SYSTEMS AND METHODS FOR IDENTIFICATION AND ELIMINATION OF GEOMETRICAL DESIGN RULE VIOLATIONS OF A MASK LAYOUT BLOCK
20220390831 · 2022-12-08
Inventors
Cpc classification
G03F1/70
PHYSICS
G06F30/398
PHYSICS
International classification
G03F1/70
PHYSICS
G06F30/31
PHYSICS
Abstract
Computer-implemented systems and methods for eliminating geometrical design rule violations, maintaining mask layout electrical connectivity, reliability verification, and design for manufacturing structural correctness of a mask layout block are provided. Exemplary systems and methods include comparing a feature dimension in a mask layout data file with a design rule in a reference rule file and identifying a design rule violation of a mask layout block if the feature dimension does not match the design rule. Methods may further include automatically correcting the design rule violation by modifying the feature dimension so the feature dimension matches the design rule. A design rule auto-correction tool may be provided and be configured to compare a feature dimension in a mask layout data file with a design rule in a reference rule file and correct the design rule violation. Disclosed embodiments advantageously correct all design rules including dependency rules.
Claims
1. A computer-implemented method of eliminating geometrical design rule violations of a mask layout block, comprising: comparing a feature dimension in a mask layout data file with a design rule in a reference rule file; identifying a design rule violation of a mask layout block if the feature dimension does not match the design rule; and automatically correcting the design rule violation by modifying the feature dimension such that the feature dimension matches the design rule.
2. The method of claim 1 wherein identifying a design rule violation comprises determining that the feature dimension in the mask layout data file is greater or smaller than the design rule in the reference rule file.
3. The method of claim 1 wherein modifying the feature dimension such that the feature dimension matches the design rule comprises adjusting the feature dimension until the feature dimension is exactly equal to the design rule.
4. The method of claim 1 wherein automatically correcting the design rule violation in the mask layout data file comprises correcting all design rules including dependency rules.
5. The method of claim 1 wherein the design rule comprises one or more of: a Voltage-Aware design rule, a DFM-Aware design rule, or an RV-Aware design rule.
6. The method of claim 1 further comprising presenting the design rule violation graphically as one or more violation markers.
7. The method of claim 1 wherein the design rule violation is a hierarchical design rule violation in a sub-cell of the mask layout data file.
8. The method of claim 1 further comprising generating a clean mask layout data file without any design rule violations.
9. A system for maintaining mask layout electrical connectivity, reliability verification, and design for manufacturing structural correctness of a mask layout block, comprising: a design rule auto-correction tool configured to compare a feature dimension in a mask layout data file with a design rule in a reference rule file; wherein if the feature dimension does not match the design rule, the design rule auto-correction tool identifies a design rule violation and automatically corrects the design rule violation by modifying the feature dimension such that the feature dimension matches the design rule.
10. The system of claim 9 wherein the design rule auto-correction tool includes a convolutional neural network.
11. The system of claim 10 wherein the convolutional neural network performs deep learning of the mask layout data file.
12. The system of claim 11 wherein the convolutional neural network compares the feature dimension in the mask layout data file with the design rule in the reference rule file, identifies the design rule violation, and automatically corrects the design rule violation.
13. The system of claim 9 wherein the design rule auto-correction tool reduces size and increases density of features in the mask layout data file.
14. The system of claim 9 wherein the design rule auto-correction tool determines if spacing between polygons in the mask layout data file is greater than spacing in a minimum design rule and is configured to reduce the spacing between polygons until the spacing is equal to the spacing in the minimum design rule.
15. The system of claim 9 further comprising a violation browser displaying the design rule violation.
16. The system of claim 9 wherein the design rule auto-correction tool considers multiple patterning and automatically corrects all design rule violations on multiple layers of an integrated circuit.
17. A method of analyzing an integrated circuit mask layout data file and a reference rule file, comprising: reading a mask layout data file; reading a reference rule file; comparing a feature dimension in the mask layout data file with a design rule in the reference rule file; identifying a design rule violation in the mask layout data file if the feature dimension does not match the design rule; determining the coordinates of the design rule violation in the mask layout data file; and automatically correcting the design rule violation by modifying the feature dimension such that the feature dimension matches the design rule.
18. The method of claim 17 wherein modifying the feature dimension such that the feature dimension matches the design rule comprises adjusting the feature dimension until the feature dimension is greater than or equal to the design rule.
19. The method of claim 17 further comprising analyzing interconnecting layers of a plurality of mask layout blocks, the interconnecting layers including a top-level cell and one or more sub-cells.
20. The method of claim 19 wherein identifying a design rule violation in the mask layout data file comprises identifying a design rule violation in one or more of the top-level cell or the one or more sub-cells and automatically correcting the design rule violation comprises automatically correcting the design rule violation in one or more of the top-level cell or the one or more sub-cells.
21. The method of claim 17 wherein the reading, comparing, identifying, determining, and automatically correcting steps are performed incrementally on mask layout data that has changed since a previous run.
22. The method of claim 17 supporting FinFet manufacturing process rules and supporting digital, analog, analog-mixed signal design, and MEMs mask layout types.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The foregoing and other objects of the disclosure will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which:
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DETAILED DESCRIPTION
[0045] In the following paragraphs, embodiments will be described in detail by way of example with reference to the accompanying drawings, which are not drawn to scale, and the illustrated components are not necessarily drawn proportionately to one another. Throughout this description, the embodiments and examples shown should be considered as exemplars, rather than as limitations of the present disclosure.
[0046] As used herein, the “present disclosure” refers to any one of the embodiments described herein, and any equivalents. Furthermore, reference to various aspects of the disclosure throughout this document does not mean that all claimed embodiments or methods must include the referenced aspects. Reference to materials, configurations, directions, and other parameters should be considered as representative and illustrative of the capabilities of exemplary embodiments, and embodiments can operate with a wide variety of such parameters. It should be noted that the figures do not show every piece of equipment, nor the materials, configurations, and directions of the various circuits and communications systems.
[0047] Exemplary embodiments include systems and methods for automatic elimination of geometrical design rule (DRCs) violations of a mask layout block, maintaining the electrical connectivity (LVS), reliability constraints (RV) and design for manufacturing (DFM) structural correctness. Disclosed embodiments analyze an integrated circuit layout block and identify geometrical design rule violations. If a feature dimension does not match a rule deck reference rule disclosed systems and methods automatically correct the identified design rule violation in the mask layout data. The automatic correction maintains the integrated circuit mask layout electrical connectivity (LVS), reliability verification (RV) and Design for Manufacturing (DFM) correctness.
[0048] Exemplary embodiments modify, move, delete or/and re-create mask layout polygons to correct manufacturing process design rule violations. The systems and methods work on individual polygons and hierarchical assembly which includes top level block and sub-blocks. Exemplary embodiments use artificial intelligence technology in the form of convolutional neural networks (CNN) for deep learning of the IC layout structure, analysis, and automatic correction. A convolutional neural network provides the analysis in conjunction with geometrical correction methods.
[0049] Referring to
[0050] As best seen in
[0051] Disclosed methods and systems support any type of design rule. For example, Voltage-Aware DRC are supported. Voltage Aware Design Rules relate to physical distance, enclosure, or any feature dimension that is dependent on the electric potential difference between the objects (Voltage). In addition, systems and methods support DFM-Aware DRC. Design for Manufacturing aware Design Rules means physical feature dimension between objects that is dependent on DFM rules. RV-Aware DRC are also supported. Reliability Verification aware Design Rules means physical feature dimension between objects that is dependent on reliability constraints like Electromigration, Self-Heat, IR Drop and other related rules.
[0052] In the event of a design rule violation 18, it may be automatically corrected 1080 by modifying the feature dimension 12 so it matches the design rule 14. In the case where the feature dimension 12 is greater or smaller than the design rule 14, the feature dimension 12 would be modified or adjusted until it is exactly equal to the design rule 14. In exemplary embodiments, automatically correcting the design rule violation 18 comprises repositioning edges 20 of violating polygons 112 in the mask layout data file 10 until the feature dimension is equal to the necessary design rule 14. The method could have an Advise Mode, in which the tool highlights the design rule violation 18 without correcting it, and an Auto-Correction Mode 30.
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[0054] In the photomask assembly 11 shown in
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[0056] Exemplary methods include checking and correcting a variety of rule types, including but not limited to, geometrical, electrical, and manufacturing design rules to maintain the mask layout data electrical connectivity (LVS—Layout vs Schematic) correctness, Design for Manufacturing (DFM) rules, and reliability (RV—Reliability verification) correctness. After correcting all design rule violations 18, a clean mask layout data file without any design rule violations would be generated 1090. The clean mask layout data file may be generated in GDSII or GDS III (Oasis), CIF or native mask layout editor.
[0057] Turning to
[0058] A design rule violation report serves as an input for the tool 30. The tool 30 reads the design rule violation report, which could be produced by a third-party tool or be generated by the design rule auto-correction tool 30. The second input is a process design rule deck file 16, which includes a numerical description of all layers, their relations, and their design rules. This may be the reference for the automatic correction.
[0059] Another optional input for the design rule auto-correction tool 30 is an electrical current analysis data file 19, which typically is generated by electrical simulation tools and contains information on constraints 33, e.g., electrical, RV, DFM. In this node each electrical node current is defined. This data can be fed into the tool 30 to maintain the electrical characteristics of the overall circuitries. The tool 30 takes these current constraints into account to maintain the circuits' behavioral and featured characteristics. A reliability data file can be provided as another input for the tool 30. In this rule deck file there are allowable currents for polygons at risk of physical reliability like electromigration or self-heat phenomenon. The design rule auto-correction tool 30 takes this data into account in order to maintain the overall circuitries' electrical reliability and sustainability.
[0060] Based on the design rule violation report and all related rule decks reference mentioned above, the design rule auto-correction tool 30 processes the IC layout data, modifying, moving, removing, re-creating to correct design rule violations, including hierarchical types which may occur between sub cells. The system may shift sub-cells, modify their polygons, and grow or shrink their size. All these operations can be done without damaging the electrical connectivity (i.e., maintaining the wires' connections and hookups), or damaging reliability constraints (i.e., keeping wires' correct width [Compensating if needed], length, number of vias and similar), or damaging design for manufacturing constraints (DFM, i.e., distances between wires, polygons widths or any other DFM related design rule). The design rule auto-correction tool 30 also may generate an extracted layout netlist 23 and a report 25 on fixing the results. After the system 2 performs the requisite error analysis 27, or correction verification, a final clean layout review 29 is done and the correct layout is ready 31.
[0061] One of the most significant advantages of disclosed embodiments is that the automatic corrections of design rule violations 18 in the mask layout data file 10 includes correcting all design rules, including dependency rules, producing the correct layout 21. With certain advanced chips, many design rules have dependencies. Thus, the correction process itself may create additional violations because correcting a particular design rule can create new design rule violations. Advantageously, disclosed systems and methods consider and fix all design rules, including dependencies rules that need to be covered. The capability of the systems and methods to see the “global picture” of the entire chip's layout (which can be very large) and fix all design rules, including their dependencies rules, on the fly is a significant innovation.
[0062] Exemplary embodiments perform auto-correction utilizing the ripple effect, which involves massively moving/editing/shifting/etc. numerous polygons at the same time and analyzing and fixing on-the-fly the mask layout block's data. Using the ripple effect, the system analyzes the mask layout block and takes all polygons' design rules into considering and solving a giant puzzle. In exemplary embodiments, it starts to work on the left-most corner of the block, moving/shifting/editing polygons as it progresses with the layout block. It might make a preliminary decision to start at the left-most corner of a block or it may cut the block to few virtual sub-blocks and work on all of them in parallel, then assemble them together. The decision where to start the analysis may be made using a successive approximation algorithm.
[0063] The ripple effect may be visually accessible to the designer. After pressing a “FIX” button, he/she may see rapidly, on screen, many polygons quickly shifting/moving/modified as the program takes into consideration numerous design rules to be obeyed. The user allows (Via setup GUI) the system to grow the layout block in the X or Y directions or both. Sometimes, a grow is needed due to lack of space. If the user doesn't allow automatic growth in any direction the program will flag visually on screen, using markers areas that were not fixed due to the “not enough room” limitation. The ripple effect may be achieved via a recurrent neural network (RNN) 45 and convolutional neural network (CNN) 32, as discussed in more detail herein.
[0064] Referring to
[0065] The convolutional neural network 32 performs deep learning of the mask layout data file 10, analyzing for design rules, finding rules' correlations, and performing auto-correcting operations 35. By this deep learning, it acquires knowledge 37 about the required feature dimensions and design rules and develops a knowledge base 39 of this information. In exemplary embodiments, a recurrent neural network 45 is included in the system to help process knowledge inputs such as data from the mask layout data file 10.
[0066] The convolutional neural network 32 performs analysis 41 on the information. More particularly, it compares feature dimensions 12 in the mask layout data file 10 with design rules 14 in the reference rule file 16, identifies any design rule violations 18, and automatically corrects the design rule violations 18 to maintain electrical connectivity (LVS), reliability (RV) and manufacturing (DFM—Design for Manufacturing) rules correctness. The design rule analysis takes into account design rules from the design rule file 16, DFM guidelines 55, and other constraints 33. CNN 32 also analyzes certain restrictions 57 and communicates them to RNN 45 for design rule autocorrection. Optimization 59 may be performed by both the CNN 32 and the RNN 45. Ultimately, the system generates a fixed, correct mask layout 31.
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[0068] With reference to
[0069] It should be noted that a design rule typically defines the minimum or maximum or a geometrical combination allowable dimension for a feature fabricated on a specific layer. For example, an integrated circuit may include, among other layers, a polysilicon layer that forms the transistor gates, a metal layer that forms interconnects between transistors and a contact or via layer that connects the polysilicon layer to the metal layer. Each layer typically has at least one or more design rules associated with features in a mask layout file that are formed on the specific layer. The metal layer may include design rules for minimum, maximum or dependent allowable spacing between two or more adjacent metal features, minimum width of a metal feature and minimum and/or maximum length of a metal feature. The polysilicon and contact layers may include similar design rules where the minimum or maximum allowable dimensions are unique to that layer.
[0070] Thus, a microchip, especially an advanced one, is built with many hierarchies to make things faster. Typically, a designer starts with building a small block, then places it in another one, adds more circuits around it and places it into another one, and so forth. A complete layout of a full chip can have around 100 levels of hierarchy or more. Each block has to go through the same sets of design rule checks and other checks. Thus, it is extremely complicated to fix violations between hierarchies since there may be not enough space, and other considerations.
[0071] Turning now to
[0072] A hierarchical design rule violation 18 is a dimension-sized violation when two layout blocks 3a, 3b are placed near each other. The solution is a hierarchical geometrical fix. Layout blocks are made individually, cleaned for design rules, and assembled together. Even if the blocks themselves are DRC clean, i.e., design rule violations=0, just placing them together can create a situation where some polygons are too close to others, which then creates a hierarchical DRC violation. An example of such a situation is shown in
[0073] In such situations, disclosed systems and methods go into the blocks and shift polygons inside them to eliminate the violation 18. In this first auto-fix option, illustrated in
[0074] If necessary, the system also slightly shifts one or both blocks 3a, 3b away from each other to eliminate the violation 18. Such a process is very complex; as blocks grow each one can contain hundreds of millions of polygons. An example of this second auto-fix option is shown in
[0075] Thus, exemplary embodiments work on interconnecting layers, automatically correcting geometrical design rules of mask layout file including individual polygons, instances of a sub-cells and all other mask layout objects. Then the design rule violation 18 is automatically corrected in each instance of the sub-cells, possibly including the top-level cell or assembly block and the corresponding interconnect layers. Disclosed systems and methods also offer settings to enable cell or sub-cell growth in the X and/or Y direction in case there is not enough room to correct the design rule violations.
[0076] In exemplary embodiments, disclosed systems and methods work in parallel processing and may split the processing over numerous CPUs/GPSs over a network. This advantageously achieves higher processing speed. Disclosed embodiments also work incrementally, which means processing only the changed data since the previous run or last set of modifications. This feature saves a significant amount of time.
[0077] Exemplary systems and methods can be launched via a graphical user interface (GUI) 43 and background batch process. Design rule violations can be presented graphically 1060 as violation markers within the mask layout editor native environment. The system may include a violation browser to show each design rule violation, offering the option to automatically correct each one individually to the correct process design rule.
[0078] Exemplary embodiments advantageously support FinFet manufacturing process geometrical design rules, maintaining electrical, reliability and DFM rules correctness. Disclosed embodiments also support Digital, Analog, AMS (Analog-Mixed Signal Design) and MEMs mask layout types. The systems and methods can be integrated with existing mask layout, industry standard editors via scripting languages.
[0079] Thus, it is seen that systems and methods for eliminating geometrical design rule violations of a mask layout block and maintaining mask layout electrical connectivity, reliability verification, and design for manufacturing structural correctness of a mask layout block are provided. It should be understood that any of the foregoing configurations and specialized components or connections may be interchangeably used with any of the systems of the preceding embodiments. Although illustrative embodiments are described hereinabove, it will be evident to one skilled in the art that various changes and modifications may be made therein without departing from the scope of the disclosure. It is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the present disclosure.