Wafer Surface Preclean and SAM Formation for Selective ALD
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Solution Overview
Problem
Current semiconductor process chambers fail to adequately prepare substrates for selective atomic layer deposition (ALD) after precleaning, leading to inadequate substrate preparation and performance issues in integrated circuits.
Innovation Solution
An integrated preclean chamber system that uses a remote plasma source to remove residues and oxides, followed by the formation of a self-assembled monolayer (SAM) as a blocking layer, utilizing unsaturated carbon-based compounds and alcohols to enhance substrate preparation for reverse selective ALD, ensuring minimal substrate damage and improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion bombardment or radical-based preclean processes are used to remove native oxide and contaminants, then contact resistance is reduced and adhesion is improved, but the substrate surface is not adequately prepared for selective ALD depositions
Solution Approach 1:
The patent combines preclean and SAM formation into a continuous single-chamber process without air breaks, maintaining vacuum conditions throughout. This continuous action ensures the substrate surface remains properly prepared for both oxide removal and subsequent ALD deposition, resolving the contradiction between achieving good contact properties and preparing the surface for selective ALD.
Solution Approach 2:
The invention merges two separate processes (preclean and SAM formation) into a single integrated chamber and process sequence. By combining these steps that were previously performed in separate chambers, the patent achieves both oxide removal for good contact resistance and proper surface preparation for selective ALD, eliminating the need for substrate transfer and air exposure.
2Adaptability or versatility
If multiple separate process chambers are used for precleaning and ALD deposition, then each process can be optimized independently, but substrate transfer between chambers causes air exposure and contamination
Solution Approach 1:
The patent combines preclean and SAM formation chambers into a single integrated vacuum chamber, eliminating the need for substrate transfer between chambers. This merger maintains vacuum conditions throughout the entire process sequence, preventing air exposure and contamination while still allowing independent optimization of each process step through controlled gas delivery and parameter adjustment.
Solution Approach 2:
The continuous vacuum process eliminates interruptions and air exposures that would occur with multiple chamber transfers. The substrate remains in vacuum throughout the entire sequence from preclean through SAM formation, maintaining surface integrity and preventing contamination while allowing each process step to be independently controlled and optimized.
3Productivity
If traditional preclean processes are used without SAM formation, then the process is simpler and faster, but the substrate is not properly prepared for reverse selective ALD deposition
Solution Approach 1:
The patent performs SAM formation as a preliminary step immediately following preclean within the same vacuum chamber. This preliminary action of forming the self-assembled monolayer prepares the substrate surface for reverse selective ALD deposition by creating the appropriate surface chemistry and morphology, ensuring proper deposition control without adding significant process time or complexity.
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 system effectively prepares substrates for selective ALD, reducing contact resistance and enhancing the performance of integrated circuits by providing an integrated solution for metal surface cleaning and modification, thereby improving RC delay and throughput while minimizing costs.
Implementation Method 1
a remote plasma source (RPS) fluidly coupled to the process chamber and configured to produce radicals or ionized gas mixture with radicals that flow into the processing volume to remove residue or oxides from a surface of the substrate
Implementation Method 2
use radicals (generated by remote plasma) to reduce metal with chemical reaction from the substrate
Implementation Method 3
a heating system located in the pedestal and configured to heat a substrate by flowing gas on a backside of the substrate
Implementation Method 4
the heating system is configured to heat the substrate from approximately 60 degrees Celsius to approximately 450 Celsius to reduce oxide on the surface of the substrate
Implementation Method 5
a first gas delivery system configured to provide at least one first chemical into the processing volume to produce a self-assembled monolayer (SAM) on the surface of the substrate
Implementation Method 6
forming a blocking layer with a first chemical from a first ampoule fluidly connected to the process chamber on at least a portion of the surface of the substrate
Data Source
AI summary
Methods and apparatus for processing a substrate include cleaning and self-assembly monolayer (SAM) formation for subsequent reverse selective atomic layer deposition. An apparatus may include a process chamber with a processing volume and a substrate support including a pedestal, a remote plasma source fluidly coupled to the process chamber and configured to produce radicals or ionized gas mixture with radicals that flow into the processing volume to remove residue or oxides from a surface of the substrate, a first gas delivery system with a first ampoule configured to provide at least one first chemical into the processing volume to produce a SAM on the surface of the substrate, a heating system located in the pedestal and configured to heat a substrate by flowing gas on a backside of the substrate, and a vacuum system fluidly coupled to the process chamber and configured to control heating of the substrate.