EFEM Pre-baking Station for Semiconductor Wafer Heating
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Solution Overview
Problem
The existing process chamber-based pre-baking and degassing of semiconductor wafers result in reduced wafer run rate and throughput due to inefficient heating at low pressure, requiring longer times to raise and control temperature.
Innovation Solution
A pre-baking station is installed in the EFEM area, operating at atmospheric pressure, with multi-stage heating slots and hot nitrogen injection ports to efficiently heat wafers, and can be universally installed by replacing a cooling station, allowing simultaneous heating of multiple wafers and accelerating degassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pre-baking is conducted in a process chamber under reduced pressure, then the wafer can be pre-baked and degassed in the same chamber, but the heating efficiency is low and the time required is increased
Solution Approach 1:
The invention separates the pre-baking function from the process chamber by introducing a dedicated pre-baking station in the EFEM area. This segmentation allows the process chamber to focus on its primary processing function while the pre-baking station handles moisture removal, thereby reducing the time loss associated with inefficient heating in the process chamber.
Solution Approach 2:
The pre-baking station acts as an intermediary device between the wafer loading and the main processing chamber. It performs the pre-baking operation in atmospheric pressure conditions where heating is efficient, then transfers the pre-baked wafer to the process chamber, thus mediating the time loss problem.
2Adaptability or versatility
If pre-baking is conducted in a process chamber, then degassing can be performed simultaneously, but the wafer run rate decreases due to extended heating time
Solution Approach 1:
The invention segments the pre-baking and processing functions into separate stations. The pre-baking station in the EFEM area handles moisture removal quickly under atmospheric pressure, while the process chamber handles the main processing and degassing. This segmentation eliminates the bottleneck caused by slow heating in the process chamber, thereby improving wafer run rate.
Solution Approach 2:
The pre-baking station performs preliminary moisture removal before the wafer enters the process chamber. This preliminary action reduces the overall processing time by completing the heating and drying steps in advance under more efficient atmospheric pressure conditions, thus improving productivity.
3Quantity of substance
If conventional multi-slot ovens are used for pre-baking, then multiple wafers can be heated simultaneously, but the heating time is still prolonged due to inefficient heat transfer
Solution Approach 1:
The pre-baking station uses a flow of hot nitrogen gas to heat the wafers. This pneumatic heating method is much more efficient than conventional conductive heating in ovens, allowing multiple wafers to be heated simultaneously in a shorter time period while maintaining uniform temperature distribution.
Solution Approach 2:
The invention changes the heating parameter from conventional oven heating to hot gas flow heating. By using hot nitrogen gas that flows directly over the wafer surfaces, the heat transfer efficiency is dramatically improved, reducing the heating period while still allowing multiple wafers to be processed simultaneously.
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 significantly improves wafer run rate and throughput by shortening the heating period and maintaining efficient heating, achieving pre-baking in 240-300 seconds compared to conventional ovens, while maintaining uniform temperature distribution.
Implementation Method 1
hot nitrogen injection ports are provided in the pre-baking station to blow hot nitrogen gas along wafers stored in the pre-baking station
Implementation Method 2
a wafer is sandwiched or inserted between heating media (e.g., heated aluminum plates) so that the wafer is heated from both top and bottom
Data Source
AI summary
A pre-baking apparatus for heating a substrate upstream of a process tool is adapted to be connected to an EFEM (equipment front end module) and includes: a chamber which has a front face with multiple slots arranged in a height direction of the chamber, and which is divided into multiple compartments extending from the multiple slots, respectively, toward a rear end of the chamber for loading and unloading substrates; and a connecting frame for connecting the chamber to the process tool. The multiple compartments are separated from each other by a divider plate and provided with heaters for heating the multiple compartments, and each compartment has a gas injection port for blowing a hot inert gas over the substrate placed therein toward the slot.