SiC Layer Trench Structure for Passivation Adhesion
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Solution Overview
Problem
Integrated circuits (ICs) face stress-induced cracking during cutting operations, and existing trench structures without a silicon carbide (SiC) layer lack sufficient adhesion of passivation layers to the top metal layer, making them inadequate for withstanding manufacturing stresses.
Innovation Solution
A trench structure is formed with a silicon carbide (SiC) layer directly overlying the top metal layer, enhancing the adhesion of passivation layers, which includes dielectric materials like silicon nitride and undoped silicate glass, and recessed sidewalls to improve the structural integrity and prevent crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a trench structure is formed without a silicon carbide layer, then the manufacturing process is simpler, but the adhesion of passivation layers to the top metal layer is insufficient
Solution Approach 1:
A silicon carbide layer is introduced as an intermediary between the top metal layer and the passivation layers. This intermediate layer serves as a bonding interface that enhances adhesion between the metal and dielectric materials, preventing delamination during subsequent manufacturing steps while maintaining process feasibility.
Solution Approach 2:
The trench structure employs a composite material system consisting of multiple layers including the silicon carbide layer combined with passivation layers such as silicon nitride and undoped silicate glass. This composite structure leverages the complementary properties of each material to achieve both strong adhesion and manufacturing compatibility.
2Device complexity
If existing trench structures are used without a silicon carbide layer, then the device complexity is lower, but the stress resistance during die separation is insufficient
Solution Approach 1:
The silicon carbide layer acts as a stress buffer and intermediary structure between the metal interconnect and the overlying passivation layers. It absorbs and distributes mechanical stresses generated during die separation, preventing stress-induced cracking in the IC while adding only one additional layer to the structure.
3Productivity
If passivation layers are deposited directly on the top metal layer, then the manufacturing process has fewer steps, but crack propagation cannot be prevented
Solution Approach 1:
The silicon carbide layer serves as a critical intermediary that prevents direct contact between the metal layer and passivation layers, thereby blocking crack propagation pathways. This intermediate barrier allows the manufacturing process to remain efficient with standard deposition steps while fundamentally improving reliability by preventing stress-induced cracking.
Data Source
AI summary
A method of forming a trench structure is provided. The method includes depositing a silicon carbide (SiC) layer on a top metal layer, forming a first passivation layer on the SiC layer, removing a portion of the first passivation layer to form a first opening, forming a second passivation layer on the first passivation layer, the second passivation layer including a first portion in the first opening, and forming a second opening by removing a part of the first portion of the second passivation layer. The forming the second opening exposes the top metal layer.