Machining process for a workpiece

Abstract

Method for machining a plate-shaped workpiece (11) comprising layered bodies (17) containing metal on one surface side, which are formed in a superimposed relationship with projected division lines (13), comprising the following steps: Holding the surface side (11a) of the workpiece (11) on a holding table; then applying a laser beam (8a, 8b) having a wavelength that can be absorbed by the workpiece (11) to a rear side of it along the projected parting lines (13) to form laser-machined grooves (19a, 19c) in the workpiece (11) that terminate before the layered bodies (17); and then cutting the bottoms of the laser-machined grooves (19a, 19c) with a cutting blade (20) to divide the workpiece (11) together with the layered bodies (17) along the projected division lines (13); wherein the step of cutting the bottoms of the laser-machined grooves (19a, 19c) includes the step of cutting the bottoms of the laser-machined grooves (19a, 19c) while a cutting fluid (24) containing an organic acid and an oxidizing agent is supplied to the workpiece (11).

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to a machining method for a plate-shaped workpiece comprising layered bodies containing metal, which are formed in a superimposed relationship to projected division lines. Description of the state of the art

[0002] Electronic devices, typically mobile phones and personal computers, use component chips as essential components. These chips have electronic components such as circuits formed on them. A component chip is manufactured by dividing the face of a wafer, made of a semiconductor material such as silicon, into several areas with multiple projected division lines, also known as roads. The components are then formed in the respective areas, and the wafer is subsequently divided into individual component chips according to the component placement along the projected division lines.

[0003] In recent years, evaluation elements, often referred to as TEGs (Test Element Groups), have frequently been designed to evaluate the electrical properties of components along projected division lines on wafers, as described above (see, for example, Japanese patent applications JP H06-349926A and JP 2005-21940A). The TEGs at the projected division line on a wafer make it possible to maximize the number of component chips that can be fabricated from the wafer. After the TEG has performed its evaluations and is no longer needed, it can be removed when the wafer is divided into component chips.

[0004] US 2012 / 0286415A1 discloses a method for machining a plate-shaped workpiece which includes layered bodies on one surface side which are formed in a superimposed relationship with projected division lines, wherein the workpiece is held, a laser beam is applied to create holes and a cutting blade is used.

[0005] US 2015 / 0262881A1 discloses a method for machining a plate-shaped workpiece comprising layered metal bodies arranged in a superimposed relationship with projected parting lines, describing a cutting process. During the cutting process, a cutting fluid containing an organic acid and an oxidizing agent can be supplied to the workpiece.

[0006] US 9 130 057 B1 reveals a cutting blade. PRESENTATION OF THE INVENTION

[0007] When layered bodies containing metal, such as TEG, are cut and removed by a cutting blade formed from a binder with embedded abrasive grains, the metal within the layered bodies is elongated, creating protrusions called "burrs" due to contact with the cutting blade. If the cutting blade processes the wafer at an increased speed, more heat is generated, resulting in the formation of larger burrs. Therefore, depending on the processing method using the cutting blade, it is necessary to reduce the processing speed to maintain the quality of the wafer processing.

[0008] Therefore, an objective of the present invention is to provide a method for machining a plate-shaped workpiece comprising layered bodies containing metal, which are arranged in a superimposed relationship to projected division lines, at an increased speed, while maintaining the quality of the machining of the workpiece.

[0009] In accordance with one aspect of the present invention, a method for machining a plate-shaped workpiece comprising layered bodies containing metal on one face side, arranged in a superimposed relationship with the projected parting lines, is provided, comprising the steps of holding the face side of the workpiece on a holding table, then applying a laser beam having a wavelength that can be absorbed in the workpiece to the rear side thereof along the projected parting lines to form laser-machined grooves in the workpiece terminating in front of the layered bodies, and then cutting the bottoms of the laser-machined grooves with a cutting blade to divide the workpiece together with the layered bodies along the projected parting lines.wherein the step of cutting the bottoms of the laser-machined grooves includes the step of cutting the laser-machined grooves while a cutting fluid containing an organic acid and an oxidizing agent is supplied to the workpiece.

[0010] In the above aspect of the present invention, the method may further include a step for providing a protective element on the surface side of the workpiece prior to the step of cutting the bottoms of the laser-machined grooves, wherein the step of cutting the bottoms of the laser-machined grooves can be carried out when the surface side of the workpiece is held by the protective element provided thereon.

[0011] In the above aspect of the present invention, the cutting blade used in the step of cutting the bottoms of the laser-machined grooves should preferably have a thickness that is less than the width of the laser-machined grooves.

[0012] In the above aspect of the present invention, the method can further include the step of providing a protective element on the rear side of the workpiece, after the step of applying a laser beam and before the step of cutting the bottoms of the laser-machined grooves, wherein the step of cutting the bottoms of the laser-machined grooves can be carried out while the rear side of the workpiece is held by the protective element provided thereon.

[0013] According to the method in accordance with the present invention, the cutting fluid, which includes an organic acid and an oxidizing agent, is supplied to the workpiece as the layered metal-containing bodies are cut by the cutting blade. The organic acid and the oxidizing agent effectively modify the metal contained in the layered bodies, thereby reducing the metal's ductility as the cutting blade cuts the layered bodies. Consequently, the metal is prevented from forming burrs, even when the workpiece is machined at increased speeds. In other words, the machining speed can be increased while maintaining the quality of the workpiece machining.

[0014] The above and other aims, features and advantages of the present invention and the manner of realizing them will be made clearer and the invention itself best understood by studying the following description, the claims attached to it, with reference to the attached figures, which show a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE FIGURES Fig. 1A is a perspective view that schematically shows an example of a workpiece; Fig. 1B is an enlarged partial top view of a surface of the workpiece; Fig. 2A is a perspective view showing an application step for a first film of a machining process for a workpiece according to an embodiment of the present invention; Fig. 2B is a side view, partly in cross-section, showing a first holding step of the machining process for a workpiece; Fig. Figure 3 is a partial side view, partly in cross-section, showing a laser processing step of the machining process for a workpiece; Fig. 4A is a perspective view showing a second application step for a film in the machining process for a workpiece; Fig. 4B is a side view, partly in cross-section, showing a second holding step of the machining process for a workpiece; Fig. Figure 5 is a partial side view, partly in cross-section, representing a cutting step of the machining process for a workpiece; Fig. 6A is a partial side view, partly in cross-section, showing a laser processing step corresponding to a modification; Fig. 6B is a partial lateral view, partly in cross-section, showing a cutting step according to the modification; and Fig. Figure 7 is a side view of a nozzle for supplying a cutting fluid according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED VERSION

[0015] A machining method for a workpiece according to an embodiment of the present invention is now described below with reference to the accompanying figures. The method for machining a workpiece according to the present embodiment, also referred to as the "workpiece machining method," is a method for machining a plate-shaped workpiece comprising, on one surface side, layered bodies containing metal, which are formed in a superimposed relationship with projected parting lines, and includes a first application step for a film (first provisioning step for protective element) (see Fig. 2A), a first holding step (see Fig. 2B), a laser processing step (see Fig. 3), a second application step for a film (second provision step for protective element) (see Fig. 4A), a second holding step (see Fig. 4B) and a cutting step (see Fig. 5).

[0016] In the first application step for a film, a film (protective element) is applied to a surface of a workpiece that has layered bodies arranged on it. In the first holding step, the surface of the workpiece is held on a clamping table (first holding table) of a laser processing device. In the laser processing step, a laser beam with a wavelength that is absorbed by the workpiece is applied to a rear surface of the workpiece to create laser-cut grooves in the workpiece along the projected parting lines to a depth that ends before the layered bodies, i.e., does not reach them. In the second application step for a film, a film (protective element) is applied (provided) to the rear surface of the workpiece.In the second holding step, the rear side of the workpiece is held against the clamping table (second holding table) of a cutting device. During the cutting step, the bottoms of the laser-machined grooves are cut by a cutting blade, while a cutting fluid containing an organic acid and an oxidizing agent is supplied to the workpiece and the cutting blade, thereby dividing the workpieces and layered bodies along the projected parting line. The machining process for a workpiece according to the present embodiment is described below.

[0017] Fig. Figure 1A is a perspective view that schematically shows an exemplary workpiece 11 which is to be machined in the machining process for a workpiece according to the present embodiment, and Fig. 1B is an enlarged partial top view of a surface 11a of the workpiece 11. As in Fig. As shown in Figure 1A, the workpiece 11 comprises a disk-shaped wafer formed from a semiconductor material such as silicon (Si) or the like, and the surface 11a thereof is divided into individual component areas and an outer circumferential border area surrounding the central component area. The central component area is further divided into several regions by a grid of projected division lines or roads 13, with components 15 such as ICs (integrated circuits) or the like being formed in the respective regions. As shown in Fig. Figure 1B shows several layered bodies 17 containing metal, arranged along the projected division lines 13. The layered bodies 17 are provided as evaluation elements, also called, for example, TEG (test element group).

[0018] According to the present embodiment, the workpiece 11 is shown to comprise a disk-shaped wafer formed from a semiconductor such as silicon or the like. However, the workpiece 11 is not limited to specific materials, shapes, structures, sizes, etc. Similarly, the components 15 and the layered bodies 17 are not limited to a specific type, quantity, shapes, structures, sizes, arrangements, etc. For example, a packaged substrate in which layered bodies 17 serve as electrodes formed along projected division lines 13 can be used as the workpiece 11.

[0019] In the processing device for a workpiece according to the present embodiment, the first application step for a film (first provision step for a protective element) is carried out in order to apply (provide) a film (protective element) to the surface side 11a of the workpiece 11. Fig. 2A is a perspective view showing the first step in applying a film. In the first step of applying a film, as shown in Fig. As shown in Figure 2A, a first film (protective element) 21, made of plastic and larger in diameter than the workpiece 11, is attached to the surface 11a of the workpiece 11. An annular frame 23 is fixed to the outer circumferential section of the film 21.

[0020] The workpiece 11 is therefore supported on the annular frame 23 by the film 21. Although an example in which the workpiece 11, supported on an annular frame 23 by the film 21, is machined is described below in the present embodiment, the workpiece 11 can also be machined without using the film 21 and the frame 23. In this case, the first application step for a film can be omitted. Instead of the plastic film 21, a wafer equivalent to the workpiece 11 or another substrate can be applied to the workpiece 11 as a protective element.

[0021] The first application step for a film is followed by the first holding step to hold the workpiece 11 on a clamping table (first holding table) of a laser processing device. Fig. 2B is a side view, partially in cross-section, which represents the first holding step. The first holding step is performed using a laser processing device 2, which is in Fig. The process shown in Figure 2B is carried out as an example. The laser processing device 2 includes a clamping table (first holding table) 4 for holding the workpiece 11 under suction.

[0022] The clamping table 4 is coupled to a rotary actuator (not shown), such as a motor or the like, for rotation about an axis substantially parallel to a vertical direction. The clamping table 4 is arranged above a motion mechanism (not shown) that moves the clamping table 4 in a machining feed direction (first horizontal direction) and an indexing feed direction (second horizontal direction).

[0023] The clamping table 4 has an upper surface, part of which serves as a holding surface 4a for holding the workpiece 11, i.e., the film 21, under suction. The holding surface 4a is connected to a suction source (not shown) via a suction channel (not shown) formed in the clamping table 4. When a negative pressure from the suction source is applied to the holding surface 4a, the workpiece 11 is held under suction against the clamping table 4. Several clamps 6 for securing the annular frame 23 are provided on the outer circumferential area of ​​the clamping table 4.

[0024] In the first holding step, the film 21, which adheres to the surface 11a of the workpiece 11, is held in contact with the holding surface 4a of the clamping table 4, and a negative pressure from the suction source is applied to the film 21. Simultaneously, the frame 23 is secured by the clamps 6. The workpiece 11 is thus held by the clamping table 4 and the clamps 6 with its rear side 11b facing upwards.

[0025] After the first holding step, the laser processing step is performed to apply a laser beam 11 from the rear side 11b to create laser-machined grooves in the workpiece 11 along the projected parting lines 13 to a depth that stops above the layered bodies 17, i.e., does not reach them. The laser processing step is also performed using the laser processing device 2. Fig. Figure 3 is a partial side view, partly in cross-section, depicting the laser processing step. As in Fig. Figure 3 shows that the laser processing device 2 also includes an irradiation unit 8 for a laser, which is arranged directly above the clamping table 4.

[0026] The irradiation unit 8 for a laser beam applies a pulsed laser beam 8a, which is generated and emitted by a laser oscillator (not shown), and focuses the pulsed laser beam 8a at predetermined positions in the workpiece 11. The laser oscillator is arranged such that it generates and emits the pulsed laser beam 8a, which has a wavelength that is absorbed by the workpiece 11, for example, a wavelength that can be absorbed by the workpiece 11 or a wavelength that can be easily absorbed by the workpiece 11.

[0027] In the laser processing step, the clamping table 4 is rotated about its axis to align a projected target division line 13 with the processing feed direction of the laser processing device 2. Furthermore, the clamping table 4 is moved to align the irradiation unit 8 for a laser beam with the extent of the projected target division line 13. The position of the projected target division line 13 can be confirmed from the rear side 11b using a camera, for example, one that detects in an infrared range.

[0028] Then, as in Fig. As shown in Figure 3, while the pulsed laser beam 8a is applied by the irradiation unit 8 to the exposed rear side 11b of the workpiece 11, the clamping table 4 is moved in the processing feed direction. The pulsed laser beam 8a is focused on the rear side 11b of the workpiece 11 or, for example, within the workpiece 11. The energy parameters of the pulsed laser beam 8a, i.e., the power, repetition frequency, etc., are adjusted within such a range that the pulsed laser beam 8a does not bisect the workpiece 11.

[0029] In this way, the pulsed laser beam 8a is applied to the workpiece along the projected target division lines 13 to form a laser-machined groove 19a in the workpiece 11 along the projected target division line 13 to a depth that stops above the layered body 17, i.e., does not reach it. The above process is repeated to form laser-machined grooves 19a in the workpiece 11 along all the projected division lines 13, whereupon the laser processing step is completed.

[0030] The laser processing step is followed by the second application step for a film (second provision step for a protective element) in order to apply (provide) a film (protective element) to the rear side 11b of the workpiece 11. Fig. 4A is a perspective view showing a second application step for a film. In the second application step for a film, as in Fig. As shown in Figure 4A, a film (protective element) 25, made of a plastic and with a diameter larger than the workpiece 11, is attached to the rear side 11b of the workpiece 11. An annular frame 27 is fixed to an outer circumferential section of the film 25.

[0031] The workpiece 11 is thus supported on the annular frame 27 by the film 25. Although an example in which the workpiece 11 is supported on the annular frame 27 by the film 25 is described in the following embodiment, the workpiece 11 can be processed without the film 25 and the frame 27. In this case, the second application step for a film can be omitted. Instead of the plastic film 25, an equivalent of the wafer can be attached to the workpiece 11, and a different substrate can be attached to the workpiece 11 as a protective element.

[0032] The second application step for a film is followed by the second holding step to hold the workpiece 11 on the clamping table (second holding table) of a cutting device. Fig. Figure 4B is a side view, partially in cross-section, showing the second holding step. Before the second holding step, the film 21 on surface side 11a and the frame 23 are removed. The second holding step is carried out, for example, using the cutting device 12, which is located in Fig. 4B is shown. The cutting device 12 includes a clamping table (second holding table) 14 for holding the workpiece 11 under suction.

[0033] The clamping table 14 is equipped with a rotary actuator (not shown), such as a motor or the like, for rotation about an axis substantially parallel to a vertical direction. The clamping table 14 is arranged above the machining feed mechanism (shown), which moves the clamping table 14 in a machining feed direction (first horizontal direction).

[0034] The clamping table 14 has an upper surface, part of which serves as a holding surface 14a for holding the workpiece 11, i.e., the film 25, under suction. The holding surface 14a is connected to a suction source (not shown) via a suction channel (not shown) formed in the clamping table 14. When negative pressure from the suction source is applied to the holding surface 14a, the workpiece 11 is held against the clamping table 14 under suction. Several clamps 16 for securing the annular frame 27 are provided on an outer circumferential area of ​​the clamping table 14.

[0035] In the second holding step, the film 25, which adheres to the rear side 11b of the workpiece 11, is held in contact with the holding surface 14a of the clamping table 14, and a negative pressure from the suction source is applied to the film 25. Simultaneously, the frame 27 is secured by the clamps 16. The workpiece 11 is thus held by the clamping table 14 and the clamps 16, with the layered bodies 17 exposed at the top on the surface side 11a.

[0036] After the second holding step, the cutting step is performed to cut the bottoms of the laser-machined grooves 19a in order to divide the workpiece 11 and to divide the layered bodies 17 along the projected division lines 13. Fig. Figure 5 is a partial side view, partly in cross-section, showing the cutting step. The cutting step is also carried out using the cutting device 12. As in Fig. As shown in Figure 5, the cutting device 12 further includes a cutting unit 18, which is arranged above the clamping table 14.

[0037] The cutting unit 18 includes a spindle (not shown) that acts as a shaft essentially perpendicular to the machining feed direction. An annular cutting blade 20, made of a binder with abrasive grains dispersed therein, is mounted at one end of the spindle. The other end of the spindle is coupled to a rotary actuator (not shown), such as a motor or the like. The cutting blade 20 at one end of the spindle is rotatable about its own axis by forces transmitted from the rotary actuator.

[0038] The spindle is supported by a movement mechanism (not shown) that moves the cutting blade 20 in an index feed direction (second horizontal direction) perpendicular to the machining feed direction and in a vertical direction. A pair of nozzles 22 is arranged on both sides of the cutting blade 20, which is consequently positioned between the nozzles 22, to supply a cutting fluid 24 to the cutting blade 20 in the workpiece 11.

[0039] In the cutting step, the clamping table 14 is rotated about its own axis to align a laser-machined target groove 19a (projected division line 13) with the machining feed direction of the cutting device 2. The clamping table 14 and the cutting unit 18 are moved relative to each other to align the plane of the cutting blade 20 with an extension of the laser-machined target groove 19a. The lower end of the cutting blade 20 is then moved to a position lower than the lower surface of the layered body 17.

[0040] Then, while the cutting blade 20 is rotated about its own axis, the clamping table 14 is moved in the machining feed direction. Simultaneously, the nozzles 22 deliver the cutting fluid 24, which contains an organic acid and an oxidizing agent, to the cutting blade 20 and the workpiece 11. The cutting blade 20 moves along the laser-machined target groove 19a and cuts into the layered body 17 of the workpiece 11, thereby cutting the bottom of the laser-machined target groove 19a and separating the workpiece 11 and the layered body 17, thus forming a groove (slot) 19b in width in the workpiece 11 into the layered body 17 along the laser-machined target groove 19a.

[0041] The organic acid contained in the cutting fluid 24 modifies the metal in the layered bodies 17 to reduce its ductility. The oxidizing agent contained in the cutting fluid 24 facilitates surface oxidation of the metal in the layered bodies 17. As a result, the ductility of the metal in the layered body 17 is sufficiently reduced to improve the machinability of the workpiece 11.

[0042] The organic acid contained in the cutting fluid 14 can, for example, be a compound having at least one carboxyl group and at least one amino group in its molecule. In this case, it is preferred that at least one of the amino groups is a secondary or tertiary amino group. Additionally, the compound used in the organic acid can have a substituent group.

[0043] Amino acids can be used as the organic acid. Examples of amino acids that can be used here include glycine, dihydroxyethylglycine, glycylglycine, hydroxyethylglycine, N-methylglycine, β-alanine, L-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-alloisoleucine, L-isoleucine, L-phenylalanine, L-proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine, L-thyroxine, L-tyrosine, 3,5-diiodo-L-tyrosine, β-(3,4-dihydroxyphenyl)-L-alanine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine. L-Lanthionine, L-Cystathionine, L-Cystine, L-Cystic acid, L-Glutamic acid, L-Aspartic acid, S-(Carboxymethyl)-L-Cysteine, 4-Aminobutyric acid, L-Asparagine, L-Glutamine, Azaserine, L-Canavanine, L-Citrulline, L-Arginine, δ-Hydroxy-L-Lysine, Creatine, L-Kynurenine, L-Histidine, 1-Methyl-L-Histidine, 3-Methyl-L-Histidine, L-Tryptophan, Actinomycin C1, Ergothioneine, Apamin, Angiotensin I, Angiotensin II, Antipain, etc.Among others, glycine, L-alanine, L-proline, L-histidine, L-lysine, and dihydroxyethylglycine are particularly preferred.

[0044] Aminopolyacids can also be used as the organic acid. Examples of aminopolyacids that can be used here include iminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, hydroxyethyliminodiacetic acid, nitrilotrismethylenephosphonic acid, ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid, 1,2-diaminopropanetetraacetic acid, glycoletherdiaminetetraacetic acid, transcyclohexanediaminetetraacetic acid, ethylenediamineorthohydroxyphenylacetic acid, ethylenediaminedisuccinic acid (SS isomer), β-alaninediaacetic acid, N-(2-carboxyatoethyl)-L-aspartic acid, N-N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diaacetic acid, etc.

[0045] Furthermore, carboxylic acids can be used as organic acids. Examples of carboxylic acids that can be used here include saturated carboxylic acids such as formic acid, glycolic acid, propionic acid, acetic acid, butyric acid, valeric acid, caproic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, malic acid, succinic acid, pimelic acid, mercaptoacetic acid, glyoxylic acid, chloroacetic acid, pyruvic acid, acetoacetic acid, etc.; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, mesaconic acid, citraconic acid, aconitic acid, etc.; and cyclic unsaturated carboxylic acids such as benzoic acid, toluic acid, phthalic acid, naphthoic acids, pyromellitic acid, naphthalic acid, etc.

[0046] Examples of oxidizing agents that may be contained in the cutting fluid 24 include hydrogen peroxide, peroxides, nitrates, iodates, periodates, hypochlorites, chlorites, chlorates, perchlorates, persulfates, dichromates, permanganates, cerates, vanadates, ozonated water, silver(II) salts, iron(III) salts, and their organic complex salts.

[0047] Furthermore, a corrosion inhibitor can be mixed into the cutting fluid 24. Mixing in the corrosion inhibitor prevents corrosion (elution) of the metal contained in the workpiece 11. A heterocyclic ring compound having at least three nitrogen atoms in its molecule and a fused ring structure, or a heterocyclic aromatic ring compound having at least four nitrogen atoms in its molecule, is preferably used as the corrosion inhibitor. The aromatic ring compound preferably comprises a carboxyl group, sulfo group, hydroxy group, or alkoxy group. Specifically preferred examples of the aromatic ring compound include tetrazole derivatives, 1,2,3-triazole derivatives, and 1,2,4-triazole derivatives.

[0048] Examples of tetrazole derivatives that can be used as corrosion protection include those that have no substituent group on the nitrogen atoms forming the tetrazole ring and that have a substituent group inserted at the 5-position of the tetrazole selected from the group consisting of a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group, or an alkyl group substituted with at least one substituent group selected from the group consisting of a hydroxy group, a carboxyl group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group.

[0049] Examples of 1,2,3-triazole derivatives that can be used as corrosion inhibitors include those that have no substituent group on the nitrogen atoms forming the 1,2,3-triazole ring and that have a substituent group inserted at the 4-position and / or the 5-position of the 1,2,3-triazole, selected from the group consisting of a hydroxy group, a carboxyl group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group, or an alkyl or aryl group substituted with at least one substituent group selected from the group consisting of a hydroxy group, a carboxyl group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group.

[0050] Furthermore, examples of 1,2,4-triazole derivatives that can be used as corrosion protection include those that do not have a substituent group on the nitrogen atoms forming the 1,2,4-triazole ring and that, inserted at the 2-position and / or the 5-position of the 1,2,4-triazole, have a substituent group selected from the group consisting of a sulfo group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group, or an alkyl or aryl group substituted with at least one substituent group selected from the group consisting of a hydroxy group, a carboxyl group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group.

[0051] The above process is repeated to cut the workpiece 11 along all the projected division lines 13, thereby completing the cutting step.

[0052] In the machining process for a workpiece according to the present embodiment, as described above, the cutting fluid 24, which contains an organic acid and an oxidizing agent, is supplied to the workpiece 11 during the cutting of the layered bodies 17. The organic acid and the oxidizing agent effectively modify the metal contained in the layered bodies 17, thereby reducing the ductility of the metal as the cutting blade 20 cuts the layered bodies 17. Consequently, the metal is prevented from forming burrs, even when the workpiece 11 is machined at an increased speed. In other words, the speed at which the workpiece 11 is machined can be increased while maintaining the quality of the machining of the workpiece 11.

[0053] The present invention is not limited to the embodiment described above, and various changes and modifications can be made within it. For example, the width of the laser-machined grooves formed in the laser processing step can be greater than the thickness of the cutting blade used in the cutting step. Conversely, the thickness of the cutting blade used in the cutting step can be less than the width of the laser-machined grooves formed in the laser processing step.

[0054] Fig. 6A is a side view, partly in cross-section, showing a laser processing step according to a modification, and Fig. 6B is a partial side view, partly in cross-section, showing a cutting step corresponding to a modification. As in Fig. As shown in Figure 6A, the laser processing step is carried out according to the modification using the same laser processing device 2 as in the embodiment above.

[0055] In the laser processing step according to the modification, the clamping table 4 is rotated about its own axis to align a projected target division line 13 with the processing feed direction of the laser processing device 2. Furthermore, the clamping table 4 is moved to align the irradiation unit 8 for a laser with the extent of the projected target division line 13.

[0056] Then, as in Fig. Figure 6A shows that when a pulsed laser beam 8b is applied from the laser irradiation unit 8 to the exposed rear side 11b of the workpiece 11, the clamping table 4 is moved in the machining feed direction. The pulsed laser beam 8b is focused on the rear side 11b of the workpiece 11 or, for example, within the workpiece 11. The energy parameters of the pulsed laser beam 8b, i.e., the power, repetition frequency, etc., are adjusted so that the pulsed laser beam 8b does not bisect the workpiece 11.

[0057] In this way, the pulsed laser beam 8b is applied to the workpiece 11 along all the projected target parting lines 13 to form laser-machined grooves 19c in the workpiece 11 along the projected target parting line 13 to a depth that ends above the layered body 17, i.e., does not reach it. During the laser processing step, the conditions under which the pulsed laser beam 8b is applied can be adjusted to form a laser-machined groove 19c with a width greater than the thickness of the cutting blade to be used in the subsequent step. The above process is repeated to form laser-machined grooves 19c in the workpiece 11 along all the projected parting lines 13, after which the laser processing step is completed according to the modification.

[0058] The laser processing step is followed by a second holding step, in which no application step for a second film is performed. According to the modification, the second holding step is carried out using the same cutting device 12 as in the embodiment described above. In this holding step, the film 21, which adheres to the surface 11a of the workpiece 11, is held in contact with the holding surface 14a of the clamping table 14, and negative pressure from the suction source is applied to the film 21. Simultaneously, the frame 23 is secured by the clamps 16. The workpiece 11 is therefore securely held with its rear side 11b facing upwards.

[0059] After the second holding step, the cutting step is performed. The cutting step according to the modification is also performed using the cutting device 12. However, according to the modification, the cutting step uses a cutting blade 20 which has a width smaller than that of the laser-machined grooves 19c.

[0060] First, the clamping table 14 is rotated about its own axis to bring a laser-machined target groove 19c (projected division line) 13 into contact with the machining feed direction of the cutting device 2. The clamping table 14 and the cutting unit 18 are moved relative to each other to align the plane of the cutting blade 20 with an extension of the laser-machined target groove 19. Then, the lower end of the cutting blade 20 is moved to a position lower than the lower surface of the layered body 17.

[0061] Subsequently, while the cutting blade 20 is rotated about its own axis, the clamping table 14 is moved in the machining feed direction. Simultaneously, the nozzles 22 supply a cutting fluid 24, containing an organic acid and an oxidizing agent, to the cutting blade 20 and the workpiece 11. The cutting blade 20 moves along the laser-machined target groove 19c and cuts into the workpiece 11, thereby cutting the bottom of the laser-machined groove 19c and completely separating the workpiece 11 and the layered body 17. This creates a groove (slot) 19c in the width of the workpiece 11 and forms the layered body 17 along the laser-machined target groove 19c.

[0062] The organic acid contained in the cutting fluid 24 modifies the metal in the layered body 17 to reduce its ductility. The oxidizing agent contained in the cutting fluid 24 facilitates the oxidation of the surface of the metal contained in the layered bodies 17. As a result, the ductility of the metal in the layered body 17 is sufficiently reduced to increase the machinability of the workpiece 11.

[0063] In the cutting step according to the modification, since the cutting blade 20, which has a smaller thickness than the width of the laser-machined grooves 19c, is used, the cutting fluid 24 tends to accumulate between the lateral wall surfaces of the laser-machined groove 19 and the cutting blade 20. As a consequence, the layered body 17 can be supplied with a sufficient quantity of cutting fluid 24 to further improve the machinability of the workpiece 11.

[0064] In the modifications described above, the second holding step and the cutting step are performed without applying a second film. However, the application step for a second film can be performed, and then the second holding step and the cutting step can be carried out. In such a case, the rear side 11b of the workpiece 11 is held against the clamping table 14, and the cutting blade cuts into the surface side 11a. Furthermore, in the embodiment described above, the second holding step and the cutting step can be performed without applying a second film.

[0065] In the above cutting step, the cutting fluid 24 is supplied by the nozzles 22, which are arranged on both sides of the cutting blade 20. However, the present invention is not limited to a specific nozzle configuration for supplying the cutting fluid 24. Fig. Figure 7 is a side view of a nozzle for supplying the cutting fluid 24 according to another mode of the present invention. As in Fig. As shown in Figure 7, a cutting unit 18 according to the modification includes, in addition to the cutting blade 20 and the pair of nozzles 22, a shower nozzle 26 which is arranged in front of or behind the cutting blade 20.

[0066] The nozzle 26 facilitates the supply of the cutting fluid 24 to the joint (slot) 19b or 19d for more effective modification of the metal contained in the layered body 17. In particular, the nozzle 26 has an ejection opening inclined downwards towards an area where the cutting blade 20 processes the workpiece 11, as shown in Fig. 7 shown, so that the joint 19b or 19d can be supplied and filled with an increased amount of the cutting fluid 24 for effective modification of the metal contained in the layered body 17, which is preferred. Although both nozzles 22 and nozzle 26 in Fig. If nozzles 22 and 7 are used, nozzles 22 can be omitted and only nozzle 26 can be used.

Claims

[1] Method for machining a plate-shaped workpiece (11) comprising layered bodies (17) containing metal on one surface side, which are formed in a superimposed relationship with projected division lines (13), comprising the following steps: Holding the surface side (11a) of the workpiece (11) on a holding table; then applying a laser beam (8a, 8b) having a wavelength that can be absorbed by the workpiece (11) to a rear side of it along the projected parting lines (13) to form laser-machined grooves (19a, 19c) in the workpiece (11) that terminate before the layered bodies (17); and then cutting the bottoms of the laser-machined grooves (19a, 19c) with a cutting blade (20) to divide the workpiece (11) together with the layered bodies (17) along the projected division lines (13); wherein the step of cutting the bottoms of the laser-machined grooves (19a, 19c) includes the step of cutting the bottoms of the laser-machined grooves (19a, 19c) while a cutting fluid (24) containing an organic acid and an oxidizing agent is supplied to the workpiece (11). [2] The method of claim 1, further comprising the following step: prior to the step of cutting the bottoms of the laser-machined grooves (19a, 19c), providing a protective element (21, 25) on the surface side of the workpiece (11); wherein the step of cutting the bottoms of the laser-machined grooves (19a, 19c) is carried out while the surface side of the workpiece (11) is held by the protective element (21, 25) provided thereon. [3] Method according to claim 1 or 2 wherein the cutting blade (20) used in the step of cutting the bottoms of the laser-machined grooves (19a, 19c) has a lesser thickness than the width of the laser-machined grooves (19a, 19c). [4] The method of claim 1, further comprising the following step: after the step of applying a laser beam (8a, 8b) and before the step of cutting the bottoms of the laser-machined grooves (19a, 19c), providing a protective element (21, 25) on the rear side of the workpiece (11); wherein the step of cutting the bottoms of the laser-machined grooves (19a, 19c) is carried out while the rear side of the workpiece (11) is held by the protective element (21, 25) provided on it.

Images