Semiconductor Bonding Pad Nickel Gold Plating for Peeling Prevention
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, leading to issues with bonding pad reliability during wire bonding and ball shear tests.
Innovation Solution
A semiconductor device structure is formed by creating a nickel layer over a bonding pad to prevent peeling and a gold layer on top to buffer bonding stress, using electroless plating and immersion plating processes respectively, which enhances the reliability of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process difficulty increases and bonding pad reliability deteriorates
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of a bonding pad layer (first material) and a nickel layer (second material) deposited over it. This composite structure combines the electrical conductivity of the bonding pad with the stress-buffering properties of nickel, preventing peeling during wire bonding and ball shear tests while maintaining functionality at scaled dimensions.
Solution Approach 2:
The patent implements beforehand cushioning by depositing a nickel layer over the bonding pad before wire bonding or ball bonding processes. This nickel layer acts as a cushion that absorbs and distributes bonding stress, preventing peeling failures that would occur with direct bonding to the bonding pad alone, thereby ensuring reliability in advance of the actual bonding operation.
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing electroless nickel plating on the bonding pad before subsequent wire bonding or ball bonding operations. This preliminary deposition of nickel creates a protective and stress-absorbing layer that simplifies later bonding processes by preventing peeling failures, thereby reducing overall fabrication complexity despite the additional plating step.
3Reliability
If a nickel layer is deposited over a bonding pad to prevent peeling, then bonding pad reliability improves, but device structure complexity increases
Solution Approach 1:
The patent uses composite materials by combining the bonding pad layer (first material) with a nickel layer (second material) deposited over it. This composite structure maintains bonding pad functionality while adding stress-buffering capabilities, achieving improved reliability without significant structural complexity because the nickel layer conformally follows the bonding pad geometry.
Solution Approach 2:
The nickel layer serves as an intermediary between the bonding pad and subsequent bonding elements (wire or ball). It mediates the stress distribution during bonding operations, preventing direct stress concentration on the bonding pad that would cause peeling, thereby improving reliability while adding only a thin functional layer rather than a complex structure.
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 nickel layer prevents bonding pad peeling, while the gold layer buffers stress, improving the reliability and yield of the semiconductor device structure during wire bonding and ball bonding processes.
Implementation Method 1
A nickel layer is formed over the bonding pad
Implementation Method 2
A gold layer is formed over the nickel layer
Data Source
AI summary
A semiconductor device structure is provided, in some embodiments. The semiconductor device structure includes a semiconductor substrate having a first surface, a second surface, and sidewalls defining a recess that passes through the semiconductor substrate. The semiconductor device structure further includes an interconnect structure having one or more interconnect layers within a first dielectric structure that is disposed along the second surface. A conductive bonding structure is disposed within the recess and includes nickel. The conductive bonding structure has opposing outermost sidewalls that contact sidewalls of the interconnect structure.