KR100701449B1 - Apparatus for catalytic metal doping for low temperature poly silicone crystallization and method using the same - Google Patents

Abstract

The present invention is a metal catalyst doping apparatus and doping for low temperature silicon crystallization to ensure reproducibility and stability in the process of low temperature poly-crystalline silicon (a-Si) coated on a glass or polymer substrate The method is disclosed. The present invention is a chamber, a heater is installed in the chamber and the substrate is mounted and moveable, the opposite electrode plate disposed on the same plane as the heater, a linear drive unit installed in the chamber and linearly moving, the linear And a sputter gun linearly moved by a drive unit, the sputter gun including a cathode electrode coupled to the linear drive unit and a cathode electrode plate disposed in a direction facing the counter electrode plate.

Plates, Substrates, Sputtering, Catalysts, Sputters, Glass, Polymers

Description

{Apparatus for catalytic metal doping for low temperature poly silicone crystallization and method using the same}

1 is a perspective view schematically showing a metal catalyst doping apparatus for explaining a first embodiment according to the present invention.

2 is a view for explaining the structure of the sputter gun and the arrangement relationship with the counter electrode plate in the first embodiment of the present invention.

3 is a view for explaining a plasma density graph of an embodiment according to the present invention.

4 is a perspective view schematically showing a metal catalyst doping apparatus for explaining a second embodiment according to the present invention.

FIG. 5 is a view for explaining the arrangement of the sputter gun and the arrangement of the counter electrode plates in the second embodiment of the present invention.

FIG. 6 is a graph showing sputtering yield according to the inclination angle of the sputter gun in the metal doping apparatus according to the second embodiment of the present invention.

The present invention relates to a metal catalyst doping apparatus and a doping method for silicon low temperature crystallization, and more particularly to a process of low temperature poly-crystalline silicon (a-Si) coated on a glass or polymer substrate The present invention relates to a metal catalyst doping apparatus and a doping method for silicon low temperature crystallization capable of ensuring reproducibility and stability.

In general, the field of display is one of the most advanced results obtained as a result of advanced scientific developments following semiconductor memory. Conventional cathode-ray tube (CRT) did not overcome the limitations of spatiality due to the uniqueness of the device, and efforts to replace it have been made through TFT LCD (Thin Film Transistor Liquid Crystal Display) and OLED (Organic Light Emitting Diodes). ), FED (Field emission display), PDP (Plasma display Panel) has been tried in various ways. Among these methods, the OLED method is a field that has recently attracted much expectation as the next generation display. The OLED light and was not only very fast to another display mode ^10-6 seconds domain response speed compared to the use of so that the self-light emission of the thin-film, thin, thick, wide viewing angle, using the electric power was small, the display of the scroll-type Has the possible advantages. Active matrix (AM) OLED among OLED methods adopts thin film transistor (TFT) as a TFT LCD as a base, and thus requires a crystalline silicon process that has a faster electron transfer speed than amorphous silicon for thin film transistors. I am doing it.

Transparent materials that are widely used as display substrate base materials include general glass and quartz, and glass materials are more preferred for business purposes. There are two methods of making grain silicon on a glass substrate: a direct method such as hot wire CVD (HWCVD) and an indirect method such as an Excimer Laser Annealer (ELA). In the case of silicon, thermal energy of 700 ° C. or more is required to achieve a phase change from the amorphous phase to the crystal grain. However, since the glassization temperature of glass is about 640 ° C., which is lower than the silicon phase change temperature, it is not easy to crystallize amorphous silicon deposited on the glass substrate using only thermal energy. Therefore, it is necessary to make silicon grains at a temperature lower than the temperature at which the glass causes the phase change, and this process is emphasized, and the process is called low temperature polysilicon (hereinafter referred to as "LTPS" or "low temperature poly") crystallization process.

This LTPS crystallization process technology, LTPS crystallization process technology for the heat treatment by doping (doping) the metal material that acts as a catalyst to the amorphous silicon thin film to less than 10 ¹³ per unit area has been developed, but the ultra-thin thickness of the desired metal material Doping into a thin film having a problem is not easy.

Accordingly, the present invention has been proposed to solve the above problems, and an object of the present invention is to form a mono-layer (ML, mono-layer) of metal particles (10 ¹³ atoms / cm 2 or less, for reference). Metal catalyst doping apparatus and doping method for silicon low temperature crystallization, which can attain reproducibly matching the thickness of 0.1 Å or less, which is the amount of deposition at a desired doping level, at a time of about 10 ¹⁵ atoms / cm 2). It is.

In order to achieve the above object, the present invention is a chamber, a heater is installed in the chamber and the substrate is seated on the upper side, the counter electrode plate disposed on a plane on the upper portion of the heater, the linear drive unit installed on both sides of the chamber, And a sputter gun linearly moved by a linear drive unit, the sputter gun coupled to the negative electrode coupled to the linear drive unit, the negative electrode coupled to the negative electrode plate disposed in a direction facing the counter electrode plate. It provides a metal catalyst doping apparatus for silicon low temperature crystallization comprising.

The sputter gun may be fixed to a direction in which the target surface maintains any one of angles from 0 ° to ± 90 ° from the substrate direction.

The cathode electrode is preferably provided with a cooling water passage therein.

The sputter gun is preferably disposed in such a manner that the side surfaces of the cathode electrode plate and the top surface of the cathode electrode plate are covered.

The sputter gun has a width in the substrate transfer direction of less than 10 ~ 50mm, the cathode electrode plate is preferably made of nickel or nickel alloy.

In addition, the present invention is a chamber, the heater is installed in the chamber and the substrate is mounted on the upper side, the counter electrode plate disposed in a plane on top of the heater, the linear drive unit installed on both sides of the chamber, the linear by the linear drive unit A doping method using a metal catalyst doping apparatus for silicon low temperature crystallization including a sputter gun that moves in a moving manner, wherein the sputter gun moves a moving speed within a moving speed of 1 to 6 m per minute and the silicon low temperature crystallization doping the metal catalyst It provides a doping method using a metal catalyst doping apparatus for.

Preferably, the distance between the sputter gun and the counter electrode plate is within a range of 50-100 mm.

The power applied to the sputter gun preferably has a condition of 300 to 1,000 V, or 13.56 MHz, 600 W, or 1.0 to 10 KHz, 200 to 500 W.

It is preferable that the flow rate of the gas injected into the chamber is doped with the metal catalyst in the range of 5 to 100 sccm.

The pressure of the gas injected into the chamber is preferably doped with a metal catalyst in the state of 5 X 10 ^-3 ~ 5 X 10 ^-1 Torr.

The gas injected into the chamber is preferably made of any one of argon, neon, nitrogen, helium or a mixture of these gases.

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

1 is a perspective view for explaining a first embodiment according to the present invention, showing a metal catalyst doping apparatus for low temperature silicon crystallization. The metal catalyst doping apparatus for silicon low temperature crystallization shown in the present invention is a drive source such as a chamber 1, a heater 3, a counter electrode plate 5, a motor M, etc. capable of forming a vacuum, and the drive source. It includes a linear drive (7) for transmitting a driving force in the chamber (1), and a sputter gun (9) coupled to the linear drive.

The chamber 1 is formed in a substantially rectangular parallelepiped shape and has a structure in which space is provided. And it is preferable that the inside of the chamber 1 is made into a vacuum state.

The heater 3 may be placed on the substrate (G) thereon. And it is preferable that the counter electrode plate 5 is arrange | positioned on the surface and extension line in which the said heater 3 is arrange | positioned.

The heater 3 preferably forms a structure that is connected to a temperature control device (not shown) so that the substrate G may be evenly heated to about 350 ° C. during the doping process. In addition, the counter electrode plate 5 may include a heater (not to change the electric field that may vary due to a change in the distance between the cathode and the counter electrode provided to the sputter gun 9 as the sputter gun 9 moves linearly). It is preferable that it is comprised so that the surface of 3) may be equipotential.

In the present invention, the counter electrode plate 5 including the heater 3 may be formed in a conventional structure which can be transferred together in a state where the substrate G is seated. That is, the heater 3 may have a structure in which the substrate G may be raised and the transfer and heating of the substrate G may be performed in real time. The heater 3 of the present invention can be any structure that can simultaneously transfer the substrate G while heating it.

The linear drive unit 7 is for linearly moving the sputter gun 9 in the chamber 1, a drive source consisting of a motor M, a drive shaft 21 rotating by the drive source, and the drive shaft 21 A pair of driving pulleys (23, 25) rotated by), a pair of driven pulleys (27, 29) disposed in a position corresponding to the drive pulleys (23, 25), and the drive pulleys (23, 25) ) And belts 31, 33 disposed between the driven pulleys 27, 29. The belts 31 and 33 may be made of metal. The linear drive 7 may be a conventional one capable of transferring the doping module 9, but is not limited to the example shown in the drawings in the present invention. In particular, the linear driver 7 may be any structure as long as the substrate G and the doping module 9 linearly move relative to each other.

As shown in FIG. 2, the sputter gun 9 includes a cathode electrode 51 coupled to the linear driving unit 7, and a cathode electrode plate disposed in a direction facing the counter electrode plate 5. 55). In particular, it is preferable that the sputter gun 9 is arranged to be linearly movable (moving the direction of the arrow or the opposite direction in FIG. 2) at a position where the distance d stands out with respect to the counter electrode plate 5.

The cathode electrode 51 is provided with a cooling water passage for cooling the heat therein. The cooling water passage 51a is arranged in the longitudinal direction of the cathode electrode 51 and is connected to a separate cooling water supply / circulator (not shown). The cooling water passage 51a is to maintain the surface characteristics of the negative electrode plate 55 by maintaining a constant temperature of the negative electrode plate 55 (also referred to as a 'target') while the cooling water flows.

On the outer circumferential surface of the sputter gun 9, a ground shielding member 57 has a dark space of 2 mm so as to cover a portion other than a portion where the negative electrode plate 55 is disposed, and a dark space (space without plasma). It is preferred to be spaced apart and joined. The shielding member 57 forms an equipotential with the heater surface and the counter electrode plate 5, so that an electric field can be formed between the target surface and the glass substrate. The sputter gun 9 can greatly reduce the plasma density enhancement by the magnetic field by not disposing the permanent magnet on the cathode electrode 51. As such, by not inserting the permanent magnet into the transfer sputter gun in the chamber 1, it is possible to suppress the plasma density increase due to the magnetic field and to realize the doping of the catalytic metal by the electric field which is simply uniformly formed.

4 is a perspective view for explaining a second embodiment according to the present invention, Figure 5 is a view showing the main part of Figure 4, showing another example of a metal catalyst doping apparatus for low temperature silicon crystallization. The second embodiment of the present invention describes only the other parts compared to the first embodiment described above, and the same parts as the first embodiment are replaced with the description of the first embodiment described above.

The second embodiment of the present invention differs in that the sputter gun 9 and the counter electrode plate 5 including the substrate are disposed perpendicular to each other. That is, the sputter gun 9 of the second embodiment of the present invention has the same structure as that of the first embodiment described above, except that the sputter gun 9 is provided in the direction in which the surface of the counter electrode plate 5 faces. The direction that the surface of the negative electrode plate 55 faces is arranged at different angles θ. This angle was arrange | positioned so that it may be adjusted in the range of +/- 90 degrees (right angle), as shown in FIG. 5, when the state which the negative electrode plate and the glass substrate oppose is set to 0 degree. This can achieve an effect of artificially floating the distance between the cathode electrode plate and the substrate and reducing the deposition rate to a maximum of less than half compared to when facing each other at 0 ° by preventing the uniform electric field formation. Therefore, it is preferable that the angle θ formed between the substrate and the cathode electrode plate can be adjusted to 0 °, ± 45 °, and ± 90 °. That is, in the second embodiment of the present invention, it is preferable that the sputter gun 9 is rotatably hinged to the linear drive 7, which is a portion supporting the sputter gun 9. This structure means that the direction of the sputter gun can be inclined at an angle (± θ, an angle capable of rotating left and right with respect to the vertical line in the drawing) with the substrate G. Although the detailed illustration of the rotating structure of the sputter gun 9 is omitted, it is also possible to have a structure in which the rotation can be controlled by a separate motor or the like.

FIG. 6 is a curve showing the sputtering yield according to the inclination angle (θ) of the sputter gun with respect to the substrate plane direction, where the x axis represents an angle of the inclined target and the y axis represents a tendency of generalized values. In some cases, the deposition rate (%) according to the angle change is shown. It can be expressed as a result d, which is the sum of sputter deposition (a) in which doping takes place and re-sputter (e) in the surface of the substrate, all of which can be obtained as a function of the angle of the sputter gun with the substrate.

The sputtering deposition rate 21 is directly proportional to the electrical energy value applied to the target, and if the energy value applied to the target is reduced, the sputtering deposition tendency shown by the curve (a) of FIG. 6 may be reduced to the curve (b). It can be easily counted. It can be seen that sputter deposition may vary depending on the inclination angle between the target surface and the substrate, even if a certain amount of energy is applied to the target. When the target plane is shifted by ± 90 degrees, the sputter deposition is reduced by half compared to when the target face is facing 0 degrees.

On the other hand, if the energy value applied to the target is reduced, the re-sputtering phenomenon occurring on the surface of the substrate also tends to decrease remarkably from the curve (e) to the curve (f), and these resputtering values (f) and sputtering deposition are shown. The same value as the pure doping curve (C) is obtained as the sum of the values (b).

Therefore, in the present invention, the amount of doping may vary according to the angle of the sputter gun facing the substrate surface, so that the target metal is transported while maintaining a constant angle at the time of transport, so that the catalytic metal doping is performed.

On the other hand, the cathode electrode plate 55 is preferably made of nickel.

The method of doping the metal catalyst of the thin film using the metal catalyst doping apparatus for silicon low temperature crystallization of the present invention thus made will be described.

In the method of doping the metal catalyst of the thin film using the metal catalyst doping apparatus for silicon low temperature crystallization of the present invention, the conditions applied are as follows. The power applied to the sputter gun is preferably a condition of 300 to 1,000 V, or 13.56 MHz, 600 W, or 1.0 to 10 KHz, 200 to 500 W. It is preferable that the flow rate of the gas injected into the chamber is doped with the metal catalyst in the range of 5 to 100 sccm. The pressure of the gas injected into the chamber is preferably doped with a metal catalyst in the state of 5 X 10 ^-3 ~ 5 X 10 ^-1 Torr.

In the present invention, the case where the cathode electrode plate 55 (catalyst metal) is nickel will be described as an example. When the cathode electrode plate 55 is fixed without being transported with respect to the substrate G, the typical deposition rate r is determined by the power of the sputter gun 9, between the sputter gun 9 and the substrate G. It is determined by the distance d. The thickness t of the thin film deposited on the substrate G is determined by the product of the deposition rate r and the time (s, exposetime) of the substrate G being exposed to the plasma.

Therefore, in order to reduce the thickness of the thin film deposited on the actual substrate, the entire substrate G is scanned (scanned) with respect to the stationary cathode electrode plate while the width of the cathode electrode plate 55 is shorter than the substrate length. Alternatively, the cathode electrode plate should be scanned at speed v for the entire substrate at rest. In other words, if the cathode electrode plate having a width of x mm is transported at a speed of v / min and scans the entire upper surface of the stationary substrate, and the deposition is performed, the time when the actual substrate G is exposed to the sputter gun 9 is negative electrode plate The width of 55 is proportional to the value obtained by dividing the total substrate length in consideration of the moving direction, and inversely proportional to the moving speed (relative to the substrate) of the negative electrode plate 55.

Therefore, the thickness (t) of the thin film on which the deposition material is deposited is the deposition rate (r) X {(the width of the negative electrode plate (x) / the total length of the substrate (l)) X {the total length of the substrate (l) / the speed of the sputter gun ( v)}, the formula must have two prerequisites, firstly, the width x of the cathode electrode plate 55 must be shorter than the length of the substrate G in the scanning direction. In the second condition, since the relative velocity v between the negative electrode plate 55 and the substrate G is necessary to deposit the entire substrate G, the negative electrode plate 55 or the substrate G must be used. It must move, so the relative speed of movement (v) must have a nonzero value.

In conclusion, in addition to the deposition rate determined according to the operating conditions of the cathode electrode plate 55, the width (x) of the cathode electrode plate 55 and the cathode electrode plate 55 are factors that can control the thickness of the thin film deposited on the actual substrate. ) And the substrate G only have a relative speed difference to establish a formula. At this time, the width x of the negative electrode plate 55 should be shorter than the length of the substrate G and the moving speed should have a positive value. This is described by the formula as follows.

  From here

x: cathode electrode plate width

l: substrate length

v: moving speed of sputter gun

When the nickel metal is deposited with the cathode electrode plate and the substrate stationary, the sputter gun having a deposition rate of about 4,000 kPa / min and the width x of the cathode electrode plate 55 is 40 mm (9). When the cathode is transported at a speed of 1 m per minute and passes through the entire substrate G, the thickness t of the thin film deposited on the surface of the actually stopped substrate becomes about 160 mW. In addition, when the feed rate of the cathode electrode plate 55 is transferred at 5 m / min, the thickness t of the thin film, which is 160 mW, is reduced to 1/5 to about 32 mW. Therefore, in the present invention, the width x of the preferred negative electrode plate 55 is configured to 10 to 50 mm, and the feeding speed of the negative electrode plate 55 to the substrate G is set to 1 to 6 m per minute.

When voltage V is applied to the negative electrode plate 55, the counter electrode plate 5 (the ground plate, the positive electrode plate relative to the negative electrode plate) and the potential difference V are formed to generate an electric field E between these electrodes. Is shown in FIG. 2.

Both the difference between the area ratio in the chamber (1) a large electrode (cathode electrode plate, a positive electrode plate) to ^{5 X 10 -3 ~ 5 X 10} -1 Torr filling the ionized gas in the area when a voltage is applied to a small area, the area between the The plasma is generated around the periphery. At this time, the factor that can be artificially applied is the external voltage V, and thus the physical quantity that is changed by the distance d between both ends is the electric field. If the charge q lies in the electric field E, the force it receives is accelerated by the force multiplied by the electric field. Therefore, it can be seen that the physical quantity applied to the electric charge for plasma ionization is the electric field E, and for this purpose, a factor that can be artificially changed is the distance d between the voltage V and the electrodes at both ends. Therefore, the plasma density is related to the electric field E. Even when the same voltage V is applied, the plasma density decreases to 1/2 when the distance d between the parallel electrodes 55 and 5 is doubled. . However, in general, in the sputtering concept of the cathode electrode plate and the ground, the area ratio is very large, so the cathode electrode plate can be considered as a point-type electrode, and the plasma density decreases exponentially as the distance between the electrodes at both ends increases. . Of course, sputtered particles also have a 45-degree radial emission, resulting in a decrease in deposition rate. Therefore, in the present invention, the distance between the preferred electrodes 55 and 5 is increased from the existing separation distance of 30 to 45 mm to 50 to 100 mm, and as a result, the deposition amount of about 32 에서 in FIG. 1 is reduced to 6 Å or less. The effect can be obtained.

In addition, the present invention includes a sputter gun 9 which omits the arrangement of the magnet so that the plasma is formed by an electric field without a magnetic field, thereby driving the magnet without the permanent magnet mounted on the sputter gun. This structure is relatively uniform and very low, as shown in the graph of FIG. 3, where the electric field E is formed only by the two electrodes 55 and 5, which is lower than 1/100 of the plasma compared to the magnetron sputter gun applied to all sputter deposition apparatuses. Plasma is formed at a density. Therefore, in this form, since the plasma density is lower than that of the general magnetron sputter cathode, it has a very low deposition rate of about 1/100 or less. Therefore, it is possible to obtain a result that the deposition rate, which was about 6 kW in the above description, is lowered to about 0.06 kW or less.

Therefore, in the metal catalyst doping apparatus for silicon low temperature crystallization of the present invention and the method using the same, it is possible to reproducibly match the thickness of 0.1 Å or less, which is the deposition amount of the desired metal doping level under the above conditions.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, in the present invention, since the sputter gun installed on the substrate surface proceeds at a constant speed and sputtering is performed, the metal material can be doped in a more uniform form. It is very effective for the process of converting amorphous silicon thin film deposited on the glass or polymer surface as needed to polysilicon.

In addition, the present invention can ensure the reproducibility and stability in the low-temperature polycrystallization process of silicon, the maximum bottleneck in the flat panel display manufacturing process can improve the productivity.

Claims (11)

Chamber; A heater installed in the chamber and having a substrate seated thereon; A counter electrode plate disposed on a plane above the heater; Linear drives installed at both sides of the chamber; A sputter gun linearly moved by the linear drive unit, The sputter gun The target surface has any inclination angle within a range of 0 ° to ± 90 ° from the direction toward the substrate; A cathode electrode coupled to the linear driver; A cathode electrode plate coupled to the cathode electrode and disposed in a direction facing the counter electrode plate; Metal catalyst doping apparatus for low temperature silicon crystallization comprising a. The method of claim 1, The sputter gun A metal catalyst doping apparatus for low temperature silicon crystallization, characterized in that the target surface is hinged to the linear drive so that the angle can be varied from the substrate direction. The method of claim 1, And the cathode electrode is a metal catalyst doping apparatus for low temperature silicon crystallization in which a cooling water passage is provided. The method of claim 1, The sputter gun Side surface of the cathode electrode plate, and the upper surface of the cathode electrode plate further comprises a shielding member disposed in the form of a metal catalyst doping apparatus for low temperature silicon crystallization. The method of claim 1, The sputter gun The metal catalyst doping apparatus for the low temperature crystallization of silicon of nickel or nickel alloy having a width within 10 ~ 50mm in the substrate transfer direction. Chamber; A heater installed in the chamber and having a substrate seated thereon; A counter electrode plate disposed in a plane on the heater; Linear drivers provided on both sides of the chamber; Using a metal catalyst doping apparatus for the low-temperature crystallization of silicon, the target surface has any one inclination angle in the range of 0 ° ~ ± 90 ° from the direction toward the substrate, including a sputter gun linearly moved by the linear drive unit In the doping method, The sputter gun is a doping method using a metal catalyst doping apparatus for low temperature silicon crystallization to move the moving speed within a moving speed of 1 to 6 m per minute and doping the metal catalyst. The method of claim 6, And the distance between the sputter gun and the counter electrode plate is within a range of 50-100 mm. The method of claim 6, The power applied to the sputter gun is a doping method using a metal catalyst doping apparatus for silicon low temperature crystallization having a condition of DC 300 ~ 1,000V, or 13.56MHz, 600W or 1.0 ~ 10KHz, 200 ~ 500W. The method of claim 6, A doping method using a metal catalyst doping apparatus for silicon low temperature crystallization to dope the metal catalyst in the flow rate of the gas injected into the chamber is 5 ~ 100 sccm range. The method of claim 6, Doping method using a metal catalyst doping apparatus for silicon low temperature crystallization to dope the metal catalyst in the state of the gas injected into the chamber is 5 X 10 ^-3 ~ 5 X 10 ^-1 Torr. The method according to any one of claims 6, 9, and 10, The gas injected into the chamber is any one of argon, neon, nitrogen, helium or a mixture of these gases doping method using a metal catalyst doping apparatus for low temperature silicon crystallization.

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