Resin Mold Die Flow Restriction for Void-Free Chip Encapsulation
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Solution Overview
Problem
Existing resin molding dies face challenges in achieving accurate molding due to voids caused by uneven resin flow, particularly in areas around chips and protruding electrodes, leading to defective products.
Innovation Solution
A mold die with a flow-path restricting mechanism that narrows lateral resin flow paths on both sides of the cavity, ensuring molten resin flows at a consistent speed across the substrate, preventing air entrapment and voids by aligning the flow speed in chip and non-chip areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If molten resin is allowed to flow freely in lateral areas of the substrate, then the resin can fill the cavity quickly, but the resin flows around into the chip area and traps air, causing voids and reducing molding accuracy
Solution Approach 1:
The cavity is divided into multiple independent flow paths: a central flow path for resin to reach the chip area, and lateral flow paths that are restricted by flow path restricting mechanisms. This segmentation prevents resin from freely flowing around into the chip area while maintaining controlled filling speed in each path.
Solution Approach 2:
Different flow path characteristics are provided in different areas: the central flow path allows relatively free flow to ensure chip area filling, while lateral flow paths are locally restricted by flow path restricting mechanisms to prevent air trapping. This local differentiation of flow characteristics resolves the contradiction between filling speed and molding accuracy.
2Manufacturing precision
If gates are configured to allow molten resin to flow simultaneously over an entire long side of a cavity, then resin distribution is improved, but resin in lateral areas goes around into the chip area containing air, likely causing voids
Solution Approach 1:
The gate system is segmented into a main gate for central flow and restricted lateral flow paths. The flow path restricting mechanisms divide the lateral areas into controlled flow channels, preventing resin from forming large pools that would trap air, while still maintaining simultaneous flow distribution across the cavity.
3Measurement precision
If molten resin flows through a narrow space between the substrate and the chip, then precise positioning is achieved, but the resin flows slowly allowing resin in lateral areas to go around and cause voids
Solution Approach 1:
The flow path restricting mechanisms act as hydraulic control elements that regulate resin flow pressure and velocity. By controlling the lateral flow paths, the system maintains sufficient flow pressure to overcome the narrow space resistance between substrate and chip, ensuring both precise positioning and adequate flow speed to prevent void formation.
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 configuration enhances molding accuracy by preventing air inclusion and voids, resulting in higher-quality resin molded products with improved structural integrity.
Implementation Method 1
a flow-path restricting mechanism that is disposed on both lateral sides of the cavity that are perpendicular to the side and that is configured to narrow lateral flow paths, the lateral flow paths being flow paths for the resin material flowing through the cavity
Implementation Method 2
a gate disposed at one side of the cavity and configured to allow the resin material to flow into the cavity
Implementation Method 3
causing the resin material to flow through the gate into the cavity for resin molding of the object to be molded while causing the flow-path restricting mechanism to narrow the lateral flow paths
Data Source
AI summary
A mold die includes: a mold die body that is configured to hold an object to be molded, the object including a substrate and a chip mounted in a central area of the substrate, and that has a cavity which is rectangular in a plan view and which is configured to receive a resin material, the mold die body including: a pot for containing the resin material; a gate disposed at one side of the cavity and configured to allow the resin material to flow into the cavity; and a flow-path restricting mechanism that is disposed on both lateral sides of the cavity that are perpendicular to the one side and that is configured to narrow lateral flow paths, the lateral flow paths being flow paths for the resin material flowing through the cavity in which the chip is not disposed.