Electronics production: Dry cleaning with snow blast technology

In order to remove particulate and film residues from electronic components in a scalable, inline-capable and cleanroom-compatible manner, snow jet technology is an efficient and dry cleaning process.

Whether energy, mobility or industry - electronic components and systems play a key role in the transformation towards climate neutrality. In their production, higher demands on power density and reliability as well as new solutions result in enormously increased requirements for technical cleanliness. The scalable, cleanroom-compatible and inline-capable QuattroClean snow blasting technology enables these requirements to be met in a dry, reliable and sustainable manner for a wide range of cleaning applications.

From semiconductor and microsystem production to the joining technology of printed circuit boards and assembly technology to the production of battery cells and modules, the manufacture of photovoltaics and laser-structured organic electronics, technical cleanliness has a decisive influence on the performance, functionality, reliability and service life of electronic components and systems. The benchmark here is the cleanliness defined as necessary for subsequent processes or the end application, which must be achieved in a stable and reproducible manner. In order to ensure compliance with the sometimes extreme limit values with regard to particulate, filmic-organic and inorganic residual contamination, cleaning is usually carried out in cleanrooms. The QuattroClean snow blasting technology from Acp Systems has established itself as a solution for such high-purity tasks in a design adapted to the cleanroom class.

This is a dry cleaning process for full-surface and local applications. The cleaning medium is liquid carbon dioxide recycled from chemical production processes and energy generation from biomass. It is fed through a 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 recontamination of the parts and contamination of the environment. Time-consuming and energy-intensive rinsing and drying processes are no longer necessary.

Extensive tests have shown that the QuattroClean process reproducibly meets the requirements of surface cleanliness class (ORK) 1 in accordance with VDI 2083, sheet 9.1:2006 with regard to residual particulate contamination. In addition, a particulate cleanliness corresponding to ORK 0.1 can be achieved with repeat accuracy for components that have already been wet-chemically ultra-fine cleaned. In the case of filmic residues, the cleaning results are comparable to those of other ultra-fine cleaning processes such as wet chemical and plasma cleaning as well as vacuum bake-out.

In combination with process gas from Linde, the effective QuattroClean process has the Green Screen certificate for cleaners and degreasers from Clean Production Action. The independent, non-profit organization has thus created a benchmark specifically for cleaning media used as process chemicals in manufacturing, particularly in the electronics industry. The certificate confirms that the process gas does not contain any chemical substances that are harmful to people or nature.

For optimum adaptation of the cleaning solution to the respective requirements and production situation, Acp Systems offers various systems based on standardized modules and individually planned systems. The design and equipment of the solutions, which are made entirely of stainless steel, are adapted to the respective cleanroom class. For example, a process medium purity of 99.995% can be guaranteed for liquid carbon dioxide media preparation and quality 1.2.1. in accordance with ISO 8573-1:2010 for compressed air preparation. If required, a gas scrubber can be integrated into the ultra-pure compressed air supply (XCDA) to filter out traces of organic substances. The air quality generated in this way meets the requirements of semiconductor production, for example.

One example is the compact JetCell with rotating nozzles, which will be on show at Productronica 2024. The flexible plug and play cleaning cell was developed for automated cleaning and can be easily integrated into interlinked production environments, for example directly after a stamping or injection molding system, or operated as a standalone solution. It impresses with its high cleaning performance and minimized media consumption. During surface cleaning, which can be carried out simultaneously from above and below, seamless process monitoring and control ensures that each part is treated with the previously validated process parameters. Integrated interfaces enable the digitally controllable cleaning system to be connected to a higher-level master computer.

Acp Systems has its own cleanroom technical center for process design. It enables cleaning tests to be carried out in a validated ISO 7 class cleanroom with zones up to class 5 in accordance with ISO 14644-1. The process parameters such as volume flows for compressed air and carbon dioxide, number of blasting nozzles, blasting range and time are precisely adapted to the respective application, the material properties, the contaminants to be removed and the required cleanliness. The values determined can be stored as part-specific cleaning programs in the system control.

The dry QuattroClean snow blast technology provides a cleaning solution that can be used to perform a wide range of tasks in the electronics industry reliably and efficiently. At the same time, the process enables the required cleanliness of electronic, mechanical, optical and sensor components to be achieved in an energy and resource-saving manner. (OM-2/23)