Wafer Treatment for Defect-Free Self-Assembled Monolayers
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Solution Overview
Problem
Current selective deposition methods in semiconductor fabrication face challenges in achieving defect-free self-assembled monolayers (SAMs) on dielectric or metal surfaces, leading to potential device yield loss due to nanometer-sized particles and packing defects in SAMs, which affect deposition selectivity and film quality.
Innovation Solution
A method involving a pre-clean process with heating and surface activation, followed by multiple cycles of SAM formation and thermal treatments, to form a well-packed SAM layer on the substrate, ensuring reduced particulate formation and improved selectivity during film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional selective deposition methods are used, then deposition selectivity is achieved, but SAM defects and particulates are generated leading to device yield loss
Solution Approach 1:
The patent applies preliminary action by performing a pre-clean process and surface activation treatment before SAM formation. The substrate is heated to a first temperature to remove contaminants, then exposed to activating agents to create a clean, reactive surface that promotes defect-free SAM formation, thereby preventing harmful defects before they can form during the deposition process.
Solution Approach 2:
The patent employs parameter changes by controlling substrate temperature through multiple heating and cooling cycles. The substrate is heated to a first temperature during pre-clean, cooled to a second temperature for SAM formation, and then heated to a third temperature for surface reactivation. These temperature parameter changes optimize each process step to minimize SAM defects and particulate formation.
2Manufacturing precision
If multiple SAM formation cycles are performed, then SAM quality and packing density are improved, but processing time and complexity increase
Solution Approach 1:
The patent applies periodic action by implementing multiple cyclic SAM formation processes. Each cycle consists of exposing the substrate to SAM molecules, heating to a third temperature for surface reactivation, and then cooling. These periodic cycles progressively improve SAM packing quality and reduce defects, with each cycle building upon the previous one to achieve high-quality monolayers.
Solution Approach 2:
The patent maintains continuity of useful action by performing SAM formation cycles without breaking vacuum or exposing the substrate to ambient conditions. The entire multi-cycle process occurs in a continuous vacuum environment, eliminating idle time between cycles and maintaining the beneficial vacuum state throughout the extended processing required for high-quality SAM formation.
3Ease of manufacture
If substrate heating is applied during pre-clean, then contaminant removal and surface activation are enhanced, but thermal damage or unwanted reactions may occur
Solution Approach 1:
The patent applies dynamics by implementing time-dependent temperature control with distinct heating and cooling phases. The substrate is heated to a first temperature for contaminant removal, then cooled to a second temperature for SAM formation, and subsequently heated to a third temperature for reactivation. This dynamic temperature profile optimizes each process step while preventing thermal damage through controlled exposure times and appropriate temperature selection.
Solution Approach 2:
The patent applies local quality by targeting different temperature conditions to different process objectives. The pre-clean uses high temperature for contaminant removal, the SAM formation uses lower temperature to prevent thermal damage while enabling molecular assembly, and the reactivation uses elevated temperature to restore surface functionality. Each temperature regime is locally optimized for its specific purpose.
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 enables the formation of high-quality, defect-free SAMs, enhancing the selectivity of film deposition and reducing the risk of electrical shorts or device failures by minimizing surface defects and particulates, thereby improving the yield and reliability of semiconductor devices.
Implementation Method 1
heating the substrate to a first temperature
Implementation Method 2
promote formation of a self-assembled monolayer (SAM) on the exposed first material
Implementation Method 3
heating the substrate and reactivation of the surface
Data Source
AI summary
Methods of depositing a film selectively onto a first material relative to a second material are described. The substrate is pre-cleaned by heating the substrate to a first temperature, cleaning contaminants from the substrate and activating the first surface to promote formation of a self-assembled monolayer (SAM) on the first material. A SAM is formed on the first material by repeated cycles of SAM molecule exposure, heating and reactivation of the first material. A final exposure to the SAM molecules is performed prior to selectively depositing a film on the second material. Apparatus to perform the selective deposition are also described.