Rainbow Technology Systems is launching the ‘Rainbow Process’ at JPCA Tokyo (13–15 June). The In Contact Imaging System (ICIS) occupies only 10 m2 and has an in-built clean environment, is fully automated and does not require ovens or vacuums. Based on a liquid resist, LED’s and photo tools the process can achieve 20 micron detail and below and produce a double sided image in under 20 seconds.
Having its own controlled environment the Rainbow System can be operated without being housed in a full cleanroom. The air into the unit is controlled and the operators are separate from the process. Contact cleaning for panels entering the unit ensures ultra clean process conditions. This configuration addresses many of the issues that currently affect yields in the conventional use of wet resists.
The Rainbow process is extremely energy efficient, using on average the same power as a domestic hot water kettle for the entire process. Although the resist is liquid it does not require drying before imaging thus avoiding the need for a hot air or IR oven.
Unlike conventional wet resist, the Rainbow UV curable wet resist does not need to be pre-dried prior to imaging so energy, handling and contamination issues are all reduced.
The Rainbow System coats, images and develops in one automated process. The entire process is only 5.5m long thus saving floor space compared with conventional resist lines.
The ‘solvent free’ resist is applied at only 5 microns such that features at 20 microns and below are achieved with a conventional photo tool (silver halide). The resist is applied and imaged while wet ensuring that coverage and adhesion to the substrate is excellent. This has often been a problem associated with the use of thinner dry films. The Rainbow resist is developed in industry standard sodium or potassium carbonate solutions.
Since the Rainbow process uses the photo tool in intimate contact with the wet resist, the optical path is short when compared to dry film systems. The photo tool defines the line width obtained and 20 micron detail is standard fare for Rainbow while features as low as 5 microns have been achieved. The line definition is said to be excellent and there is no ‘stepping’ on diagonals whilst circular details are also perfect. LED’s are inherently low powered and offer a 25,000hr life with low maintenance.
The novel ICIS uses atmospheric pressure to hold photo tools against wet resist avoiding the need for expensive vacuum pumps.