Semiconductor Substrate Rinse Liquid for High-k Gate Insulator Film Loss
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Solution Overview
Problem
The existing methods for rinsing semiconductor substrates using deionized water result in significant film loss of rare earth and alkaline earth oxide cap layers, which is detrimental to the thickness and uniformity of the gate insulating films, particularly in High-k gate insulating film structures, leading to variations in transistor characteristics.
Innovation Solution
A substrate treatment method involving a rinse step with an alkaline chemical or organic solvent, such as ammonia water or isopropyl alcohol, is employed to minimize film loss, ensuring the film thickness remains within precise limits, thereby maintaining the integrity of the cap layer and improving device characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If deionized water is used for rinsing the substrate, then the rinsing process is simple and cost-effective, but significant film loss occurs in the cap layer
Solution Approach 1:
The patent changes the chemical composition parameter of the rinse liquid from deionized water to an organic solvent (such as isopropyl alcohol, acetone, or cyclohexane). This parameter change eliminates the etching effect on the cap layer while maintaining effective rinsing capability, thus resolving the contradiction between process simplicity and film loss prevention.
2Ease of operation
If deionized water is used for rinsing, then the process is easy to implement, but film thickness uniformity deteriorates
Solution Approach 1:
The patent modifies the chemical parameter of the rinse liquid from water-based to organic solvent-based. This change eliminates the chemical interaction that causes non-uniform etching, thereby maintaining film thickness uniformity while keeping the rinsing process simple and easy to implement.
3Device complexity
If deionized water rinsing is used, then equipment requirements are minimal, but cap layer integrity is compromised
Solution Approach 1:
The patent changes the chemical parameter of the rinse liquid to an organic solvent, which does not chemically react with or etch the cap layer. This maintains cap layer integrity and reliability while requiring no changes to the rinsing equipment, thus keeping device complexity minimal.
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 use of alkaline chemicals or organic solvents significantly reduces film loss during the rinse step, allowing for precise control of film thickness and uniformity, thereby enhancing the electrical characteristics of semiconductor devices by maintaining the cap layer thickness and preventing surface deformation.
Implementation Method 1
a rinse step of supplying the oxide film on the semiconductor substrate with a rinse liquid made of an alkaline chemical (pH 7 to pH 14) or an organic solvent
Data Source
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AI summary
A substrate treating method comprising a step of preparing a semiconductor substrate (W, 11) which has an oxide film (13, 14) containing at least one of a rare earth oxide and an alkaline earth oxide, at least a portion of the oxide film (13, 14) being exposed, and a rinse step of supplying the oxide film (13, 14) on the semiconductor substrate (W, 11) with a rinse liquid made of an alkaline chemical or an organic solvent. Preferably, the alkaline chemical is an alkaline aqueous solution having a pH of more than 7. Further, preferably, the organic solvent is a high concentration organic solvent having a concentration of substantially 100%.