Siloxane Film Composition Viscosity Stability
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Solution Overview
Problem
Conventional film-forming compositions used in semiconductor manufacturing, particularly for solar cells, face issues with high viscosity changes over time, leading to instability in coating thickness and pattern accuracy during spin coating and ink-jet printing, which affects the formation of impurity diffusion layers and increases costs and environmental impact.
Innovation Solution
A film-forming composition comprising a siloxane polymer with a specific molecular weight and SiO2-converted mass ratio, made from tetra-functional and tri-functional alkoxysilane condensation products, along with an organic solvent, is developed to maintain stability and prevent viscosity increases, ensuring consistent pattern formation and reduced waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional film-forming composition is used, then the coating process can be performed, but the viscosity increases over time leading to poor storage stability and inconsistent coating thickness
Solution Approach 1:
The patent modifies the chemical composition parameters of the film-forming composition by incorporating specific additives and adjusting the ratio of solvents to formants. These parameter changes prevent viscosity increase over time, thereby improving storage stability while maintaining consistent coating thickness during the coating process.
2Ease of manufacture
If spin coating method is used, then film formation can be achieved, but the amount of coating liquid used is large increasing cost and waste liquid
Solution Approach 1:
The patent optimizes the rheological parameters of the coating liquid by adjusting viscosity and surface tension through specific additive combinations. This enables the coating liquid to form uniform films with reduced material consumption, thereby reducing waste while maintaining ease of manufacture through conventional coating methods.
3Loss of substance
If ink-jet method is used for partial diffusion, then the amount of liquid used is reduced, but the discharge stability from nozzle is affected by viscosity changes
Solution Approach 1:
The patent carefully adjusts the viscosity parameter of the coating liquid to a specific range that ensures stable discharge from ink-jet nozzles while minimizing the amount of liquid used. Additives are incorporated to maintain this optimal viscosity range over time, ensuring discharge stability for precise partial diffusion patterning.
Solution Approach 2:
The patent implements quality control measures that monitor viscosity and other critical parameters of the coating liquid. Based on this feedback, adjustments are made to maintain optimal discharge stability from the ink-jet nozzle, ensuring consistent patterning quality while minimizing material usage.
4Manufacturing precision
If photolithography method is used for partial diffusion, then pattern formation is achieved, but the number of steps increases
Solution Approach 1:
The patent combines the film-forming and patterning functions into a single coating step using ink-jet technology. The coating liquid is formulated to self-pattern or be selectively deposited directly in the desired diffusion regions, merging what would traditionally require separate photolithography and coating steps, thereby reducing the total number of manufacturing steps while maintaining pattern formation accuracy.
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 composition enhances storage stability, maintains pattern accuracy, and reduces waste, thereby improving the efficiency and cost-effectiveness of semiconductor manufacturing processes.
Implementation Method 1
a siloxane polymer (A) containing a condensation product (A1) made from a starting material, which is an alkoxysilane containing a tetra-functional alkoxysilane, and a condensation product (A2) made from a starting material, which is an alkoxysilane
Data Source
AI summary
A film-forming composition according to one embodiment includes a siloxane polymer (A) containing a condensation product (A1) and a condensation product (A2). In the (A), a contained amount of the (A1) is 75 percent or less by mass in terms of SiO2 with respect to the total of the (A1) and the (A2). The (A) has a weight-average molecular weight (MW) of 80 percent or greater of a molecular weight value M determined by expression (1) if RA1>RA2, expression (2) if RA1<RA2, or expression (3) if RA1═RA2:M=(RA1/RA2)*(MA1+MA2)+[(RA2−RA1)/RA2)]MA2 expression (1):M=(RA1/RA2)*(MA1+MA2)+[(RA2−RA1)/RA2)]MA2 expression (2):M=MA1+MA2 expression (3):(MA1 and RA1 are MW and the SiO2-converted-mass ratio in the (A), respectively, for the (A1). MA2 and RA2 are MW and the SiO2-converted-mass ratio in the (A), respectively, for the (A2)).