Soft lithography, a known technique for transferring micro patterns onto a surface of a substrate serving as the basic structure for integrated circuits, (see also Xia, Y.; Whitesides, G. M. Angew. Chem. Int'l. Ed. 1998, 37, 550) relies on a stamp to bring a reactant in contact with a substrate.
Stamp materials in soft lithography are exposed to capillary forces, self-adhesion, and mechanical stresses during printing. These stresses before or during printing can deform the stamp or cause parts of it to collapse, which leads to defective and inaccurate prints. Most of the work on contact printing has been done using Sylgard 184 manufactured by Dow Corning Corp., Midland, Mich., USA, a commercially available thermo-cured Siloxane polymer, whose structures smaller than 1 μm tend to merge or collapse during inking and printing (see also Biebuyck, H. A.; Larsen, N. B.; Delamarche, E.; Michel, B. IBM J. Res. Develop. 1997, 41, 159). 
The diverging demands given by conformability, high pattern stability, small thermal or mechanical expansion, and runout cannot be met by one material alone but require layered structures. A practical method to compensate partially for insufficient dimensional and mechanical stability of polymeric materials is to mold the stamp polymer on top of a rigid glass backplane (see also the article of Biebuyck et al. mentioned above). Such hybrid stamps have a better overall accuracy, but stresses generated upon cooling of the polymer layer cast against rigid supports and the process of printing itself can still account for small non-uniform distortions. Very thin polymer layers (<0.1 mm) reduce this problem but suffer from a severely reduced capability to compensate substrate topography and stamp thickness inhomogeneities. Because of this limitation they are applicable only for lithographies on flat substrates.
Stamps are the key elements in soft lithography because they carry the pattern on their surface and are capable of conformal contact during printing. Soft lithography requires adaptation of the stamp to a potentially uneven substrate but collapse, deformation, and runout must be avoided simultaneously. In fact a careful balance between desired and undesired deformation has to be maintained.
In particular the implementation of mechanized large area printing is crucial for the applicability of soft lithographies in a high-volume manufacturing environment. In this case it is highly important to transfer the pattern of the stamp—in most applications the stamp is inked with a thin layer of chemicals—precisely onto the surface of a substrate which may be of a flat or from flat differing nature. It is a highly sophisticated task to print large area substrates with invariable high quality all over their surfaces.
The development of stamps useable for large area printing leads to thin film hybrid stamps having a stiff backplane that dominates the lateral stability and a thin soft patterned layer as disclosed in WO 97/06012. This known hybrid stamp structure for lithographic processing comprises an elastically deformable layer for accommodating unevenness of the surface of a substrate and of the stamp structure itself, and a patterned layer in which a lithographic pattern is engraved. The stamp structure is further enhanced by a third layer, which acts as rigid support for the stamp, thus preventing an undesired deformation of the stamp. As opposed to the hybrid stamp concept disclosed in WO 97/06012 the deformable layer is not placed in between the pattern carrying layer and the backplane but on the other side of a thin backplane that is partially flexible perpendicular to its plane.
A method of using the stamp as described before for printing surfaces is disclosed in WO 97/06013. The document describes a process for producing lithographic features in a substrate layer by lowering the stamp carrying a reactant onto a substrate, confining the subsequent reaction to the desired pattern, lifting said stamp and removing the debris of the reaction from the substrate. Preferably, the stamp carries the pattern to be etched or depressions corresponding to such a pattern.
Nevertheless a couple of problems still remain for producing large area printed structures on substrates using soft lithography technique:                The larger the to be printed area the greater the possibility of inclusion of air bubbles in the contact plane between the patterned stamp layer and the to be printed surface. For instance, printing of a flat full wafer having a slight bow causes inclusion of air bubbles frequently leading to zones of failed printing due to missing contact between the stamp and the wafer surface.        Inhomogeneities of the thickness of the thin film hybrid stamp due to chemical or thermal shrink and tolerances in the printing tool cause uneven load on different areas of the stamp. This leads to collapse of patterns and/or sagging.        In connection with the before mentioned disadvantage there exists no possibility for control or monitoring the actual surface-distributed load acting onto the stamp while printing to locate printing zones in which ceiling or bottom load limits are exceeded or not even reached. Using well-known force transducers in combination with the printing tool only the overall load can be detected and controlled. Monitoring local force distribution at the contact layer between the stamp and surface however could allow a post-print analysis thus improves the process of soft lithography noticeably.        For providing an accurate alignment between the patterned layer of the stamp and the surface to be printed difficulties can arise in printing large surfaces due to inherent differences of expansion or stretch conditions of the contacting surfaces. Repeated conformal printing of different sets of structures onto a surface inevitably leads to deviations of positioning the stamp towards the surface between each printing event.        Disturbing print contacts between the stamp and the substrate appear in areas of the patterned layer where no structured pattern is provided. If the distance of two neighboring patterned structures is large enough sagging of the receded patterned layer appears from a distinct load of the stamp leading to unintentional prints.        
The object of the present invention is to enhance a thin film hybrid stamp in such a way that mechanized large area printing should be possible. The printing results of such a soft lithographic process using the inventive stamp device should be of high quality even in case the contacting plane between the stamp and the substrate's surface differs from a precise smooth and even plane.
It is a further object of the invention to avoid disadvantages as characterized before. The inventive stamp device itself as well in combination with advantageous additional features should be the basis for a precise transfer technique of micron and sub micronscaled structures onto a plane or curved surface.