CN117690816A

CN117690816A - Wafer detection method, system, electronic equipment and storage medium

Info

Publication number: CN117690816A
Application number: CN202311510437.5A
Authority: CN
Inventors: 吴贵阳; 杨应俊
Original assignee: Silicon Electric Semiconductor Equipment Shenzhen Co ltd
Current assignee: Silicon Electric Semiconductor Equipment Shenzhen Co ltd
Priority date: 2023-11-13
Filing date: 2023-11-13
Publication date: 2024-03-12

Abstract

The embodiment of the application provides a wafer detection method, a wafer detection system, electronic equipment and a storage medium, and belongs to the technical field of semiconductor detection. The method comprises the following steps: moving target grains in the wafer to a preset target detection position, and sequentially collecting images of the wafer at different heights of the target detection position to obtain grain images containing the target grains at corresponding heights; extracting image characteristic values of a plurality of pixel points in the grain image aiming at the grain image acquired at each height, and determining peak characteristics from the plurality of image characteristic values; establishing a peak change curve based on peak characteristics respectively corresponding to grain images acquired at different heights, and extracting a height value corresponding to the vertex position in the peak change curve to obtain a target height value; if the target height value is not in the preset height threshold value range, determining that the corresponding target crystal grain is the abnormal crystal grain. The wafer detection efficiency can be improved.

Description

Wafer detection method, system, electronic equipment and storage medium

Technical Field

The present disclosure relates to the field of semiconductor inspection technologies, and in particular, to a wafer inspection method, a system, an electronic device, and a storage medium.

Background

A wafer is a base material for semiconductor manufacturing, and wafer dicing is a step in the semiconductor manufacturing process, specifically, performing dicing on a wafer to form a plurality of dies. Before the wafer is put into practical use, it needs to be tested in various aspects, including electrical inspection of the die with probes after the wafer is spread.

The wafer increases the spacing between the dies after film expansion, so that the wafer is often subjected to die overlapping or die tilting during storage and transportation, which results in the difficulty in determining the height of the dies, and further leads to the easy damage of the probes when the probes are used for electrical inspection of the dies. In the related art, the phenomenon of grain overlapping or grain tilting is checked by adopting a manual visual inspection method, which is time-consuming and labor-consuming, has low accuracy, greatly influences the normal operation of grain electrical inspection, and reduces the electrical inspection efficiency of the wafer.

Disclosure of Invention

The main objective of the embodiments of the present application is to provide a wafer inspection method, which can improve the efficiency of inspecting the electrical properties of a wafer.

To achieve the above object, a first aspect of an embodiment of the present application provides a wafer inspection method, including:

Moving target grains in the wafer to a preset target detection position, and sequentially collecting images of the wafer at different heights of the target detection position to obtain grain images containing the target grains at corresponding heights;

extracting image characteristic values of a plurality of pixel points in the grain image aiming at the grain image acquired at each height, and determining peak characteristics from the image characteristic values;

establishing a peak change curve based on the peak characteristics respectively corresponding to the grain images acquired at different heights, and extracting a height value corresponding to the vertex position in the peak change curve to obtain a target height value;

and if the target height value is not in the preset height threshold range, determining that the corresponding target crystal grain is the abnormal crystal grain.

In some embodiments, after the determining that the corresponding target die is a die with abnormal placement, the method further includes:

and re-determining another die in the wafer as the target die, and continuing to determine the target height value of the new target die until the corresponding target height value is determined on the target detection position by all dies in the wafer, thereby completing the detection of the wafer.

In some embodiments, the sequentially capturing images of the wafer at different heights of the target inspection position to obtain a die image including the target die at the corresponding height includes:

sequentially acquiring images of the wafer at different heights of a target detection position through image acquisition equipment, wherein the image acquisition equipment comprises a preset focusing distance;

and obtaining a grain image containing the target grain at the corresponding height based on the focusing distance.

In some embodiments, the extracting the image feature values of the plurality of pixels in the grain image for the grain image acquired at each height and determining the peak feature from the plurality of image feature values includes:

preprocessing the grain image to obtain a preprocessed grain image;

and obtaining a plurality of image characteristic values corresponding to a plurality of pixel points in the grain image according to the preprocessed grain image, and selecting the maximum value from the plurality of image characteristic values as a peak characteristic.

In some embodiments, if the target height value is not within the preset height threshold, determining that the corresponding target die is a die with abnormal placement includes:

And if the target height value is not in the preset height threshold range, determining that the grain closest to the image acquisition equipment is the target grain, wherein the target grain is the grain with abnormal placement.

determining abnormal grain coordinates of the target grains according to the grain image;

and stripping the target crystal grain from the wafer by utilizing a preset recovery mechanism according to the abnormal crystal grain coordinates to obtain the processed wafer.

In some embodiments, after said determining the abnormal grain coordinates of the target grain, further comprising:

acquiring a grain distribution diagram of the wafer;

and correspondingly marking the grain distribution map according to the abnormal grain coordinates to obtain the updated grain distribution map.

To achieve the above object, a second aspect of the embodiments of the present application proposes a wafer inspection system, including:

the moving module is used for moving target grains in the wafer to a preset target detection position, and sequentially collecting images of the wafer at different heights of the target detection position to obtain grain images containing the target grains at corresponding heights;

The first processing module is used for extracting image characteristic values of a plurality of pixel points in the grain image aiming at the grain image acquired at each height, and determining peak characteristics from the image characteristic values;

the second processing module is used for establishing a peak change curve based on the peak characteristics corresponding to the grain images acquired at different heights respectively, and extracting a height value corresponding to the vertex position in the peak change curve to obtain a target height value;

and the result module is used for determining that the corresponding target crystal grain is the abnormal crystal grain if the target height value is not in the preset height threshold range.

To achieve the above object, a third aspect of the embodiments of the present application provides an electronic device, where the electronic device includes a memory and a processor, where the memory stores a computer program, and the processor executes the computer program to implement the wafer inspection method according to the embodiment of the first aspect.

In order to achieve the above object, a fourth aspect of the embodiments of the present application proposes a storage medium, which is a computer-readable storage medium, storing a computer program, where the computer program is executed by a processor to implement the wafer inspection method according to the embodiment of the first aspect.

According to the wafer detection method, the system, the electronic equipment and the storage medium, target grains in the wafer are moved to a preset target detection position, and images of the wafer are sequentially collected at different heights of the target detection position, so that grain images containing the target grains at corresponding heights are obtained; it will be appreciated that the die image obtained when an abnormal die is present in the wafer is different from the die image obtained when no abnormal die is present in the wafer, particularly in the image feature values of the die image; then, extracting image characteristic values of a plurality of pixel points in the grain image aiming at the grain image acquired at each height, and determining peak characteristics from the plurality of image characteristic values; establishing a peak change curve based on peak characteristics respectively corresponding to grain images acquired at different heights, and extracting a height value corresponding to the vertex position in the peak change curve to obtain a target height value; if the target height value is not within the preset height threshold range, wherein the preset height threshold is obtained from a wafer without abnormal grains, and when the target height value exceeds the preset height threshold range, the corresponding target grains can be determined to be the grains with abnormal placement. By sequentially collecting the grain images of the wafer at different heights and determining peak characteristics from a plurality of image characteristic values in the grain images, whether abnormal grains exist can be judged without manually observing the grain images one by one, and the wafer detection efficiency is improved.

Drawings

FIG. 1 is an alternative die overlay schematic provided in an embodiment of the present application;

FIG. 2 is an alternative die tilt schematic provided in an embodiment of the present application;

FIG. 3 is a schematic diagram of an alternative configuration of a wafer inspection system according to an embodiment of the present application;

FIG. 4 is an alternative flow chart of a wafer inspection method provided in an embodiment of the present application;

FIG. 5 is a schematic diagram of an alternative conventional peak variation curve of a wafer inspection method according to an embodiment of the present application;

FIG. 6 is a schematic diagram of an alternative abnormal peak variation curve of a wafer inspection method according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram showing a comparison of variation curves of an alternative wafer inspection method according to an embodiment of the present disclosure;

FIG. 8 is a flow chart of one implementation of step S101 in FIG. 4;

FIG. 9 is a flow chart of one implementation of step S102 in FIG. 4;

FIG. 10 is a flow chart of one implementation after step S104 in FIG. 4;

FIG. 11 is a flow chart of one implementation after step S601 in FIG. 4;

FIG. 12 is a schematic diagram of a system functional module of a wafer inspection system according to an embodiment of the present disclosure;

fig. 13 is a schematic hardware structure of an electronic device according to an embodiment of the present application.

Reference numerals: the device comprises a first mobile module 10, an X platform 11, a Y platform 12, a slide holder 20, a shooting module 30, a motor 31, a vertical camera 32, a horizontal camera 33 and a bottom plate 40.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of the present application only and is not intended to be limiting of the present application.

Wafer is a basic material for semiconductor manufacture, and wafer film expansion is a step in the semiconductor manufacture process, and a plurality of dies can be formed by performing film expansion cutting on the wafer. Before the wafer is put into practical use, it needs to be tested in various aspects, including electrical inspection of the die with probes after the wafer is spread.

The wafer increases the spacing between the dies after film expansion, so that the phenomenon of die overlapping or die tilting often occurs in the process of storing and transferring the wafer, namely, each die after cutting should be closely attached to the surface of the blue film used for film expansion, however, in practical situations, the phenomenon of die overlapping (stacking) or die tilting (standing) often occurs due to the factor of unreliability during transferring.

This phenomenon results in a difficult determination of the height of the die, which in turn results in a tendency for the probes to be damaged when they are used to electrically inspect the die, typically by contacting metal pins or electrodes on the die surface. The probe is usually preset with a fixed detection height, when the stacked crystal or the standing crystal exists, the probe is blocked by the stacked crystal or the standing crystal when the probe does not descend to the preset height, and at the moment, the probe is damaged, and meanwhile, the efficiency of electrical detection is seriously affected.

In the related art, the wafers are inspected one by adopting a manual visual inspection method, so that time and labor are wasted, the accuracy is low, the normal operation of the electrical property detection of the crystal grains is greatly influenced, and the electrical property detection efficiency of the wafers is reduced.

Illustratively, as shown in fig. 1, fig. 1 is an alternative die overlap schematic diagram provided in the embodiment of the present application, in which die a overlaps die B such that the probe should be lowered by a preset height H to contact the electrode of die a for electrical inspection, but die B prevents the probe from being lowered, such that the probe is damaged while failing to inspect die a successfully.

In another example, as shown in fig. 2, fig. 2 is an alternative die tilting schematic diagram provided in the embodiment of the present application, in which die C is tilted, so that die C is standing up, and thus, die C obstructs the probe from dropping by a preset height H for electrical inspection, and the probe is damaged while failing to inspect die C successfully.

Based on this, the embodiment of the application provides a wafer detection method, a system, an electronic device and a storage medium, which can improve the efficiency of wafer electrical detection.

The wafer inspection method, system, electronic device and storage medium provided in the embodiments of the present application are specifically described through the following embodiments, and the wafer inspection system in the embodiments of the present application is described first.

As shown in fig. 3, fig. 3 is a schematic diagram of an alternative structure of a wafer inspection system according to an embodiment of the present application, where the wafer inspection system is composed of a first moving module 10, a stage 20, and a shooting module 30. Wherein the first mobile module 10 comprises an X-stage 11 and a Y-stage 12; the photographing module 30 includes a motor 31, a vertical camera 32, and a horizontal camera 33. In addition, the wafer inspection system further includes a base plate 40 for supporting the wafer, and the wafer is placed on the stage 20 when the wafer is required to be electrically inspected, wherein the stage 20 can move along with the first moving module 10 in a lateral direction parallel to the base plate 40, for example, when the X stage 11 moves, the wafer can move along with the first moving module, and when the Y stage 12 moves, the wafer can move along with the second moving module, and it should be noted that the lateral and longitudinal directions refer to directions on a plane parallel to the base plate 40.

Next, the first moving module 10 moves the target die of the wafer to the target inspection position, and the photographing module 30 is generally located above the target inspection position, the vertical camera 32 is connected to the motor 31, and when the motor 31 moves in a direction perpendicular to the base plate 40, the vertical camera 32 can move along with it and photograph the corresponding die image at different heights, and in addition, the horizontal camera 33 can photograph the detailed image of the wafer to observe the microscopic morphology of the die.

And then, the shot multiple grain images are sent to an image processing module, wherein the image processing module can be one sub-module in the wafer detection system or one sub-module additionally connected with the wafer detection system. The image processing module can process the images of the plurality of crystal grains and obtain a processing result so as to determine whether the situation of stacking or standing crystals exists according to the processing result.

Here, the standing crystal includes a case where the crystal grains are completely erected as shown in fig. 2, and also includes a case where the crystal grains are inclined at an angle.

The foregoing is a brief description of a wafer inspection system according to an embodiment of the present application, and for better understanding, a wafer inspection method according to the present application will be further described based on the foregoing wafer inspection system. In the embodiment of the application, the wafer detection method can be applied to a wafer detection system.

The wafer inspection method in the embodiment of the present application may be described by the following embodiment.

It should be noted that, in each embodiment of the present application, when related processing according to user information is required, permission or consent of the user is obtained first, for example, when identity information of the user is obtained to start the wafer inspection system, permission or consent of the user is obtained first. Moreover, the collection, use, processing, etc. of such data would comply with relevant laws and regulations.

As shown in fig. 4, fig. 4 is an optional flowchart of a wafer inspection method according to an embodiment of the present application, and the method in fig. 4 may include, but is not limited to, steps S101 to S104.

Step S101, moving target grains in the wafer to a preset target detection position, and sequentially collecting images of the wafer at different heights of the target detection position to obtain grain images containing the target grains at corresponding heights.

In some embodiments, the image capture device, i.e., the vertical camera 32 in the system described above, may be pre-configured and adjusted to be aligned with the target inspection location and to move the target die in the wafer to the target inspection location to capture die images at different heights at the target inspection location.

Further, a wafer includes a plurality of dies, and the target die may be one die in the wafer, or the plurality of dies, and the die images acquired at different heights of the target inspection location should include the target die, regardless of the number of dies.

Further, the image capturing device may be a device capable of capturing an image, such as a camera, a cellular phone, an infrared camera, or a high-resolution video camera.

Further, the different heights refer to the heights of the image acquisition device from the target crystal grains, and a plurality of fixed points can be preset above the target detection position to shoot the wafer, so that the crystal grain images of the target detection position at the different heights are obtained.

Step S102, extracting image characteristic values of a plurality of pixel points in the grain image according to the grain image acquired at each height, and determining peak characteristics from the plurality of image characteristic values.

In some embodiments, the grain image of the target grain at each height is sent to an image processing module, where the image processing module includes an image processing device, and the image processing device can extract an image feature value corresponding to a pixel point from each grain image, and select a maximum value from the image feature value as a peak feature.

In some embodiments, the image processing device may process the grain image to obtain a gray feature value corresponding to each pixel, where the gray feature value is used to describe a gray level distribution in the image, and reflects brightness and contrast information of the image. It will be appreciated that when the image processing apparatus photographs the target die, if a die stacking or standing situation occurs, the closest distance between the die and the image capturing apparatus will be changed, so that the gray characteristic value is different from that of a wafer in which the die stacking or standing situation does not occur, so that the gray characteristic value of the pixel point in the die image photographed at each height can be captured, and the gray characteristic value is input into the image processing apparatus.

Further, the selected pixel point may be each pixel point in the grain image, or may be a preset pixel point, for example, a center pixel point of the grain image and a plurality of pixel points around the center pixel point may be selected as pixel points of preset points. The number of the selected pixels may be set according to the actual situation, and the embodiment of the present application is not specifically limited.

In some embodiments, the image processing device may process the grain image to obtain a texture feature value corresponding to each pixel, where the texture feature value is used to describe texture information in the grain image, and characterizes texture structures and features of different areas in the grain image. Similarly, the selected pixel may be each pixel in the die image, or may be a predetermined pixel.

Further, a filter may be used to filter the grain image to extract texture features of the plurality of pixels in different directions and dimensions, or a wavelet transform method may be used to decompose the grain image in multiple dimensions to obtain wavelet coefficients, and statistical analysis may be performed on the wavelet coefficients in each dimension and direction to obtain texture feature values.

Further, if the stacking or standing situation occurs, the closest distance from the die to the image acquisition device will be changed, so that the texture feature value is different from that of the wafer without the stacking or standing situation, so that the texture feature value of the pixel point in the die image photographed at each height can be acquired and input into the image processing device.

Further, the image processing device can further process the gray characteristic value or the texture characteristic value to judge whether the situation of stacking or standing crystals exists, and it can be understood that the image processing device can perform image processing on a large number of crystal grain images at high speed and accurately, so that missing detection and low detection efficiency caused by manually observing the crystal grain images one by one are avoided, and the wafer detection efficiency is improved.

It should be noted that, the image feature value may also be other values capable of reflecting the feature of the pixel point of the grain image, and the present application is only illustrated by the preferred embodiment and not limited thereto.

And step S103, establishing a peak change curve based on peak characteristics corresponding to the grain images acquired at different heights, and extracting a height value corresponding to the peak position in the peak change curve to obtain a target height value.

In some embodiments, a certain inspection area of a wafer is moved to a target inspection position, and the inspection area is photographed at different heights by using an image capturing device, it is understood that a peak change curve established by the inspection area without stacking or standing crystals should be similar (referred to as a conventional peak change curve), in other words, a wafer with stacking or standing crystals may deviate from the conventional peak change curve due to a change of a structure between each crystal grain, so that whether the wafer has stacking or standing crystals can be determined according to the peak change curve established based on the crystal grain image.

Further, the height of the image acquisition device from the wafer is taken as an independent variable, the peak characteristic of the grain image correspondingly acquired under the height is taken as an independent variable, a peak change curve is established, and the height value of the image acquisition device corresponding to the highest point in the peak change curve is determined to be a target height value.

Step S104, if the target height value is not within the preset height threshold value range, determining that the corresponding target crystal grain is the abnormal crystal grain.

In some embodiments, a height threshold range is set based on a height value corresponding to a vertex position of a conventional peak change curve, and if the target height value is not within the height threshold range, it may be determined that a die with an abnormal placement exists at the target detection position.

Exemplary, as shown in FIG. 5, FIG. 5 is a schematic diagram of an alternative conventional peak variation curve of a wafer inspection method according to an embodiment of the present application, wherein z sitsThe target corresponds to the shooting height value G of the image acquisition equipment _MAX Corresponding to the peak characteristics of the grain images acquired under each shooting height value, drawing a conventional peak change curve shown in fig. 5 according to the peak characteristics of the grain images acquired under each shooting height value, wherein the curve represents the change condition of the peak characteristics of the grain images corresponding to the wafer under the condition of no stacking or standing crystal along with the height of the image acquisition equipment; as shown in fig. 6, fig. 6 is a schematic diagram of an abnormal peak change curve of an alternative wafer inspection method according to an embodiment of the present application, and a curve drawing method similar to a conventional peak change curve may obtain an abnormal peak change curve, where the curve represents a change condition of peak characteristics of a corresponding die image of a wafer with the height of an image capturing device under a situation that a wafer is stacked or standing. It can be found that, when the abnormal die (i.e. stacked die or standing die) exists on the wafer, the generated curve has a peak difference from the curve generated when the abnormal die does not exist on the wafer, as shown in fig. 7, fig. 7 is a schematic diagram showing a comparison of alternative variation curves of the wafer inspection method provided in the embodiment of the present application, where a larger deviation occurs at the vertex positions of the two variation curves, and the conventional peak variation curve is taken as a reference curve, that is, if the curve drawn according to the die image corresponding to the currently inspected wafer is inconsistent with the peak of the conventional peak variation curve, it can be determined that the abnormal die exists on the target inspection position on the wafer.

It can be understood that by processing a plurality of grain images captured at the target detection position, a peak change curve is drawn, and compared with a conventional peak change curve obtained in advance, abnormal grains of the wafer can be rapidly judged according to the difference of the two curves, and the positions of the abnormal grains are determined according to the target grains moving to the target detection position during detection, so that the omission and slow detection speed caused by manual visual inspection are avoided, and the wafer detection efficiency is improved.

In some embodiments, the step S104 may further include, but is not limited to, the following step S201:

step S201, re-determining another die in the wafer as a target die, and continuing to determine a target height value of the new target die until all dies in the wafer determine corresponding target height values at the target detection positions, thereby completing the detection of the wafer.

In some embodiments, the method similar to the above steps S101 to S104 continues to detect the target height value of the next target die, and compares the target height value with a preset height threshold, and similarly, if the target height value is not within the preset height range, it can be determined that the target die is an abnormally placed die.

For example, a wafer includes a die D and a die E to be inspected, after the inspection of the die D is completed, the die E may be moved to a target inspection position to inspect a target height value of the die E, and the target height value of the die E is compared with a predetermined height range, and after the inspection of the die D and the die E is completed, the inspection of the wafer is completed.

In some embodiments, a wafer includes a plurality of dies, and in order to ensure accuracy of inspection, the wafer is generally divided into a plurality of inspection areas, each inspection area includes one or more dies to be inspected, and after the inspection of the target dies in the current inspection area is completed, a next inspection area of the wafer may be moved to a target inspection position to inspect the next target dies.

As shown in fig. 8, fig. 8 is a flowchart of one implementation of step S101 in fig. 4, and the method in fig. 8 may include, but is not limited to including, step S301 to step S302.

In step S301, images of the wafer are sequentially acquired at different heights of the target detection position by an image acquisition device, where the image acquisition device includes a preset focusing distance.

In some embodiments, the image capturing device may select according to the actual situation as described in step S101, and the focusing distance may be preset in the image capturing device, where the focusing distance refers to a straight line distance from the object focal plane (the object) to the image focal plane (the image sensor), it may be understood that an object at the focusing distance may be clearer when the object at the focusing distance is finally imaged, and an object outside the focusing distance may be more blurred when the object at the focusing distance is finally imaged, based on this, when the crystal stacking or standing crystal phenomenon exists, a clear image of the crystal grain may be captured when the image capturing device is not lowered to the preset height, and the image feature values corresponding to the clear area and the blurred area of the crystal grain image are different, so that whether the abnormal crystal grain exists may be determined according to the image feature values of the multiple crystal grain images.

Further, the image acquisition device may include a point light source and a ring light source, and may select different light sources according to a specific wafer pattern and a reflection condition, so as to obtain an optimal die image.

Further, the moving module in the wafer inspection system may set a moving route in advance to move the target die to the target inspection position, and similarly, the image capturing device may capture a plurality of die images at different heights according to a preset program and send the die images to the image processing module, so that the image processing module performs image processing on the die images, and it can be understood that the inspection of the target die and the processing of the die images generated by the target die are all implemented in an automated manner, thereby greatly reducing the burden of manual inspection, and avoiding the problem of inaccurate inspection caused by manual inspection, so as to improve the efficiency of wafer inspection.

Step S302, based on the focusing distance, a grain image containing the target grain at the corresponding height is obtained.

In some embodiments, the focus distance of the image capture device may be fixed, based on which die images of the target die are taken at different heights.

For example, when an abnormal grain exists in a certain wafer, an image acquisition device with a preset focusing distance is used for shooting a target grain, it can be understood that under the condition of no abnormal grain, the target grain should be only one grain, however, the grain G and the grain H are stacked together, and the grain H is above the grain G, that is, the distance between the grain H and the image acquisition device is closer, and in the process that the image acquisition device continuously descends, the grain H firstly reaches the focusing distance of the image acquisition device, and at the moment, the grain H is clear and the grain G is blurred in the acquired grain image; then, the image acquisition device descends, if the crystal grain G and the crystal grain H are not completely overlapped, the crystal grain G reaches the focusing distance of the image acquisition device, and at the moment, in the acquired crystal grain image, the crystal grain G is clear and the crystal grain H is fuzzy. The image feature value at the image sharpness contains more image features than at the image blur, so that when there are abnormal grains in the wafer, the curve drawn based on the grain image will have two vertex values as shown in fig. 6.

Or if the crystal grain G and the crystal grain H are completely overlapped, the image acquisition device only acquires the crystal grain image which can be clearly represented by the crystal grain H, but the curve of the peak characteristic drawn by the image acquisition device along with the height of the image acquisition device is different from the position of the peak value of the conventional peak change curve, so that the abnormal crystal grain can be determined to exist at the position. Even if die G is not stacked with die H, the image capture device does not capture a clear image of the die at two different heights, as compared to the case where there are no abnormal dies in the wafer.

As shown in fig. 9, fig. 9 is a flowchart of one implementation of step S102 in fig. 4, and the method in fig. 9 may include, but is not limited to including, step S401 to step S402.

Step S401, preprocessing the grain image to obtain a preprocessed grain image.

In some embodiments, the grain image may be pre-processed prior to extracting the image feature values of the grain image, where the pre-processing operations may include denoising, contrast enhancement, sharpening, and the like.

It should be noted that, the preprocessing operation may further include an operation capable of improving the image quality of the crystal grain, such as feature normalization, and the embodiment of the present application is not particularly limited.

Step S402, according to the preprocessed grain image, obtaining a plurality of image characteristic values corresponding to a plurality of pixel points in the grain image, and selecting the maximum value from the plurality of image characteristic values as a peak characteristic.

In some embodiments, extracting the image feature value from the preprocessed grain image can reduce noise interference, more highlight the image feature in the grain image, and improve the robustness and generalization capability of the image feature value.

Further, after the preprocessed gray level image is obtained, each pixel point is determined to be (x, y), and an image characteristic value is obtained through an image processing module, for example, a computer is used for processing a grain image to obtain a gray level function P (x, y), new functions G (x) and G (y) can be constructed, and G (x, y) is calculated, which is specifically shown as the following formula:

G(x)＝|P(x+1,y)-P(x,y)| (1)

G(y)＝|P(x,y+1)-P(x,y)| (2)

Further, a maximum value G is extracted from the function G (x, y) _MAX As a peak feature.

In some embodiments, the step S104 may further include, but is not limited to, the following steps S501:

in step S501, if the target height value is not within the preset height threshold range, determining the grain closest to the image capturing device as the target grain, where the target grain is the grain with abnormal placement.

In some embodiments, if there is a vertex difference between a curve drawn according to a grain image obtained from a current target grain and a conventional peak change curve, determining a dependent variable corresponding to a vertex of the current detection drawn curve as a target height value, determining a preset height threshold range according to a reasonable fluctuation range of the vertex of the conventional peak change curve, and if the target height value is not within the preset height threshold range, determining that an abnormal grain exists at the current target detection position.

Further, no matter the phenomenon of stacking or standing crystals, the distance between the crystal grain and the image acquisition equipment is shortened because the crystal grain moves in position, so that the crystal grain closest to the image acquisition equipment at the target detection position can be determined as the target crystal grain, namely, the abnormal crystal grain is placed.

As shown in fig. 10, fig. 10 is a flowchart of one implementation after step S104 in fig. 4, and the method in fig. 10 may include, but is not limited to including, step S601 to step S602.

Step S601, determining abnormal grain coordinates of the target grains according to the grain image.

In some embodiments, the wafer is moved according to a certain sequence, and when only one target die is detected, and the target die is detected to be an abnormally placed die, then the abnormal die coordinates corresponding to the target die can be determined.

In some embodiments, the image capturing device includes a preset field area, and in the process of capturing an image, one field area may include a plurality of grains, where the detected target grains are a plurality of grains, and all grains in the field area may be captured by another image capturing device to obtain a nodding image of the grains, where all grains in the figure can be clearly presented, and when an abnormal grain occurs, the position of the abnormal grain may be determined by combining the previously captured grain images. Therefore, a plurality of crystal grains can be detected each time, and the detection speed of the wafer is further improved.

Further, the die depression image corresponds to the die positions in the die image one by one, so that the positions of abnormal dies in the field of view area can be determined, and corresponding abnormal die coordinates can be determined.

Further, the wafer may be moved using the first moving module 10 to move the die in each view field region to the target inspection position in a zigzag shape.

It should be noted that the moving direction of the first moving module 10 is not limited to the above direction, and may also move from top to bottom, from bottom to top, from left to right, from right to left, or move in cooperation with each other. The embodiment of the present application is not particularly limited.

In step S602, the target die is peeled from the wafer by using a predetermined recovery mechanism according to the abnormal die coordinates, so as to obtain the processed wafer.

In some embodiments, the recovery mechanism may include a recovery rotation device and a recovery gripping device, wherein the recovery rotation device is connected to the recovery gripping device, and the recovery rotation device is capable of driving the recovery gripping device to rotate when rotating. When abnormal grains exist in the wafer, the abnormal grains are positioned according to the coordinates of the abnormal grains, the abnormal grains are stripped from the wafer by using the recovery grabbing device, and then the recovery rotating device rotates and drives the recovery grabbing device to rotate to a pre-placed grain recovery area so as to uniformly recover the abnormal grains.

It can be understood that the wafer detection system is used for automatically detecting the wafer, and the recovery mechanism is used for automatically recovering abnormal grains, so that the detection efficiency of the wafer is greatly improved.

As shown in fig. 11, fig. 11 is a flowchart of one implementation after step S601 in fig. 4, and the method in fig. 11 may include, but is not limited to including, step S701 to step S702.

In step S701, a die distribution diagram of the wafer is obtained.

In some embodiments, the die MAP may be a wafer MAP, in particular, the wafer MAP may generally represent a rectangular or circular image, each small square or circle on the wafer MAP represents a region on the wafer, each region may represent a die, a chip, a device or a circuit on the wafer, and the wafer MAP may be used to describe information such as layout, electrical property distribution, defect distribution, etc. on the wafer.

Step S702, correspondingly marking the grain distribution diagram according to the abnormal grain coordinates to obtain an updated grain distribution diagram.

In some embodiments, the wafer MAP is in one-to-one correspondence with the die on the wafer, and when there is an abnormal die, the wafer MAP may be marked according to the abnormal die coordinates corresponding to the abnormal die.

Further, the wafer MAP can be edited by using related computer software, such as Virtuoso software, calibre software or Hercules software, so as to quickly and accurately modify the wafer MAP, thereby saving time and cost of manual operation.

Further, the MAP of the wafer after the marking includes the positions of all the abnormal dies on the wafer, and then the electrical inspection can be performed on the wafer according to the MAP of the wafer, and it can be understood that, since the abnormal dies are peeled off in advance and no dies exist at the coordinates of the abnormal dies, the probe for electrical inspection can be set, and the places marked as the abnormal dies on the MAP of the wafer are skipped, so that the time for electrical inspection is saved and the efficiency of electrical inspection of the wafer is improved.

As shown in fig. 12, another wafer inspection system is further provided in the embodiment of the present application, and fig. 12 is a schematic diagram of a system functional module of the wafer inspection system provided in the embodiment of the present application, where the wafer inspection method may be implemented, and the wafer inspection system includes:

the moving module 801 is configured to move a target die in a wafer to a preset target detection position, and sequentially collect images of the wafer at different heights of the target detection position, so as to obtain a die image including the target die at a corresponding height.

The first processing module 802 is configured to extract, for a grain image acquired at each height, image feature values of a plurality of pixel points in the grain image, and determine a peak feature from the plurality of image feature values.

The second processing module 803 is configured to establish a peak change curve based on peak features corresponding to the grain images acquired at different heights, and extract a height value corresponding to a vertex position in the peak change curve, so as to obtain a target height value.

The result module 804 is configured to determine that the corresponding target die is a die with abnormal placement if the target height value is not within the preset height threshold range.

As illustrated in fig. 5, fig. 5 is a schematic diagram of an optional conventional peak change curve of the wafer inspection method according to the embodiment of the present application, where the z-coordinate corresponds to a shooting height value of the image capturing device, and GMAX corresponds to a peak feature of a die image captured at each shooting height value, and the conventional peak change curve shown in fig. 5 is drawn according to the peak feature, where the curve represents a change condition of the peak feature of the die image corresponding to the wafer with the height of the image capturing device under the condition that no stacking or standing of the wafer is present; as shown in fig. 6, fig. 6 is a schematic diagram of an abnormal peak change curve of an alternative wafer inspection method according to an embodiment of the present application, and a curve drawing method similar to a conventional peak change curve may obtain an abnormal peak change curve, where the curve represents a change condition of peak characteristics of a corresponding die image of a wafer with the height of an image capturing device under a situation that a wafer is stacked or standing. It can be found that the curve generated when the abnormal die exists (i.e. stacked die or standing die) on the wafer has a peak difference from the curve generated when the abnormal die does not exist on the wafer, that is, the conventional peak change curve is taken as a reference curve, and if the curve drawn according to the die image corresponding to the currently detected wafer is inconsistent with the peak of the conventional peak change curve, it can be determined that the abnormal die exists on the target detection position on the wafer.

The specific implementation of the wafer inspection system is substantially the same as the specific embodiment of the wafer inspection method described above, and will not be described herein. On the premise of meeting the requirements of the embodiment of the application, the wafer detection system can be further provided with other functional modules so as to realize the wafer detection method in the embodiment.

The embodiment of the application also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and the processor realizes the wafer detection method when executing the computer program. The electronic equipment can be any intelligent terminal including a tablet personal computer, a vehicle-mounted computer and the like.

As shown in fig. 13, fig. 13 is a schematic hardware structure of an electronic device provided in an embodiment of the present application, where the electronic device includes:

The processor 901 may be implemented by a general purpose CPU (central processing unit), a microprocessor, an application specific integrated circuit (ApplicationSpecificIntegratedCircuit, ASIC), or one or more integrated circuits, etc. for executing related programs to implement the technical solutions provided by the embodiments of the present application;

the memory 902 may be implemented in the form of read-only memory (ReadOnlyMemory, ROM), static storage, dynamic storage, or random access memory (RandomAccessMemory, RAM). The memory 902 may store an operating system and other application programs, and when the technical solutions provided in the embodiments of the present application are implemented by software or firmware, relevant program codes are stored in the memory 902, and the processor 901 invokes the wafer inspection method to execute the embodiments of the present application;

an input/output interface 903 for inputting and outputting information;

the communication interface 904 is configured to implement communication interaction between the present device and other devices, and may implement communication in a wired manner (such as USB, network cable, etc.), or may implement communication in a wireless manner (such as mobile network, WI F I, bluetooth, etc.);

A bus 905 that transfers information between the various components of the device (e.g., the processor 901, the memory 902, the input/output interface 903, and the communication interface 904);

wherein the processor 901, the memory 902, the input/output interface 903 and the communication interface 904 are communicatively coupled to each other within the device via a bus 905.

The embodiment of the application also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the wafer detection method when being executed by a processor.

The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the processor, the remote memory being connectable to the processor through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The embodiments described in the embodiments of the present application are for more clearly describing the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application, and as those skilled in the art can know that, with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

It will be appreciated by those skilled in the art that the technical solutions shown in the figures do not constitute limitations of the embodiments of the present application, and may include more or fewer steps than shown, or may combine certain steps, or different steps.

The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Those of ordinary skill in the art will appreciate that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof.

The terms "first," "second," "third," "fourth," and the like in the description of the present application and in the above-described figures, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It should be understood that in this application, "at least one (item)" and "a number" mean one or more, and "a plurality" means two or more. "and/or" for describing the association relationship of the association object, the representation may have three relationships, for example, "a and/or B" may represent: only a, only B and both a and B are present, wherein a, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b or c may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

In the several embodiments provided in this application, it should be understood that the disclosed systems and methods may be implemented in other ways. For example, the system embodiments described above are merely illustrative, e.g., the division of the above elements is merely a logical functional division, and there may be additional divisions in actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in part or all of the technical solution or in part in the form of a software product stored in a storage medium, including multiple instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the various embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing a program.

Preferred embodiments of the present application are described above with reference to the accompanying drawings, and thus do not limit the scope of the claims of the embodiments of the present application. Any modifications, equivalent substitutions and improvements made by those skilled in the art without departing from the scope and spirit of the embodiments of the present application shall fall within the scope of the claims of the embodiments of the present application.

Claims

1. A method of wafer inspection, the method comprising:

2. The method according to claim 1, further comprising, after the determining that the corresponding target die is a die with abnormal placement:

3. The method for inspecting a wafer according to claim 2, wherein sequentially capturing images of the wafer at different heights of the target inspection position to obtain a die image including the target die at the corresponding height, comprises:

4. The method according to claim 3, wherein the extracting image feature values of a plurality of pixels in the die image for the die image acquired at each height and determining peak features from the plurality of image feature values comprises:

preprocessing the grain image to obtain a preprocessed grain image;

5. The method of claim 4, wherein if the target height value is not within a preset height threshold, determining that the corresponding target die is a die with abnormal placement comprises:

6. The method according to claim 5, further comprising, after the determining that the corresponding target die is a die with abnormal placement:

7. The wafer inspection method of claim 6, further comprising, after said determining the abnormal die coordinates of the target die:

acquiring a grain distribution diagram of the wafer;

8. A wafer inspection system, the system comprising:

9. An electronic device comprising a memory storing a computer program and a processor that when executing the computer program implements the wafer inspection method of any one of claims 1 to 7.

10. A computer readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the wafer inspection method of any one of claims 1 to 7.