| 摘要 |
PURPOSE:To prevent the adhesion of dust on a lower photomask and improve the yield of a device by providing a mask holder with a clean air flowing device. CONSTITUTION:A photomask 2 is previously set to a lower mask holder 1 of a projection type both surface exposure machine. The holder 1 is set to a holding tool 3 with a device 6 flowing clean air to the front from the back. Only the front of the device 6 is opened, and the circumference of the holding tool 3 is covered with the device 6. According to this constitution, dust does not infiltrate from the circumference of the holding tool during exposure, defective exposure is not generated and the yield of a device is improved. |
