Inspection system by charged particle beam and method of manufacturing devices using the system
View Patent ↗An inspection apparatus by an electron beam comprises: an electron-optical device 70 having an electron-optical system for irradiating the object with a primary electron beam from an electron beam source, and a detector for detecting the secondary electron image projected by the electron-optical system; a stage system 50 for holding and moving the object relative to the electron-optical system; a mini-environment chamber 20 for supplying a clean gas to the object to prevent dust from contacting to the object; a working chamber 31 for accommodating the stage device, the working chamber being controllable so as to have a vacuum atmosphere; at least two loading chambers 41, 42 disposed between the mini-environment chamber and the working chamber, adapted to be independently controllable so as to have a vacuum atmosphere; and a loader 60 for transferring the object to the stage system through the loading chambers.
1. An inspection apparatus comprising:
a beam source for irradiating primary charged particles against a sample to be inspected;
a retarding-field type objective lens for decelerating said primary charged particles as well as for accelerating secondary charged particles generated by said electron beam irradiated against said sample to be inspected;
a detector for detecting said secondary charged particles;
an E×B deflecting system for deflecting said secondary charged particles toward said detector by a field where an electric field and a magnetic field cross at right angles; and
an electrode for controlling the electric field intensity in a plane of said sample to be inspected, said plane being exposed to the irradiation of said primary charged particle, said electrode being arranged between said retarding-field type objective lens and said sample to be inspected and having a shape approximately symmetrical with respect to the optical axis of irradiation of said primary charged particles,
wherein said secondary charged particles are projected by a projecting method so as to form an image of said sample to be detected by said detector,
wherein said inspection apparatus includes a numerical aperture and a field aperture, said numerical aperture constructing a telecentric electronic optical system with said retarding-field type objective lens,
said electron beam apparatus further comprising means for measuring the amount of the electric charge of said electrode and applying voltage to the electrode to irradiate electrons corresponding to the measured amount of the electric charge to offset the electric charge on the electrode.
2. An electron beam apparatus in accordance with claim 1 , in which a voltage applied to said electrode is set to control said electric field intensity depending on the category of said sample to be inspected.
3. An electron beam apparatus in accordance with claim 1 , in which said sample to be inspected is a semiconductor wafer, and said voltage applied to said electrode in order to control said electric field intensity is controlled depending on whether or not said semiconductor device has a via.
4. A method for manufacturing a device using an electron beam apparatus defined by claim 1 , said method characterized in that a semiconductor wafer, which has been prepared as said sample to be inspected, is inspected for defects by using said inspecting apparatus in a manufacturing processes of the device or subsequent to the process.
5. A method for manufacturing a device using an electron beam apparatus defined by claim 2 , said method characterized in that a semiconductor wafer, which has been prepared as said sample to be inspected, is inspected for defects by using said inspecting apparatus in a manufacturing processes of the device or subsequent to the process.
6. A method for manufacturing a device using an electron beam apparatus defined by claim 3 , said method characterized in that a semiconductor wafer, which has been prepared as said sample to be inspected, is inspected for defects by using said inspecting apparatus in a manufacturing processes of the device or subsequent to the process.
7. An electron beam apparatus in accordance with claim 1 , in which said numerical aperture is provided at a focusing location of said retarding-field type objective lens.
8. An electron beam apparatus in accordance with claim 1 , in which said primary charged particles irradiate said sample with parallel beams.
9. An electron beam apparatus in accordance with claim 1 , in which said apparatus comprises a secondary optical system that includes said retarding-field type objective lens, said numerical aperture, said E×B deflecting system, a second lens, said field aperture, a third lens, and a fourth lens.
10. An electron beam apparatus in accordance with claim 1 , in which an intermediate image of said sample is formed from said secondary charged particles at said field aperture.
11. An electron beam apparatus in accordance with claim 1 , in which said detector comprises a scintilator and a MCP.