Package Openings With Scalloped Sidewalls for Reliable PoP Contacts
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Solution Overview
Problem
The challenge in semiconductor packaging is forming openings with critical dimensions that allow for reliable electrical connections between stacked package structures, as existing methods result in distorted and non-smooth edges, affecting the integrity of the connections.
Innovation Solution
A manufacturing method involving laser drilling followed by an etching process to form openings in the dielectric layer, which smooths the sidewalls and increases the included angle to over 60 degrees, ensuring a larger critical dimension and improved edge profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional opening formation methods are used, then manufacturing process is simple, but opening edges are distorted and non-smooth affecting connection integrity
Solution Approach 1:
The opening formation process is divided into two distinct stages: laser drilling to create the initial opening, followed by etching to smooth the sidewalls. This segmentation allows each process to optimize for its specific function, achieving smooth edges without requiring a completely new monolithic process
Solution Approach 2:
The etching process acts as an intermediary step between laser drilling and final connector formation. This intermediate etching step modifies the laser-drilled opening by smoothing sidewalls and increasing the included angle, thereby improving connection integrity without directly altering the laser drilling parameters
2Reliability
If opening critical dimension is increased, then electrical connection reliability is improved, but manufacturing precision control becomes more difficult
Solution Approach 1:
The conventional mechanical drilling method is replaced with laser drilling followed by chemical etching. This substitution enables better control over the opening's included angle and critical dimension, as the etching process can be precisely controlled to achieve the desired geometry while maintaining reliability
3Productivity
If laser drilling is used to form openings, then manufacturing speed is improved, but opening sidewalls become rough and distorted
Solution Approach 1:
Two processes—laser drilling and etching—are merged into a sequential workflow where laser drilling provides high-speed opening formation and etching provides sidewall smoothing. This combination maintains the productivity benefits of laser drilling while eliminating its drawback of rough sidewalls
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
The method results in openings with a smooth edge and larger critical dimension, facilitating better electrical contact and reliability in package-on-package devices without significantly altering manufacturing steps or costs.
Implementation Method 1
forming openings for connectors plays a critical role
Implementation Method 2
an etching process to form openings in the dielectric layer, which smooths the sidewalls and increases the included angle to over 60 degrees
Data Source
AI summary
Device, package structure and method of forming the same are disclosed. The device includes a die encapsulated by an encapsulant, a conductive structure aside the die, and a dielectric layer overlying the conductive structure. The conductive structure includes a through via in the encapsulant, a redistribution line layer overlying the through via, and a seed layer overlying the redistribution line layer. The dielectric layer includes an opening, wherein the opening exposes a surface of the conductive structure, the opening has a scallop sidewall, and an included angle between a bottom surface of the dielectric layer and a sidewall of the opening is larger than about 60 degrees.