Making solder ball mounting pads on substrates
First Claim
1. A substrate of an electronic device for mounting solder balls thereon, the substrate comprising:
- a sheet;
a metal layer on a surface of the sheet, the layer having a pattern in it defining a central pad therein, the pad having a plurality of spokes radiating outward therefrom; and
, a insulative mask over the metal layer, the mask having an opening therein, the opening exposing the pad and a portion of each of the spokes therethrough.
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Accused Products
Abstract
The invention discloses a method of making solder ball mounting pads on a substrate that have better ball shear performance, ball thermal cycle reliability, ball attach yield, and ball positional tolerances, than the solder ball mounting pads of the prior art. The method includes providing a sheet of material having a layer of metal thereon, and patterning the layer to define a solder ball mounting pad therein. The pad includes a central pad having at least two spokes radiating outward from it. An insulative mask is formed over the metal layer, and an opening is formed in the mask such that the central pad and an inner portion of each of the spokes is exposed therethrough, and an outer portion of each of the spokes is covered by the mask. In one embodiment, the central pad, spokes, and opening in the mask are shaped and arranged with respect to each other such that the pad and exposed portion of the spokes form a radially symmetrical pattern within the opening.
214 Citations
18 Claims
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1. A substrate of an electronic device for mounting solder balls thereon, the substrate comprising:
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a sheet;
a metal layer on a surface of the sheet, the layer having a pattern in it defining a central pad therein, the pad having a plurality of spokes radiating outward therefrom; and
,a insulative mask over the metal layer, the mask having an opening therein, the opening exposing the pad and a portion of each of the spokes therethrough. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A solder ball mounting for an electronic device, the mounting, comprising:
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a metal layer, including a central pad and at least two spokes radiating outward from the central pad;
a solder ball in a connection with the central pad and an inner portion of the at least two spokes; and
,an insulative layer surrounding the connection and covering an outer portion of the spokes. - View Dependent Claims (14)
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15. A method for making a solder ball mounting pad on a substrate, the method comprising:
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providing, a substrate having, a layer of metal thereon, the layer including a pattern defining a central pad with a plurality of spokes radiating outward therefrom; and
,covering an outer portion of the spokes with an insulating layer. - View Dependent Claims (16, 17)
forming an insulative mask over the metal layer; and
,forming an opening, in the mask that exposes the central pad and an inner end of each of the spokes therethrough.
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17. The method of claim 16, wherein each of the opening in the mask and the pattern in the metal layer exposed by the opening has a respective centroid, and further comprising positioning the respective centroids such that they are coincident with each other.
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18. A method for mounting a solder ball on an electronic device, the method comprising:
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providing an electronic device having a surface with a metal layer thereon, the metal layer including a pattern defining a central pad having a plurality of spokes radiating outward therefrom;
forming an insulative mask over the metal layer, the mask having an opening in it through which the central pad and an inner portion of each of the spokes is exposed; and
,reflowing a ball of solder on the central pad and the exposed portion of the spokes.
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Specification