A beam scanning stage for object mirror quality detection

Abstract

The present invention discloses a beam scanning stage for objective lens quality detection, which is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle. The beam scanning stage includes an XYZ electric moving stage, a beam mirror group, and a condenser lens. The XYZ electric translation stage can achieve high-precision positioning movement of the condenser lens in three degrees of freedom, enabling the condenser lens to perform scanning movement in the XY directions along the mask plate containing the pinhole array; the beam mirror group consists of two mirrors, which are respectively installed on the X movement layer and the Y movement layer of the electric moving stage, and move along the X and Y directions respectively following the electric moving stage, and can introduce the objective lens quality detection light source into the condenser lens group. The condenser lens is installed on the XYZ electric moving stage, converges the objective lens quality detection light source into a point light source, and irradiates it onto the mask plate.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic special equipment, and particularly relates to a beam scanning stage for objective lens quality detection, which is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle. Background Art

[0002] The lithography process is an important step in the semiconductor device manufacturing process. In this step, geometric graphic structures are engraved on the photoresist layer by exposure and development, and then the patterns on the mask are transferred layer by layer to the substrate through the etching process. Finally, dozens of complex circuit structures are formed on the silicon wafer. The imaging quality of the objective lens directly affects the quality of the lithography pattern and overlay, so the image quality detection of the objective lens is particularly important. The Shack-Hartmann wavefront sensor is one of the sensors for objective lens image quality detection based on wavefront detection technology, and is a sensor for measuring the wave aberration and distortion of the objective lens. The beam scanning stage is one of the modules for cooperating with the Hartmann to detect the image quality of the objective lens. It combines with the mask stage and the precision workpiece stage carrying the Hartmann sensor to detect the image quality of the objective lens. Summary of the Invention

[0003] The purpose of the present invention is to provide a beam scanning stage for objective lens quality detection, which is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle. It combines with the mask stage, the precision workpiece stage carrying the Hartmann sensor and the environmental control system to form an objective lens quality detection test stage, which can detect the image quality of the objective lens.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A beam scanning stage for objective lens quality detection, which is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle, includes an XYZ electric moving stage, a beam mirror group and a condenser lens. The XYZ electric translation stage can realize the high-precision positioning movement of the condenser lens in three degrees of freedom, so that the condenser lens can perform XY-direction scanning movement along the mask plate containing the pinhole array; the beam mirror group consists of two mirrors, which are respectively installed on the X movement layer and the Y movement layer of the XYZ electric moving stage, and respectively move along the X and Y directions following the XYZ electric moving stage to introduce the objective lens quality detection light source into the condenser lens. The condenser lens is installed on the XYZ electric moving stage, and converges the objective lens quality detection light source into a point light source and irradiates it onto the mask plate.

[0006] Further, the XYZ electric mobile stage is composed of a Y moving module, a Y displacement measurement sensor, an X moving module, an X displacement measurement sensor, a Z manual displacement stage, a Y guide rail, a Z piezoelectric stage, and a condenser lens barrel. The Y moving module consists of a motor, a lead screw, and a guide rail, and together with the Y guide rail, it forms a driving and executing mechanism for Y-direction movement; the Y displacement measurement sensor measures the displacement in the Y direction in real time and feeds the Y-direction displacement value back to the motor controller to achieve high-precision closed-loop linear movement in the Y direction; the X moving module is installed on the upper layer of the Y moving module and consists of a motor, a lead screw, and a guide rail, which is a driving and executing mechanism for X-direction movement; the X displacement measurement sensor measures the displacement in the X direction in real time and feeds the X-direction displacement value back to the motor controller to achieve high-precision closed-loop linear movement in the X direction; the Z manual displacement stage is installed on the X moving module to achieve coarse adjustment of the focal plane of the condenser lens; the Z piezoelectric stage is installed on the Z manual displacement stage to achieve nano-level fine adjustment of the focal plane of the condenser lens; the condenser lens barrel is installed below the Z piezoelectric stage and is used to install the condenser lens.

[0007] Further, the beam reflector group is composed of a Y reflector, a Y reflector adjustment bracket, an X reflector, and an X reflector adjustment bracket. The Y reflector is installed on the Y reflector adjustment bracket, and the Y reflector adjustment bracket can adjust the angle of the Y reflector, which is used to adjust the beam direction during module integration; the X reflector is installed on the X reflector adjustment bracket, and the X reflector adjustment bracket can adjust the angle of the X reflector, which is used to adjust the beam direction during module integration; the Y reflector adjustment bracket is installed on the Y motion layer of the XYZ electric mobile stage and can move linearly in the Y direction following the XYZ mobile stage; the X reflector adjustment bracket is installed on the X motion layer of the XYZ electric mobile stage and can move linearly in the X and Y directions following the XYZ mobile stage.

[0008] Further, the condenser lens is installed in the condenser lens barrel, and its optical axis coincides with the axis of the condenser lens barrel, and it can move in three degrees of freedom of XYZ following the XYZ electric mobile stage.

[0009] The advantages of the present invention are as follows:

[0010] (1) The present invention is a beam scanning stage for objective lens quality detection and is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle. The pinhole arrays on the Hartmann wavefront measurement mask are all micron-level small holes. The present invention can achieve sub-micron-level horizontal step positioning movement and nano-level focusing movement of the condenser lens, and can accurately pass the point light source passing through the condenser lens through the small holes and be received by the Hartmann sensor installed on the workpiece table through the objective lens.

[0011] (2) Since the Hartmann test light source of the objective lens test bench is introduced from the periphery of the whole machine, but the excessive length of the optical fiber will affect the transmission quality of the light source, so the length of the optical fiber is usually limited and it is not suitable to directly introduce the light source into the condenser through the optical fiber and make a horizontal stepping movement with the condenser. The present invention can realize that no matter the condenser moves in the X direction or the Y direction, the object image quality detection light source can enter the condenser through the Y mirror and the X mirror, converge the object image quality detection light source into a point light source, and irradiate it onto the mask plate. Brief Description of the Drawings

[0012] Figure 1 It is the overall structure diagram of a beam scanning table for object image quality detection according to the present invention. In the figure, 100 - XYZ electric moving table; 200 - beam mirror group; 300 - condenser.

[0013] Figure 2 It is the structure diagram of the XYZ electric moving table. In the figure, 101 - Y moving module, 102 - Y displacement measurement sensor, 103 - X moving module, 104 - X displacement measurement sensor, 105 - Z manual displacement table, 106 - Y guide rail, 107 - Z piezoelectric stage, 108 - condenser barrel.

[0014] Figure 3 It is the structure diagram of the beam mirror group. In the figure, 201 - Y mirror, 202 - Y mirror adjustment bracket, 203 - X mirror, 204 - X mirror adjustment bracket. Detailed Embodiment

[0015] In order to make the features and advantages of the present invention more obvious and understandable, the following will make a detailed description of the specific implementation of the present invention.

[0016] As shown in the Figure 1 drawings, the present invention is a beam scanning table for object image quality detection, which is a sub - module of an object image quality detection table based on the Hartmann wavefront measurement principle, and includes an XYZ electric moving table 100, a beam mirror group 200 and a condenser 300. The XYZ electric translation table 100 can realize the three - degree - of - freedom high - precision positioning movement of the condenser 300, so that the condenser 300 can perform XY - direction scanning movement along the mask plate containing the pinhole array; the beam mirror group 200 is composed of two mirrors, which are respectively installed on the X - motion layer and the Y - motion layer of the XYZ electric moving table 100, and respectively move along the X and Y directions following the XYZ electric moving table 100, and introduce the object image quality detection light source into the condenser 300. The condenser 300 is installed on the XYZ electric moving table 100, converges the object image quality detection light source into a point light source, and irradiates it onto the mask plate.

[0017] As Figure 2As shown in the figure, the XYZ electric mobile stage 100 is composed of a Y moving module 101, a Y displacement measurement sensor 102, an X moving module 103, an X displacement measurement sensor 104, a Z manual displacement stage 105, a Y guide rail 106, a Z piezoelectric stage 107, and a condenser lens barrel 108. The Y moving module 101 is composed of a motor, a lead screw, and a guide rail, and forms a driving and executing mechanism for Y-direction movement with the Y guide rail 106; the Y displacement measurement sensor 102 measures the displacement in the Y direction in real time and feeds the Y-direction displacement value back to the motor controller to achieve high-precision closed-loop linear movement in the Y direction; the X moving module 103 is installed on the upper layer of the Y moving module 101 and is composed of a motor, a lead screw, and a guide rail, which is the driving and executing mechanism for X-direction movement; the X displacement measurement sensor 104 measures the displacement in the X direction in real time and feeds the X-direction displacement value back to the motor controller to achieve high-precision closed-loop linear movement in the X direction; the Z manual displacement stage 105 is installed on the X moving module 103 to achieve rough adjustment of the focal plane of the condenser lens; the Z piezoelectric stage 107 is installed on the Z manual displacement stage 105 to achieve nano-level fine adjustment of the focal plane of the condenser lens; the condenser lens barrel 108 is installed below the Z piezoelectric stage 107 and is used to install the condenser lens 300.

[0018] As Figure 3 shown in the figure, the beam mirror group 200 is composed of a Y mirror 201, a Y mirror adjustment bracket 202, an X mirror 203, and an X mirror adjustment bracket 204. The Y mirror 201 is installed on the Y mirror adjustment bracket 202, and the Y mirror adjustment bracket 202 can adjust the angle of the Y mirror 201, which is used to adjust the beam direction during module integration; the X mirror 203 is installed on the X mirror adjustment bracket 204, and the X mirror adjustment bracket 204 can adjust the angle of the X mirror 203, which is used to adjust the beam direction during module integration; the Y mirror adjustment bracket 202 is installed on the Y moving layer of the XYZ electric mobile stage 100 and can move linearly in the Y direction following the XYZ mobile stage 100; the X mirror adjustment bracket 203 is installed on the X moving layer of the XYZ electric mobile stage 100 and can move linearly in the X and Y directions following the XYZ mobile stage 100.

[0019] As Figure 1 、 2 shown in the figure, the condenser lens 300 is installed in the condenser lens barrel 108, and its optical axis coincides with the axis of the condenser lens barrel 108, and it can move in three degrees of freedom of XYZ following the XYZ electric mobile stage 100.

[0020] When the scanning stage is in use, the XYZ electric moving stage 100 carrying the condenser lens 300 can achieve high-precision XYZ positioning movement, enabling the condenser lens to perform a stepping scanning movement in the XY direction along the mask plate containing the pinhole array; at the same time, since the Y mirror 201 can follow the XYZ electric moving stage 100 to perform a linear movement in the Y direction, and the X mirror 203 can follow the XYZ electric moving stage 100 to perform linear movements in the X and Y directions, in this way, regardless of whether the condenser lens 300 moves in the X direction or the Y direction, the object image quality detection light source can enter the condenser lens 300 through the Y mirror 201 and the X mirror 203, converge the object image quality detection light source into a point light source, and irradiate it onto the mask plate.

[0021] The parts not elaborated in detail in the present invention belong to the well-known technologies in the art.

Claims

1. A beam scanning stage for objective lens quality detection, which is a sub-module of an objective lens quality detection stage based on the Hartmann wavefront measurement principle, and is characterized in that: The beam scanning stage includes an XYZ electric moving stage (100), a beam mirror group (200), and a condenser lens (300); The XYZ electric translation stage (100) is used to achieve high-precision positioning movement of the condenser lens (300) in three degrees of freedom, enabling the condenser lens (300) to perform scanning movement in the XY directions along the mask plate containing the pinhole array; The beam mirror group (200) consists of two mirrors, which are respectively installed on the X motion layer and Y motion layer of the XYZ electric moving stage (100), and move along the X and Y directions following the XYZ electric moving stage (100) respectively to introduce the object image quality detection light source into the condenser lens (300); The condenser lens (300) is installed on the XYZ electric moving stage (100) and is used to converge the object image quality detection light source into a point light source and irradiate it onto the mask plate.

2. The beam scanning stage for object mirror quality detection according to claim 1, characterized in that: The XYZ electric moving stage (100) consists of a Y moving module (101), a Y displacement measurement sensor (102), an X moving module (103), an X displacement measurement sensor (104), a Z manual displacement stage (105), a Y guide rail (106), a Z piezoelectric stage (107), and a condenser lens barrel (108); The Y moving module (101) consists of a motor, a lead screw, and a guide rail, and forms a driving and executing mechanism for Y-direction movement with the Y guide rail (106); The Y displacement measurement sensor (102) is used to measure the displacement in the Y direction in real time, and feedback the Y-direction displacement value to the motor controller to achieve high-precision Y-direction closed-loop linear motion; The X moving module (103) is installed on the upper layer of the Y moving module (101) and consists of a motor, a lead screw, and a guide rail, which is a driving and executing mechanism for X-direction movement; The X displacement measurement sensor (104) is used to measure the displacement in the X direction in real time, and feedback the X-direction displacement value to the motor controller to achieve high-precision X-direction closed-loop linear motion; The Z manual displacement stage (105) is installed on the X moving module (103) to achieve rough adjustment of the focal plane of the condenser lens; The Z piezoelectric stage (107) is installed on the Z manual displacement stage (105) to achieve nano-level fine adjustment of the focal plane of the condenser lens; The condenser lens barrel (108) is installed below the Z piezoelectric stage (107) and is used to install the condenser lens (300).

3. The beam scanning stage for mirror quality detection according to claim 2, wherein: The beam mirror group (200) consists of a Y mirror (201), a Y mirror adjustment bracket (202), an X mirror (203), and an X mirror adjustment bracket (204); The Y mirror (201) is installed on the Y mirror adjustment mount (202). The Y mirror adjustment mount (202) can adjust the angle of the Y mirror (201) for adjusting the beam direction during module integration. The X mirror (203) is installed on the X mirror adjustment mount (204). The X mirror adjustment mount (204) can adjust the angle of the X mirror (203) for adjusting the beam direction during module integration. The Y mirror adjustment mount (202) is installed on the Y motion layer of the XYZ electric moving stage (100) and can perform linear motion in the Y direction following the XYZ moving stage (100). The X mirror adjustment mount (204) is installed on the X motion layer of the XYZ electric moving stage (100) and can perform linear motion in the X and Y directions following the XYZ moving stage (100).

4. A beam scanning stage for object mirror quality detection according to claim 2, characterized in that: The condenser lens (300) is installed in the condenser lens barrel (108), and its optical axis coincides with the axis of the condenser lens barrel (108). It can perform motions with three degrees of freedom in the X, Y, and Z directions following the XYZ electric moving stage (100).

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