Abstract: A direct-write electron beam lithography system employing a patterned beam-defining aperture to enable the generation of high current-density shaped beams without the need for multiple beam-shaping apertures, lenses and deflectors is disclosed. Beam blanking is accomplished without the need for an intermediate crossover between the electron source and the wafer being patterned by means of a double-deflection blanker, which also facilitates proximity effect correction. A simple type of “moving lens” is utilized to eliminate off-axis aberrations in the shaped beam. A method for designing the patterned beam-defining aperture is also disclosed.

Abstract: A direct-write electron beam lithography system employing a patterned beam-defining aperture to enable the generation of high current-density shaped beams without the need for multiple beam-shaping apertures, lenses and deflectors is disclosed. Beam blanking is accomplished without the need for an intermediate crossover between the electron source and the wafer being patterned by means of a double-deflection blanker, which also facilitates proximity effect correction. A simple type of “moving lens” is utilized to eliminate off-axis aberrations in the shaped beam. A method for designing the patterned beam-defining aperture is also disclosed.

Abstract: A current density distribution characteristic within a beam pattern on a target object can be improved by using a simple-structured electron optical system and a single patterned beam-defining aperture. With an aperture layout modified to be physically fabricable, a current density distribution within the beam pattern is obtained (S5). Then, a current density uniformity is determined by applying preset determination threshold values to the current density distribution within the beam pattern BP obtained as described above (S6), and if it is found not to fall within a tolerance range, tentative inner block portions are set in tentative electron ray passing areas (S7 and S8). Subsequently, by appropriately iterating steps S5 to S8 for the aperture layout modified or renewed by the tentative inner block portions as described above, the tentative electron ray passing areas and the tentative inner block portions, satisfying determination criteria, are decided (S8).

Abstract: A direct-write electron beam lithography system employing a patterned beam-defining aperture to enable the generation of high current-density shaped beams without the need for multiple beam-shaping apertures, lenses and deflectors is disclosed. Beam blanking is accomplished without the need for an intermediate crossover between the electron source and the wafer being patterned by means of a double-deflection blanker, which also facilitates proximity effect correction. A simple type of “moving lens” is utilized to eliminate off-axis aberrations in the shaped beam. A method for designing the patterned beam-defining aperture is also disclosed.

Abstract: A detector optics system for collecting secondary electrons (SEs) and/or backscattered electrons (BSEs) in a multiple charged particle beam test system is disclosed. Aspects of the detector optics system include: the ability to image and/or electrically test a number of locations simultaneously across the full width of a large substrate with high throughput and uniform collection efficiency while avoiding crosstalk between signals generated by neighboring beams. In one embodiment, a linear array of N electron beams causes SEs to be emitted from the substrate, which are then collected by one or more linear arrays of ?2N detectors. Each linear array is connected to a signal combiner circuit which dynamically determines which detectors are collecting SEs generated by each electron beam as it scans across the substrate surface and then combines the signals from these detectors to form N simultaneous output signals (one per charged particle beam) for each detector array.

Abstract: A charged particle optical system for testing, imaging or inspecting substrates comprises: a charged particle optical assembly configured to produce a line of charged particle beams equally spaced along a main scan axis, each beam being deflectable through a large angle along the main scan axis; and linear detector optics aligned along the main scan axis. The detector optics includes a linear secondary electron detector, a field free tube, voltage contrast plates and a linear backscattered electron detector. The large beam deflection is achieved using an electrostatic deflector for which the exit aperture is larger than the entrance aperture. One embodiment of the deflector includes: two parallel plates with chamfered inner surfaces disposed perpendicularly to the main scan axis; and a multiplicity of electrodes positioned peripherally in the gap between the plates, the electrodes being configured to maintain a uniform electric field transverse to the main scan axis.

Abstract: A detector optics system for an electron probe system is disclosed. Aspects of the detector optics system include: the ability to simultaneously detect two electron populations, secondary electrons (SEs) and backscattered electrons (BSEs), wherein both populations are emitted from a substrate due to the impact of the electron probe. The design of the detector optics utilizes a field-free tunnel and substrate electric-field control electrodes to enable separation of the SEs and BSEs into two detectors, allowing simultaneous acquisition of topographic and elemental composition data, with minimal impact on the electron probe. The secondary electron signal is a monotonically-varying function of the voltage on the substrate surface. The ratio of the SE signal to the BSE signal gives a testing signal which is independent of the primary beam current and serves as an absolute voltage probe of surface voltages without the need for an external reference voltage.

Abstract: A charged particle beam column for substrate inspection includes detector optics with high secondary electron detection efficiency combined with minimal distortion of the charged particle beam. One embodiment of the detector optics includes a symmetrizing electrode configured with a secondary electron detector to produce a generally cylindrically symmetric electric field about the optical axis of the column. Control electrodes may be used for screening the charged particle beam from the secondary electron detector and for controlling the electric field at the surface of the substrate. In some embodiments, the control electrodes are cylindrically symmetric about the optical axis; whereas in other embodiments, the cylindrical symmetry of one or more control electrodes is broken in order to improve the secondary electron detection efficiency.

Abstract: A multi-column electron beam inspection system is disclosed herein. The system is designed for electron beam inspection of semiconductor wafers with throughput high enough for in-line use. The system includes field emission electron sources, electrostatic electron optical columns, a wafer stage with six degrees of freedom of movement, and image storage and processing systems capable of handling multiple simultaneous image data streams. Each electron optical column is enhanced with an electron gun with redundant field emission sources, a voltage contrast plate to allow voltage contrast imaging of wafers, and an electron optical design for high efficiency secondary electron collection.

Abstract: A multi-column charged particle optics assembly comprises: a first optical component which is continuous through all columns of the charged particle optics assembly; and a multiplicity of independently alignable second optical components coupled to the first optical component, such that there is one second component for each column in the charged particles optics assembly. The first component provides mechanical integrity to the charged particle optics assembly and each second optical component is independently alignable to the optic axis of its corresponding column. In a further embodiment, the charged particle optics assembly comprises: first and second continuous optical components; and a multiplicity of independently alignable electrodes coupled to the second optical component, such that there is a corresponding independently alignable electrode for each column.

Abstract: A system for precisely positioning and moving a platform relative to a support structure is disclosed herein. The platform is particularly suitable for carrying wafers. Charged particle optics can be attached to the support structure. The platform positioning system comprises a stage, comprising a base, a platform and stage actuators, the stage actuators being coupled to the platform and the platform being coupled to the base; a frame attached to the base; a support structure mechanically coupled to the frame; stage sensors attached to the support structure, for sensing the position of the platform relative to the support structure; and a current control system coupled to the stage sensors and the stage actuators. The current control system may include a predictor for generating an ouptut signal anticipating the actual position of the platform relative to the support structure in real time.

Abstract: A multi-column electron beam inspection system is disclosed herein. The system is designed for electron beam inspection of semiconductor wafers with throughput high enough for in-line use. The system includes field emission electron sources, electrostatic electron optical columns, a wafer stage with six degrees of freedom of movement, and image storage and processing systems capable of handling multiple simultaneous image data streams. Each electron optical column is enhanced with an electron gun with redundant field emission sources, a voltage contrast plate to allow voltage contrast imaging of wafers, and an electron optical design for high efficiency secondary electron collection.

Abstract: A charge particle optical column capable of being used in a high throughput, mutli-column, multi-beam electron beam lithography system is disclosed herein. The column has the following properties: purely electrostatic components; small column footprint (20 mm square); multiple, individually focused charge particle beams; telecentric scanning of all beams simultaneously on a wafer for increased depth of field; and conjugate blanking of the charged particle beams for reduced beam blur. An electron gun is disclosed that uses microfabricated, field emission sources and a microfabricated aperture-deflector assembly. The aperture-deflector assembly acts as a perfect lens in focusing, steering and blanking a multipicity of electron beams through the back focal plane of an immersion lens located at the bottom of the column. Beam blanking can be performed using a gating signal to decrease beam blur during writing on the wafer.

Abstract: An image processing system for use in semiconductor wafer inspection comprises a multiplicity of self-contained image processors for independently performing image cross-correlation and defect detection. The system may also comprise an image normalization engine for performing image brightness and contrast normalization. The self-contained image processors and image normalization engine access image data from a memory array; the array is fed data from a multiplicity of imaging modules operating in parallel. The memory array is configured to allow simultaneous access for data input, normalization, and cross-correlation and defect detection. Multiple image processing systems can be configured in parallel as a single image processing computer, all sending defect data to a common display module.

Abstract: An electron optics assembly for a multi-column electron beam inspection tool comprises a single accelerator structure and a single focus electrode mounting plate for all columns; the other electron optical components are one per column and are independently alignable. The accelerator structure comprises first and final accelerator electrodes with a set of accelerator plates in between; the first and final accelerator plates have an aperture for each column and the accelerator plates have a single aperture such that the electron optical axes for all columns pass through the single aperture. Independently alignable focus electrodes are attached to the focus electrode mounting plate, allowing each electrode to be aligned to the electron optical axis of its corresponding column. There is one electron gun per column, mounted on the top of the single accelerator structure. In other embodiments, the electron guns are mounted to a single gun mounting plate positioned above the accelerator structure.

Abstract: A charge particle optical column capable of being used in a high throughput, mutli-column, multi-beam electron beam lithography system is disclosed herein. The column has the following properties: purely electrostatic components; small column footprint (20 mm square); multiple, individually focused charge particle beams; telecentric scanning of all beams simultaneously on a wafer for increased depth of field; and conjugate blanking of the charged particle beams for reduced beam blur. An electron gun is disclosed that uses microfabricated field emission sources and a microfabricated aperture-deflector assembly. The aperture-deflector assembly acts as a perfect lens in focusing, steering and blanking a multipicity of electron beams through the back focal plane of an immersion lens located at the bottom of the column. Beam blanking can be performed using a gating signal to decrease beam blur during writing on the wafer.

Abstract: A charge particle optical column capable of being used in a high throughput, mutli-column, multi-beam electron beam lithography system is disclosed herein. The column has the following properties: purely electrostatic components; small column footprint (20 mm square); multiple, individually focused charge particle beams; telecentric scanning of all beams simultaneously on a wafer for increased depth of field; and conjugate blanking of the charged particle beams for reduced beam blur. An electron gun is disclosed that uses microfabricated field emission sources and a microfabricated aperture-deflector assembly. The aperture-deflector assembly acts as a perfect lens in focusing, steering and blanking a multipicity of electron beams through the back focal plane of an immersion lens located at the bottom of the column. Beam blanking can be performed using a gating signal to decrease beam blur during writing on the wafer.

Abstract: A flexural joint, in particular a flexural thrust joint suitable for precision stages and application requiring vacuum is disclosed herein. A two degree of freedom joint comprises: two joint elements, each with a load bearing surface; two flexures attached between the elements, such that the flexures are under tension when the joint is subject to a compressive load. The flexures are long and thin, such that they can twist and bend, giving the joint two degrees of freedom. A three degree of freedom joint comprises: a first joint element with a load bearing surface; a second joint element with a second load bearing surface; a third joint element; two first flexures attached between the second and third elements; two second flexures attached between the third and first elements, such that both the first and second flexures are under tension when the joint is subject to a compressive load.

Abstract: An ultra-high precision stage incorporating a novel, legged design suitable for applications requiring high voltage and vacuum is disclosed herein. The stage comprises: a base; a frame attached to the base; a platform with a bottom platform surface; at least three adjustable limbs coupled to the base and the bottom platform surface, each limb comprising a raising member attached to the base, a first attachment member attached to the raising member, a leg, a bottom end of the leg attached to the first attachment member, a second attachment member attached to a top end of the leg and the second attachment member attached to the bottom platform surface; and platform movement members coupled to the platform and the frame, providing precise positioning and movement of the platform. The attachment members can be flexure joints; further, they can be flexural thrust joints. The platform can have six degrees of freedom of movement and accommodate wafers with diameters of 300 mm. The stage can weigh less than 100 lbs.