Semiconductor device and a process for forming the semiconductor device
AssigneeMotorola, Inc.
InventorStuart E. Greer
Life of this patent
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Abstract
Conductive bumps (32) are formed to overlie a semiconductor die (11). The conductive bumps (32) typically have reduced levels of lead, flow at a temperature no greater than 260° C., and have reduced problems associated with alpha particles. In one embodiment, the conductive bump (32) includes a mostly tin (20) with a relatively thin layer of lead (30). The lead (30) and a portion of the tin (20) interact to form a relatively low melting solder close to the eutectic point for lead and tin. Most of the tin (20) remains unreacted and can form a stand off between the semiconductor die (11) and the packaging substrate (42). Other metals and impurities can be used to improve the mechanical or electrical properties of the conductive bumps (32).
Claims20
A process for forming a semiconductor die comprising:
- forming a die interconnect pad over a semiconductor device substrate;
- and
- forming a conductive bump over and electrically connected to the die interconnect pad, wherein:
- the conductive bump includes a first metallic layer and a second metallic layer, wherein:
- the first metallic portion lies closer to the semiconductor die compared to the second metallic portion, is a main portion of the conductive bump, and does not substantially include lead;
- and
- the second metallic portion is a farthest metallic portion of the conductive bump with respect to the semiconductor die, and wherein the second metallic portion includes lead.
A process for forming a semiconductor die comprising:
- placing a semiconductor die and a substrate in contact with each other, wherein:
- the semiconductor includes a die interconnect pad and a conductive bump including a first metallic layer and a second metallic layer;
- the first metallic layer lies closer to the semiconductor die compared to the second metallic layer, is a main portion of the conductive bump and does not substantially include lead;
- and
- the second metallic portion is a farthest metallic portion of the conductive bump with respect to the semiconductor die and includes lead;
- and
- flowing a portion, but not all, of the conductive bump.
A process for forming a semiconductor die comprising:
- forming a die interconnect pad over a semiconductor device substrate;
- and
- forming a conductive bump over and electrically connected to the die interconnect pad, wherein:
- the conductive bump includes a first metallic layer and a second metallic layer, wherein:
- the first metallic portion lies closer to the semiconductor die compared to the second metallic portion;
- the first metallic portion and the second metallic portion are of different materials;
- the second metallic portion contains lead;
- and
- the conductive bump includes less than approximately 25 weight percent lead .
A process for forming a semiconductor die comprising:
- placing a semiconductor die and a substrate in contact with each other, wherein:
- the semiconductor includes a die interconnect pad and a conductive bump including a first metallic layer and a second metallic layer, wherein:
- the first metallic portion lies closer to the semiconductor die compared to the second metallic portion;
- the first metallic portion and the second metallic portion are of different materials;
- the second metallic portion contains lead;
- and
- the conductive bump includes less than approximately 25 weight percent lead;
- and
- flowing a portion, but not all, of the conductive bump.
Dependencies are inferred from the claim text.