JP3408994B2 - Plasma processing apparatus and control method for plasma processing apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus or a CVD apparatus using plasma and a CV using heat.
The D device is suitable for processing a sample such as a semiconductor element substrate using a gas dissociated by plasma or a gas dissociated by heat to make the processing speed distribution in the substrate uniform. Plasma processing device or heat C
The present invention relates to a VD device and a control method for treating a substrate surface using this device.

[0002]

2. Description of the Related Art In a conventional plasma generator, for example, as described in Japanese Patent Application Laid-Open No. 9-115893,
A gas flow supply device is provided in each of a large number of holes in the shower head, and a programmable gas flow divider for distributing gas is provided in the shower head to control the flow rate distribution.

Further, as described in JP-A-5-335274, the shower diameter is 1/4 of the maximum diameter of the discharge chamber.
The following settings were made so that the reaction product was efficiently exhausted. Further, for example, as described in Japanese Patent Application Laid-Open No. 6-163467, the reaction gas ejection effective diameter is made smaller than the diameter of the wafer to prevent the reaction product from adhering to the side wall of the etching hole.

Further, for example, as described in Japanese Patent Application Laid-Open No. 7-7001, a region in which gas is ejected from pores is 120 mm within a range of 180 mm from the center of the shower electrode.
The gas supply means is controlled so that the gas passing through the pores has a mass flow rate of 620 kg / m 2 / hour or more by setting the gas flow rate so as to prevent polymer adhesion in the ejection holes. Was there.

Further, for example, as described in Japanese Patent Application Laid-Open No. 7-307334, the ratio of the processing gas ejection effective area of the upper electrode to the processing area of a sample to be processed (hereinafter referred to as a substrate) is 80 to 100% (in diameter). Converted to 89-100
%) To uniformly control the distribution of the source gas and the reaction product so that the etching rate and the in-plane uniformity of the etching shape are uniform.

A narrow electrode parallel plate type (hereinafter referred to as "narrow electrode type") etching apparatus has been put into practical use for processing a silicon oxide film. Narrow electrode type etching equipment is 1
Dozens of MHz between parallel plates with an interval of 5 mm to 30 mm
A high frequency of several tens of MHz is applied to form plasma. The source gas pressure is in the range of several tens mTorr and higher. If the radicals are consumed only in the substrate, then if the plasma diameter is larger than the substrate diameter, as described in Journal of Electrochemical Society, Vol. 136, No. 6, pp. The amount of radicals increases on the outer peripheral side, and as a result, the etching rate increases in the direction of increasing the radius of the substrate. When the plasma diameter is smaller than the substrate diameter, the amount of radicals on the outer circumference of the substrate decreases, and as a result, the etching rate decreases in the direction of increasing the radius of the substrate. Therefore, in this etching apparatus, the outer periphery of the upper electrode is covered with a ring made of an insulator such as quartz so that the plasma distribution is confined in the vicinity of the substrate and the etching rate is made uniform in the substrate. A large number of gas ejection holes are provided in this upper electrode and a so-called shower head is installed. In this case, a shower diameter of about the same as the substrate diameter (89 to 100%) is used as in the above-mentioned conventional technique. This narrow electrode type etching device is characterized in that the oxide film etching characteristics can be obtained relatively stably over a long period of time.

[0007]

In etching in the manufacture of semiconductor devices, the uniformity of the etching rate distribution of the film to be etched, the underlayer film or the resist in the substrate, the anisotropy of the etching shape, and the high selection ratio for the underlayer film or the resist. Is required. In plasma, gas dissociates, and ions and several types of radicals (active species: chemically active neutral molecules)
Is generated. Etching occurs due to surface reactions of these ions and radicals and reaction products that re-enter.
Each film (resist film, film to be etched, base film)
Are processed by different reactions due to ions, radicals, re-incident reaction products, etc. Therefore, in order for the distribution of the etching rate of each film to be uniform within the substrate, it is required that the incident amounts of ions and various radicals and re-incident reaction products on the substrate have a uniform distribution within the substrate. To be done.
Ions in the plasma are accelerated by the sheath electric field generated near the surface of the substrate and vertically enter the substrate. Therefore,
If the plasma density and sheath voltage are uniform on the substrate,
The incidence of ions becomes uniform on the substrate.

On the other hand, radicals are generated by dissociation from the source gas in the region where plasma is distributed in the chamber, but since they are neutral, they are spatially isotropic without being affected by the magnetic field or sheath electric field. Diffused and carried by the gas stream,
The radicals that have disappeared or adhered to the substrate or the walls of the chamber with different reaction probabilities are exhausted from the exhaust port by the gas flow together with other gas components.

Therefore, the radicals have different density distributions in the chamber depending on the type. For example, when a fluorocarbon gas such as CF4 is dissociated in plasma, radicals such as F, CF, CF2, CF3, and CF polymer are generated. Fluorine F radicals are consumed by the etching reaction on the substrate and the upper electrode made of silicon, but they are not consumed on other wall surfaces.

Therefore, if the plasma spreads over the entire chamber, the F radicals become excessive on the outer peripheral side of the substrate, the etching rate increases in the direction of increasing radius on the substrate, and the etching rate becomes nonuniform. It was CF2 adheres to the wall as a whole and causes an etching reaction on the surface of SiO2 exposed on the substrate, assisted by ion collision. If the flux of CF2 on the substrate is sufficient, the amount of ions incident on the substrate during etching is rate-determining, so that the distribution of the amount of ions incident on the substrate can be made uniform by improving the apparatus. The Si film and the Si3N4 film have a high probability of reacting with F radicals and a low probability of reacting with CF2. Si3N
In the etching of the SiO 2 film using the 4 films as the base film, the F radicals are consumed by the upper electrode made of silicon to increase the incident flux ratio of CF 2 / F or CF 3 / F on the substrate, and to the base film (Si 3 N 4) The etching selection ratio of the film to be etched (SiO2) is controlled to be high.

However, although the amount of F radicals is small, the density increases in the radial direction on the substrate in the same manner as described above, so that the etching rate of the underlying film becomes nonuniform on the substrate, and the selection ratio becomes nonuniform. Has become. Further, in an apparatus having an exhaust port on the outer peripheral side of the substrate, after etching,
The density distribution of the ejected reaction products on the substrate has a non-uniform distribution such that it is high at the center of the wafer and low at the outer periphery. As described above, even if the ions are uniformly incident on the substrate, various radicals and reaction products have different nonuniform distributions on the substrate, and thus it is necessary to control their distribution.

As described above, the distribution of various radicals and reaction products in the chamber is greatly affected by the reaction in the plasma region, gas flow and wall. However, in the conventional technique (Japanese Patent Laid-Open No. 9-115893), there is a problem that the structure becomes complicated and the product price is high because it is necessary to attach a gas flow supply device to each hole of the shower head. Further, with respect to the distribution of various radicals, no consideration has been given to setting the spread of plasma or the flow rate distribution of the shower head.

Further, in the prior art disclosed in Japanese Patent Application Laid-Open No. 5-335274, only exhausting the reaction product efficiently was considered. In addition, JP-A-6-163467
In the prior art described in Japanese Patent Laid-Open Publication No. 2003-242242, only the prevention of the reaction product from adhering to the side wall of the etching hole was considered. Further, in the conventional technique described in Japanese Patent Laid-Open No. 7-7001, only consideration has been given to increasing the gas flow velocity to prevent the polymer from adhering to the inside of the ejection hole. Also,
In the conventional technique described in Japanese Patent Laid-Open No. 7-307334,
Only the uniform control of the distribution of the source gas and the reaction product to make the etching rate and the in-plane uniformity of the etching shape have been considered.

In the above prior art, no consideration has been given to the spread of plasma and the uniformity of the flux incident on the substrate surface of radicals generated by dissociation. Further, as described in Japanese Patent Laid-Open No. 6-163467, the reaction gas ejection effective diameter is made smaller than the diameter of the wafer to prevent the reaction products from adhering to the side wall of the etching hole. In order to prevent the substances from adhering to the side wall of the etching hole, it was necessary to make the reactive gas ejection effective diameter much smaller than the substrate diameter or to flow a large amount of gas. In this case, on the contrary, the distribution of radicals becomes non-uniform, which causes a problem of non-uniform etching rate within the surface of the substrate.

Further, as described in JP-A-7-307334, the ratio of the processing gas ejection effective area of the upper electrode to the processing area of the object is 80 to 100% (89 to 100% when converted to diameter). When the plasma diameter is larger than the substrate diameter, the radicals become excessive near the outer periphery of the substrate, and the etching rate becomes nonuniform.

Further, in the etching apparatus utilizing electron cyclotron resonance as described in JP-A-3-122294 and JP-A-6-224155, since the electromagnetic wave is introduced from the position facing the substrate, the position facing the substrate is used. A dielectric that allows electromagnetic waves to pass through must be installed in this room. This dielectric is an electrical insulator,
The ground electrode necessary for applying a high frequency bias to the sample to be processed cannot be installed at a position facing the sample to be processed,
There was a problem that non-uniformity of the bias occurs and a problem that the wall cannot control to reduce unnecessary radicals.

On the other hand, in the narrow electrode type etching apparatus, it is possible to set the ground and control the radicals for the high frequency bias applied to the sample to be processed by devising the electrode material in the facing portion of the sample to be processed. is there. However, in the narrow electrode type etching apparatus, since the gas pressure used is relatively high, the directivity of the ions incident on the sample to be processed becomes non-uniform, and it is difficult to cope with future miniaturization. Further, since the electrode interval is about 30 mm or less, there is a problem that the pressure difference becomes large in the surface of the sample to be processed when the high flow rate gas is introduced. This problem becomes noticeable as the sample diameter increases,
This is an essential issue in the next-generation processing of 300 mm or larger diameter wafers.

As described above, the prior art does not consider the relationship between the plasma diameter, the substrate diameter, the shower diameter and the electrode spacing, and the relationship between the radical generation and the wall consumption, so that the apparatus of a certain size is used. Even if the shower diameter that can obtain uniformity is determined by trial and error, if the scale is increased or the plasma distribution is changed by changing the chamber structure, the shower diameter will deviate from the optimum value and the etching rate and the substrate surface of the shape will change. There was a problem that unevenness occurred inside.

The object of the present invention is low power consumption and high uniformity even when the processing area of the sample to be processed is large, and
Another object of the present invention is to provide a plasma processing apparatus and a control method therefor, which are excellent in fine workability, can be processed with a high selection ratio and a high aspect ratio, and can be processed at a high speed. In particular,
It is to realize high etching performance by controlling etching radicals in plasma and plasma generation conditions independently and realizing highly accurate active species control. It is also an object of the present invention to maintain stable etching characteristics by stabilizing the composition of active species in plasma for a long period of time.

[0020]

A flat plate for introducing an electromagnetic wave for plasma generation is installed at a position facing a substrate, and a second high frequency is applied to the flat plate. Further, the distance between the flat plate and the substrate is set to 30 mm to 1/2 or less of the smaller diameter of the flat plate diameter and the substrate diameter. An electromagnetic wave of 300 MHz to 2.45 GHz is used for plasma generation, and the frequency of the second high frequency to be superimposed on this electromagnetic wave is 50 kHz to 3
0 MHz is used. Further, a ring-shaped or arc-shaped member (hereinafter referred to as a ring-shaped member) formed of a material such as silicon is arranged around the substrate, and a bias can be applied to this ring-shaped member. Furthermore, a function of controlling the temperature of the flat plate and the wall of the vacuum container, more preferably the annular member, is added.

With the above structure, high-density plasma can be formed with a low magnetic field, and fine processing can be performed at high speed. Also,
Since the second frequency is superimposed on the flat plate and the distance between the flat plate and the flat plate is set to 1/2 or less of the diameter of the smaller one of the flat plate and the flat plate, the radical species in the plasma can be controlled. It is possible to control the reaction on the surface with high accuracy. As a result, it becomes possible to carry out the plasma etching treatment which has both a high selection ratio and fine workability. Further, in the present invention, since the inner wall surface in contact with the plasma is in a state in which a bias is applied and the plasma reaction is continuously maintained, or the reaction is stabilized by temperature control,
It is possible to obtain stable etching treatment characteristics over a long period of time, as the etching conditions do not fluctuate as the etching treatment is repeated.

Further, a portion of the flat plate which is in contact with plasma is made of silicon, carbon, quartz or silicon carbide, and is mainly composed of a mixed gas of argon and a chlorofluorocarbon gas represented by C ₄ F ₈ or a hydrocarbon gas. By using the source gas, it is possible to process the silicon oxide film with high accuracy. Further, by using a raw material gas mainly containing chlorine, boron trichloride, hydrogen bromide, or a mixed gas thereof, it is possible to process a thin film of silicon, aluminum, tungsten or the like with high precision.

Further, the radical density distribution is determined by the plasma density distribution and the size of the radical attachment coefficient to the chamber wall surface. When radicals are consumed only by the substrate, Journal of Electrochemical Society (1989), Vol. 136, No. 6, 1781
As described from page 1 to page 1786, when the plasma diameter is larger than the substrate diameter, the amount of radicals increases on the outer peripheral side of the substrate, and as a result, the etching rate increases in the direction of increasing the radius of the substrate. When the plasma diameter is smaller than the substrate diameter, the amount of radicals on the outer circumference of the substrate decreases, and as a result, the etching rate decreases in the direction of increasing the radius of the substrate.

Therefore, the shower diameter is further set in consideration of the plasma diameter and the substrate diameter. That is, in order to solve the above problems, the diameter (shower diameter) of the region where the ejection holes of the shower plate for supplying the processing gas are present is 30% to 30% of the substrate diameter when the plasma diameter is spread over the entire chamber. It was set to 85%.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. 2, 3, 4, 5, and 6. Figure 1 is a book
It is sectional drawing of the etching apparatus which becomes one Example of invention .
2 is a sectional view taken along line AA of FIG. 3, 4, and 5,
FIG. 6 is an explanatory diagram showing the effect of the present embodiment. Here, the etching process will be described as an example, but the same applies to the CVD process. In FIG. 1, a substrate 4 is placed inside a chamber 1 on a second plate 3 arranged to face the first plate 2. The distance between the first plate 2 and the second plate 3 is set to 30 mm or more and half the maximum diameter of the substrate 4 or less. However, when the maximum diameter of the substrate 4 is 60 mm or less, the interval is 30 mm.

The substrate 4 in this embodiment is a silicon wafer having a diameter of 200 mm. The distance between the substrate 4 and the first plate 2 is 70
mm. An exhaust port 9 is provided on the outer periphery of the second plate 3, and the gas is exhausted by a vacuum pump (not shown). A coaxial cable 11 for supplying an electromagnetic wave of 450 MHz to the first plate 2
Is provided and is connected to a 450 MHz power supply (not shown). Here, this electromagnetic wave may have any frequency as long as it has a frequency of 300 MHz to 2.45 GHz. An electromagnetic wave of 450 MHz propagates between the chamber 1 and the coaxial cable 11, passes through the quartz block 12, and is introduced into the processing chamber 6. The space surrounded by the chamber 1, the coaxial cable 11, the first plate 2, and the quartz block 12 is filled with a dielectric 16 so that electromagnetic waves can easily propagate.

An electromagnetic coil 13 is installed outside the chamber 1 to generate a magnetic field. Electromagnetic wave frequency is 450MHz
In the case of, the magnetic field strength is 0.0161 Tesla (161 Gauss) and electron cyclotron resonance (ECR) occurs. In this way, the plasma 7 is generated in the processing chamber 6 between the first plate 2 and the second plate 3. RF (high frequency) auxiliary power supplies 5a and 5b are connected to the first plate 2 and the second plate 3, respectively, so that a bias voltage is loaded. The frequencies of the auxiliary power supplies 5a and 5b are
50 kHz to 30 MHz is used.

An annular member 10 is provided on the second plate 3 outside the substrate 4. As the material of the annular member 10, silicon or silicon carbide is used as a high-purity low-resistance material. A dielectric (not shown) is laid under the annular member 10. In addition, a part of the bias applied to the substrate 4 is divided by the capacitor 14 and supplied to the annular member 10, so that the bias is applied to the annular member 10. Further, a temperature control function 15 may be added immediately below the annular member 10 to control the temperature of the annular member 10.

As the material of the first plate 2, carbon, silicon or the like is used. A large number of gas holes 2a are opened in the central portion of the first plate 2 and are connected to the gas supply means 8 to form a so-called shower head. The shower head may be manufactured integrally with the first plate 2 or may be attached separately. The shower head is configured so that the diameter (shower diameter: Ds) of the region where the ejection holes 2a for supplying the processing gas to the first plate 2 are present is 50% to 85% of the substrate diameter (Dw). . In this embodiment, the diameter of the ejection hole is 0.5 mm. Here, the diameter (shower diameter: Ds) of the region where the ejection holes for supplying the processing gas are present is defined as the maximum diameter of the region where 98% or more of the flow rate of the reaction gas (for example, C4F8) is ejected.

As a plasma generating gas for etching, a mixed gas of argon and a fluorocarbon type gas such as CF4 or C4F8, Cl2, BCl3, SF6 or the like.
A gas such as HBr is used depending on the film to be etched. The pressure used in this embodiment is 0.5 to 20 P.
a, the flow rate is 100 to 2000 SCCM.

For example, assume that the patterned SiO 2 film is etched with a mixed gas of argon and a fluorocarbon-based gas such as CF 4 or C 4 F 8 as a plasma generating gas. Patterned SiO2
The resist film covers the surface except the place of the film. The base film is Si or Si3N4. This gas is supplied from the gas supply means 8 to the gas hole 2 of the shower head provided in the first plate 2.
When the gas is supplied to a, the gas flows from this hole to the processing chamber 6,
It is discharged from the exhaust port 9.

Next, when an electromagnetic wave of 450 MHz is supplied to the coaxial cable 11, the electromagnetic wave propagates between the chamber 1 and the coaxial cable 11, passes through the quartz block 12 and is introduced into the processing chamber 6, where resistance heating and ECR heating are performed. As a result, plasma is generated. This plasma is distributed throughout the processing chamber 6 from the space between the first plate 2 and the second plate 3 to the bottom of the quartz block 12, and the plasma diameter Dp is the inner diameter Dc of the chamber 1.
Is almost equal to. In this plasma, the gas is ionized and dissociated, ions and radicals are generated, these ions and radicals enter the substrate 4, and the substrate is etched.

Radicals that contribute to etching include
There are F, CF, CF2, CF3 and the like. Since F radicals generated in plasma have a high reaction rate with Si or Si3N4, the amount of F is reduced when it is necessary to increase the selection ratio with respect to Si or Si3N4 (scavenging action).
For this purpose, a bias voltage is applied to the silicon first plate 2 and the annular member 10. Then, since F reacts with the first plate 2 and the annular member 10 and is consumed, the concentration of F on the substrate 4 is reduced, but since there is no silicon electrode on the outer peripheral side wall of the chamber 1, the concentration of F in the processing chamber 6 is reduced. A region having a high F concentration is formed on the outer peripheral side.

On the other hand, CF-based radicals are formed on Si on the substrate.
The O2 film is etched by ion bombardment and adheres to the other wall to which the bias voltage is not applied, but does not adhere to the biased surface. The F radicals that have reacted with the resist release CF-based products into the processing chamber 6. Therefore, the concentration of CF-based radicals is likely to be high in the central portion of the substrate. On the other hand, the reaction products generated from the film to be etched tend to accumulate in the center of the substrate. Since this product adheres to the side wall of the etching hole and becomes a part of the protective film, it affects the etching shape. Annular member 10
Has the effect of consuming excess fluorine radicals in the peripheral portion of the sample to be processed due to surface reaction with fluorine and making the amount of F radicals incident on the substrate 4 somewhat uniform. Annular member 10
The surface reaction can be controlled by adjusting the amount of bias applied to the annular member 10.

In the embodiment shown in FIG. 1, the material of the annular member 10 is silicon in order to control the fluorine radicals, but carbon, silicon carbide, quartz, aluminum oxide, aluminum, etc. may be used as the activity to be controlled. Appropriate materials may be selected depending on the type of seed.

Here, if the distance between the first plate 2 and the second plate 3 (electrode distance) is 30 mm or more, the pressure difference in the substrate surface is small even at a low pressure of several Pascals, and the radicals due to the pressure difference are transferred to the substrate. Does not cause non-uniformity in the amount of incident light. This relationship is shown in Figure 3.
It was shown to. ± 5% etching rate uniformity in the substrate surface
In order to stay within the range, the pressure (or density) also needs to be within ± 5%. For this purpose, it can be seen that the electrode interval needs to be 30 mm or more. The area affected by the surface reaction depends on the size of the reaction surface and is almost the radius of the reaction surface.

Therefore, the distance between the substrate 4 and the first plate 2 at the position facing the substrate 4 is set to be equal to or less than the radius of the substrate 4 or the first plate 2.
By making the radius of the plate 2 or less, it is possible to strongly reflect the surface reaction occurring on the surfaces of the plates. Specifically, if the distance (electrode distance) between the first plate 2 and the second plate 3 is at least half the substrate diameter, the scavenging effect of the fluorine radicals on the surface of the first plate 2 becomes difficult to work.

Therefore, as shown in FIG. 4, the first plate 2 and the second plate 3 are
By setting the distance between and to less than half the diameter of the substrate, the scavenging effect of the fluorine radicals on the surface of the first plate 2 is effective, and the radical ratio CF2 / F or CF3 incident on the substrate is increased.
/ F increases, and the selection ratio of the SiO2 film to the Si3N4 film increases. Therefore, the distance between the first plate 2 and the substrate 4 is 30 mm to 1/2 of the substrate diameter (φ200 m).
Good characteristics can be obtained at 100 mm or less for m wafers and 150 mm or less for φ300 mm wafers. If the diameter of the first plate 2 is smaller than the diameter of the substrate,
The above interval may be set to 1/2 or less of the diameter of the first plate.

Further, FIG. 5 shows the relationship between the shower diameter and the radial distribution of the amount of fluorine radicals incident on the substrate surface, and FIG. 6 shows the relationship between the shower radius and the in-substrate uniformity of the Si3N4 film etching rate. . When the diameter Ds of the shower of the first plate 2 is set to 85% or more of the diameter Dw of the substrate, the source gas C4F8 has a high concentration in the region of the substrate diameter Dw or more, and thus dissociates to generate fluorine radicals, and the processing chamber 6
The concentration of fluorine radicals becomes high on the outer peripheral side, and the etching rate of the Si3N4 film (base film) on the surface of the substrate 4 becomes uneven. When the diameter Ds of the shower of the first plate 2 is set to 30% or less of the diameter Dw of the substrate, the flow velocity immediately below the shower increases, the concentration of generated fluorine radicals becomes non-uniform on the substrate, and the etching rate also becomes non-uniform. Become.

As described above, when the plasma spreads throughout the processing chamber and the plasma diameter is sufficiently larger than the substrate diameter,
The diameter Ds of the shower of the first plate 2 is 30 times the diameter Dw of the substrate.
% To 85%, the amount of fluorine radicals in the vicinity of the outer periphery of the substrate 4 can be made closer to the amount at the center of the substrate, and the etching rate distribution of the Si film or Si3N4 film (base film) of the substrate 4 is It has the effect of homogenizing inside.

That is, in the case of etching a SiO2 film having Si3N4 or Si as a base, there is an effect that uniformity of the selection ratio in the substrate surface can be obtained. Etching film is Si3N
In the case of 4, there is an effect that the etching rate uniformity of the film to be etched can be obtained. Further, by narrowing the shower diameter, the reaction product can be quickly exhausted from the processing chamber 6, and there is an effect of improving the etching rate. Also,
The reaction product accumulated near the center of the substrate is exhausted by the flow, and the incident distribution on the surface of the substrate becomes uniform, so that the etching shape is also uniform within the substrate.

In the plasma source as in this embodiment, when the ECR surface is on the outer peripheral side of the substrate due to the magnetic field to be set,
The plasma density may become higher on the outer peripheral side than the substrate.
When such a condition is used, the effect of the present invention is higher. In addition, the flow rate of gas flowing out from the ejection hole 2a of the shower head is changed for each ejection hole to distribute the flow rate in the radial direction or to distribute the concentration, so that the material gas C4F is substantially discharged.
The configuration in which the diameter of the region in which 98% of 8 flows out is set to 30% to 85% of the diameter Dw of the substrate has the same effect as the present invention, and belongs to the present invention.

Another embodiment of the present invention will be described with reference to FIG. Unlike the embodiment of FIG. 1, there is no electromagnetic coil 13. The method of introducing electromagnetic waves is the same as that of the first embodiment, but a spoke antenna or the like may be used. The electromagnetic wave is absorbed by the resistance heating mechanism in the plasma in the absence of magnetic field to generate plasma. This device is used in processes where plasma density may be low.
In this case, the structure of the device is simplified.

FIG. 8 is a sectional view of another embodiment of the present invention. A quartz block 12 having a shower head is provided on the surface of the first plate 2 facing the second plate 3. With respect to the above device configuration, the distance between the first plate 2 and the second plate 3 is set to 100 mm to 200 mm, and the shower head has a diameter of a region where ejection holes for supplying the processing gas to the first plate 2 are present ( Shower diameter) is 30% to 75% of substrate diameter
Configured to be%.

Such a device structure is applied to a device which does not like exposing the electrode (first plate 2) directly on the surface facing the substrate. Such a device is often used in a process of etching a silicon film or an aluminum film using chlorine Cl2 as an etching gas. Chlorine Cl2 is dissociated into chlorine radicals in plasma, and the reaction between the chlorine radicals and ions etches the silicon film or aluminum film on the substrate surface. If only one atomic layer of chlorine radicals is adsorbed on the wall surface of the chamber, it will not adhere to the wall surface and will be consumed only on the substrate surface.

Therefore, the concentration tends to increase on the outer peripheral side of the substrate as in the case of the fluorine radicals described above, but by setting the shower diameter to 30% to 75% of the substrate diameter, the chlorine radicals are incident on the substrate. There is an effect that the flux becomes uniform and the etching rate becomes uniform in the plane of the substrate. Unlike the first embodiment, there is no radical scavenging effect on the surface facing the substrate 4, and the height of the substrate 4 and the shower head is high. Therefore, the shower diameter is set smaller than that of the first embodiment. Further, in particular, such a configuration has an effect that the consumption of the electrode is suppressed and the life of the device is extended.

Another embodiment of the present invention is shown in FIGS.
Described in. FIG. 9 is a sectional view of a parallel plate type capacitively coupled plasma etching apparatus. FIG. 10 is a sectional view taken along line AA of FIG. Since such a device is used at a higher gas pressure than that of the first embodiment, it is not suitable for microfabrication, but is used for high-speed etching of a film that does not require microfabrication. In FIG. 9, the substrate 4 is placed on the second plate 3 which is arranged so as to face the first plate 2 provided in the chamber 1. A high frequency power source 5a is connected to the first plate 2 and a high frequency power source 5b is connected to the second plate 3. The frequency of the power supply is 4
00 MHz to several hundred MHz is used. Plasma 7 is generated in the processing chamber 6 between the first plate 2 and the second plate 3 by the high frequency power supplies 5a and 5b, and the substrate 4 is processed. A large number of gas holes 2a are opened in the central portion of the first plate 2 and are connected to the gas supply means 8 to form a so-called shower head.

An exhaust port 9 is provided on the outer periphery of the second plate 3. Carbon, silicon, or the like is used as the material of the first plate 2. A ring 15 is provided on the outer peripheral portion of the surface of the first plate 2 that faces the second plate 3. The material of the ring 15 is an insulator such as quartz. The ring 15 serves to limit the radial size of the plasma 7 generated by the discharge between the first plate 2 and the second plate 3. Here, the inner diameter of the ring 15 or the plasma diameter Dp is set to be larger than the diameter Dw of the substrate. Further, the radius (shower diameter) D of the region where the jet holes of the shower plate for supplying the processing gas are present.
A shower head was mounted so that s was 30% to 85% of the substrate diameter Dw. In this embodiment, the diameter of the wafer is 2
The inner diameter of the ring 15 is 310 mm and the shower diameter is 150 mm.

When high frequency power is applied to the first plate 2 and the second plate 3 to generate plasma 7, the plasma is generated by the first plate 2
The plasma spreads to the inside of the ring 15 between the second plate 3 and the second plate 3. That is, the diameter Dp of the plasma is the diameter D of the substrate.
It is considerably larger than w. Such a situation occurs when a small diameter substrate is processed by an apparatus capable of processing a large diameter substrate.

Here, when the shower diameter is almost the same as the diameter of the substrate, the F radicals are excessive on the outer periphery of the substrate, but the shower diameter is 30% to 8% of the substrate diameter as in the present embodiment.
When the shower head is set to 5%, the source gas is decomposed in the vicinity of the center of the processing chamber 6, so that F radicals are consumed by the substrate and the first plate 2 and have a uniform distribution on the substrate and the etching rate. The distribution becomes uniform on the substrate in the radial direction.

In FIG. 11, the plasma diameter Dp is the substrate diameter Dw.
The relationship between the shower radius and the etching rate uniformity is shown in the same case (conventional example) and the case where the plasma diameter Dp is larger than the substrate diameter Dw.

As described above, when the plasma diameter is close to the substrate diameter as in the conventional case, the etching rate uniformity is good when the shower diameter is close to the substrate diameter. When it is sufficiently larger, the shower diameter has high uniformity (for example, ± 5% or less) when it is 30% to 85% of the substrate diameter. With such a configuration, it is possible to obtain an apparatus having uniform etching characteristics for both large and small substrates by simply changing the shower diameter of the shower head, and it is possible to reduce the cost.

Another embodiment of the present invention will be described with reference to FIG. The plasma generation method is called an inductive coupling method. In FIG. 12, a dielectric wall 17 is provided in a part of the chamber 1, and a coil 18 is wound around the dielectric wall 17. A power source 5c is connected to the coil 18 and a high frequency (for example, 13.
(56 MHz), plasma 7 is generated by the induction heating mechanism. The first plate 2 facing the substrate 4 is made of silicon and has a shower head formed in the center thereof. The plasma 7 has a ring-shaped high density region as shown in FIG. 11, but since it diffuses and spreads throughout the processing chamber 6,
The distance between the first plate 2 and the substrate 4 and the shower diameter are set as in the first embodiment. With such a configuration, there is an effect that there is no damage to the processing of an element which is greatly damaged by a magnetic field and a high uniformity of the etching rate is obtained within the surface of the substrate.

The above is the embodiment of the UHF electromagnetic wave ECR plasma apparatus, the parallel plate capacitive coupling type plasma apparatus and the inductive coupling type plasma apparatus, but the present invention can be implemented in common to other plasma apparatuses. Further, it can also be applied to a plasma CVD apparatus or a thermal CVD apparatus.

In this way, with respect to the chamber height,
By controlling the radial distribution of radical density by setting the shower diameter in consideration of the substrate diameter and plasma diameter,
There is an effect that the etching rate distribution, the selection ratio, and the etching shape of the film to be etched, the resist film, and the base film on the substrate can be uniformly controlled in the plane of the substrate.

[0056]

According to the present invention, it is possible to perform etching in a state where the etching target film has a high selection ratio with respect to the underlying film or the resist film, and the etching rate distribution of the etching target film, the underlying film or the resist film is highly uniform. The processing accuracy can be improved, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a plasma processing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1 of the present invention.

FIG. 3 is an explanatory diagram of an effect of the present invention.

FIG. 4 is an explanatory diagram of an effect of the present invention.

FIG. 5 is an explanatory diagram of an effect of the present invention.

FIG. 6 is an explanatory diagram of an effect of the present invention.

FIG. 7 is a sectional view of a plasma processing apparatus according to another embodiment of the present invention.

FIG. 8 is a sectional view of a plasma processing apparatus according to another embodiment of the present invention.

FIG. 9 is a sectional view of a plasma processing apparatus according to another embodiment of the present invention.

10 is a sectional view taken along line AA of FIG. 9 of the present invention.

FIG. 11 is an explanatory diagram of an effect of the present invention.

FIG. 12 is a sectional view of a plasma processing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1: chamber, 2: first plate, 2a: gas hole, 3: second
Plate, 4: substrate, 5a, 5b, 5c: power supply, 6: processing chamber,
7: plasma, 8: gas supply means, 9: exhaust port, 10:
Annular member, 11: coaxial cable, 12: quartz window, 1
3: electromagnetic coil, 14: capacitor, 15: temperature control function, 16: dielectric, 17: dielectric wall, 18: coil.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-25586 (JP, A) JP-A-11-16888 (JP, A) JP-A-5-234954 (JP, A) JP-A-10- 150022 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/3065 H01L 21/205

Claims (7)

(57) [Claims] 1. A means for supplying a raw material gas, an evacuation means, a means for converting the raw material gas into plasma, and a sample to be processed.
A plasma treatment for converting the source gas into a plasma and subjecting the sample to be surface-treated in a vacuum container having a setting means having a sample mounting surface to be mounted and having a means for applying high-frequency power to the sample to be processed. In the apparatus, the plasma generating means is used to introduce an electromagnetic wave into the vacuum container, and the electromagnetic wave is introduced from a plane plate arranged parallel to and facing the sample to be processed, and high-density plasma is generated from the plane plate.
Means for generating a wider range and applying a bias voltage to the flat plate and sample mounting surface
The provided spacing the mounting surface the specimen and the plane plate is set lower than half the maximum diameter of該被processed sample at least 30 mm, a gas supply port comprising a plurality of holes for supplying a raw material gas in said plane plate Is provided
The plasma processing apparatus, wherein the effective diameter of the gas supply port is 30 to 85% of the maximum diameter of the sample to be processed. 2. A means for supplying a source gas, an evacuation means, a means for converting the source gas into a plasma, and a sample to be processed.
A plasma treatment for converting the source gas into a plasma and subjecting the sample to be surface-treated in a vacuum container having a setting means having a sample mounting surface to be mounted and having a means for applying high-frequency power to the sample to be processed. In the apparatus, the plasma generating means is of an inductive coupling type using an electromagnetic coil , and high-density plasma is generated between the sample to be processed and a flat plate arranged to face the sample to be processed in parallel. Wider than flat plate
It raises the stomach range, the spacing of the mounting surface the specimen and the plane plate is set lower than half the maximum diameter of該被processed sample at least 30 mm, composed of a plurality of holes for supplying a raw material gas in said plane plate A gas supply port is provided,
The plasma processing apparatus, wherein the effective diameter of the gas supply port is 30 to 85% of the maximum diameter of the sample to be processed. 3. A means for supplying a source gas, an evacuation means, a means for converting the source gas into plasma, and a sample to be processed.
A plasma treatment for converting the source gas into a plasma and subjecting the sample to be surface-treated in a vacuum container having a setting means having a sample mounting surface to be mounted and having a means for applying high-frequency power to the sample to be processed. In the apparatus, the plasma generating means is used to introduce an electromagnetic wave into the vacuum container, and the electromagnetic wave is introduced from an antenna installed on the back of a flat plate arranged in parallel and facing the sample to be processed. to generate density plasma over a wide range from the plane plate, the distance between the mounting surface the specimen and the plane plate set to 100 to 200 mm, the gas supply port comprising a plurality of holes for supplying a raw material gas in said plane plate And the effective diameter of the gas supply port is 30 to 75% of the maximum diameter of the sample to be processed. 4. A means for supplying a source gas, an evacuation means, a means for converting the source gas into plasma, and a sample to be processed.
A first plate having a sample mounting surface to be mounted, and in a vacuum container having means for applying high-frequency power to the sample to be processed,
In the plasma processing apparatus for surface treatment of plasma of the raw material gas該被processed sample, the plasma generating means by the introduction of high-frequency power, faces parallel to the introduction of the high-frequency power to the first plate and the first plate was performed and a second plate disposed, a gas supply port comprising a plurality of holes for supplying a raw material gas to the second plate is provided, the size of the effective diameter of the gas supply port of該被processed sample 30 to 85% of the maximum diameter, and the high frequency power applying means applies 100 k to the sample to be processed.
High-frequency power from Hz to 14MHz Unit surface of the sample to be processed
Those from the product per 0.5W / cm ² 8W / cm ² is applied
The plasma processing apparatus is characterized in that The plasma processing apparatus according to any one of claims 5] claims 1 to 4, the size of the effective diameter of the gas supply port, at least 98% of the total flow rate of the contributing source gas to the etching outflow A plasma processing apparatus having a diameter of a region to be processed. 6. The method for controlling a plasma processing apparatus according to claim 1, wherein the surface treatment of the sample to be processed is performed while uniformly controlling the distribution of the amount of fluorine radicals incident on the substrate. A method of controlling a plasma processing apparatus, comprising: 7. A method of controlling a plasma processing apparatus according to any one of claims 1 to 4, introducing a gas, generating a plasma, etching the substrate, comprising the step of removing the substrate A method of controlling a plasma processing apparatus, comprising: