Semiconductor Wafer Temperature Control Segmentation
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Solution Overview
Problem
High-accuracy semiconductor wafer metrology measurements are compromised by temperature variations and heat loads, leading to errors in weight measurements due to convection currents and changes in air density and pressure.
Innovation Solution
The method involves separating the steps of removing the bulk heat load from the semiconductor wafer and equalizing its temperature, using a first temperature changing unit to achieve the majority of the temperature change and a second unit for precise matching to the desired processing temperature, thereby reducing the heat load on the second unit and improving temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature changing unit is used to cool the semiconductor wafer to the desired temperature, then the temperature control can be simplified, but the heat load on the unit becomes excessive causing temperature instability and measurement errors
Solution Approach 1:
The temperature changing process is divided into two separate stages using two distinct temperature changing units. The first unit handles the bulk heat load removal, while the second unit performs precise temperature matching. This segmentation resolves the contradiction by distributing the thermal control functions, preventing any single unit from being overloaded and causing instability.
Solution Approach 2:
The first temperature changing unit performs preliminary cooling to remove the majority of the heat load from the semiconductor wafer before it enters the measurement chamber. This preliminary action reduces the thermal burden on the second unit and the measurement environment, thereby improving measurement precision while maintaining system simplicity.
2Productivity
If the semiconductor wafer is cooled rapidly to reduce measurement time, then productivity increases, but temperature uniformity deteriorates causing measurement errors
Solution Approach 1:
The cooling process is segmented into rapid bulk cooling by the first unit followed by controlled precision cooling by the second unit. This allows the system to achieve both rapid temperature reduction (improving productivity) and fine temperature uniformity control (maintaining measurement accuracy) by separating the aggressive cooling phase from the precision matching phase.
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 enhances the accuracy of weight measurements by minimizing temperature-related errors, allowing for precise temperature control and consistent measurement outcomes, even with high-temperature semiconductor wafers.
Implementation Method 1
removing the bulk heat load from the semiconductor wafer
Implementation Method 2
equalizing its temperature, using a first temperature changing unit to achieve the majority of the temperature change
Implementation Method 3
weighing device for weighing the semiconductor wafers
Implementation Method 4
errors in the measurement output caused by temperature variations in the semiconductor wafers being measured or in the temperature of the measurement balance may become significant
Implementation Method 5
the air in the measurement enclosure may be heated, changing its density and pressure and therefore the buoyancy force exerted on the semiconductor wafer by the air
Data Source
Figure 1~2
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AI summary
A semiconductor wafer processing method comprising controlling the temperature of a semiconductor wafer to be within a predetermined processing temperature range by: causing a first temperature change of the semiconductor wafer using a first temperature changing unit; and subsequently causing a second temperature change using a second temperature changing unit; wherein the first change is greater than the second change; and subsequently loading the semiconductor wafer on a processing area of a semiconductor wafer processing apparatus. Also, a semiconductor wafer processing method comprising controlling the temperature of a semiconductor wafer to be within a predetermined processing temperature range by causing a temperature change of the semiconductor wafer using a temperature changing unit; transporting the semiconductor wafer from the temperature changing unit to a processing area of a semiconductor wafer processing apparatus; and controlling the temperature of the semiconductor wafer during the transporting step.