KR20120100771A - Laser machining apparatus - Google Patents

Abstract

PURPOSE: A laser processing apparatus is provided to check the contamination of a lens protection cover without removing the lens protection cover from a condenser using a camera unit arranged opposite to the condenser. CONSTITUTION: A laser processing apparatus comprises a chuck table, a laser irradiator, and a processing transfer unit. The laser irradiator includes a generator generating a laser beam and a condenser(31) condensing the laser beam from the generator. The condenser comprises an objective lens(320) concentrating the laser beam on a work piece and a lens protection cover(342) arranged between the objective lens and the work piece to block scrap scattering from the work piece toward the objective lens. A camera unit is arranged opposite to the condenser to detect the contamination of the lens protection cover. [Reference numerals] (71) First memory unit; (72) Second memory unit; (73) Determination unit; (AA) Air

Description

Laser processing device {LASER MACHINING APPARATUS}

The present invention relates to a laser processing apparatus for processing a workpiece by laser irradiation.

A plurality of devices, such as IC and LSI, are partitioned by a division scheduled line, and the wafer formed on the surface is formed into individual devices by cutting along a division scheduled line and used for various electronic devices. For example, a laser processing apparatus can be used for cutting the division scheduled line.

As a laser processing apparatus, the chuck table which hold | maintains a to-be-processed object, the laser irradiation means which irradiates a laser beam with respect to the to-be-processed object hold | maintained on a workpiece, and the process which processes and conveys a chuck table and a laser irradiation means relatively, The thing of the structure provided with a conveying means is known (for example, refer patent document 1).

In addition, when the droplets scattered by processing adhere to the objective lens constituting the imaging means, the expensive objective lens must be replaced and the running cost becomes expensive, so that the lens protective cover between the workpiece and the objective lens The device which arrange | positioned and arrange | positioned so that a droplet does not adhere to an objective lens was also developed, and it has been patented by this applicant (for example, refer patent document 2).

Japanese Patent Laid-Open No. 2007-69249 Japanese Patent Publication No. 2009-38181

In the laser processing apparatus, since fragments scatter from the workpiece by processing, the fragments can be attached to a lens protective cover that protects the objective lens in the laser irradiation means. However, in order to confirm whether or not debris adheres to the lens protective cover, the lens protective cover must be periodically removed from the condenser, which causes troublesome management of the lens protective cover.

In addition, even if the debris is attached to the lens protective cover, if the debris is not attached to the condensing path of the laser beam, the operator should properly determine whether the lens protective cover needs to be replaced even though the lens protective cover is not necessary to be replaced. Since this cannot be done, there is a problem that the lens protective cover is unnecessarily replaced.

This invention is made | formed in view of such a problem, and makes it a subject to make it possible to detect the contamination of the lens protective cover of a laser irradiation means suitably in a laser processing apparatus.

The present invention relates to a chuck table for holding a work piece, laser irradiation means for irradiating a work piece held on the chuck table to perform processing, and a processing transport means for relatively processing and conveying the chuck table and the laser irradiation means. A laser processing apparatus comprising at least a laser processing apparatus comprising: an oscillator for oscillating a laser beam, and a condenser for condensing a laser beam oscillated by the oscillator, and the condenser is an objective lens for condensing a laser beam on a workpiece. And a lens protective cover disposed between the objective lens and the workpiece and preventing debris from scattering from the workpiece to prevent contamination of the objective lens, and the imaging means is disposed opposite the condenser, and the lens protective cover is contaminated. Is detected.

In the above laser processing apparatus, the imaging means includes: first storage means for photographing an unprotected lens protective cover and storing an image, second storage means for periodically photographing a lens protective cover and storing an image, and a first It is preferable that it is comprised by the judgment part which compares the image memorize | stored in the memory | storage means and a 2nd memory means, and informs replacement | exchange of a lens protective cover, when a different part exceeds the allowable value.

In the present invention, since the image pickup means is disposed at a position facing the collector, the contamination of the lens protective cover can be detected, so that the contamination of the lens protective cover can be confirmed without removing the lens protective cover from the collector.

In addition, the imaging means includes: first storage means for photographing an unprotected lens protective cover and storing an image, second storage means for periodically photographing a lens protective cover and storing an image, first storage means, and second Since the judgment part which compares the image memorize | stored in the memory means and replaces a lens protective cover when a difference part exceeds the allowable value is provided, the problem that a lens protective cover is replaced unnecessarily is eliminated.

1 is a perspective view illustrating an example of a laser processing apparatus.
2 is a sectional view schematically showing a light collector.
3 is a sectional view schematically showing the lens protective cover and its supporting mechanism.
It is explanatory drawing which shows the imaging means arrange | positioned in the position which opposes a light collector.
It is a perspective view which shows the state which laser-processes a to-be-processed object.

The laser processing apparatus 1 shown in FIG. 1 is an apparatus which performs laser processing by the laser irradiation means 3 with respect to the workpiece hold | maintained by the chuck table 2, The chuck table 2 is a process feed means. (4) is supported in the processing feed direction (X-axis direction) so as to enable processing feed, and is moved by the indexing feed means 5 in the indexing feed direction (Y-axis direction) orthogonal to the X-axis direction in the horizontal direction. Possibly supported.

The processing feed means 4 is connected to a ball screw 40 having an axial center in the X-axis direction, a pair of guide rails 41 disposed in parallel with the ball screw 40, and one end of the ball screw 40. The motor 42 and the internal nut which are not shown in figure are screwed to the ball screw 40, and the lower part is comprised by the slide part 43 which slide-contacts the guide rail 41. As shown in FIG. The work conveying means 4 is driven by the motor 42 and the ball screw 40 is rotated, so that the slide portion 43 slides on the guide rail 41 in the X-axis direction so that the chuck table 2 And the indexing conveying means 5 are moved in the X-axis direction.

The indexing conveying means 5 is connected to the ball screw 50 which has an axial center of a Y-axis direction, a pair of guide rails 51 arrange | positioned in parallel with the ball screw 50, and one end of the ball screw 50. The motor 52 and the internal nut which are not shown in figure are screwed to the ball screw 50, and the lower part is comprised by the base 53 which slides in contact with the guide rail 51. As shown in FIG. The indexing conveying means 5 is driven by the motor 52 and the ball screw 50 is rotated, so that the base 53 slides on the guide rail 51 in the Y-axis direction to move the chuck table 2. It is a structure which moves to a Y-axis direction.

The laser irradiation means 3 which irradiates a laser beam with respect to the workpiece hold | maintained by the chuck table 2, and the position which should be processed are detected above the movement path of the chuck table 2 in the process feed direction. Alignment means 6 to be arrange | positioned is arrange | positioned. The alignment means 6 is equipped with the camera 60 which picks up a to-be-processed object.

The laser irradiation means 3 is provided with the oscillator 30 which oscillates a laser beam, and the condenser 31 which condenses the laser beam which oscillator 30 oscillated.

As shown in FIG. 2, the objective lens case 32 is provided in the lower end of the condenser 31. As shown in FIG. The objective lens case 32 is disposed on the optical path of the laser beam, and holds the objective lens 320 that focuses the laser beam on the workpiece.

The objective lens case 32 is covered by the cover member 33. Under the cover member 33, a shielding portion 34 for preventing adhesion of debris generated by laser processing to the objective lens 320 is disposed.

On the side of the cover member 33, an air introduction portion 330 for introducing air is formed. The air introduction part 330 communicates with the air chamber 331 which is a space formed between the objective lens case 32 and the inner periphery of the cover member 33.

As shown in FIG. 3, the shield part 34 is equipped with the annular frame 340 and the lens protective cover 342 hold | maintained by the holding part 341 of which the outer peripheral part was annular. The lens protective cover 342 is formed of, for example, a glass plate, and is disposed to be positioned between the objective lens 320 and the workpiece during laser processing, and blocks the fragments scattered from the workpiece to prevent the objective lens 320. To achieve the role of preventing contamination.

The annular frame 340 is provided with a plurality of pores 340a for blowing air along the lower surface of the lens protective cover 342 at predetermined intervals in the circumferential direction. The pore 340a communicates with the air flow path 340b formed on the outer circumferential side of the lens protective cover 342. The air flow path 340b communicates with the air chamber 331 shown in FIG. 2. The air curtain can be formed by blowing air from the pores 340a.

As shown in FIG. 1, the imaging means 7 is arrange | positioned at the slide part 43 which comprises the process feed means 4. As shown in FIG. As shown in FIG. 4, the imaging means 7 is arrange | positioned in the position which can image the lens protection cover 342 facing the condenser 31. As shown in FIG.

The imaging means 7 is provided with the camera part 70 and the 1st memory means 71 and the 2nd memory means 72 which consist of memory elements, such as a memory. The first storage unit 71 and the second storage unit 72 have a function of storing image information acquired by the camera unit 70. The first storage unit 71 and the second storage unit 72 are connected to a determination unit 73 that is constituted by a CPU or the like and has a determination function, and the determination unit 73 is the first storage unit 71. The contamination of the lens protective cover 342 can be detected by comparing the image information stored in the image information and the image information stored in the second storage means 72 and extracting the different portions. In addition, the image acquired by the camera unit 70 can be displayed on the monitor 8.

In the case where the workpiece W is laser processed using the laser processing apparatus 1 shown in FIG. 1, the workpiece W is adhered to the tape T to be supported by the ring-shaped frame F and the chuck It is held in the table 2. Then, it is driven by the indexing conveying means 5 and moved in the Y-axis direction, after adjusting the position in the Y-axis direction between the division scheduled line to be processed and the condenser 31, and then driven by the processing conveying means 4 The chuck table 2 moves in the X-axis direction, and as shown in FIG. 5, the laser beam 35 is irradiated to the workpiece W from the condenser 31, and the division scheduled line L is ablation processed. Thus, the groove G is formed. For example, processing is performed under the following conditions.

(A) Type of laser: YVO4, YAG laser,

(B) Wavelength: 355 [nm] (ultraviolet light)

(C) output: 4 [W]

(D) Condensing spot diameter: Φ10 [㎛]

(E) Repeat frequency: 50 [Hz]

(F) Cutting feed speed: 100 [㎜ / s]

When ablation processing is performed, processing debris called debris is ejected from the workpiece. Although these fragments scatter, as shown in FIGS. 2 and 3, since the condenser 31 includes the lens protective cover 342, the fragments can be prevented from adhering to the objective lens 320.

On the other hand, during processing, even if air is ejected from the pores 340a shown in FIG. 3 to form an air curtain, as shown in the monitor 8 in FIG. 4, the lens protection cover 342 has debris 90. 91 may be attached.

These fragments 90 and 91 can be detected by imaging the lens protective cover 342 by the imaging means 7. Since the operator can check the fragments 90 and 91 displayed on the monitor 8, the operator can confirm the contamination of the lens protective cover 342 without removing the lens protective cover 342 from the condenser 31, The lens protective cover 342 can be replaced at an appropriate timing.

In addition, before the start of the laser processing, that is, the lens protective cover 342 in which the debris does not scatter and is free of contamination is imaged in advance, and the image information is stored in the first storage means 71. During the laser processing, The image information acquired by periodically capturing the lens protective cover 342 is stored in the second storage means 72, and stored in the first storage means 71 and the second storage means 72 in the determination unit 73. The compared images are compared one after another. The operator can be notified of the timing at which the lens protective cover 342 needs to be replaced by emitting an alarm sound or displaying a warning screen on the monitor 8 when the difference portion exceeds the allowable value. In this way, it is possible to prevent the lens protective cover 342 from being unnecessarily replaced.

As shown in the monitor 8 in FIG. 4, since the central portion of the lens protective cover 342 is the light condensing path 342a of the laser beam, the debris 91 is attached to the light condensing path 342a. If there is, it becomes an obstacle to a laser beam, and cannot evenly irradiate a division plan line. That is, even if the debris 90 is attached to an area other than the condensing path 342a, the replacement of the lens protective cover 342 is unnecessary unless the debris is attached to the condensing path 342a.

Therefore, the determination unit 73 sequentially acquires the image information of the lens protective cover 342 in the absence of contamination stored in the first storage unit 71 and the image information stored in the second storage unit 72. In comparison, when the debris attached to the condensing path 342a is detected by image processing, it is necessary to emit an alarm sound or display a warning screen on the monitor 8 to replace the lens protective cover 342. Notify the operator. And the operator can perform laser irradiation suitably by replacing the lens protective cover 342. As shown in FIG.

In addition, in the example shown in FIG. 1, although the imaging means 7 is being fixed to the slide part 43, if the imaging means 7 is a position which can detect the contamination of the lens protective cover 342, It can arrange | position besides the position shown.

1: laser processing device 2: chuck table
3: laser irradiation means 30: oscillator
31: condenser 32: objective lens case
320: objective lens 33: cover member
330: air inlet 331: air chamber
34: shield 340: annular frame
340a: pore 340b: air flow path
341: holder 342: lens protective cover
342a: condensing path 4: processing feed means
40: ball screw 41: guide rail
42: motor 43: slide portion
5: indexing conveying means 50: ball screw
51: guide rail 52: motor
53: base 6: alignment means
60 camera 7 imaging means
70 camera portion 71 first storage means
72: second storage means 73: judgment unit
8: monitor

Claims (2)

A chuck table for holding the workpiece, laser irradiation means for irradiating the workpiece held by the chuck table with a laser beam, and a machining feed means for relatively processing and conveying the chuck table and the laser irradiation means. As a laser processing apparatus provided at least,
The laser irradiation means includes an oscillator for oscillating a laser beam and a condenser for condensing the laser beam oscillated by the oscillator,
The condenser includes an objective lens for focusing a laser beam on the workpiece, and a lens protective cover arranged between the objective lens and the workpiece to block debris from the workpiece to prevent contamination of the objective lens. and,
An imaging device is disposed opposite the light collector, and detects contamination of the lens protective cover. The image pickup apparatus according to claim 1, wherein the imaging means comprises: first storage means for photographing the lens protective cover free of contamination and storing an image, second storage means for periodically photographing the lens protective cover and storing an image; And a judging section for comparing the images stored in the first storage means and the second storage means and informing replacement of the lens protective cover when the difference portion exceeds the allowable value.

Images