JP2002184764A - Plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome such a problem that in a conventional plasma processing apparatus, the in-plane distributions of active species and by-product gas which contribute to plasma processing are not necessarily uniform since exhausting is conducted only in the periphery of a work piece. SOLUTION: A plasma processing apparatus comprises a gas blowing-out means having a plurality of gas blowout ports 18 in the surface opposite with the work piece 8. By blowing out at least two kinds of mixed gases of different flow rates from different gas blowout ports, the work piece can be uniformly plasma-processed. Gas intake ports formed in the surface opposite with the work piece also contribute to the uniform plasma processing of the work piece.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a plasma processing apparatus and a plasma processing method for performing processing such as fine processing on an object to be processed such as a CD substrate using plasma.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, in order to subject a target object such as a semiconductor wafer or an LCD substrate to a desired fine processing, a plasma etching apparatus for converting a reactive gas introduced into a processing chamber into a plasma by an electromagnetic wave is widely used. It's being used.

FIG. 7 shows a parallel plate type ECR using UHF.
FIG. 1 shows a cross-sectional view of a plasma etching apparatus (Japanese Unexamined Patent Publication No. 9-3).
No. 21031). Inside the etching processing chamber 1, a planar antenna 2 and a processing table 9 are installed. The UHF band electromagnetic wave generated by the high-frequency power supply 11, for example, 450 MHz, is
3 through which the gas in the processing chamber is turned into plasma.
At this time, a magnetic field is generated by the solenoid coil 17,
It is also possible to generate highly efficient discharge.

A high frequency having a frequency different from that of the high frequency power supply 11, for example, 13.56 MHz, is introduced from the high frequency power supply 12 through the high frequency filter 14 to the planar antenna 2, and a bias can be applied thereto. By applying a bias to the planar antenna 2, the plasma can be modified by a surface reaction on the surface of the shower plate 10. In order to optimize this surface reaction, the planar antenna 2 has a temperature adjusting means. Further, the material of the shower plate 10 can be selected. For example, Si can be selected.

The object 8 is fixed to the processing table 9 by an electrostatic chuck provided on the processing table 9. The processing table 9
Further, it has a temperature adjusting means for adjusting the temperature of the object to be processed, and can apply a high frequency bias to the object to be processed by a high frequency, for example, 800 kHz, introduced from the high frequency power supply 15 through the matching unit 16. I have.

Further, the processing table 9 has a focus ring 7
Is installed. A high frequency generated from the high frequency power supply 15 can be branched and a bias can be applied to the focus ring 7. The position of the processing table 9 is the plane antenna 2
From 20 mm to 150 mm. The gas is introduced into the gas introduction port 5, passes through the planar antenna 2 and the gas introduction path provided in the shower plate 10, and is ejected from the gas ejection ports 18 provided in the shower plate 10 to the etching chamber.

One type of mixed gas whose flow rate and flow rate ratio are controlled by a plurality of mass flow controllers is branched and flows through a plurality of gas jet ports 18. Gas exhaust is performed by connecting gas exhaust means to the exhaust port 19.

[0008]

In a plasma processing apparatus, in order to perform uniform plasma processing on an object to be processed, active species such as ions and radicals generated from an introduced gas and involved in the plasma processing are to be processed. It is necessary to distribute the gas at a uniform concentration over the entire processing surface and quickly exhaust the by-product gas generated by the plasma processing while maintaining the uniform concentration at the entire processing surface.

However, if only gas is exhausted from the peripheral portion of the object to be processed, as in the conventional plasma apparatus, as shown in FIG. 8, the gas ejected from the central portion of the shower plate and the gas ejected from the peripheral portion are reduced. A difference occurs in the staying time between the shower plate and the object, and the concentration distribution of the active species is not uniform over the entire processing surface of the object. Similarly, the by-product gas generated on the surface of the object to be processed or the surface of the planar antenna does not have a uniform distribution. In addition, when the distance between the planar antenna 2 and the processing table 19 is smaller than the length of the processing target and the gas flow rate is large, a difference in gas pressure may occur between the central portion and the peripheral portion of the processing target. . From the above,
It has been difficult to achieve favorable processing conditions.

On the other hand, by increasing the gas flow rate and optimizing the position and area of the gas ejection port, the time during which the gas stays in the region contributing to the plasma processing is shortened, and the plasma processing is made uniform. Ingenuity has been devised. But,
It is clear that miniaturization and diversification of materials will progress in the semiconductor manufacturing process, and it is necessary for manufacturing apparatuses to provide more uniform processing performance so as to be able to handle more materials. On the other hand, the above solution is not enough,
Further improvement is needed.

The present inventors have made the present invention based on such technical grounds, and the object of the present invention is to achieve a good shape and high-speed processing in a wider variety of materials. Another object of the present invention is to provide a plasma processing apparatus and a plasma processing method including a gas ejection method and a gas exhaust method that can obtain good in-plane uniformity of processing characteristics.

[0012]

According to the present invention, there is provided a gas ejection means having a plurality of gas ejection ports on a surface facing an object to be processed, and the gas supplied by the gas ejection means is turned into plasma to form a plasma on the object. A plasma processing apparatus for performing a process is characterized by having gas ejection means for ejecting at least two types of mixed gas having different flow rate ratios from different gas ejection ports.

Further, according to the present invention, there is provided a gas ejection means provided with a plurality of gas ejection ports on a surface facing the object to be treated, and a gas supplied by the gas ejection means is turned into a plasma to process the object. The processing apparatus is characterized by having gas ejecting means for ejecting two or more types of mixed gas having different flow rates from different gas outlets.

According to the present invention, there is provided a plasma processing apparatus comprising a gas ejection means having a plurality of gas ejection ports on a surface opposed to an object to be processed, wherein the gas supplied by the gas ejection means is turned into plasma and the object is processed. In the apparatus, the object to be processed is divided into two or more regions, such as concentric or square, with the center of the object as the center, and different flow rates or flow rates different from each other from the opposing surfaces opposing each of the regions. The gas ejection means is configured to eject the mixed gas.

As described above, according to the present invention, the above-mentioned active species concentration distribution and by-product gas concentration distribution are made uniform by introducing a plurality of mixed gases having different flow rates and flow rate ratios. Can be performed.

Further, according to the present invention, by providing one or more gas inlets on the surface facing the object to be processed, the time during which the gas stays in the region contributing to the plasma processing is made as uniform as possible. , And the uniformity of the plasma processing can be improved.

[0017]

(Embodiment 1) FIG. 1 shows a basic configuration diagram of the present invention. FIG. 1 shows a parallel plate type E using UHF.
It is sectional drawing of a CR plasma etching apparatus. A cylindrical etching processing chamber 1 which is grounded and made of a conductive material, for example, aluminum or the like, has a planar antenna 2, an insulator 3, a focus ring 7, an object to be processed 8, a processing table 9 and a shower plate 10 installed therein. Have been.

The planar antenna 2 is made of a conductive material, such as aluminum, and is separated from the grounded outer wall 4 of the processing chamber by an insulator 3 such as ceramic. UH generated by the high frequency power supply 11 is
An F-band electromagnetic wave, for example, 450 MHz, is guided through the matching unit 13 and turns the gas in the processing chamber into plasma. At this time,
It is also possible to generate a magnetic field by the solenoid coil 17 and generate a highly efficient discharge by the interaction between the electromagnetic wave and the magnetic field.

A high frequency having a frequency different from that of the high frequency power supply 11, for example, 13.56 MHz, is introduced from the high frequency power supply 12 through the high frequency filter 14 to the planar antenna 2, and a bias can be applied thereto. By the bias to the planar antenna 2, active species in the plasma can be controlled by utilizing the surface reaction on the surface of the shower plate 10. In order to optimize this surface reaction, the planar antenna 2 has a temperature adjusting means. This temperature adjustment can be realized, for example, by flowing a refrigerant at 20 ° C. from the refrigerant inlet 6. Furthermore, by selecting the material of the surface of the shower plate 10, the control of active species can be optimized. For example, Si can be selected.

The workpiece 8 is fixed to the processing table 9 by an electrostatic chuck provided on the processing table 9. The processing table 9
It is possible to apply a high-frequency bias to the processing target 8 at a high frequency, for example, 800 kHz introduced from the high-frequency power supply 15 through the matching unit 16. Further, the processing table 9 has a temperature adjusting means for adjusting the temperature of the object to be processed, and the surface reaction of the object to be processed can be controlled by flowing a refrigerant at −20 ° C., for example.

Further, the processing table 9 has a focus ring 7
Is installed. A high frequency generated from a high frequency power supply 15 can be branched and a bias can be applied to the focus ring 7. The position of the processing table 9 is the plane antenna 2
From 20 mm to 150 mm. In this embodiment, the thickness is 30 mm.

The gas is ejected to the etching chamber through a gas introduction passage provided in the planar antenna 2 and the shower plate 10. FIG. 2 shows a gas introduction path provided in the planar antenna 2 and the shower plate 10. In this embodiment, two types of mixed gases having different oxygen gas flow rates were supplied to the gas inlet 5a and the gas inlet 5b. The flow rate of the mixed gas supplied to the gas inlet 5a and the gas inlet 5b is controlled by different mass flow controllers.

The gas introduced into the gas inlet 5a is blown out of a large number of gas outlets 18 provided in the shower plate 10 from a gas outlet provided in a region having a radius of 50 mm from the center of the shower plate. You. The gas introduced from the gas inlet 5b is supplied to the shower plate 1
Of the gas ejection ports 18 provided at 0, the gas is ejected from the gas ejection ports provided at an area of a radius of 55 mm to a radius of 140 mm. These two gas flow paths were separated by an O-ring 20. Gas exhaust was performed by connecting an exhaust means to the exhaust port 19. In this embodiment, a turbo molecular pump and a dry pump were used.

By introducing a mixed gas having a different flow ratio into the gas inlets 5a and 5b, the non-uniform distribution of the etching characteristics caused by the non-uniform distribution of the active species concentration and the by-product gas concentration is improved, and the uniform etching is performed. Can be performed. In this example, mixed gases having different oxygen flow rates were used. This corresponds to the fact that the uniformity of the etching rate selectivity (p-TEOS / photoresist) is poor at the center of the object and the periphery of the object, and the selectivity decreases at the peripheral portion. It is known that if oxygen is present excessively, the selectivity is deteriorated. The decrease in the selectivity can be improved by reducing the oxygen flow rate of the introduced gas only in the peripheral portion. Similarly, by changing the flow rate of the gas corresponding to the processing characteristics whose uniformity is to be improved, the processing characteristics other than the photoresist selectivity can be made uniform.

FIG. 3 shows the p-value when the mixed gas of the same flow rate is flown (case 2) for comparison with the present embodiment (case 1).
4 shows the TEOS / photoresist selectivity.

The setting conditions are as follows: gas pressure: 2 Pa, 4 Pa
50 MHz power: 800 W, 13.56 MHz power: 8
00 W, 800 kHz power: 1800 W, and gas flow rates (sccm: standard cc / minute) are as follows. Case 1) Gas inlet 5a: Ar / C5F8 / O2 = 400
/ 15/12 sccm Gas inlet 5b: Ar / C5F8 / O2 = 400
/ 15/10 sccm Case 2) Ar / C5F8 / O2 = 40
0/15/12 sccm As can be seen from FIG. 3, it can be seen that uniformity can be improved by using the present invention.

In this embodiment, a mixed gas having a different oxygen flow rate is used as a mixed gas having a different flow ratio, but the present invention is not limited to this. The present invention also provides, in addition to the above, carbon fluoride, hydrocarbon, silicon carbide, nitrogen, hydrogen, NH
3, It can be applied to all kinds of gases such as HF, HCl, HBr, F2, Cl2, He, argon, helium, neon, xenon and the like. In the present embodiment, two kinds of mixed gases having different flow ratios are ejected.
The present invention is not limited to this configuration. The present invention is applicable to a configuration in which several types of mixed gas are ejected, such as only a difference in flow rate.

Further, in the present embodiment, the area for ejecting different mixed gases is defined by a radius of 50 mm from the center of the shower plate.
mm and a concentric circle 2 having a radius of 140 mm from 55 mm
Although divided into regions, the present invention is not limited to this configuration.
For example, the object to be processed is divided into two or more regions bounded by a concentric circle or a square centered on the center of the object to be processed, and different flow ratios or different flow rates are mixed from opposing surfaces facing the respective regions. The present invention can be applied to a configuration in which gas is ejected.

The present invention can be applied to a plasma processing method and a processing apparatus to optimize the number of regions and the range of the regions. Further, in the present embodiment, a plasma etching apparatus has been described as an example of the plasma processing apparatus, but the present invention is not limited to this configuration. INDUSTRIAL APPLICABILITY The present invention is applicable to various devices and various methods for performing processing by introducing a gas into a processing chamber.

(Embodiment 2) In this embodiment, the gas introduction path provided to the planar antenna 2 of Embodiment 1 is changed, and a gas introduction path and a gas suction path are provided. FIG. 4 shows a gas introduction path and a gas suction path provided in the planar antenna.

In this embodiment, gas is supplied from the gas inlet 5b, and gas is sucked from the gas inlet 5c. The flow rate of the mixed gas supplied to the gas inlet 5b is controlled by a mass flow controller. The gas introduced into the gas inlet 5b is ejected from the gas outlets provided in the region of the shower plate 10 from a radius of 30 mm to a radius of 140 mm among the many gas outlets 18 provided in the shower plate 10. . In addition, gas is sucked in from a gas outlet 18 provided in a region having a radius of 25 mm from the center of the shower plate 10, and is exhausted through the gas inlet 5c. The gas suction area and the gas ejection area were separated by an O-ring 20.

FIG. 5 shows an exhaust method. The processing chamber 1 was evacuated from an exhaust port 19, which is a normal exhaust port, by exhaust equipment. In this embodiment, a turbo molecular pump and a dry pump are used. Further, the gas suction port 5c was evacuated from the gas suction port 5c by making a bypass pipe just above the turbo molecular pump.

In this embodiment in which air is exhausted from the vicinity of the center of the shower plate, the concentration distribution of active species and by-product gas contributing to the etching process is made more uniform than in the conventional apparatus in which air is exhausted only from the peripheral portion of the object to be processed. It is also possible to reduce the gas pressure difference between the vicinity of the center and the periphery. As a result, the in-plane uniformity of the etching characteristics can be improved.

FIG. 6 shows the case of this embodiment (case 3) and
For comparison, the etching rate selectivity (p-TEOS) in the case where the same mixed gas is flowed from the gas inlet 5c and the gas inlet 5b and exhaust is performed only from the gas exhaust port 19 (case 4).
/ Photoresist).

The setting conditions are as follows: gas pressure: 2 Pa, 4
50 MHz power: 800 W, 13.56 MHz power: 8
00W, 800 kHz power: 1800 W, gas flow rate: Ar / C5F8 / O2 = 1200/20/2
2 sccm.

It can be seen that the present embodiment of FIG. 6 enables more uniform etching. In the present embodiment, the exhaust from the gas inlet 5c is performed by bypass piping to a normal exhaust facility, but the present invention is not limited to this configuration. The present invention also includes a gas inlet 5c.
Any configuration can be used as long as it is an exhaust means, such as connecting an independent turbo molecular pump to the pump. In the present embodiment, the area where the gas is sucked and the gas is ejected are divided into two areas with a radius of 25 mm and a radius of 30 mm to a radius of 140 mm from the center of the shower plate, but the present invention is not limited to this configuration.

The present invention can be adapted to a plasma processing method and a processing apparatus to optimize the number of regions and the range of the regions. Further, in the present embodiment, a plasma etching apparatus has been described as an example of the plasma processing apparatus, but the present invention is not limited to this configuration. INDUSTRIAL APPLICABILITY The present invention is applicable to various devices and various methods for performing processing by introducing a gas into a processing chamber.

[0038]

According to the present invention, the in-plane concentration distribution uniformity of both active species and by-product gas contributing to plasma processing is achieved by using a plurality of mixed gases having different flow rates and flow rates of gases used for plasma processing. And uniform plasma processing can be performed on the object to be processed.

Further, according to the present invention, by providing a gas suction port on the surface facing the object to be processed, the uniformity of the in-plane concentration distribution of both active species and by-product gas contributing to the plasma processing is improved. The in-plane distribution uniformity of gas pressure can also be improved, and uniform plasma processing can be performed on the object.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic configuration diagram of a first embodiment of the present invention.

FIG. 2 is a sectional view showing a planar antenna and a shower plate portion of the plasma etching apparatus shown in FIG.

FIG. 3 is a view showing a selection ratio distribution obtained in Example 1.

FIG. 4 is a cross-sectional view showing a planar antenna and a shower plate portion configured in Embodiment 2 of the present invention.

FIG. 5 is a diagram showing an exhaust method according to a second embodiment.

FIG. 6 is a view showing a selection ratio distribution obtained in Example 2.

FIG. 7 is a schematic sectional view showing a conventional etching apparatus.

FIG. 8 is a schematic diagram showing a gas flow between a shower plate and an object to be processed in a conventional etching apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Plane antenna, 3 ... Insulator, 4 ... Processing chamber outer wall, 5, 5a, 5b ... Gas inlet, 5c ... Gas inlet, 6 ... Refrigerant inlet, 7 ... Focus ring, 8 ... Object to be processed, 9: processing table, 10: shower plate, 11, 1
2, 15 high-frequency power supply, 13, 16 matching unit, 14 high-frequency filter, 17 coil, 18 gas outlet, 1
9 ... gas exhaust port, 20 ... O-ring.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Izawa 1-280 Higashi Koigabo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory of Hitachi, Ltd. (72) Nobuyuki Negishi 1-280 Higashi Koigabo, Kokubunji-shi, Tokyo Hitachi, Ltd Central Research Laboratory F-term (reference) 5F004 AA01 AA05 BA14 BB11 BB32 BC02 BC03 CA02 DA00 DA04 DA20 DA22 DA23 DA26 DB23 DB26

Claims (5)

[Claims] 1. A plasma processing apparatus comprising: gas ejecting means provided with a plurality of gas ejection ports on a surface facing an object to be processed, wherein the gas supplied by the gas ejecting means is turned into plasma to process the object. In the apparatus, the gas ejection means is configured to eject two or more types of mixed gas having different flow rate ratios from the different gas ejection ports. 2. A plasma processing apparatus comprising: gas ejecting means provided with a plurality of gas ejection ports on a surface facing an object to be processed, wherein the gas supplied by the gas ejecting means is turned into plasma to process the object. In the apparatus, the gas ejecting means is configured to eject two or more types of mixed gas having different flow rates from the different gas ejection ports. 3. A plasma processing apparatus comprising: gas ejecting means provided with a plurality of gas ejection ports on a surface facing an object to be processed, wherein the gas supplied by the gas ejecting means is turned into plasma to process the object. In the apparatus, one or more gas inlets are provided on a surface facing the object to be processed. 4. The plasma processing apparatus according to claim 1, wherein one or more gas inlets are provided on a surface facing the object to be processed. 5. A plasma process, comprising: gas ejecting means provided with a plurality of gas ejection ports on a surface facing an object to be processed, wherein the gas supplied by the gas ejecting means is turned into plasma to process the object. In the apparatus, the object to be processed is divided into two or more regions bounded by a concentric circle centered on the center of the object to be processed, and mixed gases having different flow ratios are ejected from opposing surfaces opposing each of the regions. As
A plasma processing apparatus comprising the gas ejection means.