Chip mark detection system and chip mark detection method

Abstract

The invention provides a chip mark detection system and method, and the method comprises the steps: controlling an objective table for bearing a wafer to move in a plane based on a preset path, carrying out the optical detection of a positioning mark in the wafer through a first light path located at a first side of the wafer in a moving process, and obtaining a first image, performing optical detection on the chip mark in the wafer through a second light path located on the second side of the wafer to obtain a second image; determining mark coordinates of the positioning marks in the wafer through the first image, determining chip position information of each chip in the wafer based on the mark coordinates and layout information of the wafer, and determining mark coordinates of the chip marks in the wafer through the second image, the chip position information is compared with the mark coordinates to obtain a first detection result of the chip mark, the first detection result is used for identifying the deviation of the actual position, deviating from the preset position, of the chip mark in the chip, high-precision alignment is achieved, and the detection efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of chip inspection, and in particular to a chip marking inspection system and a chip marking inspection method. Background Technology

[0002] To achieve chip-level traceability, such as in 3D packaging and SiP (System-in-Package), advanced semiconductor wafer packaging and testing plants need to mark each chip individually, such as with an ID mark. The marking process usually uses non-contact laser marking on the back of the wafer, and the marking position on the back needs to be concentric with the chip position on the front.

[0003] In related technologies, a step-by-step detection method is typically used to detect the position of chip markings on each chip. Specifically, the chips are first located on the front side of the wafer, and then the wafer is flipped over to detect the position of the chip markings on the back side.

[0004] However, mechanical errors are easily introduced during the flipping process, which reduces the alignment accuracy and makes it impossible to accurately determine whether the chip mark is located in the correct position on the chip. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a chip mark detection system and method, which realizes simultaneous detection of front-side alignment and back-side chip marks, achieving high-precision alignment and improving detection efficiency. The specific solution is as follows:

[0006] On one hand, this application provides a chip mark detection system, including:

[0007] A stage is used to hold wafers.

[0008] A first optical path located on the first side of the wafer, the first optical path being used to perform optical detection on the positioning mark located on the first side surface of the wafer to obtain a first image;

[0009] A second optical path located on the second side of the wafer is used to perform optical detection on the chip markings on the second side surface of the wafer to obtain a second image;

[0010] The processor is configured to control the stage carrying the wafer to move in a plane based on a preset path, and to analyze and obtain a first detection result of the chip mark based on the first image and the second image, wherein the first detection result is used to identify the deviation of the actual position of the chip mark in the chip from the preset position.

[0011] Further, the processor analyzes the first image and the second image to obtain a first detection result of the chip mark, including:

[0012] The processor determines the coordinates of the positioning markers in the wafer using the first image; based on the marker coordinates and the wafer layout information, it determines the chip position information of each chip in the wafer, wherein the layout information is used to identify the positional distribution of the positioning markers and the chips in the wafer;

[0013] The processor determines the coordinates of a chip marker in the wafer using the second image, whereby one chip marker is used to mark a chip in the wafer; the chip location information is compared with the marker coordinates to obtain a first detection result of the chip marker.

[0014] In another aspect, this application provides a chip mark detection method, comprising:

[0015] Based on a preset path, the stage carrying the wafer moves in a plane. During the movement, the positioning mark in the wafer is optically detected by the first optical path located on the first side of the wafer to obtain a first image, and the chip mark in the wafer is optically detected by the second optical path located on the second side of the wafer to obtain a second image.

[0016] Based on the analysis of the first image and the second image, a first detection result of the chip mark is obtained. The first detection result is used to identify the deviation of the actual position of the chip mark in the chip from a preset position.

[0017] Further, the step of obtaining the first detection result of the chip mark based on the analysis of the first image and the second image includes: determining the mark coordinates of the positioning mark in the wafer through the first image;

[0018] Based on the marker coordinates and the wafer layout information, the chip position information of each chip in the wafer is determined, and the layout information is used to identify the positioning markers and the chip position distribution in the wafer;

[0019] The second image is used to determine the coordinates of the chip marker in the wafer, wherein one chip marker is used to mark one chip in the wafer;

[0020] The chip position information is compared with the marker coordinates to obtain a first detection result of the chip marker. The first detection result is used to identify the deviation of the actual position of the chip marker in the chip from the preset position.

[0021] This application provides a chip marking detection system and method. Based on a preset path, a stage carrying a wafer moves in a plane. During the movement, a positioning mark image is obtained by optically detecting a positioning mark on the wafer through a first optical path located on the first side of the wafer, and a second image is obtained by optically detecting a chip mark on the wafer through a second optical path located on the second side of the wafer. The first image is used to determine the coordinates of the positioning mark on the wafer. Based on the positioning mark coordinates and the wafer layout information, the chip position information of each chip on the wafer is determined. The layout information is used to identify the positional distribution of the positioning mark and the chip on the wafer. The second image is used to determine the coordinates of the chip mark on the wafer. One chip mark is used to mark one chip on the wafer. The chip position information is compared with the mark coordinates to obtain a first detection result of the chip mark. The first detection result is used to identify the deviation of the actual position of the chip mark on the chip from the preset position. In this way, this application deploys an optical path on each side of the wafer. The first optical path is used to locate the chip on the front side of the wafer, while the second optical path locates the chip marking on the back side of the wafer. This enables simultaneous position detection on both sides of the wafer, and then the chip coordinates are matched with the chip marking coordinates. This eliminates the need to flip the wafer, significantly improving the accuracy of the relative position between the chip marking and the chip, and allowing for more precise determination of whether the chip marking is in the correct position on the chip. Furthermore, simultaneous detection on both sides of the wafer greatly improves detection efficiency, meeting the requirements of high-speed production lines, achieving efficient and high-precision chip marking detection, and enabling the miniaturization of the detection system. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic flowchart of a chip mark detection method provided in an embodiment of this application is shown;

[0024] Figure 2 This paper shows a schematic diagram of the structure of a chip marking detection system provided in an embodiment of this application;

[0025] Figure 3 A schematic diagram of a first optical path provided in an embodiment of this application is shown;

[0026] Figure 4 A schematic diagram of a second optical path provided in an embodiment of this application is shown.

[0027] Reference numerals: Stage 1, First optical path 2, Second optical path 3, Processor 4, Wafer 100, First bright-field light source 201, First filter switching device 202, First beam splitter 203, First autofocus sensor 204, Second beam splitter 205, First objective lens 206, First light intensity detection sensor 207, First filter 208, First area array detection camera 209, Ring dark-field light source 301, Second objective lens 302, Third beam splitter 303, Fifth beam splitter 304, Second area array detection camera 305, Second bright-field light source 306, Second filter switching device 307, Second autofocus sensor 308, Fourth beam splitter 309, Second light intensity detection sensor 310, Sixth beam splitter 311, Area array color rewind camera 312, Second filter 313. Detailed Implementation

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0031] As described in the background section, numerous chips (dies) are often fabricated on the front side of a wafer, arranged in a vertical and horizontal pattern. On the back side of the wafer, corresponding to each chip on the front side, there are laser-marked ID marks. A step-by-step detection method is typically used to detect the position of these chip marks on each chip. Specifically, the chips are first positioned on the front side of the wafer, then the wafer is flipped over to detect the position of the chip marks on the back side. However, the flipping process can easily introduce mechanical errors, reducing alignment accuracy and making it impossible to accurately determine whether the chip marks are located in the correct positions on the chip.

[0032] Based on the above technical problems, this application provides a chip marking detection system and method. This application deploys an optical path on each side of the wafer. The first optical path is used to locate the chip on the front side of the wafer, while the second optical path locates the chip marking on the back side of the wafer, achieving simultaneous position detection of both sides of the wafer. The chip coordinates are then matched with the chip marking coordinates, eliminating the need to flip the wafer and significantly improving the accuracy of the relative position between the chip marking and the chip. This allows for more precise determination of whether the chip marking is located in the appropriate position on the chip. Furthermore, simultaneous detection of both sides of the wafer greatly improves detection efficiency, meeting the needs of high-speed production lines and achieving efficient and high-precision chip marking detection, while also miniaturizing the detection system. Additionally, the two optical paths employ real-time autofocus, adapting to wafers with large warpage and suitable for various applications requiring simultaneous detection of double-sided optical features, such as semiconductor packaging and precision electronic assembly. In summary, this application achieves simultaneous detection of front-side alignment and back-side chip markings through coaxial optical path beam splitting design and multispectral imaging technology, achieving high-precision alignment and improved detection efficiency.

[0033] For ease of understanding, the chip mark detection method provided in this application embodiment will be described in detail below with reference to the accompanying drawings.

[0034] Refer to the attached diagram. Figure 1 This is a schematic flowchart of a chip marker detection method provided in an embodiment of this application. Figure 2 This is a schematic diagram of the chip marking detection system provided in an embodiment of this application. Figure 3 and Figure 4 These are schematic diagrams of the optical path structures for the first and second optical paths, respectively. The following will combine... Figure 2-4 right Figure 1 The chip mark detection method described herein may include the following steps.

[0035] S101, the stage 1 carrying the wafer 100 moves in a plane based on a preset path control. During the movement, the positioning mark in the wafer 100 is optically detected by the first optical path 2 located on the first side of the wafer 100 to obtain a first image, and the chip mark in the wafer 100 is optically detected by the second optical path 3 located on the second side of the wafer 100 to obtain a second image.

[0036] The chip marking detection method provided in this application is applied to a chip marking detection system. The chip marking detection system includes a stage 1 (such as a chuck set on a displacement motion mechanism) for carrying a wafer 100, a first optical path 2 located on the first side of the wafer 100, a second optical path 3 located on the second side of the wafer 100, and a processor 4. The first optical path 2 and the second optical path 3 can be arranged vertically around the center of the wafer 100.

[0037] The first side and the second side of wafer 100 refer to the upper surface and the lower surface of wafer 100, respectively. For ease of description, the first optical path 2 located on the first side of wafer 100 can be an upper square array optical system located on the upper surface of wafer 100, and the second optical path 3 located on the second side of wafer 100 can be a lower square array optical system located on the lower surface of wafer 100. Since the stage supporting wafer 100 is transparent, it can support wafer 100 without affecting the illumination and imaging of the second optical path 3. Therefore, the second optical path 3 can directly inspect the back side of wafer 100. The first optical path 2 is used for optical inspection of the front side of wafer 100. The stage 1 can support wafers of different sizes or types, such as a 12-inch wafer 100.

[0038] In this application, references Figure 2 The stage 1 has an optical medium structure to allow the light beam from the second optical path 3 to be transmitted to the second side surface of the wafer 100 through refraction or transmission. For example, if the stage 1 is made of transparent glass, the light beam can be refracted through. If the stage 1 is made of thin materials such as ceramic, glass, metal, or plastic, the light beam (usually longer wavelength light, such as infrared light) can be transmitted through. Alternatively, the stage 1 has a hollow structure to allow the light beam from the second optical path 3 to propagate in a straight line to the second side surface of the wafer 100. For example, the stage 1 can form a hollow structure using through holes and edge supports, allowing the light beam to pass through the hollow structure and directly enter the second side surface of the wafer 100.

[0039] refer to Figure 3 The diagram shown is a schematic representation of a first optical path provided in an embodiment of this application. (Refer to...) Figure 4 The diagram shown is a schematic representation of a second optical path 3 provided in an embodiment of this application. Further details will follow. Figure 3 and Figure 4 It should be noted that stage 1 was not in Figure 3 and Figure 4 As shown in the image.

[0040] The first optical path 2 may include a first bright-field light source 201, a first beam splitter 203, a second beam splitter 205, a first objective lens 206, and a first area array detection camera 209. The first bright-field light source 201 can be used to emit light, for example, a white light source from an LED. The light emitted by the first bright-field light source 201 can sequentially pass through the first beam splitter 203, the second beam splitter 205, and the first objective lens 206 and be incident on the upper surface (i.e., the first side surface) of the wafer 100. The reflected light from the upper surface, after passing through the first objective lens 206 and the second beam splitter 205, can be received by the first area array detection camera 209 to obtain a first image. As an example, the first area array detection camera 209 can be an area array monochrome detection camera. The imaging range of the first image can be larger than a single chip on the front side of the wafer 100. A first image may include one or more chips to ensure complete imaging of a single chip. It can be understood that here, the positioning mark located on the first side surface of the wafer 100 is optically detected by means of vertical illumination and bright-field imaging using the first optical path 2. Of course, in some cases, the first optical path 2 can also perform optical detection on the positioning mark on the first side surface of the wafer 100 by means of oblique illumination and bright field imaging (or even dark field imaging).

[0041] Specifically, the stage 1 can move in space by being driven by the motion platform (stage). The preset path is the pre-set movement path of the stage 1. Based on the preset path, the stage 1 carrying the wafer 100 is controlled to move in the plane so as to detect the chips at different positions on the wafer 100.

[0042] During the movement, the first optical path 2 can be used to optically detect the positioning marks on the front side of the wafer 100 to obtain a first image, which can show the positioning marks. The positioning marks are, for example, positioning marks located at the intersection of the dicing channels, and can be cross marks. Four cross marks are usually located at the four corners of the periphery of a chip. The dicing channels are located between adjacent chips in the wafer 100 to achieve chip separation.

[0043] Each chip has a chip mark on its back, which is used to identify each chip. The chip mark can be a pattern, text mark, etc. The chip mark in the wafer 100 is optically detected by the second optical path 3 located on the second side of the wafer 100 to obtain a second image, which shows the chip mark.

[0044] refer to Figure 4As shown, the second optical path 3 may include a ring-shaped dark-field light source 301, a third beam splitter 303, a second objective lens 302, and a second area array detection camera 305. The light beam emitted by the ring-shaped dark-field light source 301 can be incident on the second side surface of the wafer 100. The scattered light from the second side surface passes sequentially through the second objective lens 302 and the third beam splitter 303 and is received by the second area array detection camera 305 to obtain a second image. The second area array detection camera 305 can be an area array monochrome detection camera. The imaging range of the second area array detection camera 305 can be larger than a single chip on the front side of the wafer 100. A second image may include one or more chip marks to ensure complete imaging of a single chip mark. It can be understood that here, the chip marks on the second side surface of the wafer 100 are optically detected by means of oblique illumination and dark-field imaging using the second optical path 3. Of course, in some cases, the first optical path 2 can also optically detect the chip marks on the second side surface of the wafer 100 by means of vertical illumination and bright-field imaging.

[0045] S102, determine the coordinates of the positioning mark in the wafer 100 using the first image.

[0046] Specifically, the processor 4 can determine the coordinates of the positioning mark in the wafer 100 through the first image. The coordinates refer to the coordinates of the positioning mark, which are used to indicate the specific position of the positioning mark in the wafer 100. For example, based on the distance the motion platform moves when the first image is captured, and the position of the positioning mark in the first image, the coordinates of the positioning mark in the wafer 100 can be obtained.

[0047] S103, based on the marker coordinates and the layout information of wafer 100, determines the chip position information of each chip in wafer 100.

[0048] The layout information is used to identify the location markers and the distribution of chips within wafer 100. For example, the layout information can be a MAP of wafer 100, showing the distribution of all chips and location markers within wafer 100. Thus, based on the marker coordinates and the layout information, the chip location information of each chip within wafer 100 can be determined. This chip location information can be, for example, the chip coordinates of each chip within wafer 100.

[0049] In practical applications, the processor 4 can identify the positioning marks at the intersection of the cutting tracks and the cutting tracks in the first image, thereby determining the coordinates of the marks. Combined with the MAP map, the chip coordinates of each chip can be determined, thus clarifying the specific position of each chip in the wafer 100.

[0050] Furthermore, the positioning marker can also be a specific chip within wafer 100, which differs from other chips and is primarily used for wafer 100 positioning. That is, processor 4 can obtain the marker coordinates by recognizing the mark on a specific chip in the first image, thereby obtaining the chip position information.

[0051] S104, determine the coordinates of the chip marker in the wafer 100 using the second image.

[0052] Specifically, the coordinates of the chip marker located on the back side within the wafer 100 can be determined using the second image. A chip marker is used to mark one chip within the wafer 100. For example, the marker coordinates can be obtained based on the distance the motion platform traveled when the second image was captured, and the position of the chip marker in the second image.

[0053] S105, compare the chip position information with the marker coordinates to obtain the first detection result of the chip marker. The first detection result is used to identify the deviation of the actual position of the chip marker in the chip from the preset position.

[0054] Since chip location information indicates the specific position of a single chip within wafer 100, and marker coordinates indicate the specific position of a chip marker within wafer 100, and each chip marker is located on a single chip, a first detection result can be obtained by comparing the chip location information and the marker coordinates. The first detection result shows the relative position (actual position) of the chip marker within a single chip, and the deviation of the actual position from the ideal preset position, thereby detecting whether the chip marker has shifted. When the first detection result indicates that the deviation between the two meets the requirements, the chip marker can be considered to be in the appropriate position on the chip, and the detection is considered successful.

[0055] In this way, this application deploys an optical path on each side of the wafer 100. The first optical path 2 is used to locate the chip on the front side of the wafer 100, while the second optical path 3 locates the chip marking on the back side of the wafer 100. This enables simultaneous position detection of both the front and back sides of the wafer 100, and then matches the chip coordinates with the chip marking coordinates. This eliminates the need to flip the wafer 100, significantly improving the accuracy of the relative position between the chip marking and the chip, and allowing for more precise determination of whether the chip marking is located in the appropriate position on the chip. Furthermore, by simultaneously detecting both the front and back sides of the wafer 100, the detection efficiency is greatly improved, meeting the requirements of high-speed production lines, achieving efficient and high-precision chip marking detection, and realizing the miniaturization of the detection system.

[0056] In one possible implementation, the method may further include identifying chip markings in the second image to obtain a second detection result of the chip markings, wherein the second detection result is used to identify at least one of the following: the chip markings have character defects and the chip markings have character content errors.

[0057] Since chip markings may also contain errors, defects, or dirt, to achieve comprehensive chip marking detection, the chip markings in the second image can be identified to obtain a second detection result. In practical applications, processor 4 can identify the string of the chip marking in the second image to obtain the character's position, character defects, and character content. In other words, the second detection result can show that the chip marking has at least one of the following: character defects or incorrect character content.

[0058] In this way, while detecting whether the chip markings are off-target, it can also detect whether the chip markings are incorrect, defective, or covered by dirt, thus improving the comprehensiveness of the detection. It also eliminates the need to set up a separate optical path for defect detection, thereby improving the detection efficiency.

[0059] In one possible implementation, the chip marker may include a first sub-marker with a pattern style and a second sub-marker with a character style. The first sub-marker is used for positioning, and the second sub-marker is used to distinguish each chip. The first detection result includes the first sub-detection result and the second sub-detection result. Determining the marker coordinates of the chip marker in the wafer 100 using a second image includes: determining the first coordinates of the first sub-marker in the wafer 100 and the second coordinates of the second sub-marker in the wafer 100 using the second image. Comparing the chip position information with the marker coordinates to obtain the first detection result of the chip marker includes: comparing the chip position information with the first coordinates to obtain the first sub-detection result of the chip marker. The first sub-detection result is used to identify the deviation of the actual position of the first sub-marker in the chip from a preset position. Comparing the chip position information with the second coordinates to obtain the second sub-detection result of the chip marker. The second sub-detection result is used to identify the deviation of the actual distribution position of the second sub-marker in the chip marker from a preset distribution position.

[0060] Specifically, chip markings typically consist of patterns and characters, including a first sub-marker with a pattern and a second sub-marker with a character. The first sub-marker, for example, is a circle, which is used to locate the position of the entire chip marking. The second sub-marker, for example, is a string of characters. The second sub-marker is usually different on different chips, thus enabling the differentiation between different chips.

[0061] When determining the coordinates of the chip marker, the first coordinates of the first sub-marker in wafer 100 and the second coordinates of the second sub-marker in wafer 100 are determined. For example, the processor 4 determines the position of the chip marker by recognizing the pattern of the chip marker in the second image, and further, obtains the position of the string by recognizing the string in the chip marker.

[0062] Next, the chip position information obtained from the front detection is compared with the first coordinate. The first sub-detection result shows the actual position of the first sub-mark in the chip and the deviation from the ideal preset position. In other words, the first sub-mark is used to represent the entire chip mark to determine how much the entire chip mark deviates from the preset position.

[0063] By comparing the chip position information with the second coordinates, the second sub-detection result can show the distribution position of the character in the entire chip mark and the deviation from the ideal preset distribution position.

[0064] In this way, when the chip markings on the back of the chip are complex, including both patterns and characters, comprehensive detection of the chip markings can be achieved by detecting both the patterns and characters in the second image, thus more accurately determining whether the patterns and characters meet the requirements.

[0065] In one possible implementation, the second optical path 3 may further include a second bright-field light source 306 and an area array color retrospective camera 312. The method may further include performing bright-field detection on the chip mark by the second bright-field light source 306 and the area array color retrospective camera 312 to obtain a bright-field retrospective color image when the deviation of the actual position of the chip mark in the first detection result identification chip mark from the preset position exceeds the preset deviation, or when the character defects of the chip mark and the character content errors of the chip mark satisfy the retrospective conditions.

[0066] Since the annular dark-field light source 301 is used to provide dark-field illumination, if the stage 1 is made of glass, it will be affected by glass reflection. Under dark-field illumination, the image of the chip markings will be clearer. Therefore, the annular dark-field light source 301 is used to provide dark-field illumination. However, if the chip markings are damaged, incorrect, or dirty, dark-field illumination will not easily highlight these defects. Therefore, a bright-field light source is also needed to provide bright-field illumination, in which case the image quality of the color camera will be better. Based on this, continue to refer to... Figure 4 As shown, the second optical path 3 may also include a second bright field light source 306 and an area array color camera 312.

[0067] The light beam emitted by the second bright-field light source 306 passes sequentially through the second filter switching device 307, the fourth beam splitter 309, the third beam splitter 303, and the second objective lens 302 before being incident on the second side surface (i.e., the back surface) of the wafer 100. The reflected light from the second side surface passes sequentially through the second objective lens 302, the third beam splitter 303, the fifth beam splitter 304, and the sixth beam splitter 311 before being received by the area array color retrospective camera 312 to obtain a bright-field retrospective color image. The bright-field retrospective color image is different from the black and white second image.

[0068] If the deviation of the chip marker from the preset position exceeds the preset deviation when the first detection result indicates the actual position of the chip marker within the chip, it means the chip marker position detection has failed. The preset deviation is a pre-set deviation and can also be 0. At this point, the chip marker can be bright-field detected using a second bright-field light source 306 and a color image capture camera 312 to obtain a bright-field color image. This allows the chip marker to be clearly represented, facilitating subsequent recording and processing.

[0069] When the character defects and errors in the character content of the chip mark, as identified by the second detection result, meet the conditions for re-enhancing, for example, when the character defects are severe and the character content is incorrect or omitted, it can be considered that the conditions for re-enhancing are met. The chip mark can be bright-field detected by the second bright-field light source 306 and the area array color re-enhancing camera 312 to obtain a bright-field re-enhanced color image.

[0070] In this way, when there is a large deviation in the position of the chip marking, or when the chip marking is damaged or dirty, these defects can be more clearly shown by taking a color image of the back of the chip again, which makes it easier for subsequent staff to deal with the defects.

[0071] In one possible implementation, the method may further include: determining a filter adapted to the film material based on the film material on the target side of the wafer 100, the filter being used to filter light of the color corresponding to the film material; adding the filter to the target optical path located on the target side of the wafer 100 through a filter switching device, so that the light beam emitted by the light source in the target optical path is incident on the wafer 100 through the filter, wherein when the target side of the wafer 100 is the first side, the target optical path is the first optical path 2, and when the target side is the second side, the target optical path is the second optical path 3.

[0072] In either the first optical path 2 or the second optical path 3, a filter can be added. This filter can filter light of a specific color. Since there are many choices of film materials on the first or second side of wafer 100, some film materials can affect the detection and imaging. For example, copper wires are usually placed on the front side of wafer 100 to achieve electrical connections between different film layers. However, red copper wires can affect the imaging effect. Therefore, a suitable filter can be determined based on the film material. When the film material is copper, the filter is a red filter.

[0073] By switching different filters using the first filter switching device 202 or the second filter switching device 307, the filter is added to the first optical path 2 or the second optical path 3, so that the light beam emitted by the light source is filtered out after passing through the filter, and then incident on the wafer 100 to perform bright field detection or dark field detection to obtain an image.

[0074] In this way, the addition of a filter can switch the spectrum of the light beam emitted by the light source, resulting in better imaging of the wafer 100 under a specific illumination spectrum, thus improving the imaging quality of the first and second images. Of course, in other possible implementations, the filter may not be inserted into the optical path, and white light illumination may be used directly. In addition, the first optical path 2 may also include a first filter 208, and the second optical path 3 may also include a second filter 313, which also achieves the filtering effect and further improves the imaging quality.

[0075] In one possible implementation, the first optical path 2 may further include a first autofocus sensor 204 and a first objective lens 206. Before optically detecting the positioning mark in the wafer 100 through the first optical path 2 located on the first side of the wafer 100 to obtain a first image, the method may further include: performing focus detection on the first side surface of the wafer 100 through the first autofocus sensor 204 to obtain a first distance in the vertical direction between the first side surface of the wafer 100 and the front focal plane of the first objective lens 206; and controlling the first objective lens 206 to move based on the first distance so that the first side surface of the wafer 100 is located at the front focal plane of the first objective lens 206.

[0076] In this system, the light beam emitted by the first autofocus sensor 204 passes through the first beam splitter 203, the second beam splitter 205, and the first objective lens 206 before being incident on the first side surface of the wafer 100. The reflected light from the first side surface returns along the original path and is then received by the first autofocus sensor 204 to achieve focused detection of the first side surface, thus obtaining the first distance in the vertical direction between the first side surface and the front focal plane of the first objective lens 206. In other words, the first autofocus sensor measures the distance between the first side surface of the wafer 100 and the front focal plane of the first objective lens 206, and the imaging effect is best when the first side surface of the wafer 100 is at the front focal plane of the objective lens.

[0077] The first objective lens 206 can be moved up and down according to the first distance, so that the first side surface is located at the front focal plane of the first objective lens 206. In practical applications, the first objective lens 206 is moved by adjusting the movement of the back plate in the first optical path 2.

[0078] In this way, by additionally setting a first autofocus sensor 204 in the first optical path 2, automatic focus adjustment is achieved, eliminating the need for manual focusing of the objective lens, which greatly saves debugging time. After autofocus is completed, optical inspection of the front side of the wafer 100 can be performed, improving inspection efficiency.

[0079] In one possible implementation, the second optical path 3 may further include a second autofocus sensor 308 and a second objective lens 302. Before optically detecting the chip markings in the wafer 100 through the second optical path 3 located on the second side of the wafer 100 to obtain a second image, the method may further include: performing focus detection on the second side surface of the wafer 100 using the second autofocus sensor 308 to obtain a second distance in the vertical direction from the front focal plane of the stage 1 to the second objective lens 302; obtaining the actual distance in the vertical direction from the second side surface of the wafer 100 to the front focal plane of the second objective lens 302 based on the second distance and the corresponding compensation distance of the stage 1; and controlling the second objective lens 302 to move based on the actual distance so that the second side surface of the wafer 100 is located at the front focal plane of the second objective lens 302.

[0080] In this process, the light beam emitted by the second autofocus sensor 308 passes sequentially through the fourth beam splitter 309, the third beam splitter 303, and the second objective lens 302 before being incident on the second side surface of the wafer 100. The reflected light from the second side surface passes sequentially through the second objective lens 302, the third beam splitter 303, and the fourth beam splitter 309 before being received by the second autofocus sensor 308 to achieve focused detection of the second side surface and obtain the second distance in the vertical direction from the front focal plane of the second objective lens 302.

[0081] Since the stage 1, made of glass, is affected by reflection, the optical path of the reflected light within the stage 1 needs to be factored in. This requires a compensation distance for the stage 1, which is determined based on parameters such as its refractive index. In other words, based on the second distance and the compensation distance, the actual distance between the second side surface of the wafer 100 and the front focal plane of the second objective lens 302 is obtained. The second objective lens 302 is then moved up and down according to this actual distance, ensuring that the second side surface is positioned at the front focal plane of the second objective lens 302. In practical applications, the second objective lens 302 is moved by adjusting the backplate movement in the second optical path 3.

[0082] In this way, by additionally setting a second autofocus sensor 308 in the second optical path 3, automatic focus adjustment is achieved, eliminating the need for manual focusing of the objective lens and greatly saving debugging time. Optical inspection of the back side of wafer 100 can be performed immediately after autofocus is complete, improving inspection efficiency. Furthermore, by considering the influence of the stage 1 on the optical path of the reflected light, the distance between the second side surface and the front focal plane of the second objective lens 302 can be accurately measured, ensuring accurate focusing on the back side of wafer 100.

[0083] In one possible implementation, the first optical path 2 may further include a first bright-field light source 201 and a first light intensity detection sensor 207. Before optically detecting the positioning mark in the wafer 100 through the first optical path 2 located on the first side of the wafer 100 to obtain the first image, the method may further include: detecting the light intensity of the light beam incident on the wafer 100 by the first light intensity detection sensor 207 to obtain a first actual light intensity; and adjusting the light intensity of the first bright-field light source 201 based on the difference between the first actual light intensity and the first preset light intensity.

[0084] During continuous testing of different chips on wafer 100, the light intensity of the beam emitted by the light source attenuates over time, failing to meet measurement requirements. Therefore, the light intensity of the beam incident on wafer 100 from the first bright-field light source 201 can be detected using the first light intensity detection sensor 207 to obtain the first actual light intensity. The first preset light intensity is a pre-set value that meets the bright-field measurement requirements. Based on the difference between the first actual light intensity and the first preset light intensity, the light intensity of the first bright-field light source 201 is adjusted, for example, by adjusting the luminous power, to achieve the first preset light intensity.

[0085] In one possible implementation, the second optical path 3 may further include a second bright field light source 306 and a second light intensity detection sensor 310. The method may further include: detecting the light intensity of the light beam incident on the wafer 100 by the second bright field light source 306 through the second light intensity detection sensor 310 to obtain a second actual light intensity; and adjusting the light intensity of the second bright field light source 306 based on the difference between the second actual light intensity and the second preset light intensity.

[0086] Similarly, in the second optical path 3, the light intensity of the beam incident on the wafer 100 by the second bright-field light source 306 can be measured by the second light intensity detection sensor 310 to obtain the second actual light intensity. The second preset light intensity is a pre-set light intensity value that meets the optical detection requirements. Based on the difference between the second actual light intensity and the second preset light intensity, the light intensity of the second bright-field light source 306 is adjusted to achieve the second preset light intensity.

[0087] This application also provides a chip marking detection system, referencing... Figure 2 , Figure 3 , Figure 4 As shown, the system includes:

[0088] Stage 1 is used to support wafer 100.

[0089] The first optical path 2 is located on the first side of the wafer 100. The first optical path 2 is used to perform optical detection on the positioning mark on the first side surface of the wafer 100 to obtain a first image.

[0090] The second optical path 3 is located on the second side of the wafer 100. The second optical path 3 is used to perform optical detection on the chip markings on the second side surface of the wafer 100 to obtain a second image.

[0091] The processor 4 is used to control the stage carrying the wafer to move in a plane based on a preset path, and to analyze and obtain a first detection result of the chip mark based on the first image and the second image. The first detection result is used to identify the deviation of the actual position of the chip mark in the chip from the preset position.

[0092] It should be noted that the processor 4 can control the stage carrying the wafer 100 to move in the plane based on a preset path; determine the coordinates of the positioning mark in the wafer 100 through the first image; determine the chip position information of each chip in the wafer 100 based on the mark coordinates and the layout information of the wafer 100, the layout information is used to identify the position distribution of the positioning mark and the chip in the wafer 100; determine the mark coordinates of the chip mark in the wafer 100 through the second image, one chip mark is used to mark one chip in the wafer 100; compare the chip position information with the mark coordinates to obtain the first detection result of the chip mark, the first detection result is used to identify the deviation of the actual position of the chip mark in the chip from the preset position.

[0093] In one possible implementation, the first optical path 2 includes a first bright-field light source 201, a first beam splitter 203, a second beam splitter 205, a first objective lens 206, and a first area array detection camera 209. The light beam emitted by the first bright-field light source 201 passes sequentially through the first beam splitter 203, the second beam splitter 205, and the first objective lens 206 before being incident on the first side surface of the wafer 100. The reflected light from the first side surface passes sequentially through the first objective lens 206 and the second beam splitter 205 before being received by the first area array detection camera 209 to obtain the first image.

[0094] The second optical path 3 includes a ring dark field light source 301, a third beam splitter 303, a second objective lens 302, and a second area array detection camera 305. The light beam emitted by the ring dark field light source 301 is incident on the second side surface of the wafer 100. The scattered light from the second side surface passes through the second objective lens 302 and the third beam splitter 303 in sequence and is received by the second area array detection camera 305 to obtain the second image.

[0095] In one possible implementation, the optical axis of the first objective lens 206 is coaxial with the optical axis of the second objective lens 302, thereby enabling the first optical path 2 and the second optical path 3 to simultaneously detect the front and back sides at the same location on the wafer 100, ensuring consistency in detection. Alternatively, in another possible implementation, the optical axes of the first objective lens 206 and the second objective lens 302 are offset, meaning they are not coaxial. The optical axes of the first objective lens 206 and the second objective lens 302 can be spatially separated by a certain distance, as long as the microscopic imaging fields of the first objective lens 206 and the second objective lens 302 partially overlap on the same projection plane.

[0096] In one possible implementation, the first optical path 2 may further include a first filter switching device 202, which is used to switch different filters to be added to the first optical path. The filters are located in the optical path between the first bright field light source 201 and the first beam splitter 203.

[0097] In one possible implementation, the first optical path 2 further includes a first autofocus sensor 204 and a first objective lens 206. The first autofocus sensor 204 is used to perform focus detection on the first side surface of the wafer 100. During the focus detection process, the light beam emitted by the first autofocus sensor 204 passes through the first beam splitter 203, the second beam splitter 205 and the first objective lens 206 in sequence and then enters the first side surface of the wafer 100. The reflected light from the first side surface passes through the first objective lens 206, the second beam splitter 205 and the first beam splitter 203 in sequence and is then received by the first autofocus sensor 204.

[0098] And / or, the second optical path 3 also includes a second autofocus sensor 308 and a second objective lens 302. The second autofocus sensor 308 is used to perform focus detection on the second side surface of the wafer 100. During the focus detection process, the light beam emitted by the second autofocus sensor 308 passes through the fourth beam splitter 309, the third beam splitter 303 and the second objective lens 302 in sequence and then enters the second side surface of the wafer 100. The reflected light from the second side surface passes through the second objective lens 302, the third beam splitter 303 and the fourth beam splitter 309 in sequence and is then received by the second autofocus sensor 308.

[0099] In one possible implementation, the first optical path 2 further includes a first light intensity detection sensor 207 for detecting the light intensity of the light beam incident on the wafer 100 by the first bright field light source 201.

[0100] And / or, the second optical path 3 also includes a second bright field light source 306 and a second light intensity detection sensor 310, for detecting the light intensity of the second bright field light source 306 and the light beam incident on the wafer 100.

[0101] In one possible implementation, the second optical path 3 also includes a second bright field light source 306, a second filter switching device 307, a fifth beam splitter 304, a sixth beam splitter 311, and an area array color rewind camera 312.

[0102] The light beam emitted by the second bright-field light source 306 passes sequentially through the second filter switching device 307, the fourth beam splitter 309, the third beam splitter 303, and the second objective lens 302 before being incident on the second side surface of the wafer 100. The reflected light from the second side surface passes sequentially through the second objective lens 302, the third beam splitter 303, the fifth beam splitter 304, and the sixth beam splitter 311 before being received by the area array color replay camera 312 to obtain a bright-field replay color image.

[0103] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by program instructions in hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium can be at least one of the following media: read-only memory (ROM), RAM, magnetic disk, or optical disk, etc., and other media capable of storing program code.

[0104] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0105] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0106] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A chip marking detection system, characterized in that, include: A stage is used to hold wafers. A first optical path located on the first side of the wafer, the first optical path being used to perform optical detection on the positioning mark located on the first side surface of the wafer to obtain a first image; A second optical path located on the second side of the wafer is used to perform optical detection on the chip markings on the second side surface of the wafer to obtain a second image; The processor is configured to control the stage carrying the wafer to move in a plane based on a preset path, and to analyze and obtain a first detection result of the chip mark based on the first image and the second image, wherein the first detection result is used to identify the deviation of the actual position of the chip mark in the chip from the preset position.

2. The system according to claim 1, characterized in that, The processor analyzes the first image and the second image to obtain a first detection result of the chip mark, including: The processor determines the coordinates of the positioning markers in the wafer using the first image; based on the marker coordinates and the wafer layout information, it determines the chip position information of each chip in the wafer, wherein the layout information is used to identify the positional distribution of the positioning markers and the chips in the wafer; The processor determines the coordinates of a chip marker in the wafer using the second image, whereby one chip marker is used to mark a chip in the wafer; the chip location information is compared with the marker coordinates to obtain a first detection result of the chip marker.

3. The system according to claim 1, characterized in that, The first optical path includes a first bright-field light source, a first beam splitter, a second beam splitter, a first objective lens, and a first area array detection camera. The light beam emitted by the first bright-field light source passes sequentially through the first beam splitter, the second beam splitter, and the first objective lens before being incident on the first side surface of the wafer. The reflected light from the first side surface passes sequentially through the first objective lens and the second beam splitter before being received by the first area array detection camera to obtain the first image.

4. The system according to claim 3, characterized in that, The second optical path includes a ring dark field light source, a third beam splitter, a second objective lens, and a second area array detection camera. The light beam emitted by the ring dark field light source is incident on the second side surface of the wafer. The scattered light from the second side surface passes through the second objective lens and the third beam splitter in sequence and is received by the second area array detection camera to obtain the second image. The optical axis of the first objective lens is coaxial with or offset from the optical axis of the second objective lens.

5. The system according to claim 1, characterized in that, The stage has an optical medium structure so that the light beam of the second optical path can propagate to the second side surface of the wafer through refraction or penetration, or the stage has a hollow structure so that the light beam of the second optical path can directly propagate to the second side surface of the wafer.

6. The system according to claim 3, characterized in that, The first optical path further includes a first filter switching device, which is used to switch different filters to be added to the first optical path. The filters are located in the optical path between the first bright field light source and the first beam splitter.

7. The system according to claim 3, characterized in that, The first optical path further includes a first autofocus sensor and a first objective lens. The first autofocus sensor is used to perform focus detection on the first side surface of the wafer. During the focus detection process, the light beam emitted by the first autofocus sensor passes through the first beam splitter, the second beam splitter and the first objective lens in sequence and then enters the first side surface of the wafer. The reflected light from the first side surface passes through the first objective lens, the second beam splitter and the first beam splitter in sequence and is received by the first autofocus sensor.

8. The system according to claim 4, characterized in that, The second optical path further includes a second autofocus sensor and a second objective lens. The second autofocus sensor is used to perform focus detection on the second side surface of the wafer. During the focus detection process, the light beam emitted by the second autofocus sensor passes through the fourth beam splitter, the third beam splitter and the second objective lens in sequence before being incident on the second side surface of the wafer. The reflected light from the second side surface passes through the second objective lens, the third beam splitter and the fourth beam splitter in sequence before being received by the second autofocus sensor.

9. The system according to claim 3, characterized in that, The first optical path further includes a first light intensity detection sensor for detecting the light intensity of the light beam incident on the wafer from the first bright field light source.

10. The system according to claim 4, characterized in that, The second optical path also includes a second bright field light source and a second light intensity detection sensor, used to detect the light intensity of the light beam incident on the wafer by the second bright field light source.

11. The system according to claim 4, characterized in that, The second optical path also includes a second bright field light source, a second filter switching device, a fifth beam splitter, a sixth beam splitter, and an area array color rewind camera; The light beam emitted by the second bright-field light source passes sequentially through the second filter switching device, the fourth beam splitter, the third beam splitter, and the second objective lens before being incident on the second side surface of the wafer. The reflected light from the second side surface passes sequentially through the second objective lens, the third beam splitter, the fifth beam splitter, and the sixth beam splitter before being received by the area array color retrospective camera to obtain a bright-field retrospective color image.

12. A chip mark detection method, characterized in that, include: Based on a preset path, the stage carrying the wafer moves in a plane. During the movement, the positioning mark in the wafer is optically detected by the first optical path located on the first side of the wafer to obtain a first image, and the chip mark in the wafer is optically detected by the second optical path located on the second side of the wafer to obtain a second image. Based on the analysis of the first image and the second image, a first detection result of the chip mark is obtained. The first detection result is used to identify the deviation of the actual position of the chip mark in the chip from a preset position.

13. The method according to claim 12, characterized in that, The step of obtaining the first detection result of the chip mark based on the analysis of the first image and the second image includes: The first image is used to determine the coordinates of the positioning markers in the wafer; based on the coordinates and the layout information of the wafer, the chip position information of each chip in the wafer is determined, wherein the layout information is used to identify the positional distribution of the positioning markers and the chips in the wafer; The second image is used to determine the coordinates of the chip marker in the wafer, wherein one chip marker is used to mark one chip in the wafer; The chip position information is compared with the marker coordinates to obtain a first detection result of the chip marker. The first detection result is used to identify the deviation of the actual position of the chip marker in the chip from the preset position.

14. The method according to claim 13, characterized in that, The chip marking includes a pattern-style first sub-marker and a character-style second sub-marker. The first sub-marker is used for positioning, and the second sub-marker is used to distinguish each chip. The first detection result includes the first sub-detection result and the second detection result. Determining the coordinates of the chip marker in the wafer using the second image includes: determining the first coordinates of the first sub-marker in the wafer and the second coordinates of the second sub-marker in the wafer using the second image; The step of comparing the chip position information with the marker coordinates to obtain a first detection result of the chip marker includes: comparing the chip position information with the first coordinates to obtain a first sub-detection result of the chip marker, wherein the first sub-detection result is used to identify the deviation of the actual position of the first sub-marker in the chip from a preset position; and comparing the chip position information with the second coordinates to obtain a second sub-detection result of the chip marker, wherein the second sub-detection result is used to identify the deviation of the actual distribution position of the second sub-marker in the chip marker from a preset distribution position.

15. The method according to claim 12, characterized in that, The method further includes: The second image is subjected to chip mark recognition to obtain a second detection result of the chip mark. The second detection result is used to identify at least one of the following: the chip mark has character defects and the chip mark has character content errors.

16. The method according to claim 15, characterized in that, The second optical path includes a second bright-field light source and an area array color rewind camera, and the method further includes: When the first detection result indicates that the actual position of the chip mark in the chip deviates from the preset position by more than a preset deviation, or when the second detection result indicates that the chip mark has character defects or character content errors, the chip mark is subjected to bright field detection by the second bright field light source and the area array color retrospective camera to obtain a bright field retrospective color image.

17. The method according to claim 12, characterized in that, The method further includes: Based on the film material on the target side of the wafer, a filter adapted to the film material is determined, and the filter is used to filter light of the color corresponding to the film material; The filter is added to the target optical path located on the target side of the wafer by a filter switching device, so that the light beam emitted by the light source in the target optical path passes through the filter and is incident on the wafer. When the target side of the wafer is the first side, the target optical path is the first optical path, and when the target side is the second side, the target optical path is the second optical path.

18. The method according to claim 12, characterized in that, The first optical path includes a first autofocus sensor and a first objective lens. Before obtaining a first image by optically detecting the positioning marks in the wafer through the first optical path located on the first side of the wafer, the method further includes: The first autofocus sensor is used to focus and detect the first side surface of the wafer to obtain the first distance in the vertical direction where the first side surface of the wafer deviates from the front focal plane of the first objective lens. Based on the first distance, the first objective lens is moved relative to the stage so that the first side surface of the wafer is located at the front focal plane of the first objective lens.

19. The method according to claim 12, characterized in that, The second optical path includes a second autofocus sensor and a second objective lens. Before optically detecting chip markings in the wafer through the second optical path located on the second side of the wafer to obtain a second image, the method further includes: The second autofocus sensor is used to focus and detect the second side surface of the wafer to obtain the second distance in the vertical direction from the front focal plane of the second objective lens; Based on the second distance and the compensation distance corresponding to the stage, the actual distance between the second side surface of the wafer and the front focal plane of the second objective lens in the vertical direction is obtained. Based on the actual distance, the second objective lens is moved relative to the stage so that the second side surface of the wafer is located at the front focal plane of the second objective lens.

20. The method according to claim 12, characterized in that, The first optical path includes a first bright-field light source and a first light intensity detection sensor. Before obtaining a first image by optically detecting the positioning mark in the wafer through the first optical path located on the first side of the wafer, the method further includes: The first actual light intensity is obtained by detecting the light intensity of the beam incident on the wafer by the first bright field light source using the first light intensity detection sensor. Based on the difference between the first actual light intensity and the first preset light intensity, the light intensity of the first bright field light source is adjusted.

21. The method according to claim 12, characterized in that, The second optical path further includes a second bright-field light source and a second light intensity detection sensor. Before obtaining a second image by optically detecting the chip markings in the wafer through the second optical path located on the second side of the wafer, the method further includes: The second actual light intensity is obtained by detecting the light intensity of the beam incident on the wafer by the second bright field light source using the second light intensity detection sensor. The light intensity of the second bright field light source is adjusted based on the difference between the second actual light intensity and the second preset light intensity.

Images