Environmental scanning electron microscope

An environmental scanning electron microscope comprising:

• (a) a vacuum column having a pressure limiting aperture at the lower end thereof;
• (b) a charged particle beam source located within the vacuum column which emits a charged particle beam;
• (c) focusing means located within the vacuum column which directs a charged particle beam emitted by the charged particle beam source through said pressure limiting aperture;
• (d) a specimen chamber, positioned below said pressure limiting aperture, which maintains the specimen enveloped in gas at a pressure of approximately 1 to 50 Torr in registration with the pressure limiting aperture such that a surface of the sample may be exposed to a charged particle beam emitted from the charged particle beam source and directed through said pressure limiting aperture;
• (e) a biased ring detector disposed between said specimen and said pressure limiting aperture to detect secondary electron signals emanating from the surface of the specimen;
• and
• (f) a biased pressure limiting aperture detector formed integrally with said pressure limiting aperture to reduce signals emanating from backscattered electrons and to reduce noise generated by said electron beam.

A scanning electron microscope comprising:

• (a) means for generating and directing an electron beam towards a specimen;
• (b) a specimen chamber which maintains the specimen enveloped in a gaseous environment;
• (c) means for detecting secondary electron signals emanating from the surface of the specimen;
• and
• (d) means for reducing signals emanating from backscattered electrons and means for reducing signal noise generated by said electron beam.

An environmental scanning electron microscope comprising:

• (a) means for generating and directing an electron beam toward a specimen;
• (b) means for detecting secondary electron signals emanating from the surface of the specimen which is in the form of a thin biased ring electrode;
• (c) means for reducing signals emanating from backscattered electrons and means for reducing signal noise generated by said electron beam;
• and
• (d) means for amplifying signals collected by said ring electrode including an amplifier receiving signals collected at said ring electrode, said amplifier floating at the bias voltage of said ring electrode, and the output of said amplifier being supplied to display means.

An environmental scanning electron microscope which permits a substantial portion of a specimen to be examined by an operator comprising:

• (a) a vacuum column having a pressure limiting aperture at the lower end thereof;
• (b) means for generating and directing an electron beam through said pressure limiting aperture toward a specimen;
• (c) a specimen chamber, positioned below said pressure limiting aperture, which maintains the specimen enveloped in gas in registration with the pressure limiting aperture;
• (d) a magnetic focusing lens separating said vacuum column and said specimen chamber and defining said pressure limiting aperture;
• and
• (e) an optical window system including optical image production means for illuminating said specimen from a light source and for reflecting said image of said specimen to video means to provide a continuous optical view of the specimen.

A scanning electron microscope which allows an optical view of the specimen comprising:

• (a) a vacuum column having a pressure limiting aperture at the lower end thereof;
• (b) means for generating and directing an electron beam through said pressure limiting aperture toward a specimen;
• (c) a specimen chamber, positioned below said pressure limiting aperture, which maintains the specimen enveloped in gas in registration with the pressure limiting aperture;
• (d) a magnetic focusing lens separating said vacuum column and said specimen chamber and defining said pressure limiting aperture;
• and
• (e) an optical window system including optical image production means for illuminating said specimen from a light source and for reflecting said image of said specimen to video means to provide a continuous optical view of the specimen.

An environmental scanning electron microscope comprising:

• (a) means for generating and directing an electron beam toward a specimen;
• (b) means for detecting secondary electron signals emanating from the surface of the specimen to provide electron images of the specimen;
• (c) an optical window system including optical image production means for producing optical images of said specimen;
• and
• (d) display means including a screen having an image display area and a menu display area for displaying operational and status information for an operator, and wherein either of said electron images or said optical images may be displayed in said image display area.

A scanning electron microscope comprising:

• (a) means for generating and directing an electron beam toward a specimen;
• (b) means for detecting secondary electron signals emanating from the surface of the specimen to provide electron images of the specimen;
• (c) an optical window system including optical image production means for producing optical images of said specimen;
• and
• (d) display means including a screen having an image display area and a menu display area for displaying operational and status information for an operator, and wherein either of said electron images or said optical images may be displayed in said image display area.

An environmental scanning electron microscope comprising:

• (a) means for generating and directing an electron beam towards a specimen;
• (b) a vacuum column having a pressure limiting aperture assembly at the lower end thereof;
• (c) a specimen chamber in which said specimen is mounted such that a surface of said specimen may be exposed to said electron beam;
• and
• (d) an X-ray detector mounted in said specimen chamber to generate X-ray information from X-ray signals emanating from the surface of said specimen, said X-ray detector having a take-off angle of approximately 30.degree..