A micro-drive focusing alignment device

Abstract

This invention provides a micro-driven focusing alignment device, belonging to the alignment technology of semiconductor optical quantity detection. The alignment device includes an alignment illumination light group, a coupling light group, and an alignment imaging light group disposed in the alignment housing. The light emitted from the alignment illumination light group is transmitted into the coupling light group to provide illumination light, and the light from the coupling light group is reflected into the alignment imaging light group to provide image information of the target object. The coupling light group uses a variable-pitch micro-driver to assist focusing. All optical paths in this application are on the same plane, with a simple layout and easy implementation. The coupling light group uses a variable-pitch micro-driver to drive the acquisition objective lens to assist focusing, improving pre-alignment accuracy and speed. It is convenient for widespread application in nanoscale quantity detection scenarios such as semiconductor overlay alignment, CD, and defect detection.

Description

Technical Field

[0001] This invention relates to alignment technology for semiconductor optical quantity detection, specifically to a micro-drive focusing alignment device. Background Technology

[0002] In the field of semiconductor metrology, optical lens assemblies are typically used to accurately position targets, such as wafers, before metrology or processing. Traditionally, this is achieved using single-target addressing and autofocus via an optical eyepiece, combined with wafer stage movement. This traditional positioning method relies on manual operation and optically assisted alignment marks, which is not only slow but also extremely difficult, failing to meet the current high-precision requirements at the 10+ nanometer level, severely impacting production capacity. Therefore, to meet the needs of current overlay, bright-field, dark-field metrology, and photolithography scenarios, a new target pre-positioning method needs to be designed. Utility Model Content

[0003] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a micro-drive focusing alignment device that can solve the above-mentioned problems.

[0004] A micro-drive focusing alignment device includes an alignment illumination light group, a coupling light group, and an alignment imaging light group disposed in an alignment housing. The light emitted from the alignment illumination light group is transmitted into the coupling light group to provide illumination light, and the light from the coupling light group is reflected into the alignment imaging light group to provide image information of the target object. The coupling light group uses a variable-pitch micro-drive to assist focusing.

[0005] Furthermore, the alignment illumination light group includes an illumination source, an illumination tube mirror, and an illumination reflection unit. The illumination reflection unit reflects the outgoing light from the illumination tube mirror and directs it towards the downstream coupling light group.

[0006] Furthermore, the coupling light group includes a semi-transparent mirror and a collection objective lens; the collection objective lens is driven by a ring-shaped variable-range micro-actuator to achieve rapid fine-tuning of the focus.

[0007] Furthermore, the alignment imaging light group includes an imaging tube lens group and an image acquisition unit. The reflected optics of the semi-transparent mirror of the coupling light group are directed towards the imaging lens group and finally received by the image acquisition unit to form image information.

[0008] Compared with the prior art, the advantages of this utility model are as follows: all optical paths of the device are on the same plane, the layout is simple and easy to implement, the coupling optical group uses a variable pitch micro-driver to drive the acquisition objective lens to assist in focusing, which improves the pre-alignment accuracy and speed; it is convenient to promote and apply in nanoscale quantity detection scenarios such as semiconductor overlay alignment, CD, and defects. Attached Figure Description

[0009] Figure 1 and Figure 2 These are schematic diagrams of the alignment device for micro-drive focusing according to this utility model from different perspectives. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0011] A micro-drive focusing alignment device, see Figure 1 and Figure 2 The alignment device includes an alignment illumination light group, a coupling light group, and an alignment imaging light group disposed in the alignment housing 1. The light emitted from the alignment illumination light group is transmitted into the coupling light group to provide illumination light, and the light from the coupling light group is reflected into the alignment imaging light group to provide image information of the target object. The coupling light group uses a variable-pitch micro-driver 7 to assist in focusing.

[0012] The alignment illumination light group includes an illumination source 2, an illumination tube mirror 3, and an illumination reflection unit 4. The illumination reflection unit 4 reflects the light emitted from the illumination tube mirror 3 and directs it to the downstream coupling light group.

[0013] The illumination source 2 uses an area array camera. The homogenizing lens group of the illumination tube lens 3 is fixed to the inner wall of the alignment housing 1 by a lens tube.

[0014] The coupling light group includes a semi-transparent mirror 5 and a collection objective lens 6. The collection objective lens 6 is driven by a ring-shaped variable-range micro-actuator 7, enabling rapid fine-tuning of the focus. In this specific example, the variable-range micro-actuator 7 is a piezoelectric displacement actuator.

[0015] The alignment imaging light group includes an imaging tube lens group 8 and an image acquisition unit 9. The reflected optics of the semi-transparent mirror 5 of the coupling light group are directed towards the imaging lens group 8 and finally received by the image acquisition unit 9 to form image information.

[0016] The alignment housing 1 is divided into a light source chamber and an optical path chamber by a light shield 10. The illumination source 2, the illumination tube mirror 3 and the illumination reflection unit 4 are located in the light source chamber, while the semi-transparent and semi-reflective mirror 5, the imaging mirror group 8 and the image acquisition device 9 are located in the optical path chamber.

[0017] In the illustrated example, the alignment housing 1 is divided into a light source chamber and an optical path chamber by a light shield 10. The housing shown in the illustration has its cover removed; in reality, the alignment housing 1 is a relatively enclosed dark chamber.

[0018] The coupled light group also includes an angle adjuster 11 for adjusting the angle of the semi-transparent mirror 5. Similarly, an angle adjuster can also be provided at the illumination reflection unit 4.

[0019] The optical paths of this application are arranged in the same plane, that is, the optical paths of the alignment illumination light group, the coupling light group, and the alignment imaging light group are in the same plane, as shown in the figure. Figure 2 The paper is parallel to the plane. Therefore, it can capture images of objects on a platform perpendicular to this plane.

[0020] Currently, this device has been applied to metrology equipment for overlay alignment as well as CD and defect metrology equipment for bright and dark fields in the front-end of wafer fabrication.

[0021] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A micro-drive focusing alignment device, characterized in that: The alignment device includes an alignment illumination light group, a coupling light group and an alignment imaging light group disposed in the alignment housing (1). The light emitted from the alignment illumination light group is transmitted into the coupling light group to provide illumination light, and the light from the coupling light group is reflected into the alignment imaging light group to provide image information of the target object. The coupling light group uses a variable pitch micro-driver (7) to assist in focusing.

2. The alignment device according to claim 1, characterized in that: The aligned illumination light group includes an illumination source (2), an illumination tube mirror (3), and an illumination reflection unit (4). The illumination reflection unit (4) reflects the outgoing light from the illumination tube mirror (3) and directs it to the downstream coupling light group.

3. The alignment device according to claim 2, characterized in that: The coupling light group includes a semi-transparent mirror (5) and a collection objective (6); the collection objective (6) is driven by a ring-shaped variable-range micro-actuator (7) to achieve rapid fine adjustment of the focal length.

4. The alignment device according to claim 3, characterized in that: The alignment imaging light group includes an imaging tube lens group (8) and an image acquisition unit (9). The reflected optics of the semi-transparent mirror (5) of the coupling light group are directed to the imaging lens group (8) and finally received by the image acquisition unit (9) to form image information.

5. The alignment device according to claim 4, characterized in that: The alignment housing (1) is divided into a light source chamber and an optical path chamber by a light shield (10). The illumination light source (2), illumination tube mirror (3) and illumination reflection unit (4) are located in the light source chamber, while the semi-transparent mirror (5), imaging mirror group (8) and image acquisition device (9) are located in the optical path chamber.

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