Polysilazane Insulating Film Curing via UV Dangling Bonds
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Solution Overview
Problem
Current methods for forming silicon-oxide-containing insulating films face challenges in achieving good film quality and embeddability, particularly in narrow trenches, due to limitations in curing temperature and film strength, which complicates semiconductor device manufacturing.
Innovation Solution
A method involving the application of a coating liquid containing precursors, solvent volatilization, energy supply under low oxygen conditions to form dangling bonds, and subsequent curing at a lower temperature to enhance crosslinking, allowing for the formation of a dense and strong insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating liquid is applied and cured at high temperature (600-800°C) to increase film strength, then the insulating film strength is improved, but the thermal history increases causing Cu wiring migration and diffusion
Solution Approach 1:
The patent applies preliminary action by performing solvent volatilization and energy supply to form dangling bonds before the curing process. This preliminary treatment prepares the coating film structure in advance, enabling crosslinking to occur at lower temperatures (450°C or below) while still achieving sufficient film strength, thereby avoiding Cu wiring migration and diffusion that occur at high curing temperatures
Solution Approach 2:
The patent changes the curing temperature parameter from the conventional 600-800°C range to 450°C or below. This parameter change is made possible by the preliminary energy supply step that creates dangling bonds, which then react with water during curing to form crosslinked structures at lower temperatures, resolving the contradiction between achieving film strength and avoiding thermal damage to Cu wiring
2Stability of the object's composition
If plasma CVD method is used to form dense insulating film with good film quality, then the film density is improved, but the embeddability in narrow trenches deteriorates
Solution Approach 1:
The patent replaces the plasma CVD mechanical deposition system with a chemical coating system. By applying a coating liquid containing precursors and using solvent volatilization followed by energy supply and curing, the method achieves both good embeddability in narrow trenches (due to liquid flow properties) and high film density (through crosslinking reaction), resolving the contradiction between these two properties
Solution Approach 2:
The patent uses a composite approach by combining organic precursors with inorganic oxide formation. The coating liquid contains precursors that form organic-inorganic hybrid structures during curing, achieving both the embeddability of liquid application and the density of inorganic oxide films, thus resolving the contradiction between ease of manufacture and film stability
3Ease of manufacture
If coating liquid is applied to achieve good embeddability in narrow patterns, then the embeddability is improved, but the insulating film strength deteriorates due to low crosslinking rate
Solution Approach 1:
The patent applies preliminary action by supplying energy to the coating film before curing to form dangling bonds. This preliminary step activates the precursors and creates reactive sites that will form crosslinks during curing, ensuring high film strength even when the coating liquid is applied in a manner that prioritizes embeddability
Solution Approach 2:
The patent introduces water as an intermediary that mediates the crosslinking reaction. The dangling bonds formed by energy supply react with water during curing to form hydroxyl groups and crosslinked structures. This intermediary mechanism enables high crosslinking rate and film strength regardless of the initial coating method, resolving the contradiction between embeddability and film strength
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 enables the production of a dense and high-quality insulating film with improved crosslinking rate and strength, even at lower curing temperatures, suitable for semiconductor manufacturing without the need for high-temperature processing.
Implementation Method 1
a solvent volatilization process of volatilizing a solvent in the coating film
Implementation Method 2
an energy supply process of supplying, after the solvent volatilization process, an energy to the coating film under a low oxygen atmosphere having an oxygen concentration lower than that of atmospheric atmosphere, such that dangling bonds are formed in molecular groups constituting the precursors
Implementation Method 3
subsequently, a curing process of heating the substrate such that the precursors are crosslinked to form the insulating film
Data Source
AI summary
A technique for obtaining good film quality in forming a silicon-oxide-containing insulating film as a coating film on a substrate. A coating liquid containing polysilazane is applied to a wafer, a solvent in the coating liquid is volatilized, and then the coating film is irradiated with ultraviolet rays under a nitrogen atmosphere before performing a curing process. Thus, dangling bonds are likely to be formed at hydrolyzed portions in polysilazane. Since dangling bonds are formed in advance at portions in silicon to be hydrolyzed, productivity of hydroxyl groups is enhanced. That is, since an energy required for hydrolysis is reduced, the number of the portions remaining without being hydrolyzed is reduced even when the curing process is performed at a low temperature. Therefore, dehydration synthesis occurs efficiently, which increases a crosslinking rate and makes it possible to form a dense (good film quality) insulating film.