Cu Substrate Bonding with Plasma Oxidation Suppression
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Solution Overview
Problem
Existing methods for bonding substrates with conductive Cu layers face issues such as oxidation, photocorrosion, and reduced bonding reliability due to reactions with water and oxygen, leading to defects and increased electrical resistance.
Innovation Solution
A method involving plasma activation, formation of an oxidation suppression layer using Si or Al to prevent Cu oxidation, followed by hydroxyl group bonding and heat treatment to enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is exposed to plasma for surface activation, then bonding reliability is improved, but oxidation of Cu occurs leading to defects and increased electrical resistance
Solution Approach 1:
The patent applies preliminary action by forming the oxidation suppression layer immediately after plasma activation while the surface is still in a reactive state. The sequence of plasma treatment followed by immediate oxidation suppression layer formation prevents oxidation before it can occur, addressing the contradiction by performing the protective action at the optimal moment when surface reactivity is highest but oxidation risk is尚未 manifest
Solution Approach 2:
The oxidation suppression layer acts as an intermediary substance between the activated Cu surface and the oxidizing environment. This intermediate layer prevents direct contact between oxygen/water and the Cu surface, allowing the benefits of plasma activation to be retained while blocking the harmful oxidation effect
2Strength
If water is supplied to form hydroxyl groups for bonding, then bonding strength is enhanced, but photocorrosion and oxidation reactions increase
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming the oxidation suppression layer before water supply and hydroxyl group formation. This preliminary protective measure counteracts the potential harmful effects of subsequent water exposure and photocorrosion, allowing hydroxyl groups to form for bonding while the suppression layer prevents oxidation and corrosion reactions
3Device complexity
If conventional bonding methods are used without oxidation suppression, then process simplicity is maintained, but bonding reliability decreases due to oxidation and defects
Solution Approach 1:
The oxidation suppression step is integrated into the existing bonding process sequence as a preliminary action between plasma activation and hydroxyl group formation. This maintains overall process simplicity while adding the necessary protective measure, as the suppression layer formation uses standard plasma processing equipment and procedures already present in semiconductor manufacturing
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
The method effectively suppresses oxidation and photocorrosion, improving bonding reliability and reducing defects, thereby enhancing the electrical properties of the conductive layers.
Implementation Method 1
exposing the substrate to plasma of a first process gas
Implementation Method 2
forming an oxidation suppression layer that suppresses oxidation of Cu on a surface of the conductive layer by exposing the substrate after activating the surface of the substrate to plasma of a second process gas
Implementation Method 3
forming a hydroxyl group on the surface of the substrate by supplying water to the surface of the substrate after forming the oxidation suppression layer
Implementation Method 4
heat-treating the bonded substrates
Data Source
AI summary
A substrate processing method includes activating a surface of a substrate having a conductive layer containing Cu and an insulating layer by exposing the substrate to plasma of a first process gas, forming an oxidation suppression layer that suppresses oxidation of Cu on a surface of the conductive layer by exposing the substrate after activating the surface of the substrate to plasma of a second process gas, forming a hydroxyl group on the surface of the substrate by supplying water to the surface of the substrate after forming the oxidation suppression layer, bonding the substrate after forming the hydroxyl group to another substrate after forming the hydroxyl group, and heat-treating the bonded substrates.