Back-end of Line
Fraunhofer Institute for Electronic Nano Systems
Dielectric Chemical Vapour Deposition (CVD)
The chemical vapour deposition (CVD) is one of the basic techniques for thin film deposition in the field of BEOL processing. The Department Back-End of Line in collaboration with the Center for Microtechnologies has a long time expert knowledge in CVD of various dielectric films.
CVD deposition techniques and dielectric materials
Thermal Low-pressure CVD (LPCVD), ≤ 800 °C:
- SiOx (TEOS)
Plasma Enhanced CVD (PECVD), ≤ 450 °C:
- SiOx (TEOS, SiH4)
- SiCOH (low-k dielectric, BlackDiamondTM)
Application of the dielectric films
- Inter- and Intra-Metal Dielectrics (IMD) in interconnect systems
- Diffusion barriers
- Stop and hard mask films during patterning
- Capping films (e.g. pore sealing)
- Sacrificial films
- Stressor films for enhancement of MOS transistor channel carrier mobility
Research and development topics
In connection with the listed fields of application distinct properties of the dielectric films are optimized. On the one hand the previous and current activities of the department BEOL aim on the following basic characteristics:
- electrical properties (k-value, leakage current, field breakdown strength),
- mechanical properties (Young’s modulus, Hardness, yield stress, intrinsic stress, adhesion strength),
- thermal properties (thermal conductivity, thermal stability).
On the other hand process compatibility as well as BEOL integration issues of dielectric films are in the focus of our groups work.
The BEOL group of the Fraunhofer ENAS Chemnitz applies commercial CVD tools. The deposition of LPCVD films is performed by a LP-Thermtech tool with a maximum wafer size of 6 inch. In addition, two Applied Materials P5000TM are available for the deposition of PECVD thin films on wafers with a maximum diameter of 8 inches. Moreover, in-situ plasma treatments of dielectric films are feasible.
The following innovations were realized recently
- In-situ UV-treatment of dielectric films in a chamber of an Applied Materials P5000TM tool
- Liquid injection system for screening of advanced precursors for PECVD dielectric films, e.g. of novel highly stressed materials