CN-115200519-B - Method and apparatus for virtual focus size detection for objective lens group mounts

CN115200519BCN 115200519 BCN115200519 BCN 115200519BCN-115200519-B

Abstract

The application provides a method and a device for detecting virtual focus size of an objective lens mounting seat, wherein the method comprises the steps of constructing a three-dimensional orthogonal reference plane through three-dimensional equipment according to measured machining and mounting references of the objective lens mounting seat, establishing a Cartesian coordinate system based on the three-dimensional orthogonal reference plane, measuring three-dimensional size data of two objective lens mounting holes on the objective lens mounting seat through the three-dimensional equipment, constructing two axes corresponding to the two objective lens mounting holes respectively according to the three-dimensional size data, constructing a focal plane, wherein the focal plane is parallel to a Top plane in the three-dimensional orthogonal reference plane, judging whether two intersection points formed between the two axes and the focal plane are all located in a virtual sphere taking a point where the focal plane and the Cartesian coordinate system axis intersect as a center, and if so, determining that the objective lens mounting seat is qualified. The application facilitates the use of a qualified objective lens mount to an optical system.

Inventors

LU YANGYANG
LI YU
LIU JUNKAI

Assignees

睿励科学仪器（上海）有限公司

Dates

Publication Date: 20260508
Application Date: 20210408

Claims (10)

1.A method for virtual focus size detection of an objective lens mount, wherein the method comprises: according to the measured machining and installation references of the objective lens group installation seat, a three-dimensional orthogonal reference plane is constructed through three-dimensional coordinate equipment, and a Cartesian coordinate system is established based on the three-dimensional orthogonal reference plane; measuring three-dimensional size data of two objective lens mounting holes on the objective lens group mounting seat through the three-dimensional equipment, and constructing two axes corresponding to the two objective lens mounting holes respectively according to the three-dimensional size data; constructing a focal plane, wherein the focal plane is parallel to a Top plane in the three-dimensional orthogonal reference plane; Judging whether two intersection points formed between the two axes and the focal plane are all positioned in a virtual small sphere taking a point where the focal plane and the Cartesian coordinate system axis intersect as a center, if so, determining that the objective lens group mounting seat is qualified; And if the two intersection points are not all located in the virtual small sphere, translating the focal plane within the tolerance range of the focal plane to obtain new two intersection points, judging whether the new two intersection points are located in the virtual small sphere which takes the intersection point of the focal plane and the Cartesian coordinate system axis as the center, if so, determining that the objective lens group mounting seat is qualified, otherwise, executing the translation operation and the judgment operation again until the objective lens group mounting seat is determined to be qualified or the focal plane is moved within the tolerance range to be ended.
2. The method of claim 1, wherein the determining whether both of the two intersection points formed between the two axes and the focal plane are located within a virtual sphere centered on a point where the focal plane and the cartesian coordinate system axis intersect, if so, determining that the objective mount is acceptable comprises: Obtaining three-dimensional coordinates of two intersections formed between the two axes and the focal plane; taking a point at which the focal plane and the Cartesian coordinate system axis intersect as a coordinate origin, and calculating the distance between each intersection point of the two intersection points and the coordinate origin according to the three-dimensional coordinates; And judging whether the distance between each intersection point and the coordinate origin is smaller than the radius of a virtual small sphere taking the coordinate origin as the center, and if so, determining that the objective lens group mounting seat is qualified.
3. The method of claim 1, wherein the constructing a focal plane comprises: and judging whether the included angle between the two axes and the three-dimensional orthogonal reference plane meets the design requirement, if so, constructing a focal plane, otherwise, determining that the objective lens group mounting seat is unqualified and finishing detection.
4. A method according to any one of claims 1 to 3, wherein the stylus of the three-coordinate device is a ruby sphere and the measurement accuracy is of the sub-micron order.
5. An apparatus for virtual focus size detection of an objective lens group mount, wherein the apparatus comprises: the first module is used for constructing a three-dimensional orthogonal reference plane through three-dimensional equipment according to the measured machining and installation references of the objective lens group installation seat, and establishing a Cartesian coordinate system based on the three-dimensional orthogonal reference plane; the second module is used for measuring three-dimensional size data of two objective lens mounting holes on the objective lens group mounting seat through the three-dimensional equipment and constructing two axes corresponding to the two objective lens mounting holes respectively according to the three-dimensional size data; A third module for constructing a focal plane, wherein the focal plane is parallel to a Top plane in the three-dimensional orthogonal reference plane; A fourth module for judging whether two intersection points formed between the two axes and the focal plane are all located in a virtual sphere which takes a point where the focal plane and the Cartesian coordinate system axis intersect as a center, if so, determining that the objective lens group mounting seat is qualified; wherein the device is further for: And if the two intersection points are not all located in the virtual small sphere, translating the focal plane within the tolerance range of the focal plane to obtain new two intersection points, judging whether the new two intersection points are located in the virtual small sphere which takes the intersection point of the focal plane and the Cartesian coordinate system axis as the center, if so, determining that the objective lens group mounting seat is qualified, otherwise, executing the translation operation and the judgment operation again until the objective lens group mounting seat is determined to be qualified or the focal plane is moved within the tolerance range to be ended.
6. The apparatus of claim 5, wherein the fourth module is to: Obtaining three-dimensional coordinates of two intersections formed between the two axes and the focal plane; taking a point at which the focal plane and the Cartesian coordinate system axis intersect as a coordinate origin, and calculating the distance between each intersection point of the two intersection points and the coordinate origin according to the three-dimensional coordinates; And judging whether the distance between each intersection point and the coordinate origin is smaller than the radius of a virtual small sphere taking the coordinate origin as the center, and if so, determining that the objective lens group mounting seat is qualified.
7. The apparatus of claim 5, wherein the third module is to: and judging whether the included angle between the two axes and the three-dimensional orthogonal reference plane meets the design requirement, if so, constructing a focal plane, otherwise, determining that the objective lens group mounting seat is unqualified and finishing detection.
8. The apparatus of any one of claims 5 to 7, wherein the stylus of the three-coordinate device is a ruby sphere and the measurement accuracy is of the sub-micron order.
9. A computer device, wherein the computer device comprises: a memory for storing one or more programs; one or more processors, coupled to the memory, The one or more programs, when executed by the one or more processors, cause the one or more processors to perform the method of any of claims 1-4.
10. A computer readable storage medium having stored thereon a computer program executable by a processor to perform the method of any of claims 1 to 4.

Description

Method and apparatus for virtual focus size detection for objective lens group mounts Technical Field The application relates to the field of wafer film measurement and optical nondestructive detection in the semiconductor industry, in particular to a technical scheme for detecting the virtual focus size of an objective lens group mounting seat for mounting an objective lens in pairs. Background The importance of the film detection of the wafer in the semiconductor industry as one of a plurality of procedures in the semiconductor manufacturing process is undoubtedly that the film thickness detection is carried out by using elliptical polarized light, and the method is an optical detection method without damaging the surface of the wafer. In the optical detection system, an incident objective lens and an emergent objective lens are arranged in pairs for incidence of polarized light, the polarized light is reflected by a wafer after focusing, and the reflected light is changed into parallel light through the emergent objective lens, and then is sent to a signal receiver through a depolarizer. The objective lens is installed, adjusted and the light path is adjusted separately, and a part of the objective lens is installed on a mechanical piece, namely an objective lens installation seat, and whether the size of the hole for installing the objective lens on the objective lens installation seat reaches the design tolerance is an important basis for judging whether the objective lens installation seat is qualified or not. When the objective lens is used in pairs, under the condition that the two objective lenses are in clearance fit with the mounting seats of the two objective lenses with very small tolerance, besides the form and position tolerance of a single objective lens mounting hole on the mounting seat of the objective lens group, the most important is that the position relation of the two objective lens mounting holes on the mounting seat of the objective lens group needs to be determined, and the key index reflecting the position relation is the virtual space focus of the objective lens determined by the two holes. However, in the conventional detection means, a method of direct measurement is lacking for the detection of the high-precision virtual space focus, and in the conventional detection means, it is necessary to determine a plurality of sizes respectively, and it is impossible to directly determine whether the precision of the part can meet the design requirement. Disclosure of Invention The application aims to provide a technical scheme for detecting the size of a virtual focus of an objective lens group mounting seat, which is beneficial to determining a qualified objective lens group mounting seat for an optical system by determining the size of the virtual focus of the objective lens group mounting seat in space by adopting a three-coordinate measurement technology, so that the performance and the adjustment success rate of the optical system can be improved. According to an aspect of the present application, there is provided a method for virtual focus size detection of an objective lens group mount, wherein the method comprises: according to the measured machining and installation references of the objective lens group installation seat, a three-dimensional orthogonal reference plane is constructed through three-dimensional coordinate equipment, and a Cartesian coordinate system is established based on the three-dimensional orthogonal reference plane; measuring three-dimensional size data of two objective lens mounting holes on the objective lens group mounting seat through the three-dimensional equipment, and constructing two axes corresponding to the two objective lens mounting holes respectively according to the three-dimensional size data; constructing a focal plane, wherein the focal plane is parallel to a Top plane in the three-dimensional orthogonal reference plane; And judging whether two intersection points formed between the two axes and the focal plane are all positioned in a virtual small sphere taking a point where the focal plane and the Cartesian coordinate system axis intersect as a center, and if so, determining that the objective lens group mounting seat is qualified. According to another aspect of the present application, there is provided an apparatus for virtual focus size detection of an objective lens group mount, wherein the apparatus comprises: the first module is used for constructing a three-dimensional orthogonal reference plane through three-dimensional equipment according to the measured machining and installation references of the objective lens group installation seat, and establishing a Cartesian coordinate system based on the three-dimensional orthogonal reference plane; the second module is used for measuring three-dimensional size data of two objective lens mounting holes on the objective lens group mounting seat through the three-dimensional equipment a