JP2000040694A - Dry etching device and dry etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inferiority such as the peeling of a resist, the wire breaking, etc., caused by abnormal discharge, by suppressing the accumulation of charge on an insulating substrate by a dry etching device. SOLUTION: In a dry etching device which is equipped with an He cooling mechanism for cooling a glass board 1 and a frame-shaped clamp 2 for pressing and fixing the periphery of the glass board all around from it upper side, the clamp 2 is inclined to be thicker from the inside periphery to outside periphery so that the flow of processing gas may be performed smoothly. It is more effective, the gentler the inclination of the clamp 2 is, but it is made about 30-50 deg. because there is necessity to make it have strength so that it may not be transformed even at a temperature of about 150 deg.. Furthermore, providing the periphery of the glass board with a plurality of grooves 6a and 6c in vertical direction can prevent the stay of gas at and around the glass board in the vicinity of the clamp 2 effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a dry etching apparatus and a dry etching method used in manufacturing a TFT array substrate constituting a TFT-LCD.
In particular, the present invention suppresses charge accumulation in a dry etching apparatus that occurs when a substrate on which a film to be processed is formed is an insulating substrate.

[0002]

2. Description of the Related Art In the manufacture of an active matrix type TFT array substrate constituting a TFT-LCD, an ITO film, a metal film such as Al, a film to be processed such as SiO ₂ formed on a glass substrate which is an insulating substrate. When dry etching is used, the resist is damaged by an increase in the substrate temperature, which causes problems such as an inconsistent pattern dimension and the inability to remove the resist. In order to avoid this, a method of spraying He gas from the back surface of the substrate to cool the substrate has been generally used. On the other hand, as a method of holding the substrate on the lower electrode plate, usually, a clamp that presses and fixes the peripheral portion of the substrate by about 2 to 3 mm from the upper side over the entire circumference is used. The material of the clamp needs to be strong enough not to be deformed by a temperature change or He pressure, and is generally made of ceramics or the same Al alloy as the chamber member.

[0003]

FIG. 8 is a schematic diagram showing a flow of a processing gas in a conventional dry etching apparatus. In the figure, 1 is a glass substrate which is an insulating substrate having a film to be processed on the surface, 3 is a lower electrode plate, 4 is a lower electrode,
Reference numeral 5 denotes an upper electrode, and reference numeral 22 denotes a conventional clamp. In the figure, arrows indicate the flow of a processing gas for etching. The conventional dry etching apparatus using the clamp 22 has a problem in that the exhaust of the etching processing gas blown out from the upper electrode 5 is obstructed by the clamp 22 and stays around the glass substrate 1. For this reason, there is a problem that the reaction product is re-adhered to the glass substrate 1 or electric charges are accumulated on the insulating glass substrate 1 and, when the conductive film is etched, discharge is generated between the patterns at the moment when the pattern is divided. A phenomenon that occurs or discharge occurs due to peeling charging at the moment when the glass substrate 1 is lifted with the pins from the lower electrode plate 3 has been remarkably observed in the periphery of the glass substrate 1. FIG. 9 is a diagram showing a resist pattern destroyed by abnormal discharge generated during etching of an ITO film in a conventional dry etching apparatus. Such abnormal discharge may cause peeling of the wiring material, melting of the underlying wiring material, and the like in addition to the resist peeling.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and suppresses the accumulation of electric charges on an insulating substrate in a dry etching apparatus, and prevents abnormal discharge or local plasma concentration. An object is to prevent defects such as peeling and disconnection.

[0005]

In a dry etching apparatus according to the present invention, an etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is provided, and a high frequency is applied between a pair of electrodes. A dry etching apparatus for performing etching on the substrate surface by ions and radicals generated in the plasma, comprising: a He cooling mechanism for cooling the substrate; It has a frame-shaped clamp for holding down and fixing, and the clamp has an inclined surface that becomes thicker from the inner peripheral portion toward the outer peripheral portion, and the inclined surface has a plurality of perpendicularly to the outer periphery of the substrate. A groove is provided. The inclination of the clamp is about 30 to 50 degrees.

In addition, an etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on the surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, and the lower side of the substrate. Is larger than the outer shape of the clamp.

In addition, an etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is placed, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, and the lower side of the substrate. The effective area (the size of the lower electrode plate) of the lower electrode located at the position (1) is smaller than the inner circumference of the clamp.

In addition, an etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is placed, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for performing etching on the substrate surface by radicals, comprising: a He cooling mechanism for cooling the substrate; and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference. On the side surface on the side, a blowing port for etching gas is provided.

Further, an etching gas is introduced into a vacuum atmosphere having a substrate having a film to be processed on its surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for performing etching on the substrate surface by radicals, wherein a supply port and an exhaust port for an etching gas are provided separately on the left and right sides of the substrate so that the etching gas flows in parallel to the substrate surface. Things.

Further, in the dry etching method according to the present invention, an etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is provided, and a high frequency is applied between a pair of electrodes to generate plasma. This is a dry etching method for performing etching on the substrate surface by ions and radicals generated in the plasma. The method includes a step of lowering or stopping the power of the application, that is, the RF discharge, flowing an etching gas or another gas, and then performing the RF discharge again in the original state to complete the etching.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a flow of a processing gas in the dry etching apparatus according to the first embodiment of the present invention. In the drawing, reference numeral 1 denotes an insulating glass substrate having a film to be processed on the surface in the process of manufacturing a TFT array substrate, and 2 denotes a frame-shaped clamp for pressing and fixing the peripheral portion of the glass substrate 1 from the upper side over the entire circumference. It has an inclined surface that becomes thicker from the peripheral portion to the outer peripheral portion, and a plurality of grooves are provided on the inclined surface in a direction perpendicular to the outer periphery of the substrate. Reference numeral 3 denotes a lower electrode plate, 4 denotes a lower electrode, and 5 denotes an upper electrode having an outlet for a processing gas for etching. In the figure, arrows indicate the flow of the processing gas. The dry etching apparatus according to the present embodiment introduces a processing gas for etching into a vacuum atmosphere in which a glass substrate 1 having a film to be processed on its surface is installed, and between a pair of electrodes, that is, between an upper electrode 5 and a lower electrode 4. Plasma is generated by applying a high frequency, and the surface of the glass substrate 1 is etched by ions and radicals generated in the plasma. A He cooling mechanism (not shown) for cooling the glass substrate 1 is provided. It is equipped.

In this embodiment, a plurality of grooves are provided on the inclined surface of the frame-shaped clamp 2 in a direction perpendicular to the outer periphery of the substrate.
The flow of the processing gas up to the exhaust was made smooth. The more the inclination of the clamp 2 is smaller, the more effective it is.
Since it is necessary to withstand the cooling pressure and to have strength so as not to be deformed even at a temperature of about 150 ° C., it is set to about 30 to 50 °. As shown in FIG. 2A, the shape of the groove is as follows.
On the glass substrate 1 side, a groove 6a formed substantially parallel to the substrate surface and connected internally to a groove 6b provided on the bottom surface of the clamp 2 in parallel with the outer periphery of the clamp 2, as shown in FIG. And a groove 6c wider than the groove 6a and formed to the outer periphery along the inclination of the clamp 2.

According to the present embodiment, by providing a plurality of grooves 6a and 6c on the inclined surface of the clamp 2, the glass substrate 1 near the clamp 2 can be maintained while maintaining the strength of the clamp 2.
It is possible to effectively prevent the processing gas from staying in the peripheral portion, and it is possible to suppress occurrence of abnormal discharge due to accumulation of electric charges in the peripheral portion of the glass substrate 1. As a result, it is possible to prevent the occurrence of defects such as resist peeling and disconnection in the dry etching process.

Embodiment 2 FIG. FIG. 3 is a perspective view showing the inside of the dry etching apparatus according to the second embodiment of the present invention. The outline of the configuration and functions of the dry etching apparatus according to the present embodiment is the same as that of the first embodiment,
In the drawings, the same or corresponding portions are denoted by the same reference characters and description thereof will be omitted. In the present embodiment, the lower electrode plate 3 and the lower electrode 4 located below the glass substrate 1 are larger than the outer shape of the clamp 2.

The operation of the dry etching apparatus according to the present embodiment will be described below. Conventionally, when a conductive film to be processed formed on the surface of an insulating glass substrate 1 is etched, when the conductive film is divided into patterns immediately before the end of the etching, the conductive film remains to the end due to uneven etching. In some cases, plasma was locally concentrated in the portion, abnormal discharge occurred, and pattern destruction and the like sometimes occurred. In order to prevent this, in the present embodiment, the lower electrode plate 3 and the lower electrode 4 are made larger than the outer shape of the clamp 2. As a result, the entire area of the lower electrode 4 does not become an insulator, so that local concentration of plasma can be relieved, and excessive concentration of electric charge in a portion that has not been completely patterned due to uneven etching can be avoided. It is.

Embodiment 3 FIG. 4 is a sectional view showing the inside of the dry etching apparatus according to the third embodiment of the present invention. In the figure, reference numeral 7 denotes an insulator provided around the lower electrode plate 3, which is arranged so as to cover the lower electrode plate 4 to the inside of a range that can be held down by the clamp 2. Note that the outline of the configuration and functions of the dry etching apparatus according to the present embodiment is the same as that of the above-described first embodiment, and the same and corresponding portions in the drawings are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, an insulator 7 is arranged around the lower electrode plate 3 located below the glass substrate 1, and the effective area of the lower electrode 4 is smaller than the inner circumference of the clamp 2. Here, the size of the lower electrode may be larger than that of the substrate but the same width as the electrode plate, and the periphery may be covered with an insulator. In addition,
In the present embodiment, the lower electrode 4 is larger than the glass substrate 1, but may have the same width as a portion of the lower electrode plate 3 that is not covered with the insulator 7, and the periphery may be covered with an insulator.

The operation of the dry etching apparatus according to this embodiment will be described below. By making the effective area of the lower electrode 4 smaller than the inner circumference of the clamp 2, the plasma density at the periphery of the glass substrate 1 near the clamp 2 where discharge is most likely to occur can be reduced, and abnormal discharge at the periphery of the glass substrate 1 can be achieved. Can be suppressed. As a result, abnormal discharge due to local concentration of plasma, which has conventionally occurred most in the periphery of the glass substrate 1, is reduced, and defects such as pattern destruction can be reduced.

Embodiment 4 FIG. 5 is a partial sectional view showing the inside of the dry etching apparatus according to the fourth embodiment of the present invention. In the figure, reference numeral 8 denotes a clamp elevating pin for raising and lowering the clamp 2, and reference numeral 9 denotes a blow-out port of an etching process gas provided on a side surface of the clamp 2 on the glass substrate 1 side. The outline of the configuration and functions of the dry etching apparatus according to the present embodiment is the same as that of the first embodiment,
In the drawings, the same or corresponding portions are denoted by the same reference characters and description thereof will be omitted.

In the dry etching apparatus according to the present embodiment, the processing gas for etching is supplied to the clamp 2 through the inside of the clamp elevating pin 8, and is supplied from the outlet 9 provided on the side surface of the clamp 2 on the glass substrate 1 side. It is configured to be blown out parallel to the substrate surface. The outlet 9 for the processing gas may be provided not only in the clamp 2 but also in the upper electrode 5. In the dry etching apparatus configured as described above, the processing gas does not stay in the peripheral portion of the glass substrate 1 in the vicinity of the clamp 2, the charge is prevented from being accumulated in the peripheral portion of the glass substrate 1, and the occurrence of abnormal discharge can be suppressed. . In the present embodiment, the clamp elevating pin 8 is used to supply the processing gas to the clamp 2. However, as another method, a method of supplying the gas from the upper electrode 5 side using a tube having elasticity, A pipe for supplying the processing gas may be separately provided.

Embodiment 5 FIG. 6 is a sectional view showing the inside of the dry etching apparatus according to the fifth embodiment of the present invention. In the figure, reference numerals 10 and 11 denote a supply port and an exhaust port of a processing gas for etching provided separately on the left and right sides of the glass substrate 1. Note that the outline of the configuration and functions of the dry etching apparatus according to the present embodiment is the same as that of the above-described first embodiment, and the same and corresponding portions in the drawings are denoted by the same reference numerals and description thereof is omitted.

In the dry etching apparatus according to the present embodiment, the supply port 10 and the exhaust port 11 of the etching processing gas are provided in the left and right processing chambers of the glass substrate 1, respectively.
The processing gas flows in parallel to the substrate surface. By configuring the processing gas to flow only in one direction, the number of locations where the processing gas stays is reduced. Also in the present embodiment, it is effective to make the inclination of the clamp 2 gentle. In the case where the processing gas flows in the lateral direction as in the present embodiment, the processing gas is not exhausted without being turned into plasma, and the sheath voltage is applied to the glass substrate 1 during the etching processing. There is no problem because it exists and the etching species almost perpendicularly enters the glass substrate 1. As described above, also in the present embodiment, the glass substrate 1 near the clamp 2
The processing gas does not stay in the peripheral portion, so that charges are prevented from being accumulated in the peripheral portion of the glass substrate 1, and occurrence of abnormal discharge can be suppressed.

Embodiment 6 FIG. Hereinafter, a dry etching method according to the sixth embodiment of the present invention will be described. Note that the outline of the configuration and functions of the dry etching apparatus used in the present embodiment is the same as that of the above-described first embodiment, and a description thereof will be omitted. In this embodiment, the etching of the film to be processed, for example, ITO progresses, and immediately before the pattern is divided, the power of the high frequency, that is, the power of the RF discharge is reduced or the discharge is stopped for a certain period of time to flow the etching gas or other gas. The charge accumulated on the glass substrate 1 is removed. Performing such an operation immediately before the pattern is divided is such that as the pattern is cut, a potential difference occurs between the patterns due to non-uniform plasma or the like, and discharge occurs between the divided patterns. It is to prevent.

FIG. 7 is a diagram showing a waveform of the emission intensity of indium during ITO etching. With the start of discharge, the emission intensity of indium increases and reaches a peak.
As the etching progresses and the ITO film disappears, the light emission intensity decreases, and when the etching is completed, the light emission intensity reaches a constant value indicated by A in the figure. The reason why the bottom of the waveform at the end is gentle is due to the distribution of the film thickness of the ITO film and the distribution of the etching rate. It can be said that it is time to start (near B in the figure). That is,
By monitoring the waveform of the emission intensity of indium, it is possible to reduce the power of the RF discharge or stop the discharge for a certain time immediately before pattern division. In particular,
Assuming that the emission intensity at the end of the etching is 0 and the emission intensity at the peak is 100, when the emission intensity reaches 95, the RF discharge is stopped for 5 seconds, and only the processing gas is flowed to remove electricity. Thereafter, the RF discharge is again performed in the original state to complete the etching. In the present embodiment, the processing gas is flowed as it is and used for static elimination, but other gases such as He may be flowed. Further, even if the power is reduced to about half without completely stopping the RF discharge, the effect of static elimination can be obtained. Also,
When the etching is completed, it is not always necessary to return the RF discharge to the original condition, and the etching may be completed under a low power state or another condition having a high selectivity with respect to the base film. It should be noted that Embodiments 1 to 6 described above can be used not only alone, but also by combining several methods to obtain higher effects.

[0024]

As described above, according to the present invention, there is provided a dry etching apparatus provided with a He cooling mechanism for cooling a substrate and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference. Since a plurality of grooves are provided on the inclined surface of the clamp in a direction perpendicular to the outer periphery of the substrate, the flow of the etching gas becomes smooth, and the gas does not stay around the substrate in the vicinity of the clamp. It is possible to suppress the occurrence of abnormal discharge due to the accumulation of electric charges, and to prevent the occurrence of defects such as resist peeling and disconnection in the dry etching step.

Further, by making the lower electrode located below the substrate larger than the outer shape of the clamp, or making the effective area of the lower electrode smaller than the inner circumference of the clamp,
It is possible to reduce abnormal discharge due to local concentration of plasma which is most likely to occur in the peripheral portion of the substrate near the clamp, and it is possible to reduce defects such as pattern destruction.

Further, by providing an etching gas blow-out port on the side of the clamp on the substrate side, or by providing an etching gas supply port and an exhaust port separately on the left and right sides of the substrate, the etching gas is supplied to the substrate surface. As a result, the gas is prevented from staying in the peripheral portion of the substrate near the clamp, and the occurrence of abnormal discharge due to the accumulation of electric charges in the peripheral portion of the substrate can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a flow of a processing gas in a dry etching apparatus according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a clamp of the dry etching apparatus according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing the inside of a dry etching apparatus according to a second embodiment of the present invention;

FIG. 4 is a sectional view showing the inside of a dry etching apparatus according to a third embodiment of the present invention;

FIG. 5 is a partial sectional view showing the inside of a dry etching apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing the inside of a dry etching apparatus according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a waveform of indium emission intensity during ITO etching.

FIG. 8 is a schematic diagram showing a flow of a processing gas in a conventional dry etching apparatus.

FIG. 9 is a view showing a resist pattern destroyed by abnormal discharge due to electric charge accumulated on a substrate in a conventional dry etching apparatus.

[Explanation of symbols]

1 glass substrate, 2, 22 clamp, 3 lower electrode plate, 4 lower electrode, 5 upper electrode, 6a, 6b, 6c
Grooves, 7 insulators, 8 clamp lifting pins, 9 gas outlets, 10 etching gas supply ports, 11 exhaust ports.

Claims (7)

[Claims] An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on its surface, a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, The clamp has an inclined surface that becomes thicker from an inner peripheral portion toward an outer peripheral portion, and a plurality of grooves are provided on the inclined surface in a direction perpendicular to the outer periphery of the substrate. Dry etching equipment. 2. The dry etching apparatus according to claim 1, wherein the inclination of the clamp is about 30 to 50 degrees. 3. An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on a surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, A dry etching apparatus wherein a lower electrode located below the substrate is larger than an outer shape of the clamp. 4. An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on its surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, A dry etching apparatus, wherein an effective area of a lower electrode located below the substrate is smaller than an inner circumference of the clamp. 5. An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on a surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for etching the substrate surface by radicals, comprising a He cooling mechanism for cooling the substrate, and a frame-shaped clamp for pressing and fixing the peripheral portion of the substrate from the upper side over the entire circumference, A dry etching apparatus, characterized in that an outlet for the etching gas is provided on a side surface of the clamp on the substrate side. 6. An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed is set on a surface, and a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching apparatus for performing etching on the substrate surface by radicals, wherein a supply port and an exhaust port for the etching gas are provided separately on the left and right sides of the substrate, and the etching gas is parallel to the substrate surface. A dry etching apparatus characterized in that the dry etching is performed. 7. An etching gas is introduced into a vacuum atmosphere in which a substrate having a film to be processed on its surface is installed, a high frequency is applied between a pair of electrodes to generate plasma, and ions generated in the plasma are generated. And a dry etching method for etching the substrate surface by radicals, wherein the etching of the film to be processed progresses, and immediately before the film to be processed is divided into patterns, the power of the RF discharge is reduced for a certain time or A dry etching method comprising a step of stopping the flow of the etching gas or another gas and thereafter completing the etching.