Metal TIM Lid Bonding for Reliable Semiconductor Heat Dissipation

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Solution Overview

Problem

Existing semiconductor device packaging structures face challenges in heat dissipation and reliability due to stress on metal thermal interface materials (TIM) during thermal cycling, leading to potential delamination issues.

Innovation Solution

A novel metal lid attachment approach using a thermal compression bonding process with a metal TIM, where the thickness and lateral sidewall shape of the TIM are controlled to reduce stress and improve reliability, allowing direct bonding of the metal lid to the semiconductor device without an adhesive layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metal thermal interface material (TIM) is used between the metal lid and semiconductor device, then heat dissipation is improved, but stress during thermal cycling causes TIM delamination

Engineering Contradiction:

Improveheat dissipationVSAvoidTIM delamination resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies curvature to the lateral sidewall of the metal TIM, forming a concave arc shape instead of a straight vertical wall. This curved geometry allows the TIM to better accommodate thermal expansion and contraction stresses during thermal cycling, reducing delamination while maintaining effective heat dissipation from the semiconductor device to the metal lid.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent modifies the geometric parameters of the metal TIM, specifically controlling its thickness and lateral sidewall shape. By optimizing these parameters—creating a concave arc profile with controlled thickness—the TIM achieves improved stress distribution and bonding interface stability, preventing delamination while preserving thermal conduction performance.

Inventive Principle:

Principle #35Parameter changes

2Strength

If an adhesive layer is added to attach the metal lid to the package substrate, then bonding strength is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improvebonding strengthVSAvoidpackage structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent merges the functions of the metal TIM and adhesive layer into a single component. The metal TIM is designed to perform both thermal conduction and bonding functions simultaneously, eliminating the need for a separate adhesive layer. This integration reduces package structure complexity and manufacturing steps while maintaining adequate bonding strength between the metal lid and semiconductor device.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The metal TIM is designed as a multi-functional component that simultaneously provides thermal conduction and mechanical bonding. By making the TIM universal in its functions, the patent eliminates the need for additional specialized adhesive layers, simplifying the overall package structure and reducing manufacturing complexity while achieving both heat dissipation and bonding requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the thickness and lateral sidewall shape of metal TIM are controlled, then stress is reduced and reliability is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvestress reductionVSAvoidTIM thickness and shape control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies controlled parameter ranges for the metal TIM thickness and lateral sidewall shape to achieve the concave arc profile. By defining acceptable parameter ranges rather than requiring exact dimensions, the patent balances manufacturing feasibility with stress reduction goals, maintaining reliability improvements while accommodating normal manufacturing tolerances.

Inventive Principle:

Principle #35Parameter changes

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 the semiconductor device package by reducing the risk of TIM delamination and eliminating the need for an adhesive layer, thereby improving heat dissipation and package reliability.

Implementation Method 1

a metal TIM provided between the metal lid and the semiconductor device

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

heating the metal TIM to melt the metal TIM

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11742218B2Semiconductor device package having metal thermal interface material and method for forming the same

Publication Date: 2023.08.29 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for forming a semiconductor device package is provided. The method includes bonding a semiconductor device to a package substrate; placing a metal lid over the semiconductor device and the package substrate with a metal thermal interface material (TIM) provided between the metal lid and the semiconductor device; heating the metal TIM to melt the metal TIM; pressing the metal lid downward so that the molten metal TIM flows toward the boundary of the semiconductor device, and the outermost point of the lateral sidewall of the molten metal TIM extends beyond the boundary of the semiconductor device; lifting the metal lid upward so that the molten metal TIM flows back, and the outermost point of the lateral sidewall is within the boundary of the semiconductor device; and bonding the metal lid to the semiconductor device through the metal TIM by curing the molten metal TIM.