Wafer-Level Underfill Mold with Variable Ports
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional molding methods, such as compression and transfer molding, face challenges in uniformly dispensing underfill materials between stacked package components, especially when dealing with round wafers, leading to non-uniformity and the need for separate steps for underfill dispensing.
Innovation Solution
A wafer-level molding apparatus and method that uses a mold with a top portion and edge ring, featuring injection ports of varying sizes and air vents, allowing simultaneous underfill dispensing and over-molding in a single step, with controlled injection timing and vacuuming to prevent air bubbles and ensure uniform material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If compression molding is used for over-molding, then the molding process can be performed, but separate steps are needed for underfill dispensing
Solution Approach 1:
The patent combines underfill dispensing and over-molding operations into a single integrated process step. The molding compound is formulated to include both the underfill material and the molding compound, allowing simultaneous filling of gaps between stacked dies and over-molding in one operation, thereby eliminating separate underfill dispensing steps
Solution Approach 2:
The invention uses a composite material system where the molding compound incorporates underfill material properties. This composite formulation enables the material to perform dual functions: filling gaps between package components (underfill function) and providing protective molding (over-molding function)
2Productivity
If transfer molding is used to fill underfill and molding compound simultaneously, then process integration is achieved, but non-uniform dispensing occurs on round wafers
Solution Approach 1:
The patent implements non-uniform port sizing where injection ports at different locations have different dimensions. Ports closer to the center of round wafers are larger, while peripheral ports are smaller, compensating for varying flow paths and ensuring uniform material distribution across the entire wafer surface
Solution Approach 2:
The invention modifies the physical parameters of the injection system by varying port sizes and configurations based on location. This parameter adjustment compensates for geometric variations in round wafers, ensuring consistent filling patterns and uniform material distribution regardless of wafer shape
3Ease of manufacture
If conventional molding methods are used, then underfill dispensing can be performed, but non-uniform dispensing occurs between stacked package components
Solution Approach 1:
The patent divides the injection system into multiple separate injection ports distributed across the mold cavity. This segmentation allows independent control and optimization of material flow to different regions, ensuring uniform underfill distribution between stacked package components through coordinated multi-port injection
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
Enables uniform dispensing of molding material across the wafer, reducing void formation and achieving efficient underfill and over-molding in a single process step, suitable for both round and non-round wafers, improving packaging efficiency in integrated circuit assembly.
Implementation Method 1
a vacuum system connected to the air vents, the vacuum system being configured to vacuum the inner space
Implementation Method 2
A plurality of injection ports is connected to the inner space of the mold
Data Source
AI summary
A mold includes a top portion, and an edge ring having a ring-shape. The edge ring is underlying and connected to edges of the top portion. The edge ring includes air vents. The edge ring further encircles the inner space under the top portion of the mold. A plurality of injection ports is connected to the inner space of the mold. The plurality of injection ports is substantially aligned to a straight line crossing a center of the top portion of the mold. The plurality of injection ports has different sizes.