JPH10138120A - Jig for dressing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the dressing of the grinding cloth with excellent reproducibility, and to easily remove the grinding material to be left in the grinding cloth by forming a plurality of tapered projections on an outer surface of a plate-shaped body consisting of one kind of ceramics, cermet, and cemented carbide. SOLUTION: In a jig 21 for dressing, a plurality of tapered projections 23 are provided on an outer surface of a circular plate-shaped body 22 consisting of one kind of ceramics, cermet, and cemented carbide. The height of the projections 23 is about 0.1-5.0mm and the pitch width is about 0.2-5.0mm so as to perform the dressing of the grinding cloth consisting of the resin such as foamed urethane resin with excellent reproductivity. The tip of the projections 23 is preferably and basically pointed to improve the dressing effect, but a flat part may be present on a tip so far as the dressing effect is not degraded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dressing jig used for dressing a polishing cloth provided on a polishing plate of a polishing device such as a polishing device or a lapping device.

[0002]

2. Description of the Related Art
2. Description of the Related Art A polishing apparatus such as a polishing apparatus or a lap apparatus is used to polish a surface of a workpiece or to obtain a smooth mirror surface.

For example, in the manufacturing process of a semiconductor device,
With the increase in the density and integration of SI, multilayering of wirings has progressed. In order to flatten the surface of the laminated film due to the repetition of film formation, etching, and exposure, CMP (CHEMICAL &
A MECHANICAL POLISH device is used.

FIG. 3 shows a schematic view of a CMP apparatus.
A holding plate 12 for holding a semiconductor wafer 13 as a workpiece, and a polishing plate 1 arranged opposite to the holding plate 12
The polishing disc 1 is made of a metal disc 2
A polishing cloth 3 made of a resin film such as a foamed urethane resin having a film thickness of about 5 mm was adhered to the surface of the substrate through an adhesive seal (not shown). Then, after attaching the semiconductor wafer 13 to the holding plate 12 with wax, the semiconductor wafer 13 is pressed against the polishing plate 1, and a polishing liquid (not shown) for mixing an abrasive between the polishing plate 1 and the semiconductor wafer 13. ) Is supplied while the polishing plate 1 alone is rotated, or the holding plate 1
The surface of the laminated film laminated on the semiconductor wafer 13 is planarized by flattening the surface of the laminated film laminated on the semiconductor wafer 13 by relatively rotating the polishing plate 1 and the polishing plate 1.

Further, particularly when the workpiece is a semiconductor wafer 13, the polishing allowance is very small, less than 1 μm, and the polishing must be performed uniformly. Brushing was essential.

Therefore, a diamond grindstone in which diamond abrasive grains are fixed to the surface of a plate-like body made of metal such as stainless steel with nickel (Ni) has been used for dressing (grinding) the polishing cloth of the polishing machine. The grindstone is pressed against the polishing cloth 3 of the polishing disc 1 to move the grindstone 31 along the surface of the polishing cloth 3 while rotating both the grindstone and the polishing disc 1 relatively. By doing so, the polishing cloth 3 is sharpened (haired) and the abrasive remaining on the polishing cloth 3 is removed.

However, since the grain size of the diamond abrasive grains fixed to the diamond grindstone is not uniform, even if the polishing cloth 3 is dressed with this diamond grindstone, the reproducibility of the surface state of the polishing cloth 3 is not so large. Not good
Even if the workpiece is polished under the same conditions, it cannot be polished uniformly, and there is a problem that the variation is large.

Further, in the case of a diamond grindstone, since the diamond abrasive grains are likely to fall off and remain on the polishing pad 3, if the workpiece is polished while the diamond abrasive grains are retained, the diamond abrasive grains may be processed. There is a problem that the object is damaged, and when the object to be processed is the semiconductor wafer 13, there is a possibility that a fatal defect such as disconnection may be caused by the damage.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a method for dressing a polishing cloth provided on a polishing plate of a polishing apparatus, in which a plate made of ceramic, cermet, cemented carbide or the like is used. A dressing jig is constituted by providing a large number of tapered projections on the surface.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a perspective view showing a dressing jig 21 according to the present invention, in which a plurality of tapered projections 23 are formed on the outer surface of a circular plate 22 made of one of ceramics, cermet, and cemented carbide. The projection 23 has a shape such as a conical shape as shown in FIG. 2A or a pyramid shape such as a quadrangular pyramid as shown in FIG. The projection 23 has a tapered shape.

In order to sharpen a polishing cloth made of a resin such as urethane foam resin with good reproducibility, the height t of the projections 23 is set to 0.1 to 5.0 mm and the pitch width W is set to 0.1 to 5.0 mm.
2 to 5.0 mm.

This is because if the height t of the protrusion 23 is higher than 5.0 mm, the strength is insufficient, and the tip of the protrusion 23 is easily damaged at the time of dressing. The height t of the protrusion 23 is smaller than 0.1 mm. This is because if the size becomes smaller, a sharpening effect cannot be obtained so much that the polishing cloth cannot be sharpened with good reproducibility. Also, if the pitch width W of the projections 23 is smaller than 0.2 mm, the sharpening effect is hardly obtained due to the relationship with the height t of the projections 23, and conversely, 5.0 m.
If it is larger than m, the distance between the tips of the projections 23 is too large, so that it does not take much time to uniformly sharpen the surface of the polishing pad, and the workability deteriorates.

In order to enhance the sharpening effect, projections 2
The tip of the tip 3 is preferably basically pointed, but if the sharpening effect is not reduced, a flat surface 23a
In this case, the maximum length R of the flat surface 23a
Is desirably 0.2 mm or less.

The dressing jig 21 shown in FIG.
In the above, the example of the circular plate-shaped body 22 is shown, but the dressing jig 21 is shaped like a polygon such as a square or a hexagon, an ellipse, or a decoration such as a star. You may give it. Further, it is not always necessary to arrange all the projections 23 at the same pitch, and the pitch intervals of the projections 23 may be different within a range of 0.2 to 5.0 mm if they are slight. The peripheral part may be made sparse, or conversely, the central part may be made sparse and the peripheral part may be made dense.

The dressing jig 21 needs to be formed of a ceramic, cermet, or cemented carbide having high toughness, high hardness, and high strength as described above. As the ceramic, those mainly composed of alumina, zirconia, silicon nitride and silicon carbide are preferable.

For example, alumina (Al ₂ O ₃ ) is 99 to 99.9% by weight, and silica (SiO ₂ ), magnesia (MgO) and calcia (CaO) are used as sintering aids. At a temperature of 1500 to 1800 ° C. in an air atmosphere or a vacuum atmosphere.
And alumina (A)
(I ₂ O ₃ ) 93-99% by weight, and yttria (Y ₂
O ₃ ), magnesia (MgO), calcia (CaO),
1 to 7% by weight of zirconia stabilized or partially stabilized with a stabilizer such as ceria (CeO ₂ ) is added to form a plate having a desired shape, and then, in an air atmosphere or a hydrogen atmosphere. 1500 to 170 in a nitrogen atmosphere
Baking at a temperature of 0 ° C. for about 1 to several hours, or adding 40 to 20% by weight of titanium carbide (TiC) to 60 to 80% by weight of alumina (Al ₂ O ₃ ) to form a desired shape After being formed into a plate-like body, it is heated at a temperature of 1300 to 2000 ° C. for 1 to 5 in an air atmosphere or a reduced pressure atmosphere.
What was baked for about an hour can be used.

Examples of the zirconia ceramics include zirconia (ZrO ₂ ) partially stabilized with _{3 to} 9 mol% yttria (Y ₂ O ₃ ), and 16 to 26 mol%.
% Of zirconia (ZrO ₂ ) partially stabilized with magnesia (MgO), 8-12 mol% of zirconia (ZrO ₂ ) partially stabilized with calcia (CaO), and 8-16 mol% of ceria (CeO ₂ ). After the stabilized zirconia (ZrO ₂ ) is formed into a plate having a desired shape, it is set at 1400 to 1600 ° C. in an air atmosphere.
What is fired at a temperature of about 1 to several hours may be used.

Further, as silicon carbide-based ceramics,
Based on 90 to 99% by weight of silicon carbide (SiC), boron (B) and carbon (C) or alumina (A)
l ₂ O ₃ ) and yttria (Y ₂ O ₃ ) in total of 10 to 1
After adding the weight%, it is shaped into a plate having a desired shape, and then heated to 1900 to 2100 ° C. in an inert gas atmosphere.
At a temperature of about 1 to 3 hours.

Further, as silicon nitride-based ceramics, silicon nitride (Si ₃ N ₄ ) is 96 to 98% by weight,
After adding a total of 2 to 4% by weight of alumina (Al ₂ O ₃ ) and yttria (Y ₂ O ₃ ) as a sintering aid, the mixture is formed into a plate having a desired shape, and is then placed in a nitrogen atmosphere. What is fired at a temperature of 1800 to 1900 ° C. for about 1 to several hours may be used.

As shown in Table 1, these ceramics have a Vickers hardness of 1200 to 2000 kg.
/ Mm ² , with a bending strength of 30 to 180 kg /
mm ² , fracture toughness (K _1c ) 4.0-7.0 MPa
^{Since it has} a high strength and a high toughness of 突起, there is almost no breakage of the projections 23 during dressing, and the polishing cloth can be dressed with good reproducibility. In addition, since these ceramics have excellent chemical resistance, they are less susceptible to corrosion even if the polishing liquid remains on the polishing cloth, so that they can be used for a long time.

When cermet is used as a material for forming the jig 21, one of cobalt (Co), nickel (Ni), molybdenum (Mo), and tungsten (W) or an alloy thereof is used in an amount of 3 to 15% by weight. %, WC, C
r ₃ C ₂ , Mo ₂ C, ZrC, VC, NbC, ZrN,
Carbides and nitrides such as NbN and TaN are 10-2 in total.
After forming into a plate having a desired shape a material containing 0% by weight and a balance of TiC and / or TiN, hot pressing is performed at a temperature of 1400 to 1500 ° C. for 1 to several hours in a vacuum atmosphere. What is necessary is just to use what was sintered, and when using a cemented carbide, cobalt (Co), nickel (N
i), 5 to 10% by weight of one of molybdenum (Mo) or an alloy thereof, and TiC, TiN, Cr ₃ C ₂ , Mo
₂ C, ZrC, VC, NbC, ZrN, NbN, TaN
Containing 5 to 10% by weight in total of carbides and nitrides such as
The remainder consisting of tungsten carbide (WC) was heated in a reduced pressure atmosphere at a temperature of 1400-1500 ° C.
What is fired for about several hours may be used.

As shown in Table 1, these cermets and cemented carbides also have a Vickers hardness of 145.
0~1800kg / mm ² of a hardness, high strength bend 140~300kg / mm ^2, fracture toughness value in the intensity (K _1c) In 6.5～11.0MPam ^1/2,
Since it has high toughness, there is almost no breakage of the projection 23 during dressing, and it can be used for a long time.

[0023]

[Table 1]

Then, the outer surface of the plate-shaped body formed and fired into a desired shape is subjected to shot blasting, ultrasonic processing, or cutting to form a tapered projection 23 having a desired shape. The dressing jig 21 of the present invention can be manufactured. In forming the projections 23, a convex surface corresponding to the projections 23 may be formed in advance in a mold, and may be formed integrally during press molding.

Further, in the present invention, the dressing jig 2
In the example shown in FIG. 1, one of ceramics, cermet, and cemented carbide is used. However, in order to improve the durability of the dressing jig 21 and the damage of the projection 23, at least the surface provided with the projection 23 has diamond. Film or diamond-like carbon (DLC) film 0.5 to 5 μm
May be applied in the range of.

[0026]

【Example】

(Example 1) A dressing jig 21 according to the present invention and a conventional diamond grindstone were used to sharpen a polishing cloth 3 made of foamed urethane resin provided on a polishing plate 1 of a CMP apparatus, and compared the two jigs 21. An experiment was performed.

The dressing jig 21 of the present invention is made of alumina ceramics having a purity of 99.5% and containing MgO, SiO ₂ , and CaO as sintering aids, having a height t of 0.3 mm and a side inclination. Angle 45 °, the maximum length R of the tip flat surface 23a is a quadrangular pyramid with a pitch width W2mm, and a protrusion 23 having a pitch of W2 mm is used. A diamond abrasive having an average particle diameter of 18 μm was coated on a surface of a stainless steel plate having an outer diameter of 100 mm with nickel (N
The one fixed in i) was used.

In this experiment, each time one semiconductor wafer 13 is polished, the polishing pad 3 is sharpened to measure the variation in polishing and the presence or absence of scratches on the semiconductor wafer 13, and the average value of 50 wafers is calculated. It was measured. The variation in polishing was measured by a racer-type film thickness measuring device, and the number of wafers was measured by counting the number of scratches that could be visually confirmed.

As a result, in the case of using the conventional diamond grindstone, the range of the maximum thickness and the minimum thickness is 0.75 to 0.75.
While the dressing jig 21 of the present invention has a maximum thickness and a minimum thickness in the range of 0.81 to 0.86 and a variation of about 0.05 μm, while the variations are 0.94 μm and about 0.2 μm. And the reproducibility of the polishing pad 3 is high.

In the case of using a conventional diamond whetstone, as many as eight pieces were found to have scratches visually, whereas in the dressing jig 21 of the present invention, one piece of scratches was found visually. I couldn't find anything.

As described above, by using the dressing jig 21 of the present invention, a polishing process can be performed without damaging a work piece having a small hardness and easily scratched like the semiconductor wafer 13 and the like. Since the polishing variation is small, it can be seen that the same amount can always be polished.

(Embodiment 2) Next, of the dressing jigs 21 having the same specifications as those in Embodiment 1, prototypes having different shapes of the projections 23 and different maximum lengths R of the flat surfaces 23a at the tips of the projections 23 were manufactured. Each time one semiconductor wafer 13 was polished by a CMP apparatus using these jigs 21, the polishing pad 3 was dressed, and an experiment was performed on polishing variations when the ten semiconductor wafers 13 were polished. .

Table 2 shows the shape of the projection 23 of the dressing jig 21, the maximum length R of the flat surface 23a at the tip of the projection 23, and the respective results.

[0034]

[Table 2]

As a result, it is found that the shape of the projection 23 such as a cone or a quadrangular pyramid hardly relates to the polishing variation, and the polishing variation increases as the maximum length R of the flat surface 23a at the tip of the projection 23 increases. If the maximum length R of the flat surface 23a at the tip of the projection 23 is 0.2 mm or less, the polishing variation can be reduced to 1 μm or less, which is very excellent.

[0036]

As described above, according to the present invention, in order to sharpen a polishing cloth provided on a polishing plate of a polishing apparatus, an outer surface of a plate made of one of ceramics, cermet, and cemented carbide is required. By providing a dressing jig with a plurality of tapered protrusions on the surface, the polishing cloth can be sharpened sharply and the abrasive remaining on the polishing cloth can be easily removed. it can. Therefore, even if the workpiece has a small hardness such as a semiconductor wafer, the workpiece can be polished or lapped without being damaged, and is always polished by a predetermined amount since polishing variation is small. be able to.

Moreover, the dressing jig is made of ceramics, cermets,
Since it is made of a cemented carbide, it can be used for a long time without damaging the tapered sharp projection.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a dressing jig according to the present invention.

2 (a) and 2 (b) are enlarged perspective views showing various shapes of projections which are main parts of FIG. 1. FIG.

FIG. 3 is a schematic view showing a general CMP apparatus.

[Explanation of symbols]

21 ... dressing jig 22 ... plate-like body
23: projection, 23a: flat surface

Claims (1)

[Claims] 1. A dressing jig comprising a plate-shaped body made of ceramics, cermet, cemented carbide or the like and having a plurality of tapered projections on an outer surface thereof.