Method of forming stacked-die integrated circuit
First Claim
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1. An integrated circuit device, comprising:
- a first die having circuitry formed in a first surface;
a plurality of through-die vias formed in the first die, at least one through-die via of the plurality of through-die vias providing electrical connection between the circuitry of the first die and a second surface of the first die;
a first plurality of contact pads formed in the second surface of the first die; and
a second die mounted on the first die, the second die having circuitry and a second plurality of contact pads that are soldered to corresponding ones of the first plurality of contact pads;
wherein first contact pads of the first plurality of contact pads and the corresponding contact pads of the second plurality of contact pads provide electrical connection between the circuitry of the first die and the circuitry of the second die by means of a through-die via; and
wherein second contact pads of the first plurality of contact pads and the corresponding contact pads of the second plurality of contact pads are electrically isolated from the circuitry of the first die and electrically isolated from the circuitry of the second die.
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Abstract
A stacked-die integrated circuit and a method of fabricating same. The stacked-die integrated circuit has circuitry formed in the first surface of a mother die, a plurality of through-die vias with at least one through-die via providing electrical connection between the circuitry of the mother die and the second surface and a plurality of contact pads formed in the second surface of the semiconductor die for mounting a daughter die wherein some of the contact pads are electrically isolated dummy pads.
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Citations
15 Claims
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1. An integrated circuit device, comprising:
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a first die having circuitry formed in a first surface; a plurality of through-die vias formed in the first die, at least one through-die via of the plurality of through-die vias providing electrical connection between the circuitry of the first die and a second surface of the first die; a first plurality of contact pads formed in the second surface of the first die; and a second die mounted on the first die, the second die having circuitry and a second plurality of contact pads that are soldered to corresponding ones of the first plurality of contact pads; wherein first contact pads of the first plurality of contact pads and the corresponding contact pads of the second plurality of contact pads provide electrical connection between the circuitry of the first die and the circuitry of the second die by means of a through-die via; and wherein second contact pads of the first plurality of contact pads and the corresponding contact pads of the second plurality of contact pads are electrically isolated from the circuitry of the first die and electrically isolated from the circuitry of the second die. - View Dependent Claims (2, 3, 4)
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5. An integrated circuit device, comprising:
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a semiconductor mother die comprising circuitry formed in a first surface and a first plurality of contact pads formed in a second surface, at least one of the first plurality of contact pads being electrically connected to the circuitry by means of a through-die via and at least one of the first plurality of contact pads being electrically isolated from the circuitry; a daughter die mounted to the mother die and comprising circuitry and a second plurality of contact pads; an array of solder bumps bonding the second plurality of contact pads of the daughter die to the corresponding contact pads of the first plurality of contact pads of the mother die; wherein the at least one contact pad of the first plurality of contact pads that is electrically isolated from the circuitry of the mother die and the corresponding contact pad of the second plurality of contact pads is electrically isolated from the circuitry of the mother die and electrically isolated from the circuitry of the daughter die. - View Dependent Claims (6, 7, 8, 9)
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10. A method of fabricating a stacked-die integrated circuit device, comprising:
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forming a semiconductor mother die, wherein the mother die comprises circuitry and a first plurality of contact pads, at least one contact pad of the first plurality of contact pads being electrically connected to the circuitry by means of a through-die via and at least one contact pad of the first plurality of contact pads being electrically isolated from the circuitry of the mother die; forming a semiconductor daughter die, wherein the daughter die comprises circuitry and a second plurality of contact pads; and mounting the daughter die to the mother die with an array of solder bumps bonding the second plurality of contact pads of the daughter die to the corresponding contact pads of the first plurality of contact pads of the mother die such that the circuitry of the daughter die is electrically coupled to the circuitry of the mother die; wherein the at least one contact pad of the first plurality of contact pads that is electrically isolated from the circuitry of the mother die and the corresponding contact pad of the second plurality of contact pads is electrically isolated from the circuitry of the mother die and electrically isolated from the circuitry of the daughter die. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification