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Chip embedding in printed circuit board production

: Ostmann, A.; Kriechbaum, A.; Baets, J. de; Kostner, H.

International Microelectronics and Packaging Society -IMAPS-, Nordic Chapter:
IMAPS Nordic Annual Conference 2005 : Microelectronics packaging - the key to the future; Tønsberg, 11-14 Sept. 2005; proceedings
Tønsberg, 2005
ISBN: 951-98002-7-1
International Microelectronics and Packaging Society (IMAPS Nordic Annual Conference) <2005, Tønsberg>
Fraunhofer IZM ()

In this paper the development of a production-capable technology for embedding active components into printed circuit boards (PCBs) will be presented. The work is jointly performed by a consortium of partners from industry and research within the frame of the European research project "HIDING DIES". The basic concept is to embed ultra-thin semiconductor chips into the laminated build-up layers of microvia PCBs. Wafers are first thinned down to 50 µm or even less. In order to achieve a surface which is compatible to a PCB metallization process, the Al contact pads are covered by Cu bumps. The next step is to die bond the chips using printed adhesive or die attach film. Precise thickness control of the bond line is essential for maintaining uniform thicknesses of the build-up dielectric on top of the chip. RCC (resin coated copper) layers with thin Cu are used for vacuum lamination. Process parameters had to be tuned in order to avoid damage to the chips during lamination. Contacts to the chip are made by laser drilled microvias followed by a PCB-compatible Cu plating. All the process steps in this technology are set up for large scale manufacturing, using large panel sizes (18" x 24") in a combination with high accuracy positioning methods using local fiducials for die placement, laser drilling and laser direct imaging. The paper focuses on technological issues and solutions to achieve the described die embedding. Results of reliability measurements as well as electrical measurements will be presented.