Abstract: A method of scanning a sample includes simultaneously forming a plurality of co-linear scans. Each scan is formed by a sweep of a spot by an acousto-optical device (AOD). The co-linear scans are separated by a predetermined spacing. A first plurality of swaths are formed by repeating the simultaneous forming of the plurality of co-linear scans in a direction perpendicular to the co-linear scans. The first plurality of swaths have an inter-swath spacing that is the same as the predetermined spacing. The predetermined spacing can be a scan length or an integral number of scan lengths. A second plurality of swaths can be formed adjacent to the first plurality of swaths. Forming the second plurality of swaths can be performed in an opposite direction to that of the first plurality of swaths or in a same direction. An inspection system can implement this method by including a diffractive optical element (DOE) path after a magnification changer.

Abstract: An inspection system with selectable apodization includes a selectably configurable apodization device disposed along an optical pathway of an optical system. The apodization device includes one or more apodization elements operatively coupled to one or more actuation stages. The one or more actuation stages are configured to selectably actuate the one or more apodization elements along one or more directions. The inspection system includes a control system communicatively coupled to the one or more actuation stages. The control system is configured to selectably control an actuation state of at the one or more apodization elements so as to apply a selected apodization profile formed with the one or more apodization elements.

Abstract: A method of scanning a sample includes simultaneously forming a plurality of co-linear scans. Each scan is formed by a sweep of a spot by an acousto-optical device (AOD). The co-linear scans are separated by a predetermined spacing. A first plurality of swaths are formed by repeating the simultaneous forming of the plurality of co-linear scans in a direction perpendicular to the co-linear scans. The first plurality of swaths have an inter-swath spacing that is the same as the predetermined spacing. The predetermined spacing can be a scan length or an integral number of scan lengths. A second plurality of swaths can be formed adjacent to the first plurality of swaths. Forming the second plurality of swaths can be performed in an opposite direction to that of the first plurality of swaths or in a same direction. An inspection system can implement this method by including a diffractive optical element (DOE) path after a magnification changer.

Abstract: A method of scanning a sample includes simultaneously forming a plurality of co-linear scans. Each scan is formed by a sweep of a spot by an acousto-optical device (AOD). The co-linear scans are separated by a predetermined spacing. A first plurality of swaths are formed by repeating the simultaneous forming of the plurality of co-linear scans in a direction perpendicular to the co-linear scans. The first plurality of swaths have an inter-swath spacing that is the same as the predetermined spacing. A second plurality of swaths can be formed adjacent to the first plurality of swaths. Forming the second plurality of swaths can be performed in an opposite direction to that of the first plurality of swaths or in a same direction. An inspection system can implement this method by including a diffractive optical element (DOE) path after a magnification changer.

Abstract: Various embodiments for detecting defects on a wafer are provided. Some embodiments include matching a template image, in which at least some pixels are associated with regions in the device having different characteristics, to output of an electron beam inspection system and applying defect detection parameters to pixels in the output based on the regions that the pixels in the output are located within to thereby detect defects on the wafer.

Abstract: An inspection system with selectable apodization includes a selectably configurable apodization device disposed along an optical pathway of an optical system. The apodization device includes one or more apodization elements operatively coupled to one or more actuation stages. The one or more actuation stages are configured to selectably actuate the one or more apodization elements along one or more directions. The inspection system includes a control system communicatively coupled to the one or more actuation stages. The control system is configured to selectably control an actuation state of at the one or more apodization elements so as to apply a selected apodization profile formed with the one or more apodization elements.

Abstract: An inspection system with selectable apodization includes an illumination source configured to illuminate a surface of a sample, a detector configured to detect at least a portion of light emanating from the surface of the sample, the illumination source and the detector being optically coupled via an optical pathway of an optical system, a selectably configurable apodization device disposed along the optical pathway, wherein the apodization device includes one or more apodization elements operatively coupled to one or more actuation stages configured to selectably actuate the one or more apodization elements along one or more directions, and a control system communicatively coupled to the one or more actuation and configured to selectably control apodization of illumination transmitted along the optical pathway by controlling an actuation state of the one or more apodization elements.

Abstract: In one embodiment, a first vacuum chamber of an electron beam column has an opening which is positioned along an optical axis so as to pass a primary electron beam that travels down the column. A source that emits electrons is positioned within the first vacuum chamber. A beam-limiting aperture is configured to pass a limited angular range of the emitted electrons. A magnetic immersion lens is positioned outside of the first vacuum chamber and is configured to immerse the electron source in a magnetic field so as to focus the emitted electrons into the primary electron beam. An objective lens is configured to focus the primary electron beam onto a beam spot on a substrate surface so as to produce scattered electrons from the beam spot. Controllable deflectors are configured to scan the beam spot over an area of the substrate surface. Other features and embodiments are also disclosed.

Abstract: One embodiment relates to an electron-beam apparatus for defect inspection and/or review of substrates or for measuring critical dimensions of features on substrates. The apparatus includes an electron gun and an electron column. The electron gun includes an electron source configured to generate electrons for an electron beam and an adjustable beam-limiting aperture which is configured to select and use one aperture size from a range of aperture sizes. Another embodiment relates to providing an electron beam in an apparatus. Advantageously, the disclosed apparatus and methods reduce spot blur while maintaining a high beam current so as to obtain both high sensitivity and high throughput.

Abstract: In one embodiment, a first vacuum chamber of an electron beam column has an opening which is positioned along an optical axis so as to pass a primary electron beam that travels down the column. A source that emits electrons is positioned within the first vacuum chamber. A beam-limiting aperture is configured to pass a limited angular range of the emitted electrons. A magnetic immersion lens is positioned outside of the first vacuum chamber and is configured to immerse the electron source in a magnetic field so as to focus the emitted electrons into the primary electron beam. An objective lens is configured to focus the primary electron beam onto a beam spot on a substrate surface so as to produce scattered electrons from the beam spot. Controllable deflectors are configured to scan the beam spot over an area of the substrate surface. Other features and embodiments are also disclosed.

Abstract: A multi-spot scanning technique using a spot array having a predetermined gap between spots can advantageously provide scalability to a large number of spots as well as the elimination of cross-talk between channels. The multi-spot scanning technique can select a number of spots for the spot array (1D or 2D), determine a separation between the spots to minimize crosstalk, and perform a scan on a wafer using the spot array and a full field of view (FOV). Performing the scan includes performing a plurality of scan line cycles, wherein each scan line cycle can fill in gaps left by previous scan line cycles. This “delay and fill” scan allows large spacing between spots, thereby eliminating cross-talk at the detector plane. In one embodiment, the scan is begun and ended outside a desired scan area on the wafer to ensure full scan coverage.

Abstract: A tool for investigating a substrate, where the tool has a tool head for investigating the substrate, a chuck for disposing an upper surface of the substrate in proximity to the tool head, and an air bearing disposed on the tool head adjacent the substrate. The air bearing has a pressure source and a vacuum source, where the vacuum source draws the substrate toward the air bearing and the pressure source prevents the substrate from physically contacting the air bearing. The pressure source and the vacuum source work in cooperation to dispose the upper surface of the substrate at a known distance from the tool head. By using the air bearing as part of the tool in this manner, registration of the substrate to the tool head is accomplished relative to the upper surface of the substrate, not the back side of the substrate.

Abstract: One embodiment relates to an electron-beam apparatus for defect inspection and/or review of substrates or for measuring critical dimensions of features on substrates. The apparatus includes an electron gun and an electron column. The electron gun includes an electron source configured to generate electrons for an electron beam and an adjustable beam-limiting aperture which is configured to select and use one aperture size from a range of aperture sizes. Another embodiment relates to providing an electron beam in an apparatus. Advantageously, the disclosed apparatus and methods reduce spot blur while maintaining a high beam current so as to obtain both high sensitivity and high throughput.

Abstract: A tool for investigating a substrate, where the tool has a tool head for investigating the substrate, a chuck for disposing an upper surface of the substrate in proximity to the tool head, and an air bearing disposed on the tool head adjacent the substrate. The air bearing has a pressure source and a vacuum source, where the vacuum source draws the substrate toward the air bearing and the pressure source prevents the substrate from physically contacting the air bearing. The pressure source and the vacuum source work in cooperation to dispose the upper surface of the substrate at a known distance from the tool head. By using the air bearing as part of the tool in this manner, registration of the substrate to the tool head is accomplished relative to the upper surface of the substrate, not the back side of the substrate.

Abstract: A multi-spot scanning technique using a spot array having a predetermined gap between spots can advantageously provide scalability to a large number of spots as well as the elimination of cross-talk between channels. The multi-spot scanning technique can select a number of spots for the spot array (1D or 2D), determine a separation between the spots to minimize crosstalk, and perform a scan on a wafer using the spot array and a full field of view (FOV). Performing the scan includes performing a plurality of scan line cycles, wherein each scan line cycle can fill in gaps left by previous scan line cycles. This “delay and fill” scan allows large spacing between spots, thereby eliminating cross-talk at the detector plane. In one embodiment, the scan is begun and ended outside a desired scan area on the wafer to ensure full scan coverage.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square. The PSF provides selective filtering in two directions. In other words, the PSF provides two dimensional filtering.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square. The PSF provides selective filtering in two directions. In other words, the PSF provides two dimensional filtering.

Abstract: Disclosed are mechanisms for selectively filtering spatial portions of light emanating from a sample under inspection within an optical system. In one embodiment, a programmable spatial filter (PSF) is constructed from materials that are compatible with light in a portion of the UV wavelength range. In a specific implementation, the PSF is constructed from a UV compatible material, such as a polymer stabilized liquid crystal material. In a further aspect, the PSF also includes a pair of plates that are formed from a UV grade glass. The PSF may also include a relatively thin first and second ITO layer that results in a sheet resistance between about 100 and about 300 &OHgr; per square.