JP5096040B2 - Laser processing method and laser processed product - Google Patents

Description

  The present invention includes various sheet materials, circuit substrates, semiconductor wafers, glass substrates, ceramic substrates, metal substrates, light emitting or receiving element substrates such as semiconductor lasers, MEMS substrates, semiconductor packages, cloth, leather, paper, film materials, etc. The present invention relates to a laser processing method and a laser processed product that perform processing such as cutting and drilling on a workpiece using a laser.

  With the recent miniaturization of electrical and electronic equipment, the miniaturization of parts and high definition have progressed, and the outline processing of various materials has been required to have high precision and high accuracy with processing accuracy of ± 50 μm or less. ing. Processing such as cutting and drilling of workpieces using laser light has advantages such as high speed, fineness, cut surface quality, and freedom of processing shape. From this point of view, metal, glass, resin Widely used regardless of materials such as semiconductors and ceramics.

  However, since material processing using laser is performed by melting or decomposition reaction due to light absorption of the workpiece, it is around the laser processing portion on the processing surface side (laser light irradiation surface side) of the workpiece. There exists a problem that decomposition products, such as carbon, adhere. Therefore, in order to remove this decomposition product, a post-process called alcohol wiping, washing or desmear is essential.

  In particular, in the periphery of the cut end surface on the processed surface side of the workpiece, the decomposed material scatters upward, so that the amount of deposition is large. The amount of deposited residue on the irradiation side increases in proportion to the power of the laser beam. Therefore, when the workpiece is irradiated with laser light with high power in order to cut at high speed, the deposition of decomposed residue increases, and it becomes difficult to remove the decomposed residue in a subsequent process. In the case of a residue of decomposition product that adheres strongly, wet desmearing with an aqueous potassium permanganate solution or the like is generally performed, but in this case, there is also a problem of an increase in environmental load due to waste liquid treatment. As a method for avoiding such a problem, a method using both a YAG fundamental wave and a water jet has also been proposed. According to this method, although deposition of decomposition products at the edge portion is reduced by the cooling effect of the water jet, There is a problem in material selectivity, such as being incompatible with hygroscopic materials.

JP 2002-343747 A

  The present invention has been made in view of the above-described conventional problems, and its purpose is to effectively reduce contamination of the surface of a workpiece by a decomposition product when processing the workpiece by laser light, It is an object of the present invention to provide a laser processing method capable of performing laser processing efficiently and easily. Another object of the present invention is to provide a laser processed product obtained by the laser processing method.

  The inventors of the present application have studied a laser processing method and a laser processed product in order to solve the conventional problems. As a result, it has been found that the above object can be achieved by adopting the following configuration, and the present invention has been completed.

  That is, the method of manufacturing a laser processed product according to the present invention is a laser processing method for processing a workpiece by irradiating the workpiece with a laser beam in order to solve the above-described problem. The laser processing is performed while the decomposition product generated in the step is sucked and removed in the vicinity of the irradiated portion.

  When the workpiece is irradiated with laser light, a decomposition product is generated by the melting or decomposition reaction of the workpiece at the irradiated portion and scattered around. In the above method, since laser processing is performed while removing the decomposed material in the vicinity of the irradiated portion, adhesion of the decomposed material on the processed surface side of the workpiece can be suppressed and surface contamination can be reduced. .

  The suction removal is preferably performed from the rear with respect to a direction coaxial with the irradiation direction of the laser beam or a progress direction of processing by the laser beam. For example, when cutting the workpiece by fixing the workpiece on the stage and scanning the laser beam, or by scanning the stage with the laser beam fixed, the decomposed product is processed in the processing direction ( Scattered backward in the scanning direction). Accordingly, by performing suction removal from the rear in the direction coaxial with the laser light irradiation direction or the processing direction of the laser light as in the above method, the decomposition product can be removed more effectively. .

  It is preferable that gas is blown to the irradiated portion or the vicinity thereof to diffuse in the direction of removing the decomposed product by suction. Thereby, the efficiency of suction removal of the decomposed product can be improved, and contamination on the processed surface side of the workpiece can be further reduced.

  It is preferable to use compressed air as the gas.

  As the workpiece, a sheet material, a circuit board, a semiconductor wafer, a glass substrate, a ceramic substrate, a metal substrate, a semiconductor laser light emitting or receiving element substrate, a MEMS substrate, a semiconductor package, cloth, leather, paper, or a single layer or multiple layers Any film material can be used. Even in the above-described various workpieces, decomposition products adhere to the processed surface side during laser processing, resulting in surface contamination. However, since the surface contamination can be reduced by the laser processing method of the present invention involving suction removal of the decomposed product, the present invention can be suitably applied to these various types of workpieces.

As the laser light, ArF excimer laser, KrF excimer laser, XeCl excimer laser, third harmonic or fourth harmonic of YAG laser, third harmonic or fourth harmonic of solid laser of YLF or YVO ₄ , Ti: S laser, semiconductor laser, fiber laser or carbon dioxide laser can be used.

  In order to solve the above problems, the laser processed product of the present invention is obtained by the laser processing method described above.

  In the laser processing method according to the present invention, the decomposition product generated during the laser light irradiation is performed while sucking and removing in the vicinity of the irradiated portion, so that the decomposition product does not adhere to the processed surface side of the workpiece. Thus, contamination of the processed surface can be reduced. As a result, it is possible to provide a laser processing method capable of performing laser processing with high production efficiency and easily.

  Furthermore, post-process such as wet desmear, for example, can be omitted for removal of decomposition products. In addition, there is no need for waste liquid treatment required in the post-process, which can contribute to reducing the environmental burden. In addition, since the adhesion of decomposition products can be reduced, it is possible to increase the power of the laser beam and improve the throughput.

  A laser processing method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram schematically showing the state of the laser processing method according to the present embodiment.

  In the laser processing method according to the present embodiment, as shown in FIG. 1, the decomposition product 4 generated when the workpiece 3 is irradiated with the laser beam 1 is sucked and removed using the suction nozzle 5. . The suction removal is preferably performed from the rear in the direction coaxial with the irradiation direction of the laser beam 1 or in the processing progress direction (scanning direction) by the laser beam 1. This is because the decomposition product 4 tends to scatter toward the rear in the scanning direction, and removal efficiency can be improved by performing suction removal from the above direction. The suction nozzle 5 is preferably moved at a similar speed in accordance with the scanning speed of the laser beam 1.

  The suction nozzle 5 is connected to, for example, a vacuum pump. However, the present invention is not particularly limited as long as the decomposition product 4 can be sucked, and various conventionally known ones can be used. The suction ability is preferably 100 L / min or more, and more preferably 300 L / min or more. If the suction capacity is less than 100 L / min, removal of the decomposed product 4 becomes insufficient, and surface contamination on the processed surface side of the workpiece 3 may not be suppressed. In addition, although the removal rate of the decomposition product 4 improves, so that suction capability is high, it is preferable that the upper limit of suction capability is generally 1000 L / min or less.

  Further, it is preferable that the gas 14 is blown to the irradiated portion or the vicinity thereof to diffuse in the direction in which the decomposed product 4 is removed by suction. More specifically, when laser processing is performed as shown in FIG. 1, the gas 14 is rearward in the processing direction, from the rear of the suction nozzle 5 toward the processing surface of the workpiece 3. Spray from the spray nozzle 6. Since the decomposed material 4 diffuses along the processed surface of the workpiece toward the rear with respect to the processing progress direction, the decomposed material 4 is directed to the suction nozzle 5 by blowing the gas 14 from the direction. To diffuse. Thereby, the removal efficiency of the decomposition product 4 can be improved. The gas 14 is not particularly limited, and examples thereof include compressed air, helium, nitrogen, and oxygen.

  In the present invention, it is not preferable to spray the assist gas on the laser processing portion coaxially with the laser beam 1. In the conventional laser processing method, for example, when processing with a carbon dioxide laser, an assist gas such as oxygen is blown from the same axis as the laser irradiation direction in order to promote the reaction. However, when the assist gas is sprayed, diffusion of the generated decomposition product is suppressed by the gas pressure and stays in the processed portion. As a result, the surface contamination of the workpiece may be promoted and adversely affected.

  The laser processing method of the present invention is applicable to all shape processing in which decomposition products are scattered, such as cutting processing, marking, drilling processing, grooving processing, scribing processing, or trimming processing. The present invention is preferably applied to cutting among these processes. Moreover, as a cutting process, it can apply to both a half cut and a full cut.

  The laser beam 1 is oscillated by a laser oscillator, reflected by a reflecting mirror in the transmission path, focused to the focal position by a condensing lens to a minimum, and irradiated from a processing nozzle 2 with high energy necessary for processing. Is done. The laser beam 1 is irradiated from the vertical direction to the workpiece 3 on the XY stage 7. At this time, when performing the cutting process, the laser irradiation position is moved along a predetermined processing line. Examples of the moving means of the laser beam 1 include known methods such as galvano scan and mask imaging processing in addition to the XY stage scan.

The laser beam 1 is not particularly limited and is appropriately selected depending on the processing method. The reaction process varies depending on the laser light source used. For example, an ArF excimer laser with an oscillation wavelength of 193 nm, a KrF excimer laser with 248 nm, a 308 nm XeCl excimer laser, a third harmonic of a 355 nm YAG laser, a fourth harmonic of 266 nm, Similarly, a Ti: S laser capable of absorbing light in the ultraviolet region via a multiphoton absorption process even with a laser having a wavelength of third, fourth harmonic, or 400 nm or more of a solid-state laser such as YLF or YVO ₄ Are processed by ablation etching, and a carbon dioxide laser with an oscillation wavelength of 9.3 mm or 10.6 mm is etched by a heat generation phenomenon using infrared absorption. Although the reaction process is different between the ablation by ultraviolet absorption and the thermal processing by infrared absorption, the decomposition products are generated in both processes. Therefore, the adhesion of the decomposition products to the surface becomes a problem in both processing processes.

  Examples of the workpiece 3 processed in the present invention include a polarizing film 15 shown in FIG. In the polarizing film 15, a pair of triacetyl cellulose (TAC) films 10 are bonded to both surfaces of a polyvinyl alcohol (PVA) film 11. Further, a separator 13 made of a PET film is provided on one TAC film 10 side with an acrylic pressure-sensitive adhesive layer 9 interposed therebetween. A surface protection film 12 is provided on the other TAC film 10 side. The surface protective film 12 has a configuration in which an acrylic pressure-sensitive adhesive layer 9 is provided on a polyethylene terephthalate (PET) film 8, and the acrylic pressure-sensitive adhesive layer 9 serves as a bonding surface with the other TAC film 10. .

  In addition to the polarizing film 15, the workpiece 3 can be applied without particular limitation as long as it can be processed by laser light. Specifically, for example, various sheet materials, circuit boards, semiconductor wafers, glass substrates, ceramic substrates, metal substrates, light emitting or light receiving element substrates such as semiconductor lasers, MEMS (Micro Electro Mechanical System) substrates, semiconductor packages, cloths, leathers Paper, single layer or multilayer film materials.

  Various sheet materials include, for example, polyimide resins, polyester resins, epoxy resins, urethane resins, polystyrene resins, polyamide resins, polycarbonate resins, and polyethylene and polypropylene resins containing fillers. Molecular film or non-woven fabric, those obtained by imparting physical or optical functions to the resin by stretching, impregnation, etc., metal sheets such as copper, aluminum, and stainless steel, or the above polymer sheet and / or metal sheet directly or The thing laminated | stacked through the adhesive agent etc. is mentioned.

  Examples of the circuit board include single-sided, double-sided or multilayer flexible printed boards, rigid boards made of glass epoxy, ceramic, metal core boards, etc., optical circuits formed on glass or polymers, or opto-electric hybrid circuit boards. .

  In addition, examples of the single layer or multilayer film material include various adhesive films and optical films.

  The laser processing conditions can be appropriately set according to the type of the workpiece 3 and the like. For example, when the laser processing method of the present invention is applied to cutting processing, the cutting speed (processing progress speed) can be appropriately set according to the physical properties of the workpiece 3. Since the present invention is a process using the laser beam 1, the cutting speed can be increased as compared with a conventional cutting process using a blade or a mold. When the polarizing film 15 is used as the workpiece 3, the cutting speed is preferably 10 to 300 m / min, and more preferably 50 to 150 m / min. When the cutting speed is less than 10 m / min, there is an inconvenience that productivity is lowered. On the other hand, if it exceeds 300 m / min, there is a disadvantage that the suction capacity of the pump cannot catch up with the amount of decomposed products generated per unit time.

  The condensing diameter of the laser beam 1 can be appropriately set according to the type of processing performed on the workpiece 3. In the case of the cutting process, the cutting width substantially coincides with the focused diameter of the laser beam 1. Therefore, the cutting width can be controlled by adjusting the condensing diameter. The condensed diameter (cutting width) is usually preferably 50 to 500 μm, and more preferably 100 to 300 μm. When the condensed diameter is less than 50 μm, the cutting speed may be reduced. On the other hand, when it exceeds 500 μm, the efficiency of taking out the product from the workpiece may be lowered.

  The power density of the laser beam 1 can be appropriately set according to the physical properties of the workpiece 3 and the cutting speed in the case of cutting. The light absorption rate of the workpiece 3 depends on the wavelength of the laser beam 1. The laser beam 1 can oscillate its wavelength from ultraviolet to near infrared by selecting an oscillation medium or crystal. Therefore, by using the laser beam 1 matched with the light absorption wavelength of the workpiece 3, it can be efficiently processed with a low power density. For example, when the workpiece 3 is the polarizing film 15, 50 to 700 W is preferable.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

Example 1
[Workpiece]
In this example, a polarizing film having the structure shown in FIG. 2 was used as a workpiece. That is, a surface protective film is provided on one surface of the PVA film, and a separator is laminated on the other surface via an acrylic pressure-sensitive adhesive layer (thickness: 24 μm). The surface protective film is made of a film provided by applying an adhesive layer on a PET substrate having a thickness of 38 μm. As the pressure-sensitive adhesive layer, an acrylic pressure-sensitive adhesive having a thickness of 24 μm was used. The separator is made of a PET film having a thickness of 38 μm. The PVA film has a thickness of about 22 μm.

[Laser irradiation device]
The used laser beam irradiation apparatus is as follows.
Laser light source: Carbon dioxide laser Laser wavelength: 10.6 mm
Maximum output: 250W

[Laser irradiation conditions]
The half cut process of the polarizing film was implemented on the following conditions. The suction nozzle was arranged in the direction opposite to the scanning direction of the laser beam. The suction nozzle was moved at the same speed as the scanning speed of the laser beam.
Power: 40W
Spot diameter: 120mm
Pulse width: 9ms
Repeat frequency: 20 kHz
Scanning speed: 400mm / s
Suction nozzle diameter: 4.5mmφ
Vacuum pump exhaust capacity: 500L / min
Distance between suction nozzle and irradiated part: 5mm
Cutting depth: 325 μm

  As a result of the half-cut processing, the decomposition product generated during the laser processing was drawn toward the suction nozzle, and was removed by suction without crawling the workpiece surface. The decomposition product residue in the vicinity of the half cut portion of the polarizing film remained attached within a range of 500 mm width or less with the half cut portion as the center.

(Example 2)
In this example, laser processing was performed in the same manner as in Example 1 except that cutting (full cut) processing was performed under the following processing conditions.

[Laser irradiation conditions]
Power: 100W
Spot diameter: 120mm
Pulse width: 20ms
Repeat frequency: 20 kHz
Scanning speed: 400mm / s
Suction nozzle diameter: 8mmφ
Vacuum pump exhaust capacity: 500L / min
Distance between suction nozzle and irradiated part: 5mm

  As a result of the cutting process, the decomposed material generated during the laser processing was drawn toward the suction nozzle, and was removed by suction without scratching the workpiece surface. The decomposition product residue in the periphery of the cut portion of the polarizing film remained attached within a range of 100 mm or less with the cut portion as the center.

(Example 3)
[Workpiece]
In this example, a polyimide film (trade name: Kapton, 125 mm thickness, manufactured by DuPont) was used as a workpiece.

[Laser irradiation device]
The same laser beam irradiation apparatus as that used in Example 1 was used.

[Laser irradiation conditions]
Under the following conditions, the polyimide film was cut (full cut). The suction nozzle was arranged in the direction opposite to the scanning direction of the laser beam. The suction nozzle was moved at the same speed as the scanning speed of the laser beam.

Power: 40W
Spot diameter: 120mm
Pulse width: 9 ms
Repeat frequency: 20 kHz
Scanning speed: 400mm / s
Suction nozzle diameter: 8mmφ
Vacuum pump exhaust capacity: 500L / min
Distance between suction nozzle and irradiated part: 5mm

  As a result of the cutting process, the decomposed material generated during the laser processing was drawn toward the suction nozzle, and was removed by suction without scratching the workpiece surface. The decomposition product residue around the cut portion of the polyimide film was not confirmed by an optical microscope.

(Comparative Example 1)
In this comparative example, the polarizing film was half cut in the same manner as in Example 1 except that the decomposed product was not removed by suction. As a result, it was confirmed that the decomposition product residue around the cut portion of the polarizing film adhered in a large amount over a range of 5 mm or more around the half cut portion.

It is the schematic for demonstrating the laser processing of the to-be-processed object which concerns on embodiment of this invention. It is sectional drawing which shows typically the polarizing film as the said to-be-processed object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser beam 2 Processing nozzle 3 Work piece 4 Decomposition thing 5 Suction nozzle 6 Spray nozzle 7 XY stage 8 Film 9 Acrylic adhesive layer 10 TAC film 11 Polyvinyl film 12 Surface protection film 13 Separator 14 Gas 15 Polarizing film ( Work piece)

Claims (2)

A laser processing method for processing a workpiece by irradiating a laser beam,
Decomposing products generated during the irradiation of the laser light, while removing the suction in the vicinity of the irradiated portion, the laser processing ,
The suction removal is performed using a suction nozzle from behind with respect to the processing direction of the laser beam,
Compressed air as a gas on the processing surface of the workpiece is blown from the back of the suction nozzle in the direction of processing, and diffused in the direction of sucking and removing the decomposition product,
As the workpiece, a sheet material, a circuit board, a semiconductor wafer, a glass substrate, a ceramic substrate, a metal substrate, a semiconductor laser light emitting or receiving element substrate, a MEMS substrate, a semiconductor package, cloth, leather, paper, or a single layer or multiple layers Of film material,
As the laser light, ArF excimer laser, KrF excimer laser, XeCl excimer laser, third harmonic or fourth harmonic of YAG laser, third harmonic or fourth harmonic of solid laser of YLF or YVO ₄ , Ti: A laser processing method using an S laser, a semiconductor laser, a fiber laser, or a carbon dioxide gas laser . A laser processed product obtained by the laser processing method according to claim 1 .

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