Semiconductor Bonding Pad Structure to Prevent CMP Dishing
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Solution Overview
Problem
The issue of dishing during chemical mechanical polishing (CMP) leads to increased contact resistance and open circuit failures between semiconductor chip bonding pads, due to material quality differences.
Innovation Solution
The implementation of insulating materials within the conductive pads, acting as supporting posts during CMP, to prevent dishing and maintain flush contact surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP method is used for polishing bonding surfaces, then surface flatness is improved, but dishing occurs due to material quality differences
Solution Approach 1:
The patent applies local quality by forming insulating materials at specific locations within the pad structure. These insulating materials are positioned at the pad center or in specific regions to provide localized support during CMP, preventing dishing in critical areas while maintaining overall surface flatness.
Solution Approach 2:
The patent uses composite materials by combining conductive materials (for electrical connection) with insulating materials (for structural support) within the pad structure. This composite construction allows the pad to maintain its electrical functionality while the insulating components prevent dishing during CMP processing.
2Reliability
If dishing occurs on bonding pads, then contact resistance increases, but electrical connectivity is compromised
Solution Approach 1:
The insulating materials are strategically positioned in specific regions of the pad to maintain the flatness of the bonding surface. This localized support prevents dishing at critical contact areas, ensuring reliable electrical connectivity while maintaining low contact resistance.
Solution Approach 2:
The insulating materials are formed in advance during the pad fabrication process, before CMP is performed. This preliminary action ensures that the protective structure is already in place to prevent dishing during subsequent polishing operations, maintaining both electrical connectivity and contact resistance specifications.
3Shape
If insulating materials are added to pads, then dishing is prevented, but pad structure complexity increases
Solution Approach 1:
Rather than modifying the entire pad structure, the patent introduces insulating materials only in specific locations where dishing prevention is most critical. This localized approach maintains pad flatness while minimizing the increase in overall structural complexity.
Solution Approach 2:
The insulating materials are integrated within the existing pad structure, nesting the protective function inside the conductive pad. This nested configuration allows the insulating materials to provide dishing prevention without significantly increasing the external dimensions or complexity of the pad 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
This approach reduces dishing, stabilizes contact resistance, and ensures reliable electrical connectivity between semiconductor chips.
Implementation Method 1
In a polishing method such as a CMP (Chemical Mechanical Polishing) method, dishing (a recess) sometimes occurs due to a difference in the quality of materials to be polished.
Data Source
AI summary
A semiconductor device according to the present embodiment includes a substrate having a first semiconductor circuit provided thereon. First pads are located on the substrate. A first insulating layer is located on an outer side of each of the first pads. Second pads are respectively bonded to the first pads. A second insulating layer is located on an outer side of each of the second pads and is bonded to the first insulating layer. The first pads each include a first conductive material, and a first insulating material located on an inner side of the first conductive material on a bonding surface of the first pads and the second pads.