LDS Design Rules

Download the complete LDS Design Rules Here: Design Rules

The following is a brief summary of design considerations for producing LDS 3D-MID.

Designing three-dimensional circuitry bodies (MIDs)

Lines and Spaces

One of the important goals during the development and manufacture of 3-dimensional circuitry is the efficient use of space with the finest possible structures.

Track widths of >150 µm (6mil) and gaps of >200 µm (8mil) are possible with 10 – 12 mil optimal.

Size of work-piece

The processing zone of the component on the laser platen has a base diameter of 160 mm (~6 inches), a height of 24 mm (~1 inch) and a lateral area angle of inclination to the base of 77°

Angle of Attack

The surface of the polymer is activated by the laser light. The laser beam’s maximum angle of incidence to the surface to be structured is 70°.

The angle of incidence is the angle between the orthogonal to the activated surface and the laser beam. Angles of incidence exceeding 70° are reduced by rotating the component during the laser processing step. This technique is also used to structure artwork on surfaces separated by angles of 90°.

Walls and Ejection Pins

Zones to be activated should not directly touch walls. The separation for walls with an angle of 45° should be >150 µm and the separation from steeper walls with angles of 70°, for instance, should be >250 µm. Ejector pins should be placed to avoid the activation areas.

Optimum cycle times

The cycle time of each component is mainly determined by the handling time and the structuring time, which is also proportional to the layout area. The handling time is mainly determined by the number of positions the component has to be placed to obtain laser coverage. The number of positions and the layout area should be reduced to a minimum by appropriate component design.

Activating through-holes

Vias have to be conical on one or both sides depending on the thickness of the material to ensure the laser can process the inside walls of through-plated holes at a suitable angle of incidence.

In the case of thick walls, the internal diameters of the vias must be enlarged to ensure unimpeded processing by the laser beam using aspect ratios for simple cones of 1:1 and 2:1 for double cones.

Fixtures, clamps and bonding seams

The components are held in a fixture during laser structuring and assembly. The fixing positions must not harm any sensitive parts such as tracks, contact pads or component seats. Tracks must not be laid over bonding seams of the thermoplastic part.