Abstract:
A device and a method for transferring microstructures from a tool to a substrate which is to be structured. The device and method are intended to align the tool and the substrate in a mutually controlled manner. The device contains supports for the tool and the substrate which can be displaced in an opposing direction in relation to one another, resulting in an alteration of the distance between the tool and the substrate. A measuring system is provided which can be inserted between the supports, for measuring selected locations on at least one measuring plane. The direction of displacement of the supports is aligned vertically in relation to said measuring plane. The measuring system forms a fixed spatial relationship with the tool in a measuring position. The substrate can be aligned in relation to the tool. The method and device can be used for producing microstructured components.

Description:
BACKGROUND OF THE INVENTION 
     a) Field of the Invention 
     The invention relates to the transfer of microstructures from a tool to a substrate which is to be structured, with supports for the tool and the substrate which can be adjusted in relation to one another in a direction resulting in an alteration of the distance between the tool and the substrate. 
     b) Description of the Related Art 
     A device of this type is known, for example, from DE 196 48 844 C1. 
     For transferring microstructures, it is known to press a molding tool into a moldable material, such as for example a layer of thermoplastic material, preferably under a vacuum and at a temperature above the softening temperature of the moldable material and, as a result, to produce three-dimensional structures with structure heights in the range of just a few nanometers up to several hundred micrometers. 
     A device suitable for this purpose, according to DE 196 48 844 C1, is capable of compensating for variations in thickness of molding tools and of moldable materials used, while ensuring high dimensional stability, and of ensuring different molding depths. 
     The device includes a chamber with a chamber part which is fixed to the framework and a chamber part which is adjustable, in which chamber the setting of the pressure and temperature conditions is linked to prescribed values of a force acting on the fixed chamber part. 
     It is disadvantageous in the case of this known device that the location at which the structures are to be transferred into the moldable material cannot be determined. 
     OBJECT AND SUMMARY OF THE INVENTION 
     It is therefore the primary object of the invention to ensure that the tool and the moldable material can be mutually aligned in a manner which can be monitored. 
     According to the invention, the object is achieved by a device for transferring microstructures from a tool to a substrate which is to be structured, with supports for the tool and the substrate which can be adjusted in relation to one another in a direction resulting in an alteration of the distance between the tool and the substrate, in that, for measuring selected locations in at least one measuring plane, in relation to which the direction of adjustment of the supports is directed vertically, a measuring system which can be pushed in between the supports and, when in a measuring position, is in a fixed spatial relationship with the tool is provided, and in that the substrate can be displaced parallel to the measuring plane for alignment with respect to the tool. 
     The support for the tool is contained in a first chamber part and the support for the substrate is contained in a second chamber part of a closable chamber, in which the transfer of the microstructures takes place by molding. 
     The chamber is advantageously designed as a vacuum chamber or can be filled with inert gas. 
     The measuring system includes various optical branches with image fields of different sizes, the magnification of a first optical branch permitting easy searching for the locations to be selected and that of a second optical branch permitting exact measurement of the selected locations in the measuring planes. 
     A transporting device which contains different drives for positions to be moved to one after the other is provided for the pushing in of the measuring system, a first drive undertaking the transport from a first position outside the chamber into a second position in the opened chamber and a second drive moving the measuring system into a position aligned in relation to the tool. The measurement can be performed without hindering the molding. 
     The data ascertained are used for activating a device for displacing the substrate with respect to the tool which is contained in the second chamber part. The device includes two sliding plates which lie one on top of the other, are movable in relation to each other parallel to the plane of the substrate adjustment and of which an upper sliding plate serves as a chamber-closing element. 
     The upper sliding plate can preferably be clamped to the lower sliding plate. 
     The upper sliding plate can, furthermore, support a first part of a heating and cooling unit, on which a securing means for the substrate is fastened. 
     For changing the height of the chamber, the chamber may have side wall parts which provide a seal towards the outside and are themselves adjustable in relation to one another in the direction of the adjustability of the chamber parts. 
     It is advantageous if the tool is enclosed on its circumferential surface by a cylindrical tool holder, which is fastened in the first chamber part to a plate-shaped body. 
     The plate-shaped body may be in connection with a second part of a heating and cooling unit. 
     For removing the molded material from the tool, the tool holder may be enclosed at the lateral surface by a demolding tool, which is displaceable with respect to the tool holder in the direction of the mutual adjustability of the supports for removing the substrate from the tool following the transfer of the microstructures. 
     To ensure great stability over time of individual systems of the device, the measuring system, the displacing device and the first chamber part may contain channels for a temperature-controllable fluid. 
     For establishing the fixed spatial relationship between the measuring system and the tool, hooks for hanging on correspondingly shaped hooks of the first chamber part are fastened to the measuring system in the upper region of the latter. 
     It is also advantageous if the substrate comprises a supporting layer and a moldable material applied to the latter. 
     A tool for transferring structures into the moldable material may also be applied to the supporting layer. 
     The subject matter of the invention also includes a method for transferring microstructures from a tool to a substrate which is to be structured, with supports for the tool and the substrate which can be adjusted in relation to one another in a direction resulting in an alteration of the distance between the tool and the substrate. A positioning, required for the locationally exact transfer of the microstructures, of the substrate which is to be structured with respect to the tool in a plane in relation to which the direction of adjustment of the supports is directed vertically is ascertained by correction values for the positioning, determined by the distance of the microstructure from a mark on the substrate, being formed from measured structure positions of transferred microstructures on a first structured substrate for at least one further substrate to be structured. 
     To increase the positioning accuracy further, on the first substrate the positions of the marks may be additionally ascertained before and after the transfer of the microstructures for forming correction values for the positioning. 
     If the positioning accuracy is to be improved still further, the positions of marks on the substrate holder may be determined as correction values before a substrate is placed onto the substrate holder. 
     Finally, it is also advantageous if, after the molding of each substrate, ascertained positions of the molded microstructures and of the marks are used as correction values for the positioning of the substrate which is to be respectively structured thereafter. 
     With the present invention, the unchangeable spatial arrangement of the tool in relation to the moldable material prescribed in the case of the known technical solutions by the structural design is no longer applicable and their mutual alignment is ensured with high precision by ascertainment and manipulation of the positional relationships. 
     The invention is to be explained in more detail below with reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a basic representation of an installation for molding microstructures, 
     FIG. 2 shows a perspective representation of a measuring system for the positional determination of selected microstructures in a plane, 
     FIG. 3 shows a device for transporting the measuring system into the molding region and out of this region, 
     FIG. 4 shows a device for displacing a substrate to be molded in relation to the tool as an integrated component part of the lower chamber part of the molding installation, 
     FIG. 5 shows a plan view of the device according to FIG. 4, 
     FIG. 6 shows a substrate holder with a substrate resting on it, and 
     FIG. 7 shows the upper chamber part of the molding installation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the case of the molding installation represented in FIG. 1, a load frame  1  supports a part  2  which is fixed to the framework and a part  3  which is adjustable, to which parts an upper flange  4  and a lower flange  5  are fastened. The flanges  4 ,  5  serve for the securing of oppositely lying chamber parts  6 ,  7  of a closable chamber, which in the present exemplary embodiment is designed as a vacuum chamber. Instead of the vacuum chamber, however, a chamber which can be filled with inert gas, for example, is also suitable for molding purposes. 
     With the cooperation of devices not represented, such as a device for force measurement, an evaluating and activating unit and a device for path measurement, the part  3  which is adjustable can be displaced with respect to the part  2  which is fixed to the framework by a drive integrated into the frame  1 , whereby closing and opening of the chamber is made possible. The evaluating and activating unit controls, inter alia, the positioning of the part  2  which is fixed to the framework in relation to the part  3  which is adjustable and serves with the device for force measurement for maintaining a defined force between the part  2  which is fixed to the framework and the part  3  which is adjustable. 
     It is immediately evident to a person skilled in the art that the part  2  which is fixed to the framework and the part  3  which is adjustable can be changed over in their arrangement. 
     A measuring system  8 , to be described in further detail in FIG. 2, is placed in a removable way onto a mobile framework  9 , the underlay  10  of which is fastened to the lower chamber part  7 . The mobility of the measuring system  8  serves the purpose of moving of the latter into the molding region between the two chamber parts  6 ,  7  when the chamber is open and out of it again. Hooks  11  provided in the upper region of the measuring system  8  have at their ends bearing surfaces  12 , which are shaped as a three-point bearing in a way corresponding to hemispherical bearing surfaces  13  on hooks  14 , which are attached to the upper flange  4 . In the hung-in state, a defined positional relationship is established between the measuring system  8  and the upper flange  4 . The lower region of the measuring system  8  has hemispherical aligning elements  15 , which rest on positioning elements  16  in a three-point formation during the moving-in and moving-out operation and align the measuring system  8  on the framework  9  and consequently also in relation to the underlay  10 . 
     The measuring system  8  itself comprises a housing with a bottom plate  17  and a top plate  18 . This housing can be shielded against external influences by a cladding (not represented) on one or more sides. 
     An electrically operated mechanical stage  19 , which can adjust a stage plate  20  parallel to the bottom plate  17  in two directions of movement  21 ,  22  perpendicular to each other is mounted on the bottom plate  17 . 
     The stage plate  20  serves as a support for a measuring microscope  23 , the objective  24  of which has an optical axis O—O directed perpendicularly with respect to the bottom plate  17 . An opening, which cannot be seen in FIG. 2, in the bottom plate  17  ensures the passage of the beam necessary for measuring purposes. The mechanical stage  19  also has in its central region an opening provided for this purpose. The size of the openings ensures unhindered movement of the objective  24  over the entire range of movement in the directions of movement  21 ,  22 . 
     A defined positioning of the mechanical stage  19  takes place with the aid of the equipment software. 
     A low overall height of the measuring microscope  23  is achieved by a beam running in a horizontal direction on the image side with respect to the objective  24 . Following the deflection of the optical axis O—O into a direction parallel to the stage plate, the beam is split into two separate optical branches, each of which contains a CCD camera  25  and  26 , respectively, the position of which is indicated by dashed lines. Different magnifications are used in the optical branches, so that easy searching for microstructures of a viewed object is possible within the image field of the first CCD camera  25 . The magnification of the second branch is made such that exact measurement of the positional relationships of the structures on the object is possible within the image field of the second CCD camera  26 . 
     The measuring microscope  23  operates with an illuminating system for a bright-field/incident-light illumination. The light is provided by means of a first fibre-optic cable (not represented) from a suitable first light source. In addition, a ring light (not represented), which is fed by means of a second fabric-optic cable (not represented) from a second suitable light source, may be attached to the objective  24 . Consequently, the use of a dark-field/incident-light illumination is also possible. 
     It can be seen more clearly from FIG. 2 that the bearing surfaces  12  provided at the hooks  11  have notches  27  aligned in a manner in which they are offset in relation to one another by approximately 120°. Of the hemispherical aligning elements  15  attached to the opposite sides of the bottom plate  17 , one element is fastened on one side and two elements are fastened on the opposite side. 
     A transporting device schematically represented in FIG. 3 comprises the underlay  10 , fastened to the lower chamber part  7 , for receiving the mobile framework  9  and pneumatic drives  28 ,  29 . The first drive  28  serves the purpose of displacing the mobile framework  9  on the underlay  10  from a parking position  30 , lying outside the molding region, into an intermediate position  31 , which already lies within this region. 
     The second drive  29  undertakes the transport from the intermediate position  31  into a hanging-in position  32 , in which the measuring system can be hung by its hooks  11  onto the hooks  14  of the upper flange  4 . 
     The molding installation contains in the lower chamber part  7 , as a further subdevice, a displacing device  33  according to FIGS. 4 and 5, with which a substrate  34  to be molded can be adjusted in a plane perpendicularly with respect to the closing direction of the chamber with respect to a tool denoted in FIG. 7 by  46 . 
     Of two sliding plates  35 ,  36  which lie one on top of the other and are movable in relation to each other parallel to the plane of the substrate displacement, stops  37  are provided for the upper sliding plate  36  and are respectively brought by pneumatic cylinders  38  up against a drive unit  39 , serving as a position encoder, on the sliding plate  35 . Suitable measuring means (not represented) monitor the positions set by the drive unit  39 . The upper sliding plate  36  supports a lower part  40  of a heating and cooling unit, which is necessary for the molding and on which a substrate holder  41  is mounted. On the substrate holder  41 , the substrate  34 , which, as can be seen from FIG. 6, comprises a supporting layer  42  and a moldable material  43 , can be fixed with the aid of spring elements  44 . Lateral stops (not represented) may be additionally provided. Usually, the supporting layer  42  consists of a structured material, such as for example a photolithographically structured ceramic plate or a structured printed-circuit board. 
     If the material  43  is to be molded on both sides, it is possible to replace the supporting layer  42  by a further tool. 
     The upper sliding plate  36  has the additional task of forming the lower termination of the chamber. If the chamber is operated under vacuum conditions, forces for which there are no counteracting forces act on the upper sliding plate  36  due to the atmospheric pressure. To exclude an undesired deformation of the chamber and to ensure a defined relative position of the two sliding plates  35 ,  36  in relation to each other, the upper sliding plate  36  can be pneumatically clamped to the lower sliding plate  35 . The force necessary for this is produced by four pneumatic cylinders  45 , fastened to the lower sliding plate  35 . 
     The force available at the thrust rods of the pneumatic cylinders  45  is transferred by four clamping plates  46  onto the upper sliding plate  36 . 
     According to FIG. 7, the upper chamber part  6  contains the tool  46  which is necessary for the molding and which is enclosed on its circumferential surface by a cylindrical tool holder  47 , fastened on a base plate  48  in a sealed manner. The base plate  48  is in connection with the upper part  49  of a heating and cooling unit, which is fastened to the upper flange  4 . 
     In the present exemplary embodiment, a demolding device  50  is additionally contained in the upper chamber part  6 , of which device an annular demolding tool  51 , which can be displaced parallel to the direction of the adjustment of the chamber parts  6 ,  7 , encloses the tool holder  47 . With an annular groove  52  machined into the base plate  48  and the lateral surface of the tool holder  47 , the demolding tool  51  forms a pressure chamber into which a feed channel for compressed air is led through the base plate  48 . The demolding tool  51 , which has on its end face a projection  53  with a peripheral seal  54 , bears in a sealed manner against the lateral surface of the tool holder  47  and against the outer cylindrical surface of the groove  52 . This ensures that the demolding tool  51  can operate like the piston of a pneumatic cylinder. The range of movement is limited in one direction by the base plate  48  and in the other direction by stops (not represented). Restoring springs (not represented) serve the purpose of bringing the demolding tool  51  back into its position of rest after the feeding of compressed air has been ended. 
     The demolding device  50  serves the purpose of separating the substrate  34  from the tool  46  after the molding process, by the substrate  34  being pressed against the substrate holder  41  by the demolding tool  51 , while at the same time the chamber is open. In addition, compressed air for assisting the detachment can be introduced into the space forming between the substrate  34  and the tool  46 . For this purpose, the space forming is sealed towards the outside. 
     The hooks  14  with the hemispherical bearing surfaces  13  are fastened to the upper flange  4  in a manner in which they are respectively offset by 120°, so that only one is completely visible. An outwardly sealing side wall of the chamber is subdivided into wall parts  55 ,  56 , of which the wall part  55  is attached to the flange  4  and the wall part  56  for closing the chamber comes to rest on a sealing outer region of the lower chamber part  7 . Both wall parts  55 ,  56  are adjustable themselves in relation to each other in the direction of the adjustability of the chamber parts  6 ,  7 , whereby the height of the chamber is variable. 
     When the structures of the tool  46  are being molded into the moldable material  43 , heating and cooling outputs are introduced into the chamber. In order to achieve the accuracies necessary for the adjusted molding operation, in the present exemplary embodiment important parts of the measuring system  8 , of the displacement device  33  and of the upper chamber part  6  are provided with channels for a temperature-controllable fluid, preferably water. 
     For instance, the flange  4  of the upper chamber part  6  has cooling channels  57  passing through it. The hooks  14  are also designed as cooling blocks and contain corresponding channels. Temperature-control blocks  58  are attached to the bottom plate  17  and to the top plate  18  of the measuring system  8 . The sliding plates  35 ,  36  have suitable bores  59  for temperature control. 
     In addition to the function already mentioned, the evaluating and activating unit has a variety of further tasks, such as controlling the mechanical stage  19  and the measuring system  8 , monitoring the positions of the two directions of movement  21 ,  22  of the mechanical stage  19 , evaluating the information from the first and second CCD cameras  25 ,  26  with suitable image processing algorithms and controlling all the pneumatic units as well the drive units  39  and the position monitoring of the latter. The evaluation of the information from the first and second CCD cameras  25 ,  26  can be performed, for example, by the execution of the positioning and molding operation being carried out fully automatically. The evaluating and activating unit may, furthermore, be designed in such a way that the automatic finding of structures within the images of the CCD cameras  25 ,  26  is possible. 
     The following procedure serves for transferring the structures present on the tool  46  to the moldable material  43  with an exactly predeterminable locational position. 
     Once the substrate  34  has been put in place and fixed on the substrate holder  41  with the aid of the spring elements  44 , the chamber is closed by adjusting the chamber parts  6  and  7  towards each other and subsequently evacuated. 
     During this operation, the adjustable part  3  is moved until the tool  46  and the moldable material  43  are touching. The height of the chamber is thereby adapted to the thickness of the moldable material  43  by the adjustability of the wall parts  55 ,  56  with respect to each other. Subsequently, a heating of the tool  46  and the moldable material  43  commences with the aid of the two parts  40  and  49  of the heating and cooling unit. The force effect brought about by a further adjustment of the part  3  and in cooperation with the evaluating and activating unit and also the device for force measurement has the effect of producing a defined pressing force between the substrate  43  and the tool  46 , so that the intended structure transfer takes place. Once the transfer has been completed, a cooling phase and a subsequent admission of air to the chamber follow. With the aid of the demolding device  50 , the moldable material  43  is separated from the tool  46 . 
     For checking the result of the molding operation, the two chamber parts  6 ,  7  are brought to a distance at which not only is the measuring system  8  brought with the aid of the transporting device from the parking position  30  into the hanging-in position  32  suitable for measurement but it is also possible for the substrate  34  to be put into place and removed. 
     The measuring system  8  located in the parking position  30  together with the mobile framework  9  is moved between the two chamber parts  6 ,  7  into the intermediate position  31  by activating the first pneumatic drive  28 . Subsequently, the lower chamber part  6  is adjusted towards the upper chamber part  7 , whereby the transporting device and the measuring system  8  are moved along with it. The three hooks  11  fastened to the measuring system  8  enter the upper chamber part  7  until the notched bearing surfaces  12  are located above the bearing surfaces  13  fastened to the three hooks  14 . The intermediate position  31  is chosen such that the hooks  11  and  14  do not collide with one another. 
     With the aid of the second pneumatic drive  29 , the mobile framework  9  together with the measuring system  8  is brought into the hanging-in position  32 , in which the bearing surfaces  12 ,  13  are located directly one above the other in the vertical direction. By lowering the lower chamber part  6 , the hanging-in operation is completed. 
     Aligned in a defined manner with respect to the tool  46  and in all six lines of freedom, and decoupled from the mobile framework  9 , the measuring system  8  now assumes a measuring position. 
     If, after carrying out measurements, the measuring system  8  is intended to be moved out again from the region between the two chamber parts  6 ,  7 , the mobile framework  9  must firstly be brought into the hanging-in position  32  again. The lower chamber part  6  is adjusted together with the mobile framework  9  towards the upper chamber part  7 , until the aligning elements  15  come to bear against the positioning elements  16 . The coupling of the bearing surfaces  12 ,  13  is discontinued, after which the two surfaces lie one above the other in the vertical direction. While the second pneumatic drive  29  undertakes the transport into the intermediate position  31 , the first pneumatic drive  28  brings the mobile framework  9  with the measuring system  8  into the parking position  30 . When it is moved out into the parking position  30 , the elements to be transported must be in a sufficiently large free space. 
     Since a direct ascertainment of the positional relationships between the tool  46  and the substrate  34  is not possible during the molding operation, it becomes necessary to ascertain the location coordinates of molded microstructures  60  on the moldable material and/or of already existing marks  61  on the supporting layer  42  before and after the molding operation in a trial molding operation preceding the actual molding operation. The respective substrate  34  can then be brought into the required position with respect to the tool  46  on the basis of the location coordinates ascertained, so that positioned molding can be achieved. Structures present on the tool  46  can be transferred to the moldable material  43  with an exactly predeterminable locational position. 
     For carrying out measurements on the microstructures  60 , the marks  61  or on existing marks  62  on the substrate holder  41 , the measuring microscope  24  is firstly brought into the measuring position and subsequently moved with the aid of the mechanical stage  19  over the supporting layer  42  in the directions of movement  21 ,  22 , until the microstructures  60  to be measured, the marks  61  or the marks  62  are sensed. Focusing takes place by raising and lowering the lower chamber part  6 . The data of the images recorded by the microscopic image formation of the CCD cameras  25 ,  26  are made available to the evaluating and activating unit for further processing, in particular for the positioning of the substrate  34  with the aid of the displacing device  33  required for locationally exact molding. 
     For the positioning operation, the clamping between the upper and lower sliding plates  35 ,  36  brought about by the four pneumatic cylinders  45  and the clamping plates  46  is discontinued. It is advantageous if the positional relationships between the marks  61  on the supporting layer  42  and the microstructures  60  of the tool  46  copied into the moldable material  43  are prescribed. The evaluating and activating unit is then capable of calculating the positions to be set of the substrate  34  fastened on the substrate holder  41 , with the assistance of the location coordinates ascertained in the trial molding operation for the microstructures  60  and for the marks  61 , and if need be for the marks  62 , and of performing the activation of the drive units  39 . The drive units  39  define by their setting the position into which the stops  37  for the upper sliding plate  36  are to be brought by the force of the pneumatic cylinders  38 , whereby the substrate holder  41  with the substrate  34  is positioned in the translational coordinates and in the angular position with respect to the tool  46  in a plane parallel to the surface of the sliding plates  35 ,  36 . Following the deactivation of the pneumatic cylinders  38 , the position of the upper sliding plate  36  is initially maintained by the dead weight, before the restored clamping between the upper and lower sliding plates  35 ,  36  stabilizes the position of the upper sliding plate  36 . 
     The set position can be checked by determining the coordinates of the marks  61  on the supporting layer  42  once again in the way already described. If appropriate, a repeated position setting with the displacing device  33  is required. 
     With the solution according to the invention, structures or objects contained on a support can be transferred with very high accuracy to predeterminable locations in a plastically deformable material. This is achieved by measurements of the location coordinates of the transferred structures or objects or of existing structures in the region of the transporting area and subsequent positioning of the region to be structured with respect to the support according to the measured location coordinates. 
     The measurements in the region of the transfer area must take place at such locations that the sensing of all the displacements having an effect on the location coordinates of the transferred structures or objects in a direction perpendicular to the direction of the transfer of the structures or objects is ensured. 
     In the present exemplary embodiment, the following procedures for the execution of the positioned molding operation are envisaged for this purpose: 
     In the simplest form, the basic principle, firstly a first substrate  34  is molded (rough molding) and then the position of the molded microstructures  60  in the moldable material  43  is measured. Once the marks  61  on the supporting layer have been measured with the aid of the displacing device, further substrates  34  to be processed are brought into the position in which the structures of the tool  46  are copied in a subsequent molding operation into the moldable material  43  in a defined distance-based relationship with respect to the marks  61 . The coordinates of the structures  60  of the tool  46  copied into the moldable material  43  are known from the trial molding operation. 
     A first refinement of the positioned molding operation envisages measuring the positions of the marks  61  on thee supporting layer  42  before and after the trial molding of the first substrate  34  and the position of the molded microstructures  60  in the moldable material  43  and using the measurement results for aligning the further substrates  34  to be processed. This in turn involves firstly a determination of the location coordinates of the marks  61  as a basis for the required positioning with the displacing device  33 . It is also advantageous if the structure positions in the supporting layer  42  and in the moldable material after the molding operation are sensed for the respectively following molding operation. This first refinement of the positioned molding achieves the effect that positional deviations of the substrate  34  with respect to the substrate holder  41  occurring in the molding process due to heating, cooling and molding do not act as defects. 
     In a repeated refinement of the molding process, the positions of the marks on the substrate holder  41  are also included. The marks  62  are already measured before the first substrate  34  is put in place. The positions of the marks on the substrate layer  42  before and after the molding operation and the position of the molded microstructures  60  in the moldable material  43  are then measured. 
     In the case of the further substrates  34  to be processed, the position of the marks  62  on the substrate holder  41  before the substrate  34  is put into place and the position of the marks of the supporting layer of the substrate  34  put into place are measured. Subsequently, positioning and molding are performed. After the molding operation, the positions of the marks in the supporting layer  42  and in the moldable material are sensed for the respectively following molding operation. The repeated refinement of the molding process achieves the effect that drift effects between the upper chamber part  6  and the measuring system  8  fixed to it during a measurement, on the one hand, and the lower chamber part  7  with the positioning system  33  fastened to it, on the other hand, do not act as defects. 
     While the foregoing description and drawings represent the present invention, it will be obvious to those skilled in the art that various changes may be made therein without departing from the true spirit and scope of the present invention.