CN115343917A - Method and device for improving photoetching precision - Google Patents

Abstract

The application provides a method and a device for improving photoetching precision, which relate to the technical field of photoetching, and are characterized in that a laser cutting process is introduced, the high-precision characteristic of the laser cutting process is utilized to realize the manufacture of a standard graph on a standard chip, and then the calibration of the correct placement position (production position) of a product substrate is quickly completed in a mode of overlaying and aligning the standard graph on the standard chip and a photoetching graph on a photoetching mask, so that the calibration times and the calibration time in the calibration process can be effectively reduced, and then the product substrate is conveniently placed at the calibrated production position in the actual production process, so that the high-precision alignment of the product substrate and the photoetching mask is realized, and further the photoetching precision is improved.

Description

Method and device for improving photoetching precision

Technical Field

The present application relates to the field of lithography technologies, and in particular, to a method and an apparatus for improving lithography precision.

Background

In IC circuit manufacturing, a complete chip is usually subjected to tens to twenty times of photolithography, and therefore, the relative positional accuracy between the photolithography pattern and the product substrate is very important in the whole chip automatic photolithography.

At present, a mechanical arm of a photoetching machine carries a product substrate to a pre-alignment platform from a blocking plug, photoetching characteristics on the product substrate are identified, and the product substrate is automatically carried to the photoetching platform after the center of the product substrate is found out, but the X, Y shaft motion precision can only reach the level within 50um in the best state, and the condition of angular rotation deviation exists, so that the product substrate has deviation in the direction of X, Y and large angular rotation relative to a photoetching mask, and the photoetching precision is poor.

Disclosure of Invention

The present application aims to provide a method and an apparatus for improving lithography precision, so as to solve the problem of poor lithography precision in the prior art.

In order to achieve the above purpose, the technical solutions adopted in the embodiments of the present application are as follows:

in one aspect of the embodiments of the present application, a method for improving lithography precision is provided, where the method includes:

obtaining a photoetching pattern of a photoetching mask;

manufacturing a standard pattern on the standard sheet by laser cutting according to the photoetching pattern;

the standard pattern on the standard wafer and the photoetching pattern on the photoetching mask are aligned to obtain the position information of the standard wafer;

and determining the production position of the product substrate according to the position information of the standard sheet.

Optionally, before aligning the standard pattern on the standard wafer with the lithographic pattern on the lithographic mask to obtain the position information of the standard wafer, the method further includes:

obtaining an edge profile of a product substrate;

and according to the edge profile of the product substrate, carrying out laser cutting on the edge profile of the standard sheet to adjust the edge profile of the standard sheet to be coincident with the edge profile of the product substrate.

Optionally, the edge profile of the standard wafer has a lithographic identification feature when the edge profile of the standard wafer coincides with the edge profile of the production substrate.

Optionally, the lithographic identification feature is a straight edge or a concave edge.

Optionally, the manufacturing of the standard pattern on the standard sheet by laser cutting according to the lithographic pattern includes:

and forming a kerf on the standard sheet by laser cutting according to the photoetching pattern, wherein the kerf forms the standard pattern, and the depth of the kerf is smaller than the thickness of the standard sheet.

Optionally, the aligning and calibrating the standard pattern on the standard wafer and the lithography pattern on the lithography mask includes:

and aligning the standard pattern on the standard sheet with the photoetching pattern on the photoetching mask along the vertical direction so as to enable the standard pattern and the photoetching pattern to be vertically superposed.

Optionally, the standard pattern is located at the center line of the standard sheet.

Optionally, the standard sheet has a plurality of standard patterns.

Optionally, the plurality of standard patterns are distributed on the surface of the standard sheet at intervals.

In another aspect of the embodiments of the present application, an apparatus for improving lithography precision is provided, including:

the laser cutting module is used for obtaining a photoetching pattern of the photoetching mask and manufacturing a standard pattern on the standard sheet through laser cutting according to the photoetching pattern;

and the photoetching module is used for carrying out overlay calibration on the standard pattern on the standard sheet and the photoetching pattern on the photoetching mask to obtain the position information of the standard sheet, and determining the production position of the product substrate according to the position information of the standard sheet.

The beneficial effect of this application includes:

the application provides a method and a device for improving photoetching precision, wherein a laser cutting process is introduced, the high-precision characteristic of the laser cutting process is utilized to realize the manufacture of a standard pattern on a standard plate, and then the calibration of a correct placement position (production position) of a product substrate is quickly completed in a mode of alignment registration of the standard pattern on the standard plate and a photoetching pattern on a photoetching mask, so that the calibration times and the calibration time in the calibration process can be effectively reduced, and then the product substrate is conveniently placed to the calibrated production position in the actual production process, so that the high-precision alignment of the product substrate and the photoetching mask is realized, and further the photoetching precision is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a schematic flowchart illustrating a schematic flowchart of a method for improving lithography accuracy according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a standard plate according to an embodiment of the present disclosure before edge contour adjustment;

FIG. 3 is a schematic structural diagram of a standard sheet with a standard pattern after edge profile adjustment according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of another standard sheet with a standard pattern after edge profile adjustment according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating alignment of a reticle and a photolithographic mask according to an embodiment of the present application.

Icon: 110-standard piece; 111-edge profile of standard sheet; 112-standard graphics; 113-lithographic identification features; 120-a lithographic mask; 121-lithography pattern.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. It should be noted that, in case of no conflict, various features in the embodiments of the present application may be combined with each other, and the combined embodiments are still within the scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the application usually place when in use, and are used only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the devices or elements being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it is further noted that, unless expressly stated or limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Because the existing mechanical arm of the photoetching machine has X, Y shaft and angular rotation offset in the process of conveying the product substrate, the product substrate has X, Y direction offset and large angular rotation relative to the photoetching mask, and the photoetching precision is poor. The popular solution in the prior art is to use a first substrate to carry out photoetching to form a photoetching pattern on the substrate, then use a secondary element image measuring instrument to detect the shift size and the rotation angle value of a X, Y shaft, then use a first product substrate to carry out X, Y shift and the compensation of the rotation angle of the first product substrate when a second product substrate is subjected to photoetching, and then use the secondary element image measuring instrument to retest X, Y shift size and the rotation angle, wherein the photoetching compensation and detection actions are repeated for a plurality of times, so as to improve the photoetching precision.

In one aspect of the embodiments of the present application, a method for improving lithography precision is provided, in which a laser cutting process is introduced, a standard pattern on a standard sheet is manufactured by using a high precision characteristic of the laser cutting process, and then a calibration of a correct placement position (a production position) of a product substrate is completed quickly by a method of overlay alignment of the standard pattern on the standard sheet and a lithography pattern on a lithography mask, so that calibration times and calibration time in a calibration process can be reduced effectively, and then, in an actual production process, the product substrate is placed at the calibrated production position, so that the product substrate and the lithography mask are aligned with each other with high precision, thereby improving the lithography precision. Embodiments of the present application will be described below with reference to the accompanying drawings.

Referring to fig. 1, a flow chart of a method for improving lithography precision is provided, wherein the method includes:

s010: and acquiring a photoetching pattern of the photoetching mask.

First, in order to make the standard pattern 112 on the standard wafer 110 highly coincide with the lithographic pattern 121 on the lithographic mask 120, the lithographic pattern 121 on the lithographic mask 120 may be obtained first, and thus, the standard pattern may be used as a basis for laser dicing. When the lithography pattern 121 on the photomask 120 is obtained, the data interaction or data acquisition may be performed, which is not specifically limited in the present application, for example, when the data interaction is obtained, the lithography pattern 121 stored in the database may be called; when the data is acquired through data acquisition, an image sensor may acquire an image of the lithography pattern 121 on the lithography mask 120, and the lithography pattern 121 on the lithography mask 120 is obtained through image recognition.

S020: and manufacturing a standard pattern on the standard sheet by laser cutting according to the photoetching pattern.

As shown in fig. 3 or 4, after the lithographic pattern 121 is obtained, the standard pattern 112 is formed on the standard wafer 110 by the laser dicing process based on the lithographic pattern 121, so that the high-precision characteristic of the laser dicing process can be utilized to improve the formation precision of the standard pattern 112, and the standard pattern 112 can be highly overlapped with the lithographic pattern 121, thereby providing a good basis for overlay calibration.

It should be understood that the coincidence in this application may be either a perfect coincidence or an approximate coincidence, and all of them should fall within the scope of protection of this application.

S030: and aligning the standard pattern on the standard wafer with the photoetching pattern on the photoetching mask to obtain the position information of the standard wafer.

As shown in fig. 5, the standard wafer 110 is aligned with the photolithography mask 120 such that the standard pattern 112 on the standard wafer 110 is aligned with the photolithography pattern 121 on the photolithography mask 120, thereby achieving the calibration and calibration of the standard wafer 110. After the standard pattern 112 on the standard plate 110 is aligned with the lithography pattern 121 on the lithography mask 120, the positional information of the standard plate 110 can be derived.

S040: and determining the production position of the product substrate according to the position information of the standard sheet.

After the position information of the standard plate 110 is obtained through S030, the position information of the standard plate 110 may be determined as the production position of the subsequent product substrate, so that the calibration of the correct placement position (production position) of the product substrate may be quickly completed, and in the subsequent production, as long as each product substrate is placed at the position of the standard plate 110, each product substrate may be accurately aligned with the lithographic pattern 121 on the lithographic mask 120, thereby improving the lithographic accuracy.

Optionally, before the standard pattern 112 on the standard wafer 110 and the lithography pattern 121 on the lithography mask 120 are aligned to obtain the position information of the standard wafer 110 through S030, the external dimension of the standard wafer 110 may be adjusted so that the standard wafer 110 and the product substrate are identical or highly similar in external dimension, thereby avoiding that an error still exists when the product substrate is placed at the position obtained by the standard wafer 110 due to the difference in external dimension between the standard wafer 110 and the product substrate.

Because the edge profile 111 of the standard sheet needs to be trimmed and the trimming process is performed by laser cutting, before trimming, as shown in fig. 2, the standard sheet 110 with a size larger than that of the product substrate may be selected (for example, the diameter of the standard sheet 110 in fig. 1 is a, the diameter of the product substrate is b, and a is larger than b, and more specifically, the difference between a and b may be greater than or equal to 10 μm), so that the edge profile 111 of the standard sheet gradually completely coincides or approximately coincides with the edge profile of the product substrate by laser cutting during trimming, thereby obtaining the standard sheet 110 shown in fig. 3 or fig. 4. When the edge profile 111 of the standard sheet is adjusted or trimmed by laser cutting, the high-precision characteristic of laser cutting can still be utilized, and the processing precision is improved.

Specifically, the method comprises the following steps: the edge profile of the product substrate is obtained firstly, and then the edge profile 111 of the standard sheet is subjected to laser cutting according to the edge profile of the product substrate, so that the edge profile 111 of the adjusted standard sheet is completely or approximately coincident with the edge profile of the product substrate, and therefore, the difference of the standard sheet 110 and the product substrate in appearance can be effectively reduced, and the position information determined by the standard sheet 110 can be suitable for the product substrate, and high-precision photoetching is realized.

Optionally, the product substrate is easy to be identified by the lithography machine, and therefore, usually has some lithography identification features 113, so when the edge profile 111 of the standard sheet is adjusted, the lithography identification features 113 can be made on the edge profile 111 of the standard sheet by a laser cutting process, in other words, when the edge profile 111 of the standard sheet is overlapped with the edge profile of the product substrate, correspondingly, as shown in fig. 3 or fig. 4, the edge profile 111 of the standard sheet should have the lithography identification features 113. Therefore, on one hand, the identification of the photoetching machine can be facilitated, and on the other hand, the angle rotation error of the standard sheet 110 can be greatly reduced by combining the photoetching identification feature 113 and the standard pattern 112 on the standard sheet 110, so that the position information calibrated by the standard sheet 110 is more accurate, and therefore, the deviation in the X, Y axial direction can be effectively reduced, the angle rotation deviation can be greatly reduced, and the photoetching precision is further improved.

Optionally, as shown in fig. 3, the lithographic identification feature 113 is a straight edge on the edge profile of the standard wafer 110; as shown in fig. 4, the lithographic identification feature 113 is a concave edge (notch) on the edge profile of the standard wafer 110. Therefore, the angle rotation error of the standard plate 110 can be greatly reduced by combining the straight edge or the concave edge with the standard pattern 112 on the standard plate 110.

It should be understood that the present application is not limited to the order of forming the standard pattern 112 and trimming the edge profile on the standard wafer 110, and for example, the standard pattern 112 may be formed first, and then the edge profile may be trimmed; or trimming the edge contour and then manufacturing the standard pattern 112; it is also possible that both are synchronized.

Optionally, when the standard pattern 112 is manufactured on the standard sheet 110 by laser cutting according to the lithography pattern 121 through S020, a cut may be formed on the standard sheet 110 by laser cutting according to the lithography pattern 121, and the cut may be one or more, and the standard pattern 112 is formed by the cut. When the standard pattern 112 is manufactured, the depth of the laser cutting kerf is smaller than the thickness of the standard sheet 110, in other words, it is ensured that the laser cutting kerf does not penetrate through the standard sheet 110, thereby ensuring the reliability and stability of suction when the standard sheet 110 is conveyed by vacuum suction, and avoiding the influence of vacuum leakage on conveying identification caused by the perforated standard sheet 110 in the conveying process.

Optionally, when the standard pattern 112 on the standard plate 110 and the lithographic pattern 121 on the lithographic mask 120 are aligned through S030, as shown in fig. 5, the standard pattern 112 on the standard plate 110 and the lithographic pattern 121 on the lithographic mask 120 are aligned in the vertical direction, so that the standard pattern 112 and the lithographic pattern 121 coincide in the vertical direction, and thus, the product position calibrated by the standard plate 110 can be relatively accurate.

Alternatively, since the position shift region of the alignment lens of the lithography machine is usually located near the X-axis center, as shown in fig. 3 or 4, the standard pattern 112 may be located on the center line of the standard plate 110, and more specifically, may be located on the X-axis center line of the standard plate 110, thereby facilitating alignment calibration.

Alternatively, as shown in fig. 3 or 4, the standard sheet 110 may have a plurality of standard patterns 112 thereon. The plurality of standard patterns 112 may be spaced apart from each other in a line on the X-axis center line of the standard plate 110, thereby facilitating alignment calibration.

In another aspect of the embodiments of the present application, an apparatus for improving lithography precision is provided, including:

the laser cutting module is configured to obtain the lithography pattern 121 of the lithography mask 120, and produce the standard pattern 112 on the standard sheet 110 by laser cutting according to the lithography pattern 121, specifically: firstly, in order to enable the standard pattern 112 on the standard wafer 110 to be highly overlapped with the lithographic pattern 121 on the lithographic mask 120, the lithographic pattern 121 on the lithographic mask 120 may be obtained first, and then the standard pattern 112 is manufactured on the standard wafer 110 through a laser cutting process based on the lithographic pattern 121, so that the manufacturing accuracy of the standard pattern 112 can be improved by utilizing the high-accuracy characteristic of the laser cutting process, the standard pattern 112 can be highly overlapped with the lithographic pattern 121, and a good basis is provided during overlay calibration.

The lithography module is used for performing overlay calibration on the standard pattern 112 on the standard wafer 110 and the lithography pattern 121 on the lithography mask 120 to obtain the position information of the standard wafer 110, and determining the production position of the product substrate according to the position information of the standard wafer 110, specifically: the standard wafer 110 is aligned with the photolithography mask 120 such that the standard pattern 112 on the standard wafer 110 is aligned with the photolithography pattern 121 on the photolithography mask 120, thereby achieving calibration and calibration of the standard wafer 110. After the standard pattern 112 on the standard plate 110 is aligned with the lithography pattern 121 on the lithography mask 120, the positional information of the standard plate 110 can be derived. The position information of the standard sheet 110 can be determined as the production position of the subsequent product substrate, so that the calibration of the correct placement position (production position) of the product substrate can be completed quickly, and in the subsequent production, as long as each product substrate is placed at the position of the standard sheet 110, each product substrate can be accurately aligned with the photoetching pattern 121 on the photoetching mask 120, so that the photoetching precision is improved.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. A method of improving lithographic accuracy, the method comprising:

obtaining a photoetching pattern of a photoetching mask;

manufacturing a standard pattern on a standard sheet by laser cutting according to the photoetching pattern;

carrying out alignment calibration on the standard pattern on the standard wafer and the photoetching pattern on the photoetching mask to obtain the position information of the standard wafer;

and determining the production position of the product substrate according to the position information of the standard sheet.

2. The method for improving lithography accuracy as claimed in claim 1, wherein before said aligning a standard pattern on said standard wafer with a lithography pattern on said lithography mask to obtain position information of said standard wafer, said method further comprises:

acquiring an edge profile of the product substrate;

and according to the edge profile of the product substrate, carrying out laser cutting on the edge profile of the standard sheet so as to adjust the edge profile of the standard sheet to be coincident with the edge profile of the product substrate.

3. The method of improving lithography accuracy of claim 2, wherein said edge profile of said standard wafer has lithography identification features when said edge profile of said standard wafer coincides with said edge profile of said product substrate.

4. A method of improving lithographic accuracy according to claim 3, wherein the lithographic identification feature is a straight edge or a concave edge.

5. The method for improving the lithography precision as claimed in any one of claims 1 to 4, wherein said making a standard pattern on a standard sheet by laser cutting according to said lithography pattern comprises:

and forming a kerf on the standard sheet by laser cutting according to the photoetching pattern, wherein the kerf forms the standard sheet, and the depth of the kerf is smaller than the thickness of the standard sheet.

6. The method for improving the lithography precision as claimed in any one of claims 1 to 4, wherein the alignment of the standard pattern on the standard wafer with the lithography pattern on the lithography mask comprises:

and aligning the standard pattern on the standard sheet with the photoetching pattern on the photoetching mask along the vertical direction so as to enable the standard pattern to be vertically superposed with the photoetching pattern.

7. A method for improving lithographic accuracy according to any of claims 1 to 4, wherein said standard pattern is located at a center line of said standard wafer.

8. A method for improving accuracy of lithography according to any one of claims 1 through 4, wherein said standard sheet has a plurality of said standard patterns thereon.

9. The method for improving lithography accuracy of claim 8, wherein a plurality of said standard patterns are spaced apart on a surface of said standard plate.

10. An apparatus for improving lithography accuracy, comprising:

the laser cutting module is used for obtaining a photoetching pattern of a photoetching mask and manufacturing a standard pattern on a standard sheet through laser cutting according to the photoetching pattern;

and the photoetching module is used for carrying out overlay calibration on the standard pattern on the standard sheet and the photoetching pattern on the photoetching mask to obtain the position information of the standard sheet, and determining the production position of the product substrate according to the position information of the standard sheet.

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