Method for processing a substrate

Abstract

To provide a substrate processing method capable of appropriately removing a burr from a periphery of a processing groove of a substrate in which a metal is formed in division schedule lines and improving work efficiency of burr removal when processing the substrate along the division schedule lines.SOLUTION: A method for processing a substrate 90 in which a metal is formed in division schedule lines along the division schedule lines includes a processing groove forming step and a burr removing step. The processing group forming step forms a processing groove 95 in the substrate 90 along the division schedule lines. The burr removing step brings an etchant 500 containing at least an oxidant and applied with ultrasonic vibration into contact with the substrate, modifies a metallic burr 96 generated around the formed processing groove 95 with an oxidant contained in the etchant 500, embrittles the burr by suppressing ductility, and removes the burr by ultrasonic vibration after performing the processing groove forming step.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for processing a substrate in which a metal is formed on a planned division line along the planned division line.

Background Art

[0002] When forming a processing groove in a substrate including a metal part, a metal film, or wiring made of metal, burrs are generated in the metal part, and the burrs cause a short circuit between the terminals of the chip or fall on the bonding pad during handling of the workpiece, resulting in problems such as bonding failure. Therefore, a device has been proposed that injects high-pressure water from a nozzle onto the burrs to remove the burrs (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even when using the technology disclosed in Patent Document 1, it is difficult to appropriately remove the burrs around the processing groove. After forming the processing groove, a person inspects the processing groove to remove the burrs, which is inefficient.

[0005] Therefore, when processing a substrate in which a metal is formed on a planned division line along the planned division line, there is a problem of appropriately removing burrs from the substrate with full cut or half cut and improving the working efficiency of burr removal.

Means for Solving the Problems

[0006] The present invention for solving the above problems is a method for processing a substrate in which a metal is formed on a planned division line along the planned division line, and along the planned division line, on the substrate , from the surface side of the substrate a processing groove forming step of forming a processing groove, and after the implementation of the processing groove forming step, an etching solution containing at least an oxidizing agent and applied with ultrasonic vibration is onto the substrate contacted, and a burr removal step of modifying the burrs of the metal generated around the formed processing groove with the oxidizing agent contained in the etching solution to suppress ductility and make it brittle, and removing it by the ultrasonic vibration is provided , in the deburring step, an ultrasonic oscillator for applying the ultrasonic vibration is disposed on the upper surface of the bottom plate of the water tank in which the etching solution is stored, and the substrate is immersed in the etching solution with the ultrasonic oscillator facing the surface of the substrate. It is a method for processing a substrate.

[0007] In the method for processing a substrate according to the present invention, it is preferable that the etching solution further contains an organic acid.

[0008] In the method for processing a substrate according to the present invention, it is preferable that the etching solution further contains a corrosion inhibitor.

[0010] The etching solution further contains at least one of an organic acid or a corrosion inhibitor. In the burr removal step, it is preferable that the rate at which the burrs are etched is controlled by the composition ratio of the etching solution containing at least one of the oxidizing agent and the organic acid or the corrosion inhibitor.

Advantages of the Invention

[0011] The method for processing a substrate according to the present invention for processing a substrate in which a metal is formed on a planned division line along the planned division line includes a processing groove forming step of forming a processing groove on the substrate along the planned division line, and after the implementation of the processing groove forming step, contacting an etching solution containing at least an oxidizing agent and applied with ultrasonic vibration, and modifying the burrs of the metal generated around the formed processing groove with the oxidizing agent contained in the etching solution to suppress ductility and make it brittle, and removing it by ultrasonic vibration. By providing a burr removal step, burrs can be removed well, and the working efficiency of burr removal can be improved.

[0012] By making the etching solution used in the burr removal step contain an organic acid in addition to an oxidizing agent, it becomes possible to increase the effect of etching for burr removal.

[0013] By making the etching solution used in the burr removal step contain a corrosion inhibitor in addition to an oxidizing agent, it becomes possible to delay unnecessary etching of the chip on the device surface.

[0014] In the burr removal step, by immersing a substrate with processed grooves or a plurality of chips separated by the processed grooves in a water tank having an ultrasonic oscillator that stores the etching solution and applies ultrasonic vibration, it becomes possible to perform burr removal well in a short time.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0016] For example, the substrate 90 shown in FIG. 1, which is to be subjected to dicing, is, for example, a QFN (Quad Flat Non-leaded package) substrate. The substrate 90 has a frame plate 900 with a rectangular outer shape. On the surface 901 of the substrate 90 shown in FIG. 1, a plurality (three in the illustrated example) of device regions 902 that will become individual chips 909 equipped with devices by being divided are formed side by side in the longitudinal direction of the substrate 90. Each device region 902 is surrounded by its periphery by an end material portion 903 that is fragmented and discarded.

[0017] The device regions 902 are partitioned by a plurality of planned dicing lines 904 that are orthogonal to each other. On the planned dicing lines 904, metals 905 that constitute a plurality of electrode pads and the like connected to respective devices (not shown) are disposed. The metals 905 are insulated from each other by a mold resin (not shown) on the frame plate 900. Then, the substrate 90 is divided into chips 909 including a mold resin that seals a device (not shown) and a plurality of cut metals 905 by cutting the plurality of metals 905 at the center along the planned dicing lines 904. Note that an oxide film such as SiO2 with a thickness in the order of μm or a resin film may be formed as a device protection film in the device regions 902.

[0018] For example, as shown in FIG. 2, the back surface 907 (see FIG. 2) of the substrate 90 is adhered to the adhering surface (front surface) of a dicing tape 91. The outer peripheral portion of the dicing tape 91 is adhered to an annular frame 92 shown in FIGS. 1 and 2. Thereby, the substrate 90 is supported by the annular frame 92 via the dicing tape 91 and becomes a work set 9 that can be handled using the annular frame 92. The center of the annular frame 92 and the center of the substrate 90 are in a substantially coincident state.

[0019] Note that the substrate 90 to be processed may not be a work set 9 and may be in the state of a single substrate. Further, for example, on the planned division line 904 of the substrate 90, a TEG (Test Element Group) composed of a metal such as aluminum or copper and combining transistors, resistors, etc. may be formed at a predetermined interval. And the TEG is divided through a wiring layer (not shown) made of metal or the like and is electrically connected to the chip 909 provided with a device. Note that the metal formed on the planned division line 904 of the substrate 90 may be wiring other than the above example, and the substrate 90 may be a package substrate in which a device is laminated on the surface of a metal substrate other than a QFN substrate and resin-sealed, or a package substrate in which a metal film is coated as a heat sink on the surface of a substrate on which a planned division line is formed.

[0020] (1-1) Embodiment 1 of the processing groove formation step The cutting device 1 shown in FIG. 2 is a device capable of performing cutting processing on the substrate 90, and includes at least a holding means 15 for holding the substrate 90 and a cutting means 11 for cutting the substrate 90 with a rotatable cutting blade 112. In FIG. 2, the structure of the work set 9 is shown with a partial simplification.

[0021] The holding means 15 includes, for example, a flat holding surface 150 for holding the substrate 90, is rotatable about a rotation axis in the vertical direction (Z-axis direction), and is reciprocally movable in the X-axis direction (front-back direction in the paper plane) by a cutting feed means (not shown). The holding means 15 may be a porous chuck in which the holding surface 150 is made of a porous material, or a jig chuck provided with a blade relief groove on the holding surface 150. Further, when the substrate 90 is a work set 9 as in the present embodiment, around the holding means 15 shown in FIG. 2, fixing clamps 153 capable of sandwiching and fixing the annular frame 92 are evenly arranged, for example, at four equal intervals in the circumferential direction.

[0022] The cutting means 11 is capable of indexing feed in the Y-axis direction and cutting feed in the Z-axis direction (vertical direction). For example, it includes at least a cutting blade 112 that cuts into the substrate 90 while rotating, a rotatable spindle 113 that supports the cutting blade 112 mounted at the tip, and a motor (not shown). The cutting blade 112 may be an annular washer blade or a hub blade.

[0023] For example, in the vicinity of the cutting means 11, there is disposed an alignment means (not shown) that detects the planned division line 904 (see FIG. 1) of the substrate 90 held by the holding means 15. The alignment means can detect the position of the planned division line 904 on the surface 901 by image processing such as pattern matching based on the captured image of the surface 901 of the substrate 90.

[0024] In the processing groove formation step of performing blade dicing, first, the substrate 90 that is the work set 9 is placed on the holding surface 150 of the holding means 15, and the suction force generated by a suction source (not shown) is transmitted to the holding surface 150, and the substrate 90 is suction-held on the holding surface 150. The center of the substrate 90 and the center of the holding surface 150 are substantially coincident. Also, the annular frame 92 of the work set 9 is clamped and fixed by the fixed clamp 153.

[0025] For example, the holding means 15 that holds the substrate 90 rotates so that the longitudinal direction of the substrate 90 becomes the X-axis direction. Then, the holding means 15 that holds the substrate 90 is sent in the -X direction (back side of the paper), and the alignment means (not shown) detects the coordinate position in the Y-axis direction of the target planned division line 904 extending in the X-axis direction where the cutting blade 112 is to be cut in.

[0026] Next, alignment in the Y-axis direction is performed between the target division planned line 904 and the cutting blade 112, and the cutting blade 112 rotates at high speed in the counterclockwise direction as viewed from the +Y direction side, for example. Further, the cutting means 11 is fed in the cutting direction toward the -Z direction, and the lowermost end of the cutting blade 112 is positioned at a height where it fully cuts the substrate 90 and slightly cuts into the dicing tape 91. Note that the substrate 90 may be half-cut.

[0027] The substrate 90 shown in FIG. 2 is further fed out in the -X direction (the back side of the paper) at a predetermined cutting feed rate, so that the cutting blade 112 cuts into the substrate 90 along the division planned line 904, and cuts the substrate 90 while forming the processing groove 95 shown in FIG. 2. Since the metal 905 such as an electrode pad is disposed on the division planned line 904 shown in FIG. 1, the metal 905 becomes, for example, a whisker-like burr 96 shown in FIG. 2 due to its ductility, and is formed around the processing groove 95, that is, on the inner surface of the processing groove 95 and the upper end portion of the processing groove 95.

[0028] When the work set 9 is sent to a predetermined position on the -X direction side where the cutting blade 112 shown in FIG. 2 finishes cutting one division planned line 904, the cutting feed of the substrate 90 is stopped once, the cutting blade 112 is separated from the substrate 90, and then the substrate 90 is moved in the +X direction to return to the origin position. Then, by sequentially performing the same cutting while indexing and feeding the cutting blade 112 in the -Y direction by the interval between adjacent division planned lines 904, the substrate 90 is cut along all the division planned lines 904 in the X-axis direction.

[0029] Furthermore, the holding means 15 is rotated by 90 degrees and the same cutting is performed, so that all the division planned lines 904 are cut vertically and horizontally, and the substrate 90 is divided into chips 909 each including a device.

[0030] (1-2) Embodiment 2 of the processing groove formation step Instead of forming the processing groove 95 in the substrate 90 by the above-mentioned cutting, for example, the processing groove forming step may be carried out using the laser processing apparatus 2 shown in FIG. 3. The laser processing apparatus 2 includes at least a chuck table 20 that sucks and holds the substrate 90, and a laser beam irradiation means 22 that can irradiate the substrate 90 held on the chuck table 20 with a laser beam having, for example, an absorbent wavelength.

[0031] The chuck table 20 having a flat holding surface 200 communicating with a suction source (not shown) is rotatable and can reciprocate in the X-axis direction, which is the processing feed direction, and the Y-axis direction, which is the indexing feed direction, by a moving means (not shown).

[0032] The laser beam irradiation means 22 can accurately focus and irradiate the laser beam emitted from the laser beam oscillator 229 onto the target location of the substrate 90 held on the chuck table 20 by causing the laser beam to enter a condenser lens (not shown) inside the condenser 221 through the transmission optical system. The height position of the focus point of the laser beam can be adjusted in the Z-axis direction by a focus point position adjusting means (not shown).

[0033] In the laser processing apparatus 2, the substrate 90 is sucked and held on the holding surface 200 of the chuck table 20 with the surface 901 facing upward. Also, the annular frame 92 is clamped and fixed by a fixed clamp 204 disposed on the chuck table 20. Next, the position of the division planned line 904 serving as a reference for irradiating the laser beam is detected by an alignment means (not shown). Then, the chuck table 20 is indexed and fed in the Y-axis direction, and alignment in the Y-axis direction is performed between the division planned line 904 for irradiating the laser beam and the condenser 221.

[0034] Furthermore, the height position of the focus point of the laser beam condensed by a condenser lens (not shown) is adjusted, for example, to match the height position of the surface 901 of the substrate 90. Then, the laser beam oscillator 229 oscillates a laser beam having an absorbent wavelength for the substrate 90, and the laser beam is focused and irradiated onto the division planned line 904.

[0035] Also, the substrate 90 is fed in the -X direction (the back side of the paper surface), which is the forward direction, at a predetermined machining feed rate, and the laser beam irradiates the surface 901 of the substrate 90 along the planned division line 904. The substrate 90 is ablated from the surface 901 toward the back surface 907, and a machining groove 97 for cutting the substrate 90, for example, is formed along the planned division line 904. Note that the machining groove 97 may be a half-cut groove. At the same time, since a metal 905 such as an electrode pad is disposed on the planned division line 904 shown in FIG. 1, burrs 98 formed by melting the metal 905 are formed around the machining groove 97, that is, on the inner surface of the machining groove 97 and the upper end portion of the machining groove 97.

[0036] When the substrate 90 advances in the -X direction to a predetermined position where the irradiation of the laser beam along the planned division line 904 is completed, the irradiation of the laser beam is stopped. Further, the chuck table 20 is indexed and fed in the +Y direction by a predetermined distance, and the position directly below the condensing point of the condenser 221 is positioned on the next target planned division line 904. Then, the substrate 90 is fed for machining in the +X direction (the front side of the paper surface), which is the return direction. Similar to the laser beam irradiation in the forward direction, the substrate 90 is ablated along the planned division line 904, and the machining groove 97 is formed along the planned division line 904. Then, by sequentially performing similar laser processing while indexing and feeding the chuck table 20 in the -Y direction by the interval between adjacent planned division lines 904, the substrate 90 is cut along all the planned division lines 904 extending in the X-axis direction. Note that the laser irradiation for one planned division line 904 may be performed in two or more passes.

[0037] Furthermore, the chuck table 20 is rotated by 90 degrees and similar laser processing is performed, so that all the planned division lines 904 are cut both vertically and horizontally, and the substrate 90 is divided into chips 909 each including a device.

[0038] (2) Burr removal step After the machining groove forming step of Embodiment 1 or the machining groove forming step of Embodiment 2 is carried out, the workpiece set 9 is conveyed to the water tank 5 shown in FIG. 4. For example, the water tank 5 in which the entire substrate 90 supported by the annular frame 92 can be immersed is composed of a side wall 51 and a bottom plate 50 integrally connected to the lower part of the side wall 51, and the etching solution 500 is stored therein.

[0039] A mounting table 52 is disposed on the bottom plate 50. The mounting table 52 has a mounting surface 521 parallel to the XY plane. The workpiece set 9 is placed on the mounting surface 521. The etching solution 500 is supplied to the water tank 5 from an etching solution supply source (not shown). The water tank 5 has a drain port 511 for draining the etching solution 500, for example, on the side wall 51. The drain port 511 is located at a position higher than the mounting surface 521 of the mounting table 52 and higher than the upper surface of the workpiece set 9 placed on the mounting surface 521. Thereby, the workpiece set 9 placed on the mounting surface 521 is entirely immersed in the etching solution 500 stored in the water tank 5. A new etching solution 500 is supplied to the water tank 5 from an etching solution supply source (not shown), and the old etching solution 500 is sequentially drained from the drain port 511.

[0040] On the lower side (-Z direction side) surface of the mounting surface 521, for example, an ultrasonic oscillation unit 53 formed by arranging a plurality of piezoelectric elements in a disc shape is disposed. A terminal (not shown) is connected to the ultrasonic oscillation unit 53, and a voltage application unit 55 for applying an alternating voltage is connected via this terminal and wiring. Note that the shape and arrangement location of the ultrasonic oscillation unit 53 are not limited to this example. The ultrasonic waves generated by the ultrasonic oscillation unit 53 vibrate the mounting surface 521 and act on the workpiece set 9 placed on the mounting surface 521 from below. Since it is not preferable that the workpiece set 9 directly contacts the ultrasonic oscillation unit 53 in the water tank 5, the mounting surface 521 is provided in between.

[0041] The etching solution 500 contains at least an oxidizing agent, and in this embodiment, further contains an organic acid and a corrosion inhibitor.

[0042] As the organic acid, for example, a compound having at least one carboxyl group and at least one amino group in the molecule can be used. In this case, it is preferable that at least one of the amino groups is a secondary or tertiary amino group. Further, the compound used as the organic acid may have a substituent.

[0043] Examples of the amino acid that can be used as the organic acid 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-alan ine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine, L-lanthionine, L-cystathionine, L-cystine, L-cysteic 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, and antipain, etc. Among them, glycine, L-alanine, L-proline, L-histidine, L-lysine, and dihydroxyethylglycine are preferable.

[0044] In addition, examples of aminopolyacids that can be used as organic acids include iminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, hydroxyethyliminodiacetic acid, nitrilotris(methylenephosphonic acid), ethylenediamine-N,N,N’,N’-tetramethylenesulfonic acid, 1,2-diaminopropanetetraacetic acid, glycol ether diamine tetraacetic acid, trans-cyclohexanediaminetetraacetic acid, ethylenediamine orthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), β-alanine diacetic acid, N-(2-carboxylate ethyl)-L-aspartic acid, N,N’-bis(2-hydroxybenzyl)ethylenediamine-N,N’-diacetic acid, and the like.

[0045] Furthermore, examples of carboxylic acids that can be used as organic acids include saturated carboxylic acids such as formic acid, glycolic acid, propionic acid, acetic acid, butyric acid, valeric acid, hexanoic 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, glutaric acid; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, mesaconic acid, citraconic acid, aconitic acid; benzoic acids, toluic acids, phthalic acids, naphthoic acids, pyromellitic acid, naphthalic acid, and other cyclic unsaturated carboxylic acids.

[0046] As the oxidizing agent, for example, hydrogen peroxide, peroxides, nitrates, iodates, periodates, hypochlorites, chlorites, chlorates, perchlorates, persulfates, dichromates, permanganates, cerium salts, vanadates, ozone water, silver(II) salts, iron(III) salts, and their organic complex salts can be used.

[0047] In addition, as the anticorrosive agent, for example, it is preferable to use a heteroaromatic ring compound having three or more nitrogen atoms in the molecule and having a condensed ring structure, or a heteroaromatic ring compound having four or more nitrogen atoms in the molecule. Further, the aromatic ring compound preferably contains a carboxyl group, a sulfo group, a hydroxy group, or an alkoxy group. Specifically, a tetrazole derivative, a 1,2,3-triazole derivative, and a 1,2,4-triazole derivative are preferable.

[0048] Examples of the tetrazole derivative that can be used as the anticorrosive agent include those having no substituent on the nitrogen atom forming the tetrazole ring and having a substituent selected from the group consisting of a sulfo group, an amino group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group, or an alkyl group substituted with at least one substituent selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group introduced at the 5-position of tetrazole.

[0049] Examples of the 1,2,3-triazole derivative that can be used as the anticorrosive agent include those having no substituent on the nitrogen atom forming the 1,2,3-triazole ring and having a substituent selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group, or an alkyl group or an aryl group substituted with at least one substituent selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group introduced at the 4-position and / or 5-position of 1,2,3-triazole.

[0050] In addition, examples of 1,2,4-triazole derivatives that can be used as corrosion inhibitors include those having no substituent on the nitrogen atom forming the 1,2,4-triazole ring, and having a substituent selected from the group consisting of a sulfo group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group at the 2-position and / or 5-position of 1,2,4-triazole, or an alkyl group or an aryl group substituted with at least one substituent selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carboxamide group, a sulfamoyl group, and a sulfonamide group.

[0051] In the burr removal step of the present embodiment, for example, as shown in FIG. 4, the work set 9 is immersed in the etching solution 500 in the water tank 5 with the substrate 90 facing upward, and the work set 9 is placed on the placement surface 521 of the placement table 52. Then, a predetermined voltage is applied from the voltage application unit 55 to the ultrasonic oscillation unit 53, and the ultrasonic oscillation unit 53 mainly oscillates mechanically in the vertical direction to oscillate ultrasonic waves of a predetermined frequency. Then, the oscillated ultrasonic waves are propagated to the substrate 90 divided into chips 909 through the etching solution 500.

[0052] The burr 96 (or burr 98 shown in FIG. 3) made of metal formed around the processing groove 95 (or processing groove 97 shown in FIG. 3) of the substrate 90 is modified (oxidized) by the oxidizing agent contained in the etching solution 500, and the ductility of the metal is reduced. That is, it becomes brittle with respect to ultrasonic vibration. In the present embodiment, the etching solution 500 containing an organic acid further etches the burr 96 to make it thinner in parallel with the embrittlement. As a result, the burr 96 (burr 98) is removed from the chip 909 by the ultrasonic vibration transmitted from the etching solution 500.

[0053] In the burr removal step, the etching rate of the burr 96 is controlled, for example, by the composition ratio of the etching solution 500 containing an oxidizing agent, an organic acid, and a corrosion inhibitor. That is, the etching solution 500 may etch and damage metal parts and metal wiring that are the product parts of the device chip 909, but by controlling the composition ratio of the etching solution 500 containing an oxidizing agent, an organic acid, and an anticorrosive, and by controlling the time for which the substrate 90 is immersed in the etching solution 500, it is possible to prevent damage to the device chip 909 and efficiently remove the burrs 96 (burrs 98) from the chip 909. This is because the burrs 96 made of metal are mostly formed to protrude thin and long from the chip 909 toward the tip, so that the ductility is reduced and weakened by the oxidizing agent contained in the etching solution 500 more quickly than the product part of the chip 909, and further, the thin burrs 96 (burrs 98) are easily vibrated and broken by the application of ultrasonic vibration, so that it is possible to efficiently complete the removal of the burrs 96 (burrs 98) before the product part of the device chip 909 is damaged. Also, for example, since a device protection film such as an oxide film is generally formed on the surface of the device chip 909 in advance, the surface is less susceptible to damage from the etching solution 500 compared to the burr 96 (burr 98) portion.

[0054] For example, when the groove forming step of the above embodiment 1 or the groove forming step of embodiment 2 is carried out by adhesively fixing substrate 90 to a highly rigid substrate (carrier substrate) made of glass, silicon, or the like, in the burr removal step, substrate 90 divided into chips 909 together with the carrier substrate may be immersed in water tank 5.

[0055] Furthermore, in the processed groove forming step of the above-mentioned embodiment 1 or the processed groove forming step of embodiment 2, when half-cut grooves are formed without completely cutting the substrate 90, the undivided substrate 90 may be immersed in the water tank 5. Alternatively, for example, a plurality of chips 909 obtained by dividing the QFN substrate 90 may be released from the tape support and immersed in the water tank 5 as they are.

[0056] The ultrasonic oscillation unit 53 disposed in the water tank 5 is not limited to the disk-shaped one shown in FIG. 4. For example, as an ultrasonic horn that expands and contracts in the Z-axis direction, it is disposed so as to be immersed above the water tank 5, and while moving vertically and horizontally along the processing groove 95 (processing groove 97) of the substrate 90 placed on the mounting table 52 of the ultrasonic horn, the ultrasonic vibration is propagated to the etching solution 500, and the metal burrs 96 (burrs 98) generated around the processing groove 95 (processing groove 97) are modified by the oxidant contained in the etching solution 500 to suppress ductility and make them brittle, and at the same time, they may be removed by ultrasonic vibration. The ultrasonic vibration propagated to the etching solution 500 travels in the -Z direction, reaches the bottom plate 50 of the water tank 5, and then is reflected by the bottom plate 50 and returns to the liquid surface side. As a result, the ultrasonic wave (incident wave) heading toward the bottom plate 50 and the ultrasonic wave (reflected wave) reflected from the bottom plate 50 and returning to the liquid surface side overlap, resulting in a deep and a weak depth of sound pressure in the etching solution 500. And depending on the frequency of the ultrasonic wave, the depth with the highest sound pressure in the etching solution 500 exists at regular intervals in the Z-axis direction from the liquid surface. Therefore, measure the depth at which the sound pressure becomes the largest in the Z-axis direction in the etching solution 500 from the liquid surface with the liquid surface as the 0 position. Then, the height position of the substrate 90 placed on the mounting table 52 may be adjusted to the depth at which the sound pressure is the highest in the Z-axis direction in the etching solution 500, and the above ultrasonic vibration may be applied.

[0057] In addition, for example, an ultrasonic oscillation unit 53 may be disposed on the upper surface of the bottom plate 50, and a frame mounting table for mounting the annular frame 92 of the work set 9 may be evenly disposed at a predetermined interval in the circumferential direction in a region outside the region of the upper surface of the bottom plate 50 where the ultrasonic oscillation unit 53 is disposed. Then, the work set 9 is immersed in the etching solution 500 of the water tank 5 in a direction in which the ultrasonic oscillation unit 53 and the surface 901 of the substrate 90 face each other, and the annular frame 92 is placed on the upper surface of the frame mounting table. Then, a voltage is applied from the voltage application unit 55 to the ultrasonic oscillation unit 53, and ultrasonic vibration is applied from the ultrasonic oscillation unit 53 to the etching solution 500. In this case, for example, the burrs 96 (burrs 98) of the metal can be modified by the oxidizing agent contained in the etching solution 500 to suppress the ductility and make them brittle, so that they can be removed by ultrasonic vibration. At the same time, the bubbles (cavitation bubbles) generated in the etching solution 500 by the ultrasonic vibration rise in the processing grooves 95 (processing grooves 97) of the substrate 90 and hit the burrs 96 (burrs 98), and the shock wave when they break can remove the burrs 96 (burrs 98) well.

[0058] Also, the contact of the etching solution with the substrate 90 in the burr removal step is not limited to the form of immersing the substrate 90 in the water tank 5 storing the etching solution 500. For example, after placing the workpiece set 9 on the mounting table 52 of the water tank 5, the etching solution 500 may be sprayed vertically and horizontally along the processing grooves 95 (processing grooves 97) of the substrate 90 from the ultrasonic vibration nozzle disposed above the water tank 5. In this case, for example, the amount of the etching solution 500 used can be reduced. Also, the burrs 96 (burrs 98) of the metal are modified by the oxidizing agent contained in the etching solution 500 to suppress the ductility and make them brittle, and the burrs 96 can also be removed from the chip 909 by the impact when the sprayed etching solution 500 collides with the burrs 96 while ultrasonic vibration is applied.

[0059] As described above, the substrate processing method according to the present invention for processing the substrate 90 in which the metal 905 is formed on the planned division line 904 along the planned division line 904 includes a processing groove forming step of forming, for example, a processing groove 95 by dicing in the substrate 90 along the planned division line 904, and after the implementation of the processing groove forming step, bringing into contact the etching solution 500 containing at least an oxidizing agent and applied with ultrasonic vibration, and modifying the burrs 96 of the metal 905 generated around the formed processing groove 95 by the oxidizing agent contained in the etching solution 500 to suppress the ductility and make them brittle, and removing them by ultrasonic vibration. By providing these steps, the burrs 96 can be removed well, and it is not necessary for the operator to inspect each processing groove 95 for the presence or absence of burrs 96, so that the working efficiency of burr removal can be improved.

[0060] Also, by adding an etching solution 500 used in the burr removal step to an oxidizing agent to make it contain an organic acid, it becomes possible to increase the etching effect on the burrs 96.

[0061] Further, by adding an etching solution 500 used in the burr removal step to an oxidizing agent and further making it contain a corrosion inhibitor, it becomes possible to delay unnecessary etching on the device surface that becomes the product part of the chip 909.

[0062] In the burr removal step, the substrate 90 with the processing grooves 95 formed thereon, or a plurality of chips 909 fragmented by the processing grooves 95, are immersed in a water tank 5 having an ultrasonic oscillator 53 that stores the etching solution 500 and applies ultrasonic vibration, whereby the burrs 96 can be removed well in a short time.

[0063] It goes without saying that the substrate processing method according to the present invention is not limited to the above embodiment and may be implemented in various different forms within the scope of its technical idea. Also, regarding the configuration of each device used when implementing the processing method, it can be appropriately changed within the range where the effects of the present invention can be exhibited.

Explanation of Reference Numerals

[0064] 9: Workset 90: Substrate 900: Frame plate 901: Surface of the substrate 902: Device region 903: End material part 904: Division planned line 905: Metal 909: Chip 907: Back surface of the substrate 91: Dicing tape 92: Annular frame 95: Processing groove 96: Burr 97: Processing groove 98: Burr 1: Cutting device 11: Cutting means 113: Spindle 112: Cutting blade 15: Holding means 150: Holding surface 153: Fixed clamp 2: Laser processing device 20: Chuck table 200: Holding surface 22: Laser beam irradiation means 229: Laser beam oscillator 221: Condenser 5: Water tank 500: Etching solution 50: Bottom plate 51: Side wall 511: Drain 52: Placement table 521: Placement surface 53: Ultrasonic oscillator 55: Voltage application unit

Claims

Claim 1 A method for processing a substrate having a metal formed on a planned dividing line along the planned dividing line, comprising: a processing groove forming step of forming a processing groove in the substrate from the surface side of the substrate along the planned dividing line; after the implementation of the processing groove forming step, bringing an etching solution containing at least an oxidizing agent and subjected to ultrasonic vibration into contact with the substrate, and modifying the burrs of the metal generated around the formed processing groove with the oxidizing agent contained in the etching solution to suppress ductility and make them brittle, and removing them by the ultrasonic vibration, In the burr removing step, an ultrasonic oscillator for applying the ultrasonic vibration is disposed on the upper surface of the bottom plate of the water tank in which the etching solution is stored; immersing the substrate in the etching solution in a direction in which the ultrasonic oscillator and the surface of the substrate face each other; A method for processing a substrate. Claim 2 The method for processing a substrate according to claim 1, wherein the etching solution further contains an organic acid. Claim 3 The method for processing a substrate according to claim 1 or claim 2, wherein the etching solution further contains a corrosion inhibitor. Claim 4 The etching solution further contains at least one of an organic acid or a corrosion inhibitor, In the burr removing step, the etching rate of the burrs is controlled by the composition ratio of the etching solution containing the oxidizing agent and at least one of the organic acid or the corrosion inhibitor. The method for processing a substrate according to claim 1.

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