Laser processing apparatus and processing method

Abstract

To provide a laser processing device and a processing method that can achieve improvement in productivity.SOLUTION: The laser processing device comprises: a laser beam emitting part (12) that emits a laser beam to a process line of a work-piece (W); a relatively moving part (14) that relatively moves the work-piece and the laser beam emitting part; a detecting part that detects a passing of an edge (WB) of the work-piece at a light-condensing position (Lc) of a laser beam during relative movement thereof in a first direction; a movement control part that transmits a command signal that is applied to relative movement from a first process line to a second process line, to the relatively moving part; and a movement start-position calculating part that calculates a movement start-position of the light-condensing position of the laser beam in a second direction at which relative movement in the first direction is started, in processing the second process line. The movement start-position calculating part calculates the movement start-position for each process line, when the light-condensing position of the laser beam reaches the edge through the inside of the work-piece.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus and a processing method.

Background Art

[0002] A laser processing apparatus that irradiates a workpiece with laser light to process the workpiece is known. The laser processing apparatus includes a table that supports the workpiece and a laser light irradiation unit that generates laser light to be irradiated onto the workpiece. The laser processing apparatus relatively moves the workpiece and the laser light irradiation unit in the X-axis direction and the Y-axis direction, and performs processing on the processing line of the workpiece.

[0003] Laser processing apparatuses are desired to have processing control that can improve productivity. In realizing productivity improvement, it is conceivable to relatively increase the moving speed in the X-axis direction, which is the relative moving direction between the laser light and the workpiece during processing. However, when the moving speed is relatively increased, the acceleration period and the deceleration period become relatively long, and productivity improvement is not expected as much. Note that the term "speed" in this specification may include the meaning of the magnitude of the speed.

[0004] Also, it is conceivable to relatively increase the acceleration in the X-axis direction. However, there is a concern that changes in the posture of the stage that supports the workpiece or vibrations of the apparatus may occur, and stable processing quality cannot be obtained. Note that the acceleration here may include the deceleration represented as a negative acceleration.

[0005] Furthermore, when sequentially processing a plurality of processing lines arranged along the Y-axis direction orthogonal to the X-axis direction, it is conceivable to relatively increase the moving speed and acceleration in the movement to the next processing line along the Y-axis direction. However, there is a concern that the period until positioning is completed becomes relatively long due to the occurrence of vibrations of the apparatus or the like.

[0006] Then, it is difficult to improve productivity unless the moving speed and acceleration in the X-axis direction and the Y-axis direction are increased under the condition that changes in the posture of the stage and vibrations of the apparatus do not occur.

[0007] Patent Document 1 describes a laser processing apparatus that performs processing by irradiating a laser beam onto a planned dividing line of a wafer. The apparatus described in the document performs indexing feed using the deceleration period required for stopping the processing feed.

Prior Art Document

Patent Document

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in general processing control, it is necessary to apply a constant moving speed inside the workpiece and scan the laser beam. During the acceleration period from a stop to reaching the moving speed and the deceleration period from the moving speed to a stop, relative movement occurs between the laser beam outside the workpiece and the workpiece.

[0010] Furthermore, when starting the processing, since the processing starts after waiting for the completion of movement in the X-axis direction and the Y-axis direction to the processing start position of each processing line, the processing cannot be started during the period until the completion of movement in the X-axis direction and the Y-axis direction.

[0011] That is, not only the period during which the workpiece is irradiated with the laser beam, but also the relative movement period between the laser beam outside the workpiece and the workpiece and the period of waiting for the completion of movement in the X-axis direction and the Y-axis direction occur, and these periods are factors that impede the improvement of productivity.

[0012] Patent Document 1 does not disclose specific conditions for performing indexing feed using the deceleration period required for stopping the processing feed, such as detection of the wafer, processing feed control, and indexing feed control, when operating the indexing feed using the deceleration period required for stopping the processing feed.

[0013] The present invention has been made in view of such circumstances, and an object thereof is to provide a laser processing apparatus and a processing method capable of improving productivity.

Means for Solving the Problems

[0014] In order to achieve the above object, the following invention aspects are provided.

[0015] The laser processing apparatus according to the first aspect includes a laser light irradiation unit that irradiates laser light onto a processing line of a workpiece set along a second direction orthogonal to a first direction, a plurality of processing lines along the first direction; a relative movement unit that relatively moves the workpiece and the laser light irradiation unit in the first direction and the second direction; a detection unit that detects the passage of the edge of the workpiece at the condensing position of the laser light in the relative movement in the first direction; and a movement control unit that transmits a command signal applied to the relative movement from the first processing line to the second processing line to the relative movement unit based on the detection result of the detection unit. The movement control unit transmits a second direction command to start the relative movement from the first processing line to the second processing line in the second direction to the relative movement unit after the condensing position of the laser light passes from the inside of the workpiece to the first edge of the workpiece in the relative movement in the first direction in the processing of the first processing line, and further transmits a first direction command to complete the relative movement in the first direction in which the condensing position of the laser light moves from the outside of the workpiece to the second edge of the workpiece in the processing of the second processing line to the relative movement unit until the relative movement in the second direction is completed.

[0016] According to the first aspect, when performing the relative movement from the first processing line to the second processing line, the relative movement in the second direction is started before the completion of the relative movement in the first direction, and the relative movement in the first direction is performed during the relative movement in the second direction. Thereby, waiting for the completion of the relative movement in the first direction and waiting for the completion of the relative movement in the second direction do not occur, and an improvement in productivity can be realized.

[0017] The relative movement can be applied to a two-dimensional orthogonal coordinate system with the first direction as the first axis and the second direction as the second axis. As an example of the two-dimensional orthogonal coordinate system, an XY orthogonal coordinate system can be cited.

[0018] The relative movement can be applied to any of the following modes: moving the workpiece relative to the fixed laser beam irradiation unit, moving the laser beam irradiation unit relative to the fixed workpiece, and moving both the laser beam irradiation unit and the workpiece.

[0019] The second mode is the laser processing apparatus of the first mode, and includes a movement start position calculation unit that calculates a movement start position of the condensing position of the laser beam in the second direction where the relative movement in the first direction starts during the processing of the second processing line. When the condensing position of the laser beam reaches the movement start position during the implementation of the relative movement in the second direction, the movement control unit transmits a second direction command for starting the relative movement in the first direction in the processing of the second processing line to the relative movement unit.

[0020] According to the second mode, when the processing of the first processing line is completed and the processing of the second processing line is carried out, when the condensing position of the laser beam reaches the movement start position during the relative movement in the second direction, the relative movement in the first direction can be started.

[0021] The third mode is the laser processing apparatus of the second mode, and the movement start position calculation unit calculates, based on the acceleration, movement speed, and movement distance of the relative movement in the first direction, the period during which the relative movement in the first direction is carried out and the condensing position of the laser beam moves from the first edge to the outside of the workpiece and then moves from the outside of the workpiece to the second edge. Based on the acceleration, movement speed, and movement distance of the relative movement in the second direction, the period during which the relative movement in the second direction is carried out and the condensing position of the laser beam moves from the first processing line to the second processing line is calculated, and the movement start position is calculated using the calculation results.

[0022] According to the third mode, the movement start position can be calculated using the drive control parameters in the first direction and the drive control parameters in the second direction.

[0023] In the fourth aspect, in the laser processing apparatus according to any one of the first to third aspects, the movement control unit performs relative movement in the first direction during the processing of the first processing line, and after the condensing position of the laser beam passes through the first edge of the workpiece from inside the workpiece, a first direction command to stop the relative movement in the first direction at a position outside the workpiece is transmitted to the relative movement unit.

[0024] According to the fourth aspect, during the relative movement in the second direction, the relative movement in the first direction can be stopped, and further, the start of the relative movement in the first direction can be performed.

[0025] In the fifth aspect, in the laser processing apparatus according to any one of the first to fourth aspects, the detection unit includes an encoder that outputs an encoder signal representing the relative movement distance in the relative movement in the first direction, and detects the passage of the condensing position of the laser beam through the edge of the workpiece based on the relative movement distance.

[0026] According to the fifth aspect, in the relative movement from the first processing line to the second processing line, the same positioning accuracy as the relative movement in the first direction when performing the processing on each processing line can be applied.

[0027] In the sixth aspect, in the laser processing apparatus according to any one of the first to fourth aspects, the detection unit includes a sensor that detects the position of the condensing position of the laser beam with respect to the workpiece, and detects the passage of the condensing position of the laser beam through the edge of the workpiece based on the sensor signal output from the sensor.

[0028] According to the sixth aspect, in the detection of the condensing position of the laser beam with respect to the workpiece, the influence of relative conveyance can be suppressed.

[0029] The sensor can apply an optical sensor including a photoelectric conversion element, a photographing device including a photographing element, and the like. The sensor signal can include an image signal representing a photographed image generated using the photographing device.

[0030] In the seventh aspect, in the laser processing apparatus according to any one of the first to sixth aspects, the laser light irradiation unit irradiates each of a plurality of positions separated in a first direction with a plurality of laser lights, the detection unit detects the passage of the edge of the workpiece by the laser light preceding in the first direction, and calculates the distance in the first direction between the condensing positions of the plurality of laser lights from the passage of the edge of the workpiece at the condensing position of the preceding laser light to the passage of the edge of the workpiece at the condensing position of the subsequent laser light, and based on the calculated distance in the first direction between the condensing positions of the plurality of laser lights, detects the passage of the edge of the workpiece by the subsequent laser light.

[0031] According to the seventh aspect, in the aspect of irradiating a plurality of laser lights, based on the distance between the condensing position of the preceding laser light and the condensing position of the subsequent laser light, the condensing position of the subsequent laser light can be grasped from the detection result of the condensing position of the preceding laser light.

[0032] The aspect of irradiating a plurality of laser lights may include any of an aspect including a plurality of laser oscillators and each of the plurality of laser oscillators being provided with a condensing optical system, an aspect including one laser oscillator and an optical element for branching the laser light, and each of the branched laser lights being provided with a condensing optical system.

[0033] The processing method according to the eighth aspect is a processing method for processing a workpiece in which a plurality of processing lines along a first direction are set along a second direction orthogonal to the first direction, and a laser beam irradiating unit that irradiates a laser beam onto the processing lines of the workpiece, and the workpiece is processed by relatively moving the laser beam irradiating unit and the workpiece in the first direction and the second direction. In the relative movement in the first direction, a detection step of detecting the passage of the edge of the workpiece at the condensing position of the laser beam is included. In the relative movement in the first direction in the processing of the first processing line, after the condensing position of the laser beam passes through the first edge of the workpiece from the inside of the workpiece, relative movement in the second direction is performed based on a second direction command for starting the relative movement from the first processing line to the second processing line in the second direction. Further, until the relative movement in the second direction is completed, relative movement in the first direction is performed based on a first direction command for completing the relative movement in the first direction in which the condensing position of the laser beam moves from the outside of the workpiece to the second edge of the workpiece in the processing of the second processing line. The processing method includes a relative movement step.

[0034] According to the eighth aspect, the same effects as those of the first aspect can be obtained.

[0035] In the eighth aspect, the same matters as those specified in the second aspect to the seventh aspect can be appropriately combined. In that case, the components that perform the processes and functions specified in the laser processing apparatus can be grasped as the components of the processing method that perform the corresponding processes and functions.

Advantages of the Invention

[0036] According to the present invention, when performing the relative movement from the first processing line to the second processing line, the relative movement in the second direction is started before the completion of the relative movement in the first direction, and the relative movement in the first direction is performed during the relative movement in the second direction. As a result, waiting for the completion of the relative movement in the first direction and waiting for the completion of the relative movement in the second direction do not occur, and an improvement in productivity can be realized.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

MODE FOR CARRYING OUT THE INVENTION

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification, the same reference numerals are given to the same components, and overlapping descriptions are omitted as appropriate.

[0039] [First Embodiment] [Overall Configuration of Laser Processing Apparatus] FIG. 1 is an overall configuration diagram of a laser processing apparatus according to the embodiment. The laser processing apparatus 10 shown in the figure irradiates laser light along a processing line set in the interior WA of the wafer W, and is a laser dicing apparatus that forms a laser processing region serving as a starting point for cutting in the interior WA of the wafer W along the processing line.

[0040] The laser processing apparatus 10 includes a laser irradiation device 12 and an XY table 14. The laser irradiation device 12 includes a laser oscillator 20 and a condensing optical system 22. The laser irradiation device 12 may sometimes be called a laser engine.

[0041] The laser irradiation device 12 is movably supported in the Z-axis direction using a Z-axis drive unit. The Z-axis drive unit includes a Z-axis drive mechanism and a Z-axis motor. The Z-axis motor includes an encoder. The Z-axis drive unit moves the laser irradiation device 12 in the Z-axis direction to adjust the distance in the Z-axis direction between the laser irradiation device 12 and the wafer W.

[0042] Note that in FIG. 1, the illustration of the Z-axis drive unit is omitted. The Z-axis drive unit is illustrated in FIG. 2 using reference numeral 36. Further, the encoder of the Z-axis motor is illustrated in FIG. 2 using reference numeral 38.

[0043] The laser oscillator 20 outputs a laser beam La. As an example of the laser beam La, a pulsed laser beam with a pulse width of 500 nanoseconds, a peak power density of 1.8×10 8 watts per square centimeter, and a wavelength of 1080 nanometers can be mentioned. The peak power density at the focusing position Lc is an example when the average output is 5.0 watts, the repetition frequency is 200 kilohertz, and the diameter of the laser beam La at the focusing position Lc is 6.0 micrometers. Note that a continuous wave laser beam may be applied as the laser beam La.

[0044] The laser beam La output from the laser oscillator 20 enters the focusing optical system 22. The focusing optical system 22 includes a focusing lens. The focusing lens focuses the laser beam La at the focusing position Lc. The focusing optical system 22 may appropriately include optical members such as an optical filter, a collimating lens, and a mirror. Note that the arrow line shown in FIG. 1 indicates the traveling direction of the laser beam La. The laser irradiation device 12 described in the embodiment corresponds to an example of a laser beam irradiation unit.

[0045] The XY table 14 is attached to the base of the laser processing device 10. The XY table 14 includes an X-axis drive unit 30 and a Y-axis drive unit 32. Note that the illustration of the base of the laser processing device 10 is omitted.

[0046] The X-axis drive unit 30 adsorbs and supports the wafer W on the support surface 34 of the adsorption table 31, and moves the wafer W in the X-axis direction. The X-axis drive unit 30 includes the adsorption table 31, an X-axis drive mechanism, and an X-axis motor. The X-axis motor is equipped with an encoder.

[0047] Note that the illustration of the X-axis drive mechanism and the X-axis motor is omitted. Also, in FIG. 1, the illustration of the encoder of the X-axis motor is omitted. The encoder of the X-axis motor is illustrated in FIG. 2 using the reference numeral 38.

[0048] The adsorption table 31 adsorbs and supports the wafer W on the support surface 34. The adsorption table 31 is connected to the X-axis drive mechanism. The X-axis drive mechanism is connected to the X-axis motor. When the X-axis motor is operated, the wafer W adsorbed and supported on the support surface 34 of the adsorption table 31 moves in the X-axis direction.

[0049] The Y-axis drive unit 32 moves the wafer W adsorbed and supported on the support surface 34 of the adsorption table 31 in the Y-axis direction. The Y-axis drive unit 32 includes a Y-axis drive mechanism and a Y-axis motor. An encoder is attached to the Y-axis motor.

[0050] Note that the illustration of the Y-axis drive mechanism and the Y-axis motor is omitted. Also, in FIG. 1, the illustration of the encoder of the Y-axis motor is omitted. The encoder of the Y-axis motor is illustrated in FIG. 2 using the reference numeral 38. In FIG. 1, the illustration in the Y-axis direction is omitted. The Y-axis direction is the direction penetrating the paper surface of FIG. 1.

[0051] In the present embodiment, an aspect in which the laser irradiation device 12 is supported by using a Z-axis drive unit and the laser irradiation device 12 is moved in the Z-axis direction is illustrated. However, the laser irradiation device 12 may be fixedly supported, and the XY table 14 may be configured as an XYZ table including a Z-axis drive unit, and the wafer W may be moved in the Z-axis direction by using the XYZ table.

[0052] Further, the laser irradiation device 12 may be supported by using the Y-axis drive and the Z-axis drive unit, the laser irradiation device 12 may be moved in the Y-axis direction and the Z-axis direction, and the XY table 14 may be configured as an X table including an X-axis drive unit to move the wafer W in the X-axis direction.

[0053] That is, the X-axis drive unit 30, the Y-axis drive unit 32, and the Z-axis drive unit are configured to enable relative movement between the laser irradiation device 12 and the wafer W in each of the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, the XY table 14 may include a θ-axis drive unit that rotates the wafer W in a plane parallel to the support surface 34 of the suction table 31.

[0054] Note that the X-axis direction described in the embodiment corresponds to an example of the first direction. The Y-axis direction described in the embodiment corresponds to an example of the second direction orthogonal to the first direction. The XY table 14 described in the embodiment corresponds to an example of the relative movement unit.

[0055] 〔Functional Blocks of Laser Processing Apparatus〕 FIG. 2 is a functional block diagram of the laser processing apparatus shown in FIG. 1. The laser processing apparatus 10 includes a control unit 40. The control unit 40 is implemented by a computer. The control unit 40 executes a prescribed program using the hardware described below to realize the functions of the laser processing apparatus 10.

[0056] For the hardware of each part constituting the control unit 40, various processors and various memories can be applied. Examples of the processor include a CPU (Central Processing Unit). The CPU executes a program and functions as various processing units. Examples of the memory include a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0057] The control unit 40 includes an X-axis control unit 42, a Y-axis control unit 44, and a Z-axis control unit 46. The X-axis control unit 42 controls the operation of the X-axis drive unit 30 by applying X-axis control parameters. Also, the X-axis control unit 42 receives an X-axis movement completion signal transmitted from the X-axis drive unit 30. The X-axis movement completion signal indicates the completion of the movement of the X-axis drive unit 30 to a specified position.

[0058] The Y-axis control unit 44 controls the operation of the Y-axis drive unit 32 by applying Y-axis control parameters. Also, the Y-axis control unit 44 receives a Y-axis movement completion signal transmitted from the Y-axis drive unit 32. The Y-axis movement completion signal indicates the completion of the movement of the Y-axis drive unit 32 to a specified position.

[0059] The Z-axis control unit 46 controls the operation of the Z-axis drive unit 36 by applying Z-axis control parameters. Also, the Z-axis control unit 46 receives a Z-axis movement completion signal transmitted from the Z-axis drive unit 36. The Z-axis movement completion signal indicates the completion of the movement of the Z-axis drive unit 36.

[0060] Note that the X-axis control unit 42 and the Y-axis control unit 44 described in the embodiment correspond to examples of the components of the movement control unit.

[0061] The control unit 40 includes a wafer information acquisition unit 50, a processing condition setting unit 52, a coordinate setting unit 54, and a drive control parameter setting unit 56.

[0062] The wafer information acquisition unit 50 acquires wafer information including the position information of the processing lines formed on the wafer W. The wafer information may include information such as the size of the wafer W. The wafer information acquisition unit 50 can acquire the wafer information in the wafer W to be processed via an input interface 58 such as a communication interface.

[0063] The processing condition setting unit 52 sets the processing conditions for the wafer W to be processed based on the wafer information acquired using the wafer information acquisition unit 50. The processing conditions may include conditions of the laser beam La such as the pulse width of the laser beam La.

[0064] The coordinate setting unit 54 sets an XY coordinate system defined on the support surface 34 of the adsorption table 31 for the wafer W to be processed. The coordinate setting unit 54 acquires the coordinate values of three or more edges of the wafer W to be processed, and defines the coordinate values of the center position of the wafer W and the coordinate values of the wafer W edge, etc. The processing line on the wafer W to be processed is represented using the coordinate values of the XY coordinate system defined on the support surface 34 of the adsorption table 31.

[0065] When the laser irradiation device 12 and the wafer W are relatively moved, the condensing position Lc of the laser beam La irradiated from the laser irradiation device 12 is applied with the coordinate values of the XY coordinate system set on the wafer W, and is represented using the X-axis coordinate value and the Y-axis coordinate value.

[0066] The drive control parameter setting unit 56 sets X-axis control parameters, Y-axis control parameters, and Z-axis control parameters based on the wafer information and processing conditions of the wafer W to be processed. The control parameters for each axis may include the acceleration / deceleration speed, moving speed, moving period, moving distance, acceleration period, deceleration period, acceleration distance, constant speed distance, and deceleration distance, etc. Examples of wafer information include the diameter of the wafer W. Examples of processing conditions include the index size.

[0067] For example, an aspect may be adopted in which the acceleration / deceleration speed and the moving speed are set as fixed values, and other parameter values are calculated with reference to the wafer information and processing conditions, etc.

[0068] The drive control parameter setting unit 56 may read out the control parameters for each axis from the control parameter storage unit in which the control parameters for each axis are stored.

[0069] The drive control parameter setting unit 56 transmits the X-axis control parameters to the X-axis control unit 42. Similarly, the drive control parameter setting unit 56 transmits the Y-axis control parameters to the Y-axis control unit 44. The drive control parameter setting unit 56 transmits the Z-axis control parameters to the Z-axis control unit 46.

[0070] The control unit 40 includes a laser irradiation control unit 60. The laser irradiation control unit 60 obtains the conditions of the laser beam La from the processing conditions set using the processing condition setting unit 52, and sets the control parameters of the laser irradiation device 12. The laser irradiation control unit 60 controls the laser irradiation device 12 based on the control parameters.

[0071] During the period when the condensing position Lc of the laser beam La is located inside the wafer W at the internal WA, the laser irradiation control unit 60 turns on the irradiation of the laser beam La, and during the period when the condensing position Lc of the laser beam La is located outside the wafer W, the laser irradiation control unit 60 turns off the irradiation of the laser beam La.

[0072] The laser irradiation control unit 60 may turn on the irradiation of the laser beam La immediately before the condensing position Lc of the laser beam La reaches the edge WB from outside the wafer W, and turn off the irradiation of the laser beam La immediately after the condensing position Lc of the laser beam La reaches the edge WB from inside the wafer W at the internal WA.

[0073] The control unit 40 includes an encoder signal processing unit 70 and a movement parameter calculation unit 72. The encoder signal processing unit 70 obtains the encoder signal output from the encoder 38, and calculates the X-axis coordinate value and the Y-axis coordinate value of the condensing position Lc of the laser beam La based on the encoder signal. The encoder 38 shown in FIG. 2 includes an encoder of the X-axis motor, an encoder of the Y-axis motor, and an encoder of the Z-axis motor.

[0074] Note that the encoder 38 and the encoder signal processing unit 70 described in the embodiment correspond to an example of the components of the detection unit. The encoder 38 described in the embodiment corresponds to an example of an encoder that outputs an encoder signal representing the relative movement distance in the first direction. The X-axis coordinate value and the Y-axis coordinate value of the condensing position Lc of the laser beam La described in the embodiment correspond to an example of the detection result.

[0075] The movement parameter calculation unit 72 calculates the movement parameters applied to the X-axis drive unit 30 and the Y-axis drive unit 32 when moving the wafer W from the processed line where the processing is completed to the next processing target line. Details of the movement parameters will be described later.

[0076] Note that the movement parameter calculation unit 72 described in the embodiment corresponds to an example of a movement start position calculation unit that calculates the movement start position in the second direction of the condensing position of the laser beam when starting relative movement in the first direction.

[0077] The control unit 40 includes a display control unit 80. The display control unit 80 transmits a display signal representing the information to be displayed to the display device 82 using a display device 82 such as a liquid crystal display device. The display device 82 can display wafer information, processing conditions, drive control parameters, and the like.

[0078] The control unit 40 includes an input unit 84. The input unit 84 acquires input information transmitted from the input device 86. The input device 86 can apply input operation members such as a keyboard, a mouse, and a joystick.

[0079] The control unit 40 includes a program storage unit 88. The program storage unit 88 stores programs applied to each part of the laser processing apparatus 10. Each part of the laser processing apparatus 10 reads a program from the program storage unit 88 and realizes the functions of each part.

[0080] 〔Detailed Description of Processing Operation〕 FIG. 3 is a schematic diagram of a processing operation. This figure is a view of the processing target surface of the wafer W as seen from the side of the laser irradiation device 12 shown in FIG. 1. Note that the symbol O represents the origin of the two-dimensional orthogonal coordinate system set in the interior WA of the wafer W. A plurality of processing lines 100 extending in a direction parallel to the X-axis direction are set on the wafer W. The plurality of processing lines 100 are set at a prescribed distance apart in the Y-axis direction.

[0081] The Y-axis drive unit 32 shown in FIG. 2 moves the wafer W in the Y-axis direction to make the Y-axis coordinate value of the condensing position Lc of the laser beam La coincide with the Y-axis coordinate value of each processing line. The X-axis drive unit 30 moves the wafer W in the X-axis direction in a state where the condensing position Lc of the laser beam La in the Y-axis direction is aligned with the position of the processing line. The dashed-dotted arrows indicate the moving directions of the wafer W in the X-axis direction and the Y-axis direction.

[0082] The laser irradiation device 12 irradiates the inside WA of the wafer W with the laser beam La. The X-axis drive unit 30 moves the wafer W in the X-axis direction. In this way, the condensing position Lc of the laser beam La is moved inside the wafer W, and processing for one processing line 100 is performed.

[0083] The movement of the wafer W in the X-axis direction is made at a constant speed during the period when the condensing position Lc of the laser beam La is located inside the wafer W. Also, acceleration is performed during the period when the condensing position Lc of the laser beam La is moving from outside the wafer W toward the inside WA of the wafer W, and deceleration is performed during the period when the condensing position Lc of the laser beam La is moving away from the wafer W outside the wafer W.

[0084] Note that the moving speed of the wafer W may be made constant immediately before the condensing position Lc of the laser beam La reaches the edge WB from outside the wafer W, and deceleration of the wafer W may be started immediately after the condensing position Lc of the laser beam La reaches the edge WB from inside the wafer WA. The periods immediately before and immediately after can be defined based on the conveyance accuracy of the X-axis drive unit 30, the processing accuracy of the wafer W, and the on / off characteristics of the laser oscillator 20.

[0085] Reference numeral 110 shown in FIG. 3 is the locus of the condensing position Lc of the laser beam La in the processing control shown in the present embodiment, and reference numeral 112 is the locus of the condensing position Lc of the laser beam La in the processing control according to the prior art.

[0086] Note that the condensing position Lc of the laser beam La represented by the locus 110 is outside the wafer W where the laser beam La is not actually irradiated, but is the assumed condensing position Lc of the laser beam La when it is assumed that the laser beam La is irradiated. The same applies to the locus 112.

[0087] In the processing control according to the related art, for any processing line 100A, when the condensing position Lc of the laser beam La reaches the edge WB of the wafer W, the deceleration of the wafer W is started, and the movement of the wafer W in the X-axis direction is stopped. The locus 112A represents the locus of the condensing position Lc of the laser beam La during the deceleration period in the movement of the wafer W in the X-axis direction.

[0088] Next, after waiting for the completion of the movement of the wafer W in the X-axis direction, the movement of the wafer W in the X-axis direction and the Y-axis direction to the next processing line 100B is started. The locus 112D and the locus 112B represent the loci of the condensing position Lc of the laser beam La in the X-axis direction and the Y-axis direction, respectively. Further, after waiting for the completion of the movement of the wafer W in the Y-axis direction, the processing of the next processing line 100B is started.

[0089] After the completion of the movement of the wafer W in the Y-axis direction, the movement of the wafer W in the return direction in the X-axis direction is started, and acceleration to a specified speed is performed until the condensing position Lc of the laser beam La reaches the edge WB of the wafer W. The locus 112C represents the locus of the condensing position Lc of the laser beam La during the acceleration period in the movement of the wafer W in the return direction in the X-axis direction.

[0090] On the other hand, in the processing control according to the present embodiment, for the movement in the feed direction in the X-axis direction, when the condensing position Lc of the laser beam La reaches the edge WB of the wafer W, the deceleration in the X-axis direction is started, and the movement of the wafer W in the Y-axis direction is started.

[0091] During the movement of the wafer W in the Y-axis direction, the movement of the wafer W in the X-axis direction is completed, and then the wafer W is moved in the X-axis direction to the position where the movement of the wafer W in the return direction in the X-axis direction is started.

[0092] At that time, the start timing of the movement of the wafer W in the return direction in the X-axis direction is adjusted, and the positioning of the wafer W in the Y-axis direction is completed during the period from the start timing of the movement of the wafer W in the return direction in the X-axis direction with respect to the next processing line 100B to the timing when the condensing position Lc of the laser beam La reaches the edge WB from outside the wafer W.

[0093] Specifically, the Y-axis coordinate value of the condensing position Lc of the laser beam La when starting the movement in the X-axis direction during the movement of the wafer in the Y-axis direction is calculated in advance. When the Y-axis direction coordinate value of the actual condensing position Lc of the laser beam La reaches the calculated Y-axis direction coordinate value, the movement of the wafer W in the X-axis direction is started. Note that during the movement of the wafer in the Y-axis direction described in the embodiment, it corresponds to an example during the implementation of the relative movement in the second direction.

[0094] The Y-axis direction coordinate value of the condensing position Lc of the laser beam La when starting the movement of the wafer W in the return direction in the X-axis direction can be calculated based on the drive control parameter in the X-axis direction and the drive control parameter in the Y-axis direction. The Y-axis direction coordinate value of the condensing position Lc of the laser beam La when starting the movement of the wafer W in the return direction in the X-axis direction is the Y-axis direction coordinate value at the folding position 110A of the locus 110.

[0095] The control example when switching from the movement of the wafer in the feed direction in the X-axis direction to the movement of the wafer in the return direction in the X-axis direction shown in FIG. 3 can be applied to the control when switching from the movement of the wafer in the return direction in the X-axis direction to the movement of the wafer in the feed direction in the X-axis direction.

[0096] Note that the processing line 100A described in the embodiment corresponds to an example of the first processing line. The processing line 100B described in the embodiment corresponds to an example of the second processing line. The edge WB of the processing line 100A described in the embodiment corresponds to an example of the first edge. The edge WB of the processing line 100B described in the embodiment corresponds to an example of the second edge.

[0097] The process of starting the deceleration in the X-axis direction at the timing when the condensing position Lc of the laser beam La described in the embodiment reaches the edge WB of the wafer W corresponds to an example of the process of starting the relative movement from the first processing line to the second processing line in the second direction after the condensing position of the laser beam passes through the first edge of the workpiece from the inside of the workpiece.

[0098] 〔Procedure of the processing method〕 FIG. 4 is a flowchart showing the procedure of the processing method according to the first embodiment. The flowchart shown in FIG. 4 shows the procedure when performing the processing of the processing lines 100A and 100B shown in FIG. 3. Note that in FIG. 4, illustration of the control of the laser irradiation device 12 using the laser irradiation control unit 60 shown in FIG. 2 is omitted.

[0099] In the X-axis machining operation command step S10, the X-axis control unit 42 transmits an X-axis machining operation command to the X-axis drive unit 30. In the X-axis machining operation command step S10, the X-axis control unit 42 sets X-axis control parameters including the acceleration, moving speed, moving distance, etc. applied to the X-axis drive unit 30 for the X-axis drive unit 30.

[0100] In the X-axis movement step S11, the X-axis drive unit 30 receives the X-axis machining operation command transmitted from the X-axis control unit 42. The X-axis drive unit 30 moves the wafer W in the X-axis direction based on the X-axis control parameters. In the X-axis movement step S11, the encoder 38 shown in FIG. 2 outputs an X-axis encoder signal. The X-axis encoder signal is an encoder signal output from the encoder of the X-axis motor. The control unit 40 acquires the X-axis encoder signal.

[0101] In the X-axis coordinate value monitoring step S12, the control unit 40 monitors the X-axis direction coordinate value at which the condensing position Lc of the laser beam La moves from the outside to the inside WA of the wafer W based on the X-axis encoder signal. In the Y-axis movement completion confirmation step S13, the control unit 40 determines whether the Y-axis drive unit 32 has completed positioning to the processing line.

[0102] When the condensing position Lc of the laser beam La moves from the outside to the inside WA of the wafer W and the Y-axis drive unit 32 has completed positioning to the processing line, the processing on the processing line 100A is performed.

[0103] In the X-axis coordinate value monitoring step S14, during the processing on the processing line 100A, the X-axis coordinate value at which the condensing position Lc of the laser beam La moves from the inside WA to the outside of the wafer W is monitored based on the X-axis encoder signal. That is, the control unit 40 monitors the X-axis coordinate value of the condensing position Lc of the laser beam La, and determines whether the X-axis coordinate value of the condensing position Lc of the laser beam La reaches the X-axis coordinate value of the edge WB of the wafer W.

[0104] When the control unit 40 determines that the X-axis coordinate value of the condensing position Lc of the laser beam La does not reach the X-axis coordinate value of the edge WB of the wafer W and is the X-axis coordinate value of the inside WA of the wafer W, the monitoring is continued.

[0105] On the other hand, when it is determined that the X-axis coordinate value of the condensing position Lc of the laser beam La reaches the X-axis coordinate value of the edge WB of the wafer W, the process proceeds to the processing start Y-axis coordinate value calculation step S16.

[0106] In the processing start Y-axis coordinate value calculation step S16, the control unit 40 calculates the X-axis deceleration period, which is the period from the timing when the condensing position Lc of the laser beam La reaches the edge WB of the wafer W to the timing when the movement of the wafer W is stopped, using the acceleration, moving speed, and moving period in the X-axis direction.

[0107] Further, the control unit 40 calculates the X-axis acceleration period, which is the period from the timing when the movement of the wafer W starts in the return direction in the X-axis direction to the timing when the condensing position Lc of the laser beam La reaches the edge WB of the wafer W when processing the next processing line 100B.

[0108] Furthermore, the control unit 40 calculates the Y-axis movement period, which is the movement period between the processing lines in the Y-axis direction, using the acceleration, moving speed, and moving period in the Y-axis direction. Furthermore, the control unit 40 calculates the movement start Y-axis coordinate value, which is the Y-axis coordinate value at which the X-axis drive unit 30 starts moving in the return direction in the X-axis direction.

[0109] In the Y-axis movement command step S18, in the X-axis coordinate value monitoring step S14, when the X-axis coordinate value of the condensing position Lc of the laser beam La matches the X-axis coordinate value of the edge WB of the wafer W, the control unit 40 transmits a Y-axis movement command to the next processing line to the Y-axis drive unit 32. Further, the control unit 40 transmits Y-axis control parameters to the Y-axis drive unit 32. Note that the Y-axis movement command transmitted in the Y-axis movement command step S18 described in the embodiment corresponds to an example of a command signal and a second direction command.

[0110] In the Y-axis movement step S20, the Y-axis drive unit 32 moves the wafer W in the Y-axis direction based on the Y-axis control parameters. The encoder 38 outputs a Y-axis encoder signal when moving the wafer W in the Y-axis direction. The encoder signal processing unit 70 acquires the Y-axis encoder signal. The Y-axis encoder signal is an encoder signal output from the encoder of the Y-axis motor.

[0111] In the X-axis machining start position movement command step S22, when the control unit 40 acquires the X-axis machining operation completion signal transmitted from the X-axis drive unit 30, the control unit 40 transmits an X-axis machining start position movement command representing a movement command to the machining start position of the next processing line to the X-axis drive unit 30. Note that the X-axis machining start position movement command transmitted in the X-axis machining start position movement command step S22 described in the embodiment corresponds to an example of a command signal and a first direction command.

[0112] In the X-axis machining start position movement step S24, the X-axis drive unit 30 decelerates the moving speed of the wafer W in the X-axis direction based on the X-axis control parameters and stops the movement of the wafer W in the X-axis direction. At the timing when the movement of the wafer W in the X-axis direction stops, the X-axis drive unit 30 outputs a machining start position movement completion signal indicating the stop of the movement of the wafer in the X-axis direction. Note that the control unit 40 may determine the stop of the movement of the wafer in the X-axis direction based on the X-axis encoder signal.

[0113] In the Y-axis coordinate value monitoring step S26, the control unit 40 monitors the Y-axis coordinate value of the condensing position Lc of the laser beam La and determines whether or not the Y-axis coordinate value of the condensing position Lc of the laser beam La reaches the movement start Y-axis coordinate value.

[0114] In the Y-axis coordinate value monitoring step S26, when the Y-axis coordinate value of the condensing position Lc of the laser beam La has not reached the movement start Y-axis coordinate value, the control unit 40 continues to monitor the Y-axis coordinate value of the condensing position Lc of the laser beam La. On the other hand, when the Y-axis coordinate value of the condensing position Lc of the laser beam La reaches the movement start Y-axis coordinate value, the process proceeds to the X-axis machining operation command step S28.

[0115] In the X-axis machining operation command step S28, the control unit 40 confirms the acquisition of the machining start position movement completion signal and also confirms the movement of the condensing position Lc of the laser beam La to the movement start Y-axis coordinate value, and transmits an X-axis machining operation command for the machining line 100B shown in FIG. 3. Further, the control unit 40 transmits the X-axis parameters applied to the machining line 100B to the X-axis drive unit 30.

[0116] In the X-axis movement step S30, the control unit 40 operates the X-axis drive unit 30 based on the X-axis parameters to move the wafer W in the return direction in the X-axis direction. Further, the X-axis drive unit 30 outputs an X-axis encoder signal.

[0117] In this way, when the machining of the wafer W on the machining line 100A is completed and the wafer is moved to the position of the next machining line 100B, the movement of the wafer W in the Y-axis direction is started without waiting for the completion of the movement of the wafer W in the feed direction in the X-axis direction, and without waiting for the completion of the movement of the wafer W in the Y-axis direction, the movement of the wafer W in the feed direction in the X-axis direction is started on the next machining line 100B.

[0118] In the machining of the machining line 100B, after starting the movement of the wafer W in the X-axis direction in the X-axis movement step S30, the X-axis coordinate value of the condensing position Lc of the laser beam La is monitored in the X-axis coordinate value monitoring step S32. In the X-axis coordinate value monitoring step S32, the control unit 40 monitors, based on the X-axis encoder signal, whether or not the X-axis coordinate value of the condensing position Lc of the laser beam La has reached the X-axis coordinate value of the edge WB of the wafer W.

[0119] In the X-axis coordinate value monitoring step S32, when the X-axis coordinate value of the condensing position Lc of the laser beam La has not reached the X-axis coordinate value of the edge WB of the wafer W, the control unit 40 continues the X-axis coordinate value monitoring step S32.

[0120] On the other hand, in the X-axis coordinate value monitoring step S32, when the X-axis coordinate value of the condensing position Lc of the laser beam La reaches the X-axis coordinate value of the edge WB of the wafer W, in the Y-axis movement completion confirmation step S34, the control unit 40 checks whether the movement of the wafer W in the Y-axis direction is completed, irradiates the internal WA of the wafer W with the laser beam La, and performs the processing of the processing line 100B. In the processing of the processing line 100B, each step from the X-axis coordinate value monitoring step S14 to the Y-axis movement completion confirmation step S34 is performed. In this way, the processing is sequentially performed for a plurality of processing lines 100, and after the processing for all the processing lines 100 is completed, the processing of the wafer W is terminated.

[0121] In the present embodiment, an aspect is exemplified in which the coordinate value of the condensing position Lc of the laser beam La is grasped based on the encoder signal output from the encoder 38, and the operations of the X-axis driving unit 30 and the Y-axis driving unit 32 are controlled based on the coordinate value of the condensing position Lc of the laser beam La.

[0122] On the other hand, the stop of the X-axis driving unit 30 or the like may be grasped using the sensor signal output from the position sensor provided in the X-axis driving unit 30 or the like. As an example of the sensor signal, an imposition signal of a servo motor provided in the X-axis driving unit 30 or the like can be mentioned. Further, the operation of the X-axis driving unit 30 or the like may be started using a counter value detection function based on the count value of the encoder signal output from the servo motor provided in the X-axis driving unit 30 or the like.

[0123] Note that the X-axis movement step S11, the Y-axis movement step S20, the X-axis processing start position movement step S24, and the X-axis movement step S30 correspond to an example of a relative movement step. The X-axis coordinate value monitoring step S12 and the X-axis coordinate value monitoring step S14 correspond to an example of a detection step.

[0124] [Specific Examples of X - Axis Control Parameters and Y - Axis Control Parameters] Table 1 shows specific examples of X - axis control parameters in any processing line 100A and the next processing line 100B shown in Fig. 3. The X - axis acceleration a x applied when calculating the X - axis control parameters shown in Table 1 is 9800 millimeters per square second, and the X - axis moving speed v x is 300 millimeters per second.

[0125] Also, the diameter of the wafer W is 300 millimeters, the Y - axis coordinate value of any processing line 100A is - 100 millimeters, and the index size is 5.0 millimeters. The origin of the X - axis coordinate and Y - axis coordinate is the center of the wafer W.

[0126]

Table 1

[0127] The moving distance Sx of each processing line 100 is expressed as Sx = s r , the in - wafer moving distance s w and the deceleration distance s f using, Sx = s r + s w + s f . The in - wafer moving distance s w is expressed as s w =(r 2 - y 2 ) 1 / 2 ×2.

[0128] The moving period t t is expressed as t r = t c , the constant - speed period t f and the deceleration period t t using, t r + t c + t f . The acceleration distance s r is s r =(a x ×t r2 ) / 2. The deceleration distance s f is, s f = (a x × t f 2 ) / 2.

[0129] The acceleration period t r is, t r = v x / a x is expressed as. When the acceleration a in the X - axis direction is applied as the deceleration in the X - axis direction x , the deceleration period t in the X - axis direction f is, t f = v x / a x is expressed as. The constant - speed period t c is, t c = (s - s r - s f ) × v x is expressed as.

[0130] [Specific example of calculating the Y - axis direction coordinate value for starting the movement of the wafer in the return direction of the X - axis direction] Table 2 shows a specific example of the movement parameters when calculating the Y - axis direction coordinate value for starting the movement of the wafer in the return direction of the X - axis direction. The calculation of the movement parameters shown in Table 2 applies the acceleration a in the X - axis direction x , the movement speed v in the X - axis direction x as described above. Also, the acceleration a in the Y - axis direction y is 1960 millimeters per square second, and the movement speed v in the Y - axis direction y is 100 millimeters per second.

[0131]

Table 2

[0132] Depending on the magnitude relationship between the total movement period t in the X - axis direction xt and the movement period t in the Y - axis direction yt , the timing for starting the movement of the wafer W in the return direction of the X - axis direction is different, and the Y - axis direction coordinate value for starting the movement of the wafer W in the same direction is different.

[0133] Total movement period t in the X-axis direction xt represents the total movement period in the X-axis direction of the condensing position Lc of the laser beam La from the inside WA of the wafer W to the outside of the wafer W in the previous processing line 100 until the condensing position Lc of the laser beam La moves from the outside of the wafer W to the inside WA of the wafer W in the next processing line 100.

[0134] Total movement period t in the X-axis direction xt is the deceleration period t in the previous processing line 100 xf , the period t during which the condensing position Lc of the laser beam La moves in the X-axis direction to the processing start position of the next processing line 100 xc and the acceleration period t in the X-axis direction in the next processing line 100 xr The sum of. That is, the total movement period t in the X-axis direction xt is t xt =t xf +t xc +t xr as expressed.

[0135] Movement period t in the Y-axis direction yt represents the period during which the condensing position Lc of the laser beam La moves in the Y-axis direction from the previous processing line 100 to the next processing line 100. The movement period t in the Y-axis direction yt is the acceleration period t in the Y-axis direction yr and the deceleration period t in the Y-axis direction yf are included. The movement period t in the Y-axis direction yt may include the constant speed movement period t in the Y-axis direction yc That is, the movement period t in the Y-axis direction yt is t yt =t yr +t yf or t yt =t yr +t yc +t yf as expressed.

[0136] [When the movement period in the Y-axis direction is shorter than the total movement period in the X-axis direction] The total movement period t in the X-axis direction xt is longer than the movement period t in the Y-axis direction ytIf it is short, after the movement in the X-axis direction of the condensing position Lc of the laser beam La to the processing start position of the next processing line 100 is completed, a movement command is given in the return direction in the X-axis direction.

[0137] [When the movement period in the Y-axis direction is longer than the total movement period in the X-axis direction] Total movement period t in the X-axis direction xt Rather than the movement period t in the Y-axis direction yt If it is long, the movement period t in the Y-axis direction yt Subtract the acceleration period t in the X-axis direction from xr The movement start command period t, which is the period obtained I The movement distance ds in the Y-axis direction at y Calculate, and add the calculated movement distance ds in the Y-axis direction to the Y-axis coordinate value of the previous processing line y To calculate the Y-axis direction coordinate value at which the movement of the wafer in the return direction in the X-axis direction starts.

[0138] In such a case, it is distinguished when a movement in the X-axis direction is commanded during acceleration in the Y-axis direction, when a movement in the X-axis direction is commanded during constant-speed movement in the Y-axis direction, and when a movement in the X-axis direction is commanded during deceleration in the Y-axis direction.

[0139] When a movement in the X-axis direction is commanded during acceleration in the Y-axis direction, t I =t yt -t xr The movement start command period t expressed as I Is less than the Y-axis direction acceleration period t yr In such a case, dS y2 =(a y ×t I 2 ) / 2, the movement distance dS in the Y-axis direction expressed as y2 Is added to the Y-axis coordinate value of the previous processing line 100 and calculated. a y Is the acceleration in the Y-axis direction, and the acceleration a in the Y-axis direction y Is a preset fixed value.

[0140] When a movement in the X-axis direction is commanded during constant-speed movement in the Y-axis direction, the movement start command period t Iis the acceleration period t in the Y-axis direction yr or more, and the period t from the start of movement in the Y-axis direction to the start of deceleration yfs is less than.

[0141] In such a case, dS y3 =(a y ×t yr 2 ) / 2 + v y ×(t I - t yr ) represents the moving distance dS in the Y-axis direction y3 is calculated by adding to the Y-axis coordinate value of the previous processing line 100. v y is the speed in the Y-axis direction, and the speed v in the Y-axis direction y is a preset fixed value.

[0142] When movement in the X-axis direction is commanded during deceleration in the Y-axis direction, the movement start command period t I exceeds the period t from the start of movement in the Y-axis direction to the start of deceleration. In such a case, dS yfs =(a y4 ×t y ×t yr 2 ) / 2 + v y ×(t yfs - t yr ) + a y ×(t I - t yfs ) 2 / 2 represents the moving distance dS in the Y-axis direction y4 is calculated by adding to the Y-axis coordinate value of the previous processing line 100. Note that the deceleration in the Y-axis direction is the acceleration a in the Y-axis direction y is set.

[0143] [Effects of the First Embodiment] The laser processing apparatus 10 and the processing method according to the first embodiment can obtain the following effects.

[0144] [1] When the condensing position Lc of the laser beam La reaches the edge of the wafer W from inside the wafer W, the wafer W is moved in the Y-axis direction without waiting for the completion of the movement of the wafer W in the X-axis direction, and the wafer W is moved in the X-axis direction without waiting for the completion of the movement of the wafer W in the Y-axis direction. Thereby, the period from the completion of processing to the start of the next processing can be shortened as compared with the case where the movement in the Y-axis direction is started after the completion of the movement in the X-axis direction and the movement in the X-axis direction is started after the completion of the movement in the Y-axis direction.

[0145] In the specific example shown in Table 2, the period from the completion of processing to the start of the next processing is 0.103 seconds. On the other hand, when waiting for the completion of the movement in the X-axis direction, starting the movement in the Y-axis direction, waiting for the completion of the movement in the Y-axis direction, and starting the movement to the next processing line, the period from the completion of processing to the start of the next processing is 0.162 seconds, and in the illustrated processing line, a shortening of 0.059 seconds is possible.

[0146] 〔2〕 When the condensing position Lc of the laser beam La reaches the edge of the wafer W from inside the wafer WA of the wafer W, the deceleration period and the acceleration period in the X-axis direction are calculated, the movement period in the Y-axis direction is calculated, and the Y-axis coordinate value of the condensing position Lc of the laser beam La when starting the processing in the X-axis direction is calculated. Thereby, movement control in the X-axis direction and the Y-axis direction can be implemented in which the wafer W is moved in the Y-axis direction without waiting for the completion of the movement of the wafer W in the X-axis direction, and the wafer W is moved in the X-axis direction without waiting for the completion of the movement of the wafer W in the Y-axis direction.

[0147] 〔3〕 The coordinate value of the condensing position Lc of the laser beam La is grasped based on the encoder signal output from the encoder 38. Thereby, for the movement between the processing lines, the same positional accuracy as the movement during processing can be realized.

[0148] [Second Embodiment] 〔Overall Configuration of Laser Processing Apparatus〕 FIG. 5 is an overall configuration diagram of a laser processing apparatus according to the second embodiment. In the laser processing apparatus 10A shown in FIG. 5, a sensor 16 is added to the laser processing apparatus 10 shown in FIG. 1. Further, the laser processing apparatus 10A includes a half mirror 24 in the laser irradiation device 12A.

[0149] As the sensor 16, an optical sensor including a photoelectric conversion element 17 such as a photodiode is applied. The sensor 16 is arranged coaxially with the laser beam La on the optical axis, receives the reflected light of the laser beam La irradiated on the wafer W, and outputs a sensor signal corresponding to the reflected light. The sensor signal output from the sensor 16 is transmitted to the control unit. The control unit detects the edge WB of the wafer W based on the sensor signal output from the sensor 16. Note that the sensor 16 described in the embodiment corresponds to an example of a component of the detection unit.

[0150] The half mirror 24 is arranged on the optical path of the laser beam La that has passed through the condensing optical system 22. The half mirror 24 transmits the laser beam La that has passed through the condensing optical system 22 and reflects the reflected light Lb of the laser beam La irradiated on the wafer W toward the sensor 16. Note that the arrow lines shown in FIG. 5 represent the directions of the laser beam La and the reflected light Lb.

[0151] 〔Functional Blocks of Laser Processing Apparatus〕 FIG. 6 is a functional block diagram of the laser processing apparatus shown in FIG. 5. In the control unit 40A shown in FIG. 6, a sensor signal processing unit 71 is added to the control unit 40 shown in FIG. 2. The sensor signal processing unit 71 determines whether or not the condensing position Lc of the laser beam La has moved from the inside WA to the outside of the wafer W based on the sensor signal output from the sensor 16.

[0152] Further, the sensor signal processing unit 71 determines whether or not the condensing position Lc of the laser beam La has moved from the outside to the inside WA of the wafer W based on the sensor signal. That is, the sensor signal processing unit 71 grasps the timing at which the condensing position Lc of the laser beam La reaches the edge WB of the wafer W. Note that the sensor signal processing unit 71 described in the embodiment corresponds to an example of a component of the detection unit.

[0153] Based on the processing result of the sensor signal processing unit 71, the movement parameter calculation unit 72 calculates movement parameters applied to the X-axis drive unit 30 and the Y-axis drive unit 32 when moving the wafer W from the processing line of the processing target to the processing line of the next processing target.

[0154] [Procedure of the processing method] In the processing method according to the second embodiment, in the X-axis coordinate value monitoring step S14 and the X-axis coordinate value monitoring step S32 shown in FIG. 4, instead of monitoring the coordinate value of the condensing position Lc of the laser beam La, monitoring of the sensor signal output from the sensor 16 is performed.

[0155] For example, the timing at which the sensor signal changes rapidly can be grasped as the timing at which the condensing position Lc of the laser beam La reaches the edge WB of the wafer W. In addition, the change in the relative light reception amount of the sensor 16 from a large state to a small state can be grasped as the movement of the condensing position Lc of the laser beam La from the inside WA of the wafer W to the outside. Furthermore, the change in the relative light reception amount of the sensor 16 from a small state to a large state can be grasped as the movement of the condensing position Lc of the laser beam La from the outside of the wafer W to the inside WA.

[0156] In the second embodiment, the encoder signal output from the encoder 38 and the sensor signals of position sensors and the like provided in the X-axis drive unit 30 and the like may be used in combination to grasp the condensing position Lc of the laser beam La.

[0157] The sensor 16 shown in FIG. 5 may be a camera equipped with a CCD (Charge Coupled Device). The control unit 40A can grasp the timing at which the condensing position Lc of the laser beam La reaches the edge WB of the wafer W based on the imaging signal output from the camera.

[0158] In this embodiment, an aspect in which an optical sensor is applied as the sensor 16 is exemplified. However, a displacement sensor may be applied as the sensor 16, and an aspect in which the step between the wafer W and the suction table 31 is detected using the displacement sensor may be implemented.

[0159] [Operation and effect of the second embodiment] The laser processing apparatus 10 and the processing method according to the second embodiment can obtain the following operational effects.

[0160] [1] A sensor 16 is provided coaxially with the optical axis of the laser beam La. Based on the sensor signal output from the sensor 16, it is determined whether or not the condensing position Lc of the laser beam La has reached the edge WB of the wafer W. Thereby, without being affected by the conveyance of the wafer W, the movement control of the wafer W between the processing lines shown in the first embodiment can be performed based on the sensor signal.

[0161] [2] The condensing position Lc of the laser beam La is monitored using the sensor 16 including the photoelectric conversion element 17 or the sensor 16A including the camera 17A. Thereby, the condensing position Lc of the laser beam La can be grasped based on the output signal of the photoelectric conversion element 17 or the camera 17A.

[0162] [First Modification Example] FIG. 7 is an overall configuration diagram of a laser processing apparatus according to the first modification example. The laser processing apparatus 10B shown in FIG. 7 includes a camera 17A having a CCD as the sensor 16A. Further, the laser processing apparatus 10B includes an illumination device 18 that irradiates illumination light Ll to the imaging area of the camera 17A. The half mirror 19 reflects the illumination light Ll toward the half mirror 24. The half mirror 24 reflects the illumination light Ll toward the wafer W.

[0163] At least one of the half mirror 19 and the half mirror 24 may be a dichroic mirror. Note that the illumination device 18 shown in FIG. 7 may be omitted, and the reflected light Lb of the laser beam La may be incident on the camera 17A.

[0164] The illumination light Ll does not have to be incident coaxially with the optical axis of the laser beam La, and may be incident at a position preceding the optical axis of the laser beam La. As an example of the illumination light Ll, halogen illumination and LED illumination can be applied. Note that LED is an abbreviation for Light Emitting Diode.

[0165] In FIG. 7, an arrangement of the camera 17A in which the optical axis of the camera 17A is coaxial with the optical axis of the laser beam La is illustrated. However, the camera 17A may be arranged at a position other than being coaxial with the optical axis of the laser beam. The camera 17A may be an omnidirectional camera whose imaging field includes the entire wafer W, and an arrangement of the camera 17A in which the entire wafer W is included in the field of view may be applied. In such an aspect, the wafer W during movement and during stop may be continuously imaged, and the size of the wafer W and the center position of the wafer W in the captured image may be read from the wafer information, and the inside WA and the outside of the wafer W may be calculated.

[0166] According to the first modification example, the condensing position Lc of the laser beam La can be grasped based on the captured image of the wafer W obtained from the camera 17A or the like.

[0167] [Second Modification Example] FIG. 8 is an overall configuration diagram of a laser processing apparatus according to the second modification example. The laser processing apparatus 10C shown in FIG. 8 includes a first laser irradiation device 12B and a second laser irradiation device 12C. The first laser irradiation device 12B may adopt the same configuration as the laser irradiation device 12A shown in FIG. 5. The second laser irradiation device 12C may adopt the same configuration as the laser irradiation device 12 shown in FIG. 1 or the like.

[0168] The first laser irradiation device 12B irradiates the wafer W with a first laser beam La1. The second laser irradiation device 12C irradiates the wafer W with a second laser beam La2.

[0169] The sensor 16 receives the reflected light Lb reflected by using the half mirror 24 provided in the first laser irradiation device 12B. The control unit 40A shown in FIG. 6 grasps the timing when the condensing position Lc1 of the first laser beam La1 reaches the edge WB of the wafer W and the timing when the condensing position Lc2 of the second laser beam La2 reaches the edge WB of the wafer W based on the sensor signal output from the sensor 16.

[0170] That is, the position where the edge WB of the wafer W is offset by the distance between the condensing position Lc1 of the first laser beam La1 and the condensing position Lc2 of the subsequent second laser beam La2 is regarded as the provisional edge WD of the wafer W. The wafer W illustrated by the two-dot chain line in FIG. 8 schematically shows the provisional edge WD of the wafer W.

[0171] Using the distance from the edge WB of the wafer W to the provisional edge WD of the wafer W and the conveyance speed of the wafer W, the period from the timing when the condensing position Lc1 of the first laser beam La1 reaches the edge WB of the wafer W to the timing when the condensing position Lc2 of the second laser beam La2 reaches the edge WB of the wafer W is calculated.

[0172] In this way, based on the timing when the condensing position Lc1 of the first laser beam La1 reaches the edge WB of the wafer W, the timing when the condensing position Lc2 of the second laser beam La2 reaches the edge WB of the wafer W can be grasped.

[0173] The sensor 16 shown in FIG. 8 may be the sensor 16A shown in FIG. 7, or a sensor including a wide-angle camera in which the entire wafer W is included in the imaging field of view may be applied.

[0174] When moving the wafer W in the return direction, the positions of the first laser irradiation device 12B and the second laser irradiation device 12C may be interchanged with respect to the case of moving the wafer W in the feed direction, or the processing may not be performed when moving the wafer W in the return direction.

[0175] A sensor 16 for detecting the reflected light of the first laser beam La1 and a sensor for detecting the reflected light of the second laser beam La2 may be provided, and the timing when the condensing position Lc1 of the first laser beam La1 reaches the edge WB of the wafer W and the timing when the condensing position Lc2 of the second laser beam La2 reaches the edge WB of the wafer W may be individually detected.

[0176] The processing method according to the second modification example is also applicable to a configuration in which a plurality of laser beams are output from one laser irradiation device. As a configuration for outputting a plurality of laser beams from one laser irradiation device, an example is a case where the laser beam output from one laser oscillator is incident on a plurality of condenser optical systems, and the laser beam is irradiated from each of the plurality of condenser optical systems.

[0177] According to the second modification example, even in a mode in which a plurality of condenser optical systems are provided and the laser beam La is output from each of the plurality of condenser optical systems, the wafer W movement control between the processing lines shown in the first embodiment can be implemented.

[0178] Note that the first laser irradiation device 12B and the second laser irradiation device 12C described in the embodiment correspond to an example of a laser beam irradiation unit that irradiates a plurality of laser beams to each of a plurality of positions separated in the first direction.

[0179] In the first embodiment and the second embodiment, the dicing device that processes the wafer W is exemplified as the laser processing device 10, but it can be applied to a laser processing device that processes metals, ceramics, etc. Further, the laser processing shown in the first embodiment and the second embodiment is applicable to both the surface processing of the workpiece such as ablation and the formation of the laser processing region inside the workpiece.

[0180] The embodiments of the present invention described above can be appropriately changed, added, or deleted in terms of configuration requirements without departing from the gist of the present invention. The present invention is not limited to the embodiments described above, and many modifications are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

Explanation of Reference Numerals

[0181] 10, 10A, 10B, 10C… Laser processing apparatus, 12, 12A… Laser irradiation apparatus, 12B… First laser irradiation apparatus, 12C… Second laser irradiation apparatus, 14… XY table, 16… Sensor, 30… X-axis drive unit, 31… Adsorption table, 32… Y-axis drive unit, 38… Encoder, 40… Control unit, 42… X-axis control unit, 44… Y-axis control unit, 70… Encoder signal processing unit, 71… Sensor signal processing unit, 72… Movement parameter calculation unit, 100, 100A, 100B… Processing line, La… Laser light, Lc… Focus position, W… Wafer, WB… Edge

Claims

1. A laser light irradiation unit that irradiates laser light onto a processing line of a workpiece, where a plurality of processing lines along a first direction are set along a second direction orthogonal to the first direction; A relative movement unit that relatively moves the workpiece and the laser light irradiation unit in the first direction and the second direction; A detection unit that detects the passage of the edge of the workpiece at the condensing position of the laser light during the relative movement in the first direction; A movement control unit that transmits a command signal applied to the relative movement from a first processing line to a second processing line to the relative movement unit based on the detection result of the detection unit; A movement start position calculation unit that calculates a movement start position of the condensing position of the laser light in the second direction at which the relative movement in the first direction starts during the processing of the second processing line; comprising; The movement start position calculation unit calculates the movement start position for each processing line when the condensing position of the laser light reaches the edge from the inside of the workpiece, and the laser processing apparatus.

2. The movement start position calculation unit calculates, based on the acceleration, movement speed, and movement distance of the relative movement in the first direction, a period during which the relative movement in the first direction is performed and the condensing position of the laser light moves from a first edge of the workpiece to the outside of the workpiece and then moves from the outside of the workpiece to a second edge of the workpiece. The movement start position calculation unit also calculates, based on the acceleration, movement speed, and movement distance of the relative movement in the second direction, a period during which the relative movement in the second direction is performed and the condensing position of the laser light moves from the first processing line to the second processing line. The movement start position is calculated using the results of the calculations. The laser processing apparatus according to claim 1.

3. The detection unit includes an encoder that outputs an encoder signal representing the relative movement distance in the relative movement in the first direction, The laser processing apparatus according to claim 1 or 2, wherein the passage of the edge of the workpiece at the condensing position of the laser light is detected based on the relative movement distance.

4. The detection unit includes a sensor that detects the position of the condensing position of the laser light with respect to the workpiece, and the laser processing apparatus according to any one of claims 1 to 3, wherein the passage of the edge of the workpiece at the condensing position of the laser light is detected based on a sensor signal output from the sensor.

5. The laser light irradiation unit irradiates a plurality of laser lights at respective positions spaced apart in the first direction. The detection unit identifies the condensing position of a subsequent laser light in the first direction when detecting the passage of the edge of the workpiece by a preceding laser light, calculates a period from the passage of the edge of the workpiece by the preceding laser light to the passage of the edge of the workpiece by the subsequent laser light based on the distance from the edge of the workpiece to the condensing position of the subsequent laser light thus identified and the relative speed between the workpiece and the irradiation position of the subsequent laser light, The laser processing apparatus according to any one of claims 1 to 4, which detects the passage of the edge of the workpiece by the subsequent laser light based on the calculated period.

6. A processing method for processing a workpiece, in which a plurality of processing lines along a first direction are set along a second direction orthogonal to the first direction, and a laser light irradiation unit that irradiates laser light to the processing lines of the workpiece are relatively moved in the first direction and the second direction, the method comprising: a detection step of detecting the passage of the edge of the workpiece by the condensing position of the laser light in the relative movement in the first direction; a relative movement step of performing the relative movement based on a command signal applied to the relative movement from a first processing line to a second processing line based on a detection result in the detection step; a movement start position calculation step of calculating a movement start position of the condensing position of the laser light in the second direction at which the relative movement in the first direction is started during the processing of the second processing line, and a movement start position calculation step of calculating the movement start position for each processing line when the condensing position of the laser light reaches the edge from inside the workpiece; A processing method including the above.

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