Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2001-11-02
2004-03-16
Whitehead, Jr., Carl (Department: 2813)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S674000, C438S678000, C438S627000, C438S628000, C205S157000, C205S123000
Reexamination Certificate
active
06706628
ABSTRACT:
This application claims the benefit of Korean Patent Application No. 2000-67200 filed on Nov. 13, 2000, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for forming a thin film, and more particularly, to a method for forming a thin film and a method for fabricating a liquid crystal display device using the same, in which a process is simplified and uniform thin film characteristic can be obtained.
2. Discussion of the Related Art
Traditionally, an aluminum or its alloy has been used as a line material of a semiconductor device or a liquid crystal display device. Recently, there has been an increase in the use of copper having excellent electric conductivity as the line material in semiconductor device and liquid crystal display devices instead of aluminum.
A related art method for forming a copper thin film uses either a Plasma Vapor Deposition (PVD) method based on sputtering or a Chemical Vapor Deposition (CVD) method regardless of whether the semiconductor or liquid crystal display device has a glass substrate or a silicon substrate. These methods have a problem in that a wet chemical process is required, and therefore additional complicated processes, such as removing, washing, and drying, are required.
A related art method for forming a copper thin film will be described with reference to the accompanying drawings.
FIGS. 1
a
to
1
d
are sectional views illustrating a related art method for forming a copper thin film.
As shown in
FIG. 1
a
, a barrier layer
12
is formed on a substrate
11
, and a first metal layer
13
, an insulating layer
14
and a dielectric layer
15
are sequentially deposited on the barrier layer
12
. A silicon substrate is used for a semiconductor device or a glass substrate is used for a liquid crystal display device.
A photoresist is deposited on the dielectric layer
15
and then patterned by exposure and developing processes. Thus, a photoresist pattern
16
is formed to selectively expose a surface of the dielectric layer
15
.
Subsequently, as shown in
FIG. 1
b
, the dielectric layer
15
is selectively removed by an etching process using the photoresist pattern
16
as a mask to partially expose a surface of the insulating layer
14
. Then, O
2
plasma process is performed in such a manner that O
2
gas is permeated into the insulating layer
14
to react with the first metal layer
13
. As a result, a metal oxide
17
is formed.
Afterwards, as shown in
FIG. 1
c
, the substrate
11
is loaded into etching equipment, and beta-diketone vapor is implanted into the substrate
11
under the ambient temperature of 100 ~450° C. to remove the metal oxide
17
.
Finally, after the substrate
11
is loaded into the CVD equipment, a second metal layer
19
is formed. Thus, the related art process for forming a thin film is completed.
At this time, the substrate
11
is loaded into the CVD equipment after additional processes, such as washing, rinsing, and drying, are performed. This complicates the whole process.
The first metal layer
13
and the second metal layer
19
are formed of copper which will be expected to substitute for aluminum as a line material of a semiconductor device or a liquid crystal display device.
However, the related art method for forming a thin film has several problems.
First, in case the metal, specifically copper, is formed by the CVD process, resistivity of a copper film increases and foreign substances may contaminate the copper film during the process steps. Also, surface uniformity is too poor to control following process steps.
Furthermore, although an oxide film is etched in the etching equipment, a new oxide film grows during loading from the etching equipment into deposition equipment, which is separate from the etching equipment. A number of processes such as washing, rinsing and drying are required to remove the oxide film. For this reason, the number of steps in the whole process increases. This could lead to increased processing time and production cost.
SUMMARY OF THE INVENTION
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
Another object of the present invention is to provide a method for forming a thin film and a method for fabricating a liquid crystal display device using the same, in which a process is simplified and surface uniformity of a thin film is improved to obtain a process margin.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method for forming a thin film according to the present invention includes the steps of forming a diffusion barrier film on a substrate, forming a metal seed layer on the diffusion barrier film, removing a metal oxide film formed on a surface of the metal seed layer using an electric plating method, and depositing metal on the metal seed layer, in which the metal oxide film is removed, using the electric plating method.
In another aspect, a method for fabricating a liquid crystal display device according to the present invention includes the steps of forming a first metal seed layer on a glass substrate, depositing a first metal layer using an electric plating method, patterning the first metal seed layer and the first metal layer to form a gate line and a gate electrode, forming a gate insulating film on an entire surface including the gate line, forming a semiconductor layer on the gate electrode, forming a second metal seed layer on the entire surface including the semiconductor layer, depositing a second metal layer using the electric plating method, patterning the second metal seed layer and the second metal layer to form a data line crossing the gate line and source/drain electrodes on the semiconductor layer, and forming a pixel electrode connected with the drain electrode, on a passivation film formed on the entire surface including the data line.
The method for forming a thin film according to the present invention is characterized in that washing and deposition processes are performed by one piece of equipment to reduce the number of process steps, and potential and pH are properly controlled to grow copper, thereby obtaining a copper thin film having excellent film characteristic. At this time, copper deposition is performed under low pH and negative potential using an electric plating method.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 6297441 (2001-10-01), Macris
patent: 6403481 (2002-06-01), Matsuda et al.
patent: 2002/0000382 (2002-01-01), Morriss et al.
patent: 1005078 (2000-05-01), None
Bae Jong Uk
Kim Jae Jeong
Kim Soo Kil
Jr. Carl Whitehead
LG. Philips LCD Co. Ltd.
McKenna Long & Aldridge LLP
Pham Thanhha
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