Silicon Seed Layer Formation for Thin Film Thickness Uniformity
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Solution Overview
Problem
As semiconductor integrated circuit devices continue to miniaturize, there is a need for thinner films with higher film quality, particularly in terms of thickness uniformity, which existing methods such as those using disilane gas and amorphous silicon films have not adequately addressed.
Innovation Solution
A method involving the use of aminosilane-based gases and higher-order silane-based gases to form a dual seed layer on a silicon substrate, where silicon from the aminosilane gas is adsorbed and then filled with silicon from higher-order silane gases, enhancing film thickness uniformity through atomic layer deposition and chemical vapor deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If disilane gas is used to form amorphous silicon film with film forming temperature of 530°C or lower and flow rate of 300 cc or higher, then thickness uniformity is improved, but further miniaturization requires even better thickness uniformity that cannot be achieved
Solution Approach 1:
The seed layer formation process is segmented into two distinct stages: first adsorbing silicon from aminosilane-based gas to create initial nucleation sites, then depositing silicon from higher-order silane-based gas to complete the layer. This segmentation allows each stage to optimize for its specific function, achieving superior thickness uniformity of ±1% or better that enables further device miniaturization
Solution Approach 2:
The aminosilane-based gas acts as an intermediary that first adsorbs onto the base to create a preliminary silicon layer, which then serves as a foundation for the subsequent deposition of higher-order silane-based gas. This intermediary step ensures uniform nucleation and prevents direct deposition issues, achieving the required thickness uniformity for miniaturized devices
2Measurement precision
If film thickness is increased to maintain uniformity, then measurement accuracy improves, but thickness uniformity deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the deposition process by using aminosilane-based gas followed by higher-order silane-based gas, rather than relying solely on disilane gas parameters. This parameter change enables the formation of uniform seed layers even at reduced film thicknesses, maintaining both measurement accuracy and thickness uniformity simultaneously
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 significantly improves film thickness uniformity to ±1%, maintaining excellent uniformity even at increased film thicknesses, surpassing the limitations of comparative methods, and allows for the formation of silicon-containing thin films with improved quality.
Implementation Method 1
adsorbing at least silicon included in an aminosilane-based gas on the base
Implementation Method 2
depositing at least silicon included in a higher-order silane-based gas having an order that is equal to or higher than disilane on the base, on which at least the silicon included in the aminosilane-based gas is adsorbed
Data Source
AI summary
Provided is a method of forming a seed layer for forming a thin film, which is capable of further improving a thickness uniformity of the thin film. The method of forming a seed layer that is a seed of the thin film on a base includes adsorbing at least silicon included in an aminosilane-based gas on the base, by using the aminosilane-based gas; and depositing at least silicon included in a higher-order silane-based gas having an order that is equal to or higher than disilane on the base, on which at least the silicon included in the aminosilane-based gas is adsorbed, by using the higher-order silane-based gas having an order that is equal to or higher than the disilane.