METHOD OF CONTROLLING QUALITY OF PHOTOMASK ALIGNMENT WHEN CONDUCTING DOUBLE-SIDED PHOTOLITHOGRAPHY ON SILICON WAFER Russian patent published in 2025 - IPC H01L21/66 

FIELD: measuring.

SUBSTANCE: use to control the quality of photomask alignment when conducting double-sided photolithography on a silicon wafer. Method of photomask alignment quality control during double-sided photolithography on a silicon wafer includes placing a silicon wafer on a microscope table, operating in the visible and infrared regions of the spectrum and configured to transmit an image to a computer with software for processing the obtained images, wherein the table is equipped with an infrared radiation source, selection of a lens with fivefold magnification on the microscope, aiming the microscope lens at the double-sided photolithography mark from the front side of the plate so that the double-sided photolithography mark is located at the centre of the lens, the subsequent selection on the microscope of the lens with twenty-fold magnification, aiming at the double-sided photolithography mark from the front side of the plate and fixing the mark contours in the software, switching the microscope to infrared mode, switching on the infrared radiation source, aiming at the mark from the back side of the plate due to the transparency of the silicon substrate in infrared light, fixing the mark contours in the software, measuring the difference in their location, at that, to ensure accuracy of control of two-sided alignment of marks on photomasks of silicon wafer, marks on front and back sides of wafer are made in different tonality, wherein the length and width of the mark on the front side of the silicon wafer made in the light tone is greater by 1 mcm than the length and width of the mark made in the dark tone on the back side of the wafer.

EFFECT: providing the possibility of simplifying the method for quality control of photomask alignment during double-sided photolithography on a silicon wafer and increasing the accuracy of photomask alignment during double-sided photolithography on a silicon wafer.

1 cl, 4 dwg