The capacity to deposit different materials is clearly one of the qualifying aspects of an advanced front-end structure. In our case we use four different pieces of equipment for dielectric materials and one for metals.

Dielectric Materials

Specifically for dielectric materials we have:

STS MAC system designed to deposit dielectric material with high accuracy refractive index and elevate absorption coefficient control. It is configured with 2 different plasma sources at different frequencies (380 KHz and 13.56 MHz) , dedicated to control both stress and deposition rate. The control of RI is achieved by doping the layer with controlled GeH4 flow or a proper mixture gas reactions between gas species SiH4 /NH3 /N2O in a process reactor at 350°C in a MTorr pressure range. A special gas distribution system is designed for high uniformity across the wafer and low particle generation. The system is equipped with an automatic loading robot and vacuum transfer chamber for high throughput.

 

OXFORD PLUS PRO 100 is designed to deposit dielectric materials with planarization and conformal coating. It uses a PECVD plasma system under vacuum at controlled temperature by liquid precursors (TMB TMP and TEOS). The plasma is generated with 2 different power sources at 13.56 MHz and 90-450KHz for tuning the material properties.

The deposited layer is processed to have low flow temperature in order to achieve high conformal properties on topography with high aspect ratio.

 

SEMCO system and VTR 7000 system are designed for the deposition of dielectric materiala with stoichiometric compositions such as Si3N4 and Polysilicon using Low Pressure Chemical Vapour Deposition (LPCVD).

The Semco system is also equipped for annealing and oxidation. Such processes are in fact complementary steps for material consolidation after Plasma Deposition and are also used to grow stoichiometric oxide layers on Silicon surfaces. The Semco system uses 2 horizontal SiC tubes in the temperature range of 750°C up to 1150°C. The “device layers” are located in a flat temperature area where the T is controlled in the range of +/- 1°C throughout the full processing range.

PECVD

Metals

The deposition of metal films is necessary to implement the following features on the devices: adhesion layers, barrier layers, electrical contacts, resistors and alloys. Such technology prepares the device for the following packaging interconnection and soldering. The equipment dedicated to this purpose is the:

TEMESCAL BCD2800 evaporation system, configured with six crucibles, one process chamber and a Cryo pump system. It is also equipped with six “crystal control systems” and the total process length is 1m in order to optimize the depositions by “Lift-off “ technique.

The configuration of the tool can guarantee any sequence deposition for high thickness as well as an accurate control of stoichiometric alloys (for example Au/Sn 80/20 weight %).