Semiconductor Molding Gate Asymmetry to Reduce Resin Voids

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Solution Overview

Problem

In the mold array process (MAP) for manufacturing semiconductor devices, air stagnation in grooves or stepped portions of the base material during resin injection leads to void formation in the sealing resin layer, compromising the reliability and yield rate of the semiconductor devices.

Innovation Solution

The method involves arranging the gates of the molding die at positions different from the extended lines of the dicing regions on the base material, ensuring that the resin injection occurs from the first side toward the second side, with the vertex of the resin advancing fastest into the second region, thereby reducing air entrainment and void formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If resin injection is performed through gates positioned on the extended line of dicing regions, then manufacturing efficiency is maintained, but air stagnation occurs in grooves causing void formation and reduced reliability

Engineering Contradiction:

Improvereliability of semiconductor deviceVSAvoidgate arrangement simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry by positioning gates at specific locations that are not symmetrically aligned with the dicing region extended lines. The gates are arranged asymmetrically relative to the grooves and dicing regions, which prevents air stagnation while maintaining effective resin injection. This asymmetric positioning resolves the contradiction by avoiding void formation without significantly complicating the manufacturing process.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements preliminary action by pre-positioning the gates at optimized locations before resin injection begins. The gate positions are predetermined based on the dicing region geometry and groove locations, ensuring that resin flow paths are optimized from the start to prevent air entrapment. This preliminary planning allows reliable resin injection without requiring complex real-time adjustments during manufacturing.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If resin is injected quickly to improve productivity, then manufacturing speed increases, but air entrainment in grooves increases causing more voids

Engineering Contradiction:

Improveresin injection speedVSAvoidquality of sealing resin layer

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by optimizing resin injection characteristics at different locations. The gate positions are specifically selected to create favorable local flow conditions in regions with grooves, allowing faster injection speeds without causing air entrapment. The resin flow is locally optimized by positioning gates such that the flow direction and pressure distribution prevent air stagnation in groove areas while maintaining high productivity.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If gates are positioned to avoid dicing region extended lines, then void formation is reduced, but device complexity increases due to precise gate positioning requirements

Engineering Contradiction:

Improvepositioning accuracy of gatesVSAvoidmolding die configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the molding die into multiple sections, each with its own gate positioned to avoid the extended lines of dicing regions. This segmentation allows each gate to be independently optimized for its local geometry, reducing void formation while keeping the overall device complexity manageable. The molding die is effectively divided into multiple zones with tailored gate configurations.

Inventive Principle:

Principle #1Segmentation

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 approach enhances the reliability of semiconductor devices by minimizing voids and improving the yield rate by ensuring a smoother resin flow and reducing air entrainment during the resin injection process.

Implementation Method 1

injecting resin into the cavity from the gates and forming a sealing resin layer over the main surface of the base material

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS10186432B2Method for manufacturing semiconductor device

Publication Date: 2019.01.22 RENESAS ELECTRONICS CORP

AI summary

The reliability of a semiconductor device is improved.During resin injection in a molding step, in a plan view, a plurality of gates of a molding die are arranged at positions different from those over extended lines of a plurality of dicing regions and a resin is injected from the gates. In this way, it becomes possible to reduce entrainment of air in the dicing regions and to lower an occurrence rate of voids. As a consequence, it becomes possible to suppress an occurrence of poor appearance such as formation of voids in a sealing body and to suppress formation of a starting point of a crack which may occur during a reflow process. Thus, the reliability of the semiconductor device can be improved.