Method and apparatus for electroless plating a contact pad
First Claim
1. A method for plating a conductive layer in an integrated circuit, comprising:
- immersing the integrated circuit in a cleaning fluid comprising a reducing agent that etches oxide from the conductive layer; and
transferring the integrated circuit from the cleaning fluid to a separate plating fluid without exposing the integrated circuit to air, wherein transferring comprises passing the integrated circuit from the cleaning fluid directly to a second fluid that selectively forms a protective layer on an insulating material surrounding the conductive layer, and the plating fluid selectively forms a conducting material on the conductive layer.
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Accused Products
Abstract
A method and apparatus is disclosed for sequential processing of integrated circuits, particularly for conductively passivating a contact pad with a material which resists formation of resistive oxides. In particular, a tank is divided into three compartments, each holding a different solution: a lower compartment and two upper compartments divided by a barrier, which extends across and partway down the tank. The solutions have different densities and therefore separate into different layers. In the illustrated embodiment, integrated circuits with patterned contact pads are passed through one of the upper compartments, in which oxide is removed from the contact pads. Continuing downward into the lower compartment and laterally beneath the barrier, a protective layer is selectively formed on the insulating layer surrounding the contact pads. As the integrated circuits are moved upwardly into the second upper compartment, a conducting monomer selectively forms on the contact pads prior to any exposure to air. The integrated circuits can then be transferred to an ozone chamber where polymerization results in a conductive passivation layer on the contact pad.
96 Citations
23 Claims
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1. A method for plating a conductive layer in an integrated circuit, comprising:
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immersing the integrated circuit in a cleaning fluid comprising a reducing agent that etches oxide from the conductive layer; and
transferring the integrated circuit from the cleaning fluid to a separate plating fluid without exposing the integrated circuit to air, wherein transferring comprises passing the integrated circuit from the cleaning fluid directly to a second fluid that selectively forms a protective layer on an insulating material surrounding the conductive layer, and the plating fluid selectively forms a conducting material on the conductive layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A process for plating a contact pad in an integrated circuit, comprising:
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cleaning an oxide from the contact pad in a wet etch bath; and
transferring the integrated circuit from the wet etch bath directly to a second liquid phase treatment, the second liquid phase treatment selectively depositing a layer of conducting material over the cleaned contact pad, wherein the second liquid phase treatment comprises a first liquid subphase directly contacting and separate from the wet etch bath, wherein the first liquid subphase selectively forms a protective layer over an insulating material surrounding the contact pad, and a second liquid subphase directly contacting and separate from the first liquid subphase. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of forming a conductive passivation layer for a contact pad in an integrated circuit, the contact pad comprising a conductive layer exposed through a window in a surrounding insulating layer, the method comprising:
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providing a container having first, second and third liquid phases separated from one another;
immersing the integrated circuit in the first phase comprising an oxide etch bath wherein the conductive layer is cleaned;
transferring the integrated circuit from the first phase directly to the second phase, wherein a protective layer comprising a hydrophobic exposed surface is selectively formed on the insulating layer;
transferring the integrated circuit from the second phase directly to the third phase, wherein a monomer layer is selectively formed on the cleaned conductive layer; and
polymerizing the monomer layer. - View Dependent Claims (19, 20, 21, 22)
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23. A method for electroless plating a conductive polymer on a metal surface of a workpiece, the metal surface including an aluminum oxide layer, the method comprising:
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immersing the workpiece in a container holding a plurality of solutions, wherein each of said plurality of solutions is in contact with at least one other of said plurality of solutions, thereby allowing direct transfer of said workpiece between said plurality of solutions in said container;
exposing the metal surface to an oxide cleaning solution within the container;
preferentially forming a layer comprising a conducting monomer after exposing the metal surface to an oxide cleaning solution and prior to removing the workpiece from the container;
polymerizing said conducting monomer layer; and
selectively forming a hydrophobic upper surface over a non-metal material surrounding the metal surface prior to preferentially form the layer comprising a conducting monomer.
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Specification