U.S. Philips Corporation

Other

Casparus A H Juffermans

Peter Dirksen

Pierre Hermanus Woerlee

Andreas Hubertus Montree

Aberrations of an imaging system (PL) can be detected in an accurate and reliable way by imaging, by means of the imaging system, a circular phase structure ( ) on a photoresist (PR), developing the resist and scanning it with a scanning detection device (SEM) which is coupled to an image processor (IP). The circular phase structure is imaged in a ring structure ( ) and each type of aberration, like coma, astigmatism, three-point aberration, etc. causes a specific change in the shape of the inner contour (CI) and the outer contour (CE) of the ring and/or a change in the distance between these contours, so that the aberrations can be detected independently of each other. Each type of aberration is represented by a specific Fourier harmonic (Z-), which is composed of Zernike coefficients (Z-), each representing a specific lower or higher order sub-aberration. The new method enables to determine these sub-aberrations The new method may be used for measuring a projection system for a lithographic projection apparatus.

Method of detecting aberrations of an optical imaging system

Aberrations of an imaging system (PL) can be detected in an accurate and reliable way by imaging, by means of the imaging system, a test object having circular phase structure (,) on a photoresist (PR), developing the resis and scanning it with a scanning detection device (SEM) which is coupled to an image processor (IP). The circular phase structure is imaged in a ring structure (,) and each of several possible aberrations, like coma, astigmatism, three-point aberration, etc. causes a specific change in the shape of the inner contour (CI) and the outer contour (CE) of the ring and/or a change in the distance between these contours, so that the aberrations can be detected independently of each other.

Test object for use in detecting aberrations of an optical imaging system

Amorphous or polycrystalline silicon layers are sometimes used in the metallization steps of IC processes, for example as antireflex coatings or as etching stopper layers for etching back of tungsten. A problem is that such a layer cannot be provided by CVD or LPCVD on account of the high deposition temperature which is not compatible with standard Al metallizations. Other deposition techniques, such as sputtering or plasma CVD, often lead to a lesser material quality, a longer processing time per wafer, or a worse step covering. According to the invention, the layer is provided by CVD or LPCVD at a temperature below 500&deg; C. under the addition of Ge. The Ge,Si,layer (,) thus obtained is found to have good properties as regards step covering, optical aspects, electrical aspects, and etching aspects, and is compatible with any Al metallization (,) already present.

Method of manufacturing a semiconductor device

Aberrations of an imaging system can be detected in an accurate and reliable way by imaging, by means of the imaging system, a circular phase structure on a photoresist, developing the resist and scanning it with a scanning detection device which is coupled to an image processor. The circular phase structure is imaged in a ring structure and each of several possible aberrations, like coma, astigmatism, three-point aberration, etc. causes a specific change in the shape of the inner contour and the outer contour of the ring and/or a change in the distance between these contours, so that the aberrations can be detected independently of each other. The new method may be used for measuring a projection system for a lithographic projection apparatus.

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Eindhoven, Netherlands

Casparus A H Juffermans