KR101087069B1 - Source gas supply method - Google Patents

Abstract

A source gas supply method in chemical vapor deposition is disclosed. Source gas supply method according to the invention comprises the steps of (a) heating the source material to generate a source gas; (b) measuring a partial pressure of the source gas before the source gas is introduced into the deposition chamber; And (c) when the value obtained by integrating the measured partial pressure of the source gas with respect to a predetermined time is smaller than a predetermined value, the source gas is introduced into the deposition chamber, and the measured source gas is And when the integral value of the partial pressure for a predetermined time is substantially equal to a predetermined value, preventing the source gas from flowing into the deposition chamber.

Chemical Vapor Deposition, Glass Substrate, Source Gas, Amorphous Silicon, Crystallization, Metal-Induced Crystallization (MIC), Partial Pressure, Integral

Description

Source For Supplying Source Gas

The present invention relates to a source gas supply method. More specifically, in the chemical vapor deposition method, a source gas capable of uniformly controlling the amount of source gas introduced into the deposition chamber by referring to the integral value of the partial pressure of the source gas introduced into the deposition chamber with respect to time. It relates to a supply method.

Chemical vapor deposition (CVD) is one of the representative methods for forming an active layer, an electrode layer, an insulating layer, and the like in the manufacture of a semiconductor or flat panel display together with physical vapor deposition (PVD).

In chemical vapor deposition, a source material corresponding to a raw material is heated to source gas, and then supplied into a chamber to form a desired film on a substrate. At this time, the substrate is heated to a predetermined temperature to supply energy necessary for forming a film.

On the other hand, as the substrate size of semiconductors and flat panel displays has become larger in recent years, supplying source gas uniformly over the entire surface of the substrate has emerged as a very important problem in chemical vapor deposition.

For example, in a thin film transistor (TFT) corresponding to a driving device of a liquid crystal display, metal catalyst particles are deposited on an amorphous silicon film during a process of manufacturing a polycrystalline silicon film by a metal induced crystallization (MIC) method. The chemical vapor deposition process for this is mentioned.

At this time, if the source gas (for example, metal organic compound gas) is not uniformly supplied over the entire surface of the liquid crystal display substrate, the concentration of the metal catalyst particles to be deposited varies according to the position of the substrate, resulting in final formation according to the substrate position. The grain size of the polycrystalline silicon film may vary. That is, the electrical properties (eg, electrical mobility, etc.) of the polycrystalline silicon film depend on the grain size. If the supply of the source gas (metal catalyst particles) is not uniform over the entire surface of the substrate as described above, the electrical properties of the thin film transistor may be reduced. Unevenness and this can be a more serious problem as the substrate size becomes larger.

In addition, when repeatedly performing the deposition process in order to mass-produce the substrate, if the supply amount of the source gas cannot be kept constant for each process, the deposition amount and deposition interval of the metal catalyst particles are different for each substrate produced in each process. May appear. In this case, the size and electrical properties of the crystal grains of the polycrystalline silicon film formed around the metal catalyst particles may be different for each process, thereby causing a problem of poor reproducibility between processes.

As a conventional technique for solving such a problem, a technique for maintaining a constant amount of source gas introduced into the chamber by maintaining a constant time for supplying a source gas has been introduced, but even if it is satisfactory level There was a limitation that it was difficult to obtain reproducibility between processes.

Therefore, the necessity of the development of the method which can form the polycrystalline silicon film which has a certain characteristic for every process by increasing the reproducibility between processes is increasing.

Accordingly, the present invention is to solve the problems of the prior art as described above, the partial pressure of the source gas introduced into the deposition chamber in the chemical vapor deposition method (Partial pressure) introduced into the deposition chamber with reference to the integral value with respect to time An object of the present invention is to provide a method capable of controlling the amount of source gas constantly.

In order to achieve the above object, a source gas supply method according to the present invention, a method for supplying a source gas in a chemical vapor deposition method, comprising the steps of: (a) heating the source material to generate a source gas; (b) measuring a partial pressure of the source gas before the source gas is introduced into the deposition chamber; And (c) when the value obtained by integrating the measured partial pressure of the source gas with respect to a predetermined time is smaller than a predetermined value, the source gas is introduced into the deposition chamber, and the measured source gas is And when the integral value of the partial pressure for a predetermined time is substantially equal to a predetermined value, preventing the source gas from flowing into the deposition chamber.

The predetermined time may be a time from when the source gas starts to flow into the deposition chamber to a time when the partial pressure of the source gas is finally measured.

The source gas may include Ni.

The step (a) may include supplying a carrier gas carrying the source gas together with the source gas.

The carrier gas may include Ar.

According to the present invention configured as described above, by controlling the amount of the source gas introduced into the deposition chamber with reference to the integral value of the partial pressure of the source gas flowing into the deposition chamber with respect to time, each process, In this case, the deposition amount and the deposition interval of the metal catalyst particles deposited on the substrate can be kept constant, and thus the size of crystal grains of the polycrystalline silicon film formed around the metal catalyst particles can be kept constant.

Furthermore, according to the present invention, since the reproducibility between the deposition processes can be improved, there is an effect that the electrical characteristics of the polycrystalline silicon film formed on the substrate can be kept constant for each step.

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

1 is a view showing the configuration of a source gas supply device 100 according to an embodiment of the present invention.

As illustrated, the source gas supply device 100 may include a deposition chamber 110, a pump 120, a source material evaporator 130, and a partial pressure analyzer 150.

In addition, the source gas supply device 100 may further include a carrier gas supply unit 140 to supply the source gas to the deposition chamber 110 smoothly.

In addition, the source gas supply device 100 may further include first to fifth valves V1 to V5 for controlling supply or flow of gas.

The deposition chamber 110 provides a space in which the glass substrate is loaded and a film forming process for the glass substrate is performed. The deposition chamber 110 may be provided with a heater (not shown) to supply energy necessary for forming a film to the substrate. Since the chemical vapor deposition process performed using the deposition chamber 110, the pump 120, and the source material evaporator 130 as a basic component is a well-known technology, a detailed description thereof will be omitted.

The pump 120 may be connected to the deposition chamber 110 so that gas may be easily discharged from the deposition chamber 110.

The source material 132 is stored in the source material evaporator 130 to generate a source gas supplied to the deposition chamber 110, and a heater 134 is installed around the source material evaporator 130 to provide a source. The source material 132 stored in the material evaporator 130 is vaporized to generate a source gas. The source material evaporator 130 is connected to the deposition chamber 110 by a predetermined connection pipe, and on the connection pipe, a second valve V2 for controlling gas supply from the source material evaporator 130 to the deposition chamber 110. ) Can be installed.

Carrier gas supply unit 140 is a predetermined carrier gas that serves to transport the source gas so that the source gas generated in the source material evaporation unit 130 can be smoothly delivered to the deposition chamber 110 and the pump 120 To supply. In general, since the source gas made of a metal element has a high specific gravity and low mobility, a separate carrier gas is required as a means for smoothly transferring the source gas. Here, the carrier gas should be light at the same time should not affect the deposition process, it is preferable that the specific gravity is low and low reactivity. For example, the carrier gas may include an inert gas such as argon (Ar), nitrogen (N ₂ ), and the like.

As described above, the heater 134 installed in the source material evaporator 130 may generate a source gas by vaporizing the source material 132, and the source gas generated as described above may be generated from the carrier gas supply unit 140. It may be introduced into the deposition chamber 110 with the carrier gas supplied. The source gas introduced into the deposition chamber 110 may be deposited on a substrate (not shown), and the deposition amount and the deposition amount of the source material deposited on the substrate according to the total amount of the source gas introduced into the deposition chamber 110. The spacing may appear different. The partial pressure analyzer 150 according to an embodiment of the present invention performs a function of controlling the total amount of source gas introduced into the deposition chamber 110. Hereinafter, the operating principle of the partial pressure analyzer 150 will be described. Let's look at it in detail.

The partial pressure analyzer 150 measures a partial pressure of the source gas among the gases introduced into the deposition chamber 110. Here, partial pressure means the pressure which each component gas shows when several gases are mixed. The partial pressure analyzer 150 may measure the partial pressure of the source gas included in the gas flowing into the deposition chamber 110 from the other gas (eg, the carrier gas). According to an embodiment of the present invention, the partial pressure analyzer 150 may include a residual gas analyzer (RGA) to measure the partial pressure of the source gas.

In addition, the partial pressure analyzer 150 may integrate the partial pressure of the source gas introduced into the deposition chamber 110 for a predetermined time for a predetermined time, and may be integrated into the deposition chamber 110 with reference to the integrated value. It decides whether to inject source gas. Here, the value obtained by integrating the partial pressure of the source gas with respect to the predetermined time may be utilized as a measure for measuring the total amount of the source gas introduced into the deposition chamber 110 for the predetermined time.

Specifically, the partial pressure analyzer 150 according to an embodiment of the present invention continues the partial pressure of the source gas introduced into the deposition chamber 110 from the time point at which the source gas starts to flow into the deposition chamber 110. After the point at which the integral value of the partial pressure of the source gas introduced into the deposition chamber 110 exceeds the predetermined value, no further source gas is introduced into the deposition chamber 110. Can be controlled. As a result, the partial pressure analyzer 150 may uniformly control the total amount of the source gas introduced into the deposition chamber 110 in one process. Meanwhile, the first valve V1 may open and close a moving passage of the source gas connected to the deposition chamber 110 under the control of the partial pressure analyzer 150.

As described above, according to the present invention, since the amount of source gas introduced into the deposition chamber 110 can be constantly controlled, the amount of source gas introduced in each process in the deposition process repeatedly performed in the mass production process. Can be kept constant. In this way, if the amount of source gas introduced in each process is kept constant, the deposition amount and the deposition interval of the metal catalyst particles deposited on the substrate in each process can be kept constant. The size of the crystal grains of the polycrystalline silicon film formed around the center can be kept constant. That is, according to the present invention, by improving the reproducibility between the deposition process, the electrical properties of the polycrystalline silicon film formed on the substrate can be maintained constant.

Example

Hereinafter, a process of controlling the amount of source gas introduced into the deposition chamber 110 will be described in detail with reference to the integral value of the partial pressure of the source gas according to an embodiment of the present invention.

In this embodiment, the metal catalyst particles were deposited on the amorphous silicon film by chemical vapor deposition to form a polycrystalline silicon film using the MIC method. In this embodiment, Ni was used as the metal catalyst particle for the MIC, and accordingly, the source material 132 used Ni (CP) ₂ powder. In addition, in the present embodiment, Ni (CP) ₂ powder is filled in the source material evaporator 130 and the heater 134 is operated to maintain the source material evaporator 130 at about 70 ° C. CP) ₂ gas was generated and then supplied into the deposition chamber 110. At this time, Ar was used as a carrier gas for smooth movement of Ni (CP) ₂ gas. Next, Ni catalyst particles were deposited on the amorphous silicon film by using Ni (CP) ₂ gas introduced into the deposition chamber 110, where the deposition temperature was set to about 130 ° C. Finally, the amorphous silicon film on which the Ni catalyst particles were deposited was subjected to crystallization heat treatment to prepare a polycrystalline silicon film. The heat treatment temperature was about 650 ° C., the heat treatment time was about 90 minutes, and the heat treatment atmosphere was an N ₂ gas atmosphere.

In the present embodiment, the same deposition process was performed three times in order to compare the experimental results between the processes.

2 is a graph illustrating a partial pressure of Ni (CP) ₂ gas flowing into the deposition chamber 110 according to an embodiment of the present invention over time. The graphs shown in black, red and blue in FIG. ₂ correspond to partial pressures of Ni (CP) ₂ gas measured in the primary, secondary and tertiary deposition processes, respectively. In order to obtain more reliable experimental results, it is revealed that the inflow patterns (instantaneous inflow amount, inflow time, etc.) of Ni (CP) ₂ gas were different for each deposition process.

3 is a graph showing an integral value of partial pressure of Ni (CP) ₂ gas flowing into the deposition chamber 110 according to an embodiment of the present invention over time. As in FIG. 2, the graphs shown in black, red and blue in FIG. 3 correspond to the primary, secondary and tertiary deposition processes, respectively. Mathematically, the value of the graph shown in FIG. 3 is a value obtained by integrating the value of the graph shown in FIG. 2 with respect to time, which corresponds to the area of the area enclosed by the graph and the time axis in FIG. .

As shown in FIGS. 2 and 3, the partial pressure analyzer 150 according to an embodiment of the present invention integrates the partial pressure of Ni (CP) ₂ gas introduced into the deposition chamber 110 with respect to time. continue until the value reaches the pre-set (predetermined) value to chamber 110 into the Ni (CP) of Ni (CP) ₂ gas to be determined so as to introduce the _second gas, and introduced into the deposition chamber 110 When the integral value of the partial pressure over time exceeds a predetermined value, it may be determined that no further Ni (CP) ₂ gas is introduced into the deposition chamber 110.

In the present Example, the predetermined value used as the reference | standard of the inflow of Ni (CP) ₂ gas was set to about 0.02torr * min. 2 and 3, in the first process, the partial pressure of the Ni (CP) ₂ gas introduced into the deposition chamber 110 is integrated into the deposition chamber 110 until the integrated value of 0.0194 torr · min is obtained. Ni (CP) ₂ gas is introduced (110 minutes to 115 minutes for about 5 minutes), and in the second process, the integral value of the partial pressure of Ni (CP) ₂ gas introduced into the deposition chamber 110 is obtained. Ni (CP) ₂ gas was introduced into the deposition chamber 110 until it became 0.01934torr · min (flowed for about 7 minutes from 108 minutes to 115 minutes), and the deposition chamber 110 in the third process. the Ni (CP) value by integrating the partial pressure of the _second gas flowing into the inlet was a Ni (CP) ₂ gas into the deposition chamber 110 until the 0.01955torr · min (about 8-102 minutes 110 minutes Inflows). For reference, as shown in FIG. 2, a low level partial pressure may be measured even before introducing Ni (CP) ₂ gas into the deposition chamber 110 (respectively of the primary, secondary and tertiary processes, respectively). Partial pressures in the intervals of about 110 minutes, about 108 minutes, and about 102 minutes), which is only random noise that can be measured in a practical experimental environment.

4 is a photograph showing the shape of grains of a polycrystalline silicon layer formed when Ni is deposited on an amorphous silicon layer and MIC is performed by supplying Ni (CP) ₂ into the deposition chamber 110 according to an embodiment of the present invention. to be. 5 is a photograph showing the shape of crystal grains of a polycrystalline silicon layer formed when Ni is deposited on an amorphous silicon layer and MIC is performed by supplying Ni (CP) ₂ for a predetermined time according to the related art.

Referring to FIG. 4, the grain size (G / S) of the polycrystalline silicon layer formed in the center portion of the substrate according to the exemplary embodiment of the present invention is in the first, second and third processes, respectively. As 14.0, 14.5, and 14.5, it can be seen that the grain size is almost the same for each process. In addition, referring to Figure 4, the size of the crystal grains of the polycrystalline silicon layer formed on the edge (edge) of the substrate according to an embodiment of the present invention is 14.9, 14.1 and 14.2 in the first, second and third processes, respectively It can be seen that the size of the crystal grains is constant in each process.

On the other hand, referring to Figure 5, the grain size (G / S) of the polycrystalline silicon layer formed in the center (center) of the substrate according to the prior art (G / S) is 15.4 in the primary, secondary and tertiary processes respectively , 18.3 and 27.0 show a large difference in grain size between the processes. In addition, referring to Figure 5, according to the prior art, the size of the crystal grains of the polycrystalline silicon layer formed on the edge of the substrate (15.6, 19 and 24.1 in the primary, secondary and tertiary processes, respectively, crystal grains between each process) It can be seen that the difference in size is significant.

Referring to the above experimental results, according to the present invention, the deposition amount and the deposition interval of the Ni catalyst particles deposited on the substrate are more evenly compared with the case of the conventional technique (that is, the technique of controlling the inflow time constantly). It can be seen that it can be controlled, so that the size of the crystal grains of the polycrystalline silicon layer formed around Ni can be more uniformly controlled. Therefore, according to the present invention, it can be said that the reproducibility between processes is also remarkably improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken in conjunction with the present invention. Variations and changes are possible. Such modifications and variations are intended to fall within the scope of the invention and the appended claims.

1 is a view showing the configuration of a source gas supply apparatus according to an embodiment of the present invention.

FIG. 2 is a graph illustrating a partial pressure of Ni (CP) ₂ gas flowing into a deposition chamber according to an embodiment of the present invention over time.

FIG. 3 is a graph showing an integral value of partial pressure of Ni (CP) ₂ gas flowing into a deposition chamber according to an embodiment of the present invention over time.

4 is a photograph showing a grain shape of a polycrystalline silicon layer formed when Ni is deposited on an amorphous silicon layer and MIC is performed by supplying Ni (CP) ₂ into the deposition chamber according to an embodiment of the present invention.

5 is a photograph showing a grain shape of a polycrystalline silicon layer formed when Ni is deposited on an amorphous silicon layer and MIC is performed by supplying Ni (CP) ₂ for a predetermined time according to the related art.

<Explanation of symbols for the main parts of the drawings>

100: source gas supply device

110: deposition chamber

120: pump

130: source material evaporation unit

140: carrier gas supply unit

150: partial pressure analysis unit

Claims (5)

A deposition chamber in which a film forming process is performed; A source material evaporator configured to generate a source gas stored in the source material and supplied to the deposition chamber; And a partial pressure analyzer configured to measure a partial pressure of the source gas among the gas flowing into the deposition chamber, wherein the source gas is supplied in a chemical vapor deposition method using a source gas supply device. (a) heating the source material to generate the source gas; (b) measuring a partial pressure of the source gas in the partial pressure analyzer before the source gas is introduced into the deposition chamber; And (c) a predetermined value is integrally determined by integrating the measured partial pressure of the source gas with respect to the time from when the source gas starts to flow into the deposition chamber to the time when the partial pressure of the source gas is finally measured. The source gas is introduced into the deposition chamber, and the source gas is introduced into the deposition chamber, and when the partial pressure of the measured source gas is integrated for a predetermined time, the source gas is substantially equal to a predetermined value. Preventing gas from entering the deposition chamber Method comprising a. delete The method of claim 1, And the source gas comprises Ni. The method of claim 1, The step (a) is characterized in that it comprises the step of supplying a carrier gas carrying the source gas with the source gas. 5. The method of claim 4, The carrier gas comprises Ar.

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