wavelength conversion element 7 Condensing part 7a 1st condensing part 7b Second condensing part 10 Reflective mirror 10a The front surface 10b of a reflective mirror 60 The back surface of a reflective mirror 60 To-be-processed object I IR light (laser light)
Ia IR light beam spot S SHG light (laser light)
Sa SHG beam spot

Claims (10)

In a laser processing apparatus that processes a target object by irradiating a laser beam,
A laser oscillator that oscillates laser light having a predetermined wavelength;
A wavelength conversion element for converting a part of laser light having a predetermined wavelength oscillated from the laser oscillator into laser light having a different wavelength;
A reflection mirror that reflects the laser light that has passed through the wavelength conversion element;
A condensing unit that condenses the laser beam on the object to be processed,
Either one of the front surface and the back surface of the reflecting mirror selectively reflects the laser beam having the predetermined wavelength,
The laser processing apparatus, wherein the other surface facing the one surface of the reflection mirror selectively reflects the laser beam converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength.   The laser processing apparatus according to claim 1, wherein the condensing unit is disposed between the wavelength conversion element and the reflection mirror. The condensing unit includes a first condensing unit and a second condensing unit, and the laser light reflected by the front surface of the reflecting mirror is collected on the object to be processed by the first condensing unit,
2. The laser processing apparatus according to claim 1, wherein the laser beam reflected by the back surface of the reflection mirror is collected on the object to be processed by the second light collecting unit.   The laser processing apparatus according to claim 1, wherein the reflection mirror has portions having different thicknesses. Incident position changing means for changing the incident position of the laser beam with respect to the reflection mirror,
The laser processing apparatus according to claim 4, wherein an optical path difference between the laser light reflected by the front surface of the reflection mirror and the laser light reflected by the back surface of the reflection mirror can be adjusted.   6. The laser processing apparatus according to claim 5, wherein the incident position changing unit moves the reflection mirror along an in-plane direction of the reflection mirror. One area of the front surface of the reflecting mirror selectively reflects the laser beam having the predetermined wavelength,
The other region of the front surface of the reflection mirror selectively reflects the laser light converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength,
A region corresponding to one region of the front surface of the back surface of the reflection mirror selectively reflects the laser light converted by the wavelength conversion element and having a wavelength different from the predetermined wavelength,
Of the back surface of the reflecting mirror, the region corresponding to the other region of the front surface selectively reflects the laser beam having the predetermined wavelength,
The laser processing apparatus according to claim 1, wherein an incident position of the laser beam on the reflection mirror can be changed. A moving mechanism for moving at least the reflecting mirror and the light collecting unit relative to the object to be processed;
The laser processing according to claim 7, wherein an incident position of the laser beam on the reflection mirror is changed depending on a moving direction of the moving mechanism, and a wavelength of the laser beam irradiated on the object to be processed is changed. apparatus. One surface selectively reflects laser light having a predetermined wavelength,
The reflection mirror, wherein the other surface facing the one surface selectively reflects laser light having a wavelength different from the predetermined wavelength. One area of one surface selectively reflects the laser beam having the predetermined wavelength,
The other region of the surface selectively reflects laser light having a wavelength different from the predetermined wavelength,
A region corresponding to one region of the one surface of the other surface selectively reflects laser light having a wavelength different from the predetermined wavelength,
10. The reflection mirror according to claim 9, wherein a region of the other surface corresponding to the other region of the one surface selectively reflects the laser light having the predetermined wavelength.

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