Semiconductor Electrode Diffusion Barrier for Au-Sn Solder Reliability
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Solution Overview
Problem
Conventional semiconductor devices face challenges in ensuring reliable electrical connection and preventing material diffusion issues due to the formation of through holes in semiconductor substrates, which can lead to corrosion, deformation, and disconnection of electrodes during mounting.
Innovation Solution
A semiconductor device and manufacturing method involving a semiconductor substrate with a junction layer, diffusion-suppressing layer, and pad layer, where a through hole is formed below the source electrode, and grounding wiring is placed on the back surface and inner hole surface, using a diffusion-suppressing layer to prevent Au diffusion into Au—Sn solder, forming an intermetallic compound to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through hole is formed in the semiconductor substrate to provide grounding connection, then electrical connection reliability is improved, but material diffusion and electrode corrosion occur leading to device degradation
Solution Approach 1:
A diffusion barrier layer is introduced as an intermediary between the Au-Sn solder and the electrode structure. This barrier layer prevents direct contact and diffusion reactions, blocking Au atoms from migrating into the electrode and preventing corrosion while maintaining the grounding connection function through the through-hole structure.
Solution Approach 2:
The harmful diffusion and corrosion processes are extracted and prevented by removing the direct interaction pathway between the solder and electrode. The diffusion barrier layer effectively separates these two components, eliminating the harmful material exchange while preserving the beneficial electrical connection.
2Reliability
If Au-Sn solder is used for mounting the semiconductor device, then electrical connection is achieved, but Au diffusion into the solder causes corrosion and deformation
Solution Approach 1:
The diffusion barrier layer serves as a mediator that allows electrical connection to be maintained while preventing the harmful diffusion of Au into the solder. It creates a controlled interface that enables functional connectivity without material degradation.
3Reliability
If the through hole penetrates deeply into the semiconductor substrate, then grounding conductor contact is improved, but etching precision and structural integrity become difficult to control
Solution Approach 1:
The diffusion barrier layer is formed in advance on the inner surface of the through hole before the grounding conductor is deposited. This preliminary action ensures that the barrier is already in place to protect the electrode structure during subsequent manufacturing steps, while the through hole depth and barrier layer thickness are carefully controlled to maintain structural integrity.
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
The solution ensures high reliability by preventing Au diffusion, suppressing corrosion and disconnection, and maintaining the integrity of the semiconductor device during mounting, while also acting as a barrier layer during etching processes.
Implementation Method 1
a diffusion-suppressing layer provided on the junction layer... using a diffusion-suppressing layer to prevent Au diffusion into Au—Sn solder
Data Source
AI summary
Certain embodiments provide a semiconductor device including a semiconductor substrate, a semiconductor element, and wiring. The semiconductor element has an electrode provided on a surface of the semiconductor substrate. The electrode includes a junction layer joined to the surface of the semiconductor substrate, a diffusion-suppressing layer provided on the junction layer, and a pad layer provided on the diffusion-suppressing layer. The wiring is provided on a back surface of the semiconductor substrate and on an inner surface of a through hole which penetrates the semiconductor substrate immediately below the electrode. The wiring is electrically connected to the electrode.