Semiconductor Bonding Pad Structure for Reduced Dishing
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Solution Overview
Problem
The existing methods for manufacturing semiconductor devices face challenges in forming metal pads that are suitable for bonding, leading to issues such as increased chip thickness, higher manufacturing costs, and unevenness in shape, due to the need for thickening the metal pads to enhance thermal expansion, which complicates the etching process and polishing requirements.
Innovation Solution
The solution involves forming metal pads with a barrier metal layer that does not cover the upper or lower faces of the interconnection layers, allowing the pad material to directly contact the interconnection layers, thereby reducing dishing through thermal expansion and allowing for thinner pad thickness while maintaining effective bonding, and integrating the pad and interconnection material layers to achieve similar thermal expansion effects to thicker pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal pad thickness is increased to enhance thermal expansion, then the bonding suitability is improved, but the chip thickness increases and manufacturing cost increases
Solution Approach 1:
The patent merges the pad material layer and interconnection material layer into an integrated structure where the pad material layer directly contacts the interconnection layer without a barrier metal layer in between. This integration allows the combined structure to provide sufficient thermal expansion for bonding while reducing the overall chip thickness compared to having separate thick pad and interconnection layers.
Solution Approach 2:
The patent extracts the barrier metal layer from the pad structure, specifically removing it from the upper face of the pad material layer. This extraction allows the pad material to directly contact the interconnection material, enabling the pad to achieve necessary thermal expansion properties without requiring additional thickness from barrier layers.
2Reliability
If the metal pad thickness is increased to enhance thermal expansion, then the bonding suitability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent combines the pad material layer and interconnection material layer into a single integrated structure, eliminating the need for separate barrier metal layers. This merger reduces the number of manufacturing steps and material layers required, thereby lowering manufacturing costs while maintaining adequate thermal expansion for bonding.
Solution Approach 2:
The patent removes the barrier metal layer from the pad structure, simplifying the manufacturing process by reducing the number of deposition steps and material layers. This extraction lowers manufacturing complexity and cost while the integrated pad-interconnection structure maintains necessary thermal expansion properties.
3Stability of the object's composition
If the barrier metal layer covers the upper face of the pad material layer, then the pad structure is more complete, but the etching process becomes more complex and polishing requirements increase
Solution Approach 1:
The patent extracts the barrier metal layer from the upper face of the pad material layer, leaving only the necessary barrier metal at the interface between the pad material and substrate. This simplifies the etching process by reducing the number of different material layers that need to be selectively etched, and reduces polishing requirements by eliminating the need to planarize multiple stacked layers.
Solution Approach 2:
Instead of having the barrier metal layer cover the upper face of the pad material (conventional approach), the patent inverts this arrangement by having the pad material directly contact the interconnection material without an overlying barrier metal layer. This inversion simplifies subsequent processing steps while maintaining structural integrity.
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 enables the formation of metal pads suitable for bonding, reducing dishing and chip thickness, lowering manufacturing costs, and simplifying the etching and polishing processes, while maintaining effective thermal expansion properties.
Implementation Method 1
allowing the pad material to directly contact the interconnection layers, thereby reducing dishing through thermal expansion
Data Source
AI summary
In one embodiment, a semiconductor device includes a substrate, a first interconnection provided above the substrate, and a first pad provided on the first interconnection. The device further includes a second pad provided on the first pad, and a second interconnection provided on the second pad. Furthermore, the first pad includes a first layer provided in a first insulator above the substrate, and a second layer that is provided in the first insulator via the first layer and is in contact with the first interconnection, or the second pad includes a third layer provided in a second insulator above the substrate, and a fourth layer that is provided in the second insulator via the third layer and is in contact with the second interconnection.