Recent trends to miniaturized systems such as smartphones and wearables, as well as the rise of autonomous vehicles relying on all-electric and smart in-car systems, have brought unprecedented needs for superior performance, functionality, and cost requirements. Transistor scaling alone cannot meet these metrics unless the remaining system components such as substrates and interconnections are scaled down to bridge the gap between transistor and system scaling. In this regard, 3D glass system packages have emerged as a promising alternative due to their ultra-short system interconnection lengths, higher component densities and system reliability enabled by the tailorable coefficient of thermal expansion (CTE), high dimensional stability and surface smoothness, outstanding electrical properties and low-cost panel-level processability of glass. The research objectives are to demonstrate board-level reliability of large, thin, glass packages directly mounted on PCB with conventional BGAs at pitches of 400µm SMT and smaller. Two key innovations are introduced to accomplish the objectives: a.) Reworkable circumferential polymer collars providing strain-relief at critical high stress concentration areas in the solder joints, b.) novel Mn-doped SACMTM solder to provide superior drop test performance without degrading thermomechanical reliability. Modeling, package and board design, fabrication and reliability characterization were carried out to demonstrate reliable board-level interconnections of large, ultra-thin glass packages. Finite-element modeling (FEM) was used to investigate the effectiveness of circumferential polymer collars as a strain-relief solution on fatigue performance. Experimental results with polymer collars indicated a 2X improvement in drop performance and 30% improvement in fatigue life. Failure analysis was performed using characterization techniques such as confocal surface acoustic microscopy (C-SAM), optical microscopy, X-ray imaging, and scanning electron microscopy/energy dispersive spectrometry (SEM/EDS). Model-to-experiment correlation was performed to validate the effectiveness of polymer collars as a strain-relief mechanism. Enhancement in board-level reliability performance with advances in solder materials based on Mn-doped SACMTM is demonstrated in the last part of the thesis.The studies, thus, demonstrate material, design and process innovations for package-to-board interconnection reliability with ultra-thin, large glass packages.

Abstract The target of this dissertation is to propose a new qualification tool (QT) for component package (CP) feasibility qualification in telecommunication infrastructure products. The primary reason for the introduction of the QT is the Electrical and Electronic Equipment (EEE) manufacturers’ continuing development of new products with tighter product requirements, e.g. compact size, environmental friendliness and cost-efficiency. CP’s need to match these requirements and thus they need to be developed further and qualified/re-qualified continuously. This qualification process with the new component package needs to be done in as early phase as possible, enabling EEE manufacturers to implement component packages into use with minimal risk. Qualification of a CP to match with these requirements is usually done with the qualification expert’s possessed know-how. However, this process takes a lot of time as all the possible data must be collected or even created. Thus a new method needs to be introduced for early phase qualification. The QT proposed here contains eight qualification sub-areas for feasibility qualification of the CP and it uses three qualification principles. Including all these sub-areas to the feasibility qualification clearly enables more reliable and trustworthy conclusions. The QT is required as an assisting qualification tool for specialists and as a preliminary qualification tool, e.g. for hardware (HW) designers or component engineers. It could be used also as a requirement communication tool between customers and component package manufacturers. After the QT’s sub-areas and functionality were developed, functionality and approval limits were set-up with 44 different widely used commercial CPs. This historical data is recorded for future use in its own database. The QT is a unique tool as there are no competing open-source tools available in the market that can be tailored to match with the user’s own requirements. / Tiivistelmä Työn tarkoituksena oli esittää uusi kvalifiointityökalu (QT) infrastruktuurituotteiden komponenttikoteloiden käytettävyyden arviointiin. Laitevalmistajien kehittäessä uusia pienempiä, ympäristöystävällisempiä ja kustannustehokkaampia laitteita asettavat he samalla vastaavia vaatimuksia myös komponenttikoteloille. Vastaavasti komponenttien valmistajat joutuvat kehittämään komponentteja ottamalla käyttöön uusia materiaaleja ja kotelorakenteita ja kvalifioimaan niiden ominaisuuksia asiakkaiden vaatimuksien mukaisesti. Laitevalmistajien riski uusien komponenttikoteloiden käyttöönotossa pystytään minimoimaan, kun komponenttikoteloiden kvalifiointi tehdään mahdollisimman aikaisessa vaiheessa. Kvalifioinnit tehdään yleensä kvalifiointiasiantuntijoiden tietotaidon perusteella. Tämä prosessi on kuitenkin perinteisesti hidas, joten nopeammalle arviointimenetelmälle on selkeä tarve. Työssä kehitettyyn kvalifiointityökaluun määritettiin kahdeksan arviointialuetta. Lisäksi sitä voidaan käyttää kolmella eri kvalifiontiperiaatteella. Näiden arviointialueiden huomioiminen kvalifiointiprosessin aikana parantaa selkeästi tuloksen luotettavuutta ja todenmukaisuutta. Työkalu on määritetty siten, että sitä voivat käyttää asiantuntijat avustavana kvalifiointityökaluna sekä suunnittelijat / komponentti-insinöörit alustavana kvalifiointityökaluna. Lisäksi sitä voidaan myös käyttää asiakasvaatimusten määrityksessä ja tiedonvälityksessä asiakkaan ja toimittajan välillä. QT:n kvalifiointialueiden määrittelyn ja toiminnallisuuden rakentamisen jälkeen, hyväksyntäkriteerit tutkittiin ja arvioitiin käyttäen 44 erilaista kaupallista komponenttikoteloa työkalun lopullisen hienosäädön tekemiseksi. Koska kvalifioinnin tiedot tallennetaan QT:n tietokantaan, pystyy laitevalmistajat hyödyntämään aikaisemmat historiatiedot tulevissa kvalifioinneissa. QT on ennen näkemätön työkalu, sillä markkinoilla ei ole vastaavia avoimen lähdekoodin kvalifiointityökaluja tarjolla, jota voidaan räätälöidä asiakkaan omien tarpeiden mukaisesti.