A. Laser
The main questions relating to laser are type and power. Exatron uses CO2 and Nd:YAG lasers in its systems. These lasers are described below in much more detail.

B. Galvos
Galvos are the fine motors used to turn the mirrors which deflect the laser beam to write on the target. Galvos are available from only a few companies, and come in only a few models. Galvos come in various speeds, but are generally comparable in overall performance. Exatron currently uses galvos from the General Scanning company of Boston, Mass.

C. Other Optics
Besides the mirrors on the galvos, two other optical elements are critical. The first is a Beam Expander. This is a lens device which takes a collimated incoming laser beam of perhaps 1mm diameter and turns it into a cone-shaped beam with a large base (10mm) and which is set to focus the beam on a tight spot at a set distance. This provides the smallest possible spot size on the target.

The second important optic is an f-theta lens. This lens "flattens the field" of the laser mark area. This lens accounts for the different distances from the galvos to the surface of the target as the scribe mark moves out from the center line of the target. With the lens, the beam remains focused over the entire surface area of the target.

D. Control Software
Software may be the least well understood part of the laser marking system. It is critical that the software running a laser marking system be fully functional and flexible. Exatron provides its own software for running a laser in conjunction with a handler.

An important feature of the Exatron software is the ability to put "Smart Marks" on I.C. packages. If the I.C. is tested by the Exatron system, the results of that test may generate different marks. For example, some memory chips from a single lot will run faster than others from that same lot. If the test results can differentiate the devices, each device can be marked with its speed - improving the value of the end product. Similarly, bad devices can be marked with a large "X" or other clearly identifying mark to prevent such parts from being included with good devices.

The smart mark feature is only available as a result of combining a scribing laser system with Exatron software.