Dry snow blast cleaning for electronics and semiconductors

Snow blast technology enables dry, resource-saving cleaning for electronics and semiconductor production. It meets the highest cleanliness requirements and can be flexibly integrated into automated production lines.

Electronics and semiconductor manufacturing is facing various challenges: Increasingly smaller structure sizes, rising demands on the power density, reliability and safety of electronic components as well as new manufacturing technologies require greater precision and technical cleanliness. The increasing shortage of skilled workers is reinforcing the trend towards automating work steps, including cleaning. In addition, there are stricter requirements in terms of sustainability and resource consumption. The dry and scalable QuattroClean snow blasting technology meets these different requirements. The sustainable cleaning process requires neither water nor energy-intensive drying and can be automated as required.

From smartphones and household appliances to automobiles, medical products and aerospace - semiconductors, integrated circuits and microchips are the basis of modern applications. During their manufacture, the components undergo complex processes that are becoming ever more demanding due to increasing requirements in terms of performance, product quality and durability as well as new manufacturing technologies such as advanced packaging. And not just in terms of precision, but also in terms of the technical cleanliness that can be achieved. The benchmark here is the cleanliness defined as necessary for subsequent processes or the end application. The limit values for residual particulate contamination are often in the sub-micrometer range; for filmic-organic and inorganic contamination, they are nanolayers. The scalable QuattroClean snow blasting technology from Acp Systems AG has been proven to meet these sometimes extreme cleanliness requirements in series production in a stable and reproducible manner. And it does so for a wide variety of full-surface or partial applications such as the removal of flux residues, solder residues and tiny particles, wafer dicing, the cleaning of PCBs, masks, imagers (e.g. CCD or CMOS sensors) and exposure optics as well as before and after bonding.

In contrast to wet-chemical cleaning, which is still frequently used and requires energy-intensive drying as well as water or solvents, the process with QuattroClean technology is dry. The cleaning medium used is liquid, processed carbon dioxide recycled from chemical production processes and energy generation from biomass. It is fed through a flexibly adjustable, wear-free two-substance ring nozzle and expands into fine snow crystals as it exits. These are bundled by a separate, ring-shaped jet of compressed air and accelerated to supersonic speed. The cleaning effect is based on a combination of thermal, mechanical, solvent and sublimation effects when the easily focused jet of compressed air hits the surface to be cleaned. The crystalline carbon dioxide sublimates completely during the process, leaving the treated surfaces dry. Removed contaminants are extracted together with the process gas, preventing re-contamination of the parts and contamination of the environment.

To underpin its contribution to sustainability, the QuattroClean process in combination with process gas has been certified by Linde Green Screen. The certificate confirms that cleaning processes, especially in electronics production, do not contain any chemical substances in the cleaning medium that could harm people or the environment.

The cleaning solution is optimally adapted by Acp Systems to the respective task, company-specific requirements and production situation. To this end, the company designs existing systems on standardized modules or individually planned systems. For use in clean production facilities, the cleaning solutions, which are made entirely of stainless steel, are designed and equipped in accordance with the relevant cleanroom class. A process medium purity of 99.995% can be guaranteed for the preparation of liquid carbon dioxide and quality 1.2.1. in accordance with ISO 8573-1:2010 for the preparation of compressed air. To meet the requirements in semiconductor production, for example, a gas scrubber can also be integrated into the ultra-pure compressed air supply (XCDA) to filter out traces of organic substances.

Another advantage of the QuattroClean technology is its small footprint and flexible automation capability using robot handling or linear technology, which also ensures very short cycle times. On request, the system manufacturer can take on the customized planning, documentation and commissioning of the automation solution for the cleaning system as well as its integration into existing production lines - even for so-called flexible materials such as flexible printed circuit boards. Image processing-supported solutions enable exact automatic positioning and calibration of the parts in production lines as well as precise process monitoring and documentation.

The process design is carried out at Acp Systems in its own technical center, which has an ISO 7 class clean room with zones up to class 5 in accordance with ISO 14644-1. Under these production-related conditions, the process parameters such as volume flows for compressed air and carbon dioxide, number of blasting nozzles, blasting range and time are adapted to the respective application, the material properties, the contaminants to be removed and the required cleanliness.

The dry QuattroClean snow blasting technology is an answer to the challenges posed by various cleaning tasks in electronics production. On the one hand, the process enables the required cleanliness of electronic, mechanical, optical and sensor components to be achieved in a stable, energy- and resource-saving manner. On the other hand, the solution meets the demand for end-to-end automation of production processes (OM-3/26).