VTT Technical Research Centre of Finland has developed a method for the
manufacture of thin film transistors using a roll-to-roll technique only. Thin
film transistors can now be manufactured using roll-to-roll techniques, such
as printing, for the deposition of patterns on the substrate layer of film.
This is set to expand the range of electronic components and products, while
slashing their production costs. Thin film transistors are more suitable than
traditional silicon chip transistors for applications such as large-surface
display screens, certain sensor applications, toys, games and smart cards.
A transistor is a basic electronic component which can function as an
electrical switch, an amplifier or a memory element. For transistor
technology, roll-to-roll fabrication techniques have a range of advantages.
These include the possibility to use large surface areas, as well as
mechanical flexibility, transparency and low production start-up costs. Until
now, production of thin film transistors has typically been only partly based
on roll-to-roll techniques, resulting in fairly high mass production costs.
As the technology matures, it is predicted that the markets for thin film
transistors will grow from their current value of three million dollars to
around 180 million over the next decade.
VTT has developed thin film transistor production techniques as part of the
EU-funded POLARIC research project. With the aid of a special self-aligning
technique, the method under development eliminates the challenge of aligning
the patterns in the different thin film layers accurately against each other
in the roll-to-roll process. In addition, the pattern size for transistor
components is pushed to the limit of minuteness possible for printing
techniques; this means patterns of a few dozen micrometres at their tiniest.
Producing thin film transistors using a self aligning roll-to-roll
manufacturing process is one of the few demonstrations internationally so far.
Initial experiences of this thin film transistor manufacturing process are
promising. It provides VTT with the ideal basis for using the process to test
thin film materials as they develop, to develop more complex electronic
circuits and to trial various applications. The goal is to keep developing the
technology until it matures enough to provide a springboard for new business
activities. VTT is now seeking companies interested in developing applications
based on printed thin film transistors.