Through-Via Metal Wiring Using Foil Seed Layers Instead of Sputtering
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Solution Overview
Problem
Conventional methods for forming through-via metal wiring on glass substrates require expensive sputtering processes and can result in defects like voids or seams, affecting electrical characteristics and reliability.
Innovation Solution
A method involving bonding a metal foil to a substrate with an adhesive layer, plasma treatment to remove the adhesive inside the via hole, followed by metal filling through electrolytic plating, and subsequent removal of the foil and adhesive using an etchant, eliminating the need for sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sputtering process is used to form metal layers, then adhesion and coverage are improved, but manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent replaces expensive sputtering processes with a disposable copper foil that is bonded to the substrate and then removed after serving as a temporary seed layer. This eliminates the need for costly sputtering equipment and materials while achieving the same functional result of providing a conductive base for plating.
Solution Approach 2:
The patent extracts and removes the expensive sputtering process from the manufacturing sequence entirely. Instead of depositing metal layers through sputtering, the method uses a copper foil that is bonded, used as a seed layer, and then completely removed after plating, leaving only the desired metal wiring structure.
2Reliability
If sputtering process is used to form metal layers, then adhesion and coverage are improved, but process complexity increases
Solution Approach 1:
The copper foil serves as a temporary, disposable seed layer that simplifies the overall process. It provides the necessary conductive base for plating without requiring complex sputtering equipment or multi-step deposition processes, and is easily removed after serving its purpose.
Solution Approach 2:
The patent changes the physical state and form of the seed layer from a deposited thin film (sputtering) to a bonded foil that is subsequently removed. This parameter change in the approach to creating the seed layer simplifies the process while maintaining the essential function of providing a conductive base for plating.
3Ease of manufacture
If conventional plating is performed without proper seed layer preparation, then process simplicity is maintained, but plating quality deteriorates with gap defects and boundary defects
Solution Approach 1:
The copper foil provides an excellent, ready-made seed layer surface that ensures high-quality plating without the need for complex sputtering preparation. The foil's surface properties promote uniform metal deposition, and its removal leaves clean, defect-free via holes with no gap defects or boundary seams.
Solution Approach 2:
The copper foil is bonded and prepared in advance before plating, creating an ideal seed layer surface that ensures uniform metal deposition. This preliminary preparation of the seed layer through foil bonding and plasma treatment prevents plating defects without adding complex steps during the actual plating process.
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 approach enables the formation of through-via metal wiring with excellent plating quality and reduced defects, achieving reliable electrical connections without the expense of sputtering processes.
Implementation Method 1
bonding a metal foil to one side of a substrate having a through-via formed therein with an adhesive layer
Implementation Method 2
treating a hole formed by the through-via and the metal foil with a plasma to remove the adhesive layer located inside the hole
Implementation Method 3
filling the hole with metal by a plating process
Implementation Method 4
filling the hole with metal by a plating process
Implementation Method 5
removing the metal foil and the adhesive layer with an etchant
Data Source
Figure 1(a)~1(e)
Figure 2(a)~2(e)
Figure 3A~3B
AI summary
The present invention relates to a method for forming through-via metal wiring, and according to the method of the present invention, through-via metal wiring can be formed with excellent plating quality without an expensive sputtering process by bonding a metal foil to one side of a substrate having a through-via formed therein and using the foil as a metal seed layer.