Abstract: The present invention suppresses decreases in the volumes of the patterns which have been formed on the surfaces of semiconductor samples or of the like, or performs accurate length measurements, irrespective of such decreases. In an electrically charged particle ray apparatus by which the line widths and other length data of the patterns formed on samples are to be measured by scanning the surface of each sample with electrically charged particle rays and detecting the secondary electrons released from the sample, the scanning line interval of said electrically charged particle rays is set so as not to exceed the irradiation density dictated by the physical characteristics of the sample. Or measured length data is calculated from prestored approximation functions.

Abstract: A vacuum heating furnace comprises a translucent container for retaining a heated object and a heating light source for heating a heated object retained in the translucent container. The translucent container has on its surface a tapered portion to receive transmitted light totally reflected on the inner surface of the translucent container at an angle smaller than a critical angle.

Abstract: A vacuum heating furnace comprises a translucent container for retaining a heated object and a heating light source for heating a heated object retained in the translucent container. The translucent container has on its surface a tapered portion to receive transmitted light totally reflected on the inner surface of the translucent container at an angle smaller than a critical angle.

Abstract: A semiconductor device manufacturing apparatus and its method, measures the amount or chemical composition of reaction products adhering to or deposited on the inside of a processing chamber of the semiconductor device manufacturing apparatus, without exposing the chamber to the air. External light, such as infrared light, is introduced from a light introducing unit into the processing chamber. A light receiving unit provided outside the processing chamber receives light reflected from a specified location inside the processing chamber or light reflected from an arbitrary location inside the chamber. The received light is then subjected to spectrometry or photometry to judge how badly the chamber is contaminated and to judge the state of the process being carried out.