Device for predicting wafer deformation

Abstract

The present disclosure provides, as one embodiment, a wafer deformation prediction device comprising: a transfer unit for transferring a wafer; a sensor unit for recognizing a plurality of edge points of the wafer being transferred by the transfer unit; and a control unit for projecting the positions of the plurality of edge points of the wafer recognized by the sensor unit onto a planar coordinate system and predicting the planar shape of the wafer based on the positions of the plurality of edge points of the wafer projected onto the planar coordinate system.

Description

Technology Field

[0001] The present disclosure relates to a wafer deformation prediction device. Background Technology

[0002] During the semiconductor chip manufacturing process, wafers may experience deformations such as bowing and warping due to factors like temperature differences. When wafers are moved to a warping measurement facility to measure warping, significant Turn Around Time (TAT) is required for the wafers' movement, input, alignment, and measurement processes, which can lead to reduced productivity. While measuring warping in only a portion of the wafers could be considered as a way to minimize productivity loss, this approach cannot perfectly detect wafer deformation caused by warping, potentially leading to wafer fracture. If the equipment interior becomes contaminated by damaged wafers, production stoppages can have a significant impact on productivity. The problem to be solved

[0003] In one aspect, the present disclosure aims to provide a wafer deformation prediction device capable of predicting wafer deformation without increasing time and cost associated with additional processes.

[0004] In another aspect, the present disclosure aims to provide a wafer deformation prediction device capable of predicting deformation for all wafers and selectively introducing only the wafers that are not deformed into the process.

[0005] In another aspect, the present disclosure aims to provide a wafer deformation prediction device capable of preventing wafer breakage and resulting equipment contamination. means of solving the problem

[0006] The present disclosure provides, as one embodiment, a wafer deformation prediction device comprising: a transfer unit for transferring a wafer; a sensor unit for recognizing a plurality of edge points of the wafer being transferred by the transfer unit; and a control unit for projecting the positions of the plurality of edge points of the wafer recognized by the sensor unit onto a planar coordinate system and predicting the planar shape of the wafer based on the positions of the plurality of edge points of the wafer projected onto the planar coordinate system.

[0007] The present disclosure provides, as another embodiment, a wafer deformation prediction device comprising: a transfer unit for transferring a wafer to a process chamber and returning the wafer released from the process chamber; a sensor unit for recognizing a plurality of pre-process edge points of the wafer during transfer of the wafer by the transfer unit and recognizing a plurality of post-process edge points of the wafer during return of the wafer by the transfer unit; and a control unit for projecting the positions of the plurality of pre-process edge points recognized by the sensor unit onto a planar coordinate system and predicting the pre-process planar shape of the wafer based on the positions of the plurality of pre-process edge points projected onto the planar coordinate system, and predicting the post-process planar shape of the wafer based on the positions of the plurality of post-process edge points recognized by the sensor unit and the positions of the plurality of post-process edge points projected onto the planar coordinate system.

[0008] The present disclosure provides a wafer deformation prediction device comprising, as another embodiment, a transfer unit that moves a wafer in a first direction, moves it in a second direction opposite to the first direction, and then transfers it in the first direction; a sensor unit that recognizes a plurality of first edge points of the wafer during the movement of the wafer in the first direction by the transfer unit, and recognizes a plurality of second edge points of the wafer during the movement of the wafer in the second direction by the transfer unit; and a control unit that projects the positions of the plurality of first edge points and the plurality of second edge points recognized by the sensor unit onto a planar coordinate system, and predicts the planar shape of the wafer based on the positions of the plurality of first edge points and the plurality of second edge points projected onto the planar coordinate system; wherein the wafer passes through the sensor unit during the movement in the first direction by the transfer unit and during the movement in the second direction by the transfer unit.

[0009] The present disclosure provides, as another embodiment, a wafer deformation prediction method comprising the steps of passing a wafer through a sensor unit, projecting the positions of a plurality of edge points of the wafer recognized by the sensor unit onto planar coordinates, and predicting the planar shape of the wafer based on the positions of the plurality of edge points of the wafer. Effects of the invention

[0010] According to one aspect of the present disclosure, a wafer deformation prediction device capable of predicting wafer deformation without increasing time and cost due to additional processes can be provided.

[0011] According to another aspect of the present disclosure, a wafer deformation prediction device can be provided that predicts deformation for all wafers and selectively feeds only the wafers that are not deformed into the process.

[0012] According to another aspect of the present disclosure, a wafer deformation prediction device capable of preventing wafer breakage and resulting equipment contamination can be provided. Brief explanation of the drawing

[0013] FIGS. 1 to 3 show examples of operation of a wafer deformation prediction device according to one embodiment. Figures 4 and 5 show the positions of edge points of the wafer projected onto planar coordinates. Figure 6 shows the predicted planar shape of the wafer and the derived exemplary characteristic values. FIGS. 7 and FIGS. 8 illustrate a method in which a sensor unit recognizes edge points of a wafer according to one embodiment. Figure 9 shows exemplary shapes of a wafer and their projection planes. FIG. 10 is a graph illustrating an exemplary method for predicting wafer deformation using a wafer deformation prediction device according to one embodiment. FIGS. 11 to 14 illustrate examples of the use of a wafer deformation prediction device according to one embodiment. FIGS. 15 and 16 illustrate examples of the use of a wafer deformation prediction device according to one embodiment. FIG. 17 is a flowchart of a method for predicting wafer deformation using a wafer deformation prediction device according to one embodiment. Specific details for implementing the invention

[0014] Hereinafter, various embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement them. The present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0015] To clearly explain the present disclosure, parts unrelated to the description have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0016] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present disclosure is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, in the drawings, the thickness of some layers and regions has been exaggerated for convenience of explanation.

[0017] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0018] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0019] Furthermore, throughout the specification, numbers such as "first," "second," etc., are used to distinguish a component from other components that are identical or similar, and are not intended to specifically refer to a particular component. Accordingly, a component referred to as the first component in a specific part of this specification may be referred to as the second component in another part of this specification.

[0020] Additionally, throughout the specification, a singular reference to any component includes a plural reference to such component unless specifically stated otherwise.

[0021] Hereinafter, a wafer deformation prediction device according to embodiments of the present disclosure will be described with reference to the drawings.

[0022] FIGS. 1 to 3 show examples of operation of a wafer deformation prediction device according to one embodiment.

[0023] Figures 4 and 5 show the positions of edge points of the wafer projected onto planar coordinates.

[0024] Figure 6 shows the predicted planar shape of the wafer and the derived exemplary characteristic values.

[0025] FIGS. 7 and FIGS. 8 illustrate a method in which a sensor unit recognizes edge points of a wafer according to one embodiment.

[0026] A wafer deformation prediction device (100) according to one embodiment can predict deformation of a wafer (10). For example, the wafer deformation prediction device (100) can predict whether the wafer (10) is deformed, the deformed shape, feature values, etc.

[0027] A wafer deformation prediction device (100) according to one embodiment includes a transfer unit (110), a sensor unit (120), and a control unit (130).

[0028] The transfer unit (110) transfers the wafer (10) and can pass the wafer (10) through the sensor unit (120) during transfer. Additionally, the transfer unit (110) can transfer the wafer (10) that has passed through the sensor unit (120) to a process chamber and return the wafer (10) released from the process chamber. The transfer unit (110) may transfer the wafer (10) directly to the process chamber and return it from the process chamber, or it may transfer the wafer (10) to the process chamber and return it from the process chamber via another component (e.g., another chamber).

[0029] The transfer unit (110) may be located, for example, between the Equipment Front End Module (EFEM) and the load lock, between the load lock and the transfer module, and between the transfer module and the process chamber. The EFEM may perform the role of loading and aligning the wafer (10). The load lock may perform the role of changing or adjusting the air pressure to a vacuum state between the EFEM and the transfer module. The transfer module may perform the role of transferring the wafer (10) to the process chamber, transferring it between process chambers, and returning the wafer (10) after the process is completed to the load lock. In the process chamber, the necessary process is performed on the wafer (10), and the process chamber may be a chamber in which substantial deformation (warpage) occurs on the wafer (10) due to temperature changes within the process chamber, temperature changes between process chambers, etc.

[0030] The transfer unit (110) may include a robot arm. However, the transfer unit (110) may include other transfer devices such as a rail.

[0031] The sensor unit (120) can recognize a plurality of edge points (a1, a2, a3, a4) of the wafer (10). The sensor unit (120) can recognize at least three edge points of the wafer (10) to predict the planar shape of the wafer (10). In this disclosure, the term "form" is used to include both shape and size.

[0032] The sensor unit (120) may be located in the movement path of the wafer (10) by the transfer unit (110). Like the transfer unit (110), the sensor unit (120) may be located in at least one of the following: between the Equipment Front End Module (EFEM) and the load lock, between the load lock and the transfer module, and between the transfer module and the process chamber.

[0033] In one embodiment, the position of the sensor unit (120) may be fixed, and the sensor unit (120) may be moved by the transfer unit (110) while in a fixed state and may recognize edge points of the wafer (10) passing through the sensor unit (120). However, the sensor unit (120) may also be moved to pass the wafer (10) in a fixed state and may recognize edge points of the wafer (10).

[0034] In one embodiment, the sensor unit (120) may include a first sensor unit (120A) and a second sensor unit (120B) spaced apart in a direction intersecting the Y direction (Y), which is the transport direction of the wafer (10), such as in the X direction (X) perpendicular to the Y direction (Y). The first sensor unit (120A) passes through the first sensor unit (120A) and can recognize a first edge point (a1) and a fourth edge point (a4) spaced apart in the Y direction (Y) of the wafer (10). The second sensor unit (120B) passes through the second sensor unit (120B) and can recognize a second edge point (a2) and a third edge point (a3) ​​spaced apart in the Y direction (Y) of the wafer (10). The first virtual line (VL1) extending from the first edge point (a1) and the fourth edge point (a4), and the second virtual line (VL2) connecting the second edge point (a2) and the third edge point (a3) ​​can each be extended in the Y direction (Y). The first virtual line (VL1) and the second virtual line (VL2) can be spaced apart in the X direction (X) and can be parallel. As the first sensor unit (120A) and the second sensor unit (120B) are fixed, the distance between the first virtual line (VL1) and the second virtual line (VL2) can be fixed.

[0035] Referring to FIGS. 7 and 8, the sensor unit (120) may include a light transmitter (121) that transmits light and a light receiver (122) that receives light transmitted from the light transmitter (121). The sensor unit (120) may recognize a plurality of edge points (a1, a2, a3, a4) of the wafer (10) based on whether the light receiver (122) receives light depending on whether the wafer (10) exists between the light transmitter (121) and the light receiver (122). When the wafer (10) does not exist between the light transmitter (121) and the light receiver (122), the light receiver (122) may receive light transmitted from the light transmitter (121) (see FIG. 7). When a wafer (10) exists between the light transmitter (121) and the light receiver (122), the light receiver (122) cannot receive light transmitted from the light transmitter (121) (see FIG. 8). The sensor unit (120) can output a digital signal value indicating whether the light receiver (122) receives light. For example, if the light receiver (122) receives light transmitted from the light transmitter (121), it can output a digital signal 1, and if it does not receive light, it can output a digital signal 0.

[0036] However, the sensor unit (120) may be composed of a different type of sensor capable of recognizing edge points (a1, a2, a3, a4) of the wafer (10). Alternatively, the sensor unit (120) may be configured to recognize the location of the edge points (a1, a2, a3, a4) of the wafer (10).

[0037] The control unit (130) can receive a signal output by the sensor unit (120). The control unit (130) projects the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) recognized by the sensor unit (120) onto a planar coordinate system, and can predict the planar shape of the wafer (10) based on the projected positions of the plurality of edge points (a1, a2, a3, a4) of the wafer (10).

[0038] In one embodiment, the control unit (130) can project the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) onto planar coordinates within the control unit (130) using data including at least one of the moving speed and moving trajectory of the wafer (10) along with the time when the sensor unit (120) recognizes the edge points (a1, a2, a3, a4) of the wafer (10). The time when the sensor unit (120) recognizes the edge points (a1, a2, a3, a4) of the wafer (10) may correspond to the time when the sensor unit (120) outputs a signal (e.g., a digital signal 0 or 1). For example, when the wafer (10) moves in a straight line along the Y direction (Y), the control unit (130) can project the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) onto a planar coordinate system using the output time of each signal output by the sensor unit (120) and the movement speed of the wafer (10). As another example, when the wafer (10) does not move in a straight line, the control unit (130) can project the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) onto a planar coordinate system using the output time of each signal output by the sensor unit (120), the movement speed of the wafer (10), and the movement trajectory.

[0039] In one embodiment, the control unit (130) can predict the planar shape of the wafer (10) by circle interpolation based on the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10). For example, the control unit (130) can predict the planar shape of the wafer (10) by circle interpolation based on the positions of three or four edge points (a1, a2, a3, a4) of the wafer (10) (e.g., in the case of an isotropic circular wafer).

[0040] In one embodiment, the control unit (130) can predict the planar shape of the wafer (10) by closed loop interpolation based on the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10). For example, the control unit (130) can predict the planar shape of the wafer (10) by closed loop interpolation based on the positions of four or more edge points (a1, a2, a3, a4) of the wafer (10).

[0041] Furthermore, the control unit (130) can extract characteristic values ​​of the wafer (10) from the predicted planar shape of the wafer (10). For example, the control unit (130) can derive the radius of the wafer (10) from the planar shape of the wafer (10) predicted by circular interpolation. Alternatively, the control unit (130) can derive at least one of the length of the major axis and the length of the minor axis of the wafer (10) from the planar shape of the wafer (10) predicted by closed-curve interpolation.

[0042] If height data at each point of the wafer (10) can be additionally input to the control unit (130), the control unit (130) may predict the three-dimensional shape of the wafer (10) by combining the height data at each point of the wafer (10) with the predicted planar shape.

[0043] If necessary, the control unit (130) may perform an additional function of aligning the wafer (10) based on the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10). That is, the control unit (130) may predict deformation of the wafer (10) based on the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) and simultaneously perform alignment of the wafer (10).

[0044] An example of the operation of the wafer deformation prediction device (100) during the transfer of the wafer (10) is described step-by-step as follows. First, referring to FIGS. 1 and 2, the wafer (10) is transferred by the transfer unit (110), the first edge point (a1) passes through the first sensor unit (120A), and the second edge point (a2) passes through the second sensor unit (120B). The control unit (130) projects the positions of the first edge point (a1) and the second edge point (a2) onto a planar coordinate system (see FIG. 4). For example, the control unit (130) can set the first edge point (a1) as a reference point (the location of the reference point in the drawing is shown differently from the origin), set the X coordinate of the second edge point (a2) (coordinate in the X direction (X)) through the gap between the fixed first virtual line (VL1) and the second virtual line (VL2) (which may correspond to the gap between the light transmitted from the first sensor unit (120A) and the second sensor unit (120B)), and set the Y coordinate of the third edge point (a3) ​​(coordinate in the Y direction (Y)) through the digital signal 0 output time of each of the first sensor unit (120A) and the second sensor unit (120B) and the movement speed of the wafer (10). Next, referring to FIG. 3, the third edge point (a3) ​​of the wafer (10) passes through the second sensor unit (120B), and the fourth edge point (a4) passes through the first sensor unit (120A). The control unit (130) projects the positions of the third edge point (a3) ​​and the fourth edge point (a4) onto a planar coordinate system (see FIG. 5). For example, the control unit (130) can set the X coordinate of the third edge point (a3) ​​to be the same as that of the second edge point (a2), and set the Y coordinate of the third edge point (a3) ​​through the duration of the digital signal 0 of the second sensor unit (120B) (the time taken for the digital signal 1 to be output again after the digital signal 0 is output) and the movement speed of the wafer (10).Additionally, the control unit (130) can set the X coordinate of the fourth edge point (a4) to be the same as the first edge point (a1), and set the Y coordinate of the fourth edge point (a4) through the digital signal 0 duration of the first sensor unit (120A) and the movement speed of the wafer (10). Next, referring to FIG. 6, the control unit (130) can predict the planar shape of the wafer (10) by circular interpolation based on the positions of a plurality of edge points (a1, a2, a3, a4) and derive the radius (R) of the wafer (10) as a characteristic value.

[0045] Meanwhile, deformations such as bowing and warping (warping) may occur in the wafer (10). When the wafer is moved to a warping measurement facility to measure the warping of the wafer, a large amount of TAT (Turn Around Time) is required depending on the wafer's movement, input, alignment, and measurement, which may cause a decrease in productivity. As a measure to minimize the decrease in productivity, one may consider measuring the warping of only some of the wafers, but in this case, the deformation of the wafers caused by warping cannot be perfectly detected, and thus, a fracture of the wafer may occur. If the inside of the facility is contaminated by a broken wafer, it may have a significant impact on productivity due to production stoppage.

[0046] According to the present disclosure, deformation of the wafer (10) can be predicted in real time by simply passing the wafer (10) through the sensor unit (120) while proceeding with the existing process, without the additional process of inserting and aligning the wafer (10) into a separate device and measuring warpage. Therefore, deformation of the wafer (10) can be predicted without increasing time and cost due to additional processes.

[0047] In addition, according to the present disclosure, the deformation of all wafers (10) can be predicted before the wafers (10) are introduced into the process chamber, and it can be determined whether to introduce the wafers (10) into a subsequent process based on whether each wafer (10) is deformed, the degree of deformation, etc. By selectively introducing the wafers (10) into a subsequent process based on the degree of deformation, damage to the wafers (10) can be prevented, and contamination inside the equipment and production stoppage caused by damaged wafers can be prevented.

[0048] In addition, the present disclosure can also be utilized to predict the shape of the wafer (10) from which the data is output by learning the data of the wafer (10) having a specific shape (e.g., the position of edge points in planar coordinates, the predicted planar shape, characteristic values, etc.) through machine learning.

[0049] Figure 9 shows exemplary shapes of a wafer and their projection planes.

[0050] Before deformation, the wafer may have a circular plate shape. During the process, deformation (warpage) occurs in the wafer due to bending and twisting. For example, the wafer may be deformed into various shapes, such as the saddle shape shown in Deformation Example 1, the dome shape shown in Deformation Example 2, the bowl shape shown in Deformation Example 3, the smile shape with both sides raised, and the crying shape with both sides lowered. When the wafer is deformed into a saddle shape, its projected plane appears elliptical, and when it is deformed into a dome or bowl shape, its projected plane appears as a reduced circle. According to the present disclosure, the deformation of the wafer can be predicted by utilizing the fact that different shapes (shapes and / or sizes) are displayed in the projected plane depending on the deformed shape.

[0051] FIG. 10 is a graph illustrating an exemplary method for predicting wafer deformation using a wafer deformation prediction device according to one embodiment.

[0052] The horizontal axis of the graph represents the track out time of each wafer (10) being released from the equipment, and the vertical axis represents the characteristic value of each wafer (10). A numerical characteristic value for the predicted planar shape of the wafer (10) can be loaded into the control unit (130). For example, the radius value of the wafer (10) can be loaded into the control unit (130). Since undeformed wafers exhibit similar characteristic values ​​and deformed wafers exhibit different values, deformed wafers can be detected by comparing the characteristic values ​​loaded into the control unit (130).

[0053] FIGS. 11 to 14 illustrate examples of the use of a wafer deformation prediction device according to one embodiment.

[0054] A wafer deformation prediction device according to one embodiment can be used to compare the shape of the wafer (10) before and after the process.

[0055] Figures 11 (a) to (f) show the wafer (10) passing through the sensor unit (120) during the transfer of the wafer (10) in stages.

[0056] FIG. 12 shows the predicted pre-process planar shape of the wafer (10) and the derived exemplary characteristic values.

[0057] Figures 13 (a) to (f) show the wafer (10) passing through the sensor unit (120) during wafer transport in stages.

[0058] FIG. 14 shows the predicted post-process planar shape of the wafer (10) and the derived exemplary characteristic values. The predicted pre-process planar shape is shown together with a dotted line for comparison with the wafer (10) before processing.

[0059] In FIGS. 11 and 13, the sensor unit (120) is shown with only the position (120p) in the Y direction (Y) of the sensor unit (120) as a dotted line. Also, the control unit (130) is omitted from the illustration.

[0060] As described above, the transfer unit (110) can transfer the wafer (10) to the process chamber and return it from the process chamber. During the transfer of the wafer (10), the wafer (10) is transferred in the Y direction (Y) and passes through the sensor unit (120), and during the return of the wafer (10), the wafer (10) is returned in the opposite direction of the Y direction (Y) (which may be referred to as the -Y direction (-Y) below) and passes through the sensor unit (120).

[0061] The sensor unit (120) can recognize multiple pre-process edge points (a1, a2, a3, a4) of the wafer (10) during transfer by the transfer unit (110), and recognize multiple post-process edge points (a1', a2', a3', a4') of the wafer (10) during return by the transfer unit (110).

[0062] In one embodiment, the sensor unit (120) can sequentially recognize the first edge point (a1), the second edge point (a2), the third edge point (a3), and the fourth edge point (a4) of the wafer (10) before processing during the transfer of the wafer (10) by the transfer unit (110), and sequentially recognize the fourth edge point (a4'), the third edge point (a3'), the second edge point (a2'), and the first edge point (a1') of the wafer (10) after processing during the return of the wafer (10) by the transfer unit (110).

[0063] The control unit (130) projects the positions of a plurality of pre-process edge points (a1, a2, a3, a4) recognized by the sensor unit (120) onto a planar coordinate system and can predict the pre-process planar shape of the wafer (10) based on the projected positions of the plurality of pre-process edge points (a1, a2, a3, a4). Additionally, the control unit (130) projects the positions of a plurality of post-process edge points (a1', a2', a3', a4') recognized by the sensor unit (120) onto a planar coordinate system and can predict the post-process planar shape of the wafer (10) based on the projected positions of the plurality of post-process edge points (a1', a2', a3', a4').

[0064] In one embodiment, the control unit (130) can predict the pre-process planar shape of the wafer (10) through four pre-process edge points (a1, a2, a3, a4) and predict the post-process planar shape of the wafer (10) through four post-process edge points (a1', a2', a3', a4'). For example, the control unit (130) can predict the pre-process or post-process planar shape of the wafer (10) by circular interpolation based on the positions of the pre-process or post-process edge points (a1, a2, a3, a4, a1', a2', a3', a4') of the wafer (10).

[0065] Furthermore, the control unit (130) can extract a pre-processing characteristic value and a post-processing characteristic value of the wafer (10) from the planar shape of the wafer (10) and / or compare the pre-processing characteristic value and the post-processing characteristic value. For example, the control unit (130) can extract and compare the pre-processing radius (R) and post-processing radius (R') of the wafer (10) from the planar shape of the wafer (10).

[0066] By comparing the shape of the wafer (10) before and after the process, the stress applied to the wafer (10) due to the process can be monitored, and the shape of the wafer (10) after the process can be predicted.

[0067] FIGS. 15 and 16 illustrate examples of the use of a wafer deformation prediction device according to one embodiment.

[0068] A wafer deformation prediction device according to one embodiment can be utilized for more sophisticated wafer deformation prediction. For example, the wafer deformation prediction device can be utilized for measuring anisotropic circular (e.g., elliptical) wafers.

[0069] Figures 15 (a) to (e) show the wafer (10) passing through the sensor unit (120) during the transfer of the wafer (10) in stages.

[0070] FIG. 16 shows the predicted planar shape of the wafer (10) and the derived exemplary characteristic values.

[0071] In FIG. 15, the sensor unit (120) is shown with only the position (120p) in the Y direction (Y) of the sensor unit (120) as a dotted line. Also, the control unit (130) is omitted from the illustration.

[0072] The transfer unit (110) can pass the wafer (10) through the sensor unit (120) multiple times. For example, the transfer unit (110) can move the wafer (10) in the Y direction (Y), move it in the -Y direction (-Y), and then transfer it again in the Y direction (Y). The wafer (10) can pass through the sensor unit (120) while moving in the Y direction (Y) and while moving in the -Y direction (-Y) by the transfer unit (110). Afterward, the transferred wafer (10) can be introduced into a process chamber. In this disclosure, the description is based on the wafer (10) transferred by the transfer unit (110) as an example, but it is obvious that the wafer returned by the transfer unit (110) can also be implemented to pass through the sensor unit (120) multiple times after being returned.

[0073] The transfer unit (110) may further move the wafer (10) after the sensor unit (120) recognizes the first edge points (a1, a2, a3, a4) and before the second edge points (b1, b2, b3, b4) so ​​that the sensor unit (120) recognizes the second edge points (b1, b2, b3, b4) which are distinct from the first edge points (a1, a2, a3, a4) while the wafer (10) is being transferred in the -Y direction (-Y). For example, the transfer unit (110) may move the wafer (10) in a direction intersecting the Y direction (Y), such as the X direction (X) perpendicular to the Y direction (Y). However, the transfer unit (110) may also move the wafer (10) in other ways, such as rotational movement, rotation and linear movement. If necessary, the transfer unit (110) may be fixed and the sensor unit (120) may be moved to recognize a plurality of second edge points (b1, b2, b3, b4) that are distinguished from a plurality of first edge points (a1, a2, a3, a4) while transferring the wafer (10) in the -Y direction (-Y).

[0074] Movement of the wafer (10) in the X direction (X) may be a movement for alignment of the wafer (10) during the process. For alignment of the wafer (10), the control unit (130) may derive a center position (e.g., center line (CL) or center point) of the wafer (10) in the X direction (X) based on the positions of a plurality of first edge points (a1, a2, a3, a4) recognized by the sensor unit (120). Subsequently, the transfer unit (110) may move the wafer (10) in the X direction (X) to move the derived center position of the wafer (10) to a preset alignment position (e.g., alignment line (AL) or alignment point) (see FIG. 15 (b) and (c)). For the transfer of the wafer (10), additional planar coordinates of the edge points may be obtained simultaneously with the alignment.

[0075] The sensor unit (120) can recognize a plurality of first edge points (a1, a2, a3, a4) of the wafer (10) while moving in the Y direction (Y) of the wafer (10), and recognize a plurality of second edge points (b1, b2, b3, b4) of the wafer (10) while moving in the opposite direction of the Y direction (Y) of the wafer (10). The first edge points (a1, a2, a3, a4) are edge points recognized primarily by the sensor unit (120), and the second edge points (b1, b2, b3, b4) are edge points recognized secondarily by the sensor unit (120).

[0076] In one embodiment, the sensor unit (120) can sequentially recognize the first-1 edge point (a1), the first-2 edge point (a2), the first-3 edge point (a3), and the first-4 edge point (a4) of the wafer (10) while moving the wafer (10) in the Y direction (Y). Additionally, while moving the wafer (10) in the -Y direction (-Y), the second-4 edge point (b4) and the second-3 edge point (b3) of the wafer (10) can be recognized simultaneously, and then the second-2 edge point (b2) and the second-1 edge point (b1) can be recognized simultaneously (when moving the wafer (10) in the -Y direction (-Y) after alignment).

[0077] The control unit (130) projects the positions of a plurality of first edge points (a1, a2, a3, a4) and a plurality of second edge points (b1, b2, b3, b4) recognized by the sensor unit (120) onto a planar coordinate system, and can predict the planar shape of the wafer (10) based on the projected positions of the plurality of first edge points (a1, a2, a3, a4) and a plurality of second edge points (b1, b2, b3, b4).

[0078] In one embodiment, the control unit (130) can predict the planar shape of the wafer (10) through four first edge points (a1, a2, a3, a4) and four second edge points (b1, b2, b3, b4). For example, the control unit (130) can predict the planar shape of the wafer (10) by closed curve interpolation based on the positions of a plurality of edge points (a1, a2, a3, a4, b1, b2, b3, b4) of the wafer (10).

[0079] Furthermore, the control unit (130) can extract characteristic values ​​of the wafer (10) from the predicted planar shape of the wafer (10). For example, the control unit (130) can derive at least one of the length of the major axis (L1) and the length of the minor axis (L2) of the wafer (10) from the planar shape of the wafer (10).

[0080] The deformation of the wafer (10) can be predicted more precisely based on the positions of multiple edge points (a1, a2, a3, a4, b1, b2, b3, b4).

[0081] FIG. 17 is a flowchart of a method for predicting wafer deformation using a wafer deformation prediction device according to one embodiment.

[0082] A wafer deformation prediction method according to the present disclosure comprises the steps of passing a wafer (10) through a sensor unit (120) (S11), projecting the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) recognized by the sensor unit (120) onto a planar coordinate system (S12), and predicting the planar shape of the wafer (10) based on the positions of the plurality of edge points (a1, a2, a3, a4) of the wafer (10) (S13).

[0083] In one embodiment, wafer deformation prediction can be performed after the wafer is introduced into the equipment and before the process is carried out. That is, wafer deformation prediction can be performed between the step of introducing the wafer into the equipment (S10) and the step of carrying out the process (S20). Accordingly, the process can be selectively carried out for each wafer depending on whether the wafer (10) is deformed, the degree of deformation, etc. After the step of completing the process (S30), the step of releasing the wafer (10) to the outside of the equipment (S40) can be performed.

[0084] In one embodiment, wafer deformation prediction may be performed at a stage between the first process and the second process, and the second process may be performed only on wafers determined not to be deformed after the first process. In another embodiment, wafer deformation prediction may be performed before and after the first process, respectively, and the stress applied to the wafer due to the first process may be monitored, and the deformation of the wafer according to the first process may be predicted.

[0085] In one embodiment, the step (S13) of predicting the planar shape of the wafer based on the positions of a plurality of edge points (a1, a2, a3, a4) of the wafer (10) can be performed by circular interpolation or closed-curve interpolation.

[0086] In one embodiment, a step (S14) of extracting characteristic values ​​of the wafer (10) from the predicted planar shape of the wafer (10) may be additionally performed. For example, in the step (S14) of extracting characteristic values ​​of the wafer (10), the radius of the wafer (10) may be derived as a characteristic value from the planar shape of the wafer (10), or at least one of the length of the major axis and the length of the minor axis may be derived as a characteristic value.

[0087] Furthermore, a step (S15) of loading characteristic values ​​of the wafer (10) may be additionally performed. Since undeformed wafers exhibit similar characteristic values ​​and deformed wafers exhibit different values, deformed wafers can be detected by comparing the loaded characteristic values.

[0088] Although embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims also fall within the scope of the present disclosure.

[0089] Furthermore, the embodiments of the present disclosure are not independent of one another and may be combined with one another unless there is a particular contradiction. Accordingly, embodiments combining the embodiments of the present disclosure should also be considered to be included in the present disclosure. Explanation of the symbols

[0090] 100: Wafer deformation prediction device 110: Transfer unit 120: Sensor section 121: Optical transmitter 122: Optical receiver 130: Control unit

Claims

Claim 1 A wafer deformation prediction device comprising: a transfer unit for transferring a wafer; a sensor unit for recognizing a plurality of edge points of the wafer being transferred by the transfer unit; and a control unit for projecting the positions of the plurality of edge points of the wafer recognized by the sensor unit onto a planar coordinate system and predicting the planar shape of the wafer based on the positions of the plurality of edge points of the wafer projected onto the planar coordinate system. Claim 2 A wafer deformation prediction device according to claim 1, wherein the sensor unit comprises a first sensor unit and a second sensor unit spaced apart in a second direction intersecting with a first direction which is the transfer direction of the wafer by the transfer unit. Claim 3 A wafer deformation prediction device according to claim 1, wherein the sensor unit includes a light transmitter that transmits light and a light receiver that receives light transmitted from the light transmitter, and recognizes a plurality of edge points of the wafer based on whether the light receiver receives light according to whether a wafer exists between the light transmitter and the light receiver. Claim 4 A wafer deformation prediction device according to claim 1, wherein the control unit projects the positions of a plurality of edge points of the wafer onto the plane coordinates using data including the time when the sensor unit recognizes each of a plurality of edge points of the wafer and the moving speed of the wafer. Claim 5 A wafer deformation prediction device according to claim 1, wherein the control unit predicts the planar shape of the wafer by circle interpolation based on the positions of a plurality of edge points of the wafer. Claim 6 In claim 5, the wafer deformation prediction device, wherein the control unit derives the radius of the wafer from the predicted planar shape of the wafer. Claim 7 A wafer deformation prediction device according to claim 1, wherein the control unit predicts the planar shape of the wafer by closed-loop interpolation based on the positions of a plurality of edge points of the wafer. Claim 8 In claim 7, the wafer deformation prediction device, wherein the control unit derives at least one of the length of the major axis and the length of the minor axis of the wafer from the predicted planar shape of the wafer. Claim 9 A wafer deformation prediction device comprising: a transfer unit for transferring a wafer to a process chamber and returning the wafer released from the process chamber; a sensor unit for recognizing a plurality of pre-process edge points of the wafer during transfer of the wafer by the transfer unit and recognizing a plurality of post-process edge points of the wafer during return of the wafer by the transfer unit; and a control unit for projecting the positions of the plurality of pre-process edge points recognized by the sensor unit onto a planar coordinate system and predicting the pre-process planar shape of the wafer based on the positions of the plurality of pre-process edge points projected onto the planar coordinate system, and projecting the positions of the plurality of post-process edge points recognized by the sensor unit onto the planar coordinate system and predicting the post-process planar shape of the wafer based on the positions of the plurality of post-process edge points projected onto the planar coordinate system. Claim 10 A wafer deformation prediction device comprising: a transfer unit that moves a wafer in a first direction, moves it in a second direction opposite to the first direction, and then transfers it in the first direction; a sensor unit that recognizes a plurality of first edge points of the wafer while the wafer moves in the first direction by the transfer unit, and recognizes a plurality of second edge points of the wafer while the wafer moves in the second direction by the transfer unit; and a control unit that projects the positions of the plurality of first edge points and the plurality of second edge points recognized by the sensor unit onto a planar coordinate system, and predicts the planar shape of the wafer based on the positions of the plurality of first edge points and the plurality of second edge points projected onto the planar coordinate system; wherein the wafer passes through the sensor unit while moving in the first direction by the transfer unit and while moving in the second direction by the transfer unit.

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