Redistribution Layer Void Partitioning for Lower Inter-Wiring Capacitance
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Solution Overview
Problem
In semiconductor devices, forming a void between wiring layers is challenging when the direction of the wiring and the chemical liquid flow are parallel, leading to increased inter-wiring capacitance, which hinders high-speed operation.
Innovation Solution
A semiconductor device with a redistribution layer and a manufacturing method that alternately form partitions and voids between wiring layers using an insulating material, preventing the protective film from entering the gaps and reducing inter-wiring capacitance by increasing the contact area with air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wiring is made finer for high-speed operation, then speed is improved, but inter-wiring capacitance increases which hinders high-speed operation
Solution Approach 1:
The space between adjacent wirings is segmented into multiple voids by introducing partition structures. This segmentation allows the chemical liquid to be excluded from specific regions between wirings, creating multiple air-filled voids that reduce inter-wiring capacitance more effectively than a single continuous void space.
Solution Approach 2:
Partition structures act as intermediary elements between adjacent wirings. These partitions serve as barriers that prevent the chemical liquid from directly contacting the wiring surfaces in certain regions, thereby creating voids that reduce capacitance while the partitions themselves provide structural support and electrical isolation.
2Object-affected harmful factors
If a void is formed between wiring pieces by spin coating, then inter-wiring capacitance is reduced, but the void formation is unreliable when wiring direction and chemical liquid flow are parallel
Solution Approach 1:
Partition structures are formed in advance before the spin coating process. These pre-formed partitions act as physical barriers that guide the chemical liquid flow and prevent it from entering the spaces between wirings regardless of the flow direction. This preliminary structuring ensures reliable void formation without depending on the alignment between wiring direction and chemical liquid flow.
Solution Approach 2:
The partition structures automatically perform the function of void formation during the spin coating process. As the chemical liquid spreads across the substrate, the partitions naturally block the liquid from entering the wiring gaps, causing voids to form self-organizing between the partitions and wirings without requiring precise alignment control.
3Reliability
If partitions are alternately formed with voids between wiring pieces, then void formation reliability is improved, but device structure becomes more complex
Solution Approach 1:
The partition structures serve multiple functions simultaneously: they act as barriers to chemical liquid flow, provide structural support between wirings, offer electrical isolation, and define the boundaries of void regions. By merging these multiple functions into a single structural element, the overall device complexity is minimized while achieving reliable void formation.
Solution Approach 2:
The partitions are designed as multi-functional elements that perform void formation, electrical insulation, mechanical support, and flow guidance functions. This universal design approach allows a single structural feature to address multiple requirements, reducing the need for additional separate components and simplifying the overall device architecture.
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 solution effectively reduces inter-wiring capacitance by ensuring a void is formed between the wiring layers, allowing for stable high-speed operation of semiconductor devices.
Implementation Method 1
a chemical liquid is dropped to the center of a semiconductor wafer, and the chemical liquid is substantially uniformly applied to an entire semiconductor wafer surface by a centrifugal force of the semiconductor wafer
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a wiring layer including an electrode pad, the wiring layer formed on a first surface of the semiconductor substrate, a redistribution layer including wiring electrically connected to the electrode pad via a via, the redistribution layer formed on a second surface side opposite to the first surface of the semiconductor substrate, a protective film formed on a surface on a side opposite to the semiconductor substrate in the redistribution layer, and a partition formed by an insulating material, the partition arranged between pieces of wiring in the redistribution layer, in which the partition and a void are alternately formed between the pieces of wiring in a direction in which the wiring extends.