Displaced Cu Electrode Pad Structure Suppressing Pumping
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Solution Overview
Problem
Cu electrodes in semiconductor devices experience volume variations due to thermal expansion, leading to Cu pumping, which degrades bonding characteristics and reliability, especially when the Cu electrode volume connected to lower-layer metal is larger than dummy Cu electrodes.
Innovation Solution
A semiconductor device design where the Cu electrode pad is formed in a location displaced from the electrode via, with the electrode via serving as a connection member to the lower-layer metal, and an electrically conductive metal, such as aluminum or tungsten, is used to connect the electrode via to the Cu electrode pad, ensuring the Cu electrode pad is not directly influenced by thermal expansion stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the Cu electrode volume connected to lower-layer metal is increased to achieve stronger bonding, then the bonding strength is improved, but Cu pumping occurs due to thermal expansion volume variations
Solution Approach 1:
The Cu electrode structure is segmented into two distinct parts: a Cu electrode pad at the bonding surface and a Cu electrode via connected to lower-layer metal. This segmentation allows the Cu electrode via to be isolated from the bonding surface, preventing thermal expansion stress from causing Cu pumping while maintaining sufficient Cu volume in the via for strong bonding.
Solution Approach 2:
An electrically conductive metal layer is introduced as an intermediary between the Cu electrode via and the Cu electrode pad. This intermediary layer electrically connects the Cu electrode via to the Cu electrode pad while preventing direct mechanical coupling, thereby isolating the Cu electrode pad from thermal expansion stress of the Cu electrode via and suppressing Cu pumping.
2Manufacturing precision
If dummy Cu electrodes are added to suppress dishing and erosion, then planarity is improved, but the Cu volume increases leading to Cu pumping
Solution Approach 1:
The Cu electrode structure is segmented into a Cu electrode pad at the bonding surface and a Cu electrode via below. This segmentation allows the Cu electrode via to serve as a dummy electrode for suppressing dishing and erosion during CMP while being spatially separated from the bonding surface, thereby preventing it from causing Cu pumping.
Solution Approach 2:
The Cu electrode via is positioned in a different spatial dimension (below the bonding surface) relative to the Cu electrode pad. This dimensional separation allows the Cu electrode via to function as a dummy electrode for planarity control while being isolated from the bonding surface to prevent Cu pumping.
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 design effectively suppresses Cu pumping, enhancing bonding characteristics and reliability by preventing the influence of Cu volume thermal expansion stress on the Cu electrode pad, thereby maintaining robust connections between semiconductor members.
Implementation Method 1
an electrode via, the electrode via being a connection member that connects the Cu electrode pad to a lower-layer metal
Implementation Method 2
Cu has a characteristic of undergoing variations in volume in accordance with the coefficient of thermal expansion, and therefore, when the volume of Cu electrodes and Cu dummy electrodes is large, Cu pumping tends to occur because the volume increases in accordance with the coefficient of thermal expansion
Data Source
AI summary
Provided is a semiconductor device, a manufacturing method, and an electronic device designed to suppress the occurrence of Cu pumping. The semiconductor device includes a Cu electrode pad serving as a bonding surface for bonding a plurality of semiconductor members together and an electrode via, the electrode via being a connection member that connects the Cu electrode pad to a lower-layer metal. The Cu electrode pad is formed in a location displaced from the electrode via.