JP2001267303A - Plasma processor and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processor and a plasma processing method, which can perform uniform processing on a large substrate with a uniform plasma. SOLUTION: First and second electrodes 21 and 5 are arranged in a chamber 2, so that they counterpose each other. A substrate to be processed G is placed on the second electrode 5 and processing gas is introduced into the chamber 2, whose pressure is reduced. High frequency power is given to the upper electrode 21, and a plasma is formed. For performing a plasma processing on the substrate G, a substrate mount 10 on the lower electrode 5 is constituted, in such a way that the rectangular substrate whose long side is not less than 600 mm or the square substrate, whose one side is not led than 600 mm is installed and the frequency of high-frequency power is set to a range of 10 MHz to 13.56 MHz.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display (L).
The present invention relates to a plasma processing apparatus and a plasma processing method for performing plasma processing such as dry etching on a substrate to be processed such as a CD) substrate.

[0002]

2. Description of the Related Art For example, in an LCD manufacturing process, a glass LCD substrate as a substrate to be processed is
Etching, sputtering, CVD (chemical vapor deposition)
Etc. are frequently used.

Various types of plasma processing apparatuses have been used for performing such plasma processing, and among them, a capacitively coupled parallel plate plasma processing apparatus is mainly used.

A capacitively coupled parallel plate plasma processing apparatus is
A pair of parallel plate electrodes (upper and lower electrodes) are arranged in the chamber, a processing gas is introduced into the chamber, and a high frequency is applied to at least one of the electrodes to form a high-frequency electric field between the electrodes. To form a plasma of a processing gas to perform plasma processing on the substrate to be processed. In such a plasma processing apparatus, generally, the plasma generation high frequency is 13.56 MHz.
Alternatively, a frequency that is an integral multiple of the frequency is used.

[0005]

By the way, recently, LC
There is an increasing demand for a larger size D-substrate, and a very large substrate having a side of 1 m is being manufactured. As described above, as the size of the chamber increases with the size of the substrate to be processed, uniform plasma cannot be obtained,
The processing uniformity of the substrate to be processed also decreases.

The present invention has been made in view of the above circumstances, and provides a plasma processing apparatus and a plasma processing method capable of performing uniform processing with uniform plasma even on a large-sized substrate to be processed. With the goal.

[0007]

According to the present invention, there is provided a chamber for accommodating a substrate to be processed,
First and second electrodes provided so as to face each other in a chamber, a high-frequency power supply for supplying high-frequency power to the first electrode, and exhaust means for maintaining the inside of the chamber at a predetermined reduced pressure; A processing gas introduction unit that introduces a processing gas into the chamber, a plasma processing apparatus that converts the processing gas into plasma with the high-frequency power and performs plasma processing on the substrate mounted on the substrate mounting unit. The second electrode is grounded and has a long side of 6
A substrate to be processed having a rectangular shape of 00 mm or more or a square having a side of 600 mm or more is placed, and the frequency of the high-frequency power supplied from the high-frequency power source is 10 MHz.
Provided is a plasma processing apparatus, which is not less than z and less than 13.56 MHz.

Further, the present invention provides a method in which a first electrode and a second electrode are provided in a chamber in parallel with each other, the second electrode is grounded, and a substrate to be processed is mounted on the second electrode. A high-frequency power is supplied to the first electrode while introducing a processing gas into a chamber maintained under reduced pressure, a high-frequency electric field is formed between the electrodes to generate a plasma of the processing gas, and the plasma is applied to the first electrode. A plasma processing method for performing a predetermined plasma processing on a processing substrate, wherein the processing target substrate is a rectangle having a long side of 600 mm or more or a side of 600 mm or more.
The present invention provides a plasma processing method characterized in that the frequency of the supplied high-frequency power is 10 MHz or more and less than 13.56 MHz in the case of the above square.

The inventors of the present invention have studied to enable uniform plasma processing even for a large-sized substrate having a rectangular shape having a long side of 600 mm or more or a square having a side of 600 mm or more. As a result, as shown in FIG. 1, the minimum value of V _PP is present in relation to the peak-to-peak value V _PP of the high-frequency voltage in the vacuum in the chamber and (pressure) electrode, when the substrate size is increased V _PP Is shifted to the high vacuum side (low pressure side). It is empirically known that the plasma density becomes uniform near the minimum value of the minimum value of V _PP . Therefore, if the degree of vacuum (pressure) in the chamber is set to the high vacuum side (low pressure side) to the vicinity of the minimum value of V _PP , the disadvantage that the cathode electrode is sputtered and the plasma density decreases are caused. After further investigation to avoid such inconvenience,
The frequency of the supplied high frequency power is 13.56 MHz
It has been found that when the frequency is set lower than that, the minimum value of V _PP can be shifted to a lower vacuum side (higher pressure side). Therefore, even with a large substrate as described above, without causing the disadvantage that the cathode electrode is sputtered and the disadvantage that the plasma density is reduced,
Plasma processing can be performed near the minimum value of V _PP .
Therefore, uniform processing can be performed by uniform plasma. However, if the frequency is lower than 10 MHz, the plasma density itself decreases, so that the frequency is higher than 10 MHz.

[0010] In the RIE mode in which high-frequency power is applied to the second electrode on which the object to be processed is placed, the above-mentioned inconvenience is not seen because the action of ions in the plasma is mainly involved.
Therefore, the present invention is applied to the case of the PE mode in which high-frequency power is applied to the first electrode on which no object is placed.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a sectional view schematically showing a plasma processing apparatus for an LCD substrate according to one embodiment of the present invention, and FIG. 3 is a plan view showing a susceptor (lower electrode) of the plasma processing apparatus. The plasma processing apparatus 1 is configured as a capacitively-coupled parallel plate etching apparatus in which electrode plates are vertically opposed to each other and a power supply for plasma formation is connected to an upper electrode.

The plasma processing apparatus 1 has a chamber 2 formed in the shape of a rectangular tube made of, for example, aluminum whose surface is anodized (anodized), and the chamber 2 is grounded. A prismatic susceptor support 4 is provided at the bottom of the chamber 2, and a susceptor 5 for mounting an LCD substrate G as a substrate to be processed is provided on the susceptor support 4. Have been. This susceptor 5 functions as a lower electrode (second electrode) and is grounded.

A refrigerant chamber 7 is provided inside the susceptor support 4. In the refrigerant chamber 7, a refrigerant is introduced through a refrigerant introduction pipe 8, discharged from a refrigerant discharge pipe 9, and circulated. Then, the cold heat is transferred to the substrate G via the susceptor 5, whereby the processing surface of the wafer W is controlled to a desired temperature.

The susceptor 5 is shaped like a prism similarly to the susceptor support 4. The upper central portion of the susceptor 5 is a convex portion, and the substrate G is placed on the upper surface of the convex portion. The protruding portion has substantially the same size as the substrate G to be placed, and as shown in FIG.
It has a rectangular shape of m or more. Therefore, the configuration is such that a substrate having a long side of 600 mm or more is placed. In addition, the length of one side of the convex portion of the susceptor 5 is 600 m.
m or more, and in that case, a square having a side length of 600 mm or more is placed. Also,
As shown in FIG. 3, four lift pins 14 protrude from the susceptor 5, and the transfer of the substrate G is performed with the lift pins 14 protruding.

At the periphery of the upper end of the susceptor 5, a substrate G
A frame-shaped focus ring 16 is arranged so as to surround. The focus ring 16 is made of an insulating material such as ceramic.

An upper electrode 21 is provided above the susceptor 5 so as to face the susceptor 5 in parallel. The upper electrode 21 is connected to the chamber 2 via an insulating material 25.
And an electrode plate 23 having a surface facing the susceptor 5 and having a large number of discharge holes 24, and a conductive material that supports the electrode plate 23, such as aluminum whose surface is anodized. And an electrode support 22 made of the same, and constitutes a shower head. The susceptor 5 as the lower electrode and the upper electrode 21 are, for example, 3
They are separated by about 0 to 300 mm.

The electrode support 22 of the upper electrode 21
Is provided with a gas inlet 26, and a gas supply pipe 27 is connected to the gas inlet 26. The gas supply pipe 27 is connected to a processing gas via a valve 28 and a mass flow controller 29. A source 30 is connected. A processing gas for etching, which is plasma processing, is supplied from a processing gas supply source 30.

An exhaust pipe 31 is connected to the bottom of the chamber 2, and an exhaust device 35 is connected to the exhaust pipe 31. The evacuation device 35 is provided with a vacuum pump such as a turbo-molecular pump, so that the inside of the chamber 2 can be evacuated to a predetermined reduced-pressure atmosphere. A gate valve 32 is provided on the side wall of the chamber 2.
The substrate G is conveyed to and from an adjacent load lock chamber (not shown) with the gate valve 32 opened.

A high-frequency power supply 40 is connected to the upper electrode 21 via a matching device 41. At this time, power is supplied by a power supply rod 33 connected to the center of the upper surface of the upper electrode 21. The high frequency power supply 40 has a frequency of 10 MHz or more and 13.5.
A frequency in a range of less than 6 MHz is applied, and a uniform plasma process can be performed by applying a high frequency power in a frequency in this range.

Next, the processing operation in the plasma processing apparatus 1 will be described by taking as an example the case where the amorphous silicon film formed on the substrate G is etched.

First, the substrate G to be processed is carried into the chamber 2 from a load lock chamber (not shown) after the gate valve 32 is opened, and is placed on the susceptor 5. In this case, the transfer of the substrate G is performed by a lifter pin 14 that is inserted through the inside of the susceptor 5 and protrudes from the susceptor 5. Next, gate valve 3
2 is closed, and the inside of the chamber 2 is evacuated to a predetermined degree of vacuum by the exhaust device 35.

Thereafter, the valve 28 is opened and the processing gas is supplied from the processing gas supply source 30 to the mass flow controller 2.
9, while the flow rate is adjusted, the processing gas supply pipe 2
7. The gas is introduced into the upper electrode 21 through the gas inlet 26 and further discharged through the discharge hole 24 of the electrode plate 23 to the substrate G as shown by the arrow in FIG. The pressure in 2 is maintained at a predetermined value.

Then, a high-frequency power is applied to the upper electrode 21 from the high-frequency power source 40, and thereby a high-frequency electric field is generated between the upper electrode 21 and the susceptor 5 as a lower electrode, and the processing gas is dissociated into plasma, An etching process is performed.

In this case, when the frequency of the applied high frequency power is 13.56 MHz or an integer multiple thereof as in the conventional case, if the pressure in the chamber is made the same as in the conventional case,
A rectangle with a long side of 600 mm or more or a side of 600 mm
With the large-sized substrate having the square shape described above, it is difficult to make the plasma uniform over the entire substrate G, and the plasma tends to be non-uniform. This is because, as described above, when the size of the substrate increases, the minimum value of V _PP , which is known to have a uniform plasma density in the vicinity thereof, shifts to the high vacuum side (low pressure side).

If the degree of vacuum (pressure) in the chamber is set to a high degree of vacuum (low pressure) by an amount corresponding to the shift of the minimum value of V _PP , there is a disadvantage that the electrode plate 23 of the upper electrode 21 functioning as a cathode electrode is sputtered. . Therefore, in order to avoid such inconvenience that the electrode plate 23 is sputtered and to ensure the uniformity of the plasma, in the present embodiment, the frequency of the high-frequency power applied from the high-frequency power supply 40 to the upper electrode 21 is 10 MHz or more. .56 MHz or less.
By setting the frequency to less than 13.56 MHz, the minimum value of V _PP can be shifted to a higher voltage side, which causes a disadvantage that the electrode plate 23 of the upper electrode 21 serving as the cathode electrode is sputtered. Without, V
Plasma processing can be performed near the peak of _PP . Therefore, uniform processing can be performed by uniform plasma. However, if the frequency is less than 10 MHz, the plasma density itself decreases and the processing efficiency decreases.
0 MHz or more.

In the case of the PE mode in which high-frequency power is applied to the upper electrode 21 on which no substrate is mounted as in the present embodiment, the pressure in the chamber 2 must be 13. It is preferably at least 3 Pa. The upper limit of the pressure in the chamber is set within a range in which normal plasma processing can be performed, and is, for example, about 300 Pa.

Next, an experiment for confirming the effect of the present invention will be described. 680mm x 680mm square LCD
An etching experiment was performed on the substrate using the apparatus shown in FIG. The high frequency power supplied from the high frequency power supply is 24
00W and the frequency is 13.56 MHz, 12.0
MHz and 10.0 MHz. Note that a mixed gas of SF ₆ , HCl, and He was used as the processing gas, and the pressure in the chamber was set to 30 Pa.

As a result, at 13.56 MHz, the etch rate in the center is high and the average etch rate is 16
The uniformity was ± 24% at 5.4 nm / min. However, the etch rate in the peripheral part tended to increase as the frequency was lowered. In the case of 12.0 MHz, 242.3 n was used.
m / min, ± 11%, 10 MHz, 240.
2 nm / min, ± 16%, and the frequency is 13.5
It has been confirmed that by setting the frequency to less than 6 MHz, the uniformity of etching is improved and the etch rate is increased.

The present invention can be variously modified without being limited to the above embodiment. For example, in the above embodiment, the case where the present invention is applied to an etching apparatus has been described.
The present invention can be applied to other plasma processing apparatuses such as CVD film formation.

[0030]

As described above, according to the present invention,
The frequency of the high-frequency power supplied to the electrode is 10 MHz or more1
By setting it to less than 3.56 MHz, the long side is 600 m
In plasma processing of a large substrate having a rectangular shape of m or more or a square shape having a side of 600 mm or more, plasma can be made uniform and uniform plasma processing can be performed.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the degree of vacuum (pressure) in a chamber and V _PP .

FIG. 2 is a cross-sectional view schematically showing a plasma processing apparatus for an LCD substrate according to an embodiment of the present invention.

FIG. 3 is a plan view showing a susceptor (lower electrode) of the plasma processing apparatus of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Plasma processing apparatus (etching apparatus) 2: Chamber 5; Susceptor (second electrode) 21; Upper electrode (first electrode) 30; Processing gas supply source 35; Exhaust apparatus 40;

Continuation of the front page F term (reference) 4G075 AA24 AA30 BC02 BC04 BC06 BD14 CA47 EB42 EC10 FC13 5F004 AA01 AA16 BA04 BB11 BB15 DA18 DA22 DA29 DB01 5F045 AA08 AF11 BB02 CA15 DQ10 EB08 EB09 EF05 EH04 EH05 EM05E14

Claims (5)

[Claims] A chamber accommodating a substrate to be processed, first and second electrodes provided to face each other in the chamber, a high-frequency power supply for supplying high-frequency power to the first electrode, An exhaust unit that maintains the inside of the chamber at a predetermined reduced pressure state; and a processing gas introduction unit that introduces a processing gas into the chamber. A plasma processing apparatus for performing plasma processing on a mounted substrate, wherein the second electrode is grounded, and a long side thereof is 600 mm
The above-described rectangular or square substrate having a side of 600 mm or more is configured to be mounted thereon, and the frequency of the high-frequency power supplied from the high-frequency power source is 1
A plasma processing apparatus characterized by being at least 0 MHz and less than 13.56 MHz. 2. The plasma processing apparatus according to claim 1, wherein the frequency of the high-frequency power supplied from the high-frequency power supply is 12 MHz. 3. A first electrode and a second electrode are provided in a chamber in parallel with each other, the second electrode is grounded, and a substrate to be processed is placed on the second electrode under reduced pressure. A high-frequency power is supplied to the first electrode while introducing a processing gas into the held chamber, and a high-frequency electric field is formed between the electrodes to generate a plasma of the processing gas. A plasma processing method for performing the plasma processing described above, wherein the frequency of the high-frequency power to be supplied is 10 MHz or more and less than 13.56 MHz when the substrate to be processed is a rectangle having a long side of 600 mm or more or a square having a side of 600 mm or more. A plasma processing method characterized by the above-mentioned. 4. The frequency of the supplied high frequency power is 12 MHz.
The plasma processing method according to claim 3, wherein z is set to z. 5. The pressure in the chamber is 13.3P.
5. The method according to claim 3, wherein the distance is not less than a.
4. The plasma processing method according to 1.