Sub-nanometer scale, high-precision lithographic writing field splicing method and lithographic system using same

Abstract

The solution includes a photosensitive adhesive layer (2) coated on the surface of a wafer (1) to be photolithographed, and after the surface of the photosensitive adhesive layer (2) is exposed, a minute uneven structure is generated on the exposed graphics, and a nano-contact sensor (39) can recognize these uneven structure graphics and use them as in-situ alignment coordinate marks (8, 10, 44, 45). The position coordinates of the writing field before and after exposure and before and after the movement of the wafer (1) are compared to calculate the splicing offset, and a negative feedback control method is used to perform high-precision lithography splicing of the wafer (1), and the wafer workbench mechanical operation is performed. A sub-nanometer-scale, high-precision lithography writing field splicing method that overcomes the drawback of conventional non-in-situ, off-the-write-field blind open-loop lithography splicing technology, which is affected by movement accuracy and long-term drift of electron beam (17). A sub-nanometer-scale, high-precision writing field splicing lithography system, a pre-processed wafer (1), a method for measuring electron beam (17) drift, and a sub-nanometer-scale, high-precision photolithography writing field vertical splicing method.

Description

[Technical Field]

[0001] The present invention relates to photolithography technology in the manufacturing technologies of integrated circuits, optoelectronic devices, etc., specifically, precision alignment technology for positioning electron beam (here, electron beam is a general term for electron beam, photon beam, ion beam, or atomic beam) photolithography in horizontal and / or vertical splicing of graphics, lithography systems and wafers using the same, and in particular, a sub-nanometer-scale, high-precision lithography write field splicing method based on space in situ closed-loop control technology for write field splicing in electron beam photolithography systems, lithography systems, and preprocessed wafers. [Background technology]

[0002] The growth of microelectronics and optoelectronics has led to rapid growth in the integrated circuit chip, integrated optics, and quantum computing industries, which form the basis of the core devices and chips of the modern computer, display, and entire information industry. Currently, the technology node of the modern chip industry has reached 5nm or below.

[0003] Photolithography technology is essential for manufacturing micro- and nano-devices such as chips. Photolithography technology includes electron beam photolithography, conventional optical photolithography, extreme ultraviolet (EUV) lithography, ion beam photolithography, and scanning probe lithography. Without these key photolithography technologies, it would be impossible to manufacture precise photolithography graphics or comprehensive micro- and nano-device structures (including integrated circuit chips and optoelectronic integrated chips).

[0004] Currently, multi-mask graphics technology is enabling the semiconductor industry to significantly increase the integration level of integrated circuits while also increasing the complexity of chip manufacturing. At the 28nm technology node, chips require 40-50 masks (assuming a 20mm aspect ratio). This translates to 60 masks for a 10nm technology node chip at the 14nm technology node (assuming a 20mm aspect ratio). At the 7nm technology node or smaller, chips require 80-85 masks, and at the 5nm technology node, an additional 100 masks and 120 photolithography steps are required. Addressing the alignment error accuracy of splicing in photolithography and the alignment consistency of these masks remains a major challenge in the fabrication of templates for large wafer and chip dimensions. This calls for more precise chip photolithography manufacturing technology (down to 1nm). Until now, the world has not had such high-precision photolithography manufacturing technology.

[0005] Conventional electron beam lithography (EBL) systems are nanometer-level photolithography techniques widely used in scientific research, sample production, and industrial template fabrication and production. Because electron beam photolithography systems only have a limited exposure field, large graphics must be divided into multiple adjacent fields. The wafer workbench must be moved to expose each field individually, and each field must be offset to ensure precise alignment with the splicing. In reality, mechanical movements and electron beam drift are not without error, and the error is not insurmountably small, so this error is called splicing error.

[0006] As used herein, wafer includes on-wafer, wafer, and portions of non-wafer based samples.

[0007] Before photolithography, a wafer is coated with a flat photosensitive adhesive layer, with no other structures on its surface. The surface of the photosensitive adhesive layer is scanned and exposed with a preset electron beam graphic, which initiates a chemical reaction in the photosensitive adhesive layer. The exposed graphic portion on the surface of the photosensitive adhesive layer is either retained or removed by chemical development, resulting in the electron beam-exposed graphic becoming the photosensitive adhesive layer graphic, which is ultimately transferred to the wafer by etching. Due to the lack of in-situ feedback (where in-situ refers to the coordinate position within the scanning writing field of the electron beam), conventional electron beam photolithography is an open-loop controlled "blind operation." This means that the electron beam cannot scan the wafer surface once the photosensitive adhesive layer is coated. This is because scanning the electron beam means exposing the photosensitive adhesive layer on the wafer. After the photosensitive adhesive layer is developed, any improvements in the photolithography process are too slow and irreversible, as the exposed location is only visible if it is in an incorrect location. The splicing quality of the written field graphics is measured by exposure and cannot be fed back to the workbench for movement calibration. In addition, the mechanical movement of the wafer workbench is too loose to adapt to the drift of the electron beam and overcome the resulting errors.

[0008] Therefore, the current approach to further improving the precision level of photolithography technology is to find a method for performing in-situ measurements and calibrating alignment errors throughout the entire process of photolithography exposure of the required graphics. However, to date, such a method has not been found, and there are no lithography systems available to implement this method.

[0009] In order to more conveniently and fully disclose and easily understand the technical problem to be solved by the present invention, the terms and operating principles will be explained for a sufficient explanation and easy understanding before describing the technical solutions and examples of the present invention.

[0010] The electron beam described in the present invention may be a Gaussian beam or a modified beam. Unless otherwise specified, the electron beam below refers to a Gaussian electron beam, and if the modified beam spot is not large, the modified beam may also be used.

[0011] Figure 1 shows the principle of the Gaussian beam exposure process. The Gaussian electron beam is focused on the surface of the photosensitive adhesive layer for exposure. The coordinates of the electron beam refer to the coordinates of the surface position of the photosensitive adhesive layer that is targeted by the electron beam, and the electron beam appears at the position where it will be exposed on the surface of the photosensitive adhesive layer.

[0012] To keep track of electron beam coordinates properly, here are some special coordinate definitions: CPJE is the coordinate at the photosensitive adhesive layer that has just been exposed to the electron beam, and CPTE is the coordinate at the point that is aimed at the electron beam but not exposed. Both coordinates have the same feature: the electron beam coordinate is attached to the coordinate at the surface location of the photosensitive adhesive layer.

[0013] For electron beam lithography systems, errors due to wafer workbench movement can be adjusted and compensated for by deflecting the electron beam, and errors can be located by alignment marks on the wafer.

[0014] In electron beam photolithography, photolithographic graphics are exposed and transferred to a photosensitive adhesive layer, and then transferred to a wafer using photolithographic graphics etching. It should be noted that in conventional techniques, the photosensitive adhesive layer applied to the wafer results in a smooth wafer surface without any graphic structure. Because the wafer's photosensitive adhesive layer is photophobic, the electron beam cannot image the surface with radiation (exposure) until exposure, and it cannot penetrate the photosensitive adhesive layer to capture the graphics on the wafer underneath. Furthermore, lithography systems require precise alignment between exposure and graphic positioning. While the accuracy of this positioning is limited by the tolerances of each system and its surrounding elements, a fundamental challenge lies in the open-loop control of most lithography systems. That is, the position of the electron beam on the wafer cannot be traced before or during exposure.

[0015] Conventional electron beam photolithography alignment has an inherent flaw: when alignment marks (Figure 2) are far from the writing field, these alignment marks can only be used to achieve indirect alignment during splicing of the electron beam photolithography writing field by moving the wafer workbench, which is not precise, direct in-situ alignment in the writing field, leading to alignment errors. Precise in-situ alignment refers to alignment in which the electron beam is aimed at the alignment mark in the writing field. Typically, the overlap positioning accuracy of the electron beam in the writing field of the exposed area is within 1 nm, and the accuracy of the electron beam deflection to any coordinate position in the writing field of the exposed area is within this range. Therefore, the concept of so-called in-situ alignment can be extended to include "alignment of the electron beam with the alignment mark in the writing field of the exposed area can also be considered in-situ alignment."

[0016] For splicing alignment between writing fields, specialized alignment marks must be used to ensure the alignment of wafer graphics coordinates with electron beam coordinates. Because the electron beam cannot use the imaging capabilities of an electron microscope on surfaces coated with a photosensitive adhesive layer and cannot find the corresponding wafer graphics coordinates under the pre-exposure photosensitive adhesive layer, a special coordinate position outside the writing field must be selected on the wafer for the electron beam to determine and align the wafer graphics. The electron microscope must be moved from a special coordinate position far away from the writing field to the electron beam's irradiation exposure point on the wafer workbench. Position errors due to mechanical movement accuracy and electronic drift significantly limit the accuracy of current wafer writing field splicing.

[0017] Big Graphics Electron Beam Lithography

[0018] Large-area graphics lithography transfers electron beam graphics designs onto wafers, and these photolithographic graphics can meet a variety of application needs. These applications have a huge market potential. These applications include optical gratings, large-area Fresnel lenses, extreme ultraviolet photolithography masks for integrated circuits, distributed feedback lasers, semiconductor laser arrays, photonic crystals, and mass storage, and the graphics dimensions (lengths) can range from 10mm to over 300mm.

[0019] Because the writing field is very small, in the case of large-area photolithography, photolithography of one writing field cannot be completed in one go, so many electron beam writing fields need to be spliced, and the splicing error accumulates and becomes a serious system error, so the requirement for splicing error accuracy is very high.

[0020] Alignment marks

[0021] Conventional electron beam lithography systems can write or expose graphics with only a limited writing field without causing distortion of the graphics being written. Typically, this writing field has dimensions ranging from 100 microns x 100 microns to 1 mm x 1 mm. This size is too small for many graphics applications, which require dimensions ranging from 20 mm x 20 mm to 200 mm x 200 mm. For larger graphics, the only option is to splice these small writing fields one by one into larger writing field graphics by moving the wafer workbench. This results in significant cumulative alignment splicing errors between one writing field graphic and its neighboring graphics.

[0022] Because the entire wafer is covered with a photosensitive adhesive layer and both are "useful" areas, alignment in electron beam photolithography typically must be performed outside the writing field or outside the entire wafer, i.e., at the wafer edge. In particular, when selecting alignment coordinates at the entire wafer edge, alignment coordinates are placed in "useless" areas far from the writing field. These alignment coordinates far from the writing field are accepted by the industry because they are not located in the wafer areas where graphic exposure is required. Therefore, they can be exposed to an electron beam to create alignment coordinate marks (hereinafter referred to as "alignment marks"), or they can be repeatedly observed and exposed to the electron beam of an electron microscope.

[0023] These alignment coordinate marks are aligned by the movement of the wafer workbench, and the precision of the movement control of the wafer workbench determines the accuracy of the write field splicing error. High precision requirements for write field splicing require an expensive, high-precision laser moving workbench. This is because the main positioning accuracy offsets come from the wafer workbench positioning error in the movement direction, the relationship changes in other wafer coordinate directions due to this movement, and the electron beam drift caused by the long-term movement required for these movements.

[0024] Figure 3 shows the conventional "out-of-field" alignment marks (12 at the edge of the wafer, 14 between the writing fields, and a hitherto unused "in-field" (IA) mark 13 that can be scanned with an electron beam).

[0025] The wafer edge alignment marks 12 are set at the edge of the wafer far from the writing field.

[0026] The alignment marks 14 between the writing fields are set between the writing fields (if there is space between the writing fields). In fact, in many cases, no space between the writing fields is allowed. Optical gratings or Fresnel lenses are examples of this. Optical grating lines must not be cut to leave spaces.

[0027] Without the movement of the wafer work bench, it is not possible to aim the electron beam irradiation at the new writing field, either at alignment mark 12 or alignment mark 14. The movement of the work bench leads to movement alignment errors and also leads to longer alignment times, which causes electron beam drift due to various unstable factors (temperature drift, humidity drift, etc.; see Figure 7).

[0028] When alignment marks are placed in the writing field where the electron beam can scan, alignment does not require movement of the wafer workbench. Using such marks eliminates the need for long-term alignment adjustment of the electron beam and reduces electron beam drift. This type of alignment mark is called an "in-field mark" (IA mark). However, because conventional technological solutions require a large area, the industry has not yet demonstrated that in-field marks can thoroughly solve the difficult problem of writing field splicing accuracy.

[0029] If the in-field mark 13 could be reduced to a few nm to a few hundred nm, the required area would be very small and it would be very practical, but no solution to this problem has been found to date, and there is no technology that can reduce the in-field mark to a few nm to a few hundred nm and recognize it.

[0030] If this extremely small in-field mark 13 is sufficiently small in the electron beam writing field and very close (for example, several nm to several tens of nm) to the coordinates on the surface of the photosensitive adhesive layer targeted by the electron beam, this in-field coordinate becomes the in-situ alignment coordinate mark (ISA mark) described in the present invention.

[0031] When the in-field mark 13 is exactly at the electron beam coordinate, i.e., the coordinates of the exposed graphics on the photosensitive adhesive layer wafer exactly overlap with the exposure coordinates (target coordinates) of the electron beam, this in-field coordinate becomes the "overlapping alignment coordinate" mark (OA mark) described in this invention.

[0032] The overlap position accuracy of the electron beam in the writing field (typically within 1 nm) is so high that the marks in the writing field can be considered approximately as in situ alignment marks.

[0033] 3D Alignment Marks

[0034] This technology uses electron beam radiation to recognize and image alignment marks. These alignment marks are typically planar, i.e., 2D. However, 3D marks on the surface of the photosensitive adhesive layer and wafer can also be used as alignment marks. For example, measuring the peak or trough position of a 3D mark can accurately determine alignment coordinates. Typically, the unevenness on the wafer surface creates an unevenness on the surface of the covering photosensitive adhesive layer, and the unevenness and position of such surface can be detected.

[0035] Electron beam induced photosensitive adhesive layer changes

[0036] Electron beam induced changes ( EBIC Electron Beam Induced Change (EBIC) refers to the change in the chemical and / or physical properties of a photosensitive adhesive layer at the location of electron beam exposure. Chemical changes include a chemical reaction on the surface of the photosensitive adhesive layer caused by the electron beam, causing the irradiated portion of the photosensitive adhesive layer to change from an insoluble state to a soluble state upon development (positive glue), or a soluble state to an insoluble state upon exposure (negative glue). Physical changes in a photosensitive adhesive layer caused by electron beam exposure include minute changes in the geometric dimensions of the surface of the photosensitive adhesive layer. For example, swelling or shrinking on the sub-nanometer or nanometer scale creates a textured structure (see Figure 2). When an electron beam is exposed and transfers the graphic information of the electron beam to the photosensitive adhesive layer, the textured structure of the photosensitive adhesive layer changes.

[0037] One method for generating 3D marks involves electron-beam-induced property transformation of a photosensitive adhesive layer, which causes physical changes in the photosensitive adhesive layer due to exposure to an electron beam, including minute geometric dimensional changes on the surface of the photosensitive adhesive layer. For example, the photosensitive adhesive layer may expand or contract on a sub-nanometer or nanometer scale, forming a relief structure. As shown in Figures 2a and 2b, upon exposure, the photosensitive adhesive layer graphics expand or contract in height, forming 3D geometric height graphics. Such deformations can be detected and recognized on a sub-nanometer scale using a nano-contact sensor (height-sensitive sensor).

[0038] Another method for creating 3D marks is to pre-set 3D structures on the wafer, such as 3D protrusions, mini-cones, mini-pyramids, or mini-contact points, whose diameter scale ranges from a few nanometers to a few tens of nanometers. These mini-structures can be achieved by electron beam photolithography or electron beam induced deposition techniques. 3D marks 18 and 19 in Figure 4 are such pre-set 3D protrusions. Hereafter, they are referred to as wafer protrusion alignment marks (HAMW marks).

[0039] For example, a 3D raised alignment mark 19 coated with a thin photosensitive adhesive layer, with a thickness of 10 nm to 300 nm, creates a 3D structure on the surface of the photosensitive adhesive layer at the wafer 3D raised alignment mark 19 (HAMW). The height of this 3D structure is appropriately several nanometers to several tens of nanometers, accurately indicating the position (HAMR) of the 3D alignment mark 18 on the surface of the photosensitive adhesive layer. This position is exactly the same vertically as the vertically lower wafer 3D alignment mark. This method allows for accurate determination of the wafer graphics abscissa. Importantly, this abscissa can be located within the writing field. By placing these 3D alignment marks, the alignment precision can be determined, eliminating the need for precision in wafer workbench movement, allowing for the use of a workbench with lower movement positioning precision. For example, a workbench with a positioning accuracy requirement of 1 nm can be changed to a workbench with a positioning accuracy of 1000 nm, which significantly reduces the cost of the workbench.

[0040] Lateral Stiching Alignment (LSA) Error

[0041] One of the major challenges for electron beam lithography systems is the large splicing error between the previous and next adjacent writing fields (Figures 5a-5c). To expose large-area graphics, it is necessary to splice the writing fields one by one by moving the wafer workbench to form large graphics. In conventional electron beam photolithography technology, splicing between writing fields is achieved by moving the wafer workbench. The positioning accuracy of a new writing field depends to a large extent on the positioning accuracy of the workbench and the drift of the electron beam. Typically, expensive laser workbenches with extremely high precision, capable of positioning accuracy of several nanometers or better, are used. However, even these highly accurate laser workbenches are extremely sensitive to environmental changes (such as temperature and humidity), making it difficult to achieve or replicate nanometer-scale precision.

[0042] If the splicing error between two adjacent writing fields is typical, the error is + / - 20 nm for a 100 kV e-beam lithography system and + / - 35 nm for a 30 kV e-beam lithography system. A 35 nm writing field splicing error would mean a worst-case splicing error of 700 nm, making this optical grating array completely useless. Even smaller splicing errors (e.g., within 1 nm) are particularly necessary for such large-area, high-precision applications.

[0043] vertical direction Vertical Alignment (VA) Error

[0044] Vertical alignment involves aiming the electron beam at the writing field 22 (take photolithography of an optical grating 23 as an example) in the exposure area, aligning it with the alignment coordinates of the previous writing field 22' (Figures 6a-6b). Achieving this goal is difficult because the wafer being exposed is often covered and separated by a thin photosensitive adhesive layer. Typically, photosensitive adhesive layers have thicknesses ranging from 10 nm to 500 nm. The electron beam is blocked by the photosensitive adhesive layer, preventing it from seeing the underlying graphic structure on the wafer, making it impossible to align the graphics on the wafer. Therefore, typically, alignment marks 24 are located outside the electron beam writing field. Aligning these marks requires workbench movement, and in the open-loop control of electron beam photolithography, these alignment marks outside the writing field are not direct alignment; in other words, they are not in-situ alignment. Workbench movement introduced an error between the writing field 22 before the wafer moved and the writing field 22' after the wafer moved.

[0045] Alignment error within one of the writing fields

[0046] As mentioned above, current electron beam lithography systems require alignment marks outside the writing field or at the wafer edge. However, these alignment coordinate marks are not direct alignment (i.e., indirect alignment), are not accurate, are not in situ, and are time-consuming. An improvement method is to place alignment marks 13 within the writing field. However, a practical problem is that if an alignment mark is placed within the writing field, it will still be covered by the photosensitive adhesive layer and will not be visible to the electron beam. Therefore, in the prior art, the method of "placing alignment marks within the writing field" is not remembered, and even if it is remembered, it is not used.

[0047] Representation of the electron beam spot (Figure 7)

[0048] Surface irregularities (electron beam induced changes) on the surface of electron beam sensitive adhesive layers EBIC ) Graphically reverse the electron beam performance and calibrate it

[0049] a): Measurement of the electron beam spot. The exposed irregularities left by the electron beam on the surface of the photosensitive adhesive layer are exactly the shape of the electron beam spot.

[0050] b): Drift of the electron beam over time. The exposed topography left by the electron beam on the surface of the photosensitive adhesive layer can be measured over time with a contact-sensing system. This drift can be used as a compensation calibration for the electron beam writing field, but the prior art does not appear to have disclosed a similar concept.

[0051] In summary, current photolithography technology involves coating the surface of the wafer 1 to be processed (exposed) with an opaque photosensitive adhesive layer 2. Therefore, alignment coordinate marks must be placed outside the writing field, particularly on the entire outer edge of the wafer (i.e., not in situ), so that the electron beam is exposed away from the direct alignment field. This results in mechanical displacement in each writing field, resulting in mechanical errors, errors in the splicing of all writing field graphics, and exposure errors due to long-term drift of the electron beam over time. The resulting system errors are not in situ but are controlled by blind open-loop control, meaning they cannot be compensated for or corrected by a system. Therefore, the splicing errors of conventional technologies are too large and insurmountable. Currently, traditional lithography systems are limited by the precision of their electro-mechanical processing, making it difficult to improve precision and expensive. Summary of the Invention [Problem to be solved by the invention]

[0052] To overcome the above-mentioned deficiencies in the prior art, the present invention must solve the following problems.

[0053] 1. A sub-nanometer scale, high-precision lithography writing field splicing method is provided that performs photolithography processing by accurately detecting the exposure offset of the writing field in real time, controlling the splicing in an automatic closed loop, and making corrections, without being limited to the electromechanical processing accuracy of conventional wafer workbenches.

[0054] 2. A lithography system for processing wafers by this method is provided.

[0055] 3. Providing a pre-processed wafer for carrying out the above method.

[0056] 4. Provide a method for measuring electron beam drift.

[0057] 5. Sub-nanometer scale, high-precision photolithography writing field vertical direction The present invention provides a splicing method for the above. [Means for solving the problem]

[0058] 1. A sub-nanometer scale, high-precision lithography writing field splicing method, including the following steps:

[0059] Step 1: The main body of the lithography system is equipped with a mesa, an electron microscope tube and its electron gun, a movable wafer workbench, and at least one nano-contact sensor for controlling the movement of the wafer workbench. Computer Numerical ControlA drive device is installed, and a photosensitive adhesive layer is applied to the entire wafer before the wafer is placed in the lithography system. The area scanned by the electron beam is the exposure area, and the exposure area is divided into several writing fields. Each writing field in the photosensitive adhesive layer has an in-situ alignment coordinate mark that appears in a predetermined shape when exposed in a specific exposure area. The writing fields are successively designated as writing field No. 1, writing field No. 2, ..., writing field No. n.

[0060] Step 2: Place the wafer coated with the photosensitive adhesive layer on the workbench, place the writing field No. 1 of the wafer on the exposure area, and align the electron beam tube of the electron microscope vertically with the exposure area, then focus the electron beam on the writing field.

[0061] Step 3: After exposing a portion of the wafer in the writing field No. 1 in the exposure area, a chemical reaction occurs in the photosensitive adhesive applied to this portion of the wafer, causing changes due to the electron beam to produce at least one or one group of relief structures that constitute the graphics. The specific shape of this relief structure is the characteristic shape of the pre-installed in-situ alignment coordinate mark, and the coordinate values ​​of its characteristic points in the exposure area are used as in-situ alignment coordinates.

[0062] Step 4: Start the nano-contact sensor to measure the surface shape of the uneven structure, and then match it with the preset shape to recognize the alignment coordinate mark, and determine and store its coordinate value on the surface of the work bench.

[0063] Step 5: To prepare for the exposure of writing field No. 2, the moving workbench moves the moving wafer horizontally and / or vertically, moving the just-exposed writing field No. 1 area out of the exposure area and taking writing field 22-1' to make space for writing field No. 2 of the wafer entering the exposure area.

[0064] Step 6: Start the nano-contact sensor to recognize the alignment coordinate mark in writing field No. 1 moved from the above exposure area, and after it moves, determine and store the position coordinate of writing field No. 1 on the surface of the workbench.

[0065] Step 7: Using the data of the alignment coordinate mark in the moved writing field No. 1 as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the writing field movement, and determine the coordinate calibration value for the entire next exposure area of ​​the electron beam.

[0066] The coordinates of the error-calibrated writing field No. 2, which is located adjacent to the writing field No. 1 moved from the exposure area, are set to C1R1', that is, coordinates (XC1R1', YC1R1'). This is also the new coordinate that must be seamlessly spliced ​​to the moved writing field No. 1 of the writing field No. 2 located at the exposure area. That is, (X C2L1´ , Y C2L1´ ):X C2L1´ =X C1R1´ , Y C2L1´ =Y C1R1´

[0067] At this time, the electron beam is adjusted to the coordinates C2L1 for writing field No. 2, i.e., coordinates (X C2L1 , Y C2L1), this coordinate point must be closely attached to the edge coordinate C1R1' of the moving writing field No. 1 by applying a deflection voltage to the electron beam, and splicing calibration and exposure must be performed for the coordinate of writing field No. 2, so that the related coordinate point of the calibrated writing field No. 2 is C2L1', and the coordinate difference between C2L1' and C2L1 is as follows. ΔX1=X C2L1´ -X C2L1 =X C1R1´ -X C2L1 Δ Y 1= Y C2L1´ - Y C2L1 = Y C1R1´ - Y C2L1

[0068] Since the writing field No. 2 and its coordinates cannot be obtained when the work bench is not moving and not exposed, the entire electron beam drift that the electron beam exposes writing field No. 1 and exposed writing field No. 2 in the exposed area is ignored, and the coordinates of writing field No. 1 in the exposed area are the X coordinates of the exposure of writing field No. 1 in the exposed area until writing field No. 2 is exposed and calibrated. C2L1 =X C1L1 , Y C2L1 =Y C1L1 This coordinate can be detected by the uneven structure caused by exposure on the surface of the photosensitive adhesive layer after the writing field No. 1 is exposed and before the work bench is moved, and the coordinate difference that needs to be compensated for in all calibrations of the electron beam coordinate points of the writing field No. 2 is obtained. ΔX1=X C1R1´ -X C1L1 ΔY1=Y C1R1´ -Y C1L1

[0069] Step 8: Adjust the deflection voltage of the electron beam tube according to the coordinate difference that needs to be compensated for, and calibrate the exposure area of ​​the electron beam so that the splicing coordinate of the writing field No. 2 of the wafer entering the exposure area is calibrated to the splicing coordinate adjacent to the shifted writing field No. 1, and the calibrated splicing coordinate of the writing field No. 2 achieves seamless splicing with the shifted writing field No. 1.

[0070] Further measures may include the following steps:

[0071] Step 9: Electron beam exposure is performed on the wafer portion of writing field No. 2 that has been moved to the calibrated exposure area of ​​the electron beam exposure coordinates, causing the photosensitive adhesive applied to the exposed portion of the wafer to undergo a chemical reaction and revealing alignment coordinate marks in this writing field that feature the preset, determined uneven structure.

[0072] Step 10: Start the nano-contact sensor to recognize the alignment coordinate mark according to the preset shape, and determine and store the position coordinates of the feature coordinate point in the calibrated writing field No. 2 on the surface of the workbench.

[0073] Step 11: Pre-exposure preparation for writing field No. 3 is performed, and the moving work bench again moves the moving wafer horizontally and / or vertically, moving the previously moved writing field No. 1 and the just-exposed calibrated writing field No. 2, so that the just-exposed calibrated writing field No. 2 is moved from the exposure area. Due to the work bench movement, the position coordinates of the previously moved writing field No. 1 change and become the twice-moved writing field No. 1, and its position coordinates change from (C1Lx´, C1Rx´) to (C1Lx´´, C1Rx´´), and the position coordinates of the calibrated and then moved writing field No. 2 from the exposure area change from (C2Lx´, C2Rx´) to (C2Lx´´, C2Rx´´), and this writing field No. 2 becomes the moved writing field No. 2, making space for the next wafer to be moved from writing field No. 3 to the exposure area.

[0074] Step 12: Start the nano contact sensor again to recognize the alignment coordinate mark in writing field No. 2 transferred from the above exposure area, and determine the position coordinates (C2L1´´, C2L2´´, C2L3´´, C2R1´´, C2R2´´, C2R3´´) stored on the surface of the workbench.

[0075] Step 13: Using the data of the alignment coordinate mark in the moved writing field No. 2 as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the movement, and determine the calibration values ​​Δ×2 and ΔY2 of the writing field in the next exposure area of ​​the electron beam.

[0076] The coordinates of the writing field No. 3, which is adjacent to the writing field No. 2 that has been moved from the exposure area, are C2R1', i.e., the coordinates (X C2R1´´、 Y C2R1´´ ) This is also the calibration coordinate for seamlessly splicing the exposed writing field No. 3 to the moved writing field No. 2. That is, (X C3L1´´、 Y C3L1´´ ):X C3L1´´ =X C2R1´´、 Y C3L1´´ =Y C2 R1´´

[0077] At this time, the coordinate of the electron beam for writing field No. 3 in the exposed area is C3L1, i.e., the coordinate (X C3L1 , Y C3L1 ), the coordinate difference with the moving writing field No. 2 exposed according to splicing is this coordinate point, and the splicing exposure is performed by closely adhering to the edge C2 R1' of the moving writing field No. 2 by the electron beam additional deflection voltage, and the related coordinate point of the calibrated writing field No. 3 is C3 L1', and the coordinate difference between C3 L1' and C3 L1' is as follows. Δ×2 =X C3L1´´ -X C3L1´ =X C2R1´´ -X C3L1´ ΔY2=Y C3L1´´ -Y C3L1´ =Y C2R1´´ -Y C3L1´

[0078] Expose writing field No. 2 and writing field No. 3 in the exposure area. Ignore the entire electron beam drift in the exposure area, and write field No. 3 is the coordinate of the exposure area until the exposure coordinate is calibrated. X coordinate of the exposure of writing field No. 2. C3L1´ =X C2L1´ , Y C3L1´ =Y C2L1´ This coordinate is made to be equivalent to the coordinate of the electron beam at all the exposed points of the writing field, and can be detected by the uneven structure caused by the exposure of the surface of the photosensitive adhesive layer from the time when the writing field No. 2 is exposed until the work bench is moved, thereby obtaining the coordinate difference that needs to be compensated for in the coordinate calibration of the electron beam at all the exposed points of the writing field. Δ×2 =X C2R1´´ -X C2L1´ ΔY2=Y C2R1´´-Y C2L1´

[0079] Step 14: Adjust the deflection voltage of the electron beam tube (32) according to the obtained calibration value, and calibrate the exposure area of ​​the electron beam so that the coordinates of all exposure points of writing field No. 3 on the wafer are consistent with the splicing coordinates of the moved writing field No. 2 and the adjacent writing field No. 3 to achieve seamless splicing.

[0080] Step 15: Repeat to complete the entire exposure, transfer and splicing of the entire writing field area of ​​the wafer.

[0081] Furthermore, the electron beam may be an ion beam, a photon beam, or an atomic beam.

[0082] The nano-contact sensor between force microscope The sensor may be a needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor, or a combination of these.

[0083] The wafer may include a complete wafer, a portion of a wafer, or non-wafer material that is in need of processing by photolithographically written field splicing.

[0084] The in-situ alignment coordinate marks are planar graphics marks.

[0085] There may be one, two, three, four, five, six or more of said planar graphic marks on one of the planes.

[0086] The planar graphic marks include graphic marks resulting from minute geometric structure changes caused by the electron beam inducing the photoresist surface.

[0087] The in-situ alignment coordinate marks are three-dimensional marks.

[0088] The three-dimensional mark may be pyramidal or conical, and there may be one, two, three, four, five, six or more of such marks on one of the planes.

[0089] There may be one, two, three, four or more of said nano-touch sensors around said exposed area.

[0090] The nano-touch sensor has one or more lever-type sensor arms and needle-tip guide contactors aligned with the touch arms.

[0091] The electron beam is a Gaussian beam.

[0092] The electron beam is a modified beam.

[0093] and a sub-nanometer-scale, high-precision writing field splicing lithography system including a stationary device and a mesa on the device, an electron microscope on top of the mesa, at least one nano-contact sensor, and a movable wafer workbench, an electron beam tube on the electron microscope, and a device for pulling the mesa on the wafer workbench to perform forward and backward and / or left and / or right and / or up and down movement and angle change. Computer Numerical Control There is a drive unit.

[0094] The lithography system includes a graphics generator, an electron beam control system, and a wafer workbench. Computer Numerical ControlThe system also includes a control computer connected to the drive device, and the nano-contact sensor transmits the in-situ alignment coordinate mark signals and / or electron beam drift signals collected and detected on the wafer to a graphic generator under the control of the control computer, and the graphic generator transmits a processed and calibrated electron beam scan control signal to an electron beam control system under the control of the control computer, and the electron beam control system controls a shutter of a focus system of an electron beam tube and a deflection coil for controlling the deflection of the electron beam.

[0095] Further technical measures that may be considered for adoption include:

[0096] There is also a secondary electron imaging signal acquisition device that feeds back a secondary image scanned by the electron beam collected in the electron beam tube to the control computer through the electron beam control system.

[0097] The nano-contact sensor between force microscope The sensor may be a needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor, or a combination of these.

[0098] The nano-contact sensor has a lever-type sensor arm and a needle-tip induction contactor on the touch arm.

[0099] Each of said touch arms has one or more stylus tip guide contactors.

[0100] Each of said touch arms has at least one row of tip-guided contactors, each row having one or more tip-guided contactors.

[0101] There are two rows of the nano-contact sensors, four per row, two rows on each side of the electron beam tube.

[0102] The electron beam tube is aimed at an exposure area of ​​a wafer on the workbench.

[0103] 3. A pre-processed wafer coated with a photosensitive adhesive layer to be exposed, in which the wafer and / or the photosensitive adhesive layer are exposed to an electron beam in the writing field area, and the wafer and / or the photosensitive adhesive layer are provided with in-situ alignment coordinate marks with a predetermined shape consisting of concave and / or convex portions, for the nano-contact sensor to recognize the in-situ coordinates.

[0104] The in-situ alignment coordinate marks are planar graphics marks.

[0105] There may be one, two, three, four, five, six or more of said planar graphic marks on one of the planes.

[0106] The above-mentioned planar graphic marks are graphic marks that are produced by minute geometric structure changes caused by the electron beam inducing the photoresist surface.

[0107] The in-situ alignment coordinate marks are three-dimensional marks.

[0108] The three-dimensional marks may be one, two, three, four, five, six or more on one plane.

[0109] The wafer may include a complete wafer, a portion of a wafer, or non-wafer material that is in need of processing by photolithographically written field splicing.

[0110] 4. A method for measuring electron beam drift is provided, which includes the following steps: a mesa, an electron microscope tube and its electron gun, a movable wafer workbench, and a nano-contact sensor are installed in the main body of a lithography system; Computer Numerical ControlA drive device is installed, a photosensitive adhesive layer is coated on the wafer, an electron gun is used to emit an electron beam, the focus is placed on the photosensitive adhesive layer, and the photosensitive adhesive layer is exposed to light, so that the exposure causes a minute change in the geometric shape of the uneven structure induced by the electron beam on the surface of the photosensitive adhesive layer, and this minute change is detected, the drift of the focus over time is traced, and the coordinate values ​​and drift amount of the drift trajectory of the electron beam over time are recorded.

[0111] Furthermore, the method also includes the following steps: calculate the exposure coordinate value and calibration compensation difference value of the electron beam according to the time drift during the period from start to end according to the coordinate value and drift amount of the electron beam drift trajectory according to the recorded time, and determine the calibration coordinate of the next writing field exposure.

[0112] 5. Sub-nanometer scale, high-precision photolithography writing field vertical direction A splicing method is provided, which comprises: forming a wafer 3D alignment mark with a protruding structure on a wafer to be photolithographically processed, applying a photosensitive adhesive layer thereon, and forming a corresponding protruding 3D alignment mark on the photosensitive adhesive layer at the position where the 3D alignment mark is located; then, using a wafer workbench, transferring the wafer with the 3D alignment mark to a writing field area where an electron beam can be exposed; aligning the electron beam with the 3D alignment mark on the photosensitive adhesive layer for point exposure, resulting in an actual offset 3D mark at a location other than the exposed point on the photosensitive adhesive layer; measuring the actual coordinate values ​​of the 3D alignment mark and the offset 3D mark using a nano-contact sensor on the photosensitive adhesive layer; and calculating a calibration value for the exposure area of ​​the writing field; vertical direction controlling the electron gun to achieve precise alignment and exposure of vertical direction Achieve precise splicing. [Effects of the Invention]

[0113] In the lithography system according to the technical solution of the present invention, after exposing the wafer in the writing field portion in the exposure area with an electron beam, an in-situ alignment coordinate mark with a predetermined shape consisting of a concave and / or convex shape appears on the wafer in the writing field portion, and a nano-contact sensor in the lithography system thereby recognizes and records the in-situ coordinates on the wafer in the exposure area of ​​the writing field. When the wafer is moved to the wafer workbench through horizontal, vertical or combined movement to move the writing field (e.g., writing field No. 1) from the exposure area of ​​the writing field, the actual coordinates of the moved wafer in the writing field portion are newly recognized and recorded in the nano-contact sensor. A computer system in the lithography system performs a comparison process with the errors caused by the workbench movement and electron beam drift to calculate error calibration parameters for the exposure area of ​​the next writing field (e.g., writing field No. 2), and the wafer portion in the next writing field (writing field No. 2) is exposed to this writing field using the electron beam with the exposure coordinates calibrated. In this way, writing field No. 2 applies an additional offset calibrated to the electron beam to the writing field (writing field No. 1) previously removed from the exposure area to perform precise anastomosis splicing. After writing field No. 2 is exposed, the wafer workbench is moved to remove wafer writing field No. 2 from the exposure area of ​​the writing field.By repeatedly moving the wafer and performing horizontal and / or vertical error calibration on the wafer portion of each writing field exposed each time, closed-loop controlled splicing is achieved, and writing field splicing achieves splicing with sub-nanometer scale precision, without forcing further improvement in the electromechanical processing precision of the lithography system workbench. By adding the closed-loop splicing control technology called "Mingyanren" consisting of the nano-contact sensor detection technology and in-situ alignment coordinate mark detection technology of the present invention to current ordinary, low-cost lithography systems, high-precision photolithography splicing of sub-nanometer wafers can be achieved, and the lithography system of the present invention is low-cost and represents an innovative improvement over conventional technology.

[0114] The present invention will now be further described in conjunction with the figures and examples. Needless to say, these examples are merely schematic illustrations and are intended to explain the claims, and should not be construed as limiting the claims to these examples. [Brief explanation of the drawings]

[0115] [Figure 1a.1b] Electron beam photolithography principle diagram, where 1 - wafer (backing), 2 - photosensitive adhesive layer, 3 - graphics generated after exposure to electron beam (taking optical lattice as an example), 4 - electron beam emitted by electron gun in electron microscope tube, 5 - coordinate of electron beam at the position just exposed (CPJE), 6 - coordinate of electron beam at the position not exposed but targeted for exposure [Figure 2a.2b]Two diagrams showing the principle of the present invention, in which electron beams are used to induce photosensitive adhesive layer changes (EBIC), causing swelling and shrinkage on the sub-nanometer or nanometer scale to form uneven structures. 1 - wafer (backing), 2 - photosensitive adhesive layer, 7 - photosensitive adhesive layer not exposed to electron beam, 8 - EBIC of photosensitive adhesive layer exposed to electron beam (concave shrinkage occurs), 10 - EBIC of photosensitive adhesive layer exposed to electron beam (convex swelling occurs), 9 and 11 are the scales of concave shrinkage and convex swelling in the height direction, respectively, which are typically on the sub-nanometer to several nm scale. [Figure 3] Image of three alignment mark positions: 1 - wafer, 12 - remote out-of-field mark (RA1), 13 - in-field mark (IA), 14 - out-of-field mark between writing fields (RA2), 15 - writing field, 16 - rotation angle, X, Y - Cartesian coordinate system. The wafer is moved in the XYZ directions or in the XY, YZ, and XZ planes by the workbench. In conventional technology, both the mark 12 remote from the writing field and the mark 14 between writing fields are outside the writing field, making them remote alignment marks (RA marks) and only irradiated by the electron beam when the workbench is moved far from the writing field. The in-field mark (IA mark) adopted in this invention can be irradiated in the writing field without moving the wafer workbench. If the in-field mark is precisely placed on the photosensitive adhesive layer / wafer below the electron beam mark (CPJE, CPTE) or is moved very close to it, it can be used as an in-situ alignment mark (ISA). If two of these coordinates overlap, this in-situ alignment mark constitutes an coincident alignment mark (OA mark). [Figure 4]Another principle diagram of how the uneven structure is generated in the present invention. Wherein, 1—wafer, 2—photosensitive adhesive layer, 392—contact point of nano-contact sensor 39, 18—3D raised alignment mark (HAMR) on photosensitive adhesive layer, 19—3D raised alignment mark (HAMW) preset on the surface of the wafer, 20—height of the 3D raised mark preset on the surface of the wafer, located below photosensitive adhesive layer 2, 21—height of the 3D raised mark on photosensitive adhesive layer 2, the 3D raised mark on the photosensitive adhesive layer due to the transfer of the 3D raised mark preset on the surface of wafer 1, and the wave of this shape can be detected at contact point 392 of this uneven structure nano-contact sensor 39. [Figures 5a-5c] A process diagram illustrating the large splicing error between the previous and next writing fields in the prior art, where the writing field is a horizontal splice. In Figure 5a, 22 is writing field No. 1, the wafer in the writing field is in the exposure position, 23 is an optical grating (an example of an optical grating used as an exposure graphic), and 24 is an alignment mark far from the writing field. The figure shows writing field No. 1 (22) entering the exposure area for the first time and being exposed to the electron beam. In Figure 5b, 22' is writing field No. 1 moved from the exposure area, marked 22', 22 is the position of writing field No. 2, which is subsequently moved to the exposure area, 27 is the actual movement direction of the work bench 38, and 28 is the planned movement direction of the work bench 38. As the work bench 38 moves, writing field No. 1 is moved out of the writing field area where the electron beam can radiate, opening up space for the next writing field (i.e., writing field No. 2). Mechanical errors in the movement of the work bench 38 lead to splicing errors. In Fig. 5c, 29X is the horizontal (X direction) splicing error due to the workbench 38 movement, and 29Y is the vertical (Y direction) splicing error due to the workbench 38 movement. [Figure 6a] In the prior art, the wafer is exposed in the writing field No. 1 (22) of the exposure area and then the image is not transferred in situ. [Figure 6b]Image of a wafer being placed in write field No. 1 (22) in the exposure area, then moved for further processing, and then placed in a new exposure area on the workbench for photolithography or a second exposure. Errors due to workbench movement cause an offset in the new position 22' of write field No. 1, but in this case the write field in the electron beam exposure area is write field No. 2, i.e., the original write field position 22. Because write field 22' and write field No. 2 do not coincide, a vertical alignment error occurs. [Figure 7a-7b] Image of electron beam explained and expressed by electron beam induced photosensitive adhesive layer 2 change (EBIC). In Figure 7a, 1 - wafer, 2 - photosensitive adhesive layer 2, 17 - electron beam, 29 - focus of electron beam appearing at the exposed point of photosensitive adhesive layer 2. In Figure 7b, 1 - wafer, 2 - photosensitive adhesive layer 2, 17 - electron beam, 17' - position of electron beam drifted over time, 30 - drifted focus of electron beam irradiation appearing at the exposed point of photosensitive adhesive layer 2. [Figure 8] Schematic diagram of the sub-nanometer scale, high-precision writing field splicing lithography system of the present invention. [Figure 9a.9b.9c.9d.9e.9f] An illustration of the splicing alignment method using horizontal splicing as an example. [Figure 9a] After the wafer in writing field No. 1 (22-1) has been exposed but not yet moved from the exposure area, the nano-contact sensor measures the six position coordinates (for example) C1L1, C1L2, C1L3, C1R1, C1R2, and C1R3 of the in-situ alignment coordinate marks, where C1 represents writing field No. 1, Lx represents the left coordinate of the writing field, and Rx represents the right coordinate of the writing field. [Figure 9b]After the wafer in writing field No. 1 (22-1) is exposed, it moves from the exposure area 22 to writing field 22-1'. The nano-contact sensor measures the coordinates of the in-situ alignment marks, C1L1'-L3' and C1R1'-R3'. The next writing field moved to the exposure area 22 is writing field No. 2 (writing field 22-2), and the electron beam scan exposure area is 22-1, i.e., the current writing field 22-2. The wafer work bench moves, and writing field No. 2 is now at this position. However, it cannot be exposed due to a splicing error, and its coordinates are C2L1-L3 and C2R1-R3. After the work bench moves, the graphics related to writing field 22-1' are moved to the left of the next exposed writing field No. 2, and the coordinates measured by the corresponding nano-contact sensor are C1L1'-L3' and C1R1'-R3'. [Figure 9c] The actual coordinate values ​​of writing field No. 1 (22-1) after exposure and removal from the exposure area, which has become writing field 22-1', are compared with the coordinate values ​​of writing field No. 1 (22-1) after exposure and removal from the exposure area, and then adjusted using negative feedback of the error calibration values ​​obtained. This is an image of the position of the calibrated writing field of the actual exposed area, which has become calibrated writing field No. 2 (22-2'). The coordinates of calibrated writing field No. 2 (22-2') are C2L1', C2L2', C2L3' and C2R1', C2R2', C2R3', and C2L1' is equal to C1R1', C2L2' is equal to C1R2', and C2L3' is equal to C1R3'. In other words, calibrated writing field No. 2 (22-2') has achieved precise alignment with writing field 22-1'. [Figure 9d]The workbench has moved a first time, and writing field No. 2 has achieved seamless splicing with writing field No. 1. In this case, the workbench has moved a second time, opening a new exposure area space 22-3'. In this case, the coordinates of writing field No. 1 have become C1Lx', C1Rx' due to the second movement of the workbench, but the coordinates of writing field No. 2 have also become C2Lx', C2Rx' due to the second movement of the workbench. The corresponding coordinates for 22-3' are C3Lx', C3Rx'. The electron beam exposure area remains at 22-2'. [Figure 9e] The electron beam acquires the coordinate offset value of the exposure writing field No. 3, and the coordinate compensation of the electron beam moves the exposure area closer to the writing field 22-2''. Next, exposure of the writing field No. 3 is performed. [Figure 9f] The workbench is moved a third time, with 22-1´´ being moved accordingly to become 22-1´´´, 22-2´´ being moved accordingly to become 22-2´´´, and 22-3´´ being moved accordingly to become 22-3´´´, opening up exposed space 22-4´´ (located at 22-3´´). [Figure 10a.10b] 10a, the nano-contact sensor 39 has two sets of contact points 392, each installed on either side of the writing field 22, to facilitate the wafer being moved left or right for splicing. In this case, the two sets of contact points 392 expose the writing field 22 but have not moved out of the exposed area, and measure the in-situ alignment coordinate marks C1L1, C1L2, C1L3 and C1R1, C1R2, C1R3 preset in the writing field 22. For example, each set of nano-contact sensors 39 includes three vertically oriented contact points 392. [Figure 10b]Two sets of nano-contact sensors move to both sides of the writing field 22-1', expose, and then move out of the exposure area to measure the in-situ alignment coordinate marks C1L1', C1L2', C1L3' and C1R1', C1R2', C1R3' on the wafer at the position of the writing field 22-1', calculate the error calibration value of the wafer in the next entered writing field 22-2, adjust the exposure deflection parameters and focus of the electron gun in the electron microscope tube, and ensure that the calibrated splicing coordinates of the writing field 22-2' are accurately aligned with the writing field 22-1'. Process image [Figure 11] An image of a method for achieving vertical layer alignment splicing using a wafer, a preset 3D protruding structure 43 on a photosensitive adhesive layer, and a 3D structure 44 on the photosensitive adhesive layer as a 3D in-situ alignment coordinate mark, and an image of a method for achieving vertical layer alignment splicing by measuring the exposure offset error with an electron beam 4. A protruding wafer 3D alignment mark 43 is placed on a wafer to be photolithographically processed, and a photosensitive adhesive layer is applied thereto, resulting in a 3D alignment mark 44 on the photosensitive adhesive layer with a protruding structure corresponding to the position of the 3D alignment mark. The wafer with the 3D alignment mark is moved by a wafer workbench 38 to a writing field area where the electron beam can expose it, and the electron beam is aimed at the 3D alignment mark 44 (position 1) on the alignment photosensitive adhesive layer to perform point exposure, resulting in a 3D mark 45 (position 2) that may have an offset at the exposure point of the photosensitive adhesive layer. The nano-contact sensor measures positions 1 and 2 to calculate the exposure area calibration value of the writing field, and controls the electron gun to achieve precise alignment and exposure in the vertical direction, thereby achieving precise splicing. [Figure 12] Each nano-contact sensor has multiple nano-contact points. This shows how nano-contact sensors can be used to achieve fast splicing alignment. Nano-contact sensor 39 has two rows of guide arms, each with four nano-contact points. DETAILED DESCRIPTION OF THE INVENTION

[0116] 1 and 8, a sub-nanometer scale, high-precision writing field splicing lithography system is constructed, including an electron microscope body 31 sealed and stationary, a mesa 37 on the body 31, an electron microscope tube 32, at least one nano-contact sensor 39, and a wafer work bench 38. In the system, the electron microscope includes an electron beam tube 32, an electron projecting gun 372, a focus system 33, and a deflection coil 35, which are pulled onto the wafer work bench 38 for forward and backward and / or left and right and / or up and down movement and angle change. Computer Numerical Control There is a drive device 371 . [Example]

[0117] The control computer 42 is connected to the electron microscope tube and nano-contact sensor 39 via the electron beam control system 34 and the graphic generator 46, and transmits an in-situ alignment coordinate mark signal 40 and / or an electron beam drift signal 40 collected by the nano-contact sensor 39 to the graphic generator 46 under the control of the control computer 42. The graphic generator 46 transmits a processed and calibrated electron beam scan control signal to the electron beam control system 34 under the control of the control computer 42, and the electron beam control system 34 controls the shutter of the focus system 33 of the electron beam tube 32 and the deflection coil 35 for controlling the deflection of the electron beam. The configurations and operating principles of the electron microscope and nano-contact sensor are well known, so further description of the electron microscope and nano-contact sensor will not be provided here.

[0118] The electron beam tube 32 may also be equipped with a secondary electron imaging signal acquisition device 36 for feeding back secondary images scanned by the electron beam collected by the electron beam control system 34 to a control computer 42 for video display.

[0119] Nano-contact sensors39 have sub-nanometer scale measurement accuracy and can detect atoms. between force microscope The nano-contact sensor 39 may be one or more of a needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor. The nano-contact sensor 39 is mounted in the sample cavity of the electron beam lithography system and can measure the 3D shape of the surface with sub-nanometer scale accuracy and excellent spatial repeatability. The nano-contact sensor is located next to the electron beam tube 32, near the electron beam focus, and above the surface of the photosensitive adhesive layer.

[0120] The nano-contact sensor 39 has a lever-type sensor arm 391, and the touch arm 391 has a needle tip guide contactor 392 (see FIG. 8).

[0121] Each touch arm 391 has at least one row of tip guide contactors 392, and each row has one or more tip guide contactors 392.

[0122] 10, there are two rows of needle tip guide contactors 392, each row having one needle tip guide contactor 392, and the two rows are located on both sides of the electron beam tube 372, respectively.

[0123] Taking FIG. 12 as an example, there are two rows of the needle tip guide contactors 392, and each row has four needle tip guide contactors 392.

[0124] The electron beam tube 32 is aligned directly with the exposure area 22 of the wafer on the wafer workbench 38 .

[0125] Before carrying out the method of the present invention, wafer pre-processing is required. That is, a photosensitive adhesive layer 2 is coated on the wafer 1 and exposed to an electron beam. The wafer 1 and / or the photosensitive adhesive layer 2 have a writing field therein that can be expressed by being exposed to an electron beam and has a predetermined shape consisting of a concave and / or convex shape, and the nano-contact sensor 39 recognizes the in-situ alignment coordinate mark 8, in-situ alignment coordinate mark 10, in-situ alignment coordinate mark 44, or in-situ alignment coordinate mark 45.

[0126] The in-situ alignment coordinate marks may be planar graphic marks, and may be provided in one, two, three, four, five, six, or more positions on one plane, and of course, may be more. In this example, the planar graphic marks are preferably graphic marks created by minute geometric structure changes induced on the photoresist surface by an electron beam, but planar graphic marks with similar effects according to other known techniques may also be used, but this will not be discussed further here.

[0127] The in-situ alignment coordinate marks may be three-dimensional marks, and may be one, two, three, four, five, six, or more marks on one plane, and of course, may be even more. The three-dimensional marks are preferably pyramidal or conical in shape, which is convenient for electronic recognition, but may also be other shapes.

[0128] After constructing the above working environment, the sub-nanometer scale, high-precision lithography writing field splicing method of the present invention can be implemented, including the following steps.

[0129] Step 1: Install at least one of the mesa 37, the electron microscope and its tube 32, the electron gun 372, the wafer moving work bench 38, and the nano-contact sensor 39 in the main body 31 of the lithography system, and install a sensor for controlling the movement of the wafer work bench 38. Computer Numerical ControlA drive unit 371 is installed, and a photosensitive adhesive layer 2 is applied to the entire wafer 1 before the wafer is placed in the lithography system. The exposure area 22, which is the area scanned by the electron beam, is divided into several writing fields. Each writing field on the photosensitive adhesive layer has in-situ alignment coordinate marks 8, 10, 18, 43, and 44, which appear as predetermined shapes when exposed in a specific exposure area. The writing fields are sequentially numbered as writing field No. 1 (22-1), writing field No. 2 (22-2), ..., writing field No. n (22-n). For example, if there are 1,000 writing fields, n is 1,000, and exposure, movement, and splicing are required for 1,000 wafers in the writing fields.

[0130] Step 2: Place the wafer 1 coated with the photosensitive adhesive layer 2 on the workbench 38, and ensure that the wafer's writing field No. 1 (22-1) falls into the exposure area 22. Align the electron beam tube 32 of the electron microscope vertically with the exposure area 22, and then focus the electron beam on this writing field. Writing field No. 1 (22-1) refers to writing field No. 1, writing field No. 2 (22-2) refers to writing field No. 2, and writing field No. 3 (22-3) refers to writing field No. 3. The "" in "22-1" means that the workbench has moved once, and the "" in "22-1" means that the workbench has moved twice. That is, "22-1" refers to writing field No. 1, and means that the workbench has moved writing field No. 1 twice. The same analogy applies to the others.

[0131] Step 3: After exposing a portion of the wafer in writing field No. 1 (22-1) in the exposure area 22, a chemical reaction occurs in the photosensitive adhesive applied to this portion of the wafer, causing changes due to the electron beam to produce at least one or one group of relief structures that constitute the graphics. The specific shape of this relief structure is the characteristic shape of the pre-installed in-situ alignment coordinate mark, and the coordinate values ​​of its characteristic points in the exposure area are used as in-situ alignment coordinates.

[0132] Step 4: Start the nano-contact sensor (39) to measure the surface shape of the uneven structure, and then match it with the preset shape to recognize the alignment coordinate marks, and determine the coordinate values ​​(e.g., C1L1, C1L2, C1L3, C1R1, C1R2, C1R3) to be stored on the surface of the work bench. In principle, these coordinate points can be arbitrarily selected as one or more in the writing field (the same applies below).

[0133] Step 5: Pre-exposure preparation of writing field No. 2. The moving workbench 38 moves the moving wafer 1 horizontally and / or vertically to move the just-exposed writing field No. 1 area 22-1 out of the writing field 22-1' that is the exposure area, making space for the writing field No. 2 (22-2) of the next wafer to enter the exposure area.

[0134] Step 6: Start the nano contact sensor 39 to recognize the alignment coordinate mark in writing field No. 1 (22-1') moved from the above exposure area, and after it moves, determine and store the position coordinates (C1L1', C1L2', C1L3', C1R1', C1R2', C1R3') of writing field No. 1 on the surface of the work bench.

[0135] Step 7: Using the data of the alignment coordinate mark in the moved writing field No. 1 (22-1') as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the writing field movement, and determine the coordinate calibration value for the entire next exposure area of ​​the electron beam.

[0136] The coordinates of the error-calibrated writing field No. 2 (22-2') that is exposed adjacent to the writing field No. 1 (22-1') moved from the exposure area are C1R1', that is, the coordinate X C1R1´ , Y C1R1´ This is also the new coordinate for seamless splicing of the exposed writing field No. 2 (22-2') to the moved writing field No. 1 (22-1)'. That is, (X C2L1´ , Y C2L1´ ):X C2L1´ =X C1R1´ , Y C2L1´ =Y C1R1´

[0137] At this time, the coordinate of the electron beam hitting the writing field No. 2 (22-2) up to the error calibration in the exposure area 22 is C2L1, that is, the coordinate (X C2L1 , Y C2L1 ) This coordinate point is closely attached to the edge coordinate C1R1' of the writing field No. 1 (22-1') that is moving by applying a deflection voltage to the electron beam, and splicing calibration and exposure are performed for the coordinate of the writing field No. 2 (22-2). Therefore, the related coordinate point of the calibrated writing field No. 2 must be C2L1', and the coordinate difference between C2L1' and C2L1 must be as follows. ΔX1=X C2L1´ -X C2L1 =X C1R1´ -X C2L1 ΔY1=Y C2L1´ -Y C2L1 =Y C1R1´ -Y C2L1

[0138] Write field No. 2 and its coordinate X C2L1 , Y C2L1 Since this cannot be obtained when the work bench is not moving and not exposed, the entire electron beam drift that the electron beam exposes writing field No. 1 and exposed writing field No. 2 in the exposure area is ignored, and the coordinates of writing field No. 2 (22-2) in the exposure area until calibration are the X coordinates of the writing field No. 1 (22-1) in the exposure area. C2L1 =X C1L1 , Y C2L1 =Y C1L1 and this coordinate is detected by the uneven structure caused by exposure of the surface of the photosensitive adhesive layer after the exposure of writing field No. 1 and before the movement of the work bench, to obtain the coordinate difference that needs to be compensated for in the calibration of all the electron beam coordinate points of writing field No. 2. ΔX1=X C1R1´ -X C1L1 ΔY1=Y C1R1´ -Y C1L1

[0139] Step 8: Adjust the deflection voltage of the electron beam tube 32 according to the coordinate difference (ΔX1, ΔY1) that needs to be compensated for after the calibration, calibrate the exposure area of ​​the electron beam, and then calibrate the splicing coordinates (C2L1, C2L2, C2L3, C2R1, C2R2, C2R3) of the writing field No. 2 (22-2) of the wafer entering the exposure area to the adjacent splicing coordinates (C2L1', C2L2', C2L3', C2R1', C2R2', C2R3') of the shifted writing field No. 1, so that the splicing coordinates of the calibrated writing field No. 2 (22-2') achieve seamless splicing with the shifted writing field No. 1.

[0140] Step 9: Electron beam exposure is performed on the wafer portion of writing field No. 2 (22-2') that has been moved to the calibrated exposure area of ​​the electron beam exposure coordinates, causing a chemical reaction in the photosensitive adhesive applied to the exposed portion of the wafer to reveal alignment coordinate marks in this writing field that feature the preset relief structure.

[0141] Step 10: Start the nano-contact sensor 39 to recognize the alignment coordinate mark against the preset shape, and determine and store the position coordinates (C2L1', C2L2', C2L3', C2R1', C2R2', C2R3') of the feature coordinate points in the calibrated writing field No. 2 (22-2') on the surface of the workbench.

[0142] Step 11: Prepare writing field No. 3 before exposure, and move the work bench 38 again to move the wafer 1 moving horizontally and / or vertically to move the previously moved writing field No. 1 (22-1') and the just-exposed calibrated writing field No. 2 (22-2'), so that the just-exposed calibrated writing field No. 2 is removed from the exposure area. Due to the movement of the work bench, the position coordinates of the previously moved writing field No. 1 (22-1') change and it becomes the twice moved writing field No. 1 (22-1'), with its position coordinates changing from (C1Lx', C1Rx') to (C1Lx''', C1Rx''). The position coordinates of the calibrated and then moved writing field No. 2 from the exposure area change from (C2Lx', C2Rx') to (C2Lx''', C2Rx''. This writing field No. 2 becomes the moved writing field No. 2 (22-2'), making space for the writing field No. 3 (22-3') of the next wafer to be moved to the exposure area.

[0143] Step 12: Start the nano contact sensor 39 again to recognize the alignment coordinate mark in writing field No. 2 (22-2'') moved from the above exposure area, and determine and store its position coordinates (C2L1'', C2L2'', C2L3'', C2R1'', C2R2'', C2R3'') on the surface of the work bench 38.

[0144] Step 13: Using the data of the alignment coordinate mark in the moved writing field No. 2 as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the movement, and determine the calibration values ​​Δ×2 and ΔY2 of the writing field in the next exposure area of ​​the electron beam.

[0145] The coordinates of the writing field No. 3, which is adjacent to the writing field No. 2 moved from the exposure area, are C2R1', that is, the coordinates (X C2R1´´、 Y C2R1´´ ) is the calibration coordinate for seamless splicing of the exposed writing field No. 3 to the shifted writing field No. 2, i.e., (X C3L1´´、 Y C3L1´´ ):X C3L1´´ =X C2R1´´、 Y C3L1´´ =Y C2 R1´´ It is also.

[0146] At this time, the coordinate of the electron beam for writing field No. 3 in the exposed area is C3L1, i.e., the coordinate (X C3L1 , Y C3L1 ), the coordinate difference with the moving writing field No. 2 exposed according to splicing is this coordinate point, and the splicing exposure is performed by closely adhering to the edge C2 R1'' of the moving writing field No. 2 (22-2'') by the electron beam additional deflection voltage, and the related coordinate point of the calibrated writing field No. 3 (22-3'') is C3 L1'', and the coordinate difference between C3 L1'' and C3 L1'' is as follows. Δ×2 =X C3L1´´ -X C3L1´ =XC2R1´´ -X C3L1´ ΔY2=Y C3L1´´ -Y C3L1´ =Y C2R1´´ -Y C3L1´

[0147] Expose writing field No. 2 and writing field No. 3 in the exposure area. Ignore the entire electron beam drift in the exposure area, and write field No. 3 is the coordinate until the exposure coordinate of the exposure area is calibrated. Coordinate X in the case of exposure of writing field No. 2. C3L1´ =X C2L1´ , Y C3L1´ =Y C2L1´ and this coordinate is detected by the uneven structure caused by exposure of the surface of the photosensitive adhesive layer from the time when writing field No. 2 is exposed until the work bench is moved, thereby obtaining the coordinate difference that needs to be compensated for in the coordinate calibration of all electron beams at the writing field exposure points. Δ×2 =X C2R1´´ -X C2L1´ ΔY2=Y C2R1´´ -Y C2L1´

[0148] Step 14: Adjust the deflection voltage of the electron beam tube 32 according to the obtained calibration value, and calibrate the exposure area of ​​the electron beam so that the coordinates of all exposure points of the writing field No. 3 on the wafer are consistent with the splicing coordinates of the moved writing field No. 2 and the adjacent writing field No. 3 to achieve seamless splicing.

[0149] Step 15: Repeat to complete the entire exposure, transfer and splicing of the entire writing field area of ​​the wafer.

[0150] In this example

[0151] The electron beam may be any of an ion beam, a photon beam, and an atomic beam.

[0152] Nano contact sensor 39 is an atomic between force microscope The sensor may be a needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor, or a combination of these.

[0153] The in-situ alignment coordinate marks 8, 10, and 18 may be planar graphic marks, each of which may have one, two, three, four, five, or six marks on one plane, or may have more marks according to actual needs. Here, the so-called planar graphic marks are broad in meaning and particularly include graphic marks resulting from minute geometric structure changes caused by the electron beam irradiating the photoresist surface.

[0154] In this example, an electron beam induces a photoresist surface to produce a graphics mark by varying the minute geometric structure, resulting in a flat graphics mark.

[0155] The in-situ alignment coordinate marks 43 and 44 may be three-dimensional marks, preferably pyramidal or conical in shape, and may be one, two, three, four, five, six, or more marks on a single plane.

[0156] In this example, there are preferably 1 to 4 nano-contact sensors 39 around the exposed area.

[0157] The nano-touch sensor 39 has a lever-type sensor arm 391 with one or more stylus-tip guide contactors 392 aligned in a row on the touch arm 391 .

[0158] The electron beam may be a Gaussian beam or a modified beam.

[0159] 7a and 7b, the method for measuring the electron beam drift includes the following steps: A mesa 37, an electron microscope tube 32 and its electron gun 372, a wafer moving work bench 38, and a nano-contact sensor 39 are installed in the main body 31 of the lithography system, and the wafer work bench 38 is provided with a sensor for controlling its movement. Computer Numerical Control A drive device 371 is installed, a photosensitive adhesive layer is coated on the wafer, and then an electron gun 372 emits an electron beam 17, focuses it on the photosensitive adhesive layer, and exposes it. The exposure causes a slight change in the geometric shape of the uneven structure induced by the electron beam on the surface of the photosensitive adhesive layer. This slight change is detected, the focus drift is traced over time, and the coordinate values ​​and drift amount of the electron beam drift trajectory 30 over time are recorded. The recorded coordinate values ​​and drift amount of the electron beam drift trajectory 30 over time are used to calculate the electron beam exposure coordinate values ​​and calibration compensation difference values ​​over time from the start to the end, and the calibration coordinates for the next writing field exposure are determined.

[0160] As shown in FIG. 8, the nano-contact sensor 39 has a lever-type sensor arm 391 and one or more needle tip guide contactors 392 aligned in a row on the touch arm 391 .

[0161] As shown in Figure 11, the sub-nanometer scale, high-precision photolithography writing field vertical directionIn the splicing method, a wafer 3D alignment mark 43 with a protruding structure is formed on the wafer to be photolithographically processed, and a photosensitive adhesive layer 2 is applied thereto, so that a 3D alignment mark 44 with a corresponding protruding structure is generated on the photosensitive adhesive layer at the position where the 3D alignment mark is located. Then, the wafer 1 with the 3D alignment mark is moved to the writing field area where the electron beam 4 can be exposed using the wafer workbench 38, and the electron beam 4 is aimed at the position of the 3D alignment mark 44 on the alignment photosensitive adhesive layer to perform point exposure, so that an actual offset 3D mark 45 is generated at a location other than the exposure point on the photosensitive adhesive layer, and the actual coordinate values ​​of the 3D alignment mark 44 and the offset 3D mark 45 are measured using the photosensitive adhesive layer of the nano-contact sensor, and the calibration value of the exposure area of ​​the writing field is calculated. vertical direction controlling the electron gun to achieve precise alignment and exposure of vertical direction Achieve precise splicing.

[0162] FIG. 12 shows a schematic diagram of a nano-contact sensor 39 having multiple nano-contact points 392 on each nano-contact sensor 39 for achieving rapid splicing alignment.

Claims

1. A method for splicing a sub-nanometer scale, high precision lithographic writing field, comprising the steps of: Step 1: Install the mesa (37), the electron microscope tube (32) and its electron gun (372), the movable wafer workbench (38) and at least one nano-contact sensor (39) in the main body of the lithography system (31), and the computer numerical control drive device (371) for controlling the movement of the wafer workbench (38). Before the wafer is placed in the lithography system, the photosensitive adhesive layer (2) is applied to the entire wafer (1), and the area scanned by the electron beam is the exposure area (22). The exposure area is divided into several writing fields, and each writing field in the photosensitive adhesive layer has an in-situ alignment coordinate mark (8, 10, 18, 43, 44) that appears in a predetermined shape when exposed in a certain exposure area, and the writing fields are successively written field No. 1 (22-1), written field No. 2 (22-2), ..., written field No. n (22-n). Step 2: Place the wafer (1) coated with the photosensitive adhesive layer (2) on the workbench (38) so that the writing field No. 1 (22-1) of the wafer falls into the exposure area (22), and orient the electron beam tube (32) of the electron microscope vertically toward the exposure area (22) and then focus the electron beam on the writing field; Step 3: After exposing the part of the wafer in the writing field No. 1 (22-1) in the exposure area, a chemical reaction occurs in the photosensitive adhesive applied to this part of the wafer, which causes a change caused by the electron beam to produce at least one or a group of relief structures constituting the graphics. The determined shape of this relief structure is the characteristic shape of the pre-installed in-situ alignment coordinate mark, and the coordinate values ​​of its characteristic points in the exposure area are made into the in-situ alignment coordinates. Step 4: Start the nano-contact sensor (39) to measure the surface shape of the uneven structure, and then recognize the alignment coordinate marks according to the preset shape, and determine and store the coordinate values ​​(C1L1, C1L2, C1L3, C1R1, C1R2, C1R3) on the surface of the workbench; Step 5: preparing the writing field No. 2 for exposure, the moving workbench (38) moves the moving wafer (1) in a horizontal and / or vertical orientation so that the just exposed writing field No. 1 area (22-1) leaves the exposure area and becomes the writing field 22-1', making room for the writing field No. 2 (22-2) of the next wafer entering the exposure area; Step 6: Start the nano-contact sensor (39) to recognize the alignment coordinate mark in the writing field No. 1 (22-1') moved from the above-mentioned exposed area, and determine and store the position coordinate (C1L1', C1L2', C1L3', C1R1', C1R2', C1R3') of the writing field No. 1 on the surface of the workbench after it moves; Step 7: Using the data of the alignment coordinate mark in the moved writing field No. 1 (22-1') as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the writing field movement, and determine the coordinate calibration value of the entire next exposure area of ​​the electron beam; The coordinates of the error-calibrated writing field No. 2 (22-2') that is adjacent to the writing field No. 1 (22-1') moved from the exposure area are C 1R1´ , i.e., coordinates (XC 1R1´ , Y.C. 1R1´ ) which is also the new coordinate that must be seamlessly spliced ​​into the moved writing field No. 1 (22-1') of the writing field No. 2 (22-2') in the exposed area, i.e. (X) C2L1´ ,AND C2L1´ ):X C2L1´ =X C1R1´ ,AND C2L1´ =And C1R1´ At this time, the electron beam is adjusted to the coordinates C2L1, i.e., the coordinates (X C2L1 , Y C2L1 ) This coordinate point is closely attached to the edge coordinate C1R1' of the moving writing field No. 1 (22-1') by applying a deflection voltage to the electron beam, and splicing calibration and exposure are performed for the coordinate of the writing field No. 2 (22-2), and the related coordinate point of the calibrated writing field No. 2 is C 2L1´ , C 2L1´ and C. 2L1 The coordinate difference between the two must be as follows: ΔX 1 =X C2L1´ -X C2L1 =X C1R1´ -X C2L1 ΔY 1 =Y C2L1´ -Y C2L1 =Y C1R1´ -Y C2L1 Since the writing field No. 2 and its coordinates (XC2L1, YC2L1) cannot be obtained when the workbench is not moving and not exposed, the entire electron beam drift in which the electron beam exposes the writing field No. 1 and the exposed writing field No. 2 in the exposed area is ignored, and the coordinates of the writing field No. 2 (22-2) in the exposed area until the exposure and calibration are the X coordinates of the writing field No. 1 (22-1) in the exposed area are the X coordinates of the writing field No. 1 (22-1) in the exposed area. C2L1 = X C1L1 , Y C2L1 = Y C1L1 This coordinate is detected by the uneven structure caused by the exposure of the surface of the photosensitive adhesive layer after the writing field No. 1 is exposed and before the workbench is moved, and the coordinate difference that needs to be compensated for is obtained for all the calibration of the electron beam coordinate points of the writing field No.

2. ΔX 1 =X C1R1´ -X C1L1 ΔY 1 =Y C1R1´ -Y C1L1 Step 8: The coordinate difference (ΔX 1 , ΔY 1 ) to adjust the deflection voltage of the electron beam tube (32) to calibrate the exposure area of ​​the electron beam, so that the splicing coordinates (C2L1, C2L2, C2L3, C2R1, C2R2, C2R3;) of the writing field No. 2 (22-2) of the wafer entering the exposure area are calibrated to the splicing coordinates adjacent to the moved writing field No. 1, and the splicing coordinates of the calibrated writing field No. 2 (22-2') achieve seamless splicing with the moved writing field No.

1.

2. The method for splicing a sub-nanometer scale, high-precision lithography writing field according to claim 1, further comprising the steps of: Step 9: performing electron beam exposure on the wafer portion of writing field No. 2 (22-2') transferred to the calibrated exposure area of ​​the electron beam exposure coordinates, so that the photosensitive adhesive applied to the exposed portion of the wafer undergoes a chemical reaction to reveal the alignment coordinate marks in the writing field characterized by the preset determined relief structure; Step 10: Start the nano-contact sensor (39) to recognize the alignment coordinate mark according to the preset shape, and determine and store the position coordinates (C2L1', C2L2', C2L3', C2R1', C2R2', C2R3') of the feature coordinate points in the calibrated writing field No. 2 (22-2') on the surface of the workbench; Step 11: Pre-exposure preparation of writing field No. 3 is performed, and the moving workbench (38) moves the moving wafer (1) horizontally and / or vertically again, so that the previously moved writing field No. 1 (22-1') and the just-exposed calibrated writing field No. 2 (22-2') are moved, and the just-exposed calibrated writing field No. 2 is moved out of the exposure area. Due to the movement of the workbench, the position coordinates of the previously moved writing field No. 1 (22-1') change, and it becomes the twice-moved writing field No. 1 (22-1'), and its position coordinates change from (C1Lx', C1Rx') to (C1Lx', C1Rx'), and the position coordinates of the calibrated writing field No. 2 moved out of the exposure area after being calibrated change from (C2Lx', C2Rx') to (C2Lx', C2Rx'). This writing field No. 2 becomes the moved writing field No. 2 (22-2´´) and leaves a space for writing field No. 3 (22-3´) of the wafer that is then moved to the exposure area. Step 12: Start the nano contact sensor (39) again to recognize the alignment coordinate mark in the writing field No. 2 (22-2´´) moved from the above exposure area, and determine and store the position coordinates (C2L1´´, C2L2´´, C2L3´´, C2R1´´, C2R2´´, C2R3´´) on the surface of the workbench (38); Step 13: Using the data of the alignment coordinate mark in the moved writing field No. 2 as the basis for closed-loop feedback control, calculate the actual coordinate offset before and after the movement, and set the calibration values ​​Δ×2 and ΔY of the writing field of the next exposure area of ​​the electron beam. 2 Confirm the The coordinates of the writing field No. 3, which is adjacent to the writing field No. 2 that has been moved from the exposure area, are C2R1'', that is, the coordinates (X C2R1´´ , Y C2R1´´ ) This is also the calibration coordinate for the exposed writing field No. 3 to be seamlessly spliced ​​to the moved writing field No. 2, i.e. (X) C3L1´´、 AND C3L1´´ ):X C3L1´´ =X C2R1´´、 AND C3L1´´ =And C2 R1´´ At this time, the electron beam is focused on the coordinates C3L1 for the writing field No. 3 in the exposed area, i.e., the coordinates (X C3L1 , Y C3L1 ), and the coordinate difference with the moving writing field No. 2 exposed according to splicing is this coordinate point. The splicing exposure is performed by closely adhering to the edge C2 R1 ´ ´ of the moving writing field No. 2 (22-2 ´ ´ ) by the electron beam additional deflection voltage, and the related coordinate point of the calibrated writing field No. 3 (22-3 ´ ´ ´ ) is C3 L1 ´ ´ , and the coordinate difference between C3 L1 ´ ... Δ×2 =X C3L1´´ -X C3L1´ =X C2R1´´ -X C3L1´ ΔY 2 =Y C3L1´´ -Y C3L1´ =Y C2R1´´ -Y C3L1 Expose writing field No. 2 and writing field No. 3 in the exposed area. Ignore the entire electron beam drift in the exposed area, and the coordinates of writing field No. 3 are calibrated until the exposure coordinates of the exposed area are calibrated. The coordinates of writing field No. 2 are exposed. C3L1´ = X C2L1´ , Y C3L1´ = Y C2L1´ and this coordinate is detected by the uneven structure caused by the exposure of the surface of the photosensitive adhesive layer from the time when the writing field No. 2 is exposed until the work bench is moved, thereby obtaining the coordinate difference that needs to be compensated for in the coordinate calibration of all the electron beams at the writing field exposure points; Δ×2 =X C2R1´´ -X C2L1´ ΔY 2 =Y C2R1´´ -Y C2L1´ Step 14: Adjust the deflection voltage of the electron beam tube (32) according to the obtained calibration value, and calibrate the exposure area of ​​the electron beam so that the coordinates of all the exposure points of the writing field No. 3 of the wafer are consistent with the splicing coordinates of the moved writing field No. 2 and the adjacent ones to achieve seamless splicing; Step 15: Repeat to complete the full exposure, transfer and splicing of the entire writing field area of ​​the wafer.

3. 2. The method for splicing a sub-nanometer scale, high precision lithography writing field according to claim 1, wherein the electron beam can be an ion beam, a photon beam, or an atomic beam.

4. 2. The method for splicing a sub-nanometer scale, high-precision lithography writing field as claimed in claim 1, wherein the nano-contact sensor (39) is one or a combination of an atomic force microscope needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor.

5. 2. The method of claim 1, wherein the wafer is a complete wafer, a portion of a wafer, or a wafer containing non-wafer material that is in need of processing by photolithographically written field splicing.

6. The method for splicing a sub-nanometer scale, high precision lithographic writing field according to claim 1, characterized in that the in-situ alignment coordinate marks (8, 10, 18) are graphics marks of planar configuration.

7. 7. The method for splicing a sub-nanometer scale, high precision lithography writing field as claimed in claim 6, wherein the planar configuration of graphic marks is one, two, three, four, five, six or more in one plane.

8. The sub-nanometer scale, high-precision lithography writing field splicing method of claim 6, characterized in that the planar graphic mark includes a graphic mark resulting from a change in a micro geometric structure caused by an electron beam inducing on a photoresist surface.

9. The method for splicing a sub-nanometer scale, high-precision lithography writing field as claimed in claim 1, characterized in that the in-situ alignment coordinate marks (43, 44) are three-dimensional marks.

10. 10. The method for splicing a sub-nanometer scale, high precision lithography writing field according to claim 9, wherein the three-dimensional mark is pyramidal or conical, and there are one, two, three, four, five, six or more of these marks in one plane.

11. The method for splicing a sub-nanometer scale, high precision lithographic writing field according to any one of claims 1 to 10, characterized in that the nano contact sensors (39) are one, two, three, four or more and are located around the exposed area.

12. The method for splicing a sub-nanometer scale, high precision lithography writing field as claimed in claim 11, characterized in that the nano-contact sensor (39) has a lever-type sensor arm (391) and a needle tip guided contactor (392) arranged in a row on the touch arm (391).

13. The method for splicing a sub-nanometer scale, high precision lithography writing field according to any one of claims 1 to 10, characterized in that the electron beam is a Gaussian beam.

14. The method for splicing a sub-nanometer scale, high precision lithographic writing field according to any one of claims 1 to 10, characterized in that the electron beam is a modified beam.

15. A sub-nanometer scale, high precision written field splicing lithography system including a stationary mounted apparatus (31) and a mesa (37) mounted on the apparatus, with an electron microscope, at least one nano contact sensor (39) and a moving wafer workbench (38) mounted on top of the mesa, an electron beam tube (32) mounted on the electron microscope, and a computer numerically controlled drive device (371) for pulling the wafer workbench (38) and moving it back and forth and / or left and right and / or up and down and changing the angle.

16. 16. The sub-nanometer scale, high precision writing field splicing lithography system according to claim 15, characterized in that the lithography system also includes a control computer (42) connected to a graphic generator (46), an electron beam control system (34) and a computer numerically controlled drive device (371) of the wafer workbench (38), wherein the control computer (42) controls the control of the graphic generator (46) to transmit the in-situ alignment coordinate mark signal (40) and / or the electron beam drift signal (40) on the detected wafer collected by the nano-contact sensor (39) to the graphic generator (46), and the control of the graphic generator (46) controls the control computer (42) to transmit the processed and calibrated electron beam scan and control signal to the electron beam control system (34), which controls the shutter of the focus system (32) of the electron beam tube (32) and the deflection coil (35) for controlling the deflection of the electron beam.

17. The sub-nanometer scale, high precision writing field splicing lithography system of claim 16, further comprising a secondary electron imaging signal acquisition device (36) for feeding back a secondary image scanned by the electron beam collected in the electron beam tube (32) to the control computer (42) through the electron beam control system (34).

18. 16. The sub-nanometer scale, high precision writing field splicing lithography system of claim 15, wherein the nano-contact sensor (39) is one or a combination of an atomic force microscope needle tip sensor, a tunneling electron probe sensor, or a nanoscale surface work function measurement sensor.

19. 16. The sub-nanometer scale, high-precision writing field splicing lithography system of claim 15, wherein the nano-contact sensor (39) comprises a lever-type sensor arm (391), and the touch arm (391) comprises a needle-tip guided contactor (392).

20. 20. The sub-nanometer scale, high precision writing field splicing lithography system of claim 19, wherein each touch arm (391) has one or more needle tip guided contactors (392).

21. 20. The sub-nanometer scale, high precision writing field splicing lithography system of claim 19, wherein each touch arm (391) has at least one row of tip-guided contactors, each row having one or more tip-guided contactors (392).

22. The sub-nanometer scale, high precision writing field splicing lithography system of any one of claims 15 to 21, characterized in that there are two rows of the nano contact sensors (39), four per row, with the two rows each on either side of the electron beam tube (32).

23. 23. The sub-nanometer scale, high precision writing field splicing lithography system of claim 22, wherein the electron beam tube (32) is directed toward an exposure area (22) of a wafer on the workbench (38).

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