Plane grating splicing structure and preparation method thereof

Abstract

The invention provides a plane grating splicing structure and a preparation method thereof, the plane grating splicing structure comprises at least two plane grating modules with a preset structure, and all the plane grating modules are spliced together to form a plane grating with the preset structure; moreover, each plane grating module at least comprises two small gratings, and the small gratings belonging to the same group are spliced together to form the plane grating module with a preset structure. According to the plane grating splicing structure and the grating manufacturing method, the problems that a plane grating manufactured through an existing plane grating manufacturing method is large in manufacturing difficulty, high in equipment cost and prone to damage can be solved.

Description

Technical Field

[0001] The present invention relates to the field of plane grating preparation of a double worktable of a photolithography machine, and more specifically, to a plane grating splicing structure and a preparation method thereof. Background Art

[0002] Diffraction gratings are periodic structures with dispersion, beam splitting, polarization modulation and phase matching functions in the field of optics. They have important applications in many aspects of scientific research and engineering development. Their application range has expanded from simple spectral analysis to many fields such as metrology, quantum optics, information processing and inertial confinement laser fusion. For example, in the high-power chirped pulse amplification system of inertial confinement laser fusion, the dispersion function of the grating is used to compress the already broadened and amplified pulse laser; in the spectral analysis of large-aperture astronomical telescopes, it is used to improve the system resolution, light collection and signal-to-noise ratio; in the core equipment lithography machine in the semiconductor field, it constitutes a position measurement system to feedback the position measurement information of the workpiece stage or mask stage.

[0003] The photolithography machine is the core equipment for producing semiconductor chips. During the semiconductor chip manufacturing process, the positioning accuracy of the mask stage and workpiece stage of the photolithography machine directly affects the line width of semiconductor chip processing. The plane grating is the core component in the displacement measurement system of the photolithography machine. Its manufacturing accuracy directly determines the movement accuracy and positioning accuracy of the workpiece stage and mask stage, which greatly affects the line width of the semiconductor chip.

[0004] The following are the planar grating layouts currently used in lithography machines:

[0005] Use a "U"-shaped plane grating layout (such as Figure 1 The advantages of this solution are very obvious: the entire exposure or measurement grating is manufactured in a one-time process, which is a complete whole with very good consistency, but the disadvantages are also very obvious: first, large-sized gratings are a great challenge for the manufacture of grating substrates. The larger the aperture of the brittle material, the greater the risk of damage during the processing; secondly, due to the large aperture, extremely high requirements are placed on the manufacturability, stability, reliability, etc. of the entire manufacturing process of the grating; finally, for such a large-sized grating, after the manufacturing is completed, the later testing, storage, packaging, transportation, assembly and other links can be realized, but each process step is very complicated, resulting in a sharp increase in overall cost and risk.

[0006] Use a "C" shaped flat grating layout (such as Figure 2 As shown in the figure, this solution not only appropriately retains the above advantages, but also greatly optimizes the shortcomings of the above solutions from the perspective of optimizing the grating manufacturing process and reducing risks. However, it still has quite high requirements for the manufacturing, testing, and assembly of the grating.

[0007] Use an "L" shaped planar grating layout (such as Figure 3 As shown in the figure, this scheme further optimizes the grating based on the "C" shape, making the manufacturing, testing, and assembly processes of the grating more subdivided, further reducing the risk and cost, but the size of the grating is still around 400mm, and the manufacturing of the substrate and the exposure of the grating still require special equipment, and the cost is still high; and the grating generally uses a thicker material as the grating substrate, which increases the difficulty of grating manufacturing.

[0008] In summary, there is an urgent need for a planar grating structure that is easy to manufacture and has low equipment cost. Summary of the invention

[0009] In view of the above problems, the purpose of the present invention is to provide a planar grating splicing structure and a preparation method thereof, so as to solve the problems that the planar gratings made by the existing planar grating production methods are difficult to produce, have high equipment costs and are easy to damage.

[0010] The plane grating splicing structure provided by the present invention comprises at least two plane grating modules with a preset structure, and all the plane grating modules are spliced ​​together to form a plane grating with a preset structure; and

[0011] Each of the planar grating modules comprises at least two small gratings, and the small gratings belonging to the same group are spliced ​​together to form a planar grating module with a preset structure.

[0012] In addition, it is preferred that the maximum size of the small grating is less than 12 inches.

[0013] In addition, a preferred solution is that the small grating is cut using a traditional dicing machine.

[0014] In addition, a preferred solution is that the small grating is cut using a high-energy pulse laser.

[0015] In addition, a preferred solution is that the plane grating formed by splicing all the plane grating modules together has a "U"-shaped, "C"-shaped, or "L"-shaped structure.

[0016] On the other hand, the present invention also provides a method for preparing the planar grating splicing structure as described above, the preparation method comprising:

[0017] Preparing a planar grating with a preset structure on a first preset substrate;

[0018] Dividing the plane grating with a preset structure into at least two plane grating modules with a preset structure;

[0019] Cutting each of the plane grating modules to cut each plane grating module into at least two small gratings;

[0020] Based on the structure of each planar grating module, all small gratings are glued together in groups on the second preset substrate;

[0021] Assemble all the spliced ​​small gratings.

[0022] In addition, a preferred solution is that the process of preparing a plane grating with a preset structure on the first preset substrate comprises:

[0023] The first preset substrate is subjected to glue coating, exposure, development, etching and film coating to prepare a planar grating with a preset structure on the preset substrate.

[0024] In addition, a preferred solution is that a 12-inch photolithography machine is used during the exposure process on the first preset substrate.

[0025] In addition, a preferred solution is that a high-energy pulse laser or a traditional dicing machine is used to cut each of the planar grating modules.

[0026] Compared with the prior art, the planar grating splicing structure and the preparation method thereof according to the present invention have the following beneficial effects:

[0027] The entire plane grating is divided into several small areas that can be processed by a photolithography machine, with high processing accuracy and low batch manufacturing cost; small gratings are used for layout, with good process compatibility; high-energy pulse lasers can be used to cut small gratings, and the grating structure at the edge is good after cutting; after using small gratings for splicing layout, if one of the gratings is accidentally damaged, the problem can be directly located to the smallest unit and then repaired or replaced, without the need to replace the entire grating, which is easy to operate and has low maintenance and repair costs; large plane gratings are divided into several small parts, and the overall risk is greatly reduced without affecting the overall performance, which is conducive to subsequent testing, assembly, storage and other processes.

[0028] In order to achieve the above and related purposes, one or more aspects of the present invention include features that will be described in detail later and are particularly pointed out in the claims. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all of these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By referring to the following description and claims in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand. In the accompanying drawings:

[0030] Figure 1This is the "U"-shaped layout diagram of the plane grating in the double worktable position measurement system of the lithography machine;

[0031] Figure 2 This is the "C"-shaped layout diagram of the plane grating in the double worktable position measurement system of the lithography machine;

[0032] Figure 3 This is the "L"-shaped layout diagram of the plane grating in the double worktable position measurement system of the lithography machine;

[0033] Figure 4 A planar grating module splicing structure with an "L"-shaped layout provided according to an embodiment of the present invention;

[0034] Figure 5 The structure of the second preset substrate for optical glue matching with the small grating provided in the embodiment of the present invention;

[0035] Figure 6 Structural layout of the read head and grating of the position measurement system.

[0036] The same reference numerals throughout the drawings indicate similar or corresponding features or functions. DETAILED DESCRIPTION

[0037] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is apparent that these embodiments may also be implemented without these specific details. In other examples, for ease of describing one or more embodiments, known structures and devices are shown in the form of block diagrams.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention; the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Before introducing the specific structure of the planar grating splicing structure provided by the present invention in detail, it should be noted that, through experiments, it has been found that the use of a photolithography machine to manufacture a small grating with a smaller structure has the advantages of high precision, short manufacturing cycle, low risk, low cost, and easy assembly; the maximum aperture that can be achieved by the existing photolithography machine is 12 inches, that is, the maximum size of the manufactured small grating needs to be less than 12 inches. The small grating made by the photolithography machine is thin, and the grating can be cut by a high-energy pulse laser, which makes it easy to achieve a good cutting edge. The small gratings can be spliced ​​to achieve a good transition between gratings; the use of small gratings for splicing layout can also achieve a lower manufacturing cost. Therefore, the present application proposes a solution of replacing the planar grating with a spliced ​​small grating.

[0040] The structure of the planar grating splicing structure provided by the present invention is described in detail below. Figure 4 The figure shows a planar grating module splicing structure according to an "L"-shaped layout provided by an embodiment of the present invention. Figure 5 The structure of the second preset substrate for optical bonding with the small grating provided in an embodiment of the present invention is shown. Figure 6 The structural layout of the read head and grating of the position measurement system is shown.

[0041] Combination Figures 4 to 6 It can be seen that the plane grating splicing structure provided by the present invention is divided into a plurality of (at least two) plane grating modules having a preset structure (set according to the structural characteristics of each part of the plane grating of the preset structure), and all of the plane grating modules are spliced ​​together to form a plane grating of the preset structure; specifically, each of the plane grating modules further includes a plurality of small gratings (at least two small gratings), and all the small gratings belonging to the same group are spliced ​​together to form a plane grating module of the preset structure, and all the plane grating modules together constitute the entire large plane grating.

[0042] It should be noted that the use of a photolithography machine to manufacture small gratings has the advantages of high precision, short manufacturing cycle, low risk, low cost, and easy assembly; since the maximum aperture that can be achieved by the current photolithography machine is 12 inches, and the maximum size of each small grating manufactured must be less than 12 inches; the thickness of the small grating is relatively thin, and the grating can be cut to form a small grating using a high-energy pulse laser or a traditional dicing machine, which makes it easy to achieve a good cutting edge, and the use of small gratings for splicing can achieve a good transition between gratings; the use of small gratings for splicing layout can also achieve lower manufacturing costs.

[0043] In addition, it should be noted that in the actual production process, the structure of the plane grating can be produced according to actual needs. For example, the plane grating formed by splicing all the plane grating modules together can be a "U"-shaped, "C"-shaped, or "L"-shaped structure.

[0044] To further illustrate the preparation process of the planar grating splicing structure provided by the present invention, the present invention also provides a method for preparing the planar grating splicing structure as described above, the preparation method comprising:

[0045] Using mature technology in the semiconductor industry to prepare a planar grating with a preset structure on a first preset substrate;

[0046] Dividing the plane grating with a preset structure into at least two plane grating modules with a preset structure;

[0047] Cutting each of the plane grating modules to cut each plane grating module into at least two small gratings;

[0048] Based on the structure of each planar grating module, all small gratings are glued together in groups on the second preset substrate;

[0049] Assemble all the spliced ​​small gratings.

[0050] In addition, a preferred solution is that the process of preparing a plane grating with a preset structure on the first preset substrate comprises:

[0051] The first preset substrate is subjected to glue coating, exposure, development, etching and film coating to prepare a planar grating with a preset structure on the preset substrate.

[0052] In addition, a preferred solution is to use a 12-inch photolithography machine (the largest aperture manufacturing level currently achievable domestically and internationally) during the exposure process on the first preset substrate.

[0053] In addition, a preferred solution is that, during the process of cutting each of the planar grating modules, a high-energy pulse laser or a conventional dicing machine is used to complete the cutting of small gratings of smaller size and more types.

[0054] The use of photolithography machines to manufacture small gratings has the advantages of high precision, short manufacturing cycle, low risk, low cost, and easy assembly. Since the maximum aperture that can be achieved by current photolithography machines is 12 inches, and the maximum size of each small grating manufactured must be less than 12 inches; the thickness of the small grating is relatively thin, and the grating can be cut to form a small grating using a high-energy pulse laser or a traditional dicing machine, which makes it easy to achieve a good cutting edge, and the use of small gratings for splicing can achieve a good transition between gratings; the use of small gratings for splicing layout can also achieve a lower manufacturing cost.

[0055] It should be noted that although the above advantages can be utilized by using a spliced ​​small grating instead of a planar grating module, the number of readers for reading the grating displacement information is generally 4 (4 exposure positions, such as Figure 6Reading head 34, reading head 35, reading head 36, reading head 37; measuring position 4, such as Figure 6 To achieve displacement measurement, at least three readers are required to be in working state at every moment of the movement. Therefore, the size of the small grating cannot be any size, and the layout method also has strict constraints.

[0056] The solution provided by the present invention, under the premise of giving full play to the advantages of low cost, high precision, short delivery time, low risk, easy assembly and the like of mature small grating technology, uses small gratings to splice and layout the plane gratings of the workpiece table to ensure that the position measurement system does not report errors when moving within the full stroke range, and the specifications and quantity of the small gratings are the least.

[0057] The following is a further introduction to the small grating splicing layout using the "L"-shaped planar grating as an example.

[0058] Specifically, in the process of splicing all the small gratings on the second preset substrate in groups based on the structure of each planar grating module, Figure 4 and Figure 5 As shown in common, small gratings 01, 02, 15, 16, 12 are optically glued on a first substrate 25 (corresponding to a plane grating module); small gratings 02, 03, 15, 17, 20 are optically glued on a second substrate 26 (corresponding to a plane grating module); small gratings 04, 05, 21, 22 are optically glued on a third substrate 27 (corresponding to a plane grating module); small gratings 05, 06, 22, 23 are optically glued on a fourth substrate 28 (corresponding to a plane grating module); small gratings 05, 07, 22, 24 are optically glued on a fifth substrate 29 (corresponding to a plane grating module); 29 (corresponding to a plane grating module); optically glue small gratings 04, 05, 21, 22 on the sixth substrate 30 (corresponding to a plane grating module); optically glue small gratings 08, 09, 18, 19, 20 on the seventh substrate 31 (corresponding to a plane grating module); optically glue small gratings 09, 10, 13, 14 on the eighth substrate 32 (corresponding to a plane grating module); optically glue small grating 11 on the ninth substrate 33 (corresponding to a plane grating module); after the optical gluing is completed, a total of 9 spliced ​​quasi-"L" gratings are obtained. Finally, assemble the 9 spliced ​​gratings according to normal assembly requirements. It should be noted that in Figure 4 In the diagram, small gratings with the same number have the same size and can be interchanged.

[0059] From the above-mentioned embodiment of the small grating splicing layout taking the plane grating with an "L"-shaped structure as an example, it can be known that the readers 34, 35, 36 and 37 read the displacement information at the exposure position, and the readers 38, 39, 40 and 41 read the displacement information at the measurement position. The grating structure provided by the present invention is used for splicing. At any moment, at least three readers are in a normal working state within the full stroke range of the exposure position and the measurement position, that is, the displacement measurement system can work normally.

[0060] It can be seen from the above specific embodiments that the planar grating splicing structure and the preparation method thereof provided by the present invention have at least the following advantages:

[0061] 1. Divide the entire plane grating into several small areas that can be processed by a photolithography machine, with high processing accuracy and low batch manufacturing cost;

[0062] 2. Use small gratings for layout, with good process compatibility: high-energy pulse laser can be used to cut small gratings, and the grating structure of the edge part is good after cutting;

[0063] 3. After using small gratings for splicing layout, if one of the gratings is accidentally damaged, the problem can be directly located to the smallest unit and then repaired or replaced without replacing the entire grating. It is easy to operate and has low maintenance costs.

[0064] 4. Divide the large plane grating into several small parts. Without affecting the overall performance, the overall risk is greatly reduced, which is conducive to subsequent testing, assembly, storage and other processes.

[0065] As above Figures 4 to 6 The planar grating splicing structure and the preparation method thereof according to the present invention are described by way of example. However, those skilled in the art should understand that various improvements can be made to the planar grating splicing structure and the grating manufacturing method proposed by the present invention without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the content of the attached claims.

Claims

1. A planar grating splicing structure, characterized in that: It comprises at least two plane grating modules with a preset structure, and all the plane grating modules are spliced ​​together to form a plane grating with a preset structure; and Each of the planar grating modules comprises at least two small gratings, and the small gratings belonging to the same group are spliced ​​together to form a planar grating module with a preset structure.

2. The planar grating splicing structure according to claim 1, characterized in that: The maximum dimension of the small grating is less than 12 inches.

3. The planar grating splicing structure according to claim 1, characterized in that: The small grating is cut by a conventional dicing machine.

4. The planar grating splicing structure according to claim 1, characterized in that: The small grating is cut by using a high energy pulse laser.

5. The planar grating splicing structure according to any one of claims 1 to 4, characterized in that: The plane grating formed by splicing all the plane grating modules together has a "U"-shaped, "C"-shaped or "L"-shaped structure.

6. A method for preparing a planar grating splicing structure according to any one of claims 1 to 5, characterized in that: The preparation method comprises: Preparing a planar grating with a preset structure on a first preset substrate; Dividing the plane grating with a preset structure into at least two plane grating modules with a preset structure; Cutting each of the plane grating modules to cut each plane grating module into at least two small gratings; Based on the structure of each planar grating module, all small grating optical glues are spliced ​​on a second preset substrate in groups; Assemble all the spliced ​​small gratings.

7. The method for preparing a planar grating splicing structure according to claim 6, characterized in that: The process of preparing a planar grating with a preset structure on the first preset substrate comprises: The first preset substrate is subjected to glue coating, exposure, development, etching and film coating to prepare a planar grating with a preset structure on the preset substrate.

8. The method for preparing a planar grating splicing structure according to claim 7, characterized in that: The exposure process on the preset substrate is completed using a 12-inch photolithography machine.

9. The planar grating splicing structure according to any one of claims 1 to 7, characterized in that: The process of cutting each of the planar grating modules is completed using a high-energy pulse laser or a traditional dicing machine.

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