Semiconductor Bonding Structure With Tungsten-Mediated Cu-Al Interface
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Solution Overview
Problem
The conventional semiconductor manufacturing process faces high interface resistance and manufacturing challenges due to the immature copper-aluminum interface, particularly in DRAM chips, which affects bonding quality and yield.
Innovation Solution
Introducing a tungsten element between the copper and aluminum elements to create a copper-tungsten-aluminum heterogeneous interface, dividing the interface into mature copper-tungsten and tungsten-aluminum interfaces, thereby improving conductivity and manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper-aluminum heterogeneous interface is used to reduce cost, then material cost is reduced, but interface resistance increases and manufacturing reliability deteriorates
Solution Approach 1:
A tungsten element is introduced as an intermediary between copper and aluminum bonding pads, creating a copper-tungsten-aluminum heterogeneous contact combination. The tungsten element serves as a mediator that bridges the two dissimilar metals, reducing interface resistance and improving bonding reliability while maintaining cost benefits from the aluminum-copper heterogeneous structure
Solution Approach 2:
The invention creates a composite contact structure consisting of copper, tungsten, and aluminum elements in a stacked configuration. This composite material approach combines the advantages of each material: copper for conductivity, tungsten for low resistance and process compatibility, and aluminum for cost-effectiveness, achieving both cost reduction and reliability improvement
2Quantity of substance
If copper-aluminum heterogeneous interface is used, then cost is reduced, but manufacturing precision deteriorates due to immature process
Solution Approach 1:
The tungsten element acts as an intermediary layer that simplifies the manufacturing process by providing a well-established deposition and patterning methodology. This intermediary layer enables precise interface formation using mature semiconductor fabrication techniques, improving manufacturing precision while maintaining the cost benefits of heterogeneous materials
Solution Approach 2:
The invention changes the material parameter at the interface by introducing tungsten, which has favorable deposition characteristics and process compatibility. This parameter change enables the use of mature manufacturing processes with precise control over layer thickness, composition, and interface quality, thereby improving manufacturing precision
3Reliability
If copper bonding pads are used to improve bonding quality, then bonding quality is improved, but material cost increases
Solution Approach 1:
The invention applies local quality by using copper specifically at the bonding pad interfaces where high conductivity and bonding quality are critical, while using cost-effective aluminum for the horizontal metal traces and vertical via structures where extreme conductivity is less critical. This localized material optimization achieves both bonding quality improvement and cost reduction
Solution Approach 2:
The heterogeneous contact combination creates a composite structure that leverages the superior bonding and conductivity properties of copper at critical interfaces while utilizing the cost advantages of aluminum in less critical areas, achieving both bonding quality improvement and material cost reduction
Data Source
AI summary
The invention provides a semiconductor bonding structure, the semiconductor bonding structure includes a first chip and a second chip which are bonded with each other, the first chip has a first bonding pad and the second bonding pad contacted and electrically connected to each other on a bonding interface, the first bonding pad and the second bonding pad are made of copper, and a heterogeneous contact combination in the first chip, the heterogeneous contact combination comprises a contact stack structure of a copper element, a tungsten element and an aluminum element, the tungsten element is located between the copper element and the aluminum element.