Polyimide Bump Structure With Modulus-Tuned Delamination Buffer
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Solution Overview
Problem
The delamination of extreme low-k dielectric layers in semiconductor devices, particularly in smaller devices, leads to device failure or malfunction, as the processing and reliability of bumps used for interconnecting stacked chips are compromised.
Innovation Solution
The implementation of a polyimide layer with a specific Young's modulus range of 4.5 GPa to 7 GPa, formed through a polyamic acid composition derived from dianhydride and diamine reactants, is used to enhance the adhesion and mechanical properties of bump structures, preventing delamination and ensuring device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bump structures are used to interconnect stacked chips, then device integration and performance are improved, but delamination of extreme low-k dielectric layers occurs leading to device failure
Solution Approach 1:
A polyimide layer is introduced as an intermediary between the bump structure and the extreme low-k dielectric layer. This polyimide layer acts as a buffer that absorbs mechanical stress and prevents direct stress transfer to the dielectric layer, thereby preventing delamination while maintaining the bump interconnection function
Solution Approach 2:
The patent uses a composite structure combining polyimide material with specific mechanical properties (Young's modulus of 2-4 GPa) integrated with the dielectric layers. This composite approach creates a multi-layer structure where each material contributes its specific properties: the polyimide provides stress buffering while the dielectric layers provide electrical isolation
2Volume of moving object
If device size is decreased to meet consumer demand, then device compactness is improved, but delamination of dielectric layers in bump regions becomes more severe
Solution Approach 1:
The patent changes the mechanical parameter (Young's modulus) of the polyimide layer to a specific range (2-4 GPa) that is optimized for stress distribution. This parameter optimization allows the polyimide layer to effectively buffer stress in miniaturized devices where stress concentration is more severe, preventing delamination despite reduced device size
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 layer effectively prevents delamination of the polyimide from underlying passivation layers, providing improved protection and maintaining device integrity even under high pressure, thus enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
A polyimide layer including a polyimide is formed over the passivation layer and the metal pad structure... the polyimide layer effectively prevents delamination of the polyimide from underlying passivation layers, providing improved protection and maintaining device integrity even under high pressure
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.