High Density Multi-Layer Circuit Applications

Metrigraphics utilizes proprietary fabrication processes to produce ultra-high density multi-layer circuits with trace widths as low as 5 microns (0.0002") and aspect ratios up to 2:1. These circuits can be fabricated on a wide variety of flexible and rigid substrate material.

Below are some application examples of the custom micro-circuits that we have fabricated.

Micro-coils are commonly used for sensing applications. The image to the right shows one end of a two conductor layer, flex circuit micro-coil with copper traces on polyimide base, via and passivation layers. We can also fabricate gold traces. There are 5 turns on this particular coil with conductor width of 18 microns ( 0.0007"). We can use photolithographic artwork to fabricate as many turns as needed. Conductor width tolerance can be held to +/- 1 micron (0.00004"). The shadow of the second layer is visible through the polyimide. Alignment of top layer to second layer can be held to +/- 1 micron. The feature in the middle is a thru-hole via (125 microns X 60 microns) making electrical connection between the top coil and the bottom coil.
The image to the right shows the traces of another coil application. This is a single layer flex circuit with multiple coils. The trace line width is 5 microns (0.0002"). We can hold line width tolerance of +/-1 micron (0.00004").
The image to the right shows a circuit with gold traces on a glass substrate. Trace line width is 25 microns (0.001"). We can hold line width tolerance of +/- 1 micron (0.00004"). Conductors can be fabricated with traces down to 5 microns (0.0002").
The two images to the right show a two layer flex circuit. The top image shows the full circuit configuration with representative pads, thru-hole vias, a small coil and fine lines/spaces. The overall circuit pattern measures 638 microns (0.0255") square. The vias are 20 microns (0.0008") square and connect to pads in the second layer. The bottom image is a close up view of the highest density area of the circuit located in the middle upper area. This image shows the uniformity of the 5 micron (0.0002") traces and spaces. Alignment of the two layers and dimensional tolerances can be held to +/- 1 micron (0.00004"). If you would like us to send you a single layer version of this sample circuit, please contact us, fill in your contact information and request the sample flex circuit.
Below is an example of a complex copper micro-coil. Each coil has an overall width of 2.3 mm (0.090") and length of 4.24 mm (0.167"). Each coil has 44 turns. There are 4 coils layered one over another and series wound for a total of 176 turns per induction system. The conductor width is 12.5 microns (0.0005"), and the spaces between conductors are also 12.5 microns. Conductor height is 7 microns (0.0003"). Each of the 4 copper conductor layers are separated by a 10 micron (0.0004") thick polyimide layer.

DRC's electroforming technology is also capable of fabricating high aspect ratio conductors. The image to the right is a scanning electron microscope (SEM) photo of a coil on a glass substrate. We can fabricate conductors on a wide variety of other substrates as well. The width of the conductors is 10 microns (0.0004"), and the height of the conductors is 25 microns (0.001"). The spaces between the conductors are also 10 microns. Dimensional tolerance is better than a micron. The resulting coil has sharp, vertical walls and flat top surfaces.