CN117168320A - Calibration method and device for horizontal zero position of mask table and electronic equipment - Google Patents
Calibration method and device for horizontal zero position of mask table and electronic equipment Download PDFInfo
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Abstract
The application provides a method and a device for calibrating a horizontal zero position of a mask table and electronic equipment, wherein the method comprises the following steps: controlling the movable workbench to perform spiral search, aligning the image alignment mark with a grating image, and recording the alignment position corresponding to the movable workbench; constructing a loss function according to the grating group position of the grating group to which the grating image corresponding to each measurement belongs on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench obtained by each measurement and the horizontal zero offset corresponding to the mask table; iteratively calculating a loss function by using a gradient descent method, and determining a target horizontal zero offset corresponding to the mask table; and according to the nominal zero position of the mask table and the target horizontal zero position deviation, the calibration of the horizontal zero position of the mask table is completed. According to the application, the mask table reference plate and the workpiece table reference plate are used for completing the calibration of the horizontal zero position of the mask table, so that the calibration steps are simplified, the calibration cost is reduced, and the calibration efficiency is improved.
Description
Technical Field
The present application relates to the field of optical detection technologies, and in particular, to a method and an apparatus for calibrating a horizontal zero position of a mask stage, and an electronic device.
Background
Along with the continuous improvement of the production precision requirement of the measuring equipment, the early calibration of the hardware of the equipment is very important, and in order to improve the interlayer alignment precision, the position relation between the mask and the wafer needs to be established, so that the calibration of the zero position of the mask stage needs to be determined.
At present, the calibration of the horizontal zero position of a mask table usually needs to remove the external protection of equipment, pins are inserted into round holes fixed on the mask table, then a special mask is abutted against the pins, and the measurement is carried out by utilizing the holes on the mask, but in the actual calibration process, the removal of the external protection of the equipment and the installation of the pins are complicated, so that the calibration process is low in efficiency, and the corresponding Dev mask is required to be customized for mask tables with different sizes, so that the calibration cost is increased.
Disclosure of Invention
Therefore, the application aims to provide at least a method, a device and an electronic device for calibrating the horizontal zero position of a mask table, and the calibration of the horizontal zero position of the mask table is completed by using a mask table reference plate and a workpiece table reference plate, so that the calibration steps are simplified, the calibration cost is reduced, and the calibration efficiency is improved.
The application mainly comprises the following aspects:
in a first aspect, an embodiment of the present application provides a method for calibrating a horizontal zero position of a mask stage, which is applied to a measurement system, where the measurement system includes a light source, a mask stage, an objective lens, and a movable table, a mask reference plate is fixed on the mask stage, a plurality of grating groups are formed on the mask reference plate, a table reference plate is fixed on the movable table, and an image alignment mark is formed on the table reference plate, where the method includes: turning on a light source, wherein light emitted by the light source passes through a plurality of grating groups and an objective lens, and a grating image corresponding to each grating group is formed on a workbench reference plate; controlling the movable stage to move to perform a plurality of measurements, during each measurement: controlling the movable workbench to perform spiral search, aligning the image alignment mark with a grating image, and recording the alignment position corresponding to the movable workbench; constructing a loss function according to the grating group position of the grating group to which the grating image corresponding to each measurement belongs on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench obtained by each measurement and the horizontal zero offset corresponding to the mask table; iteratively calculating a loss function by using a gradient descent method, and determining a target horizontal zero offset corresponding to the mask table; and according to the nominal zero position of the mask table and the target horizontal zero position deviation, the calibration of the horizontal zero position of the mask table is completed.
In one possible embodiment, each grating group includes an X-direction grating and a Y-direction grating, the image alignment mark includes an X-direction alignment mark and a Y-direction alignment mark, the grating image includes an X-direction grating image and a Y-direction grating image, and the alignment position includes an X-alignment coordinate and a Y-alignment coordinate corresponding to the movable stage, wherein the alignment position corresponding to the movable stage during each measurement is determined by: during this measurement, the following process is performed: controlling the light source to move above the target grating group so as to form an X-direction grating image and a Y-direction grating image on the workbench reference plate; the movable workbench is controlled to perform spiral search according to a preset unit step length, and the X-direction grating overlapping rate between the X-direction grating image fed back by the X-direction alignment mark and the Y-direction grating overlapping rate between the Y-direction grating image fed back by the Y-direction alignment mark and the Y-direction alignment mark are respectively obtained when one preset unit step length is moved; and determining the X alignment coordinate and the Y alignment coordinate corresponding to the measurement according to the X-direction grating overlapping rate and the Y-direction grating overlapping rate corresponding to each movement of the movable workbench.
In one possible embodiment, the X and Y alignment coordinates corresponding to the movable stage during each measurement are determined by: during this measurement: determining an X coordinate of the movable workbench corresponding to the maximum X-direction grating overlapping rate as an X alignment coordinate; and determining the Y coordinate of the movable workbench corresponding to the maximum Y-direction grating overlapping rate as the Y alignment coordinate.
In one possible implementation, the grating group position includes an X-coordinate of the X-direction grating on the mask stage and a Y-coordinate of the Y-direction grating on the mask stage, the horizontal zero offset includes an X-direction zero offset, a Y-direction zero offset, and a rotation angle zero offset of a nominal zero relative to an actual zero corresponding to the mask stage, and the mark position includes an X-coordinate of the X-direction alignment mark on the movable stage and a Y-coordinate of the Y-direction alignment mark on the movable stage, wherein the loss function is constructed by the following formula:
in this formula, F (-) represents the loss function, n represents the total number of measurements, rz 0 For zero deviation of rotation angle, x pi Representing the X coordinate, y of the X-direction grating corresponding to the ith measurement on the mask stage pi Representing the Y coordinate of the Y-direction grating corresponding to the ith measurement on the mask stage; x is x 0 Is zero offset in X direction, y 0 Is zero offset in Y direction, x g Representing the X coordinate, y of the X direction alignment mark on the movable workbench g Representing the Y coordinate, x of the Y-direction alignment mark on the movable worktable si Representing the X alignment coordinate, y corresponding to the ith measurement si Indicating the Y-alignment coordinate corresponding to the ith measurement.
In one possible implementation, the step of iteratively calculating the loss function using a gradient descent method, and determining the target horizontal zero offset corresponding to the mask stage includes: (A) Determining a first partial guide expression of a loss function on zero offset in the X direction, a second partial guide expression of zero offset in the Y direction and a third partial guide expression of zero offset in the rotation angle respectively; (B) Substituting the current X-direction zero offset, the current Y-direction zero offset and the current rotation angle zero offset into a first partial guide expression, a second partial guide expression and a third partial guide expression respectively to obtain an X partial guide value corresponding to the first partial guide expression, a Y partial guide value corresponding to the second partial guide expression and a rotation angle partial guide value corresponding to the third partial guide expression; (C) Respectively updating the zero offset in the X direction, the zero offset in the Y direction and the zero offset in the rotation angle according to the calculated X partial guide value, the Y partial guide value and the rotation angle partial guide value; (D) Substituting the updated zero offset in the X direction, the updated zero offset in the Y direction and the updated zero offset in the rotation angle into a loss function, and calculating to obtain a loss value; (E) And comparing the loss value with a preset loss threshold value, and determining the target horizontal zero offset according to the comparison result.
In one possible embodiment, step (C) comprises: calculating a first product between the X-direction deviation value and the unit step length of the mask table, and determining the sum value between the first product and the current X-direction zero offset as updated X-direction zero offset; calculating a second product between the Y-direction deviation value and the unit step length of the mask table, and determining the sum value between the second product and the current Y-direction zero offset as updated Y-direction zero offset; and calculating a third product between the rotation angle deviation value and the unit step length of the mask table, and determining the sum value between the third product and the zero offset of the current rotation angle as the updated zero offset of the rotation angle.
In one possible embodiment, the target horizontal zero offset includes a target X-direction zero offset, a target Y-direction zero offset, and a target rotation angle zero offset, wherein step (E) includes: if the loss value is greater than or equal to the preset loss threshold value, returning to the step (B) by using the updated X deviation, Y deviation and rotation angle deviation; if the loss value is smaller than the preset loss threshold value, the updated X-direction zero offset, Y-direction zero offset and rotation angle zero offset are respectively determined to be the target X-direction zero offset, the target Y-direction zero offset and the target rotation angle zero offset.
In one possible implementation, the nominal zero position includes a nominal zero position X coordinate, a nominal zero position Y coordinate, and a nominal zero position rotation angle, wherein the step of completing calibration of the mask stage horizontal zero position according to the nominal zero position and the target horizontal zero position bias of the mask stage includes: determining the difference value between the nominal zero position X coordinate and zero position deviation in the X direction of the target as the actual zero position X coordinate corresponding to the mask table; determining the difference value between the nominal zero position Y coordinate and the zero position deviation of the target Y direction as the actual zero position Y coordinate corresponding to the mask table; determining the difference value between the nominal zero rotation angle and the zero deviation of the target rotation angle as the actual zero rotation angle corresponding to the mask table; and controlling the mask table to move to the positions indicated by the actual zero X coordinate, the actual zero Y coordinate and the actual zero rotation angle so as to finish the calibration of the horizontal zero of the mask table.
In a second aspect, an embodiment of the present application further provides a calibration apparatus for a horizontal zero position of a mask stage, which is applied to a measurement system, the measurement system including a light source, a mask stage, an objective lens, and a movable stage, a mask reference plate being fixed on the mask stage, a plurality of grating groups being formed on the mask reference plate, a stage reference plate being fixed on the movable stage, and an image alignment mark being formed on the stage reference plate, the apparatus comprising: the projection module is used for starting a light source, and light emitted by the light source passes through a plurality of grating groups and an objective lens to form grating images corresponding to each grating group on the workbench reference plate; a measurement module for controlling the movable table to move to perform a plurality of measurements, during each measurement: controlling the movable workbench to perform spiral search, aligning the image alignment mark with a grating image, and recording the alignment position corresponding to the movable workbench; the loss function construction module is used for constructing a loss function according to the grating group position of the grating group on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench and the horizontal zero offset corresponding to the mask table, which are obtained by each measurement; the determining module is used for iteratively calculating a loss function by using a gradient descent method and determining a target horizontal zero offset corresponding to the mask table; and the calibration module is used for completing the calibration of the horizontal zero position of the mask table according to the nominal zero position of the mask table and the target horizontal zero position deviation.
In a third aspect, an embodiment of the present application further provides an electronic device, including: the mask stage horizontal zero calibration method comprises the steps of a processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, when the electronic device runs, the processor and the memory are communicated through the bus, and the machine-readable instructions are executed by the processor to perform the steps of the mask stage horizontal zero calibration method in the first aspect or any possible implementation mode of the first aspect.
According to the calibration method and device for the horizontal zero position of the mask table and the electronic equipment, the movable workbench is controlled to perform spiral search, and after alignment of the grating image and the image alignment mark is achieved, the alignment position corresponding to the movable workbench is recorded; constructing a loss function according to the grating group position of the grating group on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench obtained by each measurement and the horizontal zero offset corresponding to the mask table; iteratively calculating a loss function by using a gradient descent method, and determining a target horizontal zero offset corresponding to the mask table; and according to the nominal zero position of the mask table and the target horizontal zero position deviation, the calibration of the horizontal zero position of the mask table is completed. According to the application, the mask table reference plate and the workpiece table reference plate are used for calibrating the horizontal zero position of the mask table, so that the external protection is not required to be disassembled and the special mask plate is not required to be loaded, the calibration step is simplified, and the calibration cost is reduced.
The application has the advantages that:
the mask table reference plate and the workpiece table reference plate are used for measurement, and the external protection and the loading of the special mask plate are not needed, so that the complexity of measurement and calibration is avoided, and the cost for manufacturing the special mask plate is reduced;
the zero offset of the mask table can be determined simply by aligning the marks on the two reference plates, and the mask table is convenient and quick.
In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a measurement system according to an embodiment of the present application;
FIG. 2 is a schematic diagram showing a structure of a mask reference plate relative to a mask stage according to an embodiment of the present application;
FIG. 3 is a flowchart of a method for calibrating a horizontal zero of a mask stage according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a movable table performing a spiral search according to an embodiment of the present application;
FIG. 5 is a flowchart showing steps of a target level zero bias determination method provided by an embodiment of the present application;
FIG. 6 shows a schematic structural diagram of a calibration device for horizontal zero of a mask stage according to an embodiment of the present application;
fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application, and it should be understood that the drawings in the present application are for the purpose of illustration and description only and are not intended to limit the scope of the present application. In addition, it should be understood that the schematic drawings are not drawn to scale. A flowchart, as used in this disclosure, illustrates operations implemented according to some embodiments of the present application. It should be appreciated that the operations of the flow diagrams may be implemented out of order and that steps without logical context may be performed in reverse order or concurrently. Moreover, one or more other operations may be added to or removed from the flow diagrams by those skilled in the art under the direction of the present disclosure.
In addition, the described embodiments are only some, but not all, embodiments of the application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art based on embodiments of the application without making any inventive effort, fall within the scope of the application.
At present, the calibration of the horizontal zero position of a mask table usually requires removing the external protection of equipment, inserting pins into round holes fixed on the mask table, then abutting a special mask against the pins, and measuring by using the holes on the mask.
However, in the actual calibration process, the outer protection of the equipment and the mounting pin are removed each time, which is complicated, and the calibration efficiency is low. And the original calibration method has the following disadvantages:
(1) the accuracy of the mask position depends on the position of the pin;
(2) the risk of wearing the mask plate is increased by manually uploading the mask plate, so that the calibration cost is increased, and the calibration accuracy is affected;
(3) because the size of the mask apertures mapped to the wafer surface is very small, it is difficult to find,
the calibration time is increased, and the calibration efficiency is reduced.
Based on the above, the embodiment of the application provides a method, a device and an electronic device for calibrating a horizontal zero position of a mask table, which are used for calibrating the horizontal zero position of the mask table by using a mask table reference plate and a workpiece table reference plate, so that the calibration steps are simplified, the calibration cost is reduced, and the calibration efficiency is improved, and the method comprises the following specific steps:
referring to fig. 1, fig. 1 is a schematic diagram illustrating a measurement system according to an embodiment of the application. Referring to fig. 2, fig. 2 is a schematic structural diagram of a mask reference plate relative to a mask stage according to an embodiment of the application.
As shown in fig. 1, the measuring system comprises a light source 1, a mask stage 2, an objective lens 3 and a movable working stage 4, wherein a mask reference plate 5 is fixed on the mask stage 2, the length of the mask reference plate 5 is smaller than the length of the mask stage 2, the width of the mask reference plate 5 is smaller than the width of the mask stage 2, and a plurality of grating groups a are formed on the mask reference plate as shown in fig. 2 1 ～a n N represents the number of grating groups, and a stage reference plate (not shown) on which an image alignment mark is formed is fixed to the movable stage 4.
Referring to fig. 3, fig. 3 is a flowchart illustrating a method for calibrating a horizontal zero position of a mask stage according to an embodiment of the present application. The method for calibrating the horizontal zero position of the mask table provided by the embodiment of the application, as shown in fig. 3, comprises the following steps:
s100, turning on a light source.
The light emitted from the light source 1 forms a grating image corresponding to each grating group a on the table reference plate via the plurality of grating groups a on the mask reference plate 5 and the objective lens 3.
S200, controlling the movable workbench to move to execute a plurality of measurements, wherein in each measurement process: and controlling the movable workbench to perform spiral search, enabling the image alignment mark to be aligned with a grating image, and recording the alignment position corresponding to the movable workbench.
S300, constructing a loss function according to the grating group position of the grating group to which the grating image corresponding to each measurement belongs on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench obtained by each measurement and the horizontal zero offset corresponding to the mask table.
S400, iteratively calculating a loss function by using a gradient descent method, and determining the target horizontal zero offset corresponding to the mask table.
S500, according to the nominal zero position of the mask table and the target horizontal zero position deviation, the calibration of the horizontal zero position of the mask table is completed.
In particular implementations, each grating set a includes an X-direction grating and a Y-direction grating, the image alignment marks include an X-direction alignment mark and a Y-direction alignment mark, and the grating images include an X-direction grating image and a Y-direction grating image, as shown in FIG. 1, in grating set a k For example, after the light source 1 is turned on, the light emitted by the light source 1 passes through the grating group a k The X-direction grating and the object lens 3 in the optical fiber form an X-direction grating image on a workbench reference plate, and the light emitted by the light source 1 passes through the grating group a k The Y-direction grating and the object lens 3 form a Y-direction grating image on the workbench reference plate, and the alignment position comprises an X alignment coordinate and a Y alignment coordinate corresponding to the movable workbench, and in the application, the grating image corresponding to the grating group can be selected according to actual requirements to perform measurement, for example, the distance on the mask reference plate can be selected to be the mostThe far two grating sets perform two measurements to complete the calibration.
In the present application, before step S200, it is necessary to control the mask stage to move to an initial position corresponding to the nominal zero position of the mask stage, and then execute step S200.
In a preferred embodiment, the alignment position of the movable table during each measurement is determined by: during this measurement, the following process is performed:
and controlling the movable workbench to perform spiral search according to a preset unit step length, respectively acquiring an X-direction grating overlapping rate between an X-direction grating image fed back by the X-direction alignment mark and a Y-direction grating overlapping rate between a Y-direction grating image fed back by the Y-direction alignment mark and the Y-direction alignment mark when moving by one preset unit step length, and determining an X-direction alignment coordinate and a Y-direction alignment coordinate corresponding to the measurement according to the X-direction grating overlapping rate and the Y-direction grating overlapping rate corresponding to each movement of the movable workbench.
In the present application, brightness sensors are disposed on the X-direction alignment mark and the Y-direction alignment mark, for obtaining the grating overlapping rate between the grating image passing through the objective lens and the alignment mark, please refer to fig. 4, fig. 4 shows a schematic diagram of spiral searching performed by a movable workbench according to an embodiment of the present application. As shown in fig. 4, the movable table starts from the preset initial position 0 according to the sequence of 0-M1-M2-M3-M4-M5-M6-M7-M8-M9-M10-M11-M12-M13, and performs spiral search along the horizontal XY direction, wherein during the search, each position is moved, the X-direction grating overlapping rate and the Y-direction grating overlapping rate need to be recorded, and the X-direction grating overlapping rate and the Y-direction grating overlapping rate obtained by each movement are determined according to the X-direction grating overlapping rate and the Y-direction grating overlapping rate obtained by each movement.
In another preferred embodiment, the X and Y alignment coordinates corresponding to the movable stage during each measurement are determined by:
during this measurement: and determining an X coordinate of the movable workbench corresponding to the maximum X-direction grating overlapping rate as an X alignment coordinate, and determining a Y coordinate of the movable workbench corresponding to the maximum Y-direction grating overlapping rate as a Y alignment coordinate.
As shown in fig. 4, in all of the search positions 0 to M13, if the M10 position has the maximum X-direction grating overlap ratio, the X coordinate corresponding to the M10 position is determined as the X alignment coordinate, and if the M7 position has the maximum Y-direction grating overlap ratio, the Y coordinate corresponding to the M7 position is determined as the Y alignment coordinate.
In step S300, the grating group position includes an X coordinate of the X-direction grating on the mask stage and a Y coordinate of the Y-direction grating on the mask stage, the horizontal zero offset includes an X-direction zero offset, a Y-direction zero offset, and a rotation angle zero offset of a nominal zero bit corresponding to the mask stage relative to an actual zero bit, and the mark position includes an X coordinate of the X-direction alignment mark on the movable table and a Y coordinate of the Y-direction alignment mark on the movable table.
In one possible implementation, for a single measurement, the following formula exists:
L·T 0 ·(P-t 0 )＝(G-s)(1)
in formula (1), T 0 Representing a mask table zero rotation matrix, wherein,after Taylor expansion, omit more than 2 nd order, simplify to get +.>Rz 0 To be calculated, the zero deviation of the rotation angle of the mask stage is expressed,
representing the position of the grating group corresponding to the grating group on the mask stage,x p representing the X-direction grating on the maskX coordinates, y on the table p Representing the Y coordinate of the Y-direction grating on the mask stage,
t 0 to be calculated, the xy component of zero bias corresponding to the mask stage is expressed,wherein x is 0 Represents zero offset in X direction and y corresponding to the mask stage 0 Represents the zero offset of the mask stage in the corresponding Y direction, S represents the table rotation matrix, wherein,r represents the horizontal rotation angle of the table, and in the present application, the movable table is not provided with rotation, i.e., r=0, and in this case, S is an identity matrix.
G is a machine constant, representing the position of the image alignment marks on the stage datum plate on the movable stage,x g representing the X coordinate, y of the X direction alignment mark on the movable workbench g Representing the Y coordinate of the Y-direction alignment mark on the movable stage.
L is a machine constant, represents the magnification of the objective lens, s is an alignment position corresponding to the movable worktable obtained in the spiral search,x s representing the X alignment coordinate, y determined by measurement s Representing the Y alignment coordinate determined by the measurement.
In a preferred embodiment, the formula (1) corresponds to a single measurement, but in the present application, a plurality of measurements are performed, and since L is a machine constant, this machine constant L is ignored this time, based on the above, the formula (1) is transformed, and the following loss function is obtained by fitting the formula by integrating the plurality of measurements:
in formula (2), F ()'s represent loss functions, n represents the total number of measurements, x pi Representing the X coordinate, y of the X-direction grating corresponding to the ith measurement on the mask stage pi Representing the Y coordinate of the Y-direction grating corresponding to the ith measurement on the mask stage, si representing the X alignment coordinate, y corresponding to the ith measurement si Indicating the Y-alignment coordinate corresponding to the ith measurement.
Referring to fig. 5, fig. 5 is a flowchart illustrating steps of a target horizontal zero offset determination method according to an embodiment of the present application. As shown in fig. 5, step S400 includes:
(A) And determining a first partial guide expression of the loss function on zero offset in the X direction, a second partial guide expression of the loss function on zero offset in the Y direction and a third partial guide expression of zero offset in the rotation angle respectively.
Specifically, the first partial guide expression is:
the second partial guide expression is:
the third partial conductance expression is:
(B) Substituting the current X-direction zero offset, the current Y-direction zero offset and the current rotation angle zero offset into a first partial guide expression, a second partial guide expression and a third partial guide expression respectively to obtain an X partial guide value corresponding to the first partial guide expression, a Y partial guide value corresponding to the second partial guide expression and a rotation angle partial guide value corresponding to the third partial guide expression.
In the present application, x is used when step (B) is performed for the first time 0 、y 0 And Rz 0 The corresponding preset initial values are used as the current zero position deviation in the X direction, the current zero position deviation in the Y direction and the current zero position deviation in the rotation angle, so that the updating of the zero position deviation in the X direction, the zero position deviation in the Y direction and the zero position deviation in the rotation angle is completed.
(C) And respectively updating the zero offset in the X direction, the zero offset in the Y direction and the zero offset in the rotation angle according to the calculated X partial guide value, the Y partial guide value and the rotation angle partial guide value.
In another preferred embodiment, step (C) comprises:
calculating a first product between the X-direction deviation value and the unit step length of the mask table, determining a sum value between the first product and the current X-direction zero deviation as updated X-direction zero deviation, calculating a second product between the Y-direction deviation value and the unit step length of the mask table, determining a sum value between the second product and the current Y-direction zero deviation as updated Y-direction zero deviation, calculating a third product between the rotation angle deviation value and the unit step length of the mask table, and determining a sum value between the third product and the current rotation angle zero deviation as updated rotation angle zero deviation.
(D) Substituting the updated zero offset in the X direction, the updated zero offset in the Y direction and the updated zero offset in the rotation angle into a loss function, and calculating to obtain a loss value.
(E) And comparing the loss value with a preset loss threshold value, and determining the target horizontal zero offset according to the comparison result.
Specifically, the target horizontal zero offset includes a target X-direction zero offset, a target Y-direction zero offset, and a target rotation angle zero offset, where step (E) includes:
and (C) if the loss value is greater than or equal to a preset loss threshold, returning to the execution step (B) by using the updated X-direction zero-position deviation, Y-direction zero-position deviation and rotation angle deviation, and if the loss value is less than the preset loss threshold, respectively determining the updated X-direction zero-position deviation, Y-direction zero-position deviation and rotation angle zero-position deviation as target X-direction zero-position deviation, target Y-direction zero-position deviation and target rotation angle zero-position deviation.
In the application, the loss function is calculated based on the iteration of the steps (B) to (E) until the loss value is smaller than the preset loss threshold value, and the zero offset in the X direction, the zero offset in the Y direction and the zero offset in the rotation angle can be determined.
In one example, the nominal zero position includes a nominal zero position X coordinate, a nominal zero position Y coordinate and a nominal zero position rotation angle,
the method for calibrating the horizontal zero position of the mask table comprises the following steps of:
and determining the difference between the nominal zero position X coordinate and the zero position deviation in the X direction of the target as an actual zero position X coordinate corresponding to the mask table, determining the difference between the nominal zero position Y coordinate and the zero position deviation in the Y direction of the target as an actual zero position Y coordinate corresponding to the mask table, determining the difference between the nominal zero position rotation angle and the zero position deviation in the target rotation angle as an actual zero position rotation angle corresponding to the mask table, and controlling the mask table to move to the positions indicated by the actual zero position X coordinate, the actual zero position Y coordinate and the actual zero position rotation angle so as to finish the calibration of the horizontal zero position of the mask table.
Specifically, the actual zero X coordinate can be determined by the following formula:
in the formula (3) of the present application,representing the actual zero X coordinate, +.>Representing a nominal zero X coordinate.
The actual zero Y coordinate is determined by the following formula:
in the formula (4) of the present application,representing the actual zero Y coordinate, +.>Representing a nominal zero Y coordinate.
The actual zero Y coordinate is determined by the following formula:
in the formula (5) of the present application,represents the actual zero rotation angle, +.>Representing a nominal zero rotation angle.
Based on the same application conception, the embodiment of the application also provides a calibration device of the horizontal zero position of the mask stage, which corresponds to the calibration method of the horizontal zero position of the mask stage provided by the embodiment, and because the principle of solving the problem by the device in the embodiment of the application is similar to that of the calibration method of the horizontal zero position of the mask stage of the embodiment of the application, the implementation of the device can refer to the implementation of the method, and the repetition is omitted.
Referring to fig. 6, fig. 6 is a schematic structural diagram of a calibration device for horizontal zero position of a mask stage according to an embodiment of the present application. As shown in fig. 6, the apparatus includes:
the projection module 500 is configured to turn on a light source, and light emitted from the light source forms a grating image corresponding to each grating group on a table reference plate via a plurality of grating groups and an objective lens.
A measurement module 510 for controlling the movable stage to move to perform a plurality of measurements, during each measurement: and controlling the movable workbench to perform spiral search, aligning the image alignment mark with a grating image, and recording the alignment position corresponding to the movable workbench.
The loss function construction module 520 is configured to construct a loss function according to a grating group position of a grating group to which the corresponding grating image belongs on the mask stage, a mark position of an image alignment mark on the movable workbench, an alignment position corresponding to the movable workbench obtained by each measurement, and a horizontal zero offset corresponding to the mask stage.
The determining module 530 uses a gradient descent method to iteratively calculate the loss function and determine the target horizontal zero bias corresponding to the mask stage.
The calibration module 540 is configured to complete calibration of the horizontal zero of the mask stage according to the nominal zero of the mask stage and the target horizontal zero offset.
Referring to fig. 7 based on the same application concept, fig. 7 shows a schematic structural diagram of an electronic device provided for an embodiment of the present application, and an electronic device 600 includes: processor 610, memory 620, and bus 630, memory 620 storing machine-readable instructions executable by processor 610, which when executed by processor 610 perform the steps of a method for calibrating mask stage horizontal zero as provided in any of the embodiments described above, when electronic device 600 is in operation, processor 610 and memory 620 are in communication via bus 630.
Based on the same application conception, the embodiment of the application also provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program executes the steps of the calibration method of the horizontal zero position of the mask stage provided by the embodiment when being run by a processor.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described system and apparatus may refer to corresponding procedures in the foregoing method embodiments, which are not described herein again. In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. The above-described apparatus embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and there may be other manners of division in actual implementation, and for example, multiple units 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 through some communication interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on 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 the embodiments 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 functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the 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 program codes.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily appreciate variations or alternatives within the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.
Claims (10)
1. The method for calibrating the horizontal zero position of the mask table is applied to a measuring system, the measuring system comprises a light source, the mask table, an objective lens and a movable workbench, and is characterized in that a mask reference plate is fixed on the mask table, a plurality of grating groups are formed on the mask reference plate, a workbench reference plate is fixed on the movable workbench, an image alignment mark is formed on the workbench reference plate,
wherein the method comprises the following steps:
turning on a light source, wherein light emitted by the light source passes through the plurality of grating groups and the objective lens, and a grating image corresponding to each grating group is formed on the workbench reference plate;
controlling the movable stage to move to perform a plurality of measurements, during each measurement: controlling the movable workbench to perform spiral search, enabling the image alignment mark to be aligned with a grating image, and recording an alignment position corresponding to the movable workbench;
constructing a loss function according to the grating group position of the grating group to which the grating image corresponding to each measurement belongs on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench obtained by each measurement and the horizontal zero offset corresponding to the mask table;
iteratively calculating the loss function by using a gradient descent method, and determining a target horizontal zero offset corresponding to the mask table;
and according to the nominal zero position of the mask table and the target horizontal zero position deviation, the calibration of the horizontal zero position of the mask table is completed.
2. The method of claim 1, wherein each grating set comprises an X-direction grating and a Y-direction grating, the image alignment marks comprise an X-direction alignment mark and a Y-direction alignment mark, the grating images comprise an X-direction grating image and a Y-direction grating image, the alignment positions comprise X-alignment coordinates and Y-alignment coordinates corresponding to the movable stage,
wherein the alignment position of the movable table corresponding to each measurement procedure is determined by:
during this measurement, the following process is performed:
the movable workbench is controlled to perform spiral search according to a preset unit step length, and the X-direction grating overlapping rate between the X-direction grating image fed back by the X-direction alignment mark and the Y-direction grating overlapping rate between the Y-direction grating image fed back by the Y-direction alignment mark and the Y-direction alignment mark are respectively obtained when one preset unit step length is moved;
and determining an X alignment coordinate and a Y alignment coordinate corresponding to the measurement according to the X-direction grating overlapping rate and the Y-direction grating overlapping rate corresponding to each movement of the movable workbench.
3. The method of claim 2, wherein the X-alignment coordinates and Y-alignment coordinates corresponding to the movable stage during each measurement are determined by:
during this measurement:
determining an X coordinate of the movable workbench corresponding to the maximum X-direction grating overlapping rate as an X alignment coordinate;
and determining the Y coordinate of the movable workbench corresponding to the maximum Y-direction grating overlapping rate as Y alignment coordinate.
4. The method of claim 2, wherein the grating set positions comprise an X-coordinate of an X-direction grating on the mask stage and a Y-coordinate of a Y-direction grating on the mask stage, the horizontal nulls comprise an X-direction null, a Y-direction null and a rotation angle null of a nominal null relative to an actual null of the mask stage, the mark positions comprise an X-coordinate of an X-direction alignment mark on the movable stage and a Y-coordinate of a Y-direction alignment mark on the movable stage,
wherein the loss function is constructed by the following formula:
in this formula, F (-) represents the loss function, n represents the total number of measurements, rz 0 For zero deviation of rotation angle, x pi Representing the X coordinate, y of the X-direction grating corresponding to the ith measurement on the mask stage pi Representing the Y coordinate of the Y-direction grating corresponding to the ith measurement on the mask stage;
x 0 is zero offset in X direction, y 0 Is zero offset in Y direction, x g Representing the X coordinate, y of the X direction alignment mark on the movable workbench g Representing the Y coordinate, x of the Y-direction alignment mark on the movable worktable si Representing the X alignment coordinate, y corresponding to the ith measurement si Indicating the Y-alignment coordinate corresponding to the ith measurement.
5. The method of claim 4, wherein iteratively calculating the loss function using a gradient descent method, the step of determining a target horizontal zero bias for the mask stage comprises:
(A) Determining a first partial guide expression of the loss function on the zero offset in the X direction, a second partial guide expression of the zero offset in the Y direction and a third partial guide expression of the zero offset in the rotation angle respectively;
(B) Substituting the current X-direction zero offset, the current Y-direction zero offset and the current rotation angle zero offset into a first partial guide expression, a second partial guide expression and a third partial guide expression respectively to obtain an X partial guide value corresponding to the first partial guide expression, a Y partial guide value corresponding to the second partial guide expression and a rotation angle partial guide value corresponding to the third partial guide expression;
(C) Respectively updating the zero offset in the X direction, the zero offset in the Y direction and the zero offset in the rotation angle according to the calculated X partial guide value, the Y partial guide value and the rotation angle partial guide value;
(D) Substituting the updated zero offset in the X direction, the updated zero offset in the Y direction and the updated zero offset in the rotation angle into the loss function, and calculating to obtain a loss value;
(E) And comparing the loss value with a preset loss threshold value, and determining the target horizontal zero offset according to a comparison result.
6. The method of claim 5, wherein step (C) comprises:
calculating a first product between the X-direction deviation value and the unit step length of the mask stage, and determining the sum value between the first product and the current X-direction zero offset as updated X-direction zero offset;
calculating a second product between the Y-direction deviation value and the unit step length of the mask table, and determining the sum value between the second product and the current Y-direction zero offset as updated Y-direction zero offset;
and calculating a third product between the rotation angle deviation value and the unit step length of the mask table, and determining the sum value between the third product and the zero offset of the current rotation angle as the updated zero offset of the rotation angle.
7. The method of claim 6, wherein the target horizontal zero comprises a target X-direction zero, a target Y-direction zero, and a target rotational angle zero,
wherein step (E) comprises:
if the loss value is greater than or equal to the preset loss threshold value, returning to the step (B) by using the updated X deviation, Y deviation and rotation angle deviation;
and if the loss value is smaller than the preset loss threshold value, respectively determining the updated X-direction zero offset, Y-direction zero offset and rotation angle zero offset as target X-direction zero offset, target Y-direction zero offset and target rotation angle zero offset.
8. The method of claim 7 wherein the nominal zero position comprises a nominal zero position X coordinate, a nominal zero position Y coordinate, and a nominal zero position rotation angle,
the step of completing the calibration of the horizontal zero position of the mask table according to the nominal zero position of the mask table and the target horizontal zero position deviation comprises the following steps:
determining the difference value between the nominal zero position X coordinate and the zero position deviation of the target X direction as an actual zero position X coordinate corresponding to the mask table;
determining the difference value between the nominal zero Y coordinate and the zero deviation of the target Y direction as an actual zero Y coordinate corresponding to the mask table;
determining the difference value between the nominal zero rotation angle and the zero deviation of the target rotation angle as an actual zero rotation angle corresponding to the mask table;
and controlling the mask table to move to the positions indicated by the actual zero X coordinate, the actual zero Y coordinate and the actual zero rotation angle so as to finish the calibration of the horizontal zero of the mask table.
9. The calibration device for the horizontal zero position of the mask table is applied to a measurement system, the measurement system comprises a light source, the mask table, an objective lens and a movable workbench, and is characterized in that a mask reference plate is fixed on the mask table, a plurality of grating groups are formed on the mask reference plate, a workbench reference plate is fixed on the movable workbench, an image alignment mark is formed on the workbench reference plate,
the device comprises:
the projection module is used for starting a light source, and light emitted by the light source forms a grating image corresponding to each grating group on the workbench reference plate through the grating groups and the objective lens;
a measurement module for controlling the movable table to move to perform a plurality of measurements, during each measurement: controlling the movable workbench to perform spiral search, aligning the image alignment mark with a grating image, and recording an alignment position corresponding to the movable workbench;
the loss function construction module is used for constructing a loss function according to the grating group position of the grating group on the mask table, the mark position of the image alignment mark on the movable workbench, the alignment position corresponding to the movable workbench and the horizontal zero offset corresponding to the mask table, which are obtained by each measurement, of the grating group to which the corresponding grating image belongs;
the determining module is used for iteratively calculating the loss function by using a gradient descent method and determining the target horizontal zero offset corresponding to the mask table;
and the calibration module is used for completing the calibration of the horizontal zero position of the mask table according to the nominal zero position of the mask table and the target horizontal zero position deviation.
10. An electronic device, comprising: a processor, a memory and a bus, said memory storing machine readable instructions executable by said processor, said processor and said memory communicating via said bus when the electronic device is running, said machine readable instructions being executed by said processor to perform the steps of the method of calibrating horizontal zero of a mask table according to any of claims 1 to 8.
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| CN202311146239.5A CN117168320A (en) | 2023-09-06 | 2023-09-06 | Calibration method and device for horizontal zero position of mask table and electronic equipment |
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| CN202311146239.5A CN117168320A (en) | 2023-09-06 | 2023-09-06 | Calibration method and device for horizontal zero position of mask table and electronic equipment |
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