Electron beam detection device
By using a spectrometer in the electron beam detection equipment to split the detection laser into multiple beams of split laser light, and combining it with an interferometer, the accuracy problem of full-stroke position measurement of the translation stage in the vacuum chamber is solved, and a high-precision and low-cost measurement solution is achieved.
Patent Information
- Application Number
- CN202423076661.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2034-12-12
AI Technical Summary
In electron beam detection equipment, it is difficult for the translation stage in the vacuum chamber to accurately measure the full-stroke position information in a certain direction. The existing solution adds a laser interferometer, which leads to data switching errors and affects the measurement accuracy and reliability.
A spectrometer is used to split the detection laser into multiple parallel and spaced split laser beams, which are emitted in a vertical direction. Combined with the first and second interferometers, the measurement and feedback of the full-stroke position information of the translation stage within the preset plane are ensured. The optical path is optimized through a spectrometer and a reflector to reduce costs.
The accurate position information measurement of the translation stage within the entire stroke is achieved, which improves the measurement accuracy and reliability, reduces the data switching error, and reduces the cost of beam splitting laser generation.
Smart Images
Figure CN223460993U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of semiconductor detection, in particular to a kind of electron beam detection equipment. BACKGROUND
[0002] CD-SEM (scanning electron microscope) and other electron beam detection equipment is important equipment of semiconductor manufacturing front process, and it has important significance to verify the rationality and reliability of front process parameter setting.In practical application, wafer is adsorbed on translation stage in vacuum chamber, and translation stage drives wafer to translate in preset plane to make wafer scan under electron gun at certain speed.Through collecting secondary electron generated by scanning wafer and converting image by signal, the line profile characteristics of wafer surface can be reflected, and the quality of lithography, etching and other processes can be judged.
[0003] The whole process, the information position of bad point and other defects, the next process of wafer, and the deficiency of previous process are reversed to improve process have key role.At present, defect position information is generally obtained by translation stage cooperating with laser interferometer, and laser interferometer measurement has the advantages of high precision, non-contact, real-time, multifunction and high stability.Specifically, a laser interferometer is arranged along the first detection direction of the preset plane and the second detection direction perpendicular to the first detection direction to obtain translation stage position information and then obtain defect position information.But for use in vacuum chamber, considering the size of motion platform, motion stroke and the size of vacuum chamber, it is difficult to meet the full-stroke position measurement information feedback in a certain direction.Generally, the solution is to increase a laser interferometer in this direction, but two laser interferometers exist in the same direction, which will cause data switching when measuring position information feedback, and switching will inevitably cause certain error, which brings precision risk to measurement and makes data reliability questionable. UTILITY MODEL CONTENTS
[0004] The utility model aims at meeting the full-stroke position information measurement feedback of translation stage in a detection direction in electron beam measurement device and ensuring the accuracy of measurement information as far as possible.
[0005] Particularly, the utility model provides a kind of electron beam detection equipment, it includes:
[0006] Electron beam imaging module is configured to project incident electron beam to the surface of sample to be measured and generates electron beam image;
[0007] Translation stage is used to place the sample to be measured, and is configured to drive the sample to be measured to translate in preset plane;
[0008] First interferometer is configured to emit detection laser along the first detection direction of the preset plane;
[0009] A beam splitting assembly is arranged in the path of the probe laser and configured to split the probe laser into a plurality of beams of split laser beams that are parallel and spaced apart and emitted along a second probe direction, and the second probe direction is perpendicular to the first probe direction in the preset plane.
[0010] Optionally, the translation stage is configured to translate in the preset plane along the first probe direction and the second probe direction.
[0011] Optionally, a moving range of the translation stage in the preset plane is configured as a rectangle, and the first probe direction and the second probe direction are parallel to two adjacent sides of the rectangle, respectively.
[0012] Optionally, the beam splitting assembly is arranged outside a side of the rectangle that is parallel to the first probe direction.
[0013] Optionally, the beam splitting assembly comprises:
[0014] at least one beam splitter arranged in the path of the probe laser, and each beam splitter forms one of the split laser beams by reflecting light from itself;
[0015] a mirror arranged at the end of the path of the probe laser and configured to reflect transmitted light from the at least one beam splitter along the second probe direction to form one of the split laser beams.
[0016] Optionally, the at least one beam splitter is one; and
[0017] The distance from the beam splitter to the mirror and to the first interferometer is equal.
[0018] Optionally, the at least one beam splitter is a plurality; and
[0019] The plurality of beam splitters are arranged at equal intervals.
[0020] Optionally, the electron beam detection device further comprises:
[0021] a second interferometer arranged outside a side of the rectangle that is parallel to the second probe direction and configured to emit laser light directly to the sample to be measured along the first probe direction.
[0022] Optionally, the translation stage is arranged in a vacuum chamber.
[0023] Optionally, the electron beam imaging module comprises an electron beam emitting source and an exit electron detector, wherein the electron beam emitting source is configured to generate and emit the incident electrons, and the exit electron detector is configured to receive at least one of secondary electrons and backscattered electrons generated by the incident electron beam projected to the sample to be measured and generate the electron beam image.
[0024] In the utility model, the first interferometer emits detection laser along the first detection direction of the preset plane, the light splitting assembly is arranged on the light path of the detection laser, the detection laser is split into multiple beams of parallel spaced beam splitting lasers emitted along the second detection direction, the second detection direction is perpendicular to the first detection direction in the preset plane, when the translation stage moves beyond the measurement range of one beam of beam splitting laser, i.e. enters the measurement range of other beam splitting lasers, the full stroke position information measurement feedback of the translation stage in the first detection direction is met, and the measurement accuracy is improved based on the beam splitting laser measurement.
[0025] Further, the utility model makes the translation stage translate along the first detection direction and the second detection direction in the preset plane, so that the motion position of the translation stage in the preset plane can be measured based on the beam splitting laser.
[0026] Still further, the utility model makes the light splitting assembly comprise at least one beam splitter and a mirror, the at least one beam splitter is arranged along the light path of the detection laser, and the mirror is arranged at the end of the light path of the detection laser, so that the generation cost of the beam splitting laser is reduced.
[0027] Still further, when the at least one beam splitter is one, the utility model makes the distance from the beam splitter to the mirror and to the first interferometer equal, so that when the translation stage moves beyond the measurement range of one beam of beam splitting laser, i.e. enters the measurement range of another beam of beam splitting laser, the full stroke position information measurement feedback of the translation stage in the first detection direction is met.
[0028] Still further, when the at least one beam splitter is multiple, the utility model makes the multiple beam splitters be arranged at equal intervals, so that when the translation stage moves beyond the measurement range of one beam of beam splitting laser, i.e. enters the measurement range of other beams of beam splitting laser in turn, the full stroke position information measurement feedback of the translation stage in the first detection direction is met.
[0029] Still further, the utility model makes the second interferometer be arranged outside the side of the rectangle parallel to the second detection direction, and emits laser directly to the sample to be measured along the first detection direction, so that the full stroke position information measurement feedback of the translation stage in the second detection direction is met.
[0030] Furthermore, the present invention can reduce the collision between the electron beam and the gas and improve the detection accuracy of the sample to be tested by arranging the translation stage in the vacuum chamber.
[0031] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below.
[0032] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:
[0034] Figure 1 is a schematic structural block diagram of an electron beam detection device according to an embodiment of the present utility model;
[0035] Figure 2 For about Figure 1 A schematic diagram of the intermediate translation stage, the first interferometer, and the beam splitting assembly;
[0036] Figure 3 For about Figure 1 Another schematic diagram of the middle translation stage, first interferometer, and beam splitting assembly.
[0037] Description of reference numerals:
[0038] 100. Electron beam testing equipment;
[0039] 110. Electron beam imaging module; 111. Electron beam emission source; 112. Emitted electron detector;
[0040] 120, translation stage;
[0041] 130. Preset plane; 131. Moving range;
[0042] 140. First interferometer;
[0043] 150, optical splitter assembly;
[0044] 151. Spectroscope;
[0045] 152. Reflector;
[0046] 160, second interferometer;
[0047] 170, probe laser emitted by the first interferometer;
[0048] 180, split laser;
[0049] 190, probe laser emitted by the second interferometer. DETAILED DESCRIPTION
[0050] The electron beam detection device according to the embodiments of the present application will be described below with reference to the accompanying drawings. In the description of the embodiments of the present application, the terms "upper", "lower", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Figures 1 to 3
[0051] The terms "first", "second", and the like are used only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include at least one of the features, i.e., one or more of the features. In the description of the present application, "one or more" means one or more, and "a plurality of" means at least two, such as two, three, and the like, unless otherwise specifically limited. In the description of the present application, when a certain feature "includes or contains" a certain or certain features, unless otherwise specifically described, it indicates that other features are not excluded and can further include other features.
[0052] In the description of the embodiments, the description of the terms "one embodiment", "some embodiments", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials, or characteristics can be combined in any one or more embodiments or examples in a suitable manner.
[0053] Unless otherwise defined, all terms (including technical and scientific terms) used in the description of the embodiments of the present application have the same meaning as commonly understood by those skilled in the art to which the present application belongs.
[0054] The electron beam detection apparatus mentioned below is widely used in the semiconductor industry. For example, the electron beam detection apparatus can be a scanning electron microscope, which is usually used for defect detection of production objects such as chips. The main principle of the scanning electron microscope is to use a charged particle beam to bombard the surface of the measured object, and to detect the secondary electron signal generated by the bombarded area to obtain various physical and chemical information of the measured sample itself, such as topography, composition, feature distribution, etc. Typical applications of the electron beam detection apparatus are usually in the detection and measurement of key dimensions of micro patterns on semiconductor silicon wafers and mask plates based on electron beams in a vacuum, detection of open defects and short circuit defects in CMOS integrated circuits.
[0055] Figure 1 is a schematic structural block diagram of an electron beam detection apparatus according to an embodiment of the present application; Figure 2 is about Figure 1 is a schematic diagram of a translation stage, a first interferometer and a light splitting assembly. Figure 3 is about Figure 1 is another schematic diagram of a translation stage, a first interferometer and a light splitting assembly. Figure 2 and Figure 3 The X-axis direction shown in FIG. 1 is the first detection direction in the following, and the Y-axis direction is the second detection direction in the following, Figure 2 The movement stroke of the translation stage shown in FIG. 1 in the first detection direction is less than Figure 3 The movement stroke of the translation stage shown in FIG. 1 in the first detection direction.
[0056] Referring to Figures 1-3As shown, the electron beam detection device 100 proposed by the utility model includes an electron beam imaging module 110, a translation stage 120, a first interferometer 140 and a light splitting assembly 150. Among them, the electron beam imaging module 110 is configured to project an incident electron beam to the surface of a sample to be measured and generate an electron beam image, and the electron beam imaging module 110 is usually used for defect detection and critical dimension measurement of production objects such as chips. Specifically, the electron beam imaging module 110 includes an electron beam emission source 111 and an exit electron detector 112, the electron beam emission source 111 is configured to generate and emit incident electrons, and the exit electron detector 112 is configured to receive at least one of secondary electrons and backscattered electrons generated by the projection of the incident electron beam to the sample to be measured and generate an electron beam image; the translation stage 120 is used to place the sample to be measured and is configured to drive the sample to be measured to translate in a preset plane 130; the first interferometer 140 is a high-precision and high-sensitivity measuring instrument using light waves as carriers and using laser as length reference, and the first interferometer 140 is configured to emit probe laser 170 along the first detection direction of the preset plane 130; the light splitting assembly 150 is arranged on the light path of the probe laser 170 and is configured to split the probe laser 170 into a plurality of parallel and spaced beam splitting lasers 180 emitted along the second detection direction, and the second detection direction is perpendicular to the first detection direction in the preset plane 130.
[0057] Optionally, the translation stage 120 is rectangular, and adjacent two sides of the translation stage 120 are parallel to the first detection direction and the second detection direction respectively. The translation stage 120 is configured to translate along the first detection direction and the second detection direction in the preset plane 130, and the movement range 131 is rectangular, and the first detection direction and the second detection direction are also parallel to adjacent two sides of the rectangular 131 respectively.
[0058] Those skilled in the art can understand that by making the first interferometer 140 emit probe laser 170 along the first detection direction of the preset plane 130, the light splitting assembly 150 is arranged on the light path of the probe laser 170, so that the probe laser 170 is split into a plurality of parallel and spaced beam splitting lasers 180 emitted along the second detection direction, wherein the second detection direction is perpendicular to the first detection direction in the preset plane 130. When the translation stage 120 moves beyond the measurement range of a beam splitting laser 180, that is, enters the measurement range of other beam splitting lasers 180, the full range position information measurement feedback of the translation stage 120 in the first detection direction is met, and the measurement accuracy is improved based on the measurement of the beam splitting laser 180.
[0059] Referring to Figure 2 and Figure 3 As shown, in some embodiments of the utility model, the light splitting assembly 150 includes:
[0060] At least one beam splitter 151 is arranged along the light path of the probe laser 170, and each beam splitter 151 forms a split laser 180 by reflecting light by itself;
[0061] A mirror 152 is arranged at the end of the light path of the probe laser 170, and reflects the transmitted light through the at least one beam splitter 151 along a second detection direction to form a split laser 180.
[0062] Those skilled in the art can understand that the at least one beam splitter 151 can be one or more, and the number of beam splitters can be determined according to the length of the travel of the translation stage 120 along the first detection direction. Specifically, the longer the travel, the more beam splitters are arranged, and the shorter the travel, the fewer beam splitters are arranged.
[0063] Those skilled in the art can understand that by arranging the beam splitting assembly 150 to include at least one beam splitter 151 and a mirror 152, the at least one beam splitter 151 is arranged along the light path of the probe laser 170, and the mirror 152 is arranged at the end of the light path of the probe laser 170, thereby reducing the cost of generating the split laser 180.
[0064] Still referring to Figure 2 and Figure 3 In some embodiments of the present application,
[0065] The at least one beam splitter 151 is one; and
[0066] The distance from the beam splitter 151 to the mirror 152 and to the first interferometer 140 is equal.
[0067] Those skilled in the art can understand that when the at least one beam splitter 151 is one, by arranging the distance from the beam splitter 151 to the mirror 152 and to the first interferometer 140 to be equal, when the translation stage 120 moves beyond the measurement range of one split laser 180 and enters the measurement range of another split laser 180, the full travel position information of the translation stage 120 in the first detection direction is measured and fed back.
[0068] Still referring to Figure 2 and Figure 3 In some embodiments of the present application,
[0069] The at least one beam splitter 151 is a plurality; and
[0070] The plurality of beam splitters 151 are arranged at equal intervals.
[0071] The person skilled in the art can understand that when the at least one beam splitter 151 is multiple, by arranging the multiple beam splitters 151 equidistantly, when the translation stage 120 moves to the measurement range of the other multiple beams of split laser 180, the full stroke position information measurement feedback of the translation stage 120 in the first detection direction is met.
[0072] Still referring to Figure 2 and Figure 3 As shown, the electron beam detection device 100 further comprises a second interferometer 160, the second interferometer 160 is also a high-precision and high-sensitivity measuring instrument taking light waves as carriers and using laser as length reference. The second interferometer 160 is arranged outside the side of the rectangle parallel to the second detection direction, and the arrangement position of the second interferometer 160 can correspond to the midpoint of the side, and the second interferometer 160 is configured to emit laser 190 directly to the sample to be measured along the first detection direction.
[0073] The person skilled in the art can understand that by arranging the second interferometer 160 outside the side of the rectangle parallel to the second detection direction, and making the second interferometer 160 emit laser 190 directly to the sample to be measured along the first detection direction, the full stroke position information measurement feedback of the translation stage 120 in the second detection direction is met.
[0074] In some embodiments of the utility model, the translation stage 120 is arranged in the vacuum chamber.
[0075] The person skilled in the art can understand that, because there are almost no gas molecules in the vacuum chamber, by arranging the translation stage 120 in the vacuum chamber, the collision between the electron beam and the gas can be reduced, and the detection accuracy of the sample to be measured can be improved.
[0076] At this point, the person skilled in the art should realize that, although the plurality of exemplary embodiments of the utility model have been shown and described in detail herein, many other variants or modifications conforming to the principles of the utility model can be directly determined or deduced according to the content disclosed by the utility model without departing from the spirit and scope of the utility model. Therefore, the scope of the utility model should be understood and recognized as covering all these other variants or modifications.
Claims
1. An electron beam detecting apparatus characterized by comprising: The electron beam detection device comprises: an electron beam imaging module configured to project an incident electron beam to a surface of a sample to be measured and generate an electron beam image; a translation stage for placing the sample to be measured and configured to drive the sample to be measured to translate in a preset plane; a first interferometer configured to emit a probe laser along a first probe direction of the preset plane; a light splitting assembly arranged in a light path of the probe laser and configured to split the probe laser into a plurality of parallel and spaced-apart split beams emitted along a second probe direction, and the second probe direction is perpendicular to the first probe direction in the preset plane.
2. The electron beam detection device according to claim 1, wherein the translation stage is configured to translate in the first probe direction and the second probe direction in the preset plane.
3. The electron beam detection device according to claim 2, wherein a moving range of the translation stage in the preset plane is configured as a rectangle, and the first probe direction and the second probe direction are respectively parallel to two adjacent sides of the rectangle.
4. The electron beam detection device according to claim 3, wherein the light splitting assembly is arranged outside a side of the rectangle parallel to the first probe direction.
5. The electron beam detection device according to claim 4, wherein the light splitting assembly comprises: at least one light splitting mirror arranged in the light path of the probe laser, and each light splitting mirror forms one of the split beams by reflecting light; a mirror arranged at an end of the light path of the probe laser and reflecting transmitted light through the at least one light splitting mirror along the second probe direction to form one of the split beams.
6. The electron beam detection device according to claim 5, wherein the at least one light splitting mirror is one; and distances from the light splitting mirror to the mirror and to the first interferometer are equal.
7. The electron beam detection device according to claim 5, wherein the at least one light splitting mirror is a plurality; and the plurality of light splitting mirrors are arranged at equal intervals.
8. The electron beam detection apparatus of claim 3, wherein The electron beam detection device further comprises: a second interferometer arranged outside a side of the rectangle parallel to the second probe direction and configured to emit a laser directly to the sample to be measured along the first probe direction.
9. The electron beam detection device according to claim 1, wherein the translation stage is configured to be arranged in a vacuum chamber.
10. The electron beam detection device according to claim 1, wherein the electron beam imaging module comprises an electron beam emission source configured to generate and emit the incident electron, and an exit electron detector configured to receive at least one of secondary electrons and backscattered electrons generated by the incident electron beam projected to the sample to be measured and generate the electron beam image.