Hitachi, Ltd.

Nippon Telegraph and Telephone Public Corporation

Yoshio Sakitani

Hideo Todokoro

Satoru Fukuhara

Masahide Okumura

Yoshihisa Minamikawa

Shinichi Kato

Isao Ishikawa

Susumu Ozasa

Yasuo Kato

Minpei Fujinami

Kazumitsu Nakamura

Yukichi Ueno

Satoshi Ido

Syobu Saito

Toshiaki Nakata

Yasushi Nakaisumi

An electron beam measuring apparatus for measuring size of pattern on surface of a specimen comprising, an electron gun, an electron lens for focusing the electron beam from the electron gun on the specimen surface, a deflector for deflecting the electron beam, a spot control means for forming a flat edge portion in the electron beam spot, a rotation coil for rotating the electron beam so that the flat portion of the electron beam spot becomes to be perpendicular to the scanning direction of the electron beam, a detecting means for detecting secondary electrons reflected from the specimen surface, and a computer for calculating the size of the pattern based on the secondary electrons from the detecting means. As the flat portion of the electron beam spot is perpendicular to the scanning direction, the size of pattern is measured with high accuracy.

Electron beam measuring apparatus

A position detecting system suitable for the position control of the surface of a workpiece mounted in an electron beam exposure system is disclosed which includes an electrically-driven light source, a first optical system for focusing a light beam from the light source on a workpiece, a position-controlling table for mounting thereon the workpiece, a second optical system for focusing light reflected from the workpiece on a predetermined image surface, a photodetector having a light receiving surface arranged on the image surface, and a negative feedback amplifier for controlling the light source by the output of the photodetector.

Position detecting system

A specimen support comprises a pair of specimen attracting portions each having an electrode on the lower side thereof through an electrically insulating member. The pair of specimen attracting portions is arranged in opposed relation to one side of the specimen to be attracted thereto and is made of semiconductive dielectric material. A voltage is applied between the pair of specimen attracting portions thereby to attract the specimen to the portions electrostatically.

Specimen supporting device

An apparatus for measuring the specimen potential in an electron microscope includes a first grid arranged to enclose a specimen which is to be irradiated with a primary charged particle beam emitted from the electron source of the electron microscope and to which is supplied a voltage sufficient to attract the secondary electrons emitted from the specimen. A second grid supplied with a voltage sufficient to analyze the energy of the secondary electrons which have passed through the first grid is disposed outside the first grid, and a secondary electron detecting arrangement for detecting the secondary electrons which have passed through the second grid is disposed adjacent the second grid. A current detecting arrangement partly for impressing the voltage upon the first grid and partly for detecting the current flowing through the first grid is provided along with a dividing and amplifying arrangement for dividing the output of the secondary electron detecting arrangement by the output of the current detecting arrangement, whereby the potential at said specimen of the electron microscope is measured with increased sensitivity.

Apparatus for measuring specimen potential in electron microscope

In a field emission electron gun including heating means for heating an anode to prevent gas emission from the anode due to bombardment thereof by the electron beam emitted from the cathode, the present invention provides a field emission electron gun including first exhaust means for defining a first chamber including the cathode and for exhausting said chamber to vacuum, and second exhaust means separate from said first exhaust means defining a chamber including said anode heating means for exhausting said chamber to vacuum independently of the first exhaust means. This construction makes it possible to maintain the chamber including the cathode constantly in the high vacuum state.

Field emission electron gun with anode heater and plural exhausts

A field emission electron gun including a cathode, a control electrode which is disposed in the vicinity of the cathode, an anode which is disposed for accelerating electrons emitted from the cathode, and a source of a D.C. voltage to be applied between the cathode and the anode. Also, there is provided a switching arrangement capable of changing-over a potential of the control electrode between ground potential and a potential of the cathode, and an arrangement capable of varying relative positions of the cathode and the control electrode.

Field emission electron gun

A floating piece is provided between a fixed base and a movable plate which are arranged in parallel spaced relationship, the floating piece being engaged with the fixed base for movement only in the X direction and being engaged with the plate for movement only in the Y direction. First counter piezoelectric members capable of expanding or contracting in the X direction in response to an applied voltage and second counter piezoelectric members capable of expanding and contracting in the Y direction in response to an applied voltage are connected to the floating piece. Sliders are disposed at the ends of the piezoelectric members which slide on the base and movable plate, respectively, the sliders being provided with electrically operated attractors which serve to attract and fasten the sliders to the base and plate. By selective application of voltage signals to the piezoelectric members and the attractors, the plate can be made to move simultaneously in orthogonal directions with respect to the base under the guidance of the floating piece.

Two-directional piezoelectric driven fine adjusting device

Disclosed is a vacuum valve apparatus comprising a valve head, a motor for driving the valve head, means for checking the position of the valve adapted to issue a first signal upon detecting that the valve head is moved to be within a predetermined valve-closed range, means for checking electric current adapted to issue a second signal when the driving current for the motor is increased to a predetermined value, switching means adapted to cut the driving current supply to the motor upon detecting said second signal, and means for issueing a third signal for confirming the complete closure of the valve when both of the first and the second signals are simultaneously obtained.

Vacuum valve apparatus

A field emission electron gun according to this invention comprises a cathode for emitting electrons, an anode, a high voltage source which applies a high voltage between the cathode and the anode in order to cause emission of electrons from the cathode, a reference voltage source, voltage control means for controlling and stabilizing the output voltage of the high voltage source in response to an output voltage of the reference voltage source, means for detecting the value of an emission current from the cathode, means for delivering as an output a signal corresponding to the difference between the detected value and a desired value, and means for applying the output signal to the reference voltage source through a switch. The reference voltage source includes means which, when the switch is in the closed state, controls the output voltage of the reference voltage source in response to the difference output signal, and means which, when the switch is in the open state, continues to hold the output voltage value of the reference voltage source immediately before the opening of the switch as it is. The electron gun of this invention accordingly conducts when the switch is in the closed state, a constant current operation which makes constant the emission current from the cathode, and conducts when the switch is in the open state, a constant voltage operation which makes constant the voltage applied between the cathode and the anode.

Field emision electron gun with controlled power supply

In a sample analysis apparatus, a sample to be analyzed is irradiated by the electron beam from an electron gun, and the information obtained from the sample and characteristic of the sample is detected for the analysis of the sample. The electron gun and the sample are placed respectively in an electron gun chamber and in a sample chamber. An intermediate chamber is located between the electron gun chamber and the sample chamber. That portion of the sample chamber which contains the sample is protuberant into the intermediate chamber. The intermediate chamber is evacuated to a degree of vacuum higher than the sample chamber but lower than the electron gun chamber.

Sample analysis apparatus using electron beam irradiation

A field emission electron gun capable of generating a highly stabilized electron beam, comprises a cathode tip for emitting electrons, an anode for attracting and accelerating the electrons, and means for heating the anode. A surface layer of the anode, which is to be bombarded by the electrons, consists essentially of getter material such as Zr-Al alloy. The anode heating means serves for heating the surface layer, so as to remove the absorbed gas molecules and to elevate the gettering effect of the getter material, whereby the absorbed gas molecules in the anode are hardly released therefrom, even if the anode surface is bombarded by the electrons. Therefore, the number of ions impinging on the cathode tip is remarkably reduced, and a stable electron beam can be obtained from the cathode tip.

A variable d.c. source is connected to electrodes provided on the inner and outer surfaces of a hollow cylindrical body formed of piezoelectric ceramic through a switch to achieve dilations of the body by a variable applied voltage. Leg members are fixed at both ends of said body member. Sliding members are further fixed on the lower surfaces of said leg members and are slidable on a base plate. Between said leg members and said base plate, d.c. sources are connected through switches to electrostatically fix the structure. The structure can be moved finely and stepwise in a predetermined direction by operating said switches.

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Saitama, Japan

Yoshio Sakitani