Buffer Layer for Reliable IC Interconnects
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Solution Overview
Problem
The challenge is to create reliable and cost-effective interconnects for high-speed integrated circuits (ICs) without compromising electrical or mechanical reliability, particularly in the interconnections of ICs, which is often compromised when aiming for high-speed signal transmission.
Innovation Solution
A semiconductor device with a contact region and a buffer layer over the last interconnect level, where a final passivation layer exposes the top surface of the contact region, allowing the buffer layer to absorb forces during electrically conductive interconnection, ensuring reliable bonding without damaging internal circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed signal transmission is achieved by reducing RC time constant, then signal transmission speed is improved, but electrical or mechanical reliability of interconnections is compromised
Solution Approach 1:
A buffer layer is introduced as an intermediary between the contact region and the bonding pad. This buffer layer absorbs forces exerted during interconnection formation, protecting the underlying contact region and internal circuitry while enabling reliable high-speed signal transmission through properly formed interconnections.
Solution Approach 2:
The buffer layer is positioned beforehand at the contact region to absorb forces that will be exerted during subsequent bonding processes. This pre-positioned cushioning prevents damage to the contact region and internal circuitry before the actual bonding occurs, ensuring both reliability and high-speed performance.
2Reliability
If buffer layer absorbs force during interconnection formation, then mechanical reliability is improved, but material diffusion may occur that reduces carrier lifetime
Solution Approach 1:
The buffer layer is formed with specific material properties and thickness parameters that allow it to absorb mechanical forces while maintaining barriers against material diffusion. By carefully controlling the buffer layer's physical and chemical parameters, both mechanical reliability and prevention of harmful material diffusion are achieved.
Solution Approach 2:
The buffer layer may be formed using composite materials that combine properties of force absorption with diffusion resistance. This composite structure enables the buffer layer to simultaneously protect against mechanical damage and prevent material diffusion that would harm carrier lifetime.
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 solution enables reliable electrical and mechanical interconnections for high-speed ICs, maintaining high transmission speed and avoiding material diffusion that could reduce carrier lifetime.
Implementation Method 1
the buffer layer absorbs a portion of a force exerted to form an interconnection between the electrically conductive interconnection and the contact region
Data Source
AI summary
Devices and methods for forming a device are disclosed. The device includes a contact region disposed over a last interconnect level of the device. The device includes a final passivation layer having at least an opening which at least partially exposes a top surface of the contact region and a buffer layer disposed at least over a first exposed portion of the top surface of the contact region. When an electrically conductive interconnection couples to the contact region, the buffer layer absorbs a portion of a force exerted to form an interconnection between the electrically conductive interconnection and the contact region.