Solder pads with concave edges for ball grid arrays

Patent metadata

Field	Value
Publication number	US-12328826-B2
Application number	US-202217571092-A
Country	US
Kind code	B2
Filing date	Jan 7, 2022
Priority date	Jan 7, 2022
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

A device is provided that includes: a substrate including dielectric material and a conductive via extending into the substrate from a surface of the substrate. The device further includes a conductive pad positioned at the surface of the substrate and offset in a plane of the surface from the conductive via, the conductive pad to receive a solder joint connection to an electronic component. The conductive pad includes a concave edge that defines a gap with a convex edge of the conductive via.

First claim

What is claimed is:

1. A device comprising:
a substrate including dielectric material;
a conductive via extending into the substrate from a surface of the substrate; and
a conductive pad positioned at the surface of the substrate and offset in a plane of the surface from the conductive via, the conductive pad to receive a solder joint connection to an electronic component;
wherein the conductive pad includes a circularly concave edge that defines a gap with a circularly convex edge of the conductive via,
wherein the circularly concave edge of the conductive pad and the circularly convex edge of the conductive via comprise respective circular segments that share a same circular center, wherein the circularly concave edge of the conductive pad and the circularly convex edge of the conductive via include complementary circular curvature that provide the gap with a constant width along an entirety of the circularly concave edge.

2. The device of claim 1 , wherein the conductive pad includes a plurality of circularly concave edges that each define a respective gap with a circularly convex edge of a respective conductive via.

3. The device of claim 2 , wherein the plurality of circularly concave edges are radially evenly spaced with respect to a center of the conductive pad.

4. The device of claim 1 , wherein the conductive pad includes a plurality of lobes and a plurality of circularly concave edges, wherein adjacent pairs of lobes are separated by one of the circularly plurality of concave edges.

5. The device of claim 1 :
wherein the conductive via is a first conductive via that is aligned with an axis perpendicular to the surface of the substrate with a first length of a conductive material;
the device further comprising a second conductive via that is aligned with the axis perpendicular to the surface of the substrate with a second length of a conductive material;
wherein the conductive material has a coefficient of thermal expansion that is different than a coefficient of thermal expansion of the dielectric material of the substrate;
wherein the first length of the conductive material is greater than the second length of the conductive material.

6. The device of claim 1 , wherein the conductive pad includes a circular portion and lobes extending from the circular portion that define the circularly concave edge, a respective center of the circular portion of the conductive pad is to receive the solder joint connection.

7. The device of claim 1 , wherein the conductive pad is offset from the conductive via to form a circular boundary, the circular boundary being formed to minimize or reduce electrical connections associated with differential thermal expansion between the conductive via and the dielectric material, to prevent cracking or fractures of the solder joint of a ball grid array received at the conductive pad.

8. A device comprising:
a multilayer circuit board;
a plurality of solder pads positioned at a surface of the multilayer circuit board to receive solder joint connections to an electronic component;
a stacked via in the multilayer circuit board and exiting the multilayer circuit board at the surface at a position adjacent at least two solder pads of the plurality of solder pads; and
a trace connection at the surface of the multilayer circuit board connecting the stacked via to a first solder pad of the at least two solder pads;
wherein a second solder pad of the at least two solder pads includes a circularly concave edge that provides a gap with respect to a circularly convex edge of the stacked via,
wherein the circularly concave edge of the second solder pad and the circularly convex edge of the stacked via comprise respective circular segments that share a same circular center, wherein the circularly concave edge of the second solder pad and the circularly convex edge of the stacked via include complementary circular curvature that provide the gap with a constant width along an entirety of the circularly concave edge.

9. The device of claim 8 , wherein the first solder pad includes another circularly concave edge that provides another gap with respect to the circularly convex edge of the stacked via.

10. The device of claim 8 , wherein the second solder pad includes a plurality of circularly concave edges.

11. The device of claim 10 , wherein the plurality of circularly concave edges are evenly spaced about the periphery of the second solder pad.

12. The device of claim 10 , wherein the second solder pad includes a straight edge between two adjacent circularly concave edges of the plurality of circularly concave edges.

13. The device of claim 8 , wherein the second solder pad includes a plurality of lobes and a plurality of circularly concave edges, wherein adjacent pairs of lobes are separated by one of the plurality of circularly concave edges.

14. The device of claim 8 , further comprising:
an array of solder pads that includes the at least two solder pads; and
an array of candidate via locations arranged interstitially among to the array of solder pads;
wherein each solder pad of the array of solder pads includes a circularly concave edge next to each respective adjacent candidate via location to provide a gap between the solder pad and the respective adjacent candidate via location.

15. The device of claim 8 , wherein the first solder pad of the at least two solder pads includes a respective circularly concave edge that provides a respective gap with respect to the circularly convex edge of the stacked via,
wherein the respective circularly concave edge of the first solder pad and the circularly convex edge of the stacked via comprise further respective circular segments that share a respective same circular center, wherein the respective circularly concave edge of the first solder pad and the circularly convex edge of the stacked via include respective complementary circular curvature that provide the respective gap with a respective constant width along a respective entirety of the respective circularly concave edge, and
wherein the at least two solder pads include respective circular portions and respective lobes extending from the respective circular portions that define respective circularly concave edges, respective centers of the respective circular portions of the at least two solder pads are to receive respective solder joint connections.

16. The device of claim 8 , wherein the solder pads are offset from the stacked via to form respective circular boundaries, the respective circular boundaries formed to minimize or reduce electrical connections associated with differential thermal expansion between the stacked via and a dielectric material of the multilayer circuit board, to prevent cracking or fractures of the solder joint connections to a ball grid array received at the solder pads.

17. A device comprising:
a substrate;
an array of solder pads on a surface of the substrate to receive a ball grid array of an electronic component to be mounted to the substrate; and
an array of candidate via locations arranged interstitially among the array of solder pads;
wherein each candidate via location of the array of candidate via locations includes a circular boundary to space a circularly shaped via disposed at the candidate via location apart from any solder pads of the array of solder pads adjacent the candidate via location;
wherein a solder pad of the array of solder pads includes a circularly concave shape to accommodate the circular boundary of any adjacent candidate via location,
wherein the circularly concave shape of the s

Assignees

• Motorola Solutions Inc

Inventors

• Bradley Edwin L
• Suppelsa Anthony J
• Meyer David J

Classifications

• H10W90/701 Primary

  characterised by the relative positions of pads or connectors relative to package parts · CPC title

• H10W74/117

  the substrate having spherical bumps for external connection · CPC title

• H10W72/20

  Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps · CPC title

• H10W70/635

  Through-vias · CPC title

• H10W70/65

  Shapes or dispositions of interconnections · CPC title