KR100747511B1 - TFT Display Panel Manufacturing Method - Google Patents

Abstract

In the present invention, in the method of manufacturing a polycrystalline thin film transistor display substrate through crystallization using a metal, the metal particles having an appropriate distribution density so that the electrical properties of the thin film transistor is prevented by the metal particles for forming a crystallization nucleus in the amorphous silicon layer Provided is a method of manufacturing a polycrystalline thin film transistor display substrate on which a metal layer on which is disposed is formed.

The present invention for this purpose is to heat the glass substrate to the reaction temperature for the chemical adsorption, the metal molecule adsorption step of chemically adsorbing the metal molecules on the glass substrate on which amorphous silicon is formed by introducing a source gas containing the metal into the process space: A metal molecule having a uniform distribution by adsorption is disposed on the amorphous silicon layer on the glass substrate, and a plurality of amorphous silicon particles are included in the planar boundary region occupied by the metal molecule. Purging and removing excess molecules that are not chemisorbed and forming a metal distribution region in which a group of silicon particles per metal element are disposed: The glass substrate is heated to a thermal decomposition temperature or pyrolysis is performed while the metal molecules are disposed. The reaction gas is introduced into the process space at a temperature not generated to Acquiring only the metal element takes place in a distribution area includes a metal layer formation step of obtaining a metal layer having a low-concentration uniformly distributed.

Description

Polycrystalline thin film transistor flat panel display manufacturing method {TFT Display Panel Manufacturing Method}

1 is a conceptual diagram showing an ALD (Atomic Layer Deposition) application device applied to form a metal layer according to the present invention,

2 is a conceptual diagram showing that the nickel molecules are chemisorbed while having a predetermined occupation area on the amorphous silicon layer,

3 is a side conceptual view illustrating a step of forming a metal layer according to the present invention.

 The present invention provides a method for manufacturing a polycrystalline thin film transistor display substrate through crystallization using a metal, the metal particle having an appropriate distribution density so that the electrical properties of the thin film transistor are prevented from being deteriorated by the metal particles for forming a crystallization nucleus in an amorphous silicon layer. The present invention relates to a method for manufacturing a polycrystalline thin film transistor array substrate on which a metal layer on which is disposed is formed.

As is well known, the flat panel display device most widely used as a display device is, for example, a liquid crystal display (LCD) device using liquid crystal.

Unlike CRTs, these LCDs do not have self-luminous properties and require backlighting. However, they are low power consumption due to their low operating voltage, and are widely used flat panel displays because they can be used in terms of weight and volume.

The LCD uses a color filter to express colors. The pixel unit of the filter is composed of three subpixels of RGB, and a matrix control method is adopted to express colors through these individual cells.

Among them, an active matrix LCD uses three transistors capable of processing red, green, and blue signals for each pixel to obtain vivid colors, and a TFT (Thin Film Transister) LCD is typical.

For this reason, the LCD manufacturing process is in the same category as that of the semiconductor manufacturing process, so as to form a thin film and an electrode pattern of, for example, indium tin oxide (ITO) on the surface of the LCD substrate as in the case of the semiconductor manufacturing process, as in the case of the semiconductor manufacturing process. photo lithography is being used.

On the other hand, unlike wafers, the fundamental reason for using glass as a substrate is different from that of a semiconductor manufacturing process.

In more detail, the deposition by thermal decomposition of silicon gas (SiH4) for forming a silicon film on the substrate requires a high temperature of 600 ℃ or more, the glass substrate is a deformation occurs at 450 ℃ ~ 500 ℃, semiconductor manufacturing process Cannot be directly applied.

Accordingly, plasma deposition (PECVD: Plasma Enhanced Chemical Vapol Deposition) is generally performed, which can deposit silicon at a temperature within 350 ° C., thereby enabling the use of a glass substrate.

However, the silicon thin film formed at this time is limited to amorphous silicon (armophous-silicon), which drives the pixel using an amorphous silicon thin film transistor in the matrix control method, and the driving circuit constitutes a circuit in a single crystal silicon wafer. To connect separately.

In other words, amorphous silicon has low electron mobility and cannot be used in high-speed operation circuits. LCDs using amorphous silicon TFTs form pixel transistors on a substrate and use a tape carrier package (IC) driver around the substrate. The glass substrate and PCB must be connected.

In this case, there is a problem in that the driving IC and the mounting cost increase, and the connection part between the TCP driver IC and the PCB or the connection part between the TCP driver IC and the glass substrate is vulnerable to mechanical and thermal shock and the contact resistance is increased. As the resolution becomes higher, the pad pitch of the signal line and the scan line becomes shorter, which makes the TCP bonding itself difficult.

As a result, in view of the trend of flat panel display devices having a large size and high image quality, amorphous silicon TFTs are slow in size and large in size, and thus have limitations in satisfying these requirements.

Accordingly, the key is to convert the amorphous silicon formed on the glass substrate into crystalline silicon, and the performing methods include solid state crystallization (SPC), laser crystallization (ELC), metal induction crystallization (MIC), and metal induced side crystallization (MILC). ) There is a way.

Among them, the current attention in productivity and large area of the substrate is that a specific type of metal layer such as metal induction crystallization or metal induction side crystallization is deposited or added to amorphous silicon, and then heat treated to amorphous glass at low temperatures where the glass substrate is not damaged. To crystallize silicon.

At this time, the crystal nuclei, which are the metal particles themselves, are referred to as MIC, and the boundary of silicon crystallized by the MIC acts as a new crystal nucleus so that crystallization of silicon proceeds to the side.

However, in the polycrystalline thin film transistor by the metal induction crystallization or the metal induction side crystallization, it is confirmed that a large amount of metal diffused in the channel region is actually distributed, and thus the metal contamination problem is also serious.

That is, the contamination of the metal impurities in the channel region has a great influence on the leakage current generation, thereby reducing the field effect mobility and the threshold voltage characteristics, and thus the electrical characteristics of the polycrystalline silicon thin film transistor.

As a result, in a situation where high temperature heat treatment is not possible due to the physical properties of the glass substrate and low temperature heat treatment cannot be performed, formation of a metal catalyst layer for performing low temperature heat treatment is inevitable, and the input catalyst metal has a dilemma acting as a contaminant in the channel region. I was in trouble.

In order to improve this, for example, it is proposed to prevent a metal material from penetrating into the channel region by providing a separate region surrounding the channel region by an offset (Patent Application No. 1998-0003781, name). : Thin film transistor manufacturing method).

However, in order to leave such an offset region, a process of separately forming an offset pattern is added. The main part of the thin film transistor is the formation of a pattern, and the decrease in productivity is inevitable due to the addition of a process that is a redundant formation of such a pattern. More fundamental solutions are needed.

Another problem is that the formation of the metal catalyst layer by sputtering has a problem in that it cannot cope with a large display area, especially when nickel is targeted.

In other words, sputtering is used in which a target nickel panel is disposed in a process space, a plasma is formed between the substrates, and the nickel particles decomposed into the substrate are adsorbed.

To this end, argon gas is introduced into the process space (vacuum), and nickel particles are adsorbed onto the substrate by the electromagnetic field. Since the nickel itself is ferromagnetic, it is difficult to form a magnetic field inside the process space.

In order to improve this, the magnetic field of the target (nickel) is arranged vertically so that a magnetic field is formed in the process space, but such a target is formed to have a side length exceeding about 300 mm. It is known to be difficult.

Therefore, in a large-area display substrate, it is required that an alternative method of sputtering be applied in forming the metal layer.

Accordingly, the present invention has been made to improve the above problems, by forming a metal layer to maintain a proper distribution of metal particles for forming a crystallization nucleus in the amorphous silicon layer, to have a uniform distribution while having a low concentration of metal particle distribution It is an object of the present invention to provide a polycrystalline thin film transistor display substrate manufacturing process in which a metal layer is formed on a glass substrate, thereby increasing the crystallization rate of amorphous silicon and reducing the crystallization temperature by the metal, thereby substantially reducing contamination by metal particles.

In the present invention, in the formation of a metal layer, a metal compound molecule (gas) having a relatively large size is introduced into a process space having a temperature at which pyrolysis does not occur, thereby chemically adsorbing a glass substrate, and thereby a metal having a uniform distribution. While the molecules are disposed on the amorphous silicon layer on the glass substrate, a number of amorphous silicon particles are included in the planar boundary region occupied by the metal molecules, thereby removing other containing atoms other than the metal atoms from the metal molecules. Only one metal particle is arranged in a clustered area of a plurality of silicon particles, which are planar regions occupied by the metal molecules.

Thereby, a metal layer can be obtained as an ultra-thin film which is uniform and low concentration.

DETAILED DESCRIPTION Hereinafter, the most preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. . Other objects, features, and operational advantages, including the purpose, working effects, and the like of the present invention will become more apparent from the description of the preferred embodiment.

For reference, the embodiments disclosed herein are only presented by selecting the most preferred examples to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, Various changes, modifications, and other equivalent embodiments may be made without departing from the spirit of the present invention.

Exemplary Drawing FIG. 1 is a conceptual view showing an ALD (Atomic Layer Deposition) apparatus applied to form a metal layer thinner than a single atomic layer on a glass substrate according to the present invention. Figure 3 is a conceptual view showing a chemisorbed while having an occupied area, Figure 3 is a side conceptual view showing a step of forming a metal layer according to the present invention.

The present invention provides a method for manufacturing a polycrystalline thin film transistor display substrate by depositing amorphous silicon on a glass substrate and then forming a metal layer to crystallize it.

A metal molecule adsorption step of heating a glass substrate to a reaction temperature for chemical adsorption at a temperature at which pyrolysis does not occur and introducing a source gas as a compound containing a metal into a process space to chemisorb metal molecules onto a glass substrate on which amorphous silicon is formed. :

The metal molecules having a uniform distribution by the chemisorption of the metal molecules are disposed on the amorphous silicon layer on the glass substrate, and a plurality of amorphous silicon particles are included in the planar boundary region occupied by the metal molecules, thereby occupying the metal molecules. Forming a metal distribution region in which a clustered region of silicon particles per metal element is arranged by a region:

The metal distribution region forming step includes a surplus gas removing step of purging and removing surplus source gas that is not chemisorbed:

In the state where the metal molecules are arranged, the glass substrate is heated to a pyrolysis temperature to pyrolyze radicals other than the amorphous silicon and the chemically adsorbed metal element, or react with radicals other than the amorphous silicon and the chemically adsorbed metal element by introducing a reaction gas. And a metal layer forming step of obtaining a metal layer having low concentration uniform distribution by purging only metal elements in the metal distribution region by purging.

Here, the metal included in the source gas is characterized in that any one or two or more of Ni, Al, Ti, Ag, Au, Co, Sb, Pd, Cu.

Here, the metal layer is characterized by being performed by ALD (Atomic Layer Deposition).

In addition, the metal layer is characterized by being carried out in a single atomic layer thickness or less by one cycle of ALD.

As described above, the present invention forms a metal catalyst layer that maintains an appropriate distribution of metal particles for forming a crystallization nucleus in an amorphous silicon layer, thereby providing a metal catalyst layer on a glass substrate with a uniform concentration even though a low concentration of metal particle distribution. There is provided a process for manufacturing a polycrystalline thin film transistor display substrate which is formed to fundamentally reduce contamination of a channel region.

That is, as described above, in order to perform the low temperature heat treatment, the formation of the metal catalyst layer of amorphous silicon is inevitable, and at this time, the problem that the input catalyst metal should be approached most fundamentally under the inevitable conditions acting as a contaminant in the channel region, The formation of a metal catalyst layer that maintains an appropriate distribution of metal particles for forming crystallization nuclei in an amorphous silicon layer.

As a result, when a metal catalyst layer is formed on a glass substrate with a uniform distribution even though it has a low concentration of metal particles, contamination of the channel region by metal particles, such as crystal nuclei by MIC and lateral induction by MILC, is fundamentally prevented. It can be prevented.

To this end, the present invention deposits metal particles on a glass substrate, and determines a clustering region of a plurality of amorphous silicon particles as a region occupied by the metal molecules by using the size of the metal molecules, and then removes non-metallic components from the metal molecules. Therefore, only one metal particle is disposed in the clustered region.

In addition, the present invention provides a method capable of sufficiently coping with the large area of the display substrate which cannot be obtained by sputtering, especially when a nickel metal layer is applied using a chemical adsorption method.

In addition, it enables thin and uniform coating of the atomic layer or less that cannot be obtained by a method such as a general CVD method or atomic layer deposition (ALD).

Referring to the present invention through an embodiment for forming a nickel metal layer on the amorphous silicon layer, first, the ALD (Atomic Layer Deposition) device as shown in Figure 1 is applied to the device for forming a metal layer according to the present invention.

That is, a reaction chamber 10 providing a process space is formed, and a source gas supply for supplying a source gas for chemically adsorbing metal molecules and a reaction gas for thermally decomposing and reacting the adsorbed metal molecules to the reaction chamber. The apparatus 12 and the reaction gas supply device 14 are connected.

Each supply device and the reaction chamber 10 are connected to a supply pipe, and a high speed valve (not shown) is mediated to adsorb fine thin films, and an exhaust path 16 and a purge gas supply device for discharging excess gas ( 18) is connected.

On the other hand, a heating device 20 for performing pyrolysis of the glass substrate 100 is installed in the reaction chamber, and the boat is provided with a lifting device (not shown) for inputting the glass substrate into the reaction chamber.

In addition, the reaction chamber may be equipped with a plasma generating device for creating a plasma environment in order to excite the reducing material.

However, the present invention is not necessarily limited to such a device concept, and for example, when using a carrier gas, each gas supply device will be different, and the illustrated is a single sheet of glass substrate for processing a glass substrate for explaining the concept. If a treatment device or a batch treatment device for treating a plurality of glass substrates is applied, the structure of the heating device or the boat will be different.

As a result, when the nickel metal layer is formed on the amorphous silicon layer according to the present invention, FIG. 2 is a conceptual diagram illustrating that the nickel molecules are chemisorbed by Ni (CP) 2 having a predetermined occupation area on the amorphous silicon. 3 is a side conceptual view illustrating a step of forming a metal layer according to the present invention.

That is, when Ni (CP) 2 is introduced into the reaction chamber as a source gas in the state where the reaction chamber is formed at about 130 ° C to 190 ° C by the heating device, the glass substrate is specifically chemisorbed onto the amorphous silicon layer ( 2 and 3a to 3c).

At this time, the nickel molecular layer of less than 1 layer is chemisorbed by the self-limiting mechanism, and a purge gas is introduced and discharged to discharge the surplus gas which is not chemisorbed to the outside of the process space.

Here, the surplus gas is meant to include the glass substrate and the physically adsorbed nickel molecules, by removing it through the purge gas, by the distribution of the nickel molecule layer by the magnetic limitation uniform on the amorphous silicon layer (glass substrate: 100) Nickel molecules are disposed.

One nickel molecule is disposed on the amorphous silicon layer with an occupied area by its size.

As a result, one nickel molecule disposed on the amorphous silicon layer includes the plurality of amorphous silicon particles 26 in the planar region D.

That is, the cluster region D of the amorphous silicon particles is determined by the region of one nickel molecule chemisorbed by magnetic limitation.

In other words, the molecular structure is different depending on the source gas having a molecular formula, and the size of the cluster region determined by the source gas is also changed, so that the cluster region (D) of amorphous silicon particles containing one metal particle is included. The size of will be different.

According to the characteristics of the chemisorption, the present invention includes the step of forming a clustered area, and the clustered areas are uniformly distributed so that the concentration can be controlled in a low concentration area and the clustered area per one metal particle having a uniform distribution. It can be formed.

On the other hand, in the existing ALD process, the high-density thin film according to the self-limiting properties and the metal molecules cannot be expected sufficiently, and a plurality of layers are superimposed to compensate for this, but in the present invention, the cluster region is converted into an advantage by converting these properties into advantages. It is to be adjusted according to the concentration of the metal particles.

Source gas for forming such a clustered region, its flow and composition temperature are to be determined experimentally. Such chemical adsorption is performed by using a metal compound gas without using a target metal panel such as sputtering, and forming a magnetic field. This eliminates the need for a large area glass substrate.

Next, to remove radicals other than the amorphous silicon and the chemisorbed nickel element from the nickel molecule, that is, to form a metal layer on the amorphous silicon, a pyrolysis temperature is formed or a reaction gas is introduced into the process space below the pyrolysis temperature.

The reaction gas is a reducing gas such as H2 or NH3, an inert gas such as Ar or N2, an oxidizing gas such as O2 or N2O, or a gas excited by the plasma, and the reaction gas reacts with the CP so that the metal particles are formed in the amorphous silicon layer. Residues in the colony are removed and by-product mCnH2n + 2 is generated and purged and removed.

That is, one nickel is disposed in one cluster region D of the amorphous silicon layer by Nicp2 + H2-> Ni + mCnH2n + 2, and the collection of the cluster regions forms a nickel metal layer.

It is discharged to the outside of the process space by the by-product purge gas, and a nickel layer of low concentration is formed on the amorphous silicon layer by arranging one nickel in the cluster region having the uniform distribution and the width can be adjusted. (See Figure 3c).

This nickel layer is sufficient in one cycle in the ALD, it is formed to a thickness of less than the atomic layer.

Here, the formation of the thickness below the atomic layer means that the average thickness of the metal layer is formed below the atomic layer by the metal atom having a low concentration arrangement according to the present invention.

As described above, according to the present invention, by forming a metal layer that maintains an appropriate distribution of metal particles for forming crystallization nuclei in an amorphous silicon layer, contamination by metal particles in the metal-induced side crystallization process is prevented, thereby There is an effect that the characteristics are maintained.

In addition, by adopting the formation of the metal layer by chemisorption, it is possible to control the large area and thin thickness which is impossible with the conventional sputtering method, and to apply the uniform metal / metal compound of the atomic layer or thickness which is impossible by the conventional general CVD. There is.

Claims (6)

A method of manufacturing a polycrystalline thin film transistor display substrate in which amorphous silicon is deposited on a glass substrate and then a metal layer is formed to crystallize it. A metal molecule adsorption step of heating a glass substrate to a reaction temperature for chemical adsorption and introducing a source gas containing metal into the process space to chemisorb metal molecules onto a glass substrate on which amorphous silicon is formed: The metal molecules having a uniform distribution by the chemisorption of the metal molecules are disposed on the amorphous silicon layer on the glass substrate, and a plurality of amorphous silicon particles are included in the planar boundary region occupied by the metal molecules, thereby occupying the metal molecules. Forming a metal distribution region in which a clustered region of silicon particles per metal element is arranged by a region: The metal distribution region forming step includes a surplus gas removing step of removing the surplus source gas that is not chemisorbed by removing it from the process space: The metal layer forming step of separating the amorphous silicon and the chemically adsorbed metal elements in the state where the metal distribution region is formed and then removing them by removing them out of the process space to obtain only the metal elements in the metal distribution region to obtain a metal layer having a uniform distribution A method of manufacturing a polycrystalline thin film transistor display substrate is included. The method of claim 1, wherein the metal included in the source gas is manufactured of polycrystalline thin film transistor display substrate, characterized in that any one or a combination of two or more of Ni, Al, Ti, Ag, Au, Co, Sb, Pd, Cu. Way. The method of claim 1, wherein the metal layer is formed by atomic layer deposition (ALD). 4. A method according to claim 3, wherein the metal layer is formed with the thickness of the atomic layer of the metal which is adsorbed by one cycle of ALD. The method of claim 1, wherein the radical separation in the metal layer forming step is performed by thermal decomposition by forming a process space at a temperature for thermally decomposing the metal molecules constituting the metal layer. The method of claim 1, wherein the radical is separated in the metal layer forming step, wherein a reaction gas reacting with the radical is introduced into a process space.

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