Polyimide Bump Structure for Low-k Delamination Resistance
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Solution Overview
Problem
Delamination of extreme low-k dielectric layers in semiconductor devices leads to device failure and malfunction, particularly in smaller devices with three-dimensional integrated circuits, due to the processing and reliability issues of bumps used for interconnects.
Innovation Solution
The use of polyimide layers with higher Young's modulus, formed from specific dianhydride and diamine reactants, to create a buffer layer that enhances adhesion and protects the device from damage during flip chip bonding, combined with under bump metallization and solder layers to ensure reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bump structures are used for interconnects in three-dimensional integrated circuits, then device integration and connectivity are improved, but delamination of extreme low-k dielectric layers occurs leading to device failure
Solution Approach 1:
A buffer layer is formed between the bump structure and the extreme low-k dielectric layer to prevent delamination. This buffer layer absorbs and distributes the stress and pressure generated during flip chip bonding and device operation, cushioning the dielectric layer against damage before delamination can occur.
Solution Approach 2:
The buffer layer acts as an intermediary element between the bump structure and the extreme low-k dielectric layer. It mediates the mechanical stress and adhesion forces, providing a transition zone that prevents direct contact between the bump and the vulnerable dielectric layer, thereby eliminating the delamination issue.
2Strength
If polyimide layers with higher Young's modulus are used to prevent delamination, then adhesion and structural integrity are improved, but device complexity increases
Solution Approach 1:
The Young's modulus of the polyimide buffer layer is specifically optimized to a higher range to enhance adhesion strength and structural integrity. By adjusting this material parameter, the buffer layer can effectively withstand bonding pressures and prevent delamination while maintaining a relatively simple overall device structure.
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 polyimide layers improve the structural integrity of semiconductor devices by distributing pressure and preventing delamination, ensuring reliable electrical connections and device functionality.
Implementation Method 1
The polyimide layer is adhered to the passivation layer and the metal pad structure
Data Source
AI summary
A method of manufacturing a bump structure includes forming a passivation layer over a substrate. A metal pad structure is formed over the substrate, wherein the passivation layer surrounds the metal pad structure. A polyimide layer including a polyimide is formed over the passivation layer and the metal pad structure. A metal bump is formed over the metal pad structure and the polyimide layer. The polyimide is a reaction product of a dianhydride and a diamine, wherein at least one of the dianhydride and the diamine comprises one selected from the group consisting of a cycloalkane, a fused ring, a bicycloalkane, a tricycloalkane, a bicycloalkene, a tricycloalkene, a spiroalkane, and a heterocyclic ring.