A contamination detection device and a detection method for an immersion unit

Abstract

The present invention discloses a contamination detection device and method for an immersion unit. The device comprises: a tooling support assembly is fixedly connected to the lower end surface of the immersion unit, a slide rail is installed in the chamber formed between the immersion unit and the tooling support assembly, a motion motor drives the camera to move on the slide rail of the tooling support assembly according to a specified trajectory, and the camera is connected to the controller through a connecting cable. The method comprises: the camera performs multi-point shooting of all immersion supply openings and immersion recovery openings to obtain multiple local images and transmits them to the controller, the controller splices the multiple local images and detects whether there is a situation where the immersion supply opening and the immersion recovery opening are blocked by contaminants. The present invention regularly detects and cleans the blockage of contaminants, thereby ensuring the stable operation of the flow field and improving the performance and reliability of the lithography machine. The convenient operation of multi-point shooting avoids the unreliability of manual alignment and improves the convenience of operation.

Description

Technical Field

[0001] The present invention relates to the technical field of immersion lithography, and in particular to a contamination detection device and a detection method for an immersion unit. Background Art

[0002] Projection lithography is one of the core equipment for large-scale integrated circuit manufacturing. It uses a laser of a certain wavelength to illuminate the mask, and then transfers the pattern on the mask to the photoresist on the silicon wafer through the projection lens. After exposure, the silicon wafer undergoes subsequent development, etching, deposition, ion implantation, polishing, testing, cutting, welding, packaging and other processes to finally form a chip.

[0003] The immersion lithography machine fills the space between the last lens of the projection objective and the silicon wafer with an immersion liquid of high refractive index, thereby improving the lithography resolution and achieving a higher and smaller process line width. Due to the precipitation of substances and photochemical reactions of the photoresist in the immersion liquid, contaminants will be formed in the immersion liquid. The heat generated during the exposure process will also cause the temperature of the immersion liquid to rise. Therefore, it is necessary to continuously update the immersion liquid in the exposure area and stabilize the flow to reduce immersion exposure defects and ensure lithography performance. The immersion unit is arranged radially outside the last lens of the projection objective and is located on the silicon wafer. It has an immersion supply opening and an immersion recovery opening. The immersion liquid is provided to the gap between the last lens and the silicon wafer through the immersion supply opening, and the immersion liquid is recovered from the gap between the last lens and the silicon wafer through the immersion recovery opening, thereby forming an immersion flow field.

[0004] Since the size of the immersion liquid supply opening and the immersion liquid recovery opening is in the micron level, particles, microclusters, fibers and other pollutants in the immersion flow field can easily cause blockage, thereby affecting the stability of the immersion flow field. In severe cases, it may cause flow field leakage, affecting the performance and reliability of the lithography machine. Therefore, in the application of immersion lithography machines, it is necessary to regularly detect the contaminant blockage of the immersion unit. Summary of the invention

[0005] In view of the problem of contaminants formed by immersion liquid in the field of immersion lithography technology, the present invention provides a contamination detection device and a detection method for an immersion unit, which can realize regular detection of the contaminant blockage of the immersion unit, judge the blockage through image recognition, and guide the subsequent cleaning of the immersion unit to ensure stable operation of the flow field and improve the performance and reliability of the lithography machine.

[0006] The technical solution adopted by the present invention is:

[0007] 1. A contamination detection device for an immersion unit:

[0008] The pollution detection device is fixedly connected to the lower end surface of the immersion unit, and a projection objective lens is arranged on the upper end surface of the immersion unit;

[0009] The pollution detection device includes a tooling support assembly, a camera, a motion motor and a controller;

[0010] The lower end surface of the immersion unit is provided with a plurality of immersion liquid supply openings and a plurality of immersion liquid recovery openings, and the lower end surface of the immersion unit is fixedly connected to a tooling support assembly, and a closed vacuum chamber is formed between the immersion unit and the tooling support assembly, and a slide rail is installed in the chamber, and a motion motor is installed in the slide rail. The motion motor moves in the slide rail and drives the camera connected to itself to move, and the camera is arranged in a direction toward the immersion liquid supply opening and the immersion liquid recovery opening. The camera is connected to the controller through a connecting cable, and a mechanical slide rail with a specified contour is used to realize convenient multi-point shooting operation, avoid the unreliability of manual alignment, and improve the convenience of operation.

[0011] The tooling bracket assembly comprises a tooling bracket and a connecting piece; a plurality of connecting pieces are mounted on the surface of the tooling bracket, and the tooling bracket is fixedly assembled correspondingly to the tooling interfaces opened on the surface of the immersion unit through the plurality of connecting pieces.

[0012] The slide rail is installed on the inner wall surface of the tooling bracket directly facing the multiple immersion liquid supply openings and the multiple immersion liquid recovery openings, and the distance between the camera and an end surface of the immersion unit is within the focal depth range of the camera.

[0013] The camera has a macro shooting function with a micron-level aperture.

[0014] 2. Detection method of contamination detection device of immersion unit:

[0015] 1) The controller controls the motion motor to move the camera in the slide rail;

[0016] 2) The camera takes multiple shots of all the immersion liquid supply openings and immersion liquid recovery openings while moving in the slide rail to obtain multiple local images, and the multiple local images are transmitted to the controller through the connecting cable;

[0017] 3) The controller stitches the multiple partial images together to obtain a complete image, and detects the complete image to determine whether there is a situation where contaminants block the immersion liquid supply opening and the immersion liquid recovery opening.

[0018] In the step 2), the shape of the slide rail is set according to the overall outline formed by all the immersion liquid supply openings and the immersion liquid recovery openings.

[0019] In the step 2), the multi-point shooting is specifically as follows: according to the size of the immersion supply opening and the immersion recovery opening, the magnification of the camera and the moving step of the motion motor are adjusted to shoot, and each local image contains at least two immersion supply openings and one immersion recovery opening.

[0020] In the step 3), multiple local images are stitched together, and an immersion supply opening shape, an immersion recovery opening shape, and the positional relationship between the two in the local images are used as feature points. The nth and n+1th local images captured are matched through the feature points for image alignment, and then image fusion and stitching operations are performed to obtain a complete image.

[0021] The present invention controls assembly through mechanical horizontal and vertical dimension chains, thereby ensuring that the camera can obtain a better macro shooting effect, avoiding the unreliability of manual alignment and focusing, and improving the convenience of operation; the controller has automatic image stitching and automatic image recognition functions, thereby avoiding the unreliability of manual analysis and judgment, and improving the process quality and convenience of operation.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention regularly detects and cleans the contaminant blockage of the immersion unit, thereby ensuring stable operation of the flow field and improving the performance and reliability of the lithography machine.

[0024] 2. The present invention controls the assembly through mechanical horizontal and vertical dimension chains, thereby ensuring that the camera can obtain a better macro shooting effect, avoiding the unreliability of manual alignment and focusing, and improving the convenience of operation.

[0025] 3. The present invention realizes the convenient operation of multi-point shooting through the mechanical slide rail with a specified contour, avoids the unreliability of manual alignment, and improves the convenience of operation.

[0026] 4. The present invention avoids the unreliability of manual analysis and judgment through automatic image stitching function and automatic image recognition function, and improves process quality and operational convenience. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a pollution detection device for an immersion unit of the present invention.

[0028] Figure 2 It is a schematic diagram of the structure of an immersion unit in which the immersion liquid supply opening and the immersion liquid recovery opening are arranged in a diamond shape.

[0029] Figure 3 It is a schematic diagram of the structure of an immersion unit in which the immersion liquid supply opening and the immersion liquid recovery opening are arranged in a circle.

[0030] Figure 4 It is a schematic diagram of the camera in the device of the present invention moving on the slide rail according to the square outline.

[0031] Figure 5 It is a schematic diagram of the camera in the device of the present invention moving along a circular profile on a slide rail.

[0032] Figure 6 It is a schematic diagram of the automatic control process of pollution detection in the device of the present invention.

[0033] Figure 7 It is a schematic diagram of the principles of multi-point shooting and image stitching.

[0034] In the figure: 10, immersion unit, 20, projection lens, 30, tooling bracket assembly, 40, camera, 50, motion motor, 60, controller, 70, connecting cable, 11, immersion liquid recovery opening, 12, immersion liquid supply opening, 13, mechanical interface, 31, tooling bracket, 32, connector, 33, slide rail DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown, the pollution detection device includes a tool support assembly 30, a camera 40, a motion motor 50 and a controller 60; the pollution detection device is fixedly connected to one end face of the immersion unit 10, the immersion unit 10 is arranged on the radial outer side of the last lens of the projection objective 20, one end face of the immersion unit 10 is provided with a plurality of immersion liquid supply openings 12 and a plurality of immersion liquid recovery openings 11, and is fixedly connected to the tool support assembly 30, the tool support assembly 30 is equipped with a slide rail 33, the slide rail 33 is equipped with a motion motor 50, the motion motor 50 moves in the slide rail 33 and drives the camera 40 connected to it to move, the camera 40 is arranged in the direction toward the immersion liquid supply opening 12 and the immersion liquid recovery opening 11, and the camera 40 is connected to the controller 60 through a connecting cable 70;

[0037] The tooling bracket assembly 30 includes a tooling bracket 31 and a connecting piece 32; a plurality of connecting pieces 32 are installed on the surface of the tooling bracket 31, and the tooling bracket 31 is fixedly assembled corresponding to the mechanical interface 13 opened on the surface of the immersion unit 10 through the plurality of connecting pieces 32, and a chamber for the camera 40 to move is formed between the tooling bracket 31 and the immersion unit 10; the camera 40 has a high zoom factor and a certain depth of focus, as well as an autofocus function. The high zoom factor and the autofocus function ensure that the camera has a macro shooting function with a micron-level small hole, and the connection height of the tooling bracket assembly 30 ensures that the camera 40 is just within the depth of focus range.

[0038] like Figure 4 , Figure 5 As shown, the tooling bracket 31 is provided with a slide rail 33 which is consistent with the overall outer contour of the immersion liquid supply opening 12 and the immersion liquid recovery opening 11 of the immersion unit 10. Figure 4 The slide rail 33 is square in shape. Figure 4The slide rail 33 is circular in shape and a mechanical slide rail with a specified contour ensures that multi-point shooting can be carried out conveniently, avoids the unreliability of manual alignment, and improves the convenience of operation; the slide rail 33 is installed on the inner wall surface of the tooling bracket 31 facing the multiple immersion supply openings 12 and the multiple immersion recovery openings 11; the controller 60 has a pollution detection automatic control process function. The controller 60 controls the movement of the motor 50 to drive the camera 40 to slide on the slide rail 33 of the tooling bracket 31, thereby performing multi-point shooting of all the immersion supply openings 12 and the immersion recovery openings 11 of the immersion unit 10 to obtain multiple local pictures.

[0039] like Figure 2 As shown, there are a series of immersion liquid supply openings 12 (round holes) and immersion liquid recovery openings 11 (square holes) arranged in a diamond shape on the immersion unit 10, and there are three mechanical interfaces 13 fixedly connected to the connecting member 32 of the pollution detection device.

[0040] like Figure 3 As shown, there are a series of immersion liquid supply openings 12 (round holes) and immersion liquid recovery openings 11 (square holes) arranged in a circular pattern on the immersion unit 10 , and there are three mechanical interfaces 13 fixedly connected to the connecting member 32 of the pollution detection device.

[0041] like Figure 6 As shown, the detection method of the pollution detection device of the present invention comprises the following steps:

[0042] 1) The controller 60 controls the motion motor 50 to move and drive the camera 40 to move in the slide rail 33;

[0043] 2) While the camera 40 moves in the slide rail 33, it takes multi-point shots of all the immersion supply openings 12 and the immersion recovery openings 11 to obtain multiple local images. The multiple local images are transmitted to the controller 60 through the connecting cable 70. The shape of the slide rail 33 is set according to the overall contour formed by all the immersion supply openings 12 and the immersion recovery openings 11. When the local image is taken, the magnification and field of view of the camera 40, the movement direction and step distance of the motor and other parameters are set according to the sizes of the immersion supply openings 12 and the immersion recovery openings 11. Each local image contains at least 2 immersion supply openings and 1 immersion recovery opening.

[0044] 3) The controller 60 stitches multiple local images, uses an immersion supply opening shape, an immersion recovery opening shape, and the positional relationship between the two in the local images as feature points, matches the nth and n+1th local images captured through the feature points for image alignment, and performs image fusion and stitching operations to obtain a complete image, and detects the complete image to determine whether there are contaminants blocking the immersion supply opening 12 and the immersion recovery opening 11.

[0045] The present invention has automatic image stitching and automatic image recognition functions through the controller, which avoids the unreliability of manual analysis and judgment, improves the process quality and operational convenience, and regularly detects and cleans the contaminant blockage of the immersion unit, thereby ensuring the stable operation of the flow field and improving the performance and reliability of the lithography machine.

Claims

1. A contamination detection device for an immersion unit, wherein the contamination detection device is fixedly connected to the lower end surface of the immersion unit (10), and a projection objective lens (20) is arranged on the upper end surface of the immersion unit (10), characterized in that: The pollution detection device comprises a tool support assembly (30), a camera (40), a motion motor (50) and a controller (60); a plurality of immersion liquid supply openings (12) and a plurality of immersion liquid recovery openings (11) are provided on the lower end surface of the immersion unit (10); the tool support assembly (30) is fixedly connected to the lower end surface of the immersion unit (10); a sealed vacuum chamber is formed between the immersion unit (10) and the tool support assembly (30); a slide rail (33) is installed in the chamber; a motion motor (50) is installed in the slide rail (33); the motion motor (50) moves in the slide rail (33) and drives the camera (40) connected to the motion motor (50) to move; the camera (40) is arranged in a direction toward the immersion liquid supply opening (12) and the immersion liquid recovery opening (11); the camera (40) is connected to the controller (60) via a connecting cable (70); The contamination detection device is used in a photolithography machine; The tool support assembly (30) comprises a tool support (31) and a connecting piece (32); The surface of the tooling bracket (31) is provided with a plurality of connecting pieces (32), and the tooling bracket (31) is fixedly assembled correspondingly via the plurality of connecting pieces (32) and tooling interfaces provided on the surface of the immersion unit (10); The slide rail (33) is mounted on an inner wall surface of the tooling bracket (31) directly facing the plurality of immersion liquid supply openings (12) and the plurality of immersion liquid recovery openings (11).

2. The contamination detection device for an immersion unit according to claim 1, characterized in that: The distance between the camera (40) and an end surface of the immersion unit (10) is within the focal depth range of the camera (40).

3. The detection method applied to the pollution detection device according to any one of claims 1-2, characterized in that: The method comprises the following steps: 1) The controller (60) controls the motion motor (50) to move and drive the camera (40) to move within the slide rail (33); 2) the camera (40) takes multi-point photographs of all the immersion liquid supply openings (12) and the immersion liquid recovery openings (11) while moving in the slide rail (33) to obtain a plurality of local images, and the plurality of local images are transmitted to the controller (60) via the connecting cable (70); 3) The controller (60) stitches the multiple partial images together to obtain a complete image, and detects the complete image to determine whether there is a situation where contaminants block the immersion liquid supply opening (12) and the immersion liquid recovery opening (11).

4. The detection method of the pollution detection device according to claim 3, characterized in that: In the step 2), the shape of the slide rail (33) is set according to the overall contour formed by all the immersion liquid supply openings (12) and the immersion liquid recovery openings (11).

5. The detection method of the pollution detection device according to claim 3, characterized in that: In the step 2), the multi-point shooting specifically comprises: adjusting the magnification of the camera (40) and the moving step of the motion motor (50) according to the size of the immersion liquid supply opening (12) and the immersion liquid recovery opening (11) to shoot, and each local image contains at least two immersion liquid supply openings (12) and one immersion liquid recovery opening (11).

6. The detection method of the pollution detection device according to claim 3, characterized in that: In the step 3), an immersion supply opening shape, an immersion recovery opening shape, and the positional relationship between the immersion supply opening and the immersion recovery opening in the local image are used as feature points, and the nth and n+1th local images captured are matched through the feature points to perform image alignment, and then image fusion and stitching operations are performed to obtain a complete image.

7. The detection method of the pollution detection device according to claim 3, characterized in that: The camera (40) has a macro shooting function with a micron-level aperture.

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