Selective Electrolytic Via Plating Using Temporary Bonding
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Solution Overview
Problem
The existing method of applying an electrically conductive material to through-vias using electrolytic plating is time-consuming and expensive due to the need to plate all surfaces of the interposer substrate, resulting in an overburden layer that requires removal.
Innovation Solution
A method involving a temporary bond between a carrier substrate and an interposer using a surface modification layer, allowing for selective electrolytic plating of through-vias without plating the entire substrate, thereby eliminating the need for removing an overburden layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrolytic plating is applied to all surfaces of the interposer substrate including planar surfaces, then through-vias can be filled with conductive material, but an overburden layer is formed on planar surfaces requiring additional removal steps
Solution Approach 1:
The substrate surface is segmented into through-via regions and planar surface regions, with selective plating applied only to through-via regions using a mask layer to prevent plating on planar surfaces
Solution Approach 2:
A mask layer is introduced as an intermediary element to selectively block plating current on planar surfaces while allowing plating in through-via regions, preventing overburden formation
2Manufacturing precision
If electrolytic plating is applied to all surfaces of the interposer substrate, then through-vias can be filled with conductive material, but processing time increases due to overburden removal
Solution Approach 1:
The unnecessary plating step on planar surfaces is extracted and eliminated from the process by using a mask layer to prevent plating in those regions, reducing total processing time
Solution Approach 2:
Instead of applying plating to all surfaces (excessive action), plating is applied only to the necessary through-via regions (partial action), eliminating wasted processing time on planar surfaces
3Manufacturing precision
If electrolytic plating is applied to all surfaces of the interposer substrate, then through-vias can be filled with conductive material, but manufacturing cost increases due to additional materials and process steps
Solution Approach 1:
A disposable mask layer is used to prevent plating on planar surfaces during the plating process, eliminating the need for expensive overburden removal steps and reducing overall manufacturing cost
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 reduces processing time and costs by enabling the filling of through-vias with conductive material without forming an overburden layer, allowing for efficient electrical conduction through the interposer.
Implementation Method 1
a surface modification layer, allowing for selective electrolytic plating of through-vias
Implementation Method 2
The conductive material can be applied to the through-via by electrolytical plating
Implementation Method 3
exposing the surface modification layer to an oxygen plasma
Data Source
Figure 1A~1D
Figure 2A~2D
Figure 3A~3C
AI summary
Disclosed herein is a bottom-up electrolytic via plating method wherein a first carrier substrate (100) and a second substrate (110) having at least one through-via (120) are temporarily bonded together. The method includes applying a seed layer (108) on a surface of the first substrate, forming a surface modification layer (114) on the seed layer or the second substrate, bonding the second substrate to the first substrate with the surface modification layer to create an assembly wherein the seed layer and the surface modification layer are disposed between the first and second substrates, applying conductive material (122) to the through-via, removing the second substrate having the through-via containing conductive material from the assembly.