CN116046799A - Dark field lighting device and lighting method - Google Patents
Dark field lighting device and lighting method Download PDFInfo
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- CN116046799A CN116046799A CN202211561885.3A CN202211561885A CN116046799A CN 116046799 A CN116046799 A CN 116046799A CN 202211561885 A CN202211561885 A CN 202211561885A CN 116046799 A CN116046799 A CN 116046799A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/8806—Specially adapted optical and illumination features
Abstract
An object of an embodiment of the present application is to provide a dark field lighting device and a lighting method. The dark field illumination device comprises an imaging device, an illumination device and a reflection device; wherein the lighting device is used for providing a dark field light source; the reflecting device is used for receiving specular reflection light rays of the dark field light source on the sample to be detected and reflecting the specular reflection light rays to the sample to be detected. The embodiment of the application has the following advantages: by arranging the illumination device and the reflection device, illumination with different light intensities on different surface features of the sample to be detected is realized; the dark field illumination mode of the embodiment of the application enables the signal response of the detector to small-size particles in the smooth area to be greatly improved compared with the dark field illumination scheme in the prior art, and therefore the dynamic range of dark field detection of the system and the authenticity of defect identification are improved.
Description
Technical Field
The invention relates to the field of semiconductors, in particular to a dark field lighting device and a lighting method.
Background
Dark-field (DF) imaging refers to imaging by the imaging system by capturing scattered light from the target object, where the specularly reflected light of the illumination beam on the object needs to be outside the entrance pupil of the imaging system.
Based on the optical detection system in the prior art, when the wafer is uniformly illuminated, scattering signal intensities are greatly different in different areas due to the differences of surface morphology, surface roughness, particle size, scratch length and the like, the detector is limited by a limited dynamic range, only particles in a certain size range or surfaces in a certain roughness range can be detected, the detector is saturated due to high-intensity signals exceeding the characteristics of the range, and the low-intensity signals are submerged in noise and cannot be detected.
In addition, under the consistent dark field illumination of different areas of the wafer, when the detector has weak response to small-size particles, the scattering signals of the large-size particles not only enable the corresponding areas of the detector to be overexposed and even overflowed, but also generate a large amount of stray light in the elements of the detection system to cause the other areas of the detector to respond, so that the dynamic range of dark field detection of the system and the authenticity of defect identification are reduced.
Disclosure of Invention
An object of an embodiment of the present application is to provide a dark field lighting device and a lighting method.
The embodiment of the application provides a dark field lighting device, which is characterized by comprising an imaging device, a lighting device and a reflecting device; wherein the lighting device is used for providing a dark field light source; the reflecting device is used for receiving specular reflection light rays of the dark field light source on the sample to be detected and reflecting the specular reflection light rays to the sample to be detected.
According to one embodiment, the dark field lighting device further comprises a motion stage for carrying a sample to be detected for movement.
According to one embodiment, the reflecting means comprises an imaging mirror set and a planar mirror.
The embodiment of the application provides a method for lighting by using the dark field lighting device, wherein the method comprises the following steps:
illuminating light rays of a dark field light source to the surface of a sample to be detected through an illuminating device;
receiving specular reflection light of a dark field light source on a sample to be detected through a reflection device and reflecting the specular reflection light to the sample to be detected;
scattered light signals generated by the dark field light source light rays and the light rays reflected by the reflecting device are collected through the detector.
Compared with the prior art, the embodiment of the application has the following advantages: according to the dark field lighting device, by arranging the lighting device and the reflecting device, lighting with different light intensities on different surface features of a sample to be detected is achieved; in addition, the dark field illumination mode of the embodiment of the application greatly improves the signal response of the detector to small-size particles in the smooth area compared with the dark field illumination scheme in the prior art, so that the dynamic range of dark field detection of the system and the authenticity of defect identification are improved.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the accompanying drawings in which:
fig. 1 shows a schematic structure of a dark field lighting device according to an embodiment of the present application;
FIG. 2 illustrates a schematic diagram of an exemplary dark field lighting device according to an embodiment of the present application;
FIG. 3 illustrates a schematic diagram of an exemplary dark field lighting device according to an embodiment of the present application
Fig. 4 shows a flow chart of a method of illumination using a dark field illumination device according to an embodiment of the present application.
The same or similar reference numbers in the drawings refer to the same or similar parts.
Detailed Description
Before discussing exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart depicts operations as a sequential process, many of the operations can be performed in parallel, concurrently, or at the same time. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figures. The processes may correspond to methods, functions, procedures, subroutines, and the like.
Specific structural and functional details disclosed herein are merely representative and are for purposes of describing exemplary embodiments of the invention. The invention may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
It will be understood that, although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe relationships between units (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.) should be interpreted in a similar manner.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It should also be noted that, in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or the figures may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs
Are all of the same as commonly understood by those of ordinary skill in the art to which the exemplary embodiments pertain 5 Meaning. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
0 Embodiments of the present application are described in further detail below with reference to the accompanying drawings.
Fig. 1 shows a schematic structure of a dark field lighting device according to an embodiment of the present application.
The dark field lighting device according to the embodiment of the application can be used as or contained in defect detection equipment in semiconductor manufacturing process equipment.
The dark field lighting device according to the embodiment of the application comprises an imaging device 101 and a lighting device 5 And 102 reflecting means 103.
The imaging device 101 includes various devices that can be used to obtain optical signals, including, but not limited to, an objective lens, a barrel lens, a camera, combinations thereof, and the like.
Wherein the illumination device 102 is configured to provide a dark field light source, which includes various light sources that provide dark field illumination, such as lasers, LEDs, etc.
0 As shown in fig. 1, an illumination beam emitted from an illumination device 102 is irradiated to the surface of a sample 104 to be detected.
The reflecting device 103 is configured to receive a specularly reflected light beam from the dark field light source on the sample 104 to be detected and reflect the specularly reflected light beam onto the sample to be detected.
Wherein the sample to be detected includes, but is not limited to, a wafer.
5 As shown in fig. 1, the scattered light beam generated by the dark field light source light together with the light reflected by the reflecting means is collected by the detector 105.
According to one embodiment, by means of the illumination means and the reflection means it is achieved that illumination of different light intensities is obtained on different surface features of the wafer.
Specifically, the rough area of the wafer (the rough area can be regarded as a series of large-size particles randomly distributed) scatters the illumination light of the dark field light source into the whole hemisphere, such as lambertian scattering, the light intensity of specular reflection is greatly reduced, and then the detector mainly collects the scattering signal generated by the illumination light of the dark field light source; the smooth area of the wafer mainly generates specular reflection, and specular reflection light rays are reflected to the smooth area by the reflecting device, so that the detector mainly collects scattered signals generated by dark field light source illumination and specular reflection light illumination, and illumination with different intensities of the rough area and the smooth area is realized.
Since the wafer specular reflectivity is about fifty percent in the visible region, the energy utilization of the reflective device of embodiments of the present application may be up to about ninety-nine percent, i.e., the smooth regions of the wafer will achieve about fifty percent higher illuminance than the rough regions. The signal response of the detector to small-size particles in the smooth area of the wafer is improved by about fifty percent compared with the traditional dark field illumination mode in the illumination mode of the embodiment of the application before the scattered signal in the rough area of the wafer reaches saturation and the generated parasitic light is higher than the acceptable threshold value of the system, so that the signal-to-noise ratio and the dynamic range of the system are greatly improved.
According to one embodiment, the dark field lighting device further comprises a motion stage.
The motion platform is used for carrying a sample to be detected to move.
Preferably, when the imaging range of the imaging device is smaller than the size of the sample to be detected, the moving table drives the sample to be detected to move so as to realize detection of the whole wafer.
Fig. 2 shows a schematic structural diagram of an exemplary defect detection apparatus according to an embodiment of the present application.
The various reference numerals in fig. 2 and their corresponding components are represented as follows:
201: a motion stage;
202: laser;
203: a planar mirror;
204: an objective lens;
205: a cylindrical mirror;
206: a detector;
207: and (3) a wafer.
The defect detecting device shown in fig. 2 includes a motion stage 201, a laser 202, a plane mirror 203, an objective lens 204, and a barrel lens 205.
The motion stage 201 is used to drive the wafer to move, so as to realize the detection of the whole wafer.
Wherein the objective lens 204 and the barrel lens 205 constitute a microscopic imaging system. The microscopic imaging system is used to acquire scattered light imaging of the surface of the wafer 207.
Wherein the laser 202 acts as a dark field illumination source.
The laser 202 emits laser light onto the wafer 207 at a specific inclination angle, and the plane mirror 203 receives and reflects the reflected light of the wafer 207.
The detector 206 is used for collecting scattered light signals generated by the light of the laser 202 and the light reflected by the plane mirror 203.
Fig. 3 shows a schematic structural diagram of an exemplary dark field lighting device according to an embodiment of the present application.
The various reference numerals in fig. 3 and their corresponding components are represented as follows:
301: a motion stage;
302：LED；
303: an imaging lens group;
304: a planar mirror;
305: an objective lens;
306: a cylindrical mirror;
307: a detector;
308: and (3) a wafer.
The defect detecting device shown in fig. 3 includes a moving stage 301, an LED302, an imaging lens group 303, a plane mirror 304, an objective lens 305, and a barrel mirror 306.
The motion stage 301 is used to drive the wafer to move, so as to implement the detection of the whole wafer.
Wherein the objective lens 305 and the barrel lens 306 constitute a microscopic imaging system. The microscopic imaging system is used to acquire scattered light imaging of the surface of the wafer 308.
Wherein the LED302 acts as a dark field illumination source.
Wherein the imaging lens group 303 and the plane mirror 304 constitute a reflective optical system.
The LED302 emits the extended light at a specific inclination angle on the wafer 308, and the imaging lens group 303 images the illumination area of the wafer 308 onto the plane mirror 304, and the plane mirror 304 receives and reflects the reflected light of the wafer 308.
The detector 307 is used for collecting scattered light signals generated by the light of the LED302 and the light reflected by the plane mirror 304.
It should be noted that the foregoing examples are only for better illustrating the technical solution of the present invention, and not for limiting the present invention, and those skilled in the art should understand that any implementation of the dark field lighting device according to the embodiments of the present application should be included in the scope of the present invention.
According to the device provided by the embodiment of the application, by arranging the illumination device and the reflection device, illumination with different light intensities on different surface features of the sample to be detected is realized; in addition, the dark field illumination mode of the embodiment of the application greatly improves the signal response of the detector to small-size particles in the smooth area compared with the dark field illumination scheme in the prior art, so that the dynamic range of dark field detection of the system and the authenticity of defect identification are improved.
Fig. 4 shows a flow chart of a method of illumination using a dark field illumination device according to an embodiment of the present application.
Referring to the figure, the method includes step S1, step S2, and step S3.
In step S1, light from a dark field light source is irradiated to the surface of the sample to be detected by an illumination device.
The dark field light source includes various light sources, such as laser, LED, etc., which can provide dark field illumination.
In step S2, the reflecting device receives the specular reflection light of the dark field light source on the sample to be detected and reflects the specular reflection light onto the sample to be detected.
In step S3, the scattered light signal generated by the dark field light source light and the light reflected by the reflecting means together is collected by the detector.
According to an embodiment, the method of the embodiment of the application achieves that illumination with different light intensities is obtained on different surface features of the wafer by means of the illumination device and the reflection device.
Specifically, the rough area of the wafer (the rough area can be regarded as a series of large-size particles randomly distributed) scatters the illumination light of the dark field light source into the whole hemisphere, such as lambertian scattering, the light intensity of specular reflection is greatly reduced, and then the detector mainly collects the scattering signal generated by the illumination light of the dark field light source; the smooth area of the wafer mainly generates specular reflection, and specular reflection light rays are reflected to the smooth area by the reflecting device, so that the detector mainly collects scattered signals generated by dark field light source illumination and specular reflection light illumination, and illumination with different intensities of the rough area and the smooth area is realized.
The illumination method of the embodiment of the present application is described below with reference to examples.
Referring to fig. 2, when the dark field illumination apparatus shown in fig. 2 is used, laser light 202 is emitted onto a wafer 207 at a specific inclination angle in step S1, then reflected light rays of the wafer 207 are received and reflected by a plane mirror 203 in step S2, and then scattered light signals generated by the light rays of the laser light 202 and the light rays reflected by the plane mirror 203 together are collected by a detector 206 in step S3.
Referring to fig. 3, when the dark field illumination apparatus shown in fig. 3 is used, light of the LED302 is irradiated onto the wafer 308 at a specific inclination angle in step S1, then the imaging mirror group 303 images an illumination area of the wafer 308 onto the plane mirror 304 and receives and reflects the reflected light of the wafer 308 through the plane mirror 304, and then a scattered light signal generated by the light of the LED302 and the light reflected through the plane mirror 304 is collected by the detector 307 in step S3.
It should be noted that the foregoing examples are only for better illustrating the technical solution of the present invention, and not for limiting the present invention, and those skilled in the art should understand that any implementation of dark field illumination using the dark field illumination device according to the embodiments of the present application is included in the scope of the present invention.
According to the method, illumination with different light intensities is obtained on different surface features of the sample to be detected; in addition, the dark field illumination mode of the embodiment of the application greatly improves the signal response of the detector to small-size particles in the smooth area compared with the dark field illumination scheme in the prior art, so that the dynamic range of dark field detection of the system and the authenticity of defect identification are improved.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is evident that the word "comprising" does not exclude other elements or steps, and that the singular does not exclude a plurality. A plurality of units or means recited in the system claims can also be implemented by means of software or hardware by means of one unit or means. The terms first, second, etc. are used to denote a name, but not any particular order.
Claims (6)
1. A dark field lighting device, characterized in that the dark field lighting device comprises an imaging device, a lighting device and a reflecting device;
wherein the lighting device is used for providing a dark field light source;
the reflecting device is used for receiving specular reflection light rays of the dark field light source on the sample to be detected and reflecting the specular reflection light rays to the sample to be detected.
2. The dark field lighting device of claim 1, further comprising a motion stage for carrying a sample to be detected for movement.
3. Dark field illumination device according to claim 1 or 2, characterized in that the scattered light signal generated by the dark field illumination light together with the light passing through the reflection means is collected by means of an optical system and a detector.
4. Dark field lighting device according to claim 1 or 2, characterized in that the reflecting means is a planar mirror.
5. Dark field illumination device according to claim 1 or 2, characterized in that the reflecting means comprise an imaging mirror group and a planar mirror.
6. A method of illumination using the dark field illumination device of any one of the preceding claims 1 to 5, wherein the method comprises:
illuminating light rays of a dark field light source to the surface of a sample to be detected through an illuminating device;
receiving specular reflection light of a dark field light source on a sample to be detected through a reflection device and reflecting the specular reflection light to the sample to be detected;
scattered light signals generated by the dark field light source light rays and the light rays reflected by the reflecting device are collected through the detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211561885.3A CN116046799A (en) | 2022-12-07 | 2022-12-07 | Dark field lighting device and lighting method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211561885.3A CN116046799A (en) | 2022-12-07 | 2022-12-07 | Dark field lighting device and lighting method |
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| CN116046799A true CN116046799A (en) | 2023-05-02 |
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| CN202211561885.3A Pending CN116046799A (en) | 2022-12-07 | 2022-12-07 | Dark field lighting device and lighting method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116840260A (en) * | 2023-07-24 | 2023-10-03 | 中国科学院微电子研究所 | Wafer surface defect detection method and device |
| CN116840260B (en) * | 2023-07-24 | 2024-05-10 | 中国科学院微电子研究所 | Wafer surface defect detection method and device |
-
2022
- 2022-12-07 CN CN202211561885.3A patent/CN116046799A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116840260A (en) * | 2023-07-24 | 2023-10-03 | 中国科学院微电子研究所 | Wafer surface defect detection method and device |
| CN116840260B (en) * | 2023-07-24 | 2024-05-10 | 中国科学院微电子研究所 | Wafer surface defect detection method and device |
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