JP2005095936A - Apparatus and method for laser machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for laser machining which can suppress chipping occurring in a cutting point in a groove forming part and reduce an affect on a workpiece caused by spatter (plume) generated during laser beam machining by means of laser irradiation to such a brittle material as a silicon wafer, and also to provide a machining method for suppression of amorphous silicon generation occurring on a cutting section. <P>SOLUTION: The apparatus comprises a laser oscillator 1, an optical means, a beam output control means 4, a beam diameter control means 7 and an output control means 5 which performs irradiation for arbitrary times while changing a beam diameter irradiated to the workpiece by the beam diameter control means. In the case of cutting the workpiece, the cutting is carried out while forming a groove and changing a width of the groove to be cut gradually narrower, so that a path is formed in which the workpiece in a molten state remains without spattering out from the workpiece and moves gradually to the bottom side of the workpiece by a gravitational action. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser processing apparatus and a laser processing method for performing fine processing using laser light.

  In recent years, laser processing apparatuses have been widely used in laser processing applications such as microfabrication and groove formation and cutting of composite materials.

Conventional brittle materials such as silicon wafers are cut by crushing with a mechanical blade or the like. (For example, see Patent Document 1)
FIG. 10 shows the conventional silicon wafer cutting method, in which 64 is a substrate made of a brittle material (silicon wafer or the like), 60 is a laser beam B having an absorption characteristic of the workpiece 64, and 61 is the laser beam. Condensing lenses A and 63 for condensing or projecting the workpiece (brittle material) are circuit layers B and 65 formed on the substrate, and a dicing film for holding the substrate 64 is used.

  The laser processing method configured as described above performs fusing cutting or grooving on the workpiece by condensing the laser beam B60 onto the substrate 64 via the condenser lens A61. At this time, scattered matter from the workpiece generated from the workpiece adheres to the circuit layer B63 of the workpiece again, but it is necessary to remove it by washing or etching in a subsequent process. In addition, in a workpiece processed by the above method (particularly a silicon wafer), a part of the cut cross-section becomes amorphous silicon, so that it remains in a state in which it is easily detached from the divided workpiece. This is a cause of deterioration in product quality and reliability after processing.

In the cutting method using laser light, the workpiece is irradiated with laser light and melted. Alternatively, only the surface of the workpiece is irradiated with laser light to form a stress strain and mechanically cleaved in a subsequent process. Alternatively, a denaturation layer is formed in a part of the workpiece by performing multiphoton absorption by focusing light on a material that normally does not absorb laser light, and mechanically cleaving later. (For example, see Patent Document 2)
FIG. 11 shows the above-described conventional laser processing method, wherein 66 is a laser beam C, and 67 is a condensing lens B for condensing the laser beam C66 on a substrate 64.

The laser processing method configured as described above uses the condensing lens B with the laser beam C66 having a wavelength transmissive to the dicing film B65 and the base material 64, and the condensing point at the center of the base material. The above-mentioned melting is achieved by reducing the mechanical strength by melting only the vicinity of the center of the base material by utilizing the multiphoton absorption generated by increasing the laser light intensity by condensing at a high density to 68. By applying a force to the mechanical strength reduced portion of the denatured region 62, it is mechanically cleaved.
Japanese Patent Laid-Open No. 01-196850 JP 2002-192367 A

  However, conventional groove formation and cutting of brittle materials such as silicon wafers have the problem that the reliability and yield of the wafer are reduced due to chipping (cracks generated at the cut surface) generated during processing or cleaving. In addition, in a workpiece processed by the above-described conventional processing method (particularly a silicon wafer), a part of the cut cross section becomes amorphous silicon, and amorphous silicon particles adhere to the cut cross section and deviate from the divided workpiece. It remains in an easy state and has the problem of reducing the quality and reliability of the product after processing the workpiece.

  In addition, when a groove is formed and cut by irradiating a brittle material such as a silicon wafer with a laser beam using a laser beam, the quality and yield of the workpiece are reduced due to the scattered material generated from the workpiece. It is difficult to easily change the cutting width and the groove width to be formed while maintaining the processing quality.

  An object of the present invention is to provide a laser processing apparatus and a laser processing method for solving the above conventional problems.

  To achieve the above object, the present invention provides a laser oscillator for generating laser light, optical means for guiding the laser light to a workpiece, control means for controlling the output of the laser light, and irradiating the workpiece. A beam diameter control means for changing the beam diameter is provided, and output control means for irradiating an arbitrary number of times while changing the beam diameter irradiated to the workpiece by the beam diameter control means is provided, and is generated from the workpiece. The amount of scattered material and the scattering distance vary depending on the width and depth of the melting region of the workpiece. The wider the width, the larger the amount of scattered material from the workpiece that is generated during laser processing, and the melting region. The deeper the distance, the greater the scattering distance of the scattered object from the workpiece generated during laser processing. However, in the laser processing apparatus of this configuration, the output of the laser beam irradiated to the workpiece, the irradiation beam profile, and the irradiation By varying the chromatography beam diameter, it is possible to realize a processing width and working depth while suppressing the debris generated from the workpiece, the objective.

  Further, the present invention is to irradiate an arbitrary number of times while gradually changing the beam diameter to be irradiated to the workpiece. When cutting the workpiece, the width of the groove to be processed is gradually decreased. While cutting while forming grooves, the molten work piece that remains without splashing from the work piece is gradually formed on the bottom side of the work piece to move by the action of gravity. Realizing high quality and reliable processing by preventing the adhesion of substances in a different state (for example, amorphous crystalline state) from the workpiece attached to the cut cross section of the workpiece by performing the processing Can do.

Further, the present invention provides a laser beam diameter of 50 to 80% of the laser beam diameter of the first irradiation laser beam in a processing method of irradiating the same portion of the workpiece twice or more with the laser. The laser beam is irradiated as the second irradiation laser beam. A groove is formed in the workpiece by the first irradiation laser beam, and processing is performed to a desired depth by the second irradiation laser beam. Damage to the laser beam incident surface of the workpiece due to the weak laser beam component generated on the workpiece surface due to the influence of diffraction or the like of the emitted laser beam component can be prevented, and the first irradiated laser beam can The wall surface of the groove on the formed work piece prevents the scattered material generated from the work piece from being scattered on the work piece when the groove is formed by the second irradiation laser beam, thereby processing the work piece. Quality and confidence It is possible to improve the resistance.

  Further, in the present invention, the workpiece is irradiated with a laser output derived from the following equation for a processing condition in the case of increasing the processing width formed by irradiating the workpiece with laser light. In order to form an arbitrary machining width, when machining with the same machining depth and the only machining width with respect to the rough machining conditions, by using the following formula, It has the effect that the cost can be reduced.

B = A × (r ₂ ² / r ₁ ² ) × 0.8 to 0.9
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Processing point average output after changing In addition, in the present invention, the laser output derived from the following equation for the processing condition in the case of reducing the processing width formed by irradiating the workpiece with laser light is described above. This is a processing method that irradiates an object, and in order to form an arbitrary processing width on the workpiece, the following formula is used when processing with the same processing depth, etc. and only a small processing width, with respect to the approximate processing conditions: By using it, it is possible to reduce the time and cost required for the processing condition setting operation.

B = A × (r ₂ ² / r ₁ ² ) × 1.13 to 1.23
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Processing point average output after changing In addition, the present invention provides a laser oscillator for generating laser light, optical means for guiding the laser light to a workpiece, control means for controlling the output of the laser light, An aperture for removing a part of a laser beam irradiated on a workpiece is provided, and the workpiece is irradiated with laser light using the aperture having an opening of 50% or less of the beam diameter incident on the aperture. By providing an aperture of 50% or less of the incident laser beam diameter in front of the condensing optical system for irradiating the workpiece, only the central portion of the laser beam component incident on the aperture is allowed to pass, so that the workpiece By removing the laser beam component below the processing threshold, the processing cut width can be kept constant in the processing range. In particular, when a workpiece composed of a plurality of layers or a pattern made of a plurality of different materials is formed on the processing surface, the workpiece can be processed with a stable processing width by the above processing method.

  The present invention also provides a laser oscillator for generating laser light, optical means for guiding the laser light to a workpiece, control means for controlling the output of the laser light, and part of a laser beam irradiated to the workpiece. Aperture is removed, and the aperture cuts a laser beam component having an intensity of at least 40% or less of the spatial distribution intensity of the laser beam irradiated to the workpiece. This is a processing method to irradiate, and the workpiece is irradiated with laser light through an aperture for removing a component of 40% or less of the peak intensity of the laser beam incident before the condensing optical system for irradiating the workpiece. As a result, the machining cut width can be kept constant in the machining range, and the machining groove machined by this machining method and the edge of the laser irradiation surface of the cutting part can be machined vertically. It can be.

  Further, the present invention comprises a laser oscillator for generating laser light, a mask for determining a processing width by the laser light, and one or more sheets for changing the beam diameter of the laser light irradiated on the mask. A shaping optical unit; one or more first projection lenses for projecting the beam profile on the mask onto the workpiece; and one or more sheets for projecting onto the sensor for visualizing the beam profile on the mask. A laser processing device that has a second projection lens and a control analysis circuit for processing signals from the sensor. The state of the laser light incident on the mask is constantly monitored by the sensor, and is optimal for the workpiece. By processing the control analysis circuit to determine whether the laser beam is irradiated, it is possible to determine whether the workpiece has been processed normally, and the irradiated laser beam is always applied to the workpiece. Thus, a laser processing apparatus that automatically adjusts the laser oscillator, the shaping optical system, and the mask position so as to be optimal for processing the workpiece can be provided by feeding back a signal from the control analysis circuit so as to be optimal. .

  As described above, the present invention suppresses the scattering from the workpiece due to laser beam processing, suppresses the generation of molten residue adhering to the workpiece cross section, and easily processes while maintaining the processing quality. In addition to providing a laser processing apparatus that changes the processing width of an object, and also providing a processing method that solves the above problems by a processing method that suppresses scattered matter from a workpiece and molten residue adhering to a cut section, By producing using the above laser processing apparatus and processing method, a highly reliable silicon wafer can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
1 and 2, reference numeral 1 denotes a laser oscillator that oscillates polarized laser light. Reference numeral 2 denotes an output control component which is an output control means for controlling the output of the laser beam irradiated to the workpiece 19. The 1 / 2λ plate 11, the rotary stage 12 for rotating the 1 / 2λ plate 11, and the laser beam The optical polarization element 13 is reflected or transmitted according to the polarization direction, and the damper 14 is for dumping the laser light reflected by the optical polarization element 13. Reference numeral 3 denotes a beam diameter control unit which is a beam diameter control means, and includes a first shaping lens 15 that changes the beam diameter of the laser light irradiated on the mask 18, a second shaping lens 16, and a movable stage 17. Yes. A laser control power source 4 drives the laser oscillator 1 and controls the oscillation conditions. Reference numeral 7 denotes an optical control circuit for controlling the movable stage 17 for changing the position of the second shaping lens 16 constituting the beam diameter control configuration unit 3. Reference numeral 6 denotes a mask switching control circuit for rotating the mask 18. A main control circuit 5 controls the entire apparatus. A bend mirror 10 guides the laser beam to the workpiece 19. Reference numeral 8 denotes a laser beam A that is shaped and controlled by the output control configuration unit 2 and the beam diameter control configuration unit 3. Reference numeral 9 denotes a processing projection lens for reducing and projecting (condensing) the beam profile on the mask 18 onto the workpiece 19. Reference numeral 19 denotes a workpiece. Reference numeral 20 denotes a movable table for controlling the laser beam irradiation position on the workpiece 19. Reference numeral 21 denotes a mask rotation axis for rotating the mask 18. Reference numeral 22 denotes a mask upper hole having a plurality of different hole diameters provided on the mask 18 for controlling the laser beam passing rate (or the shaping state).

  The operation of the laser processing apparatus configured as described above will be described.

  According to the present embodiment, the amount of scattered matter generated from the workpiece 19 and the scattering distance vary depending on the width and depth of the melting region of the workpiece, and the workpiece that is generated during laser processing as the width is wider. The amount of scattered matter from the object 19 increases, and the scattered distance of the scattered object from the workpiece 19 generated during laser processing increases as the melting region increases. In this configuration, when the output of the laser beam 8 irradiated to the workpiece 19 and the irradiation beam diameter are processed to a desired processing width and depth, the scattering distance from the workpiece 19 is less than the allowable value. The main control circuit 5 controls the output control component 2, the beam diameter control component 3, and the laser control power supply 4 to optimize the laser output, the beam profile of the irradiation beam diameter, and the irradiation beam diameter. It is possible to provide a laser processing apparatus that realizes a target processing width and processing depth while suppressing scattered matter generated from the processed material.

  In the first embodiment, the 1 / 2λ plate and the optical polarizing element are used for controlling the laser output, but an electro-optical element (EOM) or the like may be used.

(Embodiment 2)
In the present embodiment, the same portions as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 1, reference numeral 5 denotes a main control circuit, which issues a command to the mask switching control circuit 6 on the laser irradiation sheet when processing the workpiece 19. The difference from the first embodiment is that in the laser processing apparatus that performs processing by irradiating the workpiece 19 with the laser beam a plurality of times at the same location, each time the workpiece 19 is irradiated with laser light by the main control circuit 5. This is that a function of automatically switching the mask upper hole 22 to be used is added.

  As described above, according to the present embodiment, when the workpiece 19 is cut, the workpiece is gradually cut by forming the groove while gradually changing the width of the groove to be processed. The cross section of the work piece 19 is cut by forming a path for the molten work piece 19 remaining without being scattered from the work piece 19 to move to the bottom side of the work piece 19 due to the action of gravity. By preventing adhesion of a substance in a state (for example, an amorphous crystal state) different from the workpiece 19 attached to the surface, a laser processing apparatus that realizes processing with high quality and reliability can be provided.

(Embodiment 3)
The present embodiment is a processing method using the laser processing apparatus of the above-described embodiment, and when the workpiece 19 is cut, the beam diameter of the first laser light applied to the workpiece 19 is desired. After grooving or cutting with a beam diameter for realizing a machining width of, a second laser beam having a beam diameter smaller than the beam diameter is irradiated to the same portion of the workpiece irradiated with the first laser beam. Thus, by removing the melt remaining on the wall surface of the groove formed by the first laser beam, a state different from the workpiece adhered to the processing groove and the cut wall surface of the workpiece (for example, an amorphous crystal) By removing the material in the state) by ablation, processing with high quality and reliability of the workpiece can be realized.

(Embodiment 4)
This embodiment relates to a processing method using the laser processing apparatus shown in the above-described embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted. In FIG. 3, 23 is a circuit layer A formed on the surface of the workpiece 19, 24 is a dicing film A for holding the workpiece 19, 25 is a first laser beam for irradiating the workpiece, 26 Is the second laser beam, 27 is the third laser beam, 28 is the fourth laser beam, 29 is the first processed groove processed by the first laser beam, and 30 is processed by the second laser beam. The second processed groove 31 is a third processed groove processed by the third laser beam, and 32 is a fourth processed groove processed by the fourth laser beam.

  A first processed groove is formed by irradiating the workpiece 19 with a first laser beam 25. Next, a second laser beam 26 having a smaller beam diameter than the first laser beam 25 is processed. The second processed groove 30 is formed by irradiating the same portion where the first processed groove 29 of the object 19 is formed. Similarly, the third laser light 27 having a smaller beam diameter than the second laser light 26. Is applied to the same portion of the workpiece 19 where the second processed groove 30 is formed, thereby forming a third processed groove 31. Further, a fourth beam diameter smaller than that of the third laser beam 27 is formed. The workpiece is cut by forming the fourth machining groove 31 by irradiating the laser beam 28 to the same portion of the workpiece 19 where the third machining groove 31 is formed.

  As described above, according to the present embodiment, by cutting while forming the groove while gradually changing the width of the groove to be processed, the workpiece in a molten state that remains without being scattered from the workpiece 19 The workpiece 19 is different from the workpiece 19 that adheres to the cut cross section of the workpiece 19 by performing a machining while forming a path for moving by the action of gravity on the bottom surface side of the workpiece 19. Attachment of a substance in a state (for example, an amorphous crystal state) can be prevented.

(Embodiment 5)
This embodiment relates to a processing method using the laser processing apparatus shown in the above-described embodiment, and the same parts are denoted by the same reference numerals and detailed description thereof is omitted. In FIG. 4, 33 is a laser beam A irradiated to the workpiece 19, and 34 is a laser beam B having a beam diameter of 50 to 80% of the first laser beam A irradiated to the workpiece 19. , 35 is a processing width A formed on the workpiece 19 by the laser beam A, and 36 is a processing formed by the laser beam B irradiated to the same position as the processing width A formed on the workpiece 19. Width B.

  A groove is formed in the workpiece 19 by the laser beam A33, a processing width B36 smaller than the processing width A35 formed by the laser beam 34 is formed, and the non-remaining non-remaining portions on both sides of the processing width B36 by the laser beam A33. By removing the processed portion and irradiating the processed width A35 portion again with the laser beam B34 to perform processing to a desired depth, due to the influence of diffraction of the laser beam component emitted from the laser processing apparatus. Damage to the laser light incident surface of the workpiece 19 due to the weak laser beam component generated on the surface of the workpiece 19 can be prevented, and a groove on the workpiece 19 formed by the first irradiation laser beam. The wall surface acts as a wall that prevents scattering of the scattered matter generated from the work piece 19 when the groove is formed by the second irradiation laser light onto the work piece 19, thereby By scattered material from the workpiece 19 generated with the The processing is prevented from adhering to the workpiece 19 surface, thereby improving the machining quality and reliability of the workpiece 19.

(Embodiment 6)
In the present embodiment, since an arbitrary processing width is formed on the workpiece using the laser processing apparatus described above, processing with the same processing depth and the like but with a large processing width is performed with respect to the approximate processing conditions. In this case, it is possible to reduce the time and cost required for work such as processing condition determination by using the following equation.

B = A × (r ₂ ² / r ₁ ² ) × 0.8 to 0.9
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Machining point average output after changing

For example, approximate machining point average output A = 2W
Approximate machining width r ₁ = 70 μm Set machining width r ₂ = 100 μm
In this case, the optimum machining point output B is
^{B = 2 × (100 2/} 70 2) × 0.85
= 3.47W
It becomes.

(Embodiment 7)
In this embodiment, since an arbitrary processing width is formed on the workpiece using the laser processing apparatus described above, processing is performed with the processing depth being the same and the processing width only being small with respect to the approximate processing conditions. In this case, it is possible to reduce the time and cost required for work such as processing condition determination by using the following equation.

B = A × (r ₂ ² / r ₁ ² ) × 1.13 to 1.23
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Processing point average output after changing, for example
Approximate machining point average output A = 2W
Approximate machining width r ₁ = 70 μm
In case of set processing width r ₂ = 50μm
In this case, the optimum machining point output B is
^{B = 2 × (50 2/} 70 2) × 1.18
= 1.20W
It becomes.

(Embodiment 8)
In the present embodiment, the same portions as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. 5 to 7, reference numeral 39 denotes a mask incident laser beam representing the intensity distribution of the laser beam incident on the aperture (mask), 40 denotes a first mask having an aperture that is half the beam diameter of the mask incident laser beam, and 41 denotes A second mask having an aperture equivalent to the beam diameter of the mask incident laser light, 42 is a mask passing laser light A representing the intensity distribution of the laser light that has passed through the first mask 40, and 43 is the second mask 41. The mask passing laser beams B and 53 representing the intensity distribution of the laser beam passing through are melted regions processed by the laser beam.

  The laser beam B passing through the mask whose intensity distribution of the laser beam incident before the condensing optical system for irradiating the workpiece 19 is shaped using an aperture having the same size as the mask incident laser beam 39 is processed. When the processing groove or cutting is performed by irradiating 19, the first mask having an opening diameter of 50% of the beam diameter 44 of the mask incident laser beam 39 is formed in a tapered shape near the surface of the workpiece 19. By passing through 40, the processed mask 19 is irradiated with the shaped mask passing laser beam A to perform processing grooves or cutting, thereby realizing non-tapered processing in the vicinity of the surface of the processing object 19.

  As described above, according to the present embodiment, the laser beam passing through the mask is 50% of the laser beam diameter of the mask incident laser beam 39 before reaching the optical system that focuses and irradiates the workpiece 19 with the laser beam. By irradiating the workpiece 19 with A42, the processing cut width can be kept constant in the processing range. In particular, the workpiece 19 formed of a plurality of different materials, or a groove caused by a difference in the processing threshold of the workpiece 19 by the above-described processing method when a pattern of a plurality of different materials is formed on the processing surface. It is possible to prevent the instability of the groove width and the cutting width that occur during processing and cutting, and it is possible to perform processing with a stable processing width.

(Embodiment 9)
In the present embodiment, the same portions as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 8, 37 is a Gaussian distribution intensity waveform (intensity change waveform from the beam center) indicating the intensity in the radial direction from the beam center of the laser light waveform having a Gaussian distribution, and 38 is the beam center of the laser light waveform having a Gaussian distribution. 5 shows a Gaussian volume waveform (laser volume change waveform from the center of the beam) indicating the output level in the radial direction.

  The workpiece 19 is irradiated after the laser beam is shaped by the beam diameter control component 3 using an aperture (mask) that deletes 40% or less of the laser beam intensity on the spatial distribution of the laser beam.

  As described above, according to the present embodiment, the intensity distribution of the laser beam applied to the workpiece 19 is changed to the laser beam intensity on the spatial distribution by the second shaping lens of the beam diameter control component 3 and the mask 18. By the processing method of irradiating the workpiece 19 with the laser beam from which the component having the intensity of 40% or less is deleted, the processing cut width can be kept constant in the processing range, and the processing groove processed by this processing method Further, by realizing a process in which the edge of the laser irradiation surface of the cutting part is vertical, a process produced from the work piece 19 by machining the work piece without leaving a margin for machining the work piece 19 By increasing the density of the product, it is possible to realize processing with high reliability and yield and improve production efficiency.

(Embodiment 10)
In the present embodiment, the same portions as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. 9, 46 is a pulse laser oscillator, 47 is an acoustooptic device for controlling the laser output and oscillation frequency incorporated in the laser resonator 46, 48 is a laser drive power source for operating the laser oscillator 46, 49 Is a main control unit for controlling the image analysis unit 52 for image analysis of the signals from the acousto-optic element 47, the laser driving power supply 48, the movable stage 17, the mask 18 and the CCD sensor 51, and 50 is a CCD for the beam profile at the mask position. The profile projection lens for projecting on the sensor 51 is shown.

  The operation of the laser processing apparatus configured as described above will be described.

  The laser beam incident on the mask 18 is always monitored by the CCD sensor 51 and the image analysis unit 52 for the irradiation position, intensity distribution, and passage output of the laser beam on the mask 18, and the optimum laser for the workpiece 19. The main controller 49 controls the operation of the acoustooptic device 47 to optimize the output of the pulse laser oscillator 46 and changes the position of the second shaping lens 16 so that the light is irradiated. By optimizing the beam diameter of the laser beam irradiated on the substrate and changing the moving speed of the movable table 20, the automatically irradiated laser beam and the processing speed are always optimized for the workpiece 19. To.

  As described above, according to the present embodiment, the acoustooptic device 47, the laser drive power supply 48, the movable stage 17, the mask so that the main control unit 49 can always perform stable processing by the signal from the image analysis unit 51. 18. By optimizing the movable table 20, it is possible to provide a laser processing apparatus that automatically adjusts the laser oscillator, the shaping optical system, and the mask position so as to be optimal for processing the workpiece.

  The laser processing apparatus and the laser processing method of the present invention suppress the scattered matter from the workpiece accompanying laser beam processing, suppress the generation of molten residue adhering to the workpiece cross section, and maintain the processing quality. It easily changes the processing width of the workpiece, and is useful for workpieces that require fine processing such as silicon wafers.

The apparatus block diagram in Embodiment 1 and 2 of the laser processing apparatus of this invention Front view of mask in first and second embodiments of laser processing apparatus of the present invention Processing method diagram in Embodiment 4 of the laser processing method of the present invention Processing method diagram in Embodiment 5 of the laser processing method of the present invention Processing method diagram in embodiment 8 of laser processing method of the present invention Processing method diagram in embodiment 8 of laser processing method of the present invention Processing method diagram in embodiment 8 of laser processing method of the present invention Method explanatory drawing in Embodiment 9 of the laser processing method of the present invention The apparatus block diagram in Embodiment 10 of the laser processing method of this invention Processing method diagram of conventional laser processing method Processing method diagram of conventional laser processing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Output control structure part 3 Beam diameter control structure part 4 Laser control power supply 5 Main control circuit 6 Mask switching control circuit 7 Optical control circuit 8 Laser beam A
9 Processing Projection Lens 10 Bend Mirror 11 1 / 2λ Plate 12 Rotating Stage 13 Optical Polarizing Element 14 Damper 15 First Shaping Lens 16 Second Shaping Lens 17 Movable Stage 18 Mask 19 Workpiece 20 Movable Table 21 Mask Rotating Shaft 22 On Mask Hole 23 Circuit layer A
24 Dicing Film A
25 First laser light 26 Second laser light 27 Third laser light 28 Fourth laser light 29 First processed groove 30 Second processed groove 31 Third processed groove 32 Fourth processed groove 33 Laser light A
34 Laser light B
35 Processing width A
36 Processing width B
37 Intensity waveform of Gaussian distribution 38 Volume waveform of Gaussian distribution 39 Mask incident laser light 40 First mask 41 Second mask 42 Mask passing laser light A
43 Masked laser beam B
44 Mask Incident Beam Diameter 45 Mask Passing Beam Diameter 46 Pulse Laser Oscillator 47 Acoustooptic Element 48 Laser Drive Power Supply 49 Main Control Unit 50 Profile Projection Lens 51 CCD Sensor 52 Image Analysis Unit 53 Melting Area 60 Laser Light B
61 Condensing lens A
62 Melting denaturation region 63 Circuit layer B
64 Substrate 65 Dicing film B
66 Laser light C
67 Condensing lens B
68 Focusing point

Claims (16)

A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing apparatus provided with output control means for irradiating an arbitrary number of times while changing the beam diameter irradiated to the workpiece by the beam diameter control means. A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing apparatus provided with output control means for irradiating an arbitrary number of times while gradually changing the beam diameter irradiated to the workpiece by the beam diameter control means. The laser processing apparatus according to claim 1, wherein the workpiece is irradiated with laser light having a wavelength of 200 nm to 1200 nm. A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing method that uses a laser processing device to irradiate a workpiece multiple times while changing the diameter of the laser beam irradiated to the workpiece. A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing method that uses a laser processing apparatus to irradiate a workpiece multiple times by gradually changing the laser beam diameter to be irradiated. When the laser beam is irradiated twice or more to the same position of the workpiece, a laser beam diameter of 50 to 80% of the laser beam diameter of the first irradiation laser light is irradiated as the second irradiation laser light. Laser processing method. A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing method for irradiating the workpiece with a laser output derived from the following equation for a processing condition in the case of increasing the processing width formed by irradiating the workpiece with laser light using the laser processing apparatus.
B = A × (r ₂ ² / r ₁ ² ) × 0.8 to 0.9
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Machining point average output after changing A laser oscillator for generating laser light; optical means for guiding the laser light to the workpiece; control means for controlling the output of the laser light; and beam diameter control means for changing the beam diameter irradiated to the workpiece. A laser processing method for irradiating the workpiece with a laser output derived from the following equation for processing conditions when the processing width formed by irradiating the workpiece with laser light is reduced.
B = A × (r ₂ ² / r ₁ ² ) × 1.13 to 1.23
r ₁ : Machining width before changing the machining width
r ₂ : Desired machining width to be changed
A: Machining point average output before changing the machining width
B: Machining point average output after changing A laser oscillator for generating laser light, optical means for guiding the laser light to the workpiece, control means for controlling the output of the laser light, and an aperture for removing a part of the laser beam irradiated to the workpiece A laser processing method for irradiating a workpiece with a laser beam using the aperture having an aperture of 50% or less of the beam diameter incident on the aperture using the laser processing apparatus. A laser oscillator for generating laser light, optical means for guiding the laser light to the workpiece, control means for controlling the output of the laser light, and an aperture for removing a part of the laser beam irradiated to the workpiece The laser beam that has passed through the aperture that cuts a laser beam component having an intensity of at least 40% or less of the spatial distribution intensity of the laser beam irradiated to the workpiece is applied to the workpiece. Laser processing method to irradiate. The laser processing method according to any one of claims 4 to 10, wherein a laser beam having a wavelength of 200 nm to 1200 nm is used. The laser processing method according to claim 4, wherein a silicon wafer is used as the workpiece. A laser oscillator for generating laser light, a mask for determining a processing width by the laser light, a shaping optical unit composed of one or more pieces for changing the beam diameter of the laser light irradiated on the mask, and a mask One or more first projection lenses for projecting the upper beam profile onto the workpiece, and one or more second projection lenses for projecting the beam profile on the mask onto a sensor for viewing. A laser processing apparatus having a control analysis circuit for processing a signal from a sensor. The laser processing apparatus according to claim 13, wherein the mounted laser oscillator can oscillate pulsed light. The laser processing apparatus according to claim 14, wherein the mounted laser oscillator is a laser oscillator capable of varying a repetition frequency and a pulse peak output. 16. The laser processing apparatus according to claim 15, wherein an AOM or an EOM is mounted in the optical resonator as means for varying the pulse peak output.

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