Gas-Permeable Layer for Robust Semiconductor Substrate Bonding

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Solution Overview

Problem

Existing semiconductor device stacking technologies face challenges in forming robust bonds between substrates using materials that evolve gas upon heat curing, leading to peeling and void formation issues.

Innovation Solution

A method involving the application of a gas-permeable layer on the substrates' bonding surfaces, followed by a silicon oxide base material bond layer precursor coating, allows for the formation of a robust bond without gas-related damage by enabling gas escape during heat curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a bonding material with high fluidity is used to form a bond layer between LSI chips, then the bonding process becomes easier, but gas evolution upon curing causes peeling

Engineering Contradiction:

Improvebonding process easeVSAvoidbond layer integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A release film is introduced as an intermediary layer between the bonding material and the LSI chip. This release film allows gas to escape during curing while preventing direct contact between the gas-evolving bonding material and the chip, thereby preventing peeling. The release film serves as a mediator that enables gas permeation while maintaining bond integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The release film is designed with gas-permeable properties, allowing trapped gas to escape during the curing process. This porous structure prevents gas accumulation that would otherwise cause peeling, while still enabling the bonding material to flow and bond effectively.

Inventive Principle:

Principle #31Porous materials

2Reliability

If an insulating sheet in B stage is used to avoid gas evolution peeling, then bond layer integrity is maintained, but the material has limited availability

Engineering Contradiction:

Improvebond layer integrityVSAvoidmaterial availability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The release film serves as a mediator that enables the use of conventional high-fluidity bonding materials without suffering from gas evolution problems. This intermediary approach provides versatility by allowing multiple bonding material options while maintaining reliability through the gas-permeable release film.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If direct joining of bonding surfaces is performed, then joint strength is high, but the bonding surfaces require high flatness and minimal surface roughness

Engineering Contradiction:

Improvejoint strengthVSAvoidsurface flatness requirement

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The release film acts as an intermediary layer that compensates for surface irregularities. By allowing gas to escape through the release film during curing, the bonding process can tolerate higher surface roughness and less stringent flatness requirements while still achieving strong joints.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The introduction of the release film changes the bonding parameters by adding a gas-permeable interface. This allows the bonding process to proceed with relaxed surface preparation requirements while maintaining joint strength through the release film-mediated curing process.

Inventive Principle:

Principle #35Parameter changes

4Temperature

If organic silicon base materials are used for embedment and heat stability, then thermal performance is improved, but large volume of gas evolves upon heat curing causing peeling

Engineering Contradiction:

Improveheat stabilityVSAvoidbond layer integrity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The release film serves as a critical intermediary that enables the use of organic silicon base materials by providing a gas escape path. During heat curing, the release film allows the large volume of gas evolved from these thermally stable materials to escape without causing peeling, thereby maintaining bond layer integrity while achieving superior heat stability.

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

This approach prevents delamination and void formation, enabling reliable bonding of semiconductor devices even with materials that would typically cause issues due to gas evolution during curing.

Implementation Method 1

providing one or both of the substrates on the bonding surface with a gas-permeable layer

Methodology Applied

Scientific EffectGas permeation: Permeation

Implementation Method 2

said bond layer precursor coating is a silicon base material of the type that cures through formation of Si-O-Si bonds by condensation of silanol groups

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentEP2154710B1Substrate joining method and 3-D semiconductor device

Publication Date: 2016.11.16 SHIN ETSU CHEMICAL CO LTD

AI summary

A pair of substrates each having a bonding surface are joined together by interposing a bond layer precursor coating between the bonding surfaces of the substrates and heating the precursor coating to form a bond layer. Prior to the joining step, the substrate on the bonding surface is provided with a gas-permeable layer. Even when a material which will evolve a noticeable volume of gas upon heat curing is used as the precursor coating, substrates can be joined via a robust bond without the peeling problem by gas evolution.