Advanced Ceramics for
High-Tech Industries

Processes & Skills : Laser structuring of interconnection circuits on ceramic carriers

Laser ablation technology helps the engineer to develop circuit carriers which cannot be manufactured with chemical etching technology. This kind of product results from combining the technologies of precision-grinding of ceramics and laser ablation of metallised thin-film layers. We name this concept "three-dimensional interconnection circuit or CI3D".

Principle

The laser structuring consist to etch directly a metallization layer deposited on a ceramic carrier with a laser beam without using a mask. This is called laser micromachining or laser ablation - because metal is ablated.

Laser ablation allows patterns to be etched directly on the ceramics substrate, very rapidly and beam displacements to be programmed limitless.

Equipment

Solid-state lasers are mostly used for micromachining applications because they feature precision, speed and selective etching. We currently use a Nd :YAG laser with 60 W output. It enables us to etch thin-film metallised layers with thickness of up to 5 µm without any problem. When thicker layers are required, additional electroplating is necessary after etching.

Making very small features with this kind of laser is possible - straight tracks that are 100 µm-wide with insulation spacing as small as 100 µm. Lateral resolution is a few microns.

Machining process

Although the laser ablation allows to structure flat substrates, this is specially a technology to achieve uninterrupted paths over several planes of a three-dimensional carrier. For instance, it allows to reach two metallised areas located on different heights by changing the focal plane or achieve a continuous track around a cylinder.

The only required tooling is a jig for holding the part. As a consequence, costs and lead times for setting-up and masks are reduced and thus making the process of interest for fast prototyping.

Benefits

This technology offers the following advantages :

the ceramic carrier exhibits dimensional stability as well as high electrical insulation
the etching of distinct and complex interconnection patterns on each of the faces represents programming time only but no additional mask costs
microelectronics components can be positionned in relation to each other in space
the process is suited for prototyping as well as for the manufacturing of components in production quantities of up to a few thousands per month
a wide range of designs can be achieved.

A « circuit carrier » is therefore made available to the final user who can bond onto his microelectronics components – sensor, calculator, chip, LED…- according to his own interconnection pattern. The demand for such products results from either the need to have mechanical and electrical functions together on a same carrier.

Press release

Laser etching of ICs on ceramic carrier