Metal Stud Bumps for Thin Package on Package Devices
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Solution Overview
Problem
The semiconductor industry faces limitations in reducing the total thickness of package on package (PoP) devices due to the height of solder ball joints between top and bottom packages, which hinders further integration density and miniaturization of electronic components.
Innovation Solution
The implementation of novel metal stud bumps with a stick region and a ball region, formed using a wire-bonding method, which are used to connect the first and second packaged dies, allowing for a reduced distance between them and enabling thinner PoP devices by embedding the metal stud bumps within solder joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder ball joints are used to connect top and bottom packages in PoP devices, then reliable electrical connection is achieved, but the total thickness of the PoP device increases due to the height of the solder ball joints
Solution Approach 1:
The connection structure is segmented into two parts: a flat metal stud bump that provides mechanical support and positioning, and a separate solder joint that provides electrical connection. This segmentation allows the metal stud bump to be extremely thin (reducing overall thickness) while the solder joint maintains reliable electrical connection without adding significant height, as it can be embedded or flush-mounted.
Solution Approach 2:
The metal stud bump acts as an intermediary element between the top and bottom packages. It provides a flat, thin interface that enables the solder joint to be formed with minimal height addition, thereby mediating between the requirement for reliable electrical connection and the need to minimize total device thickness.
2Ease of manufacture
If traditional packaging methods are used, then ease of manufacture is maintained, but integration density and miniaturization of electronic components are limited
Solution Approach 1:
The metal stud bump formation process merges wire bonding technology with bump formation, combining two functions into a single manufacturing step. This integration maintains ease of manufacture by using existing wire bonding equipment and processes, while achieving the miniaturization goals through the thin-profile metal stud structure that enables higher integration density.
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 results in PoP devices with a total thickness of about 1 mm or less, achieving a 10% or greater reduction in thickness, while also providing low-profile, high-yield, and cost-effective packaging solutions for semiconductor devices.
Implementation Method 1
The implementation of novel metal stud bumps with a stick region and a ball region, formed using a wire-bonding method
Data Source
AI summary
Package on package (PoP) devices and methods of packaging semiconductor dies are disclosed. A PoP device includes a first packaged die and a second packaged die coupled to the first packaged die. Metal stud bumps are disposed between the first packaged die and the second packaged die. The metal stud bumps include a stick region, a first ball region coupled to a first end of the stick region, and a second ball region coupled to a second end of the stick region. The metal stud bumps include a portion that is partially embedded in a solder joint.