Aluminum nitride substrate

A semi-rigid or flexible double-sided multi-layer printed circuit board that is sequentially laminated and suitable for wire bonding and surface mount assembly, the printed circuit board comprising:

• an aluminum nitride (AIN) substrate that includes:
• a layer of cladding copper;
• an AIN thin film disposed on top of the layer of cladding copper;
• and
• a layer of high-frequency polymer disposed on top of the AIN thin film, wherein:
• the AIN substrate forms a first layer of the printed circuit board;
• and
• the AIN substrate comprises a heat spreader that laterally spreads out heat from a heat sink on the printed circuit board to form a thermal dissipation path parallel with a signal path on the printed circuit board;
• and
• a main substrate aligned to and bonded with the AIN substrate, the main substrate including one or more additional layers of the printed circuit board.

An optical waveguide comprising:

• a layer of high-frequency polymer;
• a first aluminum nitride (AIN) thin film disposed on top of the layer of high-frequency polymer, the first AIN thin film including nitrogen content with a first nitrogen concentration level and a first index of refraction;
• and
• a second AIN thin film embedded in the first AIN thin film, the second AIN thin film including nitrogen content with a second nitrogen concentration level and a second index of refraction, wherein:
• the first nitrogen concentration level is lower than the second nitrogen concentration level;
• the first index of refraction is lower than the second index of refraction;
• and
• the second AIN thin film is embedded in the first AIN thin film to guide a light beam to propagate through the second AIN thin film.