Abstract: An X-ray transmitting homogeneous membrane suitable for use in a mask for X-ray lithography is disclosed which compositely consists of silicon carbide and silicon nitride in a specified molar proportion. The membrane can be prepared by depositing a film of a homogeneous composite of silicon carbide and silicon nitride on a silicon wafer as a substrate by sputering using a target which is also a sintered composite material of silicon carbide and silicon nitride. As compared with membranes of silicon carbide alone or silicon nitride alone, the inventive membrane is advantageous in respect of the high resistance against high-energy irradiation, chemicals and moisture as well as in respect of high visible-light transmission, especially, when the tensile stress within the membrane is in a specified range.

Abstract: Proposed is a high-precision X-ray lithographic mask blank with reinforcement free from warping or distortion. The mask blank is an integral body comprising: (a) a frame made from a silicon wafer; (b) a membrane of an X-ray permeable material such as silicon carbide adhering to and supported by one surface of the frame; and (c) a reinforcing member made from a single crystal of silicon adhesively bonded to the other surface of the frame with (d) a layer of silicon oxide intervening between the frame and the reinforcing member. The mask blank can be prepared in a process of first forming a layer of silicon oxide on the surface of the silicon wafer and/or reinforcing member prior to deposition of the X-ray permeable film on the silicon wafer and heating them together at a temperature of 800.degree. C. or lower while they are in direct contact with each other with the silicon oxide layer intervening therebetween.

Abstract: In a process for the deposition of a film of an inorganic substance such as silicon carbide on the surface of a substrate such as a silicon wafer by the method of sputtering, as in the process for the preparation of a membrane to serve as an X-ray lithographic mask, using a target disc and a substrate disc held in parallel to each other, uniformity in the internal stress of the deposited film can be improved by displacing the target or the substrate relative to each other during the sputtering procedure in the direction parallel to the surface of the target or substrate in a distance of at least 1 mm.

Abstract: The inventive method provides a membrane for X-ray lithography compositely composed of silicon carbide and silicon nitride having high performance in respect of stability against high energy beam irradiation and transparency to visible light. The method comprises depositing a composite film of a specified SiC:Si.sub.3 N.sub.4 molar proportion by sputtering on a silicon wafer as the substrate under such conditions that the thus deposited film is under a compressively stressed state, annealing the substrate bearing the composite film deposited thereon at a specified temperature so as to bring the composite film under a tensile internal stress and then removing the substrate by etching leaving a frame portion.

Abstract: The inventive method provides a silicon carbide membrane for X-ray lithography having high performance in respect of stability against high energy beam irradiation. The method comprises depositing a silicon carbide film by sputtering on a silicon wafer as the substrate under such conditions that the thus deposited film is under a tensile stress in a specified range by keeping the substrate at a temperature higher than 500.degree. C. The thus deposited silicon carbide film is at least partly crystalline and the crystallinity thereof can be defined by the sharpness of a peak in the X-ray diffraction diagram of the membrane which can be assigned to the (1 1 1) plane of the crystalline silicon carbide.

Abstract: A photoacoustic imaging method comprises the steps of using modulated light of two different modulation frequencies to illuminate an object to be observed, so that an image of only a region of a specified depth within the object is obtained based on the difference between two photoacoustic signals separately detected by an acoustic sensor.