Laser processing device

Abstract

Laser processing device (1) for processing semiconductor wafers as workpieces, comprising: a first laser mechanism (1a) comprising a first clamping table (36) for holding a first workpiece, a first X-movement means (37) for moving the first clamping table (36) in an X direction, a first Y-movement means (38) for moving the first clamping table (36) in a Y direction perpendicular to the X direction, and a first focusing means (51) for focusing a first laser beam (LB1) on the first workpiece held on the first clamping table (36); a second laser mechanism (1b) comprising a second clamping table (36') for holding a second workpiece, a second X-movement means (37') for moving the second clamping table in the X direction, a second Y-movement means (38') for moving the second clamping table (36') in the Y direction, and a second focusing means (51') for focusing a second laser beam (LB2) on the second workpiece held on the second clamping table (36'); a laser oscillator for oscillating an original laser beam; an optical system for splitting the original laser beam oscillated by the laser oscillator and guiding the first (LB1) and second laser beams (LB2) respectively to the first (51) and second focusing means (51'); a first control panel (202) for setting a first processing condition for the first laser mechanism (1a); and a second control panel (205) for setting a second processing condition for the second laser mechanism (1b), wherein the first control panel (202) is attached to the laser processing device (1) at a different position than the second control panel (205), wherein the optical system (5) also includes a half-wave plate (53) and a polarization beam splitter (54), the half-wave plate (53) being inserted between the laser oscillator and the polarization beam splitter (54), By rotating the half-wave plate in the original laser beam, the intensity ratio between the first laser beam (LB1) as S-polarized light and the second laser beam (LB2) as P-polarized light, which are emitted by the polarization beam splitter (54), is continuously variable, and In the optical system, a setting agent (57) for a first wavelength and a setting agent (61) for a second wavelength are provided in an optical path of the first laser beam (LB1) and the second laser beam (LB2), which have passed through a first damper (56) and a second damper (60).

Description

BACKGROUND OF THE INVENTION Technical field

[0001] The present invention relates to a laser processing device for processing a workpiece such as a semiconductor wafer by applying a laser beam to it. Description of the state of the art

[0002] In a process for fabricating multiple semiconductor device chips using a laser processing device, several intersecting parting lines are formed on the front face of an essentially disk-shaped semiconductor wafer to create multiple separate regions, each containing multiple semiconductor devices such as integrated circuits (ICs) and large-scale integration (LSI) circuits. The semiconductor wafer is then cut along the parting lines by applying a laser beam, separating the regions containing the semiconductor devices and thus yielding the individual semiconductor device chips.

[0003] The laser processing device includes a clamping table for holding a workpiece, a laser beam application means for applying a laser beam to the workpiece held on the clamping table, and a feed means for feeding the clamping table, wherein the laser beam application means includes a laser oscillator for oscillating a laser beam, a focusing means for focusing the laser beam oscillated by the laser oscillator in order to apply the focused laser beam to the workpiece held on the clamping table, and a damper provided between the laser oscillator and the focusing means for adjusting the power of the laser beam, thereby performing the desired laser processing on the workpiece (see, for example, patent application JP 2010 - 158 691 A).

[0004] Furthermore, in many cases, the laser oscillator used in the laser processing device is designed to oscillate a laser beam with a relatively high power to support various types of processing. Accordingly, the damper is generally used to reduce the power of the laser beam to a level suitable for the workpiece.

[0005] US 4,653,903 A concerns an exposure device. WO 1996 / 011769 A1 concerns a laser processing device. JP 2008 - 110 383 A concerns a laser processing device. DE 697 26 361 T2 relates to a device for manufacturing a plate. DE 10 2006 022 304 A1 relates to a method for the decentralized control of a processing machine. PRESENTATION OF THE INVENTION

[0006] As described above, the laser beam generated by the laser oscillator in the laser processing device is used at a reduced power level after its output has been adjusted. For example, half or less of the power originally provided by the laser oscillator is used for laser processing of the workpiece. In this case, half or more of the laser beam's power is wasted. Consequently, the laser oscillator's power cannot be used effectively, resulting in poor efficiency.

[0007] Therefore, an objective of the present invention is to provide a laser processing device which can make sufficient use of the power of a laser oscillator capable of oscillating a high-power laser beam.

[0008] The invention resulting from this objective is defined by independent claim 1.

[0009] In accordance with one aspect of the present invention, a laser processing device is provided comprising a first laser mechanism comprising a first clamping table for holding a first workpiece, a first X-movement means for moving the first clamping table in an X direction, a first Y-movement means for moving the first clamping table in a Y direction perpendicular to the X direction, and a first focusing means for focusing a first laser beam onto the workpiece held on the first clamping table; a second laser mechanism comprising a second clamping table for holding a workpiece, a second X-movement means for moving the second clamping table in the X direction, a second Y-movement means for moving the second clamping table in the Y direction, and a second focusing means for focusing a second laser beam onto the second workpiece held on the clamping table;a laser oscillator for oscillating an original laser beam; an optical system for splitting the original laser beam, which is oscillated by the laser beam oscillator, into the first and second laser beams to the first and second focusing means; a first control panel for setting a first processing condition for the first laser mechanism; a second control panel for setting a second processing condition for the second laser mechanism.

[0010] The optical system also includes a half-wave plate and a polarization beam splitter, wherein the half-wave plate is inserted between the laser oscillator and the polarization beam splitter, and wherein, by rotating the half-wave plate at the original laser beam, the intensity ratio between the first laser beam as S-polarized light and the second laser beam as P-polarized light, which are emitted by the polarization beam splitter, is continuously variable.

[0011] Preferably, the laser processing device further comprises a housing for covering the first laser mechanism and the second laser mechanism; wherein the housing is provided with a first flap in a position where the workpiece is loaded to the first laser mechanism, and a second flap in a position where the second workpiece is loaded to the second laser mechanism; wherein the first and second control panels are mounted on the first and second flaps, respectively; the first flap and the second flap are arranged parallel in the Y direction on a plane perpendicular to the X direction.

[0012] Preferably, the first clamping table is moved by the first X-movement means between a holding area, at which the workpiece is held or released with respect to the first clamping table, and a first processing area, at which the first laser beam is applied by the first focusing means to the first workpiece, which is held at the first clamping table; wherein the first holding area includes a first cassette table for mounting a first cassette that receives the first workpiece, a first temporary setting means for temporarily setting down the first workpiece, a first handling means for picking up the first workpiece from the first cassette that is mounted on the first cassette table, and then carrying the first workpiece to the first temporary setting means, and a first transfer means for transferring the first workpiece from the first temporary setting means to the first clamping table;wherein the first flap is open to / from the first cassette table when loading / unloading the first cassettes; and the second clamping table is moved by the second X-movement means between a second holding area, at which the second workpiece is held or released with respect to the second clamping table, and a second processing area, at which the second laser beam is applied by the second focusing means to the second workpiece, which is held at the second clamping table;wherein the second holding area includes a second cassette table for mounting a second cassette which holds the second workpiece, a second temporary holding device for temporarily setting down the second workpiece, a second handling device for picking up the second workpiece from the second cassette which is mounted on the second cassette table, and then carrying the second workpiece to the second temporary holding device, and a second transfer device for transferring the second workpiece from the second temporary holding device to the second clamping table; wherein the second flap is open when loading / unloading the second cassette to / from the second cassette table.

[0013] According to the laser processing device of the present invention, the power of the individual laser oscillator is divided to form a two-laser mechanism. This means that essentially two laser processing devices can be provided. Furthermore, the first and second control panels for actuating the first and second laser mechanisms are arranged to correspond to the first and second laser mechanisms, respectively. Accordingly, the power of the laser oscillator can be used efficiently, and two types of laser processing can be performed simultaneously, thus achieving good economic efficiency. Moreover, since the laser oscillator for oscillating a laser beam is expensive, the cost of the laser processing device can be reduced by essentially half.

[0014] Furthermore, in the laser processing device of the present invention, the first control panel is mounted on the first flap and the second control panel is mounted on the second flap. The first flap and the second flap are mounted parallel in the Y direction on a plane perpendicular to the X direction. With this arrangement, the laser mechanism can be efficiently operated by each of the two control panels.

[0015] Furthermore, the first clamping table is moved by the first X-movement means between a first holding area, where the workpiece is held or released with respect to the first clamping table, and a first processing area, where the first laser beam is applied by the first focusing means to the first workpiece held on the first clamping table, wherein the first holding area includes a first cassette table for mounting a first cassette which receives the first workpiece, a first temporary setting means for temporarily setting down the first workpiece, a first handling means for removing the first workpiece from the first cassette which is mounted on the first cassette table, and then carrying the first workpiece to the first temporary setting means, and a first transfer means for transferring the first workpiece from the first temporary setting means to the first clamping table.Furthermore, the first flap is opened when loading / unloading the first cassette to / from the first cassette table.Similarly, the second clamping table is moved by the second X-movement means between a second holding area, where the second workpiece is held or released with respect to the second clamping table, and a second processing area, where the second laser beam is applied by the second focusing means to the second workpiece, which is held against the second clamping table, wherein the second holding area includes a second cassette table for mounting a second cassette that receives the second workpiece, a second temporary setting means for temporarily setting down the second workpiece, a second handling means for picking up the second workpiece from the second cassette that is mounted on the second cassette table, and then carrying the second workpiece to the second temporary setting means, and a second transfer means for transferring the second workpiece from the second temporary setting means to the second clamping table.Accordingly, there is no possibility that, if the first flap is open when loading the first cassette onto the first cassette table, an operator could mistakenly operate the first control panel to start the first laser mechanism. A similar effect can also occur if the second flap is open.

[0016] The above and other aims, features and advantages of the present invention and the manner of realizing them will become clearer, and the invention itself will best be understood by studying the following description and attached claims with reference to the attached figures, which show a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a perspective view of a laser processing device according to a preferred embodiment of the present invention; Fig. 2 its perspective view, showing an essential part of the laser processing device, which is in Fig. 1 is shown; Fig. 3 is a block diagram of an application means for a laser beam, which is used in the laser processing device that is in Fig. 1 is shown, includes; Fig. Figure 4 is a perspective view of a first and second cassette table mechanism included in the laser processing device shown in Fig. 1 is shown; Fig. Figure 5 is a perspective view of a first and second temporary setting agent included in the laser processing device, which is in Fig. 1 is shown Fig. Figure 6 is a perspective view of a first and second handling mechanism used in the laser processing device, which is in Fig. 1 is shown, includes; Fig. Figure 7 is a perspective view of a first and second transfer medium used in the laser processing device, which is in Fig. 1 is shown, includes; Fig. Figure 8 is a perspective view showing a condition in which the first handling device is positioned to pick up a semiconductor from a first cassette located on the first cassette table mechanism in the laser processing device, which is in Fig. 1 is shown, is set off; Fig. 9 is a view similar to Fig. 8, which shows a condition in which the semiconductor wafer being processed by the first handling mechanism is temporarily deposited on the first temporary setting agent; Fig. 10 is a view similar to Fig. 8, which shows a condition in which the semiconductor wafer, which is temporarily deposited on the first temporary setting medium, is held by the first transfer medium; Fig. 11 is a view similar to Fig. 8, which shows a condition in which the semiconductor wafer, held by the first transfer means, is transferred and on a first clamping table included in the laser processing device, which is in Fig. 1 is shown, is set off; and Fig. 12 its perspective view, which shows a condition in which the laser processing device, which is in Fig. As shown in 1, it is enclosed by a housing. DETAILED DESCRIPTION OF THE PREFERRED VERSION

[0017] A preferred embodiment of the laser processing device according to the present invention is described in detail below with reference to the attached figures. Fig. Figure 1 is a perspective view of a laser processing device 1 according to this preferred embodiment. The laser processing device 1, which is shown in Fig. As shown in Figure 1, the assembly comprises a stationary base 2, a first clamping table mechanism 3 for holding a first workpiece, wherein the first clamping table mechanism 3 is provided on the stationary base 2 so that it is movable in the X direction, indicated by arrow X, a second clamping table mechanism 3' for holding a second workpiece, wherein the second clamping table 3' is provided on the stationary base 2 parallel to the first clamping table mechanism 3 so that it is movable in the X direction, and an application unit 4 for a laser beam, which is provided on the stationary base 2 in a central area formed between the first and second clamping table mechanisms 3 and 3'. A first laser mechanism 1a, which includes the first clamping table mechanism 3, is located on the front side, as shown in Figure 1. Fig. 1 seen, formed and a second laser mechanism 1b, which includes the second clamping table mechanism, is on the rear side, as in Fig. 1 seen, trained.

[0018] Fig. Figure 2 is a perspective view showing in detail the setup of a laser processing device 1, which is located in Fig. 1 is shown. That is, Fig. Figure 2 shows a condition obtained by removing a first and second cassette table mechanism 7 and 7', a first and second temporary setting means 8 and 8', a first and second handling means 9 and 9', and a first and second transfer means 10 and 10' from the stationary base 2. As in Fig. As shown in Figure 2, the laser beam application unit 4 is provided at a substantially central position on the stationary base 2, and the first clamping table mechanism 3 is located on the front side of the laser beam application unit 4, as shown in Figure 2. Fig. 2 seen, provided. The first clamping table mechanism 3 includes a pair of parallel guide rails 31 provided on the stationary base 2 so that they extend in the X direction, a motion base 32 which is slidably provided on the guide rails 31 so that it is movable in the X direction, a sliding block 33 which is slidably provided on the motion base 32 so that it is movable in a Y direction, indicated by an arrow Y perpendicular to the X direction, a cover table 35 which is supported by a cylindrical element 34 which stands on the first sliding block 33, and a first clamping table 36 (first holding device) for holding the first workpiece. The first clamping table 36 has a vacuum clamping device 361 which is made of a porous material.The first workpiece is adapted so that it is held under suction on the upper surface of the vacuum clamping device 361 as a holding surface by actuating a suction device (not shown). The first clamping table 36 is rotatable by a pulse motor (not shown) provided in the cylindrical element 34. The first clamping table 36 is equipped with clamps 362 for fixing an annular frame F (see . Fig. 1), which carries a semiconductor wafer W as the first workpiece through a protective belt T.

[0019] The lower surface of the motion base 32 is provided with a pair of guide grooves 321 for sliding engagement of the pair of guide rails 31 mentioned above. A pair of parallel guide rails 322 is provided on the upper surface of the motion base 32, extending in the Y direction. Accordingly, the motion base 32 is movable in the X direction along the guide rails 31 by the sliding engagement of the guide grooves 321 with the guide rails 31. The first clamping table mechanism 3 further includes a first X-movement means 37 for moving the motion base 32 in the X direction along the guide rails 31. The first X-movement means 37 includes a threaded rod 371 extending parallel to the guide rails 31, so that it lies between them, and a pulse motor 372 as a drive source for rotating the threaded rod 371.The threaded rod 371 is rotatably fixed at one end to a bearing block 373 on the stationary base 2 and is connected at the other end to the output shaft of the pulse motor 372 to receive torque from it. The threaded rod 371 engages with a threaded bore in a block with an internal thread (not shown) that projects from the lower surface of the motion base 32 at a central distance from it. Accordingly, the motion base 32 is moved in the X direction along the guide rails 31 by actuating the pulse motor 372, which rotates the threaded rod 371 normally or in reverse.

[0020] The first clamping table mechanism 3 is equipped with an X-position detection means (not shown) to detect the X-position of the first clamping table 36. The X-position detection means is configured to transmit a pulse signal of, for example, one pulse per micrometer to a control means (not shown). The control means counts the number of pulses as the input pulse signal from the X-position detection means in order to detect the X-position of the first clamping table 36. In the case that the pulse motor 372 is used as the drive source for the X-movement means 37, as in the preferred embodiment, the number of pulses can be counted as a drive signal output by the control means to the pulse motor 372 in order to detect the X-position of the first clamping table 36.In the case that a servo motor is used as the drive source for the first X-movement means 37, a pulse signal output by a rotary encoder to detect the rotational speed of the servo motor can be sent to the control means and the number of pulses input as the pulse signal from the rotary encoder to the control means can be counted by the control means in order to detect the X position of the first clamping table 36.

[0021] The lower surface of the sliding block 33 is provided with a pair of guide grooves 331 for sliding engagement with the pair of guide rails 322 on the upper surface of the motion base 32, as described above. Accordingly, the sliding block 33 is movable in the Y direction along the guide rails by means of the sliding engagement of the guide grooves 331 with the guide rails 322. The first clamping table mechanism 3 further includes a first Y-movement element 38 for moving the sliding block 33 in the Y direction along the guide rails 322. The first Y-movement element 38 includes a threaded rod 381 extending parallel to the guide rails 322, so that it is positioned between them, and a pulse motor 382 as a drive source for rotating the threaded rod 381.The threaded rod 381 is rotatably fixed at one end to a bearing block 383 on the upper surface of the motion base 32 and is connected at the other end to the shaft of the pulse motor 382 to receive torque from it. The threaded rod 381 engages with a threaded bore formed on a block with an internal thread (not shown) that projects from the lower surface of the sliding block 33 at a central section thereof. Accordingly, the sliding block 33 is moved in the Y direction along the guide rails 322 by actuating the pulse motor 382, ​​which rotates the threaded rod 381 normally or in the opposite direction.

[0022] The first clamping table mechanism 3 is equipped with a Y-position detection device (not shown) to detect the Y-position of the first clamping table 36. The configuration of the Y-position detection device is similar to that of the X-position detection device described above. That is, the Y-position detection device is configured to transmit, for example, a pulse signal of one pulse per micrometer to the control device. The control device counts the number of pulses as the pulse signal input from the Y-position detection device to detect the Y-position of the first clamping table 36.In the case where the pulse motor 382 is used as the drive source for the first Y-movement device 38, as in the preferred embodiment, the number of pulses can be counted by the control device as a drive signal output to the pulse motor 382 in order to detect the Y-position of the first clamping table 36. In the case where a servo motor is used as the drive source for the first Y-movement device 38, a pulse signal output by a rotary encoder to detect the rotational speed of the servo motor can be sent to the control device, and the number of pulses input by the rotary encoder to the control device can be counted by the control device in order to detect the Y-position of the first clamping table 36.

[0023] As in Fig. Figure 2 shows the second clamping table mechanism 3' provided at the rear of the laser beam delivery unit 4, which is located at the central area of ​​the stationary base 2. This means that the laser beam delivery unit 4 is positioned between the first clamping table mechanism 3 and the second clamping table mechanism 3' in the Y direction. Similar to the first clamping table mechanism 3, the second clamping table mechanism 3' includes a second clamping table 36' (second holding device) for holding the second workpiece, a second X-movement device 37' for moving the second clamping table 36' in the X direction, and a second Y-movement device 38' for moving the second clamping table 36' in the Y direction. Fig. 2 are essentially the same parts as those of the first clamping table mechanism 3, marked by the same reference numerals with " ' " and the actuation of the second clamping table mechanism 3' is essentially the same as that of the first clamping table mechanism 3, so a detailed description of it is omitted here.

[0024] The laser beam delivery unit 4 comprises a support element 41, which is provided on the stationary base 2, and a housing 42, which is supported on the support element 41. The housing 42 includes a pair of branch sections 42a and 42b, which extend horizontally to the first and second clamping table mechanisms 3 and 3', respectively. An optical system, forming a laser beam delivery device 5, which is described below, is incorporated in the branch sections 42a and 42b. A pair of first and second focusing devices 51 and 51', which form part of the laser beam delivery device 5, are provided on the branch sections 42a and 42b, respectively.Furthermore, a pair of first and second imaging means 6 and 6' for detecting a target area to be laser-processed is also provided at branch sections 42a and 42b, respectively, with the first and second imaging means 6 and 6' being located near the first and second focusing means 51 and 51'. Each of the first and second imaging means 6 and 6' comprises a light source for illuminating a workpiece, an optical system for capturing an area illuminated by the light source, and an imaging device (a charge-coupled device (CCD)) for capturing the area enclosed by the optical system. An image signal output by each of the first and second imaging means 6 and 6' is transmitted to the control device.

[0025] The application medium 5 for the laser beam is described in detail below with reference to Fig. 3 described. The laser beam delivery device 5 comprises an oscillator device 52 for a pulsed laser beam, a half-wave plate 53 provided in a branched optical path, a polarization beam splitter 54, a first and second beam shutter 55 and 59, first and second dampers 56 and 60, first and second setting devices 57 and 61 for one wavelength, first and second half-wave plates 58 and 62 provided in the branched first and second optical path, and the first and second focusing devices 51 and 51'. The oscillator device 52 for the pulsed laser beam comprises a laser oscillator and a setting device for one repetition frequency (both not shown), wherein the oscillator device 52 for the pulsed laser beam oscillates a laser beam LB having, for example, a wavelength of 1064 nm and a repetition frequency of 50 kHz.The laser beam LB is split into a first laser beam LB1 (first optical path) and a second laser beam LB2 (second optical path) by the polarization beam splitter 54, wherein the first laser beam LB1 is S-polarized light that is reflected by the polarization beam splitter 54, and the second laser beam LB2 is P-polarized light that is transmitted by the polarization beam splitter 54.

[0026] The half-wave plate 53 is inserted between the oscillator 52 for the pulsed laser beam and the polarization beam splitter 54. The rotation angle of the half-wave plate 53 is adjusted by an adjustment means for a rotation angle (not shown), thereby enabling a rotation of the polarization plane of the light arriving from the half-wave plate 53. Accordingly, by rotating the half-wave plate 53, the intensity ratio between the first laser beam LB1, which is S-polarized light, and the second laser beam LB2, which is P-polarized light, emitted by the polarization beam splitter 54, is continuously changed.

[0027] The first and second beam shutters 55 and 59 are arranged in the optical paths of the first and second laser beams LB1 and LB2, respectively, which are emitted by the polarization beam splitter 54. Each of the first and second beam shutters 55 and 59 is provided with a shutter drive device (not shown), wherein the first shutter 55 can be driven to a position in which the first laser beam LB1 is interrupted and a position in which the first laser beam LB1 is not interrupted, and the second beam shutter 59 can be driven to a position in which the second laser beam LB2 is interrupted and a position in which the second laser beam LB2 is not interrupted.Accordingly, the first and second beam splitters 55 and 59 can be operated so that they can select a suitable mode in which only the first laser beam LB1 is applied to the first workpiece, a mode in which only the second laser beam LB2 is applied to the second workpiece, or a mode in which both the first and second laser beams LB1 and L2 are applied to the first and second workpieces.

[0028] The first and second laser beams LB1 and LB2, which have passed through the first and second beam shutters 55 and 59, are adjusted in intensity by the first and second dampers 56 and 60, respectively. Each of the first and second dampers 56 and 60 can be provided by a variable damper for a laser beam, as known in the prior art, whereby the laser intensity can be variably adjusted according to a process condition required for each workpiece.

[0029] The damping elements 57 and 61 for the first and second wavelengths are provided in the optical path of the first and second laser beams LB1 and LB2, which have passed through the first and second damping elements 56 and 60, respectively. For example, the wavelength (1064 nm) of the laser beam, which has been oscillated by the oscillator element 52 for the laser beam, can be converted to a wavelength of 532 nm by passing it through a nonlinear crystal, or to a wavelength of 355 nm by passing the laser beam through a single crystal.The first and second wavelength setting devices 57 and 61 can be activated to select a suitable mode in which the transmission wavelength (1064 nm) is used for each workpiece to form a modified layer, or a mode in which the absorption wavelength (355 nm) is used for each workpiece to perform ablation of the top surface of each workpiece. Accordingly, by setting the first and second wavelength setting devices 57 and 61 in the first optical path, the wavelengths of the first and second laser beams LB1 and LB2 can be set differently.

[0030] The first and second half-wave plates 58 and 62 are positioned in the optical path of the first and second laser beams LB1 and LB2, which have passed through the first and second setting means 57 and 61 for the respective wavelengths. Each of the first and second half-wave plates 58 and 62 is provided with a drive means for rotation (not shown). Accordingly, the first half-wave plate 58 can be rotated to adjust the direction of the polarization plane of the first laser beam LB1 according to the material of the first workpiece. Similarly, the half-wave plate 62 can be rotated to adjust the direction of the polarization plane of the second laser beam LB2 according to the material of the second workpiece.

[0031] The first and second laser beams LB1 and LB2, which pass through the first and second half-wave plates 58 and 62, enter the first and second focusing devices 51 and 51', respectively, which are provided at the ends of the first and second optical paths. Each of the first and second focusing devices 51 and 51' contains a focusing lens. Accordingly, the first laser beam LB1 is focused on the first workpiece, which is held on the clamping table 36, by the focusing lens of the first focusing device 51. Similarly, the second laser beam LB2 is focused on the second workpiece, which is clamped on the second clamping table 36', by the focusing lens of the second focusing device 51'.

[0032] The optical system of the laser beam delivery device 5, mentioned above, is housed in the branch sections 42a and 42b of the housing 42, which is located in a substantially central position on the stationary base 2, such that it lies between the first and second clamping table mechanisms 3 and 3'. The first and second focusing devices 51 and 51' are provided at the ends of the branch sections 42a and 42b, where the first and second focusing devices 51 and 51' are positioned opposite the first and second clamping tables 36 and 36', respectively. That is, the first and second focusing devices 51 and 51' are positioned opposite the first and second processing areas, where laser processing is performed on the first and second workpieces, which are held on the first and second clamping tables 36 and 36', respectively.

[0033] In this preferred embodiment, each of the X and Y motion means mentioned above includes a threaded rod parallel to a pair of guide rails, an internally threaded block incorporating a threaded bore provided on the lower surface of a motion base or sliding block and engaging in screw thread with the threaded rod, and a pulse motor as a drive source for rotating the threaded rod. However, this configuration is for illustrative purposes only.For example, each of the X and Y motion means can be provided by a so-called linear shaft motor, which includes a straight rail extending in the X direction or the Y direction in place of the threaded rod, and a movable coil element that is in movable engagement with the straight rail in such a way that the straight rail is inserted through the movable coil element, the movable coil element being provided on a motion base or sliding block above the clamping table.

[0034] With reference to Fig. 1 The first and second cassette table mechanism 7 and 7' for mounting the first and second cassettes 70 and 70', in which several of the first workpieces such as the semiconductor wafers and several of the second workpieces such as the semiconductor wafers are held, the first and second temporary setting devices 8 and 8' for temporarily setting down the first and second workpiece that has been taken from the first and second cassette 70 and 70', are provided on the stationary base 2.The first and second handling devices 9 and 9' are provided for removing the first and second workpieces from the first and second cassettes 70 and 70' before machining and for returning the first and second workpieces to the first and second cassettes 70 and 70' after machining; and the first and second transfer devices 10 and 10' are provided for transferring the first and second workpieces from the first and second temporary holding devices 8 and 8' to the first and second clamping tables 36 and 36' before machining and for transferring the first and second workpieces from the first and second clamping tables 36 and 36' to the first and second temporary holding devices 8 and 8' after machining.

[0035] This cassette table mechanism 7 and 7', the temporary setting agent 8 and 8', handling agent 9 and 9', and transfer agent 10 and 10' are described in detail below. As in Fig. 1 and Fig. As shown in Figure 4, the cassette table mechanism 7 is provided adjacent to a first holding area where the first workpiece is held on the clamping table 36 of the first clamping table mechanism 3 before machining and released from the first clamping table 36 after machining. Similarly, the second cassette table mechanism 7' is provided adjacent to a second holding area where the second workpiece is held on the second clamping table 36' of the second clamping table mechanism 3' before machining or released from the second clamping table 36' after machining. The first and second cassette table mechanisms 7 and 7' include a first and second cassette table 71 and 71' for mounting the first and second cassettes 70 and 70', respectively. Each of the first and second cassette tables 71 and 71' is vertically movable by a lifting device (not shown).

[0036] The first and second temporary setting agents 8 and 8' are referred to below with reference to the Fig. 1 and Fig. 5 described. The first and second temporary holding devices 8 and 8' are located adjacent to the first and second cassette table mechanisms 7 and 7', respectively, in the X direction. In particular, the first temporary holding device 8 is located directly above the first holding area in which the first workpiece is held or released with respect to the first clamping table 36. Similarly, the second temporary holding device 8' is located directly above the second holding area in which the second workpiece is held or released with respect to the second clamping table 36'. As described in Fig. As shown in Figure 5, the first temporary setting device 8 comprises a pair of parallel, L-shaped support rails 81a and 81b extending in the X direction, and a movement device 82 for the support rails to carry end sections of the support rails 81a and 81b, thus enabling movement of the support rails 81a and 81b in the Y direction, thereby allowing a change in the distance between the support rails 81a and 81b. Similarly, the second temporary setting device 8' comprises a pair of parallel, L-shaped support rails 81a' and 81b' extending in the X direction, and a movement device 82' for the support rails 81a' and 81b' to enable movement of the support rails 81a' and 81b' in the Y direction, thereby changing the distance between the support rails 81a' and 81b'.The distance between the support rails 81a and 81b is set such that when the support rails 81a and 81b are moved towards each other, this distance becomes smaller than the outer diameter of the annular frame F, which carries the semiconductor wafer W as the first workpiece through the protective band T (in particular, this distance is the distance between horizontal sections of the support rails 81a and 81b), whereas when the support rails 81a and 81b move away from each other, this distance becomes larger than the outer diameter of the annular frame F.Similarly, the distance between the support rails 81a' and 81b' is set such that when the support rails 81a' and 81b' are moved towards each other, the distance becomes smaller than the outer diameter of the annular frame F, which carries the semiconductor wafer W as the second workpiece through the protective band T (in particular, this distance is the distance between horizontal sections of the support rails 81a' and 81b'), whereas when the support rails 81a' and 81b' are moved away from each other, this distance becomes larger than the outer diameter of the annular frame F.

[0037] The first and second handling devices 9 and 9' are referred to below in relation to Fig. 1 and Fig. 6 described. The first handling means 9 includes a handling arm 91, a catching element 92 provided at an end section of the handling arm on the side opposite the first cassette table mechanism 7 for catching the annular frame F, which carries the semiconductor wafer W as the first workpiece received in the first cassette 70, and a movement means 93 for the arm for carrying the handling arm 91 in order to enable the movement of the handling arm 91 in the X direction.Similarly, the second handling means 9' includes a handling arm 91', a grasping element 92' provided at an end section of the handling arm 91' on the side opposite the second cassette table mechanism 7' for grasping the annular frame F, which carries the semiconductor wafer W as the second workpiece held in the second cassette 70', and a movement means 93' for an arm to support the handling arm 91', thus enabling movement of the handling arm 91' in the X direction. Each of the grasping elements 92 and 92' is driven by air pressure supplied by an air cylinder (not shown), thereby grasping the annular frame F.

[0038] The first and second transfer agents 10 and 10' are used in relation to Fig. 1 and Fig. The first transfer means 10 comprises several suction grippers 11 for holding the annular frame F, which carries the semiconductor wafer W as the first workpiece, under suction; a transfer arm 12 having a front end on which the suction grippers are located; an actuating rod 13 for vertically moving the transfer arm 12; and an elevation means 14 for vertically moving the actuating rod 13. Similarly, the second transfer means 10' comprises several suction grippers 11' for holding the annular frame F, which carries the semiconductor wafer W as the second workpiece, under suction; a transfer arm 12' having a front end on which the suction grippers 11' are located; an actuating rod 13' for vertically moving the transfer arm 12'; and an elevation means 14' for vertically moving the actuating rod 13'. For example, each of the elevation means 14 and 14' is provided by an air piston.In this preferred embodiment, four suction grippers 11 are carried on the transfer arm 12 and four suction grippers 11' are carried on the transfer arm 12'. Each of the suction grippers 11 and 11' is acted upon downwards by a helical spring or the like and connected by a flexible tube to a vacuum distributor (not shown), which is connected to a suction medium (not shown).

[0039] The laser beam application means 5, the cassette table mechanism 7 and 7', the temporary setting means 8 and 8', the handling means 9 and 9' and the transfer means 10 and 10', mentioned above, are mounted on the stationary base 2, as shown in Fig. 1 shown, provided. The actuation of the first laser mechanism 1a including the first clamping table mechanism 3, a part of the application means 5 for the laser beam, the first cassette table mechanism 7, the first temporary setting means 8, the first handling means 9 and the first transfer means 10 is described below with reference to Fig. 1 and Fig. 8-11 described. The operation of the second laser mechanism 1b including the second clamping table mechanism 3', part of the application means 5 for the laser beam, the second cassette table mechanism 7', the second temporary setting means 8', the second handling means 9' and the second transfer means 10' is essentially the same as that of the first laser mechanism 1a and a detailed description thereof is omitted here.

[0040] As in Fig. 1 and Fig. As shown in Figure 8, the first cassette table mechanism 7 is located adjacent to the first clamping table mechanism 3 in the X direction. The first temporary holding device 8 is located directly above the first holding area in which the first workpiece is held or released with respect to the first clamping table 36. The first handling device 9 is located on one side of the first holding area, i.e., on the side opposite the first handling device 9 with respect to the first clamping table mechanism 3.

[0041] The following describes a wafer placement step for taking the semiconductor wafer W as the first workpiece from cassette 70 and then placing the semiconductor wafer W on the first clamping table 36. As in Fig. As shown in Figure 8, the first moving device 82 for the support rails of the first temporary setting device 8 is actuated to move the support rails 81a and 81b relative to each other, thereby reducing the distance between the support rails 81a and 81b according to the outer diameter of the annular frame F, which supports the semiconductor wafer W. Subsequently, the first cassette table 71 is moved vertically to raise the height of the semiconductor wafer W, which is held in the first cassette 70, to the height of the gripping element 92 of the first handling device 9, because the height of the gripping element 92 is fixed.

[0042] After adjusting the height of the semiconductor wafer W, which is held in the first cassette 70, to a height of the gripping element 92, the handling arm 91 is moved towards the first cassette 70 until the gripping element 92 engages with the annular frame F, which supports the semiconductor wafer W held in the first cassette 70. In this state, the gripping element 92 is driven by the air pressure supplied by the air cylinder (not shown) to grip the annular frame F. The movement means 93 for the arm is then actuated to move the handling arm 91 away from the first cassette table mechanism 7, thereby removing the semiconductor wafer W from the first cassette 70 and placing it on the support rails 81a and 81b of the first temporary placement device 8, as shown in Fig. 9 shown, carries. Afterwards, the actuation of the catching element 92, which catches the ring-shaped frame F, is aborted in order to temporarily place the semiconductor wafer W onto the carrier rails 81a and 81b.

[0043] After the semiconductor wafer W has been temporarily placed on the support rails 81a and 81b of the first temporary placement device 8, the lifting device 14 of the first transfer device 10 is actuated to lower the actuating rod 13. As described above, the transfer arm 12, which has the suction grippers 11 at its front end, is connected to the upper end of the actuating arm 13. Accordingly, when the actuating rod 13 is lowered, the suction grippers 11, which are provided at the front end of the transfer arm 12, come into contact with the annular frame F, which supports the semiconductor wafer W that is temporarily placed on the first temporary placement device 8. As described above, each suction gripper 11 is acted upon downwards by a coil spring (not shown), so that when each suction gripper 11 comes into contact with the ring-shaped frame F, each suction gripper 11 is moved slightly upwards relative to the transfer arm 12.When the suction grippers 11 are in contact with the annular frame F, a downward movement of the actuating rod 13 is stopped and a vacuum is supplied to the suction grippers 11 via the vacuum distributor (not shown), whereby a semiconductor wafer W is held by the annular frame F against the suction grippers 11 under suction.

[0044] After the semiconductor wafer W is held by the annular frame F on the suction gripper 11, the movement means 82 for the support rails of the first temporary setting device 8 is actuated to increase the distance between the support rails 81a and 81b to a size greater than the outer diameter of the annular frame, as shown in Fig. 11 shown. The actuating rod 13 is then lowered further to place the semiconductor wafer W on the upper surface of the first clamping table 36, which is positioned in the first holding area. Furthermore, the vacuum supply to the suction gripper 11 is stopped, and the actuating rod 13 is then moved to a retracted position, which is shown in Fig. As shown in Figure 9, the height is increased. Then, the suction device (not shown) is actuated to hold the semiconductor wafer W under suction by the protective band T on the upper surface of the first clamping table 36. Next, the clamps 362 are actuated to hold the annular frame F on the first clamping table 36. Then, the X-movement device 37 of the first clamping table 3 is actuated to move the first clamping table 36 to the first processing area directly below the first focusing device 51 of the application unit 4 for the laser beam.

[0045] Consequently, the wafer placement step was described by the first laser mechanism 1a. As described above, the second laser mechanism 1b has essentially the same configuration as the first laser mechanism 1a, and its actuation is similar to that of the first laser mechanism 1a. That is, the second laser mechanism 1b includes the second clamping table mechanism 3', part of the laser beam delivery device 5, the second cassette table mechanism 7', the second temporary placement device 8', the second handling device 9', and the second transfer device 10'. Accordingly, the description of a wafer placement step by the second laser mechanism 1b is omitted here.The cassette table mechanism 7 and 7', the temporary setting means 8 and 8', the handling means 9 and 9' and the transfer means 10 and 10' are controlled by control signals output from an output port (not shown) included in the control means.

[0046] The following describes one step of the laser processing using the first laser mechanism 1a.

[0047] When the first clamping table 36, which holds the semiconductor wafer W, is positioned in the first processing area, the first imaging means 6 and the control means perform an alignment step of detecting a target area of ​​the semiconductor wafer W to be processed with a laser. That is, the first imaging means 6 and the control means perform image processing such as pattern recognition to align the target lines extending in a first direction on the semiconductor wafer W with the first focusing means 51 of the laser beam delivery means 5 for applying a laser beam along the target line, thereby performing the alignment step of detecting the target lines extending in the first direction.Similarly, this alignment step is performed for the other target lines that extend in a second direction perpendicular to the first direction on the semiconductor wafer W, thereby detecting the target lines that extend in the second direction.

[0048] After performing the alignment step to detect all target lines formed on the semiconductor wafer W, which is held on the first clamping table 36, the first clamping table 36 is moved to a position at the end of a predetermined target line immediately below the first focusing means 51. Then, the focused point of a pulsed laser beam, focused by the focusing lens of the first focusing means 51, is set to a predetermined height in the semiconductor wafer W, the pulsed laser beam having a transmission wavelength suitable for the semiconductor wafer W. The pulsed laser beam is then applied to the semiconductor wafer W by the first focusing means 51, and simultaneously the first clamping table 36 is moved at a predetermined speed in the X direction. Fig. As shown in Figure 1, the first clamping table 36 is moved. When the other end of the predetermined target line reaches the position immediately below the first focusing device 51, the application of the pulsed laser beam is stopped, and the movement of the first clamping table 36 is also stopped. As a result, a modified layer is formed in the semiconductor wafer W along the predetermined target line. After performing such laser processing along the predetermined target line, the Y-movement device 38 is actuated to move the first clamping table 36 in the Y direction, and the laser processing is repeated along all other target lines extending in the first direction. Subsequently, laser processing is performed similarly along all target lines extending in the second direction.One step of the laser processing by the second laser mechanism 1b is essentially the same as in the first laser mechanism 1a described above, so a detailed description of it is omitted here.

[0049] After completion of the laser processing step, the semiconductor wafer W, which is held on the clamping table 36, is returned to its original position in the first cassette 70 in the following procedure, reversed to the wafer placement step, which is related to Fig. described in 8-11, is returned. That is, after processing the semiconductor wafer W in the first processing area, the first clamping table 36, which holds the semiconductor wafer W, is moved from the first processing area to the first holding area, which is described in Fig. As shown in Figure 11, the X-movement device 37 is actuated. The actuating rod 13 of the first transfer device 10 is then lowered until the suction grippers 11 contact the annular frame F, which supports the semiconductor wafer W held on the clamping table 36. A vacuum is then applied to the suction grippers 11 to hold the semiconductor wafer W under suction. The suction holding of the semiconductor wafer W is then released, and the fixed position of the annular frame by the clamps 362 is also released. The actuating rod 13 is then raised to a vertical position higher than the support rails 81a and 81b of the first temporary setting device 8.

[0050] The moving device 82 for the support rails of the first temporary placement device 8 is then actuated to reduce the distance between the support rails 81a and 81b according to the outer diameter of the annular frame F. The actuating rod 13 of the first transfer device 10 is then lowered to place the semiconductor wafer W, held by the suction grippers 11, onto the support rails 81a and 81b, as shown in Fig. 10, to place. Then the vacuum applied to the suction gripper 11 is released, thereby temporarily placing the semiconductor wafer W onto the carrier rails 81a and 81b. After that, the actuating rod 13 is raised to its highest vertical position, i.e., the retracted position shown in Fig. 9 is shown.

[0051] Finally, the handling arm 91 of the first handling device 9 is moved from the position that is in Fig. 9 is shown, to the position that is in Fig. As shown in Figure 8, the semiconductor wafer is moved. At this point, the ring-shaped frame F, which carries the semiconductor wafer, is pressed by the handling arm 91, so that actuation of the catching element 92 is not required. Consequently, the semiconductor wafer W is pressed by the handling arm 91 and thereby returned to its original position in the first cassette 70, as shown in Figure 8. Fig. 8 shown, brought back.

[0052] As in Fig. As shown in Figure 12, the laser processing device 1 includes the laser mechanism 1a and 1b, which is located in Fig. As shown in Figure 1, the housing 200 has a casing for covering the laser mechanism 1a and 1b. The casing 200 has side walls opposite the cassette table mechanism 7 and 7' in the X direction (see Figure 1). Fig. 1) on. This side wall of the housing 200 is provided with a first flap 201 opposite the first cassette table mechanism 7 and a second flap 204 opposite the second cassette table mechanism 7'. The first and second flaps 201 and 204 are arranged parallel in the Y direction. The first and second flaps 201 and 204 are designed as a so-called double flap, such that the first flap 201 is adapted to open to the left, and the second flap 204 is adapted to open to the right, as in Fig. 12. When the first flap 201 is opened, an operator can access the first holding area, which is formed by the first cassette table mechanism 7 of the first laser mechanism 1a and the position in which the workpiece is held or released with respect to the first clamping table 36. Similarly, when the second flap 204 is opened, the operator can reach the second holding area, which is formed by the second cassette table mechanism 7' of the second laser mechanism 1b and the position in which the second workpiece is held or released with respect to the second clamping table 36'. That is, the first and second flaps 201 and 204 are used, respectively, when loading / unloading the first and second cassettes 70 and 70' to / from the first and second cassette tables 71 and 71'.

[0053] The first flap 201 is equipped with a first control panel 202 for actuating the first laser mechanism 1a. Similarly, the second flap 204 is equipped with a second control panel 205 for actuating the second laser mechanism 1b. These control panels 202 and 205 are designed to be operated by a single operator to make various adjustments to the control device. This means that the first laser mechanism 1a and the second laser mechanism 1b can be actuated independently. Accordingly, there is no possibility that, if the first flap 201 is in an open position while loading the first cassette 70 onto the first cassette table 71, the operator would mistakenly actuate the first control panel 202 to start the first laser mechanism 1a.Similarly, there is no possibility that, when the second flap 204 is in an open state to load the second cassette 70' to the second cassette table 71, the operator will mistakenly operate the second control panel 205 to start the second laser mechanism 1b.

[0054] The first control panel 202 is pivotally mounted on the first flap 201, so that it can be moved to the left, as in Fig. 12 can be seen, opened. Similarly, the second control panel 205 is pivotally mounted on the second flap 204 so that it can be opened to the right, as in Fig. 12 can be seen, opened. In the laser processing device 1 according to the preferred embodiment, it is assumed that the operator operates the control panels 202 and 205, confirming the actuations of the laser mechanism 1a and 1b. Accordingly, the left side wall of the housing 200 is provided with a first viewing window 203 to allow the operator to view the first laser mechanism 1a, as shown in Fig.As shown in Figure 12, the right side wall of the housing 200 is similarly provided with a second viewing window 206 to allow the operator to see the second laser mechanism 1b. Accordingly, the operator can operate the first control panel 202 in its open position while viewing the laser mechanism 1a through the first viewing window 203. Similarly, the operator can operate the second control panel 205 in its open position while viewing the second laser mechanism 1b through the second viewing window 206. By providing these viewing windows 203 and 206 and the control panels 202 and 205, there is no possibility that the control panels 202 and 205 will be interchanged when operating the first and second laser mechanisms 1a and 1b.

Claims

[1] Laser processing device (1) for processing semiconductor wafers as workpieces, comprising: a first laser mechanism (1a) comprising a first clamping table (36) for holding a first workpiece, a first X-movement means (37) for moving the first clamping table (36) in an X direction, a first Y-movement means (38) for moving the first clamping table (36) in a Y direction perpendicular to the X direction, and a first focusing means (51) for focusing a first laser beam (LB1) on the first workpiece held on the first clamping table (36); a second laser mechanism (1b) comprising a second clamping table (36') for holding a second workpiece, a second X-movement means (37') for moving the second clamping table in the X direction, a second Y-movement means (38') for moving the second clamping table (36') in the Y direction, and a second focusing means (51') for focusing a second laser beam (LB2) on the second workpiece held on the second clamping table (36'); a laser oscillator for oscillating an original laser beam; an optical system for splitting the original laser beam oscillated by the laser oscillator and guiding the first (LB1) and second laser beams (LB2) respectively to the first (51) and second focusing means (51'); a first control panel (202) for setting a first processing condition for the first laser mechanism (1a); and a second control panel (205) for setting a second processing condition for the second laser mechanism (1b), wherein the first control panel (202) is attached to the laser processing device (1) at a different position than the second control panel (205), wherein the optical system (5) also includes a half-wave plate (53) and a polarization beam splitter (54), the half-wave plate (53) being inserted between the laser oscillator and the polarization beam splitter (54), By rotating the half-wave plate in the original laser beam, the intensity ratio between the first laser beam (LB1) as S-polarized light and the second laser beam (LB2) as P-polarized light, which are emitted by the polarization beam splitter (54), is continuously variable, and In the optical system, a setting agent (57) for a first wavelength and a setting agent (61) for a second wavelength are provided in an optical path of the first laser beam (LB1) and the second laser beam (LB2), which have passed through a first damper (56) and a second damper (60). [2] Laser processing device (1) according to claim 1, further comprising a housing (200) for covering the first laser mechanism (1a) and the second laser mechanism (1b); wherein the housing (200) is provided with a first flap (201) at a position in which the first workpiece is loaded into the first laser mechanism (1a) and a second flap (204) at a position in which the second workpiece is loaded into the second laser mechanism (1b); the first (202) and second control panel (205) are mounted on the first (201) and second flap (204) respectively; the first flap (201) and the second flap (204) are arranged parallel in the Y direction on a plane perpendicular to the X direction. [3] Laser processing device (1) according to claim 2, wherein: the first clamping table (36) is moved by the first X-movement means (37) between a first holding area, at which the first workpiece is held or released with respect to the first clamping table (36), and a first processing area, in which the first laser beam (LB1) is applied by the first focusing means (51) to the first workpiece, which is held at the first clamping table (36); the first holding area includes a first cassette table (71) for mounting a first cassette (70) which receives the first workpiece, a first temporary holding device (8) for temporarily setting down the first workpiece, a first handling device (9) for removing the first workpiece from the first cassette (70) which is mounted on the first cassette table (71), and then carrying the first workpiece to the first temporary holding device (8) and a first transfer device (10) for transferring the first workpiece from the first temporary holding device (8) to the first clamping table (36); the first flap (201) is open when loading / unloading the first cassette (70) to / from the first cassette table (71); and the second clamping table (36') is moved by the second X-movement means (37') between a second holding area, at which the second workpiece is held or released with respect to the second clamping table (36'), and a second processing area, at which the second laser beam (LB2) is applied by the second focusing means (51') to the second workpiece, which is held at the second clamping table (36'); the second holding area includes a second cassette table (71') for mounting a second cassette (70') which holds the second workpiece, a second temporary holding device (8') for temporarily setting down the second workpiece, a second handling device (9') for removing the second workpiece from the second cassette (70') which is mounted on the second cassette table (71'), and then carrying the second workpiece to the second temporary holding device (8') and a second transfer device (10') for transferring the second workpiece from the second temporary holding device (8') to the second clamping table (36'); the second flap (204) is open when loading / unloading the second cassette (70') to / from the second cassette table (71').

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