Multi-chip module

From the silicon area perspective, the MCM scheme is similar to the 2.5-D scheme except the following 2 factors. 

High test cost due to die carriers Due to the difficulty of test access, 

MCMs often needs very expensive die carriers to achieve high fault coverage. In this work, the carrier cost as well as the extra test preparation time is modeled as having a cost equal to a testing time of 60 seconds1321. As a result, the silicon area of MCM can be computed as  

Based on the above analysis, the silicon areas of the MCM implementation for different numbers of dies can be computed and shown in Fig. 2.4. 

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Mullite fibers Multhiomyan Multiblock copolymers Multi chip modules... 

Eden, R. C., Application of Synthetic Diamond Substrate for Thermal Management of High Performance Electronic Multi-Chip Modules, in Applications of Diamond Films and Related Materials, (Y. Tzeng, etal., eds.), Elsevier Science Publishers, pp. 259-266(1991)... 

The above concept of forming adhesive bonds in the solid state has been used to demonstrate the possibility of the parallel processing of a multi-chip module substrate, consisting of a multilayered polymer substrate with circuitry embedded on each polymer layer via lithographic processing [43], In this case, it is essential that the polymeric layer retains its dimensional stability so that registration and interconnections between the layers can be achieved using a Pb-Sn solder (see Fig. 28). A copolyester which appears to be ideally suited for this purpose is the 4/1 PHBA/BPT which melts at 320 °C in the randomized form... 

C-N thin films could be an attractive diamond-like coating material for thermal management in multi-chip modules and micro-scale devices [35]. The field-emission properties of C-N thin films were studied, and indicated an enhancement in the emitted current density [36]. It has been predicted that this material would, as a consequence, have a wide range of potential applications, such as in electronic packaging and wear protective coatings for magnetic storage devices [37]. 

At a microscopic level the contact surface is restricted by peaks and valleys and even highly polished surfaces may exhibit a high peak to valley ratio. This makes it necessary to use an extremely flat contact surface between the heat source and thermal spreader to guarantee an efficient transfer of heat. Chemical vapor deposition diamond with a thickness of 1000 pm has been used for Multi Chip Modules (MCM) for this purpose. Heat spreaders are used in the electronic industry for IC packaging and solid-state lasers. 

Compactness - The whole spectrometer will be implemented on a few 10 X 10 mm and 5X5 mm chips mounted on the multi-chip module. 

Fig. 1 shows the block diagram of the integrated spectrometer under development. The superconducting part of the receiver consists of two chips mounted on a multi-chip module (MCM). 

Multi-chip modules, in which chips are attached with TAB directly to an interconnection substrate, typically silicon or aluminum nitride or other ceramics, represent an emerging technology. The module interconnect circuits are generated with IC fabrication technology, but at a relatively modest level of resolution. Typically, as shown in Figure 6, the substrates can include power and ground planes plus one or more signal planes, and low dielectric constant interlayer materials such as polyimides. These modules, which have feature sizes ca. 5 to 50 pm, and which are mounted directly on the PC board or serve as the board itself,... 

In Chapter 2, we present a unified cost analysis among five different integration schemes monolithic System-on-Chip, Multiple-Reticle-Wafer, Multi-Chip Module, 2.5-D integration, and 3-D integration. Our results proved that the 2.5-D integration scheme could be the most cost efficient under a group of reasonable assumptions. 

Abstract Besides the dominant monolithic VLSI integration paradigm, many non-monolithic schemes have already been developed in the past. Typical such schemes include wafer scale integration or multi-reticle wafer, multi-chip module, and 3-D integration. In this chapter we compared these different schemes in a unified cost analysis framework. Our model takes a few parameters extracted from representative fabrication and evaluates the cost efficiency. Our analysis proves that the proposed 2.5-D out significantly outperform other integration paradigms from a cost perspective. 

Keywords 2.5-D integration, monolithic VLSI integration, multi-reticle wafer, multi-chip module, 3-D integration, yield, silicon area, fault coverage. 

Multi-chip module (substrate low-temperature, co-fired ceramic, LTCC)... 

Conductive Adhesives. Isotropically electrically conductive adhesives (ICAs) are widely used in the electronics industry when high-temperature soldering processes are unsuitable. Typical applications include silicon die attachment, component attachment in multi-chip modules (MCMs), surface mounted printed circuit board repair, and elec-tromagnetic/radio frequency (EMI/RFI) shielding. 

Epoxies form the basis of products in the multi-chip module (MCM) bonding and surface mount technology (SMT) repair areas. Two-pack room-temperature products (amine cure) are common in repair applications. Two-pack systems with acid anhydride... 

Polyimide films are used in a variety of interconnect and packaging applications including passivation layers and stress buffers on integrated circuits and interlayer dielectrics in high density thin film interconnects on multi-chip modules and in flexible printed circuit boards. Performance differences between poly-imides are often discussed solely in terms of differences in chemistry, wiAout reference to the anisotropic nature of these films. Many of the polyimide properties important to the microelectronics industry are influenced not only by the polymer chemistry but also by the orientation and structure. Properties such as the linear coefficient of thermal expansion (CTE), dielectric constant, modulus, strength, elongation, stress and thermal conductivity are affected by molecular orientation. To a lesser extent, these properties as well as properties such as density and volumetric CTE are also influenced by crystdlinity (molecular ordering). 

In this way high reliability of PI interconnect ICs was confirmed in the market, and application of PI to microelectronics rapidly e q>anded. Fig. 3 summarizes the application of Pis to microelectronics in chronological order (5). They include a-ray shield of memory device, interlayer insulation of thin film facsimile thermal head, thin film magnetic head and so forth. Out of these applications, this paper introduces the recent progress of the application to LSI, Liquid Crystal Display, Multi Chip Module and Optical Wave Guide. 

PI has began to be applied to multi chip module, which can reduce the machine cycle of computer. Cross section of tjpical MCM is shown in Fig. 11 (12). 5 layers of metallization insulated by 15 to 20 ju.m thick PI film is formed on ceramic wiring board. Table 9 is the results of the evaluation of various Pis for MCM (13). Among them, low stress PI, namely low thermal expansion PI, seems to be best balanced except for adhesion and planarity. In the following, recent works to improve these properties of low thermal expansion PI will be introduced. 

Figure 11. Cross section of PI thin film multi chip module.

Figure 12. Three adhesion interfaces in PI multi chip module.

Aromatic polyimides have found wide application in the microelectronics industry as alpha particle protection, passivation, and intermetallic dielectric layers, owing to their excellent thermal stability, mechanical properties and dielectric properties (7-5). Many microelectronic devices, such as VLSI semiconductor chips and advanced multi-chip modules (5), are composed of multilayer structures. In multilayered structures, one of the serious concerns related to reliability is residual stress caused by thermal and loading histories generated through processing and use, since polyimides have different properties (i.e., mechanical properties, thermal expansion coefficient, and phase transition temperature) from the metal conductors and substrates (ceramic, silicon, and plastic) com-... 

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