Abstract: It is to provide a photomask substrate which has a low birefringence and with which polarized illumination can be employed or immersion exposure can be carried out. A photomask substrate made of a synthetic quartz glass to be used for production of a semiconductor employing a light source having an exposure wavelength of at most about 200 nm, which has a birefringence of at most 1 nm/6.35 mm at the exposure wavelength, and of which the amount of decrease in light transmittance is at most 1.0% as a difference in light transmittance at a wavelength of 217 nm, between before and after irradiation with Xe excimer lamp with an illuminance of 13.2 mW/cm2 for 20 minutes.

Abstract: A structure for attaching a pellicle to a photomask, the pellicle comprising a pellicle frame and a pellicle sheet attached to an opening portion formed in the pellicle frame, wherein at least a portion of the pellicle frame surface in contact with the photo-mask has a direct contact with the photo-mask without interposing an adhesive.

Abstract: A pellicle formed by bonding a pellicle membrane composed of synthesized glass on a pellicle frame by an adhesive wherein a light shielding member for shielding ultra-violet rays irradiated to the adhesive is provided at a portion where the pellicle membrane is bonded to the pellicle frame, whereby the adhesive for bonding the pellicle membrane to the pellicle frame is prevented from being deteriorated due to the irradiation of ultra-violet rays for cleaning.

Abstract: A structure for attaching a pellicle to a photomask, the pellicle comprising a pellicle frame and a pellicle sheet attached to an opening portion formed in the pellicle frame, wherein at least a portion of the pellicle frame surface in contact with the photo-mask has a direct contact with the photo-mask without interposing an adhesive.

Abstract: It is characterized by having a pellicle sheet made of a synthetic quartz glass having an OH group concentration of at most 100 ppm and containing substantially no oxygen deficient defect. It is particularly preferred that the OH group concentration is at most 10 ppm, and the internal transmittance is at least 80%/cm at a wavelength of 157 nm.

Abstract: A pellicle formed by bonding a pellicle membrane composed of synthesized glass on a pellicle frame by an adhesive wherein a light shielding member for shielding ultra-violet rays irradiated to the adhesive is provided at a portion where the pellicle membrane is bonded to the pellicle frame, whereby the adhesive for bonding the pellicle membrane to the pellicle frame is prevented from being deteriorated due to the irradiation of ultra-violet rays for cleaning.

Abstract: A container for accommodating an optical article made of synthetic quartz glass includes synthetic resin as a base material, and a coating film provided on a substantially entire area of at least an inner surface thereof, the coating film being substantially impermeable to a gas evolved from the synthetic resin as the basic material of the container.