BARC Crust Layer Protection During Contact Metal 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 semiconductor devices, such as FinFETs, which can lead to increased complexity and costs.
Innovation Solution
A method is introduced that involves forming a specially treated crust layer on a bottom anti-reflective coating (BARC) layer using implantation, which prevents unwanted metal loss during wet etching by creating a protective barrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching operations are performed to remove unwanted metal layers, then the metal layer can be patterned and excess metal removed, but unwanted metal loss occurs leading to reduced manufacturing precision
Solution Approach 1:
A crust layer is formed as an intermediary protective barrier between the wet etchant and the metal layer. This crust layer, created through ion implantation into a BARC layer, selectively protects the metal layer from unwanted etching while allowing the etchant to remove excess metal in controlled areas. The crust layer acts as a mediator that enables the etching process to proceed without causing metal loss.
Solution Approach 2:
The crust layer is formed in advance through ion implantation before the wet etching operation. This preliminary action creates a protective barrier that prevents metal loss during the subsequent etching process. The BARC layer is first deposited, then ion implantation creates the crust layer with modified properties that provide etch resistance, preparing the structure for the upcoming wet etching step.
2Manufacturing precision
If ion implantation is used to form a crust layer for protection, then metal loss during wet etching is reduced, but the process complexity increases
Solution Approach 1:
The formation of the protective crust layer is merged with the existing BARC layer deposition process. Instead of adding a separate protection step, the ion implantation is performed on the BARC layer that is already part of the standard fabrication sequence. This combines the protective function with an existing process layer, reducing overall process complexity while maintaining metal layer protection.
3Manufacturing precision
If a crust layer is formed through ion implantation, then unwanted metal loss is prevented, but the manufacturing time increases
Solution Approach 1:
The ion implantation process that forms the crust layer is performed continuously as part of the existing fabrication sequence, immediately following BARC layer deposition. The process flow is designed to maintain continuity, with the crust layer formation seamlessly integrated into the wet etching preparation steps. This eliminates idle time and ensures that the protective layer is formed without interrupting the overall manufacturing rhythm.
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 described method effectively reduces or eliminates unwanted metal loss during wet etching, maintaining the integrity of the metal layer and improving the efficiency of the semiconductor fabrication process.
Implementation Method 1
forming a crust layer on a bottom anti-reflective coating (BARC) layer using implantation
Implementation Method 2
removing unwanted metal layer sections using wet etching operations
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.