Dynamic large-area focusing and leveling method of a photoetching machine

Abstract

The application discloses a dynamic large-area focusing and leveling mode of a photoetching machine. In the process that a mask table carries a mask from an initial position to an exposure alignment position, the mask table passes a first measuring area at a uniform speed, and global focusing and leveling work of the mask is completed in the first measuring area. In the process that a worktable carries a workpiece from an upper piece position to an exposure position, the worktable passes a second measuring area at a uniform speed, and focusing and leveling work of i exposure fields of the workpiece is completed in the second measuring area. The i exposure fields on the workpiece enter the exposure position one by one to perform fine focusing and leveling, so that each exposure field reaches the best focal plane of an objective lens and then performs exposure. The dynamic large-area focusing and leveling mode of the photoetching machine realizes dynamic focusing and leveling work in the process that the mask reaches the exposure alignment position and dynamic large-area focusing and leveling work in the process that the workpiece moves to the exposure position, shortens the overall focusing and leveling time before exposure, and improves exposure precision.

Description

Technical Field

[0001] This invention relates to the field of lithography equipment technology, and in particular to a dynamic large-area focusing and leveling method for lithography machines. Background Technology

[0002] A photolithography machine is a device that transfers a pattern from a photomask onto a workpiece (silicon wafer or glass substrate). In order for the projection lens to clearly project the pattern from the photomask onto the workpiece, it is necessary to measure whether the exposure surface of the workpiece coincides with the focal plane of the projection lens. Therefore, each exposure field of the workpiece needs to be focused and leveled before exposure.

[0003] Current technology employs static field-by-field focusing and leveling. The workpiece is loaded onto the film at the loading position, then moves to the exposure position after acceleration and deceleration. A focusing and leveling sensor scans and measures the first exposure field of the stationary workpiece. The signal processor obtains the surface shape data of this exposure field based on the measurement data. The stage then focuses and levels the first exposure field based on this surface shape data. After focusing and leveling, the first exposure field is exposed. After the first exposure field is exposed, the stage carries the next exposure field to the exposure position, and the above steps are repeated until focusing, leveling, and exposure are completed for all exposure fields. While the current static focusing and leveling method is simple, the focusing and leveling time is long, affecting the overall machine yield. Furthermore, current technology does not focus and level the mask; if the mask is uneven, the exposure accuracy is low.

[0004] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a dynamic large-area focusing and leveling method for lithography machines, which aims to achieve dynamic focusing and leveling of the mask during the process of moving from the initial position to the exposure alignment position and dynamic large-area focusing and leveling of the workpiece during the process of moving from the loading position to the exposure position, thereby shortening the overall focusing and leveling time before exposure and improving the exposure accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A dynamic large-area focusing and leveling method for a lithography machine includes the following steps:

[0008] S1. The mask stage holds the mask in the initial position and begins to step towards the first measurement area;

[0009] S2. The mask stage passes through the first measurement area at a constant speed. The dynamic focusing and leveling sensor performs a global scan measurement of the mask. The signal processor processes the scan information to obtain the surface shape data of the mask.

[0010] S3. The mask stage performs global focusing and leveling on the mask based on the mask's surface shape data.

[0011] S4. After passing through the first measurement area, the mask stage decelerates and moves to the exposure alignment position;

[0012] S5. The worktable carries the workpiece at the upper plate position and begins to step towards the second measurement area;

[0013] S6. The worktable passes through the second measurement area at a constant speed. The dynamic large-area focusing and leveling sensor performs a global scan measurement of the workpiece. The signal processor processes the above scan information to obtain the surface shape data of the i exposure fields of the workpiece, where i is an integer greater than 0.

[0014] S7. The worktable performs global focusing and leveling on each exposure field based on the surface shape data of the i exposure fields of the workpiece.

[0015] S8. After the worktable passes through the second measurement area, it decelerates and moves to the exposure position so that the first exposure field of the workpiece enters the exposure position.

[0016] S9. When the mask reaches the exposure alignment position, the focusing and leveling sensor scans and measures the first exposure field. The signal processor processes the above scanning information to obtain the surface shape data of the first exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the first exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure.

[0017] S10, The worktable carries the workpiece, allowing the next exposure field of the workpiece to enter the exposure position;

[0018] S11. The focusing and leveling sensor scans and measures the next exposure field. The signal processor processes the scan information to obtain the surface shape data of the next exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the next exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure.

[0019] S12. Repeat steps S10 and S11 until all i exposure fields of the workpiece are fully exposed.

[0020] Furthermore, steps S1 and S5 are performed simultaneously.

[0021] Furthermore, during steps S1-S4, the first measurement area is located between the initial position and the exposure alignment position, and the initial position, the first measurement area, and the exposure alignment position are on the same straight line, with the dynamic focus and leveling sensor located within the first measurement area.

[0022] Furthermore, during steps S5-S8, the second measurement area is located between the film loading position and the exposure position, and the film loading position, the second measurement area, and the exposure position are on the same straight line, with the dynamic large-area focusing and leveling sensor located in the second measurement area.

[0023] Furthermore, during steps S1-S2, the mask stage accelerates towards the first measurement area to a certain speed, and then moves at that speed at a constant speed for a period of time before entering the first measurement area.

[0024] Furthermore, during steps S5-S6, the worktable accelerates towards the second measurement area to a certain speed, and then moves at that speed at a constant speed for a period of time before entering the second measurement area.

[0025] Furthermore, in step S2, the number of measurement spots of the dynamic focusing and leveling sensor covering the mask is at least three, and none of them are on the same straight line.

[0026] Furthermore, in step S5, the measurement spot of the dynamic large-area focusing and leveling sensor covers i exposure fields on the workpiece, and the number of measurement spots in each exposure field is at least three, and none of them are on the same straight line.

[0027] Beneficial effects:

[0028] During the process of the photomask moving from the starting position to the exposure alignment position, the photomask stage carries the photomask and moves at a constant speed through the first measurement area. Within the first measurement area, the dynamic focusing and leveling sensor and signal processor obtain the surface shape data of the photomask. The photomask stage then performs focusing and leveling operations on the photomask based on the surface shape data. Similarly, during the process of the workpiece moving from the loading position to the exposure position, the worktable carries the workpiece and moves at a constant speed through the second measurement area. Within the second measurement area, the dynamic large-area focusing and leveling sensor and signal processor obtain the surface shape data of the i exposure fields of the workpiece. The worktable then performs focusing and leveling operations on the i exposure fields of the workpiece based on the surface shape data. This ensures that, while maintaining the flatness of the photomask, the i exposure fields of the workpiece, after fine focusing and leveling, can reach the focal plane of the objective lens for exposure. This achieves focusing and leveling operations before the photomask reaches the exposure alignment position and before each exposure field of the workpiece reaches the exposure position, shortening the overall focusing and leveling time and improving the overall machine yield and exposure accuracy. Attached Figure Description

[0029] Figure 1 This is a flowchart of a dynamic large-area focusing and leveling method for a lithography machine provided by the present invention.

[0030] Figure 2This is a schematic diagram of the mask and workpiece in steps S1-S9 of a dynamic large-area focusing and leveling method for a lithography machine provided by the present invention.

[0031] Figure 3 This invention provides a measurement spot distribution diagram on a photomask in a dynamic large-area focusing and leveling method for a lithography machine.

[0032] Figure 4 This invention provides a measurement spot distribution diagram on a workpiece in a dynamic large-area focusing and leveling method for a lithography machine. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0035] Example

[0036] Please see Figure 1-2 This invention provides a dynamic large-area focusing and leveling method for lithography machines, comprising the following steps:

[0037] S1. The mask stage holds the mask in the initial position and begins to step towards the first measurement area;

[0038] S2. The mask stage passes through the first measurement area at a constant speed. The dynamic focusing and leveling sensor performs a global scan measurement of the mask. The signal processor processes the scan information to obtain the surface shape data of the mask.

[0039] S3. The mask stage performs global focusing and leveling on the mask based on the mask's surface shape data.

[0040] S4. After passing through the first measurement area, the mask stage decelerates and moves to the exposure alignment position;

[0041] S5. The worktable carries the workpiece at the upper plate position and begins to step towards the second measurement area;

[0042] S6. The worktable passes through the second measurement area at a constant speed. The dynamic large-area focusing and leveling sensor performs a global scan measurement of the workpiece. The signal processor processes the above scan information to obtain the surface shape data of the i exposure fields of the workpiece, where i is an integer greater than 0.

[0043] S7. The worktable performs global focusing and leveling on each exposure field based on the surface shape data of the i exposure fields of the workpiece.

[0044] S8. After the worktable passes through the second measurement area, it decelerates and moves to the exposure position so that the first exposure field of the workpiece enters the exposure position.

[0045] S9. When the mask reaches the exposure alignment position, the focusing and leveling sensor scans and measures the first exposure field. The signal processor processes the above scanning information to obtain the surface shape data of the first exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the first exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure.

[0046] S10, The worktable carries the workpiece, allowing the next exposure field of the workpiece to enter the exposure position;

[0047] S11. The focusing and leveling sensor scans and measures the next exposure field. The signal processor processes the scan information to obtain the surface shape data of the next exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the next exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure.

[0048] S12. Repeat steps S10 and S11 until all i exposure fields of the workpiece are fully exposed.

[0049] See Figure 1-2 Before focusing and leveling, if the mask is bent downwards and the workpiece is bent upwards, steps S1-S4 are the dynamic focusing and leveling process of the mask. During the process of the mask stage carrying the mask moving from the initial position to the exposure alignment position, it moves through the first measurement area at a constant speed and completes the global focusing and leveling of the mask in the first measurement area, thereby realizing global dynamic focusing and leveling of the mask. Compared with the existing technology, this improves the exposure accuracy of the mask pattern.

[0050] Steps S5-S8 constitute the dynamic large-area focusing and leveling process of the workpiece. As the worktable carries the workpiece from the loading position to the exposure position, it moves at a constant speed through the second measurement area, completing the focusing and leveling of the workpiece's i exposure fields within this area, thus achieving global dynamic focusing and leveling of the workpiece. The workpiece completes global focusing and leveling during its movement, which, compared to existing technologies, shortens the focusing and leveling time and improves the overall machine yield.

[0051] Steps S9-S12 describe the process of the i exposure fields on the workpiece entering the exposure position for exposure. Each of the i exposure fields on the workpiece enters the exposure position one by one for fine-tuning and leveling, ensuring that each exposure field reaches the optimal focal plane of the objective lens before exposure. Since the workpiece has already completed global focusing and leveling before entering the exposure position, the fine-tuning and leveling of the i exposure fields before exposure is time-efficient and ensures the exposure accuracy of the exposure fields.

[0052] In this embodiment, steps S1 and S5 are performed simultaneously. Since the workpiece is larger than the mask, the focusing and leveling time of the workpiece is longer than that of the mask. Therefore, focusing and leveling the mask at the same time as focusing and leveling the workpiece can further shorten the overall focusing and leveling time and improve the overall machine yield.

[0053] In this embodiment, during steps S1-S4, the first measurement area is located between the initial position and the exposure alignment position, and the initial position, the first measurement area, and the exposure alignment position are on the same straight line. The dynamic focus and leveling sensor is located within the first measurement area. The mask stage performs focus and leveling work along the shortest path from the initial position to the exposure alignment position, further shortening the focus and leveling time of the mask.

[0054] Furthermore, during steps S1-S2, the mask stage accelerates towards the first measurement area to a certain speed and moves at that speed uniformly for a period of time before entering the first measurement area. This ensures that the mask stage remains in a uniform motion state during the dynamic focusing and leveling process of the mask plate. Therefore, the process will not generate additional disturbances due to changes in the speed of the mask stage, thus ensuring the accuracy of the mask plate's focusing and leveling.

[0055] In this embodiment, during steps S5-S8, the second measurement area is located between the film loading position and the exposure position, and the film loading position, the second measurement area, and the exposure position are on the same straight line. The dynamic large-area focusing and leveling sensor is located in the second measurement area. The worktable performs focusing and leveling work along the shortest route from the film loading position to the exposure position, further shortening the focusing and leveling time of the workpiece.

[0056] Furthermore, during steps S5-S6, the worktable accelerates towards the second measurement area to a certain speed and moves at that speed at a constant speed for a period of time before entering the second measurement area. This ensures that the worktable remains in a constant speed state during the dynamic focusing and leveling process of the workpiece. Therefore, the process will not cause additional disturbances due to changes in the speed of the worktable, thus ensuring the accuracy of the workpiece focusing and leveling.

[0057] In this embodiment, in step S2, the measurement spots of the dynamic focusing and leveling sensor cover at least three areas on the mask, and none of them are on the same straight line. (See also...) Figure 3 Taking three measurement spots covering the mask as an example, the three measurement spots are distributed in a triangular pattern on the mask. The dynamic focusing and leveling sensor generates a series of measurement values ​​(Z, Rx, Ry) based on the three measurement spots, and obtains the overall surface shape data of the mask under the processing of the information processor, and fits the most ideal mask posture.

[0058] In this embodiment, in step S5, the measurement spot of the dynamic large-area focusing and leveling sensor covers i exposure fields on the workpiece, with at least three measurement spots in each exposure field, and these spots are not on the same straight line. (See also...) Figure 4 Taking a workpiece with 8 exposure fields and three measurement spots covering each exposure field as an example, the workpiece is divided into 8 exposure fields in a two-column, four-row manner. The three measurement spots on each exposure field are distributed in a triangular manner to cover the exposure field. The dynamic large-area focusing and leveling sensor generates a series of measurement values ​​(Z, Rx, Ry) based on the three measurement spots on each exposure field, and obtains the surface shape data of the 8 exposure fields under the processing of the information processor, and fits the most ideal workpiece posture.

[0059] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A dynamic large area focusing and leveling method for a lithography machine, characterized in that, Includes the following steps: S1. The mask stage holds the mask in the initial position and begins to step towards the first measurement area; S2. The mask stage passes through the first measurement area at a constant speed. The dynamic focusing and leveling sensor performs a global scan measurement of the mask. The signal processor processes the scan information to obtain the surface shape data of the mask. S3. The mask stage performs global focusing and leveling on the mask based on the mask's surface shape data. S4. After passing through the first measurement area, the mask stage decelerates and moves to the exposure alignment position; S5. The worktable carries the workpiece at the upper plate position and begins to step towards the second measurement area; S6. The worktable passes through the second measurement area at a constant speed. The dynamic large-area focusing and leveling sensor performs a global scan measurement of the workpiece. The signal processor processes the above scan information to obtain the surface shape data of the i exposure fields of the workpiece, where i is an integer greater than 0. S7. The worktable performs global focusing and leveling on each exposure field based on the surface shape data of the i exposure fields of the workpiece. S8. After the worktable passes through the second measurement area, it decelerates and moves to the exposure position so that the first exposure field of the workpiece enters the exposure position. S9. When the mask reaches the exposure alignment position, the focusing and leveling sensor scans and measures the first exposure field. The signal processor processes the above scanning information to obtain the surface shape data of the first exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the first exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure. S10, The worktable carries the workpiece, allowing the next exposure field of the workpiece to enter the exposure position; S11. The focusing and leveling sensor scans and measures the next exposure field. The signal processor processes the scan information to obtain the surface shape data of the next exposure field of the workpiece. The worktable performs fine focusing and leveling on the exposure field according to the surface shape data of the next exposure field so that the exposure field reaches the optimal focal plane of the objective lens for exposure. S12. Repeat steps S10 and S11 until all i exposure fields of the workpiece are fully exposed.

2. The dynamic large area focusing and leveling method for lithography machine according to claim 1, wherein, Steps S1 and S5 are performed simultaneously.

3. The dynamic large area focusing and leveling method for lithography machine according to claim 1, wherein, During steps S1-S4, the first measurement area is located between the initial position and the exposure alignment position, and the initial position, the first measurement area, and the exposure alignment position are on the same straight line. The dynamic focus and leveling sensor is located within the first measurement area.

4. The dynamic large area focusing and leveling method for lithography machine according to claim 1, wherein, During steps S5-S8, the second measurement area is located between the upper film position and the exposure position, and the upper film position, the second measurement area, and the exposure position are on the same straight line. The dynamic large-area focusing and leveling sensor is located in the second measurement area.

5. The dynamic large area focusing and leveling method for lithography machine according to claim 3, wherein, During steps S1-S2, the mask stage accelerates towards the first measurement area to a certain speed, and then moves at that speed at a constant speed for a period of time before entering the first measurement area.

6. The dynamic large-area focusing and leveling method for lithography machines according to claim 4, characterized in that, During steps S5-S6, the workbench accelerates towards the second measurement area to a certain speed, and then moves at that speed at a constant speed for a period of time before entering the second measurement area.

7. The dynamic large-area focusing and leveling method for lithography machines according to claim 1, characterized in that, In step S2, the number of measurement spots of the dynamic focusing and leveling sensor covering the mask is at least three, and none of them are on the same straight line.

8. The dynamic large-area focusing and leveling method for lithography machines according to claim 1, characterized in that, In step S5, the measurement spot of the dynamic large-area focusing and leveling sensor covers i exposure fields on the workpiece, and each exposure field has at least three measurement spots, none of which are on the same straight line.

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