Thermal Interface Material Placement in 3D Semiconductor Packaging

Solution Overview

Problem

Three-dimensional integrated circuits face challenges with heat dissipation, which can lead to reduced reliability and operating lifetime, especially in high-power components like CPUs, due to excessive temperature exposure.

Innovation Solution

The use of a thermal interface material applied to semiconductor substrates before underfill material, combined with a thermally conductive ring and lid structure, enhances heat transfer and prevents underfill material interference, thereby improving thermal dissipation and mechanical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal interface material is applied after underfill material, then underfill material can provide mechanical support, but thermal interface material cannot be properly applied to the substrate surface

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidthermal interface quality

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The thermal interface material is applied to the substrate surface before the underfill material is dispensed. This preliminary action ensures that the thermal interface material has direct contact with the substrate, guaranteeing effective thermal coupling while the underfill material is subsequently applied to provide mechanical support and sealing.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If underfill material is applied extensively to provide mechanical support, then structural stability improves, but thermal interference increases and blocks heat transfer paths

Engineering Contradiction:

Improvemechanical stabilityVSAvoidthermal dissipation

Core Design Contradiction:

Stability of the object's compositionVSTemperature

Solution Approach 1:

The underfill material is applied in a controlled manner with specific attention to avoiding the thermal interface material application area. This local quality approach ensures that the underfill material provides mechanical support and stability where needed while leaving the thermal interface material exposed and functional for effective heat transfer.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thermal interface material serves as an intermediary layer between the substrate and the thermal management system. By applying it before the underfill material, it acts as a protective barrier that ensures thermal contact is established first, while the subsequent underfill material provides mechanical support without interfering with the thermal interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If thermal interface material is applied before underfill material, then heat transfer efficiency improves, but underfill material may interfere with thermal interface material application

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidmaterial application process

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The thermal interface material is applied to the substrate surface before the underfill material is dispensed. This preliminary action ensures that the thermal interface material has direct contact with the substrate, guaranteeing effective thermal coupling while the underfill material is subsequently applied to provide mechanical support and sealing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The underfill material is applied in a controlled manner with specific attention to avoiding the thermal interface material application area. This local quality approach ensures that the underfill material provides mechanical support and stability where needed while leaving the thermal interface material exposed and functional for effective heat transfer.

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 configuration effectively increases heat transfer from the substrates to a lid, reducing thermal interference from underfill materials and enhancing the reliability and efficiency of heat dissipation in semiconductor packaging.

Implementation Method 1

A first thermal interface material may be placed on the second substrate, wherein the placing the first thermal interface material places the first thermal interface material on a first side of the second substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a thermally conductive ring and lid structure, enhances heat transfer and prevents underfill material interference, thereby improving thermal dissipation

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10867835B2Semiconductor packaging structure and process

Publication Date: 2020.12.15 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method and structure for packaging a semiconductor device are provided. In an embodiment a first substrate is bonded to a second substrate, which is bonded to a third substrate. A thermal interface material is placed on the second substrate prior to application of an underfill material. A ring can be placed on the thermal interface material, and an underfill material is dispensed between the second substrate and the third substrate. By placing the thermal interface material and ring prior to the underfill material, the underfill material cannot interfere with the interface between the thermal interface material and the second substrate, and the thermal interface material and ring can act as a physical barrier to the underfill material, thereby preventing overflow.