Oxide Films

Alfa Chemistry can provide high-quality thermal oxide on wafers from 50mm to 300mm in size for PVD and CVD applications. We expose silicon wafers to a combination of oxidant and heat to form a silicon dioxide (SiO₂) layer, which is most commonly made of hydrogen and/or oxygen. SiO₂ can grow to a thickness of about 20 Å (Angstrom) on a wafer in ambient air. However, in most cases, thermal oxide growth uses a heat source to catalyze the reaction, thus producing an oxide layer of up to 25000 Å. Thermal oxide wafers have many applications, the main purpose of which is as a dielectric material and in microelectromechanical systems (MEMS) devices.

Alfa Chemistry's Thermal Oxidation Method

Rapid Heat Treatment (RTP)

RTP is usually used on thin dry thermal oxide, or implant annealing applications. In RTP, the wafer will quickly heat up to over 1,000 ℃ in a short time. After a few seconds of exposure, the wafer will slowly cool to room temperature to prevent cracking, resulting in a thin silicon dioxide layer.

Thermal Diffusion

The thermal diffusion of the oxide occurs between about 800°C and 1100 ℃. There are two ways to grow the film: "wet" or "dry".
① Dry oxidation uses oxygen (Si + O₂ → SiO₂).
② Wet oxidation uses steam (Si + 2H₂O → SiO₂ + 2H₂).

Our Oxide Films

Wet Thermal Oxide Films

Wet thermal oxide films are usually grown in quartz tubes under a combination of heating and pure steam. The wet thermal oxide film is usually used as a barrier layer on thick film silicon on the insulator wafer between the handle and the carrier wafer, which is a consumable in chemical mechanical planarization (CMP) for polishing tools and backing plates.

Dry Heat Oxide Films

The silicon dioxide layer caused by dry thermal oxide is much thinner than wet oxide, and the process takes longer. Due to these limitations, the thickness of the dry heat oxide film must not exceed 1 000Å.

Particle-Sensitive Oxide Films

Alfa Chemistry grows this film by wet or dry thermal oxidation of the wafer. To minimize particle contamination, all processing is performed in a clean room, and the starting wafer must have a low particle count (using the original factory packaging).

Applications for Oxide Films

In the manufacture of Si wafers used to manufacture integrated circuits (IC), oxidation is an essential stage. This process provides many benefits, such as electrical isolation between the multilayer interconnection layers of the IC. In addition, oxidation can also provide surface passivation, which can form a barrier against corrosion. Other benefits include preventing the IC from being contaminated by impurities in the substrate.

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