CN100587603C - Mask alignment mark and alignment method for lithography apparatus - Google Patents

Abstract

The invention discloses a mask alignment mark and an alignment method. The partial structure of the mask alignment mark is inconsistent with other parts, usually longer, which can improve the capture ability of the mark branch for alignment scan, improve the success rate of rough scan, and improve the contrast of the alignment information generated by the alignment scan. It also improves the signal-to-noise ratio of the information used in the alignment process, thereby increasing the accuracy of the mask alignment. The method of generating moiré fringe information by combining radial coarse and fine scanning and tangential rotation coarse and fine scanning can improve the efficiency of alignment scanning; through two directions perpendicular to each other, the grating in the branch that is approximately perpendicular to the alignment mark used The method of generating moiré fringe information combined with rough and fine scanning in the direction improves the efficiency of alignment scanning.

Description

Mask alignment mark and alignment method for lithography apparatus

technical field

The invention relates to an alignment technology of a lithography device, in particular to a mask alignment mark used for a lithography device and an alignment method using the alignment mark.

Background technique

In industrial devices, due to the need for high precision and high productivity, a large number of high-speed real-time signal sampling, data acquisition, and real-time signal processing systems are distributed. Among them, the real-time signal processing system needs to adopt effective information processing models and methods to meet the requirements of high precision and high efficiency. Devices with this requirement include: integrated circuit manufacturing lithography device, liquid crystal panel lithography device, photomask marking device, MEMS/MOEMS lithography device, advanced packaging lithography device, printed circuit board lithography device, printed circuit board processing device etc.

In the previous above-mentioned devices, in order to realize the alignment of the mask pattern on the alignment mark on the workpiece table reference plate and generate high-precision alignment scan information, it is necessary to have a mask alignment capable of generating high-precision alignment scan information mark.

The existing alignment marks, either have poor capture ability, need to add auxiliary mask alignment marks on the mask, and add more alignment scanning methods to perform step-by-step capture, thereby reducing the alignment efficiency; or The signal contrast of a single alignment mark is not high. Although the virtual digital processing method can improve the signal contrast, it also simultaneously amplifies the noise level and cannot physically improve the signal-to-noise ratio, thus limiting the improvement of alignment repeatability. .

Contents of the invention

The technical problem solved by the present invention is to provide a mask alignment mark that improves the capture ability of alignment scanning and the contrast of alignment information, and uses the provided mask alignment mark to perform mask alignment scanning to achieve improved Methods for mask alignment marker aerial image capture capability, alignment precision, and alignment efficiency.

In order to solve the above technical problems, the present invention provides a mask alignment mark, which is respectively placed on the mask of the mask stage and the reference plate of the workpiece stage to provide optical alignment of the mask, wherein the The mask alignment mark includes first, second and third alignment mark branches, wherein the second alignment mark branch is distributed in the shape of a square transmission hole, and the first and third alignment mark branches are related to the second alignment mark branch Rotate each other by 90°, and the first and third alignment mark branches are respectively composed of first, second and third grating mark structures arranged side by side along the direction perpendicular to the grating, wherein the first and third grating mark structures are exactly the same, Distributed on both sides of the second grating mark structure, the lengths of the first and third grating mark structures are different from the length of the second grating mark structure.

Further, the length of the second grating mark structure is 1.2 to 100 times that of the first and third grating mark structures, or the length of the first and third grating mark structures is 1.2 to 100 times that of the second grating mark structure, And the gratings in the first, second and third grating marking structures are subdivided into three fine gratings. Preferably, the length of the second grating mark structure is 1.5 times, 2 times, 5 times, 10 times, 20 times or 50 times that of the first and the third grating mark structure; or the length of the first and the third grating mark structure It is 1.5 times, 2 times, 5 times, 10 times, 20 times or 50 times of the second grating mark structure.

Further, the duty cycle of all the grating mark structures corresponding to the first and third alignment mark branches in the mask alignment mark on the workpiece table reference plate is the same as that corresponding to all the grating mark structures in the mask alignment mark on the mask The duty cycle of the gratings is not equal, while the duty cycle of the small gratings inside all the grating mark structures of the first and third alignment mark branches in the mask alignment marks on the workpiece table reference plate and the mask is based on the alignment signal Modulation and measurement requirements are defined.

Another solution of the present invention is to provide a method for aligning a lithography apparatus using the above-mentioned mask alignment marks, the lithography apparatus has an alignment system, and the alignment system includes: a radiation generator, a mask Graphic irradiation window and its control panel, mask, mask stage, mask stage position detector, projection system, workpiece stage and its reference plate mark of workpiece stage, workpiece stage position detector and radiation detection sensor; wherein, on the mask It includes an exposure mask pattern and several mask alignment marks; the mask pattern irradiation window and its control plate form a transmission window, which transmits the radiation generated by the radiation generator to the exposure mask pattern and mask alignment marks to form a transmission window. image; the projection system projects the transmission image to form an aerial image, and detects the aerial image with the radiation detection sensor under the mark on the workpiece table reference plate; The information includes any one of radiation amplitude intensity information, radiation energy information, radiation phase information or a combination of phase information and the other two kinds of information; the mask stage position detector and the workpiece stage position detector respectively detect the mask position during the alignment scanning process. The spatial position of the mold stage and the workpiece stage; and the grating structure of the first alignment mark branch of the mask alignment mark on the workpiece stage reference plate is perpendicular to the radial direction of the workpiece stage, and the grating structure of the third alignment mark branch is parallel to the workpiece The radial direction of the table; the method for aligning the lithographic apparatus comprises the following steps: (1) using the second alignment mark branch on the workpiece table reference plate to the aerial image of the second alignment mark branch of the alignment mark on the mask Perform a rough capture scan to obtain the approximate position of the mask alignment mark; (2) Use the first alignment mark branch on the workpiece table reference plate to perform an aerial image of the corresponding alignment mark branch on the mask along the radial direction of the workpiece table Rough scanning, to obtain the radial coarse alignment position between the two, use the first alignment mark branch on the workpiece table reference plate to perform rough scanning on the aerial image of the corresponding alignment mark branch on the mask along the radial direction of the workpiece table, to obtain The radial coarse alignment position between the two; (3) through the calculation of the radial precise alignment position, the tangential scanning center angle corresponding to the tangential scanning center point of the third alignment mark branch on the workpiece table reference plate is obtained, through Rotate the third alignment mark branch on the reference plate of the workpiece table, and roughly scan the spatial image of the corresponding alignment mark branch on the mask along the tangential direction, and obtain the third alignment mark branch on the workpiece table and the corresponding alignment mark branch on the mask. The included angle of the tangential coarse alignment position between the branches of the alignment mark; (4) after the adjustment of the included angle of the tangential coarse alignment position, the radial coarse alignment position is used as the center of the radial alignment fine scanning of the workpiece table position, use the first alignment mark branch on the workpiece table reference plate to fine-scan the aerial image of the corresponding alignment mark branch on the mask in the radial direction, and obtain the first alignment mark branch on the workpiece table and the corresponding alignment mark branch on the mask. (5) use the radial coarse alignment position to calculate and adjust the first alignment mark branch along the radial direction of the workpiece table, and use the tangential coarse alignment position The included angle is the center included angle of the workpiece table alignment rotation scanning, the third alignment mark branch on the reference plate of the rotating work table is opposite to the corresponding alignment mark branch on the mask The spatial image is finely scanned along the tangential direction to obtain the tangential precise alignment position angle between the third alignment mark branch on the workpiece table and the corresponding alignment mark branch on the mask; (6) use steps (4) and (5) The obtained radial precise alignment position and the angle between the tangential precise alignment position are synthesized, the alignment position is obtained by correction, and the spatial imaging center of the mask alignment mark on the mask is obtained in the workpiece table coordinate system (7) Repeat steps (1) to (6) to obtain the spatial alignment coordinate positions of several mask alignment marks on the mask in the workpiece table coordinate system, and use these spatial alignment coordinate positions to calibrate the light The coordinate position of the central position of the spatial image of the exposure mask pattern in the engraving device under the coordinate system of the workpiece table.

Yet another solution of the present invention is to provide a method for aligning a lithographic apparatus using the above-mentioned mask alignment mark, including the following steps: (a) using the second alignment mark in the mask alignment mark on the workpiece stage reference plate The marking branch performs a rough capture scan on the aerial image of the second alignment marking branch in the alignment mark on the mask, and uses the radiation information detected by the scanning, the mask position information and the workpiece table position information to calculate, and obtain the transmission pair The coarse center position of the alignment mark combination; (b) use the first alignment mark branch on the workpiece table reference plate to perform single-layer or multi-layer rough scanning of the aerial image of the corresponding alignment mark branch on the mask along the direction perpendicular to it , using the radiation information detected by scanning, the position information of the mask and the position information of the workpiece table to calculate, and obtain the distance along the scanning direction between the first alignment mark branch on the reference plate of the work table and the corresponding alignment mark branch on the mask. Coarse alignment space position information; (c) through the rough alignment position calculation of the first alignment mark branch on the mask and the workpiece table reference plate, update the center position of the third alignment mark branch in the vertical scanning direction, and use the workpiece The third alignment mark branch of the stage reference plate performs a single-layer or multi-layer rough scan on the third alignment mark branch on the mask, and uses the radiation information detected by scanning, the third alignment mark branch of the mask and the corresponding workpiece stage Calculate the position information of the alignment mark branch of the reference plate along the scanning direction, and obtain the rough alignment space position information along the scanning direction between the third alignment mark branch on the reference plate of the workpiece table and the corresponding alignment mark branch on the mask (d) calculate the scanning center position of the corresponding spatial image of the first alignment mark branch on the mask with the coarse alignment position between the first and third alignment mark branches on the workpiece table reference plate and the mask, and use the workpiece The first alignment mark branch on the stage reference plate performs fine scanning on the aerial image of the corresponding alignment mark branch on the mask along a direction approximately perpendicular to the alignment grating in the alignment mark branch, and uses the radiation information detected by scanning Calculate with the mask position information and the workpiece table position information to obtain the precise alignment position between the reference plate on the workpiece table and the first alignment mark branch on the mask along the approximate scanning direction; (e) use the workpiece table reference The fine alignment position between the first alignment mark branch on the plate and the mask and the rough alignment position between the third alignment mark branch calculate the scanning center position of the aerial image corresponding to the third alignment mark branch on the mask plate, and use the workpiece The third alignment mark branch on the stage reference plate finely scans the aerial image of the corresponding alignment mark branch on the mask along the direction approximately perpendicular to the alignment grating in the alignment mark branch, and uses the radiation information detected by scanning and The mask position information and the workpiece table position information are calculated to obtain the precise alignment position between the reference plate on the workpiece table and the third alignment mark branch on the mask along the approximate scanning direction; (f) use steps (d) and ( e) Synthesize the obtained precise alignment positions of the first and third alignment mark branches on the mask, correct the alignment positions, and obtain the spatial imaging center of the combination of transmission alignment marks on the mask under the workpiece table coordinate system Coordinate position; (g) Repeat steps (a) to (f) to obtain several mask alignment marks on the mask at the coordinates of the workpiece table space alignment coordinate positions under the coordinate system, and use these space alignment coordinate positions to calculate and calibrate the coordinate position of the center position of the spatial image of the exposure mask pattern in the lithography device under the workpiece table coordinate system.

Compared with the prior art, due to the use of the symmetrical high-capture high-contrast mask alignment mark and its alignment method of the present invention, the ability to capture the aerial image of the alignment mark in the alignment scan and the alignment scan generated alignment can be improved. The contrast of information and its signal-to-noise ratio, the method can improve the efficiency of alignment scanning, achieve a high alignment position repeatability, realize the high capture probability of marker imaging of alignment scanning, and improve the efficiency of alignment scanning.

Description of drawings

Through the following description of specific embodiments of the present invention in conjunction with the accompanying drawings, the purpose, specific structural features and advantages of the invention can be further understood. Among them, the attached figure is:

FIG. 1 is a schematic structural diagram of an alignment system of a lithography apparatus.

FIG. 2 is a schematic structural diagram of the mask alignment mark of the present invention.

Fig. 3 is a schematic diagram of the alignment and calibration method.

FIG. 4 is a flow chart of the alignment method according to the second embodiment of the present invention.

Detailed ways

The mask alignment mark and alignment method of the present invention will be further described in detail below.

Fig. 1 is the structure schematic diagram of the aligning system of lithography apparatus, among the figure 4 is a mask, has mask pattern (comprising exposure mask pattern and mask alignment mark 5) on it, 9 is the workpiece to be photoetched, mask The mold pattern irradiation window 2 and its control board 3 are used to form a window to transmit the radiation 1 to the mask alignment mark 5 to form a transmission image; the projection system 8 is used to project the transmission image to form an aerial image, and use the workpiece table reference The radiation sensor 12 below the plate mark 11 detects the aerial image; the radiation sensor 12 is used to detect the radiation information of the aerial image after passing through the workpiece stage reference plate mark 12; the mask stage position detector 7 and the workpiece stage position detector 13 respectively detect Align the spatial positions of the mask table 6 and the workpiece table 10 during the scanning process. By calculating the relationship model parameters between the radiation information and the relative position between the mask 4 and the workpiece table 10, the alignment information can be obtained from the model, and the alignment information includes information related to the combination of marks on the workpiece table and the position of the sensor, The radiation information includes any one of light amplitude intensity information, light energy information, and phase information, or a combination of phase information and the other two types of information.

Example 1

A mask alignment mark placed on the mask of the mask table and the reference plate of the workpiece table is a transmission alignment mark combination composed of a plurality of alignment mark branches, and the mark combination is used to provide The mask is optically aligned.

As shown in FIG. 2a and FIG. 2b, the mask alignment mark includes a first alignment mark branch 20a, a second alignment mark branch 30 and a third mark branch 20b, the first and third alignment mark branches 20a, 20b are mutually rotated by 90°; the graphics of the second alignment mark branch 30 in the transmission alignment mark on the workpiece table reference plate are distributed in the shape of square transmission holes, and the other two alignment mark branches 20a and 20b are used for alignment scanning Before, the aerial image corresponding to the second alignment mark branch 30 in the transmission alignment mark on the mask is scanned by scanning the aerial image corresponding to the second alignment mark branch 30 in the transmission alignment mark on the work table reference plate, which is used for the transmission alignment mark on the mask. The aerial image corresponding to the first and third alignment mark branches 20a, 20b in the alignment mark is roughly positioned, so that the other two alignment mark branches 20a, 20b on the workpiece table reference plate are used to transmit the alignment mark on the mask In the process of aligning and scanning the other two alignment mark branches respectively or at the same time, it can completely contain and receive the aerial image formed by the second alignment mark branch 30 in the transmission alignment mark on the mask, and use the alignment The projected aerial image corresponding to the second alignment mark branch 30 in the transmission alignment mark combination on the mask obtained during the scanning process passes through the radiation information formed by the transmission alignment mark on the reference plate of the workpiece corresponding to the second alignment mark branch , to normalize the radiation information obtained by performing alignment scanning on some or all of the alignment mark branches in the transmission alignment mark of the workpiece table reference plate.

As shown in Figure 2c, the first and third alignment mark branches 20a/20b are composed of first, second and third grating mark structures 21-23 arranged side by side along the direction perpendicular to the grating, wherein the first and third pair The quasi-grating mark structures 21, 23 are exactly the same, and are distributed on both sides of the second alignment grating mark structure 22, and the length of the second alignment grating mark structure 22 is compared with that of the first and third alignment grating mark structures 21, 23 Inconsistent, its length is 1.2 times to 100 times that of the first and third alignment grating mark structures 21, 23, and the preferred ratio also includes 1.5 times, 2 times, 5 times, 10 times, 20 times or 50 times. Another option is that the lengths of the first and third alignment grating mark structures 21, 23 are 1.2 to 100 times that of the second alignment grating mark structure 22, and preferred ratios also include 1.5 times, 2 times, and 5 times. times, 10 times, 20 times or 50 times. The purpose of this design is to improve the capture ability and the contrast ratio of radiation transmitted energy.

2a-2c, the grating mark structures 21-23 of the first and third alignment mark branches 20a, 20b are further subdivided into three small gratings, and the transmission alignment marks on the workpiece table reference plate correspond to the first 1. The duty cycle of all the grating mark structures of the third alignment mark branch 20a, 20b is not equal to the duty cycle of all the grating mark structures in the transmission alignment mark on the mask, while on the workpiece table reference plate and on the mask The duty ratios of the fine gratings inside all the grating mark structures of the first and third alignment mark branches 20a and 20b in the transmission alignment mark may be the same or different, which is determined according to the alignment signal modulation and measurement requirements.

Using the transmission alignment mark can increase the capture range by more than 10 times, increase the signal contrast by more than 2 times, and improve the signal-to-noise ratio by more than 2 times, thereby improving the alignment accuracy of the lithography device and expanding the accuracy of the lithography device. The stability of alignment improves the efficiency of mask alignment and other measurements.

Example 2

A method for aligning a photolithography device. In the alignment system of the lithography apparatus shown in FIG. 1 , the alignment position is obtained from the model by calculating the parameters of the relationship model between the radiation and the relative position between the mask and the workpiece table.

The flow of the mask alignment method using the above-mentioned mask alignment marks will be described in detail below with reference to FIG. 1 to FIG. 4 . Point O in Figure 3 is the geometric center of the workpiece table, and the specific steps are as follows:

1. Use the second alignment mark branch 30 in the transmission alignment mark 12 on the workpiece table reference plate to perform a rough scan on the second alignment mark branch 30 in the transmission alignment mark 5 on the mask to capture the entire transmission alignment mark, The approximate position of the transmission alignment mark is obtained, wherein the three alignment mark branches of the transmission alignment mark on the work table reference plate and the mask are arranged radially with the work table geometric center O;

2. Use the alignment mark branch 20a whose grating structure on the workpiece table reference plate is approximately perpendicular to the radial direction of the workpiece table to perform a rough scan on the aerial image of the corresponding alignment mark branch on the mask along the radial direction. If the angle Θ between the aerial image of the alignment mark branch and the mark on the reference plate of the workpiece table changes less than 50 microradians, it can be considered that the alignment radiation information of the vernier type Moire fringe is obtained; if the angle Θ is greater than 50 In addition to the vernier-type moiré fringe alignment radiation information, the signal generated by the scan also has horizontal moiré fringe alignment radiation information. The above-mentioned alignment radiation information and the grating structure on the workpiece table reference plate are perpendicular to the workpiece. The relative position information between the alignment mark branch 20a in the radial direction of the stage and the spatial image of the corresponding alignment mark branch on the mask is aligned and calculated to obtain the alignment mark branch 20a whose grating structure on the workpiece stage is perpendicular to the radial direction of the workpiece stage and the radial coarse alignment position B between the corresponding alignment mark branches on the mask;

3. Use the alignment mark branch 20b whose grating structure on the reference plate of the workpiece table is approximately parallel to the radial direction of the workpiece table to roughly scan the spatial image of the corresponding alignment mark branch on the mask along the tangential direction, and take the geometric center O of the workpiece table as The center of the circle, extending the distance between the centers of the first and third alignment mark branches in the above-mentioned transmission alignment mark combination with the above-mentioned precise radial alignment position as the direction, obtains the center point C of the tangential scanning, and uses the corresponding tangential point C The alignment angle is taken as the central angle, and a rough scan is performed first. In addition to the vernier-type moiré fringe alignment radiation information, the alignment radiation information generated by the scan also has horizontal moiré fringe alignment radiation information. Using the above alignment radiation information and The relative position information between the alignment mark branch 20b with the grating structure on the workpiece table reference plate approximately parallel to the radial direction of the work table and the corresponding alignment mark branch on the mask is aligned and calculated to obtain the tangential coarse alignment position Angle;

4. After adjusting the included angle of the tangential coarse alignment position, take the above-mentioned radial coarse alignment position as the center position of the radial alignment fine scanning of the workpiece table, and use the grating structure on the reference plate of the workpiece table to be approximately perpendicular to the radial direction of the workpiece table. The alignment mark branches 20a of the corresponding alignment mark branches on the mask are fine-scanned along the radial direction, and the fine scan can be the spatial imaging of multiple lines on the mask on the workpiece table reference plate, or It can be the spatial imaging of the isolated lines on the mask on the reference plate of the workpiece table; if there is an included angle between the alignment mark branch imaging on the corresponding mask and the sensor mark, the signal generated by scanning will have no vernier type In addition to the Moiré fringe alignment radiation information, there is also the transverse Moiré fringe alignment radiation information, using the above-mentioned alignment radiation information and the alignment mark branch 20a whose grating structure is perpendicular to the radial direction of the workpiece table on the workpiece table reference plate and corresponding to the mask. The relative position information between the spatial images of the alignment mark branches is aligned and calculated, and the radial direction between the alignment mark branch 20a with the grating structure on the workpiece table perpendicular to the radial direction of the work table and the corresponding alignment mark branch on the mask is obtained. Accurate alignment position A;

5. Take the included angle of the tangential coarse alignment position in step 3 as the center included angle of the workpiece table alignment rotation scanning, and align the mask with the alignment mark branch 20b whose grating structure on the reference plate of the workpiece table is approximately parallel to the radial direction of the workpiece table The spatial image of the corresponding alignment mark branch is fine-scanned along the tangential direction. In addition to the vernier-type moiré fringe alignment radiation information, the signal generated by the scan still has horizontal moiré fringe alignment radiation information. The fine scan can It is the spatial imaging of multiple lines on the reference plate of the workpiece table, or the spatial imaging of isolated lines on the reference plate of the workpiece table. The above-mentioned alignment radiation information and the grating structure on the reference plate of the workpiece table are approximately parallel to The relative position information between the alignment mark branch 20b in the radial direction of the workpiece table and the spatial image of the corresponding alignment mark branch on the mask is aligned and calculated to obtain the angle offset θ of the tangential precise alignment position, and the corresponding position point is D;

6. Use the radial precise alignment position A obtained in step 4 and the tangential precise alignment position angle θ obtained in step 5 to perform alignment position synthesis, that is, integrate the radial point A and the tangential point D, and correct it to obtain The alignment position is to obtain the coordinate position of the spatial imaging center of the transmission alignment mark combination on the mask under the coordinate system of the workpiece table.

7. Repeat steps 1 to 6 to obtain the spatial alignment coordinate positions of several transmission alignment marks on the mask combined in the workpiece table coordinate system, and use these spatial alignment coordinate positions to calculate and calibrate the exposure mask pattern in the lithography device The coordinate position of the center in the workpiece table coordinate system.

Example 3

Referring to Fig. 1 to Fig. 4, another method for aligning a lithographic apparatus of the present invention includes the following steps:

(a) Use the second alignment mark branch in the mask alignment mark on the workpiece table reference plate to perform rough capture scanning on the aerial image of the second alignment mark branch in the alignment mark on the mask, and use the detected calculating the radiation information, the position information of the mask and the position information of the workpiece table to obtain the coarse center position of the combination of transmission alignment marks;

(b) Use the first alignment mark branch on the workpiece table reference plate to perform single-layer or multi-layer rough scanning of the aerial image of the corresponding alignment mark branch on the mask in a direction perpendicular to it, and use the detected Calculating the radiation information, mask position information, and workpiece table position information to obtain rough alignment space position information along the scanning direction between the first alignment mark branch on the work table reference plate and the corresponding alignment mark branch on the mask;

(c) Through the rough alignment position calculation of the first alignment mark branch on the mask and the workpiece table reference plate, update the center position of the third alignment mark branch in the vertical scanning direction, and use the third alignment mark on the workpiece table reference plate The branch performs a single-layer or multi-layer rough scan on the third alignment mark branch on the mask, and uses the radiation information detected by scanning and the third alignment mark branch of the mask and the alignment mark branch of the corresponding workpiece table reference plate to scan along the The position information in the direction is calculated to obtain the rough alignment space position information along the scanning direction between the third alignment mark branch on the workpiece table reference plate and the corresponding alignment mark branch on the mask;

(d) Calculate the scanning center position of the aerial image corresponding to the first alignment mark branch on the mask based on the coarse alignment position between the first and third alignment mark branches on the workpiece table reference plate and the mask, and use the workpiece table The first alignment mark branch on the reference plate finely scans the aerial image of the corresponding alignment mark branch on the mask along a direction approximately perpendicular to the alignment grating in the alignment mark branch, and uses the radiation information detected by scanning and The mask position information and the workpiece table position information are calculated to obtain the precise alignment position between the reference plate on the workpiece table and the branch of the first alignment mark on the mask along the approximate scanning direction;

(e) Calculate the correspondence of the third alignment mark branch on the mask plate with the fine alignment position between the first alignment mark branch on the workpiece table reference plate and the mask and the rough alignment position between the third alignment mark branch At the scanning center position of the aerial image, use the third alignment mark branch on the workpiece table reference plate to fine-scan the aerial image of the corresponding alignment mark branch on the mask along the direction approximately vertical to the alignment grating in the alignment mark branch, using Scanning and calculating the detected radiation information, mask position information, and workpiece table position information to obtain an accurate alignment position between the reference plate on the workpiece table and the third alignment mark branch on the mask along the approximate scanning direction;

(f) Synthesize the precise alignment positions of the first and third alignment mark branches on the mask obtained in steps (d) and (e), correct the alignment positions, and obtain the combination of transmission alignment marks on the mask The coordinate position of the spatial imaging center in the workpiece table coordinate system;

(g) Repeat steps (a) to (f) to obtain the spatial alignment coordinate positions of several mask alignment marks on the mask in the workpiece table coordinate system, and use these spatial alignment coordinate positions to calculate and calibrate the lithography device The coordinate position of the central position of the spatial image of the exposure mask pattern in the coordinate system of the workpiece table.

By using the above mask alignment method, the entire mask alignment scanning time can be shortened by more than 8 seconds compared with the prior art, thereby having better mask alignment efficiency.

The above descriptions are only based on preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. Any equivalent changes or substitutions known in the technical field to the implementation steps of the present invention will not exceed the disclosure and protection scope of the present invention.

Claims (16)

1, a kind of mask alignment mark, place on the mask of mask platform respectively and on the datum plate of work stage, be used to provide the mask optical alignment, described mask alignment mark comprises first, the second and the 3rd alignment mark branch, wherein, the poroid distribution of transmission that is square of the second alignment mark branch, the first and the 3rd alignment mark branch is about the half-twist replacement each other of the second alignment mark branch, and the first and the 3rd alignment mark branch is respectively by first, the second and the 3rd grating marker structure is along constituting side by side with the grating vertical direction, wherein the first and the 3rd grating marker structure is identical, be distributed in the second grating marker structure both sides, it is characterized in that: described first is different with the length of the second grating marker structure with the length of the 3rd grating marker structure.

2, mask alignment mark as claimed in claim 1, it is characterized in that: the length of the second grating marker structure is 1.2 times to 100 times of the first and the 3rd grating marker structure, and perhaps the length of the first and the 3rd grating marker structure is 1.2 times to 100 times of the second grating marker structure.

3, mask alignment mark as claimed in claim 2 is characterized in that: the length of the second grating marker structure is 1.5 times, 2 times, 5 times, 10 times, 20 times or 50 times of the first and the 3rd grating marker structure; Perhaps the length of the first and the 3rd grating marker structure is 1.5 times, 2 times, 5 times, 10 times, 20 times or 50 times of the second grating marker structure.

4, mask alignment mark as claimed in claim 1 is characterized in that: the grating in described first, second and the 3rd grating marker structure is subdivided into three tiny gratings.

5, mask alignment mark as claimed in claim 4, it is characterized in that: the dutycycle of all grating marker structures of corresponding the first, the 3rd alignment mark branch is identical with the dutycycle of corresponding all grating marker structures in the mask alignment mark on the mask in the mask alignment mark on the work stage datum plate, but the dutycycle difference of tiny grating is wherein determined according to registration signal modulation and measurement requirement.

6, adopt the method for carrying out the lithographic equipment aligning as each described mask alignment mark in the claim 1～5, described lithographic equipment has an alignment system, and this alignment system comprises: radiation-generating machine, mask graph illumination window and control panel thereof, mask, mask platform, mask platform position sensor, optical projection system, work stage and work stage datum plate mark, work stage position sensor and radiation detection sensor; Wherein

Comprise exposure mask pattern and several mask alignment mark on the mask;

Mask graph illumination window and control panel thereof form transmission window, and the radiation transmission that radiation-generating machine is produced forms the transmission picture on exposure mask pattern and mask alignment mark;

Optical projection system forms aerial image with this transmission picture projection, and surveys this aerial image with the radiation detection sensor of workpiece stage fiducial plate mark below;

The radiation information of radiation detection sensor aerial image after through the transmission of work stage datum plate mark, described radiation information comprise in radiation magnitude strength information, emittance information, the radiation phase information combination of any one or phase information and other two kinds of information;

Mask platform position sensor and work stage position sensor are surveyed the mask platform in the alignment scanning process and the locus of work stage respectively;

And the optical grating construction of the first alignment mark branch of the mask alignment mark on the work stage datum plate perpendicular to work stage radially, and the optical grating construction of the 3rd alignment mark branch is parallel to work stage radially; It is characterized in that described lithographic equipment alignment methods comprises the steps:

(1) with the second alignment mark branch on the workpiece stage fiducial plate aerial image of the second alignment mark branch of alignment mark on the mask is slightly caught scanning, obtain the approximate location of mask alignment mark;

(2) radially the aerial image of alignment mark branch corresponding on the mask is carried out coarse scanning with the first alignment mark branch on the workpiece stage fiducial plate along work stage, obtain radially coarse alignment position between the two;

(3) by radially accurately aligned position calculating, obtain the tangential scanning center angle of the tangential sweep center point correspondence of the 3rd alignment mark branch on the work stage datum plate, by the 3rd alignment mark branch on the rotational workpieces stage fiducial plate, aerial image to alignment mark branch corresponding on the mask tangentially carries out coarse scanning, obtains on the work stage the tangential coarse alignment position angle between alignment mark branch corresponding in the 3rd alignment mark branch and mask;

(4) through after the angle adjustment of tangential coarse alignment position, with described radially coarse alignment position is the center that work stage is radially aimed at smart scanning, radially the aerial image of alignment mark branch corresponding on the mask is carried out essence scanning with the first alignment mark branch on the workpiece stage fiducial plate, obtain on the work stage the radially accurate aligned position between alignment mark branch corresponding in the first alignment mark branch and mask;

(5) radially adjust the first alignment mark branch with described radially coarse alignment position calculation and along work stage, with described tangential coarse alignment position angle is the center angle that work stage is aimed at rotation sweep, the 3rd alignment mark branch on the rotational workpieces stage fiducial plate tangentially carries out essence scanning to the aerial image of alignment mark branch corresponding on the mask, obtains on the work stage the tangential accurate aligned position angle between alignment mark branch corresponding in the 3rd alignment mark branch and mask;

(6) carry out comprehensively with tangential accurately aligned position angle with step (4) and (5) resulting radially accurate aligned position, proofread and correct and obtain aligned position, obtain the coordinate position of aerial image center under worktable coordinate system of the mask alignment mark on the mask;

(7) repeating step (1)～(6), obtain the spacial alignment coordinate position of several mask alignment mark under worktable coordinate system on the mask, with the coordinate position of center under worktable coordinate system of exposure mask pattern aerial image in these spacial alignment coordinate position alignment light engraving devices.

7, lithographic equipment alignment methods as claimed in claim 6 is characterized in that: three alignment mark branches of the mask alignment mark on work stage datum plate and the mask with the work stage geometric center along its radial array.

8, lithographic equipment alignment methods as claimed in claim 6, it is characterized in that: in the step (1), utilization slightly catch scanning probe to radiation information and mask position information and work stage positional information calculate, obtain the approximate location of transmission alignment mark combination.

9, lithographic equipment alignment methods as claimed in claim 6, it is characterized in that: in the step (2), if the variable angle that exists between the mark on the aerial image of alignment mark branch and the work stage datum plate on the corresponding mask, can think then that what obtain is vernier type Moire fringe aligning radiation information less than 50 microradians; If this angle is greater than 50 microradians, then scan in the signal that generates except there being the vernier type Moire fringe to aim at the radiation information, also exist horizontal Moire fringe to aim at radiation information, the utilization scanning probe to radiation information and mask position information and work stage positional information calculate, obtain the radially coarse alignment position between alignment mark branch corresponding on the first alignment mark branch of mask alignment mark on the work stage datum plate and the mask.

10, lithographic equipment alignment methods as claimed in claim 6, it is characterized in that: the tangential sweep center point of step (3) is to be the center of circle with the work stage geometric center, with described radially accurately aligned position be that direction extends that the first and the 3rd alignment mark divides the distance between branch center to obtain in the described transmission alignment mark combination.

11, lithographic equipment alignment methods as claimed in claim 10, it is characterized in that: in the aligning radiation information that coarse scanning generated in the step (3) except there being the vernier type Moire fringe to aim at the radiation information, also exist horizontal Moire fringe to aim at radiation information, calculate with the tangential position angle information of described aligning radiation information and mask alignment mark branch and corresponding work stage datum plate alignment mark branch.

12, lithographic equipment alignment methods as claimed in claim 6, it is characterized in that: the described smart scanning of step (4) is to the aerial image of a plurality of lines on the mask on work stage datum plate face, or to isolating the scanning of the aerial image of lines on work stage datum plate face on the mask.

13, lithographic equipment alignment methods as claimed in claim 12, it is characterized in that: in the step (4), if alignment mark is branched off between picture and the corresponding work stage datum plate alignment mark branch and has angle on the mask, then scan in the signal that generates except there being the vernier type Moire fringe to aim at the radiation information, also exist horizontal Moire fringe to aim at radiation information, calculate with described aligning radiation information and mask position information and work stage positional information, obtain on the work stage datum plate the radially accurate aligned position between alignment mark branch corresponding in the first alignment mark branch and mask.

14, lithographic equipment alignment methods as claimed in claim 6, it is characterized in that: the described smart scanning of step (5), in the signal that generates except there being the vernier type Moire fringe to aim at the radiation information, still exist horizontal Moire fringe to aim at radiation information, this essence scanning is to the aerial image of a plurality of lines on work stage datum plate face, or to the isolated aerial image of lines on work stage datum plate face.

15, lithographic equipment alignment methods as claimed in claim 14, it is characterized in that: aim at calculating with the relative position information between the aerial image of alignment mark branch corresponding on the 3rd alignment mark branch on described aligning radiation information and the work stage datum plate and the mask, obtain tangential accurately aligned position angle.

16, adopt the method for carrying out the lithographic equipment aligning as each described mask alignment mark in the claim 1～5, described lithographic equipment has an alignment system, and this alignment system comprises: radiation-generating machine, mask graph illumination window and control panel thereof, mask, mask platform, mask platform position sensor, optical projection system, work stage and work stage datum plate mark, work stage position sensor and radiation detection sensor; Wherein

Comprise exposure mask pattern and several mask alignment mark on the mask;

Mask graph illumination window and control panel thereof form transmission window, and the radiation transmission that radiation-generating machine is produced forms the transmission picture on exposure mask pattern and mask alignment mark;

Optical projection system forms aerial image with this transmission picture projection, and surveys this aerial image with the radiation detection sensor of workpiece stage fiducial plate mark below;

The radiation information of radiation detection sensor aerial image after through the transmission of work stage datum plate mark, described radiation information comprise in radiation magnitude strength information, emittance information, the radiation phase information combination of any one or phase information and other two kinds of information;

Mask platform position sensor and work stage position sensor are surveyed the mask platform in the alignment scanning process and the locus of work stage respectively;

It is characterized in that described lithographic equipment alignment methods comprises the steps:

(a) with the second alignment mark branch in the mask alignment mark on the workpiece stage fiducial plate aerial image of the second alignment mark branch in the alignment mark on the mask is slightly caught scanning, the utilization scanning probe to described radiation information and mask position information and work stage positional information calculate, obtain the thick center of transmission alignment mark combination;

(b) along direction the aerial image of alignment mark branch corresponding on the mask is carried out the single or multiple lift coarse scanning with the first alignment mark branch on the workpiece stage fiducial plate perpendicular to it, the utilization scanning probe to described radiation information and mask position information and work stage positional information calculate, obtain on the work stage datum plate the coarse alignment spatial positional information between alignment mark branch corresponding in the first alignment mark branch and mask along the direction of scanning;

(c) the coarse alignment position calculation by the first alignment mark branch on mask and the work stage datum plate, upgrade the center of the 3rd alignment mark branch vertical scanning direction, with workpiece stage fiducial plate the 3rd alignment mark branch the 3rd alignment mark branch on the mask is carried out the single or multiple lift coarse scanning, the utilization scanning probe to described radiation information and mask the 3rd alignment mark branch and corresponding work stage datum plate alignment mark branch calculate along the positional information on the direction of scanning, obtain on the work stage datum plate the coarse alignment spatial positional information between alignment mark branch corresponding in the 3rd alignment mark branch and mask along the direction of scanning;

(d) with on described work stage datum plate and the mask first with the 3rd alignment mark branch between coarse alignment position calculation mask on the scanning center position of the corresponding aerial image of the first alignment mark branch, scan along the aerial image of alignment mark branch corresponding on the mask being carried out essence with the first alignment mark branch on the workpiece stage fiducial plate approximately perpendicular to the direction of aiming at grating in the alignment mark branch, the utilization scanning probe to described radiation information and mask position information and work stage positional information calculate, obtain on the work stage on the datum plate and mask between the first alignment mark branch along the accurate aligned position on the approximate direction of scanning;

(e) with the scanning center position of the corresponding aerial image of the 3rd alignment mark branch on the coarse alignment position calculation mask plate between accurate aligned position between the first alignment mark branch on described work stage datum plate and the mask and the 3rd alignment mark branch, along the direction of aiming at grating in the near normal alignment mark branch aerial image of alignment mark branch corresponding on the mask being carried out essence with the 3rd alignment mark branch on the workpiece stage fiducial plate scans, the utilization scanning probe to described radiation information and mask position information and work stage positional information calculate, obtain on the work stage on the datum plate and mask between the 3rd alignment mark branch along the accurate aligned position on the approximate direction of scanning;

(f) with step (d) and (e) on the resultant mask the accurate aligned position of the first and the 3rd alignment mark branch carry out comprehensively, correction obtains aligned position, obtains the coordinate position of aerial image center under worktable coordinate system of transmission alignment mark combination on the mask;

(g) repeat to obtain the spacial alignment coordinate position of several mask alignment mark under worktable coordinate system on the mask, with the coordinate position of center under worktable coordinate system of exposure mask pattern aerial image in these spacial alignment coordinate positions calculating and the alignment light engraving device with step (a)～(f).

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