Interconnect Substrate Columnar Electrodes Reflow Height Control

Solution Overview

Problem

Semiconductor packages with connection terminals of varying diameters often experience short-circuiting and connection failures due to height differences between large-diameter and small-diameter terminals, leading to reduced reliability.

Innovation Solution

The interconnect substrate features first and second connection terminals with columnar electrodes and bumps, where the second terminal has a concave surface and a larger diameter, and both bumps have a lower melting point than their respective electrodes, ensuring equal peak heights after a reflow process, thereby preventing short-circuiting and connection failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If connection terminals with different diameters are used to accommodate various semiconductor chips, then adaptability is improved, but height differences between large-diameter and small-diameter terminals cause short-circuiting and connection failures

Engineering Contradiction:

ImproveadaptabilityVSAvoidreliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by giving different surface shapes to columnar electrodes based on their diameter. Large-diameter electrodes have concave surfaces while small-diameter electrodes have flat surfaces, allowing each local region to be optimized for its specific function. This resolves the contradiction by enabling adaptability through varying electrode configurations while maintaining reliability through localized height control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters (surface shape and diameter) of columnar electrodes to achieve different heights after bump formation. By controlling whether the surface is concave or flat and adjusting the diameter, the final height of connection terminals can be equalized despite different electrode sizes, thus maintaining both adaptability and reliability.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If large-diameter terminals are used, then connection capacity is improved, but height differences cause short-circuiting between bumps

Engineering Contradiction:

Improveconnection capacityVSAvoidshort-circuiting

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by giving different surface shapes to columnar electrodes based on their diameter. Large-diameter electrodes have concave surfaces while small-diameter electrodes have flat surfaces, allowing each local region to be optimized for its specific function. This resolves the contradiction by enabling adaptability through varying electrode configurations while maintaining reliability through localized height control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies preliminary anti-action by pre-shaping the columnar electrode surfaces (concave for large-diameter, flat for small-diameter) before bump formation. This preliminary configuration prevents the harmful effect of height differences and potential short-circuiting from occurring in the first place, rather than attempting to correct it after the fact.

Inventive Principle:

Principle #9Preliminary anti-action

3Manufacturing precision

If small-diameter terminals are used, then connection precision is improved, but connection failures occur due to insufficient contact

Engineering Contradiction:

Improveconnection precisionVSAvoidconnection reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by giving different surface shapes to columnar electrodes based on their diameter. Large-diameter electrodes have concave surfaces while small-diameter electrodes have flat surfaces, allowing each local region to be optimized for its specific function. This resolves the contradiction by enabling adaptability through varying electrode configurations while maintaining reliability through localized height control.

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 design enhances the reliability of connections by aligning the heights of large-diameter and small-diameter terminals, preventing spilling and ensuring proper contact during semiconductor chip mounting, thus improving the overall reliability of the semiconductor package.

Implementation Method 1

both bumps have a lower melting point than their respective electrodes, ensuring equal peak heights after a reflow process

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11121107B2Interconnect substrate having columnar electrodes

Publication Date: 2021.09.14 SHINKO ELECTRIC IND CO LTD

AI summary

An interconnect substrate includes a substrate, and a first connection terminal and a second connection terminal that are disposed on a surface of the substrate, wherein the first connection terminal includes a first columnar electrode and a first bump disposed on the first columnar electrode, the first columnar electrode having a flat or convex surface and having a first diameter, wherein the second connection terminal includes a second columnar electrode and a second bump disposed on the second columnar electrode, the second columnar electrode having a concave surface and having a second diameter larger than the first diameter, and wherein a melting point of the first bump and the second bump is lower than a melting point of the first columnar electrode and the second columnar electrode.