1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device, and more especially, to the manufacturing method of a poly-silicon semiconductor device.
2. Background of the Related Art
Semiconductor device formed with low temperature poly-silicon layer has been widely applied to 3 C environment, and especially to the control device of flat display panel (FDP). Comparing the low temperature poly-silicon technology with the amorphous silicon technology, the low temperature poly-silicon technology can be used to make a high resolution and full color FDP because it has a greater electromigration rate, a better structure and electrical characteristics. Besides, using low temperature poly-silicon technology can combine the drive circuits of the panel and form on the glass substrate of FDP directly to reduce the pin connection, and is used to develop and produce the high quality device such as thin film transistor and charge-coupled device (CCD). The general amorphous silicon manufacture process usually uses furnace annealing, rapid thermal annealing and excimer laser annealing. In the process of the furnace annealing, the poly-silicon is deposited on the substrate directly by low pressure chemical vapor deposition under 600° C., but the annealing time is very long during the whole process of nucleation to nucleus growth. The rapid thermal annealing can reduce thermal budget but the crystallization result becomes worse. An excimer laser is used to melt amorphous silicon layer and then the amorphous silicon crystal crystallize during the processes of the excimer laser anneal. But the amorphous silicon crystal is too small due to the lack of rapid condense speed of the melting amorphous silicon.
U.S. Pat. No. 6,197,626 provides a method of forming poly-silicon by using a metal to induce an amorphous silicon layer to crystallize. The method includes the steps of providing an amorphous silicon layer with a metallic surface such as gold or nickel, heating the amorphous silicon layer to form the metal silicide surface and transform the amorphous silicon to the crystal silicon by the atomic movement of the metal silicide, and then forming the poly-silicon layer during annealing. The advantage of the foregoing method is that the poly-silicon can be formed on many types of substrates by using the low temperature manufacturing. But, in the process of the crystallizing an amorphous silicon layer induced by metal, the metal will remain in the lattice of the poly-silicon to form the metal contamination, and that will damage the electrical characteristics of the device. In order to get the poly-silicon layer with higher quality and better electrical characteristics of the device, the metal remnants in the poly-silicon must be reduced. Therefore, this patent also provide another processes, which includes to deposit a SiO2 and Si3N4 layer on the poly-silicon, to form a designed pattern via photolithography process, to implant phosphorus ions, to move the metal remnants in poly-silicon from the non-phosphorus-ion region to the phosphorus-ion region during annealing, and to remove the SiO2 layer, Si3N4 layer and unnecessary poly-silicon layer by using an isotropic etching according to the designed pattern of the device.
However this method spends much time and cost due to the additive photolithography process, three etching processes and a phosphorus ions implant process. Therefore, how to effectively reduce the metal remnants on the prerequisites of decreasing the manufacture time and cost is one of the important demands for manufacturing the semiconductor device.
One of objects of this invention is to provide a semiconductor device and a manufacturing method thereof, which forms a diffusion layer to prevent the remnant metal element from flowing back to the semiconductor film.
One of objects of this invention is to provide the semiconductor device and the manufacturing method thereof, which forms an improved diffusion layer for gettering the metal residue and a gettering material layer without using additional photolithography process on the poly-silicon layer to getter the metal residue in the metal-induced poly-silicon layer.
One of objects of this invention is to provide the semiconductor device and the manufacturing method thereof, which makes a poly-silicon layer with bigger crystal and removes residual metal from the poly-silicon layer effectively.
In order to accomplish the above objects, one embodiment of the present invention provides a manufacturing method of a semiconductor device includes the following steps. An amorphous silicon layer is formed on a substrate with an insulated surface; a catalytic metal element is imposed on the amorphous silicon layer to form a poly-silicon layer on the insulated surface by heating and catalyzing the amorphous silicon layer. A diffusion layer and a gettering material layer is subsequently formed on the poly-silicon layer in order. Then, an annealing process is proceeded for the gettering material layer and the poly-silicon layer. Finally, the diffusion layer and the gettering material layer are removed.
Furthermore, referring to
To sum up, the present invention can be applied to many difference substrates without increasing manufacturing step and production cost to manufacture the poly-silicon layer with bigger crystal and remove residual metal element in the poly-silicon layer effectively. Furthermore the present invention simplifies the manufacturing processes and enhances reliability of the semiconductor device.
Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that other modifications and variation can be made without departing the spirit and scope of the invention as hereafter claimed.
Number | Date | Country | Kind |
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95142666 | Nov 2006 | TW | national |