Vacuum Compression Molding Chamber for Void-Free Underfill
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Solution Overview
Problem
The formation of voids in the molded underfill during the compression molding process of semiconductor packages leads to defects such as bump extrusion in subsequent processes, necessitating a solution to maintain a vacuum environment within the molding dies.
Innovation Solution
A semiconductor package molding apparatus and system that includes a chamber structure with vacuum units to maintain a vacuum within the cavity, preloader units to preheat and degas the molding material, and transfer arms to precisely position the material and target within the chamber, ensuring a void-free encapsulation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compression molding is performed without vacuum environment, then the molding process is simpler and faster, but voids are formed in the molded underfill causing defects
Solution Approach 1:
The patent applies vacuum environment (inert atmosphere principle) by equipping the molding apparatus with vacuum units that maintain negative pressure in the molding cavity during the molding process. This prevents air entrapment and void formation in the underfill, ensuring high reliability of the molded product while managing the complexity through integrated vacuum systems.
2Reliability
If vacuum units are added to maintain vacuum in molding dies, then void formation is prevented, but the apparatus complexity increases
Solution Approach 1:
The patent merges the vacuum maintenance function directly into the molding chamber structure by integrating vacuum units with the chamber. This combination approach achieves void-free encapsulation while minimizing apparatus complexity by consolidating functions rather than adding separate standalone vacuum systems.
3Manufacturing precision
If preloader units are used to preheat and degas molding material, then molding quality improves, but the apparatus complexity and process time increase
Solution Approach 1:
The patent applies preliminary action by using preloader units to preheat and degas the molding material before the actual compression molding process. This preparation step ensures high manufacturing precision of the molded product by eliminating air bubbles and achieving proper material temperature, while the integrated design minimizes the time penalty through efficient sequential processing.
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 prevents void formation in the molded underfill, thereby reducing defects and improving the quality of semiconductor packages by ensuring a consistent and controlled encapsulation process.
Implementation Method 1
a first vacuum configured to discharge air from the first cavity
Implementation Method 2
a second mold including a first heater
Data Source
AI summary
A semiconductor package molding apparatus includes a chamber including: a first chamber structure including a first mold on which a molding target is configured to be seated; a second chamber structure configured to be clamped to the first chamber structure such as to isolate an interior of the chamber from an exterior of the chamber, the second chamber structure including a second mold, wherein the first mold and the second mold are configured to form a first cavity therebetween; and a first vacuum configured to discharge air from the first cavity. The semiconductor package molding apparatus further includes preloader on a side face of the chamber, the preloader including: a second cavity; a third mold configured to have a molding material seated thereon; a second vacuum configured to discharge air from the second cavity, and a first transfer arm configured to seat the molding material on the second mold.