JP2016010809A - Laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device having a function of detecting a degree of contamination of a condensing object lens.SOLUTION: A laser processing device comprises: workpiece holding means for holding a workpiece; laser beam irradiation means for laser-processing the workpiece held by the workpiece holding means; and processing feed means for moving the workpiece holding means and the laser beam irradiation means relatively in a processing feed direction. The laser beam irradiation means includes: laser beam oscillation means for generating a laser beam; and a condenser comprising a condensing object lens for condensing the laser beam generated from the laser beam oscillation means and irradiating the workpiece held by the workpiece holding means with the laser beam. The laser processing device also comprises: condensing object lens contamination detection means for detecting a degree of contamination of the condensing object lens; and alarm means for warning if the degree of contamination of the condensing object lens, which has been detected by the condensing object lens contamination detection means, exceeds an allowable value.

Description

  The present invention relates to a laser processing apparatus that performs laser processing on a workpiece such as a semiconductor wafer.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by division lines arranged in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and devices such as ICs and LSIs are formed in the partitioned regions. . Then, the semiconductor wafer is cut along the planned division line to divide the region where the device is formed to manufacture individual semiconductor devices. In addition, an optical device wafer in which a light receiving element such as a photodiode or a light emitting element such as a laser diode is laminated on the surface of a sapphire substrate is also cut along a planned division line, thereby individual optical devices such as photodiodes and laser diodes And is widely used in electrical equipment.

  As a method of dividing a wafer such as the above-described semiconductor wafer or optical device wafer along the planned division line, laser processing is performed by irradiating the wafer with a laser beam having a wavelength that has absorptivity to the wafer along the planned division line. A method has been proposed in which a groove is formed and the wafer is broken along a predetermined dividing line in which a laser processed groove is formed. A laser processing apparatus for performing such laser processing includes a workpiece holding means for holding a workpiece, a laser beam irradiation means for laser processing the workpiece held by the workpiece holding means, and the workpiece Processing holding means for relatively moving the holding means and the laser beam irradiation means in the processing feeding direction is provided. The laser beam irradiating means includes a laser beam oscillating means for oscillating a laser beam, and a condensing objective lens for condensing the laser beam oscillated from the laser beam oscillating means and irradiating the workpiece held by the workpiece holding means. And a concentrator provided.

However, when a laser beam is irradiated along the planned dividing line of a wafer such as silicon or sapphire, the silicon or sapphire is melted and molten debris or debris is scattered to contaminate the condenser objective lens. However, there is a problem that the output of the laser beam applied to the workpiece is lowered and the processing quality is not stable.
Further, when the condensing objective lens is contaminated by debris, there is a problem in that the laser beam oscillated from the laser beam oscillating means is absorbed by the condensing objective lens contaminated by debris and the condensing objective lens is damaged.

  In order to solve the above-described problem, a laser processing apparatus including a suction unit that sucks dust such as debris generated by irradiating a workpiece with a laser beam from a condenser of the laser beam irradiation unit has been proposed. (For example, refer to Patent Document 1).

JP 2007-69249 A

Thus, it is difficult to prevent the condenser objective lens from being contaminated by dust such as debris even in the laser beam irradiation means provided with the suction means for sucking dust such as debris.
Therefore, when the condenser objective lens is contaminated by dust such as debris, it is important that the timing for cleaning the condenser objective lens or the timing for replacing the condenser objective lens can be detected.

  The present invention has been made in view of the above-mentioned facts, and a main technical problem thereof is to provide a laser processing apparatus having a function capable of detecting the degree of contamination of a condenser objective lens.

In order to solve the above-mentioned main technical problem, according to the present invention, a workpiece holding means for holding a workpiece, and a laser beam irradiation means for laser processing the workpiece held by the workpiece holding means, A workpiece feeding means for moving the workpiece holding means and the laser beam irradiation means relative to the machining feed direction, the laser beam irradiation means comprising: a laser beam oscillation means for oscillating a laser beam; and the laser beam oscillation means. A laser processing apparatus including a condenser having a condenser objective lens that condenses an oscillated laser beam and irradiates the workpiece held by the workpiece holding means,
Condensing objective lens contamination detecting means for detecting the degree of contamination of the condensing objective lens, and an alarm when the degree of contamination of the condensing objective lens detected by the condensing objective lens contamination detecting means exceeds an allowable value Alarm means,
A laser processing apparatus is provided.

The condensing objective lens contamination detecting means includes an output detector that is disposed adjacent to the workpiece holding means and detects an output of a laser beam irradiated from the condenser, and an output detected by the output detector is predetermined. Control means for determining whether or not the value is equal to or less than a value and outputting an alarm signal to the alarm means when the output detected by the output detector is equal to or less than a predetermined value.
Further, the condensing objective lens contamination detection means can be moved back and forth between the working laser beam oscillator for oscillating the inspection laser beam and the path connecting the laser beam oscillating means of the workpiece holding means and the condenser. The direction changing means for changing the direction of the inspection laser beam oscillated from the inspection laser beam oscillator toward the condenser in the state of being disposed at the operating position, the direction changing means oscillated from the inspection laser beam oscillator, and A beam splitter for branching the reflected light of the inspection laser beam irradiated to the workpiece holding means via the condenser to the reflected light detection path, and the intensity of the reflected light branched to the reflected light detection path by the beam splitter. A photo detector to be detected and whether or not the intensity of the reflected light detected by the photo detector is equal to or lower than a predetermined value are determined. Intensity of the reflected light Tekuta is detected and a control means for outputting an alarm signal to the alarm means when the predetermined value or less.

  According to the laser processing apparatus of the present invention, the condenser objective lens contamination detecting means for detecting the degree of contamination of the condenser objective lens, and the degree of contamination of the condenser objective lens detected by the condenser objective lens contamination detector is acceptable. Since the alarm means for warning when the value is exceeded, the operator knows the timing to clean or replace the condenser objective lens, and the output of the laser beam irradiated to the work piece is reduced to stabilize the processing quality And the problem that the condenser objective lens is damaged when the condenser objective lens is contaminated by debris can be solved.

The perspective view of the laser processing apparatus comprised according to this invention. The block block diagram of the laser beam irradiation means with which the laser processing apparatus shown in FIG. 1 is equipped. The block block diagram of the control means with which the laser processing apparatus shown in FIG. 1 is equipped. The block block diagram which shows other embodiment of a condensing objective-lens contamination detection means.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer processing method and a laser processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a laser processing apparatus constructed according to the present invention. A laser processing apparatus shown in FIG. 1 includes a stationary base 2 and a chuck table mechanism 3 that is disposed on the stationary base 2 so as to be movable in a machining feed direction (X-axis direction) indicated by an arrow X and holds a workpiece. And a laser beam irradiation unit 4 as a laser beam irradiation means disposed on the base 2.

  The chuck table mechanism 3 includes a pair of guide rails 31 and 31 disposed in parallel along the X-axis direction on the stationary base 2, and is arranged on the guide rails 31 and 31 so as to be movable in the X-axis direction. A first slide block 32 provided, and a second slide arranged on the first slide block 32 so as to be movable in an index feed direction (Y-axis direction) indicated by an arrow Y orthogonal to the X-axis direction. A block 33, a support table 35 supported by a cylindrical member 34 on the second sliding block 33, and a chuck table 36 as a workpiece holding means are provided. The chuck table 36 includes a suction chuck 361 made of a porous material, and holds, for example, a circular semiconductor wafer as a workpiece on a holding surface which is the upper surface of the suction chuck 361 by suction means (not shown). It is supposed to be. The chuck table 36 configured as described above is rotated by a pulse motor (not shown) disposed in the cylindrical member 34. The chuck table 36 is provided with a clamp 362 for fixing an annular frame that supports a workpiece such as a semiconductor wafer via a protective tape.

  The first sliding block 32 has a pair of guided grooves 321 and 321 fitted to the pair of guide rails 31 and 31 on the lower surface thereof, and is parallel to the upper surface along the Y-axis direction. A pair of formed guide rails 322 and 322 are provided. The first sliding block 32 configured in this manner moves in the X-axis direction along the pair of guide rails 31, 31 when the guided grooves 321, 321 are fitted into the pair of guide rails 31, 31. Configured to be possible. The chuck table mechanism 3 in the illustrated embodiment includes a processing feed means 37 for moving the first slide block 32 along the pair of guide rails 31, 31 in the X-axis direction. The processing feed means 37 includes a male screw rod 371 disposed in parallel between the pair of guide rails 31 and 31, and a drive source such as a pulse motor 372 for rotationally driving the male screw rod 371. One end of the male screw rod 371 is rotatably supported by a bearing block 373 fixed to the stationary base 2, and the other end is connected to the output shaft of the pulse motor 372 by transmission. The male screw rod 371 is screwed into a penetrating female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the first sliding block 32. Therefore, the first slide block 32 is moved in the X-axis direction along the guide rails 31 and 31 by driving the male screw rod 371 forward and backward by the pulse motor 372.

  The second sliding block 33 is provided with a pair of guided grooves 331 and 331 which are fitted to a pair of guide rails 322 and 322 provided on the upper surface of the first sliding block 32 on the lower surface thereof. By fitting the guided grooves 331 and 331 to the pair of guide rails 322 and 322, the guided grooves 331 and 331 are configured to be movable in the Y-axis direction. The chuck table mechanism 3 in the illustrated embodiment includes an index feeding means 38 for moving the second sliding block 33 in the Y-axis direction along a pair of guide rails 322 and 322 provided on the first sliding block 32. It has. The index feeding means 38 includes a male screw rod 381 disposed in parallel between the pair of guide rails 322 and 322, and a drive source such as a pulse motor 382 for rotationally driving the male screw rod 381. One end of the male screw rod 381 is rotatably supported by a bearing block 383 fixed to the upper surface of the first sliding block 32, and the other end is connected to the output shaft of the pulse motor 382. The male screw rod 381 is screwed into a penetrating female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the second sliding block 33. Therefore, by driving the male screw rod 381 forward and backward by the pulse motor 382, the second slide block 33 is moved along the guide rails 322 and 322 in the Y-axis direction.

  The laser beam irradiation unit 4 includes a support member 41 disposed on the base 2, a casing 42 supported by the support member 41 and extending substantially horizontally, and a laser beam irradiation disposed on the casing 42. Means 5 and imaging means 6 that is disposed at the front end of the casing 42 and detects a processing region to be laser processed are provided. In addition, in the illustrated embodiment, the imaging unit 6 is irradiated with an infrared illumination unit that irradiates a workpiece with infrared rays, in addition to a normal imaging device (CCD) that captures an image with visible light, and the infrared illumination unit. An optical system that captures infrared light and an image sensor (infrared CCD) that outputs an electrical signal corresponding to the infrared light captured by the optical system, and the like, send the captured image signal to a control means described later.

The laser beam irradiation means 5 will be described with reference to FIG.
The laser beam irradiation means 5 shown in FIG. 2 has a pulse laser beam oscillation means 51, an output adjustment means 52 for adjusting the output of the pulse laser beam oscillated by the pulse laser beam oscillation means 51, and the output adjusted by the output adjustment means 52. And a condenser 53 for condensing the pulsed laser beam and irradiating the workpiece W held on the chuck table 36. The pulse laser beam oscillating means 51 includes a pulse laser beam oscillator 511 composed of a YAG laser oscillator, and a repetition frequency setting means 512 attached thereto. The output adjustment unit 52 adjusts the output of the pulse laser beam LB1 oscillated by the pulse laser beam oscillation unit 51. The condenser 53 includes a direction changing mirror 531 for changing the direction of the pulse laser beam LB1 oscillated from the pulse laser beam oscillating means 51 and adjusted in output by the output adjusting means 52 toward the holding surface of the chuck table 36, and the direction changing mirror. And a condensing objective lens 532 that condenses the pulsed laser beam LB1 whose direction has been changed by 531 and irradiates the workpiece W held on the chuck table 36. The concentrator 53 thus configured is attached to the tip of the casing 42 as shown in FIG.

  1 and 2, the support table 35 constituting the chuck table mechanism 3 is disposed adjacent to the chuck table 36 serving as a workpiece holding means, and the condensing objective lens 532 described above. An output detector 71 for detecting the output of the laser beam emitted from the condenser 53 constituting the condenser objective lens contamination detection means 7 for detecting the degree of contamination is provided. This output detector 71 sends the output of the received laser beam to the control means described later.

  The laser processing apparatus in the illustrated embodiment includes the control means 8 shown in FIG. The control means 8 is constituted by a computer, and a central processing unit (CPU) 81 that performs arithmetic processing according to a control program, a read-only memory (ROM) 82 that stores a control program and the like, and a readable and writable memory that stores arithmetic results and the like. A random access memory (RAM) 83, an input interface 84 and an output interface 85 are provided. Detection signals from the imaging means 6, the output detector 71, and the like are input to the input interface 84 of the control means 8. A control signal is output from the output interface 85 of the control means 6 to the processing feed means 37, the index feed means 38, the pulse laser beam oscillation means 51, the output adjustment means 52, the display means 80 as an alarm means, and the like.

The laser processing apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
The output adjusting means 52 adjusts the output of the pulsed laser beam LB1 having a wavelength (for example, the wavelength is 355 nm) having an absorptivity with respect to the workpiece oscillated from the pulse laser beam oscillating means 51 of the laser beam irradiating means 5 described above. By irradiating the workpiece W held on the chuck table 36 via the device 53, when the workpiece W is ablated, debris is scattered and the condenser objective lens 532 is contaminated. Further, the output adjusting means 52 adjusts the output of the pulse laser beam LB1 having a wavelength (for example, the wavelength is 1064 nm) having transparency to the workpiece oscillated from the pulse laser beam oscillating means 51 and adjusts the output through the condenser 53. By irradiating the work piece W held on the chuck table 36 with a condensing point positioned, fine dust is scattered even if an internal process for forming a modified layer is performed inside the work piece W. As a result, the condenser objective lens 532 is contaminated. When the degree of contamination of such a condenser objective lens 532 exceeds an allowable value, there is a problem that the output of the pulse laser beam LB1 irradiated to the workpiece W is lowered and the processing quality is not stabilized as described above. In addition, there is a problem that the pulsed laser beam LB1 oscillated from the pulsed laser beam oscillating means 51 is absorbed by the condenser objective lens 532 contaminated by debris and the condenser objective lens 532 is damaged. Therefore, it is important to periodically detect the degree of contamination of the condenser objective lens 532 and confirm the degree of contamination of the current condenser objective lens 532 in advance.

Hereinafter, a procedure for detecting the degree of contamination of the condenser objective lens 532 will be described.
First, the control means 8 operates the processing feed means 37 and the index feed means 38 to position the output detector 71 disposed on the support table 35 constituting the chuck table mechanism 3 immediately below the condenser objective lens 532. . Next, the control means 8 operates the pulse laser beam oscillation means 51 to oscillate the pulse laser beam LB1, and controls the output adjustment means 52 to output the output of the pulse laser beam LB1 oscillated from the pulse laser beam oscillation means 51, for example, 2W. Adjust to. As a result, the pulsed laser beam LB1 adjusted to 2 W is applied to the output detector 71 via the condenser objective lens 532 of the condenser 53. The output detector 71 irradiated with the pulse laser beam LB1 in this way sends a signal corresponding to the output of the received pulse laser beam LB1 to the control means 8.

  The control means 8 indicates that the signal (A) corresponding to the output of the pulse laser beam sent from the output detector 71 exceeds the permissible value of the degree of contamination of the condenser objective lens 532 (for example, 10% of the set output). It is determined whether or not. In the illustrated embodiment, since the output of the pulse laser beam sent from the output detector 7 is 2 W, the allowable value of the degree of contamination is 0.2 W. Therefore, the control means 8 is such that the signal (A) corresponding to the output of the pulse laser beam detected by the output detector 71 is a value obtained by subtracting the allowable value 0.2W from the set output (2W) (2W-0). .. 2 W = 1.8 W) or more (A ≧ 1.8 W), it is within the allowable value (0.2 W) of the degree of contamination of the condenser objective lens 532 and it is determined that it can be used. Then, the control means 8 displays the determination result on the display means 80 as an alarm means together with the signal (A) value corresponding to the output of the pulse laser beam LB1 detected by the output detector 71.

  On the other hand, the signal (A) corresponding to the output of the pulse laser beam LB1 detected by the output detector 71 is a value obtained by subtracting the allowable value 0.2W from the set output (2W) (2W−0.2W = If it is less than 1.8W) (A <1.8W), the control means 8 determines that the allowable value (0.2W) of the degree of contamination of the condenser objective lens 532 is exceeded and outputs the determination result. A signal (A) value corresponding to the output of the pulse laser beam LB1 detected by the detector 71 is displayed on the display means 80 as an alarm means. Thus, based on the determination result displayed on the display unit 80 as the alarm unit and the signal (A) value corresponding to the output of the pulsed laser beam LB1 detected by the output detector 71, the operator condenses the objective lens 532. Consider cleaning or replacing. In addition, when it determines with exceeding the tolerance | permissible value (0.2W) of the contamination degree of the condensing objective lens 532, you may make it alarm by operating an alarm buzzer or an alarm lamp.

Next, another embodiment of the condensing objective lens contamination detection means for detecting the degree of contamination of the condensing objective lens 532 will be described with reference to FIG.
Condensing objective lens contamination detection means 7 a for detecting the degree of contamination of the condenser objective lens 532 shown in FIG. 4 is disposed in the laser beam irradiation means 5. That is, the condensing objective lens contamination detection means 7a shown in FIG. The inspection laser beam oscillated from the inspection laser beam oscillator 72 is collected in a state in which it is disposed in the path between the lens 532 so as to be able to advance and retreat to the retracted position indicated by the two-dot chain line and the retracted position indicated by the solid line. Irradiating to the chuck table 36 as the workpiece irradiating means via the direction changing means 73 and the focusing objective lens 532 oscillated from the inspection laser beam oscillator 72 and the direction changing means 73 for changing the direction toward the optical objective lens 532. A beam splitter 75 for branching the reflected light of the inspection laser beam LB2 to the reflected light detection path 74; A condensing lens 76 disposed in the light detection path 74, and a photo detector 77 when detecting the light intensity of the reflected light branched to the reflected light detection path 74 by the beam splitter 75 and collected by the condensing lens 76, It has.

  The inspection laser beam oscillator 72 outputs, for example, a He-Ne laser having a wavelength of 632 nm and an output of 2 mW, or an SLD laser having a wavelength of 830 nm and an output of 3 mW. The direction changing means 73 includes a direction changing mirror 731 and an actuator 732 that moves the direction changing mirror 731 to move to a retracted position indicated by a solid line and an operating position indicated by a two-dot chain line in FIG. That is, the actuator 732 of the direction changing means 73 positions the direction changing mirror 731 at the retracted position indicated by a solid line when performing the laser processing operation by the laser beam irradiation means 5, and the degree of contamination of the condensing objective lens 532 Is detected, the direction change mirror 731 is positioned at the action position indicated by the two-dot chain line. The beam splitter 75 passes the inspection laser beam LB2 oscillated from the inspection laser beam oscillator 72 toward the direction changing mirror 731. The reflected light of the inspection laser beam LB2 irradiated on the chuck table 36 is reflected light detection path. Branch to 74. The condensing lens 76 is branched to the reflected light detection path 74 by the beam splitter 75 to collect the reflected light and guide it to the photo detector 77. The photo detector 77 receives the reflected light guided to the reflected light detection path 74 and outputs a signal (voltage signal) corresponding to the light intensity of the received reflected light to the control means. In this embodiment, the control means uses the control means 8 shown in FIG. 3, and an output signal from the photodetector 77 is input to the input interface 84 as shown in FIG.

The condensing objective lens contamination detection means 7a shown in FIG. 4 is configured as described above, and the procedure for detecting the degree of contamination of the condensing objective lens 532 will be described below.
First, the control unit 8 operates the processing feeding unit 37 and the index feeding unit 38 to position the chuck table 36 constituting the chuck table mechanism 3 immediately below the condenser objective lens 532. Note that it is desirable to place the reflecting mirror M on the suction chuck 361 of the chuck table 36. Next, the control means 8 operates the actuator 732 of the branching means 73 to position the direction changing mirror 731 at the operating position indicated by the two-dot chain line. The control means 8 operates the inspection laser beam oscillator 72 to oscillate the inspection laser beam LB2. The inspection laser beam LB2 oscillated from the inspection laser beam oscillator 72 is held on the chuck table 36 via the beam splitter 75, the direction changing mirror 731 of the direction changing means 73, and the condensing objective lens 532 of the condenser 53. The reflecting mirror M is irradiated. The inspection laser beam LB2 irradiated on the reflecting mirror M is reflected by the reflecting mirror M, and the reflected light is guided to the reflected light detection path 74 via the condenser objective lens 532, the direction changing mirror 731 and the beam splitter 75, and collected. The light is collected by the optical lens 76 and received by the photodetector 77.

  In this way, the photodetector 77 that has received the reflected light of the inspection laser beam LB2 reflected by the reflecting mirror M sends a voltage signal (B) corresponding to the light intensity of the received reflected light to the control means 8. The control means 8 determines whether or not the voltage signal (B) sent from the photodetector 77 exceeds an allowable value of the degree of contamination of the condenser objective lens 532. The allowable value of the degree of contamination of the condensing objective lens 532 is set to 10% of the state where the condensing objective lens 532 is not contaminated. That is, the reflection of the inspection laser beam LB2 oscillated from the inspection laser beam oscillator 72 is held on the chuck table 36 via the beam splitter 75, the direction changing mirror 731 of the branching unit 73, and the uncontaminated condensing objective lens 532. When the voltage signal (B) corresponding to the light intensity when the reflected light when irradiated to the mirror M is received by the photo detector 77 is 1 V, for example, the allowable value of the degree of contamination of the condenser objective lens 532 is 0. Set to 1V. Accordingly, the control means 8 uses a voltage signal (B) corresponding to the intensity of the reflected light of the inspection laser beam LB2 detected by the photodetector 77, corresponding to the light intensity in the state of the condensing objective lens 532 that is not contaminated ( If the value obtained by subtracting the allowable value 0.1V from (1V) (1V−0.1V = 0.9V) or more (B ≧ 0.9V), the allowable value (0 of the degree of contamination of the condenser objective lens 532) .1V) and is determined to be usable. Then, the control unit 8 displays the determination result on the display unit 80 as an alarm unit together with the voltage signal (B) value corresponding to the intensity of the reflected light of the inspection laser beam LB2 detected by the photodetector 77.

  On the other hand, the voltage signal (B) corresponding to the intensity of the reflected light of the inspection laser beam LB2 detected by the photodetector 77 is allowed from the voltage (1V) corresponding to the light intensity in the uncontaminated condensing objective lens 532 state. If the value is less than 0.1V (1V−0.1V = 0.9V) (B <0.9V), the allowable value (0.1V) of the degree of contamination of the condenser objective lens 532 is used. The determination result is displayed, and the determination result is displayed on the display unit 80 as an alarm unit together with the voltage signal (B) value corresponding to the intensity of the reflected light of the inspection laser beam LB2 detected by the photodetector 77. Thus, based on the determination result displayed on the display unit 80 as the alarm unit and the voltage signal (B) value corresponding to the intensity of the reflected light of the inspection laser beam LB2 detected by the photodetector 77, the operator collects the light. Consider cleaning or replacing the objective lens 532. If it is determined that the allowable value of the degree of contamination of the condensing objective lens 532 is exceeded, an alarm buzzer or an alarm lamp may be activated to give an alarm.

2: Stationary base 3: Chuck table mechanism 36: Chuck table 37: Processing feed means 38: Indexing feed means 4: Laser beam irradiation unit 5: Laser beam irradiation means 51: Pulse laser beam oscillation means 52: Output adjustment means 53: Condenser 532: Condensing objective lens 6: Imaging means 7, 7a: Condensing objective lens contamination detection means 71: Output detector 72: Inspection laser beam oscillator 73: Direction changing means 74: Reflected light detection path 75: Beam splitter 76: Collection Optical lens 77: Photodetector 8: Control means W: Workpiece M: Reflector

Claims (3)

Workpiece holding means for holding the workpiece, laser beam irradiation means for laser processing the workpiece held on the workpiece holding means, and the workpiece holding means and the laser beam irradiation means for processing feed direction A laser beam oscillating unit that oscillates the laser beam and condenses the laser beam oscillated from the laser beam oscillating unit to the workpiece holding unit. A laser processing apparatus including a condenser having a condenser objective lens for irradiating a held workpiece,
Condensing objective lens contamination detecting means for detecting the degree of contamination of the condensing objective lens, and an alarm when the degree of contamination of the condensing objective lens detected by the condensing objective lens contamination detecting means exceeds an allowable value Alarm means,
Laser processing equipment characterized by that.   The condensing objective lens contamination detection means includes an output detector that is disposed adjacent to the workpiece holding means and detects an output of a laser beam emitted from the condenser, and an output detected by the output detector. 2. The laser processing according to claim 1, further comprising: a control unit that determines whether or not is less than a predetermined value and outputs an alarm signal to the alarm unit when the output detected by the output detector is less than the predetermined value. apparatus.   The condensing objective lens contamination detection means advances and retreats to and from an operating position and a retracted position along a path connecting the laser beam oscillation means of the workpiece holding means and the laser beam oscillation means of the workpiece holding means and the condenser. Direction changing means for changing the direction of the inspection laser beam oscillated from the inspection laser beam oscillator toward the condenser in a state where the inspection laser beam oscillator is disposed in the operable position, and oscillated from the inspection laser beam oscillator A beam splitter for branching the reflected light of the inspection laser beam irradiated to the workpiece holding means via the direction changing means and the condenser to the reflected light detection path, and to the reflected light detection path by the beam splitter A photodetector that detects the intensity of the reflected light that has been branched, and whether or not the intensity of the reflected light that is detected by the photodetector is less than a predetermined value. Constant and the intensity of the reflected light which the Hotodetekuta is detected and a control means for outputting an alarm signal said alarm means when more than a predetermined value, the laser processing apparatus according to claim 1.