KR-102964766-B1 - Band-pass charged particle energy filtering detector for charged particle tools

Abstract

A method and system for detecting charged particles from a sample are provided. One system comprises a first repulsion mesh configured to repel charged particles from a sample having an energy less than a first predetermined energy, and a second repulsion mesh configured to repel charged particles passing through the first repulsion mesh having an energy less than a second predetermined energy. Additionally, the system comprises a first attraction mesh configured to attract charged particles passing through the first repulsion mesh and being repelled by the second repulsion mesh having an energy greater than a first predetermined energy and an energy less than a second predetermined energy. The system further comprises a first detector configured to generate an output in response to charged particles passing through the first attraction mesh.

Inventors

• 지앙 요우페이
• 슈타이거발트 마이클

Assignees

• 케이엘에이 코포레이션

Dates

Publication Date

20260513

Application Date

20221005

Priority Date

20211005

Claims (20)

1. As a system configured to detect charged particles from a sample, A first repelling mesh positioned in the path of a charged particle from a sample and configured to repel the charged particle having an energy smaller than a first predetermined energy; A second repulsion mesh configured to repel the charged particle having an energy smaller than the second predetermined energy that passes through the first repulsion mesh; A first attracting mesh configured to attract a charged particle that passes through the first repulsion mesh and is repelled by the second repulsion mesh, and has an energy greater than the first predetermined energy and less than the second predetermined energy; A first detector configured to generate an output in response to the charged particles passing through the first suction mesh; and A computer subsystem configured to systematically change the first and second predetermined energies by systematically changing the potential applied to the first repulsion mesh, the second repulsion mesh, and the first attraction mesh, compare the output generated by the first detector for at least two of the systematically changed potentials, and also select the potential applied to the first repulsion mesh, the second repulsion mesh, and the first attraction mesh for a process performed on the sample based on the result of comparing the outputs. A system including
2. In paragraph 1, A system in which the first repulsion mesh, the second repulsion mesh, and the first attraction mesh form a triangular energy band cavity.
3. In paragraph 1, A system in which the first repulsion mesh, the second repulsion mesh, and the first attraction mesh form at least a portion of a square energy band cavity.
4. In paragraph 1, A system further comprising a second detector configured to detect charged particles passing through the second repulsion mesh and an electrode block configured to at least partially surround the space between the first repulsion mesh and the second detector, wherein the first repulsion mesh, the second repulsion mesh, the first attraction mesh, and the electrode block form a square energy band cavity, and the second repulsion mesh and the electrode block have the same potential.
5. In paragraph 1, A system further comprising a second detector configured to detect the charged particles passing through the second repulsion mesh.
6. In paragraph 1, The above-mentioned first detector is a system that is grounded.
7. In paragraph 1, The above-mentioned first detector is a system biased with a positive voltage.
8. In paragraph 1, The above-mentioned first detector is a system biased with an adjustable voltage.
9. In paragraph 1, A system in which the first detector is biased by voltage, and the first suction mesh shields the space between the first repulsion mesh, the second repulsion mesh, and the first suction mesh from the electric field from the first detector.
10. In paragraph 1, A system further comprising a deflector configured to change the path position of the charged particle from the sample before the charged particle reaches the first repulsion mesh.
11. In Paragraph 10, A system further comprising a focusing lens configured to focus the charged particle from the deflector and to collimate the charged particle, having an energy greater than the first predetermined energy and less than the second predetermined energy, so as to pass through the first repulsion mesh.
12. In Paragraph 11, A system further comprising a differential potential electrode that surrounds the path of the charged particle between the focusing lens and the first repulsion mesh.
13. In Paragraph 12, A system in which the differential potential electrode is configured to reduce the formation of a lensing field between the focusing lens and the first repulsion mesh.
14. In paragraph 1, A system in which the energy band between the first and second predetermined energies is the same as the energy band from 0 eV to 50 eV.
15. In paragraph 1, A system in which the energy band between the first and second predetermined energies is the same as the energy band of Em-100 eV, and Em is the maximum emitted charged particle energy from the sample.
16. In paragraph 1, A system in which the energy band between the first and second predetermined energies is the same as the energy band of 50 eV-Em, and Em is the maximum emitted charged particle energy from the sample.
17. In paragraph 1, A system in which the first and second predetermined energies are selected based on the type of defect to be detected on the sample, based on the output generated by the first detector.
18. In paragraph 1, A system in which the first and second predetermined energies are selected based on the type of charged particle to be detected from the sample.
19. In paragraph 1, A system in which the energy band between the first and second predetermined energies corresponds to the energy of only secondary charged particles from the sample, and the computer subsystem is also configured to detect surface defects or voltage contrast defects on the sample based on the output generated by the first detector.
20. In paragraph 1, A system in which the energy band between the first and second predetermined energies corresponds to the energy of only elastic backscattering charged particles from the sample, and the computer subsystem is also configured to detect high aspect ratio or material contrast defects on the sample based on the output generated by the first detector.

Description

Band-pass charged particle energy filtering detector for charged particle tools The present invention generally relates to a method and system for detecting charged particles from a sample. A specific embodiment relates to a band-pass charged particle energy filtering detector for a charged particle tool. The following descriptions and examples are not considered prior art because they are included in this section. Manufacturing semiconductor devices, such as logic and memory devices, typically involves processing a substrate, such as a semiconductor wafer, through numerous semiconductor manufacturing processes to form various features and multiple levels of the semiconductor device. For example, lithography is a semiconductor manufacturing process that involves transferring a pattern from a reticle to a resist arranged on a semiconductor wafer. Additional examples of semiconductor manufacturing processes include, but are not limited to, chemical-mechanical polishing (CMP), etching, deposition, and ion implantation. Multiple semiconductor devices may be manufactured as an array on a single semiconductor wafer and then separated into individual semiconductor devices. The inspection process is used to increase profits by detecting defects in wafers and other substrates at various stages during semiconductor manufacturing, thereby facilitating higher yields in the manufacturing process. Inspection has always been a critical part of manufacturing semiconductor devices such as ICs. However, as the size of semiconductor devices shrinks, inspection becomes even more critical for the successful manufacturing of usable semiconductor devices, as even smaller defects can cause the device to fail. Defect review generally involves a step of re-detecting defects detected during the inspection process and a step of generating additional information about the defects at high resolution using a high-magnification optical system or a scanning electron microscope (SEM). Therefore, defect review is performed at individual locations on the specimen where defects were detected through inspection. The high-resolution data on defects generated by defect review is more suitable for determining defect attributes such as profiles, roughness, and more accurate size information. The metrology process is used to monitor and control the process at various stages during the semiconductor manufacturing process. The metrology process differs from the inspection process in that, unlike the inspection process where defects are detected on a sample, the metrology process is used to measure one or more characteristics of a sample that cannot be determined using currently used inspection tools. For example, the metrology process is used to measure one or more characteristics of a sample, such as the dimensions of features formed on the sample during the process (e.g., line width, thickness, etc.), so that the performance of the process can be determined from one or more characteristics. Furthermore, if one or more characteristics of the sample are unacceptable (e.g., outside a predetermined range for the characteristic(s), the measured values of one or more characteristics of the sample can be used to modify one or more parameters of the process so that additional samples manufactured by the process have acceptable characteristic(s). The measurement process differs from the defect review process in that it can be performed at a location where no defects are detected, unlike the defect review process in which defects detected by inspection are reconsidered. That is, unlike defect review, the location on the sample where the measurement process is performed can be independent of the results of the inspection process performed on the sample. In particular, the location where the measurement process is performed can be selected independently of the inspection results. Furthermore, unlike defect review, where the location on the sample where the defect review is performed cannot be determined until the inspection results for the sample are generated and become available, the location on the sample where the measurement is performed can be selected independently of the inspection results; thus, the location where the measurement process is performed can be determined before the inspection process is performed on the sample. In quality control processes such as inspection processes, defect review processes, and metrology using charged particles, such as electrons or ions, it is often important to detect only charged particles with specific energies from a sample. In particular, various types of charged particles returned from a sample can be somewhat sensitive to specific defects or measurements. Different types of charged particles can often be separated from each other because they have different energies. Various methods have been developed to separate charged particles with different energies, such as critical energy filters, energy dispersing sect