Stimulus-Responsive Polymer Bracing for HAR Feature Collapse
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Solution Overview
Problem
Semiconductor fabrication faces challenges with airborne molecular contaminants (AMCs) and capillary forces during drying processes, leading to feature collapse and stiction in high aspect ratio (HAR) structures, which degrade device yield.
Innovation Solution
The use of a stimulus responsive polymer (SRP) film with a ceiling temperature between −80° C. and 400° C., applied to substrates with HAR structures, which are then baked above the glass transition temperature but below the degradation temperature of the SRP, to straighten the HAR structures and prevent collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high aspect ratio structures are used to achieve desired device performance, then device performance is improved, but capillary forces during drying cause feature collapse and stiction
Solution Approach 1:
The patent applies a protective coating to the high aspect ratio structures before the drying process. This preliminary action prevents the capillary forces during drying from causing feature collapse and stiction, thereby maintaining feature stability while achieving the desired device performance
Solution Approach 2:
The patent modifies the surface properties of the structures by applying a protective coating that changes the contact angle and surface tension characteristics. This parameter change reduces the capillary forces generated during drying, preventing feature collapse while maintaining the high aspect ratio structure integrity
2Ease of manufacture
If wet processes are used for etch and clean, then manufacturing capability is improved, but capillary forces during drying cause feature collapse
Solution Approach 1:
The patent applies a protective coating specifically to the high aspect ratio features that are susceptible to capillary forces. This localized treatment provides针对性的 protection during the drying process while maintaining the effectiveness of wet etch and clean processes for manufacturing capability
Solution Approach 2:
The protective coating is applied before the wet processes and drying steps, providing preliminary protection that allows wet manufacturing processes to be used effectively while preventing the harmful capillary effects during subsequent drying
3Reliability
If substrates are stored in nitrogen-filled storage cassettes to protect from AMCs, then surface protection is improved, but process complexity and cost increase
Solution Approach 1:
The protective coating applied to the substrate surfaces provides self-service protection against airborne molecular contaminants. This eliminates the need for complex nitrogen-filled storage cassettes and associated handling procedures, reducing process complexity while maintaining surface protection and reliability
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 SRP film effectively braces HAR structures, preventing feature collapse and stiction, while allowing for controlled removal of the film without damaging the substrate, thus enhancing device yield and reliability.
Implementation Method 1
baking the SRP film at a baking temperature, wherein the baking temperature is above a glass transition temperature the SRP film and below a degradation temperature of the SRP
Implementation Method 2
removing the SRP film comprises exposing the SRP film to a stimulus depolymerize the SRP film. Examples of stimuli include heat, UV radiation, acidic vapor, and noble gas plasma
Data Source
AI summary
Methods of bracing high aspect ratio (HAR) structures include coating the HAR structures with stimulus responsive polymers (SRP) films followed by baking the SRP films at a temperature above the glass transition temperature (Tg) of the SRP film and below the degradation temperature of the SRP. In some embodiments, the SRP film includes a plasticizer.