AlN Heaters

Semicorex AlN heaters for semiconductor is a device used for heating semiconductor materials. It is mainly made of aluminum nitride ceramic material, has excellent thermal conductivity and high temperature resistance, and can operate stably at high temperatures. The heater usually uses a resistance wire as a heating element. By energizing the resistance wire to heat up, the heat is transferred to the surface of the heater to achieve heating of the semiconductor material. AlN heaters for semiconductor plays an important role in the semiconductor production process and can be used in processes such as crystal growth, annealing, and baking.

In the front-end process (FEOL) of semiconductor manufacturing, various process treatments must be performed on the wafer, especially heating the wafer to a certain temperature, and there are strict requirements, because the uniformity of temperature has a very important influence on the product yield; at the same time, semiconductor equipment must also work in an environment where vacuum, plasma and chemical gases exist, which requires the use of ceramic heaters (Ceramic Heater). Ceramic heaters are important components of semiconductor thin film deposition equipment. They are used in the process chamber and directly contact the wafer to carry and enable the wafer to obtain a stable and uniform process temperature and to react and generate thin films on the wafer surface with high precision.

Thin film deposition equipment for ceramic heaters generally uses ceramic materials based on aluminum nitride (AlN) because of the high temperatures involved. Aluminum nitride has electrical insulation and excellent thermal conductivity; in addition, its thermal expansion coefficient is close to that of silicon, and it has excellent plasma resistance, making it very suitable for use as a semiconductor device component.

AlN heaters include a ceramic base that carries the wafer, and a cylindrical support body that supports it on the back. Inside or on the surface of the ceramic base, in addition to a resistance element (heating layer) for heating, there is also an RF electrode (RF layer). In order to achieve rapid heating and cooling, the thickness of the ceramic base should be thin, but too thin will also reduce rigidity. The support body of the AlN heaters is generally made of a material with a thermal expansion coefficient similar to that of the base, so the support body is often also made of aluminum nitride. The AlN heaters adopt a unique structure of a shaft (shaft) joint bottom to protect the terminals and wires from the effects of plasma and corrosive chemical gases. A heat transfer gas inlet and outlet pipe is provided in the support body to ensure uniform temperature of the heater. The base and the support body are chemically bonded with a bonding layer.

A resistance heating element is buried in the heater base. It is formed by screen printing with conductive paste (tungsten, molybdenum or tantalum) to form a spiral or concentric circle circuit pattern. Of course, metal wire, metal mesh, metal foil, etc. can also be used. When using the screen printing method, two ceramic plates of the same shape are prepared, and the conductive paste is applied to the surface of one of them. Then, it is sintered to form a resistive heating element, and the other ceramic plate is overlapped with the resistive heating element to make a resistor element buried in the base.

The main factors affecting the thermal conductivity of aluminum nitride ceramics are the density of the lattice, oxygen content, powder purity, microstructure, etc., which will affect the thermal conductivity of aluminum nitride ceramics.