JP3281563B2 - Vitrified bond tool and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vitrified bond tool, and more particularly to a CM in a semiconductor LSI manufacturing process.
The present invention relates to a vitrified bond tool suitable as a dressing tool for a polishing pad used in a P (chemical mechano polishing) process and a method for manufacturing the same. Further, the present invention relates to a polishing pad dressing apparatus using a vitrified bond tool.

[0002]

2. Description of the Related Art In a CMP process which is one of semiconductor LSI manufacturing processes, an LSI is polished by using a polishing pad made of urethane and free abrasive grains. This polishing pad is dressed using an electrodeposited diamond wheel. The electrodeposited diamond wheel has diamond abrasive grains fixed to a base metal by a metal bond, and the diamond abrasive grains are randomly arranged in the metal bond. This electrodeposited diamond wheel has diamond abrasive grains fixed to a base metal by an electroplating method. In the CMP step, a strong acid or an alkaline solution is used for efficient processing. The dressing of the polishing pad is performed in a step different from the CMP step using pure water to prevent metal elution.

[0003]

However, the use of such an electrodeposited diamond wheel has the following problems.

(1) Since the binder for fixing the base metal and the abrasive is a metal (metal bond), the metal is eluted in a strong acid or strong alkaline atmosphere and contaminates the LSI through the polishing pad. Can only be done offline.

(2) During use, some abrasives may fall off and bite into the polishing pad, which may damage the LSI.

The present invention provides a vitrified bond tool which can be used in-line in a CMP (Chemical Mechano Polishing) step in a semiconductor LSI manufacturing process and in which abrasive grains are firmly fixed to a support, and a method for manufacturing the same. That is the task.

[0007]

Means for Solving the Problems The present inventors disperse abrasive grains (for example, superabrasive grains such as diamond and cubic boron nitride) and a vitrified bond in a liquid organic binder, and form the mixture on a support (base metal). After the application of the thickness of the abrasive material in the thickness direction of 1 to 3 layers in the thickness direction, by sintering and fixing, the metal component is discarded from the tool component, the tool is composed of an inorganic component rich in chemical resistance, Even in a process in which the metal component has an adverse effect, in-line use becomes possible, and by further setting the abrasive layer to a thickness of 1 to 3 abrasive particles,
They have found that the abrasive grains are firmly fixed to the support to prevent the abrasive grains from falling off, and as a result of further intensive studies, they have completed the present invention.

In order to solve the above problems, a vitrified bond tool according to a first aspect of the present invention is characterized in that abrasive grains form a layer and are fixed to a base metal by vitrified bonds. “Abrasive grains form a layer” means that the abrasive grains are controlled and arranged at least in the thickness direction of the layer formed by the abrasive grains (arrangement along the fixed face of the abrasive grains as viewed from above the fixed face may be random) ), A state in which a set of abrasive grains forms a layer by itself. This state is easy to understand when the vitrified bond portion is eliminated from the sintered vitrified bond tool.

In order to solve the above-mentioned problems, a method of manufacturing a vitrified bond tool according to a second aspect of the present invention comprises positioning a screen having a predetermined print pattern on a base metal , and dispersing a slurry in which abrasive grains and vitrified bonds are dispersed. The abrasive grains form a layer on the base metal through the screen.
And Suyo coating, characterized by sintering.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A to 1C are schematic diagrams illustrating an abrasive layer according to an embodiment of the present invention.

Referring to FIG. 1 (A), abrasive grains 4 are
A single layer is formed on the surface and the head of the abrasive grains 4 is exposed, and the abrasive grains 4 are fixed by vitrified bonds 3. That is,
The overlapping of the abrasive grains 4 is eliminated in the thickness direction of the abrasive grain layer. For this reason, the abrasive grains 4 adhere to or very close to the surface of the support 1 and are fixed by the vitrified bond 3,
Abrasion of the abrasive grains 4 is highly prevented. In addition, the amount of expensive abrasive grains (particularly, super-abrasive grains such as diamond and CBN) is reduced. If the accuracy of the support is sufficiently high, dressing and truing are not required. Because the height of the abrasive grains is uniform (because only one abrasive layer is formed), the head of the abrasive grains can be exposed and fixed (the abrasive grains are arranged in a single row and arranged in a plane). This is because the use of vitrify bonds can be reduced). Further, since the abrasive layer is very thin, even if the support and the abrasive layer have different coefficients of thermal expansion, peeling, cracking, etc. of the abrasive layer due to thermal stress are prevented.

As shown in FIG. 1 (A), forming a single abrasive layer having a thickness of only one abrasive grain greatly increases the accuracy of the height of the abrasive grains. Although truing is not required, almost all abrasive grains are effective for grinding and can save expensive abrasive grains.
As shown in (B) and (C), a (two or three) abrasive layer having a layer thickness of several abrasive grains may be formed, and an upper layer is formed between the lower abrasive grains. May be interposed. As in the case of a single layer, abrasive grains are less likely to fall off, and the amount of expensive abrasive grains used is reduced.

When a large number of layers of abrasive grains are formed, the adhesive force of the abrasive grains is weak, and the upper layer of abrasive grains may fall off. Therefore, if the used amount of the vitrified bond is increased, the head of the abrasive grains is not exposed in the sintered state, so that dressing is required. Further, it is difficult to obtain the accuracy of the height of the abrasive grain layer by forming a large number of layers, so that dressing and truing are also required. The above tendency is particularly observed when four or more abrasive layers are formed.

As the material of the support, it is preferable to use ceramics such as aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, mullite and zirconia. More preferably, it is a ceramic having a coefficient of thermal expansion close to the coefficient of thermal expansion of the abrasive used. Since the support is made of a ceramic, glass, or a composite material thereof containing no metal component, the tool of the present invention is made of a vitrified bond tool. Thus, dressing of the polishing pad used in the CMP step, which is one of the LSI manufacturing processes, can be performed in-line. This tool is suitable, for example, as a polishing tool after cutting a wafer made of silicon crystal and a dressing tool thereof, a tool for forming a processing strain layer on the back surface of the wafer to remove contaminant impurities in the wafer, and a dressing tool therefor. Can be used for In addition, in fields where metal components and rust are not generated, precision grinding and sharpening are required,
The tool of the present invention is suitably applied. For example, the use of the tool of the present invention for polishing a fishing hook in which an electrodeposited diamond whetstone has been used conventionally prevents generation of rust.

As the vitrified bond, borosilicate glass, crystallized glass, quartz glass or the like can be used. Preferably, a vitreous material having a thermal expansion coefficient close to that of the abrasive used is preferred.

The abrasives (abrasives) used are preferably diamonds which have high strength and are chemically stable, but other superabrasives such as CBN, and general abrasives include alumina abrasives Alternatively, a silicon carbide abrasive may be used. For example, WA (white alundum), GC (green silicon carbide), polycrystalline alumina, or the like can be used. Preferably, abrasive grains having an average particle diameter of # 80 to # 300 and an average particle diameter of 3 μm or more are used. The ratio between the abrasive grains and the vitrify bond is preferably 1.1 to 1.2.

Further, as described above, the thickness of the layer of the abrasive layer to be fixed is set at 3 from the viewpoint of the holding power of the abrasive grains.
Layer or less structures are desirable. Preferably, a one-layer structure is desirable.

Preferably, a convex portion is formed on the support, and an abrasive layer is formed on the convex portion, so that even if the abrasive layer is extremely thin, the base surface of the support on which the abrasive is not fixed is provided. (A surface lower than the convex portion) and the work are prevented from contacting each other. Further, the positioning of application of the paste to be the abrasive layer is facilitated, and it is not necessary to provide abrasive particles on the entire surface of the support, thereby reducing the manufacturing cost. Such a convex portion can be provided in any shape, and can be used in place of an abrasive layer formed in contact with the support base surface. The level difference between the convex portion and the support base surface is about several 100 μm to several mm, preferably 0.5 mm.
About 5 mm, more preferably about 1 mm,
The ratio of this step and the thickness of the support base excluding the step relative to the base of the projection is preferably about 1/2 to 1/8. In addition,
The abrasive layer can have various shapes depending on the object to be polished and the abrasive. Preferably, the abrasive grain layer is formed by a screen method, but a green sheet containing abrasive grains may be prepared, die-cut, and adhered to a support. Further, the abrasive layer may be formed on the support via an intermediate layer.

FIGS. 2A to 2C show various aspects of a vitrify bond tool according to an embodiment of the present invention.
In FIG. 2A, a predetermined abrasive layer is formed on both side surfaces and the peripheral surface of the support. In FIG. 2B, a convex portion is provided at the end of the support,
A predetermined abrasive layer is formed over the surface of the convex portion. FIG. 2 (C)
Here, a plurality of small disc-shaped predetermined abrasive layers are divided and arranged on a large disc-shaped support.

Further, the vitrified bond tool of the present invention can be suitably applied to a known polishing apparatus and a sharpening apparatus, particularly a sharpening apparatus for a polishing pad, provided with a means for driving a tool and a means for fixing a work. The vitrified bond tool of the present invention is applicable to other types of polishing apparatuses.

[0021]

An embodiment of the present invention will be described below with reference to the drawings. 3A and 3B are diagrams for explaining the structure of the support of the vitrified bond tool according to one embodiment of the present invention, wherein FIG. 3A is a radial cross-sectional view and FIG. 3B is a plan view. Diamond abrasive grains were fixed to the support shown in FIG. 3 by vitrified bond to produce a vitrified bond tool. First, a method for manufacturing this tool will be described.

10 parts by weight of sodium borosilicate glass pulverized to an average particle diameter of 3 μm is added to 10 parts by weight of glycerin and mixed well to produce a slurry. Next, 20 parts by weight of a grain size # 120/140 diamond abrasive are put into the slurry and mixed well to form a paste.

The outer peripheral portion has an angle of 8 every 45 ° along the circumferential direction.
Silicon nitride having a diameter of 100 mm, on which two projections 2 are formed;
A disk-shaped support (base metal) 1 having a thickness of 5 mm (including the height of the convex portion 2) was prepared. The protrusion height of the protrusion 2 from the support 1 is 1 mm, and the distance between the inner end of the protrusion 2 and the center of the support 1 is φ.
92, the gap between the protrusions 2 in the circumferential direction was 4 mm. Therefore, the ratio of the step 1 mm of the projection 2 to the thickness 4 mm of the base of the support 1 is 1: 4. A screen (wire mesh) having a predetermined pattern of stainless steel with a mesh size of 270 μm and a wire diameter of 140 μm was laid on the support 1 such that a paste layer was formed on the tip surface of the convex portion 2, and was prepared as described above. The paste containing diamond abrasive was poured, and the surface of the screen was traced with a rubber spatula so that the paste containing diamond abrasive entered the eyes of the screen. At the same time, excess paste on the top of the screen was scraped off, and a paste layer corresponding to the thickness of the screen was formed on the front surface of the projection 2. Since the grain size of the # 120/140 diamond abrasive grains 4 is about 130 μm, the support 1
A layer of diamond abrasive was formed.

Next, the support 1 coated with the paste is
The resultant was fired in an electric furnace at 900 ° C. for 2 hours in a nitrogen atmosphere, and the diamond abrasive grains 4 were sintered and fixed to the front end face of the projection 2 of the support 1 with the vitrified bond 3.

As a comparative example, one obtained by electrodepositing # 120/140 diamond abrasive grains (polishing material) on a steel base metal having a diameter of 100 mm using a metal bond (nickel) was used.

FIGS. 4A and 4B are photographs showing the ceramic structure of the vitrified bond tool according to one embodiment of the present invention, wherein FIG. 4A is an enlarged photograph of a diamond abrasive layer, and FIG. Is a photograph further enlarging (A). 4 (A) and 4 (B), it was confirmed that almost one layer of the diamond abrasive layer was exposed to the head of the abrasive grain and was fixed to the tip surface of the convex portion 2 of the support 1.

[Test Example 1] The tools of Examples and Comparative Examples were
After being immersed in an acidic solution of pH 3 for 5 hours, ultrasonic cleaning was performed, and the amount of the dropped diamond abrasive grains was investigated.

[Test Example 2] The tools of Examples and Comparative Examples were
After being immersed in an alkaline solution of pH 10 for 5 hours, ultrasonic cleaning was performed, and the amount of the dropped diamond abrasive grains was investigated.

Table 1 shows the results of Test Examples 1 and 2.

[0030]

[Table 1]

Referring to Table 1, it was confirmed that the tool of the present example hardly dropped off the abrasive in an acidic atmosphere or an alkaline atmosphere, and a good holding force was obtained. On the other hand, according to the tool of the comparative example, the abrasive grains fell off in both acidic and alkaline atmospheres.

[0032]

As described above, according to the present invention,
Accuracy of the thickness of the abrasive layer is increased, and dressing and truing are not required. Further, the abrasive grains are firmly fixed physically and chemically to the support, and the abrasive grains are prevented from falling off to a high degree. In particular, by setting the thickness of the abrasive layer to one to three abrasive grains, expensive abrasive grains (particularly diamond, CB
N) is reduced. In this way, the abrasive grains are prevented from falling off, and the binder that fixes the abrasive grains to the support is made of vitrified bond, that is, a ceramic material, so that the binder does not elute in a strong acid and strong alkaline atmosphere. When dressing a polishing pad for LSI polishing, the binder is LS through the polishing pad.
There is no danger of contaminating I, and the danger that dropped abrasive grains will cut into the polishing pad and damage the LSI will be reduced. Therefore, dressing of the polishing pad can be performed in-line. The vitrified bond tool of the present invention having such characteristics is suitably used in a field where an electrodeposited diamond tool has been used in the past.

By applying the screen method to the method for manufacturing a vitrified bond tool of the present invention, the thickness of the abrasive grains is limited, and it is particularly preferable that the thickness of the abrasive grains is only one, and the overlap of the abrasive grains is reduced. In addition, an extremely thin abrasive layer having an exposed abrasive head can be easily formed.

[Brief description of the drawings]

FIGS. 1A to 1C are schematic diagrams for explaining an abrasive layer according to an embodiment of the present invention. FIG. 1A shows a single-layer abrasive grain for one abrasive grain. Layer, an abrasive layer for two abrasive grains in (B),
(C) shows an abrasive layer for three abrasive grains.

FIGS. 2A to 2C are schematic views for explaining various aspects of a vitrify bond tool according to an embodiment of the present invention, wherein FIG. A tool in which a predetermined abrasive layer is formed on the surface, a tool in which a predetermined abrasive layer is formed over the surface of the convex portion, wherein
(C) shows a tool in which a plurality of small disc-shaped predetermined abrasive layers are divided and arranged on a large disc-shaped support.

FIG. 3 is a view for explaining a structure of a support of the vitrified bond tool according to one embodiment of the present invention, and FIG.
Is a radial cross-sectional view, and (B) is a plan view.

FIGS. 4A and 4B are photographs showing the ceramic structure of the vitrified bond tool according to one embodiment of the present invention, wherein FIG. 4A is an enlarged photograph of a diamond abrasive layer,
(B) is an enlarged photograph of (A).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support (base metal) 2 Convex part 3 Vitrified bond 4 Diamond abrasive

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/304 622 H01L 21/304 622M (72) Inventor Kotoshi Watanabe 3-36 Noritakeshinmachi, Nishi-ku, Nagoya-shi, Aichi Pref. Noritake Co., Ltd. (72) Inventor Naoya Kikuchi 3-36, Noritakeshinmachi, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Co., Ltd. (72) Inventor Junji Ishizaki 3-1-1, Noritakeshinmachi, Nishi-ku, Nagoya-shi, Aichi No. 36 Noritake Co., Ltd. Limited (56) References JP-A-7-328937 (JP, A) JP-A-63-207564 (JP, A) JP-A 10-180615 (JP, A) Sho 63-158765 (JP, U) Shokai 58-110369 (JP, U) Shohei 6-50753 (JP, U) (58) Fields investigated (Int. Cl. ⁷⁾ B24D 3/00 310 B24D 3/00 340 B24D 3/14 B24B 37/00 B24B 53/12 H01L 21/304 622

Claims (6)

(57) [Claims] The present invention is used for a CMP process in a semiconductor manufacturing process.
Vitrified bon for dressing tools for polishing pads
A de tool, the abrasive grains in layers, vitrified bond tools, characterized in that secured to the base metal by vitrified bond. 2. The abrasive layer formed by the abrasive grains is formed of the abrasive grains 1 to
The vitrified bond tool according to claim 1, wherein the tool has a layer thickness of three pieces. 3. The abrasive grain according to claim 1, wherein the abrasive grains are fixed along a surface to be fixed in a single layer so as not to overlap in the thickness direction of the abrasive grain layer. Vitrified bond tool. 4. The bididified bond tool according to claim 1, wherein the base metal is made of a ceramic and / or glass containing no metal component. 5. A semiconductor device according to claim 1, wherein said semiconductor device is used in a CMP process during a semiconductor manufacturing process.
Vitrified bon for dressing tools for polishing pads
A method of manufacturing a tool , comprising positioning a screen having a predetermined print pattern on a base metal, and forming a layer on the base metal through a slurry in which abrasive grains and vitrified bonds are dispersed. A method for producing a vitrified bond tool, comprising applying and sintering. 6. The production of a vitrified bond tool according to claim 5, wherein the slurry is applied such that the abrasive layer after sintering has a thickness of 1 to 3 abrasive grains. Method.