Pattern splitting method for cracking odd-numbered rings of metal cutting layer

Abstract

The invention provides a graph splitting method for cracking odd-numbered rings of a metal cutting layer. The graph splitting method comprises the following steps: step 1, generating default splitting identifiers about a current graph and an adjacent graph based on a default splitting rule; 2, screening out graphs forming an odd number ring from the graphs for calibrating the default splitting identifiers, adjusting the splitting rules of the graphs forming the odd number ring, and calibrating specific splitting identifiers among the graphs violating the line end rule and the angle-to-angle rule; and step 3, dividing the adjacent graph with the specific splitting identifier or the default splitting identifier calibrated between the current graph and the adjacent graph into a first metal cutting mask, and dividing the rest adjacent graphs and the current graph into a second metal cutting mask. On the premise that the process difficulty and cost are not increased, uncontrollability, caused by rule conflicts, of the splitting structure is broken, various splitting results possibly existing in the splitting process are avoided, then the purpose of optimizing a metal cutting layer process window is achieved, and the risk of short circuit or open circuit of a metal wire is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, specifically to a method for breaking the pattern splitting of odd-numbered rings in a metal cutting layer. Background Technology

[0002] In theory, the linewidth of integrated circuits continues to decrease according to Moore's Law. However, as technology nodes continue to shrink, the corresponding exposure wavelength cannot keep up with the shrinking technology nodes, leading to the emergence of dual-firing technology. This method can also be extended to multi-firing technology, but considering cost savings and reduced process complexity, the number of mask splits is generally minimized.

[0003] The primary technique of double exposure is image splitting. In layout operations, this is equivalent to finding the adjacent images of the current image and identifying images with a distance of less than a set threshold as different colors according to the splitting rules. Different colors represent different final mask plates. Figure 1 Three splitting scenarios are shown. The left image illustrates the normal case without odd-numbered cycles, which can be split into two masks. The two images on the right show two cases containing odd-numbered cycles, neither of which can be split into two masks. This is because three adjacent patterns form an odd-numbered cycle, meaning the spacing between any two adjacent patterns is less than a set threshold. In this case, without specific splitting of the patterns, it can only be split into three masks or randomly. Different splitting results correspond to different risks of short circuits or open circuits in the metal lines. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a method for splitting the pattern of odd-numbered rings in a metal cutting layer, which solves the problem that the prior art cannot split multiple patterns into two mask plates when the spacing between two adjacent patterns is less than a set threshold.

[0005] To achieve the above and other related objectives, this application provides a method for breaking the pattern splitting of odd-numbered rings in a metal cutting layer, comprising: Step 1: Generate default splitting identifiers for the current graphic and its adjacent graphics based on the default splitting rules; Step 2: Select the graphics that form an odd number of rings from the graphics with the default splitting labels, adjust the splitting rules for the graphics that form an odd number of rings, and label the graphics that violate the line end rules and the corner-to-corner rules with specific splitting labels. Step 3: Mark the adjacent graphics with specific splitting marks or default splitting marks between the current graphic and its adjacent graphics into the first metal cutting mask, and mark the remaining adjacent graphics and the current graphic into the second metal cutting mask.

[0006] Preferably, the default splitting rules include boundary rules, line end rules, and diagonal-to-diagonal rules.

[0007] Preferably, the patterns forming an odd-numbered ring cannot be placed in the same metal cutting mask due to violations of boundary rules, line end rules, or diagonal rules.

[0008] Preferably, after adjusting the splitting rules in step two, the relative distance between the line ends of the patterns in the line end rule and the relative distance between the corners of the patterns in the corner-to-corner rule are set according to the process parameters of the photolithography process.

[0009] Preferably, after implementing step three, an OPC rule and model correction is implemented, and the process fluctuation bandwidth value obtained based on the OPC PW model is used as the evaluation criterion to predict the optimization effect of the metal cutting layer process window after the above division of the original layout.

[0010] As described above, the graphic splitting method for breaking odd-numbered loops in metal cutting layers provided in this application has the following beneficial effects: by filtering out adjacent graphics that conflict through default splitting rules, adjusting their splitting rules, and avoiding the formation of odd-numbered loops between adjacent graphics that violate the default splitting rules, the uncontrollability of the splitting structure caused by rule conflicts is broken without increasing the process difficulty and cost, and multiple splitting results that may exist during the splitting process are avoided, thereby achieving the purpose of optimizing the metal cutting layer process window and effectively reducing the risk of short circuits or open circuits in the metal lines. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of existing graphic splitting in dual graphics technology; Figure 2 The flowchart shown is a graphical decomposition method for cracking odd-numbered rings in a metal cutting layer provided in an embodiment of this application; Figure 3 The diagrams show graphic splitting based on existing graphic splitting methods and the graphic splitting method for cracking odd-numbered rings in metal cutting layers provided in the embodiments of this application. Detailed Implementation

[0013] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this invention.

[0014] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this application 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 on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0017] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0018] Please see Figure 2 The diagram illustrates a flowchart of a graphical decomposition method for cracking odd-numbered rings in a metal cutting layer, provided in an embodiment of this application.

[0019] like Figure 2 As shown, the method for breaking the odd-numbered rings of a metal cutting layer includes the following steps: Step 1: Generate default splitting identifiers for the current graphic and its adjacent graphics based on the default splitting rules; Step 2: Select the graphics that form an odd number of rings from the graphics with the default splitting labels, adjust the splitting rules for the graphics that form an odd number of rings, and label the graphics that violate the line end rules and the corner-to-corner rules with specific splitting labels. Step 3: Mark the adjacent graphics with specific splitting marks or default splitting marks between the current graphic and its adjacent graphics into the first metal cutting mask, and mark the remaining adjacent graphics and the current graphic into the second metal cutting mask.

[0020] In step one, with Figure 3 For example, the current graphic is labeled 1, and its adjacent graphics are labeled 2, 3, and 4. The default splitting rules include boundary rule (rule 1), line end rule (rule 2), and corner-to-corner rule (rule 3). The direction in which the current graphic and its adjacent graphics overlap with the metal line is the boundary side (…). Figure 3 The S in the figure, parallel to the direction of the metal wire, is the end of the wire. Figure 3 (E in the text).

[0021] like Figure 3 As shown to the left of the arrow in the upper middle image, the default split markers are applied to the following pairs of figures: Figure 1 and Figure 2 due to boundary rule violations; Figure 1 and Figure 3 due to line end rule violations; and Figure 1 and Figure 4 due to corner-to-corner rule violations. A boundary rule violation occurs when the relative distance between the sides of the figures is less than a set value. A line end rule violation occurs when the relative distance between the ends of the figures is less than a set value. A corner-to-corner rule violation occurs when the relative distance between the corners of the figures is less than a set value.

[0022] In step two, as Figure 3 As shown in the upper figure, due to the violation of the line end rule marking default split identifier between figures 2 and 4, figures 2, 3, and 4 form an odd-numbered ring, meaning they cannot be assigned to the same metal cutting mask. When dividing figures 1, 2, 3, and 4 into two metal cutting masks (A and B) based on existing figure splitting methods, there are... Figure 3 The three scenarios shown to the right of the arrow in the upper middle diagram.

[0023] Based on the simulation results of the optical critical correction effect model, the splitting rules for odd-numbered rings are adjusted as follows: Figure 3 As shown in the lower figure, the positions of graphic 3 and graphic 4 are swapped. A specific splitting mark is set between graphic 2 and graphic 3 according to the line end rule (rule 4), and a specific splitting mark is set between graphic 1 and graphic 3 according to the corner-to-corner rule (rule 5). Rule 4 and rule 5 are set according to the process parameters of the photolithography process.

[0024] In step three, such as Figure 3As shown in the lower figure, when graphic 1 is assigned to metal cutting mask A, graphic 4 is assigned to metal cutting mask B, which does not include graphic 1, because of the default label between graphic 1 and graphic 4. Graphic 3 is also assigned to metal cutting mask B, which does not include graphic 1, because of the specific label between graphic 1 and graphic 4. There is no label between graphic 2 and graphic 1 or graphic 4, and there are two possible splitting results. However, because there is a specific label between graphic 2 and the predetermined splitting result graphic 3 (assigned to metal cutting mask B, which does not include graphic 1), graphic 2 is assigned to the mask (metal cutting mask A), which does not include graphic 3.

[0025] After implementing step three, the process fluctuation bandwidth value V obtained based on OPC rules and model correction is implemented, and the optimization effect of the cutting layer process window after the original layout is divided as described above is predicted based on the evaluation criterion obtained based on the OPC PW model (based on the target process window conditions). The smaller the V value, the larger the process window.

[0026] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] In summary, this application filters out conflicting adjacent graphics using default splitting rules, adjusts these rules to prevent adjacent graphics that violate the default splitting rules from forming odd-numbered cycles, and overcomes the uncontrollability of the splitting structure caused by rule conflicts without increasing process difficulty or cost. This avoids multiple possible splitting results during the splitting process, thereby optimizing the metal cutting layer process window and effectively reducing the risk of short circuits or open circuits in the metal wires. Therefore, this application effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0028] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this application.

Claims

1. A method for decomposing odd-numbered rings in a metal cutting layer, characterized in that, The method includes: Step 1: Generate default splitting identifiers for the current graphic and its adjacent graphics based on the default splitting rules; Step 2: Select the graphics that form an odd number of rings from the graphics marked with the default splitting identifier, adjust the splitting rules for the graphics that form an odd number of rings, and mark specific splitting identifiers between graphics that violate the line end rule and the corner-to-corner rule. Step 3: The adjacent graphics marked with the specific split identifier or the default split identifier between the current graphic and its adjacent graphics are mapped into the first metal cutting mask, and the remaining adjacent graphics and the current graphic are mapped into the second metal cutting mask.

2. The method according to claim 1, characterized in that, The default splitting rules include boundary rules, line-end rules, and diagonal-to-diagonal rules.

3. The method according to claim 2, characterized in that, The shapes that form an odd-numbered ring cannot be placed in the same metal cutting mask if they violate the boundary rules, the line end rules, or the diagonal rules.

4. The method according to claim 1, characterized in that, In step two, after adjusting the splitting rules, the relative distance between the line ends of the patterns in the line-end rule and the relative distance between the corners of the patterns in the corner-to-corner rule are set according to the process parameters of the photolithography process.

5. The method according to claim 1, characterized in that, After implementing step three, an OPC rule and model correction is implemented, and the process fluctuation bandwidth value obtained based on the OPC PW model is used as the evaluation criterion to predict the optimization effect of the metal cutting layer process window after the above division of the original layout.

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