Solder interface locking using unidirectional growth of an intermetallic compound
First Claim
Patent Images
1. A ball grid array device comprising:
- a substrate, further including;
a first major surface; and
a second major surface; and
an array of pads positioned on one of the first major surface or the second major surface, at least some of the pads including a barrier layer thereon, the barrier layer made of a material that forms an intermetallic material with a solder, the barrier layer having a plurality of openings therein over the surface of at least one of the array of pads.
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Abstract
A ball grid array device includes a substrate, further including a first major surface and a second major surface. An array of pads is positioned on one of the first major surface or the second major surface. At least some of the pads include a barrier layer having pores or openings therein. When solder is placed on the pad, the barrier layer forms an intermetallic compound at a rate different from the rate of the intermetallic compound formed between the pad and the solder. The result is a solder ball on a pad that has a first intermetallic compound and a second intermetallic compound.
17 Citations
25 Claims
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1. A ball grid array device comprising:
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a substrate, further including; a first major surface; and a second major surface; and an array of pads positioned on one of the first major surface or the second major surface, at least some of the pads including a barrier layer thereon, the barrier layer made of a material that forms an intermetallic material with a solder, the barrier layer having a plurality of openings therein over the surface of at least one of the array of pads. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, 19, 20, 21, 22)
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13. The ball grid array device comprising:
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a substrate, further including; a first major surface; and a second major surface; an array of pads positioned on one of the first major surface or the second major surface, at least some of the pads including a barrier layer, a solderball formed on the pads having a barrier layer, wherein the barrier layer has a plurality of openings therein, the barrier layer material forming a first intermetallic compound with the solder at a first rate, and the pad material forming a second intermetallic compound with the solder at a second rate, and wherein one of the first intermetallic compound and the second intermetallic compound forms a finger extending from the plurality of openings in the barrier layer and into the solderball further from the barrier than the other of the first intermetallic compound and the second intermetallic compound. - View Dependent Claims (14)
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23. A ball grid array device comprising:
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a substrate, further including; a first major surface; and a second major surface; and an array of pads positioned on one of the first major surface or the second major surface, at least some of the pads including; a first material capable of forming a first intermetallic material with a solder; and a second material capable of forming a second intermetallic material with the solder, the first and second material at the exposed surface of the pad. - View Dependent Claims (24, 25)
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Specification