# US 2018/0025107 A1 · Symmetry verifications for differential signal vias of an electronic circuit design

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- Number: US 2018/0025107 A1
- Document ID: US20180025107A1
- Status: Published application
- Kind: A1
- Application number: 15/217,284
- Filed: 2016-07-22
- Published: 2018-01-25
- Earliest claimed: 2016-07-22
- Assignees: Hewlett Packard Enterprise Development LP
- Applicants: Hewlett Packard Enterprise Development LP
- Inventors: Karl J. Bois; Elene Chobanyan
- Web page: https://patentgrep.com/patent/US20180025107A1

## CPC

- G06F 30/398: Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A system may include an input engine and a symmetry verification engine. The input engine may access an electronic circuit design of an electronic design automation (EDA) tool as well as identify a particular net in the electronic circuit design. The a symmetry verification engine may identify a pair of differential signal vias in the electronic circuit design corresponding to the particular net and determine a verification area surrounding the pair of differential signal vias. The symmetry verification engine may also verify that a particular ground via within the verification area satisfies symmetry criteria with respect to the pair of differential signal vias.

## Claims

### Claim 1

A system comprising:
an input engine to:
access an electronic circuit design of an electronic design automation (EDA) tool; and
identify a particular net in the electronic circuit design; and
a symmetry verification engine to:
identify a pair of differential signal vias in the electronic circuit design corresponding to the particular net;
determine a verification area surrounding the pair of differential signal vias; and
verify that a particular ground via within the verification area satisfies symmetry criteria with respect to the pair of differential signal vias.

### Claim 2 (depends on 1)

The system of claim 1, wherein the input engine is further to access a verification radial parameter; and
wherein the symmetry verification engine is to determine the verification area as a circular area with a center point equal to a midpoint between the pair of differential signal vias and a radius equal to the verification radial parameter.

### Claim 3 (depends on 1)

The system of claim 1, wherein the symmetry verification engine is further to determine the particular ground via is positioned within the verification area when a center of the particular ground via is within the verification area.

### Claim 4 (depends on 1)

The system of claim 1, wherein the symmetry verification engine is further to realign the verification area to a local coordinate system for the verification area such that the pair of differential signal vias are positioned along a horizontal axis of the local coordinate system and a midpoint between the pair of signal vias is a center of the local coordinate system; and
wherein the symmetry verification engine is to verify that the particular ground via satisfies the symmetry criteria based on a position of the particular ground via in the local coordinate system, a position of a different ground via in the local coordinate system, or a combination of both.

### Claim 5 (depends on 4)

The system of claim 4, wherein the symmetry verification engine is to verify the symmetry criteria are satisfied when the particular ground via is positioned on a vertical axis of the local coordinate system that intersects the horizontal axis at the midpoint between the pair of differential signal vias.

### Claim 6 (depends on 4)

The system of claim 4, wherein the symmetry verification engine is to verify the symmetry criteria are satisfied when:
the different ground via has a horizontal coordinate value that is the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is the inverse of a vertical coordinate value of the particular ground via.

### Claim 7 (depends on 4)

The system of claim 4, wherein the symmetry verification engine is to verify the symmetry criteria are satisfied when:
the different ground via has a horizontal coordinate value that is the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is equal to a vertical coordinate value of the particular ground via.

### Claim 8 (depends on 4)

The system of claim 4, wherein the input engine is further to access a tolerance threshold; and
wherein the symmetry verification engine is to account for the tolerance threshold in verifying that the particular ground via satisfies the symmetry criteria.

### Claim 9 (depends on 8)

The system of claim 8, wherein the symmetry verification engine is to verify the symmetry criteria are satisfied when:
the different ground via has a horizontal coordinate value that is within the tolerance threshold from the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is within the tolerance threshold form the inverse of a vertical coordinate value of the particular ground via.

### Claim 10 (depends on 8)

The system of claim 8, wherein the symmetry verification engine is to verify the symmetry criteria are satisfied when:
the different ground via has a horizontal coordinate value that is within the tolerance threshold from the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is within the tolerance threshold from a vertical coordinate value of the particular ground via.

### Claim 11

A method comprising:
accessing an electronic circuit design of an electronic design automation (EDA) tool;
accessing symmetry verification parameters including an input list of net names for symmetry verification and a verification radial parameter; and
for each particular net specified in the list of net names:
identifying a pair of differential signal vias in the electronic circuit design corresponding to the particular net;
determining a verification area surrounding the pair of differential signal vias as a circular area with a center point equal to a midpoint between the pair of differential signal vias and a radius equal to the verification radial parameter; and
verifying that each ground via within the verification area satisfies symmetry criteria with respect to the pair of differential signal vias.

### Claim 12 (depends on 11)

The method of claim 11, wherein verifying that a particular ground via within the verification satisfies the symmetry criteria comprises:
identifying a first axis in the verification area that passes through the pair of differential signal vias;
identifying a second axis in the verification area that is perpendicular to the first axis and that intersects the first axis at a midpoint between the pair of differential signal vias; and
determining the particular ground via satisfies the symmetry criteria when the particular ground via is positioned with a threshold distance from the second axis.

### Claim 13 (depends on 12)

The method of claim 12, wherein verifying that the particular ground via satisfies the symmetry criteria further comprises:
identifying a ground linking segment that passes through the particular ground via and a different ground via in the verification area; and
determining the particular ground via satisfies the symmetry criteria when:
the ground linking segment intersects the first axis within the threshold distance from a midpoint between the pair of differential signal vias;
the ground linking segment is perpendicular to the second axis; and
a midpoint of the ground linking segment is within the threshold distance from the midpoint between the pair of differential signals.

### Claim 14 (depends on 13)

The method of claim 13, further comprising identifying the threshold distance as a user-specified tolerance threshold value.

### Claim 15 (depends on 11)

The method of claim 11, further comprising:
identifying a particular ground via in the electronic circuit design is within the verification area of a pair of differential signal vias when a center of the particular ground via is located within the verification area.

### Claim 16 (depends on 11)

The method of claim 11, further comprising:
identifying a particular ground via in the electronic circuit design is not within the verification area of a pair of differential signal vias when a center of the particular ground via is not located within the verification area.

### Claim 17 (depends on 11)

The method of claim 11, wherein verifying comprises:
realigning the verification area to a local coordinate system for the verification area such that the pair of differential signal vias are positioned along a horizontal axis of the local coordinate system and a midpoint between the pair of signal vias is a center of the local coordinate system; and
verifying that a particular ground via in the verification area satisfies the symmetry criteria based on a location of the particular ground via in the local coordinate system, a position of a different ground via in the local coordinate system, or a combination of both.

### Claim 18

A non-transitory machine-readable medium comprising instructions executable by a processing resource to:
access an electronic circuit design of an electronic design automation (EDA) tool;
access an input list of net names for symmetric verification; and
for each particular net specified in the input list of net names:
identify a pair of differential signal vias in the electronic circuit design corresponding to the particular net;
determine a verification area surrounding the pair of differential signal vias;
realign the verification area to a local coordinate system for the verification area such that and a midpoint between the pair of signal vias is a center of the local coordinate system and the pair of differential signal vias are positioned along a horizontal axis of the local coordinate system; and
verify that any ground via within the verification area satisfies symmetry criteria with respect to the pair of differential signal vias based on a position of the particular ground via in the local coordinate system, a position of a different ground via in the local coordinate system, or a combination of both.

### Claim 19 (depends on 18)

The non-transitory machine-readable medium of claim 18, wherein the instructions are executable to verify a particular ground via within the verification area satisfies the symmetry criteria when:
the particular ground via is positioned on a vertical axis of the local coordinate system that intersects the horizontal axis at the midpoint between the pair of differential signal vias;
wherein the instructions are executable to verify the particular ground via satisfies the symmetry criteria further when:
the different ground via has a horizontal coordinate value that is the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is the inverse of a vertical coordinate value of the particular ground via; and
wherein the instructions are executable to verify the particular ground via satisfies the symmetry criteria further when:
the different ground via has a horizontal coordinate value that is the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is equal to a vertical coordinate value of the particular ground via.

### Claim 20 (depends on 18)

The non-transitory machine-readable medium of claim 18, wherein the instructions are further executable to access a tolerance threshold; and
wherein the instructions are executable to verify a particular ground via within the verification area satisfies the symmetry criteria when:
a distance between the particular ground and a vertical axis of the local coordinate system that intersects the horizontal axis at the midpoint between the pair of differential signal vias is within the tolerance threshold;
wherein the instructions are executable to verify the particular ground via satisfies the symmetry criteria further when:
the different ground via has a horizontal coordinate value that is within the tolerance threshold from the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is within the tolerance threshold from the inverse of a vertical coordinate value of the particular ground via; and
wherein the instructions are executable to verify the particular ground via satisfies the symmetry criteria further when:
the different ground via has a horizontal coordinate value that is within the tolerance threshold from the inverse of a horizontal coordinate value of the particular ground via; and
the different ground via has a vertical coordinate value that is within the tolerance threshold from a vertical coordinate value of the particular ground via.