Semiconductor Package Tapered Mold Cavity Resin Flow
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Solution Overview
Problem
The challenge in manufacturing semiconductor packages, particularly side-view type light emitting devices, is the occurrence of weld lines and short shots due to the rapid cooling and solidification of molten resin, which limits the achievable wall thickness and affects the luminance of the device, as thinner packages are difficult to mold without resin flow issues and burrs.
Innovation Solution
A semiconductor package design with a protrusion on the back surface and a recessed step to prevent inclination during mounting, combined with a metal mold having a larger gate diameter and tapered projection to facilitate resin filling and reduce pressure, allowing for a thinner package structure without weld lines and short shots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package wall is made thinner to reduce device size, then the device size is reduced, but weld lines and short shots occur more frequently due to rapid resin cooling
Solution Approach 1:
The patent changes the geometric parameters of the mold cavity, specifically creating a tapered shape where the width increases from the gate toward the front surface. This parameter change allows the resin to flow more easily through the thin wall portion without rapid cooling, preventing weld lines and short shots while maintaining thin package dimensions.
Solution Approach 2:
The patent introduces a dimensional variation in the mold cavity width along the resin flow path. By making the cavity width change in the flow direction (larger at front, smaller at gate), it creates a three-dimensional flow path that compensates for the thin wall thickness, allowing complete filling without defects.
2Manufacturing precision
If the gate diameter is increased to improve resin filling, then resin filling is improved, but the package structure becomes more complex
Solution Approach 1:
The patent changes the gate diameter parameter to be larger than the minimum required, specifically making it 0.05mm or more. This parameter change, combined with the tapered cavity shape, ensures complete resin filling without requiring complex multi-gate structures or additional molding features.
3Manufacturing precision
If injection pressure is increased to prevent short shots, then resin filling is improved, but resin burrs are generated
Solution Approach 1:
The patent changes the geometric parameters of the mold cavity (tapered shape with increasing width) to allow complete resin filling at lower injection pressures. This parameter change ensures that the resin fills the thin wall portion completely without requiring high pressure that would cause burr formation at the gate or mold seams.
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 design enables the production of thinner semiconductor packages with improved stability and reliability, minimizing the risk of weld lines and short shots, while maintaining or enhancing the luminance of the light emitting devices by allowing a larger light emitting element size and improved resin filling without increased pressure.
Implementation Method 1
a molten resin is injected into a mold cavity through a sprue and runner and from a gate of a metal mold, and is retained for a predetermined period of time to cool and solidify to obtain a molded body
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3~4
AI summary
A semiconductor package mounted with a semiconductor component comprising a package upper surface and a package lower surface, and a package front surface and a package back surface, facing each other respectively, wherein the package front surface and the package back surface are adjacent to the package upper surface and the package lower surface respectively, the package upper surface and the package lower surface are disposed so that the thickness of the package decreases from the package front side toward the package back surface side, and a protrusion is formed on at least either the package upper surface or the package lower surface so as to be continuous to the package back surface, wherein a recess step is formed by defining a recess approximately in the center of the package back surface, and a protrusion is formed protruding from the bottom surface of the recess step and the top of the protrusion is fit within the recess step.