A precision stage for an electron beam exposure apparatus

Abstract

The application discloses a precision workpiece table for an electron beam exposure device, comprising a motion table on the upper layer and a slide glass table on the lower layer; the motion table comprises a mounting bottom plate, a Y-direction motion mechanism and an X-direction motion mechanism arranged in sequence from bottom to top; the slide glass table comprises a connecting bottom plate, an intermediate plate, a top plate and an integrated mirror arranged in sequence from bottom to top; the integrated mirror is used for supporting a mask plate; the connecting bottom plate is fixedly connected with the X-direction motion mechanism; and a Z-direction adjusting mechanism is arranged between the top plate and the connecting bottom plate, so as to realize position adjustment of the workpiece table in the X-direction, the Y-direction and the Z-direction. The application has the characteristics of compact structure, convenient operation, high reliability and the like, realizes precise adjustment of the working position of the mask plate, and thus ensures that the mask plate is always at the same height in the exposure process, and high-precision electron beam exposure is completed.

Description

Technical Field

[0001] This invention relates to the field of electron beam exposure equipment technology, and more specifically to a precision workpiece stage for electron beam exposure equipment. Background Technology

[0002] Electron beam lithography (EBRT) is a crucial piece of equipment that uses electron beam generation, acceleration, focusing, and deflection to precisely expose materials for fabricating micro- and nano-sized patterned structures. In the field of micro- and nano-fabrication technology, EBRT is a vital process and one of the core technologies for achieving high-precision pattern fabrication of photomasks.

[0003] Because the exposure accuracy requirements for the photomask pattern are extremely high, and the main and subfield regions of the electron optical column during the exposure process are both at the micrometer level, the motion accuracy requirements for the workpiece stage are also extremely high. Simultaneously, since the adjustable range of the electron beam's focusing height in the vertical direction (Z) during photomask exposure is also at the micrometer level, the vertical deviation of the workpiece stage supporting the photomask cannot be significant, and the height error of the photomask support point must be controlled within 3 micrometers to accommodate electron beam height adjustments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a precision workpiece stage for electron beam exposure equipment that is compact in structure, easy to operate, adaptable to the environment, and has high control accuracy, in order to overcome the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A precision workpiece stage for an electron beam exposure apparatus includes an upper motion stage and a lower substrate stage. The motion table includes a mounting base plate, a Y-axis motion mechanism, and an X-axis motion mechanism arranged sequentially from bottom to top; The stage includes a connecting base plate, a middle plate, a top plate, and an integrated mirror arranged sequentially from bottom to top. The integrated mirror is used to support the mask. The connecting base plate is connected and fixed to the X-axis motion mechanism. A Z-axis adjustment mechanism is provided between the top plate and the connecting base plate to realize the position adjustment of the mask in the X, Y, and Z axes.

[0006] As a further improvement of the present invention, the Y-axis motion mechanism includes a Y-axis motion plate and a Y-axis guide rail assembly. The Y-axis motion plate is connected to the mounting base plate through the Y-axis guide rail assembly, and a Y-axis drive connection assembly is provided on one side of the Y-axis motion plate to connect to an external drive source.

[0007] As a further improvement of the present invention, the X-axis motion mechanism includes an X-axis motion plate and an X-axis guide rail assembly. The X-axis motion plate and the Y-axis motion plate are connected by the X-axis guide rail assembly, and an X-axis drive connection assembly is provided on one side of the X-axis motion plate.

[0008] As a further improvement of the present invention, both the side of the mounting base plate and the side of the Y-axis motion plate are provided with limiting blocks. The limiting blocks on the side of the mounting base plate are used to limit the displacement of the Y-axis motion plate, and the limiting blocks on the side of the Y-axis motion plate are used to limit the displacement of the X-axis motion plate.

[0009] As a further improvement of the present invention, the Z-axis adjustment mechanism includes an elastic thin plate, a Z-axis support, a wedge block, and a bearing seat assembly; the Z-axis support is disposed on the connecting base plate, and the Z-axis support is connected to the top plate through the elastic thin plate; the bearing seat assembly is disposed through the top plate, and the top surface of the bearing seat assembly is connected to the integrated mirror, the bearing of the bearing seat assembly rests on the inclined surface at the top of the wedge block, and the flat surface at the bottom of the wedge block is connected to the intermediate plate; The connecting base plate and the intermediate plate are connected by a guide rail assembly. The connecting base plate is equipped with a piezoelectric ceramic motor, and the output end of the piezoelectric ceramic motor is connected to the side of the intermediate plate. When the piezoelectric ceramic motor drives the intermediate plate to move in the X direction, the wedge block moves horizontally in the X direction, and the bearing of the bearing seat assembly slides along the inclined surface of the wedge block, realizing the small displacement movement of the stage in the Z direction.

[0010] As a further improvement of the present invention, the connecting base plate is also provided with a grating assembly, which is located on the side of the intermediate plate to detect the displacement of the intermediate plate along the X direction in real time.

[0011] As a further improvement of the present invention, the X-guide rail assembly, the Y-guide rail assembly and the rail assembly all adopt cross roller guide rail assemblies.

[0012] As a further improvement of the present invention, the integrated mirror is provided with a plurality of support columns of equal height to support the mask plate.

[0013] As a further improvement of the present invention, the integrated mirror is also provided with a Faraday cup and a plurality of positioning marker blocks. The Faraday cup is used to measure the magnitude of the electron beam current, and the height difference between two adjacent positioning marker blocks is 50±1μm.

[0014] As a further improvement of the present invention, the side of the integrated mirror is provided with reflective surfaces along the X and Y directions to cooperate with the laser interference system to monitor and provide feedback on the position of the workpiece stage in real time.

[0015] Compared with the prior art, the advantages of the present invention are as follows: This invention relates to a precision stage for electron beam exposure equipment. By employing a layered, decoupled motion stage and wafer stage architecture, combined with a cross-roller guide and a piezoelectric ceramic-driven wedge-shaped Z-axis adjustment mechanism, it achieves active, continuous, and nanometer-level compensation of the mask height through the mechanical conversion principle of horizontal micro-displacement to vertical displacement. Simultaneously, the entire structure utilizes non-magnetic materials and integrates a laser interference reflective surface and multi-level height markings, eliminating magnetic field interference to the electron beam and constructing a multi-dimensional closed-loop feedback system. This invention, through the synergistic effect of mechanical structure, driving method, and sensor integration, fundamentally solves the technical bottleneck of traditional stages in electron beam exposure where height drift and magnetic interference coexist, significantly improving the resolution, overlay accuracy, and process stability of the exposed pattern. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the structural principle of a precision workpiece stage used in an electron beam exposure device according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram of the structural principle of the motion table in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the slide carrier platform in a specific embodiment of the present invention.

[0017] Legend: 100, Motion stage; 200, Slide stage; 300, Mask plate; 101, X-axis motion plate; 102, Y-axis motion plate; 103, X-axis guide rail assembly; 104, Y-axis guide rail assembly; 105, Mounting base plate; 106, X-axis drive connection assembly; 107, Y-axis drive connection assembly; 108, Limiting block; 201, Integrated mirror; 202, Reflective surface; 203, Support column; 204, Faraday cup; 205, Positioning mark block; 206, Elastic sheet; 207, Z-axis support column; 208, Wedge block; 209, Guide rail assembly; 210, Bearing seat assembly; 211, Piezoelectric ceramic motor; 212, Grating assembly; 213, Connecting base plate; 214, Intermediate plate; 215, Top plate. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0021] Example like Figure 1 , Figure 2 and Figure 3 As shown, the precision workpiece stage for an electron beam exposure apparatus of the present invention includes an upper motion stage 100 and a lower substrate stage 200. The layered architecture separates the horizontal large-stroke scanning motion from the vertical precision bearing and fine-tuning functions in physical space. This structurally avoids the direct transmission of coupling errors caused by motion inertia or thermal deformation to the mask support surface, as is common in traditional integrated designs, thus laying a stable mechanical foundation for achieving nanometer-level exposure accuracy.

[0022] like Figure 2 As shown, the motion table 100 includes a mounting base plate 105, a Y-axis motion mechanism, and an X-axis motion mechanism arranged sequentially from bottom to top. Specifically, the mounting base plate 105 serves as the static reference platform for the entire workpiece table and is typically fixed to the equipment base, providing a highly rigid support interface for the upper motion components. The Y-axis motion mechanism and the X-axis motion mechanism are arranged in an orthogonal stack above the mounting base plate 105, respectively responsible for realizing the macroscopic displacement of the workpiece table in two degrees of freedom in the horizontal plane. It should be understood that although this embodiment shows a stacking order with the Y-axis mechanism at the bottom and the X-axis mechanism at the top, in other embodiments, as long as the function of independent driving and guiding in both X and Y directions can be achieved, their hierarchical order or layout can be flexibly adjusted according to the overall machine space constraints.

[0023] like Figure 3As shown, the stage 200 includes a connecting base plate 213, a middle plate 214, a top plate 215, and an integrated mirror 201 arranged sequentially from bottom to top. The integrated mirror 201 supports the mask 300. The connecting base plate 213 is connected and fixed to the X-axis motion mechanism. A Z-axis adjustment mechanism is provided between the top plate 215 and the connecting base plate 213 to realize the position adjustment of the mask 300 in the X, Y, and Z axes. Specifically, the stage 200 is rigidly connected to the top output end of the motion stage 100 through the connecting base plate 213, thereby performing horizontal scanning synchronously with the motion stage 100. The middle plate 214 and the top plate 215 constitute the execution carrier of the Z-axis adjustment mechanism, while the integrated mirror 201 is located at the top and directly supports the mask 300. The Z-axis adjustment mechanism is set in the internal space between the top plate 215 and the connecting base plate 213, and its function is to independently and actively compensate for the height attitude of the mask 300 without interfering with the horizontal motion.

[0024] To meet the stringent requirements of the magnetic field environment in electron beam exposure processes, in this embodiment, all structural components of the stage 100 and the stage 200 are made of non-magnetic or weakly magnetic materials. For example, the mounting base 105, the Y-axis motion plate 102, the X-axis motion plate 101, and the various layers of the stage 200 can be made of high-purity alumina ceramic, microcrystalline glass, or aerospace-grade aluminum alloy that has undergone demagnetization treatment. This fundamentally eliminates the Lorentz force interference of the residual magnetic field of the workpiece stage itself on the electron beam trajectory, preventing image distortion and resolution degradation, and ensuring the purity and imaging quality of the electron optical path system.

[0025] like Figure 2 As shown, in this embodiment, the Y-axis motion mechanism includes a Y-axis motion plate 102 and a Y-axis guide rail assembly 104. The Y-axis motion plate 102 is connected to the mounting base plate 105 via the Y-axis guide rail assembly 104, and a Y-axis drive connection assembly 107 is provided on one side of the Y-axis motion plate 102 to connect to an external drive source. Specifically, the Y-axis motion plate 102 serves as a movable base supporting the upper X-axis mechanism and is constrained to the mounting base plate 105 via the Y-axis guide rail assembly 104, retaining only a single translational degree of freedom along the Y-axis. The Y-axis drive connection assembly 107 is typically designed as a reserved mounting position for a flexible coupling interface or a precision lead screw nut seat. Its function is to transmit the power of an external linear motor or rotary motor to the Y-axis motion plate 102 without loss, while isolating the motor vibration from interfering with the motion table body. Through the independent guide and drive interface design, the Y-axis motion is ensured to have extremely high straightness and repeatability, providing a dynamically stable reference plane for the upper X-axis motion and effectively avoiding the amplification of Abbe error caused by Y-axis motion attitude deviation.

[0026] Based on this, the X-axis motion mechanism includes an X-axis motion plate 101 and an X-axis guide rail assembly 103. The X-axis motion plate 101 and the Y-axis motion plate 102 are connected by the X-axis guide rail assembly 103, and an X-axis drive connection assembly 106 is provided on one side of the X-axis motion plate 101. Specifically, the X-axis motion plate 101 is orthogonally stacked on the Y-axis motion plate 102 through the X-axis guide rail assembly 103, forming a classic XY two-dimensional serial motion platform. The X-axis drive connection assembly 106 and the Y-axis drive connection assembly 107 are spatially arranged to avoid each other and prevent motion interference. It should be understood that although this embodiment shows a stacked form with Y below and X above, in other embodiments, if it is necessary to lower the center of gravity or adapt to specific optical path requirements, an inverted layout with X below and Y above can also be adopted, or an XY parallel decoupling structure can be adopted. As long as the orthogonal independent motion of the two axes can be achieved, it falls within the protection scope of this invention.

[0027] The orthogonal arrangement accuracy of the X-axis guide rail assembly 103 and the Y-axis guide rail assembly 104 directly determines the perpendicularity of the workpiece stage coordinate system. In this embodiment, through precision machining and assembly processes, the perpendicularity of the two-axis motion is controlled within 2μm, thereby meeting the stringent requirements of electron beam exposure for the planar rectangular coordinate system.

[0028] like Figure 2 As shown, both the side of the mounting base plate 105 and the side of the Y-axis motion plate 102 are provided with limiting blocks 108. The limiting block 108 on the side of the mounting base plate 105 is used to limit the displacement of the Y-axis motion plate 102, and the limiting block 108 on the side of the Y-axis motion plate 102 is used to limit the displacement of the X-axis motion plate 101. Specifically, the limiting blocks 108, as physical hard limiting devices, are respectively set outside the extreme positions at the end of each stroke. When the control system fails or the drive malfunctions, causing the moving parts to exceed the preset safe stroke range, the limiting blocks 108 can forcibly stop the motion plates from continuing to move, preventing the guide rail slider from dislodging, the cable from breaking, or adjacent parts from catastrophic collisions.

[0029] In this embodiment, the X-axis guide rail assembly 103, the Y-axis guide rail assembly 104, and the guide rail assembly 209 all employ crossed roller guide rail assemblies. Specifically, the crossed roller guide rail achieves line contact between the rolling elements and the track surface by alternately arranging cylindrical rollers within V-grooves. Compared to the point contact of traditional ball bearing guide rails, its contact area is significantly increased, resulting in a higher rigidity coefficient and anti-overturning moment capability. In the precision workpiece stage of an electron beam exposure equipment, this high rigidity characteristic effectively suppresses pitch, yaw, and roll errors caused by acceleration and deceleration inertial forces during movement, ensuring the attitude stability of the mask during high-speed scanning. Simultaneously, the crossed roller guide rail has an extremely low coefficient of friction and a small difference between dynamic and static friction, eliminating low-speed crawling and enabling nanoscale micro-feeding.

[0030] It should be noted that although the preferred cross roller guide is preferred in this embodiment, it can also be replaced with preloaded linear ball guide, hydrostatic air bearing guide or magnetic levitation guide in application scenarios with different load or accuracy requirements, as long as it can achieve the functions of low friction and high guiding accuracy.

[0031] like Figure 3 As shown, in this embodiment, the Z-axis adjustment mechanism includes an elastic thin plate 206, a Z-axis support column 207, a wedge block 208, and a bearing seat assembly 210. Specifically, the Z-axis support column 207 is mounted on the connecting base plate 213, and the Z-axis support column 207 is connected to the top plate 215 via the elastic thin plate 206, thus constructing a flexible guiding constraint system. The Z-axis support column 207 acts as a rigid support column, determining the reference height position of the top plate 215 relative to the connecting base plate 213. The elastic thin plate 206 utilizes the material's own elastic deformation capability to allow the top plate 215 to generate micron-level controlled displacement in the Z-axis, while providing extremely high lateral stiffness in the X and Y axes to resist shear forces.

[0032] Furthermore, the bearing housing assembly 210 is disposed through the top plate 215, and the top surface of the bearing housing assembly 210 is connected to the integrated mirror 201. The bearing of the bearing housing assembly 210 rests on the inclined surface of the top of the wedge block 208, and the flat surface of the bottom of the wedge block 208 is connected to the intermediate plate 214. Specifically, the wedge block 208, as a precision-machined inclined surface transmission component, has its top inclined surface angle rigorously calculated and ground, typically set between 5° and 15°, to ensure sufficient lift while achieving a high displacement amplification ratio and self-locking stability. The bearing in the bearing housing assembly 210 is preferably a high-precision miniature ball bearing or cylindrical roller bearing, and its contact with the inclined surface of the wedge block 208 is rolling friction. This not only significantly reduces motion resistance, but more importantly, eliminates the difference between static and dynamic friction coefficients common in sliding friction, thereby avoiding the crawling phenomenon during low-speed micro-movements. When height adjustment is required, external force drives the wedge block 208 to move horizontally, forcing the bearing to climb or descend along the inclined plane, thereby driving the top plate 215 and the integrated mirror 201 to rise and fall synchronously. Since the entire process involves only a transformation of pure mechanical geometry, there is no thread backlash or gear backlash, so the transmission chain has a natural zero-backlash error characteristic, ensuring bidirectional repeatability positioning accuracy for Z-axis adjustment.

[0033] At the drive level, the connecting base plate 213 and the intermediate plate 214 are connected via a guide rail assembly 209. A piezoelectric ceramic motor 211 is mounted on the connecting base plate 213, and the output end of the piezoelectric ceramic motor 211 is connected to the side of the intermediate plate 214. When the piezoelectric ceramic motor 211 drives the intermediate plate 214 to move along the X direction, the wedge block 208 moves horizontally along the X direction, and the bearing of the bearing seat assembly 210 slides along the inclined surface of the wedge block 208, realizing a small displacement movement of the stage 200 along the Z direction. Specifically, the piezoelectric ceramic motor 211 utilizes the inverse piezoelectric effect to generate nanometer-level stepping linear motion, directly driving the intermediate plate 214 to perform high-precision X-axis translation under the constraint of the guide rail assembly 209. Due to the displacement amplification effect of the wedge mechanism, the horizontal micro-displacement of the piezoelectric ceramic motor 211 is proportionally reduced and converted into the vertical micro-displacement of the top plate 215. For example, when the wedge angle is 10°, the horizontal displacement is about 5.7 times the vertical displacement. This means that if the piezoelectric motor resolution is 1nm, the theoretical Z-axis resolution can reach the order of 0.17nm. By using the strategy of "large stroke horizontal drive + small stroke vertical output", the space constraints and heat dissipation difficulties faced by directly arranging the driver in the Z-axis are cleverly avoided.

[0034] In this embodiment, to construct a complete closed-loop control system, a grating assembly 212 is also provided on the connecting base plate 213. The grating assembly 212 is located on the side of the intermediate plate 214 to detect the displacement of the intermediate plate 214 along the X direction in real time. Specifically, the grating assembly 212 includes a grating ruler and a reading head, directly measuring the actual horizontal position of the intermediate plate 214 relative to the connecting base plate 213, rather than relying on the internal estimation value of the piezoelectric ceramic motor 211. Through the high-frequency real-time displacement signal obtained by the grating assembly 212, the control system, combined with the preset wedge angle parameters, can accurately calculate the actual Z-direction height of the current top plate 215, and compare the calculated value with the target height to form a high-frequency closed-loop feedback loop. This indirect measurement method based on a geometric model, compared with directly installing sensors in the Z-direction, not only saves valuable vertical space, but also avoids the impact of sensor heat generation on the thermal stability of the mask, while effectively compensating for the slight changes in the wedge size caused by temperature changes, significantly improving the long-term accuracy and reliability of Z-direction adjustment.

[0035] In this embodiment, the guide rail assembly 209 also adopts a crossed roller guide rail assembly. In the Z-axis adjustment subsystem, the guide rail assembly 209 bears the weight of the intermediate plate 214 and all its moving parts, and withstands the lateral force generated by the wedge drive. The high rigidity and anti-overturning capability of the crossed roller guide rail are particularly critical here. It can ensure that the intermediate plate 214 maintains extremely high linear motion accuracy when subjected to dynamic loads, prevent changes in the wedge contact state due to guide rail deformation, and thus ensure the constant Z-axis displacement conversion coefficient.

[0036] In this embodiment, a Z-axis precision adjustment subsystem with high resolution, high rigidity, and high thermal stability is constructed through a four-fold synergistic mechanism of flexible guidance by elastic thin plate, backlash-free transmission by wedge-bearing, piezoelectric ceramic nano-drive, and closed-loop feedback of grating, which fundamentally solves the technical problem of mask height drift during electron beam exposure.

[0037] like Figure 3 As shown, in this embodiment, the integrated mirror 201 has multiple support pillars 203 of equal height evenly distributed on it to support the mask 300. Specifically, the support pillars 203 serve as the only mechanical interface between the mask 300 and the integrated mirror 201, and the coplanarity of their top planes directly determines the orientation reference of the mask 300 during the exposure process. In this embodiment, the multiple support pillars 203 are arranged in a three-point even distribution, and the height consistency of each support pillar 203 is achieved through precision grinding or selection to ensure that the height deviation of the upper surface of the mask 300 relative to the ideal focal plane is controlled within 3μm after installation. Compared with the traditional whole-surface adsorption or random support method, this evenly distributed design can effectively avoid pattern distortion caused by mask warping or internal stress release due to uneven local support force. Meanwhile, since the support column 203 and the integrated mirror 201 are made of the same material and are processed as a whole or bonded and cured with non-magnetic adhesive, the risk of gas release in the vacuum environment and the long-term drift caused by the mismatch of thermal expansion coefficients of the heterogeneous connectors are eliminated, providing an extremely stable static support interface for nanoscale exposure.

[0038] It should be understood that although cylindrical ceramic support columns are preferred in this embodiment, spherical contacts, conical bosses, or composite support structures with flexible buffer layers can also be used in other embodiments, as long as they can ensure multi-point equal-height support and meet the requirements of non-magnetic cleanliness.

[0039] Furthermore, the integrated mirror 201 is also equipped with a Faraday cup 204 and multiple positioning marker blocks 205. The Faraday cup 204 is used to measure the electron beam current magnitude, and the height difference between two adjacent positioning marker blocks 205 is 50±1μm. Specifically, the Faraday cup 204 is usually located in the non-exposure area at the edge of the integrated mirror 201. It has a deep-hole absorption cavity and a current lead-out terminal inside, which can quickly capture the electron beam and accurately measure the beam current intensity during the exposure gap. This provides direct feedback for real-time closed-loop control of the exposure dose and prevents linewidth deviation caused by beam current fluctuations.

[0040] More importantly, the multiple positioning marker blocks 205 are not on the same plane, but are designed as a stepped array with precisely known height differences. For example, in this embodiment, five positioning marker blocks 205 are set, and the height difference between adjacent blocks is strictly controlled within 50±1μm. This specific size design constitutes the absolute physical reference for Z-axis leveling: during system initialization or periodic calibration, the electron beam sequentially scans the positioning marker blocks 205 at different heights. By collecting the focus sharpness changes of secondary electron signals or backscattered electron signals, the optimal focus current-height correspondence curve can be fitted, and then the actual Z-axis zero point position of the current workpiece stage can be deduced. This self-calibration mechanism based on multi-level height marking completely eliminates the dependence on the zero-position stability of external Z-axis sensors. Even if the Z-axis adjustment mechanism experiences slight creep or temperature drift, the system can still automatically correct the error by rescanning the marker blocks, significantly improving the process robustness of long-term continuous exposure.

[0041] It should be noted that 50μm is only a preferred step size. In practical applications, the height difference can also be adjusted to 10μm, 100μm or other values ​​according to the electron beam depth of field range and the sensitivity of the leveling algorithm. As long as there is a distinguishable height difference between adjacent marker blocks and the difference value has been accurately calibrated by the system, the same Z-axis reference reconstruction function can be achieved.

[0042] like Figure 3 As shown, in this embodiment, the integrated mirror 201 has reflective surfaces 202 along both the X and Y directions on its side to cooperate with the laser interferometer system for real-time monitoring and feedback of the workpiece stage position. Specifically, the reflective surface 202 serves as the measurement target mirror of the laser interferometer, and its relative positional relationship with the integrated mirror 201 directly determines the error magnitude of the position feedback loop. In this embodiment, the X and Y reflective surfaces 202 are directly formed on the sidewall of the integrated mirror 201 through ultra-precision polishing or high-reflectivity coating. The perpendicularity between them is better than 2μm, and their parallelism with the corresponding motion axis is also better than 2μm. Compared with the traditional external independent reflector solution, this in-situ integrated design completely eliminates the creep effect of the adhesive layer during long-term vacuum service and the problem of inconsistent thermal deformation caused by temperature gradient, ensuring that the reflective surface 202 always maintains a rigid geometric locking relationship with the mask 300. When the laser beam emitted by the external laser interferometer illuminates the reflecting surface 202, the measured displacement is the true spatial coordinate of the mask 300, rather than the reading of a separate sensor. Combined with the feedback from the grating assembly 212, the system constructs a multi-dimensional fusion sensing system that includes horizontal position (laser interferometry), vertical drive displacement (grating), and absolute height reference (positioning marker block). This enables the workpiece stage to achieve full-degree-of-freedom state observation and control during high-speed scanning and precision leveling, fundamentally ensuring the overlay accuracy and resolution of electron beam direct-write patterns.

[0043] Before the electron beam exposure process begins, the mask loading and static reference establishment steps are performed first. Specifically, the mask 300 is placed on multiple height-equal support pillars 203 above the integrated mirror 201. Because the coplanarity of the top planes of the support pillars 203 is precisely ground and controlled within 3μm, and the flatness of the planes where each support point is located is better than 2μm, it is ensured that the mask 300 will not warp or experience localized stress concentration under its own weight, and the initial height deviation of its upper surface relative to the ideal focal plane is strictly limited to the sub-micron level. This high-precision establishment of the static reference is a prerequisite for achieving uniform focusing during subsequent dynamic exposure. If there are excessive undulations in the support surface, even if the Z-axis adjustment mechanism has compensation capabilities, unpredictable high-frequency errors may be introduced due to the elastic deformation of the mask itself, thus affecting the consistency of the pattern linewidth.

[0044] Following this, system initialization and multi-dimensional coordinate system calibration are performed. During this stage, the laser beam emitted by the external laser interferometer illuminates the X- and Y-axis reflecting surfaces 202 on the side of the integrated mirror 201, establishing a real-time position feedback loop for the workpiece stage. Since the perpendicularity between the reflecting surfaces 202 is better than 2μm, and their parallelism with their corresponding motion axes is also better than 2μm, errors caused by target mirror attitude deviations are fundamentally eliminated, ensuring that the displacement measured by the laser interferometer accurately reflects the spatial coordinates of the mask 300. Simultaneously, the system utilizes multiple positioning marker blocks 205 integrated on the integrated mirror 201 to perform Z-axis zero-point calibration. The electron beam sequentially scans adjacent positioning marker blocks 205 with a height difference of 50±1μm. By acquiring the focusing sharpness changes of the secondary electron signals, the system fits the corresponding curve of the optimal focusing current and height, thereby determining the absolute Z-axis reference of the current workpiece stage.

[0045] After entering the dynamic exposure stage, the workpiece stage needs to maintain the high stability of the mask 300 during high-speed scanning. Specifically, when the motion stage 100 drives the stage 200 to perform X / Y scanning, fluctuations in ambient temperature, heat generated by mechanical friction, or microscopic unevenness of the guide rail may cause slight drift in the height of the mask. At this time, the piezoelectric ceramic motor 211 drives the wedge block 208 to generate corresponding horizontal micro-motion based on the horizontal displacement signal of the intermediate plate 214 fed back in real time by the grating assembly 212. This is converted into Z-axis compensation displacement of the top plate 215 and the integrated mirror 201 via the inclined plane transmission. Since this transmission chain has the characteristics of no backlash and no hysteresis error, and the grating assembly 212 directly measures the displacement of the drive end and converts it into vertical displacement by combining the wedge angle, a high-resolution closed-loop control loop is formed, which makes the Z-axis adjustment response speed reach the millisecond level and the steady-state positioning accuracy better than 1nm. By using the active real-time compensation mechanism, it is ensured that the mask is always within the optimal depth of focus range of the electron beam throughout the entire exposure field, which significantly improves the resolution and edge roughness performance of the pattern.

[0046] The achievement of the aforementioned process effects highly depends on the precision assembly and material selection of each component of the workpiece stage. For example, the flatness of the mounting surfaces of the X-axis guide rail assembly 103 and the Y-axis guide rail assembly 104 in the motion stage 100 is less than 2μm, the coplanarity error of the mounting surfaces of the same pair of guide rails is less than 2μm, and the parallelism between the guide rail positioning surface and the direction of motion is less than 2μm. These stringent geometric tolerances ensure the straightness and perpendicularity (perpendicularity less than 2μm) of the X and Y axis movements, avoiding trajectory distortion during the scanning process. At the same time, the three-point support height error between each layer of the slide stage 200 is less than 3μm, ensuring that the Z-axis adjustment mechanism can maintain a constant displacement conversion coefficient when subjected to load. More importantly, all structural components of the entire workpiece stage, from the mounting base plate 105 to the integrated mirror 201, are made of non-magnetic or weakly magnetic materials, completely eliminating the Lorentz force interference of residual magnetic fields on the electron beam trajectory. Under the protection of a non-magnetic environment, the electron beam can be deflected and focused strictly according to the preset path, avoiding problems such as pattern distortion, increased overlay error or decreased resolution caused by magnetic field disturbance.

[0047] In summary, this embodiment deeply integrates precision mechanical structures, multi-dimensional sensing feedback, and a non-magnetic material system into the entire electron beam exposure process, achieving closed-loop accuracy assurance from static support and coordinate calibration to dynamic compensation. It should be noted that although this embodiment uses specific accuracy values ​​and process flows as examples, in other embodiments, as long as the layered decoupling architecture, wedge-type Z-axis adjustment principle, and integrated multi-functional design of the integrated mirror of this invention are adopted, even if the specific accuracy indicators or process sequence are adjusted, as long as high-precision positioning and high stability of the mask in a vacuum non-magnetic environment can be achieved, they all fall within the protection scope of this invention.

[0048] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A precision workpiece stage for an electron beam exposure apparatus, characterized in that, It includes an upper motion stage (100) and a lower slide stage (200). The motion table (100) includes a mounting base plate (105), a Y-axis motion mechanism, and an X-axis motion mechanism arranged sequentially from bottom to top; The stage (200) includes a connecting base plate (213), a middle plate (214), a top plate (215), and an integrated mirror (201) arranged sequentially from bottom to top. The integrated mirror (201) is used to support the mask plate (300). The connecting base plate (213) is connected and fixed to the X-axis motion mechanism. The top plate (215) and the connecting base plate (213) are provided with a Z-axis adjustment mechanism to realize the position adjustment of the mask plate (300) in the X, Y and Z directions.

2. The precision workpiece stage for an electron beam exposure apparatus according to claim 1, characterized in that, The Y-axis motion mechanism includes a Y-axis motion plate (102) and a Y-axis guide rail assembly (104). The Y-axis motion plate (102) is connected to the mounting base plate (105) via the Y-axis guide rail assembly (104), and a Y-axis drive connection assembly (107) is provided on one side of the Y-axis motion plate (102) to connect to an external drive source.

3. The precision workpiece stage for an electron beam exposure apparatus according to claim 2, characterized in that, The X-axis motion mechanism includes an X-axis motion plate (101) and an X-axis guide rail assembly (103). The X-axis motion plate (101) and the Y-axis motion plate (102) are connected by the X-axis guide rail assembly (103), and an X-axis drive connection assembly (106) is provided on one side of the X-axis motion plate (101).

4. The precision workpiece stage for an electron beam exposure apparatus according to claim 3, characterized in that, Both the mounting base plate (105) and the Y-axis motion plate (102) are provided with limiting blocks (108). The limiting blocks (108) on the side of the mounting base plate (105) are used to limit the displacement of the Y-axis motion plate (102), and the limiting blocks (108) on the side of the Y-axis motion plate (102) are used to limit the displacement of the X-axis motion plate (101).

5. The precision workpiece stage for an electron beam exposure apparatus according to claim 3, characterized in that, The Z-axis adjustment mechanism includes an elastic thin plate (206), a Z-axis support column (207), a wedge block (208), and a bearing seat assembly (210); the Z-axis support column (207) is mounted on the connecting base plate (213), and the Z-axis support column (207) is connected to the top plate (215) through the elastic thin plate (206); the bearing seat assembly (210) is mounted through the top plate (215), and the top surface of the bearing seat assembly (210) is connected to the integrated mirror (201), the bearing of the bearing seat assembly (210) rests on the inclined surface at the top of the wedge block (208), and the flat surface at the bottom of the wedge block (208) is connected to the intermediate plate (214); The connecting base plate (213) and the intermediate plate (214) are connected by a guide rail assembly (209). The connecting base plate (213) is provided with a piezoelectric ceramic motor (211), and the output end of the piezoelectric ceramic motor (211) is connected to the side of the intermediate plate (214). When the piezoelectric ceramic motor (211) drives the intermediate plate (214) to move in the X direction, the wedge block (208) moves horizontally in the X direction, and the bearing of the bearing seat assembly (210) slides along the inclined surface of the wedge block (208), thereby realizing the small displacement movement of the stage (200) in the Z direction.

6. The precision workpiece stage for an electron beam exposure apparatus according to claim 5, characterized in that, The connecting base plate (213) is also provided with a grating assembly (212), which is located on the side of the intermediate plate (214) to detect the displacement of the intermediate plate (214) along the X direction in real time.

7. The precision workpiece stage for an electron beam exposure apparatus according to claim 5, characterized in that, The X-guide rail assembly (103), Y-guide rail assembly (104) and rail assembly (209) all adopt cross roller rail assemblies.

8. The precision workpiece stage for an electron beam exposure apparatus according to any one of claims 1 to 7, characterized in that, The integrated mirror (201) has multiple support columns (203) of equal height evenly distributed on it to support the mask plate (300).

9. The precision workpiece stage for an electron beam exposure apparatus according to any one of claims 1 to 7, characterized in that, The integrated mirror (201) is also equipped with a Faraday cup (204) and multiple positioning marker blocks (205). The Faraday cup (204) is used to measure the size of the electron beam current, and the height difference between two adjacent positioning marker blocks (205) is 50±1μm.

10. The precision workpiece stage for an electron beam exposure apparatus according to any one of claims 1 to 7, characterized in that, The integrated mirror (201) has reflective surfaces (202) on its side along the X and Y directions to cooperate with the laser interference system to monitor and provide feedback on the position of the workpiece stage in real time.

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