Embedded Magnetic Inductor Copper Barrier Protection
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Solution Overview
Problem
Magnetic inductors in semiconductor substrate processing face significant challenges due to the leaching of magnetic materials into wet chemistries, particularly during surface finish processes, which degrades inductive performance and requires new protective measures.
Innovation Solution
The implementation of a copper barrier layer, potentially combined with a sacrificial copper feature and nickel etch stop, to shield magnetic materials from wet chemistry interactions, allowing for embedding of inductors in any substrate layer, including within the solder resist layer, thereby minimizing exposure to wet chemistries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic material is printed on inductor traces with surface finish, then inductive performance is reduced, but if surface finish is deposited after embedding magnetic material, then filler leaching is inevitable
Solution Approach 1:
A copper barrier layer is introduced as an intermediary between the magnetic material and the wet chemistry processes. This copper layer acts as a protective mediator that prevents direct contact between the magnetic filler particles and the surface finish chemistry, thereby eliminating filler leaching while preserving inductive performance. The copper barrier is deposited conformally over the magnetic material before subsequent surface finish processes.
Solution Approach 2:
The copper barrier layer is deposited in advance, before the surface finish process, to pre-establish protection against chemistry exposure. This preliminary protective action ensures that when surface finish chemistry is later applied, the magnetic material is already shielded, preventing filler leaching without compromising the inductive performance of the embedded magnetic inductor.
2Object-generated harmful factors
If magnetic material is exposed to wet chemistry processes, then filler particles leach into tanks, but if protective measures are implemented, then process complexity increases
Solution Approach 1:
The copper barrier layer serves as a simple yet effective intermediary that prevents filler leaching without requiring complex process changes. This single protective layer eliminates the need for multiple complex protective measures while effectively preventing magnetic material exposure to wet chemistry processes throughout subsequent manufacturing steps.
3Reliability
If copper barrier layer is used to protect magnetic material, then exposure to wet chemistries is eliminated, but manufacturing complexity increases
Solution Approach 1:
The copper barrier layer serves multiple functions simultaneously: it acts as a protective barrier against wet chemistry exposure, provides an etch stop layer for subsequent processing, and serves as a conductive layer that can be patterned to form electrical connections. This multi-functionality reduces the need for separate protective layers and simplifies the overall manufacturing process despite the added protection.
Solution Approach 2:
The copper barrier layer's properties are optimized to change state during processing - it is deposited as a protective barrier, then selectively removed via laser ablation or flash etch in specific areas to create connections. This parameter change capability allows the same layer to provide both protection and connectivity functions without requiring additional manufacturing steps.
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 effectively eliminates or significantly reduces the exposure of magnetic inductors to wet chemistries, enhancing their performance and integrity by using a copper barrier to protect the magnetic materials during processing.
Implementation Method 1
The implementation of a copper barrier layer, potentially combined with a sacrificial copper feature and nickel etch stop, to shield magnetic materials from wet chemistry interactions
Implementation Method 2
sacrificial copper feature and nickel etch stop, to shield magnetic materials from wet chemistry interactions
Data Source
AI summary
An apparatus and method of forming a magnetic inductor circuit. A substrate is provided and a first magnetic layer is formed in contact with one layer of the substrate. A conductive trace is formed in contact with the first magnetic layer. A sacrificial cooper layer protects the magnetic material from wet chemistry process steps. A conductive connection is formed from the conductive trace to the outside substrate, the conductive connection comprising a horizontal connection formed by in-layer plating. A second magnetic layer is formed in contact with the conductive trace. Instead of a horizontal connection, a vertical conductive connection can be formed that is perpendicular to the magnetic layers, by drilling a first via in a second of the magnetic layers, forming a buildup layer, and drilling a second via through the buildup layer, where the buildup layer protects the magnetic layers from wet chemistry processes.