Copper bridge screening method under multi-constraint condition

Abstract

The invention discloses a copper bridge screening method under a multi-constraint condition, and the method comprises the following steps: constructing an RTree data structure for a polygon set, quickly indexing a spatial position through BBox, and searching to obtain a target polygon set; generating a fine-grained skeleton line set conforming to the polygon shape under the combined action of polygons of which the original shapes are inner boundary polygons and the expanded shapes are outer boundary polygons in the target polygon set; preliminarily calculating, screening and distinguishing an invalid fine-grained skeleton line set and an effective fine-grained skeleton line set; according to the method, the geometric meaning of a correct skeleton line is abstracted from an effective fine-grained skeleton line set, and the communication attribute and the segmentation attribute are coded in an overall and local expression mode, so that the screened effective skeleton line set meeting the communication attribute and the segmentation attribute is reserved between base copper; therefore, the minimum distance between the polygon and the adjacent polygon and the base copper after the polygon is expanded is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB manufacturing industry, and in particular to a copper bridge screening method under multiple constraint conditions. Background Art

[0002] With the rapid development of the semiconductor industry, the requirements for precision in the PCB manufacturing process are getting higher and higher. The printing precision of different PCB manufacturers is different. As a tool for auxiliary production, CAM products need to dynamically optimize the copper spacing. The change of copper spacing will inevitably lead to irreversible circuit errors. Therefore, under multiple constraints, ensuring that the copper spacing meets the minimum constraint distance can directly assist factory production. The copper spacing adjustment algorithm determines the copper bridge filling strategy. The current copper bridge filling algorithm mainly adopts the following three methods: (1) Direct adjustment method: Use spatial index to locate the polygon set where the copper spacing needs to be adjusted, adjust the copper spacing between polygons to ensure that the minimum distance is met. If it is not met, fill in valid copper bridge polygons at specific locations to avoid electrical failures. Although this method conforms to the designer's logic of adjusting copper spacing and filling copper bridges, it makes it difficult to determine the location of the copper bridge to be filled. (2) Bbox skeleton line generation algorithm: A skeleton line set is generated by using the bounding box of the polygon to be adjusted as the boundary, and then the invalid skeleton lines are discarded and the valid skeleton lines are retained through the skeleton line screening algorithm. This method improves the problem of method (1), but the position of the generated skeleton line set is chaotic, resulting in low quality of the retained skeleton lines. In addition to the obvious defects of the discarded invalid skeleton lines, which are easy to exclude, a large number of corner cases also limit the application scenarios, making it difficult to promote more general scenarios. (3) Voronoi skeleton line generation algorithm: Combining the problems existing in method (2), this method improves the quality of skeleton line generation. The characteristic of not generating redundant skeleton lines when polygons are densely distributed and not connected greatly improves the success rate of subsequent screening algorithms. However, the skeleton lines generated by this method meet the requirements in specific scenarios, but perform poorly in other scenarios and are not sufficient to be generalized to general scenarios. Summary of the invention

[0003] The main technical problem solved by the present invention is to provide a copper bridge screening method under multiple constraints, and retain the screened effective skeleton line set that meets the connectivity attribute and the segmentation attribute between the base copper to ensure the minimum distance between the polygon and the adjacent polygon and the base copper after inflation. The supplemented copper bridge position is accurate, coherent and complete, ensuring that the modified PCB does not have electrical faults, optimizing the memory occupancy rate and improving the execution speed of the algorithm.

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is: a copper bridge screening method under multiple constraints, which is applied to the copper spacing adjustment in the PCB manufacturing industry, comprising the following steps: Step 1: Spatial index: construct the RTree data structure of the polygon set, quickly index the spatial position through BBox, and find the target polygon set; Step 2: skeleton line generation: The polygons whose original shapes are inner boundary polygons and whose shapes after inflation are outer boundary polygons in the target polygon set are combined to generate a fine-grained skeleton line set that conforms to the polygon shape; Step 3: Fine-grained skeleton line preprocessing: preliminary calculation and screening to distinguish invalid fine-grained skeleton line sets and valid fine-grained skeleton line sets; Step 4: Screening of effective fine-grained skeleton lines: Abstract the geometric meaning of the correct skeleton line from the set of effective fine-grained skeleton lines, encode the connectivity attributes and segmentation attributes through overall and local expressions, and retain the screened effective skeleton line set that meets the connectivity attributes and segmentation attributes between the base coppers to ensure the minimum distance between the polygon and the adjacent polygon and the base copper after inflation.

[0005] In a preferred embodiment of the present invention, in step 4: from an overall perspective: define the valid fine-grained skeleton lines connected end to end as a complete skeleton line, and determine the connectivity attribute through the two end points of the complete skeleton line; from a local perspective: find any valid fine-grained skeleton line with segmentation attribute from the complete skeleton lines with connectivity attributes, and define the complete skeleton lines as having segmentation attributes.

[0006] In a preferred embodiment of the present invention, if both end points of the complete skeleton line are within the contour range of the base copper, it is determined that the complete skeleton line has a connectivity attribute.

[0007] In a preferred embodiment of the present invention, it also includes a judgment step of discarding complete skeleton lines that do not have connectivity attributes or segmentation attributes.

[0008] In a preferred embodiment of the present invention, step 3 also includes a step of discarding the invalid fine-grained skeleton line set identified by preliminary calculation and screening.

[0009] The beneficial effects of the present invention are as follows: the present invention points out a copper bridge screening method under multiple constraints, which retains the screened effective skeleton line set that meets the connectivity attribute and the segmentation attribute between the base coppers to ensure the minimum distance between the polygon and the adjacent polygon and the base copper after inflation, the position of the supplemented copper bridge is accurate and coherent and complete, and the modified PCB is guaranteed to have no electrical faults, optimizes the memory usage, improves the execution speed of the algorithm, optimizes the skeleton line generation algorithm and invents a skeleton line screening strategy under multiple constraints. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention: Figure 1 It is a schematic flow chart of the copper bridge screening method under multiple constraints; Figure 2 It is a flowchart of a skeleton line screening algorithm in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0011] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] See also Figure 1~Figure 2 The embodiment of the present invention provides a copper bridge screening method under multiple constraints, which is applied to copper spacing adjustment in the PCB manufacturing industry, and includes the following steps: Spatial index: Construct the RTree data structure of the polygon set, quickly index the spatial position through BBox, find the target polygon set, and the subsequent skeleton line set also uses this data structure to facilitate fast positioning; Skeleton line generation: The polygons whose original shapes are inner boundary polygons and whose shapes are outer boundary polygons after inflation in the target polygon set are used together to generate a fine-grained skeleton line set that conforms to the polygon shape. This can greatly fit the polygon shape, avoid the chaotic skeleton line positions in the existing methods, and improve the data quality of the effective skeleton lines. Fine-grained skeleton line preprocessing: preliminary calculation and screening distinguish invalid fine-grained skeleton line sets and valid fine-grained skeleton line sets, and discard the invalid fine-grained skeleton line sets distinguished by preliminary calculation and screening. The existing preprocessing logic is developed on the basic point that all skeleton lines should be discarded, while the present invention starts from the basic point of retention and only discards the invalid fine-grained skeleton line sets preliminarily detected, while the main retention actions are handed over to the subsequent valid fine-grained skeleton line screening algorithm, which effectively improves the operation efficiency of the algorithm, reduces the execution of redundant steps, and transfers the screening rights to a more powerful core logic: valid fine-grained skeleton line screening.

[0013] Effective fine-grained skeleton line screening: Abstract the geometric meaning of the correct skeleton line from the effective fine-grained skeleton line set, code the connectivity and segmentation attributes through overall and local expressions, and retain the screened effective skeleton line set that meets the connectivity and segmentation attributes between the base coppers to ensure the minimum distance between the polygon and the adjacent polygons and the base copper after inflation.

[0014] The existing screening algorithm can cope with most scenarios when the quality of the effective skeleton line is guaranteed, but it is not enough to meet the general requirements for processing Corner case, that is, the code logic at this time is a sufficient but not necessary condition. In the specific embodiment of the present invention, the meaning of the correct skeleton line is re-abstracted, and the geometric meaning of the correct skeleton line should be further analyzed, and the connectivity attribute is reflected from whether the endpoints of the skeleton lines connected from beginning to end touch the base copper, and the segmentation attribute is reflected by the existence of a skeleton line that divides two unconnected areas. Both the overall perspective and the local perspective are considered. The practical results show that the skeleton line screening algorithm of the present invention can accurately supplement the complete copper bridge in complex application scenarios, and is more robust and general than the existing algorithms.

[0015] Specifically, from an overall perspective: the effective fine-grained skeleton lines connected end to end are defined as a complete skeleton line, and the connectivity attributes are judged by the two end points of the complete skeleton line. For example, a complete skeleton line includes multiple skeleton lines. When judging, if the starting end of the first skeleton line and the ending end of the last skeleton line are within the contour range of the base copper (that is, the two endpoints touch the base copper), then the entire complete skeleton line is judged to have the connectivity attribute. From a local perspective: if any effective fine-grained skeleton line with the segmentation attribute is found in the complete skeleton line with the connectivity attribute, then the complete skeleton line is defined to have the segmentation attribute. "Segmentation" represents the whole with the local. As long as there is any effective fine-grained skeleton line with the segmentation attribute, the complete skeleton line set has the segmentation attribute. After the judgment, the complete skeleton lines that do not have the connectivity attribute and the segmentation attribute are discarded, and the screened effective skeleton line set that meets the connectivity attribute and the segmentation attribute is retained between the base copper, thereby realizing the adjustment of the copper spacing and ensuring the minimum distance between coppers.

[0016] In summary, the present invention points out a copper bridge screening method under multiple constraints, which retains the screened effective skeleton line set that meets the connectivity attribute and the segmentation attribute between the base copper to ensure the minimum distance between the polygon and the adjacent polygon and the base copper after inflation, and the position of the supplemented copper bridge is accurate, coherent and complete, ensuring that the modified PCB does not have electrical faults, optimizing the memory usage, improving the execution speed of the algorithm, optimizing the skeleton line generation algorithm and inventing a skeleton line screening strategy under multiple constraints.

[0017] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A copper bridge screening method under multiple constraints, characterized in that: The following steps are involved: Step 1: Spatial index: construct the RTree data structure of the polygon set, quickly index the spatial position through BBox, and find the target polygon set; Step 2: skeleton line generation: The polygons whose original shapes are inner boundary polygons and whose shapes are outer boundary polygons after inflation in the target polygon set are used together to generate a fine-grained skeleton line set that conforms to the polygon shape; Step 3: Fine-grained skeleton line preprocessing: preliminary screening to distinguish invalid fine-grained skeleton line sets from valid fine-grained skeleton line sets; Step 4: Screening of effective fine-grained skeleton lines: Abstract the geometric meaning of the correct skeleton line from the set of effective fine-grained skeleton lines, encode the connectivity attributes and segmentation attributes through overall and local expressions, and retain the screened effective skeleton line set that meets the connectivity attributes and segmentation attributes between the base coppers to ensure the minimum distance between the polygon and the adjacent polygon and the base copper after inflation.

2. The copper bridge screening method under multiple constraints according to claim 1, characterized in that: In step 4: from the overall perspective: define the valid fine-grained skeleton line connected end to end as a complete skeleton line, and determine the connectivity attribute through the two end points of the complete skeleton line; from the local perspective: find any valid fine-grained skeleton line with segmentation attribute from the complete skeleton line with connectivity attribute, and define the complete skeleton line with segmentation attribute.

3. The copper bridge screening method under multiple constraints according to claim 2, characterized in that: If both end points of the complete skeleton line are within the outline range of the base copper, it is determined that the complete skeleton line has a connectivity attribute.

4. The copper bridge screening method under multiple constraints according to claim 2, characterized in that: The method also includes a judgment step of discarding complete skeleton lines that do not have connectivity attributes or segmentation attributes.

5. The copper bridge screening method under multiple constraints according to claim 1, characterized in that: Step 3 also includes the step of discarding the invalid fine-grained skeleton line set identified by the preliminary screening.

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