Multichip module

Metal powder—glass powder—binder mixtures are used to apply conductive (or resistive) coatings to ceramics or metals, especially for printed circuits and electronics parts on ceramic substrates, such as multichip modules. Multiple layers of aluminum nitride [24304-00-5] AIN, or aluminay ceramic are fused with copper sheet and other metals in powdered form. The mixtures are appHed as a paste, paint, or slurry, then fired to fuse the metal and glass to the surface while burning off the binder. Copper, palladium, gold, silver, and many alloys are commonly used. 

A substrate is a robust element that provides mechanical support for the die. It can be mounted with more than one die such packages are called multichip modules. Because parasitic capacitance effects are directiy proportional to the dielectric constant, substrate material should have a low dielectric constant. 

Single-crystal sUicon has also been employed as substrate material, particularly in multichip module (MGM)-Si appUcations. As a substrate, sUicon offers good thermal conductivity and matches the GTE of the devices mounted on it it does, however, have a relatively high dielectric constant and is very britde. 

M. Pecht, Integrated Circuit, Hybrid, and Multichip Module Package Design Guidelines M Focus on Keliability,]ohxi Wiley Sons, Inc., New York, 1994. 

Mucor miehei, 84 Multiblock copolymers, 7-8, 26 Multichip modules, dielectrics for, 270-271 Mylar, 21... 

Gillot C, Schaeffer C, Bricard A (1998) Integrated micro heat sink for power multichip module. IEEE Trans Ind Appl 36(1) 217-221... 

Pricing as well as reliability considerations have led to an almost exclusive use of Si-based (i.e. Si and SOI) micro machined devices. Packaging and assembly has focused on ceramics (A1203, AIN, Low Temperature Co-fired Ceramics LTCC), Printed Circuit Board (PCB-) and Surface Mount Device (SMD-) technology and multichip modules (MCM s). 

Advances in the speed and complexity of integrated circuits and multichip modules (MCMs) have created a demand for the development of high-density... 

Stability for use in optical interconnects. In the near future, optoelectronic integrated circuits and optoelectronic multichip modules will be produced. Materials with high thermal stability will thus become very important in providing compatibility with conventional 1C fabrication processes and in ensuring device reliability. Polyimides have excellent thermal stability so they are often used as electronic materials. Furuya et al. introduced polyimide as an optical interconnect material for the first time. Reuter et al. have applied polyimides to optical interconnects and have evaluated the fluorinated polyimides prepared from 6FDA and three diamines, ODA (3), 2,2-bis(3-aminophenyl) hexafluoropropane (3,3 -6F) (4), and 4,4 -6F (2), as optical waveguide materials. 

W.Y. Lin, Embedded Capacitors for Electronic Circuits Based on Flexible Laminate Multichip Module/Printed Circuit Boards, Contract DM1 9561712, NSF SBIR Phase 1 Grant, 1996. 

One example of a successful polymer CMP program is for the fabrication of ILD layers for multichip modules (MCM) at MCC. Figure 8.7 shows schematically a cross section view of an MCM interconnection system. Low dielectric constant ILDs are required in MCMs because the long interconnect lengths lead to long delays. In the MCC process, the polyimide is deposited by... 

Pautsch, G. and Bar-Cohen, A., 1999, Thermal Management of Multichip Modules with Evaporative Spray Cooling, ASME Publication, EEP-Vol 26-1, Advances in Electronic Packaging -1999, Vol 1, Proceedings, InterPack 99, Maui, Hawaii... 

Doane, D.A. in Multichip Module Technologies and Alternatives. The Basics. 

Figure 6. Multichip module system. (Courtesy of Honeywell, Inc.)...

Rigid-rod polymer films made from PBO and PBZT are being developed because they provide important performance improvements over competing materials such as fiber reinforced composites and metals. Table I summarizes some of the highest payoff applications. Thin PBZT films combined with low dielectric constant resins are being developed for multilayer circuit boards and multichip modules to increase interconnection density and speed with matched circuit impedance and reduced crosstalk. 

In the future, the very hot IC s will be packaged in a thermally efficient module or in a multichip module, which will then be mounted on a more conventional substrate. 

Fine line circuitry can be obtained from current materials, and particularly with thin copper foils. Additive systems can take this further. In addition, multichip modules may be used for the most severe situations ... 

When molded or premolded packages cannot be used for whatever reason, for example, a need for hermetic sealing, modules using ceramic substrates (or PCB-printed circuit board) offer almost unlimited flexibility. They can be used for simple multichip modules containing two or more elements (e.g., a sensing element and an evaluation circuit), may include external components, or may be used to construct complete systems. Stress-optimized package configurations for sensitive microsystems and sensors are no problem (Fig. 5.8.4). 

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