KR-102959989-B1 - Integrated measurement system

KR102959989B1KR 102959989 B1KR102959989 B1KR 102959989B1KR-102959989-B1

Abstract

A measurement system configured to be integrated with processing equipment for applying optical measurement to a structure is provided. The measurement system comprises: a support assembly for holding the structure to be measured in a measurement plane—said to be configured and operable to rotate in a plane parallel to the measurement plane and to move along a first transverse axis in the measurement plane; An optical system defining illumination and collection optical channels of vertical and oblique optical methods—the optical system comprises an optical head including at least three lens units located in the illumination and collection channels; A holder assembly comprising a support unit and a guide unit—the support unit is configured to carry an optical head, and the guide unit is configured to guide the sliding movement of the support unit along a path extending along a second transverse axis perpendicular to the first transverse axis; The optical window array comprises at least three optical windows configured in a face plate located between the optical head at a specific distance from the measurement plane. The optical windows are aligned with the illumination and collection channels, respectively, for the propagation of illumination light from the optical head and for the propagation of light returning from the illuminated area to the optical head, according to the vertical and oblique optical methods.

Inventors

도탄 엘라드
반호트스케르 모쉬
얄로프 시몬
데이치 발레리
린젤 로이
슐만 베니
바 온 요시
바산 샤하르

Assignees

노바 엘티디.

Dates

Publication Date: 20260511
Application Date: 20191117
Priority Date: 20181119

Claims (20)

A measurement system configured to be integrated with processing equipment to apply optical measurements to a wafer, wherein the measurement system comprises: A support assembly for holding a wafer to be measured on a measurement plane—the support assembly is configured and operable to rotate in a plane parallel to the measurement plane and to move along a first transverse axis on the measurement plane; An optical system forming at least two illumination and collection channels of vertical and oblique optical types—the optical system comprises an optical head including at least three lens units located within the illumination and collection channels; A holder assembly comprising a support unit and a guide unit—the support unit is configured to carry an optical head, and the guide unit is configured and operable to guide the sliding movement of the support unit along a path extending along a second transverse axis perpendicular to the first transverse axis; An optical window array comprising at least three elongated optical windows configured in a face plate located between the optical head and the measurement plane at a specific distance from the measurement plane—the optical windows are arranged in a spaced-apart relationship in parallel and extend parallel to the path, and the optical windows are aligned with the illumination and collection channels, respectively, for the propagation of illumination light from the optical head and for the propagation of light returning from the illuminated area to the optical head, according to the vertical and oblique optical methods; comprising A measurement system comprising the optical system, the support assembly for holding the wafer, the support unit for carrying the optical head, and the optical window array configured to provide measurements at a plurality of measurement sites on the entire surface of the wafer.
A measurement system according to claim 1, further comprising a controller configured and operable to controllably shift the operation of the optical system between the vertical and inclined optical measurement methods.
A measuring system according to claim 1 or 2, further comprising a navigation motion system configured and operable to drive rotational motion of a support assembly and motions of a support unit of a support assembly and a holder assembly, respectively, along the first and second transverse axes.
In claim 1, the optical system comprises a common illumination assembly optically coupled with an illumination channel of a vertical and oblique optical measurement method, and individual detection devices accommodated in their respective collection channels of the vertical and oblique optical measurement method.
A measurement system according to claim 1, wherein each collection channel is configured to direct the collected mirror reflected light to spatially separated imaging and measurement channels.
A measurement system according to claim 5, wherein each collection channel comprises a pinhole mirror device for spatially separating the collected light into imaging and measurement light portions and directing it to propagate through the imaging and measurement channels.
In claim 6, the imaging and measurement channel is a measurement system optically coupled to an imaging and measurement detection device.
In claim 7, the measurement channels of the vertical and oblique optical methods are a measurement system optically coupled to the same spectroscopic detector.
A measuring system according to claim 1, wherein the optical head comprises at least three objective lens units positioned in a vertical and oblique optical manner, respectively.
In claim 9, the objective lens unit is a measuring system configured with low chromatic aberration.
In claim 1, the optical system comprises a measurement system including a polarization assembly comprising at least one polarizer located in at least one of an illumination and a collection channel.
In claim 11, the polarization assembly is located within an optical head and comprises three polarizers each located in vertical and inclined illumination and detection channels, respectively, in a measurement system.
A measurement system according to claim 1, wherein the optical window is configured to maintain the polarization of the light passing through.
A measuring system according to claim 1, wherein each optical window has a substantially uniform thickness along a length at least two orders of magnitude higher than the thickness.
A measuring system according to claim 14, wherein the thickness of the optical window is several millimeters.
A measuring system according to claim 1, wherein the face plate has a planar surface on which a central optical window is formed among the optical windows, and two inclined sides on the opposite side of the planar surface on which two other optical windows are formed among the optical windows, so that each optical window is positioned in a plane oriented 90 degrees with respect to the optical axis of each lens unit.
In claim 3, the navigation motion system comprises a driving assembly configured and operable to drive the sliding motion of a support unit of a holder assembly along a guide rail of a guide unit.
In claim 17, the drive assembly is a measuring system comprising a linear magnetic motor.
In claim 18, the linear magnetic motor is a measuring system comprising a movable magnet and a static coil assembly.
In claim 1, the support assembly is a measuring system configured and operable by a driving mechanism to control the position of a measuring plane relative to an optical head.

Description

Integrated measurement system The present invention relates to an optical measurement system for use in an integrated measurement/monitoring system, which is particularly useful in the semiconductor industry, in the field of measurement technology. The manufacturing of semiconductor devices consists of a multi-stage process that requires measuring wafers progressing on the production line between sequential manufacturing steps. Due to the semiconductor industry's trend toward dimensionality reduction and the dynamic nature of processes involved in semiconductor manufacturing, there is an increasing need for accurate diagnostic tools capable of providing near-real-time measurements for feedback loops that respond in short bursts, such as closed-loop control and feedforward control. These stringent requirements cannot be met by offline ("standalone") measurement systems that do not provide real-time responses, and such systems cannot be provided by on-site detection devices, such as endpoint detectors, because their performance is not sufficiently accurate. Integrated measurement and monitoring technology has been developed to provide the physical implementation of monitoring tools along with full measurement functions within the production lines of semiconductor manufacturing plants. An integrated measurement system is a system dedicated to a specific process, physically installed inside or attached to processing equipment. The integrated measurement system must be considered from various perspectives and meet specific requirements to be feasible. These requirements include, in particular, the following: 1) a small footprint—that is, the integrated measurement system must have the smallest possible footprint to be physically located within processing equipment, such as CMP equipment (e.g., connected to an Equipment Front-End Module (EFEM) via a load port or installed inside the processing equipment), such as isolating the measurement unit from the processing equipment environment (e.g., using a sealed enclosure); 2) high-speed measurement devices (e.g., rapid positioning, autofocus, and measurement); 3) optional features that allow it to bypass the production process and operate in offline mode, etc. Various integrated measurement/instrumentation systems, such as NovaScan® 3090Next and NOVA i500®, have been developed and are widely used and are being marketed by the assignee of this application. To better understand the subject matter disclosed in this specification and to illustrate how it can be actually carried out, embodiments will now be described only as non-limiting examples with reference to the accompanying drawings. Figure 1 is a diagram schematically illustrating an example of the integration of a measurement/instrumentation system and processing equipment. Figure 2 schematically shows the configuration of the integration of the integrated measurement/instrumentation system according to the invention. FIGS. 3a-3c illustrate specific, non-limiting examples of the configuration of a holder assembly for holding an optical head in the optical system of the present invention. FIGS. 4a-4d show the principle of a standard wedge design used in a Z-stage to transfer X-axis motion to Z-axis motion (Fig. 4a-4b), and a non-limiting specific example of a Z-stage configuration using a dual wedge engine suitable for use in the measurement system of the invention (Fig. 4c-4d). FIG. 5 illustrates the optical propagation method in the optical system of the integrated measurement/measurement system of the present invention configured for operation of the optical system having vertical and inclined operation modes. FIG. 6a schematically illustrates a plan view of an exemplary integrated measurement system of the present invention showing the range of movement of the optical window and wafer (support assembly) within the footprint of the system. FIG. 6b shows a typical geometric structure of a complex pattern structure measured on a wafer and demonstrates that the system configuration of the present invention can use a larger number of available azimuths (per pattern) for the inclined mode and use polarization azimuths for the normal mode for measurement. As described above, the present invention provides a measurement system configured to be integrated with processing equipment to apply optical measurements to a structure before or after it is processed by processing equipment. The processing equipment may include one or more processing tools, and while the structure proceeds through successive stages of the processing equipment, the measurement system may apply measurements to the structure before or after at least some of the processing stages. As described above, in some cases, the integrated measurement system may be located inside the processing equipment, and in other cases, the integrated measurement system is connected to the Equipment Front End Module (EFEM) via a load port. In the description below, the int