JP2011156612A - Diamond blade, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long-life diamond blade with which a narrow groove width can be machined with high accuracy while suppressing occurrence of chipping, and to provide a manufacturing method thereof. <P>SOLUTION: The diamond blade includes: a metal base having a circular shape or disk-like shape; and a diamond particle group grown at least on an outer peripheral part of that metal base. After the base having the circular shape or disk-like shape preferably made of molybdenum, tantalum, or an alloy containing molybdenum or tantalum is annealed to remove strain, at least the outer peripheral part of the annealed base is scratched with diamond powder and then diamond particles are grown on the outer peripheral part of the base which is scratched with the diamond powder. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a diamond blade and a manufacturing method thereof.

As a processing tool for cutting or cutting hard-to-machine materials (hard-working materials) such as hard materials, brittle materials, ductile materials, resin materials, etc., a base material such as ceramics was used, and diamond was provided at the cutting edge. A diamond blade is used.
As such a diamond blade, for example, diamond particles are bonded and fixed to the outer periphery of a ring-shaped base material (support) with a resin, electrodeposited and fixed with nickel or the like, diamond-like carbon ( DLC) and diamond particles embedded in DLC have been proposed (see, for example, Patent Documents 1 and 2).

  Further, it has been proposed that a sapphire substrate for manufacturing an LED is grooved by a laser and then ruptured along a portion where the thickness has been reduced by grooving to be separated into pieces (non-non-woven). Patent Document 1).

Japanese Patent Laid-Open No. 8-127023 JP 2006-305707 A

SEMICONDUCTOR International Japan edition November 2009 issue (http://www.sijapan.com/issue/2009/11/lo86kc000000lop6.html)

  When diamond particles are produced by pulverizing synthesized diamond, especially when compared in terms of hardness, for example, natural diamond is very low at Hv 4000 to 5000 compared to Vickers hardness Hv 10000. Such pulverized diamond particles are fixed to the outer periphery of an annular ceramic base material by resin or electrodeposition to produce a diamond blade, and used for cutting or cutting of a silicon carbide (SiC) substrate for a semiconductor wafer, for example. In this case, there are problems that the processing speed is slow, the diamond particles are likely to fall off, the blade life is short, chipping is likely to occur on both sides of the cutting groove, and the width of the cutting groove is likely to be large.

  On the other hand, when the substrate is heated and cut with a laser, the cost of the apparatus becomes high, and especially SiC and sapphire have particularly high heat conductivity, so the area around the laser-irradiated portion becomes extremely hot and may deteriorate device performance. There is. Also, when cutting with a laser, the groove is likely to be wider than when cutting with a diamond blade as a result of running the laser several times along the cutting location.

  The present invention provides a long-life diamond blade capable of processing with high precision even with a narrow groove width while suppressing generation of chipping when cutting or cutting a substrate made of a hard material such as silicon carbide, and a method for manufacturing the same. The purpose is to do.

In the present invention, the following diamond blade and the manufacturing method thereof are provided.
<1> A diamond blade comprising an annular or disk-shaped metal base and a group of diamond particles grown on at least the outer periphery of the base.
<2> The diamond blade according to <1>, wherein the base material is made of molybdenum, tantalum, or an alloy containing molybdenum or tantalum.
<3> A step of removing distortion by annealing an annular or disk-shaped metal substrate, a step of scratching at least an outer peripheral portion of the annealed substrate with diamond powder, and the diamond powder Growing diamond particles on the outer periphery of the scratched substrate.
<4> The method for producing a diamond blade according to <3>, wherein the base material is made of molybdenum, tantalum, or an alloy containing molybdenum or tantalum.
<5> The method for producing a diamond blade according to <3> or <4>, wherein the step of annealing the substrate is performed in hydrogen plasma.
<6> The method for producing a diamond blade according to any one of <3> to <5>, wherein the step of annealing the substrate is performed while being supported with a load applied from both sides of the substrate.
<7> The method for producing a diamond blade according to any one of <3> to <6>, wherein the step of growing the diamond particles is performed by a microwave plasma CVD method.
<8> The method for producing a diamond blade according to any one of <3> to <7>, wherein the step of scratching with the diamond powder is performed by ultrasonically treating the substrate in a medium containing the diamond powder.

  ADVANTAGE OF THE INVENTION According to this invention, the long-life diamond blade which can be processed with high precision by a thin groove width, suppressing generation | occurrence | production of chipping, and its manufacturing method are provided.

It is a microscope image which shows the outer edge part of the cyclic | annular molybdenum base material in which the diamond particle was grown. It is a figure which shows an example of the process of the method of manufacturing the diamond blade which concerns on this invention. It is the schematic which shows an example of a structure of the microwave plasma CVD apparatus which grows a diamond particle. It is a figure which shows an example of the holding jig used when growing a diamond particle on the outer peripheral part of a base material. It is a figure which shows the other example of the holding jig used when growing a diamond particle on the outer peripheral part of a base material. It is a microscope image which shows the outer peripheral part which made the diamond particle grow. It is a figure which expands and shows the area | region shown by A of FIG. It is a figure which expands and shows the area | region shown by A of FIG. 5 after performing the growth of a diamond particle twice. It is a microscope image which shows the groove | channel formed by cutting a SiC substrate with the diamond blade which concerns on this invention. It is the schematic which shows the state which made the diamond particle group grow in the outer peripheral part of a base material.

<Diamond blade>
The diamond blade according to the present invention includes an annular or disk-shaped metal base and a group of diamond particles grown on at least the outer periphery of the base.

  FIG. 1 is a laser microscope image showing an example of a diamond blade according to the present invention. In this diamond blade, a group of polycrystalline diamond particles having a particle diameter of about 1 μm to 10 μm is grown and arranged on the outer peripheral portion of a cyclic molybdenum substrate (referred to as “Mo ring” as appropriate). In this way, if the diamond blade is a group of diamond particles grown on the outer peripheral surface of the Mo ring, the diamond particles have no cracks caused by crushing and have a very high hardness, so that cutting or cutting of a hard material such as SiC is performed. Even if it uses it, it can process efficiently and generation | occurrence | production of chipping can be suppressed effectively. Moreover, since diamond particles have high adhesion to the Mo ring and do not easily fall off, they can be used for a long period of time. Furthermore, since the diamond particle group is directly formed on the surface of the Mo ring without using a resin or the like, it can be grooved with a narrow groove width.

-Base material-
As the base material constituting the diamond blade according to the present invention, a disc-like or annular one having a circular outer periphery can be adopted. However, the annular base material is used in view of material cost, attachment to an existing dicing apparatus, and the like. It is preferable that

  The base material is made of, for example, molybdenum or tantalum. If the base material is made of molybdenum or tantalum, it has mechanical strength as a support for the blade and can grow diamond particles on the surface of the base material with high adhesion strength. The substrate may contain other components as long as the content of molybdenum or tantalum is the highest, such as molybdenum or an alloy containing tantalum, but the composition of molybdenum is from the viewpoint of mechanical strength and diamond particle growth. The closer to 100%, the better.

  The thickness of the substrate is not particularly limited, but the thickness at the outer peripheral portion is more preferably 20 μm or more and 50 μm or less from the viewpoint of having mechanical strength as a blade and reducing the grinding width.

  Further, the outer diameter of the substrate is preferably 2 cm or more and 20 cm or less, preferably 2 cm or more and 5.5 cm or less from the viewpoints of handleability as a blade, suppression of manufacturing costs, compatibility with a general dicing apparatus, and the like. It is more preferable that

-Diamond particle group-
A group of polycrystalline diamond particles grown on the surface of the outer peripheral portion of the base material is disposed in close contact with the outer peripheral portion of the base material that is the blade tip portion of the blade.
In addition, in this specification, the outer peripheral part of the base material in which the grown diamond particle group is arranged means an outer edge part (end face) and inner areas on both sides along the outer edge part. From the viewpoint of suppressing the occurrence of chipping on both sides of the blade when cutting the workpiece, the diamond particle group is preferably arranged from the outer edge (edge portion) to an inner region of 1 mm or more, more preferably 3 mm or more. Is desirable.

The particle size of the diamond particles constituting the diamond particle group depends on the object to be processed, but when using a diamond blade for cutting SiC wafers, it ensures cutting performance and efficiently cuts and generates chipping. From the viewpoint of effectively suppressing the average particle size, the average particle size is preferably 1 μm to 20 μm, more preferably 1 μm to 10 μm.
The particle size of the diamond particles can be obtained from the value measured with a laser microscope. Specifically, when a substrate on which diamond particles are grown is observed with a laser microscope (magnification: 1000 times), the diameter of the smallest circle surrounding each diamond particle (that is, the maximum passing diameter) is the diameter of the diamond particle. The particle size. The average particle diameter is an average value calculated from 100 values arbitrarily extracted by measuring the maximum length of each diamond particle grown on the outer peripheral portion of the substrate.

  The thickness of the diamond particle group is preferably 1 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less from the viewpoint of achieving high cutting ability.

<Diamond blade manufacturing method>
Next, a method for manufacturing a diamond blade according to the present invention will be described. The following manufacturing method is an example, and the manufacturing of the diamond blade according to the present invention is not limited to the following manufacturing method.
FIG. 2 shows a process of an example of a method for manufacturing a diamond blade according to the present invention.

  The method for producing a diamond blade according to the present invention includes a step of removing distortion by annealing an annular or disk-shaped metal substrate, and scratching at least the outer periphery of the annealed substrate with diamond powder. And a step of growing diamond particles on the outer periphery of the substrate scratched by the diamond powder.

(A) Annealing process First, distortion is removed by annealing a metal substrate.
As described above, molybdenum or tantalum or an alloy containing molybdenum or tantalum is preferably used as the base material to be the support of the diamond blade, and molybdenum is particularly preferable. The shape, outer diameter, and thickness of the substrate are as described above. In addition, when the thickness of the substrate is too thin, the thickness is preferably 20 μm or more and 50 μm or less from the viewpoint that warpage is likely to occur when the substrate is exposed to a high temperature by annealing.

The conditions for annealing the substrate vary depending on the material and thickness of the substrate, but for example, annealing is performed in hydrogen plasma at a temperature of 1055 ° C. or more and 1270 ° C. or less for 5 minutes or more. The upper limit of the annealing time is not limited, but is preferably 10 minutes or less from the viewpoint of productivity.
By annealing the base material under such conditions, the strain is removed, and deformation (warping, strain, etc.) of the base material in the subsequent diamond particle growth step is suppressed. The atmosphere during annealing is not particularly limited as long as the formation of a thin film that inhibits the growth of diamond particles such as an oxide film and a nitride film is suppressed. However, diamond particles such as an oxide film and a nitride film are used in a hydrogen plasma. The substrate can be annealed while suppressing the formation of a thin film that inhibits the growth of the substrate. In order to suppress deformation (warp, distortion, etc.) of the substrate even when the annealing treatment is performed, it is preferable to support the substrate in a state where a load is applied from both sides of the substrate.

  In the annealing step, the distortion of the base material is removed to suppress the deformation of the base material more effectively in the diamond particle growth step, and the temperature is lower than the melting point of the base material. It is preferable to perform annealing at a temperature of 1270 ° C. or lower for 5 minutes to 10 minutes.

(B) Scratching step with diamond powder Next, at least the outer peripheral portion of the annealed substrate is scratched (seeded) with diamond powder (fine particles).
The particle diameter of the diamond powder used for scratching is preferably 0.5 μm or more and 100 μm or less from the viewpoint of reliably growing diamond particles in the next step using the diamond powder component adhering to the substrate as a seed.

The method of scratching the outer peripheral portion of the substrate with diamond powder is not particularly limited, but it is preferable to perform the ultrasonic treatment of the substrate in a medium containing diamond powder. With such a method, the outer peripheral portion of the base material can be easily and reliably scratched with the diamond powder, and the diamond particles grown starting from the components of the diamond powder used for scratching are formed on the outer peripheral portion of the base material. It adheres firmly and does not easily fall off even when a large load is applied when cutting a hard material such as a SiC substrate.
Examples of the solvent used for ultrasonic treatment at the time of scratching with diamond powder include alcohol, acetone and the like.
In addition, the method of scratching the outer peripheral part of a base material is not limited to the above ultrasonic treatment, For example, you may scratch a diamond powder by rubbing on the outer peripheral part of a base material.

(C) Diamond particle growth process Next, a diamond particle is made to grow in the outer peripheral part of the base material scratched with the diamond powder.
The growth of diamond particles is preferably performed by a microwave plasma CVD method.
The microwave plasma CVD apparatus to be used is not particularly limited as long as it has a microwave waveguide, a gas introduction port for plasma generation, and a plasma discharge chamber by microwave excitation. For example, as shown in FIG. An apparatus 10 having a configuration can be used. The apparatus 10 has a support base (holder) 18, a gas introduction port 14 provided above the support base 18, and an exhaust port 16 provided below the support base 18 in the chamber 12. .
The support base 18 is disposed at a substantially central position in the chamber 12 so that the raw material gas introduced into the chamber 12 from the plurality of gas inlets 14 flows uniformly on the surface of the base material 30. Moreover, the support base 18 has a heating means (heater) for heating the base material 30, and the support column 20 that supports the support base 18 has a function of cooling water by circulating water therein.

  A microwave generating means 22 is provided above the chamber 12. The microwave output affects the plasma region. By increasing the output, polycrystalline diamond particles can be grown on the entire outer periphery of the substrate 30 even when the substrate 30 having a relatively large area is used.

When performing diamond growth using such a microwave plasma CVD apparatus 10, in order to suppress deformation of the base material, the outer peripheral portion of the base material scratched with diamond powder is exposed and a load is applied from both sides. It is preferable to do.
For example, as shown in FIG. 4A, in the support base 18 having a circular accommodating portion 19, the Mo ring 30 is sandwiched between upper and lower holding members (laying plate 32, weight plate 34) made of Mo. To do. At this time, the outer peripheral portion of the upper surface of the Mo ring 30 is exposed from the weight plate 34.

4A, the temperature of the Mo ring 30 can be estimated by measuring the temperature of the weight plate 34 and the support base 18 using a radiation thermometer 36.
From the viewpoint of efficiently growing diamond particles, the surface temperature of the substrate 30 is preferably 850 ° C. or higher and 950 ° C. or lower.
FIG. 4B shows another example of a jig for supporting both surfaces of the substrate. In this jig 40, screw holes 42 </ b> A and 44 </ b> A are respectively provided in the vicinity of the center portion of a molybdenum laying plate (lower plate) 42 and a weight plate (upper plate) 44. By integrating with the screw member 46 in a state where the Mo ring 30 is sandwiched between the laying plate 42 and the weight plate 44 so that the outer peripheral portion of the Mo ring 30 is exposed, a high load is applied to both sides of the Mo ring 30. Holds firmly in the hung state. By growing diamond particles in this state, deformation of the Mo ring 30 can be more reliably suppressed.
Further, the screw member 46 is not exposed from the upper surface of the weight plate 44, and the upper surface of the weight plate 44 is formed into a smooth curved surface such as a semicircular shape or a semi-elliptical shape, so that plasma concentration is suppressed and the outer periphery of the Mo ring 30 is Diamond particles can be grown substantially uniformly on the portion.
Note that the holding jig 40 having such a configuration may be used in the annealing step. By holding the Mo ring 30 firmly with the jig 40 and annealing, the deformation of the base material 30 can be effectively suppressed.

  After the Mo ring 30 is disposed on the support base 18, a raw material gas is flowed from the gas inlet 14 to generate plasma to raise the temperature so that the temperature of the substrate 30 becomes a predetermined temperature (for example, 900 ° C.). Adjust pressure, microwave output, etc. Here, a mixed gas containing methane and hydrogen at a certain ratio is used as the source gas.

  Hydrogen gas contributes to carrier gas, substrate etching, growth particle etching, fine particle growth suppression, promotion of methane molecularization into plasma, and the like. If the hydrogen concentration is too low, the growth of ultrafine particles becomes prominent and clogging is likely to occur, and problems such as chipping of the tips of the diamond particles are likely to occur. On the other hand, if the hydrogen concentration is too high, the etching rate for the grown diamond is increased and the growth of ultrafine particles is suppressed. Or the edges of the diamond particles may become flat and the grinding ability may decrease.

  As a result of repeating the experiment on the raw material gas concentration, the present inventor has found that the concentration (flow rate ratio) of each component in the raw material gas is preferably 1% to 10% for methane, 90% to 99% for hydrogen, and more. Preferably, by performing microwave plasma CVD using a source gas containing methane in a range of 1% to 5% and hydrogen in a range of 95% to 99%, diamond particles having a small variation in particle diameter are efficiently grown. I found that I can do it.

  The pressure in the chamber 12 affects the input gas amount, and depends on the target diamond particle size and number density (occupancy), but is set to 50 to 200 Torr, for example.

  The microwave output varies depending on the size of the chamber 12, but is set to 3 to 5 kW, for example.

The processing time (growth time) also depends on the target diamond particle size and number density (occupancy), but for example, diamond growth is 0.5 to 8 hours per side, that is, 1 to 16 hours on both sides. As a result, a group of diamond particles having a particle size of about 1 to 10 μm is densely formed.
In the diamond particle growth step, diamond particles are grown on the outer peripheral portion of one side of the Mo ring 30, and then the Mo ring 30 is turned upside down and held by the jig 40 again to grow the diamond particles again. Thereby, as shown in FIG. 9, diamond particle groups 50 are formed on both sides of the outer peripheral portion of the Mo ring 30.

By growing diamond on the outer peripheral portions of both surfaces of the substrate 30 as described above, as shown in FIG. 1, a diamond blade (diamond having a diamond particle group having an average particle diameter of 1 μm or more and 10 μm or less is formed. Cutter).
The obtained diamond blade can be suitably used for cutting and cutting of a SiC substrate, a sapphire substrate, etc., for example, by fixing to a rotating shaft and setting it on a dicing apparatus.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

<Example 1>
-Annealing-
A ring made of molybdenum (outer diameter 52 mm, thickness 50 μm) was prepared and annealed under the following conditions.
Atmosphere: Hydrogen plasma Temperature: 1055 to 1270 ° C. (There is temperature unevenness in the ring)
Time: 5 minutes

-Scratch-
After annealing, the Mo ring was scratched with diamond powder. 0.3 g of diamond powder (product name: “0-2”, particle size: 0.9 μm) was added to 20 ml of isopropyl alcohol (IPA), and a Mo ring was immersed in this to perform ultrasonic cleaning (20 minutes).

-Diamond growth-
A Mo ring was installed directly on the sample holder (no laying plate / overlap plate), and diamond particles were grown under the following conditions:
Microwave output: 5kW
Chamber pressure: 60 Torr
Source gas (sccm): H ₂ : CH ₄ = 500: 10
Substrate temperature: 900 ° C. or less Synthesis time: 30 minutes (one side)
Synthesis average speed: 0.3 μm / hr

  When the diamond particles synthesized on the outer periphery of the Mo ring as described above were observed with a laser microscope, the diamond particles adhered, and the Mo ring maintained elasticity even after the diamond synthesis. Moreover, the average particle diameter of the diamond particles was 10 μm.

  FIG. 5 is a laser microscope image obtained by photographing the vicinity of the outer peripheral portion of the Mo ring on which diamond particles are grown. FIG. 6 is an enlarged view of the region indicated by A in FIG. 5, and FIG. 7 is an enlarged view of the region indicated by A in FIG. 5 after the diamond particles are grown twice. It can be seen that the diamond particles are densely formed on the outer periphery of the Mo ring.

-Cutting evaluation-
The obtained diamond blade was set in a dicing apparatus (manufactured by Tokyo Seimitsu Co., Ltd., product name: automatic dicing machine 2500A / T type), and a SiC substrate (diameter: 3 inches, thickness: 350 μm) was cut under the following conditions.
Blade rotation speed: 30,000 rpm
Feed rate: 1 mm / sec Cut mode: Down cut Depth of cut: 0.1 mm per stroke
The SiC wafer was subjected to a total of 5 cutting tests with a length of 10 mm under the above processing conditions (0.1 mm × 1 once, 0.1 × 2 twice, 0.1 mm × 3 twice).

When the cutting groove was observed with a microscope, the occurrence of chipping was greatly reduced as the number of cuttings increased as shown in FIG. Cutting grooves with a width of about 60 μm were formed, and there was almost no occurrence of chipping.
In the diamond blade of Example 1, relatively large diamond particles were also grown on the outer periphery of the Mo base, but the huge particles dropped off during the initial grinding, and the diamond particles effective for cutting increased relatively. It is thought that the occurrence of chipping was suppressed.
Moreover, even if it cut 100 times, except for a huge diamond particle, it hardly dropped out and the cutting ability hardly decreased.

As mentioned above, although embodiment and the Example were described, the diamond blade which concerns on this invention, and its manufacturing method are not limited to the said embodiment and Example.
For example, the workpiece using the diamond blade according to the present invention is not limited to a SiC substrate, but is suitable for a sapphire substrate, for example, and may be used for cutting other difficult-to-work materials.

DESCRIPTION OF SYMBOLS 10 Microwave plasma CVD apparatus 12 Chamber 14 Gas introduction port 16 Exhaust port 18 Support stand (sample holder)
20 Prop 22 Microwave generator 30 Base material (ring)

Claims (8)

An annular or disk-shaped metal substrate;
A group of diamond particles grown on at least the outer periphery of the substrate;
Including diamond blade.   The diamond blade according to claim 1, wherein the substrate is made of molybdenum, tantalum, or an alloy containing molybdenum or tantalum. Removing the strain by annealing the annular or disk-shaped metal substrate; and
Scratching at least the outer periphery of the annealed substrate with diamond powder;
Growing diamond particles on the outer periphery of the substrate scratched by the diamond powder;
A method for producing a diamond blade comprising:   The diamond blade manufacturing method according to claim 3, wherein the base material is made of molybdenum, tantalum, or an alloy containing molybdenum or tantalum.   The method for producing a diamond blade according to claim 3 or 4, wherein the step of annealing the substrate is performed in hydrogen plasma.   The method for producing a diamond blade according to any one of claims 3 to 5, wherein the step of annealing the base material is performed with a load applied from both sides of the base material.   The method for producing a diamond blade according to any one of claims 3 to 6, wherein the step of growing the diamond particles is performed by a microwave plasma CVD method.   The method for producing a diamond blade according to any one of claims 3 to 7, wherein the step of scratching with the diamond powder is performed by ultrasonically treating the base material in a medium containing the diamond powder.