A photolithography pattern alignment mark method

Abstract

A method for alignment mark of photolithography layout. It relates to semiconductor processing technology. It comprises the following steps: step 100, alignment mark design step of photolithography plate for Canon step-and-repeat photolithography machine, alignment pattern one is placed in cross street as register pattern; alignment pattern two is placed as unique mark for identification; step 200, alignment mark design step on photolithography plate for scanning photolithography machine, alignment pattern three is placed in cross street as register pattern of alignment pattern one; step 300, product flow sheet, before operation of step-and-repeat photolithography machine for front layer pattern, after etching, device groove and alignment pattern one and two are formed on wafer surface; step 400, alignment of alignment mark three with alignment mark on wafer. The present application is convenient for operator operation, realizes accurate control of product alignment offset, improves operation efficiency, increases effective utilization rate of machine table and improves product yield.

Description

Technical Field

[0001] This invention relates to semiconductor processing technology, and more particularly to a method for aligning and marking the layout of a photolithography machine. Background Technology

[0002] In discrete device manufacturing technology, lithography machines are needed to copy the desired pattern onto a wafer. Different process layers have different performance requirements for lithography machines. For cost considerations, different lithography machines are used for different layers of the product. Some companies may use a combination of scanning lithography machines and stepper lithography machines to complete different layers of lithography processes. PE exposure machines are scanning exposure machines, and the alignment marks on the photomask are designed with a symmetrical scheme. This ensures that the left and right alignment marks are in the same field of view during alignment, which facilitates alignment and control of overlay offset. Canon lithography machines, on the other hand, are stepper shot-by-shot exposure machines. The alignment marks reserved for the metal layer are not necessarily in symmetrical positions. When the previous layer of the product was processed by a Canon exposure machine, the left and right alignment marks are prone to not being in the same field of view. During operation, the position can be too large, and the stage position deviation can be large, leading to machine crashes and seriously affecting production efficiency. At the same time, the difficulty in controlling the overlay offset reduces product yield. Summary of the Invention

[0003] To address the above problems, this invention provides a method for lithography machine layout alignment marking that is efficient, simple, and improves product yield.

[0004] The technical solution of this invention is: a method for aligning and marking the layout of a photolithography machine, comprising the following steps: Step 100, the design steps for the alignment mark of the lithography plate for the Canon stepper lithography machine: place alignment pattern one in the cross-shaped block as the registration pattern; place alignment pattern two as the unique mark for identification. Step 200: Following the alignment mark design steps on the photomask of the scanning lithography machine, place alignment pattern three in the cross-shaped block as the overlay pattern for alignment pattern one. Step 300, product fabrication, using a stepper lithography machine to process the front layer pattern, after etching, device trenches and alignment patterns one and two are formed on the wafer surface; Step 400: Alignment marks on the three wafers are aligned.

[0005] Specifically, step 100 includes the following steps: Step 110: Draw an a*b layout according to the product size requirements, where a represents the number of rows of product dies in the exposure area and b represents the number of columns of product dies in the exposure area. Step 120: Set the coordinates, with the horizontal direction as the X-axis and the perpendicular direction as the y-axis. Place alignment marks (mark 1) on the cross-shaped blocks at the junctions of the dies as alignment indicators for the previous layer pattern. The number of dies between alignment marks (mark 1) and the Y-axis is denoted as c. To ensure that these marks are distributed in the Y-axis and located in the middle of the exposure area, b and c must satisfy the following relationship: When b is even, b = 2c must be satisfied; When b is odd, b+1=2c must be satisfied; Step 130: Set an alignment mark two to the right of any alignment mark one, and denot the number of rows of the die between the alignment mark and the X-axis as d; to ensure that the distribution of this mark in the X direction is located in the middle of the exposure area, a and d must satisfy the following relationship: When a is even, a = 2d; When a is odd, a+1=2d.

[0006] Specifically, step 200 includes the following steps: Step 210: The direction of the flat edge of the photomask parallel to the PE scanning lithography machine is denoted as the X direction, and the direction perpendicular to the flat edge is denoted as the Y direction. Step 220: First, draw the die distribution on the PE photomask, where the number of dies along the X direction at the flat edge is denoted as e; Step 230: To ensure that the column containing the alignment mark three is located in the middle of the exposure area, start counting from the first column of the die at the flat edge; When e is an even number, place alignment mark three in the cross-shaped block between the cores in column e / 2 and column e / 2+1; When e is odd, place alignment mark three between the die in column (e+1) / 2 and column (e+1) / 2+1.

[0007] Specifically, step 400 includes the following steps: Step 410: In the observation field on the right side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark three on the photomask to align with the alignment mark one next to the alignment mark two on the wafer. Step 420: In the observation field on the left side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark 3 on the photomask to align with the alignment mark 1 on the wafer, while ensuring that the positions of the alignment marks in the left and right fields of view are in the same observation field.

[0008] Beneficial effects of this invention: By optimizing the design of the alignment pattern on the lithography plate used in Canon stepper lithography machines, the alignment pattern can be viewed from the same field of view when cross-registering with PE scanning lithography machines. This facilitates operator operation, enables precise control of product alignment offset, improves work efficiency, increases machine utilization, and enhances product yield.

[0009] Figure caption Figure 1 This is a schematic diagram showing the alignment marks on the photomask used in a Canon lithography machine. Figure 2 This is a schematic diagram showing the alignment marks on the photomask used in a PE lithography machine. Figure 3 This is a schematic diagram of the alignment marks of a Canon lithography machine, showing the overlapping of the photomask alignment marks. Detailed Implementation

[0010] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0011] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0012] The following describes a lithography machine layout alignment marking method according to an embodiment of the present invention, with reference to Figures 1-3, including the following steps: Step 100, the design steps for the alignment mark of the lithography plate for the Canon stepper lithography machine: place alignment pattern one in the cross-shaped block as the registration pattern; place alignment pattern two as the unique mark for identification. Step 200: Following the alignment mark design steps on the photomask of the scanning lithography machine, place alignment pattern three in the cross-shaped block area as the overlay pattern for alignment pattern one. Step 300, product fabrication, using a stepper lithography machine to process the front layer pattern, after etching, device trenches and alignment patterns one and two are formed on the wafer surface; Step 400: Register the alignment marks on the three wafers.

[0013] Further specifying, step 100 includes the following steps: Step 110: According to the product size requirements, use layout design software to draw an a*b layout, where 'a' represents the number of rows of product dies in the exposure area, and 'b' represents the number of columns of product dies in the exposure area. Figure 1 As shown, a=4, b=5; Step 120: Set the coordinates, with the horizontal direction as the X-direction and the direction perpendicular to the X-direction as the y-direction. Place alignment marks (cross marks in the diagram) on the cross-shaped blocks at the junctions of the tube cores as markers for the alignment of the previous layer of graphics; such as... Figure 1 As shown, the number of columns of the die between the alignment mark and the Y-axis is denoted as c (e.g., Figure 1 As shown, along the X direction from right to left, there are 3 rows of dies to the left of the alignment mark (c=3). To ensure that the mark is distributed in the Y direction and located in the middle of the exposure area, b and c must satisfy the following relationship: When b is even, b = 2c must be satisfied; When b is odd, b+1=2c must be satisfied; Step 130: Set alignment mark two 80µm to the right of any alignment mark one, and denot the number of rows of the die between it and the X-axis as d (e.g., ...). Figure 1 As shown, along the Y direction from top to bottom, there are two rows of dies below the first alignment mark (denoted as d=2). To ensure that the mark is distributed in the X direction and located in the middle of the exposure area, a and d must satisfy the following relationship: When a is even, a = 2d; When a is odd, a+1=2d.

[0014] This mark serves as the only identifier in the field of view when using a PE lithography machine for alignment. It is necessary to perform an overlay operation between mark 1, located 80µm to the left of this mark, and mark 3 on the PE lithography machine's lithography plate.

[0015] Further specifying, step 200 includes the following steps: Step 210: The direction of the flat edge of the photomask parallel to the PE scanning lithography machine is denoted as the X direction, and the direction perpendicular to the flat edge is denoted as the Y direction. Step 220: According to the product size requirements, use layout design software to first draw the die distribution on the PE photomask, such as... Figure 2 As shown, the number of cores along the X direction at the flat edge is denoted as e (e.g., Figure 2 In the diagram, e=11). Step 230: To ensure that the column containing the alignment mark three is located in the middle of the exposure area, start counting from the first column of the die at the flat edge; When e is even, place alignment mark three in the cross-shaped block between the cores in column e / 2 and column e / 2+1 (e.g., ...). Figure 3 (as shown) When e is odd, place alignment mark three between the die in column (e+1) / 2 and column (e+1) / 2+1.

[0016] like Figure 2 As shown, place alignment mark three in the cross-shaped block between the 6th and 7th columns of the tube. To ensure that this mark can be aligned with mark one to the left of mark two, the alignment mark should be placed in the cross-shaped block between the d+na and d+na+1 (n=0,1,2,3...) rows of the tube along the Y direction. For example, mark three should be placed at the positions of rows 2 and 3, rows 6 and 7, rows 10 and 11, and rows 14 and 15. Figure 2 As shown.

[0017] Further specifying, step 400 includes the following steps: Step 410: In the observation field on the right side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark three on the photomask to align with the alignment mark one next to the alignment mark two on the wafer. Step 420: In the observation field on the left side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark 3 on the photomask to align with the alignment mark 1 on the wafer, while ensuring that the positions of the alignment marks in the left and right fields of view are in the same observation field.

[0018] Regarding the information disclosed in this case, the following points need to be clarified: (1) The accompanying drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case. Other structures can refer to the general design. (2) Where there is no conflict, the embodiments and features disclosed in this case can be combined with each other to obtain new embodiments; The above are merely specific embodiments disclosed in this case, but the scope of protection of this disclosure is not limited thereto. The scope of protection disclosed in this case shall be determined by the scope of protection of the claims.

Claims

1. A method for aligning and marking the layout of a photolithography machine, characterized in that, Includes the following steps: Step 100, the design steps for the alignment mark of the lithography plate for the Canon stepper lithography machine: place alignment pattern one in the cross-shaped block as the registration pattern; place alignment pattern two as the unique mark for identification. Step 200: Following the alignment mark design steps on the photomask of the scanning lithography machine, place alignment pattern three in the cross-shaped block as the overlay pattern for alignment pattern one. Step 300, product fabrication, using a stepper lithography machine to process the front layer pattern, after etching, device trenches and alignment patterns one and two are formed on the wafer surface; Step 400: Align the alignment marks on the three wafers with the same alignment marks; Step 100 includes the following steps: Step 110: Draw an a*b layout according to the product size requirements, where a represents the number of rows of product dies in the exposure area and b represents the number of columns of product dies in the exposure area. Step 120: Set the coordinates, with the horizontal direction as the X-axis and the perpendicular direction as the y-axis. Place alignment marks (mark 1) on the cross-shaped blocks at the junctions of the dies as alignment indicators for the previous layer pattern. The number of dies between alignment marks (mark 1) and the Y-axis is denoted as c. To ensure that these marks are distributed in the Y-axis and located in the middle of the exposure area, b and c must satisfy the following relationship: When b is even, b = 2c must be satisfied; When b is odd, b+1=2c must be satisfied; Step 130: Set an alignment mark two to the right of any alignment mark one, and denot the number of rows of the die between the alignment mark and the X-axis as d; to ensure that the distribution of this mark in the X direction is located in the middle of the exposure area, a and d must satisfy the following relationship: When a is even, a = 2d; When a is odd, a+1=2d; Step 200 includes the following steps: Step 210: The direction of the flat edge of the photomask parallel to the PE scanning lithography machine is denoted as the X direction, and the direction perpendicular to the flat edge is denoted as the Y direction. Step 220: First, draw the die distribution on the PE photomask, where the number of dies along the X direction at the flat edge is denoted as e; Step 230: To ensure that the column containing the alignment mark three is located in the middle of the exposure area, start counting from the first column of the die at the flat edge; When e is an even number, place alignment mark three in the cross-shaped block between the cores in column e / 2 and column e / 2+1; When e is odd, place alignment mark three between the die in column (e+1) / 2 and column (e+1) / 2+1.

2. The method for aligning photolithography machine layouts according to claim 1, characterized in that, Step 400 includes the following steps: Step 410: In the observation field on the right side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark three on the photomask to align with the alignment mark one next to the alignment mark two on the wafer. Step 420: In the observation field on the left side of the PE scanning lithography machine, adjust the position of the photomask and the wafer so that the PE scanning lithography machine uses the alignment mark 3 on the photomask to align with the alignment mark 1 on the wafer, while ensuring that the positions of the alignment marks in the left and right fields of view are in the same observation field.

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