KR101318197B1 - Electroplating system and electroplating method - Google Patents

Abstract

The electroplating apparatus of the present invention is a bath filled with a nonpolar solvent having a specific gravity higher than that of an electrolyte, and an electrolyte layer is formed on an upper surface of the nonpolar solvent, a copper electrode provided at a portion where the electrolyte layer of the tank is located, and the inside of the tank. An insulating substrate arranged to draw in and out of the furnace and having a seed electrode formed thereon; a driving unit for elevating the insulating substrate; and a power supply unit applying current between the copper electrode plate and the seed electrode. Can be formed uniformly and the grain size can be guaranteed.

Description

Electroplating Equipment and Electroplating Method {ELECTROPLATING SYSTEM AND ELECTROPLATING METHOD}

The present invention relates to an apparatus for forming a metal thin film on a substrate, and more particularly, to an electroplating apparatus and an electroplating method capable of uniformly forming a metal thin film on a large substrate.

In general, there are various metals such as aluminum (Al), molybdenum (Mo), and molybdenum-tungsten (MoW) as a gate electrode for forming a lower gate in a thin film transistor (hereinafter, referred to as TFT). The use of aluminum (Al), molybdenum (Mo), or the like as the gate electrode material is because, for example, an oxide film (Al ₂ O ₃ ) of aluminum (Al) can be used as the gate insulating film, thereby making it easy to manufacture the gate insulating film. to be.

However, recently, when a large display is implemented using aluminum or the like as a gate electrode material, the source is formed in a direction perpendicular to the gate line GL or the gate line which is interconnected with the gate electrode and is generally formed at the same time as the gate electrode. The resistance value of the data line DL connected to the region increases in proportion to the size of the display, and as a result, delay and distortion of the gate signal and the data signal occur.

In particular, in ultra-large flat panel displays where the length of one side is more than 1 meter, the low-resistance copper is indispensable because the wiring length increases exponentially. Among the wirings, the gate wirings of the TFTs are more difficult to lower the resistance than the data wirings, and therefore, particularly, the gates are required to be formed of a copper material.

Although copper (Cu) is a metal material having a lower resistance than aluminum and the like used as a conventional gate electrode material, an appropriate etching solution was not developed when etching a copper film to form a gate electrode and a gate line. In addition, there is a problem that the etching process of the copper film discharges heavy metals causing a lot of environmental pollution.

Unlike other metals described above, copper does not form fluoride or chloride, which may cause etching problems. In addition, copper may have a process time of 3 to 4 hours or more when stacked in a thick thickness to reduce resistance.

When copper is used as a gate electrode for large displays, copper wiring having a thickness of 2 micrometers or more is required to sufficiently reduce the resistance. In addition to the problem that it takes a long time to form a thick copper film, when the gate electrode structure having a thick film thickness is employed, a step coverage problem occurs when the gate insulating film is directly formed by a well-known process on the gate electrode. do.

To solve this problem, a 2 micron thick insulating film is deposited and patterned to form a trench structure. The trench structure is filled with copper by electrodeposition to form wiring, which requires special techniques to selectively electrodeposit copper in the trench. According to the conventional electrodeposition technique, in the case of a large area, resistance is not only possible to form a uniform copper film on the entire surface, but also a large apparatus for holding a liquid electrolyte is required.

Meanwhile, the prior art of manufacturing an array substrate using copper as a gate electrode is disclosed in Korean Patent Laid-Open No. 10-2006-115522.

The disclosed patent considers that the wiring temperature and the stress of the thin film transistor and the signal wiring such as the gate line and the data line to implement a flexible display device as compared to the case of using a glass substrate when manufacturing a thin film transistor. By using the electroless plating and electroplating method with low deposition temperature, signal wiring and thin film transistor are fabricated to prevent bending of the flexible substrate or cracking of signal line layers, and at the same time improve display quality.

To this end, the published patent forms a first electrode layer made of nickel or molybdenum, a second electrode layer made of copper, and first and second line layers for gate lines and data lines by electroless plating to form a seed layer for electroplating. After that, the source layer and the drain region, the third electrode layer for the gate line and the data line, and the third line layer are formed using the seed layer by an electroplating method.

However, the copper gate electrode and wiring forming method of the disclosed patent is formed on the entire surface of the substrate by the electroless plating method of the first electrode layer and the second electrode layer made of copper for strengthening the adhesion, the gate electrode and the wiring by the electroplating method And patterning the first and second electrode layers to form them. As a result, the published patent has the same problem as in the conventional etching of the copper electrode layer.

In addition, since the disclosed patent forms a gate electrode with a thick film of 1 micrometer or more, a step coverage problem may occur in a subsequent process, and no solution related thereto is disclosed.

Furthermore, when forming the source and drain regions in alignment with the gate electrode, since the mask for ion implantation blocking is formed on the upper portion of the gate electrode using a separate exposure mask and the ion implantation process is performed, it is 2-4 micrometers. The misalignment may occur, and such an error cannot be equally distributed to both ends of the channel region and thus is biased to one side, which causes a deterioration of the TFT's electrical performance.

Copper electroplating, on the other hand, does not have a problem with conventional methods when it is commonly used with older techniques. However, in the case of a large substrate having a side length of more than 2 meters, it is difficult to plate a metal film having a uniform thickness due to problems such as voltage drop.

In addition, the container itself containing the electrolyte solution must be large and the electrolyte solution also requires a huge amount of industrial problems.

Moreover, a problem that is greater than the uniformity of electrodeposited metal film thickness when plating is utilized in semiconductor processes is the control of grain size. For example, when the grains are coarsened, the surface of the electrodeposited metal film becomes rough. In the semiconductor process, the surface roughness of several microns may be a big problem, so the grain size should be less than the micron level unlike in general applications.

In general, the conventional wet copper plating, as shown in Figure 1, in the plating bath 100 filled with the CuSO ₄ electrolyte 110, the plate-shaped copper electrode (Cu electrode) 160, and the copper plating to be made The substrate 130 on which the metal electrode layer 150 is formed is immersed, the seed layer 150 is used as the cathode, and the copper electrode 160 is set as the anode to supply power from the power supply 140. When the electroplating process is performed, the copper plating layer 170 is formed on the metal seed layer.

On the other hand, using a conventional wet plating method of dipping a large area substrate having a large electrodeposition area in an electrolytic solution beyond 2 meters, such as a large display substrate for copper plating, as shown in Figure 2, ( -) In the metal seed layer 150 used as the electrode, a large difference in current density occurs between the portion (a) and the portion (b) close to the power supply 140 due to the voltage drop caused by the resistance.

In wet copper plating, electrodeposition rate is proportional to current density, and current density = (current / electrodeposition area) is established.

Therefore, since the portion of the high current density occurs quickly in Cu nucleation, the grain size is small as shown in (a) of FIG. 2, but the portion of the low current density does not occur in the nucleation. As shown, grain size increases.

Grain size depends on the voltage, current, electrolyte concentration, and distance between anodes in electroplating.

As a result, when copper plating is performed on a large-area substrate by a conventional immersion wet plating method, there is a problem in that grains of the resulting copper film cannot be formed in a uniform size.

KR 10-2006-115522 A

It is an object of the present invention to provide an electroplating apparatus and an electroplating method capable of uniformly forming the thickness of a metal thin film on a large substrate and ensuring grain size.

Another object of the present invention is to eliminate the pattern formation process of forming a metal wiring having a low resistance value in order to avoid signal delay or distortion in a large display device can be faster plating time and uniform thickness of the metal thin film It is to provide an electroplating apparatus and an electroplating method that can be.

The technical problem to be achieved by the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

Electroplating apparatus according to an embodiment of the present invention for solving the above problems is filled with a nonpolar solvent having a higher specific gravity than the electrolyte solution and the electrolyte layer is formed on the upper surface of the nonpolar solvent, and the electrolyte layer of the tank A copper electrode installed at a portion thereof, an insulating substrate arranged to draw in and out of the water tank, a seed electrode formed thereon, a driving unit for raising and lowering the insulating substrate, and a power supply for applying current between the copper electrode plate and the seed electrode It includes a supply.

The nonpolar solvent according to one embodiment is characterized in that the specific gravity is used chloroform (Chloroform) of specific gravity 1.5 g / ㎖.

Insulating substrate according to an embodiment is characterized in that the copper film is formed on the surface of the seed electrode when drawn into the tank.

In another embodiment, an electroplating apparatus is filled with a first nonpolar solvent having a higher specific gravity than an electrolyte and a second nonpolar solvent having a lower specific gravity than an electrolyte, and an electrolyte layer is formed between the first nonpolar solvent and the second nonpolar solvent. An insulating substrate having a water tank to be formed, a copper electrode provided at a portion where the electrolyte layer of the water tank is located, a seed electrode disposed to be movable up and down in the water tank, a driving unit for raising and lowering the insulation substrate, and the copper electrode and seed It includes a power supply for supplying a constant current between the electrodes.

According to another embodiment, chloroform is used as the first nonpolar solvent, and hexane is used as the second nonpolar solvent.

Insulating substrate according to another embodiment is characterized in that the copper film is formed on the surface of the seed electrode while being drawn from the inside of the tank to the outside of the tank.

Electroplating method according to an embodiment is filled with a non-polar solvent having a specific gravity higher than the electrolyte in the tank and forming an electrolyte layer on the upper surface of the non-polar solvent, and the insulating substrate on which the seed electrode is formed from the upper side of the tank into the tank at a constant speed And introducing a current into the seed electrode and the copper electrode to sequentially form a copper film on the surface of the seed electrode passing through the electrolyte layer.

The electroplating method according to another embodiment fills a water tank with a first nonpolar solvent having a higher specific gravity than an electrolyte and a second nonpolar solvent having a lower specific gravity than an electrolyte, and forms an electrolyte layer between the first nonpolar solvent and the second nonpolar solvent. And drawing out the insulating substrate on which the seed electrode is formed, from the inside to the outside of the water tank at a constant speed, and applying a current to the seed electrode and the copper electrode to sequentially form a copper film on the surface of the seed electrode passing through the electrolyte layer. It includes a step.

In the electroplating apparatus and the plating method according to the present invention configured as described above, by forming a thin electrolyte layer in the tank, and then elevating the insulating substrate in the tank to form a copper film sequentially on the seed electrode, a metal thin film on a large substrate The thickness of can be formed uniformly and the grain size can be ensured.

In addition, by sequentially forming a copper film on a large substrate, a pattern forming process for forming a metal wiring having a low resistance value is unnecessary in order to prevent signal delay or distortion in a large display device, so that plating time can be accelerated and metal The thickness of the thin film can be made uniform.

1 is a block diagram of a wet copper plating apparatus according to the prior art.
2 is a view showing that the grain size generated according to the region is different when forming a thin copper film on a large substrate using a wet copper plating apparatus according to the prior art.
3 is a block diagram of an electroplating apparatus according to an embodiment of the present invention.
4 is a block diagram of an electroplating apparatus according to another embodiment of the present invention.
5 is a plan view illustrating an array substrate of a liquid crystal display according to the present invention.
6 to 21 are cross-sectional views illustrating a process of manufacturing a trench-shaped copper bottom gate thin film transistor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The sizes and shapes of the components shown in the drawings may be exaggerated for clarity and convenience. In addition, terms defined in consideration of the configuration and operation of the present invention may be changed according to the intention or custom of the user, the operator. Definitions of these terms should be based on the content of this specification.

3 is a block diagram of an electroplating apparatus according to an embodiment of the present invention.

The electroplating apparatus according to an embodiment includes a water tank 50 in which a nonpolar solvent 52 having a higher specific gravity than the electrolyte solution is filled, and an electrolyte layer 54 is formed on an upper surface of the nonpolar solvent 52. An insulating substrate 11 having a copper electrode 56 provided at an inner upper end, a seed electrode 12 disposed in the tank 50 so as to be movable upward and downward and inserted into the tank 50, and an insulating substrate ( A driver 64 for elevating and elevating 11, and a power supply 62 for supplying a constant current between the copper electrode 56 and the seed electrode 12.

The water tank 50 has a height at which the top surface is opened and the entire insulation substrate 11 can be inserted so that the insulation substrate 11 can be inserted and withdrawn in the vertical direction. In addition, since the width of the water tank 50 may be a width through which the substrate 11 can be inserted, the width of the water tank 50 is narrowed to prevent waste of the electrolyte solution or the nonpolar solvent 52.

As the nonpolar solvent 52, a solvent having a specific gravity higher than that of the electrolyte solution and not mixed with the electrolyte solution may be used so that the electrolyte layer 54 may be disposed on the top surface of the nonpolar solvent 52.

The electrolyte solution may be an aqueous copper sulfate solution, the nonpolar solvent 52 has a specific gravity of 1.5 g / ㎖, chloroform (Chloroform) is a non-flammable, transparent and fluid high density liquid is preferably used.

Therefore, the non-polar solvent 52 is filled in the water tank 50, and the electrolyte layer 54 is formed in the upper surface of this non-polar solvent 52. As shown in FIG. Since the thickness of the electrolyte layer 54 is electrodeposited only at the portion where the electrolyte layer 54 is present during electroplating, the thickness of the electrolyte layer 54 can be adjusted to control the length of the copper film electrodeposited at the time of electroplating. .

The thickness of the electrolyte layer 54 is set to a thickness that allows the copper film to be electrodeposited to a large thickness through various experiments.

As the method for forming the seed electrode 12 on the insulating substrate 11, sputtering or a thin film deposition method may be used. A method of forming the seed electrode 12 on the insulating substrate 11 will be described in detail below.

The copper electrode 56 is mounted on the upper end of the inner surface of the water tank 50, that is, the portion where the electrolyte layer 54 is located and is in contact with the electrolyte layer 54.

The power supply 62 serves to supply a constant current between the seed electrode 12 and the copper electrode 56 and is turned on / off in response to a signal applied from a control unit or a manipulation panel directly operated by a user.

The driving unit 64 is to elevate the insulating substrate 11 in the up and down direction, and includes a solenoid structure that is operated when power is applied, a driving motor and a screw bar, and a structure in which the screw bar is rotated to raise and lower the insulating substrate when the driving motor is driven. Any drive unit can be applied as long as it can lift and lower the insulating substrate 11 such as a power cylinder structure.

Thus, the operation of the electroplating apparatus according to an embodiment of the present invention configured will be described below.

The insulating substrate 11 on which the seed electrode 12 is formed is disposed on the upper surface of the water tank 50. At this time, the non-polar solvent 52 is filled in the water tank 50, and the electrolyte layer 54 is formed on the upper surface of the non-polar solvent 52.

In this state, when the driving unit 64 is operated, the insulating substrate 11 descends and is inserted into the water tank 50 to be in contact with the electrolyte layer 54 and the copper electrode 56 and the seed electrode 12 in the power supply unit 62. When a current is applied between the electrodes, a copper film is formed on the surface of the seed electrode 12 locally only at the portion where the electrolyte layer 54 is present. That is, when a current is applied between the seed electrode 12 and the copper electrode 56 in the power supply 62, metal ions of the copper electrode 56 are electrodeposited on the surface of the seed electrode 12 through the electrolyte layer 54. A copper film is formed.

Then, the insulating substrate 11 is lowered at a constant speed so that a copper film having a uniform thickness is formed on the surface of the seed electrode 12 of the entire insulating substrate 11.

As such, the electroplating apparatus according to the exemplary embodiment plays the same role as forming the copper film on the small substrate because the copper film is locally formed only at the portion in which the electrolyte layer 54 is provided. The thickness can be formed uniformly.

Performing such a copper plating while moving the insulating substrate in the downward direction can produce a relatively uniform copper grain (Cu grain) of 2000-3000 kPa on a large-area substrate, and at this time, electroplating 2000 The copper film having a thickness of ˜3000 kV can also lower the resistance of the metal electrode, which is the cathode.

When the thickness of the copper film is increased, the insulating substrate is repeatedly lowered into the water bath to electrodeposit the copper film.

In addition, in the present invention, the falling speed and the current density of the insulating substrate may have a great influence on the copper electrodeposition rate, the copper grain size, and the electrodeposition shape. When the current density is higher than a certain value, electrodeposition is performed in the form of a dendrite, and electrodeposition is performed in the form of a dendrite even when the falling speed of the insulating substrate is below a specific value.

In addition, if the falling speed of the insulating substrate is too slow, the electrodeposited copper film becomes thick and the resistance of the metal electrode is lowered, which results in an instantaneous increase in current density. Therefore, in the present invention, a uniform film is obtained by performing at a current density and a falling speed at which no dendrite growth occurs. To do this, first scan at a high current density to nucleate, and then repeat the descent of the insulating substrate at low current densities so that copper can be filled in the trench while avoiding dendrite.

In addition, if the current density is below a certain value or the falling speed is too fast, nucleation is difficult, resulting in large grain size and roughening of the copper film surface.

In the present invention, all metals and alloys including copper may be used as the electrodeposition metal.

It is also possible to form a thin copper thin film in this manner, and then immerse the entire insulating substrate in the electrolytic solution to perform electroplating to fill a uniform copper film, trench or hole.

4 is a block diagram of an electroplating apparatus according to another embodiment of the present invention.

Referring to FIG. 4, the electroplating apparatus according to another embodiment is filled with a first nonpolar solvent 70 having a higher specific gravity than an electrolyte and a second nonpolar solvent 72 having a lower specific gravity than an electrolyte, and the first nonpolar solvent ( The tank 50 in which the electrolyte layer 54 is formed between the 70 and the second nonpolar solvent 72, the copper electrode 56 provided at the upper end of the tank 50, and the tank 50 in the vertical direction. An insulating substrate 11 having a seed electrode 12 having a copper film formed thereon while being movably disposed therefrom and drawn out of the tank 50 to the outside of the tank 50, and a driving unit 64 for elevating the insulating substrate 11; And a power supply 62 for supplying a constant current between the copper electrode 56 and the seed electrode 12.

The water tank 50 has a height at which the top surface is opened and the entire insulation substrate 11 can be inserted so that the insulation substrate 11 can be inserted and withdrawn in the vertical direction. In addition, since the width of the water tank 50 may be a width through which the substrate 11 can be inserted, the width of the water tank 50 is narrowed to prevent waste of the electrolyte solution and the nonpolar solvent.

As the first nonpolar solvent 70, a solvent having a specific gravity higher than that of the electrolyte solution and not mixed with the electrolyte solution may be used so that the electrolyte solution may be disposed on the upper surface of the first nonpolar solvent 70.

As the second nonpolar solvent 72, a specific gravity is lower than that of the electrolyte so that the electrolyte is disposed on the lower surface of the second nonpolar solvent 72, and a solvent that does not mix with the electrolyte is used.

Therefore, an electrolyte layer 54 having a predetermined thickness is formed between the first nonpolar solvent 70 and the second nonpolar solvent 72.

Copper electrolyte solution may be used as the electrolyte, the first nonpolar solvent may be used chloroform (Chloroform) having a specific gravity of 1 or more, the second nonpolar solvent may be used hexane (Hexane) with a specific gravity of 1 or less.

According to the copper plating apparatus according to another exemplary embodiment, when the driving unit 64 pulls the insulating substrate 11 out of the water tank 50 in the upward direction, the copper plating apparatus is connected to the seed electrode 12 of the insulating substrate 11. A copper film is formed.

Looking at the operation of the copper plating apparatus according to another embodiment, the insulating substrate 11 on which the seed electrode 12 is formed is disposed in the water tank 50. In this case, an electrolyte layer 54 is formed between the first nonpolar solvent 70 and the second nonpolar solvent 72 in the water tank 50.

When the driving unit 64 is operated in this state, the insulating substrate 11 is drawn out at a constant speed from the inside of the water tank 50 to the outside of the water tank 50. When a current is applied between the copper electrode 56 and the seed electrode 12 in the power supply 62, a copper film is formed on the surface of the seed electrode 12 locally only at the portion where the electrolyte layer 54 is present.

That is, when a current is applied between the seed electrode 12 and the copper electrode 56 in the power supply 62, metal ions of the copper electrode 56 are electrodeposited on the surface of the seed electrode 12 through the electrolyte layer 54. A copper film is formed.

When the insulating substrate 11 rises at a constant speed and is completely drawn out of the water tank 50, a copper film having a uniform thickness is formed on the entire surface of the seed electrode 12 of the insulating substrate 11.

As such, the electroplating apparatus according to another embodiment may play the same role as forming the copper film on the small substrate because the copper film is locally formed only at the portion where the electrolyte layer 54 is present. The thickness can be formed uniformly.

5 is a plan view illustrating an array substrate of a liquid crystal display according to the present invention.

The liquid crystal display device includes an array substrate, a color filter substrate, and a liquid crystal layer formed between the array substrate and the color filter substrate to display an image.

Referring to FIG. 5, the array substrate includes a plurality of gate lines GL extending in a first direction D1 and a plurality of data lines extending in a second direction D2 perpendicular to the first direction D1. DL). A plurality of pixel regions (pixel electrodes) are formed by a gate line GL simultaneously formed with the plurality of gate electrodes 14 or a plurality of data lines DL formed in a direction perpendicular to the gate line and connected to the source electrode S. (23) is defined.

The array substrate also includes a gate electrode 14 branched from the gate line GL, a source electrode S branched from the data line DL, and a drain electrode D electrically connected to the pixel electrode 23. And a thin film transistor (TFT).

A manufacturing process of a thin film transistor according to an exemplary embodiment of the present invention included in such an array substrate will be described with reference to FIGS. 6 to 21.

As shown in FIG. 6, a first adhesive layer 120a formed of a conductor, for example, Ni, MoW, or AL, on a transparent insulating substrate 11, for example, a glass substrate by sputtering or thin film deposition, and The base metal film 120 formed of the first electrode layer 120b is formed.

Here, for example, the first adhesive layer 120a is formed of 500 mW using Ni, and the first electrode layer 120b is formed of 2000 mW using MoW, for example.

Subsequently, although not shown, after forming the photoresist, the base metal layer is patterned using a gate mask to form a seed electrode 12 corresponding to the gate electrode having a shape as shown in FIG. 7.

When the pattern formation of the seed electrode 12 is completed in this way, for example, an insulating film 13 having a thickness of 1.5 micrometers is deposited as shown in FIG. 8 by PECVD (Plasma Enhanced Chemical Vapor Deposition) using silicon oxide or silicon nitride. .

Thereafter, the photoresist layer 15 is coated on the insulating layer 13 as shown in FIG. 9, and then back exposure is performed. Then, when the photoresist layer 15 of the negative type that is not exposed by the seed electrode 12 is removed after exposure and development without a mask by the back exposure, self alignment is performed as shown in FIG. 10 to correspond to the gate pattern. Groove pattern is formed. In this case, if the insulating mask 13 corresponding to the recess corresponding to the gate pattern is used using the remaining etching mask 15a, for example, reactive ion etching using hydrogen fluoride (HF) may be performed. As described above, the trench guide portion 16 is formed on the insulating substrate 11 to form a trench contact window in which the seed electrode 12 is exposed upward. Thereafter, the etching mask 15a is removed.

Thereafter, when the electrode is selectively electrodeposited to a thickness of 1 to 2 micrometers by electroplating on the exposed seed electrode 12 using the trench guide portion 16, copper is formed in the trench guide portion 16. Copper is electroplated only on the upper trenches of the seed electrode 12 exposed without being electrodeposited to selectively form a copper film 37 serving as a gate electrode. That is, when the seed electrode 12 is used as the cathode and the copper metal is set as the anode, the electroplating process is performed to selectively form the copper film 37.

In the present invention, as a copper plating process for forming a copper film 37 which is a copper gate electrode, a copper film is formed by a scanning method by the electroplating apparatus shown in FIGS. 3 and 4.

When the thickness of the copper film is thinner than the set thickness, the copper gate electrode 14 is formed by immersing the substrate in the electrolyte bath and performing electroplating once again.

As shown in FIG. 12, in order to planarize the copper gate electrode 14, considering that the copper gate electrode 14 is formed on the upper portion of the trench guide portion 16, the CMP (Chemo-Mechanical) A planarization process such as polishing or grinding is performed to planarize the gate electrode 14, that is, the copper wiring and the trench guide portion 16.

In this case, it is necessary to planarize the overcharged copper gate by moving the polishing apparatus in a random direction on the large-area substrate, and planarize the overcharged copper gate by polishing only with a fine abrasive without a copper etching solution.

In this case, it is preferable to simultaneously form the gate line wiring connected to the gate electrode 14 to apply a gate signal to the TFT. In this case, the data line DL connected to the source electrode S may also be formed of the same process / material as that of the gate line GL.

Thereafter, as illustrated in FIG. 13, the gate insulating layer 17 is deposited to a thickness of 1000 占 by, for example, PECVD on the upper portion of the gate electrode 14 and the trench guide portion 16. The gate insulating layer 17 may use a silicon oxide film or a silicon nitride film.

Thereafter, as shown in Fig. 14, an amorphous silicon layer 18 is deposited on the gate insulating film 17 by, for example, CVD. In-situ doping may be simultaneously performed to form the source and drain regions when the amorphous silicon layer 18 is deposited.

In the case of configuring the polycrystalline silicon TFT, in-situ doping is generally not performed as described later. In the case of crystallization using a laser, a crystallization process treatment is performed before and after the protective oxide film. In the case of using a non-laser method, the method may be different depending on the method. In this embodiment, a method of using MILC for crystallization of amorphous silicon will be described as an example.

When the amorphous silicon layer 18 is deposited, a photoresist mask 19 for forming a metal induction film for inducing the crystallization of the amorphous silicon layer 18 in a lift-off manner is formed as shown in FIG. 15. do. A nickel pattern layer 20, which is a metal induction side crystallization (MILC) metal induction film, is formed on the photoresist mask 19 as shown in FIG. 16. In this case, in addition to nickel, Pd, Ti, Ag, Au, Al, Sn, Sb, Cu, Co, Cr, Mo, Tr, Ru, Rh, Cd, Pt, etc. are mainly used as the material used as the crystallized metal induction film. do.

After the nickel pattern layer 20 is formed, the amorphous silicon layer 18 is crystallized by MILC (metal induced side crystallization) low temperature heat treatment, and then the nickel pattern layer 20 is removed to form the crystallized silicon layer 18a. It is formed as follows.

Here, the technique for metal-induced side crystallization of amorphous silicon by MILC heat treatment is disclosed in Korean Patent Laid-Open Publication No. 10-2009-42122 filed by the inventor of the present invention, a detailed description thereof will be omitted.

After the MILC heat treatment is performed to complete the crystallization of the amorphous silicon to form the polycrystalline silicon layer 18a, the protective oxide film 21 is deposited on the polycrystalline silicon layer 18a to have a thickness of 3000 m 3 as shown in FIG. Further, a photoresist is applied over the protective oxide film 21 to form a photoresist layer 22 as shown in FIG.

Subsequently, as shown in FIG. 19, the etching mask (not shown) left by removing the positive photoresist layer 22 exposed after developing and exposing without a mask by back exposure is removed. When the protective oxide film 21 is etched, the ion implantation blocking mask 21a is formed as shown in FIG.

A source region and a drain region are formed by ion mass doping (IMD) using the ion implantation blocking mask 21a, and the dopant implanted by heat treatment is activated.

Referring to FIG. 21, an etching mask (not shown) is formed on the activated source electrode S and the drain electrode D, and the channel layer C is formed by etching, and then an inorganic insulating layer is formed thereon. A photoresist layer 22 is formed. Thereafter, a contact hole for exposing the drain electrode D is formed through the photoresist layer 22, and the pixel electrode 23 made of ITO or IZO is formed on the photoresist layer 22. Is done.

In the above-described embodiment, the gate line is formed of the same process / material when the gate electrode is formed, but the data line connected to the source electrode may be formed of the same process / material as the gate line.

The copper lower gate thin film transistor manufacturing process as described above may be applied to other crystallization methods in addition to the above-described MILC on a substrate on which planarized thick gate copper wiring is formed, and may be partially modified to other TFT manufacturing processes.

As described above, the present invention can form a copper having a low resistance value suitable for a large display to a thickness usable as the lower gate by electroplating, and eliminate the step coverage through the planarization process used as the gate electrode. Can be.

In addition, since the present invention uses copper as the gate electrode, the source and drain can be automatically aligned to the gate by the back exposure without a separate mask, thereby minimizing the alignment error.

In the above embodiment, although polycrystalline silicon is used as the activation region, it is also possible to use amorphous silicon as the activation region.

However, in this case, instead of forming the mask for ion implantation blocking using the back exposure, it is required to form the mask by the known method as in the prior art.

The present invention is applicable to thin film transistors and wirings used in display devices such as active liquid crystal displays (AMLCDs) and organic light emitting diodes (AMOLEDs).

11: insulating substrate 12: seed electrode
13: insulating film 14 gate electrode
15: photoresist layer 16: trench type guide part
17: gate insulating film 18: amorphous silicon layer
18a: polycrystalline silicon layer 19: photoresist mask
20: nickel pattern layer 21: protective oxide film
21a: ion implantation blocking mask 22: photoresist layer
50: water tank 54: electrolyte solution layer
56: copper electrode 62: power supply

Claims (8)

A bath in which a nonpolar solvent having a specific gravity higher than that of the electrolyte is filled and an electrolyte layer is formed on an upper surface of the nonpolar solvent;
A copper electrode provided at a portion of the tank with an electrolyte layer;
A driving unit configured to lift and lower the insulating substrate having a seed electrode formed therein and drawn into the tank; And
Electroplating apparatus including a power supply for applying a current between the copper electrode and the seed electrode. The method of claim 1,
The nonpolar solvent is an electroplating apparatus, characterized in that chloroform having a specific gravity of 1.5 g / ml is used. The method of claim 1,
Electroplating apparatus, characterized in that the copper film is formed on the surface of the seed electrode when the insulating substrate is drawn into the tank. A water tank in which a first nonpolar solvent having a specific gravity higher than that of the electrolyte and a second nonpolar solvent having a low specific gravity compared to the electrolyte are filled, and an electrolyte layer is formed between the first nonpolar solvent and the second nonpolar solvent;
A copper electrode provided at a portion where the electrolyte layer of the tank is located;
A driving unit for elevating an insulating substrate having a seed electrode disposed to be elevated in the tank; And
Electroplating apparatus including a power supply for supplying a constant current between the copper electrode and the seed electrode. 5. The method of claim 4,
The first nonpolar solvent is chloroform (Chloroform) is used, the second nonpolar solvent is electroplating apparatus, characterized in that hexane (Hexane) is used. 5. The method of claim 4,
Electroplating apparatus, characterized in that the copper substrate is formed on the surface of the seed electrode while the insulating substrate is drawn out of the tank from the inside of the tank. Filling the tank with a nonpolar solvent having a higher specific gravity than the electrolyte and forming an electrolyte layer on the upper surface of the nonpolar solvent;
Installing a copper electrode at a portion where the electrolyte layer of the tank is located;
Drawing an insulating substrate on which a seed electrode is formed, into the tank from the upper side of the tank at a constant speed;
Applying a current to the seed electrode and the copper electrode to sequentially form a copper film on the surface of the seed electrode passing through the electrolyte layer. Filling a water tank with a first nonpolar solvent having a higher specific gravity than the electrolyte and a second nonpolar solvent having a lower specific gravity than the electrolyte, and forming an electrolyte layer between the first nonpolar solvent and the second nonpolar solvent;
Installing a copper electrode at a portion where the electrolyte layer of the tank is located;
Drawing an insulating substrate on which a seed electrode is formed, from the inside to the outside of the water tank at a constant speed;
Applying a current to the seed electrode and the copper electrode to sequentially form a copper film on the surface of the seed electrode passing through the electrolyte layer.

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