3D chip stacking with C4 technology (original) (raw)
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3D Chip Stacking Technology with Low-Volume Lead-Free Interconnections
2007
In this paper a three-dimensional (3D) chip stacking technology using fine-pitched interconnects with lead-free solder is described. Different interconnect metallurgies such as Cu/Ni/In, Cu/In and Cu/Sn were considered and the bonding conditions to optimize the bonding parameters were determined. The effect of intermetallic compound (IMC) formation on the mechanical properties of the joins is discussed. Unlike standard 100-micron C4 solder balls, very small solder volumes (< 6 microns high) were investigated. The mechanical properties were evaluated by shear and impact shock testing, while scanning electron microscopy (SEM) and optical microscopy were used to study the morphology of the IMC layers in solder joins before and after annealing. It was found that Cu/Ni/In and Cu/In interconnections have slightly lower shear strength per bump. While these values were lower than the Cu/Sn joins, the Cu/Ni/In chips passed the impact shock test for a simulated heat sink mass of 27 g/cm2. The reasons for the differences in reliability of these metallurgies are discussed. 3D chip stacking using two-layers of chips with fine-pitch lead-free interconnects was demonstrated. The resistance of link chains comprising through-vias, lead-free interconnects and Cu links were measured using a 4-point probing method. The average resistance of the through-via including the lead-free interconnect was 21 mOmega.
3D chip-stacking technology with through-silicon vias and low-volume lead-free interconnections
Ibm Journal of Research and Development, 2008
Three-dimensional (3D) integration using through-silicon vias (TSVs) and low-volume lead-free solder interconnects allows the formation of high signal bandwidth, fine pitch, and short-distance interconnections in stacked dies. There are several approaches for 3D chip stacking including chip to chip, chip to wafer, and wafer to wafer. Chip-to-chip integration and chip-to-wafer integration offer the ability to stack known good dies, which can lead to higher yields without integrated redundancy. In the future, with structure and process optimization, wafer-to-wafer integration may provide an ultimate solution for the highest manufacturing throughput assuming a high yield and minimal loss of good dies and wafers. In the near term, chip-to-chip and chip-to-wafer integration may offer high yield, high flexibility, and high performance with added timeto-market advantages. In this work, results are reported for 3D integration after using a chip-to-wafer assembly process using 3D chip-stacking technology and fine-pitch interconnects with leadfree solder. Stacks of up to six dies were assembled and characterized using lead-free solder interconnections that were less than 6 lm in height. The average resistance of the TSV including the lead-free solder interconnect was as low as 21 mX.
3-D Stacking of Ultrathin Chip Packages: An Innovative Packaging and Interconnection Technology
Ieee Transactions on Components Packaging and Manufacturing Technology, 2013
In order to increase the functionality of electronic devices, while reducing the overall size and weight of the electronic chip packages, electronic chip packages can be combined into a 3-D assembly. In this field, we present a technology for stacking multiple chip packages, resulting in total volume almost equal to that of a single bare die. The technology is based on batch-processed ultrathin chip packages (UTCPs) with a fine pitch metal fan-out. Package-on-package technology enables stacking of UTCPs by vacuum lamination, followed by throughhole interconnection technology for making contacts to the metal fan-out of the embedded UTCPs within the stack. The individual chip packages can be tested before stacking.
Three dimensional chip stacking using a wafer-to-wafer integration
2007 IEEE International Interconnect Technology Conferencee, 2007
A three-dimensional (3D) wafer-to-wafer integration technology has been developed using face-to-face dielectric wafer bonding, followed by wafer thinning and backside interconnect formation. The key technologies required for this integration include: reliable defect free direct dielectric wafer bonding, precise wafer-to-wafer alignment, backside thinning, deep inter-strata via (ISV) formation, and wafer patterning alignment across strata. Electrical measurements indicate continuity of ISV chains for all but the smallest vias.
Three-Dimensional System-in-Package Using Stacked Silicon Platform Technology
IEEE Transactions on Advanced Packaging, 2005
In this paper, a novel method of fabricating threedimensional (3-D) system-in-package (SiP) using a silicon carrier that can integrate known good dice with an integrated cooling solution is presented. The backbone of this stacked module is the fabrication of a silicon carrier with through-hole conductive interconnects. The design, process, and assembly to fabricate silicon through-hole interconnect using a wet silicon etching method is discussed in this paper. The process optimization to fabricate silicon carriers with solder through-hole interconnect within the design tolerance has been achieved. The design and modeling methodology to optimize the package in terms of electrical aspects of the stacked module is carried out to achieve less interconnect parasitics. An integrated cooling solution for 3-D stacked modules using single-phase and two-phase cooling solutions is also demonstrated for high-power applications. Known good thin flip-chip devices with daisy chain are fabricated and attached to the silicon carrier by flip-chip processes making it a known good carrier after electrical testing. Individual known good carriers are vertically integrated to form 3-D SiP.
56th Electronic Components and Technology Conference 2006, 2006
This paper reports the current status of a novel MEMS based ultra-high density compliant interconnect technology that was proposed in the last Electronic Components and Technology Conference (ECTC) [1]. This MEMS-based interconnect, which we call Smart Three Axis Compliant (STAC) interconnects are directly fabricated onto electrical contact pads or thru-silicon vias on die at the wafer-level. These interconnects are initially bound to the die by a chemically soluble release layer. The "free" end of the interconnect is bonded to a contact pad on a package substrate or other die at the wafer level or die level, and the release layer is dissolved to free the interconnect from the substrate, thereby permitting it to accommodate relative displacements. The paper will clearly show successfully fabricated STAC interconnects at 50micron pitch on a silicon die bonded onto an ultra-thin glass die.
Through silicon via technology — processes and reliability for wafer-level 3D system integration
2008 58th Electronic Components and Technology Conference, 2008
3D integration is a rapidly growing topic in the semiconductor industry that encompasses different types of technologies. The paper addresses one of the most promising technologies which uses through silicon vias (TSV) for interconnecting stacked devices on wafer-level to perform high density interconnects with a good electrical performance at the smallest form factor for 3D architectures. Fraunhofer IZM developed a post frontend 3D integration process, the socalled ICV-SLID technology based on metal bonding using solid-liquid-interdiffusion (SLID) soldering. The SLID metal system provides the mechanical and the electrical connection, both in one single step. The ICV-SLID fabrication process is well suited for the cost-effective production of both, highperformance applications (e.g. 3D microprocessor) and highly miniaturized multi-functional systems. The latter preferably in combination with wafer-level die stacking, as e.g. Thin Chip Integration (TCI) or SnAg-microbump technologies. The fabrication of distributed wireless sensor systems (e. g. e-CUBES®) is a typical example for the need of such mixed approaches.
Three-dimensional integrated circuits
Ibm Journal of Research and Development, 2006
Three-dimensional (3D) integrated circuits (ICs), which contain multiple layers of active devices, have the potential to dramatically enhance chip performance, functionality, and device packing density. They also provide for microchip architecture and may facilitate the integration of heterogeneous materials, devices, and signals. However, before these advantages can be realized, key technology challenges of 3D ICs must be addressed. More specifically, the processes required to build circuits with multiple layers of active devices must be compatible with current state-of-the-art silicon processing technology. These processes must also show manufacturability, i.e., reliability, good yield, maturity, and reasonable cost. To meet these requirements, IBM has introduced a scheme for building 3D ICs based on the layer transfer of functional circuits, and many process and design innovations have been implemented. This paper reviews the process steps and design aspects that were developed at IBM to enable the formation of stacked device layers. Details regarding an optimized layer transfer process are presented, including the descriptions of 1) a glass substrate process to enable through-wafer alignment; 2) oxide fusion bonding and wafer bow compensation methods for improved alignment tolerance during bonding; 3) and a single-damascene patterning and metallization method for the creation of high-aspect-ratio (6:1 < AR < 11:1) contacts between two stacked device layers. This process provides the shortest distance between the stacked layers (<2 µm), the highest interconnection density (>108 vias/cm2), and extremely aggressive wafer-to-wafer alignment (submicron) capability.
3D memory chip stacking by multi-layer self-assembly technology
2013 IEEE International 3D Systems Integration Conference (3DIC)
Multi-layer 3D chip stacking by a surfacetension-driven self-assembly technique is demonstrated. After multi-layer self-assembly, memory chips having Cu-SnAg μbump and Cu-TSVs are bonded on a substrate by thermal compression to confirm electrical joining between them. In addition, we investigate the impacts of wetting properties of chip/substrate surfaces, μbump shapes, and μbump layout on alignment accuracies of self-assembly. Good electrical characteristics are obtained from the TSVμbump daisy chains in the stacked memory chips.