Wafer Tray Heating for Native Oxide Sublimation
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Solution Overview
Problem
The presence of native oxide layers on wafer surfaces during integrated circuit fabrication interferes with the formation of desired material layers, leading to defects and adverse electrical performance, necessitating effective pre-cleaning methods to facilitate subsequent deposition processes.
Innovation Solution
A reactor system with a reaction chamber and a wafer tray equipped with a heating element that raises the wafer temperature to a sublimation temperature, allowing for the sublimation of oxide materials and ensuring a clean surface for subsequent material deposition, using a method that involves positioning the wafer on the tray, powering the heating element to increase the temperature, and maintaining the wafer at a temperature conducive to sublimation of the oxide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cleaning methods are used to remove native oxide layers, then the oxide removal effectiveness is limited, but the risk of introducing defects and contamination increases
Solution Approach 1:
The patent utilizes the phase transition of oxide materials from solid to vapor through sublimation. By heating the wafer to a specific temperature range, the native oxide layer directly transitions from solid phase to vapor phase, achieving complete removal without liquid contact that could introduce contamination or defects.
Solution Approach 2:
The invention changes the temperature parameter to achieve oxide removal. By controlling the wafer temperature to a specific range (typically 700-900°C), the oxide layer undergoes sublimation. This parameter-based approach provides precise control over the cleaning process, ensuring complete oxide removal while avoiding conditions that would cause defects.
2Use of energy by moving object
If heating elements are placed within the reaction chamber, then heating efficiency is improved, but the complexity of the reactor system increases
Solution Approach 1:
The patent extracts the heating element from the reaction chamber environment and places it on the wafer tray instead. This relocation simplifies the reactor system by eliminating the need for complex internal heating structures within the chamber, while still achieving efficient heating of the wafer through direct contact with the heated tray.
Solution Approach 2:
The wafer tray serves as an intermediary between the heat source and the wafer. The heating element heats the tray, which then transfers thermal energy to the wafer. This intermediary approach simplifies the overall system architecture while maintaining effective heat transfer to the processing material.
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 effectively removes native oxide layers, providing a high-selectivity pre-clean process that reduces defects and improves electrical performance by ensuring a clean surface for subsequent material deposition, allowing for efficient formation of mono-crystalline silicon layers and other target materials with reduced defect counts.
Implementation Method 1
powering a heating element within the wafer tray to raise a temperature of the wafer tray from a first temperature to a second temperature to cause oxide material on the wafer to undergo sublimation
Data Source
AI summary
A reactor system and related methods are provided which may include a heating element in a wafer tray. The heating element may be used to heat the wafer tray and a substrate or wafer seated on the wafer tray within a reaction chamber assembly, and may be used to cause sublimation of a native oxide of the wafer.