Thermally Conductive TSVs for Heat Exposure Reduction

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Solution Overview

Problem

Thermally sensitive semiconductor components, such as transistors in DDR3 RAM, are vulnerable to heat from neighboring circuits, leading to increased current leakage and power consumption as they require higher refresh rates to prevent data loss, necessitating a method to reduce heat exposure effectively.

Innovation Solution

The implementation of thermally conductive through-silicon vias (TSVs) between heat source and heat sensitive circuits on a circuit substrate, along with thermally insulating TSVs, to mitigate heat transfer and prevent heat-induced current leakage, using materials like copper, tungsten, and silver for conductive TSVs and silicon dioxide for insulating TSVs, without extending through the substrate or connecting to active circuitry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If thermally conductive TSVs are placed between heat source circuits and heat sensitive circuits, then heat transfer from heat source to sensitive components is reduced, but device complexity increases due to additional structural elements

Engineering Contradiction:

Improveheat exposure of sensitive componentsVSAvoidcomplexity of TSV structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces thermally conductive TSVs as intermediary elements positioned between heat source circuits and heat sensitive circuits. These TSVs act as thermal mediators that actively conduct heat away from sensitive areas, preventing thermal coupling between neighboring components while maintaining electrical isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the thermal management function by creating dedicated TSV structures that are spatially separated and selectively positioned between specific heat source and heat sensitive circuit pairs. This segmentation allows targeted thermal protection without requiring comprehensive redesign of the entire circuit substrate.

Inventive Principle:

Principle #1Segmentation

2Reliability

If refresh rate is increased to prevent data loss in heated transistors, then data integrity is maintained, but power consumption increases

Engineering Contradiction:

Improvedata integrityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary anti-action by placing thermally conductive TSVs in advance between heat source and heat sensitive circuits to prevent heat accumulation before it can affect transistor operation. This proactive thermal management prevents the need for corrective actions such as increased refresh rates, thereby maintaining data integrity without the associated power penalty.

Inventive Principle:

Principle #9Preliminary anti-action

3Productivity

If circuit substrate is designed with increasing functionality and speed, then performance is improved, but heat generation increases

Engineering Contradiction:

Improvecircuit functionality and speedVSAvoidheat generation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating zones of enhanced thermal conductivity specifically in regions where heat sensitive circuits are located. The thermally conductive TSVs are selectively positioned to provide localized thermal management exactly where needed, allowing high-performance circuit design in other areas without being constrained by global thermal limitations.

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 solution effectively reduces heat transfer from heat source circuits to sensitive components, minimizing power consumption by maintaining lower refresh rates and preserving data integrity, while maintaining structural integrity and reducing heat dissipation through a heat spreader.

Implementation Method 1

thermally conductive through-silicon vias (TSVs) placed between heat source circuits and heat sensitive circuits

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

thermally insulating TSVs placed between the thermally conductive blind TSVs and the heat sensitive circuit

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS8680674B2Methods and structures for reducing heat exposure of thermally sensitive semiconductor devices

Publication Date: 2014.03.25 NXP USA INC

AI summary

A semiconductor device comprises an integrated circuit (IC) die having a top side and a back side. The circuit substrate includes a heat source circuit, a heat sensitive circuit, a package substrate coupled to the top side of the circuit substrate, and a plurality of thermally conductive through-silicon vias (TSVs) formed from the back side of the circuit substrate to near but not through the top side of the circuit substrate.