Wafer Edge Electrode Layout to Block Plating Solution Ingress
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Solution Overview
Problem
Existing semiconductor manufacturing methods face challenges in effectively forming electrodes on wafer surfaces while preventing plating solution penetration and deformation of thin wafers, particularly those made of materials like SiC monocrystal, which are slow in plating reaction speed.
Innovation Solution
A wafer structure with a second electrode covering the inward portion of the second main surface to expose the peripheral edge as a plating reaction inhibiting portion, combined with a protective tape that adheres to the edge with higher adhesion than to the electrode, preventing plating solution ingress and wafer deformation during plating processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a second electrode covers the entire area of the second main surface to ensure complete coverage, then electrode coverage is improved, but plating solution can penetrate to the wafer back surface causing abnormal plating film formation
Solution Approach 1:
The patent divides the second main surface into two functional zones: a central electrode formation area and a peripheral edge area. The second electrode covers only the inward portion (central area) while intentionally exposing the peripheral edge, creating distinct functional segments that prevent plating solution penetration while maintaining electrode coverage where needed.
Solution Approach 2:
The patent applies different treatments to different regions of the wafer surface. The inward portion receives the second electrode for proper electrical connection, while the peripheral edge remains exposed to serve as a plating reaction inhibiting portion. This local differentiation resolves the contradiction between coverage and penetration prevention.
2Ease of operation
If the wafer is made thin to reduce deformation during handling, then handling ease is improved, but plating solution can penetrate through to the back surface causing abnormal plating
Solution Approach 1:
The patent preemptively prevents plating solution penetration by exposing the peripheral edge of the second main surface to act as a plating reaction inhibiting portion. This preliminary protective measure stops the plating solution before it can penetrate through thin wafers to the back surface, allowing thin wafers to be handled easily without risking abnormal plating.
3Reliability
If SiC monocrystal wafers are used for high performance, then device performance is improved, but plating reaction speed becomes too slow for efficient manufacturing
Solution Approach 1:
The patent concentrates the plating process to specific local areas (first electrode regions) rather than attempting to plate the entire wafer surface. By exposing only necessary peripheral edges and covering the rest with protective tape, the plating solution is confined to targeted areas, improving plating efficiency for SiC wafers while maintaining their high performance characteristics.
4Strength
If protective tape is adhered strongly to prevent peeling, then tape adhesion is improved, but tape may peel from the electrode surface causing plating defects
Solution Approach 1:
The patent creates different adhesion conditions for different surfaces: the protective tape adheres strongly to the peripheral edge (plating reaction inhibiting portion) to prevent peeling, while the electrode surface is designed to have lower adhesion to prevent tape peeling that would cause plating defects. This local differentiation of adhesion properties resolves the contradiction.
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 configuration enhances the reliability of semiconductor device manufacturing by preventing abnormal plating film formation and wafer deformation, ensuring high yield and quality of semiconductor devices, especially for SiC monocrystal wafers.
Implementation Method 1
a protective tape 45 adhered to the peripheral edge portion and the second electrode 24
Implementation Method 2
forming a plating film 51 on the first electrode 18 by a plating method
Data Source
AI summary
The wafer structure includes a wafer which has a first surface on one side and a second surface on the other side, a first electrode which covers the first surface, a second electrode which covers an inward portion of the second surface such as to expose a peripheral edge portion of the second surface, and a protective tape which has characteristics that an adhesion to the peripheral edge portion of the second surface is higher than an adhesion to the second electrode and which is adhered to the peripheral edge portion of the second surface and the second electrode.