JP2785376B2 - Ultra-thin blade and its manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultra-thin blade grindstone used for ultra-precision machining of semiconductor elements and the like, and a method of manufacturing the same.

"Prior Art" FIG. 3 shows an example of this kind of ultra-thin blade whetstone.

This ultra-thin blade (electroformed thin blade) 1 has a thickness of 15 μm or more formed by dispersing superabrasive grains such as diamond and CBN in a metal plating phase made of Ni, Co or an alloy thereof.
It is a ring-shaped thin plate having a thickness of several hundreds of μm. In particular, for cutting and dividing (silicon dicing) for cutting chips from a wafer, an extremely thin one having a thickness of 50 μm or less is used.

The whetstone 1 is sandwiched on both sides by a pair of mounting flanges 2 and fixed to a whetstone shaft 4 with a nut 3 for use.

[Problems to be Solved by the Invention] By the way, in the ultra-thin blades described above, the super LS
When used for cutting division of I or CCD (charge coupled device),
There is a problem that the life of the grindstone is remarkably shortened as compared with the case of cutting and dividing an IC having a low degree of integration, so that it cannot be used.

When the reason why such a remarkable difference in service life occurs was examined even though the work material was the same silicon, it was found that the cause was the grinding fluid used at the time of cutting. While ultra-pure water is used as a grinding fluid for cutting ordinary ICs, ultra-pure water is used to remove electrostatic discharge phenomena due to frictional charging when cutting ultra-LSIs and CCDs. Grinding fluid is used by dissolving to about PH5. Therefore, the interaction between the corrosion by the grinding fluid and the friction of the work material, that is, the abrasion corrosion, constitutes the metal plating phase of the grinding wheel
Ni wears at a relatively high rate, which significantly shortens the wheel life.

Then, the present inventors studied in detail the problem of fretting corrosion and disclosed the following idea in Japanese Patent Application No. 62-82056.

By configuring the metal plating phase of the grinding wheel with an amorphous alloy (including an amorphous alloy), the corrosion resistance of the plating phase is improved, and fretting corrosion can be prevented.

The effect of using a Ni-based alloy, a Co-based alloy, or a Ni-Co-based alloy as the amorphous alloy becomes remarkable.

When elements such as P, B, Mo, Wo, and Re are added to the amorphous alloy, the self-passivation effect of the plating phase is promoted, and a passive film having a strong regenerative power is formed on the surface, and the corrosion resistance is further improved. improves.

However, when these amorphous alloys are used as a binder, the binder lacks toughness, and although it has good cutting characteristics in light-load cutting applications, a grinding wheel is not used in heavy-load cutting applications such as deep cutting or high-speed cutting. It was found that there was a problem because it could not withstand the load and was damaged.

The present invention has been made by further advancing the above findings, and has as its object to further enhance the effect of preventing fretting corrosion and breakage resistance in an ultra-thin blade.

[Means for Solving the Problems] The ultra-thin blade wheel according to the present invention is characterized in that the electrometal plating phase constituting the abrasive layer is formed of a crystalline Ni-based alloy containing 0.5 to 3 wt% of P. .

If the content of P is less than 0.5 wt%, a sufficient self-passivation effect cannot be obtained, and if it is more than 3 wt%, the strength and toughness of the electrometal plating phase decrease. On the other hand, if it exceeds 3 wt%, the internal stress of the electrometallic plating phase increases significantly, and the ultrathin blade grindstone is bent or deformed.

On the other hand, the method for producing an ultra-thin blade according to the present invention comprises: Ni-sulfamic acid: 250 to 700 g / l, hypophosphite or / and / or hypophosphorous acid: 0.05 to 3 g / l, boric acid: 10 to 50 g / l l, using an electroplating solution containing a small amount of a stress reducing agent and a small amount of a pit preventing agent, dispersing superabrasive grains in the plating solution to precipitate an abrasive layer, and forming an electrometal plating layer of the abrasive layer. As 0.5
It is characterized in that a crystalline Ni-based alloy containing up to 3 wt% of P is obtained.

If the amount of Ni sulfamate is less than 250 g / l, the allowable maximum current density decreases, and if it is more than 700 g / l, the effect corresponding to the increase in addition cannot be obtained, so the concentration of Ni sulfamate is set in the above range. If the amount of hypophosphite or hypophosphorous acid is out of the range of 0.05 to 3 g / l, the content of P in the metal plating phase does not become the above-mentioned content. 10 more boric acids
If it is less than g / l, the effect as a PH buffer will be insufficient, and if it is more than 50 g / l, harmfulness to the apparatus due to the precipitation of boric acid will occur.

As the stress reducing agent, saccharin sodium, sodium naphthalene trisulfonate and the like can be used, and the addition amount thereof is preferably 1 to 10 g / l. A nonionic surfactant or an anionic surfactant is used as a pit preventing agent, and the amount of addition is 0.1 to 5 g / l. Suitable pit inhibitors include sodium lauryl sulfate.

"Examples" Next, the effects of the present invention will be demonstrated with examples.

First, an outline of a grindstone manufacturing apparatus will be described with reference to FIG. 1. Reference numeral 10 denotes a plating tank provided with a stirrer, in which a non-conductive base 11 is horizontally disposed. Have been. A flat substrate 12 made of stainless steel is placed on the pedestal 11, and masking is performed on the upper surface of the flat substrate 12 except for a portion forming the original shape of the grindstone to be manufactured. Further, above the flat substrate 12, an anode plate 13 is arranged in parallel with the flat substrate 12.

When electroplating is performed by this apparatus, the flat substrate 12 is connected to a cathode of a power supply, and the anode plate 13 is connected to an anode of a power supply. After the abrasive layer 14 having a predetermined thickness is deposited on the planar substrate 12, the abrasive layer is separated from the planar substrate 12, and is washed and shaped to obtain an annular grindstone.

In the following seven types of grinding stones, Examples 1 to 6 all contain P in the metal plating phase, and Comparative Example 1 does not contain P.

In addition, the shape of each whetstone is 50.4 mmφ in outer diameter and 4 in inner diameter.
0.0 mmφ, 25 μm in thickness, diamond abrasive grain size # 2500 (about 4 to 6 μm), and the abrasive grain content was 30 vol%.

(Example 1) Composition of electroplating solution (abrasive grains are omitted, the same applies hereinafter) Ni sulfamate: 350 g / l, sodium hypophosphite: 2.0 g / l, boric acid: 30 g / l, stress reducing agent (saccharin sodium) : 3g / l, pit inhibitor (Pitless S, manufactured by Nippon Chemical Industry Co., Ltd.): 3ml / l, electroplating conditions Liquid temperature: 50 ° C Cathode current density: 3A / dm ² Composition of grinding wheel Metal plating phase P: 2.0 wt%, balance Ni and unavoidable impurities (Examples 2 to 6) In the plating solution shown in Example 1, the amount of sodium hypophosphite was appropriately changed in the range of 0.05 to 3 g / l, and Table 1 was obtained. A grindstone having the P content shown in Table 1 was prepared.

(Comparative Example 1) Electroplating solution composition Ni sulfate 350g / l, Ni chloride 30g / l, boric acid: 30g / l, brightener small amount, PH4.0 Electroplating conditions Liquid temperature: 50 ° C Cathode current density: 3A / dm ² Grinding wheel composition Plating phase: Ni and unavoidable impurities Next, a wafer cutting test was performed using the above seven kinds of ultra-thin blades under the following conditions.

Number of revolutions: 30,000 rpm, feed rate: 100 mm / sec Cutting amount: 250 μm, protrusion amount: 50 μm Work material: 5 inch φ silicon wafer Grinding fluid: Carbon dioxide dissolved ion exchange water (PH5) Number of cuts: 20,000 It is shown in Table 1. In addition, the grindstone friction amount in the following table is a value in the radial direction of the grindstone.

As shown in the above table, in the grindstones of Examples 1 to 6, abrasion corrosion was significantly reduced as compared with the grindstone of Comparative Example 1.

Further, in the plating solution shown in Example 1, hypophosphorous acid was used.
The amount of Na was increased, and whetstones having a P content of 3.5 wt%, 5 wt%, and 8 wt% were prepared, respectively, to obtain whetstones of Comparative Examples 2, 3, and 4.
Then, using the grindstones of Examples 1 and 6 and Comparative Examples 2, 3, and 4, the cutting amount in the wafer cutting test was 400 μm.
A heavy-load deep-cut cutting test was performed, which was changed to.

As a result, in the cutting test of each grindstone 5 times, the number of times of breakage of each grindstone was as follows: Example 1: 0 times, Example 6: 1 time, Comparative example 2: 3 times, Comparative example 3: 4 times, Comparative example 4: 5 times, and it was found that each example had excellent breakage resistance. Further, in the grindstones of Comparative Examples 2, 3, and 4, a large curvature was observed in the grindstone as the P content increased. As a result of X-ray diffraction analysis, each of the grindstones of Examples 1 to 6 and Comparative Examples 1 to 3 was crystalline, and the grindstone of Comparative Example 4 was amorphous.

In addition, the ultra-thin blade grindstone of the present invention is not limited to the disk type as described above, and has a shape in which a hub 20 made of aluminum or the like and an abrasive phase 21 are integrally formed as shown in FIG. Is also good.

"Effects of the Invention" As described above, the ultra-thin blade wheel of the present invention is formed by forming the electrometal plating phase constituting the abrasive layer from a crystalline Ni-based alloy containing 0.5 to 3 wt% of P, The corrosion resistance of the abrasive layer is remarkably enhanced, and even when an acidic grinding liquid in which carbon dioxide gas is dissolved is used, abrasion corrosion can be prevented, a long life can be obtained, and the breakage resistance of the grinding wheel can be improved.

Further, according to the method for producing an ultra-thin blade wheel according to the present invention, it is possible to easily produce an ultra-thin blade wheel satisfying the above composition.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plating apparatus used for manufacturing an ultra-thin blade grindstone of an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a grindstone of another embodiment, and FIG. 3 is a conventional ultrathin blade grindstone. FIG. 3 is a cross-sectional view showing one example. 10 ... Plating tank, 14 ... Abrasive layer 20 ... Aluminum hub, 21 ... Abrasive layer.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-251171 (JP, A) JP-A-59-59352 (JP, A) JP-A-59-124574 (JP, A) JP-A-63-251 156663 (JP, A)

Claims (2)

(57) [Claims] An ultra-thin blade having an abrasive layer in which superabrasive grains are dispersed in an electrometal plating phase, wherein the electrometal plating phase is a crystalline Ni-based alloy containing 0.5 to 3 wt% of P. An ultra-thin blade whetstone. 2. Ni sulfamate: 250 to 700 g / l, hypophosphite or / and / or hypophosphorous acid: 0.05 to 3 g / l, boric acid: 10
~ 50 g / l, using an electroplating solution containing a small amount of a stress reducing agent and a small amount of a pit inhibitor, dispersing superabrasive grains in the electroplating solution to precipitate an abrasive layer, Crystalline Ni containing 0.5-3wt% P as electrometal plating phase
A method for producing an ultra-thin blade whetstone, wherein a base alloy is obtained.