Silicon wafers are the foundation of semiconductor devices that power nearly every piece of electronic equipment we use. They have been used for decades in the production of other electronic circuitry because they’re cheap to produce and reliable, but their industry is growing rapidly. They have found many different applications across different industries and scientific fields such as computational science, medical instrumentation, and much more
Silicon Wafer Preparation & Tube furnace
Silicon wafer production is, of course, a necessity for microchip R&D. In laboratory settings, one common technique is dry oxidation. Tube furnaces are used in preparing silicon wafers for various applications, including semiconductors, solar cells, and integrated circuits. The process of silicon wafer preparation involves several steps, including:
Growing a silicon boule. A silicon boule is a large, cylindrical crystal of silicon used as the starting material for silicon wafers. The boule is grown by the Czochralski method, which involves melting a silicon ingot and then slowly withdrawing a cylindrical crystal from the melt.
Slicing the boule. Once the boule is grown, it is sliced into thin wafers. The wafers are typically 1 mm (about 0.04 in) thick and have a diameter of 100-300 mm.
Wafer oxidation. The wafers are then oxidized in a tube furnace. This process creates a thin layer of silicon dioxide on the surface of the wafers. Wafer oxidation is a delicate process that requires painstakingly slow heating to a final temperature of 800°–1200° C. The silicon dioxide layer is necessary to protect the wafers from oxidation and contamination. The upper end of that range is most often used, but the lower end yields thinner and more stable oxides.
Dopant diffusion. In some cases, dopants are diffused into the wafers to create semiconductor devices. The dopants are introduced into the wafers in a tube furnace at high temperatures.
Annealing. The wafers are then annealed in a tube furnace to improve their electrical properties. The annealing process involves heating the wafers to a high temperature and then slowly cooling them down.
Tube furnaces are used for these steps in silicon wafers processing. The Lab furnaces must be able to maintain precise temperatures and atmospheres, as even minor changes can have a significant impact on the quality of the wafers.
Here are some of the benefits of using tube furnaces for silicon wafer preparation:
* Precise temperature control, which is essential for the delicate processes involved in wafer preparation.
* They can be used to create a variety of atmospheres, which is necessary for different steps in the process.
* They are relatively easy to operate and maintain.
Tube furnaces are the most common type of furnace used for silicon wafer preparation. It typically demands a horizontal tube furnace for precise temperature and atmospheric control under extremely high heat.
Ai Furnaces Tube Furnace Design Considerations
As per the target temperature, it’s critical to ramp up by as little as a few degrees per minute. More aggressive heating is liable to create a temperature differential that warps or cracks the wafer, rendering it useless.
Across International Horzianral tube furnace mitigates this risk with two key features: multiple hot zones and automatic sliding. Three zones of 200 mm in length, users can maximize throughput by setting a single temperature across 600 mm, or maximize ramp rate precision by setting a temperature gradient.
In both case, the hot zones are managed by a programmable controller. This allows for countless and perfectly repeatable combinations of heating rates and holding times. If you need support for set-up and pre-programming all our Tech Engineers can guide you.
Typically, the wafers rest on a carrier known as a boat. The boat, in turn, sits on an arm that a technician can slide slowly into the furnace. That is the primary technique to ensure gradual heating. Unfortunately, it’s cumbersome for the technician (who must continually attend to the wafers while wearing a heavy, heat-resistant glove) and prone to variation.
Tube furnaces are available with an automatic sliding mechanism for consistent, hands-off heat introduction. Combined with independent hot zone programming, this effectively gives unlimited control over every stage of heating.
Each Lab furnace also features proprietary end seals that unlock and open in just a couple steps. They make for quick, easy loading and unloading, unlike others that require disassembling the entire seal and flange.
Why Use Ai Tube Furnace?
Our in-house Tech engineering and production resources are dedicated to custom manufacturing for laboratories and R&D Team.
Microchip labs Common customization Needs
Most laboratories prefer a three-hot-zone configuration with programmable digital controllers, for more granular heat control. IAlso, automatic sliding is a valuable and reliable workflow improvement.
Most significantly, the typical ingot size of 100 mm (for R&D purposes) calls for a tube diameter of 120 mm. But many facilities handle far larger ingots, at which point tube furnaces often become cost prohibitive. Across International is manufacturer to offer three-zone tube furnaces with full customization and support
For top-caliber tube furnace check out AiFurnaces. AiFurnaces is an ISO-certified industry leader in lab equipment manufacturing and distribution, specializing in heat treatment and material processing.
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