KR-20260066859-A - System for multivision-based automatic alignment for prober

KR20260066859AKR 20260066859 AKR20260066859 AKR 20260066859AKR-20260066859-A

Abstract

An automatic alignment system according to one embodiment of the present invention comprises: a camera; an alignment moving unit that moves a wafer so that the wafer is aligned based on an acquired first source image and a second source image; and a control unit that controls the alignment moving unit. The camera is provided in a plurality of units and can acquire a second source image at once that can determine each marker position with respect to the x-axis and y-axis. By overcoming the limitations of an individual inspection method using a single camera-based stage movement, high-precision alignment work can be performed during wafer alignment.

Inventors

황태민
소재혁
이동현
강혜원

Assignees

한국전자기술연구원

Dates

Publication Date: 20260512
Application Date: 20241105

Claims (12)

A camera for acquiring a first source image of the surface of an initial wafer and a second source image of a pre-aligned wafer; An alignment moving unit that moves the wafer so that the wafer is aligned based on the acquired first source image and second source image; and The control unit includes a first source image obtained to determine a notch position regarding a notch of the wafer and firstly control an alignment movement unit to pre-align the wafer based on the notch position, and after the wafer is pre-aligned, determines a marker position of the pre-aligned wafer from a second source image of the pre-aligned wafer, compares the determination result regarding the marker position with a target image stored regarding the marker, and secondly controls an alignment movement unit to finely align the pre-aligned wafer based on the comparison result. The camera is, A multivision-based automatic alignment system for a prober, characterized by acquiring a second source image at once, which is provided in multiple numbers and can determine the position of each marker with respect to the x-axis and y-axis.
In claim 1, The camera is, A multi-vision-based automatic alignment system for a prober, characterized by four cameras installed in pairs on the x-axis and y-axis respectively to acquire information on straight lines of the x-axis and y-axis at once, so as to acquire a second source image capable of determining each marker position with respect to the x-axis and y-axis and to use it as data for correcting rotation angle and center point coordinates.
In claim 2, The control unit is, Before the wafer fine alignment operation, determine whether the center of the second source image acquired through each camera coincides with the center of each marker, and A multivision-based automatic alignment system for a prober, characterized by performing a physical adjustment operation on the installation position of each camera so that the center point of each marker aligns with the center of the second source image obtained according to the judgment result.
In claim 3, The control unit is, If the center of the second source image acquired through each camera for which physical adjustment has been completed coincides with the center of each marker, the coordinate values of the wafer stage are stored, and A multivision-based automatic alignment system for a prober characterized by extracting and storing a target image corresponding to a marker size from a second source image acquired through each camera after physical adjustment work for the installation location has been completed.
In claim 4, The alignment movement part is, It includes a rotating part that rotates the wafer; and The control unit is, A multi-vision-based automatic alignment system for a prober, characterized by comparing the judgment result of the above-mentioned marker position with a stored target image, recognizing the center coordinates of each marker, obtaining the rotation angle value of a virtual straight line between the center coordinates of each marker along the x-axis and y-axis, and determining the control value of the rotation part based on the obtained rotation angle value.
In claim 5, The control unit is, A multivision-based automatic alignment system for a prober, characterized by comparing line information of a virtual line along the x-axis with line information of a virtual line along the Y-axis to control a rotating part so that a pre-aligned wafer is finely aligned until both rotation angle values are within a preset allowable tolerance, or determining a control value of the rotating part based on the average value of the two rotation angle values.
In claim 5, The control unit is, A multivision-based automatic alignment system for a prober, characterized by setting a limit on the control value of the rotating part so that, when controlling the rotating part, the amount of computation is reduced, and the pre-aligned wafer is finely aligned within a fine alignment rotation angle range having an absolute value smaller than the absolute value of the pre-alignment rotation angle range rotated when the wafer is pre-aligned.
In claim 7, The control unit is, A multivision-based automatic alignment system for a prober, characterized by controlling the rotating part to rotate the wafer by a set angle step within the fine alignment rotation angle range, so that when the wafer is pre-aligned, the pre-aligned wafer is finely aligned within the fine alignment rotation angle range having an absolute value smaller than the absolute value of the pre-alignment rotation angle range that is rotated when the wafer is pre-aligned.
In claim 1, The control unit is, A multivision-based automatic alignment system for a prober, characterized by including a Processing System (PS) that calculates a control value for rotating a wafer.
A wafer vision inspection method using a wafer vision inspection device comprising a camera, an alignment moving unit, and a control unit, wherein A step of acquiring a first source image of the surface of an initial wafer using a camera; A step of determining a notch position regarding a notch of the wafer from the first source image using a control unit, and first controlling an alignment movement unit so that the wafer is pre-aligned based on the notch position; A step of acquiring a second source image of the surface of a pre-aligned wafer using a camera; and The method includes the step of using a control unit to determine a marker position of a pre-aligned wafer from a second source image of the pre-aligned wafer, comparing the determination result for the marker position with a target image stored regarding the marker, and secondarily controlling an alignment movement unit so that the pre-aligned wafer is finely aligned based on the comparison result. The step of acquiring the second source image is, A multivision-based automatic alignment method for a prober, characterized by having multiple cameras provided to simultaneously acquire a second source image capable of determining each marker position with respect to the x-axis and y-axis.
A camera for acquiring a first source image of the surface of an initial wafer and a second source image of a pre-aligned wafer; An alignment moving unit that moves the wafer so that the wafer is aligned based on the acquired first source image and second source image; and A control unit comprising: determining a notch position regarding a notch of the wafer from an acquired first source image and first controlling an alignment moving unit so that the wafer is pre-aligned based on the notch position; and, after the wafer is pre-aligned, determining a marker position of the pre-aligned wafer from a second source image of the pre-aligned wafer, comparing the determination result regarding the marker position with a target image stored regarding the marker, and secondarily controlling an alignment moving unit so that the pre-aligned wafer is finely aligned based on the comparison result. The alignment movement part is, It includes a rotating part that rotates the wafer; and The control unit is, When comparing the judgment result regarding the above marker position with the stored target image, the center coordinates of each marker are recognized, and the rotation angle value of a virtual line between the center coordinates of each marker along the x-axis and y-axis is obtained, and A multivision-based automatic alignment system for a prober, characterized by determining the control value of the rotating part based on the acquired rotation angle value when the alignment moving part is secondarily controlled.
A wafer vision inspection method using a wafer vision inspection device comprising a camera, an alignment moving unit, and a control unit, wherein A step of acquiring a first source image of the surface of an initial wafer using a camera; A step of determining a notch position regarding a notch of the wafer from the first source image using a control unit, and first controlling an alignment movement unit so that the wafer is pre-aligned based on the notch position; A step of acquiring a second source image of the surface of a pre-aligned wafer using a camera; and The method includes the step of using a control unit to determine a marker position of a pre-aligned wafer from a second source image of the pre-aligned wafer, comparing the determination result for the marker position with a target image stored regarding the marker, and secondarily controlling an alignment movement unit so that the pre-aligned wafer is finely aligned based on the comparison result. The alignment movement part is, It includes a rotating part that rotates the wafer; and The step of secondarily controlling the alignment movement unit is, When comparing the judgment result regarding the above marker position with the stored target image, the center coordinates of each marker are recognized, and the rotation angle value of a virtual line between the center coordinates of each marker along the x-axis and y-axis is obtained, and A multivision-based automatic alignment method for a prober characterized by determining the control value of a rotating part based on an acquired rotation angle value when a moving alignment part is secondarily controlled.

Description

System for multivision-based automatic alignment for prober The present invention relates to an automatic alignment system for wafers, and more specifically, to an automatic alignment system based on vision information for a probe. Generally, the semiconductor manufacturing process includes a vision inspection (appearance inspection) process for a wafer with a circuit pattern formed on its surface. In particular, for vision alignment technology used for fine alignment between probes and pads in prober equipment required for inspecting the electrical characteristics of wafers in the semiconductor back-end process, the control unit performing various calculations is implemented using a general PC processor. To improve alignment performance, such vision alignment technology requires the development of methods capable of recognizing multiple alignment marks more quickly and accurately in batches and correcting misalignment. FIG. 1 is a drawing provided for the description of the configuration of a multivision-based automatic alignment system for a prober according to an embodiment of the present invention. FIG. 2 is a drawing provided for a more detailed configuration description of the alignment moving part illustrated in FIG. 1. FIG. 3 is a drawing provided for a more detailed configuration description of the control unit illustrated in FIG. 1. FIG. 4 is a drawing illustrating a wafer with marker positions marked thereon to show an example of fine alignment performed through an automatic alignment system according to an embodiment of the present invention. FIG. 5 is a flowchart provided to explain the process of extracting and storing target images corresponding to each marker through an automatic alignment system according to an embodiment of the present invention. FIG. 6 is a flowchart provided for explaining an automatic alignment method according to an embodiment of the present invention, FIG. 7 is a flowchart provided for explaining the process of determining a control value of a rotating part for wafer fine alignment through an automatic alignment system according to an embodiment of the present invention, and FIG. 8 is a diagram illustrating wafer fine alignment being performed through an automatic alignment system according to one embodiment of the present invention. The present invention will be described in more detail below with reference to the drawings. To clearly explain the invention, parts unrelated to the description have been omitted from the drawings, and in the drawings, the width, length, thickness, etc., of the components may be exaggerated for convenience. FIG. 1 is a drawing provided to describe the configuration of a multivision-based automatic alignment system for a prober according to one embodiment of the present invention. A multivision-based automatic alignment system for a prober according to the present embodiment (hereinafter collectively referred to as the 'automatic alignment system') may include one or more cameras (100), an alignment moving unit (200), a control unit (300), and a storage unit (400), as shown in FIG. 1. A camera (100) is provided to acquire a first source image of the surface of an initial wafer and a second source image of a pre-aligned wafer. For example, when a plurality of markers are formed on a wafer, the camera (100) is provided in multiple units (operated in multiple channels) and can acquire a second source image at once that can determine the position of each marker with respect to the x-axis and y-axis. Specifically, when a plurality of markers are formed on a wafer as exemplified in FIG. 4, four cameras are installed in pairs on the x-axis and y-axis respectively to acquire a second source image capable of determining the position of each marker with respect to the x-axis and y-axis and to use it as data for correcting the rotation angle and center point coordinates, so that the control unit (300) can acquire information on the straight line of the x-axis and y-axis at once. That is, four cameras (100) are installed on the left side of the x-axis, the right side of the x-axis, the left side of the y-axis, and the right side of the y-axis, respectively, so that a second source image is acquired from the left side of the x-axis, the right side of the x-axis, the left side of the y-axis, and the right side of the y-axis, respectively, so that the control unit (300) can acquire information on the x-axis virtual line and information on the y-axis virtual line at once. The alignment moving unit (200) can move the wafer so that the wafer is aligned based on the acquired first source image and second source image. The storage unit (400) is a storage medium for storing programs and data necessary for the operation of the control unit (300). The control unit (300) is provided to handle all matters for aligning the wafer based on the source image. For example, the control unit (300) can determine the notch position regarding the notch of the wafer from the