Through Package Via Solder Reflow Height Control
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Solution Overview
Problem
Conventional copper via plating techniques in 3D IC packaging result in height variations, leading to yield loss and high manufacturing costs due to the expensive deposition of substantial copper amounts.
Innovation Solution
The use of through package vias (TPVs) with a metal pad over a build-up film layer, a polymer ring, and a solder feature electrically coupled through a reflow process, which reduces manufacturing costs and prevents height variations by forming a stable and cost-effective intermetallic compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copper via plating techniques are used, then electrical connectivity is achieved, but height variations occur leading to yield loss and high manufacturing costs
Solution Approach 1:
The patent changes the material parameter from copper to solder, and changes the formation process parameter from electroplating to reflow soldering. This transforms the via formation from a deposition process prone to height variations into a melting and reflow process that produces uniform, consistent heights, thereby resolving the manufacturing precision issue while maintaining electrical connectivity
Solution Approach 2:
The patent replaces expensive copper material with cheaper solder material. The solder via structures are formed through a cost-effective reflow process rather than expensive copper deposition, directly addressing the high manufacturing costs associated with conventional copper via plating techniques
2Reliability
If substantial amounts of copper are deposited, then electrical connectivity is achieved, but manufacturing costs increase due to expensive deposition processes
Solution Approach 1:
The patent substitutes expensive copper with inexpensive solder material. The reflow soldering process used to form the vias is significantly cheaper than electroplating or other copper deposition methods, directly reducing manufacturing costs while achieving the same electrical connectivity function
Solution Approach 2:
The patent changes both the material parameter (copper to solder) and the process parameter (deposition to reflow). This dual parameter change transforms an expensive manufacturing process into a cost-effective one, resolving the contradiction between electrical connectivity and manufacturing costs
3Reliability
If edge wiring is used in 3D packages, then electrical connectivity is achieved, but package size increases
Solution Approach 1:
The patent transitions from planar edge wiring to vertical through-package vias. By routing connections through the thickness dimension of the package rather than along the perimeter, the design enables more compact layouts and smaller overall package size while maintaining all necessary electrical connectivity paths
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
TPVs minimize yield loss and reduce manufacturing costs by eliminating height variations and utilizing less expensive materials, while enabling efficient electrical coupling and miniaturization of IC packages.
Implementation Method 1
a solder feature electrically coupled with the metal pad through a reflow process
Data Source
AI summary
A through package vias (TPV), a package including a plurality of the TPVs, and a method of forming the through package via are provided. Embodiments of a through package via (TPV) for a package include a build-up film layer, a metal pad disposed over the build-up film layer, a polymer ring disposed over the metal pad, and a solder feature electrically coupled with the metal pad.