News » 2002 » Kyocera Develops an Alumina Multilayer Package With Low Resistance Routing Patterns


Kyocera Develops an Alumina Multilayer Package With Low Resistance Routing Patterns

(This document was translated from the Japanese press release.)

San Diego, CA: June 1, 2002. — Kyocera has developed a low resistance routing pattern alumina multilayer package to enable the use of a low-resistance copper type conductor for routing pattern on alumina ceramics in the semiconductor components business. The Company has already begun to accept orders for the product. The product has the advantages of a copper type conductor, which is of low resistance and excels in high frequency properties, as well as the advantages of alumina ceramics with their outstanding strength and heat dissipation, so it can increase the degree of freedom in circuit board designing. With the development of this product, which is the first for the industry, we will continue to respond to growing demands for miniaturization, multifunctions, high frequency compatibility and improvements in the operating speed of mobile communications equipment in the future.

Characteristics of the "low resistance wiring alumina multilayer package."

1. Low Resistance and Superior High Frequency Properties by Using Copper Type Conductor
Using a copper-type low resistance conductor for routing has drastically reduced the conductor resistance compared with the existing alumina multilayer package using the tungsten type conductor. Coupled with the superior high frequency properties possessed by copper type resistance, the degree of freedom of circuit design is increased, enabling further miniaturization and multifunctions in equipment.

Reference values





  Conductor resistance
Low resistance routing alumina multilayer package 3m Ohm/sq
LTCC package 3m Ohm/sq
Conventional alumina multilayer package 10m Ohm/sq

2. Great Mechanical Strength Using Alumina Ceramics
Alumina ceramics is approximately twice as strong as LTCC when it comes to three-point bending. This means that it is possible to make a thinner package with the same number of laminations or to create a package with the same thickness but with more laminations, with the result that we are able to miniaturize and slim down a circuit substrate for use in the equipment. Another benefit of this strength is that a package with metal brazing can be made.

Reference Values





  Strength in three point bending
Low resistance routing alumina multilayer package 400Mpa
LTCC package 170 ~ 200Mpa
Conventional alumina multilayer package 400 ~ 460Mpa

3. High Heat Dissipation Capacity Using Alumina Ceramics
With improvements in the number of elements (the degree of integration) integrated in one IC chip and improvements in the clock frequency for increasing the operating speed, the power consumption of the overall IC has increased drastically. With this increase in power consumption, if the temperature rises because of the heat generated by the IC chip, a number of problems will occur with the properties and performance. Alumina ceramics has thermal conductivity that is an order of magnitude higher than that of LTCC, and by performing outstanding heat dissipation, it will be able to respond to equipment miniaturization and improve its operating speed.

Reference Values





  Thermal conductivity
Low resistance routing alumina multilayer package 15W/(m.K)
LTCC package 1.2 ~ 2W/(m.K)
Conventional alumina multilayer package 14 ~ 18W/(m.K)

Background of the development
At present, the Low Temperature Co-fired Ceramics (LTCC) package is often used for modules for mobile phones. LTCC employs a conductor for routing, such as copper, which excels in high frequency properties and is of low resistance. The LTCC package, which uses a material with a low melting point such as copper as a conductor, contains considerable glass materials to keep its co-firing temperature low. This gives it superior electrical properties of the conductor, although it is inferior to the alumina multilayer package in terms of the mechanical strength of the substrate itself and heat dissipation.

On the other hand, since the alumina multilayer package, with its excellent mechanical strength and heat dissipation, has a high co-firing temperature, tungsten type material with a high melting point is used for the conductor, making it inferior to the copper type in conductor electrical properties for high frequency applications.

In recent years, the market has been demanding ever smaller and thinner mobile communications equipment with more functions and high frequency compatibility, while maintaining the electrical properties of the conductor, necessitating provision of a package that has the strength to enable reduced size with high thermal conductivity to dissipate the generated heat quickly. This is the "low resistance routing pattern alumina multilayer package" that we have developed to incorporate the advantages of both LTCC and alumina ceramics to respond to the above market demands. Going forward, particularly for the modules of mobile phones, we will be able to develop applications for next-generation telecommunications devices with high power and a large electric current, such as a package for high-frequency modules and a package for microwave.

San Diego-based Kyocera America, Inc. designs, manufactures and assembles a broad range of electronic packaging solutions for the telecommunications and semiconductor markets based on advanced ceramic and plastic material technologies. The company's products and services support broadband telecommunications, mobile and satellite communications, surveillance systems, sensors, automotive electronics, medical devices, computers and consumer electronic goods.

Kyocera America, Inc. has manufacturing facilities in California and Oregon, with sales offices and design centers throughout the United States. The company is a wholly-owned subsidiary of Kyocera International, Inc. of San Diego, the North American headquarters and holding company for Kyoto, Japan-based Kyocera Corporation (NYSE:KYO).

Kyocera Corporation, the group's global parent, employs 40,000 people in 25 nations and recorded consolidated net sales of 1.03 trillion yen (US $7.8 billion) during the year ended March 31, 2002.

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