Stackable Semiconductor Package Ultrasonic Stud Bump Bonding
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Solution Overview
Problem
Conventional semiconductor packages experience deformation due to high temperatures during the reflow process, leading to a deformed stacked semiconductor structure.
Innovation Solution
A semiconductor package with a stud bump formed by wire bonding technology, allowing bonding without a reflow process, which reduces deformation by using ultrasonic bonding technology and a pad protection layer for enhanced bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflow process is applied to semiconductor packages to form solder balls and connect stacked packages, then electrical connection between packages is achieved, but high temperatures during the reflow process cause warpage and deformation of the semiconductor packages
Solution Approach 1:
The patent changes the bonding method from thermal reflow process to ultrasonic bonding process. This parameter change eliminates the need for high temperature heating, thereby preventing warpage and deformation of semiconductor packages while still achieving reliable electrical connection between stacked packages through the stud bump and solder ball assembly
Solution Approach 2:
The patent replaces the thermal field (reflow process) with a mechanical field (ultrasonic bonding). The ultrasonic bonding process uses mechanical vibration energy to create metallurgical bonds between the stud bump and the pad, eliminating thermal stress that causes package deformation while maintaining electrical connectivity
2Reliability
If the reflow process is applied multiple times during stacking, then electrical connections are established between multiple packages, but cumulative deformation increases in the stacked semiconductor structure
Solution Approach 1:
The patent performs preliminary action by forming the stud bump on the lower package before stacking. This pre-formed protruding structure enables direct ultrasonic bonding without requiring subsequent reflow processes during stacking operations, thereby preventing cumulative deformation while establishing electrical connections between multiple packages in the stack
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 solution effectively reduces deformation in semiconductor packages by eliminating the need for high-temperature reflow processes and enhancing bonding strength through ultrasonic bonding and pad protection layers.
Implementation Method 1
the stud bump allows bonding to another semiconductor package or device. Since the process of bonding to the stud bump can be carried out without a reflow process
Data Source
AI summary
A semiconductor package includes a set of stud bumps, which can be formed by wire bonding technology and can be bonded or joined to a semiconductor element to form a stacked package assembly. Since the process of bonding the semiconductor element to the stud bumps can be carried out without reflow, an undesirable deformation resulting from high temperatures can be controlled or reduced.