METHOD FOR DETERMINING A DISTANCE BETWEEN TWO BEAMLETS IN A MULTI-BEAMLET EXPOSURE APPARATUS

• Main Author: MEIJER, Jan Andries
• Format: Patent
• Language: English; French; German
• Published: 01.04.2020
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY

The invention relates to a method for determining a distance between two charged particle beamlets in a multi-beamlet exposure apparatus. The apparatus is provided with a sensor comprising a converter element for converting the energy of charged particles into light and a light sensitive detector. The converter element is provided with a sensor surface area provided with a two-dimensional pattern of beamlet blocking and non-blocking regions. The method comprises scanning a first beamlet over the two-dimensional pattern, receiving light generated by the converter element in response to charged particles being part of the first beamlet transmitted through the two-dimensional pattern, and converting the received light into a first signal by means of the light sensitive detector. Then the two-dimensional pattern and the first beamlet are moved relatively with respect to each other over a predetermined distance. Subsequently, the method continues with scanning a second beamlet over the two-dimensional pattern, receiving light generated by the converter element in response to charged particles being part of the second beamlet transmitted through the two-dimensional pattern, and converting the received light into a second signal by means of the light sensitive detector. Finally, the distance between the first beamlet and second beamlet is determined based on the first signal, the second signal and the predetermined distance.