Low Z-Height Package Assembly With Barrier Layer Protection
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Solution Overview
Problem
The miniaturization of package assemblies poses a challenge in creating components with reduced layer count and z-height, as etching or roughening conductive traces to enhance solder resist bonding can inadvertently damage the underlying die, leading to component failure.
Innovation Solution
A barrier layer is deposited over the package assembly to protect the die and traces during etching or roughening processes, allowing for the formation of chemically roughened pads that securely adhere a solder resist layer without damaging the underlying components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the conductive traces or pads are chemically etched or roughened to enhance solder resist bonding, then the adhesion strength is improved, but the underlying die is damaged leading to component failure
Solution Approach 1:
A barrier layer is introduced as an intermediary between the conductive traces/pads and the die. This barrier layer is selectively removed only in the trace regions (not pad regions) before applying the solder resist, allowing the solder resist to bond to the roughened trace surfaces without exposing the die to damaging etchants. The barrier layer thus mediates the conflict between needing trace roughening for adhesion and protecting the die from damage.
Solution Approach 2:
The barrier layer is selectively removed only in specific locations (trace regions) while being retained in other locations (pad regions). This local differentiation allows the solder resist to achieve strong bonding on the roughened traces while the die remains protected in areas where the barrier layer is retained, resolving the contradiction through spatially varying properties.
2Volume of moving object
If the layer count and z-height are reduced to achieve miniaturization, then the package size is reduced, but the manufacturing complexity increases
Solution Approach 1:
The barrier layer is deposited over the entire surface before any etching or roughening operations. This preliminary action establishes a protective framework that simplifies subsequent manufacturing steps by defining exactly where etching should occur (where the barrier is removed) and where it should not (where the barrier remains), thereby reducing manufacturing complexity despite the reduced layer count.
Solution Approach 2:
The barrier layer is selectively removed in segmented fashion - removed from trace regions but retained over pad regions. This segmentation allows different areas to undergo different treatments, enabling the solder resist to bond properly to traces while protecting pads and die, thus achieving miniaturization without proportionally increasing manufacturing complexity.
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 creation of package assemblies with reduced layer count and z-height by ensuring strong solder resist adhesion while protecting the die and traces from etching or roughening, thereby preventing component failure.
Implementation Method 1
A barrier layer is deposited over the package assembly to protect the die and traces during etching or roughening processes
Implementation Method 2
it may be desirable for the traces or pads to be chemically etched or roughened
Data Source
AI summary
In embodiments, a package assembly may include a die coupled with one or more conductive pads. A barrier layer may be directly coupled with and between the die and one or more of the conductive pads. The package assembly may further include a solder resist layer coupled with the die and the conductive pads, and one or more interconnects positioned at least partially within the solder resist layer and directly coupled with one or more of the conductive pads.