Bond Pad Corrosion Mitigation via Reversed Curing Sequence

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Solution Overview

Problem

The integration of halogen-containing polymeric protection layers in semiconductor chips leads to corrosion of bond pads due to the formation of 'loose' halogen ions during the ashing process, which react with cleaning solutions, compromising the electrical connection and chip reliability.

Innovation Solution

Reversing the order of the ashing and curing processes ensures that 'loose' halogen ions are re-bonded back into the polymeric material before the scrub process, significantly reducing their concentration and mitigating corrosion to the bond pad.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If halogen-containing polymeric protection layers are used, then protection performance is improved, but bond pad corrosion occurs due to loose halogen ions

Engineering Contradiction:

Improveprotection performanceVSAvoidbond pad corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional process sequence by performing curing before ashing instead of ashing before curing. This reversal prevents loose halogen ions from forming during ashing, thereby eliminating bond pad corrosion while maintaining the protective function of the polymeric layer

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary curing to the polymeric material before the ashing process. This preliminary action stabilizes the halogen atoms within the polymer structure, preventing them from becoming loose ions during subsequent ashing and cleaning operations

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If ashing process is performed before curing, then cleaning effectiveness is improved, but loose halogen ions react with cleaning solutions causing corrosion

Engineering Contradiction:

Improvecleaning effectivenessVSAvoidelectrical connection reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies preliminary curing to stabilize the polymeric structure before ashing. This preliminary anti-action prevents the formation of harmful loose halogen ions that would otherwise react with cleaning solutions during subsequent cleaning steps

Inventive Principle:

Principle #9Preliminary anti-action

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 increases the longevity and reliability of the bond pad by minimizing acid formation and corrosion, thereby enhancing the overall performance and durability of the integrated chip.

Implementation Method 1

curing the polymeric material to form a polymeric protection layer

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

performing a first cleaning process

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11222857B2Method of forming a photoresist over a bond pad to mitigate bond pad corrosion

Publication Date: 2022.01.11 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

In some embodiments, the present disclosure relates to a method including forming an interconnect structure over a substrate. A bond pad may be coupled to the interconnect structure, and a polymeric material may be deposited over the bond pad. In some embodiments, the method further includes performing a patterning process to remove a portion of the polymeric material to form an opening in the polymeric material. The opening directly overlies and exposes the bond pad. Further, the method includes a first cleaning process. The polymeric material is cured to form a polymeric protection layer, and a second cleaning process is performed.