Machining process for a workpiece

Abstract

Method for machining a plate-shaped workpiece (11) comprising a layered body (17) containing metal, which is formed in a superimposed relationship with projected division lines (13), comprising the following steps: Holding one side of the workpiece (11) with the layered body (17) on a first holding table; then performing a dry etching on the workpiece (11) through a mask (25) arranged in areas which omit the projected parting lines (13) in order to form etched grooves (19a) in the workpiece (11) along the projected parting lines (13) in such a way that the layered body (17) is not removed; then holding the side of the workpiece (11) with the layered body (17) or a side of the workpiece (11) opposite its side with the layered body (17) on a second holding table; and then cutting the bottoms of the etched grooves (19a) with a cutting blade (10) to divide the workpiece (11) and the layered body (17) along the projected division lines (13); wherein the step of cutting the bottoms of the etched grooves (19a) includes the step of cutting the bottoms of the etched grooves (19a) while a cutting fluid 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 a layered body containing metal, which is 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 or the like, 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 parting lines on wafers, as described above (see, for example, Japanese patent applications JP H06-349926A and JP 2005-21940A). The TEGs at the projected parting 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 evaluations and is no longer needed, it can be removed when the wafer is divided into component chips. JP 2016-54182A discloses a machining process for a plate-shaped workpiece containing a layered body containing metal. In this machining process, the metal is cut.

[0004] JP 2017- 41 525 A discloses a processing method for wafers in which the wafer is broken by means of a doctor blade in order to divide it. PRESENTATION OF THE INVENTION

[0005] 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 coated 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.

[0006] Therefore, an objective of the present invention is to provide a method for machining a plate-shaped workpiece comprising a layered body containing metal formed in a superimposed relationship to projected division lines at an increased speed, while maintaining the quality of the machining of the workpiece.

[0007] In accordance with an aspect of the present invention, a method for machining a plate-shaped workpiece containing a layered body formed in a superimposed relationship with projected parting lines comprises the steps of holding one side of the workpiece with a layered body on a first holding table, then performing dry etching on the workpiece through a mask arranged in areas that omit projected parting lines, thereby forming etched grooves in the workpiece along the projected parting line, such that the layered body is not removed, then holding the side of the workpiece with a layered body, or a side of the workpiece opposite the side of the layered body, on a second holding table, and then cutting the bottoms of the etched grooves with a cutting blade.to divide the workpiece and to divide the layered body along the projected parting lines, the step of cutting the bottoms of the etched grooves including the step of cutting the bottoms of the etched grooves while a cutting fluid containing an organic acid and an oxidizing agent is supplied to the workpiece.

[0008] In the above aspect of the present invention, the cutting blade should preferably have a smaller thickness than the width of the etched grooves.

[0009] According to the method in accordance with one aspect of the present invention, the cutting fluid, which contains an organic acid and an oxidizing agent, is supplied to the cutting blade and the workpiece when the layered body containing metal is cut by the cutting blade. The organic acid and the oxidizing agent effectively modify the metal contained in the layered body, thereby reducing the ductility of the metal as the cutting blade cuts the layered body. This prevents the metal from forming burrs, even when the workpiece is machined at a higher speed. In other words, the speed at which the workpiece is machined can be increased while maintaining the quality of the machining.

[0010] According to the method in accordance with the present invention, since dry etching is performed on the workpiece through the mask provided in areas except for the projected parting lines, the workpiece is processed simultaneously along all the projected parting lines to form etched grooves in it, thereby reducing the time required to process the workpiece per projected parting line while maintaining the quality of the workpiece processing, particularly when the number of projected parting lines in the workpiece is large. In other words, the speed at which the workpiece is processed can be increased while maintaining the quality of the workpiece processing.

[0011] 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 a perspective view that schematically shows the workpiece to which a dividing band etc. is attached; Fig. 2A is a partial side view, partly in cross-section, showing a training step of a mask of a machining process for a workpiece according to an embodiment of the present invention; Fig. 2B is a top view in cross-section, schematically showing a device for dry etching; Fig. 3A is a partial side view, partly in cross-section, which schematically shows the workpiece with etched grooves that were formed in it in one step of the dry etching machining process for a workpiece; Fig. 3B is a side view, partly in cross-section, showing a second holding step of the machining process for a workpiece; Fig. Figure 4 is a partial side view, partly in cross-section, showing a cutting step of the machining process for a workpiece; and Fig. Figure 5 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

[0012] A method for machining a workpiece according to an embodiment of the present invention is described below with reference to the accompanying figures. The method for machining a workpiece according to the present invention is also referred to as a "workpiece machining method" and is a method for machining a plate-shaped workpiece comprising a layered body containing metal, formed in a superimposed relationship to projected parting lines, and includes a forming step for a mask (see Figure 1). Fig. 2 A), a first holding step (see Fig. 2B), a step towards dry etching (see Fig. 3A), a second holding step (see Fig. 3B) and a cutting step (see Fig. 4).

[0013] In the mask formation step, a mask is formed on the side of the workpiece opposite the layered body. The mask is formed in areas that omit the projected parting lines. In the first holding step, the side of the workpiece with the layered body is held in an electrostatic clamping device (first holding table) for dry etching, so that the mask is exposed. In the dry etching step, dry etching is performed on the workpiece through the mask, forming etched grooves in the workpiece along the projected parting lines in such a way that the layered body remains. In the second holding step, the side of the workpiece with the layered body is held in the clamping table of a cutting device (second holding table).In the cutting step, the bottoms of the etched grooves are cut by a cutting blade, while a cutting fluid containing an organic acid and an oxidizing agent is supplied to the workpiece, so that the workpiece and the layered body are separated along the projected parting lines. The machining process for a workpiece according to the present embodiment is described in detail below.

[0014] Fig. 1A is a perspective view that schematically shows a workpiece 11 as an example to be machined by the machining process for a workpiece according to the present embodiment. As in Fig. As shown in Figure 1A, the workpiece 11 includes a disk-shaped wafer made of a semiconductor material such as silicon (Si) or the like, and one surface side of it 11a is divided into a central component area and an outer circumferential border area surrounding the central component area.

[0015] 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. A layered body 17, containing metal, is provided on a rear side 11b of the workpiece 11. The layered body 17 comprises a multilayer metal film of titanium (Ti), nickel (Ni), gold (Au), etc., having a thickness of approximately several micrometers, and serves as an electrode or the like. The layered body 17 is also formed in regions that overlap with the projected division lines 13.

[0016] According to the present embodiment, the workpiece 11 is shown, comprising a disk-shaped wafer made of 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 body 17 are not limited to specific types, quantities, shapes, structures, sizes, arrangements, etc. For example, a packaged substrate on which a layered body 17, serving as an electrode, is formed along the projected division lines 13 can be used as the workpiece 11.

[0017] Fig. Figure 1B is a perspective view that schematically depicts the workpiece 11 to which the dividing strip 21 is attached. As in Fig. As shown in Figure 1B, before the machining process is carried out on a workpiece according to the present embodiment, the dividing strip 21, which has a larger diameter than the workpiece 11, is attached to the rear side 11b, i.e., in the layered body 17 of the workpiece 11. The annular frame 23 is fixed to an outer circumferential section of the dividing strip 21.

[0018] The workpiece 11 is thus supported on the annular frame 23 by the dividing band 21. Although an example in which the workpiece 11 is supported on the annular frame 23 by the dividing band 21 is described below in the present embodiment, the workpiece 11 can be machined without using the dividing band 21 and the frame 23.

[0019] In the machining process for a workpiece according to the present embodiment, a training step for a mask is carried out in order to form a mask for dry etching in a covering relationship with the surface side 11a of the workpiece 11, which is opposite the layered body 17. Fig. 2A is a partial lateral view, partly in cross-section, which represents the training step for a mask, showing a mask 25 that is formed on the surface side 11a of the workpiece 11.

[0020] Mask 25 is formed by a process such as photolithography or the like and exhibits at least a certain degree of resistance to subsequent dry etching. As in Fig. As shown in Figure 2A, the mask 25 is designed to expose the projected division lines 13. In other words, the mask 25 is formed in areas that omit the projected division lines 13.

[0021] The training step for a mask is followed by the first holding step to hold the workpiece 11 on an electrostatic clamping device (first holding table) of a device for dry etching (device for plasma etching). Fig. Figure 2B is a top view in cross-section, schematically showing a device for dry etching (plasma etching device) 22. The device 22 for dry etching includes a vacuum chamber 24, which has a processing area formed within it. The vacuum chamber 24 includes a side wall with an opening 24a through which the workpiece 11 can be loaded into and removed from the processing area in the vacuum chamber 24.

[0022] A flap 26 is provided outside the opening 24a to selectively open and close the opening 24a. The flap 26 is connected to an opening / closing mechanism (not shown) that selectively opens and closes the flap 26. When the flap 26 is open to release the opening 24a, the workpiece 11 can be loaded into or removed from the processing area in the vacuum chamber 24 through the opening 24a.

[0023] The vacuum chamber 24 includes a lower wall with an evacuation opening 24b formed therein, which is connected to an evacuation unit 28 such as a vacuum pump or the like. A lower electrode 30 is arranged in the processing space within the vacuum chamber 24. The lower electrode 30 is plate-shaped, made of an electrically conductive material, and electrically connected to a high-frequency power source 32 located outside the vacuum chamber 24.

[0024] An electrostatic clamping device 34 is arranged on an upper surface of the lower electrode 30. The electrostatic clamping device 34 has several electrodes 36a and 36b, which are insulated from each other, for example. The electrostatic clamping device 34 attracts and holds the workpiece 11 under electrical forces generated between electrodes 36a and 36b and the workpiece 11. According to the present embodiment, the electrostatic clamping device 34 is arranged such that electrode 36a can be connected to the positive terminal of the direct current (DC) power source 38a, whereas electrode 36b can be connected to the negative terminal of the DC power source 38b.

[0025] An upper electrode 40, which has a disc shape and is made of electrically conductive material, is mounted on a ceiling wall of the vacuum chamber 24 with an insulator between the electrode and the upper electrode. The upper electrode 40 has several gas injection holes 40a formed on its lower surface, which are connected to a gas supply source 42 via a gas supply hole 40b formed on its upper surface. Therefore, the gas supply source 42 can supply a material gas for dry etching through the gas supply hole 40b and the gas injection holes 40a into the processing area within the vacuum chamber 24. The upper electrode 40 is electrically connected to a high-frequency power source 44 located outside the vacuum chamber 24.

[0026] In the first holding step, the opening / closing mechanism lowers the flap 26, exposing the opening 24a. The workpiece 11 is then loaded through the exposed opening 24a into the processing chamber in the vacuum chamber 24 and positioned against the electrostatic clamping device 34. Specifically, the dividing strip 21, which adheres to the rear side 11b, i.e., the layered body 17 of the workpiece 11, is held in contact with the upper surface of the electrostatic clamping device 34. The electrostatic clamping device 34 is then energized to attract and hold the workpiece 11, while the mask 25 on the surface 11a of the workpiece remains exposed.

[0027] After the first holding step, the dry etching step is performed to carry out dry etching (plasma etching) on ​​the workpiece 11 through the mask 25 in order to form etched grooves in the workpiece along the projected parting lines 13 in such a way that the layered body 17 is not removed. The dry etching step is also carried out using the dry etching device 22.

[0028] In particular, the opening / closing mechanism lifts the flap 26, thereby closing the processing chamber in the vacuum chamber 24. The evacuation unit 28 is then activated to evacuate the processing chamber. While the material gas for dry etching is supplied from the gas supply source 42 at a predetermined flow rate, the high-frequency power sources 32 and 34 appropriately supply high-frequency electrical power to the lower electrode 30 and the upper electrode 40, respectively, thereby forming a plasma containing radicals, ions, etc., between the lower electrode 30 and the upper electrode 40.

[0029] The sections of the surface 11a of the workpiece 11 that are not covered by the mask 25, i.e., the projected parting lines 13, are exposed to the plasma that processes the workpiece 11. The material gas for dry etching, supplied by the gas supply source 42, can be suitably configured depending on the material, etc., of the workpiece 11. Consequently, when the workpiece 11 is dry etched, etched grooves 19a are formed in the workpiece 11 to a depth that ends just above the layered body 17, i.e., does not reach it. In other words, the etched grooves 19a in the workpiece are formed in such a way that they do not remove the layered body 17.

[0030] Fig. Figure 3A is a partial side view, partly in cross-section, schematically showing the workpiece 11 with the etched grooves 19a formed in it during the dry etching step. In a dry etching process carried out under conditions such that a suitable section of the workpiece 11 is etched away, the layered body 17 containing metal is not substantially removed. Therefore, even if the dry etching step is carried out for a relatively long period of time, the layered body 17, which overlaps at the projected parting lines 13, will not be etched away.

[0031] In the dry etching step, where the etched grooves 19a are formed by machining the workpiece 11 simultaneously along a projected division line 13, the time required to machine the workpiece 11 per projected division line 13 is reduced, while maintaining the machining quality of the workpiece 11, especially when the number of projected division lines 13 on the workpiece 11 is large. After the dry etching step, the mask 25 is removed by ashing or the like.

[0032] After the dry etching step, the second holding step is performed to hold the workpiece 11 on a clamping table (second holding table) of a cutting device. Fig. Figure 3B is a side view, partially in cross-section, depicting the second holding step. The second holding step is performed using a cutting device 2, which is located in Fig. The process is carried out as shown in Figure 3B, for example. The cutting device 2 includes a clamping table (second holding table) 4 for holding the workpiece 11 under suction.

[0033] The clamping table 4 is connected to a rotary actuator (not shown), such as a motor or the like, so that it can be rotated about an axis substantially parallel to a vertical direction. The clamping table 4 is arranged above the machining feed mechanism (not shown), which moves the clamping table 4 in a machining feed direction.

[0034] 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 indexing strip 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.

[0035] When a negative pressure from the suction source is applied to the holding surface 4a, the workpiece 11 is held against the clamping table 4 by suction. Several clamps 6 for securing the annular frame 23 are provided on an outer circumferential area of ​​the clamping table 4.

[0036] In the second holding step, the dividing strip 21, which adheres to the rear side 11b 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 dividing strip 21. Simultaneously, the frame 23 is secured by the clamps 6. The workpiece 11 is therefore securely held by the clamping table 4 and the clamps 6, with the layered body 17 exposed at the top on its surface 11a.

[0037] After the second holding step, the cutting step is performed to cut the bottoms of the etched grooves 19a in order to divide the workpiece 11 and the layered body 17 along the projected division lines 13. Fig. Figure 4 is a partial side view, partly in cross-section, showing the cutting step. The cutting step is also carried out using the cutting device 2. As in Fig. As shown in Figure 4, the cutting device 2 further includes a cutting unit 8, which is arranged above the clamping table 4.

[0038] The cutting unit 8 includes a spindle (not shown) that acts as a shaft, oriented essentially perpendicular to the machining feed direction. An annular cutting blade 10, formed from a bonding agent 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.

[0039] The cutting blade 10 at one end of the spindle is rotatable about its own axis by forces transmitted by the rotary actuator. In the cutting step according to the present embodiment, the cutting blade 10 is narrower than the width of the etched grooves 19a.

[0040] The spindle is supported by a movement mechanism (not shown) that can move the cutting blade 10 in the index feed direction perpendicular to the machining feed direction and in a vertical direction perpendicular to both the machining feed direction and the index feed direction. A pair of nozzles 12 is arranged on both sides of the cutting blade 10, which is consequently positioned between the nozzles 12. The nozzles 12 are arranged to supply cutting fluid 14 to the cutting blade 10 and the workpiece 11.

[0041] In the cutting step, the clamping table 4 is rotated about its own axis to align an etched target groove 19a (projected parting line 13) with the machining feed direction of the cutting device 2. The clamping table 4 and the cutting unit 8 are moved relative to each other to position the plane of the cutting blade 10 in alignment with an extension of the etched target groove 19a (projected parting line). The lower end of the cutting blade 10 is then moved to position it deeper than the lower surface of the layered body 17.

[0042] Then, while the cutting blade 10 is rotated about its own axis, the clamping table 4 is moved in the machining feed direction. Simultaneously, the nozzles 12 deliver the cutting fluid 14, which contains an organic acid and an oxidizing agent, to the cutting blade 10 and the workpiece 11. The cutting blade 10 moves into and along the etched target groove 19a and cuts the workpiece 11 and the layered body 17, thereby completely separating the workpiece 11 and the layered body 17 by forming a joint (slot) 19b in the layered body 17 along the etched target groove 19a.

[0043] The organic acid contained in the cutting fluid 14 modifies the metal in the layered body 17 to reduce its ductility. The oxidizing agent contained in the cutting fluid 14 facilitates the oxidation of the metal in the layered body 17 at its surface. As a result, the ductility of the metal in the layered body 17 is sufficiently reduced to increase the machinability of the workpiece 11.

[0044] 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.

[0045] 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.

[0046] 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'-diacetic acid, etc.

[0047] 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.

[0048] Examples of oxidizing agents that may be contained in the cutting fluid 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.

[0049] Furthermore, a corrosion inhibitor can be mixed into the cutting fluid 14. 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.

[0050] 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.

[0051] 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.

[0052] Furthermore, examples of 1,2,4-triazole derivatives that can be used as corrosion inhibitors 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.

[0053] The above process is repeated to cut and form grooves 11b along all the etched grooves 19a, after which the cutting step is complete. According to the present embodiment, as described above, the cutting fluid 14, which contains an organic acid and an oxidizing agent, is supplied to the workpiece 11 so that the layered bodies 17 containing the metal are separated by the cutting blade 10. The organic acid and the oxidizing agent effectively modify the metal formed in the coated bodies 17, thereby reducing the ductility of the metal as the cutting blade 10 separates the layered bodies 17. This prevents the metal from forming burrs, even when the workpiece 11 is machined at an increased speed.

[0054] According to the present embodiment, since the cutting blade 10, which has a lesser thickness than the width of the etched grooves 19a, is used, the cutting fluid 19 tends to accumulate between the sidewall surfaces of the etched groove 19a and the cutting blade 10. As a consequence, the layered body 19 can be supplied with a sufficient quantity of cutting fluid 14 to further increase the machinability of the workpiece 11.

[0055] In the machining process for a workpiece according to the present embodiment, as described above, the cutting fluid 14, which contains an organic acid and an oxidizing agent, is supplied to the cutting blade 10, and the workpiece 11 is fed to the cutting blade 10 while cutting the layered body 17 containing metal. The organic acid and the oxidizing agent effectively modify the metal contained in the layered body 17, thereby reducing the ductility of the metal as the cutting blade 10 cuts the layered body 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.

[0056] In the machining process for a workpiece according to the present embodiment, since dry etching is performed on the workpiece 11 through the mask 25, which is provided in the areas except for the projected division lines 13, the workpiece 11 can be machined simultaneously along all the projected division lines 13 to form the etched grooves 19a in it. This reduces the time required to machine the workpiece 11 per projected division line 13, while maintaining the quality of the machining of the workpiece 11, particularly if the number of projected division lines 13 on a workpiece 11 is large. In other words, the speed at which the workpiece 11 can be machined can be increased while maintaining the quality of the machining of the workpiece 11.

[0057] The present invention is not limited to the embodiment described above, but various changes and modifications can be made to it. For example, if the workpiece 11, in which the layered body 17 containing metal is machined on its rear side 11b in the embodiment described above, a workpiece in which a layered body containing metal is formed on its surface side can be machined. Such a workpiece can be a wafer or the like, in which layered bodies containing evaluation elements, referred to as TEGs (Test Element Groups) or the like, are superimposed at respective positions with projected division lines on a surface side of the wafer or the like.

[0058] In the embodiment described above, the cutting blade 10 cuts into the workpiece 11 from its surface side 11a. However, the cutting blade 10 can also cut into the workpiece 11 from its rear side 11b. In such a modification, it is necessary to detach the dividing belt 21 and then hold the surface side 11a of the workpiece 11 on a clamping table 4, with the rear side 11b of the workpiece 11 exposed at the top.

[0059] In the above cutting step, the cutting fluid is supplied by the nozzles 12, which are arranged on both sides of the cutting blade 10. However, the present invention is not limited to a specific nozzle configuration for supplying the cutting fluid 14. Fig. Figure 5 is a side view of a nozzle for supplying the cutting fluid 14 according to another embodiment of the present invention. As in Fig. Figure 5 shows a cutting unit 8 as a modification in addition to the cutting blade 10 and the pair of nozzles 12, a shower nozzle 16 which is arranged in front of or behind the cutting blade 10.

[0060] The nozzle 16 facilitates the supply of the cutting fluid 14 to the groove (slot) 19b for more efficient modification of the metal contained in the layered body 17. Specifically, the nozzle 16 has an ejection opening inclined downwards towards an area where the cutting blade 10 processes the workpiece 11, as shown in Fig. As shown in Figure 5, the joint 19b is supplied and filled with an increased amount of the cutting fluid 14 to modify the metal contained in the layered body 17 more efficiently. Although both nozzle 12 and nozzle 16 are shown in Fig. If nozzles 5 are used, nozzles 12 can be omitted and only nozzle 16 can be used alone.

Claims

[1] Method for machining a plate-shaped workpiece (11) comprising a layered body (17) containing metal, which is formed in a superimposed relationship with projected division lines (13), comprising the following steps: Holding one side of the workpiece (11) with the layered body (17) on a first holding table; then performing a dry etching on the workpiece (11) through a mask (25) arranged in areas which omit the projected parting lines (13) in order to form etched grooves (19a) in the workpiece (11) along the projected parting lines (13) in such a way that the layered body (17) is not removed; then holding the side of the workpiece (11) with the layered body (17) or a side of the workpiece (11) opposite its side with the layered body (17) on a second holding table; and then cutting the bottoms of the etched grooves (19a) with a cutting blade (10) to divide the workpiece (11) and the layered body (17) along the projected division lines (13); wherein the step of cutting the bottoms of the etched grooves (19a) includes the step of cutting the bottoms of the etched grooves (19a) while a cutting fluid containing an organic acid and an oxidizing agent is supplied to the workpiece (11). [2] Method according to claim 1, wherein the cutting blade (10) has a thickness that is less than the width of the etched grooves (19a).

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