JP4004244B2 - Plasma processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma treatment how, in particular relates to a plasma treatment how that can be suitably applied when etching collectively multilayer film in a thin film circuit forming method of a thin film display industry.
[0002]
[Prior art]
In recent years, in the field of liquid crystal element manufacturing, there has been an increasing demand for a change to a manufacturing method that simplifies the process or a manufacturing method that has a low environmental load, from the viewpoint of manufacturing cost reduction and environmental protection. With the intensification of panel price competition and the trend toward larger panels, there is a demand for a method of performing dry etching on a laminated film uniformly and at a high speed from the conventional chemical etching method.
[0003]
However, the increase in the size of the glass substrate to be processed necessitates an increase in the size of the vacuum equipment including the dry etching apparatus, and the film quality of the thin film is very easy to change. The impurity concentration cannot be expected. Under such circumstances, user demand for dry etching performance is deepening. In order to etch a large substrate to be processed uniformly and at a high speed, a high-density plasma is produced from the RIE (reactive ion etching) method in which etching by ions can be performed by applying high-frequency power to the conventional lower electrode. Efforts have been made to develop an ICP (inductive couple plasma) method that generates and controls the bias with an independent high-frequency power source.
[0004]
Hereinafter, the configuration of such a typical dry etching apparatus will be described with reference to FIG. In FIG. 3, 21 is a vacuum container, 22 is an exhaust means for evacuating the inside of the vacuum container 21, and 23 is a gas supply means for supplying gas into the vacuum container 21, and the vacuum container 21 is maintained in a predetermined low pressure state. It is configured as follows. Reference numeral 24 denotes a first electrode disposed in the vacuum vessel 21 to which a first high frequency power supply 25 for applying high frequency power is connected. A substrate 26 to be processed is placed on the first electrode 24.
[0005]
Reference numeral 27 denotes a dielectric plate constituting the upper wall of the vacuum vessel 21, and reference numeral 28 denotes a second electrode wound on the coil disposed thereon, to which a second high frequency power supply 29 for applying high frequency power is connected. ing.
[0006]
The operation of the dry etching apparatus having the above configuration will be described. The substrate 26 such as a glass substrate is placed on the first electrode 24, and the gas supply means 23 etches the gas while the vacuum vessel 21 is exhausted by the exhaust means 22. When a constant high frequency power is applied to the first electrode 24 and the second electrode 28 from the first high frequency power supply 25 and the second high frequency power supply 29, the pressure inside the vacuum container 21 is adjusted. Plasma is generated and the substrate 26 is etched.
[0007]
At that time, ions, electrons, radicals, and the like are generated in the plasma and supplied to the substrate 26, and the thin film on the surface of the substrate 26 is etched. When the end of etching is detected, the operations of the first high frequency power supply 25 and the second high frequency power supply 29 are stopped, and the supply of the etching gas is stopped.
[0008]
[Problems to be solved by the invention]
However, when the substrate 26 is a large glass substrate of a liquid crystal element, as shown in FIG. 4, the thin film 33 formed on the substrate 26 has a large size and thus has a large amount of impurities and is very difficult to be etched. Yes. In FIG. 4, 30 is plasma, 31 is an etching seed, and 32 is a resist mask. In the case where the thin film 33 is a film that is etched by a chemical reaction with chlorine gas, as represented by an aluminum film, a natural oxide film layer 34 is formed on the surface, and the chemical reaction main process. It is still in a state where etching is difficult.
[0009]
Further, in such a thin film 33, in the case of a dry etching apparatus provided with two or more plasma generating means (first and second electrodes 24, 28) as described above, the timing of generating plasma is delicate. Due to the deviation, the reaction product 35 is deposited on the surface of the substrate 26 to form the etching stop layer 36, and there is a problem that the etching does not proceed.
[0010]
In view of the above-described conventional problems, and its object is to prevent deposition of reaction products on the substrate surface to provide a plasma processing how that can perform the processing such as etching reliably and efficiently.
[0011]
[Means for Solving the Problems]
In the plasma processing method of the present invention, the inside of a vacuum vessel is evacuated while introducing a gas to maintain a predetermined pressure state, a glass substrate is placed on a first electrode arranged in the vacuum vessel, In a plasma processing method of plasma processing a substrate with plasma generated by applying high frequency power to a second electrode consisting of a coil or an antenna provided outside the vacuum container separately from the first electrode, After applying high-frequency power to the first electrode during plasma processing, high-frequency power is applied to the second electrode to treat the substrate, and then the application of high-frequency power to the second electrode is stopped. The application of high frequency power to one electrode is stopped , and the reaction product is deposited on the substrate placed on the first electrode by previously applying high frequency power to the first electrode. Can prevent Reliably and efficiently be able to process such as etching with respect, also can finally prevent contamination by products to the substrate surface after treatment by stopping the application of RF power to the first electrode, the charge Great effect in preventing up-damage .
[0012]
Moreover, deposition of reaction products can be reliably prevented by supplying high-frequency power to the second electrode with a delay of 0.1 to 5 seconds after supplying high-frequency power to the first electrode.
[0013]
The high frequency power applied to the first electrode and the second electrode is 0.3 W / cm ² , respectively. 1.0 W / cm ² The above is preferable.
[0014]
The effect is particularly great when the plasma treatment is a batch etching of a multilayer film by etching.
[0017]
Alternatively, a plurality of second electrodes may be provided, and a high frequency power source may be provided for each.
[0018]
In addition, the effect is great when the substrate is a glass substrate on which a thin film transistor circuit is formed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a plasma processing how the present invention will be described with reference to FIGS.
[0020]
In FIG. 1, 1 is a vacuum vessel, 2 is an exhaust means for evacuating the inside of the vacuum vessel 1, 3 is a gas supply means for supplying gas into the vacuum vessel 1, and the vacuum vessel 1 is maintained in a predetermined low pressure state. It is configured as follows. Reference numeral 4 denotes a first electrode disposed in the vacuum vessel 1 to which a first high frequency power source 5 for applying high frequency power is connected. On the first electrode 4, a substrate 6 to be processed made of a glass substrate constituting a liquid crystal element is placed.
[0021]
Reference numeral 7 denotes a dielectric plate constituting the upper wall of the vacuum vessel 1, and 8 denotes a second electrode wound on the coil disposed thereon, to which a second high frequency power source 9 for applying high frequency power is connected. ing. The second electrode 8 serves as an ICP plasma source that generates inductively coupled plasma. Reference numeral 10 denotes power supply control means for controlling the operation timing of the first high-frequency power supply 5 and the second high-frequency power supply 9. After applying high-frequency power to the first electrode 4 by the first high-frequency power supply 5, 0 The high frequency power is applied to the second electrode 8 by the second high frequency power supply 9 with a delay of 1 second to 5 seconds.
[0022]
The operation of the dry etching apparatus having the above configuration will be described. As shown in FIG. 2, the substrate 6 of the present embodiment has a thin film 11 such as a metal wiring film formed on the surface of a glass substrate, and a mask pattern thereon. 12 is formed. Reference numeral 13 denotes a natural oxide film on the thin film 11. The substrate 6 is placed on the first electrode 4 in the vacuum vessel 1, and an etching gas in which Cl ₂ and BCl ₃ are mixed is introduced by the gas supply means 3 while the inside of the vacuum vessel 1 is exhausted by the exhaust means 2. The pressure is adjusted to a predetermined pressure of about 10 to 2 Pa. While maintaining this state, the first high frequency power source 5 is controlled by the power source control means 10 to apply a high frequency power of 0.3 W / cm ² or more to the first electrode 4, and then with a delay of 0.5 second. The second high frequency power source 9 is controlled to apply a high frequency power of 1.0 W / cm ² or more to the second electrode 8. As a result, plasma 14 is generated in the vacuum chamber 1, and the etching seed 15 collides with the thin film 11 such as a metal wiring film on the substrate 6 to be etched to form a metal wiring patterned with the mask pattern 12. When the end of etching is detected, the second high-frequency power supply 9 is stopped by the power supply control means 10, then the first high-frequency power supply 5 is stopped, and then the gas supply means 3 is stopped.
[0023]
In this way, by generating plasma from the first electrode 4, it is possible to prevent reaction products that inhibit etching from being deposited on the thin film 11 of the film to be etched, and to perform etching reliably and efficiently. Can do. In addition, by stopping the supply of high-frequency power to the first electrode 4 at the end, a great effect can be obtained in preventing contamination by the product on the thin film 11 to be processed and charge-up damage after etching.
[0024]
【The invention's effect】
According to the plasma treatment how the present invention, after the high-frequency power to the first electrode during plasma processing as described above, since so as to apply a high-frequency power to the second electrode, the first electrode The reaction product can be prevented from being deposited on the substrate placed thereon, and problems such as the etching stop state can be solved, and the substrate can be reliably and efficiently processed.
[0025]
Further, after stopping the application of RF power to the second electrode, since the end has been to stop the application of the high-frequency power to the first electrode, it can be prevented contamination with product to the substrate surface after treatment, Great effect in preventing charge-up damage.
[0026]
The substrate may or plasma treatment is a glass substrate effect is large etc. If a batch etching of the multilayer film by etching to form the thin film transistor circuitry.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment in which a plasma processing method of the present invention is applied to a dry etching apparatus.
FIG. 2 is an explanatory diagram of an action at the time of an etching process in the same embodiment.
FIG. 3 is a schematic configuration diagram of a conventional plasma processing apparatus.
FIG. 4 is an explanatory diagram of an action during an etching process in the conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Exhaust means 3 Gas supply means 4 1st electrode 5 1st high frequency power supply 6 Board | substrate 8 2nd electrode 9 2nd high frequency power supply 10 Power supply control means

Claims (4)

The inside of the vacuum vessel is evacuated while gas is introduced and maintained at a predetermined pressure state, a glass substrate is placed on the first electrode disposed in the vacuum vessel, the first electrode and the first electrode In a plasma processing method for plasma processing a substrate with plasma generated by applying high frequency power to a second electrode comprising a coil or an antenna provided outside a vacuum vessel , the first electrode is applied during plasma processing. After applying the high frequency power, the substrate is processed by applying the high frequency power to the second electrode, and then the application of the high frequency power to the second electrode is stopped, and finally the high frequency power is applied to the first electrode. The plasma processing method characterized by stopping .   2. The plasma processing method according to claim 1, wherein after the high frequency power is applied to the first electrode, the high frequency power is applied to the second electrode with a delay of 0.1 to 5 seconds. The high frequency power applied to the first electrode and the second electrode is 0.3 W / cm ² , respectively. 1.0 W / cm ² The plasma processing method according to claim 1 or 2, wherein the at least.   The plasma processing method according to claim 1, wherein the plasma processing is batch etching of a multilayer film by etching.

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