JP2022145324A - Vitrified tool and manufacturing method thereof - Google Patents

Abstract

To provide a vitrified tool which employs diamond as abrasive grains, realizes high surface roughness of a material polished therewith, and hardly causes scratches.SOLUTION: The vitrified tool comprises a substrate 15, and a bond layer 5 disposed on the substrate 15 and comprising a vitreous material retaining innumerable abrasive grains 1. Each abrasive grain 1 is of diamond. The bond layer 5 contains 10.6 mol% or more of bismuth oxide.SELECTED DRAWING: Figure 1

Description

The present invention relates to vitrified tools and methods of making the same.

A vitrified tool comprises a base material and a vitreous bond layer holding countless abrasive grains. There are cases where a bond layer holding countless abrasive grains is manufactured as a chip and the chip is fixed on a substrate, and there is a case where a bond layer holding countless abrasive grains is directly fixed on the substrate. The bond layer may or may not contain pores. In addition, Patent Document 1 discloses a technique of impregnating the pores in the bond layer with a resin in order to improve the holding power of abrasive grains in this vitrified tool.

For example, the vitrified tool is embodied as a grinding tool and used during grinding operations. A vitrified tool has the characteristic that the surface density of abrasive grains on the polishing surface and the size of the abrasive grains can be easily adjusted during manufacture.

International publication 2006/090527

However, since vitrified tools are used to process difficult-to-cut materials such as semiconductor wafers, cemented carbide, and ceramics, when diamond, which has the highest hardness, is used, the surface roughness of the mating materials after polishing is low. At the same time, scratches are likely to occur. This is because the wettability between the diamond and the vitreous is low, and the state of holding the diamond and the bond layer tends to differ, so the diamond is scattered and the grinding state tends to vary.

The present invention has been made in view of the above-mentioned conventional circumstances, and provides a vitrified tool that employs diamond as abrasive grains, has a high surface roughness of the mating material after polishing, and is less prone to scratches. are issues to be resolved.

The vitrified tool of the present invention comprises a base material, and a vitreous bond layer provided on the base material and holding countless abrasive grains,
each said abrasive grain is a diamond,
The bond layer is characterized by containing 10.6 mol % or more of bismuth oxide.

According to the inventor's test, the vitrified tool of the present invention has a vitreous bond layer containing 10.6 mol % or more of bismuth oxide (Bi ₂ O ₃ ) while each abrasive grain is diamond. , the bond layer exhibits high wettability to diamond. For this reason, the holding state of the diamond and the bond layer is unlikely to be different, and the diamond tends to be evenly distributed, so that the grinding state is less likely to vary.

The method for producing a vitrified tool of the present invention comprises a first step of preparing a mixture containing a composition containing 10.6 mol % or more of bismuth oxide and forming a glassy substance, and countless abrasive grains made of diamond;
a second step of obtaining a molded body of the mixture;
and a third step of firing the compact in an oxidizing atmosphere to retain the abrasive grains with the vitrified material of the composition to obtain a vitrified tool.

The vitrified tool of the present invention can be manufactured by the manufacturing method of the present invention.

According to the vitrified tool of the present invention, while employing diamond as abrasive grains, the surface roughness of the mating material after polishing is high, and scratches are less likely to occur.

FIG. 1 is a schematic enlarged cross-sectional view of a chip such as an example. FIG. 2 is a graph showing the relationship between temperature and elongation of compositions used in Examples and the like. FIG. 3 is an XRD measurement result showing the crystallinity of the compositions used in Examples and the like. FIG. 4 is a perspective view of a grinding tool that is an example of the vitrified tool of the embodiment. FIG. 5 is a photomicrograph showing the side surface of the bond layer using the slurry of test article 1 in test 2. FIG. FIG. 6 is a photomicrograph showing a cross section of a bond layer using the slurry of test product 1 in test 2. FIG. FIG. 7 is a photomicrograph showing the side surface of the bond layer using the slurry of test article 6 in test 2. FIG. FIG. 8 is a photomicrograph showing a cross section of the bond layer using the slurry of test product 6 in test 2. FIG. FIG. 9 is a perspective view of another grinding tool. FIG. 10 is a perspective view of another grinding tool.

The base material may be a rigid base material or a flexible base material that does not deform the bond layer holding countless abrasive grains. As the substrate having rigidity, ceramics such as alumina, silicon nitride, silicon carbide, zirconia, mullite, metals such as iron, SUS, copper, glass having a strain point of 600° C. or higher, and the like can be used. Examples of flexible substrates include sheets made of woven fabrics or non-woven fabrics made of fibers such as natural fibers, synthetic fibers, and carbon fibers, polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyimide ( PI), polyethylene naphthalate (PEN), a synthetic resin such as aramid, or a single-layer or multi-layer film made of a metal such as aluminum or copper.

As a glassy bond layer, a frit-containing composition such as borosilicate glass can be minimized. The composition can be a slurry or powder. A mixture containing the composition and a myriad of abrasive grains of diamond can also be a slurry or powder. By forming the mixture into a molded body, drying the molded body if necessary, and melting and solidifying the composition, the composition constitutes a glassy substance.

The mixing ratio (volume) of vitreous and diamond in the bond layer is preferably 80:20 to 10:90, more preferably 60:40 to 25:75. A pore former or the like may be added to the mixture to adjust the porosity of the bond layer.

The abrasive grain used in the vitrified tool of the present invention is diamond. The grain size of diamond is set variously according to the use of the vitrified tool.

According to the inventor's test results, the effect of the present invention can be obtained if the bond layer contains 10.6 mol % or more of bismuth oxide, but if the bond layer contains 28.6 mol % or more of bismuth oxide, It is more preferable to be In terms of % by mass, the effect of the present invention can be obtained if the bond layer contains 40.6% by mass or more of bismuth oxide, but the bond layer contains 71.1% by mass or more of bismuth oxide. is more preferable. In this case, the bond layer has high wettability with diamond.

Bond layers may contain _SiO2 , _{Al2O3 , B2O3 ,} alkali oxides and alkaline earth oxides, as well as bismuth oxide. SiO ₂ is preferably 4.8 mol % or more and 25.4 mol % or less. In terms of % by mass, SiO ₂ is preferably 1.4% by mass or more and 12.6% by mass or less. Al ₂ O ₃ is preferably 0.8 mol % or more and 4.4 mol % or less. In terms of mass %, Al ₂ O ₃ is preferably 0.4 mass % or more and 3.7 mass % or less. B ₂ O ₃ is preferably 21.0 mol % or more and 31.1 mol % or less. In terms of % by mass, B ₂ O ₃ is preferably 7.8% by mass or more and less than 14.4% by mass. The alkali oxide content is preferably 0.1 mol % or more and 0.2 mol % or less. In terms of mass %, the alkali oxide content is preferably 0.1 mass % or less. Alkaline earth oxides are preferably 27.0 mol % or more and 34.4 mol % or less. In terms of % by mass, the content of alkaline earth oxides is preferably 10.7% by mass or more and 28.7% by mass or less.

Further, according to the inventor's test results, the bond layer preferably has a softening point of 391° C. or higher and 549° C. or lower. The bond layer preferably has a softening point of 522°C or less, particularly 436°C or less. In this case, the bond layer has high wettability with diamond.

Furthermore, according to the inventor's test results, the bond layer preferably has a degree of crystallinity of 90% or less. In this case, the bond layer has high wettability with diamond. The bond layer preferably has a degree of crystallinity of 70% or less, more preferably 8% or less.

According to the test results of the inventors, in the production method of the present invention, the oxidizing atmosphere preferably has an oxygen concentration of 0.01 to 20% without introducing a reducing gas such as hydrogen into the firing chamber. If a reducing gas is introduced into the firing chamber or if the oxygen concentration is less than 0.01%, the bismuth oxide in the composition will be reduced, and the bond layer will not be able to exhibit suitable wettability to diamond abrasive grains. If the oxygen concentration exceeds 20%, the abrasive grains of diamond tend to disappear, depending on the relationship with the firing time.

In the production method of the present invention, in the third step, it is preferable to bake the substrate compact at 585° C. or lower. This is because, according to the inventor's test results, the vitrified tool of the present invention was obtained with a composition having a yield point of 585°C. In this case, depending on the relationship with the firing time, the abrasive grains of diamond are unlikely to disappear, and the bond layer has high wettability with the diamond. In the third step, it is more preferable to bake the base compact at 467° C. or lower.

Hereinafter, the present invention will be explained by Tests 1 to 3, and Examples 1 to 5 and a Comparative Example will be explained.

(Test 1)
In Test 1, the composition of the composition was changed variously, and as shown in FIG. In each chip 20, countless abrasive grains 1 are held on a bond layer 5 made of vitreous. The bond layer 5 contains pores 7 and has abrasive grains 1 in multiple layers.

First, in the first step, compositions 1 to 7, countless abrasive grains 1 (diamond, average particle size: 0.5 μm), binder resin (acrylic resin), and solvent (alcohol) were prepared. Table 1 shows the mol % of compositions 1 to 7 in terms of vitrification, and Table 2 shows the mass %. The lower part of Table 1 shows the mol % of alkali oxides and alkaline earth oxides, and the lower part of Table 2 shows the mass % of alkali oxides and alkaline earth oxides.

TMA measurements were performed on each of Compositions 1-7. As illustrated in FIG. 2, each of Compositions 1 to 7 melts when the temperature is raised, so it exhibits a softening point Tg (°C) and a sag point Ts (°C). In addition, as shown in FIG. 3, each composition 1 to 7 was evaluated by an XRD evaluation device ("Smartlab" manufactured by rigaku) to determine the degree of crystallinity. These results are shown in Table 3.

Compositions 1 to 7 and abrasive grain 1 were placed in a ball mill, and the ball mill was rotated. Thus, slurries of test products 1 to 7 were obtained. The mixing ratio (volume) of the vitreous material of the bond layer 5 and the abrasive grains 1 was 30:70.

In the second step, each slurry was formed into a chip shape, and the solvent was evaporated to form a compact.

As a third step, each compact was fired for a predetermined time to obtain a chip 20 . Chip 20 could not be produced with the slurry of test article 7. Table 4 shows the gas species, oxygen concentration (%) and atmosphere in the firing chamber at this time.

As shown in FIG. 4, chips 20 obtained from slurries of test pieces 1 to 5 were bonded to a base metal 15 made of an aluminum alloy as a base material to form a grinding tool. In one cutting tool, chips 20 manufactured with the same slurry are joined.

(Test 2)
In Test 2, the wettability between the abrasive grains 1 and the bond layer 5 was confirmed. First, slurries of test products 1 to 6 were applied to a thickness of about 10 μm on an alumina substrate. rice field. After firing, how much the abrasive grains 1 were embedded in the bond layer 5 made of the slurry of the specimens 1 to 6 was evaluated according to the following criteria.
◎: Bond layer 5 is 50% or more of the diameter of the abrasive grain 1 ○: Bond layer 5 is 10% or more of the diameter of the abrasive grain 1 ×: Bond layer 5 is less than 10% of the diameter of the abrasive grain 1

FIG. 4 shows a photomicrograph of the side surface of bond layer 5 using the slurry of test product 1, and FIG. 5 shows a photomicrograph of its cross section. On the other hand, FIG. 6 shows a microphotograph of the side surface of the bond layer 5 using the slurry of test product 6, and FIG. 7 shows a microphotograph of its cross section.

As shown in FIGS. 4 and 5, when the slurry of the test product 1 is used, the black diamond abrasive grains 1 are embedded in the white bond layer 5 . Moreover, when the slurry of test product 1 was used, it can be seen that the bond layer 5 was well coated around the abrasive grains 1 . This is because the bond layer 5 made of the slurry of Comparative Example 1 has high wettability with respect to the abrasive grains 1 made of diamond. The same is true when the slurries of test items 2 to 5 are used.

On the other hand, as shown in FIGS. 6 and 7, when the slurry of test product 6 was used, abrasive grains 1 were exposed from bond layer 5 . Moreover, when the slurry of the test product 6 was used, there were places where the abrasive grains 1 were scattered, and it was found that the state of grinding was likely to vary.

(Test 3)
A grinding tool for evaluation was prepared using each tip 20 obtained from the slurries of test products 1 to 6. The evaluation grinding tools using the tips 20 obtained with the slurries of the test products 1 to 5 are the vitrified tools of Examples 1 to 5, and the evaluation grinding tools using the tips 20 obtained with the slurry of the test product 6. is a comparative vitrified tool. A Si wafer was ground with each evaluation grinding tool, and the surface roughness of the wafer after grinding was confirmed with a surface roughness meter (Zygo) and evaluated under the following conditions.
◎: Sa = less than 2 nm ○: Sa = less than 3 nm ×: Sa = 3 nm or more

Furthermore, it was confirmed whether or not there was a scratch with a depth of 20 nm or more on the wafer after grinding. These results are shown in Table 5.

As is clear from Table 5, the bond layers 5 of the evaluation grinding tools of Examples 1 to 5 have high wettability even though the abrasive grains 1 are diamond. In particular, the bond layers 5 of the evaluation grinding tools of Examples 1 and 2, in which the bond layers 5 contain 28.6 mol % or more of bismuth oxide, exhibit excellent wettability. Therefore, it can be seen that the vitrified tool using the tip 20 having these bond layers 5 employs diamond as the abrasive grains 1 and is also excellent in polishability and scratch resistance. This is because it contains a specific amount or more of bismuth oxide. This is also because these bond layers 5 have a softening point of 391° C. or more and 549° C. or less and a degree of crystallinity of 90% or less.

The tips 20 of Examples 1-5 can also be embodied in the grinding tools of FIGS. The grinding tool shown in FIG. 9 employs a rod-shaped base metal 17 and a plurality of tips 20 are adhered to the peripheral surface of this base metal 17 . The grinding tool shown in FIG. 10 employs a plate-shaped base metal 19 and a plurality of tips 20 are bonded to one surface of this base metal 19 .

Therefore, the vitrified tools of Examples 1 to 5 are capable of machining difficult-to-cut materials with a tool that rotates at high speed.

In the above, the present invention was described in accordance with Tests 1 to 3 and Examples 1 to 5, but the present invention is not limited to the above Tests 1 to 3 and Examples 1 to 5, and deviates from the gist thereof. Needless to say, it can be appropriately changed and applied to the extent that it does not occur.

In the above embodiment, the bond layer 5 holding countless abrasive grains 1 is manufactured as the tip 20, and the tip 20 is fixed on the base material. The bonded bond layer 5 may be directly fixed on the substrate. Further, the bond layer 5 may have the abrasive grains 1 in multiple layers on the substrate as in the embodiment, or may have the abrasive grains 1 in a single layer on the substrate. Furthermore, although the bond layer 5 has the pores 7 in the above embodiment, the bond layer 5 may have no pores 7 and be densely structured. In the vitrified tool of the present invention, if only a single layer of abrasive grains is fixed on the substrate, the bond layer is preferably dense and substantially free of pores.

INDUSTRIAL APPLICABILITY The present invention can be used for grinding tools and the like.

15 Base material (base metal)
5... Bond layer 1... Abrasive grain

Claims (6)

A base material and a vitreous bond layer provided on the base material and holding countless abrasive grains,
each said abrasive grain is a diamond,
A vitrified tool, wherein the bond layer contains 10.6 mol % or more of bismuth oxide. A vitrified tool according to claim 1, wherein said bond layer contains 28.6 mol% or more of bismuth oxide. 3. The vitrified tool according to claim 1, wherein said bond layer has a softening point of 391[deg.] C. or more and 549[deg.] C. or less. The vitrified tool according to any one of claims 1 to 3, wherein the bond layer has a crystallinity of 90% or less. a first step of preparing a mixture containing a composition containing 10.6 mol % or more of bismuth oxide and forming a glassy substance and countless abrasive grains made of diamond;
a second step of obtaining a molded body of the mixture;
and a third step of firing the compact in an oxidizing atmosphere so that the abrasive grains are held by the vitrified material of the composition to obtain a vitrified tool. . 6. The method of manufacturing a vitrified tool according to claim 5, wherein in said third step, said compact is fired at 585[deg.] C. or less.

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