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Optical Instruments
The 3D Deflectometry Project
Introduction
European citizens are intense users of Information and Communication Technology (ICT) products and services such as Personal Computers, Lap top computers, GSM telephones, electronics in medicine, home entertainment, internet, etc. It is seen as normal that the quality of this type of products, increases remarkably every few years for the same price (factor ~2 per 3 years). The basis of such progress is for a large part due to fast progress in the quality of the components used in ICT, such as integrated circuits, their interconnection and LCD displays. The semiconductor industry is preparing for further reduction of smallest detail in integrated circuits, down to 130nm. This requires assessment of absence of waviness and steep gradients with 10nm precision over up to 300mm diameter wafers. Control of production, in order to avoid scrap production, requires fast in-line 3D topography measurement instrumentation. Such equipment is technically by far not feasible at present. The situation in LCD production is similar: required in line production control of 3D topography of LCD glass is now by far not technically feasible. Further progress in the production of IT products and services for the Information Society requires a major innovation in instrumentation for in line control of 3D topography of semiprocessed silicon wafers and of LCD glass. 3D deflectometry has the potential for such innovation in instrumentation for measuring 3D topography. Deflectometry measures highly accurate local slopes on a surface. Topography information is derived by numerical integration.Objectives
Objectives of the project are to develop a new 3D-topography measurement technology by means of deflectometry. The feasibility of the new method will be demonstrated by producing a functional model during the project. Innovation of the project will be in the following areas:
- Opto-mechanical design: it is challenging to design a measurement instrument that is robust and can produce contactless 3D topographies by optical/mechanical scanning with an accuracy of 10 nm. Special attention has to be paid to realize a stable set-up;
- Software design: algorithms that retrieve surface shape information from measured slope data in 3D have to be redeveloped completely;
- Data representation: 3D surface data have to be represented in an adequate form to the user. To prove the feasibility, the project is limited to flat and slightly curved surfaces, but can be extended to aspherical surfaces as well later.
More detailed information on the project objectives is given on the following pages: