JP2003188095A - Planar projector and method for manufacturing element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a force for moving a slider, i.e., a movable member consti tuting a substrate table or a mask table in a planar device, by keeping pressure being applied to both sides of the slider at a uniform level thereby minimizing the deformation of the movable member while reducing its weight. <P>SOLUTION: A slider 10 is provided in order to move a substrate table or a mask table. The slider 10 is supported by a gas bearing 14 and separating the region of atmospheric pressure from the region of vacuum space. A pressure difference seal 16 is provided in order to sustain a pressure difference at the gas bearing 14. A pressure correction container 20 is mounted on the slider 10 while communicating with the vacuum space. Across the almost all regions of the slider 10, pressures on first and second opposite sides thereof are identical and thereby the deformation of the slider is eliminated. External gas pressure is transmitted to the slider 10 such that the sidewall 30 side of the pressure correction container 20 is in harmony with the force of the gas bearing 14. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

The invention relates to a radiation system for providing a projection beam of radiation, a support structure supporting patterning means operative to pattern the projection beam according to a desired pattern, A lithographic projection apparatus comprising: a vacuum chamber providing a vacuum beam path for a projection beam; a substrate table for holding a substrate; and a projection system for projecting a patterned beam onto a target portion of the substrate.

[0002]

As used herein, the term "patterning means" is used to impart to a radiation beam an incoming radiation beam a patterned cross section corresponding to the pattern to be formed in a target portion of a substrate. The term “light valve” may be used in this context in its broadest sense as referring to the means that can be used. Generally, the pattern will correspond to a particular functional layer of a device being formed in a target portion, such as an integrated circuit or other device (see below). Examples of such patterning means include: -Mask. The concept of masks is well known in the lithographic art, and includes mask types such as binary, alternating phase shifts, and attenuated phase shifts, as well as various hybrid mask types. Positioning such a mask in the radiation beam causes the radiation impinging on the mask to be selectively transmitted (for a transmissive mask) and reflected (for a reflective mask) according to the pattern of the mask. In the case of a mask, the support structure is typically a mask table, which ensures that the mask holds the mask in the desired position in the incoming radiation beam and, if desired, has relative movement with respect to the beam. to enable. -Programmable mirror array. One example of such an element is a matrix-addressable surface having a viscoelastic control layer and a reflective surface. The underlying principle behind such a device is that (for example) addressed areas of the reflecting surface reflect incident rays as diffracted rays, while unaddressed areas reflect incident rays as undiffracted rays. By using a suitable filter, the undiffracted rays can be filtered out of the reflected beam, leaving only the diffracted rays. In this way
The beam becomes patterned according to the address pattern of the matrix-addressable surface. The required matrix addressing can be performed using suitable electronic means. Further information regarding such mirror arrays can be found, for example, in US Pat. Nos. 5,296,891 and 5,596,891, which are incorporated herein by reference.
523,193. In the case of a programmable mirror array, the support structure may be implemented, for example, as a frame or table which may be fixed or movable as required. -Programmable LCD array. An example of such a structure is provided in US Pat. No. 5,229,872, which is incorporated herein by reference. As mentioned above, the support structure in this case may be implemented as, for example, a frame or a table that can be fixed or movable as required. For clarity, in the remainder of this description, at certain points, particular references may be made to examples involving a mask and mask table. However, the general principles discussed in such cases should be understood in the context of broad patterning means as described above.

For example, flat panel projectors can be used in the manufacture of integrated circuits (ICs). In such cases,
The patterning means produces a circuit pattern corresponding to the individual layers of the IC, which pattern is formed on a substrate (silicon wafer) coated with a layer of radiation-sensitive material (resist) (eg from one or more dies). Image) on the target portion. In general, a single wafer will contain a whole network of adjacent target portions that are successively projected through the projection system, one at a time. In current devices that employ patterning with a mask on a mask table, it is possible to make a distinction between two types of machines. In one type of flat panel projection device, each target portion is illuminated by exposing the entire mask pattern onto the target portion in a single operation. Such devices are commonly referred to as wafer steppers. In an alternative device, commonly referred to as a step-and-scan device, each target portion gradually scans a mask pattern under a projection beam in a predetermined reference direction (“scan” direction), while Irradiation is performed by synchronously scanning a substrate table parallel or anti-parallel to the direction. Since, in general, the projection system will have a magnification factor M (generally <1), the speed V at which the substrate table is scanned is a factor M times the speed at which the mask table is scanned. Further information regarding the lithographic printing apparatus described herein can be gleaned from US Pat. No. 6,046,792, which is incorporated herein by reference.

In a manufacturing process using a lithographic projection apparatus, a pattern (eg in a mask) is imaged on a substrate which is at least partially covered by a layer of radiation sensitive material (resist). Prior to this imaging step, the substrate may be subjected to various processes such as priming, resist coating and soft bake.
After exposure, the substrate may be subjected to other processes such as post-exposure bake (PEB), development, hard bake and measurement / inspection of the imaged formation. Such an array process is used as a basis for patterning individual layers of a device such as an IC. Such patterned layers may then be subjected to various processes to finish all the individual layers, such as etching, ion implantation (doping), metallization, oxidation, chemo-mechanical polishing, etc. Good. If several layers are required, the whole procedure, or a variant thereof, will have to be repeated for each new layer. Finally, an array of devices is created on the substrate (wafer). These elements can then be separated from each other by techniques such as dicing or sawing, after which the individual elements can be mounted on a carrier connected to pins or the like. Further information regarding such methods is included herein by reference, 1997 ISBN 0-07-0772.
50-4, Peter van Zant, published by McGraw-Hill Publishing Company, "Microchip Fabrication: A Practical Guide to Semiconductor Processing" (Microchip Fabrication:
A Practical Guide to Semico
It can be collected from a book named ndector Processing).

For clarity, the projection system is sometimes referred to below as a "lens", but this term covers various types of projection systems including, for example, refractive optics, reflective optics, and catadioptric optics. It should be interpreted broadly as what is done. The radiation system also includes elements that operate according to any of these design types for directing, shaping, or controlling a projection beam of radiation, such elements also being collectively or individually Sometimes referred to as "lens". Further, the plate apparatus may be of the type having more than one substrate table (and / or more than one mask table). In such a "multi-stage" device, additional tables can be used in parallel, or preparatory steps can be performed on one or more tables while using one or more tables for exposure. . For example, a multi-stage plate apparatus is described in US Pat. No. 5,969,441 and International Patent No. WO 98/40791, which are hereby incorporated by reference.

In such a flat plate apparatus, it is typically necessary to provide areas of different atmospheric pressure in the apparatus, for example, one area is atmospheric pressure and the other area is vacuum. However, it is necessary to provide elements within the device that are free to move, but separate the areas of different pressure. Therefore, there is a need to provide a device having a bearing which allows movement of the element and a vacuum seal which holds a differential pressure between the regions separated by the movable element.

In the accompanying drawings, FIG. 2 (a) schematically illustrates such a vacuum sealed gas bearing assembly. It is composed of a slider 10 separating a gas region at atmospheric pressure from a vacuum chamber 12 containing a vacuum. A gas bearing 14 is provided at the boundary between the slider 10 and the vacuum chamber 12. This bearing is
It may consist of one or more holes or grooves from which gas is pumped so as to support the slider 10 and to provide a cushion of gas which allows the slider to move with very little friction. The holes or grooves from which the gas is pumped can be separated by lands in which the gas is under pressure. The movement of the slider 10 may be provided by means (not shown) such as an electromagnetic actuator or motor.

The differential pressure seal 16 is also provided at the boundary between the slider 10 and the vacuum chamber 12. Differential pressure seal 16
Consists of a series of one or more grooves or holes through which the gas is sucked by a vacuum pump. for that reason,
The gas discharged by the gas bearing 14 and moving in the direction toward the vacuum inside the vacuum chamber 12 is swept by the differential pressure seal 16.

Further details regarding vacuum sealed gas bearing assemblies can be found, for example, in US Pat. No. 4,191,385, which is incorporated herein by reference.

One problem with such an assembly is
As shown in FIG. 2 (b), the atmospheric pressure outside the vacuum space exerts a force distributed over the upper surface of the slider 10, but on the opposite side of the slider 10 it corresponds to that exerted by the vacuum. Powerless, instead Figure 2 (b)
There is only a force in the gas bearing indicated by the large upward arrow at. As a result of the force distribution, the slider 10 tends to deform due to the large bending inertia applied to it. However, deformation is unacceptable due to the high accuracy requirements for the sliding surfaces in gas bearings. In the figure, the air gaps between the sliding surfaces are not shown to scale. In practice, it is extremely small and the surfaces must be flat and parallel with a high degree of tolerance. As a result, in the conventional design it is extremely rigid and therefore the slider 10 is very heavy to prevent any deformation of the sliding surface. As a result, there arises a problem that a large force is required to displace the heavy slider 10 for that reason.

When a gas bearing assembly is used in a flat plate apparatus, for example as described above, to support the sliders that make up the substrate or mask table, these tables must move very quickly, and The need for very frequent accelerations results in the problem of requiring a great deal of force due to the weight design and heavy mass, which means a great loss of power in the device.

[0012]

The present invention seeks to at least partially mitigate the aforementioned problems.

[0013]

This and other objects are, according to the invention, a flat-panel projection device as described in the opening section of the present specification, wherein: -in use, a movable member supported by gas bearings. A movable member having opposite first and second sides, the second side being exposed to the interior of the vacuum chamber; and-at least one of the first and second sides of the movable member. And a pressure compensation container provided on the first side of the movable member so as to provide a substantially uniform gas pressure over a part thereof.

By providing a substantially uniform gas pressure over at least a portion of the first and second sides of the movable member, it is possible to significantly reduce bending inertia with respect to the movable member, so that the movable member is significantly reduced. Of the gas bearing while still maintaining the necessary tolerances on the sliding surface of the gas bearing while still allowing satisfactory operation. Gas pressure uniformity may be such that the pressure on one side is a rough vacuum and the pressure on the other side is an ultra-high vacuum, but both pressures are essentially zero for atmospheric pressure. It can be determined relative to atmospheric pressure, such as pressure.

It is preferable that the inside of the pressure compensation container is in communication with the region on the second side of the movable member by a passage. This allows pressure uniformity to be easily and passively achieved without the need for any additional equipment, pumps, pressure monitoring or the like.

The pressure compensation container is preferably at least partially deformable. This makes it possible to reduce the weight of the container.

Preferably, at least one wall of the pressure compensation container, in use, contacts the movable member in the vicinity of the region in which the movable member is supported by the gas bearing. This means that the force exerted on the movable member by the external pressure on the pressure compensating container is generally in tune with the force exerted on the movable member by the gas bearing, and therefore the torque or bending inertia on the movable member is generally minimized. To do.

It is preferable that a hollow member is provided on the second side of the movable member, and an opening is provided from the hollow member through the movable member and the pressure compensation container. This means, for example, that air can be taken into a movable member such as a slider and the cable can be led out of the slider. A bellows is preferably provided around the opening in order to shield the inside of the pressure compensation container from the inside of the hollow member. The bellows provides a barrier that allows the interior of the pressure compensation container to be kept at a different pressure than the interior of the hollow member, and because it is a bellows, the pressure compensation container is still deformable and, importantly, the bellows That is, it is deformed so that no force is applied to the movable member. In this way, the deformation of the pressure compensation container is separated from the movable member by the bellows, thus eliminating the deformation of the sliding surface.

The movable member can be a slider that allows displacement for xy coordinate positioning of the substrate table or mask table, or the movable member can perform rotational positioning about a particular axis, or linear sliding and rotation. A rotor capable of combining both may be used.

In the pressure compensation container and in the vacuum chamber
The gas pressure on the second side of the moving member is lower than atmospheric pressure
Is preferable, more preferably the pressure is 100 Pa or less,
Or actually several times lower, i.e. many times lower
Yes, for example 10^-2  Pa (10 ^-Four  Mbar) below
Yes, it is preferably vacuum or ultra-high vacuum.

According to another aspect of the invention: providing a substrate at least partially covered by a layer of radiation sensitive material; and providing a projection beam of radiation using a radiation system. -Providing a vacuum beam path for the projection beam in a vacuum chamber, -patterning the cross-section of the projection beam using patterning means, -on a target portion of the layer of radiation-sensitive material. Projecting a patterned beam of radiation onto a movable member supported by a gas bearing, the movable member having opposite first and second sides. 2 side is provided with a movable member exposed to the inside of the vacuum chamber, a pressure compensation container is provided on the first side of the movable member, and the first side of the movable member is provided. Device manufacturing method characterized by including the steps of a generally uniform gas pressure in at least a portion of the second side of the fine said movable member is provided.

Although particular reference is made herein to the use of the device according to the invention in the manufacture of ICs, it should be clearly understood that such devices have many other possible applications. For example, the device according to the invention may be employed in the manufacture of integrated optical systems, guiding and sensing patterns for magnetic domain memories, liquid crystal display panels, thin film magnetic heads, etc. Those of skill in the art will recognize that the terms "reticle,""wafer," or "die" as used herein, in connection with such alternative applications, respectively, refer to the more general terms "mask", "substrate", and We recognize that the term “target part” should be replaced and considered.

As used herein, ultraviolet light (eg, wavelengths 365, 248, 193, 157 and 126 nm).
And “UV” to cover all types of electromagnetic radiation, including EUV (eg, deep UV in the wavelength range 5-20 nm), and particle beams such as ion beams or electron beams. Uses the term.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings.

In the figures, corresponding reference symbols indicate corresponding parts.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 schematically shows a flat panel projection device according to the present invention. The device includes: A radiation system LA, IL for supplying a projection beam PB of radiation (which is eg UV or EUV radiation, electrons or ions); a first for holding a mask MA (eg a reticle);
Object (mask) holder of the first positioning means PM for accurately positioning the mask with respect to the object PL.
First object table (mask table) M connected to
T. A second object (substrate) holder for holding the substrate W2 (for example, a silicon wafer coated with a resist) is provided and is connected to the second positioning means P2W for accurately positioning the substrate with respect to the object PL. A second object table (substrate table) W2T; ● A third object (substrate) holder for holding a substrate W3 (for example, a resist-coated silicon wafer) is provided, and the substrate is accurately positioned with respect to the object PL. A third object table (substrate table) W3T for: • a projection system (“lens”) PL (eg a refractive or catadioptric lens) for imaging the illuminated portion of the mask MA onto a target portion C of the substrate W. System, mirrors, or array of field deflectors).

The radiation system is a light source LA that produces a beam of radiation (eg, an undulator or wiggle provided around the electron beam path in a storage ring or synchrotron).
r), plasma sources, electron or ion sources, mercury lamps or lasers). This beam is an irradiation system I
It is adapted to traverse the various engineering elements contained in L, so that the resulting beam PB has a desired shape and intensity distribution in its cross section.

The beam PB is then applied to the mask table MT.
Collides with the mask MA held by the mask holder in. Selective reflection (or transmission) by mask MA
As a result, the beam PB passes through a "lens" PL, which focuses the beam PB on the target portion C of the substrates W2, W3. The substrate table W2 is supported by the positioning means P2W, P3W and the interference dislocation measuring means IF.
T, W3T can be precisely moved to position different target portions C in the path of the beam PB, for example. Similarly, the positioning means PM and the interferometric dislocation measuring means IF are for accurately positioning the mask MA with respect to the path of the beam PB, for example after the mask MA has been mechanically retrieved from the mask library or during a scanning movement. Can be used for In the prior art, the movement of the object tables MT, W2T is generally shown in FIG.
This is accomplished with the help of long stroke modules (coarse positioning) and short stroke modules (fine positioning) not explicitly shown in FIG.

The depicted apparatus can be used in two modes. In step mode, the mask table MT is basically held stationary and the entire image of the mask is projected onto the target portion C in one operation (ie a single “flash”). The substrate table W2T is then moved in the X and / or Y direction so that a different target portion C can be illuminated by the beam PB. -In scan mode, essentially the same procedure applies, except that a given target portion C is not exposed in a single "flash". Instead, the mask table MT is movable at a velocity v in a predetermined direction (the so-called “scan direction”, eg the Y direction), and therefore the projection beam P
B is made to scan over the image of the mask, while at the same time the substrate table W2T moves in the same or opposite direction with a velocity V = Mv. M is the magnification of the lens PL (for example,
M = 1/4 or 1/5). In this way, it is possible to expose a relatively large target portion C without having to compromise on resolution.

In the flat panel projection device according to the present invention, the first
At least one of the second object table and the second object table is provided in the vacuum chamber 8 schematically shown in FIG.

Referring to FIG. 3A, the mask table MT or the substrate table W of the above-described embodiment of the present invention.
The slider arrangement used to move the 2T, W3T is schematically illustrated in cross section. Members corresponding to those shown in FIG. 2A are designated by corresponding reference symbols, and therefore description thereof will not be repeated. The device comprises a movable member, in this case a slider 10. First side 22 of slider 10
There is a pressure compensating container 20, and a gas (gas) such as air or purge gas, which may have a substantially atmospheric pressure, exists outside thereof. Below the slider 10, on its second side, is a vacuum space containing depressurized gas. The slider 10 is supported by the air bearing 14, and the differential pressure between the vacuum space and the external gas is the same as that shown in FIG.
As described above with reference to FIG.

A passage 26 is provided through the slider 10 so that the interior of the pressure compensation container 20 communicates with the vacuum space in the region of the second side 24 of the slider 10. When the pressure equilibrium is reached, the pressure inside the pressure compensating container 20 becomes the same as the pressure in the vacuum space, and thus also becomes a vacuum. The inside of the pressure compensation container 20 does not necessarily have to be provided with the passage 26, and may instead be depressurized and exhausted by an independent gas exhausting means. The reason why this is advantageous is that outgassing does not allow any contaminants present in the pressure compensation container 20 to reach the highly contaminant sensitive vacuum space on the second side 24 of the slider 10. Either of the above methods
The gas pressures on the major portions of the first side 22 and the second side 24 of the slider 10 are the same and thus the slider 10
In contrast, there is no significant bending inertia, so the slider does not need a high degree of rigidity and can be lighter in weight. Of course, there is still external gas pressure in the upper part of the device, but the upper wall 28 of the pressure compensation container
Transmits the resulting force to the sidewall 30 of the pressure compensation container 20. Thus, instead of distributing pressure over the first side 22 of the slider 10, that pressure is concentrated on the slider where the slider 10 contacts the sidewall 30. Side wall 30
Are positioned so that they correspond to the position of the gas bearings 14. As a result, as shown in FIG. 3B, the force applied to the slider 10 by the side wall 30, which is indicated by a large downward arrow in FIG.
Gas bearing 1 indicated by an upward arrow in (b)
To the force on the slider 10 from 4.

In use, the upward force of the air bearing 14 needs to react not only to atmospheric pressure on the upper portion of the device, but also to the weight of the slider 10 and associated components. There is still some bending inertia acting on the slider 10 since the weight of the slider 10 resulting from the action of the force of gravity is of course distributed over the slider 10, which is inherent to the device, It cannot be excluded, but this is reduced by the fact that the slider 10 can be made lighter, since it does not deform under the gas pressure of 10 ⁵ Pa acting on its upper surface.

As shown in FIG. 3A, the pressure compensation container 2
0 upper wall 28 is shown as deformable due to the fact that it is bowed inward by the external gas pressure acting on the upper wall 28, which is uncorrected due to the vacuum inside the pressure compensating vessel 20. ing. Of course, it is not essential for the present invention that the pressure compensation container 20 is partially deformable, but this is not the case.
This is advantageous in reducing the rigidity of 0 and allowing it to be lighter in weight. The point of the pressure compensation container 20 is to change the distribution of the force due to the gas pressure over the slider 10, so that they are not distributed over the first surface 22 of the slider, but rather of the pressure compensation container 20. It is to be transmitted through the side wall 30.

Embodiment 2 Another preferred embodiment of the present invention is shown in FIG. Figure 3
Only the features different from (a) will be described. Although in the previous figures the slider 10 has been schematically illustrated as a simple beam, in practice a more desirable shape is shown in FIG. 4, where air or other gas is introduced inside the slider. A hollow member is provided on the lower side of the slider 10 in order to obtain it. In order to lead out a cable or the like from the inside of the hollow member 32, the upper wall 32 of the pressure compensation container 20 is passed through the slider 10.
An opening 34 is provided therethrough. A gas-tight seal is provided around the opening 34 to seal the vacuum inside the pressure compensation container 20 from the outside atmosphere that may pass through the opening 34 into the hollow member 32 with any desired cable (not shown). A bellows 36 is provided. Bellows 36 are made of metal or other suitable material and are in the form of concertinas. Because the bellows 36 are rockable, the upper wall 28 of the pressure compensation container is deformable. However, since the bellows 36 has zero or very little elasticity, when compressed vertically, no force is actually transmitted to the first side 10 of the slider 10. in this way,
The upper side wall 28 of the pressure compensation container 20 has the air bearing 14
Can be deformed without transmitting a force to the slider 10 at a point far away from the support point provided by, and can be made lightweight. Most of the force generated from atmospheric pressure on the upper side wall 28 of the pressure compensating container 20 is still transmitted via the side wall 30 located in alignment with the air bearing 14. There is a small additional force on slider 10 that is equal to the area of opening 34 times atmospheric pressure, but this force acts on slider 10 where the wall of hollow member 32 joins the slider. , Still much less than the total force of the gas pressure on the upper wall 28 of the pressure compensation container 20.

While a particular embodiment of the invention has been described above,
It will be appreciated that the invention may be practiced other than as described. The above description is not intended to limit the invention.

[Brief description of drawings]

FIG. 1 shows a flat panel projection device according to an embodiment of the present invention.

FIG. 2 (a) shows a schematic sectional view of a slide and its supporting device.

2 (b) schematically illustrates the force on the slider shown in FIG. 2 (a).

FIG. 3 (a) schematically illustrates a cross section of a slider device embodying the present invention.

FIG. 3 (b) schematically illustrates the force shown in FIG. 3 (a).

FIG. 4 schematically illustrates in cross section another embodiment of a slider device according to the present invention.

[Explanation of symbols]

C target part IL radiation system IF interference dislocation measuring means LA radiation source MA mask MT mask table PB projection beam PL lens PM positioning means W board WT board table 10 slider 12 vacuum chamber 14 Air bearing 16 Differential pressure seal 20 Pressure compensation container 22 First side of slider 24 Second side of slider 26 passage 28 Upper wall of pressure compensation container 30 side wall 32 hollow member 34 opening 36 Bellows

Continued front page    (72) Inventor Jacob Wylovwinkel             Netherlands Eindhoven, Nord             Dobra Bantran 146 F-term (reference) 5F046 BA07 CC17 GA11                 5F056 CB21 EA14 EA15

Claims (10)

[Claims] 1. A radiation system for providing a projection beam of radiation, a support structure supporting patterning means operative to pattern the projection beam according to a desired pattern, and a vacuum beam for the projection beam. A flat panel projection apparatus comprising: a vacuum chamber providing a passage; a substrate table for holding a substrate; a projection system for projecting a patterned beam onto a target portion of the substrate; and a gas bearing in use. A movable member supported by: a movable member having first and second opposite sides, the second side being exposed to the interior of the vacuum chamber; And a pressure compensating container provided on the side to provide a substantially uniform gas pressure over at least a part of the first and second sides of the movable member. Location. 2. The two regions separated by the movable member and the pressure compensation container and having different gas pressures, one of the regions further including a region formed inside the vacuum chamber. 1. The device according to 1. 3. The differential pressure seal according to claim 2, further comprising a differential pressure seal for holding different gas pressures in the two regions while allowing the movable member to be movably supported by the gas bearing. The described device. 4. The apparatus according to claim 1, wherein the inside of the pressure compensation container is in communication with the second side of the movable member via a passage. 5. Device according to claim 1, characterized in that the pressure compensation container is at least partially deformable. 6. At least one wall of the pressure compensation container is in contact with the movable member in the vicinity of a region where the movable member is supported by the gas bearing when in use. Any one up to
The device according to paragraph. 7. A hollow member is provided on the second side of the movable member, and an opening is provided from the inside of the hollow member through the movable member and through the pressure compensation container. Any one of claims 1 to 6
The device according to paragraph. 8. The apparatus according to claim 7, wherein a bellows is provided around the opening to block the inside of the pressure compensation container from the inside of the hollow member. 9. The apparatus according to claim 1, wherein the gas pressure in the pressure compensation container and in the second side of the movable member is lower than atmospheric pressure. 10. Providing a substrate at least partially coated with a layer sensitive to radiation; providing a projection beam of radiation using a radiation system; Providing a vacuum beam path for: -using a patterning means to impart a pattern in the cross section of the projection beam; -a target of a layer of material sensitive to the patterned beam of radiation. Projecting onto a portion, the method comprising: a movable member supported by a gas bearing,
Providing a movable member having opposite first and second sides with the second side exposed to the interior of the vacuum chamber; and providing a pressure compensation container on the first side of the movable member. Stages,
Equalizing the gas pressure in the pressure compensating container on the first side of the movable member and over at least a portion of the second side of the movable member. Method of manufacturing.