Method for Forming a Circuit Board Via Structure for High Speed Signaling
AssigneeMicron Technology, Inc.
InventorsShiyou Zhao, Houfei Chen, Hao Wang
Life of this patent
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Abstract
One embodiment of the invention comprises an improved method for making a via structure for use in a printed circuit board (PCB). The via allows for the passage of a signal from one signal plane to another in the PCB, and in so doing transgresses the power and ground planes between the signal plane. To minimize EM disturbance between the power and ground planes, signal loss due to signal return current, and via-to-via coupling, the via is shielded within two concentric cylinders, each coupled to one of the power and ground planes.
Claims15
A method for forming a via, comprising:
- forming a first shield coupled to either a power plane or a ground plane on a first side of a circuit board, wherein forming the first shield comprises:
- forming a first hole in the first side of the circuit board, and
- positioning a first conductor on vertical edges of the first hole and in contact with the plane on the first side;
- forming a second shield within the first shield coupled to the other of the power plane or the ground plane on a second side of the circuit board, wherein forming the second shield comprises:
- forming a second hole in the second side of the circuit board, and
- positioning a second conductor on vertical edges of the second hole and in contact with the plane on the second side;
- and
- forming a via within the first and second shields.
A method for forming a via, comprising:
- forming a second conductive cylinder within a first conductive cylinder in a circuit board, wherein the first conductive cylinder is coupled to a first conductive layer in the circuit board, and wherein the second conductive cylinder is coupled to a second conductive layer in the circuit board;
- forming a first dielectric layer on the first conductive layer, and a second dielectric layer on the second conductive layer;
- forming a third conductive layer on the first dielectric layer, and a fourth conductive layer on the second dielectric layer;
- and
- forming a via through the second conductive cylinder, wherein the via is coupled to the third and fourth conductive layers.
Dependencies are inferred from the claim text.