We are looking at some applications that will require fine-pitch and possibly ultra fine-pitch. I am currently using a spray type batch cleaner for cleaning our stencils. Will this be adequate for fine-pitch (15 � 20 mil pitch) applications?
I�m going to reference Mr. Clouthier�s article again. It seems that the information contained within his article is answering many of the questions that are being asked. I highly recommend that everyone reads it. A copy can be found at the following web address: http://www.smartsonic.com/article.html it appears in the July '96 issue of EP&P magazine and the August '96 issue of Asian Electronics Engineer magazine. There is a series of photographs used by Mr. Clouthier to demonstrate the ineffectiveness of using sprays to clean fine-pitch. These photos do not appear on the website version. If you do not have access to back issues of either magazine, e-mail me with your snail mail address and I will send you a copy. In addition to the type of machine required, he also stresses the importance of the correct chemistry. When selecting a stencil-cleaning process, always select the chemistry first. How you apply that chemistry is secondary.
My analogy of cleaning fine-pitch with a spray type stencil cleaner is: "trying to clean fine-pitch with a spray type stencil cleaner is like trying to clean a keyhole with a fire hose." You just can't deliver the chemistry into the small apertures and the impingement of the sprays will not be effective.
In addition, Mr. Clouthier points out that high-pressure sprays will damage (bend) the delicate land mass areas between fine-pitch apertures.
I do not recommend the use of spray type systems on fine-pitch less than 20 mil.