Marking Individual Integrated Circuits (IC) Dies

Recently, an electronics circuit manufacturer called the Helpline concerning a problem they were having marking individual IC dies.An electronics circuit manufacturer recently called the Helpline concerning a problem they were having marking individual IC dies. The dies were being ink dot marked by hand, in order to be identified by optical recognition systems downstream in the printed circuit board assembly process. An example of this type of fiducial marking is shown in Figure 2-1.

They desired to coat the final circuit board with a commercial protective coating called Parylene™. This material is deposited via a chemical vapor deposition process, yielding a pin-hole free thin film, with a robust dielectric breakdown strength. In preparation for the deposition process, the printed circuit boards are required to be cleaned with hot isopropyl alcohol in order to guarantee adequate adhesion of the Parylene™. Unfortunately, the cleaning process was removing the ink dots used to identify the integrated circuit dies. The manufacturer tried many potential marking materials including cosmetic nail polish. The results were mixed at best.

After much trial and error, they decided to place a call to the EMPF Helpline to ask for assistance in addressing the problem. The staff of the EMPF proposed a commercially available epoxy-based ink and application process to indelibly mark each die. This recommendation turned out to be the solution to their die marking issue.

The EMPF can perform ink marking permanency tests, as well as an extensive array of accelerated aging and chemical resistance tests to evaluate electronic assemblies. In addition, the EMPF routinely designs and characterizes assembly processes for use on manufacturing lines.