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Vendors - Components There are four categories of parts used in MCMs - packages, interconnects, integrated circuits, and passive components (resistors and capacitors). Package and interconnect vendors are generally available to support MCM needs, as are vendors of passive components. However, availability of unpackaged integrated circuits for use in MCMs is a very big issue. The low purchase quantities by MCM vendors carry little clout with IC manufacturers and die are sometimes difficult to get. Even if available, unpackaged die can be expensive and have lengthy delivery times. Vendors and solutions to these issues are discussed in the sections below.
Integrated CircuitsIndividual bare die are need to build an MCM. So, the schematic designer would take care to design the MCM using only parts which are available in bare die format. It might be expected that the bare die price would be less than that of a packaged, tested die. However it often the case that the bare die are more expensive because the IC manufacturer has to provide special, manual handling of the wafer outside of the normal manufacturing flow.Either way, delivery schedules can be 12-16 weeks - depending on the inventory available at the time the purchase order is released. Also, the die will have only gone through wafer probe testing - usually a single temperature, limited-speed test. The yield of the devices at full speed/temperature are not guaranteed by the IC manufacturer, so it is typical that additional devices must be ordered to use in reworking any devices that fail during the MCM manufacturing process. In general, device yields are above 90%, but even at that level some amount of MCM rework is certain. Often, because bare die sales are a very small part of the overall electronics industry many IC manufacturers are reluctant to sell die. In good economic times there is less cooperation and bad economic times the IC manufacturers are more cooperative. In many cases, the IC manufacturers are not willing to sell die, but are willing to sell wafers. Sometimes you can buy a single wafer, but often you have to buy an entire lot - usually about 12 wafers. At $5K-$10K per wafer, the minimum buy requirements for a small purchase of die can be prohibitive. Even if a decision is made to purchase a wafer there can still be delivery times of several months. Since there is risk in the saw process (singluation of the die from the wafer), a minimum of two wafers is often purchased to avoid the schedule risk of a problem occuring during dicing. Several companies have been created to assist MCM designers in acquiring bare die. These companies provide the following types of service:
The following companies provide bare die services as just described:
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PackagesThere are a variety of packages configurations used by MCM designers. In most cases, the package is purchased by an outside vendor who specializes in package design and fabrication.As is discussed in more detail elsewhere at this site, package variations include:
As you might expect from the wide variation in package configurations, most companies cannot provide all types and will typically specialize on a few of the options. The following manufacturers provide packages used in the assembly of MCMs:
ResistorsMost electronic schematics include both resistors and capacitors. In the case of resistors, the most common function is to provide pullup/pulldown functions for digital ICs, or for use in linear timing circuits.The resistors, often called chip resistors, used in MCMs are typically small blocks of resistive material with connection points on both ends. Typically, the ends are simply metallized to allow for solder attachment of the resistor. In some cases, the ends have metallized pads suitable for using wirebonds to make electrical attachment to the interconnect. Key parameters include resistance value, resistance tolerance, allowable power dissipation, and temperature coefficient of resistance (how resistance varies over temperature) Like their PWB counterparts, chip resistors come in a wide range of resistance values and tolerance precision. The 5% and 1% tolerance values, dissipating 1/10 or 1/16 watts are the most common chip resistors. Body sizes of 80x50 mils and 60x30 mils (usually writtenas 0805 and 0603) are commonly used, although the industry is moving to smaller body sizes such as 0402 and 0201. Bodies of the resistors typically consist of 96% ceramic insulator material with ruthenium or tantalum oxides as the resistive materials. Termination material may be nickel chromium or tantalum nitride. Precision resistor fabrication may involve the use of YAG lasers to trim the resistors to exact values. Each of the computer, consumer audio/video, and telecom industries account for approximately 25% of the roughly 500 billion chip resistors sold each year (about $1B total market). The vast majority (over 90%) of all chip resistors are made in Eastern countries, particularly Japan and Taiwan. While costs can vary depending on performance parameters, the price in larger quantities can be very low - down to about $0.003. The resistors just described are also used extensively in commercial electronic products. Since they are essentially sealed units, these resistors are suitable for both commercial and military environments. The following list shows several of the major suppliers of chipo resistors. CapacitorsMost electronic schematics include both resistors and capacitors. In the case of capacitors the most common function is to provide power supply filtering or for use in linear timing circuits.The capacitors, often called chip capacitors, have a more complicated structure than chip resistors. Capacitors are typically multi-layer structures, where each layer provides some level of capacitance and where many layers are needed to build up to the desired level of capacitance. Like chip resistors, chip capacitors are typically metallized to allow for solder attachment of the capacitor. Key parameters include capacitance value, capacitance value tolerance, temperature coefficient of capacitance, breakdown voltage, dissipation factor (loss tangent) and insulation resistance. Unlike resistors, however, capacitors are typically purchased with wider tolerances - 5%-20%. The dominant use of chip capacitors is as power supply filters, which means that two ranges of values are often use. Values of 0.1uf and 0.01uf, in ceramic construction are used to filter high frequencies. Value of 1uf and 10uf, using tantalum construction are used to provide low frequency filtering. Both are typically used in a design. Like resitors, body sizes of 80x50 mils and 60x30 mils are popular for the ceramic capacitors, whereas the tantaulum capacitors typically have larger body sizes. Capacitors are not typically trimmed to adjust capacitance value. The one exception are 1% (or tighter) capacitors intended for using in RC timing circuits. Filtering applications generally do not require tight tolerances. Chip resistor and chip capacitor markets are similar in size - about 500 million units a year but capacitor prices are generally higher than chip resistor prices. Costs can vary depending on performance parameters, but in larger quantities prices can be just a few cents each. In smaller quantities, however, prices in the $1-$2 range are not unusual. Chip capacitors are also used extensively in commercial electronic products. Since they are essentially sealed units, chip capacitors are suitable for both commercial and military environments. The following list shows several of the major suppliers of chip capacitors.
OtherThere are other components which MCM vendors use. For example, transformers, crystal oscillators, thermistors, and more. Usually these devices are specific to particular types of applications and products. If an MCM vendor uses them, they will probably use them often whereas other MCM vendors may never use them at all.The following list is a sampling of vendors that supply components which can be used in MCMs. OrganizationsAs with most industries, vendors of components have formed organizations which work to encrease business opportunities for its member companies.The following list gives key component industry associations.
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