JP3005643B2 - Rotary joint for fluid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CMP (Chemic) for performing wafer polishing in a semiconductor manufacturing process.
More specifically, the present invention relates to a fluid rotary joint used in an al-mechanical polishing device and the like, and more specifically, to make a sealing device for a fluid such as a polishing liquid in a rotating portion excellent in durability while obtaining a reliable sealing function. About technology.

[0002]

2. Description of the Related Art A conventional rotary joint for fluid is disclosed in Japanese Patent Application Laid-Open No. 7-98085 (see FIGS. 1 and 2).
Also, as shown in FIG. 11 of U.S. Pat. No. 5,443,416, a seal mechanism formed between a fixed joint and a rotary joint has a pair of O-rings sandwiching a fluid path extending therebetween. And lip seals.

[0003]

A sealing mechanism using an O-ring or a lip seal has a simple structure and requires a relatively small space for arrangement, but is often used, but has a low PV load capability. Therefore, the life is 1-2
They tend to be as short as about a month, requiring frequent replacement of parts, leaving room for improvement. In particular, a rotary joint through which a slurry (polishing liquid) in which a liquid such as a chemical agent and particles are mixed for use in polishing is used, the sealing life is further disadvantageous. An object of the present invention is to provide a fluid rotary joint having a long life and excellent reliability by reviewing a sealing mechanism.

[0004]

According to a first aspect of the present invention, there is provided a fluid rotary joint for use in a chemical mechanical polishing apparatus, wherein the fluid rotary joint has a polishing liquid passage through which a polishing liquid passes and an air passage through which pressurized air passes. Are provided with a first joint body and a second joint body, each of which is formed to penetrate therethrough, and the second joint body is relatively rotatably fitted inside the first joint body, and each polishing liquid path of both joint bodies is connected to the rotation axis. On the other hand, the air paths of the two joint bodies are communicated with each other via the seal mechanism between the inner peripheral surface of the first joint body and the outer peripheral surface of the second joint body, while being communicated with each other via the seal mechanism. A seal member that is not rotatable relative to one joint body and is relatively movable in the direction of the rotational axis, and the seal member is connected to the other joint body. And forming each by a mechanical seal mechanism and a biasing mechanism for pressing urged toward the seal receiving portion provided in Preparative body, on which seals the polishing liquid path
While a winding spring is used as a biasing mechanism of the seal mechanism,
A disc spring is used as a biasing mechanism of the seal mechanism for sealing the air path. The rotary joint for fluid according to claim 2 is a rotary joint for fluid according to claim 1, which is used in an apparatus for performing wafer polishing in a semiconductor manufacturing process, wherein a periphery of a seal mechanism that seals the polishing liquid path, A cooling liquid circulation area for cooling the seal mechanism is provided.

According to the first aspect of the present invention, the polishing liquid path is closed.
Since the sealing mechanism that performs sealing is a mechanical seal structure, it is easy for the urging mechanism to bring the sealing member and the seal receiving portion into contact with each other with a high pressure. In addition, an effective sealing function can be exhibited. In addition, since the seal member is urged by the urging mechanism, it can be used even if the seal contact part is worn out somewhat, and if it is worn out, the parts need to be replaced. This is also advantageous in terms of durability.

[0007] Since the seal member can be moved relative to the first joint body in the direction of the rotation axis, a seal mechanism that straddles both of them is required. However, these two members do not rotate relative to each other, and Actually, the movement in the direction of the rotation axis is almost the same, so that only the provision of a conventional sealing mechanism such as an O-ring can secure sufficient sealing performance and durability. The effect can be obtained without inconvenience.

According to the second aspect of the present invention, the polishing liquid path is closed.
Since the cooling liquid circulation area for cooling the sealing mechanism for cooling from outside is provided, frictional heat caused by the sealing member and the seal receiving portion being pressed and in rotational contact can be removed by the cooling liquid, and the Roughness of the sealing surface and a decrease in the sealing function due to the roughening can be prevented, and the durability of the sealing mechanism can be made sufficient.

[0009]

[Effect of the Invention] The fluid rotary joint according to claim 1, 2, main sealing mechanism between a pair of joint members
With Kanikaru seal structure, it is possible to exhibit a good sealing function well tolerated even at high fluid pressure,
It was possible to obtain excellent durability and reliability capable of exhibiting the good sealing performance over a long period of time. Also, the above row
The tally joint has a polishing liquid path and a pressurized liquid
An air path for passing air is formed, and a polishing liquid path is formed.
Or, compared to the conventional air path,
The structure as a device can be simplified and compact
It is also possible.

In the rotary joint for fluid according to the second aspect, the liquid cooling structure of the seal mechanism has an advantage that the above-mentioned effect can be more excellently and surely obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 and FIG.
A model of a CMP apparatus for performing the surface polishing of No. 09 is shown. The CMP apparatus includes a rotary table 102 that is driven and rotated around a vertical rotation axis P, a pad support 103 that moves horizontally (reciprocates), and a polishing pad that is driven and rotated while being supported by the pad support 103. 104, a supply / discharge path 105 formed in the pad support 103, a supply / discharge mechanism 107 for the polishing liquid 106 connected to the supply / discharge path 105,
The polishing pad 104 is provided with a supply / discharge path 108 formed in the polishing pad 104 so as to penetrate the rotation axis P and open downward at the center of the pad portion 104a at the lower end. In addition, polishing liquid 1
As an example of 06, isopropyl alcohol is added to a silica slurry containing KOH as an alkaline component.

Further, in order to blow down the pressurized air from the pressurizing device 6 such as an air pump from the pad portion 104a,
The air passages 105 a and 108 a formed in the pad support 103 and the polishing pad 104 are configured to pass therethrough. In order to support the polishing pad 104 on the pad support 103 so as to be rotatable around the vertical rotation axis Q, the polishing pad 104 is interposed between the two, 104 and 103, and
Both supply and discharge paths 105 and 108 and both air paths 105a,
A rotary joint 101 is provided for connecting each of the motors 108a so as to be relatively rotatable.

According to this CMP apparatus, first, the silicon wafer 109 is placed and held on the rotary table 102 so that the wafer surface 109a is on the top, and then the polishing pad 1
04, the pad portion 104a at the lower end is
Lower until it contacts 9a. Next, the supply / discharge mechanism 107
Of the polishing liquid (slurry) 10 between the pad portion 104a and the wafer 109 by the positive pressure operation (discharge operation of the polishing pump).
6 and the pressurized air 106a,
The wafer surface 109a is polished by reciprocating forward and backward while rotating the wafer 04.

The pad portion 104a has a pressurized air 106a.
Are formed. A plurality of air paths 108a for ejecting the polishing liquid are formed, and the polishing liquid 106 ejected between the pad portion 104a and the wafer 109 is quickly and uniformly dispersed by the pressurized air 106a ejected from the air paths 108a . At the same time, the polishing residual liquid can be quickly removed from between the both 104a and 109. After the polishing is completed, the supply / discharge mechanism 107 is switched to a negative pressure operation (a suction operation of the polishing pump), and the polishing liquid 106 remaining in the supply / discharge paths 105 and 108 is suctioned and discharged so as not to drop on the wafer surface 109a. It is.

Next, the rotary joint 101 will be described. As shown in FIG. 1, a fixed-side first joint body 1 attached to the pad support 103, a rotating-side second joint body 2 attached to the polishing pad 104,
The first to third seal mechanisms 3, 4 and 5 interposed between the two joint bodies 1 and 2, the polishing liquid path A and the air path B extending over the two joint bodies 1 and 2, etc.
01.

The first joint body 1 includes upper and lower cylindrical portions 10
a, 10c, and a cylindrical side walls 10 of made of intermediate cylinder 10b interposed between the cylindrical portion 10 a, 10c, is composed of a disc-shaped end wall 11 Prefecture, side walls 10 is
It is formed of a metal material such as stainless steel (SUS304). Since the fluid passages 60 through which the polishing liquid 106 flows are formed in the end wall 11, PEEK (excellent in dimensional stability and heat resistance by processing without generating particles due to contact of abrasive grains) is provided. PES or PC may be used)
And other plastics for mechanical parts.

The second joint body 2 has a cylindrical main body 2.
0, a holding portion 21 formed at an upper end thereof, a disk-shaped flange portion 22 formed at a lower end of the main body 20,
The main body 20 includes a cylindrical lid 23 that is externally fitted to the main body 20, and portions other than the lid 23 are integrally formed.
Since the fluid passage 61 through which the polishing liquid 106 flows is formed in the second joint body 2, like the end wall 11, portions other than the lid 23 are formed of a plastic for mechanical parts such as PEEK. The lid 23 is made of a metal material such as stainless steel.

The second joint body 2 is rotatably fitted in the first joint body 1 by interposing a bearing 13 between the lower end of the end wall 11 and the lower end of the lid 23. Only 23 is configured to be exposed from the first joint body 1 to the outside.

The first seal mechanism 3 includes a first joint body 1
A seal member 31 which is not rotatable relative thereto and is relatively movable in the direction of the rotation axis Q;
A seal receiving portion 30 provided on the second joint body 2 in a state where the seal receiving portion 30 can be brought into contact with the second joint body 2 while being relatively rotated with respect to
Mechanism 3 for stopping the rotation of the first joint body 1 with respect to the first joint body 1
2 and an urging mechanism 33 for urging the seal member 31 toward the seal receiving portion 30.

The seal receiving portion 30 includes the second joint body 2
Made of silicon carbide including a main body portion 30 b fitted inside the holding portion 21 and a tapered seal action portion 30 a, and the upper surface of the seal action portion 30 a is suitable for contact with the seal member 31. It has a smooth sealing surface 30c. Body 3
0 b a fitting portion between the holding portion 21 is a secondary sealed by O-ring 24. Inside the seal receiving portion 30,
The fluid passage 30d communicating with the fluid passage 61 has the rotational axis Q
Is formed on.

The seal member 31 has an annular main body 31a.
And a cylindrical holding portion 31b having a smaller diameter than the holding portion 31b. It is slidably supported. The holding hole 11a and the holding portion 31b are secondarily sealed with an O-ring 14. The bottom surface of the main body 31a is formed as a smooth contact surface 31c so as to make surface contact with the seal surface 30c of the seal receiving portion 30. A fluid passage 3 a communicating with the fluid passage 60 is formed on the rotation axis Q inside the seal member 31.

The locking mechanism 32 is configured to protrude from the bottom surface of the end wall 11 which is a peripheral region of the holding hole 11a of the locking pin 32a downwardly, sealing the engaging recess 32b of the locking pin 32a enters The sealing member 31 is formed on the main body 31a of the member 31, and the sealing member 31 is moved in the direction of the rotation axis Q with respect to the first joint body 1 by engaging the locking pin 32a with the engaging recess 32b. And, and
Relative rotation is disabled.

The biasing mechanism 33 includes a plurality of winding springs 33a interposed between the upper end of the main body 31a of the seal member 31 and the lower end of the end wall 11 opposed thereto. , The sealing member 31 is urged downward to
This is to make a zero-contact.

With the above structure, the first seal mechanism 3 exhibits the same sealing performance as the mechanical seal of the end face contact type, and the inside of the seal face 30c and the contact face 31c accompanying the rotation of the second joint body 2. The space between the region 3a and the outer region (an example of the outside of the seal member) 3b is sealed well. The dimensions of each part are set such that the good sealing function is maintained even when the polishing liquid path A is switched to the negative pressure or the dry mode.

The second and third seal mechanisms 4 and 5 shown in FIGS. 1 to 3 have basically the same structure, and the lid 23 which is the outer peripheral portion of the second joint body 2 and the first joint body 1 have the same structure. It is provided in parallel with the intermediate cylinder 10b along the rotation axis Q direction. The second sealing mechanism 4 includes a side wall 10 and a lid 2.
3 is an end face contact type mechanical seal interposed between
Since the lower end of the outer region 3b of the first seal mechanism 3 is sealed, the outer region 3b is thereby configured as a cooling liquid path described later. The third sealing mechanism 5 seals the air path B. Next, the structure of the second seal mechanism 4 will be described. The reference numerals in parentheses indicate those of the third seal mechanism 5.

As shown in FIGS. 1 to 3, a stationary ring 43 (53) as a seal receiving portion fixedly held inside the side wall 10 via an O-ring 42 (52) through an O-ring 42, Lid 2
3, a rotary seal ring 45 as a seal member held movably in the direction of the rotational axis Q via an O-ring 44 (54).
And (55), a spring retainer 46 fixed to the lid 23, and a disc spring 47 (57), the stationary ring 43 (5
3) and the rotary seal ring 45 (55), by the relative rotational sliding action, seals the outer region 4a of the second and third seal mechanisms 4, 5 with the coolant path 3b, and seals the lower end of the outer region 4a. And do.

The rotary seal ring 45 (55) has an engaging groove 45a (55a) formed on its outer periphery engaged with an engaging projection 46a of the spring retainer 46, so that the rotary seal ring 45 (55) can freely rotate in the direction of the rotation axis Q. And it is held by the second joint body 2 so as not to rotate relatively. Thus, the side wall of the first joint body 1
From the supply hole 11b drilled in the 10, the cooling water supplied is discharged from the water cooling system 15 by the water pump or the like (an example of a cooling liquid) 8, cooling fluid path formed in the outer region 3b (the coolant circulation region Example) Through C, the gas is discharged from a discharge hole (not shown, which is the same as the supply hole 11b provided on the opposite side), and the first seal mechanism 3 can be cooled from the outside. .

The compressed air 10 from the pressurizing device 6
6a can be ejected downward from the flange portion 22 through the air path B including the passage 70, the outer region 4a, the opening passage 71d, the annular passage 71a, the communication passage 71c, and the annular passage 71b of the intermediate cylinder 10b. . The polishing liquid 106 from the supply / discharge mechanism 107 is ejected downward from the flange portion 22 through the polishing liquid path A including the fluid passage 60, the fluid passage 3a, the fluid passage 30d, and the fluid passage 61. Can be.

As described above, the rotary joint 101 has a polishing liquid path A through which the polishing liquid 106 passes, an air path B through which pressurized air passes, and a cooling liquid path C through which the cooling water of the first seal mechanism 3 passes. Three paths are formed, and the structure as a CMP apparatus can be simplified as compared with the conventional case where the polishing liquid path A or the air path B is separately provided.
Compactness is also possible.

The rotary joint 101 having no coolant path C for the first seal mechanism 3 may be used.
The rotary joint 101 may have a structure in which the joint body 1 is on the rotating side and the second joint body 2 is on the fixed side.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a rotary joint.

FIG. 2 is an enlarged sectional view showing a structure of a first seal mechanism.

FIG. 3 is an enlarged cross-sectional view showing a structure of a second and third seal mechanisms.

FIG. 4 is a principle view schematically showing a CMP apparatus.

FIG. 5 is an operation diagram showing a state in which a polishing liquid and pressurized air are supplied to a wafer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st joint body 2 2nd joint body 3 1st seal mechanism 3a, 30d Fluid passage 30 Seal receiving part 31 Seal member 33 Urging mechanism 60, 61 Fluid passage C Coolant path Q Rotation axis

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16L 27/08

Claims (2)

(57) [Claims] 1. A fluid rotary joint for use in a chemical mechanical polishing apparatus, wherein a first joint body and a second joint each having a polishing liquid path for passing a polishing liquid and an air path for passing pressurized air formed therethrough. And a second joint body is fitted inside the first joint body so as to be relatively rotatable, and the polishing liquid paths of both joint bodies are communicated with each other via a seal mechanism on a rotation axis. First air path of joint body
The inner peripheral surface of the joint body and the outer peripheral surface of the second joint body are communicated with each other via a seal mechanism, and each of the seal mechanisms is not rotatable relative to one of the joint bodies in the rotational axis direction. Are formed by a mechanical seal mechanism having a relatively movable seal member and an urging mechanism for urging the seal member toward a seal receiving portion provided on the other joint body, and seal the polishing liquid path. As an urging mechanism for the above seal mechanism
A rotary joint for fluid, wherein a disc spring is used as an urging mechanism of a sealing mechanism for sealing an air path while using a spiral spring. 2. The fluid rotary joint according to claim 1, which is used in an apparatus for performing wafer polishing in a semiconductor manufacturing process, wherein said fluid rotary joint is provided around said seal mechanism for sealing said polishing liquid path. A rotary joint for fluid, characterized by comprising a cooling liquid circulation region of (1).