CN-121986302-A - Multi-core waveguide for semiconductor metrology systems and methods

Abstract

Multicore waveguides, such as optical fibers, for use in semiconductor metrology systems and methods are described. The multi-core waveguide is configured to conduct radiation from the radiation source to structures in one or more layers of the patterned substrate, such as metrology targets, and to conduct diffracted and/or reflected radiation from the metrology targets to the radiation sensor. The length of the multicore waveguide is configured to facilitate placement of the radiation source and/or radiation sensor relative to the patterned substrate in spaced apart positions. The length of the multi-core waveguide is configured to provide increased functional space for other components of the metrology system (e.g., various lenses and/or other optical components) located near the patterned substrate.

Inventors

• S.A. GORDON
• SOKOLOV SKIFF
• J-B.M-Y. Heinrich
• S.R. Hughesman
• K. Abrahitova
• L. V. Amitonova

Assignees

• ASML荷兰有限公司

Dates

Publication Date

20260505

Application Date

20240903

Priority Date

20231012

Claims (15)

1. 1. A semiconductor metrology system, comprising: a radiation source configured to radiate structures in one or more layers of the patterned substrate; A radiation sensor configured to generate a metrology signal based on diffracted and/or reflected radiation received from the structure, the metrology signal comprising metrology information for the one or more layers, and One or more multi-core waveguides configured to conduct radiation from the radiation source to the structure and conduct the diffracted and/or reflected radiation from the structure to the radiation sensor, the length of the one or more multi-core waveguides configured to facilitate placement of the radiation source and/or the radiation sensor relative to the patterned substrate in spaced apart locations.
2. 2. The system of claim 1, further comprising one or more substrate-side lenses configured to focus the radiation from the radiation source onto the structure and direct the diffracted and/or reflected radiation from the structure into the one or more multicore waveguides.
3. 3. The system of claim 2, wherein the one or more substrate-side lenses comprise a substrate-side microlens array.
4. 4. The system of claim 3, wherein the number of lenses in the substrate-side microlens array corresponds to the number of cores in the one or more multicore waveguides.
5. 5. The system of claim 4, wherein the length of the one or more multicore waveguides is configured to facilitate placement of the radiation source and/or the radiation sensor relative to the patterned substrate in spaced apart locations so as to provide increased functional space for other components of the metrology system located in proximity to the patterned substrate, the other components including the substrate-side microlens array.
6. 6. The system of any one of claims 1 to 5, further comprising one or more source and sensor side lenses configured to direct the radiation from the radiation source into the one or more multicore waveguides and direct the diffracted and/or reflected radiation from the substrate conducted through the one or more multicore waveguides toward the radiation sensor.
7. 7. The system of claim 6, wherein the one or more source and sensor side lenses comprise a source and sensor side microlens array.
8. 8. The system of claim 7, wherein the number of lenses in the source and sensor side microlens array corresponds to the number of cores in the one or more multicore waveguides.
9. 9. The system of any of claims 1-8, wherein the spaced apart locations comprise locations remote from a side of the patterned substrate comprising the structure and the one or more layers.
10. 10. The system of any one of claims 1-9, wherein the length of the one or more multicore waveguides is up to about 0.1 meters, 0.25 meters, 0.5 meters, 1 meter, or 10 meters.
11. 11. The system of any of claims 1to 10, wherein the radiation source is configured to generate spatially incoherent and/or partially coherent radiation, and the radiation from the radiation source comprises a plurality of modes.
12. 12. The system of claim 11, wherein the number of the plurality of modes corresponds to a number of cores in the one or more multicore waveguides.
13. 13. The system of claim 12, wherein the number of cores is a total number of cores.
14. 14. The system of claim 12, wherein the number of cores is a subset of a total number of cores when the one or more multi-core waveguides are in a fourier and/or pupil plane with respect to the patterned substrate.
15. 15. The system of any one of claims 1 to 14, wherein each core of the one or more multicore waveguides conducts a single spatial mode of radiation.

Description

Multi-core waveguide for semiconductor metrology systems and methods Cross Reference to Related Applications The present application claims priority from U.S. application 63/543,762 filed on 10/12 of 2023, which is incorporated herein by reference in its entirety. Technical Field The present specification relates to multicore waveguides for use in semiconductor metrology systems and methods. Background Lithographic projection apparatus can be used, for example, in the manufacture of Integrated Circuits (ICs). The patterning device (e.g., mask) may comprise or provide a pattern corresponding to an individual layer of the IC (the "design layout"), and this pattern may be transferred to a target portion (e.g., comprising one or more dies) of a substrate (e.g., a silicon wafer) that has been coated with a layer of radiation-sensitive material (the "resist"), such as by irradiating the target portion with the pattern on the patterning device. Typically, a single substrate comprises a plurality of adjacent target portions to which the pattern is successively transferred one by the lithographic projection apparatus. In one type of lithographic projection apparatus, the pattern on the entire patterning device is transferred to a target portion in one operation. Such devices are commonly referred to as steppers. In an alternative arrangement (commonly referred to as a step-and-scan arrangement), the projection beam scans the patterning device in a given reference direction (the "scanning" direction) while simultaneously moving the substrate parallel or anti-parallel to the reference direction. Different portions of the pattern on the patterning device are transferred to one target portion in steps. The substrate may undergo various processes, such as priming, resist coating, and soft baking, prior to transferring the pattern from the patterning device to the substrate. After exposure, the substrate may be subjected to other processes ("post-exposure processes") such as post-exposure bake (PEB), development, hard bake, and measurement/inspection of the transferred pattern. This series of processes is used as a basis for fabricating individual layers of a device (e.g., an IC). The substrate may then be subjected to various processes, such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., which are intended to complete the individual layers of the device. If the device requires multiple layers, the entire process or variations thereof are repeated for each layer. Eventually, the device will appear in each target portion on the substrate. These devices are then separated from each other by techniques such as dicing or sawing so that the individual devices can be mounted on a carrier, connected to pins, etc. The device manufacturing process may be considered a patterning process. Patterning processes involve patterning steps, such as optical and/or nanoimprint lithography using a patterning device in a lithographic apparatus to transfer a pattern on the patterning device to a substrate, and typically (but optionally) involve one or more associated pattern processing steps, such as resist development by a developing device, baking the substrate using a bake tool, etching using a pattern using an etching device, deposition, etc. Photolithography is a central step in the fabrication of devices such as ICs, where patterns formed on a substrate define the functional elements of the device, such as microprocessors, memory chips, and the like. Similar photolithographic techniques are also used to form flat panel displays, microelectromechanical systems (MEMS), and other devices. As semiconductor fabrication processes continue to advance, the size of the functional elements continues to decrease, while the number of functional elements (such as transistors) per device steadily increases over the past decades, following a trend commonly referred to as "moore's law. In the state of the art, device layers are manufactured using lithographic projection apparatus that project a design layout onto a substrate using a deep ultraviolet illumination source, thereby creating individual functional elements that are well below 100nm in size (i.e., less than half the wavelength of radiation from the illumination source (e.g., 193nm illumination source)). This process of printing features in a size smaller than the classical resolution limit of a lithographic projection apparatus is commonly referred to as low-k 1 lithography according to the resolution formula cd=k 1 ×λ/NA, where λ is the wavelength of the radiation employed (currently in most cases 248nm or 193 nm), NA is the numerical aperture of the projection optics in the lithographic projection apparatus, CD is the "critical dimension" -typically the smallest printed feature size-and k 1 is the empirical resolution factor. In general, the smaller the k 1, the more difficult it is to reproduce a pattern on the substrate tha