JP2003200344A - Rotary joint for cmp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary joint that can appreciably conduct a flow of fluid between relatively rotatable members of a CMP (chemical mechanical polishing) device and can sufficiently counteract contamination. <P>SOLUTION: A joint body 1 and a rotor 2 form a fluid passage 4 connected in series by an end face contact type mechanical seal 3 comprising sealing rings 11 and 12 of silicon carbide. At least either of both sealing rings 11 and 12 comprises a composite silicon carbide sintered body where globular carbon is dispersed in a compact silicon carbide structure. The composite silicon carbide sintered body forms a graphitized intermediate layer between the globular carbon and the surrounding silicon carbide structure. The intermediate layer has a Raman spectral intensity showing SP2 scattering of graphite higher than that of a center region of the globular carbon about a Raman shift of 1,590 cm-1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to CMP (Chem).
ical Mechanical Polish
g) A rotary joint provided in the apparatus, which relates to a rotary joint for a CMP apparatus for causing positive pressure and negative pressure fluids such as gas, liquid, slurry fluid (solid-liquid mixed fluid) to flow between relative rotating members Is.

[0002]

2. Description of the Related Art A surface polishing process for a semiconductor wafer by a CMP apparatus is performed by rotating a turntable and a top ring separately and independently while the semiconductor wafer is sandwiched between them. In addition, various fluids such as air, water supply, polishing agent, oxidizing agent, pH adjusting agent, etc. for performing vacuum suction, air spout, water spout, etc. for vacuum suction of a semiconductor wafer or a surface plate from a turntable or top ring. Are supplied. Therefore, C
In the MP device, a rotary joint is provided between the CMP device main body and a turntable or top ring rotatably supported by the CMP device main body to allow such negative pressure and positive pressure fluid to flow without causing leakage thereof. I need to put it.

Thus, conventionally, a CM which is a fixed member
P As a rotary joint that connects the fixed-side flow path formed in the main body of the apparatus and the rotary-side flow path formed in the turntable or top ring that is the rotary-side member, to the joint main body and the rotary-side member that are attached to the fixed-side member A rotary body to be rotatably connected to each other, and a flow path formed in the joint body and a flow path formed in the rotary body are provided with a first sealing ring provided in the rotary body and a second sealing provided in the joint body. By the end face contact type mechanical seal composed of a ring,
It has been proposed that they are connected in communication to form a series of fluid passages.

[0004]

By the way, it is extremely important to take measures against contamination in a CMP apparatus, and it is necessary that the rotary joint used for this has a structure in which contaminants are not mixed. is there. In particular, in a mechanical seal that connects both flow paths, since both sealing rings are in sliding contact with each other relative to each other, contaminants (wear particles) are likely to be generated, and it is necessary to take sufficient measures against them.

Therefore, conventionally, both sealing rings are made of silicon carbide (dense silicon carbide sintered body) which is excellent in wear resistance in addition to corrosion resistance and the like to prevent generation of wear powder. It has been suggested to prevent it.

However, since silicon carbide does not have a self-lubricating property like carbon, it has a high coefficient of friction between both sealing rings, so that noise due to mutual friction at the relative rotary sliding contact portions of both sealing rings is generated. Occurs (this is a phenomenon generally called "squeaking", which is hereinafter referred to as "squeaking"). The occurrence of such squeal is remarkable under a dry condition such as when a gas such as compressed air is caused to flow or when vacuum suction is performed, and particularly at an early stage when relative rotation is started. Even when both seal rings are made of silicon carbide, it is difficult to say that a reliable contamination prevention measure can be taken because abrasion powder is generated in the relative rotary sliding contact portions of the seal rings under dry conditions.

[0007] Conventionally, in order to solve such a problem, one of the sealing rings should be composed of (a) a porous silicon carbide sintered body, and (b) a porous silicon carbide. And impregnate the pores with a low-friction material such as oil or fluororesin, or infiltrate a low-friction metal material such as silver, lead, antimony, etc. (c) Fine solid lubricant ( It has been proposed to construct a composite silicon carbide sintered body in which carbon, graphite, boron nitride, molybdenum disulfide, etc.) are dispersed, but in both cases, both sealing rings are made of dense material. The same problem as in the case of using the above silicon carbide sintered body remains. That is, in the case of (a), the porous surface of the sliding surface (sealing end surface) in the sealing ring made of porous silicon carbide functions as a kind of oil pot, and a fluid is formed between the sealing ring made of the other dense silicon carbide. Form and hold a lubricating film,
Although it is possible to improve slidability between both sealing rings and prevent generation of abrasion powder, such an oil pot function is not exhibited under dry conditions, and porous silicon carbide is inferior in strength. On the contrary, there is a fear that the wear is accelerated. Further, in the case of (b), since the bonding force between silicon carbides in the porous silicon carbide sintered body is weak, the wear resistance is poor, and there is a problem in durability as a sliding body (sealing ring), and When the moving surface becomes high temperature due to frictional heat, the impregnating material and the infiltrating material evaporate and decompose from the sliding surface to contaminate the fluid, so that it cannot be applied to a rotary joint for a CMP device which requires a countermeasure against contamination. Further, in the case of (C), since the lubricant that hinders the sintering behavior is dispersed throughout the sintered body, the density and strength (bending strength) are reduced, and there are problems in wear resistance and durability. Occurs. In addition, although the lubricant particles such as graphite particles are bonded to the silicon carbide particles to a certain extent, since the bonding force (sintering force) is weak, the silicon carbide particles are shed at the boundary between the two, and this is sealed. There is a risk that the so-called grindstone action will be exerted between the rings to wear and damage the sealed end face.

The present invention has been made in view of the above points, and in particular, by devising the material of the sealing ring, the properties of the fluid to be used (liquid, gas, etc.) and flow conditions (positive pressure, negative pressure). The present invention aims to provide a rotary joint for a CMP device, which is capable of satisfactorily flowing the fluid between relative rotating members without causing leakage, and has taken sufficient measures against contamination, regardless of pressure conditions such as It is what

[0009]

SUMMARY OF THE INVENTION According to the present invention, a flow path formed in a joint body and a flow path formed in a rotary body that is rotatably connected to the joint main body are provided in the rotary body and are made of silicon carbide. In a rotary joint for a CMP device, which is connected in series to form a series of fluid passages by an end-face contact type mechanical seal composed of a first sealing ring and a second sealing ring made of silicon carbide provided in the joint body. In order to achieve the above-mentioned object, in particular, at least one of the first and second sealing rings is made of a composite silicon carbide sintered body in which spherical carbon particles are arranged in a dense silicon carbide structure in scattered dots. It is a suggestion to leave.

In the above-mentioned composite silicon carbide sintered body, the silicon carbide structure is densified by the bonding of silicon carbide particles and self-contraction during firing. On the other hand, the spherical carbon arranged in the silicon carbide structure is surrounded by the silicon carbide particles, but the bonding and contraction behavior of the silicon carbide particles are uniformly received. That is, the portion forming the silicon carbide structure largely contracts during sintering (generally,
Since the volume of silicon carbide is reduced by about 1/2 during sintering, the spherical carbon is strongly compressed by the contracting force of the silicon carbide structure portion surrounding it. Since the spherical carbon has a spherical shape, the compressive force acts evenly on the outer peripheral surface of the spherical carbon. As a result, the bonding force between the spherical carbon and the silicon carbide particles is significantly increased by the compression action from the outer peripheral side due to the contraction of the silicon carbide structure portion. In particular, since the compressive force due to contraction acts evenly on the spherical carbon, the retaining force of the spherical carbon due to contraction becomes extremely strong and the physical binding force becomes extremely large.

From these facts, the spherical carbon is firmly held in the dense silicon carbide structure. As a result, a good and stable lubrication function (sliding function) can be exhibited even under severe conditions such as dry operation without easily falling off. That is, the lubricity can be improved without deteriorating the original characteristics of silicon carbide.

Further, in the above-mentioned composite silicon carbide sintered body, an intermediate layer considered to be a SiC-C bond is formed in the boundary region between the spherical carbon and the silicon carbide structure portion during firing. That is, a graphitized intermediate layer is formed between each spherical carbon and the surrounding silicon carbide structure. In the intermediate layer where graphitization has progressed, SP2 of graphite was found near the Raman shift of 1590 cm ^-1.
The Raman spectrum intensity showing scattering is higher than the intensity at the center of the spherical carbon, and the three-dimensional S
It is presumed that the amorphous state with a strong P3 structure (diamond structure) color was transferred to the amorphous state with a strong two-dimensional SP2 structure (graphite structure) color. Therefore, the sliding characteristics are further improved by forming the intermediate layer on the peripheral edge of the spherical carbon. The thickness of the intermediate layer is required to be at least 1 μm, and more preferably 4 to 10 μm, in order to significantly improve the sliding characteristics due to the presence of the intermediate layer.

The spherical carbon is, for example, a thermosetting resin (phenolic resin, melamine resin, urea resin, epoxy resin, etc.) or a tacky semi-solid or solid hydrocarbon mixture of bituminous blue (natural asphalt, coal). It is obtained by heat-treating a spherical material (tar / pitch, heavy petroleum oil, etc.) and has excellent slidability, but the average particle diameter of this spherical carbon (hereinafter referred to as "carbon diameter") Is less than 5 μm or the content of spherical carbon with respect to carbon silicon (the content is given by (content of spherical carbon / content of silicon carbide) × 100, and hereinafter referred to as “carbon content”. 2) is less than 2% by weight, the function of improving the lubricity (sliding property) by the spherical carbon cannot be sufficiently exerted. In order for the spherical carbon to sufficiently exhibit the function of improving lubricity, it is necessary that the carbon diameter is 5 μm or more and the carbon content is 2% by weight or more. In particular,
When the carbon diameter is 10 μm or more and the carbon content is 5 wt% or more, the function of improving lubricity by the spherical carbon is remarkably exhibited. However, if the carbon diameter exceeds 100 μm or if the carbon content exceeds 30% by weight, the above-mentioned carbon-silicon structure portion cannot retain spherical carbon and the silicon carbide structure is not dense. In order to maintain the spherical carbon and the denseness of silicon carbide, it is necessary that the carbon diameter is 100 μm or less and the carbon content is 30% by weight or less. In particular, when the carbon diameter is 50 μm or less and the carbon content is 20% by weight or less, the retention of spherical carbon by the carbon silicon structure portion becomes extremely strong and the silicon carbide structure can be sufficiently densified. . Therefore, in order to improve the lubricity without impairing the original characteristics of silicon carbide, the carbon diameter should be 5 to 5.
100 μm and a carbon content of 2 to 30% by weight
Is more preferable, the carbon diameter is 20 to 50 μm, and the carbon content is more preferably 5 to 20% by weight.

Further, in the rotary joint of the present invention, one of the first and second sealing rings is made of the above-mentioned composite silicon carbide sintered body (the other sealing ring is of a general dense quality). By using a silicon carbide sintered body), the coefficient of friction between the sealing rings can be significantly reduced, and no squeal or abrasion powder is generated even under dry conditions.
Although it is possible to perform good sealing between the flow paths, such an effect can be more remarkably exhibited when both the sealing rings are made of the composite silicon carbide sintered body. Therefore, as a countermeasure against contamination in the CMP apparatus, it is best to configure both sealing rings with the above-mentioned composite silicon carbide sintered body.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
~ It demonstrates concretely based on FIG.

CM according to the present invention in this embodiment
As shown in FIG. 1, the rotary joint R for the P device is attached to the joint main body 1 attached to the fixed side member (for example, the CMP device main body) and the rotary side member (for example, the top ring or turntable of the CMP device). Rotating body 2 and mechanical seal 3 interposed between the two bodies 1 and 2.
And a series of fluid passages 4 formed on both bodies 1 and 2 via a mechanical seal 3. In the following description, the upper and lower sides mean the upper and lower sides in FIG.

As shown in FIG. 1, the joint body 1 has a tubular shape with its upper end closed, and has a cylindrical side wall 6 having a circular inner peripheral portion and its upper end closed. The end wall 7 is attached accordingly. The side wall 6 has a vertically divided structure.

As shown in FIG. 1, the rotating body 2 has a columnar shape and is concentrically arranged in the side wall 6 of the joint body 1 except for the lower end portion. It is rotatably connected via a pair of upper and lower bearings 8, 8. An O-ring 9 and a screw portion 10 for connecting to a rotary member are provided at the lower end of the rotating body 2 protruding from the joint body 1.

The mechanical seal 3 is, as shown in FIGS. 1 and 2, a first sealing ring 11 provided at the upper end of the rotating body 2.
A second sealing ring 12 provided at the lower end of the joint body 1, rotation preventing means 13, 14 interposed between the second sealing ring 12 and the joint body 1, and a spring member 1.
5 is provided.

As shown in FIGS. 1 and 2, the first sealing ring 11 is composed of an annular body portion 16 and a cylindrical fitting portion 17 integrally formed at the lower end portion thereof. Part 17
Is fitted to the fitted portion 18 which is the upper end portion of the rotating body 2 so as to be fitted and fixed to the rotating body 2 concentrically with the rotation axis thereof. The upper surface of the main body portion 16 is a sealed end surface (hereinafter also referred to as “sliding surface”) that is a smooth annular flat surface orthogonal to the axis.
11a. The fitting part 17 and the fitted part 18 are
They are connected to each other via an O-ring 19 and a drive pin 20 so that they cannot rotate relative to each other.

As shown in FIGS. 1 and 2, the second sealing ring 12 comprises an annular main body portion 21 and a cylindrical holding portion 22 integrally formed at the upper end portion thereof.
Is fitted into a holding hole (which constitutes an inner side flow passage of a second passage 29 described later) provided in the end wall 7 to form a concentric opposed state with the first sealing ring 11 and to be attached to the joint body 1. It is held so that it can move in the axial direction. Holding part 22
The fitting portion between the holding hole 29a and the holding hole 29a is secondarily sealed by an O-ring 24 held on the inner peripheral portion of the holding hole 29a. The outer peripheral portion of the main body portion 21 projects radially from the outer peripheral portion of the holding portion 22. As shown in FIG. 2, the lower end portion of the second sealing ring 12 (the lower end portion of the main body portion 21) has its outer peripheral surface formed into a downwardly tapered surface and its inner peripheral surface formed into a downwardly expanded tapered surface. By doing so, the tip end surface (lower end surface) is formed as a sealed end surface (hereinafter also referred to as a "sliding surface") 12a forming an annular surface having a minute width W. That is, the sealing end surface 12a of the second sealing ring 12
Are configured in a pointed shape that can come into contact with the sealing end surface 11a of the first sealing ring 11 in a concentric manner. The radial width W of the sealed end surface 12a is generally 0.1 to 4.0 mm in consideration of strength, contact pressure with the mating sealed end surface 11a, and the like.
(More preferably 0.4 to 2.0 mm).

As shown in FIGS. 1 and 2, the rotation preventing means has a holding hole 2 at the lower end of the end wall 7 of the joint body 1.
9a, one or a plurality of locking pins 13 are provided to project downward, and one or a plurality of engaging recesses 14 are formed on the outer peripheral portion of the main body portion 21 of the second sealing ring 12. do it,
By engaging the locking pin 13 with the engaging recess 14,
The second sealing ring 12 is locked and held so as not to rotate relative to the joint body 1 while allowing the second sealing ring 12 to move in the axial direction.

As shown in FIGS. 1 and 2, the spring member 15 is interposed between the outer peripheral portion of the main body portion 21 of the second sealing ring 12 and the lower end portion of the end wall 7 of the joint main body 1 facing the outer peripheral portion. It is composed of multiple coil springs mounted,
The second sealing ring 12 is pressed and urged toward the first sealing ring 11 so that the two sealing end faces 11a and 12a are pressed against each other.

The mechanical seal 3 constructed in this way
Is due to the relative rotational sliding contact action of the sealed end surfaces 11a and 12a accompanying the rotation of the rotating body 2, and the inner peripheral side region (in the central holes 26 and 28 of the sealing rings 11 and 12) and the outer peripheral side of the relative rotational sliding contact portion. It seals the area and exhibits the same sealing function as a known end-face contact type mechanical seal. An oil seal 30 is provided between the two bodies 1 and 2 for partitioning a region where the mechanical seal 3 is arranged and a region where the bearings 8 are arranged. Further, the side wall 6 of the joint body 1 is formed with a drain passage 31 that opens to a region where the mechanical seal 3 is arranged.

The fluid passage 4 is, as shown in FIGS. 1 and 2,
An inner-side flow passage port 27a, which is formed in the rotating body 2 so as to penetrate through the axial center portion thereof and opens at the upper end portion of the rotating body 2, is formed in the central hole of the first sealing ring 11 (in the central portion of the main body portion 16). The first flow path 27 communicating with the through hole 26) and the end wall 7 of the joint body 1 are formed.
A second flow path 29 in which an inner side flow path opening 29a that opens in the center of the lower surface of the second communication ring 28 communicates with a center hole (a through hole formed in the center of the main body 21 and the holding portion 22) 28 of the second sealing ring 12; Are connected in series by the mechanical seal 3. That is, the fluid passage 4 connects the inner side flow passage port 27a of the first flow passage 27 and the inner side flow passage port 29a of the second flow passage 29 by the both sealing rings 11 and 12 so as to be relatively rotatable. It is composed of a series of gas, liquid,
A positive pressure fluid 5a such as a slurry fluid or a negative pressure fluid (a gas or the like that flows in a direction opposite to the positive pressure fluid 5a in a state where the pressure inside the rotary joint R is negative due to vacuum suction or the like) 5b is provided in both flow paths 27, It is made possible to flow between 29 without leaking.

The fluid 5 is excluded except for the sealing rings 11 and 12.
The portions where a and 5b come into contact are made of a material that does not cause contamination due to contact with the fluids 5a and 5b. That is, the rotating body 2 and the end wall 7 in which the flow paths 27 and 29 are formed depend on joint use conditions such as the properties of the fluids 5a and 5b, but due to contact with the fluids 5a and 5b, elution and wear of metal components and the like are caused. It is preferable to use a plastic that does not generate dust such as powder and has heat resistance, corrosion resistance or chemical resistance. Generally, particles are generated by contact with the fluids 5a and 5b. PEEK, PES, PC and other engineering plastics that have no dimensional stability and heat resistance due to processing, and PTFE that has excellent corrosion resistance, chemical resistance, etc.,
It is made of fluorine-based plastic such as PFA, FEP and PVDF. Further, the O-rings 19 and 24 that may come into contact with the fluids 5a and 5b may be made of general rubber, or depending on the properties of the fluids 5a and 5b (for example,
It is preferable to use a fluororesin or a fluororubber (for example, "Viton" or "Kalrez" manufactured by DuPont) when it is a corrosive fluid.
In this example, the rotating body 2 and the end wall 7 are made of PEEK, the joint body parts other than the end wall 7 are made of metal, and all the O rings including the O rings 19 and 24 are made of fluororubber. There is.

By the way, in the mechanical seal 3,
In order for the sealing function to be exhibited well, both sealing end faces 1
It is necessary for 1a and 12a to be maintained in an appropriate contact state, but even if the pressure in the fluid passage 4 fluctuates due to the flow conditions of the fluids 5a and 5b (switching between positive pressure and negative pressure, etc.) The balance ratio κ of the mechanical seal 3 is set to 0 ≦ κ ≦ so that 11a and 12a are maintained in an appropriate contact state.
It is preferable to set it to be 0.6.

The balance ratio κ of the mechanical seal 3 is
As shown in FIG. 2, inside and outside the sealing end face 12a of the second sealing ring 12.
Diameter D₁, D₂And the outer diameter D of the holding portion 22 of the second sealing ring 12₀
, And by design, κ = ((D₀)²−
(D₁)²) / ((D₂)²-(D₁) ²)
You can That is, the relative rotation of the two sealing rings 11 and 12
The apparent surface pressure (thrust) Pa acting on the contact part is the axis
The first sealing ring 1 to the second sealing ring 12 which is movable in the direction
With the pressure (back pressure) P due to the fluid acting to press 1
With the pressure (spring pressure) F by the spring member 15
Therefore, Pa = (π / 4) ((D₀)²−
(D₁)²) P / (π / 4) ((D₂)²−
(D₁)²) + (Π / 4) ((D₂)²-(D₁)²)
F / (π / 4) ((D₂)²-(D₁)²) = (((D
₀)²-(D₁)²) / ((D₂)²-(D₁)²))
It is given by P + F, and the back pressure P in this equation
Coefficient of ((D₀)²-(D₁) ²) / ((D₂)²−
(D₁)²) Is the balance ratio κ. Thus, D₀, D
₁, D₂Should be designed so that 0 ≦ κ ≦ 0.6.
Even if the pressure in the fluid passage 4 fluctuates,
The thrust Pa at the relative rotational sliding contact portions of the sealing rings 11 and 12 is
The contact pressure of both sealed end faces 11a and 12a does not change significantly.
It can be held properly. If κ <0, then
There are problems such as making the pulling pressure F higher than necessary.
Therefore, if κ> 0.6, the negative pressure causes back pressure.
There is a risk that the contact pressure between the sealing end faces 11a and 12a may be insufficient.
However, if 0 ≦ κ ≦ 0.6 is set, the negative pressure that the back pressure acts on
Sealed regardless of the pressure fluctuation in the fluid passage 4 including the state
It is possible to properly maintain the contact pressure of the end faces 11a and 12a.
Wear. In the example shown in FIG. 2, the inner diameter D of the sealed end face 12a₁When
Outer diameter D of the end surface of the holding part where back pressure P acts₀And are the same
Therefore, κ = 0 is set.

Thus, the rotary joint R having the above structure
Therefore, in order to effectively prevent the occurrence of contamination in the mechanical seal 3 when it is mounted on the CMP apparatus, at least one of the first and second sealing rings 11 and 12 is densely carbonized according to the present invention. It is composed of a composite silicon carbide sintered body in which spherical carbon is arranged in a scattered manner in a silicon structure. When only one of the two sealing rings 11 and 12 is made of the composite silicon carbide sintered body, the other sealing ring is made of a general dense silicon carbide sintered body.

The sealing ring (first sealing ring 11 and / or second sealing ring 12) composed of such a composite silicon carbide sintered body is
For example, it is manufactured by the following sintering raw material mixing step, granulation step, preforming step, firing step, and finishing step.

[Sintering raw material mixing step] 100 α-type silicon carbide (α-SiC) powder having an average particle diameter of 0.7 μm, which is the main material
g, and boron carbide (B ₄ C) powder as a sintering aid.
5g and phenolic resin as carbon source (residual carbon ratio 5
0%) 4 g, polyethylene glycol (PEG # 6000) having an average molecular weight of 6000 as a molding aid, and stearic acid 1 g are used as a basic mixture, and spherical carbon is further added to this basic compounded material, and these are used as a methanol solvent. The materials are mixed and mixed by a ball mill for 24 hours to obtain a sintering raw material (mixed slurry). As spherical carbon,
For example, a resin obtained by heat-treating a phenol resin in a spherical shape is used. Generally, a resin having an average particle diameter of 5 to 100 μm (preferably 20 to 50 μm) having a glassy carbon composition is used. Is preferred. The carbon content in the sintering raw material (= (content of spherical carbon / content of silicon carbide) × 1
00) is 2 to 30% by weight (preferably 5 to 30% by weight).

[Granulation step] The sintering raw material obtained in the sintering raw material mixing step is spray-dried by a spray dryer to be granulated (granulated) to obtain a spherical granulated material (granule).

[Preliminary molding step] The granulation material obtained in the granulation step is filled in a predetermined die and the molding surface pressure is 1500 kg /
By cold press molding at cm ² , a preform having an annular shape corresponding to the sealing rings 11 and 12 is obtained. The shape of the preform is set in consideration of shrinkage during sintering.

[Baking Step] The preformed body obtained in the preforming step is held in an argon atmosphere at a predetermined temperature (hereinafter, referred to as “baking temperature”) for a predetermined time (hereinafter, referred to as “baking time”) without pressurization. By firing,
A composite silicon carbide sintered body having a ring shape corresponding to the sealing rings 11 and 12 is obtained. The firing conditions, particularly the firing temperature and the firing time are set so that a graphitized intermediate layer is formed between the spherical carbon and the dense silicon carbide by firing, as described later.

[Finishing step] The end surface of the composite silicon carbide sintered body obtained in the firing step is polished (lapped) to a mirror surface of Ra = 0.05, and the polished surface is hermetically sealed.
The sealed rings 11 and 12 which are a and 12a are obtained.

The sealed ring 1 obtained through these steps
When observing the structures of the lap surfaces 1 and 12 (sealed end surfaces 11a and 12a) with an optical microscope, spherical carbon X having a glassy carbon composition has a dense structure in which silicon carbide particles are bonded to each other, as shown in FIG. The silicon carbide structure Y is dispersed and arranged in a scattered manner, and an intermediate layer Z is formed at the boundary between the spherical carbon X and the surrounding silicon carbide structure Y.

The silicon carbide structure Y is densified by the bonding and self-shrinking of the silicon carbide particles by firing. On the other hand, regarding the spherical carbon X arranged in the silicon carbide structure Y, the bonding of the silicon carbide particles around the spherical carbon X,
The shrinkage behavior is uniformly received, and the physical bonding force with the silicon carbide structure Y becomes extremely large. As a result, due to the relative movement (relative rotational sliding contact) of the sealing rings 11 and 12 in the contact state, carbon silicon particles and spherical carbon X fall off,
Never leave. Therefore, the composite silicon carbide sintered body having such a structure has the same physical characteristics as the dense silicon carbide sintered body containing no solid lubricant, although it contains the spherical carbon X which is a solid lubricant ( It has mechanical strength, density, etc.). Moreover, in the sealing rings 11 and 12 made of the composite silicon carbide sintered body, due to the presence of the spherical carbon X which is the solid lubricant dispersedly arranged on the sealing end faces 11a and 12a, a dense silicon carbide firing is performed. Sliding characteristics are significantly improved as compared with a sealed ring composed of a united body.

Further, when the intermediate layer Z at the central portion and the peripheral portion of the spherical carbon X is subjected to a Raman spectrum spectroscopic analysis by a laser Raman spectroscope, as shown in FIG.
A peak due to diamond SP3 scattering near 33 cm ⁻¹ and a peak due to graphite SP2 scattering near 1590 cm ⁻¹ are conspicuous. And graphite SP2
The peak due to scattering (peak near 1590 cm ^-1 ) is
As is clear by comparing the Raman spectrum in the central portion of the spherical carbon X shown in FIG. 4A with the Raman spectrum in the intermediate layer Z shown in FIG.
It is understood that the strength of the spherical carbon X is remarkably increased, and the spherical carbon X is structurally modified and graphitized at its peripheral portion. That is, the intermediate layer Z formed on the peripheral portion of the spherical carbon X has a three-dimensional SP3 structure (diamond structure) to a two-dimensional S from an amorphous state having a strong color.
It is presumed that the P2 structure (graphite structure) was changed to an amorphous state with a strong color. In other words, it is understood that the fluctuation of the peak intensity near 1590 cm ⁻¹ in the Raman spectrum is an index indicating the structural modification (graphitization) of the intermediate layer Z.

Therefore, the sealing rings 11 and 12 made of the composite silicon carbide sintered body containing the spherical carbon X are formed on the periphery of the spherical carbon X due to the lubricity of the spherical carbon X described above. By adding the lubricity unique to graphite by the intermediate layer Z, the sealed end faces 11a, 1
The sliding characteristics of the entire 2a are significantly improved.

As described above, in the sealing rings 11 and 12 made of the composite silicon carbide sintered body containing the spherical carbon X, the spherical carbon X is formed between the spherical carbon X and the dense silicon carbide particles. The graphitized layer Z thus formed works as a solid lubricant, and can significantly reduce the friction coefficient between the sealing end faces 11a and 12a, and suppress the heat generation temperature between the sealing end faces 11a and 12a to be low (around 100 ° C.). Even under dry conditions, moisture in the air existing between the sealed end faces 11a and 12a does not evaporate, so that the sealed end faces are not seized and abnormally worn, and a low friction coefficient is stably maintained. It can be maintained without squeaking. In addition, the spherical carbon X is firmly held in the dense silicon carbide matrix Y (that is, the physical encapsulation action and the spherical force due to the contraction of the silicon carbide matrix Y during the sintering process and the spherical force X). It becomes possible to form a composite silicon carbide sintered body having a high relative density in a state where a chemical bonding action occurs between adjacent silicon carbide particles, and it is possible to prevent spherical carbon particles from falling off as much as possible. It is possible to prevent early wear and abnormal wear due to the trace holes after the falling. In addition,
In the composite silicon carbide sintered body in which the graphite particles are dispersed and arranged in the silicon carbide structure, since the graphite particles themselves have high crystallinity and poor reactivity, no chemical bond occurs with the silicon carbide particles and The minute voids present in the graphite particles impede the dense sintering, a high relative density cannot be obtained, the physical inclusion effect on the graphite particles is small, the wear progresses quickly, and the wear amount is large.

Therefore, as described above, at least one of the sealing rings 11 and 12 has the spherical carbon X dispersedly arranged in the dense silicon carbide structure Y, and the graphitized intermediate layer Z at the peripheral edge of the spherical carbon X. When the fluid 5a, 5b is liquid, of course, even when the fluid 5a, 5b is a liquid, that is, under dry conditions, noise and vibration are generated by squealing, because the composite silicon carbide sintered body is formed. The function as the mechanical seal 3 or the rotary joint R can be satisfactorily exerted by preventing abnormal wear of the sealed end faces 11a and 11b, reduction of life due to seizure, and contamination due to wear powder and falling particles.

The present invention is not limited to the above-described embodiments, and can be appropriately improved and changed without departing from the basic principle of the present invention. For example, the flow path 27,
The number of fluid passages 4 formed by 29 and the mechanical seal 3 is arbitrary, and the rotary joint R is provided with, for example, Japanese Patent Laid-Open Nos. 2001-4083 and 2001-1411.
50, a plurality of independent fluid passages 4 are disclosed.
Can be formed. When forming a plurality of fluid passages 4, a plurality of mechanical seals 3 are also provided, but the sealing rings 11, 1 in each mechanical seal 3 are provided.
Of course, at least one of 2 is composed of the above-mentioned composite silicon carbide sintered body.

[0043]

[Examples] As Example 1, the points shown in Table 1 (average particle diameter of spherical carbon in the sintering raw material mixing step, addition amount, and carbon content rate (indicated as "content rate" in Table 1))
And the same steps (sintering raw material mixing step, granulation step) as the manufacturing steps (hereinafter referred to as “standard manufacturing steps”) described in the above-described embodiment except for the baking temperature and the baking time which are the baking conditions in the baking step. , The preforming step, the firing step, and the finishing step), the first and second sealing rings 11 shown in FIG.
First sealing ring A1 to A11 and second having the same shape as 12
In addition to obtaining the sealing rings a1 to a11, as shown in Table 2, the rotary joint No. 1 having the configuration shown in FIG. 1 using these sealing rings A1 to A11 and a1 to a11. 1-No. I made 11. Each rotary joint No. 1-No. 11
The first and second sealing rings used in 1 are made of the same material, and the relative densities of the sealing rings A1 to A11 and a1 to a11 are as shown in Table 1. The first sealing ring A1
Two A11s, including those used in Example 2, were manufactured.

As Example 2, first, 100 g of β-type silicon carbide (β-SiC) powder having an average particle size of 0.6 μm was used as a main material in the sintering raw material mixing step, and spherical carbon was added to the basic compounding material. The same steps (granulation step, preforming step, firing step, finishing step) as the standard production step except that the firing conditions (firing temperature and firing time) in the firing step are set as shown in Table 1. )
Thus, a second sealing ring b1 having the same shape as the second sealing ring 12 shown in FIG. 1 was obtained. The constituent material of the second sealing ring b1 is the same as that of a general dense silicon carbide sintered body. In addition, 14 second sealing rings b1 including those used in Comparative Examples 1 to 3 described later were manufactured.

Then, as shown in Table 3, using this second sealing ring b1 and the first sealing rings A1 to A11 obtained in the first embodiment, the rotary joint No. 1 having the same construction as that of the first embodiment is used. 12-No. 22 was produced.

Further, as Comparative Example 1, as shown in Table 2 or Table 3, the second sealing ring b1 obtained in Example 2 and the first sealing ring B1 obtained in the same step as this were used, A rotary joint No. having the same configuration as that of the first and second embodiments.
23 was produced. The first sealing ring B1 has the same shape as the first sealing ring 11 shown in FIG. 1, and has a second sealing ring b1.
It is the same quality as (sintered silicon carbide compact).

Further, as Comparative Example 2, instead of spherical carbon as the solid lubricant mixed in the basic compounding material in the sintering raw material mixing step, flake graphite (average particle size, addition amount and content rate ((flake graphite content / Content of silicon carbide which is the main material) × 100) is as shown in Table 1, except that the firing temperature and firing time which are firing conditions in the firing step are set as shown in Table 1. A first sealing ring having the same shape as the first sealing ring 11 shown in FIG. 1 by the same steps as the standard manufacturing steps (sintering raw material mixing step, granulation step, preforming step, firing step, finishing step). In addition to obtaining B2, as shown in Table 3, this first sealing ring B2 and Example 2 were used.
Using the second sealing ring b1 obtained in No. 2, the rotary joint No. 1 having the same structure as in Examples 1 and 2 or Comparative Example 1.
24 were manufactured.

Further, as Comparative Example 3, except that the particle size, addition amount, and content rate of the flake graphite are as shown in Table 1,
Same as Comparative Example 2 except that the first sealing ring B3 of the same shape was obtained by the same process as the first sealing ring B2 of Comparative Example 2 and the first sealing ring B3 was used as shown in Table 3. The rotary joint No. I made 25.

By the way, as shown in Table 1, the relative densities of the sealing rings A1 to A11 (a1 to a11) using spherical carbon as the solid lubricant are as shown in Table 1 in the sealing rings B2 and B3 using the flake graphite as the solid lubricant. The value is extremely high in comparison with the relative densities of the sealing rings B1 and b1 made of a dense silicon carbide sintered body that does not contain a solid lubricant. It is understood that when is a spherical body (spherical carbon) having a carbon composition (glassy carbon composition), a fully compacted high density and high strength sintered body can be obtained as a whole.

Further, the wrap surface (sealing end surface) of each sealing ring A1 to A11 (a1 to a11) containing spherical carbon.
Was subjected to image processing using an optical microscope and the thickness of the intermediate layer (graphitized layer) formed on the peripheral portion of the spherical carbon was measured. As shown in Table 1, all were 1 μm or more, and the firing temperature was high. It was found that the longer the firing time or the firing time, the greater the thickness of the intermediate layer. From this, it is understood that the growth of the intermediate layer is promoted as the firing temperature or the firing time is increased within the predetermined range. Also, each sealing ring A
1-A11 (a1 to a11), the surface texture on the lap surface was observed with an optical microscope. As a result, no gap was observed at the boundary between the silicon carbide texture and the spherical carbon, indicating that the two were closely bonded. confirmed. Further, no portion where spherical carbon was dropped from the silicon carbide structure was not recognized at all, and it was observed that the spherical carbon was broken along the silicon carbide grains. This is because the spherical carbon becomes a dense silicon carbide due to the physical inclusion effect due to the contraction of the silicon carbide matrix in the sintering process and the chemical bonding effect generated between the spherical carbon and the surrounding silicon carbide. It is understood that this is because the spherical carbon particles are firmly held in the matrix, so that it is possible to prevent the spherical carbon particles from falling off and prevent early wear and abnormal wear due to the trace holes after the fall.

[0051]

[Table 1]

Thus, the rotary joint No. 1 of the first embodiment is used. 1-No. 11 and the rotary joint No. 1 of Comparative Example 1. 23, the following seal test (hereinafter referred to as “first seal test”) was performed.

That is, in the first seal test, water is passed for 10 seconds (the fluid passage 4 under the atmospheric pressure condition) while the rotating body 2 is stopped (the joint body 1 is in a fixed normal state).
To the fluid passage 4), and then continuously aerate for 10 seconds (aeration by continuously supplying compressed air of 0.3 MPa to the fluid passage 4) with the rotor 2 stopped. While maintaining the state, rotate the rotor 2 to 5
It was rotated for 80 seconds (rotation speed: 150 min ⁻¹ ), and the steps 1 to 5 were repeated for 5 cycles (50 minutes) as one cycle (10 minutes). Then, the friction coefficient (torque) of the sliding surface (sealing end surface) of the mechanical seal 3 and the temperature in the vicinity of the sliding surface (hereinafter referred to as "sliding surface temperature") were measured. As a result, the rotary joint No. 1 of the first embodiment is shown. No. 1 is as shown in FIG. 5 (the friction coefficient is shown by a solid line and the sliding surface temperature is shown by a broken line). No. 23 was as shown in FIG. 7 (the friction coefficient is shown by a solid line and the sliding surface temperature is shown by a broken line). FIG. 5 shows the rotary joint No. 1 shows the friction coefficient and the sliding surface temperature for No. 1, but other rotary joints N
o. 2 to No. Also for No. 11, the friction coefficient, the value of the sliding surface temperature and the variation pattern thereof which are substantially the same as those in FIG. Therefore, FIG. 5 shows these rotary joint Nos. Two
~ No. This can be regarded as the result of the 11th first seal test. The friction coefficients shown in FIGS. 5 and 7 are not directly measured, but torques are measured and the values are converted into friction coefficients.

As is apparent from FIG. 5, the rotary joint No. 1 according to the present invention is shown. 1-No. In 11,
Even in the initial stage of rotation of the rotating body 2, almost no increase in the friction coefficient and the temperature of the sliding surface was observed, and it was understood that the friction coefficient and the temperature of the sliding surface were substantially constant and a stable mechanical sealing function was exhibited. It On the other hand, the rotary joint No. 1 of Comparative Example 1 using both sealing rings B1 and b1 made of a general dense silicon carbide sintered body. In No. 23, as shown in FIG. 7, the friction coefficient sharply increases in the initial stage of rotation, and the initial torque is extremely high. Also, the sealing ring B1,
The friction coefficient is reduced due to the repeated rotation of b1, but this is a result of the contact surface (sealing end surface) of the sealing ring B1, b1 being worn by rotation and accustomed to it, which causes contamination. (This is also confirmed from the profile of the sliding surface described later).

Further, it was confirmed in the first seal test that squeal was generated. 1-No. 1
As shown in Table 2, no squeal was generated in any of Nos. 1 and 5 in the steps. From this, the rotary joint No. 1-No. It is understood that the CMP apparatus using No. 11 operates silently without noise (squeaking). On the other hand, the rotary joint No. 1 of the first comparative example. Regarding No. 23, a clear squeaking occurred in the initial stage of rotation. In Table 2, the case where no squeaking occurred was indicated by "◯", and the case where even slight squeaking occurred was indicated by "x".

After completion of the first seal test, the rotary joint No. The sealing rings A1, a1 were removed from No. 1 and their sliding surfaces were profiled. As a result, as shown in FIG. 6, no wear scratches (annular marks, etc., which will be described later) were found on the sliding surfaces of any of the sealing rings A1 and a1,
It was confirmed that the same profile as before the seal test was maintained. Further, as shown in Table 2, generation of abrasion powder was not recognized at all. These are the same as other rotary joint Nos. 2 to No. The same applies to 11. On the other hand, the rotary joint No. 1 of Comparative Example 1 was used. Two
In Fig. 3, wear scratches were recognized on the sliding surface after the first seal test as shown in Fig. 8, and particularly on the sliding surface of the first sealing ring B1, as shown in Fig. 8 (a), a remarkable annular shape was observed. Scratch (record groove-shaped annular groove, depth δ was 4 μm)
Was recognized. In addition, the rotary joint No. In No. 23, as shown in Table 2, generation of abrasion powder was also recognized. In Table 2, “A” indicates that no abrasion powder was generated, and “X” indicates that abrasion powder was generated.

[0057]

[Table 2]

Results of the above first seal test (FIGS. 5-8)
As is clear from Table 2) and the rotary joint No. 1 according to the present invention. 1-No. According to No. 11, the rotary joint No. 1 using the seal rings B1 and b1 made of a general dense silicon carbide sintered body. It is understood that compared to No. 23, the fluid transport between the relative rotating members in the CMP apparatus can be performed satisfactorily and quietly without causing contamination.

Further, the rotary joint N of the second embodiment
o. 12-No. 22 and the rotary joint No. of the comparative example. 23-No. 25, the following seal test (hereinafter referred to as “second seal test”) was performed.

That is, in the second seal test, the load pressure of the mechanical seal 3 is 0.1 MPa and the peripheral speed is 2 m.
By continuously operating for 2 hours under a dry condition of / s, the wear amount of the sliding surface (sealed end surface), the friction coefficient, and the sliding surface temperature were obtained, and the occurrence of squeaking and the sliding surface state were confirmed. .
The results are as shown in Table 3. In Table 3, those that did not generate squeaking were indicated by “◯”, and those that generated squeaking were indicated by “x”. The sliding surface condition was determined by removing the sealing ring after the completion of the second seal test and visually observing the degree of generation of annular marks and abrasion powder on the sliding surface. Regarding the annular mark, in Table 3, those marked with an annular mark (recording groove-shaped annular groove) were marked with “x”, and those marked with no annular mark were visually observed. "○" is attached. In addition, regarding abrasion powder, in Table 3, those in which a large amount of abrasion powder was generated are marked with “x”, and those in which abrasion powder was generated slightly are marked with “△”, and abrasion powder was generated at all. Those not done are marked with "○".

[0061]

[Table 3]

As is clear from the results of the second seal test shown in Table 3, the rotary joint No. 1 of Example 2 was used. 12
~ No. 22, in any of them, Comparative Examples 1 to 3
Rotary joint No. 23-No. It is understood that the friction coefficient is much lower than that of No. 25, no squeaking occurs, the sliding surface temperature (heat generation) is suppressed, and the wear is significantly reduced. This is mainly due to the fact that the slidability of the sealing ring is greatly improved by the spherical carbon and the graphitized intermediate layer functioning as a solid lubricant. By the way, the rotary joint No. 1 of Example 1 in which both sealing rings are made of a composite silicon carbide sintered body having spherical carbon and an intermediate layer. 1-No. When the second seal test was performed on No. 11, the rotary joint No. 1 of Example 2 in which only one seal ring (first seal ring) was formed of the composite silicon carbide sintered body. 12-No. Needless to say, a better result than that of No. 22 can be obtained.

[0063]

As can be understood from the above description, according to the rotary joint for a CMP device of the present invention, it is possible to effectively prevent the occurrence of fluid contamination or squeal due to the relative rotational sliding contact of the sealing ring. As a result, fluid transportation between the relative rotating members of the CMP apparatus can be favorably performed for a long period of time without causing leakage. Such an effect is more remarkably exhibited especially when both sealing rings of the mechanical seal are made of the above-mentioned composite silicon carbide sintered body.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of a rotary joint according to the present invention.

FIG. 2 is an enlarged detailed view of a main part of FIG.

FIG. 3 is a structural diagram of a lap surface (sealing end face) of a sealing ring of the rotary joint, which is made of a composite silicon carbide sintered body.

FIG. 4 is a Raman spectrum of the sealed end face,
(A) figure shows the Raman spectrum in the central part of spherical carbon, and (b) figure has shown the Raman spectrum in the middle class which is the peripheral part of the spherical carbon concerned.

FIG. 5 is a first example in which the rotary joint of Example 1 is used.
It is a curve figure which shows the time-dependent change of the friction coefficient and sliding surface temperature in a seal test.

FIG. 6 is a profile view of the sealing ring sliding surface after the completion of the first seal test in the rotary joint of Example 1, FIG. 6A shows the sliding surface profile of the first sealing ring, and FIG. The figure shows the profile of the sliding surface of the second sealing ring.

FIG. 7 shows a first example in which the rotary joint of Comparative Example 1 is used.
It is a curve figure which shows the time-dependent change of the friction coefficient and sliding surface temperature in a seal test.

8 is a profile view of the sealing ring sliding surface after the completion of the first seal test in the rotary joint of Comparative Example 1, FIG. 8 (a) shows a profile of the sliding surface of the first sealing ring, and FIG. The figure shows the profile of the sliding surface of the second sealing ring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Joint main body, 2 ... Rotating body, 3 ... Mechanical seal, 4 ... Fluid passage, 11 ... 1st sealing ring, 11a, 12a
... Sealing end face, 12 ... Second sealing ring, 27 ... First flow path (flow path formed in rotating body), 29 ... Second flow path (flow path formed in joint body), R ... Rotary joint, X ...
Spherical carbon, Y ... Silicon carbide structure, Z ... Intermediate layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 35/56 101Y (72) Inventor Risa Suzuki 1 at 529 Shibatai Shinji Hitoba, Mita City, Hyogo Prefecture Japan Pillar Industry Co., Ltd. M-term F-term (reference) 3C047 FF08 FF17 GG20 3C058 AA07 AC01 CB06 DA17 3H104 JA04 JB04 JC08 JC10 JD09 LF10 3J041 AA03 BA04 BB01 BC02 BD06 4G001 BA22 BA60 BB22 BB60 BD11 BD13 BD38 BE38 BD38

Claims (7)

[Claims] 1. A first sealing ring made of silicon carbide, which is provided in a rotating body, and a flow path formed in a rotating body, which is rotatably connected to the joint body At least one of the first and second sealing rings is provided in a rotary joint which is connected to form a series of fluid passages by an end-face contact type mechanical seal configured with the provided second sealing ring made of silicon carbide. One of them is composed of a composite silicon carbide sintered body in which spherical carbon having an average particle diameter of 5 to 100 μm is arranged in a dense silicon carbide structure in a scattered state at a ratio of 2 to 30% by weight with respect to silicon carbide. A characteristic rotary joint for CMP equipment. 2. The rotary joint for a CMP apparatus according to claim 1, wherein both the first and second sealing rings are made of the composite silicon carbide sintered body. 3. The spherical carbon has an average particle size of 20 to 50.
μm and the content of silicon carbide is 5
The rotary joint for a CMP apparatus according to claim 1 or 2, wherein the content is about 20% by weight. 4. The composite silicon carbide sintered body, wherein a graphitized intermediate layer is formed between each spherical carbon and a surrounding silicon carbide structure. The rotary joint for a CMP apparatus according to claim 1, claim 2 or claim 3. 5. The Raman shift 1590c is provided in the intermediate layer.
5. The rotary joint for a CMP device according to claim 4, wherein the Raman spectrum intensity indicating SP2 scattering of graphite is higher in the vicinity of m ⁻¹ than the intensity in the central portion of the spherical carbon. 6. The rotary joint for a CMP apparatus according to claim 4, wherein the thickness of the intermediate layer is at least 1 μm. 7. The rotary joint for a CMP apparatus according to claim 6, wherein the intermediate layer has a thickness of 4 to 10 μm.