One of the largest challenges faced in the semiconductor manufacturing industry is the surface contamination of silicon wafers. Most commonly, silicon wafers become contaminated simply from exposure to the air, which contains a high degree of organic particle contaminants. These contaminants strongly bond to the silicon wafer surface due to a strong electrostatic force, creating a lot of headache for those in the semiconductor manufacturing industry.
In order to function properly, silicon wafers must be completely free of any contaminants. Removing these contaminants is not the simplest of tasks, however, as silicon wafers are very fragile. For this reason, semiconductor manufacturing businesses must adhere to a carefully formulated cleaning plan that ensures the wafer surfaces are returned to a clean state while maintaining minimal risk of damage.
Price Unit: 1000 PCS (1 KPCS)
Classification of pollutants and impurities
Some organic and inorganic compounds are required in the IC fabrication process. Furthermore, the manufacturing process is always carried out in a clean room with human intervention, resulting in various environmental pollution of the silicon wafer. Pollutants are classified into four categories based on their occurrence: particles, organic matter, metal pollutants, and oxides.
Particles
Polymers, photoresists, and etching impurities make up the majority of the particles. Typically, the particles stick to the silicon surface, impacting the subsequent process' development of geometric features and electrical properties. Although the adhesion between the particles and the surface is diverse, it is primarily van der Waals attraction, thus the particle removal method is primarily to undercut the particles using physical or chemical ways, and gradually remove the particles. The particle's contact area with the silicon surface is reduced, and the particles are eventually removed.
Organics
Human skin oils, clean room air, mechanical oils, silicone vacuum greases, photoresists, cleaning solvents, and other organic contaminants can all be found in the IC process. Each contaminant affects the IC process in a different way, mainly by producing an organic layer on the wafer surface that prevents the cleaning solution from reaching the wafer surface. As a result, removing organic materials is frequently the first step in the cleaning procedure.
Metal contaminants
Metal interconnect materials are utilized to connect separate devices in the IC circuit fabrication process. Photolithography and etching are used to create contact windows on the insulating layer, and then evaporation, sputtering, or chemical vapor deposition are used to create metal interconnects (CVD). To construct interconnect lines, interconnect films such as Al-Si, Cu, and others are etched, and then the deposited dielectric layer is chemical mechanical polished (CMP). This procedure has the potential to contaminate the IC production process. Various metal contaminations are produced while constructing metal interconnects. To remove metal pollution, appropriate steps must be done.
Primary oxides and chemical oxides
In an environment including oxygen and water, silicon atoms are very easily oxidized to create an oxide layer, known as a native oxide layer. Due to the great oxidizing power of hydrogen peroxide, a chemical oxide layer will form on the silicon wafer surface after cleaning with SC-1 and SC-2 solutions. This surface oxide must be removed once the wafer has been cleaned to assure the quality of the gate oxide. Oxides produced by chemical vapor deposition (CVD) in the IC process, such as silicon nitride and silicon dioxide, should also be selectively removed in the cleaning process.
Price Unit: 1000 PCS (1 KPCS)
Classification of pollutants and impurities
Some organic and inorganic compounds are required in the IC fabrication process. Furthermore, the manufacturing process is always carried out in a clean room with human intervention, resulting in various environmental pollution of the silicon wafer. Pollutants are classified into four categories based on their occurrence: particles, organic matter, metal pollutants, and oxides.
Particles
Polymers, photoresists, and etching impurities make up the majority of the particles. Typically, the particles stick to the silicon surface, impacting the subsequent process' development of geometric features and electrical properties. Although the adhesion between the particles and the surface is diverse, it is primarily van der Waals attraction, thus the particle removal method is primarily to undercut the particles using physical or chemical ways, and gradually remove the particles. The particle's contact area with the silicon surface is reduced, and the particles are eventually removed.
Organics
Human skin oils, clean room air, mechanical oils, silicone vacuum greases, photoresists, cleaning solvents, and other organic contaminants can all be found in the IC process. Each contaminant affects the IC process in a different way, mainly by producing an organic layer on the wafer surface that prevents the cleaning solution from reaching the wafer surface. As a result, removing organic materials is frequently the first step in the cleaning procedure.
Metal contaminants
Metal interconnect materials are utilized to connect separate devices in the IC circuit fabrication process. Photolithography and etching are used to create contact windows on the insulating layer, and then evaporation, sputtering, or chemical vapor deposition are used to create metal interconnects (CVD). To construct interconnect lines, interconnect films such as Al-Si, Cu, and others are etched, and then the deposited dielectric layer is chemical mechanical polished (CMP). This procedure has the potential to contaminate the IC production process. Various metal contaminations are produced while constructing metal interconnects. To remove metal pollution, appropriate steps must be done.
Primary oxides and chemical oxides
In an environment including oxygen and water, silicon atoms are very easily oxidized to create an oxide layer, known as a native oxide layer. Due to the great oxidizing power of hydrogen peroxide, a chemical oxide layer will form on the silicon wafer surface after cleaning with SC-1 and SC-2 solutions. This surface oxide must be removed once the wafer has been cleaned to assure the quality of the gate oxide. Oxides produced by chemical vapor deposition (CVD) in the IC process, such as silicon nitride and silicon dioxide, should also be selectively removed in the cleaning process.