JPH0818255B2 - Ultra-thin blade grindstone - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrathin blade grindstone used for ultraprecision machining of semiconductor elements and the like.

"Prior Art" Fig. 3 shows an example of an ultra-thin blade grindstone of this type.

This ultrathin blade grindstone (electroformed thin blade grindstone) 1 has a thickness of 15 μm formed by dispersing superabrasive grains such as diamond and CBN in a metal plating phase made of Ni, Co or their alloys.
It is a ring-shaped thin plate with a thickness of several hundred μm, and particularly for cutting and dividing (silicon dicing) for cutting chips from a wafer, an extremely thin one with a thickness of 50 μm or less is used.

The grindstone 1 is sandwiched between the pair of mounting flanges 2 and 2 on both side surfaces and fixed to the grindstone shaft 4 with the nut 3 for use.

"Problems to be solved by the invention" By the way, in the above-mentioned ultra-thin blade grindstone, ultra LS
When used for cutting and dividing I and CCD (charge coupled device),
There was a problem that the life of the grindstone was remarkably shortened compared to the case of cutting and dividing IC with low integration, and it could not be used.

When the reason why such a noticeable difference in life occurs even when the work material is the same silicon, it was found that the cause was the grinding fluid used during cutting. Ultra-pure water is used as the grinding fluid for normal IC cutting, whereas in the case of VLSI and CCD cutting, carbon dioxide is dissolved in ultra-pure water to a PH4 level. Has been. Therefore, the interaction between the corrosion of the grinding fluid and the friction of the work material,
That is, Ni that constitutes the metal plating phase of the grindstone is abraded at a relatively large speed due to fretting corrosion, and the life of the grindstone is significantly shortened. (Note that VLSI as described above
The reason why an acidic grinding fluid is used for cutting CCDs and CCDs is to increase the electric conductivity of the grinding fluid and prevent a discharge phenomenon due to frictional electrification between the grindstone and the wafer. With the degree of integration of an IC, even if this kind of discharge occurs, the element will not be destroyed.
When the degree of integration is increased as in LSI and CCD, the element pattern is destroyed even by a weak discharge. Therefore, the present inventors have studied the above-mentioned problem of fretting corrosion in detail and have obtained the following findings.

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

In particular, the effect becomes remarkable when any of Ni-based alloy, Co-based alloy, and Ni-Co-based alloy is used as the amorphous alloy.

When one or more elements such as P, B, Mo, W, Re are added to the amorphous alloy, the self-passivation action of the plating phase is promoted and a passivation film having a strong regenerative power is formed on the surface. The corrosion resistance can be further improved.

"Means for Solving Problems" The present invention has been made based on the above findings, and is characterized in that the metal plating phase of the grindstone is composed of an amorphous alloy.

The amorphous alloy is preferably Ni-based, Co-based or Ni-Co-based.

Further, the amorphous alloy may contain one or more elements selected from P, B, Mo, W and Re, and in that case, the content is preferably 1 to 30 wt%. If it is less than 1 wt%, the above-mentioned self-passivation action becomes insufficient, and if it is more than 30 wt%, the strength of the plating phase decreases.

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

First, the outline of the grindstone manufacturing apparatus will be described with reference to FIG. 1. Reference numeral 10 is a plating tank in which a stirrer is arranged. In the plating tank 10, a non-conductive pedestal 11 is horizontally arranged. ing. 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 while leaving a portion of the prototype shape of the grindstone to be manufactured. Further, an anode plate 13 is arranged above the plane substrate 12 in parallel therewith.

When electrolytic plating is performed by this apparatus, the flat substrate 12 is connected to the cathode of the power source and the anode plate 13 is connected to the anode of the power source, and the plating solution M is energized while being stirred. Then, after the abrasive grain layer 14 having a predetermined thickness is deposited on the flat substrate 12, the abrasive grain layer 14 is separated from the flat substrate 12 and washed and shaped to obtain an annular grindstone. Further, when electroless plating is performed, it is not necessary to energize, so the anode plate 13 is removed, and otherwise a grindstone is prepared by the same operation as described above. In the following 7 kinds of grindstones, Examples 1 to 6 all have an amorphous metal plating phase, and Comparative Example has a crystalline metal. In addition, all the shapes of the grindstone, outer diameter 50.2mmφ, inner diameter 40.0mmφ,
The thickness was 15 μm and the diamond abrasive grain size was 5 μm.

(Example 1) electroplating solution composition (abrasive omitted, hereinafter the _{same) NiSO 4 · 6H 2 O:} 150g / NiCl 2 · 6H 2 O: 45g / NiCO 3: 30g / H 3 PO 4: 50g / H 3 PO ₃ : 40g / PH1 Electrolytic plating conditions Liquid temperature: 70 ℃ Cathode current density: 5A / dm ² Grinding wheel composition Metal plating phase P: 10wt%, Ni content in balance Ni: 31vol% (Example 2) Electroless plating Liquid composition NiCl ₂・ 6H ₂ O: 30g / Ethylenediamine: 60g / NaOH: 40g / NaF: 3g / NaBH ₄ : 0.5g / PbCl ₂ : 0.06g / Electroless plating conditions Liquid temperature: 50 ℃ Grindstone composition Plating phase B : 7 wt%, the balance Ni abrasive content: 38 vol% (example 3) electroless plating solution composition _{NiSO 4: 0.03mol / Na 2 WO} 4: 0.1mol / NaH 2 PO 2: 0.1mol / citric acid Na: 0.1 mol / PH8 Electroless plating conditions Liquid temperature: 90 ° C Grinding wheel composition Plating phase W: 10wt%, P: 6wt%, balance Ni abrasive grain content: 35vol% (Example 4) Electroless plating solution composition CoSO ₄ : 0.05 mol / NaH ₂ PO ₂ : 0.2mol / citrate Na: 0.2mol / (NH ₄ ) ₂ SO ₄ : 0.5mol / PH9 electroless plating conditions Liquid temperature: 90 ℃ Grinding stone composition Plating phase P: 4.5 wt%, balance Co abrasive grain content: 37 vol% (Example 5) Electrolytic plating solution composition Molybdic acid: 0.05 mol / NiSO ₄ : 0.22 mol / Na tartrate: 0.27 mol / PH 10.5 Electrolytic plating conditions Liquid temperature: 30 ° C. Cathode current density: 10 A / dm ² Grinding stone composition Plating phase composition Mo: 20 wt%, balance Ni abrasive grain content: 27 vol% (Example 6) Electrolytic plating composition Na perrhenate: 0.025mol / NiSO ₄ : 0.1mol / Na citrate: 0.17mol / PH8.0 Electroplating conditions Liquid temperature: 50 ℃ Cathode current density: 3A / dm ² Grinding wheel composition Plating phase Re: 22wt%, balance Ni abrasive grains included Amount: 29vol% (Comparative example) Electrolytic plating composition NiSO ₄ : 250g / NiCl ₂ : 30g / H ₃ BO ₃ : 30g / Small amount of brightener PH4.0 Electroplating conditions Liquid temperature: 50 ℃ Cathode current density: 3A / dm ² Composition of Grinding Wheel Plating Phase Crystalline Ni Abrasive Grain Content: 32 vol% Next, a wafer cutting test was performed under the following conditions using the above 7 kinds of ultra-thin blade grindstones.

Rotational speed: 30,000 rpm Feed rate 100 mm / sec. Depth of cut: 100 μm Depth: 200 μm Work material: 5 inch φ Silicon wafer Grinding fluid: Carbon dioxide dissolved ion exchange water (PH4) Cutting distance: 10,000 The results are shown in the table below Shown in.

As shown in the above table, the grindstones of Examples 1 to 6 were able to significantly reduce the fretting corrosion as compared with the grindstone of the comparative example.

In the above examples, the Ni-based or Co-based alloy constitutes the amorphous plating phase, but the present invention is not limited to these, and Ni-Co-based alloy, or other metal as the main component. The alloy may be

Further, in each of the above examples, in order to simultaneously satisfy the purpose of making the plating phase amorphous, and the purpose of promoting the self-passivation action of the plating phase, one of P, B, Mo, W, and Re. Although the compound was added to the plating solution to form an amorphous plating phase, it is possible to obtain an amorphous alloy by adding an element other than these.

Further, 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 the hub 20 and the abrasive grain layer 21 made of aluminum or the like are integrally formed as shown in FIG. Good.

"Effects of the Invention" As described above, the ultra-thin blade grindstone of the present invention has a metal plating phase composed of an amorphous alloy, and therefore has significantly higher corrosion resistance than a conventional grindstone in which the plating phase is crystalline, Even when an acidic grinding fluid in which carbon dioxide gas is dissolved is used, abrasion can be prevented and a long life can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a plating apparatus used for manufacturing an ultrathin blade grindstone of an embodiment of the present invention, FIG. 2 is a sectional view showing a grindstone of another embodiment, and FIG. 3 is a conventional ultrathin blade grindstone. It is sectional drawing which shows an example. 10 …… plating tank, 14 …… abrasive grain layer, 20 …… aluminum hub, 21 …… abrasive grain layer.

Claims (3)

[Claims] 1. An ultrathin blade grindstone having an abrasive grain layer in which superabrasive grains are dispersed in a metal plating phase, wherein the metal plating phase is made of an amorphous alloy. 2. The amorphous alloy is Ni-based, Co-based or Ni-
The ultrathin blade grindstone according to claim 1, which is one of Co bases. 3. The pole according to claim 1 or 2, wherein the amorphous alloy contains one or more elements selected from P, B, Mo, W and Re. Thin blade whetstone.