JPH0243772A - Manufacture of thin film transistor - Google Patents

Abstract

PURPOSE:To efficiently remove an electrode material component deposited during a plasma hydrogen treatment process without giving any damage to device so as to eliminate a leakage current and a defective wire bonding due to an electrode material component by a method wherein a plasma hydrogen treatment process is made after the formation of a source and a drain diffusion layer through a thermal diffusion material and before the removal of the thermal diffusion material. CONSTITUTION:A plasma hydrogen treatment process is made after the formation of a source diffusion layer 7 and a drain diffusion layer 8 through a thermal diffusion material 6 and before the removal of the thermal diffusion material 6. For instance, a polycrystalline silicon film 3 is formed on a quartz substrate 1 and patterned into a specified form, and then a gate electrode 5 is built through the intermediary of a gate oxide film 4, thereafter an application type diffusion material 6, whose main component is silanol, is applied onto the silicon film 3, which is subjected to a thermal diffusion for the formation of the source diffusion layer 7 and the drain diffusion layer 8 on the polycrystalline silicon film 3. Then, when the quartz substrate 1 is subjected to a plasma hydrogen treatment, an electrode material component is deposited the diffusion material 6 to form an electrode material component layer 9. Then, the diffusion material 6 is removed through an etching using fluoric acid, whereby the electrode material component layer 9 deposited on the diffusion material 6 is completely removed with the diffusion material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a thin film transistor used in a 1:1 image sensor, a liquid crystal device, etc.

[Prior Art] Conventionally, thin film transistors are manufactured by forming an amorphous silicon film on an insulating substrate, for example, a quartz substrate, and then forming the amorphous silicon film into a polycrystalline silicon film by melting and recrystallizing the film. Then, this polycrystalline silicon film is used as a semiconductor material to form a gate oxide film, a gate electrode, a source and
It is manufactured by sequentially performing the steps of forming a drain diffusion layer, forming a glabella insulating film, forming a contact hole, forming an aluminum electrode layer, and plasma hydrogen treatment.

Here, plasma hydrogen treatment is performed to fill the traps (capture levels) existing in the polycrystalline silicon film with hydrogen atoms and increase their mobility, and is usually performed using a parallel plate type plasma hydrogen treatment equipment. This is done using

[Problems to be Solved by the Invention] However, when plasma hydrogen treatment is performed using such a parallel plate type plasma hydrogen treatment apparatus, hydrogen ions collide with the surface of the electrode, and a sputtering phenomenon due to hydrogen ions occurs, causing iron, Electrode material components containing nickel, chromium, etc. as main components are deposited on the substrate, causing leakage and wire bonding defects. However, such electrode material components cannot be removed by chemical etching, and if sputter etching is performed, although it is possible to remove them, there is a disadvantage in that they damage the device.

In view of this, the present invention efficiently removes electrode material components deposited during the plasma hydrogen treatment process without damaging devices, completely eliminates leaks and wire bonding defects due to electrode material components, and improves yield. An object of the present invention is to provide a method for manufacturing a thin film transistor that can achieve the following.

[Means for Solving the Problems] The present invention provides a method for manufacturing a thin film transistor that includes a plasma hydrogen treatment step, in which the plasma hydrogen treatment step is performed by thermal diffusion after forming source/drain diffusion layers 7 and 8 using a thermal diffusion material 6. This is executed before the material 6 is removed.

[Function] In the present invention, during the plasma hydrogen treatment step, the electrode material components ejected from the electrode due to the collision of hydrogen ions are deposited on the thermal diffusion material 6; In the step of removing the heat diffusing material 6 that is performed after the above step, the heat diffusing material 6 can be completely removed by a lift-off method.

Therefore, the electrode material components can be efficiently and completely removed without damaging the device unlike when removing the electrode material components by performing sputter etching.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

First, as shown in FIG. 1, after preparing a quartz substrate 1,
An amorphous silicon film 2 is deposited on a quartz substrate 1 by performing low pressure CVD.

Next, a melt recrystallization method is performed to convert the amorphous silicon film 2 into a polycrystalline silicon film to form a polycrystalline silicon film 3, as shown in FIG.

Note that, without forming the amorphous silicon film 2, low pressure CV
The polycrystalline silicon film 3 may be formed from the beginning using D.

Next, as shown in FIG. 3, after patterning the polycrystalline silicon film 3 into a predetermined shape, a gate electrode 5 is formed via the gate oxide film 4, and then a coating containing silanol as a main component is applied to the entire surface. Apply mold diffusion material 6, perform thermal diffusion,
Source/drain diffusion layers 7 and 8 are formed on the polycrystalline silicon film 3.
form.

Next, plasma hydrogen treatment is performed using a predetermined parallel plate type plasma hydrogen treatment apparatus. In this way, as shown in FIG. 4, the electrode material component is deposited on the coating type diffusion material 6, and an electrode material component layer 9 is formed.

Next, the coating type diffusion material 6 is removed by etching using hydrofluoric acid (HF:H20=1:5). In this case, as shown in FIG. 5, the electrode material component layer 9 formed on the coating type diffusion material 6 is completely removed together with the coating type diffusion material 6 by the lift-off method.

Therefore, as shown in FIG. 6, the interlayer insulating film 10,
Contact holes 11 and 12, aluminum wiring layer 1
3 and 14 are formed sequentially. Here, a thin film transistor can be obtained.

As described above, in this example, after the source/drain diffusion layers 7 and 8 are formed using the coated diffusion material 6 and before the coated diffusion material 6 is removed, plasma hydrogen treatment is performed to reduce the electrode material components. is deposited on the coating type diffusion material 6,
Since this is removed at the same time as the coated diffusion material 6 is removed by etching, the electrode material component layer 9 formed by plasma hydrogen treatment can be completely removed.

Therefore, according to this embodiment, the electrode material component layer 9 can be efficiently removed without damaging the device unlike when removing the electrode material component by performing sputter etching, and leakage caused by the electrode material component can be removed. This has the effect of completely eliminating wire bonding defects and improving yield.

In addition, in the above-mentioned embodiment, the case was described in which the coating type diffusion material 6 was used as the heat diffusion material, but instead of this,
The heat diffusion material may be formed by CVD.

[Effects of the Invention] According to the present invention, the plasma hydrogen treatment step is performed after the formation of the source/drain diffusion layer using the thermal diffusion material and before the removal of the thermal diffusion material. By depositing the electrode material components that fly out of the electrode due to hydrogen ion collisions on the heat diffusion material, it is possible to completely remove them together with the heat diffusion material when the heat diffusion material is removed. It is possible to efficiently and completely remove the electrode material components without damaging the device as would be the case when performing this method.As a result, leaks and wire bonding defects caused by the electrode material components are completely eliminated. This has the effect of improving yield.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views showing an embodiment of the method for manufacturing a thin film transistor according to the present invention. 1... Quartz substrate 6... Coated diffusion material (thermal diffusion material) 7.8... Source/drain diffusion layer 9... Electrode material component layer Fig. 2 Fig. 3

Claims (1)

[Claims] In a method for manufacturing a thin film transistor having a plasma hydrogen treatment step, the plasma hydrogen treatment step is performed by using a heat diffusion material as a source.
A method for manufacturing a thin film transistor, characterized in that the process is performed after forming a drain diffusion layer and before removing the heat diffusion material.