The European CSP perspective

M. Töpper, A. Schubert, H. Reichl; Fraunhofer-Institute for Reliability and Microintegration, Technical University, Berlin

Packaging roadmaps are caught between IC roadmaps and the trends in PCB assembly industry. During the last decade, most of the through-hole (THT) mounting packages (DIP, DIL, PGA, etc.) were replaced by surface mount devices, SMDs such as TSOP, PQFP, etc. The ongoing progress in IC technology increases density, speed, power and I/O count. For example, gate density on a chip for highend applications is increasing by about 75% per year, resulting in a growth of I/Os by 40% per year. Along with the roadmaps published by national organizations such as the Semiconductor Industry Association (SIA) in the United States, and the Electronic Industries Association of Japan (EIAJ), many IC manufacturers have their own roadmaps, describing the evolution of the physical parameters of ICs and of electronic packaging. Several reasons could lead to significant changes in such roadmaps, for example, the upcoming of completely different IC technologies, adaption of other packages or advanced products changing the electronic marketplace.

For the European electronic industry, three main areas of applications are dominant: telecommunications, automotive, and mobile systems of all kinds. For automotive applications, the increase in the IC consumption will be around 15% per year. So, very interesting is a look at the further developments which are expected in Europe according to the Netpack (network in microel-ectronic system integrationtechnology packaging) research project.

The perspective presented here is based on the response of European semiconductor manufacturers, assembly and packaging houses and system manufacturers asked to predict their area-array packaging activities until the year 2004. It is important to note that the data do not present a consensus as to what must happen in assembly and packaging to address specific IC roadmaps. These data reflect the actual business and plans of corporations addressing the automotive, telecommunication and mobile system markets. Inconsistencies arise because the companies have estimated independently where each parameter will be going forward in time. A roadmap provides not the absolute truth but the best way to manage the communication among the participants in industry.

The trends presented here are a bottom-up roadmap that places considerable emphasis on the package-to-board interface. The requirements for CSP in these applications are more driven by the specific needs of the products than by the technology of silicon processing. In the top-down approach (chip-to-package interface) as performed by SIA and EIAJ, there are changes anticipated in IC technology which guide the predictions for packaging requirements. The packaging technology trend worldwide has been going from peripheral contact through array contact to chip-size packages and flip chip.

The increased IC complexity (high I/O count, larg die, high speed, signal integrity and high power dissipation), and the overall system miniaturization is pushing the CSP technologies. Against the predicted trend for dramatically increased I/O counts is the move towards higher levels of integration, both in single-chip designs and through the use of multi-chip modules. The adaption of the CSP technolgy for the three European main markets is different. For mobile systems and telecommunication, CSP is, at present, in the phase of prototyping/manufacture. The production status is achieved in 1999 for the mobile systems and in the year 2000 for telecommunications. For automotive applications it will take more time: switching from prototyping into full production is predicted for the year 2002.

Of the three markets, telecommunications is the most performance-driven. The types of products are portable phones (GSM, DECT), pagers, ATM switching equipment, long-range optical transmission (10Gbits/s), microwave transmission devices, and multimedia communications (sound, video, data). Especially this applicationarea now faces performance limitations by packaging issues. The ICs are requiring more I/Os, consequently causing a finer pitch, operating at higher frequencies and dissipating more power than either the automotive or mobile systems applications.

Mobile systems put a premium on reducing size and weight but are also very sensitive to performance and cost issues. The perspective for CSP strongly reflects these factors showing the trend to reduce size and weight in all packaging and IC technology aspects.

By the year 2000, boards for mobile electronics will be at a mix of BT, flex and build-up technologies, while the extensive use of flex is unique for these products.

There is a constantly continuing increase in the use of microelectronics in automotive applications. A lot of entirely mechanical functions have been shifted to electronically controlled systems; moreover, electronics offer an additional potential for new functions. Typically, these applications show special requirements, such as immunity to radiation and emission, low cost and high reliability, increased circuit density, large board size and smaller packages, high functionality, and sensors for exhaust gas, fluid control and wear. The technology associated with these necessities demands increased flexibility and lower costs while improving reliability at higher operating temperatures. In general, the automotive market shows the least agressive changes of the three application areas for packaging and assembly. Because of the somewhat opposing needs for both high reliability and low cost, automotive electronics has been slow to adopt new technologies. The strategy could be de-scbribed as waiting until the costs of advanced packages and assembly technologies with high reliability is decreassing.

The CSP in a single-chip package is able to fulfill most of the requirements of the discussed electronic markets. Full compatibility to SMT manufacture is given, therefore no additional processes or extra equipment is necessary for the assembly of CSPs. It is assumed that CSP will be an upcoming standard package which can be tested as other standard devices. All future CSP solutions have to conform to the CTE mismatch between IC and board. A large variety of CSP concepts already exists. First low-cost approaches use flip-chip techniques on top of interposers from organic material (FR-4, polymer tapes) including the underfill process. In the future, the CSP will be made by a technology which is performed fully on the wafer. These processes are called wafer-level packaging or fab-integrated packaging. It will play an important role for the completion of upcoming packaging requirements, because wafer level or fab integration will provide a highly economical solution for the characterization of the next wafer fab generations.

Netpack, the European network in microelectronic system integration technology packaging, was established to help the industry to meet the challenges of the world market. Co-operation between the semiconductor companies and system manufacturers has to be stimulated. Fraunhofer IZM is organizing Netpack which is sponsored by the EU.

Engine – Transmission control, digitalengine control, lamda control, engine power control

Communications – Car phone, navigation, on-board computer, radio, control by speech

Convencience features – Heating, air conditioning control, power seats with memory, central locking systems

Safety – Radar distance warning system, wash/wipe control, monitoring systems for fluid levels and component wear, anti-lock bracking system, traction control,vehicle dynamics control

Im Netpack-Projekt wurde die bis zum Jahr 2004 absehbare Entwicklung bei CSPs (Chip-Scale-Packages) in den drei wichtigen europäischen Applikationsbereichen Telekommunikation, Fahrzeugelektronik und mobile Systeme untersucht. Der Single-Chip-CSP erfüllt praktisch alle Anforderungen. Die künftige Integration auf Wafer-Level ist absehbar.

L’évolution prévue d’ici 2004 our les CSP (Chip-Scale-Packages) dans les trois applications importantes que sont la télécommunication, l’électronique appliquée aux véhicules et les systèmes mobiles, a été étudiée dans le cadre du projet Netpack. Le Single-Chip-CSP remplit pratiquement tous les critères. L’intégration future au niveau de la tranche de silicium est prévisible.

Nel progetto Netpack è stato analizzato lo sviluppo prevedibile sino all’anno 2004 riguardo ai CSP (chip-Scale-Packages) per i tre importanti campi europei di applicazione telecomunicazione, elettronica di bordo per autoveicoli e sistemi mobili. Il Single-Chip-CSP soddisfa praticamente tutti i requisiti. È prevedibile la prossima integrazione su livello wafer.

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