No abstract

Small modules on the basis of laminate substrates are oflen used as a functional subunit in electronic applications. Currently most of them are made by chip and wire technique as one kind of bare chip assembly to fu@U the requirements of size reduction.Low costflip-chip technology is one of the most promising approaches forfunher cost and size reduction. In this paper a special car radio submodule is chosen for exemplification. We compare a SMD compatible FC soldering process using eutectic solder bumps and underfiIling with an anisotropically conductive adhesive (ACA) FC bonding process using tape or paste materials. FC soldering: For FC soldering an electroless, maskless NiLAu plating for Under Bump Metallization (UBM) was chosen. The solder deposition itself is done by stencil printing whereas other cost efficient deposition techniques in the markt have been observed. The FC assembly is integrated into a standard SMD line. Different unde@ll methods for quick undefilling are shown and failure mechanisms and lifetime predictions of assembledflip chips are demonstrated.ACA-FC bondinc For this process electroless NUAu bumping is used as well. An assembly process for ACAs using a semiautomatic FC bonder is developed. In order to reduce the time for mounting the ACA has been precured. The aspects of diferent process flows including ACA deposition techniques, tape and paste adhesives and filler materials are discussed. The influence of high current, climate, and thermal cycling on the contact resistance and the lowj-equency noise spectrum is shown. In summarizing this work we describe the benefits and disadvantages of both techniques and discuss the potential forfirther developments and applications.&7803452(F7/98 S10.00 01998 IEEE

Abstruct-We developed a new type of laminate-based multichip module, the interface of which to the next higher system level is a ball grid array. The modules contain both integrated circuits and passive components like chip capacitors and resistors. The protection of the IC's is done by a plastic cap which is glued to the substrate. We consider conceptional questions, the construction of the modules, and the actual status of qualification.Zndex Terms-Multichip modules, ball grid array, automotive electronics, chip-on-board.

In the manufacture of resistors with low TCR values it is found that difficulties start at TCR values of less than ±50 ppm/°C. This paper will show if ±50 ppm/°C is a realistic value for high volume production.