Sacrificial Layer Top Removal for Precise Film Thickness Control
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Solution Overview
Problem
The existing methods for removing the upper part of a sacrificial layer in semiconductor manufacturing face challenges such as achieving precise film thickness, controlling thickness and depth, reducing variations, minimizing substrate damage, improving filling properties, and increasing manufacturing yield and efficiency.
Innovation Solution
A method involving the application of a sacrificial solution containing a polymer with an acid-dissociable protective group and a solvent, followed by contact with an acidic aqueous solution and a remover, to accurately remove the upper part of the sacrificial layer, thereby controlling film thickness and depth, and enhancing substrate processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etch back is performed by dry etching or wet etching to obtain desired film thickness, then film thickness accuracy is improved, but processing time increases
Solution Approach 1:
The sacrificial layer is formed with a predetermined thickness that is intentionally greater than the final desired thickness. This preliminary over-formation allows subsequent selective removal to achieve the exact target thickness, eliminating the need for time-consuming iterative etching processes while maintaining high precision.
Solution Approach 2:
The upper part of the sacrificial layer is selectively removed through contact with acidic aqueous solution followed by remover application. This extraction of the excess portion enables precise thickness control without requiring extended processing times associated with conventional etching methods.
2Manufacturing precision
If the sacrificial film is made highly resistant to etching or the type/concentration of chemical solution is optimized to reduce etching rate, then film thickness accuracy after etching back is improved, but processing time increases
Solution Approach 1:
The invention changes the chemical parameters of the sacrificial layer by using a polymer with acid-dissociable protective groups. This parameter change enables selective removal through acid treatment followed by remover application, achieving precise thickness control without requiring highly resistant materials that would extend processing time.
3Manufacturing precision
If the upper part of the sacrificial layer is removed to achieve desired film thickness, then film thickness control is improved, but variation in thickness and depth of removed upper part increases
Solution Approach 1:
The two-step removal process provides inherent feedback control. The acidic aqueous solution treatment first modifies the upper part of the sacrificial layer, and then the remover selectively removes the modified portion. This sequential approach allows precise control and minimizes variation in the removed thickness and depth, ensuring consistent results.
Solution Approach 2:
The removal process is segmented into two distinct stages: (1) treatment with acidic aqueous solution to modify the upper part, and (2) application of remover to selectively remove the modified portion. This segmentation enables better control over the removal process, reducing variations in thickness and depth compared to single-step methods.
4Productivity
If conventional methods are used to remove the upper part of the sacrificial layer, then manufacturing process is maintained, but substrate damage occurs
Solution Approach 1:
The acidic aqueous solution acts as an intermediary that selectively modifies the upper part of the sacrificial layer without directly contacting or damaging the substrate. This intermediary treatment enables subsequent selective removal while protecting the substrate from damage, maintaining manufacturing efficiency without harmful side effects.
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 method allows for precise control of film thickness and depth, reduces substrate damage, improves filling properties, and increases manufacturing yield and efficiency by accurately removing the sacrificial layer, leading to better electrical characteristics and simplified device manufacturing processes.
Implementation Method 1
a polymer having an acid-dissociable protective group (A)
Implementation Method 2
subjecting an acidic aqueous solution to contact with the surface of the sacrificial layer
Implementation Method 3
applying a remover to the sacrificial layer
Data Source
AI summary
[Problem] To provide a method for removing the upper part of a sacrificial layer. [Means for Solution] A method for removing the upper part of a sacrificial layer comprising the following steps: ·(1) applying a sacrificial solution comprising a polymer having an acid-dissociable protective group (A) and a solvent (B) above a substrate; ·(2) forming a sacrificial layer from the applied sacrificial solution; ·(3) subjecting an acidic aqueous solution to contact with the surface of the sacrificial layer; and ·(4) applying a remover to the sacrificial layer.