Thick Logic Die PoP Package for Thermal and Interconnect Efficiency

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Solution Overview

Problem

Current semiconductor package technologies face challenges in enhancing thermal dissipation and interconnect efficiency, particularly in Package-on-Package (PoP) structures used in high-end mobile devices, which require improved performance and reliability.

Innovation Solution

A thermally enhanced semiconductor package design featuring a thick logic die mounted on a bottom substrate with copper cored solder balls and sealing resin, creating a gap between substrates to facilitate electrical connection and thermal management, along with a flip-chip configuration and underfill resin for enhanced stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick logic die is used to improve thermal dissipation and interconnect efficiency, then thermal management and electrical connection are enhanced, but the package height and structural complexity increase

Engineering Contradiction:
Improvethermal dissipation efficiencyVSAvoidpackage height
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent utilizes the vertical dimension by stacking multiple substrates (bottom substrate, top substrate, and intermediate substrate) with a thick logic die in between. This vertical stacking approach allows thermal dissipation pathways to extend in the Z-direction, improving heat removal efficiency while maintaining a compact footprint. The gap between substrates is optimized to balance thermal conduction path length with mechanical stability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The thick logic die (125-350 micrometers) is nested between the bottom substrate and top substrate, with copper cored solder balls positioned around it. The sealing resin further nests around the logic die and solder balls, creating a compact integrated structure. This nested arrangement allows the thick die to be accommodated without excessive increase in overall package dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If copper cored solder balls are used to improve electrical connection and thermal conduction, then interconnect efficiency is enhanced, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveelectrical connection efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs copper cored solder balls that combine copper (for thermal conduction) with solder material (for electrical connection and mechanical bonding). This composite structure leverages the high thermal conductivity of copper while maintaining the electrical and mechanical properties of solder, achieving dual functionality in a single component that simplifies the overall interconnect design.

Inventive Principle:
Principle #40Composite materials

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 improves thermal dissipation and interconnect efficiency, enhancing the performance and reliability of semiconductor packages by optimizing the gap height, solder ball aspect ratio, and resin sealing, thereby supporting higher performance in applications like high-end mobile devices.

Implementation Method 1

a plurality of copper cored solder balls disposed between the bottom substrate and the top substrate around the logic die

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a sealing resin filling in the gap between the bottom substrate and the top substrate and sealing the logic die and the plurality of copper cored solder balls in the gap

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

underfill resin is disposed in a space between the logic die and the top surface of the bottom substrate, and wherein the conductive elements are surrounded by the underfill resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4266361A1Semiconductor package having a thick logic die
Publication Date: 2023.10.25 MEDIATEK INC
  • EP4266361A1 patent drawingFigure 1
  • EP4266361A1 patent drawingFigure 2
  • EP4266361A1 patent drawing

AI summary

A semiconductor package (10) includes a bottom substrate (100) and a top substrate (300) space apart from the bottom substrate (100) such that the bottom substrate (100) and the top substrate (300) define a gap therebetween. A logic die (50) is mounted on a top surface (100a) of the bottom substrate (100). The logic die (50) has a thickness of 125-350 micrometers. A plurality of copper cored solder balls (60) is disposed between the bottom substrate (100) and the top substrate (300) around the logic die (50) to electrically connect the bottom substrate (100) with the top substrate (300). A sealing resin (SM) fills into the gap between the bottom substrate (100) and the top substrate (300) and sealing the logic die (50) and the plurality of copper cored solder balls (60) in the gap.