Semiconductor Via Pad Structure for Oxidation-Stable Interconnects
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Solution Overview
Problem
Conventional semiconductor structures face challenges in maintaining conductivity and stability due to oxidation of conductive pads and high aspect ratios of via structures, leading to reduced yield rates during manufacturing.
Innovation Solution
The semiconductor structure employs a first conductive pad with a second conductive pad of lower chemical reactivity, formed of different materials, to protect against oxidation and reduce the aspect ratio of via structures by using a dielectric layer and forming the second conductive pad in an opening, ensuring increased conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-layer conductive pad structure is used, then the manufacturing process is simple, but the conductive pad is prone to oxidation and conductivity deteriorates
Solution Approach 1:
The patent applies composite materials by forming a multi-layer conductive pad structure where a first conductive pad (e.g., copper with high conductivity) is combined with a second conductive pad (e.g., tungsten or gold with low chemical reactivity). This composite structure maintains high conductivity while the second layer protects against oxidation, resolving the contradiction between reliability and simplicity.
Solution Approach 2:
The second conductive pad acts as an intermediary protective layer between the first conductive pad and the external environment. This mediator layer prevents direct exposure of the highly reactive first conductive pad to oxidizing conditions, thereby maintaining conductivity stability without requiring complex protective measures.
2Manufacturing precision
If a via structure with high aspect ratio is used, then the vertical connection is achieved, but the yield rate decreases due to manufacturing difficulties
Solution Approach 1:
The patent changes the geometric parameters of the via structure by reducing the aspect ratio through optimized via diameter and depth dimensions. This parameter adjustment makes the via structure more manufacturable with standard processes, thereby increasing yield rate while still achieving the required vertical electrical connection functionality.
3Reliability
If the second conductive pad is formed with greater thickness, then oxidation protection is enhanced, but the aspect ratio of via structures increases
Solution Approach 1:
The patent optimizes the thickness parameter of the second conductive pad to achieve the minimum required protection against oxidation while keeping the via aspect ratio within manufacturable limits. This balanced parameter selection resolves the contradiction between adequate protection and acceptable via geometry.
Solution Approach 2:
The second conductive pad is strategically positioned and dimensioned to provide localized protection exactly where needed at the via interface, rather than uniformly throughout. This localized quality approach provides sufficient oxidation protection without unnecessarily increasing the via aspect ratio.
Data Source
AI summary
The present disclosure provides a method for manufacturing a semiconductor structure employing a via structure. The method includes forming a first conductive pad on a first semiconductor device; forming a second conductive pad on the first conductive pad; connecting a second semiconductor device to the first semiconductor device; and forming a via structure in the second semiconductor device, The via structure contacts the second conductive pad, and the first conductive pad and the second conductive pad are formed of different metal materials.