Method for forming LED by a substrate removal process

DETAILED DESCRIPTION Some sample embodiments of the invention will now be described in greater detail.
Nevertheless, it should be recognized that present invention can be practiced in a wide range of other embodiments besides those explicitly described, and the scope of the present invention is expressly not limited expect as specified in the accompanying claims.
Then, the components of the different elements are not shown to scale.
Some dimensions of the related components are exaggerated and meaningless portions are not drawn to provide a more clear description and comprehension of the present invention.
The essence of the present invention is to form a metal layer by a chemical method and a physical method, and the metal layer is employed as a permanent substrate to replace the Al2O3 or SiC substrate in the conventional arts.
Accordingly, the conductivity and the cooling effect of substrate can be efficiently increased, and further the pads are formed on opposite side, so only one pad need to bond in package process.
Moreover, the LED having the metal substrate is a high power LED due to the metal substrate has well cooling effect and the LED can operated with high current.
The chemical method and physical method mentioned above comprise electroplating, electroless plating, CVD (chemical vapor deposition), (PVD) physical vapor deposition (as evaporation or sputtering deposition), and so on.
These methods can control the thickness of the metal substrate and do not need the polishing and cutting process, and hence the complexity of LED process is also reduced.
Furthermore, a reflecting layer is formed between the metal layer and the LED chip (or the LED epitaxial layer) to efficiently guide the light emitted by the LED chip to the same (outward) direction for increasing the illumination of the LED.
According to the aforementioned essence, the present invention discloses preferred embodiments for illustrating the method of forming the LED having the advantages mentioned above.
FIG.
2A to FIG