Narrow-edge plane grating manufacturing structure and grating manufacturing method

Abstract

The invention provides a narrow-edge plane grating manufacturing structure and a grating manufacturing method. The narrow-edge plane grating manufacturing structure comprises a grating substrate, and a to-be-narrow-edge protection part is formed on the side face of the grating substrate; and a supplement block is arranged at the edge part of the part to be subjected to narrow edge protection so as to extend and enlarge the grating substrate. According to the narrow-edge plane grating manufacturing structure and the grating manufacturing method, the problem that the edge effect of a plane grating manufactured through an existing plane grating manufacturing method is high can be solved.

Description

Technical Field

[0001] The present invention relates to the field of a six-degree-of-freedom position measurement system of a plane grating interferometer of a double worktable of a photolithography machine, and more specifically, to a narrow-edge plane grating manufacturing structure and a grating manufacturing method. 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] Gratings are classified by manufacturing method into ruled gratings, holographic gratings, ion-etched gratings, etc. Among them, holographic gratings and ion-etched gratings can be made into high-precision gratings due to their advantages such as high diffraction efficiency, low stray light, and no ghost lines. They are used in high-end equipment. Holographic gratings are used in the position measurement system of the workpiece stage of the lithography machine.

[0005] In the manufacturing process of existing holographic gratings, glue needs to be applied on the surface of the substrate. During the glue application process, the glue accumulated at the edge will cause thickness changes, thus affecting the performance of the grating edge, which is called edge effect. Due to the existence of edge effect, according to the existing grating manufacturing process, after processing, the edge of 10 to 15 mm will be discarded (because the grating microstructure in this part is extremely weak and insufficient to form effective diffraction light).

[0006] However, in the plane grating position measurement system of the workpiece stage of the lithography machine, in order to achieve signal continuity during the long-stroke movement, there must be enough diffracted light at the edge of the grating, otherwise once the diffracted light is discontinuous, the plane grating position measurement system will lose the position information. Specifically, in the plane grating position measurement system of the workpiece stage of the lithography machine, the overall layout of the plane grating is as follows: Figure 1 As shown (the structure of a single plane grating is shown Figure 2 As shown in the figure, the entire grating layout consists of 8 "L"-shaped gratings (gratings 01 to gratings 04, gratings 06 to gratings 09) and a small grating (grating 05), among which gratings 01, gratings 02, gratings 06, gratings 07 and gratings 01 to gratings 04 are used as the position feedback of the exposure position in the double workpiece stage of the lithography machine, and gratings 03, gratings 04, gratings 08, gratings 09 and gratings 06 to gratings 09 are used as the position feedback of the measurement position in the double workpiece stage of the lithography machine. Figure 1 The seven dotted boxes shown in the figure (for example, the dotted box between plane grating 01 and plane grating 02, the dotted box between plane grating 02 and plane grating 03, etc.) are the switching areas between gratings. When the laser reading head of the plane grating position measurement system moves from one grating to another in this area, it is necessary to ensure that the position measurement system works normally, that is, in a continuous state. This requires that the edge part of each grating switching area needs to have an extremely narrow edge effect.

[0007] After precise calculation, the maximum failure range of the grating edge is required to be less than 1mm to ensure the normal operation of the position measurement system in the switching area, and this edge effect range is much smaller than the numerical range of 10 to 15mm of the existing grating manufacturing process. In other existing grating application scenarios, in order to avoid the influence of the edge part, it is only necessary to increase the size of the grating substrate by more than 15mm and leave a margin for the edge effect part; but for the most advanced photolithography machines in the semiconductor industry, the dimensional accuracy of the grating substrate needs to be controlled below 0.1mm, or even within 0.01mm, so the existing method of reducing the edge effect by increasing the substrate size is not applicable to the plane grating in the photolithography worktable; in addition, for other types of gratings with thinner thickness, the existing process usually uses high-energy pulsed lasers for cutting after processing the grating to obtain a grating with good edges, but due to the particularity of the grating microstructure, any tiny dust, abrasives, water vapor, grease, etc. generated during the cutting process will cause irreparable damage to the grating, so the method of making the grating first and then cutting is not applicable to the plane grating in the photolithography worktable.

[0008] In summary, for the large-aperture plane grating in the plane grating position measurement system of the lithography machine worktable, there is an urgent need for a method to significantly reduce the edge effect of the large-aperture plane grating without destroying the performance of the entire grating structure. Summary of the invention

[0009] In view of the above problems, an object of the present invention is to provide a narrow-edge planar grating manufacturing structure and a grating manufacturing method to solve the problem of strong edge effect of the planar grating manufactured by the existing planar grating manufacturing method.

[0010] The narrow-edge planar grating manufacturing structure provided by the present invention comprises a grating substrate, and a narrow-edge protection portion is formed on the side of the grating substrate; it is characterized in that:

[0011] A supplementary block is arranged at the edge of the portion to be protected by the narrow edge to extend and expand the grating substrate.

[0012] In addition, a preferred solution is that the supplementary block is fixed to the side surface of the grating substrate by means of optical adhesive.

[0013] In addition, a preferred solution is that the material of the supplementary block is the same as the material of the grating substrate.

[0014] In addition, a preferred solution is that the supplementary block has a trapezoidal structure.

[0015] In addition, a preferred solution is that the side surface of the supplementary block is a polished surface; and

[0016] The surface PV value of the supplementary block is less than 600nm

[0017] In addition, a preferred solution is that the side of the grating substrate that is in contact with the supplementary block photoresist is a polished surface; and

[0018] The surface PV value of the polished surface of the grating substrate is less than 600nm.

[0019] In addition, a preferred solution is that the polishing surface of the supplementary block and the polishing surface of the grating substrate are both non-chamfered surfaces.

[0020] In addition, a preferred solution is that at least two narrow edge protection portions are formed on the grating substrate; and

[0021] At least one supplementary block is arranged on each narrow edge protection portion.

[0022] On the other hand, the present invention further provides a method for manufacturing a narrow-edge plane grating, which uses the aforementioned narrow-edge plane grating manufacturing structure to manufacture a grating, and the narrow-edge plane grating manufacturing method comprises:

[0023] Select the grating substrate;

[0024] A supplementary block is provided on the narrow edge protection portion of the side surface of the grating substrate to extend and expand the grating substrate;

[0025] The grating substrate with the supplementary blocks is subjected to the processes of gluing, developing, exposing, etching and coating;

[0026] The supplementary blocks are removed to form a narrow-edge planar grating.

[0027] In addition, a preferred solution is that in the process of arranging the supplementary block on the narrow edge protection portion of the side surface of the grating substrate,

[0028] The supplementary block is fixed on the side of the grating substrate by means of optical glue.

[0029] Compared with the prior art, the narrow-edge plane grating manufacturing structure and grating manufacturing method according to the present invention have the following beneficial effects:

[0030] The grating substrate is extended and enlarged by adding photoresist blocks on the grating substrate, thereby greatly reducing the edge effect of the manufactured narrow-edge plane grating. The narrow-edge plane grating manufacturing method provided by the present invention can obtain a narrow-edge plane grating with a very good and consistent microstructure at the edge part. Compared with the traditional manufacturing process, the influence range of the edge effect can be reduced to less than 0.1 mm, or even to the edge effect of um level. In addition, the narrow-edge plane grating manufacturing method provided by the present invention has low process cost, simple method and easy implementation.

[0031] 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

[0032] 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:

[0033] Figure 1 This is the overall layout diagram of the plane grating in the double worktable position measurement system of the lithography machine;

[0034] Figure 2 It is a structural diagram of a single plane grating in an existing photolithography machine dual worktable position measurement system;

[0035] Figure 3 A structural diagram of a narrow-edge plane grating provided according to an embodiment of the present invention;

[0036] Figure 4 This is a partially enlarged view of a supplementary block provided according to an embodiment of the present invention.

[0037] Reference numerals: grating substrate 10 , supplementary block 11 .

[0038] The same reference numerals throughout the drawings indicate similar or corresponding features or functions. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] Before introducing the specific structure of the narrow-edge plane grating manufacturing structure provided by the present invention in detail, it is necessary to first briefly introduce the preparation process of the existing holographic grating (corresponding to the narrow-edge plane grating provided by the present invention). Specifically, in all current holographic grating manufacturing processes, a suitable grating substrate (usually a glass material) is first made, and then a series of processes such as coating, gluing, exposure, development, and etching are performed on the grating substrate to finally obtain a holographic grating.

[0042] The structure of the narrow-edge plane grating manufacturing structure provided by the present invention is described in detail below. Figure 3 The structure of the narrow-edge plane grating provided according to an embodiment of the present invention is as follows: Figure 4 FIG. 1 is a partially enlarged structure of a supplementary block 11 provided according to an embodiment of the present invention. Figure 3 and Figure 4As shown together, the narrow-edge planar grating manufacturing structure provided by the present invention is made based on a pre-selected grating substrate 10, and the narrow-edge planar grating manufacturing structure includes a pre-selected grating substrate 10, a portion to be protected by a narrow edge is formed on the side of the grating substrate 10, and a supplementary block 11 is arranged at the edge of the portion to be protected by the narrow edge; by arranging the supplementary block 11 at the edge portion of the grating substrate 10 that needs to be protected by the narrow edge, it is equivalent to temporarily expanding and extending the size of the designated area of ​​the grating substrate 10 (i.e., the portion to be protected by the narrow edge), thereby reducing the edge effect generated at the edge of the grating substrate 10 in the subsequent glue coating process.

[0043] In a preferred embodiment of the present invention, the supplementary block 11 needs to be fixed on the side of the grating substrate 10 by means of optical glue. It should be noted here that optical glue refers to a process of adsorbing two clean, smooth and consistent optical parts surfaces together with a little pressure without using an adhesive. By using this process, the supplementary block 11 is fixedly connected to the side of the grating substrate 10, which can not only ensure the connection stability, but also can avoid introducing other media, thereby ensuring the optical performance of the grating substrate 10 to a certain extent.

[0044] In addition, to ensure that the supplementary block 11 and the grating substrate 10 can be connected by the optical glue process, the supplementary block 11 and the grating substrate 10 are usually made of the same material; and the supplementary block 11 and the grating substrate 10 made of the same material can also prevent wear and interference between the two to a certain extent. Of course, in the actual production process, any other method that can fix the supplementary block 11 on the side of the grating substrate 10 to temporarily expand the size can also be used, such as gluing, fixing with screws after the substrate is inlaid with threads, etc., which are all considered as alternatives to the present invention.

[0045] In addition, to ensure that the supplementary block 11 can effectively prevent the edge of the grating substrate 10 from producing edge effects, the supplementary block 11 is usually configured as a trapezoidal structure. The supplementary block 11 with a trapezoidal structure can effectively prevent the edge of the grating substrate 10 from producing edge effects while reducing the volume of the supplementary block 11 as much as possible.

[0046] In addition, in a preferred embodiment of the present invention, the side of the supplementary block 11 (especially the side with photoresist on the grating substrate 10) can be set as a polished surface, and the side of the grating substrate 10 with photoresist on the supplementary block 11 is set as a polished surface; and the surface type PV value of the supplementary block 11 is set to <600nm, and the surface type PV value of the polished surface of the grating substrate 10 is set to <600nm. By polishing the side of the supplementary block 11 and the side of the grating substrate 10, the smoothness of the side of the supplementary block 11 and the side of the grating substrate 10 can be effectively improved, thereby ensuring that the two can be fixed by photoresist.

[0047] It should be explained that, in order to ensure the continuity between the two surfaces behind the photoresist supplementary block, the polished surface of the supplementary block 11 and the polished surface of the grating substrate 10 are not chamfered (ie, they are non-chamfered surfaces).

[0048] In addition, it should be noted that, usually, a plurality of (at least two) narrow-edge protection portions (i.e., edge portions that require narrow-edge protection) are formed on the grating substrate 10; and, in order to enhance the performance of the supplementary block 11 in suppressing the edge effect of the edge portion of the grating substrate 10, a plurality of (at least one) supplementary blocks 11 may be provided on each narrow-edge protection portion.

[0049] On the other hand, in order to further illustrate the specific use method of the narrow-side plane grating manufacturing structure provided by the present invention in the grating manufacturing process, the present invention also provides a narrow-side plane grating manufacturing method, which uses the aforementioned narrow-side plane grating manufacturing structure to manufacture the grating, and the narrow-side plane grating manufacturing method includes:

[0050] Select a suitable grating substrate 10;

[0051] During the processing of the grating substrate 10, a plurality of supplementary blocks 11 of suitable size and the same material as the grating substrate 10 are arranged on the side of the grating substrate 10 to be protected by narrow edges (the edge portion to be protected by narrow edges) by means of optical adhesive, so as to temporarily extend and expand the grating substrate 10;

[0052] After the photoresist is completed, the grating substrate 10 and the supplementary block 11 are taken as a new integral component, and the grating substrate 10 with the supplementary block 11 is subjected to all subsequent grating manufacturing process flows, including glue coating, development, exposure, etching, coating, etc. In these process flows, the photoresist will keep the supplementary block 11 firmly fixed on the side of the grating substrate 10;

[0053] After completing all subsequent grating manufacturing processes, in the final stage, all the supplementary blocks 11 of the previous photoresist are removed, and according to the above scheme provided by the present invention, a narrow-edge plane grating with a very good and consistent microstructure at the edge can be obtained.

[0054] As above Figure 3 and Figure 4 The narrow-edge plane grating manufacturing structure and the grating manufacturing method according to the present invention are described in an exemplary manner. However, those skilled in the art should understand that various improvements can be made to the narrow-edge plane grating manufacturing 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 narrow-edge planar grating manufacturing structure, characterized in that: The invention comprises a grating substrate, and a narrow edge protection portion is formed on the side of the grating substrate; the invention is characterized in that: A supplementary block is arranged at the edge of the portion to be protected by the narrow edge to extend and expand the grating substrate.

2. The narrow-edge plane grating manufacturing structure according to claim 1, characterized in that: The supplementary block is fixed on the side of the grating substrate by means of optical glue.

3. The narrow-edge plane grating manufacturing structure according to claim 1, characterized in that: The material of the supplementary block is the same as that of the grating substrate.

4. The narrow-edge plane grating manufacturing structure according to claim 1, characterized in that: The supplementary block has a trapezoidal structure.

5. The narrow-edge plane grating manufacturing structure according to claim 1, characterized in that: The side surface of the supplementary block is a polished surface; and The surface PV value of the supplementary block is less than 600nm.

6. The narrow-edge plane grating manufacturing structure according to claim 5, characterized in that: The polishing surface of the supplementary block and the polishing surface of the grating substrate are both non-chamfered surfaces.

7. The narrow-edge plane grating manufacturing structure according to any one of claims 1 to 6, characterized in that: At least two narrow edge protection portions are formed on the grating substrate; and At least one supplementary block is arranged on each narrow edge protection portion.

8. A method for manufacturing a narrow-edge plane grating, characterized in that: Grating manufacturing is performed using the narrow-edge plane grating manufacturing structure as described in any one of claims 1 to 7, and the narrow-edge plane grating manufacturing method comprises: Select the grating substrate; A supplementary block is provided on the narrow edge protection portion of the side surface of the grating substrate to extend and expand the grating substrate; The grating substrate with the supplementary blocks is subjected to the processes of gluing, developing, exposing, etching and coating; The supplementary blocks are removed to form a narrow-edge planar grating.

9. The method for manufacturing a narrow-edge plane grating according to claim 8, characterized in that: In the process of setting the supplementary block on the narrow edge protection portion of the side surface of the grating substrate, The supplementary block is fixed on the side of the grating substrate by means of optical glue.

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