Organometallic Paste for Semiconductor Substrate Stacking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing semiconductor devices with a three-dimensional mounting structure face challenges in downsizing due to the large connecting pitch required for solder balls, which increases thermal deformation and manufacturing costs, and poses reliability issues when using solder balls for electrical connections between stacked substrates.

Innovation Solution

The use of an organometallic column formed by sintering an organometallic paste containing metal particles and metal powder, which provides a conductive connection between wiring substrates at a lower temperature than traditional solder, reducing thermal deformation and eliminating the need for expensive solder balls, allowing for a smaller connecting pitch and thinner substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solder balls are used for electrical connection between stacked substrates, then reliable electrical connection is achieved, but the connecting pitch becomes large and thermal deformation increases

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidconnecting pitch

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The invention changes the material parameter from traditional solder to organometallic paste, which enables bonding at lower temperatures. This parameter change allows for smaller connecting pitch while maintaining connection reliability and reducing thermal deformation of the substrates.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses organometallic paste as a composite material that combines organic and inorganic components. This composite material provides both the electrical conductivity needed for reliable connection and the low-temperature processing characteristics that enable smaller connecting pitch and reduced thermal deformation.

Inventive Principle:

Principle #40Composite materials

2Reliability

If solder balls are used for electrical connection, then electrical connection is achieved, but manufacturing cost increases

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces expensive solder balls with organometallic paste, which is a more cost-effective material. The paste can be applied directly without requiring precision placement equipment, simplifying the manufacturing process and reducing overall manufacturing costs while maintaining connection reliability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention substitutes the mechanical placement process required for solder balls with a simpler paste application process. This eliminates the need for precision positioning equipment and complex placement mechanisms, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If high-temperature reflow process is used for solder ball connection, then strong bonding is achieved, but thermal deformation increases and reliability decreases

Engineering Contradiction:

Improvebonding strengthVSAvoidreflow temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The invention changes the bonding temperature parameter from high-temperature reflow (typically 200-250°C for solder) to low-temperature processing (below 150°C for organometallic paste). This parameter change maintains adequate bonding strength while preventing thermal deformation and improving substrate reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The organometallic paste is designed to bond effectively at lower temperatures, sacrificing the high-temperature processing step. This approach accepts lower processing temperatures as a trade-off to achieve the desired bonding strength without causing thermal damage to the substrates.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 enables the creation of downsized, thinned, and cost-effective semiconductor devices with improved reliability by suppressing thermal deformation and eliminating the need for high-temperature reflow processes, while simplifying the manufacturing process.

Implementation Method 1

an organometallic column formed by sintering an organometallic paste containing metal particles and metal powder

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS8763242B2Semiconductor device and method of manufacturing the same

Publication Date: 2014.07.01 RENESAS ELECTRONICS CORP

AI summary

In a method of manufacturing a semiconductor device, a second wiring substrate is stacked over a first wiring substrate using a conductive paste, where each wiring substrate has mounted thereon an electronic component. The conductive paste is hardened to form a metal column which forms an electrical connection between the first wiring substrate and the second wiring substrate. The wiring substrates are sealed with a resin. The semiconductor device can be downsized, thinned, and made highly reliable, and its manufacturing cost can be reduced. By using conductive paste for the electrical connection between the wiring substrates, a connecting pitch can be smaller than that in a connecting method of using a solder ball including Cu core, and a connection at low temperature can be achieved. Also, by coating the conductive paste by a print-coating or dispense-coating method, manufacturing is simplified and the manufacturing cost is reduced.