glassPack: a novel photonic packaging and integration technology using thin glass foils

Abstract

glassPack" will be introduced as a novel photonic packaging concept for a wide area of applications like high-speed electronic systems and sensors. The usage of thin glass foils with a thickness of some tens of microns as substrate and interconnection material will be discussed. Photonic packaging in such hybrid optoelectronic systems involves single packages, modules, and subsystems comprising at least one optoelectronic device, micro-optical element or optical interconnection. Thin glass is a commercially available and reliable material with high thermal resistance and excellent optical properties. Because glass is a well known material, many technologies like polishing, plating, etching and refractive index tuning are already known. In combination with newly developed integration technologies, a complete glass based package on wafer level can be realized. The main ideas of the "glassPack" concept are: selection of suitable glass foils as substrate material, realization of microsystem compatible structuring technologies like cutting, drilling and etching, integration of optical waveguides by ion-exchange for single-and multi-mode applications, implementation of optical interconnects between fibres and integrated waveguides by laser fusion, integration of electrical wires and feed throughs, assembly of electronic and optoelectronic components, and bonding of the thin glass foils to 3D-stacks. Furthermore, the integration of micro fluidic channels into a "glassPack" will be supported. A sensor module containing optical waveguides, fluidic channels, electrical wires and components like a laser, two photodiodes and two flip-chips will be presented to demonstrate the suitability of glass as a material for integrated microsystems.

Copper Plating on Glass Using a Solution Processed Copper-Titanium Oxide Catalytic Adhesion Layer

“…[1][2][3] Two examples are in 2.5 D/3 D electronic device and RF module packaging. [4][5][6][7] In addition to these properties, abundance and availability in a wide range of shape and size make glass an attractive economic substitute for silicon in interposers.…”

Evaluation of graded index glass waveguides for board-level WDM optical chip-to-chip communications

“…Down-draw technology is used for glass manufacturing resulting in very thin, large formats and excellent smooth surface properties. Combining a suitable thin glass like that with the ionexchange technology [4] results in high-performing planar waveguides that are highly compatible with standard packaging processes on board and wafer level [5]. The optical properties of thin glass are similar to those of glass optical fibers used in telecommunication networks operating at wavelengths of 1310 nm and 1550 nm.…”

glassPack — A 3D glass based interposer concept for SiP with integrated optical interconnects

“…The surfaces have to be activated before the thin glass sheets are brought in contact and remain joined as result of a very complex phenomenon which involves chemical bonding, static electrical charges, Van-der-Waals forces etc. [8]. For our first complex e/o transceiver we have used adhesive bonding to stack the optical waveguide layer with mirror surfaces directly beneath the electrical HermeS layer [6].…”

“…As a result for 200 µm thick vias, uniform metal deposition inside the hole is possible during the plating process. Instead of gold, electro-plating of copper in various thicknesses from 10 to 100 µm in combination with a nickel barrier and finally deposited 100 nm flash gold provides a suitable metallization for soldering and wire bonding [8].…”