NBLoK Layer Seals Bond Pad Passivation End Portions
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Solution Overview
Problem
Fluorine contamination from plasma etching processes in semiconductor device fabrication leads to corrosion and performance degradation of bond pad surfaces, particularly in aluminum bond pads, due to residual fluorine polymers, resulting in higher failure rates and reduced adhesion of bonding wires or solder bumps.
Innovation Solution
A method involving the deposition of a nitrogen-doped barrier low-k (NBLoK) layer over the end portions of the passivation layer to seal and protect the bond pad surfaces from further contamination, using dielectric materials like silicon carbonitride, silicon oxynitride, or silicon nitride, which are conformally applied and then anisotropically removed to form protective caps, preventing fluorine polymer discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching process is used to form bond pad openings in passivation layer, then bond pad openings are formed, but fluorine contamination occurs on bond pad surfaces
Solution Approach 1:
A nitrogen-doped barrier low-k (NBLoK) layer is introduced as an intermediary between the plasma etching process and the bond pad surface. This NBLoK layer acts as a protective barrier that prevents fluorine polymers from the etching process from directly contaminating the bond pad surface, while still allowing the etching process to proceed and form the necessary bond pad openings.
Solution Approach 2:
The patent modifies the chemical composition parameters of the passivation layer by incorporating nitrogen-doped low-k material. This parameter change alters the layer's properties to provide barrier functionality against fluorine contamination, transforming it from a simple insulating layer to a protective barrier layer that resists fluorine polymer adhesion.
2Reliability
If fluorine polymers remain on passivation layer end portions, then adhesion-like contaminants are formed, but fluorine contaminants discharge and corrode bond pad surfaces over time
Solution Approach 1:
The NBLoK layer is applied in advance to the passivation layer end portions before any fluorine contamination can occur. This preliminary protective action ensures that when plasma etching is performed later, the fluorine polymers cannot discharge contaminants onto the bond pad surface, preventing corrosion before it starts.
Solution Approach 2:
The patent converts the potentially harmful fluorine polymers generated during plasma etching into a beneficial situation by using the NBLoK layer to contain them. The fluorine polymers that would normally contaminate the bond pad are instead confined to the NBLoK layer, where they cannot cause harm, thus converting a harmful byproduct into a contained, non-threatening element.
3Reliability
If bond pad surfaces are exposed to fluorine contaminants, then corrosion and performance degradation occur, but adhesion of bonding wires or solder bumps is reduced
Solution Approach 1:
The NBLoK layer serves as a protective intermediary that shields the bond pad surface from fluorine contaminants. By placing this barrier layer between the contaminant source and the bond pad, it prevents both corrosion and adhesion degradation, maintaining the bond pad's performance and bonding strength.
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 NBLoK layer effectively reduces contamination and enhances bond pad reliability by preventing fluorine polymer discharge, thereby improving the adhesion of bonding wires or solder bumps and reducing the failure rate of semiconductor devices.
Implementation Method 1
A method involves depositing a nitrogen-doped barrier low-k (NBLoK) layer over the end portions of a passivation layer
Implementation Method 2
The plasma etching process is typically performed in a fluorine-containing gases environment; for example, hydrofluorocarbon (CHF3)
Data Source
AI summary
According to an aspect of the present disclosure, a semiconductor device is provided that includes a substrate, at least one bond pad, a passivation layer and a NBLoK layer. The bond pad is formed over the substrate. The passivation layer is deposited over the substrate and has an opening defined by end portions of the passivation layer over the bond pad. The NBLoK layer is covering the end portions of the passivation layer.