JPH08115901A - Plasma processing method and plasma processor - Google Patents

Abstract

PURPOSE: To stabilize the start of plasma by introducing inert gas into a processing container and producing plasma precedently by means of an induction means, and introducing processing gas for an object to be processed into the processing container, and producing plasma by means of the induction means. CONSTITUTION: Inert gas such as Ar or the like is introduced from a shower head 19 arranged opposite to an object 2 to be processed. The pressure inside a container 1 is set to be specified pressure, for example 1⊗10<-2> Torr by the control of an exhaust means 17 and a valve 15. Next, plasma is produced for several seconds within a processing container where high frequency voltage, for example, 13.56MHz is applied by a high frequency power source 31. By producing plasma precedently by inert gas in this way, the plasma of the gas to process the objected to be processed can be started and stabilized easily, so the processing of the object 1 for processing by plasma can be stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method and a plasma processing apparatus.

[0002]

2. Description of the Related Art A semiconductor wafer provided in an airtight processing container or a substrate on which a thin film transistor for a liquid crystal display is formed is subjected to a film forming process or an etching process by plasma treatment. Plasma treatment for forming a semiconductor element is performed in a semiconductor manufacturing process, and in particular, as a plasma source for the induction means,
For example, a technique of generating a plasma in a processing container by applying a high frequency to a coil is disclosed in JP-A-2-235332, "Plasma processing apparatus", and JP-A-3-79025, "Plasma-coupled planar plasma. And a method and apparatus for processing this plasma article ",
JP-A-4-290428, "Plasma Reactor Using UHF / VHF Resonant Antenna Supply Source and Method Therefor", and JP-A-5-206072, "Plasma Processing Apparatus Using Inductive RF Coupling and Method Thereof". There is.

In a plasma processing apparatus for generating a plasma by applying a high frequency voltage to these induction means, 1 × 10 ⁻³
Of course, plasma can be easily generated in the pressure region of Torr to several Torr, but 1 × lower than this pressure region.
At a vacuum pressure of 10 ⁻³ Torr or less, it is difficult to satisfactorily generate plasma. Therefore, when introducing the processing gas for processing the object to be processed, the pressure inside the processing container is once n × 10 ⁻ , for example. ^The pressure is set to a relatively high pressure of ² Torr (1 ≦ n ≦ 9, n is an integer), and after the plasma is generated, the pressure is evacuated to a predetermined value of a lower pressure, for example, n × 10.
There has been known a method of performing plasma processing on an object to be processed under the pressure of n × 10 ⁻³ Torr by lowering the pressure to ⁻³ Torr (1 ≦ n ≦ 9, n is an integer).

However, in this conventional method, the pressure is changed in the state where the plasma of the processing gas is generated until the plasma is stabilized by introducing the processing gas. However, there is a problem to be solved in that the processing result varies depending on the object to be processed and lacks stability.

Further, the plasma processing apparatus using the induction means is characterized in that the vacuum pressure range in which plasma can be generated is wide ranging from several Torr to 1 × 10 ⁻⁶ Torr. On the other hand, plasma can be generated relatively easily when a high frequency is applied to a parallel plate electrode used as a plasma source of a plasma processing apparatus used in an etching process or a CVD process in a semiconductor manufacturing process. Vacuum pressure range is several Torr
To 1 × 10 ⁻² Torr, and 1 × 10 ⁻³ To
It has been difficult to generate and process plasma in a low vacuum pressure region of rr or less.

As semiconductor elements formed on a semiconductor wafer are highly integrated, for example, a memory chip is 16 MDRAM.
To 64M DRAM, 256M DRAM and the design rule is further miniaturized from 5.0μ to 2.5μ, the lower vacuum pressure by the plasma processing device, for example, 1 ×
It has become necessary to perform fine processing by performing plasma processing under a vacuum pressure condition of 10 ^-2 Torr to 1 × 10 ^-6 Torr.

This means that by making the vacuum pressure lower, the mean free path of electrons is extended, and the vertical component of the ions or active species in the plasma drawn into the object to be processed is more effective. Therefore, a plasma processing apparatus that enables plasma processing to increase the speed of the etching process in the depth direction compared to the etching process in the entrance direction of the contact hole when forming the contact hole using the etching process is required. Because it has been done.

Therefore, such a lower vacuum pressure,
As a more specific pressure region, there is a demand for a plasma device that applies a high frequency to the induction means as a plasma source that generates plasma at 1 × 10 ⁻² Torr to 1 × 10 ⁻⁶ Torr.

[0009]

However, in the region of lower vacuum pressure mentioned above, it is necessary to ignite and stabilize the plasma at a higher vacuum pressure, for example, several To.
It is difficult as compared with the range of rr to 1 × 10 ^-2 Torr, and in particular, the stabilization of the plasma at the time of start-up when the processing gas for processing the object to be processed is turned into plasma greatly affects the processing result of the object. If the plasma startup time of the unstable processing gas is long, the problem that the processing result differs for each object to be processed or the problem that the in-plane uniformity within the same object to be processed is lost occurs. Was required.

An object of the present invention is to provide a plasma processing method and a plasma processing apparatus for processing an object to be processed with plasma generated by applying a high frequency voltage to the induction means, and a method and apparatus for stabilizing the rise of plasma. To provide.

[0011]

According to a first aspect of the present invention, an object to be processed provided in an airtight processing container is generated by plasma generated by applying high frequency to induction means provided in the processing container. In the plasma generating method for processing, a first step of introducing an inert gas into the processing container to generate plasma by the guiding means, and a processing gas for processing the object to be processed are introduced into the processing container. And a second step in which plasma is generated by the inducing means to process the object to be processed. The invention according to claim 2 is characterized in that the inert gas and the processing gas are provided by a dielectric shower head provided inside the processing container and facing the object to be processed. The invention of claim 3 is characterized in that the pressure in the processing container in the second step is lower than the pressure in the processing container in the first step. Claim 4
In the second step, the introduction of the processing gas is performed after the pressure in the processing container is set to a predetermined pressure. According to a fifth aspect of the present invention, the first step of loading and placing the object to be processed in an airtight processing container, and introducing an inert gas into the processing container to evacuate the target to achieve a predetermined pressure. A second step of forming an inert gas atmosphere, a third step of applying a high frequency to an induction means to generate plasma in the processing container, and then stopping the introduction of the inert gas, and the processing container A fourth step of introducing a processing gas into the processing means, applying a high frequency to the induction means to convert the processing gas into plasma, and processing the object to be processed;
Is provided. In the invention of claim 6, the inert gas is Ar (argon), Xe (xenon), K
r (krypton), He (helium) or N ₂ (nitrogen)
Gas, and the predetermined pressure is 1 × 10 ⁻³ To
rr to 1 × 10 ⁻¹ Torr, and the inducing means is a coil. According to a seventh aspect of the invention, the pressure in the processing container in the fourth step is 1 × 10 when the processing gas is introduced into the processing container to generate plasma.
^-6 Torr to 1 × 10 ^-2 Torr. According to the invention of claim 8, a first step of loading and placing the object to be processed in an airtight processing container, and introducing an inert gas into the processing container to evacuate the object to achieve a predetermined pressure. Second step of forming an inert gas atmosphere, a third step of applying a high frequency to the induction means to generate plasma in the processing container, and processing while continuing to generate the plasma in the processing container A fourth step of treating the object to be treated by introducing gas and converting the treatment gas into plasma. In the invention of claim 9, the inert gas introduced in the second step is Ar (argon), Xe (xenon), Kr (krypton), He.
(Helium) or N ₂ (nitrogen) gas,
The predetermined pressure is 1 × 10 ^-3 Torr to 1 × 10 ^-1 T
orr. The invention of claim 10 is
After the processing gas is turned into plasma in the fourth step, the introduction of the inert gas into the processing container is stopped. According to the invention of claim 11, an airtight processing container in which an object to be processed is placed, an induction means for generating plasma of an inert gas introduced into the processing container, and a processing gas in the processing container. A plasma processing apparatus, comprising: a processing gas introducing unit for introducing the processing gas; and the processing unit converts the processing gas into plasma to process the object to be processed. According to a twelfth aspect of the present invention, an airtight processing container in which the carried-in target object is placed, and the inside of the processing container are evacuated to an inert gas atmosphere of a predetermined pressure by the introduced inert gas. Exhaust means, induction means for generating plasma of the inert gas, and processing gas introduction means for introducing a processing gas into the processing container, and in the processing container at a predetermined pressure by the exhaust means, A plasma processing apparatus, wherein the processing gas is turned into plasma by an inducing means to process the object to be processed. According to a thirteenth aspect of the present invention, an airtight processing container in which the carried-in target object is placed, an inducing means for generating plasma of the inert gas introduced into the processing container, and the plasma are generated. A plasma processing apparatus, further comprising: a processing gas introducing unit for introducing a processing gas into the processing container, wherein the object to be processed is processed by the processing gas plasmatized by the guiding unit.

[0012]

According to the plasma processing method or the plasma processing apparatus of the present invention, the plasma of the processing gas for processing the object to be processed can be easily generated by generating the plasma of the inert gas in advance in the airtight processing container. Since it can be started and stabilized, the plasma processing of the object to be processed can be stabilized.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of a plasma processing apparatus for carrying out the plasma processing method of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view of an embodiment of this plasma processing apparatus.

The airtight processing container 1 is made of a conductor such as aluminum, and has a shielding effect.
It is electrically grounded, for example. An oxide film, which is an insulating film, is formed on the inner wall surface of this aluminum. At the center of the processing container 1, there is provided an object to be processed 2 which is loaded and placed by a transfer device (not shown). The object 2 to be processed is, for example, a semiconductor wafer having a diameter of 8 inches or 12 inches, or a glass substrate of, for example, 600 mm × 650 mm square for forming a thin film transistor forming a liquid crystal display device.

The object 2 to be processed is temporarily fixed at a predetermined position, for example, placed on the electrostatic chuck 3 and adsorbed and held by electrostatic force. The configuration of this electrostatic chuck 3 is
A mounting 4 formed by sandwiching a copper foil with an insulating film of polyimide and having the electrostatic chuck 3 attached thereto.
A wire 5 passing through the wire 5 and an insulator 6 having a coaxial structure surrounding the wire 5 are connected via a switch 7 to one end of a DC power supply 8 for generating a DC voltage for generating an electrostatic chuck voltage.

The other end of the linear power source 8 is connected to the ground, and a direct current voltage, for example, 2 KV is applied to the electrostatic chuck 3, so that the object 2 to be processed is attracted and held during plasma processing. The mounting table 4 is made of a conductor such as aluminum and is configured to function as a lower electrode. Further, the surface of the mounting table 4 acts as an adsorption surface, and the material thereof is an oxide film which is an insulating film. A wiring 9 is connected to the inside of the mounting table 4, and a high frequency power source 11 is further connected via the matching circuit 10 by the wiring 9.

The high-frequency power supplied from the high-frequency power source 11, for example, several hundreds of KHz, causes the mounting table 4 to draw ions or active species in the plasma in the vertical direction with respect to the object to be processed 2 to thereby increase the plasma processing speed. Is configured to enhance the

A temperature adjusting mechanism for controlling the temperature of the mounting table 4 by circulating a temperature-controlled medium inside the mounting table 4 in order to keep the object 2 to be processed during plasma processing at a predetermined temperature. 12 are provided. As a medium used in the temperature adjusting mechanism 12, a coolant liquid is used at 0 ° C. to room temperature, and temperature-adjusted liquid nitrogen is used in a temperature range of −180 ° C. to + 10 ° C. The temperature is adjusted by circulating in the formed jacket and tank. Further, in addition to the circulation of the temperature-controlled medium as a temperature control mechanism of the mounting table 4, a ceramic heater is laminated and a voltage is applied to overheat to further improve the temperature control accuracy of the cooling means. That
The temperature adjustment mechanism 1 is provided by field-backing the temperature measurement by the thermocouple embedded near the mounting surface of the mounting table 4.
It is configured so that accurate temperature control can be achieved by performing two controls.

The mounting table 4 is configured to function as a lower electrode on which the object to be processed is mounted by being electrically insulated by providing a ceramic plate, for example, on an insulating table between the processing table 1 and the processing container 1. Has been done. Further, the mounting table 4 is provided with three pusher pins that can move vertically in the vertical direction, penetrate the electrostatic chuck 3, and the pusher pins are lifted to move the object 2 to be processed into these three. The object to be processed is configured to be placed at a predetermined position on the electrostatic chuck 3 when the pusher pin receives and descends.

An opening 4 provided in the electrostatic chuck 3 is provided between the electrostatic chuck 3 and the back surface of the object to be processed 2.
1, a back cooling gas, for example, He gas is supplied to the back cooling gas supply pipe 42 to transfer the temperature of the mounting table 4 to the object 2 to be plasma-processed in a vacuum atmosphere. Since the heat transfer of the back cooling gas is mainly determined by the gas pressure of the He gas, the back cooling gas that adjusts the pressure of a slight space between the back surface of the object to be processed and the mounting surface is an electrostatic chuck. It is configured to be supplied to the rear surface side of the object to be processed 2 via 3.

A focus ring 40 surrounds the object to be processed 2 on the electrostatic chuck 3 on which the object to be processed 2 is placed, and the object to be processed is placed in the height direction. It is provided in a donut shape having a height higher than the surface of the body to be processed of the body 2. The focus ring is made of a dielectric material, for example, quartz, and is configured to concentrate plasma on the surface to be processed and increase the efficiency of plasma processing.

Next, the inside of the processing container 1 is provided with an exhaust gas provided on the bottom surface of the processing container 1 so that it can be set to a predetermined vacuum pressure, for example, a predetermined pressure of several Torr to 1 × 10 ⁻⁸ Torr. An exhaust pipe 15 connected to the port 14 is connected to an exhaust means 17 via an openable / closable valve 16, and as the exhaust means 17, exhaust is performed by a dry pump, and a turbo molecular pump is operated at a predetermined pressure. It is designed to switch and exhaust. Further, a gate valve 18 that can be opened and closed is provided on the side wall of the processing container 1, and the object 2 is configured to be carried in and out of the processing container 1 via the gate valve 18. ing.

Further, the processing container 1 is placed on the mounting table 4 in the processing container 1 and is disposed so as to face the object 2 to be processed which is fixed by the electrostatic chuck 3 and has a flat surface of substantially the same size. The shower head 19 is provided by the opening formed by the spouting element. The shower head 19 is made of a dielectric material such as quartz, and is devised in terms of material so as not to impede the electromagnetic field formed by the induction means.

The opening of the shower head 19 has a larger area as a whole than the surface to be processed of the object 2 to be processed, and holes having a diameter of 0.5 to 2 mm are adjacent to each other at equal intervals in the area. , Are arranged at intervals of 2 to 10 mm, for example.
With this structure, the gas supplied from the shower head 19 is uniformly supplied to the surface to be processed by the object 2 to be processed. This shower head 19
Is connected to a valve 21 which can be opened and closed by a pipe 20 through a side wall of the processing container 1. Further this valve 2
1, the inert gas supply means 23 via the mass flow controller 22 and the processing gas supply means 25 via the mass flow controller 24 are connected to a common pipe 26 so that they are connected to each other by common pipes. It is configured. The inert gas supply means 23 is configured to supply an inert gas such as Ar (argon), Xe (xenon) N ₂ (nitrogen), and He (helium).

From the processing gas supply means 25, a single or a plurality of processing gases corresponding to the plasma processing content of the object 2 to be processed, for example, 256KDRAM to 1MDRAM, the gate electrode and the bit line wiring are WS by CVD.
The Ix film has been widely used, and the WSIx film, which is a refractory metal silicide having a low resistance, has also been used after 4M DRAM. A low temperature WSIx film using SiH ₄ gas as a processing gas for forming this refractory metal film, or Si
It is possible to select or combine them according to their respective purposes such as formation of a high temperature WSIx film using H ₂ Cl ₂ gas. Further, the inert gas supply means 23 and the processing gas supply means 25 can mix the respective gases through the common pipe 26 and supply the mixed gases through the shower head 19. It is also possible to provide independent pipes up to the head 19 and mix the gas for the first time in a plurality of diffusion plates in the shower head 19.

Further, the window of the dielectric 27 is provided on the upper wall surface of the processing container 1 which is placed on the mounting table 4 and which faces the object 2 fixed by the electrostatic chuck 3. ing. The dielectric 27 is made of, for example, quartz as a material, has a size of 10 to 100% larger than the surface to be processed of the object 2 to be processed, and covers the surface to be processed in a region opposite to the arranged surface to be processed. It is provided to do.

The dielectric 27 is preferably made of a material that does not interfere with the electromagnetic field by the induction means provided outside the processing container 1. A material that allows control of the electromagnetic field may be used if necessary. The control of the electromagnetic field is, for example, uniform in the central portion and the peripheral portion. Further, the shape needs to be sufficient to stably maintain the generated plasma. Since the processing container 1 has a pressure resistance corresponding to the vacuum pressure, a thickness of 30
Although a quartz plate of ˜50 mm is used, if it is not possible to withstand the pressure difference from the atmospheric pressure, it is advisable to use a technique of providing vacuum chambers on both sides of this dielectric 27 to reduce the pressure difference.

Further, a guiding means 28 is provided above the dielectric 27, that is, facing the object 2 to be processed. This means 28 is a coil, for example, and preferably a plane coil. Although the number of turns depends on the frequency, it may be about one turn. This guiding means 28 has an electric wire 29.
The matching circuit 30 and the high frequency power supply 31 are connected via the.

As the guiding means 28, a substantially flat spiral coil is used as a material, and a copper plate having a thickness of 1 to 5 mm or a copper pipe having an outer diameter of 3 to 5 mm and an inner diameter of 1 to 4 mm is spirally wound, for example, for one turn. It is formed by a coil obtained by molding only. As the high frequency power source 31, a high frequency of 1 MHz to 200 MHz can be supplied, and further, a low frequency of 100 KHz can be mixed and supplied according to the content of plasma processing.

The plasma processing apparatus is constructed as described above. Next, the operation of this plasma processing apparatus will be described. Prior to being loaded into the processing container 1, the object to be processed 2 is placed under a predetermined vacuum atmosphere, for example, under a pressure of 1 × 10 ^-2 Torr in a vacuum reserve chamber (not shown) usually called a load lock. The vacuum preliminary chamber and the processing container 1 can communicate with each other via a gate valve 18.

Before the communication with the vacuum preliminary chamber, the inside of the processing container 1 is closed with the gate valve 18 closed.
The exhaust means 17 provides a predetermined pressure, for example, about n × 10 ^-2 T
Evacuate to orr (1 ≦ n ≦ 9, n is an integer). Next, a transfer device (not shown) provided in the vacuum preliminary chamber,
For example, the object to be processed 2 is carried into the processing container 1 by a transfer robot, three lift pins (not shown) are lifted on the electrostatic chuck 3, and the lift pins are received by the transfer robot. By lowering these three lift pins, the object 2 to be processed is placed on the electrostatic chuck 3. Next, the DC voltage of the DC power source 8, for example, 2 KV, is applied to the electrostatic chuck 3 by turning on the switch 7.

From the shower head 19 arranged to face the object 2 to be treated, an inert gas, for example, Ar (argon) gas supplied by the inert gas supply means is introduced. The pressure inside the processing container 1 is set by controlling the exhaust means 17 and the valve 15 so that a predetermined vacuum pressure, for example, 1 × 10 ⁻² Torr is obtained.

Next, a high frequency voltage supplied from a high frequency power source 31, for example 13.56 MHz, is applied to the induction means 28, and plasma is generated in the processing container 1. The generation of the plasma of this inert gas is performed for a predetermined time, for example, 1 to
When it is continued for 120 seconds, the plasma is stopped by stopping the introduction of the inert gas and the application of the high frequency voltage to the induction means 28. It is not preferable that the plasma generation time is a long time, for example, several seconds, for example, 1
~ 3 seconds is most desirable. This is because long-time plasma generation causes unnecessary processing on the object to be processed. Further, the present inventor has confirmed that even if the processing apparatus is left for 30 minutes after the plasma generation by the inert gas for several seconds, the plasma generation of the processing gas thereafter becomes easy.

The inventor of the present invention has performed the plasma conversion of the inert gas for several seconds in order to process the surface to be processed of the object 2 to be processed, the inner wall surface of the processing container 1, the exposed surface of the mounting table 4 and the focus ring 40. It is considered that the electrical conditions such as the surface of the are adjusted for the plasma generation.

Next, a processing gas such as CHF ₃ as an etching gas is introduced from the processing gas supply means 25 into the processing container 1 through the shower head 19, and the inside of the processing container 1 has a predetermined process pressure, for example, 1 × 10 ^-3 Torr
The exhaust means 17 and the valve 16 are evacuated so as to set As processing gas, CVD gas, sputtering gas,
Select according to the type of processing such as ion implantation gas.

Next, a high frequency voltage is applied to the induction means 28 to generate a plasma of the processing gas in the processing container 1. Further, a frequency selected from the frequency band of 1 KHZ to 200 KHZ, for example 100 KHz, is applied as a high frequency from the high frequency power source 11 to the mounting table 4. Next, a back cooling gas, such as He gas, for the purpose of heat transfer to the back surface side of the object 2 is supplied from the opening 4 opened in the electrostatic chuck 3, and the temperature of the temperature adjusting mechanism 12 of the mounting table 4 is increased. Is transmitted to the object to be processed 2 and the object to be processed 2 is set to a predetermined process temperature. The target object 2 is processed for a predetermined time by the plasma of the processing gas.

Next, when the plasma processing of the object 2 is completed, the supply of the processing gas, the application of the high frequency voltage to the induction means 28 and the application of the high frequency voltage to the mounting table 4 are stopped, and the plasma is stopped. . Next, the supply of back cooling gas to the back surface of the object to be processed is stopped, and then the voltage application to the electrostatic chuck 3 is stopped.

After that, the process of carrying out the object 2 is carried out. That is, the processing gas and the reaction products in the processing container 1 are once evacuated to a predetermined vacuum pressure, and then an inert gas such as N ₂ (nitrogen gas) is supplied from the shower head 19 to a predetermined vacuum. Pressure, eg N _{2 at} 1 × 10 ^-2 Torr
The gate valve 18 is opened after the gas atmosphere is set and the pressure in the vacuum preliminary chamber is set to be equal to or slightly negative.
At this time, the object to be processed 2 raised by a lift pin (not shown) is held by a transfer device (not shown) and transferred to the vacuum preliminary chamber.

The plasma processing apparatus operates as described above. In the above description, the example in which the plasma of the inert gas is completely stopped and then the plasma of the process gas is generated by introducing the process gas has been described. The advantage of this method is that the vacuum pressure at the time of introducing the processing gas can be separated without depending on the vacuum pressure at the time of introducing the inert gas, and can be set to the process pressure for plasmatizing the processing gas. Therefore, it is easy to stabilize the start-up of the plasma of the processing gas, and the processing result does not vary from one processing object to another as long as the process pressure does not fluctuate.

On the other hand, paying attention to the stabilization of the plasma startup of the processing gas, before the plasma is stopped by the inert gas and after the plasma is generated as the processing gas is introduced, that is, the plasma of the inert gas and the processing gas. It is also possible to finally convert 100% of the processing gas into plasma by sequentially switching the comparison of the introduced gases from the plasma of the inert gas to the plasma of the processing gas. Also in this case, as in the first example, by introducing an inert gas prior to the introduction of the processing gas and converting it into plasma, a lower vacuum pressure n × 10 ⁻³ Torr (1 ≦ n ≦
(9, n are integers) to n × 10 ⁻⁸ Torr, the plasma generation of the process gas can be easily started up as compared with the case where the inert gas is introduced and the plasma is generated.

Further, the inert gas plasma is n × 10 ^-2.
It has been confirmed by experiments that the plasma of the processing gas is sufficiently effective even in the vicinity of Torr and for a few seconds. Furthermore, the inert gas is plasmatized for a few seconds under a vacuum pressure in the vicinity of n × 10 ^-2 Torr. After that, the introduction of the inert gas is stopped and the evacuation is performed to a predetermined vacuum pressure, for example, n ×
After maintaining about 10 ^-3 Torr for about 30 minutes, N
The present inventor has confirmed that plasma can be generated sufficiently easily even in an experiment in which a processing gas is introduced at a pressure of × 10 ^-3 Torr to start up plasma.

An embodiment of the plasma processing method of the present invention is shown in FIG. A flow chart in the case of using the plasma processing apparatus will be described with reference to FIG. FIG.
[Fig. 4] is a graph showing changes in pressure inside the processing container 1 when the process shown in this flowchart is carried out.

In FIG. 2, step 1: The object 2 to be processed is loaded and placed in the processing container 1. Step 2: The gate valve 18 is opened, and the inside of the airtight processing container 1 is pressurized to a predetermined pressure, for example, 1 × 10 ⁻⁴ To.
The exhaust means 17 evacuates to rr. Step 3: An inert gas such as Ar (argon) is introduced from the inert gas supply means 23, and the processing container 1 is evacuated to a predetermined pressure, for example, 1 × 10 ^-2 Torr.

Step 4: A high frequency voltage is applied from the high frequency power source 31 to the induction means 28 to generate plasma for several seconds. Step 5: Stop the introduction of the inert gas and at the same time stop the application of the high frequency voltage. Step 6: The processing gas is introduced from the processing gas supply means 25 into the processing container 1 via the shower head 19.

Step 7: While introducing the processing gas, the pressure inside the processing container 1 is set to a predetermined pressure of 1 × 10 ⁻³ Torr. Step 8: Apply a high frequency voltage to the induction means 28,
Plasma is generated in the processing container 1. Step 9: Treat the object 2 with plasma. Step 10: Stop the introduction of the processing gas and at the same time stop the application of the high frequency voltage.

By executing the above steps,
An inert gas plasma is generated for a few seconds with respect to steps 4-5. Further, the plasma processing time of the processing gas, for example, 60 seconds to 120 seconds is generated.

The advantages of the plasma processing method described above are, firstly, that the plasma of the processing gas can be easily started up and the plasma generation can be stabilized. Secondly, since the introduction of the inert gas is stopped after the plasma is generated by the inert gas, the inert gas is not mixed with the process gas and the process gas is not diluted, so that the process gas is uniform. The point is that plasma processing can be performed.

Next, a second embodiment of the present invention will be described. The plasma processing apparatus using the induction means is characterized in that the vacuum pressure range in which plasma can be generated is wide ranging from several Torr to 1 × 10 ⁻⁶ Torr. However, at a pressure lower than 1 × 10 ⁻³ Torr, it is difficult to introduce the processing gas to start the plasma, and therefore, the inert gas is relatively high pressure, for example, several Torr to 1 × 10 ^−2. The technique for converting the processing gas into plasma after forming the plasma at a predetermined pressure within the range of Torr is as described above.

However, except that the processing gas is diluted with the inert gas, the processing gas is introduced while the plasma is generated by the inert gas, and the atmosphere in the processing container 1 is sequentially changed to the plasma of the processing gas. At the same time, the pressure in the processing container 1 is changed to a predetermined processing pressure, for example, 1 × 10 ⁻⁴ To.
By setting rr, the plasma of the processing gas can be raised relatively easily and the plasma processing of the object 2 can be performed.

A flow chart of this embodiment is shown in FIG. This flow chart will also be described using the plasma device shown in FIG.

The difference between the flow chart of the first embodiment shown in FIG. 2 and the second embodiment shown in FIG. 4 is that in step 4 of FIG. 4, a high frequency voltage is applied to the induction means 28. The point is that after the inert gas is introduced in step 3, plasma is generated in step 4, and then the process gas is introduced in step 6 while maintaining the plasma. During this time, in step 5, while maintaining the plasma of the inert gas, the pressure in the processing container is exhausted to a predetermined pressure at which plasma processing with the processing gas is performed. The pressure is 1 × 10 ^-3 Torr. By passing through such steps, the plasma can be stably generated without changing the pressure at the start of the plasma processing with the processing gas, so that the processing content can be stabilized.

Then, in the next step, the introduction of the inert gas is stopped in tandem with the introduction of the processing gas, and the plasma is generated from 100% of the processing gas. According to the above plasma processing method, the processing apparatus using plasma generation using the induction means has a vacuum pressure range which is difficult to achieve with the conventional processing apparatus using plasma generation using parallel plate type counter electrodes. , For example, 1 × 10 ⁻³ Torr to 1 × 1
The plasma treatment can be performed even at 0 ^-6 Torr. Furthermore, the advantage of the second embodiment is that the plasma generated in the processing container is switched to the plasma by the processing gas without stopping in the middle, so that the plasma processing according to the dilution of the processing gas by the inert gas can be performed. There is the choice of change.

The plasma processing method has been described above.
As the inert gas used in these plasma treatments, Ar (argon), Xe (xenon), Kr (krypton), He (helium) and N ₂ (nitrogen) gases are selected according to the choice of the treatment gas. Can be done. Further, the plasma treatment includes an etching treatment, a film forming treatment, and an ashing treatment, and the treatment gas can be selected according to the intended treatment content. Typical examples of specific plasma processing and processing gas will be described below. For example, a thin film transistor (thin film transistor) on a glass substrate.
Stor) is formed, and by driving this transistor,
Turns on / off the liquid crystal enclosed between the pixel electrode and the counter electrode.
A list of plasma film forming processes in the manufacturing process of the thin film transistor of the liquid crystal display device for FF display and the type of film forming and process gas is shown.

It shows in [Table 1].

[Table 1] Also, a list of etching targets and processing gases in the manufacturing process of the thin film transistor of the liquid crystal display device is shown.

It shows in [Table 2].

[Table 2] The above examples of plasma processing and processing gas have been described.
As an inert gas, for the above plasma treatment,
A plasma can be generated in advance using Ar (argon) gas. In selecting the type of the inert gas, a gas that does not adversely affect the process can be selected according to the type of the process gas and the content of the process performed by the plasma.

Next, a preferred embodiment in which the processing apparatus and the processing method of the present invention are applied to a cluster tool type processing system will be described with reference to the drawings. FIG. 5 is a schematic sectional view of a cluster tool type processing system. In the airtight common transfer chamber 100, a transfer device 10 for transferring the object to be processed
1 is provided. A plurality of gate valves, for example, three gate valves 1 are provided on the sidewall of the common transfer chamber 100.
02, 103, and 104 are provided so that they can be opened and closed. Further, airtight processing vessels 105, 106 and 107 are connected to the gate valves 102, 103 and 104, respectively, and are arranged radially around the common transfer chamber 100, and are opened by the openings of the gate valves 102, 103 and 104. The common transfer chamber 100 and the processing vessels 105, 106 and 107 are provided so as to selectively communicate with each other.

These processing vessels 105, 106, 10
At least one of the seven can be configured by applying a processing apparatus for processing an object to be processed by generating plasma by the guiding means of the present invention. Therefore, in the central portion of each of the processing vessels 105, 106 and 107 of FIG. 5, the guiding means 108, 109 and 110, for example, a planar spiral coil is schematically shown. Also, the processing vessels 105, 1
A parallel plate type plasma processing apparatus conventionally used as 06 and 107, a thermal CVD apparatus, an ECR type plasma processing apparatus, a sputtering apparatus, an ashing apparatus, an etching apparatus, etc. can be incorporated corresponding to the intended processing contents. It goes without saying that you can do it.

Further, the processing vessels 105, 106, 1
The communication between 07 and the common transfer chamber 100 is controlled so that any one of the gate valves is opened at the same time, so that the processing contents do not affect other objects to be processed. Further, the processing vessels 105, 106, 10
The processing content of 7 may be parallel processing of the same processing, that is, the same processing may be performed on a plurality of objects to be processed, or the same objects may be sequentially processed, for example, in the order of processing containers 105, 10.
It is also possible to carry out a series of processing by loading and unloading into 6 and 107 and connecting them in series. As a concrete example of this series processing, three layers are formed on a glass substrate manufactured by Corning as an object to be processed, and an a-Si film (amorphous.
Silicon film), SiNx (silicon nitride film), n + type a
An example is a plasma CVD apparatus that forms a Si film to manufacture a thin film transistor. By using the induction means in the plasma source of this plasma CVD apparatus, it is possible to perform uniform plasma processing on the object to be processed having a large area. For the cleaning means of the dielectric used at this time, the cleaning method using the inert gas or plasma thereof of the first embodiment and the second embodiment described above can be applied. In addition, the processing container 10 has a pressure higher than the pressure in the common transfer chamber 100.
By setting the vacuum pressure in 5, 106, and 107 to be low, the processing gas in these processing containers is configured not to adversely affect other processing containers and the transfer device.

A preliminary vacuum chamber 112 is provided via a gate valve 111 provided on the side wall of the common transfer chamber 100, and the common transfer chamber 1 is opened by the opening of the gate valve 111.
It is provided so that it can communicate with 00. This preliminary vacuum chamber 11
Reference numeral 2 denotes a preheat treatment for the purpose of shortening the treatment time by heating the object to be treated to a predetermined temperature prior to the treatment in the treatment chambers 105, 106 and 107, or an object to be heated accompanying the treatment in the treatment chamber. A treatment is carried out in which the treatment object is housed in a cassette or cooled to a predetermined temperature at which a contact portion is not damaged by heat that is heated in order to place the treatment object at a predetermined place.

The inside of the preliminary vacuum chamber 112 has a predetermined vacuum pressure higher than that in the processing chambers 105, 106, 107 and the common transfer chamber 100, for example, n × 10 ⁻³ Tor.
As the preheating means which is maintained at a pressure of r to n × 10 ^-2 Torr, there are a preheating means that uses heat generated by an electric resistor provided on a mounting table of the object to be processed, a direct heating of the object to be processed by a lamp, There is something to use. As the cooling means, it is possible to cool to a predetermined temperature by circulating a coolant such as a coolant or liquid nitrogen on the mounting table of the object to be processed. Furthermore, it is also possible to incorporate these preheating and cooling into a multi-layer stage to treat a plurality of objects to be treated at predetermined temperatures.

The transfer platform 101 provided in the common transfer chamber 100 transfers an object to be processed between the preliminary vacuum chamber 112 and the plurality of processing vessels 105, 106 and 107. Further, a gate valve 113 is arranged on the side wall of the preliminary vacuum chamber 112 so as to face the gate valve 111. The preliminary vacuum chamber 112 is provided so as to be able to communicate with the airtight second transfer chamber 114 via the gate valve 113. In the second transfer chamber 114,
A second transfer device 115 is provided.

Further, a gate valve 115 is provided on the side wall of the second transfer chamber 114 at a position facing the gate valve 113. This gate valve 115
The second transfer chamber 114 is connected to the cassette chamber 11 via
6 is provided so as to be able to communicate. This cassette room 116
Inside, there is provided a mounting means (not shown) for mounting at least one cassette 117 capable of accommodating a plurality of, for example, 25 objects to be processed in a horizontal position. The cassette chamber 11
A gate valve 118 is provided on the side wall of the gate valve 6 facing the gate valve 118 so that the gate valve 118 can communicate with the outside of the processing system through an opening.

The operation of the processing system configured as above will be described. An object to be processed stored in a cassette by another processing system, for example, an automatic transfer system such as a robot (AGV) from the semiconductor manufacturing process, is provided at a predetermined position in the cassette chamber 116 via the gate valve 118 together with the cassette. It is positioned and placed on the mounting table. When the gate valve 118 is opened and the inside of the cassette chamber 116 is replaced with an inert gas, for example, N ² , the gate valve 115 is opened and the second transfer chamber 114 in the adjacent chamber is opened.
By the transfer device 115, the object to be processed in the cassette 117 is carried out sheet by sheet, and is transferred to the preliminary heating means in the preliminary vacuum chamber 112.

Next, when the gate valve 113 is closed and the inside of the preliminary vacuum chamber 112 is exhausted to a predetermined pressure and the preheating of the object to be processed is completed, the gate valve 111 is opened and the transfer device 101 is moved to the preliminary vacuum chamber 112. The object to be processed is received inside, is transferred to the inside of the common transfer chamber 100, and the gate valve 111 is closed.

Next, the object to be processed is carried into the selected processing container 105, 106, 107 from the common transfer chamber 101 by the transfer device 101, and predetermined processing is sequentially performed.
The object to be processed after the next processing is transported to and stored in a predetermined cassette 117 in the cassette chamber 116 following the reverse course. The above is a series of processing operations.

In the processing system configured and operated as described above, the cleaning for the adhesion of the reaction product or the like to the dielectric in the processing apparatus is performed by stopping the entire processing system or disassembling the apparatus. However, it is required to be carried out in parallel with the processing as much as possible. By applying the processing method of the present invention to this processing system, cleaning is performed in parallel with the processing of the object to be processed in the other processing apparatus without stopping the entire cluster type processing system. It is possible to make a great contribution to the improvement of production efficiency.

According to the plasma processing method or the plasma processing apparatus of the present invention, the plasma of the processing gas for processing the object to be processed is generated by preceding the generation of the plasma by the inert gas in the airtight processing space. Since it can be easily started and stabilized, the treatment of the object to be treated with plasma can be stabilized.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a plasma processing apparatus for carrying out a plasma processing method of the present invention.

FIG. 2 is a flowchart showing an embodiment of the plasma processing method of the present invention.

FIG. 3 is a graph showing a pressure change in a processing container when plasma processing is performed according to the flowchart shown in FIG.

FIG. 4 is a flowchart showing another embodiment of the plasma processing method of the present invention.

FIG. 5 is a schematic diagram showing an embodiment of a cluster tool type processing system incorporating the plasma processing apparatus of the present application.

[Explanation of symbols]

 1 Processing Container 2 Processing Object 3 Electrostatic Chuck 19 Shower Head 28 Induction Means 31 High Frequency Power Supply

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Claims (13)

[Claims] 1. A plasma generation method in which an object to be processed provided in an airtight processing container is processed by inducing a plasma in the inducing means, and an inert gas is introduced into the processing container to generate the plasma in the inducing means. And a second step of introducing a processing gas for processing the object to be processed into the processing container and generating plasma by the inducing means to process the object. A plasma processing method comprising: 2. The inert gas and the processing gas are provided in the processing container, and are introduced by a dielectric shower head arranged facing the object to be processed. The plasma processing method according to item 1. 3. The pressure in the processing container in the second step is lower than the pressure in the processing container in the first step. Plasma treatment method. 4. The plasma according to claim 1, wherein in the second step, the processing gas is introduced after the pressure inside the processing container is set to a predetermined pressure. Processing method. 5. A first step of loading and placing a target object in an airtight processing container, and an inert gas having a predetermined pressure by introducing an inert gas into the processing container and performing vacuum exhaustion. A second step of forming a gas atmosphere, a third step of generating plasma in the processing container by an induction means, and then stopping the introduction of the inert gas, and introducing the processing gas into the processing container. And a fourth step of applying a high frequency to the inducing means to convert the processing gas into plasma and processing the object to be processed. 6. The inert gas is Ar (argon), X
e (xenon), Kr (krypton), He (helium) or N ₂ (nitrogen) gas, the predetermined pressure is 1 × 10 ^-3 Torr to 1 × 10 ^-1 Torr, and the induction means Is a coil, and the plasma processing method according to claim 5. 7. The pressure in the processing container when the processing gas is introduced into the processing container in the fourth step to generate plasma is 1 × 10 ⁻⁶ Torr to 1 × 10 ⁻² Torr.
The plasma processing method according to claim 5, wherein 8. A first step of carrying in and placing an object to be processed in an airtight processing container, and introducing an inert gas into the processing container to evacuate the object to ensure that a predetermined pressure is maintained. A second step of forming an active gas atmosphere, a third step of applying a high frequency to the induction means to generate plasma in the processing container, and a process gas while continuing to generate the plasma in the processing container. A fourth step of introducing the processing gas into plasma to process the object to be processed, the plasma processing method. 9. The inert gas introduced in the second step is Ar (argon), Xe (xenon), Kr.
(Krypton), He (helium) or N ₂ (nitrogen) gas, and the predetermined pressure is 1 × 10 ⁻³ To.
9. The plasma processing method according to claim 8, wherein rr to 1 × 10 ⁻¹ Torr. 10. The plasma according to claim 8, wherein the introduction of the inert gas into the processing container is stopped after the processing gas is turned into plasma in the fourth step. Processing method. 11. An airtight processing container in which an object to be processed is placed, induction means for generating plasma of an inert gas introduced into the processing container, and the processing gas is introduced into the processing container. A plasma processing apparatus comprising: a processing gas introduction unit, wherein the processing gas is turned into plasma by the guiding unit to process the object to be processed. 12. An airtight processing container in which the carried-in target object is placed, and an evacuation means for evacuating the inside of the processing container to create an inert gas atmosphere of a predetermined pressure by the inert gas introduced. And a guiding means for generating plasma of the inert gas, and a processing gas introducing means for introducing a processing gas into the processing container, and the guiding means in the processing container at a predetermined pressure by the exhaust means. The plasma processing apparatus is characterized in that the processing gas is turned into plasma by the method to process the object to be processed. 13. An airtight processing container in which the carried-in target object is placed, an induction means for generating plasma of the inert gas introduced into the processing container, and while continuing to generate the plasma. A plasma processing apparatus comprising: a processing gas introducing unit that introduces a processing gas into the processing container; and the object to be processed is processed by the processing gas that has been turned into plasma by the guiding unit.