SUBSTANT PROCESSING METHOD

Abstract

Substrate processing method for processing a substrate (90) along a designated parting line (904) which has a metal (905) formed on the designated parting line (904), wherein the substrate processing method comprises: a machining groove formation step for forming a machined groove (95) in the substrate (90) along the intended parting line (904); and After the machining groove formation step has been carried out, a deburring step is performed in which an etchant containing at least one oxidizing agent and to which an ultrasonic vibration is applied is brought into contact with the substrate (90), suppressing the ductility of a metallic burr (96) that has been produced on an edge of the formed machining groove (95) and increasing the brittleness of the burr (96) by modifying the burr (96) by the oxidizing agent contained in the etchant, and removing the burr (96) by the ultrasonic vibration.

Description

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0001] The present invention relates to a substrate processing method for processing a substrate having a metal formed at predetermined parting lines, along the predetermined parting lines. DESCRIPTION OF THE RELATED PRIOR ART

[0002] In a case where machined grooves are formed in a substrate including metal parts, a metal film, metal-containing wiring, or the like, burrs are generated on the metal parts, causing problems such as a short circuit between chip terminals due to the generated burrs and the occurrence of a connection failure due to the burrs falling onto connection points during workpiece handling. Accordingly, a device has been proposed that jets high-pressure water from a nozzle onto the burrs, thereby removing the burrs (see, for example, Japanese Patent Application Laid-Open No. 2007-125667 A).

[0003] German Patent Application DE 10 2019 212 183 A1 discloses a package substrate processing method for processing a package substrate having a parting line, wherein an electrode is formed on the parting line. The method includes a cutting step of cutting the package substrate along the parting line using a cutting blade, and a burr removal step of removing burrs generated by the electrode in the cutting step by spraying a fluid to the package substrate along the parting line after performing the cutting step. The cutting step includes a step of supplying a cutting fluid containing an organic acid and an oxidizing agent to a cutting area where the package substrate is to be cut by the cutting blades.

[0004] US Pat. No. 6,162,366 A proposes an etching method comprising the steps of preparing an etchant containing ferric chloride and an anticorrosive agent for Cu, and etching a multilayer metal structure containing a Cu layer and a Ni layer with this etchant. The etching method aims to ensure that the etching rates of the respective layers are substantially equal, thereby suppressing the occurrence of burrs in the Ni layers. SUMMARY OF THE INVENTION

[0005] However, even if the technology disclosed in JP 2007 - 125 667 A is applied, it is difficult to properly remove the burrs on the edges of the machined grooves, and a human performs the inspection work on the machined grooves and deburring after the formation of the machined grooves, which causes inefficiency.

[0006] Accordingly, it is an object of the present invention to provide a substrate processing method that can properly remove burrs from a fully cut or half-cut substrate and improve the work efficiency of deburring in the case of processing the substrate having a metal formed at intended parting lines along the intended parting lines.

[0007] In accordance with one aspect of the present invention, there is provided a substrate processing method for processing a substrate having a metal formed on a predetermined parting line along the predetermined parting line, the substrate processing method comprising a processing groove forming step of forming a processed groove in the substrate along the predetermined parting line and, after the processing groove forming step is performed, a deburring step of bringing an etchant containing at least one oxidizer and to which ultrasonic vibration is applied into contact with the substrate, suppressing the ductility of a metallic burr generated at an edge of the formed processed groove, increasing the fragility of the burr by modifying the burr by the oxidizer contained in the etchant, and removing the burr by the ultrasonic vibration.

[0008] Preferably, the etchant further comprises an organic acid. Preferably, the etchant further comprises a corrosion inhibitor.

[0009] Preferably, the deburring step immerses the substrate in which the machined groove is formed, or a plurality of chips divided into individual pieces by the machined grooves, in a tank containing the etchant and including an ultrasonic oscillating unit that applies the ultrasonic vibration.

[0010] Preferably, the rate at which the burrs are etched is controlled by a composition ratio of the etchant including the oxidizer and at least one of the organic acid and the corrosion inhibitor.

[0011] According to the present invention, it is possible to remove the burrs excellently and improve the work efficiency in deburring.

[0012] If the etchant used in deburring also contains an organic acid in addition to the oxidizing agent, the effect of etching for deburring can be enhanced.

[0013] If the etchant used in the deburring step contains a corrosion inhibitor in addition to the oxidizer, unnecessary etching of the surfaces of the component chips can be delayed.

[0014] When the deburring step immerses the substrate in which the machined grooves are formed or the multiple chips divided into individual pieces by the machined grooves into the tank containing the etchant and including the ultrasonic oscillating unit that applies the ultrasonic vibrations, the burrs can be excellently removed in a short time.

[0015] The above and other objects, features and advantages of the present invention and the mode for carrying them into effect will become more apparent and the invention itself will be best understood by studying the following description and the appended claims with reference to the attached drawings which show some preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view illustrating an example of a substrate to be processed; Fig. 2 is a side view of assistance in explaining an example of a machining groove forming step in which machined grooves are formed in the substrate along intended parting lines by blade cutting; Fig. 3 is a side view of assistance in explaining another example of the machining groove forming step in which the machined grooves are formed in the substrate along the intended parting lines by laser dicing; and Fig. 4 is a sectional view of assistance in explaining an example of a deburring step using a tank containing an etchant. DETAILED EXPLANATION OF THE PREFERRED EMBODIMENTS

[0016] One in Fig. The substrate 90 illustrated in Figure 1, which is to be subjected to subdivision processing, is, for example, a quad flat non-leaded package substrate (QFN substrate). The substrate 90 has a frame plate 900 with a rectangular outer shape. A plurality of component regions 902 (in the region shown in Fig. 1, three component regions 902), which become individual component chips 909 with components by division, are arranged in a longitudinal direction of the substrate 90 on an upper surface 901 of the substrate 90 shown in Fig. 1. The edge of each of the components 902 is surrounded by end material portions 903, which are to be formed into small pieces and disposed of.

[0017] The component regions 902 are delimited by a plurality of provided dividing lines 904 extending perpendicular to each other. Metals 905 are arranged on the provided dividing lines 904, forming a plurality of electrode pads or the like connected to the respective components (not shown). The metals 905 are insulated from each other by a molding resin (not shown) on the frame plate 900. When the centers of the plurality of metals 905 are cut along the provided dividing lines 904, the substrate 90 is divided into the chips 909, which include the molding resin that seals the components (not shown) and the plurality of cut metals 905. Incidentally, for example, an oxide layer made of SiO2 or the like or a resin layer with a thickness in the μm range can be formed on the component region 902 as a component protection surface material.

[0018] As in Fig. 2, for example, a lower surface 907 (see Fig. 2) of the substrate 90 is attached to the attachment surface (upper surface) of a release tape 91. An outer peripheral portion of the release tape 91 is attached to a Fig. 1 and Fig. 2. Thus, the substrate 90 is supported by the annular frame 92 via the separating tape 91, forming a frame unit 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 substantially coincident.

[0019] Incidentally, the substrate 90 to be processed may be in a state including only the substrate and not the frame unit 9. Furthermore, for example, test element groups (TEGs) made of metal such as aluminum or copper and formed by a combination of a transistor, a resistor, and the like may be formed at predetermined intervals on the provided dividing lines 904 of the substrate 90. The TEGs are electrically connected to the divided chips 909 and sandwich the components via a wiring layer (not illustrated) made of metal or the like. Incidentally, the metals formed on the provided dividing lines 904 of the substrate 90 may be wiring different from the above-described example.The substrate 90 may be a package substrate in which components are layered on the upper surface of a metal substrate other than a QFN substrate and sealed with resin, or the substrate 90 may be a package substrate in which a metal film as a heat sink covers the upper surface of a substrate on which predetermined parting lines are formed. (1-1) First embodiment of the machining groove forming step

[0020] One in Fig. The cutting device 1 illustrated in Figure 2 is a device that can perform a cutting operation on the substrate 90. The cutting device 1 includes at least a holding unit 15 that holds the substrate 90 and a cutting unit 11 that cuts the substrate 90 by a rotatable cutting blade 112. In Fig. 2, the structure of frame unit 9 is partly illustrated in a simplified manner.

[0021] The holding unit 15 has, for example, a flat holding surface 150 that holds the substrate 90. The holding unit 15 is rotatable about a rotation axis in a vertical direction (Z-axis direction) and can be reciprocated in an X-axis direction (directions of a front and a back of a paper plane) by cutting feed means not shown. The holding unit 15 may be a porous chuck whose holding surface 150 is formed of a porous material, or may be a clamping device that has blade clearance grooves in the holding surface 150. In addition, on the periphery of the Fig. 2, for example, four fixing brackets 153, which can hold and fix the annular frame 92 in a case where the substrate 90 forms the frame unit 9 as in the present embodiment, are evenly arranged in a circumferential direction at equal intervals.

[0022] The cutting unit 11 can be tilted in the Y-axis direction and cut in the Z-axis direction (vertical direction). The cutting unit 11 includes, for example, at least the cutting blade 112 that cuts into the substrate 90 while rotating, a rotatable spindle 113 that supports the cutting blade 112 at its distal end, and a motor (not shown). The cutting blade 112 can be an annular disc blade or a hub blade.

[0023] An alignment means (not illustrated) for detecting a designated parting line 904 (see Fig. 1) of the substrate 90 held by the holding unit 15 is arranged, for example, in the vicinity of the cutting unit 11. The alignment means can detect the position of the intended cutting line 904 of the upper surface 901 through image processing, such as pattern matching, with respect to an imaged image of the upper surface 901 of the substrate 90.

[0024] In a machining groove forming step using blade cutting, first, the substrate 90 constituting the frame unit 9 is attached to the holding surface 150 of the holding unit 15, and suction force generated by an unillustrated suction source is transmitted to the holding surface 150, so that the substrate 90 is held on the holding surface 150 under suction. The center of the substrate 90 and the center of the holding surface 150 substantially coincide with each other. Furthermore, the annular frame 92 of the frame unit 9 is held and fixed by the fixing brackets 153.

[0025] The holding unit 15 holding the substrate 90 is rotated so that the longitudinal direction of the substrate 90 becomes, for example, the X-axis direction. Next, the holding unit 15 holding the substrate 90 is fed in an X-axis direction (back of the paper plane), and the unillustrated alignment means detects the coordinate position in the Y-axis direction of a designated target cutting line 904, which extends in the X-axis direction and into which the cutting blade 112 is to be brought for cutting.

[0026] Next, the intended target separation line 904 and the cutting blade 112 are aligned with each other in the Y-axis direction, and the cutting blade 112 is rotated at high speed, for example, counterclockwise from the +Y direction side. Further, the cutting unit 11 is fed in a -Z direction for cutting, and a lowermost end of the cutting blade 112 is positioned at a height position where the cutting blade 112 completely cuts the substrate 90 and slightly cuts the separation tape 91. Incidentally, the substrate 90 may also be half-cut.

[0027] If that in Fig. 2 is further fed in the -X direction (back of the paper plane) at a predetermined cutting feed rate, the cutting blade 112 cuts into the substrate 90 along the intended separation line 904 and cuts the substrate 90 to form a Fig. 2. The metal 905, such as an electrode pad, is deposited on the groove 95 shown in Fig. 1. Thus, due to the ductility of the metal 905, the metal 905 is formed, for example, into a Fig. 2, which is formed on the edge of the machined groove 95, that is, on the inner surface of the machined groove 95 and on upper end portions of the machined groove 95.

[0028] When the frame unit 9 is fed to a predetermined position on the -X direction side where the Fig. When the cutting blade 112 illustrated in FIG. 2 completes cutting the one designated dividing line 904, the cutting feed of the substrate 90 is temporarily stopped, the cutting blade 112 is separated from the substrate 90, and then the substrate 90 is moved in a +X direction and returned to an initial position. Then, similar cutting is successively performed while the cutting blade 112 is adjusted in a -Y direction at intervals between the adjacent designated dividing lines 904. The substrate 90 is thereby cut along all the designated dividing lines 904 in the X-axis direction.

[0029] Further, the holding unit 15 is rotated 90 degrees, and a similar cut is performed. Consequently, all the intended separation lines 904 are cut in the longitudinal and transverse directions, and the substrate 90 is divided into the chips 909 containing the components. (1-2) Second embodiment of the machining groove forming step

[0030] Instead of forming the machining grooves 95 in the substrate 90 by the cutting described above, the machining groove forming step may be performed, for example, by using a Fig. 3. The laser processing apparatus 2 includes at least one chuck table 20 that holds the substrate 90 under suction, and a laser beam irradiation unit 22 that can irradiate the substrate 90 held on the chuck table 20 with a laser beam of a wavelength that is absorbable, for example, by the substrate 90.

[0031] The clamping table 20, which is connected to a suction source not shown and has a flat holding surface 200, can be rotated and is movable back and forth in the X-axis direction as a machining feed direction and in the Y-axis direction as an adjustment feed direction by moving means not shown.

[0032] The laser beam irradiation unit 22 allows the laser beam emitted from a laser oscillator 229 to enter a condenser lens (not shown) in a condenser 221 via an optical transmission system. The laser beam irradiation unit 22 can thereby accurately condense the laser beam and apply it to a target position of the substrate 90 held by the chuck table 20. The height position of a focal point of the laser beam can be adjusted in the Z-axis direction by a focal point position adjustment means (not shown).

[0033] In the laser processing apparatus 2, the substrate 90 is held under suction on the holding surface 200 of the chuck table 20 in a state in which the upper surface 901 is directed upward. In addition, the ring frame 92 is held and fixed by the fixing clamps 204 arranged on the chuck table 20. Next, the position of a designated parting line 904 as a reference for applying the laser beam is detected by an alignment means (not shown).

[0034] Then, the chuck table 20 is adjusted in the Y-axis direction, and the intended parting line 904 to be irradiated with the laser beam and the condenser 221 are aligned with each other in the Y-axis direction.

[0035] Further, the height position of the focal point of the laser beam condensed by the unillustrated condenser lens is adjusted to, for example, the height position of the upper surface 901 of the substrate 90. Then, the laser oscillator 229 emits the laser beam with a wavelength absorbable by the substrate 90 and focuses and applies the laser beam to the intended dividing line 904.

[0036] In addition, the substrate 90 is fed in the -X direction (back of the paper plane) as the forward direction at a predetermined machining feed rate, the laser beam is applied along the intended cutting line 904 to the top side 901 of the substrate 90, and the substrate 90 is ablated from the top side 901 to the bottom side 907, so that a machined groove 97 is formed along the intended cutting line 904, which, for example, cuts the substrate 90. The machined groove 97 may be a half-cut groove. Since the metal 905, such as an electrode pad, is applied to the Fig. 1, the metal 905 is simultaneously formed as a molten burr 98 on the edge of the machined groove 97, that is, on the inner surface of the machined groove 97 and on the upper end portions of the machined groove 97.

[0037] The laser beam application is stopped when the substrate 90 is advanced in the -X direction to a predetermined position where the laser beam application along the designated dividing line 904 is to be terminated. Further, the chuck table 20 is tilted in a +Y direction by a predetermined amount, and the focal point of the condenser 221 is positioned on a next designated target dividing line 904. Then, the substrate 90 is fed in the +X direction (near the paper plane) as the return direction, and as in the forward laser beam application, the substrate 90 is ablated along the designated dividing line 904, so that a machined groove 97 is formed along the designated dividing line 904. Then, similar laser processing is sequentially performed while the chuck table 20 is tilted in the -Y direction at intervals of the adjacent designated dividing lines 904.The substrate 90 is thereby cut along all the designated dividing lines 904 extending in the X-axis direction. Furthermore, the laser irradiation of a designated dividing line 904 may be performed in two or more passes.

[0038] Further, the clamping table 20 is rotated 90 degrees, and similar laser processing is performed. Consequently, all designated separation lines 904 are cut in the longitudinal and transverse directions, and the substrate 90 is divided into chips 909 containing the components. (2) Deburring step

[0039] After the machining groove forming step of the first embodiment or the machining groove forming step of the second embodiment has been carried out, the frame unit 9 is turned into a Fig. 4. The tank 5, into which, for example, the entire substrate 90 supported by the annular frame 92 can be immersed, includes side walls 51 and a bottom plate 50 integrally connected to lower portions of the side walls 51. The tank 5 contains an etchant 500.

[0040] A receiving table 52 is arranged on the base plate 50. The receiving table 52 has a receiving surface 521 that runs parallel to an X-axis and Y-axis plane. The frame unit 9 is attached to the receiving surface 521. The tank 5 is supplied with the etchant 500 from an unillustrated etchant supply source. The tank 5 has, for example, in a side wall 51, a drain port 511 for draining the etchant 500. The drain port 511 is arranged at a position higher than the receiving surface 521 of the receiving table 52 and higher than the upper surface of the frame unit 9 attached to the receiving surface 521. The entire frame unit 9 attached to the receiving surface 521 is thus immersed in the etchant 500 contained in the tank 5. A new etchant 500 is supplied to tank 5 from the etchant supply source (not shown). The old etchant 500 is successively drained through drain port 511.

[0041] An ultrasonic oscillation unit 53, formed, for example, by arranging a plurality of piezoelectric elements in the shape of a disk, is arranged on the lower (-Z direction side) surface of the receiving surface 521. A terminal (not shown) is connected to the ultrasonic oscillation unit 53. A voltage application unit 55 that applies an alternating voltage is connected to the ultrasonic oscillation unit 53 via the terminal and wiring. Note that the shape, arrangement position, and the like of the ultrasonic oscillation unit 53 are not limited to those mentioned in this example. An ultrasonic wave generated by the ultrasonic oscillation unit 53 vibrates the receiving surface 521 and acts from a lower side on the frame unit 9 attached to the receiving surface 521. It is undesirable for the frame unit 9 to be in direct contact with the ultrasonic oscillation unit 53 in the tank 5.Therefore, the receiving surface 521 is arranged between the frame unit 9 and the ultrasonic oscillating unit 53.

[0042] The etchant 500 includes at least one oxidizing agent. In the present embodiment, the etchant 500 further includes an organic acid and a corrosion inhibitor.

[0043] For example, a compound that contains at least one carboxyl group and at least one amino group in one molecule can be used as the organic acid. In this case, the at least one amino group is preferably a secondary or tertiary amino group. Furthermore, the compound used as the organic acid may contain a substituent.

[0044] Amino acids that can be used as organic acids include glycine, dihydroxyethylglycine, glycylglycine, hydroxyethylglycine, N-methylglycine, β-alanine, L-alanine, L-2-aminobutyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-aloisoleucine, 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-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 Cl, ergothioneine, apamin, angiotensin I, angiotensin II, antipain and the like.In particular, glycine, L-alanine, L-proline, L-histidine, L-lysine and dihydroxyethylglycine are preferable.

[0045] In addition, aminopolyacids that can be used as the organic acid may include iminodiacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, hydroxyethyliminodiacetic acid, nitrilotrismethylenephosphonic acid, ethylenediamine-N,N,N',N'-tetramethylenesulfonic acid, 1, 2-diaminopropanetetraacetic acid, glycol ether diaminetetraacetic acid, transcyclohexanediaminetetraacetic acid, ethylenediamineorthohydroxyphenylacetic acid, ethylenediamine disuccinic acid (SS form), β-alaninediacetic acid, N-(2-carboxylateethyl)-L-aspartic acid, N,N'-bis-(2-hydroxybenzyl)-ethylenediamine-N,N'-acetic acid, and the like.

[0046] Further, carboxylic acids that can be used as the organic acid may include 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, and other saturated carboxylic acids, acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, mesaconic acid, citraconic acid, aconitic acid and other unsaturated carboxylic acids, benzoic acids, toluic acid, phthalic acids, naphthoic acids, pyromellitic acid, naphthalic acid and other cyclic unsaturated carboxylic acids, and the like.

[0047] Oxidizing agents that can be used include, for example, hydrogen peroxide, peroxides, nitrate, iodate, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, dichromate, permanganate, cerate, vanadate, ozone water, silver(II) salt, iron(III) salt, organic complex salts thereof and the like.

[0048] Furthermore, for use as a corrosion inhibitor, a heteroaromatic ring compound having three or more nitrogen atoms in one molecule and a condensed ring structure, or a heteroaromatic ring compound having four or more nitrogen atoms in one molecule, is preferably used. Furthermore, an aromatic ring compound preferably includes a carboxyl group, a sulfo group, a hydroxy group, or an alkoxy group. In particular, the aromatic ring compound is preferably a tetrazole derivative, a 1,2,3-triazole derivative, or a 1,2,4-triazole derivative.

[0049] Tetrazole derivatives that can be used as corrosion inhibitors include those that do not have a substituent on a nitrogen atom forming a tetrazole ring and are obtained by introducing a substituent selected from a group consisting of a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group, and a sulfonamide group into the 5-position of a tetrazole, or an alkyl group replaced by at least one substituent selected from a group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group, and a sulfonamide group.

[0050] In addition, 1,2,3-triazole derivatives that can be used as anticorrosive agents include those that do not have a substituent on a nitrogen atom forming a 1,2,3-triazole ring and are obtained by introducing a substituent selected from a group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group into the 4-position and / or 5-position of a 1,2,3-triazole, or an alkyl group or an aryl group replaced by at least one substituent selected from a group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group.

[0051] In addition, 1,2,4-triazole derivatives that can be used as anticorrosive agents include those that do not have a substituent on a nitrogen atom forming a 1,2,4-triazole ring and are obtained by introducing a substituent selected from a group consisting of a sulfo group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group into the 2-position and / or 5-position of a 1,2,4-triazole, or an alkyl group or an aryl group, which is replaced by at least one substituent selected from a group consisting of a hydroxy group, a carboxy group, a sulfo group, an amino group, a carbamoyl group, a carbonamide group, a sulfamoyl group and a sulfonamide group.

[0052] In the present embodiment, in a Fig. For example, in the deburring step illustrated in Figure 4, the frame unit 9 is immersed in the etchant 500 of the tank 5 so that the substrate 90 is oriented upward, and the frame unit 9 is mounted on the support surface 521 of the support table 52. Then, a predetermined voltage is applied from the voltage applying unit 55 to the ultrasonic oscillation unit 53, and the ultrasonic oscillation unit 53 oscillates an ultrasonic wave at a predetermined frequency by mechanically oscillating mainly in an up-down direction. Then, the oscillated ultrasonic wave is transmitted to the substrate 90 divided into chips 909 via the etchant 500.

[0053] The metal ridges 96 (or the ones in Fig. 3 illustrated burrs 98) which are located at the edge of the machining grooves 95 (or the Fig. 3) of the substrate 90 are modified (oxidized) by the oxidizing agent contained in the etchant 500, and the ductility of the metal is reduced. That is, the burrs 96 (or the burrs shown in Fig. 3) become brittle with respect to the ultrasonic vibration. In the present embodiment, the burrs 96 (or the burrs 98 shown in Fig. 3) are etched by the etchant 500 containing the organic acid to further thin in parallel with the increase in fragility. As a result, the ultrasonic vibration emanating from the etchant 500 removes the burrs 96 (burrs 98) from the chips 909.

[0054] Incidentally, in the deburring step, the rate at which the burrs 96 are etched is controlled by a composition ratio of the etchant 500, which includes, for example, the oxidizing agent, the organic acid, and the anticorrosive agent. That is, while there is a possibility that the etchant 500 may etch and damage metal parts and metal wiring as product parts that form the component chips 909, it is possible to prevent damage to the component chips 909 and efficiently remove the burrs 96 (burrs 98) from the chips 909 by controlling the composition ratio of the etchant 500, which includes the oxidizing agent, the organic acid, and the anticorrosive agent, and controlling a time period for which the substrate 90 is immersed in the etchant 500.

[0055] This is because most of the metal-formed fins 96 are formed in such a way that they protrude from the chips 909 and are elongated toward the ends thereof. A decrease in ductility and an increase in brittleness of the fins 96 by the oxidizer contained in the etchant 500 gradually progresses faster than in the product parts of the chips 909. Furthermore, the thin fins 96 (fins 98) are vibrated and made prone to breakage by the action of ultrasonic vibrations on the fins 96. In this way, the removal of the fins 96 (fins 98) can be efficiently completed at a stage before the product parts of the device chips 909 are damaged. Furthermore, a protective film such as an oxide film is generally formed on the upper surfaces of the device chips 909 in advance.The upper surfaces of the device chips 909 are therefore less susceptible to damage by the etchant 500 than the parts of the ridges 96 (ridges 98).

[0056] For example, in a case where the substrate 90 is bonded and fixed to a substrate (support substrate) having high rigidity made of glass, silicon, or the like, and the machining groove forming step in the foregoing first embodiment or the machining groove forming step in the second embodiment is performed, the substrate 90 divided into the chips 909 may be immersed in the tank 5 together with the support substrate during the deburring step.

[0057] Furthermore, in a case of forming half-cut grooves instead of completely cutting the substrate 90 during the machining groove forming step of the foregoing first embodiment or during the machining groove forming step of the second embodiment, only the undivided substrate 90 may be immersed in the tank 5. Alternatively, for example, the plurality of chips 909 obtained by dividing the QFN substrate 90 into individual pieces may be immersed as they are in the tank 5 with the support of the tape removed.

[0058] The ultrasonic oscillating unit 53 arranged in the tank 5 is not limited to the Fig.4. For example, the ultrasonic oscillation unit may be arranged as an ultrasonic horn that expands or contracts in the Z-axis direction, so that the ultrasonic horn is immersed in an upper part of the tank 5. Ultrasonic vibration may propagate to the etchant 500 while the ultrasonic horn is moved longitudinally and transversely along the machined grooves 95 (machined grooves 97) of the substrate 90 mounted on the support table 52. The metal burrs 96 (burrs 98) generated at the edges of the machined grooves 95 (machined grooves 97) may be modified by the oxidizing agent contained in the etchant 500 to inhibit the ductility of the burrs 96 (burrs 98) and increase the fragility of the burrs 96 (burrs 98), and the burrs 96 (burrs 98) may be removed by the ultrasonic vibration.

[0059] Incidentally, the ultrasonic vibration propagating in the etchant 500 propagates in the -Z direction, reaches the bottom plate 50 of the tank 5, is then reflected by the bottom plate 50, and returns to the liquid surface side. Consequently, an ultrasonic wave traveling toward the bottom plate 50 (incident wave) and an ultrasonic wave reflected by the bottom plate 50 and returning to the liquid surface side (reflected wave) are superimposed on each other, and a depth of strong sound pressure and a depth of weak sound pressure are generated in the etching solution 500. A depth of the highest sound pressure in the etching solution 500 is located at fixed distances in the Z-axis direction from the liquid surface in accordance with the frequency of the ultrasonic waves.Therefore, a depth at which the sound pressure in the Z-axis direction in the etchant 500 is highest is measured from the liquid surface when the liquid surface is set as the zero position. Then, the above-described ultrasonic vibration can be applied after adjusting the height position of the substrate 90 mounted on the support table 52 to the depth at which the sound pressure in the Z-axis direction in the etchant 500 becomes highest.

[0060] Incidentally, for example, the ultrasonic oscillation unit 53 may be disposed on the upper surface of the bottom plate 50, and frame mounting bases to which the annular frame 92 of the frame unit 9 is to be attached may be uniformly arranged at predetermined intervals in the circumferential direction in an area outside the area of ​​the upper surface of the bottom plate 50 where the ultrasonic oscillation unit 53 is disposed. Then, the frame unit 9 is immersed in the etchant 500 of the tank 5 in an orientation in which the ultrasonic oscillation unit 53 and the upper surface 901 of the substrate 90 face each other, and the annular frame 92 is attached to the upper surfaces of the frame mounting bases. A voltage is then applied to the ultrasonic oscillation unit 53 by the voltage applying unit 55. As a result, ultrasonic vibration is applied to the etchant 500 by the ultrasonic oscillation unit 53.

[0061] In this case, for example, the metal burrs 96 (burrs 98) can be modified by the oxidizing agent contained in the etchant 500 to suppress the ductility of the metal burrs 96 (burrs 98) and increase the brittleness of the metal burrs 96 (burrs 98), and the metal burrs 96 (burrs 98) can be removed by the ultrasonic vibration; at the same time, the burrs 96 (burrs 98) can be excellently removed by a shock wave generated when air bubbles (cavitation air bubbles) generated in the etchant 500 by the ultrasonic vibration rise in the machining grooves 95 (machining grooves 97) of the substrate 90, hit the burrs 96 (burrs 98), and collapse.

[0062] Furthermore, the contact of the etchant with the substrate 90 during the deburring step is not limited to the form in which the substrate 90 is immersed in the tank 5 containing the etchant 500. For example, after attaching the frame unit 9 to the support table 52 of the tank 5, the etchant 500 may be ejected from an ultrasonic vibration nozzle arranged above the tank 5 in the longitudinal and transverse directions along the machining grooves 95 (machining grooves 97) of the substrate 90. In this case, for example, the consumption of the etchant 500 can be reduced.In addition, it is possible to suppress the ductility of the burrs 96 (burrs 98) and increase the fragility of the burrs 96 (burrs 98) by modifying the burrs 96 (burrs 98) by the oxidizer contained in the etchant 500, and also to remove the burrs 96 from the chip 909 by an impact generated when the etchant 500, which is ejected while applying ultrasonic vibration thereto, impacts the burrs 96.

[0063] As described above, a substrate processing method according to the present invention includes processing the substrate 90 along the designated parting lines 904 having the metals 905 formed on the designated parting lines 904, the processing groove forming step of forming the processed grooves 95 by cutting, for example, into the substrate 90 along the designated parting lines 904, and, after the processing groove forming step is performed, the deburring step of bringing the etchant 500 containing at least the oxidizing agent and to which ultrasonic vibration is applied into contact with the substrate 90, which suppresses the ductility of the burrs 96 of the metals 905 and increases the fragility of the burrs 96 generated at the edges of the formed processing grooves 95 by modifying the burrs 96 with the oxidizing agent.contained in the etchant 500, and the burrs 96 are removed by ultrasonic vibration. This makes it possible to remove the burrs 96 excellently and improve the work efficiency of deburring, since a worker does not have to check the machining grooves 95 individually for the presence or absence of the burrs 96.

[0064] If the etchant 500 used for the deburring step contains an organic acid in addition to the oxidizing agent, the etching effect on the burrs 96 can be enhanced.

[0065] Further, if the etchant 500 used for the deburring step includes a corrosion inhibitor in addition to the oxidizing agent, unnecessary etching of the surfaces of the components as product parts of the chips 909 can be delayed.

[0066] When the deburring step immerses the substrate 90 in which the machining grooves 95 are formed, or the plurality of chips 909 divided into individual pieces by the machining grooves 95, into the tank 5 containing the etchant 500 and including the ultrasonic oscillation unit 53 that generates ultrasonic vibration, the burrs 96 can be excellently removed in a short time.

[0067] Needless to say, the machining method according to the present invention is not limited to the above embodiments and can be implemented in a variety of forms within the scope of the technical concept of the present invention. Furthermore, the configuration or the like of each device used in implementing the machining method can be modified accordingly within a range in which the effects of the present invention can be exerted.

Claims

[1] A substrate processing method for processing a substrate (90) along a designated parting line (904) having a metal (905) formed on the designated parting line (904), the substrate processing method comprising: a machining groove forming step for forming a machined groove (95) in the substrate (90) along the intended parting line (904); and after the machining groove forming step has been carried out, a deburring step in which an etchant containing at least one oxidizing agent and to which an ultrasonic vibration is applied is brought into contact with the substrate (90), wherein a ductility of a metallic burr (96) generated at an edge of the formed machining groove (95) is suppressed and a fragility of the burr (96) is increased by modifying the burr (96) by the oxidizing agent contained in the etchant, and the burr (96) is removed by the ultrasonic vibration. [2] The substrate processing method according to claim 1, wherein the etchant further includes an organic acid. [3] The substrate processing method according to claim 1, wherein the etchant further includes a corrosion inhibitor. [4] The substrate processing method according to claim 1, wherein the deburring step immerses the substrate in which the machined groove is formed or a plurality of chips divided into individual pieces by the machined grooves into a tank containing the etchant and including an ultrasonic oscillating unit that applies the ultrasonic vibration. [5] The substrate processing method according to claim 3, wherein a speed at which the burrs are etched in the deburring step is controlled by a composition ratio of the etchant including the oxidizing agent and at least one of the organic acid and the anticorrosive agent.

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