Silsesquioxane Resin Systems with Base Additives
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Solution Overview
Problem
The development of silicon-containing resins for bilayer resist compositions in photolithographic applications faces challenges such as low thermal stability, pattern collapse, and silicon outgassing, particularly at 193 nm and 157 nm wavelengths, which affect etch resistance, sensitivity, and shelf life.
Innovation Solution
Silsesquioxane-based compositions incorporating HSiO3/2 and RSiO3/2 units with acid-dissociable groups, along with 7-diethylamino-4-methylcoumarin, which enhance thermal stability, etch resistance, and transparency, while minimizing outgassing and improving shelf life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high silicon content is incorporated into the polymer to increase etch resistance, then etch resistance is improved, but thermal stability deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the silsesquioxane resin by incorporating specific functional groups (carboxyl, hydroxyl, amine) at controlled positions and concentrations. This allows optimization of both etch resistance through silicon content and thermal stability through molecular structure modification, resolving the contradiction between these two properties
Solution Approach 2:
The patent creates composite resin systems by combining silsesquioxane backbone with various functional groups and additives (base quenchers, photo-acid generators). This composite approach enables simultaneous achievement of high etch resistance from the silicon network and improved thermal stability from the functional group modifications
2Strength
If silicon-containing components are used to provide etch resistance, then etch resistance is improved, but outgassing increases
Solution Approach 1:
The patent extracts and removes excess silicon content beyond what is necessary for achieving adequate etch resistance. By optimizing the silicon concentration and using alternative etch resistance mechanisms through functional group modification, the patent reduces silicon outgassing while maintaining sufficient etch protection
Solution Approach 2:
The patent employs volatile base quenchers and photo-acid generators that are intentionally designed to be consumed or decomposed during processing. These additives fulfill their function temporarily and are removed, preventing long-term outgassing issues while enabling the silicon-containing resin to achieve necessary performance
3Adaptability or versatility
If base quenchers and photo-acid generators are added to the resin formulation, then photoresist functionality is improved, but shelf-life deteriorates
Solution Approach 1:
The patent introduces stabilizing intermediaries such as antioxidants and moisture scavengers that protect the sensitive photoresist components from degradation. These intermediaries mediate between the reactive base quenchers and photo-acid generators, preventing premature reactions while maintaining shelf-life
Solution Approach 2:
The patent incorporates stabilizing additives and protective formulations in advance that prevent degradation before it occurs. These preemptive measures cushion the sensitive photoresist components against environmental factors and self-degradation, extending shelf-life while maintaining full functionality
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 silsesquioxane-based compositions provide superior etch resistance, high sensitivity, and extended shelf life, addressing the limitations of existing silicon-containing resins by stabilizing the resin structure and improving processing latitude.
Implementation Method 1
the higher the silicon content (wt %) in a silicon-containing resist the higher the etch resistance
Implementation Method 2
The 7-diethylamino-4-methylcoumarin stabilizes the silsesquioxane resin resulting in extended shelf life
Implementation Method 3
Due to its unique structure and high content of Si—H bonds, hydrogen silsesquioxane (HSQ) is remarkably transparent at 193 nm and 157 nm
Implementation Method 4
a silsesquioxane resin having the general formula (HSiO3/2)a(RSiO3/2)b where R is an acid dissociable group
Data Source
AI summary
A silsesquioxane-based composition that contains (a) silsesquioxane resins that contain HSiO3/2 units and RSiO3/2 units wherein; R is an acid dissociable group, and (b) 7-diethylamino-4-methylcoumarin. The silsesquioxane-based compositions are useful as positive resist compositions in forming patterned features on substrate, particularly useful for multi-layer layer (i.e. bilayer) 193 nm & 157 nm photolithographic applications.