The development of MEMS comprises the structural design as well as the definition of an appropriate manufacturing
process. Technology constraints have a considerable impact on the device design and vice-versa. Product
design and technology development are therefore concurrent tasks. Based on a comprehensive methodology the
authors introduce a software environment that links commercial design tools from both area into a common design
flow. In this paper emphasis is put on automatic low threshold data acquisition. The intention is to collect
and categorize development data for further developments with minimum overhead and minimum disturbance of
established business processes. As a first step software tools that automatically extract data from spreadsheets
or file-systems and put them in context with existing information are presented. The developments are currently
carried out in a European research project.
The development of micro and nano tech devices based on semiconductor manufacturing processes comprises
the structural design as well as the definition of the manufacturing process flow. The approach is characterized
by application specific fabrication flows, i.e. fabrication processes (built up by a large variety of process steps
and materials) depending on the later product. Technology constraints have a great impact on the device design
and vice-versa. In this paper we introduce a comprehensive methodology and based on that an environment
for customer-oriented product engineering of MEMS products. The development is currently carried out in an
international multi-site research project.
Product engineering of micro and nano technology (MNT) devices differs substantially from product engineering
in more traditional industries. The general development approach is mostly bottom up, as it centers around
the available fabrication techniques and is characterised by application specific fabrication flows, i.e. fabrication
processes depending on the later product. In the first part of this paper we introduce a comprehensive customer-oriented
product engineering methodology for MNT products that regards the customer as the driving force
behind new product developments. The MNT product engineering process is analyzed with regard to application-specific
procedures and interfaces. An environment for the development of MNT manufacturing processes has
been identified as a technical foundation for the methodology and will be described in the second part of this
The development of MEMS devices differs substantially from product engineering methods used in more traditional
industries. The approach is characterized by a close customer involvement and product specific fabrication
processes. A large number interdependencies between device design on the one hand and manufacturing process
development on the other hand make product engineering in the MEMS area a rather tedious and complicated
task. In this paper we discuss a comprehensive customer-oriented MEMS product engineering methodology.
Both MEMS design and fabrication process development are analyzed with regard to procedures and interfaces
used in order to develop an appropriate CAD support either in terms of existing tools or by specifying individual
tools to be implemented. The manufacturing process development is part of this holistic approach and is
supported by a CAD environment for the management and the design of thin-film MEMS fabrication processes.
This environment has been developed by the authors and became recently commercially available.
Thin film fabrication processes for MEMS are characterized by a variety of different process technologies and
materials. Unlike in microelectronics the MEMS fabrication process is in most cases application specific and
therefore integral part of the application design. Discovering the correct combination of process steps, materials
and process parameters usually requires many expensive and time consuming experiments. This paper presents a
new software system that supports the MEMS device and process designers in managing their process knowledge
and in verifying their fabrication processes in virtual fabrication environment, thus reducing the number of real
world experiments to a minimum.
A new non-volatile memory technology for embedded memory applications is described. The technology uses one
cantilever per cell with two stable states to store information. The two stable states are either stuck down to a landing
electrode or not. Because the cantilever and landing electrodes are conducting, each cantilever can be read easily by
measuring the contact resistance between the two. The cantilever stays in the 'on' state due to short range attractive
forces at the contact including metal-to-metal bonding and Van der Waals forces. Using standard CMOS processing
equipment and materials the cantilevers are designed to switch at the native voltages found in micro-controllers, making
this technology an attractive alternative to other forms of embedded non-volatile memory as it reduces the memory block
area by eliminating the requirement for charge pumps. With scaling of the cantilever geometries, the switching speed
drops to below 100ns making it very much faster to program and erase than FLASH and SONOS devices. The high
activation energies associated with adhesion ensure that the technology is reliable over a wide temperature range. In
this paper we discuss how the cantilevers are encapsulated in a wafer scale CMOS process and how the resulting microcavities
are qualified. We will discuss how the contact adhesion forces are modeled to give controllable erasure of the
cantilever into the 'off' state.
Fabrication processes for MEMS are characterized by a variety of different process technologies and materials.
Unlike in microelectronics the fabrication process is relevant to all design stages within the design flow. Discovering
the correct combination of process steps, materials and process parameters usually requires a large number
of experiments. This paper presents a new software system that supports the MEMS designers in managing their
process knowledge and in performing virtual experiments using SILVACO TCAD tools.
In MEMS design many different fabrication techniques and materials are involved and the strong dependency between microstructure and fabrication process leads to application specific fabrication processes. A comprehensive management of process knowledge is required to take into account the various interdependencies and constraints occurring within a MEMS fabrication process. This paper presents an environment for the management of process knowledge and provides support for the design and verification of application specific fabrication processes.
A MEMS process design, development and tracking system is presented. It allows the specification of processes for specific applications and the tracking of the development procedures. The system consists of several components. Based on a comprehensive database that is able to store and manage all process related design constraint data as well as development related data linked to the fabrication process itself. A design model representing the relations between application specific fabrication processes and the structural design flow will be presented. Subsequently the software environment, called <i>PROMENADE</i>, will be introduced meeting the requirements of this process approach.
A design model representing the relations between application specific fabrication processes and the structural design flow will be presented. Subsequently a MEMS process design, simulation and tracking system, called PROMENADE, is introduced. It allows the specification of processes for specific applications, the simulation and the tracking of the development procedures.
MEMS fabrication processes are characterized by a numerous useable process steps, materials and effects to fabricate the intended microstructure. Up to now CAD support in this domain concentrates mainly on the structural design (e.g. simulation programs on FEM basis). These tools often assume fixed interfaces to fabrication process like material parameters or design rules. Taking into account that MEMS design requires concurrently structural design (defining the lateral 2-dim shapes) as well as process design (responsible for the third dimension) it turns out that technology interfaces consisting only of sets of static data are no longer sufficient. For successful design flows in these areas it is necessary to incorporate a higher degree of process related data. A broader interface between process configuration on the one side and the application design on the other side seems to be needed. This paper proposes a novel approach. A process management system is introduced. It allows the specification of processes for specific applications. The system is based on a dedicated database environment that is able to store and manage all process related design constraints linked to the fabrication process data itself. The interdependencies between application specific processes and all stages of the design flow will be discussed and the complete software system PRINCE will be introduced meeting the requirements of this new approach.
Based on a concurrent design methodology presented in the beginning of this paper, a system is presented that supports application specific process design. The paper will highlight the incorporated tools and the present status of the software system. A complete configuration of an Si-thin film process example will demonstrate the usage of PRINCE.
A process management and development system for MEMS design is introduced. It allows the specification of processes for specific applications and the tracking of the development procedures. The system is based on a dedicated database environment that is able to store and manage all process related design constraints and development related data linked to the fabrication process data itself. The interdependencies between application specific processes and all stages of the design flow will be discussed and a software system will be introduced meeting the requirements of this new approach. Although initially dedicated to microsystem processes this environment may also support nanoelectronic fabrication technologies.
New microfabrication technologies in the MEMS domain require novel approaches in computer aided design. Process issues in these technologies affecting the design are becoming increasingly important and Process information held in static design rule sets will be no longer sufficient. This paper describes the methodology and the implementation of a process management system that supports the designer in configuring application specific process flows with predictable properties.
Taking into account the tendency towards higher integration based on sophisticated technologies in microelectronics or the use of specific process steps for the realization of MEMS it becomes evident that the impact of properties and parameters from fabrication processes are getting more and more important. For long the interface between the design domain and the process domain was simply expressed in design rules sets. With the use of high resolution and new IC technology steps the interface gets more complex. As far as MEMS are concerned the technology issues are too dominating for fixed interfaces to the design. Novel approaches are necessary to support future design tasks in the area covered by process development on the one hand and application/structure design on the other hand, considering structural design specifications as well as process flow requirements. This paper describes the development of a process design and management environment that supports process engineers and designers to determine valid process step sequences for specific applications and to derive all characterization data from process flows that are relevant for design stages. This environment (acronym PRINCE) is developed in cooperation with a major European MEMS foundry. It is based on a common data base where all process steps and their characterizations as well as derived rules are stored. Users are able to compose process flows on a graphical editor. Consistency violations such as missing or wrong placed process steps within a complete process flow will automatically be detected. Future work will integrate algorithms to optimize process flows.
Microfabrication technologies require adequate design methodologies since there is a strong interaction between the shape or the layout of microstructures and their fabrication process sequence. Both areas are subject of design. This paper gives an overview over the different design methodologies in design of microstructures focusing on fabrication process design. To derive the novel design models, the different approaches in digital, analog, mixed-signal, and MEMS design are described. The second part of the paper addresses the state of the art in process flow design tools. Eventually a new software environment based on the design models is presented that is based on current software technologies and platform independent programming
With this paper a new approach for MEMS design tools will be introduced. An analysis of the design tool market leads to the result that most of the designers work with large and inflexible frameworks. Purchasing and maintaining these frameworks is expensive, and gives no optimum support for MEMS design process. The concept of design assistants, carried out with the concept of interacting software components, denotes a new generation of flexible, small, semi-autonomous software systems that are used to solve specific MEMS design tasks in close interaction with the designer. The degree of interaction depends on the complexity of the design task to be performed and the possibility to formalize the respective knowledge. In this context the Internet as one of today's most important communication media provides support for new tool concepts on the basis of the Java programming language. These modern technologies can be used to set up distributed and platform-independent applications. Thus the idea emerged to implement design assistants using Java. According to the MEMS design model new process sequences have to be defined new for every specific design object. As a consequence, assistants have to be built dynamically depending on the requirements of the design process, what can be achieved with component based software development. Componentware offers the possibility to realize design assistants, in areas like design rule checks, process consistency checks, technology definitions, graphical editors, etc. that may reside distributed over the Internet, communicating via Internet protocols. At the University of Siegen a directory for reusable MEMS components has been created, containing a process specification assistant and a layout verification assistant for lithography based MEMS technologies.