Thick Copper Feature Formation Using Laser and Water Jet
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Solution Overview
Problem
Existing methods struggle to efficiently form features in thick copper layers greater than 1 mm, as conventional etching techniques require significant material removal, posing challenges in mechanical stability and processing efficiency.
Innovation Solution
A method involving a copper layer thicker than 1 mm, where a trench is partially cut using a laser, and the remaining thickness is removed using a water jet, followed by etching. This method can include coupling the copper layer with a dielectric substrate, such as aluminum oxide or boron nitride, and forming additional layers or heat sinks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching techniques are used to form features in thick copper layers, then complete material removal is achieved, but mechanical stability deteriorates and processing efficiency decreases
Solution Approach 1:
The patent divides the single etching process into multiple stages: first performing a partial etch to create a trench, then removing the copper layer in sections using water jet or laser, and finally completing the etch. This segmentation allows the process to handle thick copper layers more efficiently while maintaining mechanical stability throughout the process.
Solution Approach 2:
The patent applies preliminary actions by first forming a protective layer over the copper layer before etching, and performing a first etch to create a trench structure. These preliminary steps prepare the copper layer for subsequent water jet or laser processing, ensuring that the thick copper can be removed efficiently without compromising structural integrity.
2Manufacturing precision
If conventional etching techniques are used to form features in thick copper layers, then complete material removal is achieved, but mechanical stability deteriorates
Solution Approach 1:
The patent segments the copper removal process into distinct phases: initial etching to create a trench, intermediate water jet or laser processing to remove bulk material, and final etching to complete feature formation. This segmentation prevents excessive material removal at any single stage, maintaining mechanical stability throughout.
Solution Approach 2:
The patent applies beforehand cushioning by forming a protective layer over the copper layer prior to etching. This protective layer acts as a cushion that prevents damage to the copper structure during the etching process and allows for controlled material removal while preserving mechanical stability.
3Reliability
If thicker copper layers are used, then electrical performance and heat dissipation are improved, but feature formation difficulty increases
Solution Approach 1:
The patent segments the feature formation process into multiple steps including partial etching, water jet or laser processing, and completion etching. This segmentation makes it feasible to process thick copper layers that would be difficult to etch completely in a single step, thereby maintaining electrical performance while improving manufacturability.
Solution Approach 2:
The patent introduces water jet or laser processing as an intermediary method between conventional etching steps. This intermediary approach enables effective material removal from thick copper layers without relying solely on chemical etching, making the manufacturing process more manageable while preserving the electrical performance benefits of thick copper.
4Temperature
If thicker copper layers are used, then heat dissipation is improved, but processing complexity increases
Solution Approach 1:
The patent segments the processing into distinct stages: protective layer formation, partial etching, water jet or laser processing, and completion etching. This segmentation breaks down the complex task of processing thick copper into manageable steps, reducing overall processing complexity while maintaining the heat dissipation advantages of thick copper layers.
Solution Approach 2:
The patent uses water jet or laser processing as an intermediary technique to simplify the overall process. This intermediary method efficiently handles the bulk material removal from thick copper layers, reducing the complexity burden that would otherwise be placed on conventional etching processes alone.
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
This method effectively forms copper features in thick copper layers, improving mechanical stability and processing efficiency by allowing for the formation of features with tighter pitches and reduced risk of bridging or shorting defects.
Implementation Method 1
cutting a trench partially through the thickness leaving a remaining thickness using a laser
Implementation Method 2
after cutting, removing the remaining thickness using a water jet
Implementation Method 3
reducing copper oxide in the copper layer by exposing the copper layer to a forming gas
Data Source
AI summary
Implementations of a method of forming a copper feature may include providing a copper layer with a thickness thicker than 1 mm; cutting a trench partially through the thickness leaving a remaining thickness using a laser; and, after cutting, removing the remaining thickness using a water jet.