Method and apparatus for light-irradiation heat treatment
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Solution Overview
Problem
In flash-lamp annealing processes for semiconductor wafers, temperature history equalization across multiple wafers in a lot is challenging, leading to inconsistent treatment and potential wafer bending due to temperature differences between the susceptor and wafers, necessitating the use of dummy wafers for preheating, which reduces efficiency.
Innovation Solution
A heat treatment method and apparatus that preheats the chamber structure using heated treatment gas before initiating the process, ensuring all wafers are treated at a consistent temperature without the need for dummy wafers, by supplying high-temperature gas to raise the susceptor temperature to a stable level before starting the treatment of the initial wafer in a lot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If flash-lamp annealing is performed without preheating the chamber structure, then the treatment time is reduced, but the temperature history becomes inconsistent across multiple wafers in a lot
Solution Approach 1:
The chamber structure is preheated to the treatment temperature before the actual wafer treatment begins. This preliminary action ensures that when wafers are subsequently treated, the chamber structure is already at the correct temperature, eliminating temperature history inconsistencies without requiring dummy wafers.
2Manufacturing precision
If dummy wafers are used to preheat the chamber structure, then temperature history equalization is achieved, but the productivity decreases due to consumption of dummy wafers
Solution Approach 1:
The chamber structure serves its own preheating function by being directly heated to the treatment temperature before wafer processing. This eliminates the need for dummy wafers to perform the preheating function, as the system prepares itself independently, thereby maintaining productivity while achieving temperature history equalization.
3Ease of operation
If the chamber structure is at room temperature during wafer treatment, then the apparatus can start operation immediately, but wafer bending occurs due to temperature differences
Solution Approach 1:
The chamber structure undergoes preliminary heating to match the treatment temperature before wafers are introduced. This preheating action prevents temperature differences between the chamber structure and wafers during treatment, eliminating thermal stress-induced wafer bending while maintaining operational readiness.
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 ensures uniform temperature history for all wafers in a lot, preventing wafer bending and eliminating the need for dummy wafers, thereby enhancing the operational efficiency of the annealing process.
Implementation Method 1
a gas heater that heats the treatment gas supplied from the gas supply part to the chamber
Implementation Method 2
supplying heated treatment gas into the chamber to raise the temperature of a structure inside the chamber
Implementation Method 3
supplying heated treatment gas into the chamber
Implementation Method 4
irradiating the surface of a semiconductor wafer with flash light so that the temperature of only the surface of the semiconductor wafer that is doped with impurities is raised
Implementation Method 5
the temperature of the semiconductor wafer is raised to a desired treatment temperature by pulse heating with flash lamps
Data Source
AI summary
Light is applied for preheating from a halogen lamp to a lower surface of a semiconductor wafer supported on a susceptor within a chamber. Thereafter, flash light is applied for flash heating from a flash lamp to an upper surface of the semiconductor wafer. High-temperature treatment gas heated by a heater is supplied into the chamber to preheat a structure inside the chamber including a susceptor before heat treatment for an initial semiconductor wafer of a lot starts. By raising the temperature of the structure inside the chamber to a temperature substantially equivalent to a temperature of the structure during steady treatment, all semiconductor wafers constituting the lot are supportable on the susceptor maintained at a constant temperature without the necessity of dummy running. Accordingly, a temperature history is equalized for all the semiconductor wafers.