Flash Lamp Wafer Heating With Instant Oxidizing-Gas Supply
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Solution Overview
Problem
Conventional gas control techniques are unable to instantaneously supply large quantities of oxidizing gas during flash irradiation, which is necessary for achieving an oxidation reaction in a peak temperature range during flash lamp annealing, thereby failing to meet the strict demands for oxide film thickness and quality in semiconductor manufacturing.
Innovation Solution
A heat treatment apparatus and method that includes a chamber, a flash lamp for irradiating the substrate with a flash of light, a gas supply part with a storage tank and a supply valve, and an exhaust part to control the pressure in the chamber. The supply valve is opened at a predetermined timing when the pressure in the gas storage part is higher than atmospheric pressure and the chamber pressure is reduced below atmospheric pressure, allowing instantaneous supply of the treatment gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional gas control techniques are used to supply oxidizing gas during flash irradiation, then the gas supply is continuous and controlled, but the gas cannot be supplied instantaneously in large quantities to achieve oxidation reaction in peak temperature range
Solution Approach 1:
The chamber is evacuated to below atmospheric pressure before the flash irradiation begins, and the gas storage part is pressurized in advance. When the supply valve opens during the peak temperature range, the pressure difference immediately drives large quantities of oxidizing gas into the chamber at high speed, achieving instantaneous gas supply that enables oxidation reaction only in the peak temperature range.
Solution Approach 2:
The system changes the pressure parameter dynamically: the chamber pressure is reduced to below atmospheric pressure while the gas storage part pressure is increased to above atmospheric pressure. This creates a large pressure difference that enables instantaneous gas flow when the supply valve opens, solving the contradiction between gas supply speed and oxide film quality.
2Manufacturing precision
If oxidizing gas is supplied instantaneously in large quantities during flash irradiation, then oxidation reaction occurs only in peak temperature range, but conventional gas control techniques cannot achieve such instantaneous gas supply
Solution Approach 1:
The chamber is evacuated to below atmospheric pressure before the flash irradiation begins, and the gas storage part is pressurized in advance. When the supply valve opens during the peak temperature range, the pressure difference immediately drives large quantities of oxidizing gas into the chamber at high speed, achieving instantaneous gas supply that enables oxidation reaction only in the peak temperature range.
Solution Approach 2:
The system uses pneumatic pressure differential to achieve instantaneous gas supply. By maintaining pressure difference between the gas storage part (above atmospheric pressure) and the chamber (below atmospheric pressure), the oxidizing gas flows rapidly into the chamber when the supply valve opens, enabling precise control of oxidation reaction timing without complex control systems.
3Manufacturing precision
If the supply valve is opened during flash irradiation to supply treatment gas, then the oxidation reaction can occur in peak temperature range, but the pressure control must be precise to avoid gas leakage or insufficient supply
Solution Approach 1:
The system changes the pressure parameter dynamically: the chamber pressure is reduced to below atmospheric pressure while the gas storage part pressure is increased to above atmospheric pressure. This creates a large pressure difference that enables instantaneous gas flow when the supply valve opens, solving the contradiction between gas supply speed and oxide film quality.
Solution Approach 2:
The system uses pneumatic pressure differential to achieve instantaneous gas supply. By maintaining pressure difference between the gas storage part (above atmospheric pressure) and the chamber (below atmospheric pressure), the oxidizing gas flows rapidly into the chamber when the supply valve opens, enabling precise control of oxidation reaction timing without complex control systems.
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 solution enables the instantaneous and controlled supply of treatment gas, ensuring that the oxidation reaction occurs only in the peak temperature range during flash irradiation, thereby achieving the desired thickness and quality of oxide films in semiconductor manufacturing.
Implementation Method 1
The wavelength of light emitted from the xenon flash lamps is shorter than that of light emitted from conventional halogen lamps, and approximately coincides with a fundamental absorption band of a silicon semiconductor wafer. Thus, when a semiconductor wafer is irradiated with a flash of light emitted from the xenon flash lamps, the temperature of the semiconductor wafer can be raised rapidly
Implementation Method 2
an exhaust part for exhausting gas from the chamber to reduce the pressure in the chamber; the controller controls the gas supply part and the exhaust part... the pressure in the chamber is reduced to lower than atmospheric pressure
Implementation Method 3
the supply valve is opened at a predetermined timing in such a condition that the pressure in the gas storage part is higher than atmospheric pressure and the pressure in the chamber is reduced to lower than atmospheric pressure. This allows the treatment gas to flow all at once from the gas storage part which is pressurized toward the chamber which is depressurized
Implementation Method 4
it has been necessary to supply the oxidizing gas instantaneously and in large quantities during the flash irradiation... causing an oxidation reaction only in a peak temperature range during flash irradiation
Data Source
AI summary
A semiconductor wafer received in a chamber is preheated by light irradiation from halogen lamps, and is thereafter irradiated with flashes of light from flash lamps. Prior to the flash irradiation, ozone is stored in a gas storage tank, so that the pressure in the gas storage tank is higher than atmospheric pressure. On the other hand, the pressure in the chamber is reduced to lower than atmospheric pressure. In this condition, a supply valve is opened between the time when the flash lamps turn on to start the flash irradiation and the time when the temperature of a front surface of the semiconductor wafer reaches a peak temperature. This allows ozone gas to flow all at once from the gas storage tank toward the chamber, thereby supplying the ozone gas instantaneously into the chamber.