Bump Structure for Load Transmission in Substrate Bonding

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Solution Overview

Problem

The existing substrate bonding methods face challenges in ensuring reliable adhesion and electrical conduction due to damage from uniform pressure application, which disperses load and affects connection bumps, leading to impaired reliability.

Innovation Solution

A substrate bonding structure with a counter substrate featuring a bump structure on its top surface, positioned to correspond with the bonding member, having a higher height than the circuit, allowing linear load transmission and protecting the circuit from surface plate pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If uniform pressure is applied from above and below using surface plates, then substrate bonding is achieved, but the circuits on the counter substrate may be damaged and adhesion of connection bumps is deteriorated

Engineering Contradiction:

Improveadhesion of connection bumpsVSAvoiddamage to circuits

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A bump structure is introduced as an intermediary element between the surface plate and the circuit on the counter substrate. This bump structure receives the pressure from the surface plate and transmits it to the connection bumps, preventing direct contact between the surface plate and the circuit, thereby avoiding circuit damage while ensuring proper adhesion of connection bumps

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful direct pressure application to the circuit is extracted by removing the circuit from the pressure transmission path. The bump structure is positioned to correspond with the bonding member, creating a separate pressure transmission path that bypasses the circuit, thus protecting it from damage

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If pressure is applied uniformly from above, then bonding is achieved, but the pressure is dispersed and transmitted to connection bumps by changing direction, preventing sufficient pressure transmission

Engineering Contradiction:

Improveadhesion of connection bumpsVSAvoidpressure transmission to connection bumps

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The pressure transmission is segmented into distinct paths: one path through the bump structure to the connection bumps, and another path through the bonding member to the substrate. This segmentation ensures that pressure is transmitted directly downward to the connection bumps without dispersion or direction change, maintaining sufficient force for reliable adhesion

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11244874B2Substrate bonding structure and substrate bonding method

Publication Date: 2022.02.08 MITSUBISHI ELECTRIC CORP

AI summary

A device (2) is formed on a main surface of a substrate (1). The main surface of the substrate (1) is bonded to the undersurface of the counter substrate (14) via the bonding member (11,12,13) in a hollow state. A circuit (17) and a bump structure (26) are formed on the top surface of the counter substrate (14). The bump structure (26) is positioned in a region corresponding to at least the bonding member (11,12,13), and has a higher height than that of the circuit (17).