JP2022188899A - Apparatus and method for treating substrate - Google Patents

Abstract

An object of the present invention is to provide a substrate processing apparatus that can uniformly perform surface modification treatment on an insulating film of silicon oxide or silicon nitride in a simple manner, and a substrate processing method using the apparatus. [Solution] (a) A cylindrical container made of an insulator, a gas supply port for supplying gas to the cylindrical container, and a microwave introduction port provided on the side of the cylindrical container. , (b) a reactive gas generation chamber for generating a cylindrical reactive gas; A substrate processing apparatus comprising: a holding table for holding the substrate so that the substrate to be processed is irradiated; and a substrate processing chamber equipped with a gas exhaust port for exhausting the gas, A distance L1 between the container and the substrate is 1 mm or more and 1000 mm or less, and the holding table is rotatably provided around a predetermined rotation axis R, and the rotation axis R and the cylindrical container are A substrate processing apparatus characterized in that the central axis C of the substrate processing apparatus is not on the same straight line as the center axis C of the substrate processing apparatus. [Selection diagram] Figure 1(a)

Description

The present invention relates to a substrate processing apparatus for modifying the surface of a substrate on which an insulating film such as a silicon oxide film or a silicon nitride film is formed, and a substrate processing method using the apparatus.

In semiconductor substrates, films such as silicon oxide and silicon nitride are widely used as insulating films and protective films. Silicon source gases such as monosilane (SiH ₄ ) and disilane (Si ₂ H ₆ ) and oxygen- or nitrogen-containing gases (nitrogen gas, ammonia, etc.) were used as a method for forming a silicon oxide film or a silicon nitride film. A plasma-enhanced chemical vapor deposition (CVD) method is known.

Silicon oxide films and silicon nitride films deposited by plasma CVD have Si-H bonds in the film because hydrogen is contained in monosilane gas and disilane gas, resulting in a low breakdown electric field. In some cases, deterioration of film properties such as

As a method of reducing the Si-H bonds in the film and modifying the surface of the insulating film, there is a method of surface treatment using microwave plasma. However, when the surface of a semiconductor substrate is irradiated with plasma, the film surface can be modified by the ions and electrons in the plasma, but if the energy is too high, the substrate film and elements will be damaged and the device performance will be degraded. There is a problem that

Patent Document 1 (Japanese Patent Application Laid-Open No. 2017-224669) discloses that a silicon nitride film formed on a substrate by plasma CVD is irradiated with microwave hydrogen plasma, and the surface of the silicon nitride film is treated by atomic hydrogen in the microwave plasma. A method for treating a silicon nitride film is disclosed that removes hydrogen from a portion and modifies the surface portion. In Cited Document 1, by adjusting the pressure when generating microwave hydrogen plasma to 10 to 100 Pa, it is possible to create a state where ion energy is low and a large amount of atomic hydrogen (hydrogen radicals) is included, It is stated that the plasma so generated can be used to remove H from the Si--H bonds without breaking the Si--N bonds.

However, the microwave plasma processing method described in Patent Document 1 uses an apparatus consisting of a horizontally held substrate and a disk-shaped microwave transmitting plate (dielectric) arranged parallel to the substrate. , A surface wave plasma generated by irradiating a disk-shaped microwave transmission plate (dielectric) with microwaves is diffused downward and irradiated to the substrate to modify the surface of the substrate. However, it is difficult to obtain a sufficiently high plasma density (radical density) at the time the substrate is irradiated. In addition, it is difficult to sufficiently increase the ratio of radical species to ion species in the plasma obtained by the method and apparatus described in Cited Document 1, and if an attempt is made to generate a large amount of radical species, the ion species concentration will be sufficiently reduced. may not be possible, and damage to the substrate may not be sufficiently suppressed. Therefore, there is a demand for a method of modifying a substrate with higher efficiency while suppressing damage to the substrate.

As a microwave plasma generator with a simple configuration, Patent Document 2 (Patent No. 3637397) discloses that a cylindrical double container made of a dielectric material is introduced with microwaves from the side, so that the cylindrical container has an infinite length. , a microwave plasma generator that eliminates the need for an impedance matching device by forming a dielectric line and suppressing reflection of introduced microwaves. The cylindrical microwave plasma generator described in Patent Document 2 has a high plasma density, can shorten the processing time, and is inexpensive due to its simple structure.

However, since the plasma generated by the cylindrical microwave plasma generator described in Patent Document 2 is cylindrical, it is difficult to uniformly irradiate the substrate, which is the object to be processed, and the substrate processing pattern is uneven. Become.

Japanese Patent Application Laid-Open No. 2017-224669 Patent No. 3637397

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a substrate processing apparatus and a substrate processing method using the same, which can perform surface modification treatment of an insulating film of silicon oxide or silicon nitride in a simple, uniform and efficient manner. to provide.

In view of the above object, the present inventors have found that when a high-density plasma is generated by a cylindrical microwave plasma generator while flowing hydrogen gas, the object to be processed is generated from the cylindrical microwave plasma generator. By optimizing the distance to the substrate, when the plasma reaches the substrate surface, most of the ionic active species (hydrogen ions, electrons, etc.) in the plasma can be deactivated or radicalized, and the plasma can be transformed into hydrogen. By optimizing the position and angle of irradiating the substrate with the cylindrical reactive gas generated from the cylindrical plasma, it is possible to create a cylindrical microwave plasma. The inventors have found that substrates can be processed uniformly even when a generator is used, and have arrived at the present invention.

That is, the substrate processing apparatus of the present invention includes (a) a cylindrical container made of an insulator;
a gas supply port for supplying gas to the tubular container;
a reactive gas generation chamber for generating a cylindrical reactive gas, comprising a microwave introduction port provided on the side of the cylindrical container;
(b) connected to the reactive gas generation chamber;
a holding table for holding the substrate so that the cylindrical reactive gas generated in the reactive gas generation chamber is irradiated onto the substrate, which is an object to be processed;
a substrate processing chamber provided with a gas exhaust port for exhausting the gas;
a distance L1 between the cylindrical container and the substrate is ₁ mm or more and 1000 mm or less;
The holding base is rotatable around a predetermined rotation axis R, and the rotation axis R and the central axis C of the cylindrical container are not on the same straight line.

In the substrate processing apparatus of the present invention, the distance L ₂ between the upper end of the cylindrical container and the substrate and the mean free path λ are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
is preferably satisfied.

In the substrate processing apparatus of the present invention, the density of radicals formed by the reactive gas is preferably 1×10 ¹⁴ /cm ³ or more on the substrate.

In the substrate processing apparatus of the present invention, the shape of the trajectory of the cylindrical reactive gas irradiated onto the holding table when the holding table is rotated once changes the shape of the trajectory of the substrate when the holding table is rotated once. It is preferable that the substrate and the cylindrical container are arranged so as to include the shape of the trajectory drawn by .

In the substrate processing apparatus of the present invention, when the holder is rotated once while the substrate is being irradiated with the cylindrical reactive gas, the integrated amount of the reactive gas irradiated onto the substrate is the largest. It is preferable that 0.5≦P _MIN /P _MAX ≦1, where P _MAX is the integrated amount at the minimum point and P _MIN is the integrated amount at the smallest point.

In the substrate processing apparatus of the present invention, the rotation axis R and the central axis C may form an angle of 0 to 60°.

In the substrate processing apparatus of the present invention, it is preferable that the gas supplied to the cylindrical container is hydrogen.

In the substrate processing apparatus of the present invention, the cylindrical reactive gas is preferably a reactive gas mainly composed of hydrogen radicals when the substrate is irradiated with the reactive gas.

In the substrate processing apparatus of the present invention, it is preferable that the substrate has an insulating film deposited by plasma CVD on its uppermost layer, and the surface of the insulating film is modified by irradiation with the hydrogen radicals.

In the substrate processing method of the present invention, gas is supplied to a cylindrical container made of an insulating material from a gas supply port provided in the cylindrical container, and a micrometer is provided on the side of the cylindrical container. introducing microwaves from a wave inlet to generate a tubular reactive gas inside the tubular container;
While supplying the cylindrical reactive gas to the substrate processing chamber connected to the cylindrical container and exhausting the gas from a gas exhaust port provided in the substrate processing chamber, holding the substrate in the substrate processing chamber A substrate processing method for subjecting a substrate, which is an object to be processed and held on a table, to surface processing of the substrate by irradiating the cylindrical reactive gas onto the substrate,
a distance L1 between the cylindrical container and the substrate is ₁ mm or more and 1000 mm or less;
The substrate processing, wherein the holding table is rotatably provided around a predetermined rotation axis R, and the rotation axis R and the central axis C of the cylindrical container are not on the same straight line. Method.

In the substrate processing method of the present invention, the distance L ₂ between the upper end of the cylindrical container and the substrate and the mean free path λ are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
is preferably satisfied.

In the substrate processing method of the present invention, the density of radicals formed by the reactive gas is preferably 1×10 ¹⁴ /cm ³ or more on the substrate.

In the substrate processing method of the present invention, the product of the irradiation time and the radical density when the reactive gas is irradiated for 1 to 20 minutes is 25×10 ¹⁴ min/cm ³ or more on the substrate. preferable.

In the substrate processing method of the present invention, the shape of the trajectory of the cylindrical reactive gas irradiated onto the holding table when the holding table is rotated once changes the shape of the trajectory of the substrate when the holding table is rotated once. It is preferable that the substrate and the cylindrical container are arranged so as to include the shape of the trajectory drawn by .

In the substrate processing method of the present invention, when the substrate is irradiated with the cylindrical reactive gas and the holding table is rotated once, the integrated amount of the reactive gas irradiated onto the substrate is the largest. It is preferable that 0.5≦P _MIN /P _MAX ≦1, where P _MAX is the integrated amount at the minimum point and P _MIN is the integrated amount at the smallest point.

In the substrate processing method of the present invention, the rotation axis R and the central axis C may form an angle of 0 to 60°.

In the substrate processing method of the present invention, it is preferable that the gas supplied to the cylindrical container is hydrogen.

In the substrate processing method of the present invention, the cylindrical reactive gas is preferably a reactive gas mainly composed of hydrogen radicals when the substrate is irradiated with the reactive gas.

In the substrate processing method of the present invention, it is preferable that the substrate has an insulating film deposited by plasma CVD as the uppermost layer, and the surface of the insulating film is modified by irradiation with the hydrogen radicals.

With the substrate processing apparatus and substrate processing method of the present invention, it is possible to simply, uniformly and efficiently perform the surface modification treatment of insulating films of silicon oxide or silicon nitride. preferred.

The present invention can be applied to insulating films such as a silicon oxide film, a silicon nitride film, and an aluminum oxide film because the surface of the insulating film is modified by irradiation with hydrogen radicals. In particular, it is suitable for a substrate having an insulating film in which many Si—H bonds are present, which is formed by plasma CVD as the uppermost layer.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross section which shows an example of the substrate processing apparatus of this invention. FIG. 1(a) is a cross-sectional view taken along line A-A of FIG. 1(a). It is a schematic cross section showing another example of the substrate processing apparatus of the present invention. FIG. 2(a) is a cross-sectional view taken along line B-B of FIG. 2(a). FIG. 1(a) is a schematic cross-sectional view showing the shape of a reactive gas on the AA cross section of FIG. 1(a). FIG. 3 is a schematic diagram showing an example of the shape of reactive gas irradiated onto a substrate; FIG. 4 is a schematic diagram showing another example of the shape of the reactive gas irradiated onto the substrate; FIG. 10 is a schematic diagram showing still another example of the shape of the reactive gas irradiated onto the substrate; FIG. 10 is a schematic diagram showing still another example of the shape of the reactive gas irradiated onto the substrate; FIG. 10 is a schematic diagram showing still another example of the shape of the reactive gas irradiated onto the substrate; FIG. 4 is a schematic cross-sectional view showing still another example of the substrate processing apparatus of the present invention; 6 is a schematic diagram showing the shape of a reactive gas irradiated onto a substrate when the substrate processing apparatus shown in FIG. 5 is used; FIG. FIG. 10 is a schematic diagram showing the shape of the reactive gas irradiated onto the substrate when the cross-sectional shape of the cylindrical container is changed. FIG. 10 is a schematic diagram showing the shape of the reactive gas irradiated onto the substrate when the cross-sectional shape of the cylindrical container is changed. FIG. 10 is a schematic diagram showing the shape of the reactive gas irradiated onto the substrate when the cross-sectional shape of the cylindrical container is changed. FIG. 4 is a schematic cross-sectional view showing still another example of the substrate processing apparatus of the present invention; FIG. 10 is a schematic diagram showing the shape of a reactive gas irradiated onto a substrate when the substrate processing apparatus shown in FIG. 9 is used; FIG. 10 is a schematic diagram showing the shape of the reactive gas irradiated onto the substrate when the cross-sectional shape and number of cylindrical containers are changed. FIG. 10 is a schematic diagram showing the shape of the reactive gas irradiated onto the substrate when the cross-sectional shape and number of cylindrical containers are changed.

[1] Substrate Processing Apparatus FIGS. 1(a) and 1(b) show an example of a substrate processing apparatus 100 of the present invention. _A substrate processing apparatus 100 of the present invention comprises a reactive gas generation chamber 101 for generating a cylindrical reactive gas GA and a substrate processing chamber 102 connected thereto. a cylindrical container 103, a gas supply port 104 for supplying gas G to the cylindrical container 103, and a microwave introduction port 105 provided on the side of the cylindrical container 103, and the substrate processing chamber 102 is , a holder 107 for holding the substrate 106 so that the cylindrical reactive gas G _A generated in the reactive gas generation chamber 101 is irradiated onto the substrate 106, which is an object to be processed, and a gas exhaust for exhausting the gas G. and a port 108, the distance L1 between the cylindrical container 103 and the substrate 106 is ₁ mm or more and 1000 mm or less, and the holding base 107 is rotatably provided around a predetermined rotation axis R. , the rotation axis R and the central axis C of the cylindrical container 103 are not on the same straight line.

Note that the substrate processing apparatus 100 shown in FIGS. 1(a) and 1(b) is an example in which the cylindrical container 103 has a single layer structure, and the substrate processing apparatus 100 is shown in FIGS. 2(a) and 2(b). Thus, the cylindrical container 103 may have a double structure consisting of the inner container 103a and the outer container 103b arranged concentrically outside the inner container 103a. Such a double structure container makes it possible to easily supply a microwave plasma generator that does not require an impedance matching device. For example, the microwave plasma device described in Patent Document 2 can be used as the microwave plasma device composed of a double-structured tubular container.

The position where the gas exhaust port 108 is provided is not particularly limited, but it is preferably provided on the downstream side of the holding table 107 , that is, behind the holding table 107 when viewed from the reactive gas generation chamber 101 . In particular, it is preferable to provide it on the opposite side of the holding table 107 to the side where the substrate 106 is arranged.

(1) Properties of Reactive Gas In the reactive gas generation chamber 101 of the substrate processing apparatus 100, a cylindrical container 103 made of an insulating material is kept under reduced pressure. When a microwave is introduced from the microwave inlet 105 while supplying a gas G (for example, hydrogen gas) from the container 103, the microwave generates a standing wave with the surface of the cylindrical container 103 as a transmission path. Plasma of the gas G is generated in the tubular container 103 by the transmitted microwave. Since the plasma is generated along the inner wall of the cylindrical container 103, it has a cylindrical shape. In this way, by making the container 103 cylindrical, the microwave density in the standing wave portion becomes high, and as a result, the density of the plasma generated by the microwaves leaking inside the cylindrical container 103 is peculiar. relatively high. In the example shown in FIG. 1(a), the gas supply ports 104 are provided at two locations, but may be provided at one location or at three or more locations. If a plurality of gas supply ports 104 are to be received, they are preferably arranged along the position of the plasma generated in cylindrical container 103, that is, along the inner wall of the cylindrical container. Further, it is preferable to provide gas flow rate measuring means upstream of the gas supply port 104 .

The plasma generated here is in a state in which the molecules of the gas G are ionized. For example, when hydrogen gas is used as the gas G, it contains chemical species such as hydrogen ions and electrons. Here, the ionic species recombine with electrons and are deactivated in a relatively short period of time to generate gas G or gas G radicals. In the case of hydrogen gas, in the generated plasma, hydrogen ions decrease and hydrogen radicals increase over time. Especially under reduced pressure, the generated radicals have less chance of colliding with other radicals, so they exist for a relatively long time. Thus, a gas containing radicals generated by plasma, that is, a gas containing ions, electrons, and radicals is defined as a reactive gas _GA in the present application. The reactive gas G _A also becomes cylindrical like the plasma. For example, when the tubular container 103 is cylindrical, the reactive gas G _A has a ring shape having an outer shape substantially equal to the inner wall of the tubular container 103 when viewed in the axial direction (flow direction of the gas G).

The cylindrical reactive gas G _A generated in the reactive gas generation chamber 101 moves to the substrate processing chamber 102 provided in communication with the reactive gas generation chamber 101 according to the flow of the gas G supplied. At this time, chemical species such as ions, electrons, radicals, etc., flow through the gas G and at the same time spread due to diffusion, the cylindrical reactive gas G _A gradually becomes thicker with time. In addition, as described above, ions and electrons are quickly deactivated, so that ion species decrease and radical species increase with the passage of time.

The reactive gas G _A mainly composed of radical species is irradiated onto the substrate 106 held on the holding table 107 provided rotatably around the predetermined rotation axis R, and the insulating film provided on the surface of the substrate 106 is irradiated. (not shown) is subjected to surface modification. At this time, if there are many ions and electrons in the reactive gas _GA , the energy of the reactive gas is too high, which will damage the substrate film and elements. In order to increase the concentration of radical species effective for modifying the surface of the insulating film, the distance L1 between cylindrical container 103 and substrate 106 is set to ₁ mm or more and 1000 mm or less. By satisfying these conditions, for example, when hydrogen gas is used as the gas, the reactive gas _GA mainly composed of hydrogen radicals can be obtained when the substrate 106 is irradiated.

Here, the distance L ₁ between the cylindrical container 103 and the substrate 106 is the distance from the closest point of the cylindrical container 103 to the substrate 106 to the substrate 106 . For example, in the embodiment shown in FIG. ₁ (a), it is the distance L1 from the lower end 103-2 of the cylindrical container 103 to the surface 106a of the substrate 106. As shown in FIG. If the distance L1 is less than ₁ mm, there are many chemical species of ions and electrons, which damage the substrate film and elements. If the distance L ₁ exceeds 1000 mm, the radical species are deactivated by diffusion or recombination, making it impossible to ensure a sufficient concentration for modifying the substrate surface. _The lower limit of distance L1 between cylindrical container 103 and substrate 106 is preferably 5 mm, more preferably 10 mm. The _upper limit of the distance L1 between the cylindrical container 103 and the substrate 106 is preferably 500 mm, more preferably 300 mm.

Furthermore, the distance L ₂ between the upper end 103-1 of the cylindrical container 103 and the substrate 106 and the mean free path λ are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
is preferably satisfied. By satisfying this condition, when the substrate 106 is irradiated with the reactive gas _GA , chemical species such as ions and electrons in the reactive gas _GA are deactivated to some extent, which is effective for surface modification of the insulating film. The concentration of radical species can be increased.

While ions (ions of gas molecules) in the reactive gas G _A fly on the order of the mean free path, it is generally considered that those that collide with electrons collide and become radicals. If the distance L2 is shorter _than 0.1 times the mean free path of the ions of the gas molecules, the probability that they will become radicals before reaching the substrate is low, and the reactive gas _GA mainly composed of radicals cannot be obtained. Further, if the distance L2 is longer _than 100 times the mean free path λ of the gas molecules, the generated radicals collide with each other further and the radicals are deactivated. The mean free path referred to here is the mean free path until an ion of a gas molecule collides with an ion of another gas molecule. _The relationship between the distance L2 and the mean free path λ of ions of gas molecules is _more preferably 0.2×λ≦L2≦50×λ, most preferably 0.5×λ≦L2 _≦ 30×λ. preferable.

For example, when hydrogen gas is used as the gas, when the distance L ₂ and the mean free path λ of hydrogen ions satisfy the conditions of the above formula, the reactive gas mainly composed of hydrogen radicals is emitted to the substrate 106. It can be _GA . The mean free path λ of hydrogen ions is calculated to be 64 mm under a pressure of ₁₀ Pa when the particle diameter of hydrogen ions is 0.038 nm. Here, the reactive gas _GA mainly composed of hydrogen radicals is a reactive gas _GA in which the concentration of hydrogen radicals is higher than that of hydrogen ions.

The ratio (L ₂ /L ₁ ) between the distance L ₁ between cylindrical container 103 and substrate 106 and the distance L ₂ between upper end 103-1 of cylindrical container 103 and substrate 106 is 2 or more. Preferably, it is 2.5 or more, and most preferably 3 or more. By increasing this ratio (L ₂ /L ₁ ), it is possible to increase the amount of reactive gas generated, and to exhibit the effect of facilitating the spread of the reactive gas over the entire substrate.

Further, at the connecting portion between the reactive gas generation chamber 101 and the substrate processing chamber 102, the opening diameter of the opening where the substrate processing chamber 102 opens to the reactive gas generation chamber 101 is equal to the opening diameter (2r) of the cylindrical container 103. is preferably greater than By making the opening 102a of the substrate processing chamber 102 larger than the diameter of the opening of the cylindrical container 103 in this way, the members constituting the substrate processing chamber 102 are not directly exposed to the reactive gas or plasma gas. Damage caused by these gases can be reduced. A similar effect can also be achieved by forming the opening of the reactive gas generation chamber 101 with an insulator.

By configuring the relationship between the cylindrical container 103 and the substrate 106 as described above, the surface of the substrate 106 has a density of 1×10 ¹⁴ pieces/cm ³ or more, preferably 1×10 ¹⁵ pieces/cm ³ . The reactive gas G _A containing the above radicals can be irradiated. At this time, it is preferable that the holding table 107 is provided with heat retaining means or cooling means so that the temperature of the substrate 106 can be kept constant within the range of 0 to 400.degree.

(2) Relationship between cylindrical container and substrate
(a) When the rotation axis R and the central axis C are arranged in parallel Since the reactive gas G _A is cylindrical, when the reactive gas G _A is viewed from the gas supply port 104 side toward the substrate , the concentration is low in the central portion and the concentration is high near the inner wall of the cylindrical container. For example, as shown in FIGS. 1(a) and 1(b), when a device having a cylindrical container is used, the shape of the reactive gas G _A in the AA cross section is a ring shape as shown in FIG. becomes. The reactive gas G _A diffuses in the direction perpendicular to the axis, and basically irradiates the substrate surface while maintaining such a ring shape in cross section. Therefore, when the holder 107 and the cylindrical container 103 are arranged so that the rotation axis R of the holder 107 coincides with the central axis C of the cylindrical container 103, the cylindrical container 103 rotates around the central axis C. Since there is almost no reactive gas _{G A} in the substrate 106, as shown in FIG. I can't. Therefore, the rotation axis R of the holding table 107 and the central axis C of the tubular container 103 are shifted so as not to be on the same straight line. By shifting the rotation axis R and the central axis _C , for example, as shown in FIG. Since the substrate 106 is rotated around the rotation axis R, the substrate 106 is entirely irradiated with the reactive gas _GA .

The shape of the trajectory of the cylindrical reactive gas G _A irradiated onto the holding table 107 when the holding table 107 is rotated once includes the shape of the trajectory drawn by the substrate 106 when the holding table 107 is rotated once. It is preferable that the substrate 106 and the cylindrical container 103 are arranged as shown. Below, the relationship between the circular substrate 106 and the reactive gas G _A having a ring-shaped cross section will be described when the substrate 106 is arranged so that the center of the substrate 106 coincides with the rotation axis R of the holding table 107. do. Here, since the center of the substrate 106 is aligned with the rotation axis R of the holding table 107, the shape of the trajectory drawn by the substrate 106 when the holding table 107 is rotated once is the circular shape of the substrate 106 itself.

Since the reactive gas G _A having a ring-shaped cross section has a radius substantially the same as the radius r of the cylindrical container 103, the shape of the trajectory of the cylindrical reactive gas G _A described above is the same as that of the substrate 106. In order to include the shape of the locus to be drawn (here, the shape of the substrate 106), as shown in FIG. d satisfies d≦r, and the radius r _s of the substrate 106 satisfies r _s ≦2r. When d>r, as shown in FIG. 4(c), the reactive gas G _A is not irradiated around the central axis R of the substrate 106, and d≦r is satisfied, but r _s >2r. 4(d), the edge portion of the substrate 106 is no longer irradiated with the reactive gas _GA .

The larger the radius of the reactive gas G _A , that is, the radius r of the tubular container 103, the easier it is to satisfy d≦r and r _s ≦2r. However, as shown in FIG. 4(e), the amount of reactive gas G _A that is irradiated to the portion other than the substrate 106 only increases, so the radius r of the cylindrical container 103 is d≦r≦1.2×d and r _s ≦2r≦1.2×r _s and most preferably d=r and r _s =2r.

(b) When the rotation axis R and the central axis C are arranged at an angle It may be arranged at an angle of °. For example, as in the substrate processing apparatus 200 shown in FIG. Since the shape of the reactive gas G _A expands in the direction of inclination, a wider range can be irradiated with the reactive gas G _A. When the cylindrical container 103 is used, as shown in FIG. 6, the reactive gas G _A irradiated onto the substrate ₁₀₆ has an elliptical shape. However, it is possible to irradiate the reactive gas G _A to the central portion of the substrate 106 (the rotation axis R in the drawing) and the edge portion of the substrate 106 . The angle between the rotation axis R and the central axis C is more preferably 5-50°, most preferably 10-40°. If the angle is too small, the distribution is unfavorable. If it is too large, the ratio of non-irradiation to the substrate increases, which is not preferable.

(c) Uniformity of Reactive Gas In order to efficiently modify the surface of the substrate 106, the size of the cylindrical container 103 is such that the generated reactive gas G _A is irradiated onto the substrate 106 as uniformly as possible. (diameter, etc.), the distance to the substrate 106, the angle with respect to the substrate 106, etc. are preferably set. The amount of the reactive gas G _A that is actually applied to the surface of the substrate 106 is the amount that is integrated when the holding base 107 is rotated once while the substrate 106 is being irradiated with the cylindrical reactive gas G _A. . Here, when P _MAX is the integrated amount at the point where the integrated amount of the reactive gas G _A irradiated onto the substrate 106 is the largest, and P _MIN is the integrated amount at the point where it is the smallest, 0.5≦P _MIN /P _MAX ≤1 is preferred. That is, it is preferable that the irradiation amount P _MIN at the point where the irradiation amount of the reactive gas _GA is the smallest on the substrate 106 is 50% or more of the irradiation amount P _MAX at the point where the irradiation amount is the largest. The lower limit of P _MIN /P _MAX is more preferably 0.6, still more preferably 0.7, and most preferably 0.8.

In order to make the reactive gas G _A irradiated onto the substrate 106 as uniform as possible, that is, to maximize the value of P _MIN /P _MAX , the size (diameter, etc.) of the cylindrical container 103 is adjusted as described above. ), the distance to the substrate 106, and the angle with respect to the substrate 106 are preferably set. The cylindrical container 103 shown in FIGS. 1(a) and 1(b) has a cylindrical shape, but the cylindrical container 103 is not limited to a cylindrical shape. It may be in the form of For example, using a cylindrical container in which the reactive gas G _A irradiated onto the surface of the substrate 106 has a triangular-based shape as shown in FIGS. 7(a) to 7(c). Also good.

Furthermore, as in the substrate processing apparatus 300 shown in FIG. 8, a configuration in which two cylindrical containers 103 are arranged to be inclined with respect to the substrates is also effective. When this apparatus is used, the reactive gas G _A irradiated onto the surface of the substrate 106 has a spectacle shape as shown in FIG.

Also, the shape of the reactive gas G _A irradiated onto the surface of the substrate 106 was set to a shape based on two large and small rings and two large and small triangles shown in FIGS. 10(a) and 10(b). A configuration in which two cylindrical or triangular tubular containers with different heights are arranged is also effective.

[2] Substrate processing method A substrate processing method of the present invention includes a substrate processing apparatus (for example, shown in Figs. device). That is, in the substrate processing method of the present invention, a cylindrical container 103 made of an insulating material is supplied with a gas G from a gas supply port 104 provided in the cylindrical container 103, and a gas is supplied to the side of the cylindrical container 103. Microwaves M are introduced from a microwave introduction port 105 provided in the substrate processing chamber 102 to generate a cylindrical reactive gas _GA inside a cylindrical container 103, and connected to the reactive gas generation chamber 101. While supplying a cylindrical reactive gas G _A to the substrate processing chamber 102 and exhausting the gas from a gas exhaust port 108 provided in the substrate processing chamber 102, the object to be processed is held on the holding table 107 in the substrate processing chamber 102. _A method of surface-treating a substrate by irradiating the substrate 106 with a tubular reactive gas GA, comprising:
the distance between cylindrical container 103 and substrate 106 is 1 mm or more and 1000 mm or less,
The holding base 107 is rotatably provided around a predetermined rotation axis R, and the rotation axis R and the central axis C of the cylindrical container 103 are not on the same straight line (Fig. 1). (a) and Figure 1(b)).

Irradiation of the reactive gas G _A is performed, for example, by supplying hydrogen gas at a flow rate of 30 sccm from the gas supply port 104 to the cylindrical container 103 maintained at a pressure of 5 to 50 Pa, and A microwave M of MHz and 800 W/cm ² is introduced, and a cylindrical reactive gas G _A is generated inside the cylindrical container 103 by the microwave in a standing wave state in the cylindrical container 103, The substrate 106 kept at 0 to 400° C. is irradiated with a reactive gas _GA containing radicals with a density of 5×10 ¹⁴ /cm ³ or more for 1 to 20 minutes while rotating the holding table 107 . As a result, the product of the irradiation time and the density of radicals on the substrate 106 can be 25×10 ¹⁴ minutes/cm ³ or more. The potential difference between the reactive gas G _A and the surface of the substrate 106 is preferably 10 V or less. The post-processed reactive gas G _A and surplus hydrogen gas are exhausted from the gas exhaust port 108 . Radical irradiation density can be determined by a known method (T. Arai el al. (2016) "Selective Heating of Transition Metal Usings Hydrogen Plasma and Its Application to Formation of Nickel Silicide Electrodes for Silicon Ultralarge-Scale Integration Devices" Journal of Materials Science and Chemical Engineering, 2016, 4, 29-33).

As the gas, hydrogen gas is used from the viewpoint of generating hydrogen radicals, but it may contain other components than hydrogen gas. Components other than hydrogen gas include nitrogen, oxygen, carbon dioxide, ammonia, and rare gases (helium, neon, argon, etc.). As the tubular container 103, for example, a dielectric tube made of quartz can be used. The holding base 107 is rotatably held and is capable of adjusting the temperature.

A pressure of 5 to 50 Pa is preferably maintained inside the cylindrical container 103 . By keeping the inside of the cylindrical container 103 at 5 Pa or more, the potential difference between the reactive gas G _A and the substrate 106 can be easily reduced to 10 V or less, and the damage caused to the substrate 106 by the ionic active species is reduced. can be suppressed. By keeping the inside of the cylindrical container 103 at 50 Pa or less, the mean free path of the hydrogen radicals can be kept relatively long, and the generated hydrogen radicals can be effectively used to efficiently perform the surface treatment of the substrate 106. can be done.

The gas supply rate is preferably 0.01 to 1000 sccm. More preferably 0.05 to 200 sccm, more preferably 0.1 to 100 sccm. If the gas supply rate is less than 0.01 sccm, the reactive gas concentration will not increase, and if it is greater than 1000 sccm, exhaust will not occur and the pressure will become unstable.

The gas exhaust rate is preferably 1 to 10000 L/min. More preferably 10 to 2000 L/min, still more preferably 50 to 1000 L/min. If the gas pumping speed is less than 1 L/min, the pumping takes a long time, and if it is more than 10000 L/min, the cost is too high.

The microwave power is preferably 1 to 50000 W/cm ² . It is more preferably 5 to 5000 W/cm ² and even more preferably 10 to 500 W/cm ² . Below 1 W/cm ² the reactive gas production is low and above 50000 W/cm ² is too costly.

The treatment time is preferably 0.001 to 100 minutes. More preferably 0.01 to 50 minutes, still more preferably 0.05 to 20 minutes. If the treatment time is shorter than 0.001 minutes, the effect will be reduced, and if it is longer than 100 minutes, the productivity will deteriorate.

The rotation speed of the holding table 107 is preferably 0.1 to 10000 rpm. More preferably 1 to 1000 rpm, still more preferably 10 to 200 rpm. If the rotational speed is slower than 0.1 rpm, unevenness will occur, and if it is faster than 10000 rpm, the mechanical durability will be reduced.

When a substrate 106 having an insulating film made of silicon oxide deposited by plasma CVD as the uppermost layer is used as the object to be processed, the reactive gas G _A mainly composed of hydrogen radicals (H*) causes Si--H bonds and Si--OH bonds present in the silicon oxide film are reduced, Si--O--Si bonds are increased, and a high-density silicon oxide film can be obtained (see the reaction formula below).
<Reaction formula>
Si-H + H* → Si- ₊ H2,
Si-OH + H* → Si-O- ₊ H2, and
Si- + Si-O- → Si-O-Si
By forming a silicon oxide film having a high density of SiO ₂ in this manner, an insulating film having high insulating properties can be obtained.

The present invention will be explained in more detail by the following examples, but the invention is not limited thereto.

Example 1
The apparatus shown in FIG. 2 was used to modify the SiO ₂ insulating film formed on the substrate 106 made of a semiconductor. This SiO ₂ insulating film was formed by plasma CVD using monosilane gas and nitrogen gas, and had a thickness of 20 nm and a dielectric breakdown electric field strength of 1 MV/cm or less. In this apparatus, the cylindrical container 103 has a double structure consisting of an inner container 103a made of quartz and an outer container 103b made of quartz arranged concentrically outside the inner container 103a. The inner diameter was 50 mm, and the outer container 103b had an inner diameter of 100 mm. The distance L1 between the cylindrical container 103 and the substrate ₁₀₆ was 50 mm, and the distance L2 between the upper end 103-1 of the cylindrical container 103 and the substrate 106 was ₂₅₀ mm.

Irradiation of the reactive gas G _A was carried out at 2450 MHz and 800 W from the microwave inlet 105 while supplying hydrogen gas at a flow rate of 10 sccm from the gas supply port 104 to the tubular container 103 maintained at a pressure of 20 Pa. /cm ² microwaves M are introduced, and the microwaves are in a standing wave state in the cylindrical container 103 to generate a cylindrical reactive gas G _A inside the cylindrical container 103, The held substrate 106 was irradiated with a reactive gas _GA containing hydrogen radicals having a density of 5×10 ¹⁴ /cm ³ or more for 5 minutes while rotating the holding table 107 at 30 rpm. As a result, the product of the irradiation time and the density of hydrogen radicals on the substrate 106 was 25×10 ¹⁴ min·pieces/cm ³ or more.

As described above, the SiO ₂ insulating film formed by plasma CVD is modified by irradiating the reactive gas _GA containing hydrogen radicals, and the dielectric breakdown electric field strength is 7 MV/cm. A good insulating film was obtained.

100・・・Substrate processing equipment
101 Reactive gas generation chamber
102 Substrate processing chamber
103 Cylindrical container
103-1・・・Top end
103-2・・・Lower end
C・・・Center axis
106a surface
103a Inner container
103b... Outer container
104 Gas supply port
105 Microwave inlet
106 Substrate
106a surface
107 Holding table
R・・・Rotating axis
108 Gas exhaust port
G gas
G _A Reactive gas

Furthermore, the distance L ₂ between the upper end 103-1 of the cylindrical container 103 and the substrate 106 and the mean free path λ of the ions in the reactive gas _GA are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
is preferably satisfied. By satisfying this condition, when the substrate 106 is irradiated with the reactive gas _GA , chemical species such as ions and electrons in the reactive gas _GA are deactivated to some extent, which is effective for surface modification of the insulating film. The concentration of radical species can be increased.

Claims (19)

(a) a tubular container made of an insulating material;
a gas supply port for supplying gas to the tubular container;
a reactive gas generation chamber for generating a cylindrical reactive gas, comprising a microwave introduction port provided on the side of the cylindrical container;
(b) connected to the reactive gas generation chamber;
a holding table for holding the substrate so that the cylindrical reactive gas generated in the reactive gas generation chamber is irradiated onto the substrate, which is an object to be processed;
and a substrate processing chamber having a gas exhaust port for exhausting the gas,
a distance L1 between the cylindrical container and the substrate is ₁ mm or more and 1000 mm or less;
The substrate processing, wherein the holding table is rotatably provided around a predetermined rotation axis R, and the rotation axis R and the central axis C of the cylindrical container are not on the same straight line. Device. In the substrate processing apparatus according to claim 1,
The distance L ₂ between the upper end of the cylindrical container and the substrate and the mean free path λ of the ions of the gas molecules are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
A substrate processing apparatus characterized by: In the substrate processing apparatus according to claim 1 or 2,
A substrate processing apparatus, wherein the density of radicals formed by the reactive gas is 1×10 ¹⁴ /cm ³ or more on the substrate. In the substrate processing apparatus according to any one of claims 1 to 3,
The shape of the trajectory of the tubular reactive gas irradiated to the holding table when the holding table is rotated once includes the shape of the trajectory drawn by the substrate when the holding table is rotated once. A substrate processing apparatus, wherein the substrate and the cylindrical container are arranged in the . In the substrate processing apparatus according to any one of claims 1 to 4,
P _MAX is the integrated amount of the reactive gas at the point where the integrated amount of the reactive gas irradiated to the substrate is the largest when the holding table is rotated once while the substrate is irradiated with the cylindrical reactive gas, A substrate processing apparatus, wherein 0.5≦P _MIN /P _MAX ≦1, where P _MIN is the integrated amount at the smallest point. In the substrate processing apparatus according to any one of claims 1 to 5,
A substrate processing apparatus, wherein the rotation axis R and the central axis C form an angle of 0 to 60°. In the substrate processing apparatus according to any one of claims 1 to 6,
A substrate processing apparatus, wherein the gas supplied to the cylindrical container is hydrogen. In the substrate processing apparatus according to claim 7,
The substrate processing apparatus according to claim 1, wherein the tubular reactive gas is a reactive gas mainly composed of hydrogen radicals when the substrate is irradiated with the reactive gas. In the substrate processing apparatus according to claim 8,
1. A substrate processing apparatus according to claim 1, wherein the substrate has an insulating film formed by plasma CVD as an uppermost layer, and the surface of the insulating film is modified by irradiation with the hydrogen radicals. Gas is supplied to a cylindrical container made of an insulator from a gas supply port provided in the cylindrical container, and microwaves are introduced from a microwave inlet provided on the side of the cylindrical container. , generating a tubular reactive gas inside the tubular container;
While supplying the cylindrical reactive gas to the substrate processing chamber connected to the cylindrical container and exhausting the gas from a gas exhaust port provided in the substrate processing chamber, holding the substrate in the substrate processing chamber A substrate processing method for subjecting a substrate, which is an object to be processed and held on a table, to surface processing of the substrate by irradiating the cylindrical reactive gas onto the substrate,
a distance L1 between the cylindrical container and the substrate is ₁ mm or more and 1000 mm or less;
The substrate processing, wherein the holding table is rotatably provided around a predetermined rotation axis R, and the rotation axis R and the central axis C of the cylindrical container are not on the same straight line. Method. In the substrate processing method according to claim 10,
The distance L ₂ between the upper end of the cylindrical container and the substrate and the mean free path λ are expressed by the formula:
0.1×λ≦L2 _≦ 100×λ
[However, L ₂ is greater than the distance between the upper end and the lower end of the tubular container (L ₂ −L ₁ )+1 mm. ]
A substrate processing method characterized by satisfying In the substrate processing method according to claim 10 or 11,
A substrate processing method, wherein the density of radicals formed by the reactive gas is 1×10 ¹⁴ /cm ³ or more on the substrate. In the substrate processing method according to any one of claims 10 to 12,
A substrate processing method, wherein the product of the irradiation time and the density of radicals when the reactive gas is irradiated for 1 to 20 minutes is 25×10 ¹⁴ min/cm ³ or more on the substrate. In the substrate processing method according to any one of claims 10 to 13,
The shape of the trajectory of the tubular reactive gas irradiated to the holding table when the holding table is rotated once includes the shape of the trajectory drawn by the substrate when the holding table is rotated once. A substrate processing method, wherein the substrate and the cylindrical container are arranged in a container. In the substrate processing method according to any one of claims 10 to 14,
P _MAX is the integrated amount of the reactive gas at the point where the integrated amount of the reactive gas irradiated to the substrate is the largest when the holding table is rotated once while the substrate is irradiated with the cylindrical reactive gas, A substrate processing method, wherein 0.5≦P _MIN /P _MAX ≦1, where P _MIN is the integrated amount at the smallest point. In the substrate processing method according to any one of claims 10 to 15,
A substrate processing method, wherein the rotation axis R and the central axis C form an angle of 0 to 60°. In the substrate processing method according to any one of claims 10 to 16,
A substrate processing method, wherein the gas supplied to the cylindrical container is hydrogen. In the substrate processing method according to claim 17,
The substrate processing method, wherein the tubular reactive gas is a reactive gas mainly composed of hydrogen radicals when the substrate is irradiated with the reactive gas. In the substrate processing method according to claim 18,
A substrate processing method, wherein the substrate has an insulating film formed on the uppermost layer by plasma CVD, and the surface of the insulating film is modified by irradiation with the hydrogen radicals.

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