Multilayered Semiconductor Contact Structure for Adhesive Transfer Resistance
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Solution Overview
Problem
Traditional copper contact technology in semiconductor chip-to-package interconnects reacts poorly with adhesives, resulting in non-wettable surfaces, which hinders electrical connections and electromigration performance.
Innovation Solution
A multilayered contact structure comprising a Nickel layer, a Copper layer, and a Nickel-Iron or Tin layer is formed, which inhibits adhesive transfer and ensures wettable surfaces for improved solder attachment, enhancing electrical interfaces and electromigration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional copper contacts are used, then the contact structure is simple and manufacturing is easy, but the adhesive transfer is excessive and surfaces become non-wettable
Solution Approach 1:
The contact structure is divided into multiple functional layers: a copper core layer for electrical conductivity, a nickel intermediate layer for adhesive transfer resistance, and a tin outer layer for solder wetting. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between manufacturing simplicity and adhesive transfer resistance.
Solution Approach 2:
The invention uses a composite multilayer structure combining copper, nickel, and tin layers. Each material contributes its unique properties: copper provides conductivity, nickel prevents adhesive transfer, and tin ensures solder wetting. This composite approach maintains ease of manufacture through standard plating processes while achieving superior adhesive transfer resistance and wetting properties.
2Productivity
If adhesive is applied to the wafer, then chip fabrication can proceed, but adhesive transfers to the contact surfaces making them non-wettable
Solution Approach 1:
The nickel intermediate layer acts as a mediator between the copper core and the external environment. It provides a surface that resists adhesive transfer while the tin outer layer ensures subsequent solder wetting. This intermediary structure allows the chip fabrication process to proceed with adhesive application while protecting the contact surfaces from adhesive contamination.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multilayered contact structure prevents adhesive transfer and ensures wettable surfaces, improving electrical connections and electromigration performance in semiconductor chip-to-package assemblies.
Implementation Method 1
forming a barrier layer upon a dielectric layer, forming an electrically conductive plating layer upon the barrier layer, and forming a multilayered contact upon the plating layer
Implementation Method 2
plating a Nickel-Iron layer upon the Nickel layer, plating a Tin layer upon the Nickel layer... ensures wettable surfaces for improved solder attachment
Data Source
AI summary
A three dimensional multi-die package includes a first die and second die. The first die includes a contact attached to solder. The second die is thinned by adhesively attaching a handler to a top side of the second die and thinning a bottom side of the second die. The second die includes a multilayer contact of layered metallurgy that inhibits transfer of adhesive thereto. The layered metallurgy includes at least one layer that is wettable to the solder. The multilayer contact may include a Nickel layer, a Copper layer upon the Nickel layer, and a Nickel-Iron layer upon the Copper layer. The multilayer contact may also include a Nickel layer, a Copper-Tin layer upon the Nickel layer, and a Tin layer upon the Copper-Tin layer.