Contact Pad Halogen Removal via Water Vapor Plasma
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Solution Overview
Problem
Current pad treatment processes for semiconductor devices often result in halogen-contaminated contact pads, leading to issues like discoloration, rough surfaces, and degraded electrical contact resistance, which can cause non-conformances and yield loss during further processing steps such as wafer thinning and bonding.
Innovation Solution
A thermally activated atmosphere containing water or reactive components of water is used to reduce halogen contamination on contact pads, forming a pad surface passivation layer of aluminum oxide, which helps in removing fluorine contaminants and improving surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pad treatment processes are used, then pad surface treatment is achieved, but halogen contamination occurs leading to discoloration and rough surfaces
Solution Approach 1:
The patent converts the harmful halogen contamination into a beneficial effect by using plasma treatment to remove the halogen contaminants and simultaneously form a controlled aluminum oxide passivation layer. The harmful fluorine contamination is transformed into a removable state through plasma exposure, while the desired aluminum oxide layer is formed to protect the pad surface.
Solution Approach 2:
The patent employs plasma treatment with oxygen or oxygen-containing gases to accelerate the oxidation of aluminum on the pad surface, forming a controlled aluminum oxide passivation layer. This strong oxidizing environment enables rapid and uniform formation of the protective oxide layer without requiring high temperatures.
2Ease of operation
If halogen-containing etchants are used for passivation layer etching, then pad opening is achieved, but fluorine contamination degrades electrical contact resistance
Solution Approach 1:
The patent extracts and removes the harmful fluorine contamination from the pad surface using plasma treatment. The plasma process selectively removes the halogen contaminants deposited during the etching process, separating the beneficial pad opening function from the harmful contamination effect.
Solution Approach 2:
The patent introduces plasma treatment as an intermediary process between the halogen-containing etching step and subsequent processing. This intermediate plasma treatment step acts as a mediator that removes the harmful fluorine contamination while preserving the pad opening achieved by the etching process.
3Device complexity
If pad surfaces are not properly treated, then processing is simplified, but corrosion resistance and adhesion are compromised
Solution Approach 1:
The patent applies preliminary plasma treatment and aluminum oxide formation before subsequent processing steps such as wafer thinning and bonding. This preliminary action prepares the pad surface in advance, ensuring corrosion resistance and proper adhesion properties are established before the device undergoes further processing.
Solution Approach 2:
The patent changes the surface parameters of the pad by forming an aluminum oxide passivation layer through plasma treatment. This parameter change transforms the surface chemistry and morphology, providing enhanced corrosion resistance and controlled adhesion properties without significantly increasing process complexity.
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 process effectively reduces fluorine contamination by at least 50% and forms a stable aluminum oxide passivation layer, enhancing the pad surface's resistance to corrosion and maintaining low surface roughness, thus ensuring better adhesion and reducing post-processing residues.
Implementation Method 1
subjecting the contact pad to a thermally activated atmosphere containing water or reactive components of water, such that the halogen contamination of the exposed part of the topmost layer of the contact pad is reduced
Implementation Method 2
forming a pad surface passivation layer of aluminum oxide by subjecting the contact pad to a thermally activated atmosphere containing water or reactive components of water
Implementation Method 3
subjecting the contact pad to a thermally activated atmosphere containing water or reactive components of water, such that the halogen contamination of the exposed part of the topmost layer of the contact pad is reduced
Data Source
AI summary
In various embodiments, a method of processing a contact pad may include providing a contact pad, a topmost layer of the contact pad containing aluminum or an aluminum alloy, at least part of the topmost layer of the contact pad being exposed; subjecting the contact pad to a thermally activated atmosphere containing water or reactive components of water.