Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C29/00—Bearings for parts moving only linearly
  • F16C29/02—Sliding-contact bearings
  • F16C29/025—Hydrostatic or aerostatic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/0009—Energy-transferring means or control lines for movable machine parts; Control panels or boxes; Control parts
  • B23Q1/0018—Energy-transferring means or control lines for movable machine parts; Control panels or boxes; Control parts comprising hydraulic means
  • B23Q1/0027—Energy-transferring means or control lines for movable machine parts; Control panels or boxes; Control parts comprising hydraulic means between moving parts between which an uninterrupted energy-transfer connection is maintained
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/25—Movable or adjustable work or tool supports
  • B23Q1/26—Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members
  • B23Q1/38—Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable members; Means for preventing relative movement of such members using fluid bearings or fluid cushion supports
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
  • F16C32/0603—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion
  • F16C32/0614—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a gas cushion, e.g. an air cushion the gas being supplied under pressure, e.g. aerostatic bearings
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
  • G03F7/70808—Construction details, e.g. housing, load-lock, seals or windows for passing light in or out of apparatus
  • G03F7/70816—Bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2300/00—Application independent of particular apparatuses
  • F16C2300/40—Application independent of particular apparatuses related to environment, i.e. operating conditions
  • F16C2300/62—Application independent of particular apparatuses related to environment, i.e. operating conditions low pressure, e.g. elements operating under vacuum conditions
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2322/00—Apparatus used in shaping articles
  • F16C2322/39—General build up of machine tools, e.g. spindles, slides, actuators

Definitions

• the present invention relates to a static pressure air bearing having two axes, a lower axis and an upper axis, used in a vacuum environment.
• the conventional air exhaust method requires, with respect to the upper axis, the connection of the air exhaust pipe with the movable part of the upper axis bearing mechanism. Additionally, a large bore diameter of the pipe is required to obtain efficient air exhaust displacement. These features cause a great resistance to the feeding motion of the bearing and seriously affect the bearing performance. This problem arises when the air exhaust pipe is connected with the movable part of the upper axis, and also arises when the air exhaust pipe is connected with inner piping formed within a fixed part of the upper axis (because the fixed part of the upper axis also moves).
• the present invention provides a static pressure air bearing having two axes usable in a vacuum environment in which the connection of the supporting air exhaust pipe does not adversely affect the motion of the bearing mechanism.
• a static pressure air bearing having two axes, a lower axis and an upper axis, in which inner air exhaust piping formed within a fixed part of the lower axis and inner air exhaust piping formed within a fixed part of the upper axis (which is fixed on a movable part of the lower axis) communicate with each other.
• the air exhaust pipe can be connected only with the fixed part of the lower axis and need not be directly connected with the movable parts of the bearing mechanism. Consequently, an air exhaust pipe of a large bore diameter does not adversely affect the bearing performance.
• the communication between the inner air exhaust piping of the fixed part of the lower axis and the inner air exhaust piping of the fixed part of the upper axis is provided through air exhaust communication grooves and air exhaust communication piping formed within the movable part of the lower axis.
• the supporting air is exhausted through the inner air exhaust piping formed within the fixed parts of the lower and upper axes.
• the air exhaust pipe need not be connected either with the movable part of the lower axis or with the movable part of the upper axis.
• air exhaust grooves are disposed surrounding each air pad of the lower and upper axes.
• air supply structure is also accommodated in the fixed parts. That is, inner air supply piping formed within the fixed part of the lower axis and inner air supply piping formed within the fixed part of the upper axis (which is attached to the movable part of the lower axis) communicate with each other.
• Fig. 1 is a perspective view showing an embodiment of a static pressure bearing mechanism according to the present invention
• Fig. 2 is a sectional view of part of the static pressure air bearing mechanism shown in Fig. 1;
• Fig. 2(a) is a sectional view of the Fig. 1 static pressure air bearing mechanism
• Fig. 2(b) is a sectional view like Fig. 2(a), but shows the movable part of the upper axis moved to its left-most position
• Fig. 2(c) is a plan view of the surface of the fixed part of the upper axis, as seen in the direction of arrow C in Fig. 2(b);
• Fig. 2(d) is a sectional view of the upper axis as seen in the direction of arrow D in Fig. 2(b);
• Fig. 2(e) is a sectional view of the upper axis as seen in the direction of arrow E in Fig. 2(b);
• Fig. 2(f) is a sectional view like Fig. 2(a);
• Fig. 2(g) shows the upper surfaces of lower axis fixed parts as seen in the direction of arrow G in Fig. 2(f);
• Fig. 2(h) is a plan view of the inner surface of the lower axis movable parts as seen in the direction of arrow H in Fig. 2(f);
• Fig. 2(i) is a sectional view like Fig. 2(a);
• Fig. 2(j) is a sectional view of the lower axis as seen in the direction of arrow J in Fig. 2(i);
• Fig. 2(k) is a sectional view like Fig. 2(a);
• Fig. 2(1) is a sectional view of the lower axis as seen in the direction of arrow L in Fig. 2(k);
• Fig. 3 is a cross-sectional view as seen in the direction of arrow A in Fig. 2(a) of the fixed and movable parts of the upper axis;
• Fig. 4 is a plan view of the inner surface of the upper axis movable part as seen in the direction of arrow B in Fig. 2(b);
• Figs. 5(a) and 5(b) are see-through views that show the relative positions of the exhaust grooves, air pads and exhaust apertures of the fixed and movable parts of the respective upper and lower axes when the movable parts are at opposite ends of their respective ranges of movement;
• Figs. 5(c), 5(d) and 5(e) show the relative positions between the elements (the air pads and exhaust apertures) on the upper axis fixed part and the corresponding elements (the exhaust grooves) on the upper axis movable part in an alternative embodiment having two grooves, when the movable part is located at a central position (Fig. 5(c)), a left-most position (Fig. 5(d)) and a right-most position (Fig. 5(e));
• Fig. 6(a) is a sectional view of a static pressure air bearing mechanism according to an alternative embodiment in which the air pads are provided on the upper and lower axes movable parts;
• Fig. 6(b) is a plan view of the inner surface of the upper axis movable part as seen in the direction of arrow Bl in Fig. 6(a);
• Fig. 6(c) is a plan view of the upper surface of the upper axis fixed part as seen in the direction of arrow CI in Fig. 6(a);
• Fig. 7(a) is a sectional view of a static pressure air bearing mechanism having a different air pad architecture from the Fig. 6(a) embodiment;
• Fig. 7(b) is a plan view of the inner surface of the upper axis movable part as seen in the direction of arrow B2 in Fig. 7(a);
• Fig. 7(c) is a plan view of the upper surface of the upper axis fixed part as seen in the direction of arrow C2 in Fig. 7(c).
• the disclosed static pressure air bearing can be used in various precision engineering applications where it is desirable to precisely position a workpiece.
• the workpiece can be, for example, a part to be machined and/or inspected or a substrate such as a silicon wafer or glass (or quartz) panel on which circuitry is to be formed and/or inspected.
• the disclosed static pressure air bearing can be used to support a substrate in a photolithography apparatus.
• the movable part of the upper axis would typically include a wafer stage and/or chucking apparatus to hold the substrate.
• Fig. 1 is a perspective view showing an embodiment of a static pressure bearing mechanism according to the present invention.
• Figs. 2, 2(a), 2(b), 2(f), 2(i) and 2(k) are sectional views showing the junction of the movable part of the lower axis and the fixed part of the upper axis of the static pressure bearing mechanism of
• air supply tubes 2 and air exhaust pipes 3 are connected with lower axis fixed parts 4.
• the supporting air that is supplied by the air supply tubes 2 flows through inner air supply pipes (passages) 5 formed within the lower axis fixed parts 4, through air passages 6, and ultimately is supplied to each of air pads 7 to float lower axis movable parts 1.
• the inner air supply pipes can be seen in Fig. 2(1).
• the supporting air supplied to each of the air pads 7 of the lower axis subsequently flows between the fixed parts 4 and the movable parts 1 and into air exhaust grooves 8 formed in the inner surface of the movable parts 1, which extend around the air pads 7 (see Fig. 2(h)).
• the air After entering the exhaust grooves 8, the air passes through inner air exhaust pipes (passages) 9 by way of air exhaust tunnels (passages) 20 formed within the lower axis fixed parts 4, and ultimately is exhausted (via exhaust pipes 3) outside of the vacuum chamber.
• the inner air exhaust pipes can be seen in Fig. 2(j).
• the air passages 6 within the lower axis fixed parts 4 branch off in mid course and are communicated with air supply communication grooves 13 formed within the lower axis movable parts 1 (see Fig. 2(h)). Further, air passages 19 formed within upper axis fixed part 10 are connected with the air supply communication grooves 13 through air supply communication pipes (passages) 14 (see Fig. 2(h)).
• the lay-out of the air pad 7, air passage 6 opening and exhaust tunnel 20 openings on the upper surface of the lower axis fixed part 4 is shown in Fig. 2(g).
• the supporting air supplied to the air pads 17 of the upper axis subsequently flows into air exhaust grooves 16, which are formed in movable part 15 of the upper axis.
• air exhaust grooves 16 and the inner air exhaust pipes (passages) 18 formed within the upper axis fixed part 10 are connected through air exhaust tunnels (31 - see Fig. 3, which is a cross-sectional view of the fixed and movable parts of the upper axis) as is the case with the lower axis
• the supporting air that flowed into the air exhaust grooves 16 is then exhausted outside of the vacuum chamber through the inner air exhaust pipe 18, air exhaust communication pipes (passages) 12, air exhaust communication grooves 1 1 and the inner air exhaust pipes 9.
• tunnels 31 define apertures 31' in the surface of upper axis fixed part 10, which communicate with the grooves 16 in the upper axis movable part 15.
• the structure of pipes 18 and passages 19 can be appreciated from Figs. 2(d) and 2(e).
• Fig. 2(c) shows the locations of the air pad 17 and tunnel apertures 31' on the surface of the upper axis fixed part 10.
• Fig. 4 is a plan view of the inner surface of one side (of the 4 sides) of movable part 15 of the upper axis.
• the air exhaust groove 16 extends around the circumference of the inner surface of the side of the movable part 15 so as to surround its corresponding air pad 17 (located on the fixed part 10 of the upper axis). Accordingly, all air expelled into the air pad 17 will be received by air exhaust groove 16, and prevented from entering the vacuum environment in which the air bearing is used.
• the longitudinal legs 16a of the groove 16 remain in communication with the air exhaust tunnels 31 so that the exhausted air is transmitted through inner air exhaust pipes 18, air exhaust communication pipes 12, air exhaust communication grooves 11 , inner air exhaust pipes 9, and ultimately exhausted through air exhaust pipes 3.
• the inner surface of each of the four sides of the upper axis movable part 15 have exhaust grooves 16 similar to what is shown in Fig. 4.
• the inner surfaces of each of the four sides of the lower axis movable parts 1 have grooves 8 structured similar to grooves 16 (see Figs. 2(h), 5(a) and 5(b)).
• the grooves 8 and 16 can have a pattern other than what is shown in Fig. 4.
• the end legs 16b can extend entirely across the inner surface, rather than stopping where they intersect the longitudinal legs 16a.
• two grooves 16a and 16b can be provided in a modified upper axis movable part 15' as shown in Figs. 5(c)-5(e).
• Each of the grooves 16a, 16b communicates with groups of tunnel apertures 3 lb' and 31a', respectively, provided on the upper axis fixed part.
• This configuration also can include four air pads 17 on each surface of the upper axis fixed part.
• a similar arrangement can be provided for the lower axis.
• the movable parts 1 and 15 should remain overlapped with their corresponding air pads 7 and 17, respectively. This is illustrated in Figs. 2(b) and Figs. 5(a)-5(e).
• the range of motion of the movable parts 1 and 15 is somewhat limited.
• a sufficiently large range of motion is achievable.
• a bearing mechanism usable in a vacuum environment is realized because, with respect to both the lower and upper axes, the supporting air does not flow into the vacuum chamber by virtue of the above mechanism.
• FIG. 6(a)-6(c) and 7(a)-7(c) illustrate embodiments in which the air pads are formed in the movable parts of the lower and upper axes.
• the arrangements of Figs. 6(a)-7(c) keep the bearing system in better balance during movement of the movable parts of the lower and upper axes.
• the structures relating to the exhaust air is the same as in the Fig. 2 embodiment.
• the movable part 1' of the lower axis includes air pads 7'. Supply air is provided to the air pads 7' via passages 27' provided in the movable parts 1'.
• the passages 27' receive the supply air from air supply communication grooves 13 which, as discussed previously, communicate with inner air supply pipes 5.
• the surfaces of the upper axis fixed part 10-1 or 10-2 include exhaust tunnel apertures 31' as in the previous embodiments, but do not include air pads. Rather, an air supply aperture 19', which is an outlet of air passages 19 in the upper axis fixed parts, is provided.
• the supply air emitted from apertures 19' is received in air supply communication grooves 37' of the movable part 15-1.
• the air then travels through air passages 19" in the movable part 15-1 until reaching the air pads 17-1.
• the air from apertures 19' is emitted into air supply communication grooves 37", and then into the air pads 17-2 of the upper axis movable part 15-2.
• air exhaust pipes having a large bore diameter do not adversely affect the bearing performance, e.g., rectilinear feeding accuracy.
• the supporting air and the exhaust air for the upper axis can be conveyed to the upper axis through one or both of the lower axis movable parts 1.
• air as used herein is intended to cover any fluid that is suitable for use in a static air bearing, and is not intended to be limited to strictly atmospheric air.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Health & Medical Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Epidemiology (AREA)
• Public Health (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)

Priority Applications (4)

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Related Child Applications (1)

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Country Status (3)

Cited By (2)

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Citations (2)

• 1999
  • 1999-02-19 JP JP11041774A patent/JP2000240651A/ja active Pending
• 2000
  • 2000-02-18 AU AU33695/00A patent/AU3369500A/en not_active Abandoned
  • 2000-02-18 WO PCT/US2000/004223 patent/WO2000049303A1/en active Application Filing

Patent Citations (2)

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