1.  Field of Invention
The invention relates to a package assembly, and more particularly to a thin package assembly of an electronic component capable of quickly dissipating the heat generated by the electronic component. 
2.  Related Art
Heat is generated when an electronic component is operating with electrons flowing therethrough.  The generation of heat increases the resistance and blocks the flows of the electrons so that the function of the electronic component is significantly influenced.  When the technology of manufacturing the electronic component is greatly enhanced, a line width in the electronic component is getting smaller and smaller, and the line density in the electronic component is getting higher and higher.  Thus, the heat generated by the electronic component is increased rapidly.  Taking a central processing unit (CPU) of a computer as an example, the Pentium CPU only has to be equipped with the package with the heat dissipating capability of 16 W at its early stage.  However, the heat generated in the CPU in the year of 2004 has reached 84 W, and the heat generated in the CPU in the year of 2006 has reached 98 W. If the heat cannot be removed rapidly, the temperature of the CPU of the computer is rapidly increased so that the CPU of the computer can no longer operate.  Thus, the heat dissipating ability of the substrate contacting with the CPU of the computer is a key factor for dominating whether the computer can operate normally or not. 
A typical power component, such as a solid relay, is similar to the CPU of the computer and generates a lot of heat.  Thus, the power component also dissipates the heat rapidly through the substrate contacting therewith so that it can operate normally. 
Taking a light-emitting diode (LED) as another example, various color LEDs have been gradually developed, wherein the successful development of the white-light LED has attracted considerable attention.  This is because the white-light LED can serve as a light source for an illumination lamp.  The power consumption of a road lamp with the LED light source is lower than that of a mercury lamp by 75% and is lower than that of a high pressure sodium lamp by 49%.  So, the white-light LED advantageously has the low power consumption and can significantly save the energy.  However, the white-light LED with the output power higher than 3 W has to be adopted in the application of the lamp used in the daily life and the applications such as the head light used in a vehicle.  This white-light LED with the high output power also generates a lot of heat.  However, the major barrier on the applications of the LED as the light source is that the LED cannot withstand the high temperature.  Generally speaking, the temperature of the LED cannot exceed 90° C. If the temperature of the LED is higher than 90° C., the luminance thereof rapidly deteriorates.  So, the rapid heat dissipating ability of the heat dissipation substrate in contact with the LED has become a greatest challenge for determining whether the LED can become the illumination light source or not.  This also specifies that the development of the heat dissipating substrate has played an important role on the applications of the LED as the light source. 
In order to satisfy the miniaturized requirement of the current 3C electronic products, the substrate contacting with the CPU of the computer, or the power component or the LED has to satisfy the following fundamental requirements. 
First, the material must have a high heat conductivity to dissipate the heat rapidly. 
Second, the material must have the high resistivity in order to prevent the high power electronic component from being short-circuited. 
Third, the substrate preferably has to be as thin as possible after the above-mentioned conditions are satisfied. 
At present, the heat dissipating mechanisms of the electronic components, which are frequently used, include heat dissipating fins and a heat pipe accompanied with fans in order to dissipate the heat generated by the high power electronic components.  However, such heat dissipating structure has a larger thickness, and the applications in designing a miniaturized 3C electronic product are thus hindered.