Staggered Offset Mesh Blocks Minimize Mold Bleeding

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Solution Overview

Problem

Mold bleeding during semiconductor packaging leads to reduced quality and productivity due to the aligned mesh block design on the substrate surface, which causes drainage flow and worsens bleeding, especially at the edges, necessitating additional processes for removal.

Innovation Solution

The formation of staggered offset mesh block areas on the substrate surface acts as dam structures to block the flow of mold material, with strategically designed airvents and gaps to minimize mold bleeding, using heat conductive materials to reduce warpage and enhance packaging efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If aligned mesh block design is used on the substrate surface, then warpage performance is improved, but mold bleeding is worsened due to drainage flow

Engineering Contradiction:

Improvewarpage performanceVSAvoidmold bleeding

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the symmetric aligned mesh block design to an asymmetric staggered offset mesh block design. The mesh blocks are arranged in a staggered pattern where blocks in adjacent rows are offset from each other, creating an asymmetric structure that blocks drainage flow while maintaining warpage control. This asymmetric arrangement prevents the continuous flow path that causes mold bleeding at the edges.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent segments the continuous mesh block structure into discrete, separated blocks arranged in a staggered pattern. By dividing the mesh structure into individual blocks with gaps between them, the drainage flow is interrupted and blocked, preventing mold material from flowing along the edges while still providing structural support for warpage control.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If aligned mesh block design with wide gaps is used, then manufacturing ease is improved, but mold bleeding is worsened due to drainage flow

Engineering Contradiction:

Improvemesh block design fabricationVSAvoidmold bleeding

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The staggered offset arrangement creates an asymmetric pattern that is equally easy to manufacture as aligned blocks but effectively blocks drainage flow. The offset pattern prevents continuous flow paths while maintaining simple geometric shapes that are easy to fabricate, resolving the contradiction between manufacturing ease and mold bleeding prevention.

Inventive Principle:

Principle #4Asymmetry

3Productivity

If airvents are formed on the substrate surface, then air expulsion is improved, but mold bleeding is worsened due to material flow through vents

Engineering Contradiction:

Improveair expulsion efficiencyVSAvoidmold bleeding

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different local qualities to different areas: airvents are provided in the inner area to ensure efficient air expulsion, while the outer area uses staggered offset mesh blocks to block mold material flow. This localized differentiation allows air vents to function effectively without causing edge bleeding, as the mesh blocks prevent material from following the vent paths to the edges.

Inventive Principle:

Principle #3Local quality

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 significantly reduces mold bleeding, improving the quality and yield of semiconductor packages by containing the mold material flow and enhancing the cosmetic appeal and productivity in semiconductor manufacturing.

Implementation Method 1

blocking a flow of a mold material from a mold cavity of the semiconductor package to the outer area of the substrate surface using the staggered offset mesh block areas

Methodology Applied

Scientific EffectPhysical barrier blocking:

Implementation Method 2

using heat conductive materials to reduce warpage and enhance packaging efficiency

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS7759171B2Method and structure of minimizing mold bleeding on a substrate surface of a semiconductor package

Publication Date: 2010.07.20 INFINEON TECHNOLOGIES LLC

AI summary

A method and structure of minimizing mold bleeding on a substrate surface of a semiconductor package is disclosed. In one embodiment, a method includes forming a dam structure on an outer area of a substrate surface of a semiconductor package and blocking a flow of a mold material from a mold cavity of the semiconductor package to the outer area of the substrate surface using the dam structure. In another embodiment, a substrate surface of a semiconductor package includes product forming areas to provide mounting spaces of semiconductor chips and staggered offset mesh block areas surrounding the product forming areas to act as dam structures to minimize mold bleeding from a mold cavity of the semiconductor package to outer areas of the substrate surface.