Sacrificial Polymer for Semiconductor Feature Stability
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Solution Overview
Problem
In semiconductor processing, feature toppling due to capillary forces resulting from drying after wet cleaning can lead to defects and render semiconductor devices inoperable.
Innovation Solution
Maintaining the structure in a fully wet state during processing, depositing a polymer solution in openings, and baking it to form a sacrificial polymer material, which prevents drying-induced toppling by using a processing apparatus with dedicated chambers for wet cleaning, baking, and polymer removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet cleaning is performed to remove residue, then cleaning quality is improved, but capillary forces during drying cause feature toppling
Solution Approach 1:
A sacrificial polymer material is deposited as an intermediary substance into the openings between features. This polymer fills the void space and acts as a mediator that prevents capillary forces from forming during drying, thereby eliminating the toppling mechanism while preserving the cleaning benefit
Solution Approach 2:
The sacrificial polymer is deposited into the openings before the drying step occurs. This preliminary action prepares the structure by filling the openings with a material that will prevent capillary forces from forming during the subsequent drying process, thus preventing feature toppling before it can occur
2Reliability
If openings are filled to prevent toppling, then feature stability is improved, but additional processing steps are required
Solution Approach 1:
The sacrificial polymer is deposited into the openings to prevent toppling, then deliberately removed in a subsequent step. This allows the openings to be filled for stability during critical processing, then discarded afterward to restore the original structure without permanent modification
Solution Approach 2:
The sacrificial polymer serves as a temporary, disposable material that is introduced solely for its protective function during a specific processing window, then removed. It is a low-cost, short-lived intermediary that enables the process but is not part of the final device
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
Significantly reduces the likelihood of feature toppling, resulting in fewer defects and ensuring the integrity of semiconductor devices, with an average of less than 0.00015 toppling defects/square micron compared to previous approaches.
Implementation Method 1
baking it to form a sacrificial polymer material
Implementation Method 2
feature toppling due to capillary forces resulting from drying after wet cleaning
Data Source
AI summary
In an example, a wet cleaning process is performed to clean a structure having features and openings between the features while preventing drying of the structure. After performing the wet cleaning process, a polymer solution is deposited in the openings while continuing to prevent any drying of the structure. A sacrificial polymer material is formed in the openings from the polymer solution. The structure may be used in semiconductor devices, such as integrated circuits, memory devices, MEMS, among others.