Multilayer pillar for reduced stress interconnect and method of making same
First Claim
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1. A method of forming a copper interconnect pillar, the method comprising:
- forming a first copper layer on at least one other layer;
forming a first nickel barrier protective layer on the first copper layer and in direct contact with the first copper layer;
forming a substantially planar first intermediate layer on the first nickel barrier protective layer, the first intermediate layer having a first surface in direct contact with the first nickel barrier protective barrier layer, and having a modulus of elasticity lower than the first copper layer;
forming a second nickel barrier protective layer on a second surface of the first intermediate layer opposing the first surface of the first intermediate layer and in direct contact with the second surface of the first intermediate layer; and
forming a second copper layer on the second nickel barrier protective layer and in direct contact with a surface of the second nickel barrier layer opposing the first intermediate layer, the first intermediate layer having a modulus of elasticity lower than the second copper layer.
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Abstract
A multi-layer pillar and method of fabricating the same is provided. The multi-layer pillar is used as an interconnect between a chip and substrate. The pillar has at least one low strength, high ductility deformation region configured to absorb force imposed during chip assembly and thermal excursions.
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Citations
19 Claims
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1. A method of forming a copper interconnect pillar, the method comprising:
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forming a first copper layer on at least one other layer; forming a first nickel barrier protective layer on the first copper layer and in direct contact with the first copper layer; forming a substantially planar first intermediate layer on the first nickel barrier protective layer, the first intermediate layer having a first surface in direct contact with the first nickel barrier protective barrier layer, and having a modulus of elasticity lower than the first copper layer; forming a second nickel barrier protective layer on a second surface of the first intermediate layer opposing the first surface of the first intermediate layer and in direct contact with the second surface of the first intermediate layer; and forming a second copper layer on the second nickel barrier protective layer and in direct contact with a surface of the second nickel barrier layer opposing the first intermediate layer, the first intermediate layer having a modulus of elasticity lower than the second copper layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of bonding a chip to a substrate utilizing at least one multi-layer copper interconnect pillar, comprising:
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providing a chip having a barrier and adhesion layer; forming a seed layer on the barrier and adhesion layer, the seed layer comprising one of chromium copper and copper; forming a first copper layer directly on and in contact with the seed layer; forming an entirely planar first intermediate layer directly on the first copper layer, the entirely planar first intermediate layer having a modulus of elasticity lower than the first copper layer; forming a second copper layer directly on the entirely planar first intermediate layer, the first intermediate layer having a modulus of elasticity lower than the second copper layer; forming an entirely planar second intermediate layer in contact with the second copper layer; forming a third copper layer in contact with the entirely planar second intermediate layer; and bonding the resulting structure to a substrate. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of bonding a chip to a substrate utilizing at least one multi-layer copper interconnect pillar, comprising:
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providing a chip having a barrier and adhesion layer; forming a seed layer on the barrier and adhesion layer, the seed layer comprising one of chromium copper and copper; forming a first copper layer on the barrier and adhesion layer; forming an entirely planar first intermediate layer directly on the first copper layer, the entirely planar first intermediate layer having a modulus of elasticity lower than the first copper layer; forming a second copper layer directly on the first intermediate layer, the first intermediate layer having a modulus of elasticity lower than the second copper layer; forming an entirely planar second intermediate layer in contact with the second copper layer; forming a third copper layer in contact with the entirely planar second intermediate layer, and bonding the resulting structure to a substrate, wherein the entirely planar first intermediate layer is a single chemical element comprising one of gold, silver and aluminum.
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Specification