Staggered Semiconductor Die Underfill Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor packages with stacked dies, the protruding portions of dies lack support during wire bonding, leading to bending, poor registration, unreliable bonds, and potential damage due to the absence of underfill material under the cantilevered sections.
Innovation Solution
The introduction of underfill material under the protruding portions of stacked dies provides mechanical support, reducing deflection and enhancing wire bonding reliability by curing the underfill to form a stable support structure beneath the dies during the bonding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dies are stacked in a staggered manner to allow exposure of bond pads, then wire bonding accessibility is improved, but the protruding portions of dies lack support and bend during wire bonding
Solution Approach 1:
Underfill material is applied to the substrate before the die is mounted, creating a support structure in advance. This preliminary action ensures that when the die is stacked in a staggered manner, the protruding portions have immediate support, preventing bending during wire bonding while maintaining bond pad accessibility.
Solution Approach 2:
Underfill material acts as an intermediary substance between the substrate and the die. It fills the space under the protruding portions of the die, providing mechanical support and stability. This intermediary structure enables the die to maintain its position and resist bending forces during wire bonding operations.
2Manufacturing precision
If underfill material is provided under protruding portions of stacked dies, then die deflection during wire bonding is reduced, but manufacturing process complexity increases
Solution Approach 1:
The underfill material is applied to the substrate before die mounting, creating a pre-formed support structure. This preliminary preparation simplifies the overall manufacturing process by eliminating the need for complex support structures or post-mounting adjustments, while ensuring high wire bonding registration accuracy.
Solution Approach 2:
The invention changes the physical state and distribution of the underfill material by applying it in a controlled manner before die mounting. This parameter change in the manufacturing process allows for precise control of underfill placement, achieving high manufacturing precision without significantly increasing process 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
The use of underfill material significantly reduces die deflection and misalignment during wire bonding, resulting in more reliable and robust wire bonds, while minimizing the risk of die damage, and allows for thinner dies without increased cracking risks.
Implementation Method 1
curing the underfill to form a stable support structure beneath the dies during the bonding process
Data Source
AI summary
Semiconductor packages with electromagnetic interference supported stacked die and a method of manufacture therefor is disclosed. The semiconductor packages may house a stack of dies in a system in a package (SiP) implementation, where one or more of the dies may be wire bonded to a semiconductor package substrate. The dies may be stacked in a partially overlapping, and staggered manner, such that portions of some dies may protrude out over an edge of a die that is below it. This dies stacking may define a cavity, and in some cases, wire bonds may be made to the protruding portions of the die. Underfill material may be provided in the cavity and cured to form an underfill support. Wire bonding of the bond pads overlying the cavity formed by the staggered stacking of the dies may be performed after the formation of the underfill support.