Penetrating Wire Electrolytic Plating via Seed Layer Exposure
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Solution Overview
Problem
Existing methods for manufacturing penetrating wire substrates face challenges such as residue formation during bonding layer removal, difficulty in controlling lateral spread, and high resistance issues with polycrystalline silicon, leading to inefficiencies in miniaturization and increased costs.
Innovation Solution
A method involving a substrate with a through hole, an electroconductive seed layer, and a wall part linked to the hole, where the bonding layer is removed to expose the seed layer, allowing for electrolytic plating to fill the hole and suppress lateral conductor spread, enabling high-density element and penetrating wire arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bonding layer is removed by over etching to expose the seed layer, then the seed layer can be exposed for conductor formation, but the bonding layer residue cannot be completely removed and lateral spread control becomes difficult
Solution Approach 1:
The patent divides the removal process into two distinct stages: first removing the bonding layer from the wall part surface, then removing the bonding layer from the through hole interior. This segmentation allows each removal operation to be optimized independently, preventing residue while controlling lateral spread.
Solution Approach 2:
The patent performs preliminary removal of the bonding layer from the wall part before removing it from the through hole. This preliminary action prepares the surface for subsequent conductor material deposition while preventing uncontrolled lateral spread that would occur with aggressive over-etching.
2Ease of manufacture
If polycrystalline silicon is used for the penetrating wire, then the manufacturing process is simplified, but the resistance becomes too high
Solution Approach 1:
The patent changes the material parameter from polycrystalline silicon to copper for the penetrating wire conductor. This material substitution dramatically reduces electrical resistance while the electrolytic plating process ensures complete filling of the through hole, achieving both low resistance and manufacturing feasibility.
3Reliability
If copper is used for the conductor material, then the resistance is lowered, but the number of polishing steps increases and cost may increase
Solution Approach 1:
The patent extracts the conductor material deposition step from the traditional planarization process by using electrolytic plating to fill the through hole. This eliminates the need for multiple polishing steps to achieve flat surfaces, as the plating process naturally fills the hole without requiring subsequent mechanical removal of excess material.
Solution Approach 2:
The patent replaces the mechanical polishing system with an electrolytic plating system. Instead of using mechanical abrasion to create flat surfaces and fill holes, the electrolytic process uses electrochemical deposition to precisely fill the through hole with copper, eliminating complex mechanical polishing operations.
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 allows for the efficient formation of penetrating wires with reduced lateral spread and lower resistance, facilitating miniaturization and high-density arrangement of elements, while minimizing costs by using copper for conductor material.
Implementation Method 1
filling the inside of the wall part and the through hole with a conductor, by using the seed layer through electrolytic plating
Data Source
AI summary
According to a method for manufacturing a device in which an electrode of an element is electrically connected to a penetrating wire in a substrate, a structure is prepared in which the element is arranged on the first substrate having a through hole formed therein: and a second substrate is prepared which has an electroconductive seed layer formed thereon. Then, a wall part is formed on the first substrate; a seed layer is joined to a face on an element side of the structure through a bonding layer; the bonding layer is removed; and the seed layer is exposed in the inside of the opening. The inside of the wall part and the through hole is filled with a conductor, with the use of the seed layer through electrolytic plating.