Wafer exposure layout method

Abstract

To solve a problem that a part of a hexagon unit of one region does not completely match a part of a hexagon unit of an adjacent another region, and a utilization rate of a wafer reduces to cause a loss.SOLUTION: Provided is a wafer exposure layout method. First, a plurality of linear exposure paths are determined for the wafer. Each linear exposure paths includes a plurality of rectangular exposure regions arrayed along a straight line. A part of any rectangular exposure region overlaps an adjacent another rectangular exposure region. Then, a photomask of a honeycomb-state structure constituted of a plurality of positive hexagon units is prepared. The photomask is moved along each one of the plurality of linear exposure paths. In moving the photomask along the linear exposure paths, the photomask is moved along each one of the plurality of arrayed rectangular exposure regions. A side edge of the photomask which moved to a first exposure position of any rectangular exposure region matches a side edge of the photomask when it moved to a second exposure position in an adjacent another rectangular exposure region.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a wafer exposure layout method, and more particularly to a wafer exposure layout method that can improve the utilization rate of a wafer. [Background technology]

[0002] Conventional stepper exposure tools are applicable to the exposure process of large-area wafers. Stepper exposure tools use a dynamic movement method for single-field exposure. As shown in Figure 1, the stepper exposure tool first defines multiple regions Z1 to Zn on the wafer W, and then uses a photomask to expose a portion of the wafer W corresponding to the single region Z1. Once exposure of region Z1 is complete, the wafer W and the photomask are moved relative to each other, and the photomask exposes a portion of the wafer corresponding to the next single region Z2. This process is repeated until exposure of all the set regions on the wafer is complete.

[0003] Taking a wafer W having hexagonal elements as an example, as shown in Figures 1 and 2, a conventional photomask Y is designed with a rectangular structure to match the region size. Within the rectangular structure, each hexagonal unit corresponds to a hexagonal element. Because the sides of two adjacent regions (e.g., two horizontally adjacent regions Z1 and Z2, or two vertically adjacent regions Z1 and Z4) are connected to each other, alignment errors are likely to occur between the two adjacent regions when sequentially exposing multiple regions Z1 to Z using the photomask Y. Some hexagonal units in one region do not perfectly match some hexagonal units in another adjacent region (shown by the shaded area in Figure 2). As a result, hexagonal elements corresponding to some hexagonal units may not be fully exposed, reducing wafer utilization and potentially resulting in losses.

[0004] Therefore, how to design a wafer exposure layout method that can improve the aforementioned problems is a topic worth researching. Summary of the Invention

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a wafer exposure layout method that can be applied to polygonal elements and can improve wafer utilization.

[0006] The wafer exposure layout method of the present invention performs step exposure on a wafer on which a plurality of polygonal elements have been formed in advance. To achieve the above object, the wafer exposure layout method of the present invention includes the following steps: determining a plurality of parallel, equally spaced linear exposure paths on the wafer; each linear exposure path includes a plurality of rectangular exposure areas lined up along a straight line, with a portion of any one rectangular exposure area overlapping another adjacent rectangular exposure area; each rectangular exposure area covers a portion of the wafer; preparing a photomask; the photomask having a honeycomb structure composed of a plurality of regular hexagonal units, with uneven edges formed on each side of the photomask; each regular hexagonal unit corresponding to at least one of the plurality of polygonal elements; and moving the photomask relative to the wafer along each of the plurality of exposure paths. When moving the photomask along the exposure path, it moves along each of the lined up rectangular exposure areas, thereby exposing the wafer. When the photomask is moved to a first exposure position within the rectangular exposure area, each side edge of the photomask partially contacts each side edge of the rectangular exposure area, and at least one side edge of the photomask matches a side edge of the photomask when moved to a second exposure position within another adjacent rectangular exposure area.

[0007] In an embodiment of the present invention, each side of the photomask includes a plurality of protrusions and a plurality of recesses, and when the photomask is moved to a first exposure position in any one rectangular exposure area, the plurality of protrusions on at least one side of the photomask match with the plurality of recesses on the side of the photomask when moved to a second exposure position in another adjacent rectangular exposure area, and the plurality of recesses on at least one side of the photomask match with the plurality of protrusions on the side of the photomask when moved to the second exposure position in another adjacent rectangular exposure area.

[0008] In an embodiment of the present invention, a portion of the area extending inward from the short side of any rectangular exposure area in each exposure pass overlaps with a portion of the area extending inward from the short side of another laterally adjacent rectangular exposure area.

[0009] In an embodiment of the present invention, a portion of the area extending inward from the long side of any rectangular exposure area in each exposure pass overlaps with a portion of the area extending inward from the long side of another rectangular exposure area in another vertically adjacent exposure pass.

[0010] In an embodiment of the present invention, a portion of the area extending inward from the corner between the long and short sides of any rectangular exposure area in each exposure pass overlaps with a portion of the area extending inward from the corner between the long and short sides of another rectangular exposure area in another exposure pass adjacent in the diagonal direction.

[0011] In an embodiment of the present invention, when the photomask is moved within any of the rectangular exposure regions, the position of any of the regular hexagonal units corresponds to the position of at least one of the plurality of polygonal elements.

[0012] In an embodiment of the present invention, each regular hexagonal unit is composed of multiple polygonal subunits, and when the photomask is moved within any of the rectangular exposure areas, the position of any of the polygonal subunits corresponds to the position of one of the multiple polygonal elements.

[0013] In an embodiment of the present invention, each polygonal subunit is an equilateral triangle or an isosceles trapezoid.

[0014] In an embodiment of the present invention, each polygonal element is an equilateral triangle, an isosceles trapezoid, or a regular hexagon.

[0015] In an embodiment of the present invention, a plurality of regular hexagonal units form a plurality of rows of regular hexagonal unit groups, and the regular hexagonal unit groups in any row are alternately arranged with the regular hexagonal unit groups in another adjacent row, thereby forming a honeycomb structure.

[0016] The present invention further provides a photomask applicable to the aforementioned wafer exposure layout method, the photomask having a honeycomb structure composed of a plurality of regular hexagonal units, each of which has a concave-convex edge formed on each side, and each of which corresponds to at least one of the plurality of polygonal elements on the wafer. [Brief explanation of the drawings]

[0017] [Figure 1] Schematic diagram showing how a conventional stepper exposure tool performs a wafer exposure process. [Figure 2] A schematic diagram showing the exposure state of two adjacent areas when a conventional stepper exposure tool performs a wafer exposure process. [Figure 3] Flowchart of the wafer exposure layout method of the present invention [Figure 4] FIG. 1 is a schematic diagram showing a plurality of linear exposure paths determined by the wafer exposure layout method of the present invention. [Figure 5] 1 is a schematic diagram showing a photomask used in the wafer exposure layout method of the present invention; [Figure 6] FIG. 1 is a schematic diagram showing the trajectory of a photomask moving along each of a plurality of exposure paths relative to a wafer in the wafer exposure layout method of the present invention. [Figure 7] 1 is a schematic diagram showing the trajectory of a photomask within one rectangular exposure area in the wafer exposure layout method of the present invention. [Figure 8] FIG. 1 is a schematic diagram showing the trajectory of a photomask moving between two laterally adjacent rectangular exposure areas in the wafer exposure layout method of the present invention. [Figure 9] FIG. 1 is a schematic diagram showing the trajectory of a photomask moving between two vertically adjacent rectangular exposure areas in the wafer exposure layout method of the present invention. [Figure 10] FIG. 1 is a schematic diagram showing the trajectory of a photomask moving between two rectangular exposure areas adjacent in a diagonal direction in the wafer exposure layout method of the present invention. [Figure 11A]FIG. 1 is a schematic diagram showing another embodiment of a photomask used in the wafer exposure layout method of the present invention. [Figure 11B] FIG. 1 is a schematic diagram showing yet another embodiment of a photomask used in the wafer exposure layout method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Each embodiment and example is merely illustrative and not limiting, and after reading this specification, a person skilled in the art can make other embodiments and examples without departing from the scope of the present invention. The features and advantages of the embodiments of the present invention will become more apparent from the following detailed description and claims.

[0019] The terms "one" or "an" are used herein to describe units, elements, and assemblies described herein for convenience and to give a general sense of the scope of the invention. Thus, unless otherwise indicated, such descriptions are to be understood to include one or at least one, and the singular also includes the plural.

[0020] As used herein, the ordinal terms "first" and "second" are primarily used to distinguish or refer to identical or similar components or structures, and do not necessarily imply a spatial or temporal ordering of these components or structures. It should be noted that in certain situations or configurations, the ordinal terms may be used interchangeably without affecting the practice of the present invention.

[0021] As used herein, the terms "comprise," "comprise," "have," "have," or other similar terms are intended to be non-exclusive inclusions. For example, a component or structure comprising multiple elements is not limited to only the elements listed herein, but may include other elements not expressly listed but inherent to the component or structure.

[0022] The wafer exposure layout method of the present invention is primarily applied to a stepper exposure apparatus, which performs step exposure on a wafer on which a plurality of polygonal elements are pre-formed. The number of polygonal elements pre-formed on the wafer can be determined as needed. In the present invention, each polygonal element is an equilateral triangle, an isosceles trapezoid, or a regular hexagon, but the present invention is not limited thereto. The following description will be given with reference to FIGS. 3 to 5. FIG. 3 is a flowchart of the wafer exposure layout method of the present invention. FIG. 4 is a schematic diagram showing a plurality of linear exposure paths determined by the wafer exposure layout method of the present invention. FIG. 5 is a schematic diagram showing a photomask used in the wafer exposure layout method of the present invention. As shown in FIG. 3, the wafer exposure layout method of the present invention includes the following steps:

[0023] Step S1: Determine multiple linear exposure paths that are parallel to each other and equally spaced apart. Each linear exposure path includes multiple rectangular exposure areas lined up along a straight line. A portion of any rectangular exposure area overlaps with another adjacent rectangular exposure area. Each rectangular exposure area covers a portion of the wafer.

[0024] Because the total exposure area of ​​the photomask used for exposure is smaller than the entire area of ​​the wafer, when performing step exposure on the wafer, the photomask must be moved stepwise along an exposure path set relative to the wafer so that the range of movement of the photomask covers as much of the entire wafer area as possible. As shown in Figure 4, the present invention first determines multiple linear exposure paths L1-L9 for the wafer W to be exposed. These linear exposure paths L1-L9 are arranged parallel to each other and at equal intervals. In practice, the number and spacing of the multiple linear exposure paths L1-L9 will vary depending on the total area of ​​the wafer W and the total area of ​​the photomask 10.

[0025] Each linear exposure path includes multiple rectangular exposure areas. The multiple rectangular exposure areas are lined up along a straight line and aligned horizontally with respect to each other. In FIG. 4, for example, linear exposure path L1 includes multiple rectangular exposure areas A11-A12 lined up along a straight line and aligned horizontally with respect to each other. For example, linear exposure path L2 includes multiple rectangular exposure areas A21-A24 lined up along a straight line and aligned horizontally with respect to each other. The same applies below. The multiple rectangular exposure areas on different linear exposure paths are also lined up along straight lines perpendicular to the linear exposure paths and aligned vertically with respect to each other. For example, rectangular exposure areas A21-A81 are lined up along a vertical line and aligned vertically with respect to each other. In practice, the number and area of ​​the multiple rectangular exposure areas will vary depending on the overall area of ​​the wafer W and the overall area of ​​the photomask 10.

[0026] Each rectangular exposure area covers a portion of the wafer W. When the photomask 10 is moved within the target rectangular exposure area, a portion of the wafer W is exposed by the photomask 10. Each rectangular exposure area has two long sides and two short sides. In the present invention, a portion of any rectangular exposure area overlaps with another adjacent rectangular exposure area. "Adjacent" is defined as another rectangular exposure area that is located around any target rectangular exposure area and touches the target rectangular exposure area (at a point or a line). The overlapping positions of two different rectangular exposure areas (e.g., whether they are arranged along the same linear exposure path or along different linear exposure paths) may also be different. For example, two rectangular exposure areas may be horizontally adjacent, vertically adjacent, or diagonally adjacent.

[0027] In this embodiment, a portion of the area extending inward from the short side of one of the rectangular exposure areas in each exposure pass overlaps with a portion of the area extending inward from the short side of another laterally adjacent rectangular exposure area. That is, for the same exposure pass, the area inside one of the short sides of one of the rectangular exposure areas extends beyond the short side of another laterally adjacent rectangular exposure area and into that other rectangular exposure area. For example, this applies to laterally adjacent rectangular exposure areas A11 and A12 in linear exposure pass L1.

[0028] In an embodiment of the present invention, a portion of the area extending inward from the long side of one of the rectangular exposure areas in each exposure pass overlaps with a portion of the area extending inward from the long side of another rectangular exposure area in a different exposure pass adjacent in the vertical direction. In other words, for two adjacent different exposure passes, the area inside one long side of one of the rectangular exposure areas extends beyond the long side of another vertically adjacent rectangular exposure area and enters that other rectangular exposure area. For example, this applies to rectangular exposure area A11 in linear exposure pass L1 and rectangular exposure area A22 in linear exposure pass L2 adjacent thereto in the vertical direction.

[0029] In an embodiment of the present invention, a portion of the area extending inward from the corner between the long and short sides of one of the rectangular exposure areas in each exposure pass overlaps with a portion of the area extending inward from the corner between the long and short sides of another rectangular exposure area in a diagonally adjacent exposure pass. In other words, for two adjacent different exposure passes, the area inside the corner between the long and short sides of one of the rectangular exposure areas extends beyond the corner between the long and short sides of another diagonally adjacent rectangular exposure area and into that other rectangular exposure area. For example, this applies to rectangular exposure area A11 of linear exposure pass L1 and rectangular exposure area A21 of linear exposure pass L2, which is diagonally adjacent to it.

[0030] Therefore, in the multiple linear exposure paths L1 to L9, the multiple rectangular exposure areas A11 to A92 partially overlap each other and are regularly arranged along horizontal and vertical straight lines, so that the wafer W is closely covered by the multiple rectangular exposure areas A11 to A92.

[0031] Step S2: Prepare a photomask. The photomask has a honeycomb structure composed of a plurality of regular hexagonal units. Each side of the photomask has a concave / convex edge. Each regular hexagonal unit corresponds to at least one of the plurality of polygonal elements.

[0032] After determining the multiple linear exposure paths in step S1, the present invention then prepares a photomask 10 for exposing the wafer W. As shown in FIGS. 4 and 5, in this embodiment, the photomask 10 has a honeycomb structure composed of multiple regular hexagonal units 11. The shape and size of each regular hexagonal unit 11 matches the shape and size of a single polygonal element on the wafer, or the shape and size of a combination of multiple polygonal elements. The photomask 10 can completely fit within the rectangular exposure area. The photomask 10 is composed of the maximum number of multiple regular hexagonal units 11, thereby covering as much of the entire rectangular exposure area as possible.

[0033] In an embodiment of the present invention, a plurality of regular hexagonal units 11 form a plurality of rows of regular hexagonal unit groups. The regular hexagonal unit groups in each row are alternately arranged with the regular hexagonal unit groups in the adjacent rows, thereby forming a honeycomb structure. For example, as shown in FIG. 5, each row of regular hexagonal unit groups is composed of six regular hexagonal units 11 arranged vertically. Sixteen rows of regular hexagonal unit groups are alternately arranged horizontally. The formed honeycomb structure is roughly limited within the range of one designed rectangular exposure area. The number of regular hexagonal units 11 included in each row of regular hexagonal unit groups and the number of rows of the regular hexagonal unit groups are not limited to the above and can be changed according to structural design and requirements.

[0034] Therefore, on each side of the photomask 10 (i.e., four side edges on the upper, lower, left, and right sides of the photomask 10, other than the two large-area exposure surfaces, based on the perspective of FIG. 5), a concave-convex edge is formed by combining a plurality of regular hexagonal units 11. The concave-convex edge referred to here means that each side of the photomask 10 forms a puzzle-like concave-convex edge, not a straight edge.

[0035] More specifically, a plurality of protrusions 12 and a plurality of recesses 13 are formed on each side of the photomask 10. The plurality of protrusions 12 and the plurality of recesses 13 on each side are arranged in a roughly alternating regular pattern. The protrusions 12 and the recesses 13 are part of regular hexagonal units 11. Structurally, two side edges (i.e., two long edges or two short edges) of the photomask 10 have protrusions 12 and recesses 13 of the same shape and size. The shape and size of the protrusions 12 match the shape and size of the recesses 13. Two adjacent side edges (i.e., adjacent long edges and short edges that form a corner) of the photomask 10 have protrusions 12 and recesses 13 of different shapes and sizes.

[0036] Step S3: The photomask is moved along each of the multiple exposure paths relative to the wafer. When the photomask moves along the exposure path, it moves along each of the multiple rectangular exposure areas arranged side by side, thereby exposing the wafer.

[0037] After preparing the photomask 10 in step S2, in the present invention, the photomask 10 is moved sequentially along each of the multiple exposure paths relative to the wafer W, thereby exposing the wafer W. When the photomask 10 moves along the exposure path, it moves sequentially along each of the multiple rectangular exposure areas lined up on that exposure path, thereby performing step exposure.

[0038] The following description will be given with reference to FIGS. 4 and 6 to 10. FIG. 6 is a schematic diagram showing the trajectory of the photomask moving relative to the wafer along each of a plurality of exposure paths in the wafer exposure layout method of the present invention. FIG. 7 is a schematic diagram showing the trajectory of the photomask within one rectangular exposure area in the wafer exposure layout method of the present invention. FIG. 8 is a schematic diagram showing the trajectory of the photomask moving between two horizontally adjacent rectangular exposure areas in the wafer exposure layout method of the present invention. FIG. 9 is a schematic diagram showing the trajectory of the photomask moving between two vertically adjacent rectangular exposure areas in the wafer exposure layout method of the present invention. FIG. 10 is a schematic diagram showing the trajectory of the photomask moving between two diagonally adjacent rectangular exposure areas in the wafer exposure layout method of the present invention. Assume that nine linear exposure paths L1 to L9 parallel to each other are determined for the wafer W, as shown in FIGS. 4 and 6. Each linear exposure path includes a plurality of rectangular exposure areas lined up. The photomask 10 first moves from the first rectangular exposure area A11 to the second rectangular exposure area A12 along a first linear exposure path L1, then moves from the first rectangular exposure area A21 to the fourth rectangular exposure area A24 along a second linear exposure path L2 adjacent to the first linear exposure path L1, repeats the same movement from the third linear exposure path to the eighth linear exposure path, and finally moves to the second rectangular exposure area A92 along a ninth linear exposure path L9.

[0039] 6 and 7, in the present invention, when the photomask 10 is moved within any rectangular exposure area, the position of each regular hexagonal unit 11 of the photomask 10 corresponds to the position of at least one of the multiple polygonal elements. The shape and size of each regular hexagonal unit 11 matches the shape and size of one polygonal element or a combination of multiple polygonal elements on the wafer W, so that each regular hexagonal unit 11 of the photomask 10 can expose one polygonal element or multiple polygonal elements.

[0040] In the present invention, when the photomask 10 is moved into one of the rectangular exposure areas, the photomask 10 that is completely within the rectangular exposure area has the maximum number of regular hexagonal units 11, so that each side edge of the photomask 10 partially contacts each side edge of the rectangular exposure area. As shown in FIG. 7, for example, the ends of each protrusion 12 on each long side of the photomask 10 contact and overlap the long side of the rectangular exposure area. Each recess 13 on each long side of the photomask 10 is formed between the protrusion 12 and the long side of the rectangular exposure area. Similarly, the ends of each protrusion 12 on each short side of the photomask 10 contact and overlap the short side of the rectangular exposure area. Each recess 13 on each short side of the photomask 10 is formed between the protrusion 12 and the short side of the rectangular exposure area.

[0041] When the photomask 10 moves along one of the linear exposure paths to an exposure position within one of the rectangular exposure areas, at least one side edge of the photomask 10 coincides with a side edge of the photomask 10 when it moves to an exposure position within another adjacent rectangular exposure area. As shown in FIGS. 6 and 8, for example, when the photomask 10 moves along the linear exposure path L1 into rectangular exposure area A11, the photomask 10 is defined as being at a first exposure position P1. The outer contour of this first exposure position P1 corresponds to the uneven edges formed on each side edge of the photomask 10. Next, a portion of the wafer W is exposed using the photomask 10 at the first exposure position P1. After exposure at the first exposure position P1 is completed, the photomask 10 moves along the linear exposure path L1 into another laterally adjacent rectangular exposure area A12. At this time, the photomask 10 is defined as being at a second exposure position P2. The outer contour of this second exposure position also corresponds to the uneven edges formed on each side edge of the photomask 10.

[0042] In this embodiment, a portion of the rectangular exposure area A11 extending inward from the short side overlaps a portion of the rectangular exposure area A12 extending inward from the short side. The horizontal length of the portion is equal to the horizontal length of each protrusion 12 and each recess 13 formed on the short side of the photomask 10. The concave / convex edges on the short side of the photomask 10 at the first exposure position P1 match the concave / convex edges on the short side of the photomask 10 at the second exposure position P2. More specifically, when the photomask 10 is at the first exposure position P1 in the rectangular exposure area A11, the multiple protrusions 12 on the short side of the photomask 10 match the multiple recesses 13 on the short side of the photomask 10 when it is moved to the second exposure position P2 in the laterally adjacent rectangular exposure area A12. The multiple recesses 13 on the short sides of the photomask 10 at the first exposure position P1 match with the multiple protrusions 12 on the short sides of the photomask 10 when it moves to the second exposure position P2 in the laterally adjacent rectangular exposure area A12. The same applies when the photomask 10 subsequently moves between two other laterally adjacent rectangular exposure areas on the linear exposure path. Therefore, when the photomask 10 performs stepwise movement exposure along the linear exposure path, it is ensured that the two laterally adjacent rectangular exposure areas perfectly match, and exposure gaps can be avoided.

[0043] As shown in FIGS. 6 and 9, for example, assume that the photomask 10 moves into a rectangular exposure area A11 along a linear exposure path L1. The photomask 10 is defined to be at a first exposure position P1 at this time. The outer contour of this first exposure position P1 corresponds to the uneven edges formed on each side of the photomask 10. After the photomask 10 moves to the last rectangular exposure area A12 on the linear exposure path L1, the photomask 10 performs stepwise exposure along another linear exposure path L2 adjacent to the linear exposure path L1. When the photomask 10 moves into a rectangular exposure area A22 adjacent in the vertical direction along the linear exposure path L2, the photomask 10 is defined to be at a second exposure position P2 at this time. The outer contour of the second exposure position P2 similarly corresponds to the uneven edges formed on each side of the photomask 10.

[0044] In this embodiment, a portion of the rectangular exposure field A11 extending inward from the long side overlaps a portion of the rectangular exposure field A22 extending inward from the long side of another vertically adjacent linear exposure path L2. The vertical length of the portion is equal to the vertical length of each protrusion 12 and each recess 13 formed on the long side of the photomask 10. The uneven edges formed on the long side of the photomask 10 at the first exposure position P1 match the uneven edges formed on the long side of the photomask 10 when the photomask 10 is at the second exposure position P2. More specifically, when the photomask 10 is at the first exposure position P1 of the rectangular exposure field A11, the multiple protrusions 12 on the long side of the photomask 10 match the multiple recesses 13 on the long side of the photomask 10 when the photomask 10 is moved to the second exposure position P2 of the vertically adjacent rectangular exposure field A22. The multiple recesses 13 on the long sides of the photomask 10 at the first exposure position P1 match with the multiple protrusions 12 on the long sides of the photomask 10 when it moves to the second exposure position P2 of the vertically adjacent rectangular exposure area A22. The same applies when the photomask 10 subsequently moves between two other rectangular exposure areas on vertically adjacent linear exposure paths. Therefore, when the photomask 10 performs step-movement exposure along vertically adjacent linear exposure paths, it is ensured that the two vertically adjacent rectangular exposure areas perfectly match, and exposure gaps can be avoided.

[0045] As shown in FIGS. 6 and 10 , for example, when the photomask 10 moves into a rectangular exposure area A11 along a linear exposure path L1, the photomask 10 is defined as being at a first exposure position P1. The outer contour of the first exposure position P1 corresponds to the uneven edges formed on each side of the photomask 10. After the photomask 10 moves to the last rectangular exposure area A12 on the linear exposure path L1, the photomask 10 performs stepwise exposure along another linear exposure path L2 adjacent to the linear exposure path L1. When the photomask 10 moves into another rectangular exposure area A21 adjacent in the diagonal direction along the linear exposure path L2, the photomask 10 is defined as being at a second exposure position P2. The outer contour of the second exposure position P2 similarly corresponds to the uneven edges formed on each side of the photomask 10.

[0046] In this embodiment, a portion of the rectangular exposure area A11 extending inward from the corner between the long and short sides overlaps with a portion of the rectangular exposure area A21 extending inward from the corner between the long and short sides of another diagonally adjacent linear exposure path L2. The horizontal length of the portion is equal to the horizontal length of each protrusion 12 and each recess 13 formed on the short sides of the photomask 10. The vertical length of the portion is equal to the vertical length of each protrusion 12 and each recess 13 formed on the long sides of the photomask 10. The edges formed at the corners between the long and short sides of the photomask 10 at the first exposure position P1 coincide with the edges formed at the corners between the long and short sides of the photomask 10 when it is at the second exposure position P2. More specifically, when the photomask 10 is at the first exposure position P1 of the rectangular exposure area A11, the recess 13 at the corner between the long and short sides of the photomask 10 matches with a part of the protrusion 12 at the corner between the long and short sides of the photomask 10 when the photomask 10 moves to the second exposure position P2 of the diagonally adjacent rectangular exposure area A21. The same applies when the photomask 10 subsequently moves between two other rectangular exposure areas on diagonally adjacent linear exposure paths. Therefore, when the photomask 10 performs stepwise exposure along adjacent linear exposure paths, it is ensured that the diagonally adjacent rectangular exposure areas perfectly match, and exposure gaps can be avoided.

[0047] Therefore, the wafer exposure layout method of the present invention uses a photomask with a special structural design and a plurality of rectangular exposure areas aligned along a straight line and partially overlapping each other, and moves the photomask and wafer in steps along a plurality of linear exposure paths. The photomask shapes in adjacent rectangular exposure areas match each other, thereby maximizing overall wafer utilization. Compared to conventional stepper exposure systems, the wafer exposure layout method of the present invention avoids layout errors, incompletely exposed elements, and loss of wafer utilization that tend to occur when the photomask moves between adjacent rectangular exposure areas.

[0048] As shown in FIG. 5, the present invention provides a photomask 10 applicable to the aforementioned wafer exposure layout method. The photomask 10 has a honeycomb structure composed of a plurality of regular hexagonal units 11. A concave / convex edge is formed on each side of the photomask 10. Each regular hexagonal unit 11 corresponds to at least one of the plurality of polygonal elements. The plurality of regular hexagonal units 11 form a plurality of columns of regular hexagonal unit groups arranged vertically. The regular hexagonal unit groups in each column are alternately arranged with the regular hexagonal unit groups in another adjacent column, thereby forming a honeycomb structure.

[0049] The following description will be given with reference to FIGS. 11A and 11B. FIG. 11A is a schematic diagram showing another embodiment of a photomask applied to the present invention. FIG. 11B is a schematic diagram showing yet another embodiment of a photomask applied to the present invention. As shown in FIGS. 11A and 11B, in this other embodiment of the photomask of the present invention, each regular hexagonal unit is designed to be composed of multiple polygonal subunits to accommodate different shapes and sizes of multiple polygonal elements pre-formed on a wafer. The shape and size of each polygonal subunit matches the shape and size of the polygonal elements on the wafer.

[0050] For example, as shown in FIG. 11A, each regular hexagonal unit 11a of a photomask 10a is composed of two polygonal subunits 111. Each polygonal subunit 111 is an isosceles trapezoid. Each polygonal subunit 111 corresponds to one trapezoidal element. When the photomask is moved within any rectangular exposure area, the position of each polygonal subunit 111 corresponds to the position of one trapezoidal element.

[0051] For example, as shown in FIG. 11B, each regular hexagonal unit 11b of the photomask 10b is composed of six polygonal subunits 112. Each polygonal subunit 112 is an equilateral triangle. Each polygonal subunit 112 corresponds to one equilateral triangular element. When the photomask is moved within any rectangular exposure area, the position of each polygonal subunit 112 corresponds to the position of one equilateral triangular element.

[0052] The above-described embodiments are merely illustrative and are not intended to limit the embodiments or applications of the present application. Furthermore, while the above-described embodiments provide at least one illustrative example, it should be understood that numerous variations of the present invention are possible. Furthermore, the examples described herein are not intended to limit the scope, application, or configuration of the claims in any way. Rather, the above-described embodiments provide a guide for those skilled in the art to implement one or more of the embodiments. Furthermore, changes may be made in the function and arrangement of elements without departing from the scope of the claims, and the scope of the claims includes all known and foreseeable equivalents at the time of filing this patent application. [Explanation of symbols]

[0053] 10, 10a, 10b Photomask 11, 11a, 11b Regular hexagonal unit 111, 112 Polygonal subunits 12 Protrusion 13 Recess A11~A92 Rectangular exposure area L1~L9 Linear exposure path P1 First exposure position P2 Second exposure position W wafer S1~S3 steps Y Photomask Z1~Zn area

Claims

1. 1. A wafer exposure layout method for performing step exposure on a wafer on which a plurality of polygonal elements are formed in advance, comprising: determining a plurality of linear exposure paths on the wafer that are parallel to one another and equally spaced apart, each of the linear exposure paths including a plurality of rectangular exposure areas arranged along a straight line, a portion of any one of the rectangular exposure areas overlapping another adjacent rectangular exposure area, and each of the rectangular exposure areas covering a portion of the wafer; preparing a photomask, the photomask having a honeycomb structure composed of a plurality of regular hexagonal units, each side of the photomask having a concave-convex edge, any one of the regular hexagonal units corresponding to at least one of the plurality of polygonal elements; moving the photomask relative to the wafer along each of the plurality of exposure paths, and when the photomask moves along any of the exposure paths, the photomask moves along each of the plurality of aligned rectangular exposure areas, thereby exposing the wafer; when the photomask is moved to a first exposure position within any one of the rectangular exposure areas, each of the side edges of the photomask partially contacts each of the side edges of the rectangular exposure area, and at least one of the side edges of the photomask coincides with a side edge of the photomask when moved to a second exposure position within another adjacent rectangular exposure area; A wafer exposure layout method comprising the steps of:

2. each side of the photomask includes a plurality of protrusions and a plurality of recesses; when the photomask is moved to the first exposure position within any one of the rectangular exposure areas, the plurality of protrusions on at least one of the side edges of the photomask match with the plurality of recesses on the side edges of the photomask when the photomask is moved to the second exposure position within another adjacent rectangular exposure area; 2. The wafer exposure layout method of claim 1, wherein the plurality of recesses on at least one side of the photomask coincide with the plurality of protrusions on the side of the photomask when moved to the second exposure position in another adjacent rectangular exposure area.

3. 2. The wafer exposure layout method of claim 1, wherein a portion of an area extending inward from a short side of any of the rectangular exposure areas in each of the exposure paths overlaps with a portion of an area extending inward from a short side of another laterally adjacent rectangular exposure area.

4. 2. The wafer exposure layout method of claim 1, wherein a portion of an area extending inward from a long side of any of the rectangular exposure areas in each of the exposure passes overlaps with a portion of an area extending inward from a long side of another of the rectangular exposure areas in another of the exposure passes adjacent in the vertical direction.

5. 2. The wafer exposure layout method according to claim 1, wherein a portion of an area extending inward from a corner between the long and short sides of any of the rectangular exposure areas in each of the exposure passes overlaps with a portion of an area extending inward from a corner between the long and short sides of another of the rectangular exposure areas in another of the exposure passes adjacent in the diagonal direction.

6. 2. The wafer exposure layout method according to claim 1, wherein when the photomask is moved within any of the rectangular exposure areas, the position of any of the regular hexagonal units corresponds to the position of at least one of the plurality of polygonal elements.

7. Each of the regular hexagonal units is composed of a plurality of polygonal subunits, 2. The wafer exposure layout method of claim 1, wherein when the photomask is moved within any of the rectangular exposure areas, the position of any of the polygonal subunits corresponds to the position of one of the plurality of polygonal elements.

8. 8. The wafer exposure layout method of claim 7, wherein each of the polygonal subunits is an equilateral triangle or an isosceles trapezoid.

9. 2. The wafer exposure layout method of claim 1, wherein each of said polygonal elements is an equilateral triangle, an isosceles trapezoid, or a regular hexagon.

10. the plurality of regular hexagonal units form a plurality of rows of regular hexagonal unit groups, 2. The wafer exposure layout method according to claim 1, wherein the regular hexagonal unit groups in any one row are alternately arranged with the regular hexagonal unit groups in another adjacent row, thereby forming the honeycomb structure.

11. A photomask that is applied to the wafer exposure layout method according to any one of claims 1 to 10, comprising: the photomask has a honeycomb structure composed of a plurality of regular hexagonal units, The photomask has a concave-convex edge formed on each side thereof, A photomask, wherein any one of the regular hexagonal units corresponds to at least one of the plurality of polygonal elements of the wafer.

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