Inductor Structure Selective Barrier Layers
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Solution Overview
Problem
Conventional inductor structures waste materials and increase total resistance due to the formation of unnecessary nickel and gold layers on all copper bumps, which are not all needed for electrical connection, thereby reducing the efficiency and inductance of the inductor.
Innovation Solution
The inductor structure includes a substrate with bond pads, a protection layer, a patterned conductive layer, copper bumps, a diffusion barrier layer, and an oxidation barrier layer, where the diffusion and oxidation barrier layers are only formed on selected copper bumps that need to be connected, using a manufacturing method that involves photoresist layers and electrolytic deposition to selectively apply these layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nickel layers and gold layers are formed on all copper bumps by electrolytic deposition, then the copper bumps are protected from oxidation and fusion, but material is wasted and the total resistance of the lines increases
Solution Approach 1:
The patent applies different treatments to different copper bumps based on their functional requirements. Only copper bumps that require electrical connection to BGA or conductive protruding blocks are covered with nickel and gold layers, while other copper bumps remain uncovered. This local differentiation eliminates material waste on non-essential bumps while maintaining protection where needed.
2Reliability
If nickel layers and gold layers are formed on all copper bumps by electrolytic deposition, then the copper bumps are protected from oxidation and fusion, but the total resistance of the lines increases and efficiency decreases
Solution Approach 1:
The invention selectively applies protective layers only to copper bumps that require electrical connection, leaving other bumps uncovered. This reduces the total resistance of the inductor structure by minimizing the amount of resistive material (nickel and gold layers) while still providing protection where electrical connection is needed.
3Reliability
If nickel layers and gold layers are formed on all copper bumps, then all copper bumps are protected, but the inductance of the inductor structure cannot be improved
Solution Approach 1:
By selectively applying protective layers only where necessary for electrical connection, the invention reduces overall resistance in the inductor structure. This reduction in resistance enables improvement of inductance performance, as the unnecessary resistive material is eliminated from non-essential copper bumps.
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
This approach saves material costs, reduces the total resistance of the inductor structure, and improves its efficiency and inductance by only forming the necessary barrier layers on the required copper bumps.
Implementation Method 1
The copper bumps are respectively formed on the bond pads by electrolytic deposition
Implementation Method 2
a nickel layer and a gold layer need to be formed in sequence by electrolytic deposition
Data Source
AI summary
A manufacturing method of an inductor structure includes the following steps. A protection layer is formed on a substrate, such that bond pads of the substrate are respectively exposed form protection layer openings of the protection layer. A conductive layer is formed on the bond pads and the protection layer. A patterned first photoresist layer is formed on the conductive layer. Copper bumps are respectively formed on the conductive layer located in the first photoresist layer openings. A patterned second photoresist layer is formed on the first photoresist layer, such that at least one of the copper bumps is exposed through second photoresist layer opening and the corresponding first photoresist layer opening. A diffusion barrier layer and an oxidation barrier layer are formed on the copper bump. The first and second photoresist layers, and the conductive layer not covered by the copper bumps are removed.