NL2005374C2

NL2005374C2 - Method for arranging a lithography system on a foundation, and lithography system arranged on said foundation.

Info

Publication number: NL2005374C2
Application number: NL2005374A
Authority: NL
Inventors: Jerry Peijster
Original assignee: Mapper Lithography Ip Bv
Priority date: 2010-09-20
Filing date: 2010-09-20
Publication date: 2012-03-22
Also published as: JP2013543254A; TW201217915A; WO2012039606A1; EP2619629A1; KR20130132769A; WO2012039606A9; WO2012039606A4

Description

No. NLP185705A

Method for arranging a lithography system on a foundation, and lithography system arranged on said foundation

BACKGROUND

The invention relates to a method for arranging a vibration isolation requiring system, such as a lithography 5 system, on a foundation. The invention further relates to a vibration isolation requiring system, such as a lithography system, arranged on said foundation.

In lithography systems, for example in the manufacture of microelectronic devices (e.g. integrated 10 circuits), the demands on accuracy and precision are extreme. Lithography involves the transfer of a pattern, used to define a layer of a microelectronic device, onto a surface of a suitable substrate such as a semiconductor wafer. Modern lithography systems are capable of providing 15 patterns in which the pattern elements, as imaged or written on the substrate, having a sub-micron line width, e.g. less than one micrometer, on the substrate. Achieving such a high level of performance requires that all pattern transfer systems, positioning systems, and measuring systems of the 20 lithography system operate at their absolute limits of performance. This level of performance also requires that 2 the components of said lithography system are mounted at an accurate and substantially fixed position with respect to each other.

One approach is to mount the components of such a 5 system on top of a stiff sandwiched base plate, such as a honeycomb type mounting platform. The honeycomb structures are usually used in areas where a lightweight, high stiffness vibration-free surface is required. The typical construction of the honeycomb base plate comprises a top 10 plate and a bottom plate with a honeycomb or web structure bonded in between. The structures are known to be quite stiff when exposed to compressive loads applied normal to the top plate of the platform and it provides a rigid separation between the plates. However, such a honeycomb 15 base plate is very expensive, complicated in design, and require a long ordering time.

An other approach is to mount the components on a thick, substantially monolithic slab of granite. However in order to obtain the desired stiffness to carry a lithography 20 system, such a slab needs to be relatively thick, typically more than 300 mm, and as a consequence will be extremely heavy.

It is an object of the present invention to provide a base structure for a lithography system which 25 obviates one or more of the above mentioned disadvantages.

SUMMARY OF THE INVENTION

30 According to a first aspect, the invention provides a method for arranging a vibration isolation requiring system, such as a lithography system on a foundation, said method comprising the steps of: providing a self-carrying rigid base plate having 35 one or more struts attached thereto, wherein the one or more struts are attached to a side of said base plate that faces the foundation; 3 placing said base plate with its struts onto said foundation; providing leveling means for adjusting the distance between the base plate and the foundation; 5 adjusting the distance between the base plate and the foundation in order to obtain a desired leveling of the base plate; providing a curable resin material between the struts and the foundation; 10 curing said resin material in order to provide a rigid connection between the foundation and the struts; and placing said system on top of said base plate.

Using this method a base structure is provided wherein the foundation is used as a reinforcing part of the 15 base plate in order to obtain the desired stiffness. In realizing that the foundation can be used as a reinforcing part for a base plate in a high precision environment, the rigid base plate of the base structure of the invention needs only to be self-carrying, that is having a sufficient 20 stiffness that the base plate substantially does not bent under its own weight. In this patent application, the foundation is a load-bearing part in a building for bearing the load of the lithography system, such as a lowest load-bearing part of the building or part of the floor in the 25 room where the lithography system is arranged.

Since the rigid base plate in itself does not need to be sufficient stiff to support the whole lithography system, the base plate can be of a relatively simple design. Such a base plate may be ordered and pre-installed by a 30 customer of said lithography system, without undue costs of (overseas) transport.

Since a curable resin material is used to provide a rigid connection between the foundation and the struts of said rigid base plate, the method of the invention allows 35 for fixing the base plate to an even rough and simple top surface of said foundation in a correct and strengthening manner. The leveling means can correct for any deviation of 4 said foundation from a flat, horizontal surface. In addition, the curable resin material fills any space between the struts and the foundation, and provides sufficient strength after curing to support the rigid base plate and 5 the system arranged on said base plate.

In an embodiment said method further comprising the step of removing the leveling means. Thus the leveling means are only required during the arrangement of the rigid base plate on the foundation and the connecting of said 10 struts of said base plate to said foundation by means of said curable resin material. After curing the leveling means can be removed. Said leveling means comprises, for example, one or more hydraulic lifting jacks, screw jacks or lifting screws .

15 In an embodiment said method further comprising the steps of: providing a rim onto the foundation, which rim surrounds a foundation area for said base plate; and providing said curable resin material onto the 20 foundation area as a pool of curable resin material, wherein the one or more struts are in contact with said pool of curable resin material, preferably wherein all struts are completely in contact with said pool of curable resin.

The resin material, after it has cured, provides a 25 substantially continue top layer of resin material covering said foundation area within the rim. Such a top layer of resin material provides a large adhesion surface, and thus a good adhesion to the foundation.

In an embodiment, said one or more struts are at 30 least partially submerged in said pool of curable resin material. This provides a mechanical bond between the struts and the top layer of resin material.

In an embodiment said curable resin material comprises an adhesive. This provides a chemical bond between 35 the struts and the top layer of resin material.

In a preferred embodiment said one or more struts are at least partially submerged in a pool of adhesive, 5 which provides both a mechanical and a chemical bond between the struts and the top layer.

Although the rim may be removed after the curing of said curable resin, it is preferred to use a decorative 5 rim. By using a decorative rim, there is no need to remove the rim, which is a difficult procedure because the rim tends to stick to the curable resin material.

In an embodiment, said curable resin material is a material having a low or substantially no shrinkage during 10 curing. In an embodiment, said shrinkage is less than one percent. Using a curable resin material with a low shrinkage so as to at least substantially maintain the absolute position between the rigid base plate and the foundation before, during and after the curing of the resin material. 15 Furthermore, the use of a low shrinkage resin material substantially prevents the building up of any stress inside the resin material during the curing thereof.

In an embodiment, said curable resin material comprises a substantially non-shrinkable epoxy. In an 20 embodiment, said epoxy comprises substantially no or a minimal amount of solvent.

In an embodiment, the one or more struts are releasable connected to the base plate. This embodiment allows for replacing a base plate once the struts are 25 connected and/or bonded to the foundation. The releasable connection provides fro an easy and relatively inexpensive upgrade facility.

It is preferred that the bottom surface of the base plate is substantially flat. Such a base plate with a 30 flat bottom surface can be readily exchanged by an other base plate. Preferably also the top surface of the base plate is substantially flat.

In an embodiment, the foundation comprises a foundation plate or block. In an embodiment, the foundation 35 plate or block is a concrete foundation plate or block, or a reinforced concrete foundation plate or block. Such a foundation plate or foundation block may be manufactured on 6 site.

In an embodiment, said base plate comprises a plate of granite. Since said base plate only needs to be self-carrying, the plate of granite can be relatively thin, 5 in particular 150 mm or less, preferably 100 mm or less. Such a relatively thin granite base plate can be ordered locally, e.g. near to the site of the customer, and preinstalled on the foundation without undue costs of transport.

10 In an embodiment, said base plate is provided with mounting members at a top side for mounting the lithography system onto said base plate. The mounting members, such as interfaces or connectors, can be accurately positioned on said base plate in correspondence with the position of 15 supporting members of said lithography system, enabling a quick installing of said lithography system onto said base plate.

In an embodiment, at least one strut is arranged below one mounting member, preferably below the centre line 20 thereof. This provides for a direct transfer of the weight of the lithography system as carried by said mounting member, via said at least one strut to said foundation.

According to a second aspect, the invention provides a lithography system arranged on a foundation, 25 wherein said foundation is provided with a self carrying base plate having one or more struts attached thereto, wherein the one or more struts are attached to a side of said base plate that faces the foundation, wherein said one or more struts are rigidly connected to said 30 foundation by a resin material, and wherein said lithography system is arranged on top of said base plate.

Preferably said self-carrying base plate, is a rigid base plate. Preferably said resin material comprises a 35 cured resin material.

In an embodiment, said one or more struts are at least partially submerged in said cured resin material.

7

In an embodiment said cured resin material comprises an adhesive.

In an embodiment, said cured resin material is a material having a low or substantially no shrinkage during 5 curing. In an embodiment, said shrinkage is less than one percent.

In an embodiment, said cured resin material comprises a substantially non-shrinkable epoxy.

In an embodiment, the one or more struts are 10 releasable connected to the base plate.

In an embodiment, the foundation comprises a foundation plate. In an embodiment, the foundation plate is a concrete foundation plate.

In an embodiment, said base plate comprises a 15 plate of granite.

In an embodiment, said base plate is provided with mounting members at a top side for mounting the lithography system onto said base plate. In an embodiment, at least one strut is arranged below one mounting member.

20 According to a third aspect, the invention relates to a base plate for supporting a vibration isolation requiring system, such as a lithography system, wherein the base plate comprises a bottom side that, in use, faces a foundation, wherein said bottom side is provided with struts 25 or at least is prepared for receiving struts, wherein said struts are arranged for rigidly connecting said base plate to the foundation, such as a concrete foundation block. The base plate of the invention may be kept much thinner in order to arrive at a sufficient stiffness for supporting a 30 vibration isolation requiring system. Advantages of such thinner base plate, apart form material and transportation costs, are that it may be produced quicker and transported more easily. In general a less complicated logistic preparation is required, e.g. the choice of transportation 35 means is considerably enlarged, as well as the choice in sites capable of manufacturing such a base plate.

In an embodiment, said struts are releasable 8 connected to said base plate. In this embodiment, the base plate may, if so desired, be easily and cost-effectively be replaced, for example in case of any system upgrade. Also, only a relatively small material part of the foundation 5 system needs to be sacrificed for such an update.

A further advantage of said releasable struts is that the foundation may be prepared and/or the struts may be connected to the foundation while the base plate is being prepared and/or transported. For preparing the foundation, a 10 light weight, e.g. honeycomb stiffened mock-up plate may be used, rather than the original base plate. The mounting of the struts on to the foundation can be established without the presence of the base plate. When arrived, the base plate may instantly be positioned on the struts which are secured 15 to the foundation.

In an embodiment, said base plate is a self carrying base plate.

In an embodiment, the base plate comprises a top side that, in use, faces the system, wherein said top side 2 0 comprises one or more mounting members or at least is prepared for having one or more mounting members attached thereto, wherein said mounting members are connectable between said base plate and said system. Said base plate is provided with mounting members at the top side for mounting 25 the system, such as a lithography system, onto said base plate.

In an embodiment, at least one of said mounting members is arranged at least partially in line with at least one of said struts. In an embodiment, at least one strut is 30 arranged below one mounding member.

In an embodiment, at least one of said struts is provided with anchoring members at a side facing away from said base plate.

In an embodiment, said plate is provided with 35 bores having a threaded insert fixedly received therein for connecting any of said struts and/or mounting members to said base plate.

9

In an embodiment, said base plate comprises a plate of granite.

According to a fourth aspect, the invention related to a use of the above mentioned base plate for 5 supporting a vibration isolation requiring system, such as a lithography system. An other example of such a vibration isolation requiring system is a microscope system, such as an electron microscope or an atomic force microscope.

The various aspects and features described and 10 shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications.

15

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of 20 an exemplary embodiment shown in the attached drawings, in which:

Figure 1 is a schematic presentation of a rigid base plate of the invention;

Figures 2 to 5 present a schematic side view of 25 various steps of a first example of a method for arranging a lithography system on a foundation, in particular a floor area; and

Figures 6 to 8 present a schematic side view of various steps of a second example of a method for arranging 30 a lithography system on a foundation, in particular a foundation block.

DETAILED DESCRIPTION OF THE INVENTION 35

Figure 1 shows a self-carrying rigid base plate 1 for placing a lithography system onto a foundation. Said 10 base plate 1 may for example comprise a relatively thin honeycomb type mounting platform. However preferably the base plate 1 comprises a relatively thin monolithic plate of granite. The base plate 1 is provided with eight struts 5 5 attached to a bottom side 2 of said base plate 1 that, in use, faces the foundation.

The struts 5 are releasable attached to the bottom side 2 via screws or bolts. Each strut 5 comprises a substantially square cylinder having substantially flat side 10 walls, which are for example 10 cm high. The struts 5 are manufactured using a profiled or moulded wall material, in order to provide strong and/or rigid struts. The upper end and lower end of each strut 5 is provided with a flange 6. The flange 6 extends approximately 5 cm beyond the outer 15 side of the side walls of the strut 5. Between the flange at the upper end (not shown) and the flange 6 at the lower end, strengthening ribs 7 are provided. The strengthening ribs 7 are rigidly connected, for example by welding, to the upper and lower flange and to one of the side walls. In use the 20 ribs 7 extend substantially vertically between the upper and lower flange 6.

The lower flange 6 is used as an anchoring member for connecting the strut 5 to the foundation as described in more detail below.

25 The lithography system or a part thereof, may be mounted directly on top of the base plate 1 surface 3. In the embodiment shown in figure 1, the top side 3 of said base plate 1 is provided with mounting members 4 for mounting the lithography system, in particular the vacuum 30 chamber of said system, onto said base plate 1.

As shown in figure 1, the mounting members 4 are provided on a part of the base plate 1. This part is also provided with a cut-out 8 which provides space for mounting equipment underneath the vacuum chamber of the system, in 35 particular measuring equipment, such as a camera. In prior art base plates, such a cut-out 8 cannot be made because it considerably decreases the rigidity of the base plate. In 11 the base plate 1 of the invention, where the foundation or floor is used as a reinforcing part for a base plate 1, the cut-out 8 substantially does not lessen the rigidity of the base plate 1 which is connected to the foundation or floor.

5 In order to pass the weight of the vacuum chamber of the lithography system on to the foundation or floor one or more of the mounting members 4 are arranged above one strut 5.

As shown in figure 1, the struts 5 below the part 10 of the base plate 1 which is provided with the mounting members 4 for mounting the vacuum chamber of the lithography system, are larger than the other struts. In this example, ten mounting members 4 are evenly arranged above the four large struts 5.

15 As shown in figure 1, a second part 9 of the base plate 1 is not provided with mounting members 4. This part 9 is used for mounting wafer handling equipment and actuators.

Before installing a lithography system, the above described base plate 1 is placed at the location where the 20 system has to be installed. The base plate 11 with its struts 15 is arranged on a foundation 10, which is substantially separate from a surrounding floor 30. This can at least partially stop vibrations in or on the floor 30 from reaching the foundation 10 and be transmitted to the 25 base plate 11.

As shown in figure 2, the self-carrying rigid base plate 11, having one or more struts 15 attached thereto, is provided. The upper end of the struts 15 is provided with an upper flange 18 which is attached to a flat bottom side 12 30 of said base plate 11 that faces the foundation 10. The lower end of the struts 15 is provide with a lower flange 16, which acts as an anchoring member. As shown in figure 2, said base plate 11 is placed with its struts 15 onto said foundation 10. Furthermore the top side 13 comprises the 35 mounting members 14.

Subsequently leveling means 17, in particular screw jacks or lifting screws, for adjusting the distance 12 between the base plate 11 and the foundation 10, are provided. As shown in figure 3, the leveling means 17 are placed on top of blocks 19. The leveling means 17 are used for adjusting the distance between the base plate 11 and the 5 foundation 10 in order to obtain a desired leveling of the base plate 11.

On the one hand, the curable resin material 21 can be provided locally, that is only at or near the anchoring members of the struts 15.

10 On the other hand, the curable resin material 21 can be made to cover the foundation area at and near the base plate 11. This option is chosen in the example in figure 4. Before providing the curable resin material 21, a rim 20 is placed onto the foundation 10, which rim 20 surrounds a 15 area for said base plate 11. Subsequently the curable resin material 21 is provided onto the foundation area as a pool of curable resin material, wherein the anchoring members 16 of all struts 15 are wholly in contact with said pool of curable resin material 21. Said curable resin material 21 20 comprises a substantially non-shrinkable epoxy, such as a two-component epoxy (Rocapox EP™ from the firm Prokol) with our without a filler. This material has a low or substantially no shrinkage during curing, in particular a shrinkage of less than one percent.

25 As shown in figure 4, the curable resin material 21 is also provided between the anchoring members 16 of the struts 15 and the foundation 10. The anchoring members 16 of the all struts 15 are completely in contact with_said pool of curable resin material 21. After the resin material 21 30 has set or cured, it provides a rigid connection between the floor 10 and the struts 15.

Now the leveling means 17 can be removed and the base plate 11 attached on the foundation 10 is ready to receive the lithography system 22, as schematically depicted 35 in figure 5.

In a second example, as shown in figure 6, the location comprises a solid floor 30. The base plate 31 can 13 be placed directly onto that floor 30.

Furthermore, as shown in figure 6, the leveling means comprises one or more beams 39 which reach underneath the base plate 31, and wherein each beam 39 rests on two 5 hydraulic jacks 37 for adjusting the distance between the base plate 31 and the floor 30. As shown in figure 6, the hydraulic jacks 37 are placed at a distance from the base plate 31, outside the floor area that is destined to be covered by the curable resin material 40, as shown in figure 10 7. The hydraulic jacks 37 are used for adjusting the distance between the base plate 31 and the floor 30 in order to obtain a desired leveling of the base plate 31. Preferably the hydraulic jacks 37 are provided with mechanical locking or retaining members in order to secure 15 the position of the base plate 31 after leveling.

Before providing the curable resin material 41, a rim 40 is placed onto the floor 30, which rim 40 surrounds a floor area for said base plate 31. Subsequently the curable resin material 41 is provided onto the floor area as a pool 20 of curable resin material, wherein the flanges 36 which act as anchoring members of the struts 35 are all, substantially completely, in contact with said pool of curable resin material 41. Said curable resin material 21 comprises a substantially non-shrinkable epoxy that comprises 25 substantially no or a minimal amount of solvent, for example Rocapox EP™ from the firm Prokol. Alternatively an substantially non-shrinkable adhesive can be use.

As shown in figure 7, the curable resin material 41 is also provided between the anchoring members 36 of all 30 struts 35 and the floor 30. After the resin material 41 has set or cured, it provides a rigid connection between the floor 30 and the struts 35.

Now the leveling means 37, 39 and the rim 40 can be removed and the base plate 11 attached on the floor 30 is 35 ready to receive the lithography system 32, as schematically depicted in figure 8. The lithography system 32 is at its bottom side provided with a camera 33 which is arranged in 14 the cut-out 8 of the base plate 31 analogous as in the base plate 1 of figure 1.

Figures 5 and 8 thus show a lithography system 22, 32 arranged on a floor 30 or a foundation 10, wherein said 5 floor 30 or foundation 10 is provided with a self-carrying rigid base plate 11, 31 having one or more struts 15, 35 attached thereto, wherein the one or more struts 15, 35 are attached to a side of said base plate 11, 31 that faces the floor 30 or foundation 10, wherein said one or more struts 10 15, 35 are provided with anchoring members at a side facing away from said base platell, 31, wherein said anchoring members are rigidly connected to said floor 30 or said foundation 10 by a cured resin material 21, 41, and wherein said lithography system 22, 32 is arranged on top of said 15 base plate 11, 31.

In summary, the invention relates to a lithography system arranged on a foundation, for example part of the floor in the room where the lithography system is arranged, and a method for arranging a lithography system on a 20 foundation. The foundation is provided with a self-carrying rigid base plate having one or more struts attached thereto. The one or more struts are attached to a side of said base plate that faces the foundation. The one or more struts are rigidly connected to the foundation by a cured resin 25 material. This provides a base structure wherein the foundation is used as a reinforcing part of the base plate in order to obtain the desired stiffness. The said lithography system is arranged on top of said base plate.

It is to be understood that the above description 30 is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the present 35 invention.

Claims

A method for placing a vibration isolation-requiring system, such as a lithography system, on a foundation, the method comprising the steps of: 5. providing a self-supporting rigid base plate with one or more supports attached thereto, the one or more supports are attached to a side of the base plate that faces the foundation; placing the base plate with its supports 10 on the foundation; providing leveling means for adjusting the distance between the base plate and the foundation; adjusting the distance between the base plate 15 and the foundation to obtain the desired flat water adjustment of the base plate; providing a curing resin material between the supports and the foundation; curing the resin material to provide a fixed connection between the foundation and the supports; and placing the system on top of the base plate.

The method of claim 1, further comprising the step of removing the leveling means.

3. A method according to claim 1 or 2, further comprising the steps of: providing an edge on the foundation, which edge surrounds a foundation area for the base plate; and providing the curing resin material in the foundation area as a pool of curing 2005374 resin material, wherein the one or more supports are each in contact with the pool of curing resin material.

The method of claim 3, wherein the supports are at least partially submerged in the pool 5 of cured resin material.

The method of claim 3 or 4, further comprising the step of removing the edge after the curing resin material has cured.

6. A method according to any one of the preceding claims, characterized in that the curing resin material is a material with a low or substantially no shrinkage during curing.

Method according to claim 6, characterized in that the shrinkage is less than one percent.

Method according to claim 6 or 7, characterized in that the curing resin material comprises a substantially non-shrinking epoxy.

9. A method according to claim 8, characterized in that the epoxy comprises substantially no or a minimum amount of solvent.

Method according to claim 6, 7, 8 or 9, characterized in that the curing resin material comprises an adhesive.

A method according to any one of the preceding claims, characterized in that the one or more supports are releasably connected to the base plate.

A method according to any one of the preceding claims, characterized in that the foundation comprises a foundation plate.

A method according to claim 12, characterized in that the foundation plate is a concrete foundation plate.

14. A method according to any one of the preceding claims, characterized in that the base plate comprises a granite plate.

A method according to any one of the preceding claims, characterized in that the base plate is provided with mounting members on an upper side for mounting the lithography system on the base plate.

16. Method as claimed in claim 15, characterized in that at least one support is placed under one mounting member.

17. Lithography system placed on a foundation, wherein the foundation is provided with a self-supporting base plate with one or more supports attached thereto, the one or more supports being attached to a side of the base plate facing the foundation, the supports fixedly connected to the foundation by a resin material, and wherein the lithography system is placed on the top of the base plate.

The lithography system of claim 17, further comprising one or more of the characterizing elements of claims 6-16.

19. Base plate for supporting a vibration isolation system, such as a lithography system, wherein the base plate comprises a bottom side which, in use, faces a foundation, the bottom side being provided with supports or at least being prepared for the mounting supports, wherein the supports are adapted for firmly connecting the base plate to the foundation, such as a concrete foundation block.

The base plate of claim 19, wherein the supports are releasably connected to the base plate.

21. Base plate according to claim 19 or 20, 30, wherein the base plate is a self-supporting base plate.

22. Base plate as claimed in claim 19, 20 or 21, wherein the base plate comprises an upper side which, in use, faces the system, wherein the upper side comprises one or more mounting members or is at least adapted for connecting one or more more mounting members, the mounting members being connectable between the base plate and the system.

The base plate of claim 22, wherein at least one of the mounting members is at least partially aligned with at least one of the supports.

24. Base plate according to one of claims 19 - 23, wherein at least one of the supports is provided with anchoring elements on a side remote from the base plate.

25. Base plate as claimed in any of the claims 19-24, wherein the plate is provided with holes with a threaded insertion element which is fixed therein for connecting a support and / or mounting member to the base plate.

26. Base plate according to any of claims 19-25, further comprising one or more of the characterizing elements of claims 11, 14, 15 or 16. -o-o-o-o-o-o-o-o-9005374