This master thesis describes the design of increasing the efficiency of production lines with solder robots. In beginning of this work is a description of product and current process. There are also variants of design solutions for soldering palettes and the best on is chosen. The last part of this work includes design automation soldering process.

This thesis presents a research into the solder interconnects made through the reactive bonding process based on the self-propagating reaction. A numerical study of soldering conditions in the heat affected zone (HAZ) during bonding was initially carried out in order to understand the self-propagating reactive bonding and the related influencing factors. This was subsequently followed by an extensive experimental work to evaluate the feasibility and reliability of the reactive bonding process to enable the optimisation of processing parameters, which had provided a detailed understanding in terms of interfacial characteristics and bonding strengths. In addition, by focusing on the microstructure of the bonds resulted from the self-propagating reactions, the interfacial reactions and microstructural evolution of the bonded structures and effects of high-temperature aging were studied in details and discussed accordingly. To study the soldering conditions, a 3D time-dependent model is established to describe the temperature and stress field induced during self-propagating reactions. The transient temperature and stress distribution at the critical locations are identified. This thus allows the prediction of the melting status of solder alloys and the stress concentration points (weak points) in the bond under certain soldering conditions, e.g. ambient temperature, pressure, dimension and type of solder materials. Experimentally, the characterisation of interconnects bonded using various materials under different technical conditions is carried out. This ultimately assists the understanding of the feasibility, reliability and failure modes of reactive bonding technique, as well as the criteria and optimisation to form robust joints. The formation of phases such as intermetallic compounds (IMCs) and mechanism of interfacial reactions during reactive bonding and subsequent aging are elaborated. The composition, dimension, distribution of phases have been examined through cross-sectional observations. The underlying temperature and stress profile determining the diffusion, crystallization and growth of phases are defined by numerical predictions. XXI Through the comparative analysis of the experimental and numerical results, the unique phases developed in the self-propagating joints are attributed to the solid-liquid-convective diffusion, directional solidification and non-equilibrium crystallization. The recrystallization and growth of phases during aging are revealed to be resulted from the solid-state diffusion and equilibration induced by the high-temperature heating. In conclusion, the interfacial reactions and microstructural evolution of interconnect developed through self-propagating reactive bonding are studied and correlated with the related influencing factors that has been obtained from these predictions and experiments. The results and findings enable the extensive uses of self-propagating reactive bonding technology for new design and assembly capable of various applications in electronic packaging. It also greatly contributes to the fundamentals of the crystallization and soldering mechanism of materials under the non-equilibrium conditions.

Au cours des dernières années, la demande de plus en plus forte pour des mémoires non-volatiles performantes, a mené au développement des technologies NOR Flash et NAND Flash, qui dominent aujourd'hui le marché des mémoires non-volatiles. Cependant, la miniaturisation de ces technologies, qui permettait d'en réduire le coût, laisse aujourd'hui entrevoir ses limites. En conséquence, des mémoires alternatives et émergentes sont développées, et parmi celles-ci, la technologie des mémoires à changement de phase, ou PCRAM, est l'une des candidates les plus prometteuses tant pour remplacer les mémoires Flash, notamment de type NOR, que pour accéder à de nouveaux marchés tels que le marché des SCM. Toutefois, afin d'être pleinement compétitives avec les autres technologies mémoires, certaines performances de la technologie PCRAM doivent encore être améliorées. Au cours de cette thèse, nous cherchons donc à obtenir des dispositifs PCRAM plus performants. Parmi les résultats présentés, nous réduisons les courants de programmation et la consommation électrique des dispositifs tout en augmentant la rétention de l'information à haute température. Pour cela, nous modifions la structure du dispositif ou nous utilisons un matériau à changement de phase alternatif. De plus, à l'aide de solutions innovantes, nous permettons aux dispositifs PCRAM de conserver l'information pendant une éventuelle étape de soudure de la puce mémoire. Enfin, nous avons conçu, développé et validé un procédé de fabrication permettant d'intégrer une diode PN de sélection en Silicium en série avec un élément résistif PCRAM, démontrant l'intérêt de ce sélecteur vertical pour être utilisées comme élément de sélection d'une cellule PCRAM intégrée au sein d'une architecture crossbar. / In the past few years, the increasing demand for high quality non-volatile memory (NVM) devices, leads to the developpment of NOR Flash and NAND Flash technologies, which are now the two main NVM players. However, because of some limitations such as performance degradation and limited cost reduction, the scaling of these technologies will reach in the next few years. Therefore, new NVM technologies are under development and among them, phase-change memory (PCM) technology has attracted strong interest and is now became one of the most promising candidates in order to replace Flash technologies, especially NOR Flash technology, and to address new memory markets, such as storage-class-memory market. However, in order to fully take their role in the memory arena, some performances of the PCM technology have to be improved. Therefore, during this PhD, we have tried to improve PCM devices electrical performances by reducing both programming currents and energy consumption while increasing high-temperature data-retention. To this extent, we have studied innovative device structure and alternative phasechange material. Moreover, using innovatives solutions, we show that our PCM devices could store data during the soldering step of the memory chipset. Finally, we have conceived, developed and validated, a process flow in order to make 1D1R PCM cell with Silicon-based vertical PN diodes, proving the relevance of this selector for PCRAM-based crossbar architecture.

This work deals with the laser diode soldering. The theoretical part summarizes general and acquired findings about soldering technology and materials that occur in this process. It also describes factors that affect the reliability of solder joints. It is closely focused to the shaping of the solder joint and structure of intermetallic layer. The practical part of this work is focused on the design of equipment for laser diode soldering and subsequent shaping of the samples. The quality of soldered joint is compared against the quality of joint created using re-flow technology - remelting in in-line smelter. The structure and thickness of the intermetallic layer, the number and shape of the voids in the solder joints are compared.

Purpose: To evaluate the tensile strength properties of Rx Naturelle Plus and Option (high-palladium) alloys on soldered connectors under simulated preceramic and postceramic soldering conditions. Materials and methods: Eighty cylindrical castings were fabricated (40 using Rx Naturelle Plus alloy and 40 using Option alloy). The 40 castings for each alloy were subdivided into 2 groups of 20 each. In the first group, castings for each alloy were randomly paired and soldered with SMG2 solder to produce 10 preceramic test connector specimens for each alloy. In the second group, castings were similarly paired and soldered with 490 fine solder to produce 10 postceramic test connector specimens for each alloy. Each solder connector was subjected to tensile force until failure using an Instron testing machine. Statistical analysis using a Wilcoxon Rank Sums Test was performed.Results: No significant difference was found between the mean connector strength for Rx Naturelle Plus preceramic solder (mean tensile failure stress, 50,000 Psi; STD, 11,250) compared to Option preceramic solder (mean tensile failure stress, 59,700.4 Psi; STD, 16,350) (p= 0.1202). However, the connector strength for Rx Naturelle Plus postceramic solder (mean tensile failure stress, 37,800 Psi; STD, 32,450) was significantly lower than the Option postceramic solder (mean tensile failure stress, 45,300 Psi; STD, 17,550) (p= 0.0407). Not only did Rx Naturelle Plus postceramic solder connectors show evidence of lower strength, but also an increased variation among specimens.Conclusions: Rx Naturelle Plus solder connectors provided better strength with the preceramic are opposed with the postceramic connectors. For postsolder connectors, Rx Naturelle Plus alloy had less acceptable strength and a wider variation, suggesting it is more technique sensitive than Option alloy connectors.

Este estudo avaliou a precisão de duas técnicas de união, a brasagem e a soldagem a laser, em estruturas metálicas de uma prótese clássica de Brånemark. Dez estruturas fundidas em NiCr foram segmentadas em 4 partes e analisadas no MEV em pontos pré-estabelecidos, vestibular e proximal, totalizando 8 pontos de análise para cada estrutura. Na primeira fase, foi mensurada a fenda marginal existente entre o análogo do implante e o abutment UCLA antes da união destes segmentos através da brasagem e da soldagem a laser. Após esta análise inicial, as 10 estruturas foram divididas aleatoriamente em dois grupos. O grupo que seria unido pelo processo da brasagem, utilizando maçarico gás/oxigênio, apresentou uma fenda marginal média de 5,94µm, já o grupo que seria unido através da soldagem a laser, uma fenda marginal média de 7,22µm. Os segmentos de cada estrutura metálica foram parafusados com 10Ncm aos respectivos análogos da plataforma de trabalho e unidos com resina acrílica Pattern Resin LS (GC America Inc, USA). Após a polimerização da resina, a estrutura foi desparafusada e submetida ao processo da brasagem ou da soldagem a laser e analisada no MEV nas mesmas posições pré-estabelecidas antes da união. Esta análise foi realizada na mesma plataforma de trabalho. Para tal, os quatro parafusos de fixação foram rotacionados até que fosse detectada uma leve resistência. Neste momento, somente o parafuso de uma das extremidades recebeu um torque de 10Ncm e os demais parafusos foram soltos. A média das fendas marginais após o processo da brasagem passou a ser de 18,80µm e a média das fendas marginais após a soldagem a laser passou a ser de 12,38µm. A análise de covariância mostrou que a diferença das fendas depois e antes da união através da brasagem foi maior que a diferença das fendas obtidas através da soldagem a laser (p = 0,001). Apesar da brasagem apresentar uma distorção significativamente maior quando comparada à soldagem a laser, ambas mostraram valores de fenda marginal clinicamente aceitáveis. No entanto, ficou evidente a facilidade de execução da técnica a laser em relação à brasagem, principalmente no que tange ao tempo necessário para a realização de cada uma delas. / In this study we assess precision of two union techniques, brazing and laser welding, in metallic structures of a Brånemark classical prosthesis. Ten structures cast in NiCr were segmented in four parts and analyzed in the SEM in pre-established points, vestibular and proximal, in a total of 8 analysis points for each structure. In this first phase, we measured the marginal fissure between the implant analogous and the UCLA abutment before the union of these segments using brazing and laser welding. After this initial analysis, we randomly divided the ten structures in two groups. The group that would be united by the process of brazing, using gas/oxygen blowpipe, presented an average marginal fissure of 5,94µm and the group that would be united by laser welding, an average marginal fissure of 7,22µm. The segments of each metallic structure were screwed with 10Ncm to the respective analogous of the work platform and united with acrylic resin Pattern Resin LS (GC America Inc., USA). After polymerization of the resin, the structure was unscrewed and submitted to process of brazing or laser welding and analyzed in the SEM in the same positions pre-established before the union. This analysis was made in the same work platform. To do so we rotated the four fixation screws until we felt a light resistance. At this moment, only the screw of one of the edges received a torque of 10Ncm and the other screws were released. The average of the marginal fissures after the brazing process was 18,80 µm and the average of the marginal fissures after the laser welding process was 12,38µm. The analysis of the covariance showed that the difference of the fissures after and before the union using brazing was bigger than the difference of the fissures obtained with the laser welding (p = 0,001). Despite the fact that the brazing presents a distortion significantly bigger when compared to the laser welding, both techniques showed clinically acceptable values of marginal fissures. However, it is clear how easy the execution of the laser technique is in relation to the brazing, mainly in relation to the time that is needed for each technique.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-12-23T12:17:06Z No. of bitstreams: 1 Tiago de Freitas Machado_.pdf: 13489744 bytes, checksum: 639cbc0fc0de3f47a3c757ff594540e0 (MD5) / Made available in DSpace on 2016-12-23T12:17:06Z (GMT). No. of bitstreams: 1 Tiago de Freitas Machado_.pdf: 13489744 bytes, checksum: 639cbc0fc0de3f47a3c757ff594540e0 (MD5) Previous issue date: 2016-09-15 / itt Chip - Instituto Tecnológico de Semicondutores da Unisinos / O processo de soldagem de esferas em componentes do tipo esferas organizadas em matriz do inglês BGA, ball gris array é crítico para o encapsulamento de semicondutores pois uma falha pode gerar rejeitos e retrabalhos indesejáveis ao desempenho da produção. O processo atual da empresa de encapsulamentos analisada apresentou, de forma acumulada, entre os meses de janeiro a junho de 2015 uma taxa de 1220 defeitos por milhão de unidades produzidas, relacionadas ao modo de falha denominado tamanho da esfera com o código SB003. Matérias primas alternativas para aplicação em processo de soldagem de esferas em encapsulamento de semicondutores de diferentes fabricantes, podem apresentar melhor desempenho com relação a esta ocorrência. A redução das perdas de material e de defeitos no processo de soldagem de esferas é essencial para que uma empresa de encapsulamento de semicondutores se mantenha competitiva financeiramente no mercado tanto nacional quanto internacional. O objetivo deste trabalho foi avaliar através de análises de laboratório e aplicações práticas, quatro opções de fluxos de solda solúveis ou parcialmente solúveis em água. Foram comparadas as características de viscosidade, índice de acidez, pH e perda de massa através de TGA do inglês thermogravimetric analysis, aprimorando o conhecimento intrínseco sobre este material e seu comportamento nesta etapa. Foi analisado o impacto dos diferentes fluxos de solda no desempenho da soldagem, realizando a observação da ação do fluxo em um forno de refusão e a habilidade de realinhar esferas de solda fora de posição que impactam na redução da ocorrência de defeitos. Obteve-se como resultado o fluxo A com melhor performance para realinhamento, 9,58% das esferas foram reposicionadas, perda de massa gradual e menos abrupta que os demais. / The process of soldering spheres in ball grid array components, called BGA, is critical to the semiconductor packaging, because one failure can generate rejects and undiserable reworks to production performance. The current process of the packaging company analyzed presented, in accumulated form, between the months of january and june of 2015 the defect rate of 1220 defects per million of produced units, related to the failure mode denominated ball size with the code SB003. Alternative raw material for solder sphere process applied to semiconductor packaging of different manufacturer could show better performance related to these occurrence. The reduction of material waste and defects reduction in the soldering spheres process is essential to keep a semiconductor packaging company competitive financially both in the national and international market. The objective was to evaluate through laboratory analysis and practical applications four options of soldering flux water and non-water soluble. Characteristics were compared of viscosity, acidity level, pH and mass loss through thermogravimetric analysis TGA improving the intrinsic knowledge about this material and its behavior in the step. The impact was analyzed of different solder flux performance on soldering, performing observation of the flux action on the reflow oven and the ability to realign the solder spheres misplaced that impact on the reduction of the occurrence of defects. It was obtained as result the flux A with better performance of realignment, 9.58% of misplaced spheres were repositioned, present gradual mass loss and less abrupt than the others.

Embedded active and passive devices has been increasingly used by in order to integrate more functions inside the same or smaller size device and to meet the need for better electrical performance of the component assemblies. Solder joints have been used in the electronic industry as both structural and electrical interconnections between electronic packages and printed circuit boards (PCB). When solder joints are under thermal cyclic loading, mismatch in coefficients of thermal expansion (CTE) between the printed circuit boards and the solder balls creates thermal strains and stresses on the joints, which may finally result in cracking. Consequently, the mechanical interconnection is lost, leading to electrical failures which in turn causes malfunction of the circuit or whole system. When a die is embedded into a substrate, Young's modulus of the die is larger than one of the core of the substrate and the CTEs of the die is smaller than those of the substrate. As a result, mismatch in coefficients of thermal expansions (CTE) between the substrate with the embedded device and the solder balls may increase. In the present study, finite element method (FEM) is employed to find out the stress and strain distribution of ball grid array(BGA) solders under thermal cycling. The ANAND model for viscoplasticity is employed for this purpose.

Solder joints serve as both mechanical and electrical connections between elements in a package. They are subjected to shear strains generated as a result of the different behaviors of the elements in the package (tension and compression) due to the differences in coefficients of thermal expansion during service conditions. Some of the causes of solder joint failures are due to the following: Vibration: small rapid displacements of parts of the assembly. This is not necessarily an issue with electronic components but larger parts like automobiles. Humidity: the package being exposed to water or ionic species can undergo corrosion if an electrical bias exists resulting in electrical opens or electrical shorts if the corrosion products are electrically conductive. Thermal Aging: this occurs during the lifetime of the solder interconnects, the package can be exposed to high ambient temperature or high dissipated heat during use. The micro-structure of the solder joint becomes more coarse and brittle. Mechanical Shock: the package undergoes shock during a short term exposure to high loads. Thermo-mechanical fatigue: this type of failure arises as a result of the solder joints going through cyclic strains, due to different coefficients of thermal expansion of individual components in the package during service. The most prevalent long-term reliability issues that can cause interconnect failure are thermal aging and thermo-mechanical fatigue. This study aims to evaluate the reliability of solder joints using finite element method, considering solder joint failure due to thermo-mechanical fatigue. Three variations of the BGA (Ball Grid Array) package are evaluated using the finite element analysis. The SAC305 series lead (pb) free alloy of 96.5% tin, 3% silver, and 0.5% copper is employed for this study.

Thesis (M.S.)--State University of New York at Binghamton, Department of Physics, 2006. / Includes bibliographical references.