Preface

Today the cost-effective replication of components in polymers is fundamental for the mass fabrication of a wide range of products, especially in the consumer market. The replication processes—especially the process of injection molding—are highly automated and optimized for the replication of products characterized by a large bandwidth of forms and dimensions. With the development of microsystem technology and, further, of nanotechnology, replication was to be faced with a new challenge—the replication of structures in the micro or even nano range. This requirement of cost-effective replication is underlined by the fabrication costs of micro and nanostructures and fuses on the complexity of the fabrication processes. The established replication technologies optimized for structures in macroscopic dimensions cannot be used for the replication of structures in microscopic dimensions without any modifications. The technological requirements are different, because a decreasing structure size is characterized by an increasing relation between surface and volume of a structure. Further, the structure sizes require replication processes and technologies based on high-precision manufacturing and precise control, which makes it necessary to adapt established techniques or to develop new molding techniques. Today hot embossing is, besides the micro injection molding process, one of the common replication technologies for the replication of microstructures in polymers. With the upcoming of nanoimprint technologies the importance of the embossing technique increases. The process of thermal nanoimprint and the hot embossing process are especially characterized by similar process steps.

This book will give the reader a fundamental background on the different aspects of hot embossing. Beginning first with an overview of the different replication technologies, the diversity of the hot embossing process for the fabrication of micro- and nanostructures will underline the flexibility of this replication technique. The implementation of this diversity will be supported by a technology of hot embossing machines, tools, and microstructured mold inserts. The fundamental background refers also to the theoretical knowledge of polymers as molding materials and also in the fundamentals of a theoretical process analysis. The versatility of hot embossing will be illustrated by applications where the process plays an important role in the fabrication line.

Hot embossing and thermal nanoimprint undergo constant development. The limits regarding structure size, molding area, complexity of the structures, and process times are not fixed. New applications requiring mass production will shift the limits in the future. With a fundamental theoretical knowledge of the hot embossing process and its technology, combined with practical experience, the reader may be part of further developments of this technique and pave the way to new applications. If the book can make a contribution to this, its aim was achieved.