KR100972292B1 - Method for chemical vapor deposition - Google Patents

Abstract

The present invention discloses a chemical vapor deposition method capable of depositing a good film on a substrate by reducing the generation of foreign matter on the deposited film when forming the deposited film in the chemical vapor deposition chamber used in the liquid crystal display device. The present invention discloses a method of bringing a substrate into a PECVD chamber into which a deposition film is to be formed, placing the substrate on a susceptor in the chamber, then closing the chamber and maintaining a pressure state for deposition; Generating a plasma particle by applying 1 power to the plasma electrode; forming a thin first deposition film on the substrate by the plasma particle; and continuing the first power while the first deposition film is formed. And increasing the second power higher than the first power to generate plasma particles to continuously deposit the second deposition film, and to clean the surface of the substrate on which the second deposition film is formed.

Chemical, foreign substance, high pressure, chamber, plasma

Description

Chemical vapor deposition method {METHOD FOR CHEMICAL VAPOR DEPOSITION}

1 is a view showing the structure of a chemical vapor deposition equipment commonly used.

2A and 2B illustrate a chemical vapor deposition process according to the prior art.

3 is a view showing the appearance of foreign matter on a substrate deposited according to the prior art.

4A-4C illustrate a chemical vapor deposition process in accordance with the present invention.

5 illustrates the structure of a substrate on which a deposition film is formed in accordance with the present invention.

* Description of the symbols for the main parts of the drawings *

31: power supply unit 32: gas injection unit

33: plasma electrode 34a: low energy plasma particles

34b: high energy plasma particle 35: substrate

36: suceptor 37: vehicle

42a: first deposited film 42b: second deposited film

100: PECVD chamber

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition method, and more particularly, to a chemical vapor deposition method in which foreign matters are not formed in a deposition film on a substrate on which chemical vapor deposition is performed.

In general, thin film transistors applied to driving circuits of thin film transistor liquid crystal display (TFT-LCD) devices or static random access memory (SRAM) devices are formed on substrates much larger than those of conventional bulk transistors. . Therefore, forming a uniform thin film is much more difficult than in the case of bulk transistors. At this time, in order to deposit the thin film uniformly, it is important to uniformly form the density of the plasma. For this purpose, plasma enhanced chemical vapor deposition (PECVD) equipment using a showerhead type flat electrode is generally used.

In particular, a liquid crystal display device includes a plurality of gate bus lines and data bus lines vertically arranged on a transparent insulating substrate to form a large number of unit pixel regions, and each unit pixel region is made of indium tin oxide (ITO) transparent metal. An array substrate on which pixel electrodes and thin film transistors (TFTs) for switching operations are disposed, and a color filter substrate composed of a number of RGB color filters corresponding to the unit pixels are bonded to each other with liquid crystal molecules interposed therebetween. Doing.

In particular, the array substrate may be sequentially coated with a metal film, an insulating film, and an amorphous silicon film on the insulating substrate through a 4, 5, 6, 7 mask process, and then etched to form a gate bus line, a data bus line, a channel layer of a TFT, and the like. Source / drain electrodes are formed and made.

1 is a view schematically showing the configuration of a typical plasma chemical vapor deposition apparatus.

Referring to FIG. 1, in a typical plasma chemical vapor deposition apparatus, a reaction chamber 11 having an open top is covered by a chamber cover 12. Accordingly, the reaction space is blocked by the reaction chamber 11 and the chamber cover 12 is formed. In addition, an O-ring is inserted between the reaction chamber 11 and the chamber cover 12 to effectively seal the reaction space.

In the reaction space, a susceptor 6 capable of being vertically transported by the transfer means 7 and electrically grounded is provided. At this time, the substrate 5 to be deposited is mounted on the susceptor 6, and a heating means (not shown) for heating the substrate 5 is mounted inside the susceptor 6.

Meanwhile, a showerhead plasma electrode 3 connected to an external RF generator is installed in the reaction space provided above the susceptor 6. The plasma electrode 3 is hollow and the gas injection tube 2 is installed to be connected to the inside of the plasma electrode 3. In the bottom surface of the plasma electrode 3, a plurality of injection holes 3a having a diameter of several mm are formed at intervals of several cm.

Accordingly, the gas injected into the plasma electrode 3 by the gas injection tube 2 is injected into the reaction space through the injection hole 3a, and the gas injected into the reaction space is exhausted through the gas exhaust pipe. . In addition, the plasma electrode 3 is made of a metal material such as stainless steel or aluminum, and the surface thereof is usually anodized to prevent arc generation by plasma.

In addition, the side wall of the reaction chamber 11 is provided with a slot valve (slot valve) for determining the communication between the load lock portion (not shown) and the reaction space, from the load lock portion on the susceptor (6) In order to transfer the substrate 5, the slot valve must be opened.

Therefore, the plasma chemical vapor deposition chamber having the structure as described above makes the substrate into which the high energy power is injected from the high frequency power supply unit 1 by the susceptor 6 and the plasma electrode 3 to inject the plasma into the plasma state. A vapor deposition film is formed on (5).

2A and 2B illustrate a chemical vapor deposition process according to the prior art.

As shown in FIG. 2A, the substrate 5 is moved into a plasma enhanced chemical vapor deposition (PECVD) chamber 10 to form a deposition film on the substrate 5 used in the liquid crystal display manufacturing process. It is a process of forming an insulating film by chemical vapor deposition.

When the substrate 5 is introduced into the PECVD chamber 10, the pressure in the PECVD chamber 10 is set to a pressure for deposition, and then a high power energy is supplied from the power supply unit 1 to the plasma electrode 3. ) Is applied.

As a gas, which is a material of an insulating film deposited on the substrate 5, is injected through the gas injection tube 2, high energy plasma is generated by a high electric field between the susceptor 6 and the plasma electrode 3. Is generated.

That is, a deposition film is formed on the substrate 5 seated on the susceptor 6 while the gas injected through the plurality of injection holes of the plasma electrode 3 is converted into a high energy plasma.

Then, as shown in FIG. 2B, when an insulating film (not shown) having a predetermined thickness is deposited on the substrate 5 by plasma particles, the power of the power supply unit 1 is turned off. The injection of the supplied gas is stopped.

In the chamber 10, the plasma shower is stopped for deposition and the growth of the insulating film on the substrate 5 is stopped.

After the deposition process is finished, the cleaning process is performed to remove foreign matters formed on the surface of the deposition film, and then another film formation process is performed.

However, when the substrate to be subjected to the deposition process is brought into the chemical vapor deposition chamber as described above, the plasma is immediately generated by applying a pressure and a high pressure power, and then deposited. There is a problem created.

3 is a view illustrating a state in which foreign matter is generated on a substrate deposited according to the prior art.

As shown in FIG. 3, when the deposition film 13 is formed on the substrate 5 by the high plasma energy under the deposition pressure from the beginning in the plasma chemical vapor deposition chamber, the energy of the foreign matter present in the chamber is also increased. The deposition film surface is strongly deposited or a large amount of foreign matter is present in the deposition film 13 by internal penetration.

As such, when foreign matter is generated on the deposition film 13, the defects cannot be solved even in a deposition process for forming another film quality, which causes a decrease in manufacturing yield.

In the cleaning process after the deposition film is formed, the foreign matter strongly adhered to the deposition film and the foreign matter penetrated into the deposition film are not removed. Therefore, the foreign matter cannot be removed even in a subsequent process.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemical vapor deposition method capable of preventing foreign substances from being formed on a deposition film by plasma having high energy when depositing an insulating film on a substrate of a liquid crystal display device.

In order to achieve the above object, the chemical vapor deposition method according to the present invention,

Importing a substrate into the PECVD chamber to form a deposition film;

Placing the substrate on a susceptor in the chamber, then closing the chamber and maintaining pressure for deposition;

Generating plasma particles by applying a first power to a plasma electrode at a power source of the PECVD chamber;

Forming a first deposition film on the substrate by the plasma particles;

Continuously depositing the second deposition film by generating plasma particles by raising the first power to a second power higher than the first power while the first deposition film is formed; And

Performing a process of cleaning a surface of the substrate on which the second deposition film is formed; Characterized in that it comprises a.

Here, the first power for forming the first deposition film is such that foreign matter forming particles together with the plasma particles in the chamber does not penetrate into the first deposition film, and the first deposition film and the second power The secondary deposition film is characterized in that it is formed in the same PECVD chamber.

In particular, the formation time of the first deposition film is less than the formation time of the second deposition film based on the entire deposition film processing time, and the first deposition film and the second deposition film is characterized in that the deposition under the same pressure.

According to the present invention, instead of generating a plasma by applying a high power to the substrate loaded into the chemical vapor deposition chamber from the beginning, the plasma is first generated by a low power for a short time to generate the film quality, and then high power By generating a plasma of the deposition film to prevent the formation of foreign matter on the deposition film.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

4A-4C illustrate a chemical vapor deposition process according to the present invention.

As shown in Fig. 4A, when depositing each insulating film, active layer, protective film, etc. during the manufacturing process of the liquid crystal display device on the substrate 35 to be deposited by plasma chemical vapor deposition, the substrate is chemical vapor deposition chamber Carried out in the deposition process.

A protective film is formed in the PECVD chamber 100. The substrate 35 loaded into the PECVD chamber 100 is fixed to a susceptor 36 disposed at the bottom of the PECVD chamber 100, and the gas flows from the plasma electrode 33. In this way, a gas layer to be a material of the insulating film is formed on the substrate 35.

At this time, the power of the power supplied from the power supply unit 31 to the low power to convert the gas particles into low-energy plasma particles (34a) having electrical characteristics to make a plasma shower.

At this time, a thin deposition film is formed on the substrate by the low-energy plasma particles 34a, which have low kinetic energy of the plasma particles due to low power, and low kinetic energy of foreign matter in the PECVD chamber 100. This is to prevent foreign matter from penetrating.

That is, the plasma particles due to the low kinetic energy do not penetrate into the deposition film, and because they exist only with weak adhesion on the deposited film, they can be removed cleanly in the cleaning process, so that no foreign matter remains in the deposition film region.

In the susceptor 36 in the PECVD chamber 100, heat is applied at a deposition temperature in order to deposit an insulating film on the substrate 35, and moving means for supporting the susceptor 36 ( In 37), the susceptor 36 mounted on the substrate 35 is moved up and down by a predetermined distance so that the deposition film having a desired thickness can be grown.

As shown in FIG. 4A and when a low power power is applied and the thin first deposition film is grown on the substrate 35 by the plasma particles 34, the power is increased.

Although not shown, 32 is a gas inlet and 31 is a power supply.

Thus, as shown in FIG. 4B, a high power source is applied to the plasma electrode 33, and high energy plasma particles 34b having a high kinetic energy are formed to continue on the first deposition film. 2 form a deposited film.

Plasma particles 34b are showered on the substrate 35 by a strong electric field formed from the plasma electrode 33 and the susceptor 36, and the plasma particles adhere to and are deposited on the substrate 35.

At this time, the first deposition film was formed by a plasma having a weak kinetic energy by a low power supply, and thus the kinetic energy of the foreign matter was also weakly moved, and the number of the foreign matters was small. I never do that.

As described above, the second deposition film is formed on the substrate 35 in a state where the number of plasma particles and foreign matters activated by the high kinetic energy is smaller, and at this time, even if a small foreign material is present on the second deposition film, Will be removed cleanly.

Since the inside of the PECVD chamber 100 is applied with high power by increasing the power of the power supply in a state where the foreign matters are kept small, the deposition process continues without increasing the number of foreign matters.

As illustrated in FIG. 4C, when the deposition film is formed on the substrate 35 as described above, the power supply of the PECVD chamber 100 is turned off to complete the deposition process.

The first deposition film and the second deposition film are sequentially formed on the substrate 35, and a small number of foreign substances are present on the second deposition film.

Such foreign matters are mostly removed in the cleaning process because of poor adhesion to the deposited film, thereby reducing the formation of a poor deposited film.

In this case, since the formation conditions and the use gas of the first deposition film (42a of FIG. 5) and the second deposition film (42b of FIG. 5) are the same, and only the magnitude of the plasma generation voltage is different, the deposition of the same film but having the double film property .

5 is a view showing the structure of a substrate on which a deposition film is formed according to the present invention.

As shown in FIG. 5, a deposition film is formed on the substrate 35 by a low power plasma and a high power plasma in a PECVD chamber.

The first deposition film 42a is formed on the substrate in a thin thickness, and the second deposition film 42b is formed thereon.

Since the high power deposition is continuously performed after the deposition by the low power for the actual deposition, it appears as a single deposition film, but precisely a thin film deposited on the thin film is deposited by a high plasma energy particles to the structure that is laminated.

The number of foreign matters present on the substrate is significantly smaller than that of the conventional deposition substrate, and the small amount of foreign matters can be mostly removed by a post-process cleaning process.

As described in detail above, when the deposition film is formed on the substrate in the plasma chemical vapor deposition chamber, the foreign material is removed on the deposition film by sequentially generating the deposition film by a low power plasma, a high power plasma step It can work.

The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art without departing from the gist of the present invention as claimed in the following claims.

Claims (5)

Importing a substrate to form a deposited film into a PECVD chamber; Placing the substrate on a susceptor in the chamber, then closing the chamber and maintaining pressure for deposition; Generating plasma particles by applying a first power to a plasma electrode at a power source of the PECVD chamber; Forming a first deposition film on the substrate by the plasma particles; Continuously depositing the second deposition film by generating plasma particles by raising the first power to a second power higher than the first power while the first deposition film is formed; And A process of cleaning the surface of the substrate on which the second deposition film is formed; The first power for forming the first deposition film is such that foreign matter forming particles together with the plasma particles in the chamber does not penetrate into the first deposition film, Forming time of the first deposition film is a chemical vapor deposition method, characterized in that less than the formation time of the second deposition film on the basis of the entire deposition film processing time. delete The method of claim 1, And the first and second deposition films are formed in the same PECVD chamber. delete The method of claim 1, The first vapor deposition film and the second deposition film is a chemical vapor deposition method characterized in that the deposition under the same pressure.

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