Package Lid Dam Structure for Thermal Interface Material Control

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Solution Overview

Problem

Existing semiconductor packages face issues with non-uniform heat dissipation and excessive heat accumulation, particularly in regions of high circuit density and power utilization, leading to potential damage and increased costs due to the use of high-thermal conductivity materials like copper.

Innovation Solution

Incorporating a dam structure made of epoxy material to constrain thermal interface material within a predetermined volume between the semiconductor die and the package lid, ensuring uniform heat dissipation and preventing the thermal interface material from flowing away during reflow operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If high-thermal conductivity materials like copper are used to improve heat dissipation, then heat dissipation performance is improved, but manufacturing cost increases

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using copper only in specific high-power regions where heat dissipation is most critical, rather than using copper throughout the entire package. The lid structure incorporates copper layers selectively positioned to match high-power circuit regions, while other areas use cost-effective alternative materials, thus resolving the contradiction between heat dissipation performance and manufacturing cost.

Inventive Principle:

Principle #3Local quality

2Temperature

If thermal interface material is applied freely to ensure complete coverage, then heat transfer efficiency is improved, but material waste and cost increase

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidthermal interface material waste

Core Design Contradiction:

TemperatureVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by pre-forming the thermal interface material into a shaped structure that matches the target area geometry before application. The TIM is formed with predetermined patterns and dimensions that correspond to the heat-generating regions, allowing precise placement without excessive material application, thus reducing material waste while ensuring complete coverage of critical areas.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If thermal interface material is constrained to prevent flowing during reflow, then material placement precision is improved, but process complexity increases

Engineering Contradiction:

Improvematerial placement precisionVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses an intermediary approach by forming a temporary protective layer or structure over the thermal interface material during the reflow process. This intermediary structure prevents the TIM from flowing or spreading excessively during heating, ensuring precise material placement. After reflow, the intermediary structure is removed or integrates into the final package, thus achieving material placement precision without significantly increasing overall process complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The dam structure enhances uniform heat dissipation, reduces the risk of overheating, and lowers costs by utilizing less expensive materials while maintaining effective heat management.

Implementation Method 1

a thermal interface material layer 124 located between a top surface of the semiconductor die 102 and an internal surface 121 of the package lid 120

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20250316560A1Dam structure on lid to constrain a thermal interface material in a semiconductor device package structure and methods for forming the same

Publication Date: 2025.10.09 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A disclosed semiconductor device includes a package substrate, a first semiconductor die coupled to the package substrate, a package lid attached to the package substrate and covering the semiconductor die, and a thermal interface material located between a top surface of the semiconductor die and an internal surface of the package lid. The semiconductor device may further include a dam formed on the internal surface of the package lid. The dam may constrain the thermal interface material on one or more sides of the first semiconductor die such that the thermal interface material is located within a predetermined volume between the top surface of the first semiconductor die and the internal surface of the package lid during a reflow operation. The package lid may include a metallic material and the dam may include an epoxy material formed as a single continuous structure or may be formed as several disconnected structures.