DE102014203525A1 - Apparatus and method for processing a workpiece - Google Patents

Abstract

The invention relates to a device (100) for machining a workpiece (130). The device (100) comprises a removal jet supply unit (110) which is designed to emit at least two removal jets (170a, 170b) spaced apart from one another at a predefined distance (d21) onto a workpiece (130). Furthermore, the device (100) comprises a movement unit (120) which is at least designed to linearly move the workpiece (130) relative to the removal jets (170a, 170b) so that at least a portion (167) of the workpiece (130) of each of the two Abtragsstrahlen (170a, 170b) is at least partially detected temporally one after the other.

Description

State of the art

The present invention relates to a device for processing a workpiece, to a corresponding method and to a corresponding computer program product.

In laser material processing, a laser beam is usually focused on or in a material. In the area of the focus, the absorbed intensity usually causes a heating, which then leads to a material removal or a material modification. In the following, for the sake of simplicity, only material removal will be discussed.

The lateral extent of the erosion zone caused by a laser beam is given by the extent of the beam profile, within which the intensity lies above the intensity required for erosion. This extension typically corresponds approximately to the diameter of the beam in the processing zone, which is also referred to as "spot".

If an elongate structure - for example, a trench - is to be generated by means of this technique, the most circular spot is moved by means of suitable techniques relative to the component. For this purpose, either the laser beam (for example, by means of a mirror) or with a fixed beam, the component (for example by means of axis system) are moved.

An experimental observation is that the quality of the processing usually depends very much on the type of process control. So it is usually advantageous to move the spot several times with lower power along the removal track, instead of doing this only once with higher performance. One speaks in these cases of "multiple crossings" respectively "single crossing". Multiple crossings, however, lead to longer processing times, which reduces productivity.

The publication US Pat. No. 7,935,941 B2 Figure 12 shows a semiconductor conductor structure processing using multi-laser beam spots spaced on one axis on non-adjacent structures.

Disclosure of the invention

Against this background, a device for processing a workpiece, furthermore a corresponding method and finally a corresponding computer program product according to the main claims are presented with the approach presented here. Advantageous embodiments emerge from the respective subclaims and the following description.

• – eine Abtragsstrahlbereitstellungseinheit, die ausgebildet ist, um zumindest zwei in einem vordefinierten Abstand voneinander beabstandete Abtragsstrahlen auf ein Werkstück auszusenden; und
• – eine Bewegungseinheit, die zumindest ausgebildet ist, um eine lineare Relativbewegung zwischen dem Werkstück und den Abtragsstrahlen zu bewirken, sodass zumindest ein Teilbereich des Werkstückes von jedem der beiden Abtragsstrahlen zeitlich nacheinander zumindest teilweise erfasst wird.

The approach presented here provides a device for machining a workpiece, the device having the following features:

• A Abtragsstrahlbereitstellungsseinheit, which is designed to emit at least two spaced apart in a predefined distance Abtragsstrahlen on a workpiece; and
• - A movement unit, which is at least formed to effect a linear relative movement between the workpiece and the Abtragsstrahlen, so that at least a portion of the workpiece of each of the two Abtragsstrahlen is sequentially at least partially detected.

In the present case, a removal jet can be understood as meaning a jet of a specific energy (such as, for example, a light or laser beam) or a jet of a specific medium (such as, for example, sand or water). In this case, the removal jets are designed to remove material from the workpiece upon impact with the workpiece, for example by thermal heating and evaporation or by mechanical removal from the workpiece. In the present case, a workpiece can be understood to mean an element to be processed, such as a semiconductor wafer or a printed circuit board, in which a structure is to be introduced or to be introduced. The erosion beams are aligned so that they are arranged at a predefined distance from each other and do not overlap or touch. Under a Abtragsstrahlbereitstellungsseinheit can thus be understood a unit that can align and output the at least two Abtragsstrahlen on the workpiece. A movement unit can be understood as meaning an assembly which can actively move the workpiece or the radiation delivery unit. The movement unit may cause, for example, mechanical movements of the workpiece in the form of further transport by a workpiece processing system or mechanical movement of a (beam steering) element of Abtragsstrahlbereitstellungsseinheit, such as the movement of a deflecting mirror when the Abtragsstrahlen are light rays. In this case, the movement unit is for example at least designed to move the workpiece linearly in a direction of movement which corresponds in a direction which is formed by a connecting line between the erosion beams.

The approach presented here is based on the knowledge that a uniform structuring or removal of material of a workpiece can take place in that a partial region of the workpiece is detected by different Abtragungsstrahlen, which are controlled together. Successively strike the relevant part of the workpiece. Such an approach has the advantage that a complex multiple passage of the area in question can be avoided, so that only a simple linear movement with the two ablation jets is carried out by the device presented here. In this way, a simple and quick structuring or machining of the workpiece can be done.

An embodiment of the present invention is advantageous in which the removal jet supply unit is designed to emit light beams, in particular laser beams, as removal beams. Such an embodiment of the present invention offers the advantage of designing the removal jets, jets technically very simple and easy to manage.

An embodiment of the present invention is very simple to implement in terms of technology, in which the removal jet provision unit has a beam splitter which is designed to form the two removal beams from a common source beam. A beam splitter can be understood as meaning an optical element which is designed to decouple at least two erosion beams from a (common) source beam. Such an embodiment of the present invention has the advantage that only one source for the source beam is to be provided, from which then the two ablation beams can be obtained.

Particularly advantageous is an embodiment of the present invention, wherein the ablating beam providing unit further comprises a focusing optical unit, wherein the beam splitter and the focusing optical unit are spaced from each other at a distance of a focal length of the focusing optical unit. Such an embodiment of the present invention offers the advantage of enabling a very good guidance of the removal jets, in particular wherein the at least two removal jets can be aligned approximately parallel.

In order to obtain an additional degree of freedom for the process control, according to an embodiment of the present invention, the beam splitter of the abrasive jet providing unit can be rotatably arranged with respect to the source beam. In this case, for example, the beam splitter can be moved or rotated around an angle section about a partial axis of the original beam.

Also conceivable is an embodiment of the present invention, in which the Abtragsstrahlbereitstellungsseinheit is formed to send the Abtragsstrahlen such that the Abtragsstrahlen have different intensities and / or benefits. Such an embodiment of the present invention offers the advantage of high flexibility in the structuring of the workpiece by the individual Abtragsstrahlen, in particular if a processing of the partial area of the workpiece can be better processed by two short successive beams, as if a single Abtragsstrahl multiple times, however for a longer time apart is guided over the relevant sub-area.

Particularly advantageous is an embodiment of the present invention, wherein the Abtragsstrahlbereitstellungsseinheit is formed to emit the two Abtragsstrahlen without mutual contact on the workpiece. In this way, the Abtragsstrahlen can develop their maximum effect.

Also, according to another embodiment of the present invention, the moving unit may be configured to move the workpiece such that the linear movement of the workpiece is performed in a direction predefined by a connecting line between the at least two abrasive beams. In this way, it can be ensured that the subregion is first processed by a first of the ablation jets, and then the same subregion, which has been processed by the first ablation jet, is likewise processed by the second, subsequent ablation jet. In this way, a high precision in the machining of the workpiece can be ensured with a low energy consumption for processing.

• – Aussenden von zumindest zwei in einem vordefinierten Abstand voneinander beabstandete Abtragsstrahlen auf ein Werkstück mittels einer Abtragsstrahlbereitstellungseinheit; und
• – Bewegen des Werkstückes und/oder zumindest eines Teils der Abtragsstrahlbereitstellungseinheit, um das Werkstück relativ zu den Abtragsstrahlen linear zu bewegen, sodass zumindest ein Teilbereich des Werkstückes von jedem der beiden Abtragsstrahlen zeitlich nacheinander zumindest teilweise erfasst wird.

Also, the approach presented herein provides a method of machining a workpiece, the method comprising the steps of:

• - emitting at least two ablation jets spaced apart from each other at a predefined distance onto a workpiece by means of a removal jet providing unit; and
• - Moving the workpiece and / or at least a portion of Abtragsstrahlbereitstellungsseinheit to move the workpiece relative to the Abtragsstrahlen linear, so that at least a portion of the workpiece from each of the two Abtragsstrahlen is sequentially at least partially detected.

The approach presented here also creates a device that is designed to perform the steps of a variant of a method presented here in appropriate facilities to drive or implement. Also by this embodiment of the invention in the form of a Device, the problem underlying the invention can be solved quickly and efficiently.

In the present case, a device can be understood as meaning an electrical device which processes sensor signals and outputs control and / or data signals in dependence thereon. The device may have an interface, which may be formed in hardware and / or software. In the case of a hardware-based embodiment, the interfaces can be part of a so-called system ASIC, for example, which contains a wide variety of functions of the device. However, it is also possible that the interfaces are their own integrated circuits or at least partially consist of discrete components. In a software training, the interfaces may be software modules that are present, for example, on a microcontroller in addition to other software modules.

A computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used for carrying out and / or controlling the steps of the method according to one of the embodiments described above is also of advantage in particular when the program product is executed on a computer or a device. In this respect, the approach presented here creates a computer program which is set up to carry out and / or control all steps of a variant of a method presented here.

The approach presented here will be explained in more detail below with reference to the accompanying drawings. Show it:

1 a block diagram of a device according to an embodiment of the present invention;

2 a representation of several Abtragsstrahlen when hitting the workpiece in a plan view according to an embodiment of the present invention;

3 Representations of the result of the approach presented here according to an embodiment for explaining its advantages; and

4 a flowchart of a method according to an embodiment of the present invention.

In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similar acting, with a repeated description of these elements is omitted.

1 a block diagram shows a device 100 for machining a workpiece according to an embodiment of the present invention. In this case, the device comprises 100 an abrasive jet delivery unit 110 as well as a movement unit 120 which is adapted to a on a holding element 125 arranged to be machined workpiece 130 to move. The abrasive jet delivery unit 110 includes in the in 1 illustrated embodiment, a laser source 135 , which is designed to be a source beam 140 on a mirror as a reflection element 145 to spend that of the mirror 145 on a beam splitter 150 is reflected. In the beam splitter 150 gets out of the original ray 140 a first partial beam 155a and a second sub-beam 155b formed, each focusing on a lens unit 160 be directed. The focusing unit 160 comprises a lens, here a converging lens, by means of the first partial beam 155 a is a first erosion beam 170a is formed. Analog becomes from the second partial beam 155b in the lens 165 a second removal jet 170b educated. The first erosion beam 170 a and the second Abtragsstrahl 170b then be on the workpiece 130 which is directed in a direction of movement by the movement unit 120 is moved. This will cause a relative movement 180 between the Abtragsstrahlbereitstellungsseinheit 110 and the motion unit 120 with the workpiece arranged thereon 130 causes, so a first sub-layer 130a a surface of the workpiece 130 in the subarea 167 of the workpiece 130 from the second erosion beam 170b is removed and temporally following a second sub-layer 130 b in the subarea 167 of the workpiece 130 through the first erosion beam 170a is removed, so after machining the workpiece 130 through the first erosion beam 170a and the second erosion beam 170b a third sub-layer 130c of the workpiece 130 exposes.

As will be described in more detail below, while the workpiece 130 from the movement unit 120 such in the direction of movement 180 moves that part of the workpiece 130 , which from the second erosion beam 170b is detected or illuminated, even if partially from the first Abstrahlsstrahl 170a recorded or illuminated. This can for example be done so that the relative movement 180 points in a direction through a connecting line 180 between the first order beam 170a and the second erosion beam 170b is defined. In this way it can be ensured that by the staggered passing over of the partial area 167 of the workpiece the effect of a Multiple crossing of subarea 167 of the workpiece 130 can be achieved, although practically or mechanically only a single relative movement 180 between the workpiece 130 and the abrasive jet providing unit 110 is done. In this way, the workpiece on the other hand gently and evenly, however, on the other hand can be processed quickly and efficiently.

• 1. Strahlteiler ortsfest, Laserspots ortsfest, Werkstück wird bewegt;
• 2. Strahlteiler wird bewegt, Laserspots bewegen sich mit, Werkstück ortsfest;
• 3. Strahlteiler ortsfest, Werkstück ortsfest, Laserspots werden nach Durchlaufen des Strahlteilers mit Kippspiegel auf der Werkstückoberfläche bewegt.

In principle, there are even more possibilities for the relative movement between laser spots and workpiece:

• 1. Beam splitter stationary, laser spot fixed, workpiece is moved;
• 2. Beam splitter is moved, laser spots move with, workpiece stationary;
• 3. Beam splitter stationary, workpiece stationary, laser spots are moved after passing through the beam splitter with tilting mirror on the workpiece surface.

All these possibilities of movement allow a simple realization of the advantages mentioned here.

An important aspect of the approach presented here can thus be seen in linking the system-technical advantages of single crossing with the advantages of multiple crossing in low-damage selective (here laser) ablation of thin layers, for example by means of pulsed laser radiation.

For this purpose, the laser spot proposed here, for example, is used as source beam 140 with suitable measures in several individual spots 170a and 170b split, which are arranged along an imaginary line. These spots 170a respectively. 170b are then moved along this imaginary line relative to the component, with each individual spot 170a respectively. 170b contributes to material processing.

2 shows a diagram for the machining of a workpiece in a situation with an exemplary division of the original laser beam 140 in three spots (erosion beams 170a . 170b , and 170c ) with individual distances d12 or d23 between the spots 170a . 170b and 170c , In this case, the third Abtragsstrahl 170 in a manner analogous to the first ablation beam 170a or the second erosion beam 170b from a source beam 140 be generated, even if this is in the 1 is not explicitly shown, but the extraction of two Abtragsstrahlen 170 through the beam splitter 150 from the source beam 140 is described.

Due to the spatial distances between the spots 170 it therefore comes along the removal track 200 effectively also to "multiple crossings", although only a single mechanical movement 180 takes place. Depending on the desired number of spots, the laser beam 140 through the beam splitting element 150 in corresponding many partial beams 155 divided up. By suitable distribution of the energy to the individual spots or erosion beams 170 In addition, the possibility arises to emulate multiple crossings with different energy in a single mechanical crossing.

Such multiple spots 170 can be from a laser beam 140 through a combination of the focusing optics 160 with upstream refractive, reflective or diffractive beam splitting elements 150 be generated. This is exemplified in 1 for the production of two spots 170 from a ray 140 shown. At the same time, the laser beam becomes 140 through a diffractive beam splitting element 150 in two partial beams 155a and 155b divided up. This results after passing through the focusing optics 160 to two consecutive spots 170 on the workpiece 130 , The distance d21 between the spots 170a and 170b can through the focal length of the focusing optics 160 respectively. 165 and / or the angle between the partial beams 155a and 155b in front of the focusing optics 160 be set. When the beam splitting element 150 at a distance from a focal length of the focusing element 160 respectively. 165 is arranged in front of this, run the individual partial beams 170 parallel to each other, this makes the structure more robust against variations in the beam direction. When the beam splitting element 150 around the direction of the original ray 140 rotatably mounted, the rapid removal can be realized in any direction. Should continue processing in 2 not from left to right, but z. For example, if you want to make a 45 degree turn from bottom left to top right, then the spot positions should also be rotated in such a way that they again run directly behind each other like a polonaise.

The approach presented here is mainly useful in applications where linear laser material removal is required. This is especially true in laser structuring of solar cells, in particular in the interconnection of thin-film solar modules (eg CIGS, a-Si / μc-Si,.

The result of using the approach presented here can be seen from the illustration 3 The approach proposed here has already been attempted in the structuring of the laser P2 process for CIGS solar cells. The 3 shows microscopic images of P2 laser structures produced by laser radiation. The goal is laser radiation here, a thin molybdenum layer as the third sub-layer 130c low-emission. In the left illustration the result after a single crossing is one Single beam at a relative speed of 30 mm / s shown. In the middle illustration, the result is shown after a 9-fold of a single beam at a relative speed of 400 mm / s. In the right-hand illustration, the result is after a single crossing of a 6-times divided source beam or of six removal beams aligned in accordance with the approach presented here 170 shown at a relative speed of 220 mm / s. It is off the chart 3 recognizable that by the approach presented here, a very sharp boundary line of the removal track 200 can be achieved while high processing speed can be.

Based on the pictures from the 3 It can be seen that the use of the multispot method according to the right-hand illustration results in a speed increase over the conventional structuring a) (from 30 mm / s to 220 mm / s).

4 shows a flowchart of a method 400 for machining a workpiece according to an embodiment of the present invention. The procedure 400 includes a step 410 the emission of at least two ablation jets spaced apart from each other at a predefined distance on a workpiece. Furthermore, the method comprises 400 one step 420 moving the workpiece to linearly move the workpiece relative to the abrasive jets such that at least a portion of the workpiece is at least partially sequentially timed by each of the two abrasive jets.

The embodiments described and shown in the figures are chosen only by way of example. Different embodiments may be combined together or in relation to individual features. Also, an embodiment can be supplemented by features of another embodiment.

Furthermore, the method steps presented here can be repeated as well as executed in a sequence other than that described.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment either only first feature or only the second feature.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7935941 B2 [0006]

Claims (11)

Contraption ( 100 ) for machining a workpiece ( 130 ), the device ( 100 ) has the following features: a removal jet delivery unit ( 110 ), which is designed to be at least two at a predefined distance ( d21 ) Abtragsstrahlen spaced from each other ( 170a . 170b ) on a workpiece ( 130 ) to send out; and a movement unit ( 120 ), which is at least adapted to a linear relative movement between the workpiece ( 130 ) and the Abtragsstrahlen ( 170a . 170b ), so that at least one subregion ( 167 ) of the workpiece ( 130 ) of each of the two abrasive beams ( 170a . 170b ) is at least partially detected in chronological order. Contraption ( 100 ) according to claim 1, characterized in that the Abtragsstrahlbereitstellungsseinheit ( 110 ) is designed to act as erosion beams ( 170a . 170b ) Emit light beams, in particular laser beams. Contraption ( 100 ) according to one of the preceding claims, characterized in that the ablation jet supply unit ( 110 ) a beam splitter ( 150 ), which is designed to hold the two removal beams ( 170a . 170b ) from a common source beam ( 140 ) to build. Contraption ( 100 ) according to claim 3, characterized in that the Abtragsstrahlbereitstellungsseinheit ( 110 ) further comprises a focusing optical unit ( 160 . 165 ), in particular wherein the beam splitter ( 150 ) and the focusing optical unit ( 160 . 165 ) at a distance of a focal length of the focusing optical unit ( 160 . 165 ) are spaced from each other. Contraption ( 100 ) according to one of claims 3 or 4, characterized in that the beam splitter ( 150 ) of the Abtragsstrahlbereitstellungsseinheit ( 110 ) rotatable relative to the original jet ( 140 ) is arranged. Contraption ( 100 ) according to one of the preceding claims, characterized in that the ablation jet supply unit ( 110 ) is adapted to the Abtragsstrahlen ( 170a . 170b ) in such a way that the erosion beams ( 170a . 170b ) have different intensities and / or benefits. Contraption ( 100 ) according to one of the preceding claims, characterized in that the ablation jet supply unit ( 110 ) is formed to the two Abtragsstrahlen ( 170a . 170b ) without mutual contact on the workpiece ( 130 ). Contraption ( 100 ) according to one of the preceding claims, characterized in that the movement unit ( 120 ) is formed around the workpiece ( 130 ) such that the one linear movement ( 180 ) of the workpiece ( 130 ) is executed in a direction passing through a connecting line ( 185 ) between the at least two erosion beams ( 170a . 170b ) is predefined Procedure ( 400 ) for machining a workpiece ( 130 ), the process ( 400 ) comprises the following steps: - sending ( 410 ) of at least two at a predefined distance spaced Abtragsstrahlen ( 170a . 170b ) on a workpiece ( 130 ) by means of a Abtragsstrahlbereitstellungsseinheit ( 110 ); and - moving the workpiece ( 130 ) and / or at least part of the ablation jet providing unit ( 110 ) to the workpiece ( 130 ) relative to the erosion beams ( 170a . 170b ) to move linearly, so that at least a portion ( 167 ) of the workpiece ( 130 ) of each of the two abrasive beams ( 170a . 170b ) is at least partially detected in chronological order. Computer program adapted to perform all steps of a procedure ( 400 ) according to claim 9 and / or to control. A machine-readable storage medium having a computer program stored thereon according to claim 10.

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