Because wafers and substrates are extremely thin, clamping them at the edge as in traditional chucks causes serious bowing, warping and destruction. Common wafer holding technologies include vacuum, electrostatic, mechanical, and magnetic. All wafer chucks provide the necessary clamping uniformity without distortion or damage, regardless of the clamping method being employed.
Ceramic wafer clamps are made of high-purity alumina, zirconia, or silicon carbide, and are superior to conventional metal clamps in the following aspects:
Superior Heat resistance
The manufacture of semiconductor materials may necessitate extremely high temperatures, frequently surpassing 1,000 degrees Celsius. Metal fixtures may distort and lose their grip at these temperatures, resulting in wafer failure and damage. The wafer is kept securely fixed and stable throughout the process thanks to the use of ceramic fixtures, which can maintain their holding strength even at high temperatures.
Highly Resistant to Corrosion and Chemical Degradation
Corrosive gases and chemicals are utilized in the manufacturing of semiconductor materials, which can lead to rust or corrosion of metal fixture, jeopardising their structural integrity and resulting in potential contamination to the wafer. Ceramic materials have been demonstrated to be very resistant to the chemical reactions occur in the semiconductor manufacturing process. As a result, they do not corrode, rust or deteriorate, and leave no residue on the wafer surface, therefore decreasing the possiblity of contamination.
Outstanding Mechanical Strength and Stability
Ceramic clamps are more durable than metal clamps because of the inherent strength and rigidity of ceramic materials. Consequently, they are not readily distorted or damaged by external force, allowing them to provide a uniform and stable clamping force that ensures the wafer is firmly held and reduces the likelihood of movement or damage during processing.
High Thermal Conductivity
Due to the excellent thermal conductivity of the ceramic material employed in these clamps, heat transfer between the wafer and processing tool is improved. This guarantees that the wafer's temperature is regulated throughout the varying processing steps, resulting in consistant results.
Non-Conductive
Because the ceramic material does not conduct electricity, the clamp does not interfere with the electrical properties of the wafer, which is critical in the manufacturing of microchips and other devices. Furthermore, ceramic clamps are a very stable and consistent material since they have a low coefficient of thermal expansion, which means they do not noticeably vary in size or shape when subjected to heat changes.
To fit various types of wafers and processing machinery, ceramic wafer clamps are available in different sizes, shapes, and configurations. UNIPRETEC can do custom development to meet particular requirements and can be compatible with different types of wafer materials including silicon, gallium arsenide, and indium phosphide.
Manufacturing process
The following stages comprise the primary production process of ceramic wafer fixtures:
Raw material preparation
Mix and pre-treat appropriate ceramic powder, like yttrium oxide or alumina powder.
Procedure of molding
The ceramic powder is pressed, injected, or 3D printed into the required form.
Technology around firing
High temperature sintering of the produced ceramic body increases its mechanical strength and density.
Accurate machine work
For the necessary surface smoothness and dimensional precision, the sintered ceramic components are carefully machined by turning, grinding, and milling.
Process of surface
To increase the resulting ceramic components' resistance to wear and corrosion, they are coated with either yttrium oxide or alumina.
Utilisation
In semiconductor fabrication, ceramic wafer fixtures find extensive use. They find principal use in the following categories of equipment:
Electric wafer polisher
It is used to smooth and level silicon wafer surfaces.
Hardware for heat treatment
Internal components of reaction chambers in annealing, diffusion, and oxidation processes.
Computerized photolithography
High accuracy and high stability ceramic components are needed for semiconductor chip photolithography.
Processes for ion implantation, deposition, and etching
For these procedures, the wafer must be protected by high-voltage, high-insulation ceramic fixtures.
Semiconductor processing depends critically on ceramic wafer fixtures. To satisfy the requirements of semiconductor equipment for high-performance ceramic components, their design concepts, material choices, and manufacturing procedures must all be tightly regulated.
