JP2005264226A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device by which a substrate such as a glass substrate having a thermal conductivity lower than that of a silicon substrate is subjected to uniform plasma treatment, by accurately measuring the temperature distribution of the substrate during plasma treatment and further, uniformly keeping the substrate at the target temperature based on the measured result. <P>SOLUTION: The plasma treatment device 10 comprises: a mounting stand 16 for mounting the substrate to be plasma-treated; and a substrate elevating/lowering apparatus 22 with a plurality of supporting pins 40 of freely projecting to the mounting face of the mounting stand 16 from the mounting face, supporting a substrate 17 from the side of the mounting stand 16 and elevating/lowering. Each supporting pin 40 is a cylindrical member, and a temperature detecting means for detecting the temperature of the substrate is arranged in a space of the cylindrical member. During process treatment where the supporting pins 40 are stored into arrangement holes 44 provided at the mounting stand 16, the temperature distribution of the substrate 17 mounted on the mounting stand is measured from the side opposite to the plasma treatment face in the substrate 17. Using the measured result, control is performed in such a manner that the temperature distribution is made uniform. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is a plasma processing apparatus that processes a substrate or the like using plasma (etching, thin film formation), accurately measures the temperature distribution of the substrate during the plasma processing, and controls the substrate temperature of the substrate during the plasma processing. The present invention relates to a plasma processing apparatus.

  In semiconductor processing of large scale integrated circuits (LSIs) and flat panel displays (flat panel displays, FDP), plasma processing using a plasma processing apparatus is often used to etch a substrate or form a thin film on a substrate. It has been. In plasma processing, a processing process that uniformly etches the substrate or forms a thin film uniformly on the substrate is desired, and it is desired to uniformly form plasma that has a great influence on the processing process.

In Patent Document 1 below, a temperature sensor is installed in a chamber in which a wafer is processed, the temperature in the chamber is measured, and this is used for feedback control of the temperature in the chamber to keep the temperature in the chamber uniform. Manufacturing methods have been proposed.
However, when the temperature in the chamber is made uniform by temperature measurement in Patent Document 1, the substrate temperature during plasma processing is not necessarily controlled accurately, and etching and thin film formation are not necessarily performed uniformly. was there. In particular, it is a serious problem in a glass substrate having a thermal conductivity lower than that of a silicon substrate. Further, when a glass substrate that is extremely large compared to the size of the silicon substrate is a plasma processing target, this problem is great.

On the other hand, in Patent Document 2 below, in order to continuously monitor the substrate temperature of a semiconductor wafer during plasma processing, an optical temperature sensor or an optical / optical temperature that includes an optical fiber in a gap provided in one of the wafer lift pins. It has been proposed to control a substrate temperature by embedding a sensor and continuously measuring a temporal change in the temperature of the substrate.
However, in Patent Document 2, since the temperature of the semiconductor wafer is measured at one location and used as the substrate temperature of the semiconductor wafer, the glass has a large substrate size and lower thermal conductivity than the semiconductor wafer (silicon substrate). The substrate temperature of the substrate or the like cannot be accurately controlled to perform uniform processing on the substrate.

Patent Document 3 below proposes a manufacturing method using a semiconductor manufacturing apparatus that measures the temperature at a desired position, such as a substrate to be processed, by moving the pointing direction of a temperature measuring apparatus for measuring the temperature in the furnace. Patent Document 4 below proposes a method for measuring the temperature of a measurement object from the intensity of radiated light from the measurement object substrate in plasma.
Even if an attempt is made to measure the temperature of the substrate to be processed by moving the pointing direction of the temperature measuring device as in the temperature measurement of Patent Document 3, the temperature cannot be accurately measured due to the influence of the deposit layer deposited on the surface of the substrate. . In addition, the measurement range is limited for large substrates. When measuring the temperature of an object to be measured from the intensity of radiated light from a substrate to be measured in plasma as in Patent Document 3, the radiated light is measured from the chamber through the temperature measuring window. Accurate temperature cannot be measured due to deposits.

  As described above, the conventional technique has a problem that uniform plasma treatment cannot be performed on a substrate having a low thermal conductivity and a large size.

JP 59-48931 A JP 2001-358121 A Japanese Patent Laid-Open No. 9-24360 JP-A-4-116433

  Therefore, in order to solve the problems of the prior art, the present invention accurately measures the temperature distribution of the substrate during plasma processing for a substrate having a low thermal conductivity, such as a glass substrate, as compared with a silicon substrate. An object of the present invention is to provide a plasma processing apparatus for uniformly performing plasma processing by uniformly holding a substrate at a target temperature based on a measurement result.

  In order to achieve the above object, the present invention is a plasma processing apparatus for performing plasma processing on a substrate having a thermal conductivity of 50 (W / m / K) or less, and generates plasma using a supplied gas. A plasma generating means, an electrode for performing plasma processing, a mounting table on which a substrate to be plasma-processed is mounted, and a substrate that protrudes freely from the mounting surface of the mounting table and supports the substrate from the mounting table side. A substrate lifting / lowering means having a plurality of substrate support pins that move up and down, and each of the substrate support pins is a cylindrical member having a gap inside, and the substrate temperature is detected in the gap of the cylindrical member. A temperature detection unit is provided, and the substrate support pin is stored in the placement hole provided in the mounting table, and the substrate is mounted on the mounting table using the temperature detection unit from the side opposite to the plasma processing surface of the substrate. Placed board To provide a plasma processing apparatus characterized by measuring the degree distribution.

  At that time, the mounting table is provided with cooling / heating means for cooling / heating the substrate corresponding to each of the substrate support pins, and an area corresponding to the arrangement position of the substrate support pins is defined by the cooling / heating means. It is preferable to have a control device for controlling the temperature separately.

Further, the ratio of the area (mm ² ) of the plasma processing surface to the substrate thickness (mm) of the substrate to be subjected to the plasma processing is preferably 80000 (mm) or more.

The present invention has a built-in temperature detection means in each of a plurality of substrate support pins that protrude freely with respect to the mounting surface of the substrate having a lower thermal conductivity than the silicon substrate and support the substrate from the mounting table side, Measure the temperature distribution of the substrate. For this reason, the temperature distribution of the substrate during the plasma processing can be obtained accurately. Therefore, the temperature of the substrate can be uniformly controlled using this temperature distribution, and the plasma treatment can be performed uniformly.
For example, when performing the etching process, the etching rate increases as the substrate temperature increases. Therefore, when the uniform temperature distribution is not maintained, the etching amount is different and uniform etching processing cannot be performed. In particular, in a large-sized substrate having a low thermal conductivity such as an FPD glass substrate, the non-uniform temperature distribution on the substrate processing surface is a major obstacle to uniform plasma processing. When forming a uniform thin film on this large substrate or performing a uniform etching process, it is particularly effective to maintain and control the temperature distribution of the substrate uniformly.

  Hereinafter, the plasma processing apparatus of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a diagram schematically showing a cross section of a plasma processing apparatus (hereinafter referred to as an apparatus) 10 which is an embodiment of the plasma processing apparatus of the present invention.
The apparatus 10 is a parallel plate type processing apparatus that performs plasma processing on a substrate having a thermal conductivity of 50 (W / m / K) or less, preferably 5 (W / m / K) or less. Examples of such a substrate include an FPD glass substrate and a resin substrate.

  The apparatus 10 mainly includes a chamber (processing chamber) 12, a high-frequency electrode 14, a mounting table 16, a lower electrode 18, a gas supply port 20, a substrate plate lifting mechanism 22, a heating / cooling driving device 24, a control device 26, and a vacuum exhaust device 27. It has mainly.

The chamber 12 is a decompression vessel that introduces a reaction gas and generates and holds plasma.
The high-frequency electrode 14 is an electrode provided in the upper part in the chamber 12 and is disposed so as to face the lower electrode 18. The high frequency electrode 14 is connected to a high frequency power supply 30 via a matching box 28.

The mounting table 16 is a portion for mounting and holding the substrate 17 to be plasma-processed, and a rectangular lower electrode 18 is provided on the upper surface of the mounting table 16. A high-frequency power source 34 is provided at the lower portion of the mounting table 16 and is connected to the lower electrode 18 through a matching box 32. The reason why the shape of the lower electrode 48 is rectangular is that, for example, a rectangular large glass substrate such as a flat panel display is used as the substrate 17 to be plasma-processed.
The gas supply port 20 is a part that supplies the reaction gas to the chamber 12 and is connected to the reactive gas supply device 33. In addition, the chamber 12 has an exhaust port (not shown), and is connected to the vacuum exhaust device 27 to exhaust the reaction gas in the chamber 12 during processing and reduce the pressure to a predetermined atmospheric pressure.

A reactive gas such as silane (SiH ₄ ) or fluorocarbon is introduced into the chamber 12 together with, for example, argon gas, and high-frequency power is applied to the high-frequency electrode 14 and the lower electrode 18 under a predetermined application condition in a reduced-pressure atmosphere. A plasma fluid composed of radicals and ions of gas components is generated, and a plasma treatment is performed on the substrate 17 placed on the mounting table 16.

The substrate lifting mechanism 21 is connected to a plurality of support pins 40 that support the substrate 17 conveyed from the outside of the chamber 12 for plasma processing from below, a support arm 42 that lifts and lowers the support pins 40, and the support arm 42. And a drive device 42 for freely raising and lowering the support pin 40.
The support pin 40 is arranged in a support pin arrangement hole 44 drilled in the lower electrode 18 and the mounting table 16, and the arrangement hole 44 is freely moved upward and downward by driving of the drive device 42. The substrate 17 is configured to move up and down freely.
That is, when the substrate 17 is transported above the mounting table 16 in the chamber 12 by a transport robot (not shown), the support pin 40 protrudes from the lower electrode 18 to support the substrate 17 and transport (not shown). The substrate 17 received from the robot is lowered while supporting the substrate 17 while supporting the substrate 17, and is placed on the upper surface of the lower electrode 18.

FIG. 2 is a view of an example of the arrangement of the support pins 40 that support the substrate 17 as viewed from above in the chamber 12 in FIG.
The support pins 40 are provided at six locations evenly distributed on the surface of the lower electrode 17. By providing in this way, the large substrate 17 can be stably supported. In particular, since the glass substrate used for the FPD has a large substrate area and a large weight with respect to the thickness of the substrate, the support pins 40 are uniformly distributed so as to support the substrate 17 stably.
Each of the support pins 40 distributed in this way is a cylindrical member having a gap inside, and a temperature detection sensor 50 is provided in the gap inside the cylindrical member as shown in FIG. Yes.

  The temperature detection sensor 50 is a device that detects the substrate temperature, and examples thereof include a fluorescent optical fiber thermometer and a thermocouple temperature sensor. The fluorescence type optical fiber thermometer is provided with a temperature measuring temperature sensing unit equipped with a fluorescent material at the tip of the optical fiber, and irradiates the fluorescent material at the tip with the light incident from the other end to reduce the relaxation time of the emitted fluorescence. By measuring, the temperature of the fiber tip is measured. A temperature sensing part having such a fluorescent material of the temperature detection sensor is provided flush with the tip of the support pin 40. Thus, the substrate temperature can be known by measuring the relaxation time of the fluorescence emitted by the fluorescent material that is in contact with the substrate 17 and the temperature of the substrate and having the same temperature as the substrate temperature. In other words, the support pin 40 is provided with a temperature sensing unit including a fluorescent material, and a temperature detection sensor is configured. Fluorescence emitted from the temperature sensing unit is generated by irradiation of a laser beam emitted from a semiconductor laser element (not shown) incorporated in the control device 26 through an optical fiber passing through the support pin 40, and this fluorescence is transmitted through the optical fiber. Thus, it is configured to be guided to a temperature calculation unit (not shown) incorporated in the control device 26. The temperature calculation unit includes a photodetector that receives fluorescence and an arithmetic unit. Such fluorescent optical fiber thermometers are well known and will not be described.

  The temperature sensing part of the temperature detection sensor 50 is provided so as to be flush with the tip of the support pin 40, and the substrate 17 and the temperature sensing part are in contact with each other. However, in the present invention, the temperature sensing part is not necessarily provided flush with the substrate. It is not necessary for 17 and a temperature sensing part to contact. Even if the substrate 17 and the temperature sensing unit are not in contact with each other, the temperature information obtained by the temperature sensing unit may be corrected by the temperature calculation unit of the control device 26 to calculate the substrate temperature. it can.

  The temperature detection sensor 50 may be a thermocouple. In this case, the thermocouple's temperature sensing part is provided flush with the tip of the support pin 40 as in the case of the fluorescent optical fiber thermometer. As a result, the substrate 17 and the temperature sensing unit come into contact with each other, and the detection signal having the same temperature as the substrate temperature is guided to a temperature calculation unit (not shown) incorporated in the control device 26 via a signal line passing through the support pins 40. Configured to be. The temperature calculation unit is configured to calculate the substrate temperature from the detection signal using an arithmetic device. Such thermocouple thermometers are well known and will not be described.

  In addition, although the temperature sensing part of the temperature detection sensor 50 is built in the support pin 40 and the temperature calculation part is built in the control device 26, in the present invention, the temperature calculation part is built in the support pin 40. It may be.

On the other hand, the mounting table 16 is provided with heating / cooling means (not shown) for adjusting the temperature of the substrate 17 during the process, corresponding to the arrangement positions of the support pins 40. That is, the area of the mounting table 16 is made into a block corresponding to the arrangement position of the support pins 40, and different cooling / heating means are provided for each block.
The cooling / heating means is exemplified by a configuration in which a flow path is provided inside the mounting table 16 and the cooling medium and the heating medium circulate. Alternatively, a flow path for circulating the cooling medium can be used as the cooling means, and a heating element (heater) that generates heat by flowing an electric current through the resistor can also be used as the heating means.
The temperature adjustment of the cooling / heating means is performed by the heating / cooling driving device 24. The heating / cooling driving device 24 is connected to the control device 26, and the cooling and heating temperature of the cooling / heating means are controlled by a control signal supplied from the control device 26.

The control device 26 obtains the temperature distribution by obtaining the substrate temperature of each of the six support pins 40 from the fluorescence information sent from the six support pins 40 via the optical fiber, and these temperature distributions are uniform. It is a part for generating a control signal so as to be uniform when it is determined whether or not it is held uniformly. That is, the control device 26 determines the temperature distribution of the substrate 17 mounted on the mounting table 16 from the side opposite to the plasma processing surface of the substrate 17 using the temperature detection sensor, and according to the arrangement position of the support pins 40. The temperature is controlled separately by the cooling and heating means.
The apparatus 10 is configured as described above.

In the apparatus 10, the temperature of the substrate 17 is measured by measuring the substrate temperature from the side opposite to the substrate processing surface during the process using the temperature detection sensors incorporated in all of the support pins 40 that support the substrate 17 as described above. Therefore, the temperature of the substrate 17 during the plasma processing can be uniformly controlled using this temperature distribution. In particular, a substrate in which the ratio of the area (mm ² ) of the plasma processing surface to the substrate thickness (mm) of the substrate subjected to plasma processing is 80000 (mm) or more, for example, the size is 200 mm × 200 mm × 0.5 mm (vertical, horizontal) In the case of a substrate of (height), the temperature distribution in the substrate thickness direction is small enough to be ignored compared to the temperature distribution of the processing surface of the substrate 17. For this reason, even if the substrate temperature is measured from the side opposite to the substrate processing surface, the accurate temperature can be measured.
Further, since the temperature detection sensor is disposed in the arrangement hole 44 provided in the mounting table 16, the temperature detection sensor is not affected by deposits shielded by the substrate 17 and deposited during the plasma processing during the plasma processing. For this reason, the substrate temperature during plasma processing can be measured accurately.

As described above, in the apparatus 10, after the substrate 17 is transferred to the support pins 40 protruding from the surface of the lower electrode 18 by a transfer robot (not shown), the substrate 17 is moved to the surface of the lower electrode 18 by the lowering of the support pins 40. Placed.
Thereafter, the reaction gas is introduced into the chamber 12 in a reduced pressure state, power is applied to the high-frequency electrode 14 and the lower electrode 18 under predetermined conditions, plasma is generated from the reaction gas, and this plasma acts on the substrate 17. Then, plasma processing is performed.
At that time, the temperature distribution of the substrate 17 is measured using the temperature detection sensor 50 from the side opposite to the plasma processing surface of the substrate 17 in a state where the support pins 40 are stored in the arrangement holes 44 provided in the mounting table 16. .

The measured temperature distribution is determined by the control device 26 to determine whether the temperature distribution is uniform. If it is determined that the temperature distribution is not uniform, the temperature adjustment in the region corresponding to the position where the support pin 40 to be adjusted is heated. This is performed by the cooling drive unit 24.
Thus, by uniformly controlling the temperature distribution on the substrate processing surface, the plasma processing can be performed uniformly.

  The plasma processing apparatus of the present invention has been described in detail above. However, the present invention is not limited to the above embodiment, and various modifications and changes may be made without departing from the spirit of the present invention. is there.

It is the figure which showed typically the cross section of the plasma processing apparatus which is one Embodiment of the plasma processing apparatus of this invention. It is the figure which showed arrangement | positioning of the support pin used for the plasma processing apparatus shown in FIG. It is the figure explaining the surroundings of the support pin of the plasma processing apparatus shown in FIG. 1 in detail.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plasma processing apparatus 12 Chamber 14 High frequency electrode 16 Mounting base 18 Lower electrode 20 Gas supply port 22 Substrate board raising / lowering mechanism 24 Heating / cooling drive apparatus 26 Control apparatus 27 Evacuation apparatus 28, 32 Matching box 30, 34 High frequency power supply 40 Support pin 44 Arrangement hole 50 Temperature sensor

Claims (3)

A plasma processing apparatus for performing plasma processing on a substrate having a thermal conductivity of 50 (W / m / K) or less,
Plasma generating means for generating plasma using the supplied gas;
An electrode for performing plasma treatment, and a mounting table on which a substrate to be plasma-treated is placed;
A substrate lifting means comprising a plurality of substrate support pins that freely protrude from the mounting surface of the mounting table and support the substrate from the mounting table side to move up and down;
Each of the substrate support pins is a cylindrical member having a gap inside, and is provided with temperature detecting means for detecting a substrate temperature in the gap of the cylindrical member, and the substrate is provided in the arrangement hole provided in the mounting table. A plasma processing apparatus for measuring a temperature distribution of a substrate placed on the mounting table from the side opposite to the plasma processing surface of the substrate using the temperature detecting means during the process processing in which the support pins are stored. .   The mounting table is provided with cooling / heating means for cooling / heating the substrate corresponding to each of the substrate support pins, and an area corresponding to the arrangement position of the substrate support pins is separately heated by the cooling / heating means. The plasma processing apparatus according to claim 1, further comprising a control device to be controlled. The plasma processing apparatus according to claim 1, wherein a ratio of an area (mm ² ) of the plasma processing surface to a substrate thickness (mm) of the substrate subjected to the plasma processing is 80000 (mm) or more.

Images