Abstract:
Arrangements of a first body and a second body connected to the first body, as well as related systems and methods, are disclosed. The arrangements, systems and methods can be used, for example, with optical devices, such as in the field of microlithography systems used to manufacture of microelectronic devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority under 35 U.S.C. §119 to German Patent Application Serial Number 10 2006 038 992.1, filed Aug. 21, 2006, which is hereby incorporated by reference.  
       FIELD  
       [0002]     The present disclosure relates to arrangements of a first body and a second body connected to the first body, as well as related systems and methods. The arrangements, systems and methods can be used, for example, with optical devices, such as in the field of microlithography systems used to manufacture of microelectronic devices.  
       BACKGROUND  
       [0003]     It can be desirable in microlithography to maintain a pre-determined relative position of the components of the imaging device (e.g., the optical elements such as lenses, mirrors or grids) with respect to the wafer on which the microelectronic circuits are produced.  
       SUMMARY  
       [0004]     In one aspect, the disclosure generally provides an arrangement that includes a first body having a first contact surface, a second body having a second contact surface, and a material connected to the first and second contact surfaces at a joining location. At least one surface selected from the first contact surface and the second contact surface is divided into a plurality of partial contact surfaces that are at least partly separated from each other. A surface area of each of the partial contact surfaces is less than 15% of a total surface area of the joining location. The arrangement can be used, for example, in a microlithography system that includes an optical device.  
         [0005]     In another aspect, the disclosure generally provides a method that includes connecting a first contact surface of a first body with a second contact surface of a second body via a material at a joining location. At least one surface selected from the first contact surface and the second contact surface being divided into a plurality of partial contact surfaces that are at least partly separated from each other. A surface area of each of the partial contact surfaces being less than 15% of a total surface area of the joining location. The arrangement can be used, for example, in the preparation of a microlithography system that includes an optical device.  
         [0006]     In a further aspect, the disclosure generally provides a first body having a first contact surface, and a second body having a second contact surface. The first and second contact surfaces are connected to the first body at a joining location. A contact surface selected from the first contact surface and the second contact surface is divided into a plurality of partial contact surfaces that are at least partly separated from each other. A surface area of each of the partial contact surfaces is less than 15% of a total surface area of the joining location. The arrangement can be used, for example, in a microlithography system that includes an optical device.  
         [0007]     In some embodiments, the disclosure can provide an arrangement of two connected bodies and/or a method for connecting two bodies, which can (e.g., in a simple manner) allow relatively high (e.g., maximum) stability of the geometry of the two bodies (e.g., even with pressure fluctuations).  
         [0008]     The present disclosure recognizes that a reduction of gas inclusions between the contact surfaces can enhance geometrical stability in the case of pressure fluctuations if at least one of the contact surfaces is divided into a plurality of partial contact surfaces that are at least partly separated from each other so that the surface area of the respective partial contact surface is less than 15% of the total surface area of the joining location. This can allow for relatively small partial contact surfaces that can provide reduced gas inclusions between the contact surfaces.  
         [0009]     It is believed that the comparatively small partial surface area (within which a connection between the two bodies takes place) results in a relatively short distance for gases to escape from the respective joining region between the contact surfaces into the gaps separating the partial contact surfaces, so that the probability of gas inclusions forming is substantially reduced. Relative to the total volume of the two bodies, fewer or smaller gas inclusions can develop as a result, which can lead to lesser deformations with pressure fluctuations in the surrounding atmosphere.  
         [0010]     In some embodiments, the disclosure provide an arrangement of a first body and a second body connected to the first body in the region of a joining location, wherein the first body has a first contact surface and the second body has a second contact surface and the first body and the second body are connected to one another in the region of their contact surfaces. At least one of the contact surfaces in the region of the joining location is divided into a plurality of partial contact surfaces, at least partly separated from each other, wherein the surface area of the respective partial contact surface amounts to less than 15% of the total surface area of the joining location. The connection between the first body and the second body can include a material connection (e.g., an inorganic material connection).  
         [0011]     In certain embodiments, the disclosure provides a method for connecting two bodies in the region of a joining location, wherein a first body with a first contact surface is made available, a second body with a second contact surface is made available and the first body and the second body are connected together in the region of their contact surfaces. At least one of the contact surfaces in the region of the joining location is divided into a plurality of partial contact surfaces, at least partly separated from each other, wherein the surface area of the respective partial contact surface amounts to less than 15% of the total surface area of the joining location.  
         [0012]     Here, if desired, both contact surfaces can be divided accordingly into partial contact surfaces. Manufacturing, however, can be substantially simplified, if the partitioning is only carried out for one of the two contact surfaces. The other contact surface can then be formed in the known way simply as an at least generally coherent surface.  
         [0013]     The partitioning of the contact surface concerned into the partial contact surfaces, at least partly separated from each other, can take place by any suitable mechanism. Thus, suitable recesses, such as grooves, slots or the like, which produce the separation, can be provided in the body concerned. Likewise, however, for producing the separation only one surface structure, deviating correspondingly widely from the surface of the partial contact surfaces, an accordingly heavily roughened surface for example, can also be provided.  
         [0014]     Features and advantages of the invention are in the description, drawings and claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a schematic partial sectional view (along line I-I from  FIG. 2 ) through an arrangement.  
         [0016]      FIG. 2  is a schematic partial sectional view through the arrangement from  FIG. 1  along line II-II from  FIG. 1 .  
         [0017]      FIG. 3  is a schematic partial sectional view through an arrangement. 
     
    
     DETAILED DESCRIPTION  
       [0018]      FIGS. 1 and 2  show an arrangement  101 , which is used as a component of an encoder system in an optical imaging device for microlithography. The arrangement  101  includes a first body in the form of a carrying structure  102  and a second body in the form of a grid element  103 , which are connected together in the region of a first joining location  104  by an optical contacting connection. The grid element  103 , on its side facing away from the carrying structure  102 , has an optical grid, which serves as a reference for the encoder system.  
         [0019]     The carrying structure  102 , on its side facing the grid element  103 , has a first contact surface  102 . 1  in the region of the joining location  104 . Likewise, the grid element  103  in the region of the joining location  104 , on its side facing the carrying structure  102 , has a second contact surface  103 . 1 . The two contact surfaces  102 . 1  and  103 . 1  in a suitable way are correspondingly precisely implemented, so that when they make reciprocal contact an optical contacting connection is obtained in the commonly known way.  
         [0020]     The first contact surface  102 . 1 , in a grid-like manner, is divided into a plurality of partial contact surfaces  102 . 4 , completely separated from each other by depressions or recesses  102 . 2  of the carrying structure  102  running in x-direction and by depressions or recesses  102 . 3  of the carrying structure  102  running in y-direction. In the present example, the recesses  102 . 2 ,  102 . 3  are arranged in a grid-like manner such that the partial contact surfaces  102 . 4  have a substantially square outer contour. Therefore, a kind of checkerboard pattern arises.  
         [0021]     Because of their straight-line arrangement, the recesses  102 . 2 ,  102 . 3  and thus the carrying structure  102  can be produced relatively simply. However, in general, any partitioning of the first contact surface can take place in partial contact surfaces with any other polygonal or curved outer contour. Furthermore, if desired, only the recesses  102 . 2  or only the recesses  102 . 3  can be provided. Individual partial contact surfaces, such as partial contact surfaces in the boundary region of the first contact surface, can be partly connected to one another.  
         [0022]     In contrast to this, the second contact surface  103 . 1  is designed as a substantially even, coherent surface area. As a result, manufacturing of the grid element  103  is simplified. Alternatively or additionally, the second contact surface in a suitable way is divided into corresponding partial contact surfaces.  
         [0023]     The surface area of the respective partial contact surface  102 . 4  amounts to nearly 2% of the total surface area of the joining location  104  in each case. As a result of this comparatively small contact area between the respective partial contact surface  102 . 4  and the second contact surface  103 . 1 , it is ensured that when the optical contacting connection between the carrying structure  102  and the grid element  103  is produced, only comparatively few or small gas inclusions develop between the respective partial contact surface  102 . 4  and the second contact surface  103 . 1 .  
         [0024]     It is believed that this is due, among other things, to the fact that the gas of the atmosphere, which surrounds the two bodies  102 ,  103  when they are joined, owing to the small contact area can escape over a relatively short distance from the region between the respective partial contact surface  102 . 4  and the second contact surface  103 . 1  into an adjacent recess  102 . 2 ,  102 . 3 .  
         [0025]     This can allow for relatively little inclusion of gas between the contact surfaces  102 . 1 ,  103 . 1  is possible. This can advantageously result in a reduction in the deformations of the grid element  103 , which are caused by pressure fluctuations in the atmosphere surrounding the arrangement  101 . Deformations, which result from heating of the arrangement  101  and thus from a thermally-induced increase in the pressure in the gas inclusions, can also reduced.  
         [0026]     In some embodiments, the surface area of the respective partial contact surface amounts to less than about 15% (e.g., less than 5%) of the total surface area of the joining location between the two bodies.  
         [0027]     The recesses  102 . 2 ,  102 . 3 , as mentioned, can be produced relatively simply. Optionally, provision can also be made that the separation of the partial contact surfaces does not need to be achieved by such recesses intruding relatively deeply into a body. It is also possible that this separation is achieved by a corresponding surface structure, for example an accordingly heavily roughened surface, which still allows the gas to escape.  
         [0028]     As is further evident from  FIGS. 1 and 2 , the carrying structure  102  for each partial contact surface  102 . 4  includes a channel in the form of a through-hole  102 . 5 . Optionally, provision can also be made that only a fraction of the partial contact surfaces is provided with a corresponding channel leading to the partial contact surface.  
         [0029]     Through this channel  102 . 5 , a suitable adhesive  105  can be fed into the region of the joining location  104 , after the optical contacting connection between the carrying structure  102  and the grid element  103  has been produced, so that the adhesive  105 , on the one hand, contacts the carrying structure  102  in the channel  102 . 5  and, on the other hand, in the mouth region of the channel  102 . 5 , also contacts the second contact surface  103 . 1 , that is to say the grid element  103 . The adhesive  105  can thus serve to reinforce the optical contacting connection, for example against high forces of inertia, as they occur during high accelerations (e.g., in the case of impacts). Due to its shrinkage, the adhesive  105  can also serve to increase the contacting force between the grid element  103  and the carrying structure  102 . If desired, an inorganic material (e.g. a solder material etc.) may be used instead of the adhesive  105 .  
         [0030]     Furthermore, provision can also be made that all or part of the channels leading to the partial contact surfaces can be provided not in the body having the partial contact surfaces but in the other body.  
         [0031]     As is also evident from  FIG. 2 , the arrangement  101  includes a third body in the form of a second grid element  106 . This second grid element  106  is identical to the first grid element  103  so that reference is made in this respect to the corresponding explanations given above.  
         [0032]     The second grid element  106  is connected in the same way as the first grid element  103  to the carrying structure  102  in the region of a second joining location  107 . For this purpose, it has a third contact surface  106 . 1 , which is connected by an optical contacting connection to the first contact surface  102 . 1  of the carrying structure  102 .  
         [0033]     The first grid element  103  and the second grid element  106  have joining surfaces facing each other, which contact one another in the region of a joint  108 . The two grid elements  103 ,  106  are connected together in the region of the joint  108 . In the present case, they are connected together in the region of the joint  108  by an optical contacting connection. However, any other suitable connection can also be selected. The two grid elements can be glued together.  
         [0034]     The arrangement  101  can include yet further grid elements, so that a comparatively large optical grid poorly susceptible to deformation can be produced in a simple manner. In this case, it is possible, for example, to produce large optical grids, whose surface area lies in the region of 1 m 2  and beyond from still comparatively easy to produce grid elements, whose surface area lies in the region of 0.1 m 2 .  
         [0035]     The carrying structure  102  and the grid element  103  in the present example are made from a material of the same type. This has the advantage that the first coefficient of thermal expansion of the material of the carrying structure  102 , if at all, only differs by a very small amount from the second coefficient of thermal expansion of the material of the grid element  103 .  
         [0036]     Therefore, the coefficients of thermal expansion of the carrying structure  102  and the grid element  103  are well-matched to one another. This can result in relatively little stress as possible occurs between the carrying structure  102  and the grid element  103  due to differing thermal expansion. However, combinations of different materials can also be used.  
         [0037]     The risk of such thermally induced stress can be further reduced, due to the fact that the material of the carrying structure  102  and the grid element  103  has a relatively low coefficient of thermal expansion. Suitable materials here are glass ceramics, Zerodur, ULE or Clearceram, Cordierite or Invar or the like.  
         [0038]      FIGS. 1 and 3  show an  201 , which is used as a component of an encoder system in an optical imaging device for microlithography. The arrangement  201  includes a first body in the form of a carrying structure  202  and a second body in the form of a grid element  203 , which are connected together in the region of a first joining location  204  by an inorganic material connection in the form of a solder joint. The grid element  203  is built like the grid element  103  in  FIGS. 1 and 2 , that is to say, on its side facing away from the carrying structure  202 , it has an optical grid, which serves as a reference for the encoder system.  
         [0039]     The carrying structure  202  likewise is generally similar to the carrying structure  102  in  FIGS. 1 and 2 . Only the channels  102 . 5  of the carrying structure  102  are missing from the carrying structure  202 . The location of the section shown in  FIG. 3  corresponds to the one of the section along line II-II in  FIG. 1 .  
         [0040]     The carrying structure  202  is designed similarly to the carrying structure  102  in  FIGS. 1 and 2 , i.e. in the region of the joining location  204 , on its side facing the grid element  203 , it has a first contact surface  202 . 1 . Likewise, in the region of the joining location  204 , the grid element  203 , on its side facing the carrying structure  202 , has a second contact surface  203 . 1 .  
         [0041]     The two contact surfaces  202 . 1  and  203 . 1  in a suitable way are implemented with sufficient precision, so that between them a solder join can be obtained in the commonly known way as disclosed, for example, by EP 0 901 992 B1 (Holderer et al.) the entire disclosure of which is incorporated herein by reference. In order to connect the carrying structure  202  and the grid element  203 , a film or layer of an additional material in the form of soldering metal  209  is applied between the two contact surfaces  202 . 1  and  203 . 1  in the commonly known way.  
         [0042]     Like the first contact surface  102 . 1  in  FIG. 1 , the first contact surface  202 . 1  in a grid-like manner is divided into a plurality of partial contact surfaces  202 . 4  completely separated from each other by depressions or recesses of the carrying structure  202  running in x-direction and by depressions or recesses  202 . 3  of the carrying structure  202  running in y-direction. In the present example, the recesses  202 . 2 ,  202 . 3  are again arranged in a grid-like manner such that the partial contact surfaces  202 . 4  have a substantially square outer contour. Therefore, a kind of checkerboard pattern also arises here.  
         [0043]     However, in general, any partitioning of the first contact surface can take place in partial contact surfaces with any other polygonal or curved outer contour.  
         [0044]     In contrast to this, the second contact surface  203 . 1  is again formed as a substantially even, coherent surface area. As a result, manufacturing of the grid element  203  is simplified. However, it can be also provided that, alternatively or additionally, the second contact surface is divided into corresponding partial contact surfaces in a suitable way.  
         [0045]     In the present example, the surface area of the individual partial contact surface  202 . 4  amounts to nearly 2% of the total surface area of the joining location  204  in each case. Due to this comparatively small contact area between the respective partial contact surface  202 . 4  and the soldering metal  209 , it is ensured that when the solder join between the carrying structure  202  and the grid element  203  is produced, only comparatively few or small gas inclusions develop between the respective partial contact surface  202 . 4 , the soldering metal  209  and the second contact surface  203 . 1 .  
         [0046]     This is due ultimately, among other things, to the fact that the gas of the atmosphere, which surrounds the two bodies  202 ,  203  when they are joined, owing to the small contact area, can escape over a relatively short distance from the region between the respective partial contact surface  202 . 4 , the soldering metal  209  and the second contact surface  203 . 1  into an adjacent recess  202 . 2 ,  202 . 3 .  
         [0047]     In comparison to the known joining process, wherein comparatively large coherent contact surfaces are used, in this case substantial reduction of such gas inclusions between the contact surfaces  202 . 1 ,  203 . 1  is possible. In an advantageous way, this causes a reduction in the deformations of the grid element  203 , which are caused by pressure fluctuations in the atmosphere surrounding the arrangement  201 . Deformations, which result from heating of the arrangement  201  and thus from a thermally induced increase in the pressure in the gas inclusions, are also reduced.  
         [0048]     In some embodiments, an additional joining material (e.g., soldering metal  209 ) can be present. If the surface area of the respective partial contact surface amounts to less than about 15% (e.g. less than 5%) of the total surface area of the joining location between the two bodies.  
         [0049]     The recesses for separating the partial contact surfaces  202 . 4 , as mentioned, can be produced relatively simply. As, however, it has likewise already been mentioned, provision can be made that the separation of the partial contact surfaces also with this joining method with an additional material does not need to be achieved by such recesses intruding relatively deeply into a body. By contrast, it is also possible that this separation is achieved by a suitable surface structure, for example an accordingly heavily roughened surface, which still allows the gas to escape.  
         [0050]     A further advantage of the connection using an additional material, such as soldering metal  209 , lies in the fact that the additional material can be suitable for levelling out manufacturing tolerances (e.g., geometry and/or position tolerances) of one or both contact surfaces  202 . 1 ,  203 . 1 , as they are shown heavily exaggerated for the first contact surface  202 . 1  in  FIG. 3 , as the result of a varying layer thickness. It is possible in an advantageous way to even out co-planarity deviations of the partial contact surfaces  202 . 4 .  
         [0051]     It is also possible that the grid element  203 , when it is joined, floats on the additional material, here the soldering metal  209 , and can be connected virtually without stresses to the carrying structure  202 .  
         [0052]     In  FIG. 3 , the soldering metal layer  209  with regard to its actual shape in the region of the recesses  202 . 3 , is only illustrated in a highly simplified manner and as an intermittent, that is to say, interrupted layer. However, in some embodiments (e.g., as a function of the characteristics of the soldering metal and the contact surfaces) a continuous layer of solder, which bridges the recesses, can also be provided.  
         [0053]     Also, further grid elements can be connected to the carrying structure  202 , in order to form a large optical grid in conjunction with the grid element  203 . In this case, the grid elements in turn can be connected together in the region of their joint in a corresponding way. They can also be connected via the additional material already used anyway.  
         [0054]     Here, it is thus also possible, for example, to produce large optical grids whose surface area lies in the region of 1 m 2  and beyond from comparatively easy to produce grid elements, whose surface area lies in the region of 0.1 m 2 .  
         [0055]     In place of the solder joint another material connection technique using an additional material (e.g., an inorganic connecting material) can also be selected. This includes so-called low temperature bonding connections, anodic bonding connections and fusion bonding connections etc.  
         [0056]     The carrying structure  202  and the grid element  203  in the present example in turn are made from a material of the same type. This has the advantage that the first coefficient of thermal expansion of the material of the carrying structure  202 , if at all, only differs by a very small amount from the second coefficient of thermal expansion of the material of the grid element  203 .  
         [0057]     Therefore, the coefficients of thermal expansion of the carrying structure  202  and the grid element  203  are well-matched to one another. This has the advantage that as little stress as possible arises between the carrying structure  202  and the grid element  203  due to the differing thermal expansion. However, different materials can also be used.  
         [0058]     The risk of such thermally induced stress is further reduced, due to the fact that the material of the carrying structure  202  and the grid element  203  has a relatively low coefficient of thermal expansion. Suitable materials here are glass ceramics, Zerodur, ULE or Clearceram, Cordierite or Invar etc.  
         [0059]     While certain embodiments have been described, other embodiments are possible.  
         [0060]     As an example, embodiments have been described in which reference bodies for encoder systems were described. However, the disclosure is not limited in this respect, and the concepts and embodiments described herein can be applied in the context of connecting bodies used in other ways.  
         [0061]     As another example, embodiments involving microlithography have been described herein, but the disclosure is not limited in this respect. For example, the concepts and embodiments described herein can be used in connection with other optical applications or imaging methods.  
         [0062]     As known to those skilled in the art, microlithography systems typically include the following elements and operate in the following fashion. A microlithography system typically includes a light source, an illumination system of optical elements (e.g., one or more lenses, one or more mirrors, and/or one other optical elements such as polarizer elements or gratings), a projection objective of optical elements (e.g., one or more lenses, one or more mirrors, and/or one other optical elements such as polarizer elements or gratings) and a wafer stage. The light source typically provides light of an appropriate wavelength. The illumination system typically provides, in an appropriate fashion, the light from the light source to a reticle (commonly referred to as a mask) supported by a reticle stage. The projection objective typically provides, in an appropriate fashion, the light from the reticle to a wafer supported by the wafer stage. The wafer typically includes one or more light sensitive materials at or near its surface with the overall effect being that the light that passes from the light source, through the illumination system, reticle and projection objective, and images a pattern from the reticle to the light sensitive materials(s) at or near the wafer surface.  
         [0063]     U.S. Pat. No. 5,669,997 (Robbert et al.) and DE 197 55 482 A1 (Hangleiter et al.) are incorporated herein by reference.  
         [0064]     Other embodiments are in the claims.