Metal Layer Protection Using Implanted BARC During Wet Etching
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing unwanted metal loss during wet etching operations in the fabrication of FinFET devices, which complicates the manufacturing process and affects device performance.
Innovation Solution
A method is introduced that forms a crust layer on a bottom anti-reflective coating (BARC) layer using implantation, which protects the metal layer from chemical etchants during wet etching, thereby minimizing metal loss and maintaining the integrity of the metal layer for subsequent source/drain contact formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching operations are performed to remove unwanted metal layer sections, then the metal layer can be patterned for source/drain contact formation, but unwanted metal loss occurs during the etching process
Solution Approach 1:
A crust layer is formed as an intermediary protective layer between the chemical etchant and the metal layer. This crust layer, created through ion implantation into the BARC layer, acts as a mediator that allows the etchant to remove unwanted metal sections while protecting desired metal portions from unwanted loss.
Solution Approach 2:
The crust layer is formed in advance through ion implantation operations before the wet etching process. This preliminary action modifies the BARC layer to create a protective crust that will shield the metal layer during subsequent etching operations, preventing unwanted metal loss while allowing controlled etching where needed.
2Loss of substance
If the metal layer is protected during wet etching, then metal loss is reduced, but the fabrication process complexity increases
Solution Approach 1:
The physical and chemical properties of the BARC layer are changed through ion implantation, transforming it into a crust layer with different etching resistance properties. This parameter change allows the same BARC layer to serve dual functions: as an anti-reflective coating and as a protective crust during etching, without adding separate protective layers.
Solution Approach 2:
The BARC layer is given multiple functions: it serves as both the bottom anti-reflective coating and the protective crust layer during wet etching. By making the BARC layer resistant to chemical etchants through ion implantation, one layer performs multiple protective roles, simplifying the overall fabrication process despite the added implantation step.
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 method effectively reduces or eliminates unwanted metal loss during wet etching, allowing for higher contact resistance and improved device performance by controlling the implant energy and dosage levels to achieve zero or near-zero metal loss, thus simplifying the fabrication process.
Implementation Method 1
forming a crust layer on top of the BARC layer through implantation
Data Source
AI summary
Disclosed is a method of fabricating a contact in a semiconductor device. The method includes: receiving a semiconductor structure having an opening into which the contact is to be formed; forming a metal layer in the opening; forming a bottom anti-reflective coating (BARC) layer in the opening; performing implanting operations with a dopant on the BARC layer and the metal layer, the performing implanting operations including controlling an implant energy level and controlling an implant dosage level to form a crust layer with a desired minimum depth on top of the BARC layer; removing unwanted metal layer sections using wet etching operations, wherein the crust layer and BARC layer protect remaining metal layer sections under the BARC layer from metal loss during the wet etching operations; removing the crust layer and the BARC layer; and forming the contact in the opening over the remaining metal layer sections.