CN-121986301-A - Method of monitoring performance, method of manufacturing device, computer program and lithographic apparatus

CN121986301ACN 121986301 ACN121986301 ACN 121986301ACN-121986301-A

Abstract

A method of monitoring the performance of an immersion lithographic apparatus includes moving a test substrate relative to a liquid confinement structure through a series of test path portions while projecting exposure radiation through an immersion liquid onto a photosensitive layer on the test substrate such that the photosensitive layer is exposed, wherein the series of test path portions includes a first test path portion and a second test path portion, and the second test path portion is symmetrical to the first test path portion.

Inventors

G - L - Tobey and Gio
M. M. Vanni

Assignees

ASML荷兰有限公司

Dates

Publication Date: 20260505
Application Date: 20240912
Priority Date: 20231012

Claims (15)

1. A method of monitoring performance of an immersion lithographic apparatus, the method comprising: Moving a test substrate relative to a liquid confinement structure through a series of test path portions while projecting exposure radiation through an immersion liquid onto a photosensitive layer on the test substrate such that the photosensitive layer is exposed; Wherein the series of test route sections includes a first test route section and a second test route section, and The second test route portion is symmetrical with the first test route portion.
2. The method of claim 1, wherein the first test route portion and the second test route portion have a symmetry selected from the group consisting of mirror symmetry, rotational symmetry, and translational symmetry, desirably wherein the symmetry corresponds to the symmetry of the liquid confinement structure.
3. The method of claim 1 or 2, wherein the first and second test route portions are mirror symmetric about a line of symmetry passing through the center of the substrate, desirably wherein the test route portions further comprise third and fourth test route portions, wherein the third and fourth test route portions are symmetric with the first and second test route portions, respectively, about another line of symmetry passing through the center of the substrate and desirably perpendicular to the line of symmetry passing through the center of the substrate.
4. The method of claim 1 or 2, wherein the first and second test route portions are rotationally symmetric about an axis passing through the center of the substrate and perpendicular to the substrate.
5. The method of any of the preceding claims, wherein the series of test route sections includes a first additional test route section and a second additional test route section, and The second additional test route portion is symmetrical with the first additional test route portion but asymmetrical with the first test route portion or the second test route portion, and/or wherein at least one test route portion comprises at least one scanning section during which the test substrate moves along a substantially straight line at a substantially constant speed relative to the liquid confinement structure and at least one turning back section during which the test substrate moves along a curved path such that the direction of movement of the test substrate changes by 90 degrees relative to each other, and/or wherein at least one test route portion comprises an edge intersection during which at least a portion of the immersion space containing the immersion liquid intersects an edge of the test substrate.
6. The method of any preceding claim, further comprising analyzing the photosensitive layer after the exposure during the test route portion to determine a performance index of the immersion lithography apparatus, such as a bubble defect rate and/or a watermark rate.
7. The method of claim 6, wherein analyzing the photosensitive layer comprises developing the photosensitive layer, or wherein analyzing the photosensitive layer comprises detecting a latent image in the photosensitive layer.
8. A method of manufacturing a device using an immersion lithographic apparatus, the method comprising in order: exposing a first batch of production substrates to a device pattern using the immersion lithography apparatus; performing a method of monitoring the performance of the immersion lithographic apparatus according to any one of the preceding claims, and A second batch of production substrates is exposed to the device pattern using the immersion lithography apparatus.
9. The method of claim 8, wherein the production substrate moves relative to a liquid confinement structure of the immersion lithography apparatus along a production line during exposure to the device pattern, and At least one test route portion corresponds to a portion of the production route, desirably wherein for at least a portion of the test route portion, the test substrate moves faster than a production substrate moves during the corresponding portion of the production route, and/or further comprising a remedial action step based on the result of the monitoring step prior to the exposing of the second production substrate, wherein the remedial action is selected from the group consisting of: a maintenance action on the immersion lithography apparatus; Adjustment of operating parameters of the immersion lithographic apparatus, and And adjusting parameters of the production route.
10. A computer program comprising computer interpretable code which, when executed by a control system of an immersion lithographic apparatus, causes the immersion lithographic apparatus to perform a method according to any one of the preceding claims.
11. An immersion lithographic apparatus comprising: A liquid confinement structure; A positioner; a projection system for projecting a beam of radiation onto a substrate held by the positioner, and A controller configured to control the positioner and the projection system to: Moving a test substrate relative to a liquid confinement structure through a series of test path portions while projecting the beam of radiation through an immersion liquid onto a photosensitive layer on the test substrate such that the photosensitive layer is exposed; Wherein the series of test route sections includes a first test route section and a second test route section, and The second test route portion is symmetrical with the first test route portion.
12. The immersion lithographic apparatus of claim 11, wherein the first and second test route portions have a symmetry selected from the group consisting of mirror symmetry, rotational symmetry and translational symmetry, desirably wherein the symmetry corresponds to a symmetry of the liquid confinement structure, and/or wherein the first and second test route portions are mirror symmetric about a symmetry line passing through the center of the substrate, desirably wherein the test route portions further comprise a third and fourth test route portion, wherein the third and fourth test route portions are symmetric with the first and second test route portions, respectively, about another symmetry line passing through the center of the substrate and desirably perpendicular to the symmetry line passing through the center of the substrate.
13. The immersion lithography apparatus of claim 12, wherein the first test route portion and the second test route portion are rotationally symmetric about an axis passing through the center of the substrate and perpendicular to the substrate.
14. The immersion lithography apparatus according to any one of claims 11 to 13, wherein the series of test route portions comprises a first additional test route portion and a second additional test route portion, and The second additional test route portion is symmetrical with the first additional test route portion but asymmetrical with the first test route portion or the second test route portion, and/or wherein at least one test route portion comprises at least one scanning section during which the test substrate moves along a substantially straight line at a substantially constant speed relative to the liquid confinement structure and at least one turning back section during which the test substrate moves along a curved path such that the direction of movement of the test substrate changes by 90 degrees relative to each other, and/or wherein at least one test route portion comprises an edge intersection during which at least a portion of the immersion space containing the immersion liquid intersects an edge of the test substrate, and/or wherein the controller is further configured to control the positioner and the projection system to: exposing a first batch of production substrates to a device pattern using the immersion lithography apparatus before performing the step of moving the test substrate, and then A second batch of production substrates is exposed to the device pattern using the immersion lithography apparatus.
15. The immersion lithography apparatus of claim 14, wherein said controller is further configured to control said positioner and said projection system to move said production substrate along a production line relative to a liquid confinement structure of said immersion lithography apparatus during said exposing to said device pattern, and At least one test route portion corresponds to a portion of the production route, desirably wherein the controller is further configured to control the positioner and the projection system to move the test substrate for at least a portion of the test route portion at a speed that is faster than a speed of movement of a production substrate during the corresponding portion of the production route.

Description

Method of monitoring performance, method of manufacturing device, computer program and lithographic apparatus Cross Reference to Related Applications The present application claims priority from EP application 23203252.4 filed on 10/12 of 2023 and incorporated herein by reference in its entirety. Technical Field The present invention relates to a method of monitoring the performance of a lithographic apparatus, a method of manufacturing a device, a computer program and a lithographic apparatus. Background A lithographic apparatus is a machine that is configured to apply a desired pattern onto a substrate. For example, lithographic apparatus can be used to manufacture Integrated Circuits (ICs). For example, a lithographic apparatus may project a pattern (also commonly referred to as a "design layout" or "design") of a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate (e.g., a wafer). Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through the radiation beam in a given direction (the "scanning" -direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. As semiconductor fabrication processes continue to advance, the size of circuit elements has continuously decreased, while the number of functional elements (such as transistors) per device has steadily increased for decades, a trend being followed commonly known as 'moore's law. To keep pace with moore's law, the semiconductor industry is continually striving for techniques that enable smaller and smaller features to be created. To project a pattern on a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm. Further improvement in resolution of smaller features can be achieved by providing an immersion fluid (such as water) with a relatively high refractive index on the substrate during exposure. The effect of the immersion fluid is to enable imaging of smaller features, since the exposure radiation will have a shorter wavelength in the fluid than in the gas. The effect of immersion fluid can also be seen as increasing the effective Numerical Aperture (NA) of the system and also increasing the depth of focus. Immersion fluid may be confined to a localized area between the projection system of the lithographic apparatus and the substrate by the fluid handling structure. Disclosure of Invention In immersion lithography processes, defects may occur in the printed pattern due to the presence of bubbles in the immersion liquid and/or droplets of the immersion liquid that remain on the surface of the substrate. For example, many methods have been proposed to minimize the generation of such bubbles and droplets and improve their impact by providing a CO 2 environment near the immersion liquid, special coatings on the substrate and substrate support, extracting gases and liquids from the gap between the edge of the substrate and the substrate support, and varying scan lines and speeds. However, to date, it has not been possible to completely eliminate the occurrence of bubbles and droplets and their resulting drawbacks. In many cases, the defect rate can be reduced (yield increased) by reducing the scan speed or other recipe modifications that reduce throughput. Thus, the lithographic machine can select process parameters that balance throughput and throughput to maximize the production of functional devices. To achieve this balance, the performance of the lithographic apparatus must be monitored to avoid variations in machine performance (commonly referred to as drift) that adversely affect the output. One method of monitoring performance is to expose test substrates between production substrate lots using stage movement, a subset of the primary production routes known to be particularly prone to defects. The test substrate is inspected to immediately detect defects, the substrate is developed using only a minimum of process steps, and the defect rate is determined. If the defect rate is low, it may be necessary to expose a number of test substrates to accurately determine the defect rate, which reduces the time available to expose production substrates. According to the present invention there is provided a method of monitoring the performance of an immersion lithographic apparatus, the method comprising: moving the test substrate relative to the liquid confinement structure through a series of test path portions while projecting exposure radiation through the immersion liquid onto the photosensitive layer on the test substrate such that the photosensitive