KR101158303B1 - Diamond Tools for Grinding Brittle Materials Having High Hardness - Google Patents

Abstract

The present invention relates to a diamond tool for processing a high hardness, high brittle wafer material such as sapphire, ceramics, etc., a diamond tool that can polish a high hardness, high brittle material with a micro hardness of 2,000kg / mm ² or more without breaking with a small load I want to provide it, and its purpose is.

The present invention includes a metal bond layer, abrasive grains and fillers; The fillers are vitreous carbon particles having a hardness of 2.5 to 3.5 GPa and an elastic modulus of 25 to 80 GPa, the content of which is 5 to 30 vol% by volume ratio; Vitreous carbon particles having a size equal to or larger than the abrasive grains are 20 to 100 vol% of the total vitrification carbon particle content; The number of vitreous carbon particles having the same protruding height from the abrasive grains and the surface of the metal bond layer during polishing is equal to or greater than the number of abrasive grains; the hardness and the tensile strength of the metal bond layer are HRB 76-90 and 5-20 kg /, respectively. The diamond tool for processing a high hardness, high brittle material of 2mm2 is made into the summary.

INDUSTRIAL APPLICABILITY The present invention can be effectively used for the processing of high hardness and high brittle materials such as sapphire and ceramics used in wafers such as compound semiconductors and LED lighting.

Superabrasive, Diamond Tool, Filler, Vitreous Carbon, Spherical

Description

Diamond Tools for Grinding Brittle Materials Having High Hardness

The present invention relates to a diamond tool for processing a high hardness and high brittle material such as sapphire, ceramic, etc. used in wafer materials such as compound semiconductors, LED lighting, etc. More specifically, the workpiece hardness is 2,000kg / mm ² in micro hardness The present invention relates to a diamond tool for high hardness and high brittle material processing for processing a high hardness and high brittle wafer material such as sapphire, ceramic and the like used in the above wafer materials.

Usually, a diamond tool is comprised with abrasive grains, such as a diamond particle which serves to grind or cut a workpiece | work, and the metal bond layer which fixes this abrasive grain.

The polishing of the workpiece by the diamond tool is performed by the exposed abrasive grains, and the metal bond layer exposes the abrasive grains by contacting the workpiece during polishing of the workpiece, thereby exposing the abrasive grains continuously. .

In order to reduce the heat of polishing generated during polishing of the workpiece by the diamond tool and to improve the lubrication characteristics, a filler such as natural carbon powder, MoS ₂ , alumina (Al ₂ O ₃ ), glassy carbon, or the like is added to the metal bond layer. Diamond tools have been proposed.

However, such conventional diamond tools have been applied to processing materials having relatively high ductility and toughness, such as general steel and cast iron.

However, in recent years, in addition to the polishing of relatively high ductility and toughness materials such as general steel and cast iron, polishing of the workpiece by diamond tools has been required in a new industrial field.

As an example, grinding | polishing of high hardness high brittle material, such as sapphire, ceramic, etc. used for wafer materials, such as a compound semiconductor and LED illumination, is mentioned.

Such sapphire, ceramic and the like are used as wafer materials as high hardness and high brittle materials having a micro hardness of 2,000 kg / mm ² or more.

Since the sapphire, ceramics, etc. described above are highly brittle, when polishing with a conventional diamond tool, the metal bond layer and the workpiece collide during polishing, and residual stress accumulates in the workpiece, causing frequent breakage of the workpiece. have.

Therefore, there has been a demand for the development of a new diamond tool capable of grinding a high hardness, high brittle material such as sapphire, ceramic, or the like without cracking.

It is an object of the present invention to provide a diamond tool capable of grinding a high hardness, high brittle material having a micro hardness of 2,000 kg / mm ² or more without breaking with a small load.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention is micro hardness 2,000kg / mm ² A diamond tool for processing the above high hardness, high brittle material, comprising: a metal bond layer, abrasive grains, and a filler;

The filler is Vitreous Carbon particles having a hardness of 2.5 to 3.5 GPa and an elastic modulus of 25 to 80 GPa, the content of which is 5 to 30 vol% by volume ratio;

Vitreous carbon particles having a size equal to or larger than the abrasive grains are 20 to 100 vol% of the total vitrification carbon particle content;

The number of vitreous carbon particles having the same protruding height from the abrasive grain and the surface of the metal bond layer during polishing is equal to or greater than the abrasive grain number;

The hardness and the cutting force of the metal bond layer are related to diamond tools for high hardness and high brittle material, characterized in that the HRB 76 ~ 90 and 5 ~ 20kg / ㎜ respectively.

Diamond abrasive grain etc. are mentioned, It is preferable that the abrasive grain has a particle diameter of 32-65 micrometers.

The shape of the vitreous carbon particles is preferably spherical, and the particle size thereof preferably has 10 to 100 µm.

As the metal bond, a metal made of any one of Cu, Co, Fe, Sn, and Ni, or an alloy of these metals is preferably used. The metal bond includes one or more of Ag and P in order to lower the sintering temperature. Two more can be added.

The fraction of pores in the metal bond is preferably 0-5 vol%.

As described above, the present invention can polish the high hardness and high brittle material of micro hardness of 2,000 kg / mm ² or more without breaking with a small load, such as sapphire or ceramics used for wafer materials such as compound semiconductors and LED lighting. It can be effectively used for processing high hardness and high brittle materials.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a diamond tool for processing a high hardness high brittle material for processing a high hardness high brittle material having a micro hardness of 2,000 kg / mm ² or more such as sapphire or ceramic used in a wafer such as a compound semiconductor or an LED light.

The present inventors conducted research and experiments to improve the problem that the cracking (breaking) of the wafers frequently occurs when polishing a high hardness high brittle wafer such as sapphire or ceramic with a conventional diamond tool, and thus, high hardness high brittle wafer When the wafer collides with the metal bond layer of the tool during polishing, it is confirmed that residual stress accumulates in the wafer and cracking of the wafer occurs, and the present invention is proposed based on these results.

The present invention is to prevent the accumulation of residual stress caused by the collision with the metal bond layer to prevent the accumulation of the workpiece material in contact with the metal bond layer of the tool when polishing the high hardness high brittle wafer and By mitigating the impact force, high hardness and high brittle wafers such as sapphire, ceramics and the like can be polished without breaking with a small load, and the type, physical properties and size of the diamond tool filler and the physical properties of the metal bond layer are appropriately specified.

In the present invention, 5 to 30 vol% of Vitreous Carbon particles are added as a filler by volume ratio, and the Vitreous Carbon particles have a hardness of 2.5 to 3.5 GPa and an elastic modulus of 25 to 80 GPa.

The reason for adding vitreous carbon particles having a hardness of 2.5 to 3.5 GPa and an elastic modulus of 25 to 80 GPa as a filler is because the filler has an appropriate hardness, and the abrasive is worn with abrasive grains. It prevents accumulation of residual stress due to collision with the metal bond layer and also reduces the impact force generated during the polishing operation because the filler has an appropriate modulus of elasticity to effectively prevent the cracking of the workpiece in the polishing of high hardness and high brittle materials. This is to prevent.

When the content of the vitreous carbon particles is too small, the above additive effects cannot be sufficiently achieved, and in the case where the content of the vitreous carbon particles is too large, the content of the metal bond layer is relatively low, so that the abrasive grains have poor fixing ability. Because of the fear of early dropout, the content of the vitreous carbon particles is preferably limited to 5 to 30 vol% by volume ratio.

In addition, in the present invention, in order to more reliably maintain a constant distance between the workpiece and the metal bond layer during polishing, the vitreous carbon particles having a size equal to or larger than the abrasive grain should be 20 to 100 vol% of the total vitreous carbon content. More preferably, it is 30-100 vol%.

In addition, the number of vitreous carbon particles having the same protruding height from the abrasive grain and the surface of the metal bond layer during polishing should be equal to or greater than the abrasive grain number.

If the abrasive carbon particles having a size larger than the abrasive grains are less than 20 Vol% of the total abrasive carbon particles content and / or the number of the abrasive carbon particles having the same protrusion height from the abrasive abrasive and metal bond layer surfaces, If the abrasive grains are less than the abrasive grains, the workpiece will likely collide with the metal bond layer, and the workpiece will not be able to maintain a constant distance from the metal bond layer. Can be.

It is preferable that the shape of the said filler is spherical, and the particle diameter has 10-100 micrometers.

In addition, when the vitrification carbon particles are used as the filler, the carbon itself has excellent thermal conductivity and lubricant properties, thereby reducing polishing heat and reducing polishing load.

In order to expose the abrasive grains during polishing, the metal bond layer must be removed. In the present invention, the removal of the metal bond layer is removed by the polishing load when polishing the workpiece. Therefore, the metal bond layer must be peeled from the tool by the polishing load. In order to achieve this, the metal bond layer should have a hardness of HRB 76-90 and a drag force of 5-20kg / mm 2.

In a conventional diamond tool, the removal of the metal bond layer is caused by wear by the work material. Therefore, it is not necessary to limit the hardness and the tensile strength of the metal bond layer. In the case of contact, the wafer is broken.

Therefore, in the present invention, the metal bond layer is configured such that the removal of the metal bond layer during polishing is performed by other than wear by the workpiece.

Diamond abrasive grains etc. are mentioned in this invention, It is preferable that the abrasive grains have a particle size of 32-65 micrometers.

If the abrasive grain size is 35 μm or less, the gap between the workpiece and the metal bond layer may not be sufficiently maintained during polishing, so that the workpiece and the metal bond layer may collide with each other. If the abrasive grain size is larger than 65 μm, the hardness is high. In the case of polishing the brittle material, the brittle fracture of the abrasive grains becomes severe. The broken abrasive pieces cause deep scratches on the inside of the workpiece, thereby increasing the possibility of severe damage to the inside of the material and the surface.

 As the metal bond, a metal made of any one of Cu, Co, Fe, Sn, and Ni, or an alloy of these metals is preferably used. The metal bond includes one or more of Ag and P in order to lower the sintering temperature. Two more can be added.

The fraction of pores in the metal bond is preferably 0-5 vol%.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1)

The filler was added to 450 g of commercially available copper (Cu) powder and 550 g of tin (Sn) powder, 15 vol% of filler and 5 vol% of diamond particles, which are abrasive grains, were placed in a turbulator mixer and mixing was performed for 2 hours.

At this time, as a filler, those having components, hardness, elastic modulus and particle size as shown in Table 1 were used, and the size of the diamond particles was an average of 46 μm (particle size distribution: 40 to 65 μm).

The hardness and the tensile strength of the metal bond layer were HRB 83 and 10.5 kg / mm 2, respectively.

Then, according to the method for producing a diamond tool tip, the mixed powder was cold formed and sintered by hot press at 250 ° C. And the tip produced by the hot press sintering method was bonded to the metal body by the epoxy bond, and the grinding wheel (comparative material (1-6), invention material (1-3)) was produced.

Using a grinding wheel manufactured in the same manner as above, the processing test of the sapphire wafer of brittle material was performed, and the results of the performance test are shown in Table 1 below. In the grinding experiment, grinding equipment of DISCO (manufactured by Japan) was used, and the working speed was 1 to 4 µm / s, and the maximum load (current, A) and average load required during the work by processing five sapphire wafers respectively. (Current, A), the crack of the sapphire wafer which is a workpiece, and the presence of chipping were examined.

Psalm No. filler Filler Properties maximum
Load
(A) Average
Load
(A) Crack / Chipping
Shout
Coefficient
(GPa) Hardness
(GPa)
Granularity Filler content (Vol%) larger than diamond grain size Comparative material 1 Nothing - - - - 15.2 14.2 Chapter 5 Occurrences Comparative material 2 black smoke 10 0.9 10-100 30 12.6 10.5 Chapter 2 Occurrence Invention 1 Vitreous Carbon 30 2.8 10-100 40 9.1 8.1 Nothing Invention Material 2 Vitreous Carbon 68 3 10-100 30 9.5 8.5 Nothing Invention 3 Vitreous Carbon 70 3.5 10-100 20 9.9 8.9 Nothing Comparative material 3 Calnium Arsenic 85 7.5 10-100 30 10.5 9.5 One generation Comparative material 4 Silicon nitride 120 16 10-100 30 10.3 9.4 Chapter 2 Occurrence Comparative material 5 Zirconia 170 11.8 10-100 30 10.9 10.1 Chapter 3 occurrence Comparative Material 6 Alumina 375 14.7 10-100 30 11.9 11.0 Chapter 3 occurrence

As shown in Table 1, it can be seen that the inventive materials (1 to 3) in accordance with the present invention is significantly less cracking and chipping generation than the comparative materials (1 to 6).

In addition, it can be seen that the inventive materials 1 to 3 have lower maximum loads and average load values than the comparative materials 1 to 6.

Inventive materials (1 to 3) have fillers having modulus of elasticity of 30, 68 and 70 GPa. From this, it can be seen that the modulus of elasticity greatly affects the cracking and cracking of the sapphire wafer as the workpiece.

(Example 2)

After the tip was manufactured under the same conditions as the inventive material (1) of Example 1, except that the vitreous carbon particles were changed to 0 to 50 vol% as shown in Table 2, the tip thus prepared was made of a metal body It was bonded to the epoxy bond to prepare a grinding wheel.

Machining test of sapphire, which is a brittle material, was carried out using the grinding wheel manufactured by the above method, and the results of the performance test are shown in Table 2 below.

In the grinding experiment, the grinding equipment of DISCO (manufactured by Japan) was used, and the working speed was 1 to 4 µm / s, and each of five sapphire wafers was processed, and the maximum load (current, A) and average load ( The current, A), cracks in the sapphire, the workpiece, and the presence of chipping were examined.

Psalm No. Vitreous carbon amount (vol%) Load (A) Average load (A) Crack / Chipping Comparative material (7) 0 15.2 14.2 Chapter 5 Occurrence Comparative material (8) 3 13.4 11.9 Chapter 2 Occurrence Invention material (4) 5 10.5 9.8 Nothing Invention material (1) 15 9.1 8.1 Nothing Invention material (5) 30 10.4 9.1 Nothing Comparative material (9) 45 14.1 12.4 Chapter 1 occurrence Comparative material (10) 55 14.7 13.1 Chapter 1 occurrence

As shown in Table 2 above, when the content of the vitreous carbon is 5 to 30 vol% in accordance with the present invention (inventive materials 1, 4 and 5), the load is less than that of the comparative material (7-10) and the cracks are also reduced. It can be seen that chipping does not occur.

(Example 3)

The tip was manufactured under the same conditions as the inventive material (1) of Example 1, except that the hardness and the tensile strength of the metal bond layer were changed as shown in Table 3 below, wherein the metal bond layer was a Cu-Sn-based alloy. Is done.

The tip thus prepared was bonded to the metal body with an epoxy bond to prepare a grinding wheel.

Using the grinding wheel manufactured in the same manner as above, the processing test of the sapphire as a brittle material was performed, and the results of the performance test are shown in Table 3 below.

In the grinding experiment, the grinding equipment of DISCO (manufactured by Japan) was used, and the working speed was 1 to 4 µm / s, and each of five sapphire wafers was processed, and the maximum load (current, A) and average load ( The current, A), cracks in the sapphire, the workpiece, and the presence of chipping were examined.

Psalm No. Hardness (HRB) Drag force (kg / ㎡) Load (A) Average load (A) Crack / Chipping Comparative material (11) 72 3.5 10.8 8.8 Chapter 2 Broken Invention Material (6) 78 6.0 9.0 8.1 Nothing Invention material (7) 80 9.6 9.0 8.1 Nothing Invention material (1) 83 10.5 9.1 8.1 Nothing Invention Material (8) 84 12.7 9.2 8.2 Nothing Invention material (9) 88 16.0 9.3 8.3 Nothing Comparative material (12) 95 45.7 11.8 10.8 3 pieces broken

As shown in Table 3, when the hardness and the tensile strength of the metal bond layer is in accordance with the present invention (Inventive Materials 1, 6 ~ 9), the comparative material (deviating from the hardness and the tensile strength range of the metal bond layer of the present invention) It can be seen that the load is less than in 11 and 12) and cracks and chippings do not occur.

Claims (7)

A diamond tool for processing high hardness, high brittle materials with a microhardness of 2,000 kg / mm ² or more, comprising: a metal bond layer, abrasive grains, and fillers; The filler is Vitreous Carbon particles having a hardness of 2.5 to 3.5 GPa and an elastic modulus of 25 to 80 GPa, the content of which is 5 to 30 vol% in volume ratio; Vitreous carbon particles having a size equal to or larger than the abrasive grains are 20 to 100 vol% of the total vitrification carbon particle content; The number of vitreous carbon particles having the same protruding height from the abrasive grain and the surface of the metal bond layer during polishing is equal to or greater than the abrasive grain number; Hardness and cut strength of the metal bond layer is HRB 76 ~ 90 and 5 ~ 20kg / ㎜, diamond tools for high hardness and high brittle material processing, respectively The diamond tool for processing a high hardness hard brittle material according to claim 1, wherein the abrasive grains are diamond particles. The diamond tool for processing a high hardness and highly brittle material according to claim 2, wherein the diamond particles have a particle diameter of 32 to 65 µm. The diamond tool for processing a high hardness highly brittle material according to any one of claims 1 to 3, wherein the vitreous carbon particles have a spherical shape, and the particle diameter thereof is 10 to 100 µm. The high hardness and highly brittle material according to any one of claims 1 to 3, wherein the metal bond layer is formed of any one of Cu, Co, Fe, Sn, and Ni, or an alloy of these metals. Diamond tools for machining. 6. The diamond tool for hardening highly brittle material according to claim 5, wherein one or two kinds of Ag and P are further added to the metal bond layer. The diamond tool for machining a high hardness and highly brittle material according to any one of claims 1 to 3, wherein the fraction of pores in the metal bond layer is 0 to 5 vol%.