TWI803929B - Saw wire and ingot cutting tool - Google Patents

Abstract

A saw wire adapted for cutting an ingot includes a wire body and abrasive particles disposed on the wire body, wherein a diameter (D50) of each of the abrasive particles is between 5 micrometers and 30 micrometers, and a density of the abrasive particles is between 1000 particles/mm ²to 5000 particles/mm ².

Description

Cutting wire and ingot cutting tools

The present invention relates to a cutting wire and a cutting tool, and in particular to a cutting wire and an ingot cutting tool.

When the crystal ingot with higher hardness is cut into wafers, the material is relatively hard and brittle, which is prone to fragmentation or internal cracking.

The invention provides a cutting wire, which can have good cutting force and can reduce the damage to the wafer.

The present invention provides a crystal ingot cutting tool, which has the above-mentioned cutting line.

A cutting wire of the present invention, suitable for cutting crystal ingots, comprising a wire body and a plurality of abrasive grains arranged on the wire body, wherein the diameter (D50) of each abrasive grain is between 5 microns and 30 microns, and The density of these abrasive grains is between 1000 grains/mm2 and 5000 grains/mm2.

An ingot cutting tool of the present invention includes multiple rows of cutting lines arranged in parallel and at intervals. The cutting wire comprises a wire body and a plurality of abrasive grains disposed on the wire body, wherein the diameter (D50) of each abrasive grain is between 5 microns and 30 microns, and the density of these abrasive grains is between 1000 grains/square mm to 5000 grains/mm2.

In an embodiment of the present invention, the diameter of each of the abrasive grains is between 10 microns and 30 microns, and the density of the abrasive grains is between 1000 grains/mm2 and 3500 grains/mm2.

In an embodiment of the present invention, the diameter of each of the above-mentioned abrasive particles is between 5 microns and 25 microns, and the density of these abrasive particles is between 1200 grains/mm2 and 5000 grains/mm2.

In an embodiment of the present invention, the above-mentioned abrasive grains have a diameter between 20 microns and 30 microns, and the density of these abrasive grains is between 1000 grains/mm2 and 1800 grains/mm2.

In an embodiment of the present invention, the diameter of each of the abrasive particles is between 15 microns and 30 microns, and the density of these abrasive particles is between 1000 grains/mm2 and 2500 grains/mm2.

In an embodiment of the present invention, each of the abrasive grains mentioned above is a diamond grain.

Based on the above, the diameter (D50) of each abrasive grain of the cutting wire of the present invention is between 5 microns and 30 microns, and the density of these abrasive grains is between 1000 grains/square millimeter and 5000 grains/square millimeter . Compared with the diameter (D50) of the abrasive grains on the known cutting line, the diameter (D50) of the abrasive grains on the cutting line of the present invention is lower, and the density of the abrasive grains is large, as can be known through experiments, the diameter of the abrasive grains ( D50) and the density of abrasive particles in the above range, can maintain a good cutting force, and can effectively improve the surface roughness, flatness and curvature (BOW) of the wafer, and have good warpage (WARP) , and reduce the probability of fragmentation and internal cracking.

FIG. 1 is a schematic diagram of an ingot cutting tool according to an embodiment of the present invention. Please refer to FIG. 1 , the ingot cutting tool 10 of the present embodiment includes two rollers 30 and multiple rows of cutting lines 20 wound on the two rollers 30 , and these rows of cutting lines 20 are arranged in parallel and at intervals. The crystal ingot 50 is arranged on the fixed seat 40, and the fixed seat 40 can approach or move away from (up and down) toward the direction of the roller 30, so that the crystal ingot 50 can be brought downward by the fixed seat 40, and pass through these rows of cutting lines 20, To cut out a plurality of wafers; it is worth noting that the selection of abrasive particles 24 can be adjusted depending on the material of the wafer to be cut, and abrasive particles 24 of different hardness are used, such as diamond or other high-hardness materials such as sapphire Or boron carbide, the present invention is not limited thereto.

FIG. 2 is a partially enlarged schematic diagram of a cutting line of the ingot cutting tool in FIG. 1 . It should be noted that Fig. 2 is only a schematic representation, and the size, shape and relative position are not in real scale, and the material of the abrasive particles 24 is diamond particles 24' as an example, but the present invention is not limited thereto. Please refer to FIG. 2 , the cutting wire 20 includes a wire body 22 and a plurality of diamond particles 24', and these diamond particles 24' are arranged on the wire body 22. In this embodiment, the wire diameter of the wire body 22 is about 120 microns, the diameter D (D50) of each diamond particle 24' is between 5 microns and 30 microns, and the density of these diamond particles 24' is between 1000 /mm² to 5000 grains/mm².

The abrasive particles on the conventional cutting wire, such as diamond particles, have a diameter (D50) greater than 30 microns, such as 30 microns to 40 microns, and the density of the diamond particles is about 300 grains/mm2 to 800 grains/mm2. Compared with the diameter (D50) of the diamond particles on the known cutting line, the abrasive particles on the cutting line 20 of the present embodiment, such as the diameter D (D50) of the diamond particles 24' is lower, and the density of the diamond particles 24' Come big.

The following table 1 is a comparison table between the conventional cutting line and the cutting line 20 of this case and the silicon carbide wafer cut by it. Among them, the abrasive grains on the cutting line of the conventional and this case are diamond particles as an example, but in this case The invention is not limited thereto. Known cutting line Cutting line in this case line spacing 606 microns 586 microns Slicing yield 90.1% 100% Average (micron) Standard Deviation STD Average (micron) Standard Deviation STD Wafer Center Thickness 418.8 1.83 420.17 1.8 Total Wafer Thickness Variation (TTV) 9.94 4.09 8.62 1.04 Wafer Bow (Bow) 9.87 4.33 6.43 4.15 Wafer warpage (Warp) 24.72 6.96 25.15 6.03 Table I

It can be seen from Table 1 that due to the larger diameter (D50) of diamond particles in conventional cutting lines, the overall cutting line is relatively thick. If a wafer with a thickness of 420 microns is to be cut, the distance between two adjacent rows of cutting lines is 606 mm. Micron. The diameter D (D50) of the diamond particles 24 in this case is relatively small, and the overall cutting line 20 is relatively thin. If a wafer with a thickness of 420 micrometers is to be cut, the distance between two adjacent rows of cutting lines 20 is only 586 micrometers. In other words, under a certain crystal anchor size, more cutting lines 20 of this case can be accommodated, and the crystal ingot 50 can be cut into more wafers, and it can be seen from the data in Table 1 that the diameter of the diamond particles 24' of this case D (D50) is smaller than the conventional one, the overall cutting line 20 is thinner than the conventional one, and the line spacing is also smaller than the conventional one, but the center thickness of the wafer after dicing is similar to the conventional one, so according to the design of this case, Wafers with substantially the same thickness or similar to conventional thicknesses can be cut, because the cutting loss (Kerf-loss) is small, and the yield rate is improved, and the goal of saving costs and cutting more wafers can be achieved.

In addition, it can be known from experiments that when the diameter D (D50) of the diamond particle 24' and the density of the diamond particle 24' in this case are in the above-mentioned range, even for the crystal ingot 50 with Mohs hardness greater than or equal to 9, such as SiC material, it can still be used. It has good cutting force, and can effectively improve the surface roughness of the wafer, and the flatness and geometric shape are also good, and reduce the probability of fragmentation and internal cracking, and the slicing yield can be increased to 100%.

In addition, using the dicing line 20 of this case, the wafer after dicing has a lower total thickness variation (Total Thickness Variation, TTV), and the numerical value of the total thickness variation (TTV) has been improved, and the wafer is relatively flat and undisturbed. There may be deterioration. In addition, the curvature (Bow) also has better performance, and the warp (Warp) is in good condition.

Furthermore, the smaller the diameter D ( D50 ) of the abrasive grains 24 of the present invention, the greater the density of the abrasive grains 24 required. For example, in one embodiment, the diameter D of each abrasive grain 24 is between 10 microns and 30 microns, and the density of these abrasive grains 24 is between 1000 grains/square millimeter and 3000 grains/square millimeter between.

In one embodiment, the diameter D of each abrasive particle 24 is between 5 microns and 25 microns, between 5 microns and 30 microns, between 10 microns and 30 microns, between 15 microns and 30 microns, or between 20 microns and 30 microns , and the density of these abrasive particles 24 is between 1200 grains/mm2 and 5000 grains/mm2, between 1000 grains/mm2 and 3500 grains/mm2, and between 1000 grains/mm2 Between 2500 grains/mm2 or between 1000 grains/mm2 and 1800 grains/mm2, wherein the material of the abrasive grains 24 is preferably diamond grains, but the present invention is not limited thereto.

In one embodiment, the diameter D of each abrasive grain 24 is between 5 microns and 25 microns, and the density of these abrasive grains 24 is between 1200 grains/mm2 and 5000 grains/mm2.

In one embodiment, the diameter D of each abrasive grain 24 is between 5 microns and 30 microns, and the density of these abrasive grains 24 is between 1000 grains/mm2 and 5000 grains/mm2.

In one embodiment, the diameter D of each abrasive grain 24 is between 10 microns and 30 microns, and the density of the abrasive grains 24 is between 1000 grains/mm2 and 3500 grains/mm2.

In one embodiment, the diameter D of each abrasive particle 24 is between 15 microns and 30 microns, and the density of these abrasive particles 24 is between 1000 grains/mm2 and 2500 grains/mm2.

In one embodiment, the diameter D of each abrasive grain 24 is between 20 microns and 30 microns, and the density of these abrasive grains 24 is between 1000 grains/mm2 and 1800 grains/mm2.

According to tests, the relationship between the diameter D ( D50 ) and the density of the abrasive grains 24 can have a good cutting force, effectively improve the surface roughness of the wafer, and reduce the probability of fragmentation and internal cracking.

FIG. 3 is a graph showing the relationship between slice number and surface roughness of an ingot cut by the ingot cutting tool in FIG. 1 . It should be noted that, in Fig. 3, the dotted line indicates that the crystal ingot cutting tool adopts a known cutting line to cut the crystal ingot, and the number of the cut wafer is related to the surface roughness, and the solid line indicates that the crystal ingot in this case The cutting line 20 of the cutting tool 10 is used to cut the crystal ingot 50 , and the number of the cut wafers is related to the surface roughness.

Please refer to FIG. 3 , the surface roughness of the wafers cut out by cutting the crystal ingot 50 with the cutting line 20 of this case is obviously lower than that of the wafers cut out by cutting the crystal ingot with the conventional cutting line, For example, using a known cutting line to cut the ingot, as shown by the dotted line, the surface roughness of the wafer will even be greater than 2.5 μm, or even more than 4 μm, but cutting the crystal anchor with the cutting line of the present invention, as realized It is shown that the surface roughness of the wafer can be less than 2.5 μm, even to 0.5 μm, so that the wafer has good quality.

In summary, the diameter (D50) of each abrasive grain of the cutting wire of the present invention is between 5 microns and 30 microns, and the density of these abrasive grains is between 1000 grains/square millimeter and 5000 grains/square millimeter between. Compared with the diameter (D50) of the abrasive grains on the known cutting line, the diameter (D50) of the abrasive grains on the cutting line of the present invention is lower, and the density of the abrasive grains is large, as can be known through experiments, the diameter of the abrasive grains ( D50) and the density of abrasive particles in the above range, can maintain a good cutting force, and can effectively improve the surface roughness of the wafer, and the flatness and geometric shape are also good, reducing the probability of fragmentation and internal cracking, slicing The yield rate can be increased to 100%, wherein the abrasive particles are preferably diamond particles, but the invention is not limited thereto.

D: diameter 10: Ingot Cutting Tool 20: cutting line 22: line body 24: Abrasive particles 24': diamond particles 30: Roller 40: Fixed seat 50: crystal anchor

FIG. 1 is a schematic diagram of an ingot cutting tool according to an embodiment of the present invention. FIG. 2 is a partially enlarged schematic diagram of a cutting line of the ingot cutting tool in FIG. 1 . FIG. 3 is a graph showing the relationship between slice number and surface roughness of an ingot cut by the ingot cutting tool in FIG. 1 .

D: diameter 20: cutting line 22: line body 24: Abrasive particles 24': diamond particles

Claims (4)

A cutting wire, suitable for cutting crystal ingots, comprising: a wire body: and a plurality of abrasive grains disposed on the wire body, wherein each of the abrasive grains has a diameter (D50) between 5 microns and 30 microns, and the The abrasive grains have a density between 1000 grains/mm2 and 5000 grains/mm2, each of the abrasive grains has a diameter between 20 microns and 30 microns, and the abrasive grains have a density of 1000 Between grains/mm2 and 1800 grains/mm2. The cutting wire according to claim 1, wherein each of the abrasive grains is a diamond grain. A crystal ingot cutting tool, comprising: a plurality of rows of cutting lines arranged in parallel and at intervals, the cutting lines comprising: a line body: and a plurality of abrasive grains disposed on the line body, wherein the diameter of each of the abrasive grains (D50) Between 5 microns and 30 microns, and the density of the abrasive grains is between 1000 grains/mm2 and 5000 grains/mm2, wherein the diameter of each abrasive grain is between 20 microns and 30 microns Between, and the density of these abrasive particles is between 1000 grains/mm2 and 1800 grains/mm2. The ingot cutting tool as claimed in claim 3, wherein each of the abrasive grains is a diamond grain.

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