JP2000332088A - Electrostatic chuck with destaticizing function and destaticization method of the electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure charge amount left on a substrate, know the exact destaticized amount and surely eliminate charges from a substrate by arranging a destaticizing arm mounted to move on an electrostatic attraction stage. SOLUTION: The potential of a substrate 16 is raised through plasma discharge by a high frequency power supply 19. After a prescribed treatment time is elapsed, the high frequency power supply 19 is turned off and then an electrostatic chuck 13 is turned off successively. Thereafter, treated gas inside a vacuum chamber 10 is exhausted, and a destaticizing arm 14 is moved on an electrostatic attraction stage 11. The arm 14 comes into contact with the edge part of the substrate 16 on the stage 11 and eliminates the charges, and destaticized amount of the substrate 16 is detected by a measuring mechanism part 15. If destaticization is not sufficient, furthermore negative charge is forcibly applied to the arm 14 and charges left in the substrate 16 is eliminated rapidly. Since charges are thereby eliminated exactly from a substrate, a substrate will not jump up and down and misregistration, etc., will not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck used in a processing apparatus for performing various types of plasma processing on a wafer in a semiconductor device manufacturing process, and more particularly, to removing residual charges from a substrate or the like on the electrostatic chuck. The present invention relates to an electrostatic chuck with a static elimination function.

[0002]

2. Description of the Related Art Generally, an electrostatic chuck is used for fixing a semiconductor wafer to a counter electrode when performing various kinds of plasma processing on the wafer in a semiconductor device manufacturing process. However, when the semiconductor wafer is attracted to the electrostatic chuck many times by repeatedly performing the plasma processing,
Electric charges remain on the insulator surface of the electrostatic chuck or on the semiconductor wafer itself, and the wafer cannot be removed smoothly from the electrostatic chuck.

[0003]

Specifically, there is a disadvantage that the semiconductor wafer swings or jumps on the lift pins at the moment of removal. If the semiconductor wafer jumps on the lift mechanism in this way, the position of the wafer is not determined, causing a transfer failure, and a stable operation cannot be performed. Therefore, for the purpose of removing residual charges, for example, a vacuum chamber, which is a processing chamber, is opened to the atmosphere to collect substrates and remove products adhering to the tips of lift pins, causing loss in production. I was As described above, in the case of a transport error caused by poor static elimination, it is necessary to polish each contact at the tip of the lift pin in order to enhance the conduction effect of the ground line. Therefore, the work process has to be stopped for the polishing operation, resulting in a time loss.

For example, Japanese Patent Application Laid-Open No. 8-83832 discloses that a power supply and a static elimination can be switched without providing a changeover switch on a moving body having an electrostatic chuck, thereby preventing dust from the moving body. There has been disclosed a power supply device for preventing charge accumulation on the surface of an electrostatic chuck. However, according to the technology disclosed herein, power supply and static elimination can be performed without providing a changeover switch on the moving body, so that the changeover switch can be removed from the moving body and dust generation from the moving body can be prevented. .

For example, Japanese Patent Application Laid-Open No. 9-64021 discloses an electrostatic chuck in which a residual charge accumulated on the surface of an insulator of an electrostatic chuck is discharged by discharging the residual charge to and from the back surface of the wafer. Have been. According to this technique, after performing a plasma treatment, a gas is introduced into the processing chamber to evacuate the processing chamber to a vacuum of 0.5 to 3 Torr, and then the residual charges are removed by discharging. Therefore, unlike the present invention, the residual charge of the substrate is not measured, and the charge is not effectively removed accordingly.

Accordingly, an object of the present invention is to provide an electrostatic chuck with a static elimination function that can accurately measure the amount of residual charge on a substrate and accurately grasp the amount of static elimination to reliably eliminate static from the substrate. It is in.

[0007]

In order to solve the above-mentioned problems, the present invention basically employs the following configuration. That is, the first aspect according to the present invention is:
An electrostatic chuck including an electrostatic chuck stage and a lift mechanism arranged in a vacuum chamber, wherein an electrostatic elimination arm movably mounted on the electrostatic chuck stage is provided. In a second aspect according to the present invention, a loading step of loading a substrate onto an electrostatic suction stage, and a filling step of filling a processing gas into a vacuum chamber,
An adsorption step of adsorbing the substrate on the electrostatic adsorption stage, an application step of applying a high frequency to the substrate in the vacuum chamber, and an adsorption step of adsorbing the substrate after the application step of applying the high frequency are completed. A discharging step of discharging the processing gas from the chamber, a measuring step of measuring a charge on the substrate on the electrostatic chuck stage, and an application of applying a discharging voltage from the discharging arm to the substrate according to the measurement result of the measuring step. A static elimination method for an electrostatic chuck, comprising a step.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrostatic chuck with a static elimination function according to the present invention comprises an electrostatic chuck stage and a lift mechanism arranged in a vacuum chamber in order to solve the above-mentioned problems in the prior art. In the provided electrostatic chuck, the static elimination arm movably mounted on the electrostatic chuck stage is disposed, so that the residual charges on the substrate can be accurately eliminated.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an electrostatic chuck with a charge eliminating function according to the present invention. That is, FIG. 1 is a cross-sectional view showing an electrostatic chuck with a static elimination function according to an embodiment of the present invention. Here, the electrostatic chuck with a static elimination function is movable on the electrostatic chuck stage 11 in an electrostatic chuck 13 having an electrostatic chuck stage 11 and a lift mechanism 12 arranged in a vacuum chamber 10. The mounted static elimination arm 14 is provided.

The static elimination arm 14 is movable and retractable in a direction perpendicular to the plane of FIG. 1 and is connected to a measuring mechanism 15 disposed outside the vacuum chamber 10. Also,
The static elimination arm 14 has a tapered contact arm 14a which is expanded upward at both ends so that static electricity can be eliminated by contacting the thin portion of the insulating film layer of the substrate 16, that is, the edge 16a of the substrate 16.
It has.

One end of the measuring mechanism 15 has a charge removing arm 14.
And the other end is grounded. Further, the measuring mechanism 15 is also connected to the electrostatic suction stage 11. The amount of charge on the substrate 16 can be detected by the measuring mechanism 15.

A counter electrode 17 is disposed at an upper end of the vacuum chamber 10 facing the electrostatic chuck stage 11, and performs a plasma discharge. Further, the electrostatic suction stage 11 is connected to a high frequency power supply 19 via a matching circuit 18.

The lift mechanism 12 includes an electrostatic suction stage 11
Lift pin 20 and lift pin 20 projecting from the projection hole of
And a drive rod 22 and the like for urging in the direction of retracting. Therefore, by raising the drive rod 22, the lift pins 20 can be projected from the projected holes of the electrostatic suction stage 11.

Next, a description will be given of a method for removing static electricity from the electrostatic chuck using the electrostatic chuck having a charge eliminating function of the present invention configured as described above. First, the substrate 16 is loaded on the electrostatic suction stage 11 in a loading step. At this time, the static elimination arm 1
Numeral 4 retreats laterally from the electrostatic suction stage 11.

Next, in a gas filling step, the vacuum chamber 10 is filled.
The inside is filled with the processing gas. As processing gas, dry
In the case of etching, CF is used in oxide film etching._Four, C
HF ₃, C₄F₈Etc. are used. Also, silicon edge
In the ching, Cl₂, HBr, SF₆Etc. are used.

In the adsorption step, the substrate 16 is electrostatically adsorbed on the electrostatic adsorption stage 11. When the adsorption step of electrostatically adsorbing the substrate 16 to the electrostatic chuck 13 is repeated, residual charges are generated on the electrostatic adsorption stage 11 and the substrate 16. Also,
In the application step, a high-frequency power supply 19 is applied to the substrate 16 in the vacuum chamber 10 via the matching circuit 18.

Next, in the discharge step of discharging the processing gas, the suction step of sucking the substrate is finished after the application step of applying the high frequency, and the processing gas is further discharged from the vacuum chamber 10. In the measurement step, the charge on the substrate 16 on the electrostatic suction stage 11 is measured. this,
In accordance with the measurement result of the measurement process, the substrate 1
A static elimination voltage is applied to 6.

In this manner, the residual charges can be accurately removed from the substrate 16, so that the substrate 16 does not jump when being lifted by the lift mechanism 12.

FIG. 2 is a time chart showing an embodiment of the present invention. The operation of the electrostatic chuck with a static elimination function of the present invention will be described with reference to this time chart. First, a processing gas is supplied into the vacuum chamber 10, and then the substrate 16 carried in is electrostatically adsorbed on the electrostatic adsorption stage 11.

Next, the potential of the substrate 16 rises due to the plasma discharge by the high frequency power supply 19. After a lapse of a predetermined processing time, the high-frequency power supply 19 is turned off. Subsequently, after the electrostatic chuck 13 is turned off, the vacuum chamber 10
The processing gas inside is discharged. After the processing gas is exhausted,
The static elimination arm 14 is moved onto the electrostatic suction stage 11.

The arm 14 contacts the edge of the substrate 16 on the electrostatic attraction stage 11 to remove electricity. At this time, the substrate 1
6 is detected by the measurement mechanism unit 15, and if the neutralization state is insufficient, a negative charge is further forcibly applied to the neutralization arm 1.
4 is applied. Thus, charges remaining on the substrate 16 can be quickly eliminated.

As described above, according to the electrostatic chuck with a charge removing function of the present invention, the charge can be accurately removed from the substrate, so that the substrate does not jump. Further, even when the substrate is transported while being gripped by the arm, no displacement or the like occurs.

The present invention is not limited to the above-described embodiment, and various design changes can be made based on the technical concept of the present invention.

[0024]

According to the present invention, since the above-described technical configuration is employed, the semiconductor wafer does not swing or jump on the lift pins. In addition, the position of the wafer is stable, and there is no possibility of causing a transfer failure, and stable operation is possible. The reason is that the residual charge remaining charged on the semiconductor wafer is forcibly removed by the discharging arm.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an electrostatic chuck with a charge removing function according to an embodiment of the present invention.

FIG. 2 is a time chart showing one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum chamber 11 Electrostatic adsorption stage 12 Lift mechanism 13 Electrostatic chuck 14 Static elimination arm 15 Measurement mechanism part 16 Substrate 16a Edge part 17 Counter electrode 18 Matching circuit 19 High frequency power supply 20 Lift pin 21 Coil spring

Claims (8)

[Claims] 1. An electrostatic chuck having an electrostatic chucking stage and a lift mechanism arranged in a vacuum chamber, wherein an electrostatic elimination arm movably mounted on the electrostatic chucking stage is provided. Characteristic electrostatic chuck with static elimination function. 2. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm is movable in a horizontal direction. 3. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm contacts the thin portion of the insulating film layer of the substrate to eliminate static. 4. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm contacts the edge of the substrate to eliminate static. 5. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm includes a measuring mechanism for measuring a charge amount of the substrate. 6. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm detects and analyzes the charge amount of the substrate by a measuring mechanism and controls the static elimination operation according to the result. 7. The electrostatic chuck with a static elimination function according to claim 1, wherein the static elimination arm detects and analyzes the charge amount of the substrate by a measurement mechanism and applies a negative charge according to the result. . 8. A loading step of loading a substrate onto an electrostatic suction stage, a filling step of filling a processing gas into a vacuum chamber, a suction step of sucking a substrate onto the electrostatic suction stage, An application step of applying a high frequency, an adsorption step of adsorbing the substrate after the application step of applying the high frequency is completed, and a discharge step of discharging a processing gas from the vacuum chamber; and a substrate on the electrostatic suction stage. A charge removing step for measuring an electrostatic charge on the substrate, and an applying step of applying a charge removing voltage from the charge removing arm to the substrate according to a measurement result of the measuring step.