Metal Etching Mask for Aperture Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the manufacturing of integrated circuits, the use of photoresist masks during etching processes often results in residue formation, which can lead to defects and reduce yield, particularly in forming miniaturized features like apertures for electron beam inspection tools, where residues cause scattering and affect the precision of the beam.
Innovation Solution
A method involving the use of a metal layer as an etching mask, with an additional metal layer acting as a shelter material to prevent residue formation, and electrochemical etching to form openings in the base layer, ensuring a clean and precise aperture structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist mask is used during etching process, then pattern transfer is achieved, but residue formation occurs on wafer surface
Solution Approach 1:
A metal layer is introduced as an intermediary between the photoresist mask and the wafer surface. The photoresist patterns are first formed, then a metal layer is deposited over the patterned photoresist. This metal layer serves as the actual etching mask that contacts the wafer, while the photoresist can be removed without leaving residues on the wafer surface. The metal layer transfers the pattern to the wafer through etching processes.
Solution Approach 2:
The etching mask function is segmented into two separate components: the photoresist layer for pattern definition and the metal layer for actual etching protection. This segmentation allows each layer to perform its specific function optimally - the photoresist provides precise pattern formation while the metal layer provides clean etching without organic residue contamination.
2Productivity
If dry etching is used to etch wafer covered by photoresist mask, then etching process is completed, but photoresist hardens and leaves organic residue
Solution Approach 1:
The metal layer acts as a protective intermediary between the dry etching process and the photoresist mask. During dry etching, the metal layer is exposed to the etchant while the photoresist remains protected underneath. The metal layer absorbs the etching damage and can be removed afterward, preventing photoresist hardening and organic residue formation on the wafer surface.
Solution Approach 2:
The metal layer functions as a disposable sacrificial element that protects the photoresist during dry etching. After serving its protective purpose, the metal layer is removed, taking any potential contamination with it, while the photoresist remains intact and can be cleanly removed without leaving organic residues.
3Manufacturing precision
If photoresist is used as etching mask, then pattern transfer is achieved, but yield is reduced due to residues causing defects
Solution Approach 1:
The metal layer serves as an intermediary that enables clean pattern transfer without the yield-reducing side effects of photoresist. By using the metal layer as the actual etching mask that contacts the wafer, the process achieves precise pattern transfer while eliminating organic residue contamination that causes defects and reduces yield.
Solution Approach 2:
The process replaces organic photoresist-based masking with an inorganic metal-based masking system. This substitution eliminates the fundamental problem of organic residue contamination while maintaining the pattern transfer capability, thereby improving manufacturing yield 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
This approach reduces residue formation, enhances the structural integrity and uniformity of the aperture, and improves the precision and reliability of the electron beam inspection by maintaining a clean aperture surface, thereby increasing yield and reducing defects.
Implementation Method 1
forming an opening in the base layer by electrochemical etching
Data Source
AI summary
A method of processing a workpiece may include forming a first layer on a first side of a base layer. The base layer may be part of a substrate including a plurality of layers. The method may also include forming a second layer on the first layer. A material of the second layer may include metal. The method may also include forming an opening in the second layer, forming an opening in the first layer by etching, and removing the second layer. The method may include dry etching of the first layer.