Al Bond Pad Moisture Removal via Precursor Reaction

Solution Overview

Problem

Moisture contamination in polymer materials used in bond pad fabrication degrades contact resistance between aluminum bond pads and under bump metallization or redistribution layers, as existing cooling methods are time-consuming and ineffective.

Innovation Solution

A method involving the use of a moisture-sensitive precursor to react with moisture in polymer materials, forming a metal oxide that locks in moisture and prevents contamination, followed by plasma cleaning and deposition of metal layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cooling methods are used to reduce moisture in polymer materials, then moisture content is reduced, but processing time increases and effectiveness is insufficient

Engineering Contradiction:

Improvemoisture content in polymerVSAvoidprocessing time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent replaces the mechanical cooling system with a chemical reaction system. A moisture-sensitive precursor (such as aluminum-containing precursor) is deposited onto the polymer surface, where it chemically reacts with moisture to form metal hydroxides or oxides. This chemical approach directly removes moisture without requiring time-consuming cooling processes, thereby reducing processing time while effectively lowering moisture content.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from physical parameter control (temperature reduction via cooling) to chemical parameter utilization (reactivity of moisture-sensitive precursor). By selecting precursors with high moisture sensitivity and appropriate reaction kinetics, the process achieves rapid moisture removal at conventional processing temperatures, avoiding the time penalty associated with cooling while maintaining effectiveness.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If cooling methods are used to reduce moisture in polymer materials, then moisture content is reduced, but the effectiveness is insufficient

Engineering Contradiction:

Improvemoisture content in polymerVSAvoidmoisture removal effectiveness

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent replaces the mechanical cooling system with a chemical reaction system. A moisture-sensitive precursor (such as aluminum-containing precursor) is deposited onto the polymer surface, where it chemically reacts with moisture to form metal hydroxides or oxides. This chemical approach directly removes moisture without requiring time-consuming cooling processes, thereby reducing processing time while effectively lowering moisture content.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The moisture-sensitive precursor acts as a strong chemical agent that rapidly reacts with moisture. The chemical reaction proceeds quickly and completely, converting moisture into bound water in the form of metal hydroxides or oxides. This accelerated chemical process achieves superior moisture removal effectiveness compared to gradual physical cooling, ensuring reliable contamination prevention.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

3Reliability

If moisture is present in polymer materials, then contact resistance between bond pads and metal layers increases, but removing moisture requires time-consuming cooling

Engineering Contradiction:

Improveelectrical conductivityVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs moisture removal as a preliminary step before metal layer deposition. A moisture-sensitive precursor is deposited onto the polymer surface in advance, where it reacts with and locks up moisture. This preliminary chemical treatment ensures that when the bond pad area is exposed and metal layers are subsequently deposited, the polymer material is already free of free moisture that would cause contamination, thereby ensuring low contact resistance without requiring time-consuming cooling steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical cooling system with a chemical reaction system. A moisture-sensitive precursor (such as aluminum-containing precursor) is deposited onto the polymer surface, where it chemically reacts with moisture to form metal hydroxides or oxides. This chemical approach directly removes moisture without requiring time-consuming cooling processes, thereby reducing processing time while effectively lowering moisture content.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Effectively removes moisture from polymer materials adjacent to bond pads, preventing contamination and ensuring reliable electrical conductivity, thereby improving the bonding process efficiency.

Implementation Method 1

forming a compound on the substrate from a reaction between the moisture in the one or more films and the moisture sensitive precursor

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

cleaning the exposed device interconnect layer with a plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS9082828B2Al bond pad clean method

Publication Date: 2015.07.14 APPLIED MATERIALS INC

AI summary

Embodiments of the present disclosure provide a method for controlling moisture from substrate being processed. Particularly, embodiments of the present disclosure provide methods for removing moisture from polymer materials adjacent bond pad areas. One embodiment of the present includes providing a moisture sensitive precursor and forming a compound from a reaction between the moisture to be controlled and the moisture sensitive precursor.