Electrostatic chuck

Electrostatic chuck is a kind of ultra-clean wafer carrier suitable for vacuum environment or plasma environment. It uses the principle of electrostatic adsorption to carry out flat and uniform clamping of ultra-thin wafer, and is widely used in PVD, PECVD, ETCH, EUVL, ion implantation and other semiconductor manufacturing equipment.

The typical electrostatic chuck holding system is a sandwich structure consisting of three parts: dielectric adsorption layer, electrode layer and base layer, and the three parts are superimposed in a layered structure in the electrostatic chuck from the surface to the base in order to form the dielectric adsorption layer, electrode layer and base layer.

In practical applications, the disc is used as the electrode on the upper surface, and the lower electrode and dielectric are integrated into one component. In the wafer manufacturing process, a DC voltage is applied between the wafer and the lower electrode, and the wafer is clamped to the electrostatic chuck due to electrostatic attraction. In addition, the heat of the disc can be carried out by a heat-conducting gas such as helium flowing through the back of the disc to achieve temperature control.

At present, the electrostatic chuck mainly uses alumina ceramics as the main manufacturing material, and the thermal conductivity and related mechanical properties of alumina materials are not as good as that of aluminum nitride ceramics. However, due to the fact that aluminum nitride ceramic processing technology is much more difficult than aluminum oxide ceramics, aluminum nitride ceramics have not been widely used in the current relatively mature electrostatic chuck technology, most of the electrostatic chuck are made of relatively simple aluminum oxide ceramics as the main material, the use of aluminum nitride ceramics instead of aluminum oxide ceramics as the manufacturing material of electrostatic chuck will become a trend.    

The electrostatic chuck uses alumina or aluminum nitride ceramics and sapphire as the main material, and other conductive substances need to be added in the production process to make its overall resistivity meet the functional requirements, which requires manufacturers to have a deep understanding of the physical characteristics of the material; The interior of the ceramic and the junction of the ceramic layer and the metal layer in the electrostatic chuck require high machining accuracy, which requires manufacturers to master the skills of precision machining. Manufacturers need to have surface treatment capabilities, so that the treated electrostatic chuck has high temperature resistance, wear resistance and other characteristics.

The dielectric layer on the surface of the Coulomb type electrostatic chuck in contact with the wafer is a high-impedance ceramic material. A conductive electrode layer is sandwiched in the ceramic layer. When the electrode is connected to the HVDC power supply, the surface of the dielectric material will generate polarized charge. The charge distributed on the back of the chip is opposite to the charge distributed on the chuck, and the chip will be sucked by the chuck.

When the dielectric layer material used by the electrostatic chuck is a semiconductor material, it is called the Johnsen-Rahbek electrostatic chuck (JR ESC). The dielectric surface not only has a polarized charge, but also a large part of the free charge, which is because the dielectric of the JR chuck has a certain conductivity. Generally speaking, the suction force of JR chuck is larger than that of Coulomb type.

According to GlobaI Info Research data, in 2021 China's coulomb type electrostatic chuck sales accounted for 71.51%, the market size reached 1.462 billion yuan, is expected to reach 2.387 billion yuan in 2022-2028, the compound growth rate of 7.60%. From the perspective of product market application, wafer suppliers account for a relatively large proportion. The main reason is that Applied Materials and Lam Research mainly produce semiconductor equipment, while supporting the production of electrostatic chucks, and electrostatic chucks are bundled equipment sold to wafer manufacturers.

The global electrostatic chuck market is highly monopolistic, dominated by Japanese and American companies, American companies mainly AMAT (Applied materials), LAM (Pan Forest Group), and Japanese companies mainly Shinko (Shinko Electric), TOTO, NTKCERATEC and so on. International giants have long controlled the supply chain of global electrostatic chuck products, and the market concentration is high.

Fountyl Technologies PTE Ltd., is located in Singapore, utilize nearly 20 years of technology accumulation in the semiconductor field and has extensive experience in the design and process of ceramic vacuum chuck, ceramic arms, ceramic square beams, ceramic guides, etc. Based on an established design and process team, Fountyl offers a full range of technical services for advanced ceramic products in the semiconductor field. Excellent equipment condition, excellent equipment capability, and can be multi-process cooperation development, efficient evaluation, high-quality implementation, the whole process collection of experimental data, detailed process management and superior service.