JP2002127011A - Cmp conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CMP conditioner having sharp cutting performance and longer life. SOLUTION: In the CMP conditioner having single-layer super-abrasives fixed to the surface of a base, the super-abrasives contains the total 3 wt.% or more super abrasive grains each having a tetrahedral or octahedral shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a CMP conditioner. More specifically, the present invention relates to a CMP conditioner used for conditioning a polishing pad for CMP, which has a sharpness and a long life.
Regarding P conditioner.

[0002]

2. Description of the Related Art Multilayer wiring becomes more and more important in the high integration and high speed of VLSIs, and further enhancement is required for the planarization process of an interlayer insulating film and metal wiring which is the center of this technology. Is being done. In general, in a wafer processing apparatus for polishing the surface of a semiconductor wafer, a polishing pad is attached to a disk-shaped surface plate, one or more wafers are placed on the surface of the surface plate, and these wafers are placed on the polishing pad. A polishing liquid containing fine abrasive particles is supplied between a polishing pad and a wafer while being forcedly rotated by a carrier, and chemical mechanical polishing (CMP) is performed by chemical and mechanical action of an interface. As the polishing pad, a velor-type pad made of a polyester non-woven fabric impregnated with a polyurethane resin, a suede-type pad made of a polyester non-woven fabric as a base material and a foamed polyurethane layer formed thereon, or a foamed polyurethane pad having closed cells is used. Have been. Further, as the abrasive particles, ferrite powder, alumina powder, barium carbonate, colloidal silica, cerium oxide and the like are used,
As the polishing liquid, a potassium hydroxide solution, diluted hydrochloric acid, diluted nitric acid, aqueous hydrogen peroxide, an aqueous solution of iron nitrate, or the like is used. As such wafers are repeatedly polished, chips and abrasive particles of the work material enter the fine holes of the polishing pad and cause clogging, and the surface of the polishing pad is heated by chemical reaction heat between the abrasive particles and the wafer. Is mirror-finished, and the polishing rate decreases. For this purpose, the conditioning of the polishing pad must be performed constantly or periodically. Polishing pad conditioning requires a CMP conditioner with good sharpness and long life.
MP conditioners have been proposed. For example, Japanese Patent Application Laid-Open No. 9-1457 discloses a wheel dresser having a first ring grindstone and a second ring grindstone having different abrasive grain sizes as a wheel dresser capable of simultaneously obtaining a high truing ability and a good dressing effect. Has been proposed. Japanese Patent Application Laid-Open No. 10-12579 discloses a dresser capable of removing clogging of a polishing cloth and stabilizing a polishing rate, which contains gold, silver, copper or titanium and has a melting point of 700 to 700.
A dresser has been proposed in which diamond grains are brazed to an alloy at 1,100 ° C. so that the closest distance is 5 μm or more. Japanese Patent Application Laid-Open No. H11-868 discloses a dressing jig that stabilizes the polishing rate and suppresses the dropping of diamond particles during dressing and the abrasion of nickel plating. Dress jigs that have been mixed and fixed have been proposed. JP-A-2000-
Japanese Patent No. 24922 discloses a wheel dresser that stabilizes sharpness and reduces the detachment of abrasive grains, has a friction coefficient of 0.8 to 1.0 on the surface of the abrasive grain layer, and has a thickness of a plating layer for fixing the abrasive grains. A wheel dresser in which the grain size is 60 to 70% of the abrasive particle diameter has been proposed. Further, JP-A-2000-141206
Japanese Patent Laid-Open Publication No. H11-64139 discloses a polishing dresser that reduces the wear during use, prolongs the service life, and improves the polishing efficiency. The outer peripheral portion of the base member is raised, and the cross-sectional shape of the polishing surface with the polishing grid fixed to the raised portion is convex. There is proposed a polishing dresser which is formed in an arcuate curved surface having a flat top surface. As a CMP conditioner, a conditioner in which superabrasive grains are fixed to a single layer by plating or brazing on the surface of a substrate is often used. The super-abrasive grains for the CMP conditioner are preferably super-abrasive grains having a sharp tip when importance is placed on the sharpness of the polishing pad, but such super-abrasive grains have poor abrasion resistance and have a sharp tip. May be crushed. On the other hand, in order to extend the life of the conditioner, it is preferable to use superabrasive grains having good wear resistance. However, superabrasive grains having good wear resistance have no sharp tip and are inferior in sharpness. For this reason, a CMP conditioner having both excellent sharpness and long life has been demanded.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a CMP conditioner which is sharp and has a long life.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, fixed superabrasive grains containing superabrasive grains having a tetrahedral or octahedral shape. C
The MP conditioner was found to be excellent in sharpness and to maintain the sharpness for a long period of time, and based on this finding, completed the present invention. That is, the present invention
(1) In a CMP conditioner in which a single layer of superabrasive grains is fixed to the substrate surface, the superabrasive grains contain a total of 3% by weight or more of superabrasive grains having a tetrahedral or octahedral shape. To provide a CMP conditioner. Further, as a preferred embodiment of the present invention, (2) the particle size of the superabrasive having a tetrahedral or octahedral shape is equal to the particle size of another superabrasive, or the particle size of another superabrasive The CMP conditioner according to item 1 which is larger can be mentioned.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A CMP conditioner according to the present invention is a CMP conditioner in which a single layer of superabrasive grains is fixed to the surface of a substrate, wherein the superabrasive grains comprise tetrahedral or octahedral superabrasive grains. CMP containing at least 3% by weight
Conditioner. The shape of the CMP conditioner of the present invention is not particularly limited, and for example, a disk shape, a ring shape, or the like can be selected. The method for fixing the superabrasive grains of the CMP conditioner of the present invention is not limited. For example, an electrodeposition method, brazing, thermal spraying, metal bonding, or the like can be used, and an inversion method can be applied. The CMP conditioner of the present invention is a CMP conditioner in which superabrasive grains having a total amount of superabrasive grains having a tetrahedral or octahedral shape on a substrate surface in a total amount of 3% by weight or more are fixed to a single layer. The superabrasive grains may contain at least 3% by weight of one type of superabrasive grains having a tetrahedral or octahedral shape, or a total amount of both superabrasive grains having a tetrahedral or octahedral shape. 3% by weight or more. The superabrasive used in the present invention includes diamond abrasive and cBN.
Abrasive grains can be mentioned. At present, tetrahedral abrasive grains are not known as diamond abrasive grains, but octahedral diamond abrasive grains are present as so-called rough crystals in natural diamond abrasive grains and artificial diamond abrasive grains. Also present in small amounts. The tetrahedral cBN abrasive grains are, for example, cBN of the ABN800 series manufactured by De Beers and the cBN400 series manufactured by General Electric.
The octahedral cBN abrasive included in the N abrasive is, for example,
It is contained in cBN abrasive grains of ABN200 series manufactured by De Beers. FIG. 1 (a) is a schematic perspective view of a superabrasive having a tetrahedral shape, and FIG. 1 (b) is a schematic perspective view of a superabrasive having an octahedral shape. As superabrasive grains having a tetrahedral or octahedral shape used in the present invention, not only superabrasive grains having a perfect regular octahedral or regular tetrahedral crystal form, or ridges and corners are rounded, or A tetrahedral or octahedral superabrasive having a distorted crystal axis can also be used.

In the CMP conditioner of the present invention, only superabrasive grains having a tetrahedral or octahedral shape can be used, or a mixture of ordinary superabrasive grains and tetrahedral or octahedral superabrasive grains can be used. Can also be used. When using a mixture of ordinary superabrasive grains and superabrasive grains having a tetrahedral or octahedral shape, the proportion of superabrasive grains having a tetrahedral or octahedral shape is at least 3% by weight of all superabrasive grains. And more preferably at least 5% by weight of all superabrasives. When the proportion of superabrasive grains having a tetrahedral or octahedral shape is less than 3% by weight,
The sharpness and life of the CMP conditioner may not be sufficiently improved. The higher the content of superabrasive grains having a tetrahedral or octahedral shape, the greater the effect of improving sharpness and life is.However, because superabrasive grains having a tetrahedral or octahedral shape are expensive, CMP The cost of the conditioner increases. When using a mixture of normal superabrasives and superabrasives having a tetrahedral or octahedral shape, the particle size of the superabrasives having a tetrahedral or octahedral shape is the particle size of a normal superabrasive. It is preferable that the diameter is equal to or larger than the particle diameter of ordinary superabrasive grains. If the particle size of the superabrasive particles having a tetrahedral or octahedral shape is smaller than the particle size of ordinary superabrasive particles used in combination, the sharpness of the CMP conditioner may not be sufficiently improved. In the CMP conditioner of the present invention, twin (twi)
Since the superabrasives of n) have a problem of crushing or protruding more than necessary, the content is preferably 1% by weight or less, and more preferably 0.5% by weight or less. More preferred. The regular tetrahedron or regular octahedral superabrasive grains used in the CMP conditioner of the present invention have a uniform shape, so that an edge is easily formed, and the sharpness is good when used as a conditioner. Further, since the crystal morphology is excellent, a CMP conditioner having high wear resistance and a long life can be obtained.

[0007]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 A base metal having dimensions of 100D-20W-4T-60H was manufactured by lathing stainless steel (SUS304). Next, the surface was masked with an insulating tape and paint, leaving the diamond abrasive grain fixed surface. The base metal is subjected to alkaline degreasing treatment, immersed in a pretreatment liquid containing 240 g / L of nickel chloride and 100 g / L of hydrochloric acid, the base metal is set on the anode side, and electrolysis is performed at room temperature at a current density of 10 A / dm ² for 2 minutes. After etching, a base metal was set on the cathode side, and strike plating was performed for 3 minutes. Then, plating was performed at a current density of 1 A / dm ² for 15 minutes in a nickel sulfamate plating bath to form a base plating layer of 3 μm. Next, 93 parts by weight of diamond abrasive grains for artificial metal bond having a grain size of # 100 and grain size of # 10
A mixture of 7 parts by weight of octahedral diamond abrasive grains of 0 is placed, and a current density of 0.5 A is used in a nickel sulfamate plating bath to which an additive for controlling plating stress and hardness is added.
/ Dm ² for 3 hours to temporarily fix a single layer of diamond abrasive grains. Excessive diamond abrasive grains were removed, and embedded plating was performed at a current density of 1 A / dm ² for 1 hour. Then, a # 100 alumina abrasive stone was applied to remove the diamond abrasive grains serving as floating stones. Then, nickel chloride 2
After immersion in a pretreatment liquid containing 40 g / liter and hydrochloric acid 100 g / liter, a base metal was set on the anode side, and after a current density of 10 A / dm ² for 30 seconds at room temperature for electrolytic etching, the base metal was set on the cathode side. Then, strike plating was performed for 2 minutes. Next, plating was performed for 15 minutes at a current density of 1 A / dm ² in a nickel sulfamate plating bath, and a current density of 1 A / dm ² was further plated in the same nickel sulfamate plating bath.
² was plated for 7 hours, and plated to a thickness of about 100 μm so as to fix the diamond abrasive grains. All the masking was removed, and the base metal on which the diamond abrasive layer was formed was washed and dried to obtain a CMP conditioner. A conditioning test was performed using the obtained CMP conditioner. Polishing machine [Buhler, ECOMET4]
And polishing pad [Rodel Nitta, IC-1000]
Using a potassium hydroxide aqueous solution having a pH of 10.5 containing silica fine particles as a polishing solution under the conditions of a load of 19.6 kPa, a polishing pad rotation speed of 100 min ^-1 , a CMP conditioner rotation speed of 56 min ^-1 , and a conditioning time of 2 minutes. The removal amount of the polishing pad was 42.2 m / h. Further, a CMP test was performed using the obtained CMP conditioner. Same polishing machine and conditioning test, using a polishing pad and a polishing fluid, load 29.4 kPa, the polishing pad rotation speed 100 min ^-1, the workpiece rotational speed 56Min ^-1, processing time 2
Under the condition of minutes, the polishing rate was 173 nm / min. Example 2 Diamond abrasive grains 8 for artificial metal bond with a grain size of # 100 8
A CMP conditioner was prepared in the same manner as in Example 1 except that a mixture of 6 parts by weight and 14 parts by weight of regular octahedral diamond abrasive grains having a particle size of # 100 was used, and a conditioning test and a CMP test were performed. Polishing pad removal amount is 4
The polishing rate was 8.0 m / h, and the polishing rate was 167 nm / min. Example 3 Diamond abrasive grains 9 for artificial metal bond having a grain size of # 100 9
3 parts by weight and regular octahedral diamond abrasive grain # 80
A CMP conditioner was prepared in the same manner as in Example 1 except that the mixture in parts by weight was used, and a conditioning test and a CMP test were performed. Polishing pad removal amount is 47.7
m / h, and the polishing rate was 176 nm / min. Comparative Example 1 A CMP conditioner was prepared and a conditioning test and a CMP test were performed in the same manner as in Example 1, except that only diamond for artificial metal bond having a particle size of # 100 was used. The removal amount of the polishing pad was 36.1 m / h, and the polishing rate was 156 nm / min. Table 1 shows the results of Examples 1 to 3 and Comparative Example 1.

[0008]

[Table 1]

As shown in Table 1, the CMP conditioner of the present invention in which the diamond abrasive grains containing the octahedral diamond abrasive grains of Examples 1 to 3 were fixed was compared with the conventional product of Comparative Example 1. Thus, the sharpness of the polishing pad is good, and the polishing rate is high. Also, wear of the tip of the abrasive grains was not observed within the range of the test, and it is assumed that the wear resistance is high and the life is long.

[0010]

The tetrahedral or octahedral super-abrasive grains used in the CMP conditioner of the present invention have a uniform shape, so that an edge is easily formed, and the sharpness is good when used as a conditioner. Further, since the crystal morphology is excellent, a CMP conditioner having high wear resistance and a long life can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of superabrasive grains having tetrahedral and octahedral shapes.

Continued on the front page F term (reference) 3C047 EE18 3C058 AA09 AA19 CB10 DA02 DA17 3C063 AA02 AB01 BB02 BB06 BB24 BC02 BG07 CC13 EE26 FF08 FF23

Claims (1)

[Claims] 1. A CMP in which a single layer of superabrasive grains is fixed on a substrate surface.
A CMP conditioner, wherein the superabrasive grains contain a total of 3% by weight or more of superabrasive grains having a tetrahedral or octahedral shape.