CN112904683A - Horizontal calibration method and device of projection lithography equipment - Google Patents

Abstract

The invention discloses a horizontal calibration method and a horizontal calibration device of projection lithography equipment, wherein the method comprises the steps of firstly, aligning a positioning mark area on a calibration plate by using an alignment sensor in the projection lithography equipment, and adjusting the measurement attitude of a workpiece table; then controlling the workpiece table to carry the calibration plate to move along the first direction; then, acquiring the coordinate of the central position of the workpiece table in real time by using a position sensor; then the focusing and leveling sensor projects light spots to the calibration plate, and the light intensity of the light spots reflected by the second reflection area is obtained in real time; then, acquiring coordinates of the central position of the second reflection area of the corresponding calibration plate under a workpiece table coordinate system; and then, acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate, thereby realizing the horizontal calibration of the projection lithography equipment and enabling the mask pattern of a mask table in the projection lithography equipment to be accurately copied onto the surface of a substrate.

Description

Horizontal calibration method and device of projection lithography equipment

Technical Field

The embodiment of the invention relates to the technical field of optical measurement, in particular to a horizontal calibration method and a horizontal calibration device for projection lithography equipment.

Background

Projection lithography machines for optical lithography are well known in integrated circuit manufacturing facilities. In a projection lithography machine, an exposure beam illuminates a mask, on which an integrated circuit pattern is inscribed, the mask is imaged on a substrate via a projection objective, and a photoresist coated on the substrate is exposed, so that the mask pattern is reproduced onto the substrate surface.

However, due to factors such as mounting or mechanical drift, the focus and leveling sensor is horizontally offset with respect to the projection objective and the entire mask, so that the central spot position of the exposure beam is not coincident with the intersection (intersection between the optical axis of the projection objective and the workpiece stage), and the entire mask pattern is horizontally offset on the substrate surface, thereby causing a failure of the substrate mask.

Disclosure of Invention

The invention provides a horizontal calibration method and a horizontal calibration device of a projection lithography device, which are used for realizing the horizontal calibration of the projection lithography device, so that a mask pattern of a mask table in the projection lithography device can be accurately copied onto a substrate surface.

To achieve the above object, a first embodiment of the present invention provides a horizontal calibration method for a projection lithography apparatus, the projection lithography apparatus including a calibration plate, the calibration plate including a positioning mark region, a first reflection region and at least one second reflection region, the calibration plate being located on a workpiece stage of the projection lithography apparatus; the horizontal calibration method of the projection photoetching equipment comprises the following steps:

aligning a positioning mark area on the calibration plate by using an alignment sensor in the projection lithography equipment, and adjusting the measurement attitude of the workpiece table to make one side of the calibration plate parallel to a first direction and the other side of the calibration plate parallel to a second direction, wherein the first direction is perpendicular to the second direction;

controlling the workpiece table to carry the calibration plate to move along a first direction;

acquiring the coordinate of the center position of the workpiece table in real time by using a position sensor in the projection photoetching equipment, and recording the coordinate as a first coordinate;

projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, and acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity; the first light intensity corresponds to the first coordinate one by one;

acquiring the coordinate of the position of the central position of the second reflection area of the calibration plate under the workpiece table coordinate system, and recording the coordinate as a second coordinate;

and acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate. According to an embodiment of the present invention, obtaining the measured position of the light spot according to the relationship between the first light intensity and the first coordinate and the second coordinate comprises:

and acquiring the central position coordinates of the second reflection area when the central position of the light spot is overlapped with the central position of the second reflection area as the actually measured position of the light spot.

According to an embodiment of the present invention, acquiring coordinates of the center position of the second reflection area when the center position of the light spot coincides with the center position of the second reflection area as the measured position of the light spot includes:

establishing a coordinate system by taking the first light intensity as a longitudinal axis and the first coordinate as a transverse axis, and obtaining an axisymmetric pattern, wherein the transverse axis coordinate at the intersection point of the axis of the axisymmetric pattern and the transverse axis is the coordinate of the central position of the workpiece table when the central position of the light spot is superposed with the central position of the second reflection area;

and acquiring the central position coordinate of the second reflection area as the actually measured position of the light spot according to the central position coordinate of the workpiece table.

According to one embodiment of the invention, after the calibration plate is aligned, an included angle between one side of the workpiece table and the first direction is theta;

acquiring a first coordinate representation P (X, Y) with a field coordinate system of a projection objective in the projection lithography equipment as a first coordinate system;

establishing a rectangular coordinate system by taking the center of the workpiece table as an origin, one side of the workpiece table as a transverse axis and the other side of the workpiece table as a longitudinal axis to obtain a second coordinate system, wherein the second coordinate system represents R (U, V);

acquiring a measured position table of the light spot according to the first coordinate representation P (X, Y) and the second coordinate representation R (U, V)Shows the general formula of S (X, Y),

according to one embodiment of the invention, the θ is zero degrees.

According to one embodiment of the invention, the second reflective area of the calibration plate is a chrome reflective area, the first reflective area is a quartz transparent area, and the reflectivity of the second reflective area is greater than the reflectivity of the first reflective area.

According to one embodiment of the invention, the calibration plate comprises a plurality of identical second reflection areas, and the plurality of second reflection areas are identical to the light spot layout projected by the focusing and leveling sensor to the calibration plate.

According to one embodiment of the present invention, the calibration plate includes a plurality of different second reflection regions, widths of the plurality of second reflection regions sequentially increase in a first direction, and widths of the plurality of second reflection regions sequentially increase in a second direction.

According to one embodiment of the invention, the workpiece stage comprises a first area for carrying a substrate and a second area which is a four-corner area except the first area, and the calibration plate is located at one corner of the second area of the workpiece stage.

To achieve the above object, an embodiment of a second aspect of the present invention provides a horizontal calibration apparatus for a projection lithographic apparatus,

the calibration plate comprises a positioning mark area, a first reflection area and at least one second reflection area, and is positioned on a workpiece table of the projection lithography equipment;

the adjusting module is used for aligning a positioning mark area on the calibration plate by using an alignment sensor in the projection lithography equipment, and adjusting the measurement attitude of the workpiece table to enable one side of the calibration plate to be parallel to a first direction and the other side of the calibration plate to be parallel to a second direction, wherein the first direction is perpendicular to the second direction;

the motion module is used for controlling the workpiece table to carry the calibration plate to move along a first direction;

the first coordinate acquisition module is used for acquiring the coordinate of the central position of the workpiece table in real time by using a position sensor in the projection photoetching equipment and recording the coordinate as a first coordinate;

the first light intensity acquisition module is used for projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity; wherein the first light intensity and the first coordinate form a one-to-one correspondence;

the second coordinate acquisition module is used for acquiring the corresponding coordinate of a second reflection area of the calibration plate and recording the coordinate as a second coordinate;

and the actual measurement position acquisition module is used for acquiring the actual measurement position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate.

According to the horizontal calibration method and device of the projection lithography equipment provided by the embodiment of the invention, the projection lithography equipment comprises a calibration plate, the calibration plate comprises a positioning mark area, a first reflection area and at least one second reflection area, and the calibration plate is positioned on a workpiece table of the projection lithography equipment; the horizontal calibration method of the projection photoetching equipment comprises the following steps:

firstly, aligning a positioning mark area on a calibration plate by using an alignment sensor in projection lithography equipment, and adjusting the measurement attitude of a workpiece table to enable one side of the calibration plate to be parallel to a first direction and the other side of the calibration plate to be parallel to a second direction, wherein the first direction is vertical to the second direction; then controlling the workpiece table to carry the calibration plate to move along the first direction; then, acquiring the coordinate of the center position of the workpiece table in real time by using a position sensor in the projection photoetching equipment, and recording the coordinate as a first coordinate; then, projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, and acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity; then, position coordinates of the central position of a second reflection area of the calibration plate under a workpiece table coordinate system are obtained and recorded as second coordinates, wherein the first light intensity corresponds to the first coordinates one by one; and then, acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate, thereby realizing the horizontal calibration of the projection lithography equipment, so that a mask pattern of a mask table in the projection lithography equipment can be accurately copied onto the surface of a substrate.

Drawings

FIG. 1 is a schematic diagram of a prior art projection lithographic apparatus;

FIG. 2 is a schematic diagram of a spot projection position based on the projection lithographic apparatus of FIG. 1;

FIG. 3 is a schematic diagram of a projection lithographic apparatus according to the prior art;

FIG. 4 is a schematic diagram of a spot projection position based on the projection lithographic apparatus of FIG. 3;

FIG. 5 is a schematic diagram of a projection lithographic apparatus according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a calibration plate in a projection lithographic apparatus according to an embodiment of the present invention;

FIG. 7 is a flow chart of a method of horizontal calibration of a projection lithographic apparatus according to an embodiment of the invention;

FIG. 8 is a graph of a first intensity versus a second coordinate for a projection lithographic apparatus according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a process of moving a workpiece table in a first direction in a projection lithographic apparatus according to an embodiment of the invention;

FIG. 10 is a schematic diagram of a process of moving a workpiece table in a first direction in a projection lithographic apparatus according to another embodiment of the present invention;

FIG. 11 is a graph of a first intensity versus a second coordinate for the projection lithographic apparatus according to the embodiment of FIG. 10;

FIG. 12 is a schematic diagram of a process of moving a workpiece table in a first direction in a projection lithographic apparatus according to yet another embodiment of the invention;

FIG. 13 is a graph of a first intensity versus a second coordinate for the projection lithographic apparatus according to the embodiment of FIG. 12;

FIG. 14 is a schematic diagram of a structure in which a calibration plate is mounted on a stage in a projection lithographic apparatus according to an embodiment of the present invention;

FIG. 15 is a schematic view of a process of moving a workpiece table in a first direction in a projection lithographic apparatus according to still another embodiment of the invention;

FIG. 16 is a schematic diagram illustrating a process of moving a workpiece stage in a first direction in a projection lithographic apparatus according to still another embodiment of the invention;

FIG. 17 is a schematic diagram of a calibration plate in a projection lithographic apparatus according to an embodiment of the invention;

FIG. 18 is a schematic diagram of a calibration plate in a projection lithographic apparatus according to another embodiment of the present invention;

FIG. 19 is a block diagram of a horizontal calibration apparatus of a projection lithographic apparatus according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

FIG. 1 is a schematic diagram of a prior art projection lithographic apparatus. As shown in FIG. 1, the projection lithographic apparatus comprises: the mask stage 1, the mask 2, the projection objective 3, the light spot projection branch 41 of the focusing and leveling sensor 4, the light spot detection branch 42 of the focusing and leveling sensor 4, the workpiece stage 5, the alignment sensor 9 and the position sensor 10, wherein the workpiece stage 5 is used for bearing the substrate 6.

Projection lithographic apparatus measures and exposes a substrate 6 coated with photoresist, requiring the upper surface of the substrate 6 to be controlled within the available depth of focus of the projection objective 3. The focusing and leveling sensor 4 is used for measuring the height and the inclination of the upper surface of the substrate 6, can be used as a position closed-loop sensor of a vertical movement axis of the workpiece table 5, and is matched with an actuator for vertical movement of the workpiece table 5 to complete the control target. The measurements of a vertical measurement system are typically associated with the definition of a horizontal position. The focusing and leveling sensor 4 of the mainstream lithography machine adopts a photoelectric multi-light-spot scheme, light spots 8 are emitted from the projection branch 41 to the substrate 6 below the optical axis of the objective lens, the distribution of the light spots 8 is formed on the substrate 6 (as shown in fig. 2), the light spots 8 can independently measure height data, and the total height and inclination of the coverage area of the light spots 8 can be obtained by combining the measurement result of the light spots 8 and the horizontal position of the light spots 8.

However, due to factors such as installation accuracy or mechanical drift, the horizontal position of the light spot of the focusing and leveling sensor 4 may not coincide with the zero position of the horizontal movement axis of the workpiece stage 5 (as shown in fig. 3), where the zero position of the horizontal movement axis of the workpiece stage 5 is described with the optical axis of the objective lens as a reference, so that the height and inclination measurement data of the focusing and leveling sensor 4 and the vertical axis position sensor of the workpiece stage 5 are inconsistent, and the vertical control performance of the system is affected (wherein the distribution of the moved light spots 8 is shown in fig. 4).

According to an embodiment of the invention, as shown in fig. 5 and 6, the projection lithography apparatus in this embodiment comprises a calibration plate 7, the calibration plate 7 comprises a positioning mark region 71, a first reflection region 72 and at least one second reflection region 73, and the calibration plate 7 is located on a workpiece stage 5 of the projection lithography apparatus. FIG. 7 is a flowchart of a method for horizontal calibration of a projection lithographic apparatus according to an embodiment of the present invention. As shown in fig. 7, the method for horizontal calibration of a projection lithographic apparatus comprises the steps of:

s101, aligning a positioning mark area on a calibration plate 7 by using an alignment sensor in projection lithography equipment, and adjusting the measurement attitude of a workpiece table 5 to enable one side of the calibration plate 7 to be parallel to a first direction and the other side to be parallel to a second direction, wherein the first direction is vertical to the second direction;

the positioning mark areas 71 of the calibration plate 7 are located at four corners of the calibration plate 7, the positioning marks may be cross-shaped marks, and the mode of mounting the calibration plate 7 on the workpiece table 5 may be fixed by screws or fixed by dispensing.

After the alignment plate 7 is mounted, the alignment sensor 9 of the projection lithographic apparatus is used to align the alignment mark area 71 on the alignment plate 7, and align the alignment mark area with the cross-shaped cursor of the alignment sensor 9, so that one side of the alignment plate 7 is parallel to the horizontal side of the alignment cross-shaped mark, and the other side of the alignment plate 7 is parallel to the vertical side of the alignment cross-shaped mark, according to the first direction marked in fig. 5, the second direction can be inward or outward perpendicular to the paper surface, and the first direction and the second direction form a plane, and then the alignment plate 7 is adjusted by rotating the workpiece stage 5 in the plane. It should be noted that the first direction and the second direction may be interchanged, and are not limited herein.

S102, controlling the workpiece table 5 to carry the calibration plate 7 to move along a first direction;

s103, acquiring the coordinate of the central position of the workpiece table 5 in real time by using the position sensor 10, and recording the coordinate as a first coordinate;

it is understood that the first coordinates are coordinates in the coordinate system of the projection objective 2.

S104, projecting light spots 8 to the calibration plate 7 by using the focusing and leveling sensor 4 in the projection lithography equipment, and acquiring light intensity of the light spots 8 reflected by the second reflection area 73 of the calibration plate 7 in real time and recording the light intensity as first light intensity, wherein the first light intensity corresponds to the first coordinates one by one;

s105, acquiring position coordinates of the central position of the second reflection area 73 of the calibration plate 7 in a workpiece table coordinate system, and recording the position coordinates as second coordinates;

since the positions of the second reflection region 73 and the stage 5 on the calibration plate 7 are relatively fixed, the coordinates of the second reflection region 73 in the coordinate system of the stage 5 can be acquired, and preferably, the position of the second reflection region 73 and the position of the stage 5 can be aligned by the alignment sensor 9, and the relative position of the second reflection region 73 and the stage 5 can be acquired.

It is understood that the second reflective region 73 is a square, and the coordinates of the center position of the black square under the stage coordinate system can be obtained by taking the orientation of fig. 6 as an example.

And S106, acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate.

According to an embodiment of the present invention, acquiring the measured position of the light spot according to the relationship between the first light intensity and the first coordinate and the second coordinate comprises:

and acquiring the central position coordinates of the second reflection area when the central position of the light spot is coincident with the central position of the second reflection area as the actual measurement position of the light spot.

According to an embodiment of the present invention, acquiring coordinates of a center position of the second reflection area when the center position of the light spot coincides with the center position of the second reflection area as the measured position of the light spot includes:

establishing a coordinate system by taking the first light intensity as a longitudinal axis and the first coordinate as a transverse axis, and obtaining an axisymmetric pattern, wherein the transverse axis coordinate at the intersection point of the axis of the axisymmetric pattern and the transverse axis is the coordinate of the central position of the workpiece table when the central position of the light spot is superposed with the central position of the second reflection area;

and acquiring the central position coordinates of the second reflection area as the actual measurement position of the light spot according to the coordinates of the central position of the workpiece table.

It should be noted that the axisymmetric pattern may be a trapezoid or a triangle, where the axisymmetric pattern is a trapezoid (as shown in fig. 8 and 13) when the width of the light spot in the first direction is smaller or larger than the width of the second reflective region, and the axisymmetric pattern is a triangle (as shown in fig. 11) when the width of the light spot in the first direction is equal to the width of the second reflective region.

It should be noted that, as shown in fig. 9, the width of the second reflection region 73 of the calibration plate 7 along the first direction is smaller than the width of the light spot along the first direction, so that the workpiece stage 5 carries the calibration plate 7 to move along the first direction, the light spot 8 starts to hit the second reflection region 73 by a small amount, and the light intensity of the light spot 8 reflected by the second reflection region 73 gradually increases; as the calibration plate 7 continues to move in the first direction, the light spot 8 partially impinges on the second reflection area 73, and the light intensity of the light spot 8 reflected by the second reflection area 73 increases to the maximum; as the calibration plate 7 continues to move in the first direction, the intensity of the light spot 8 reflected by the second reflective region 73 increases to a maximum for a period of time; until the area of the spot 8 hitting the second reflection region 73 is gradually reduced, the intensity of the spot 8 reflected by the second reflection region 73 is gradually reduced. Therefore, a coordinate system is established with the first light intensity as a vertical coordinate and the first coordinate as a horizontal coordinate to form a trapezoidal image (as shown in fig. 8), which includes a first-stage ascending image, a second-stage flat image and a third-stage descending image, wherein the first coordinate may be a coordinate of the center position of the workpiece stage 5.

It should be noted that, as shown in fig. 10, when the width of the second reflection region 73 of the calibration plate 7 in the first direction is equal to the width of the light spot 8 in the first direction, then when the workpiece stage 5 carries the calibration plate 7 to move in the first direction, the light spot 8 is projected onto the second reflection region 73 of the calibration plate 7, as the workpiece stage 5 moves in the first direction, the area of the light spot 8 projected onto the second reflection region 73 of the calibration plate 7 increases, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes stronger, until the light spot 8 is entirely projected onto the second reflection region 73 of the calibration plate 7, and at this time, the light intensity of the light spot 8 reflected by the second reflection region 73 of the calibration plate 7 is strongest; subsequently, the workpiece stage 5 continues to move along the first direction, the light spot 8 moves out of the second reflection region 73, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes smaller and smaller until the whole light spot 8 moves out of the second reflection region 73, and the light intensity of the light spot 8 reflected by the second reflection region 73 at this time is zero. It can be understood that a coordinate system is established with the first light intensity as the ordinate and the first coordinate as the abscissa, and an image formed by the first light intensity and the second coordinate is a broken-line image (as shown in fig. 11), that is, only the first-stage rising image and the third-stage falling image are included.

As shown in fig. 12, when the width of the second reflection region 73 of the calibration plate 7 in the first direction is greater than the width of the light spot 8 in the first direction, then when the workpiece stage 5 moves along the first direction with the calibration plate 7, the light spot 8 projects onto the second reflection region 73 of the calibration plate 7, as the workpiece stage 5 moves along the first direction, the area of the light spot 8 projecting onto the second reflection region 73 of the calibration plate 7 increases, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes stronger, until the light spot 8 is entirely projected onto the second reflection region 73 of the calibration plate 7, and at this time, the light intensity of the light spot 8 reflected by the second reflection region 73 of the calibration plate 7 is strongest; subsequently, the workpiece stage 5 continues to move in the first direction, the light spot 8 continues to be projected on the second reflection region 73 as a whole for a period of time, and then the light spot 8 moves out of the second reflection region 73, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes smaller and smaller until the whole light spot 8 moves out of the second reflection region 73, and the light intensity of the light spot 8 reflected by the second reflection region 73 is zero at this time. It is understood that the first intensity is an ordinate, the first coordinate is an abscissa to establish a coordinate system, and an image formed by the first intensity and the second coordinate is a trapezoidal image (as shown in fig. 13).

The coordinates of the central position of the second reflection area when the central position of the light spot is overlapped with the central position of the second reflection area are used as the actual measurement position of the light spot, and further the coordinates of the central position of the workpiece table when the central position of the light spot is overlapped with the central position of the second reflection area can be used as the coordinates of the central position of the workpiece table when the central position of the light spot is overlapped with the central position of the second reflection area through the horizontal coordinates of the intersection point of the symmetric axis and the horizontal axis of the axisymmetric pattern in fig. 8; and then the coordinates of the central position of the second reflection area are obtained through the coordinates of the central position of the workpiece table, so that the central position of the light spot is obtained, namely the actually measured position of the light spot is obtained

According to an embodiment of the present invention, as shown in fig. 14, after the calibration plate 7 is aligned, the angle between one side of the workpiece stage 5 and the first direction is θ;

taking a field coordinate system of a projection objective in the projection lithography equipment as a first coordinate system, and expressing the first coordinate as P (X, Y) under the first coordinate system;

establishing a rectangular coordinate system as a second coordinate system by taking the center of the workpiece table as an origin, one side of the workpiece table as a transverse axis and the other side of the workpiece table as a longitudinal axis, and acquiring a second coordinate representation R (U, V);

from the first coordinate representation P (X, Y) and the second coordinate representation R (U, V), a measured position representation S (X, Y) of the spot is obtained, and when the center position of the spot and the center position of the second reflection area 73 coincide,

thereby obtaining the measured position of the spot by the vector representation. In the formula, θ is a rotation adjustment posture of the workpiece stage, and it can be understood that when the calibration plate 7 and the workpiece stage 5 are mounted without errors, one side of the calibration plate 7 is parallel to one side of the workpiece stage 5, and the other side of the calibration plate 7 is parallel to the other side of the workpiece stage 5, then θ is zero, and the position coordinate of the center of the second reflection region of the calibration plate 7 in the workpiece stage coordinate system is not deflected. When calibrating the boardWhen the mounting error of the calibration plate 7 and the workpiece table 5 occurs, as shown in fig. 14, an included angle θ between one side of the calibration plate 7 and one side of the workpiece table is not zero, and at this time, the position coordinate of the center of the second reflection region of the calibration plate 7 in the workpiece table coordinate system is deviated to

According to an embodiment of the present invention, as shown in fig. 15 and 16, the stage 5 includes a first region 51 and a second region 52, the first region 51 is used for carrying the substrate 6, the second region 52 is a four-corner region except the first region 51, and the calibration plate 7 is located at one corner in the second region 52 of the stage 5.

As shown in fig. 11, the calibration plate 7 is located at one corner of the second area 52 of the workpiece stage, and the calibration plate 7 may be fixed by a screw fixing method, or the calibration plate 7 may be fixed by a glue dispensing method, which is not limited in this embodiment.

It should be noted that, in the coordinate system xy established in fig. 15 and fig. 16, the workpiece stage 5 carries the calibration plate 7 to move along the first direction as the projection objective coordinate system, and as shown in fig. 16, when the central position of the second reflection region 73 of the calibration plate 7 coincides with the central position of the spot 8, the actual measurement position of the spot can be obtained.

It should be noted that the above embodiment is to solve the case where the offset occurs in the first direction. The solution is equally applicable to solve the situation where an offset occurs in the second direction. If the light spot has a deviation in both the first direction and the second direction, the deviation of the light spot in the first direction and the deviation of the light spot in the second direction may be obtained in a gradual approximation manner, which is not limited in this embodiment.

According to one embodiment of the invention, the second reflective area 73 of the calibration plate 7 is a chrome reflective area and the first reflective area 72 is a quartz transparent area. Wherein the reflectivity of the second reflective region 73 is greater than the reflectivity of the first reflective region 72.

The first reflective region 72, i.e. the quartz transparent region, hardly reflects light spots, the second reflective region 73 is a chromium reflective region, chromium may be coated on the quartz plate to form the second reflective region 73, and the second reflective region 73 is a high reflective region.

According to one embodiment of the present invention, the calibration plate 7 includes a plurality of identical second reflection areas 73, and the plurality of second reflection areas 73 are arranged in the same manner as the light spots 8 projected onto the calibration plate 7 by the focus and leveling sensor 4.

As shown in fig. 17, when the light spots 8 are five light spots, the calibration plate 7 may include five identical second reflection regions 73, and the five second reflection regions 73 have the same layout as the five light spots 8, so that the offsets of the five light spots 8 can be measured simultaneously, and the measurement efficiency is greatly improved with respect to the case where only one second reflection region 73 is provided in the calibration plate 7 and five second reflection regions 73 are provided at the same time.

According to an embodiment of the present invention, the calibration plate 7 includes a plurality of different second reflection regions 73, and widths of the plurality of second reflection regions 73 sequentially increase in the first direction and widths of the plurality of second reflection regions 73 sequentially increase in the second direction.

As shown in fig. 18, the calibration plate 7 includes a plurality of different second reflection regions 73, and the widths of the plurality of second reflection regions 73 sequentially increase in the first direction, and the widths of the plurality of second reflection regions 73 sequentially increase in the second direction. This allows measuring the displacement of one spot 8 in the first direction or in the second direction a plurality of times. In fig. 18, for example, the width of the first second reflection region 73 in the first row along the first direction may be smaller than the width of the light spot 8 along the first direction, the width of the second reflection region 73 may be equal to the width of the light spot 8 along the first direction, and the width of the third second reflection region 73 may be larger than the width of the light spot 8 along the first direction. The width of the first second reflective region 73 of the second row along the first direction may be smaller than the width of the spot 8 along the first direction, the width of the second reflective region 73 may be equal to the width of the spot 8 along the first direction, and the width of the third second reflective region 73 may be larger than the width of the spot 8 along the first direction. Likewise, the width of the first second reflective region 73 of the third row in the first direction may be smaller than the width of the spot 8 in the first direction, the width of the second reflective region 73 may be equal to the width of the spot 8 in the first direction, and the width of the third second reflective region 73 may be larger than the width of the spot 8 in the first direction.

The width of the first second reflective region 73 of the first column along the second direction may be smaller than the width of the light spot 8 along the second direction, the width of the second reflective region 73 may be equal to the width of the light spot 8 along the second direction, and the width of the third second reflective region 73 may be larger than the width of the light spot 8 along the second direction. The width of the first second reflective region 73 of the second column in the second direction may be smaller than the width of the light spot 8 in the second direction, the width of the second reflective region 73 may be equal to the width of the light spot 8 in the second direction, and the width of the third second reflective region 73 may be larger than the width of the light spot 8 in the second direction. The width of the first second reflective area 73 of the third column in the second direction may be smaller than the width of the light spot 8 in the second direction, the width of the second reflective area 73 may be equal to the width of the light spot 8 in the second direction, and the width of the third second reflective area 73 may be larger than the width of the light spot 8 in the second direction. Thus, the displacement of one spot 8 in the first direction or in the second direction under the second reflection areas 73 with different widths can be measured simultaneously, and the measured positions of the spots 8 under the second reflection areas 73 with different widths can be averaged finally. Therefore, the detection efficiency is improved, and the detection precision is increased.

FIG. 19 is a block diagram of a horizontal calibration apparatus of a projection lithographic apparatus according to an embodiment of the present invention. As shown in fig. 1 and 19, comprising a calibration plate 7, the calibration plate 7 comprising a positioning mark region 71, a first reflective region 72 and at least one second reflective region 73, the calibration plate 7 being positioned on a workpiece stage 5 of a projection lithographic apparatus;

an adjusting module 101, which aligns the alignment mark area 71 on the calibration plate 7 by using an alignment sensor in the projection lithography apparatus, and adjusts the measurement attitude of the workpiece stage 5 so that one side of the calibration plate 7 is parallel to a first direction and the other side is parallel to a second direction, wherein the first direction is perpendicular to the second direction;

the positioning mark areas 71 of the calibration plate 7 are located at four corners of the calibration plate 7, the positioning marks may be cross-shaped marks, and the mode of mounting the calibration plate 7 on the workpiece table 5 may be fixed by screws or fixed by dispensing.

After the calibration plate 7 is mounted, the alignment sensor 9 of the projection lithography apparatus is used to align the alignment mark area 71 on the calibration plate 7, and align the alignment mark area with the cross-shaped cursor of the alignment sensor 9, so that one side of the calibration plate 7 is parallel to the horizontal direction of the positioning cross-shaped mark, and the other side of the calibration plate 7 is parallel to the vertical direction of the positioning cross-shaped mark, according to the first direction marked in fig. 5, the second direction can be inward or outward perpendicular to the paper surface, and the first direction and the second direction form a plane, thereby aligning the calibration plate 7. It should be noted that the first direction and the second direction may be interchanged, and are not limited herein.

The motion module 102 is used for controlling the workpiece table to carry the calibration plate to move along a first direction;

the first coordinate acquisition module 103 is used for acquiring the coordinate of the central position of the workpiece table in real time by using a position sensor and recording the coordinate as a first coordinate;

the first light intensity obtaining module 104 is configured to project a light spot 8 onto the calibration plate 7 by using the focusing and leveling sensor 4 in the projection lithography apparatus, and obtain the light intensity of the light spot 8 reflected by the second reflection region 73 of the calibration plate 7 in real time, and record the light intensity as a first light intensity; the first light intensity corresponds to the first coordinates one by one;

a second coordinate obtaining module 105, configured to obtain a position coordinate of a central position of the second reflection area 73 of the calibration plate 7 in the workpiece table coordinate system, which is recorded as a second coordinate;

since the positions of the second reflection region 73 and the stage 5 on the calibration plate 7 are fixed relative to each other, the coordinates of the second reflection region 73 in the coordinate system of the stage 5 can be acquired.

It is understood that the second reflective region 73 is a square, and the coordinates of the center position of the black square under the stage coordinate system can be obtained by taking the orientation of fig. 6 as an example.

And the actual measurement position acquisition module 106 acquires the actual measurement position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate.

According to an embodiment of the present invention, acquiring the measured position of the light spot according to the relationship between the first light intensity and the first coordinate and the second coordinate comprises:

and acquiring the central position coordinates of the second reflection area when the central position of the light spot is coincident with the central position of the second reflection area as the actual measurement position of the light spot.

According to an embodiment of the present invention, acquiring coordinates of a center position of the second reflection area when the center position of the light spot coincides with the center position of the second reflection area as the measured position of the light spot includes:

establishing a coordinate system by taking the first light intensity as a longitudinal axis and the first coordinate as a transverse axis, and obtaining an axisymmetric pattern, wherein the transverse axis coordinate at the intersection point of the axis of the axisymmetric pattern and the transverse axis is the coordinate of the central position of the workpiece table when the central position of the light spot is superposed with the central position of the second reflection area;

and acquiring the central position coordinates of the second reflection area as the actual measurement position of the light spot according to the coordinates of the central position of the workpiece table.

It should be noted that the axisymmetric pattern may be a trapezoid or a triangle, where the axisymmetric pattern is a trapezoid (as shown in fig. 8 and 13) when the width of the light spot in the first direction is smaller or larger than the width of the second reflective region, and the axisymmetric pattern is a triangle (as shown in fig. 11) when the width of the light spot in the first direction is equal to the width of the second reflective region.

It should be noted that, as shown in fig. 9, the width of the second reflection region 73 of the calibration plate 7 along the first direction is smaller than the width of the light spot along the first direction, so that the workpiece stage 5 carries the calibration plate 7 to move along the first direction, the light spot 8 starts to hit the second reflection region 73 by a small amount, and the light intensity of the light spot 8 reflected by the second reflection region 73 gradually increases; as the calibration plate 7 continues to move in the first direction, the light spot 8 partially impinges on the second reflection area 73, and the light intensity of the light spot 8 reflected by the second reflection area 73 increases to the maximum; as the calibration plate 7 continues to move in the first direction, the intensity of the light spot 8 reflected by the second reflective region 73 increases to a maximum for a period of time; until the area of the spot 8 hitting the second reflection region 73 is gradually reduced, the intensity of the spot 8 reflected by the second reflection region 73 is gradually reduced. Therefore, a coordinate system is established with the first light intensity as a vertical coordinate and the first coordinate as a horizontal coordinate to form a trapezoidal image (as shown in fig. 8), which includes a first-stage ascending image, a second-stage flat image and a third-stage descending image, wherein the first coordinate may be a coordinate of the center position of the workpiece stage 5.

It should be noted that, as shown in fig. 10, when the width of the second reflection region 73 of the calibration plate 7 in the first direction is equal to the width of the light spot 8 in the first direction, then when the workpiece stage 5 carries the calibration plate 7 to move in the first direction, the light spot 8 is projected onto the second reflection region 73 of the calibration plate 7, as the workpiece stage 5 moves in the first direction, the area of the light spot 8 projected onto the second reflection region 73 of the calibration plate 7 increases, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes stronger, until the light spot 8 is entirely projected onto the second reflection region 73 of the calibration plate 7, and at this time, the light intensity of the light spot 8 reflected by the second reflection region 73 of the calibration plate 7 is strongest; subsequently, the workpiece stage 5 continues to move along the first direction, the light spot 8 moves out of the second reflection region 73, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes smaller and smaller until the whole light spot 8 moves out of the second reflection region 73, and the light intensity of the light spot 8 reflected by the second reflection region 73 at this time is zero. It can be understood that a coordinate system is established with the first light intensity as the ordinate and the first coordinate as the abscissa, and an image formed by the first light intensity and the second coordinate is a broken-line image (as shown in fig. 11), that is, only the first-stage rising image and the third-stage falling image are included.

As shown in fig. 12, when the width of the second reflection region 73 of the calibration plate 7 in the first direction is greater than the width of the light spot 8 in the first direction, then when the workpiece stage 5 moves along the first direction with the calibration plate 7, the light spot 8 projects onto the second reflection region 73 of the calibration plate 7, as the workpiece stage 5 moves along the first direction, the area of the light spot 8 projecting onto the second reflection region 73 of the calibration plate 7 increases, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes stronger, until the light spot 8 is entirely projected onto the second reflection region 73 of the calibration plate 7, and at this time, the light intensity of the light spot 8 reflected by the second reflection region 73 of the calibration plate 7 is strongest; subsequently, the workpiece stage 5 continues to move in the first direction, the light spot 8 continues to be projected on the second reflection region 73 as a whole for a period of time, and then the light spot 8 moves out of the second reflection region 73, the light intensity of the light spot 8 reflected by the second reflection region 73 becomes smaller and smaller until the whole light spot 8 moves out of the second reflection region 73, and the light intensity of the light spot 8 reflected by the second reflection region 73 is zero at this time. It is understood that the first intensity is an ordinate, the first coordinate is an abscissa to establish a coordinate system, and an image formed by the first intensity and the second coordinate is a trapezoidal image (as shown in fig. 13).

The coordinates of the central position of the second reflection area when the central position of the light spot is overlapped with the central position of the second reflection area are used as the actual measurement position of the light spot, and further the coordinates of the central position of the workpiece table when the central position of the light spot is overlapped with the central position of the second reflection area can be used as the coordinates of the central position of the workpiece table when the central position of the light spot is overlapped with the central position of the second reflection area through the horizontal coordinates of the intersection point of the symmetric axis and the horizontal axis of the axisymmetric pattern in fig. 8; and then the coordinates of the central position of the second reflection area are obtained through the coordinates of the central position of the workpiece table, so that the central position of the light spot is obtained, namely the actual measurement position of the light spot is obtained.

According to an embodiment of the present invention, as shown in fig. 14, after the calibration plate 7 is aligned, the angle between one side of the workpiece stage 5 and the first direction is θ;

taking a field coordinate system of a projection objective in the projection lithography equipment as a first coordinate system, and expressing the first coordinate as P (X, Y) under the first coordinate system;

establishing a rectangular coordinate system as a second coordinate system by taking the center of the workpiece table as an origin, one side of the workpiece table as a transverse axis and the other side of the workpiece table as a longitudinal axis, and acquiring a second coordinate representation R (U, V);

acquiring a measured position representation S (X, Y) of the spot based on the first coordinate representation P (X, Y) and the second coordinate representation R (U, V),

thereby obtaining the measured position of the spot by the vector representation. In the formula, θ is the rotation adjustment posture of the workpiece table, and it can be understood that, when there is no error in mounting the calibration plate 7 and the workpiece table 5, one side of the calibration plate 7 is not presentParallel to one side of the workpiece table 5 and the other side of the calibration plate 7 parallel to the other side of the workpiece table 5, so that theta is zero degrees, and the position coordinate of the center of the second reflection area of the calibration plate 7 in the workpiece table coordinate system has no deflection. When the installation of the calibration plate 7 and the workpiece stage 5 is in error, as shown in fig. 14, an included angle θ between one side of the calibration plate 7 and one side of the workpiece stage is not zero, and at this time, the position coordinate of the center of the second reflection region of the calibration plate 7 in the workpiece stage coordinate system is deviated into

According to the horizontal calibration method and device of the projection lithography equipment provided by the embodiment of the invention, the projection lithography equipment comprises a calibration plate, the calibration plate comprises a positioning mark area, a first reflection area and at least one second reflection area, and the calibration plate is positioned on a workpiece table of the projection lithography equipment; the horizontal calibration method of the projection photoetching equipment comprises the following steps:

firstly, aligning a positioning mark area on a calibration plate by using an alignment sensor in projection lithography equipment, and adjusting a workpiece table to enable one side of the calibration plate to be parallel to a first direction and the other side of the calibration plate to be parallel to a second direction, wherein the first direction is vertical to the second direction; then controlling the workpiece table to carry the calibration plate to move along the first direction; then, acquiring the coordinate of the central position of the workpiece table in real time by using a position sensor, and recording the coordinate as a first coordinate; then, projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, and acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity; then, coordinates of the center position of a second reflection area of the corresponding calibration plate under a workpiece table coordinate system are obtained and recorded as second coordinates, wherein the first light intensity corresponds to the first coordinates one by one; and then, acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate, thereby realizing the horizontal calibration of the projection lithography equipment, and enabling the mask pattern of a mask table in the projection lithography equipment to be accurately copied onto the surface of the substrate.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A method of horizontal calibration of a projection lithographic apparatus, comprising a calibration plate comprising a positioning mark region, a first reflective region and at least one second reflective region, the calibration plate being located on a workpiece table of the projection lithographic apparatus; the horizontal calibration method of the projection photoetching equipment comprises the following steps:

aligning a positioning mark area on the calibration plate by using an alignment sensor in the projection lithography equipment, and adjusting the measurement attitude of the workpiece table to make one side of the calibration plate parallel to a first direction and the other side of the calibration plate parallel to a second direction, wherein the first direction is perpendicular to the second direction;

controlling the workpiece table to carry the calibration plate to move along a first direction;

acquiring the coordinate of the center position of the workpiece table in real time by using a position sensor in the projection photoetching equipment, and recording the coordinate as a first coordinate;

projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, and acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity;

the first light intensity and the first coordinate form a one-to-one correspondence relationship;

acquiring position coordinates of the central position of a second reflection area of the calibration plate under a workpiece table coordinate system, and recording the position coordinates as second coordinates;

and acquiring the actually measured position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate.

2. The method of claim 1, wherein obtaining the measured position of the spot in combination with the second coordinate from the relationship between the first intensity and the first coordinate comprises:

and acquiring the central position coordinates of the second reflection area when the central position of the light spot is overlapped with the central position of the second reflection area as the actually measured position of the light spot.

3. The method of claim 2, wherein obtaining the coordinates of the center position of the second reflective area when the center position of the light spot coincides with the center position of the second reflective area as the measured position of the light spot comprises:

establishing a coordinate system by taking the first light intensity as a longitudinal axis and the first coordinate as a transverse axis, and obtaining an axisymmetric pattern, wherein the transverse axis coordinate at the intersection point of the axis of the axisymmetric pattern and the transverse axis is the coordinate of the central position of the workpiece table when the central position of the light spot is superposed with the central position of the second reflection area;

and acquiring the central position coordinate of the second reflection area as the actually measured position of the light spot according to the central position coordinate of the workpiece table.

4. The method of horizontal calibration of a projection lithographic apparatus according to claim 3,

after the calibration plate is aligned, an included angle between one side of the workpiece table and the first direction is theta;

acquiring a first coordinate representation P (X, Y) with a field coordinate system of a projection objective in the projection lithography equipment as a first coordinate system;

establishing a rectangular coordinate system by taking the center of the workpiece table as an origin, one side of the workpiece table as a transverse axis and the other side of the workpiece table as a longitudinal axis to obtain a second coordinate system, wherein the second coordinate system represents R (U, V);

obtaining a measured position representation S (X, Y) of the spot from the first coordinate representation P (X, Y) and the second coordinate representation R (U, V),

5. the method of claim 4, wherein θ is zero degrees.

6. The method of claim 1, wherein the second reflective region of the calibration plate is a chrome reflective region, the first reflective region is a quartz transparent region, and the second reflective region has a reflectivity greater than the first reflective region.

7. The method of claim 6, wherein the calibration plate comprises a plurality of identical second reflective regions, and the plurality of second reflective regions are identical to the layout of the spots projected by the focus and leveling sensor onto the calibration plate.

8. The method of claim 6, wherein the calibration plate comprises a plurality of different second reflective regions, and the widths of the plurality of second reflective regions increase sequentially in a first direction and the widths of the plurality of second reflective regions increase sequentially in a second direction.

9. The method of any one of claims 1 to 8, wherein the stage comprises a first region for carrying a substrate and a second region, the second region being a four corner region except the first region, and the calibration plate is located at one corner of the second region of the stage.

10. A horizontal calibration apparatus of a projection lithography apparatus,

the calibration plate comprises a positioning mark area, a first reflection area and at least one second reflection area, and is positioned on a workpiece table of the projection lithography equipment;

the adjusting module is used for aligning a positioning mark area on the calibration plate by using an alignment sensor in the projection lithography equipment, and adjusting the measurement attitude of the workpiece table to enable one side of the calibration plate to be parallel to a first direction and the other side of the calibration plate to be parallel to a second direction, wherein the first direction is perpendicular to the second direction;

the motion module is used for controlling the workpiece table to carry the calibration plate to move along a first direction;

the first coordinate acquisition module is used for acquiring the coordinate of the central position of the workpiece table in real time by using a position sensor in the projection photoetching equipment and recording the coordinate as a first coordinate;

the first light intensity acquisition module is used for projecting light spots to the calibration plate by using a focusing and leveling sensor in the projection lithography equipment, acquiring the light intensity of the light spots reflected by a second reflection area of the calibration plate in real time and recording the light intensity as first light intensity; wherein the first light intensity and the first coordinate form a one-to-one correspondence;

the second coordinate acquisition module is used for acquiring the position coordinate of the central position of the second reflection area of the calibration plate under the workpiece table coordinate system and recording the position coordinate as a second coordinate;

and the actual measurement position acquisition module is used for acquiring the actual measurement position of the light spot by combining the second coordinate according to the relation between the first light intensity and the first coordinate.

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