Optical alignment assembly for exposure machine

Abstract

The utility model relates to an optical alignment assembly for an exposure machine. The optical alignment assembly comprises two optical alignment devices and a double-sided reflecting mirror, the double-sided reflecting mirror is vertically arranged on a position to be aligned of a working platform and is provided with a first vertical reflecting surface and a second vertical reflecting surface opposite to the first vertical reflecting surface, and the first vertical reflecting surface and the second vertical reflecting surface are respectively and optically coupled with the semi-transparent mirror. The double-sided reflector is provided with at least one preset pattern for imaging to an image acquisition assembly, and the preset pattern is used as a positioning reference of the to-be-aligned light.

Description

Technical Field

[0001] This utility model relates to an optical alignment component, and more particularly to an optical alignment component for use in an exposure machine. Background Technology

[0002] The photomask is a crucial component in semiconductor lithography technology. Before exposure and development, optical alignment is required. Its main function is to ensure that the pattern on the photomask is accurately aligned with the substrate during exposure to form the desired structure and minimize errors. The optical components of a photomask typically include a high-precision optical system, an alignment camera, and a control system.

[0003] The optical alignment component of a conventional exposure machine consists of a flat mirror placed on a work platform to receive the light to be aligned, and an inclined mirror optically coupled to the flat mirror. The flat mirror is engraved with a pattern. When the light to be aligned is reflected by the flat mirror to the inclined mirror, the inclined mirror reflects the light and the pattern into the image capturing element to form an image. If the platform position is correct, the pattern image will appear within a reasonable range. A typical configuration can be seen in Chinese Patent Publication No. CN103246170B. Utility Model Content

[0004] The main purpose of this invention is to solve the problem of excessively large size of the alignment mirror in conventional exposure machines.

[0005] To achieve the above objectives, this utility model discloses an optical alignment assembly for an exposure machine, comprising two optical alignment devices and a double-sided mirror. The two optical alignment devices are respectively located at both ends of a work stage, horizontally symmetrically arranged relative to a position to be aligned, and each includes a half-lens to receive and guide a light beam to be aligned to a first and a second orientation, and an image capturing component optically coupled to the half-lens and receiving the light beam to be aligned from the half-lens at the second orientation. The double-sided mirror is vertically disposed at the position to be aligned on the work stage and has a first vertical reflecting surface and a second vertical reflecting surface opposite the first vertical reflecting surface, both optically coupled to the half-lens. The double-sided mirror has at least one preset pattern, and receives the light beam to be aligned traveling along the first orientation from the half-lens. An image captured by the image capturing component shows a reflected light beam from the double-sided mirror and the preset pattern, serving as a positioning reference for the light beam to be aligned.

[0006] In one embodiment, each of the two sides of the double-sided reflector includes a preset pattern, and the preset patterns overlap along a normal direction of the double-sided reflector.

[0007] In one embodiment, the preset pattern includes ring, circle, square, or cross symbols.

[0008] In one embodiment, the light source is ultraviolet light, deep ultraviolet light, or super ultraviolet light.

[0009] In one embodiment, there is an angle between the light ray to be aligned and a reflective surface of the semi-transparent lens, the angle being between 25° and 65°. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the optical path of an exposure machine according to an embodiment of the present invention;

[0011] Figure 2A This is a schematic diagram of a preset pattern in one embodiment of the present utility model;

[0012] Figure 2B This is a schematic diagram of a preset pattern in another embodiment of the present utility model;

[0013] Figure 2C This is a schematic diagram of a preset pattern in another embodiment of the present utility model;

[0014] Figure 2D This is a schematic diagram of a preset pattern in another embodiment of the present utility model.

[0015] [Symbol Explanation]

[0016] 10: Light source

[0017] 11: Aim for the light

[0018] 20: Mirror assembly

[0019] 20a: First reflecting magnifying glass

[0020] 20b: Second reflecting magnifying glass

[0021] 30: Lens Group

[0022] 30a: First lens

[0023] 30b: Second lens

[0024] 40: Optical alignment assembly

[0025] 41: Double-sided mirror

[0026] 411: First vertical reflecting surface

[0027] 412: Second vertical reflecting surface

[0028] 413: Preset Pattern

[0029] 413a: Ring

[0030] 413b: Circular

[0031] 413c: Square

[0032] 413d: Cross mark

[0033] 42: Optical alignment device

[0034] 421: Semi-transparent lens

[0035] 422: Image Capture Component

[0036] 50: Work platform

[0037] 60: First Beam

[0038] 70: Second Beam

[0039] θ: included angle

[0040] d: interval Detailed Implementation

[0041] The terminology used herein is for the purpose of illustrating particular embodiments only and is not intended to limit the invention. Unless the context otherwise indicates, the singular forms “a” and “the” used herein may also include the plural forms.

[0042] The directional terms used herein, such as up, down, left, right, front, back, and their derivatives or synonyms, refer to the orientation of the elements in the accompanying drawings and are not intended to limit the present invention, unless the context clearly states otherwise.

[0043] This invention relates to an optical alignment component for an exposure machine, specifically an optical alignment component including a vertically positioned mirror for calibrating the light source of the exposure machine. This vertically positioned double-sided mirror differs from conventional horizontally placed techniques, eliminating the need to adjust the mirror size according to the stage or substrate size, thus reducing the weight, volume, and manufacturing cost of the alignment mirror in large exposure machines. The alignment pattern of this double-sided mirror is engraved at the same position on both sides to reduce alignment errors and further improve alignment accuracy.

[0044] Figure 1 This is a schematic diagram of the optical path of an exposure machine according to an embodiment of the present invention, specifically showing the imaging optical path. The exposure machine includes a light source 10, a mirror group 20, a lens group 30, an optical alignment component 40, and a work stage 50. In this example, the exposure machine is a stepper exposure machine. The light source 10 is optically coupled to the mirror group 20, the lens group 30, and the optical alignment component 40. The work stage 50 is used to support the optical alignment component 40 and the substrate to be exposed. The exposure machine can be dry or immersion type.

[0045] Before exposure, alignment is required, a step crucial to the accuracy of the circuit pattern and overall yield. The light source 10 can use visible light of a specific wavelength (e.g., between 400 nm and 700 nm), white light composed of a mixture of different wavelengths of visible light, ultraviolet light with wavelengths between 280 nm and 400 nm (e.g., G-line or I-line), deep ultraviolet light with wavelengths between 100 nm and 280 nm (e.g., KrF or ArF), or ultraviolet light with wavelengths between 10 nm and 100 nm (e.g., tin plasma) during the alignment process.

[0046] The reflector assembly 20 is used to receive a beam of light 11 to be aligned emitted by the light source 10. The reflector assembly 20 can be a coated distributed Bragg reflector (DBR), and the coating material can be Mo / Si multilayer film, TiO2, or SiO2, etc., to improve light reflectivity. The reflector assembly 20 can include one or more reflective magnifying lenses that are optically coupled to each other. In this embodiment, the reflector assembly 20 includes a first reflective magnifying lens 20a and a second reflective magnifying lens 20b. The first reflective magnifying lens 20a is directly optically coupled to the light source 10 to reflect the beam of light 11 to be aligned to the second reflective magnifying lens 20b, and then to the lens assembly 30. The number and configuration of the reflective magnifying lenses in the reflector assembly 20 can be adjusted according to requirements, such as spatial configuration. This utility model is not limited to this example.

[0047] The lens group 30 receives the alignment light 11 from the mirror group 20. The lens group 30 is used to change the size of the projection, homogenize the alignment light 11, and correct optical aberrations to ensure image quality. The lens group 30 may include one or more concave lenses, convex lenses, or any combination thereof. In this example, the lens group 30 includes a first lens 30a and a second lens 30b, where the first lens 30a is a concave lens and the second lens 30b is a convex lens.

[0048] The optical alignment assembly 40 includes a double-sided mirror 41 and two optical alignment devices 42. Each of the two optical alignment devices 42 includes a half-lens 421 and an image capturing assembly 422. The optical alignment assembly 40 is located below the lens group 30. The half-lens 421 is obliquely disposed below the lens group 30 and optically coupled to the lens group 30. There is an angle θ between a reflective surface of the half-lens 421 and the light ray 11 to be aligned. The angle θ can be between 25° and 65°, for example, between 40° and 50°. In this embodiment, the angle is 45°. The lens group 30 is used to direct the light beam 11 to be aligned downwards to the semi-transparent lens 421. The light beam 11 is partially reflected from the semi-transparent lens 421 and partially penetrates the semi-transparent lens 421 to form a first beam 60 and a second beam 70 that are transmitted laterally. The first beam 60 and the second beam 70 travel along a first direction and a second direction, respectively. The first direction and the second direction are parallel to each other and opposite to each other.

[0049] The double-sided mirror 41 is disposed in front of the semi-transparent lens 421, and the image capturing assembly 422 is disposed behind the semi-transparent lens 421. The first light beam 60 is transmitted toward the double-sided mirror 41 along the first direction, and the second light beam 70 is transmitted toward the image capturing assembly 422 along the second direction. The double-sided mirror 41 is symmetrically arranged on the work stage 50 with respect to the double-sided mirror 41. The double-sided mirror 41 is located between the two symmetrical optical alignment devices 42, and there is a gap d between the double-sided mirror 41 and the semi-transparent lens 421 in the two optical alignment devices 42.

[0050] The double-sided reflector 41 is vertically positioned, and each side of the double-sided reflector 41 has a first vertical reflecting surface 411 and a second vertical reflecting surface 412 opposite to the first vertical reflecting surface 411. Please refer to the following section. Figures 2A to 2D The first vertical reflecting surface 411 and the second vertical reflecting surface 412 each have a preset pattern 413, which are corresponding to each other in position. In one example, the preset pattern 413 includes, but is not limited to, an annular shape 413a, a circle 413b, a square shape 413c, or a cross mark 413d. The first vertical reflecting surface 411 and the second vertical reflecting surface 412, which are engraved with the preset pattern 413, are optically coupled to the semi-transparent lens 421.

[0051] The image capturing component 422 is optically coupled to the semi-transparent lens 421 and the double-sided mirror 41 to acquire the images of the second beam 70 and the first beam 60 after reflection by the double-sided mirror 41. In one example, the image capturing component 422 is a charge-coupled device (CCD).

[0052] The light beam 11 to be aligned is emitted by the light source 10, and is guided into the lens group 30 via the mirror group 20. The lens group 30 guides the light beam 11 to be aligned into the semi-transparent lens 421. The semi-transparent lens 421 receives the light beam 11 to be aligned and forms the first beam 60 and the second beam 70, and thus enters the image capturing component 422 for imaging.

[0053] The first vertical reflecting surface 411 and the second vertical reflecting surface 412 of the double-sided reflector 41 each have the preset pattern 413. When the first beam 60 and the second beam 70 enter the image capturing component 422, the preset pattern 413 will be displayed in the image obtained by the image capturing component 422. By determining the position of the preset pattern 413 in the image, it can be determined whether the light path of the light ray 11 to be aligned through the reflector group 20 and the lens group 30 meets the expectation.

[0054] Because the double-sided reflector 41 in this invention is configured vertically, it does not need to be adjusted to match the size of the exposure machine stage or substrate. This allows for a reduction in the size and weight of the double-sided reflector 41, thereby lowering equipment costs.

Claims

1. An optical alignment assembly for an exposure machine, characterized in that, Include: Two optical alignment devices are located at opposite ends of a work stage. These devices are horizontally symmetrically arranged relative to a position to be aligned and each includes: A half-lens, receiving a beam of light from a light source to be aligned and guiding it to a first position and a second position; and An image capturing component is optically coupled to the semi-transparent lens and receives the light to be aligned from the semi-transparent lens from the second position; and A double-sided mirror is vertically disposed at the alignment position on the work platform and has a first vertical reflecting surface and a second vertical reflecting surface opposite to the first vertical reflecting surface, which are optically coupled to the semi-transparent lens respectively. The double-sided mirror has at least one preset pattern and receives the alignment light traveling along the first orientation from the semi-transparent lens. The image captured by the image capturing component shows a reflected light from the double-sided mirror and a preset pattern, which serves as a positioning reference for the light to be aligned.

2. The optical alignment assembly for an exposure machine according to claim 1, characterized in that, The double-sided reflector has a preset pattern on each of its two sides, and the preset patterns overlap along a normal direction of the double-sided reflector.

3. The optical alignment assembly for an exposure machine according to claim 2, characterized in that, The preset patterns include circular, square, or cross symbols.

4. The optical alignment assembly for an exposure machine according to claim 1, characterized in that, The light source is ultraviolet, deep ultraviolet, or super ultraviolet light.

5. The optical alignment assembly for an exposure machine according to claim 1, characterized in that, There is an angle between the light ray to be aligned and a reflecting surface of the semi-transparent lens, and the angle ranges between 25° and 65°.

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