The ACS300 Gen2 is a modular cluster system designed to meet manufacturers' needs for clean, reliable, high-throughput and modular photolithography processing for 200 and 300mm wafers. Both wafer sizes can be processed parallel or sequential without any mechanical changeover. SUSS MicroTec ACS300 Gen2 systems can be equipped with process modules for HMDS vapor priming, spin coating, spray coating, aqueous or solvent based developing, baking and cooling. It masters thin and thick resist applications as well as photosensitive polymers like polyimide, PBO and Cyclotene (BCB).
SUSS MicroTec ACS300 Gen2 addresses all requirements for sophisticated resist processing and the 3D-Integration and Wafer Level Packaging technology in particular.
Concurrent 200 and 300mm wafer processing without mechanical changeover
High-speed, high precision six-axis robot and optical centering
Excellent thick resist capabilities and best-in-class EBR performance
ACS300 Gen2 allows flexible production planning from R&D/pilot production to the volume production stage. A small footprint configuration comes with 2 load port modules directly attached to the basic frame which guarantees for optimum cost-of-ownership. With a separate EFEM the machine can be equipped with 4 load port modules. It is equipped a high-precision 6-axis robot and camera based centering. With the GYRSET feature highly uniform resist layers with thicknesses from below 1µm to over 100µm can be produced in the process bowl.
The ACS300 Gen2 can be interfaced with the MA300 Gen2 proximity mask aligner to form the integrated LithoPack300 cluster.
Spin coating is the process of evenly coating a spinning substrate with a solution. The solution, for instance a photosensitive resist, is dispensed at the center of the wafer. Subsequent acceleration as well as the rotation speed and the time allotted to the individual steps ensure that a homogeneous layer thickness remains after excess resist is spun off. Alongside the process parameters, the physical properties of the solution or photoresist determine the thickness of the applied film.
SUSS MicroTec’s proprietary GYRSET technology provides cutting-edge advantages. The GYRSET principle entails synchronous rotation of the process chamber during coating, in this way effectively reducing air turbulence over the rotating substrate. The atmosphere within the closed chamber becomes more quickly saturated with solvents, so that the resist dries more slowly and is thus distributed more evenly over the substrate. This results in significant savings in terms of required material.
Spin coating is limited in use to structures without high topography.
Features and Benefits
Spray coating involves spray application of the solution to the wafer through a nozzle. The path traveled by the nozzle over the wafer is optimized to ensure that the coating is applied evenly to the substrate. The solutions used in spray coating usually feature a very low viscosity, which guarantees that fine droplets form.
Spray coating ensures a uniform layer even with high topography substrates, making it the preferred technique for structures of this kind. Even square substrates can be easily coated using the spray technique.
Features and Benefits
Puddle developing involves dispensing a defined quantity of developer to the exposed substrate, gently spinning it to spread the developer. Due to the surface tension of the developing agent, a convex puddle is formed on the wafer. Once developing time is completed, the wafer is rotated quickly to spin off the developer agent. The wafer is subsequently rinsed with deionized water and dried, once again at a high rotation speed. The main advantage of the technique is that only very little developing agent is required while maintaining excellent process results.
Puddle developing is no longer feasible when the developing agent becomes saturated, for example when a large quantity of photoresist needs to be removed or a high structural topography prevents exchange of the developer. In such cases, a multi-stage puddle developing process or spray developing is used.
Features and Benefits
Spray developing involves low-speed rotation of the substrate as it is developed. The exposed areas are continuously nozzle-sprayed with fresh developing agent to prevent the developer from becoming saturated. This technique offers advantages over puddle developing in processes involving thick photoresists and large surfaces to be developed. At the end of the process, the substrate is rinsed with deionized water and then spun dried.
Features and Benefits
SUSS MicroTec's proprietary AltaSpray® coating technology is a unique resist deposition method that is capable of producing highly uniform resist films on different 3-D microstructures. The AltaSpray® technology is capable of coating 90° corners, KOH etched cavities, Through Silicon Vias (TSVs) or lenses with topographies ranging from a few micron to 600µm or more. The ability to produce conformal resist coatings on severe topography makes them the ideal choice for R&D, MEMS, 3D-Integration and Wafer Level Packaging applications like 3D image sensor packaging.
SUSS AltaSpray® topography coating modules are available for the ACS200 Gen3 and ACS300 Gen2 platforms. The AltaSpray module allows processing of wafers with diameters of 200mm and 300mm as well as squares up to 8" edge length. All AltaSpray coater modules are can be equipped with up to two separate spray dispense systems. The sophisticated resist supply system offers unmatched process stability and reproducibility. All spray and cleaning parameters can be programmed in the recipe.
SUSS MicroTec's baking equipment provide excellent uniformity and offer optional functionalities such as proximity baking and nitrogen purge. Substrates that can be processed range from small pieces to 300 mm wafers.
SUSS MicroTec’s proprietary GYRSET® technology helps to significantly improve spin coating process results by improving the conditions during coating. With the help of a rotating cover a turbulence-free atmosphere, highly saturated with solvents, can be created. This not only makes the outcome more independent from the ambient temperature and humidity. It also substantially reduces the amount of material required to coat a wafer therefore being beneficial for environmental sustainability.
The GYRSET® technology is highly suitable for processing thick resists.
Vapor priming prepares the wafer surface to improve the surface condition for optimal resist adhesion. The SUSS vapor prime process is executed automatically and fulfills all safety requirements.
Bent and warped wafers are carefully pulled flat before alignment and exposure. Due to the variety of the parameters that affect it, an optimal tooling implementation requires adaptation for the specific substrate.