Inspection system for detecting defect

Abstract

To provide an inspection system for detecting defects.SOLUTION: An inspection system includes: an imaging device having at least one of camera units 102a, 102b for capturing an image of a board, and a lens unit having at least one light source for generating a coherent light beam applied to a board 108, a first lens that is constituted of a first convergence range for imaging the board and is fixed to at least one of the camera units, and a second lens that is constituted of a second convergence range for imaging a structure layer of the board and is fixed to at least one of the camera units; a processor for extracting first and second defect data from image data generated for the board and the structure layer of the board; and an analysis module for analyzing defect data. The analysis module includes a defect position location sub-module for analyzing first and second defect data and generating defect data set including defect position location information regarding both of the board and the structure layer of the board.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of semiconductors, and more particularly to an inspection system for detecting defects in complementary metal oxide semiconductor (CMOS) image sensors (CIS). [Background technology]

[0002] CMOS sensors are fundamental components in a variety of technological applications, including digital cameras, smartphones, and medical imaging devices. Ensuring flawless operation and manufacturing of CMOS sensors is critical to achieving a high-quality imaging and data collection experience. CMOS sensors are susceptible to defects (e.g., pixel defects, dust particles, and scratches). These defects can degrade image quality and reduce device performance. Traditional inspection methods for CMOS sensors often rely on manual inspection or limited automated systems. However, these methods may overlook subtle defects or fail to provide real-time feedback during the manufacturing process. As a result, there is a pressing need for advanced inspection systems that can comprehensively and efficiently detect defects on CMOS sensors.

[0003] (Patent Document 1) discloses a method and system used to detect surface defects on CMOS chips. The method includes dividing image data into smaller detection blocks, applying a binarization process to each block, and extracting defects based on the binarization results. Then, based on the pixels and size of the defects, the defects are analyzed and the validity is determined. Additional steps include performing edge search, positioning adjustment, and secondary binarization for improved accuracy. The system includes modules for image acquisition, block division, defect extraction, and defect analysis.

[0004] Another (Patent Document 2) discloses a defect inspection method for CMOS image sensors, which includes the steps of collecting a gray card graphic, pre-processing the gray card graphic into a gray scale image, shifting data values ​​to obtain a low level image, calculating the standard deviation of the differential image, and comparing the standard deviation to a preset threshold. If the standard deviation exceeds the preset threshold, this indicates a defect in the lower bits of the CMOS image sensor chip. The method includes consideration of different image formats, color conversion, and specific bit shifting techniques.

[0005] Another (Patent Document 3) discloses a device for detecting surface defects on an image sensor including a fixed support, a first lifting mechanism, a lifting seat, a camera module, a coaxial and lateral light source, and a parallel light source module. The first lifting mechanism lifts the lifting seat and the camera module. The camera module, which is equipped with the coaxial and lateral light sources, captures image information for the image sensor. The parallel light source module surrounds the camera module. By combining the lifting mechanism, the camera module, and various light sources, the device can detect surface defects on the image sensor.

[0006] Current inspection systems are primarily focused on identifying defects located on the exterior surfaces, i.e., top and bottom layers, of CMOS image sensors. Nevertheless, inspection systems face significant limitations when it comes to effectively detecting defects present within the interwoven layers of a CMOS image sensor (commonly referred to as "inter-layer defects"). These inter-layer defects represent a significant problem in semiconductor manufacturing as they can drastically affect the overall functionality, performance, and reliability of the final CMOS image sensor. However, existing inspection systems fail to achieve the ability to identify and accurately locate these hidden defects, which presents a formidable challenge for quality control and assurance in the semiconductor industry. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to develop an inspection system capable of detecting inter-layer defects of a CMOS image sensor (CIS). The inspection system is configurable to detect defects (e.g., particles above the glass layer, particles below the glass layer, and surface defects). The inspection system includes an imaging device having at least one camera unit coupled to various lenses of different magnifications. One or more light sources are positioned coaxially with the lens and the camera unit. The first camera unit is configured with a standard magnification lens to capture the entire defect on the CIS unit. After capturing the image by the first imaging device, the CIS unit is moved to a second camera unit configured with a high magnification lens. Advantageously, the configuration of two camera units with variable focal length lenses allows the camera units to focus on a specific layer of the CIS unit, and thus the system can accurately determine the location and position of the inter-layer defect. [Means for solving the problem]

[0008] In one aspect of the present invention, an inspection system for detecting defects is provided, the inspection system including an imaging device configured to image a substrate, the imaging device having at least one camera unit configured to capture an image of the substrate, at least one light source generating a coherent light beam that illuminates the substrate, one or more lens units arranged along an optical path of the camera units to provide a focal range for imaging the substrate, the lens unit having a first lens fixed to at least one of the camera units configured with a first focal range for imaging the substrate and a second lens fixed to at least one of the camera units configured with a second focal range for imaging a constituent layer of the substrate, a processor configured to extract first and second defect data from image data generated for the substrate and the constituent layer of the substrate, and an analysis module configured to analyze the defect data, the analysis module includes a defect location submodule that analyzes the first and second defect data and generates a defect data set including defect location information for both the substrate and the constituent layer of the substrate.

[0009] Preferably, the first defect data and the second defect data include defect information relating to both the substrate and a constituent layer of the substrate.

[0010] Preferably, the first focal range is larger than the second focal range to image both the substrate and a constituent layer of the substrate.

[0011] Preferably, the one or more light sources are positioned between the lens unit and the substrate, with at least one light source positioned laterally relative to the body of the at least one lens unit.

[0012] Preferably, the inspection system further includes a database for logging data, the database logging one or more data sets including the image data, the defect data, and the deposition defect data set.

[0013] Preferably, the inspection system further includes an output module having a user interface configured to display the defect-location information.

[0014] In another aspect of the invention, a method of detecting defects by an inspection system is provided, comprising: imaging the substrate by an imaging device having at least one camera unit configured to capture an image of the substrate, at least one light source generating a coherent light beam that illuminates the substrate, and one or more lens units arranged along optical paths of the camera units to provide a focal range for imaging the substrate, the lens unit having a first lens fixed to at least one of the camera units configured with a first focal range for imaging the substrate and a second lens fixed to at least one of the camera units configured with a second focal range for imaging a constituent layer of the substrate, processing by a processor to extract first and second defect data from image data generated for the substrate and the constituent layer of the substrate, and analyzing the defect data by an analysis module. The analysis module includes a defect location sub-module that analyzes the first and second defect data and generates a defect dataset including defect location information for both the substrate and the constituent layer of the substrate.

[0015] Preferably, the method further comprises the step of transporting the substrate between the camera units by a conveyor for imaging.

[0016] Preferably, the method further comprises storing one or more data sets in a database, the data set comprising the image data, the defect data and the deposition defect data set.

[0017] Preferably, the method further comprises displaying the defect location information relating to both the substrate and the constituent layers of the substrate by an output module, the output module including a user interface for displaying this information. [Brief description of the drawings]

[0018] [Figure 1] 1 illustrates an example of an inspection system according to an embodiment of the present invention. [Diagram 2] FIG. 1 shows a block diagram of an inspection system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be described below according to the preferred embodiment of the present invention by referring to the attached specification and drawings. However, it is understood that the specification is limited to the preferred embodiment of the present invention only for the purpose of facilitating the description of the present invention, and that those skilled in the art can devise various modifications without departing from the scope of the appended claims.

[0020] 1 shows an example of an inspection system according to an embodiment of the present invention. The inspection system according to the present invention includes an imaging device 100 configured to capture an image of a substrate 108. Preferably, the substrate 108 to be imaged is a complementary metal oxide semiconductor (CMOS) imaging sensor or any multi-layer imaging sensor, such as, but not limited to, a charge-coupled device (CCD), a back-illuminated sensor (BIS), a back-illuminated sensor (BSI), and a stacked CMOS sensor. The imaging device 100 includes at least one camera unit 102a, 102b configured to capture an image of the substrate 108, at least one light source generating a coherent light beam to illuminate the substrate, and one or more lens units arranged along the optical path of the camera units 102a, 102b to provide a focused range for imaging the substrate 108.

[0021] Preferably, the camera units 102a, 102b are fixedly mounted to a robot arm and positioned vertically above the substrate 108 to capture images of the substrate 108. Alternatively, at least one of the camera units 102a, 102b is mounted to a robot arm configured with different degrees of freedom to capture images of the substrate 108 at different angles. Preferably, the detectors of the camera units 102a, 102b are CCD or photodiode detectors.

[0022] The light source can be any type of coherent light source, such as, but not limited to, a laser, LED, or arc lamp. It is important to note that the light source is coherent so that the light beams are in phase with each other. Preferably, one or more light sources are positioned between the lens and the substrate 108, as shown in FIG. 1 by light sources 106c, 106d. Additionally, multiple light sources may be positioned coaxially along the optical path of the camera units 102a, 102b to illuminate the substrate 108, as shown in FIG. 1, with light source 106b positioned directly above light source 106d. Alternatively, at least one light source is positioned laterally relative to the body of at least one lens unit, as shown in FIG. 1, and light source 106a is positioned around the lens unit. In an alternative embodiment, the light sources can be offset to one side of the substrate 108 and positioned laterally relative to the optical path of the camera units 102a, 102b to illuminate the substrate 108. Optimally, the light sources for the various embodiments are positioned close to the substrate 108 for uniform illumination. Preferably, one or more lens units are positioned directly above the substrate 108 to focus the resulting coherent light beam onto the substrate 108.

[0023] The lens unit includes a first lens 104a fixed to at least one of the camera units 102a, 102b configured with a first focal range for imaging the substrate 108, and a second lens 104b fixed to at least one of the camera units 102a, 102b configured with a second focal range for imaging the constituent layers of the substrate 108, the first focal range being larger than the second focal range for imaging both the substrate 108 and the constituent layers of the substrate 108. The first lens 104a is configured to image the overall defects and defect locations for the substrate 108 and the constituent layers of the substrate 108, and the second lens 104b is configured to image the defects for the constituent layers of the substrate 108. As an example, the first lens 104a is a standard magnification lens that can include multiple converging lenses arranged in series far from each other and thus having a larger focal range for imaging the substrate 108 with a wider depth of field. In contrast, the second lens 104b is a high magnification lens that may include multiple converging lenses arranged in series close to each other and therefore with a shorter focal range that images the substrate 108 with a narrower depth of field. Preferably, the first lens 104a with a wider depth of field is coupled to the camera unit 102a that captures an image of the substrate 108 including the entire defect, while the second lens 104b with a narrower depth of field is coupled to the camera unit 102b and configured to capture an image of a constituent layer of the substrate 108 including the defects of the constituent layer.

[0024] The inspection system further includes a processor 200 having an image processing sub-module 200a configured to process the raw image obtained via the imaging device 100 by using a computational algorithm to generate image data for both the substrate 108 and the constituent layers of the substrate 108. Optimally, the processor 200 performs an initial adjustment (e.g., correcting any lens distortion, removing sensor noise, and aligning the image before processing the raw image). The processor 200 is configured to extract first and second defect data from the image data generated for the substrate 108 and the constituent layers of the substrate 108, the first and second defect data including defect information related to both the substrate 108 and the constituent layers of the substrate 108. As an example, the first defect data includes defect information of the entire substrate 108, while the second defect data includes defect information of the constituent layers of the substrate 108. Preferably, the processor 200 includes a defect detection sub-module 200b to identify a particular region of interest in the image and extract the first and second defect data.

[0025] The inspection system further includes an analysis module 300 configured to analyze the defect data, the analysis module 300 including a defect location sub-module 300a configured to analyze the first defect data and the second defect data and generate a defect data set including defect location information for both the substrate 108 and the constituent layers of the substrate 108. The analysis module 300 identifies common features in the first defect data and the second defect data and generates the defect data set. In a preferred embodiment, the common features include, but are not limited to, the size, shape, and location of the defects captured by the imaging device 100. The first defect data includes the location and associated attributes of the defects with respect to the top and bottom surfaces of the substrate 108 and the constituent layers of the substrate 108. The second defect data includes the location and associated attributes of the defects with respect to the constituent layers of the substrate 108. The analysis module 300 analyzes both data referencing the location of the defects with respect to the surfaces and constituent layers of the substrate 108 as common features to determine the location of the defects with respect to the substrate 108. More specifically, the defect data set enables the inspection system to identify and precisely locate the location of the defects with respect to the constituent layers of the substrate 108.

[0026] Additionally, the inspection system includes a database 400 for data logging one or more data sets including image data, defect data, and defect data sets. The database 400 may be a local storage device, such as, but not limited to, a hard disk drive (HDD), an internal memory chip, a solid state drive (SSD), a secure digital (SD) card, etc. The data may be stored wirelessly, such as, but not limited to, a cloud server accessible via electronic devices, such as, but not limited to, a computer, a mobile device, etc. Additionally, the database 400 may store program files for application software of the inspection system, including input parameters for inspection of the substrate 108. The processor 200 may be configured to execute software instructions or computer logic instructions based on the application software to initiate inspection of the substrate 108.

[0027] The defect location information stored in the database 400 may be visually presented by an output module 500 having a user interface. Preferably, the user interface is a platform integrated with the inspection system that may include a display controllable via a touch screen or human machine interface (HMI) to register inputs for communication with the inspection system. An image of the substrate 108 showing the location of the defects with respect to the constituent layers may be visually presented on the display, and further, the image may be magnified by a user to facilitate tagging or marking of the defects.

[0028] Below is a description of a method for detecting defects with an inspection system. The steps described are not limiting and minor modifications (i.e., additions, omissions, or substitutions) of the steps are acceptable to those of ordinary skill in the art without significantly departing from what is described.

[0029] The method begins with loading the substrate 108 into an inspection system. Next, the method includes imaging with an imaging device 100 having at least one camera unit 102a, 102b configured to capture an image of the substrate 108, at least one light source generating a coherent light beam to illuminate the substrate 108, and one or more lens units arranged along the optical paths of the camera units 102a, 102b to provide a focal range for imaging the substrate 108, the lens units including a first lens 104a fixed to at least one of the camera units 102a configured with a first focal range for imaging the substrate 108 and a second lens 104b fixed to at least one of the camera units 102a, 102b configured with a second focal range for imaging a constituent layer of the substrate 108. The step of transferring the substrate 108 by the transfer body 110 for the purpose of the present invention is carried out.

[0030] First, the transporter 110 transports the substrate 108 for a first imaging under the camera unit 102a to which a first lens 104a is fixed, configured with a wider depth of field to capture an image of the entire defect of the substrate 108. Upon detection of a defect by the camera unit 102a, the method proceeds with the step of transporting the substrate 108 for a second imaging under the camera unit 102b to which a second lens 104b is fixed, configured with a narrower depth of field to capture an image of the defect of the constituent layer.

[0031] The method then proceeds with processing by the processor 200 generating image data for both the substrate 108 and the constituent layers of the substrate 108 via the image processing sub-module 200a. The processor 200 then proceeds with extracting first and second defect data from the image data generated for the substrate 108 and the constituent layers of the substrate 108 via the defect detection sub-module 200b.

[0032] There is then a step of analyzing the defect data by analysis module 300, which includes a defect location sub-module 300a that analyzes the first defect data and the second defect data and generates a defect data set that includes defect location information for both substrate 108 and constituent layers of substrate 108. The defect location information includes precise locations of the defects with respect to the constituent layers of substrate 108.

[0033] The method then continues with storing the one or more data sets, including the image data, the defect data, and the defect data set, in database 400. Finally, displaying the defect localization information for both substrate 108 and the constituent layers of substrate 108 via output module 500. Output module 500 includes a user interface for displaying this information.

[0034] It should be expressly understood that in the context of this application, terms conveying orientation and positional references anticipated in the illustrations given in the associated drawings (e.g., "up", "down", or similar expressions) are used solely for the purpose of facilitating the description of the invention and streamlining the description. These terms are not intended to inherently limit the relevant devices or components to any particular orientation, or to prescribe or infer that these devices or components must be exclusively conceived, constructed, or utilized in such a manner. It is therefore essential to emphasize that the use of such terms does not impose limitations on the scope and applicability of this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or as an indication of the number of technical features presented. Thus, a feature given as "first" or "second" can explicitly or implicitly include at least one of the features.

[0036] This disclosure includes the subject matter contained in the appended claims and the above specification. Although the invention has been described in a preferred form with some detail, it is understood that the disclosure of the preferred form is made by way of example only, and that many changes in details of construction and in the combination and arrangement of parts may be adopted without departing from the scope of the invention. [Explanation of symbols]

[0037] 100 Imaging Device 102a, 102b Camera unit 104a First lens 104b Second lens 106a, 106b, 106c, 106d light source 108 Substrate 110 Transport 200 processors 200a Image processing sub-module 200b Defect Detection Submodule 300 Analysis Modules 300a Defect Localization Submodule 400 Database 500 Output Module [Prior art documents] [Patent documents]

[0038] [Patent Document 1] Chinese Patent Application Publication No. 114565558A [Patent Document 2] Chinese Patent Application Publication No. 109357687A [Patent Document 3] China Patent Application Publication No. 212410030U

Claims

1. 1. An inspection system for detecting defects, comprising: An imaging device (100) configured to image a substrate (108), comprising: at least one camera unit (102a, 102b) configured to capture an image of the substrate (108); at least one light source generating a light beam that illuminates the substrate (108); one or more lens units disposed along an optical path of the camera units (102a, 102b) to provide a focal range for imaging the substrate (108), a first lens (104a) fixed to at least one of the camera units (102a, 102b), the first lens (104a) configured with a first focal range for imaging the substrate (108); a second lens (104b) fixed to at least one of the camera units (102a, 102b), configured with a second focal range for imaging constituent layers of the substrate (108); A lens unit having An imaging device (100) having a processor (200) configured to extract first and second defect data from image data generated for the substrate (108) and constituent layers of the substrate (108); an analysis module (300) configured to analyze the defect data; Including, the analysis module (300) includes a defect location sub-module (300a) that analyzes the first defect data and the second defect data and generates a defect data set that includes defect location information for both the substrate (108) and constituent layers of the substrate (108). Inspection system.

2. the first defect data and the second defect data include defect information relating to both the substrate (108) and constituent layers of the substrate (108); The inspection system of claim 1 .

3. the first focal range is greater than the second focal range to image both the substrate (108) and constituent layers of the substrate (108); 3. The inspection system according to claim 1 or 2.

4. one or more light sources are positioned between the lens unit and the substrate; The at least one light source is positioned laterally relative to the body of the at least one lens unit. The inspection system according to any one of claims 1 to 3.

5. a database (400) for logging data for logging one or more data sets including the image data, defect data, and defect data sets; The inspection system according to any one of claims 1 to 4.

6. an output module (500) having a user interface configured to display the defect-location information. The inspection system according to any one of claims 1 to 5.

7. 1. A method for detecting defects with an inspection system, comprising: at least one camera unit (102a, 102b) configured to capture an image of the substrate (108); at least one light source generating a light beam that illuminates the substrate (108); one or more lens units disposed along an optical path of the camera units (102a, 102b) to provide a focal range for imaging the substrate (108), a first lens (104a) fixed to at least one of the camera units (102a, 102b) configured with a first focal range for imaging the substrate (108); a second lens (104b) fixed to at least one of the camera units (102a, 102b) configured with a second focal range for imaging a constituent layer of the substrate (108); A lens unit having imaging the substrate (108) with an imaging device (100) having processing by a processor (200) to extract first and second defect data from image data generated for the substrate (108) and constituent layers of the substrate (108); analyzing the defect data by an analysis module (300); Including, the analysis module (300) includes a defect location sub-module (300a) that analyzes the first defect data and the second defect data and generates a defect data set that includes defect location information for both the substrate (108) and constituent layers of the substrate (108). method.

8. transporting the substrate (108) between the camera units (102a, 102b) by a transporter (110) for imaging. The method of claim 7.

9. storing the one or more data sets including the image data, the defect data, and the defect data set in a database (400); 9. The method according to claim 7 or 8.

10. displaying defect information relating to both the substrate (108) and the constituent layers of the substrate (108) via an output module (500); the output module (500) includes a user interface for displaying the information; The method according to any one of claims 7 to 9.

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