JP2006019489A - Plasma processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus for easily unifying a plasma density distribution near a substrate under plasma processing conditions, such as a wide range of gas species and pressure. <P>SOLUTION: The plasma processing apparatus, having a plasma processing chamber and a slot for introducing microwaves to the plasma processing chamber, easily changes the density and distribution of plasma near the substrate, by changing at least one of the shape and position of the slot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus such as an etching apparatus, an ashing apparatus, a CVD apparatus, a nitriding apparatus, and an oxidizing apparatus used in a semiconductor manufacturing process such as a semiconductor substrate and a liquid crystal substrate. In particular, the present invention relates to a plasma processing apparatus having a mechanism for adjusting the plasma distribution near the substrate to a desired density distribution.

  In order to process a semiconductor substrate with high quality using a plasma processing apparatus, it is important to make the plasma density distribution near the semiconductor substrate uniform. For example, if the plasma density distribution is non-uniform in the etching processing apparatus, problems such as non-uniform etching shape occur. Further, in the nitriding apparatus, the nitriding concentration is partially different, which causes variations in chip performance. Further, in the CVD processing apparatus, the partially deposited film thickness may be non-uniform, which may cause a reduction in production yield. This leads to deterioration in performance and quality of the semiconductor device.

  In the prior art plasma processing apparatuses disclosed in Japanese Patent Laid-Open Nos. 10-233295 and 5-345882, the slot arrangement provided in the slotted annular waveguide and the positional relationship between the semiconductor substrate and the plasma generator are as follows. By optimizing, the in-plane plasma processing uniformity of the semiconductor substrate was obtained. FIG. 2 details an example of a prior art plasma processing apparatus. 1 is a plasma processing chamber, 2 is a substrate, 3 is a substrate mounting table for holding the substrate 2, 5 is a processing gas introduction means, 6 is an exhaust port, and 8 is a slot for introducing microwaves into the plasma processing chamber 1. An endless annular waveguide, 11 is a slot provided in the endless annular waveguide 8 for every 1/2 or 1/4 of the wavelength in the microwave tube, and 7 is a dielectric for introducing microwaves into the plasma processing chamber 1. A body window 10 is a cooling water channel built in the endless annular waveguide 8.

  Microwaves are introduced into the plasma processing chamber 1 from the slots 11 arranged radially through the annular waveguide 8. The microwave excites the processing gas and generates plasma in the vicinity of the dielectric window 7. When the plasma generated in the vicinity of the dielectric window 7 exceeds a certain density, the microwave cannot enter the plasma processing chamber 1, is confined in the vicinity of the dielectric window 7, and interferes between the slots 11. . Due to the microwaves interfering between the radially arranged slots 11, the plasma generation portion density distribution becomes an annular shape. Plasma generated in the vicinity of the dielectric window 7 reaches the substrate 2 by diffusion.

  In order to make the plasma density distribution in the vicinity of the substrate 2 uniform, in addition to the distance between the substrate 2 and the plasma generating portion in the vicinity of the dielectric window 7 and the inner diameter of the plasma processing chamber 1, the arrangement of the slots has been adjusted. This slot arrangement adjustment is performed by removing / incorporating the metal plate with the slot perforated.

However, there is a problem that adjustment is inconvenient when the conditions change greatly and the plasma density in the vicinity of the substrate 2 becomes non-uniform.
JP-A-10-233295 JP-A-5-345882

  The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a plasma processing apparatus capable of easily uniforming the plasma density distribution in the vicinity of the substrate under a wide range of plasma processing conditions such as gas types and pressures. And

  The present invention relates to a plasma processing apparatus having a plasma processing chamber and a slot for introducing a microphone mouth wave into the plasma processing chamber, wherein the plasma near the substrate is changed by changing at least one of the shape and position of the slot. It is an object of the present invention to provide a plasma processing apparatus that can easily change the density and distribution.

  Since the ease of plasma diffusion varies depending on various conditions such as pressure, electron temperature, and gas type, the density distribution of plasma that reaches the vicinity of the substrate due to diffusion varies depending on these conditions. In addition, since the plasma diffuses from a high density to a low density, the plasma density distribution in the vicinity of the substrate changes depending on the position of the plasma generating portion having the highest plasma density. Further, since the plasma generation unit is in the vicinity of the slot, it moves by moving the slot. The present invention moves the plasma generating part in the vicinity of the slot by changing at least one of the shape and position of the slot even if the ease of plasma diffusion changes depending on the plasma conditions such as gas type and pressure. Provided is a plasma processing apparatus for easily uniforming a plasma density distribution in the vicinity of a substrate regardless of plasma conditions.

  Further, the shape and position of the slot may be changed by moving a part of the slotted endless annular waveguide, or the relative movement of at least two electrically grounded conductors. Or may be changed by replacing a part of the microwave waveguide provided with the slot by means for replacing a part of the microwave waveguide provided with the slot.

  In addition, by making the shape such as the length or width of only the slot close to the microwave introduction part of the endless annular waveguide smaller than the other slots, the microwaves are uniformly emitted from each slot, whereby the substrate The nearby plasma density distribution may be made uniform. Since the standing wave intensity in the microwave tube in the vicinity of the microwave introduction portion is strong, the amount of microwave emission from each slot can be made uniform by making the slot cross-sectional shape near here smaller than other slots.

  Further, the present invention provides means for alternately performing at least one time a step of changing at least one of the shape and position of the slot on the same substrate and a step of introducing a microwave into the plasma processing chamber. By providing the plasma processing apparatus, it is possible to easily change the plasma processing amount distribution in the substrate surface.

  When the pressure in the plasma processing chamber is high and the plasma is not sufficiently diffused, the plasma processing amount distribution in the substrate surface is larger and non-uniform in the place near the plasma generating portion having the highest plasma density. In such a case, the present invention repeats the step of changing the position of the slot and the step of plasma processing the substrate, for example, by repeating the slot position while moving the position of the slot from the vicinity of the center of the substrate toward the periphery of the substrate. Provided is a plasma processing apparatus that makes a plasma processing amount distribution uniform.

  The plasma processing apparatus of the present invention includes means for changing at least one of the shape and position of the slot for introducing the microphone mouth wave into the plasma processing chamber, thereby changing the density and position of the plasma source generated in the vicinity of the slot. Further, it is possible to provide a plasma processing apparatus that can easily uniformize the density and distribution of plasma that is transported by gas flow or diffusion and reaches the vicinity of the substrate even under plasma processing conditions such as a wide range of gas types and pressures.

  Further, by providing means for alternately performing at least one time the step of changing at least one of the shape and position of the slot and the step of introducing the microwave into the plasma processing chamber with respect to the same substrate. A plasma processing apparatus that easily superimposes the plasma processing amount distribution in the substrate surface even under a wide range of plasma processing conditions such as gas types and pressures, by superimposing several plasma processing amount distributions determined by the shape and position of the substrate. Can provide.

Example 1
A first embodiment of the plasma processing apparatus of the present invention will be described in detail with reference to FIG. 1 is a plasma processing chamber, 2 is a substrate, 3 is a substrate mounting table for holding the substrate 2, 5 is a processing gas introduction means, 6 is an exhaust port, and 7 is a dielectric window for introducing microwaves into the plasma processing chamber 1. 10 is a cooling water channel built in the endless annular waveguide 8, 8 is an endless annular waveguide, 20 is fixed to the endless annular waveguide 8, and is 1/2 or 1 / of the wavelength in the microwave tube. A plate provided with an opening having a width of 4 mm and a length of 90 mm every four, but the width of the slot closest to the opening for introducing the microwave into the endless annular waveguide is approximately 3.6 mm, 21 is a band-like shape having a width of 40 mm A plate having an opening, 22 is a driving means for detecting the rotation angle of the plate 21 while rotating the plate 21, and 23 is a contact means for electrically contacting the endless annular waveguide 8 and the plate 21 with a metal spring. A parallelogram slot 24 having a width of 4 mm and a length of 48 mm as shown in FIG. 3 is used to emit microwaves to the plasma processing chamber 1 at a location where the openings of the plate 20 and the plate 21 of the endless annular waveguide 8 overlap. Appears. However, the width of the slot closest to the portion where the microwave is introduced into the endless annular waveguide 8 is approximately 3.6 mm. The plate 21 rotated by the driving means 22 moves outward from the center without changing the slot length.

  In the plasma processing apparatus of the present invention, these devices are operated in a predetermined order by a controller (not shown) such as a sequencer or a computer to perform plasma processing on the substrate.

  The substrate 2 is nitrided using the plasma processing apparatus of the present invention. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred to the substrate mounting table 3 by means (not shown). Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to hold the plasma processing chamber 1 at 130 Pa. Subsequently, the plate 21 is rotated by the driving means 22 so that the center of the slot 24 is opened approximately in the middle between the center and the outer periphery of the dielectric window 7. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 8 and the dielectric window 7. The microwave does not leak from other than the slot 24 because the endless annular waveguide 8, the plate 20, and the plate 21 are in electrical contact. Further, since the microwave becomes a standing wave between the slots 24, the plasma is excited between the slots 24. Since the center of the slot 24 is approximately in the middle between the center and the outer periphery of the dielectric window 7, the plasma is excited in a ring shape in the middle between the center and the outer periphery of the dielectric window 7. The nitrogen ions in the plasma reach the vicinity of the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and enter the substrate 2 to nitride the silicon oxide film. After 3 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is transferred out of the plasma processing chamber 1.

  After the nitriding treatment, the silicon oxide equivalent thickness of the silicon oxynitride film on the surface of the substrate 2 was measured with an ellipsometer manufactured by KLA Tencor, and the distribution was almost uniform.

  Subsequently, the substrate 2 is nitrided by changing the pressure to 5 Pa. At this time, the plate 21 is rotated by the driving means 22 so that the slot 24 opens to the outermost side. Then, the substrate 2 is nitrided in the same manner as described above.

  After the nitriding treatment, the silicon oxide equivalent thickness of the silicon oxynitride film on the surface of the substrate 2 was measured with an ellipsometer manufactured by KLA Tencor, and the distribution was almost uniform.

  Since the plasma has the slots 24 on the outermost side, the plasma is excited in an annular shape on the outer side. However, since the pressure is low, the plasma is easily diffused and has a substantially uniform density distribution in the vicinity of the substrate.

  Even if the ease of plasma diffusion changes depending on the plasma conditions such as pressure as in this embodiment, the two metal plates are moved relative to each other to move the slot and move the plasma generating portion near the slot. The plasma density distribution near the substrate can be easily made uniform regardless of pressure.

(Example 2)
A second embodiment of the plasma processing apparatus of the present invention will be described in detail using the plasma processing apparatus of the first embodiment. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred to the substrate mounting table 3 by means (not shown). Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to maintain the plasma processing chamber 1 at 260 Pa. Subsequently, the plate 21 is rotated by the driving means 22 so that the slot 24 opens toward the center. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 8 and the dielectric window 7. Since there is a slot 24 closer to the center, the plasma is excited in a ring shape toward the center. Then, more nitrogen ions in the plasma reach the center of the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and are incident on the substrate 2, thereby nitriding more silicon oxide film at the center of the substrate 2. . After 3 minutes, stop the microwave power supply.

  Subsequently, the plate 21 is rotated by the driving means 22 so that the slot 24 opens to the outermost side. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 8 and the dielectric window 7. Since there is a slot 24 on the outermost side, the plasma is excited in an annular shape on the outer side. Then, more nitrogen ions in the plasma reach the outer periphery of the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and are incident on the substrate 2, and more nitride the silicon oxide film on the outer periphery of the substrate 2. . After 6 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is transferred out of the plasma processing chamber 1.

  After the nitriding treatment, the silicon oxide equivalent thickness of the silicon oxynitride film on the surface of the substrate 2 was measured with an ellipsometer manufactured by KLA Tencor, and the distribution was almost uniform.

  In order to make the plasma processing amounts at the center and the periphery in the substrate surface coincide with each other, it is preferable that the processing is performed for a longer time on the periphery of the substrate. This is because the area per center angle is larger as the outer circumference of the substrate is increased, and more plasma is recombined and disappeared by walls or the like, so that the plasma density in the vicinity of the substrate tends to decrease.

  In the case where the pressure is high and the plasma is not sufficiently diffused as in this embodiment, the plasma processing amount distribution in the substrate surface is larger and non-uniform in the place near the plasma generating portion having the highest plasma density. In such a case, the step of changing the position of the slot and the step of introducing the microwave into the plasma processing chamber are alternately repeated while moving the position of the slot from the vicinity of the center of the substrate toward the periphery of the substrate. The throughput distribution can be made uniform.

  In the present embodiment, a plate as shown in FIG. 3 is used. However, the arrangement and shape of the slots 24 may be determined by a combination of plates as shown in FIGS. In the present embodiment, the arrangement of the slots 24 is changed once during the plasma processing, but may be changed a plurality of times, for example, in the center, in the middle, and outward.

Example 3
A third embodiment of the plasma processing apparatus of the present invention will be described in detail with reference to FIG. Reference numeral 20 denotes a plate which is fixed to the endless annular waveguide 8 and has an opening having a width of 4 mm and a length of 90 mm every 1/2 or 1/4 of the wavelength in the microwave tube. However, microwaves are introduced into the endless annular waveguide. The width of the slot closest to the opening to be made is 3.6 mm, 21 is a windmill plate, 26 is a plate having a fan-shaped opening, and 22 is a rotation angle detected while rotating the plate 21 through a hollow tube 27. 25, a driving means for detecting the rotation angle of the plate 26 while rotating the plate 26 via the shaft 28, and 23, a contact for electrically connecting the plate 21, the plate 26 and the endless annular waveguide 8 with a metal spring. Means 29 is a contact means for electrically connecting the end of the plate 26 and the plate 20 with a metal spring. Microwaves are emitted into the plasma processing chamber 1 at positions where the openings of the plate 20, plate 21 and plate 26 of the endless annular waveguide 8 overlap each other, as shown in FIG. A ~ 24 mm parallelogram slot 24 appears. The slot 24 changes the position of the end near the center by the plate 21 rotated by the driving means 22 and changes the position of the peripheral end by the plate 26 rotated by the driving means 25 to change the arrangement and length of the slots.

  The substrate 2 is nitrided using the plasma processing apparatus of the present invention. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred to the substrate mounting table 3 by means (not shown). Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to maintain the plasma processing chamber 1 at 260 Pa. Subsequently, the plate 21 and the plate 26 are rotated by the driving means 22 and the driving means 25 so that the slot 24 is opened with the slot length of 40 mm closest to the center. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 8 and the dielectric window 7. The microwave does not leak from other than the slot 24 because the endless annular waveguide 8, the plate 20, and the plate 21 are in electrical contact. Further, since the microwave becomes a standing wave between the slots 24, the plasma is excited between the slots 24. Since the slot 24 is located closest to the center, the plasma is excited in a ring shape toward the center. Then, more nitrogen ions in the plasma reach the center near the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and enter the substrate 2, and more silicon oxide films near the center of the substrate Nitrid. After 3 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is transferred out of the plasma processing chamber 1.

  As described above, the present embodiment moves the microwave plasma generator near the slot with the highest plasma density by moving the three metal plates relative to each other and changing the length and position of the slot, and near the substrate. The plasma density distribution can be easily changed.

Example 4
A fourth embodiment of the plasma processing apparatus of the present invention will be described in detail with reference to FIG. 1 is a plasma processing chamber, 2 is a substrate, 3 is a substrate mounting table for holding the substrate 2, 5 is a processing gas introduction means, 6 is an exhaust port, and 31 is a slot for introducing microwaves into the plasma processing chamber 1. An endless annular waveguide 33 is a dielectric wall for introducing a microwave into the plasma processing chamber 1, 32 is a slot provided every 1/2 or ¼ of the wavelength in the microwave tube, and 30 is an endless annular guide Drive means for moving the wave tube up and down. The dielectric wall 33 is longer than the moving range of the endless annular waveguide 31 that is moved up and down by the driving means 30.

  The substrate 2 is nitrided using the plasma processing apparatus of the present invention. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred and placed on the surface by means not shown. Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to hold the plasma processing chamber 1 at 130 Pa. Subsequently, the endless annular waveguide 31 is moved by the driving means 30 so that the slot 32 is at the height farthest from the substrate 2. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 31 and the dielectric window 33. Since the microwave becomes a standing wave between the slots 32, the plasma is excited between the slots 32. Since there is a slot 32 at the most distant height, the plasma is excited in a band along the surface of the dielectric window 33 at the most distant height from the substrate 2. The nitrogen ions in the plasma reach more in the vicinity of the center of the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and enter the substrate 2, and more nitride the silicon oxide film in the center of the substrate. After 2 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is transferred out of the plasma processing chamber 1.

  Subsequently, the endless annular waveguide 31 is moved by the driving means 30 so that the slot 32 is almost the same height as the substrate 2, and the substrate 2 is newly nitrided. Since the slots 32 are approximately at the same height as the substrate 2, the plasma is excited in a band shape along the surface of the dielectric window 33 at approximately the same height as the substrate 2. Then, more nitrogen ions in the plasma reach the vicinity of the outer periphery of the substrate 2 while diffusing, are accelerated by the ion sheath generated on the surface of the substrate 2 and are incident on the substrate 2, and more nitride the silicon oxide film near the outer periphery of the substrate. .

  By moving the slotted endless annular waveguide up and down, the plasma generating section formed near the slot is moved up and down, and the distance between the plasma generating section and the substrate is changed. The longer the diffusion path, the more diffused the plasma. That is, the longer the diffusion path, the higher the density of the plasma distribution near the center of the substrate, and the shorter the density, the higher the density near the outer periphery of the substrate.

  As described above, the present embodiment moves the microwave plasma generating portion near the slot with the highest plasma density by moving the annular waveguide provided with the slot up and down and changing the slot position. The density distribution can be easily changed.

(Example 5)
A fifth embodiment of the plasma processing apparatus of the present invention will be described in detail with reference to FIG. Reference numeral 34 denotes a plate fixed to the endless annular waveguide 31 and provided with an opening having a width of 4 mm and a length of 90 mm for every ½ or ¼ of the wavelength in the microwave tube. However, the microwave is introduced into the endless annular waveguide. The width of the slot closest to the opening is 3.6 mm, 35 is a plate with a wedge-shaped opening, 36 is a driving means for rotating the plate 35, and 37 is a contact means for electrically connecting the plates 34 and 35. is there. A microwave is emitted to the plasma processing chamber 1 at a place where the openings of the plate 34 and the plate 35 of the endless annular waveguide 31 overlap each other, as shown in FIG. 10 and having a width of 4 mm and a length of 3.6 mm and a length of 40 to 60 mm. A trapezoidal slot 38 appears. The opening length of the slot 38 is changed by the plate 35 rotated by the driving means 36.

  The substrate 2 is nitrided using the plasma processing apparatus of the present invention. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred to the substrate mounting table 3 by means (not shown). Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to hold the plasma processing chamber 1 at 130 Pa. Subsequently, the plate 35 is rotated by the driving means 36 so that the slot 38 is opened with a slot length of 40 mm. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguide 31 and the dielectric window 33. The microwave does not leak from other than the slot 38 because the endless annular waveguide 31 and the plate 35 are in electrical contact. Further, since the microwave becomes a standing wave between the slots 38, the plasma is excited between the slots 38. Nitrogen ions in the plasma reach the vicinity of the substrate 2 while diffusing, are accelerated by an ion sheath generated on the surface of the substrate 2 and are incident on the substrate 2 to nitride the silicon oxide film. After 3 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is transferred out of the plasma processing chamber 1.

  If the slot length is about 40 mm, which is substantially the same as 1/4 of the wavelength in the microwave tube, the microwave emitted from the slot becomes very small. If the slot length is about 80 mm, which is substantially the same as half the wavelength in the microwave tube, almost all microwaves are emitted from the slot. By adjusting the slot length, more preferably between 40 and 50 mm, the microwave emission amount can be increased while maintaining the emission amount balance from each slot. Since the plasma generation unit density increases / decreases according to the amount of microwave emission, the plasma generation unit density can be increased / decreased by changing the slot length.

  As described above, in this embodiment, the plasma generation unit density can be changed by changing the slot length and changing the microwave power introduced into the plasma processing chamber, so that the plasma density near the substrate can be changed easily.

(Example 6)
FIG. 11 shows a seventh embodiment of the plasma processing apparatus of the present invention. The plasma processing apparatus of this embodiment is a combination of FIG. 6 and FIG.

  The substrate 2 is nitrided using the plasma processing apparatus of the present invention. A silicon substrate 2 with an oxide film having a thickness of 2 nm is transferred and placed on the surface by means not shown. Next, the plasma processing chamber 1 is exhausted to 0.1 Pa or less through an exhaust system (not shown). Subsequently, 500 sccm of nitrogen is introduced into the plasma processing chamber 1 from the processing gas introduction means 5. Next, a conductance valve (not shown) provided in the exhaust system is adjusted to hold the plasma processing chamber 1 at 130 Pa. Subsequently, the plate 35 is rotated by the driving means 36 so that the slot length of the slot 38 on the side surface of the plasma processing chamber 1 is 45 mm. Further, the plates 21 and 26 are rotated by the driving means 22 and 25 so that the slot 24 on the upper surface of the plasma processing chamber 1 is closest to the center and has a slot length of 42 mm. Subsequently, a microwave of 1.5 kW is supplied from the microwave power source to the plasma processing chamber 1 through the slotted endless annular waveguides 8 and 31 and the dielectric windows 7 and 33. Since the microwaves are standing waves between the slots 24 and 38, plasma is excited between the slots 24 and 38. Nitrogen ions in the plasma reach the vicinity of the substrate 2 while diffusing, reach the surface of the substrate 2, and nitride the silicon oxide film. The plasma excited on the upper surface of the plasma processing chamber 1 is mainly nitrided in the center of the substrate 2, and the plasma excited on the side surface of the plasma processing chamber 1 is mainly nitrided on the outer periphery of the substrate 2. By adjusting these nitriding amounts according to the lengths and positions of the slots 24 and 38, the nitriding amount in the surface of the substrate 2 is made uniform. After 3 minutes, the microwave power supply is stopped, the supply of nitrogen gas is stopped, the plasma processing chamber 1 is evacuated to 0.1 Pa or less, and then the substrate 2 is carried out of the plasma processing chamber 1.

  As described above, the present embodiment has an annular waveguide with slots on the side surface and upper surface of the plasma processing chamber, respectively, and the plasma excited on the side surface and upper surface of the plasma processing chamber by changing the position and length of each slot. Thus, the plasma density distribution in the vicinity of the substrate can be made uniform.

(Example 7)
A seventh embodiment of the plasma processing apparatus of the present invention will be described in detail with reference to FIG. 1 is a plasma processing chamber, 41 is an endless annular waveguide, 42 is a driving means for moving the endless annular waveguide 41 in the vertical direction, 44 is a replaceable slot plate having a slot, and 43 is an endless annular guide Contact means for electrically contacting the wave tube 41 and the slot plate 44 with a metal spring, 45 is a storage place for storing the replacement slot plate, 46 is a storage place 45 for the slot plate 44 installed in the endless annular waveguide 41. An exchanging means for exchanging with the slot plate 44 housed in the slot plate, 47 is a positioning means for providing a conical metal pin at a predetermined location on the slot plate 44 and further providing a mortar-shaped hole at a predetermined location on the endless annular waveguide 41 for fitting. It is.

  The slot plate 44 of the plasma processing apparatus of the present invention is replaced as follows. The endless annular waveguide 41 is raised by the driving means 42. Subsequently, the slot plate 44 is transported to a predetermined location in the storage 45 by the exchanging means 46. Subsequently, the desired slot plate 44 is transferred from the storage 45 to the plasma processing chamber 1. Then, the endless annular waveguide 41 is lowered by the driving means 42. The endless annular waveguide 41, the slot plate 44, and the plasma processing chamber 1 are in electrical contact with each other by the contact means 43 and do not leak microwaves.

As described above, in this embodiment, the shape and position of the slot for introducing the microwave into the plasma processing chamber can be easily changed by exchanging the slot plate.
The present invention is not limited to nitridation of a semiconductor substrate. For example, the present invention is also applicable to a plasma processing apparatus such as an etching apparatus, an ashing apparatus, a CVD apparatus, a nitriding apparatus, and an oxidizing apparatus used in a semiconductor manufacturing process such as a semiconductor substrate and a liquid crystal substrate It is valid.

The figure explaining the 1st Example of this invention. The figure explaining a prior art. The figure explaining the slot details of 1st Example of this invention. The figure explaining the slot details of 1st Example of this invention. The figure explaining the slot details of 1st Example of this invention. The figure explaining the 3rd Example of this invention. The figure explaining the slot details of the 3rd example of the present invention. The figure explaining the 4th Example of this invention. The figure explaining the 5th Example of this invention. The figure explaining the slot details of the 5th example of the present invention. The figure explaining the 6th Example of this invention. The figure explaining the 7th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma processing chamber 2 Substrate 3 Substrate mounting table 5 Gas introduction means 6 Exhaust port 7 Dielectric window 8 Endless annular waveguide 10 Cooling channel 11 Slot 20 Plate 21 Plate 22 Drive means 23 Contact means 24 Slot 25 Drive means 26 Plate 27 hollow tube 28 shaft 29 contact means 30 drive means 31 endless annular waveguide 32 slot 33 dielectric wall 34 plate 35 plate 36 drive means 37 contact means 38 slot 41 endless annular waveguide 42 drive means 43 contact means 44 Slot plate 45 Storage 46 Replacement means 47 Positioning means

Claims (6)

  A plasma processing apparatus comprising a plasma processing chamber, a substrate, a substrate mounting table, and a waveguide provided with a plurality of slots for introducing a microphone mouth wave into the plasma processing chamber, wherein at least one of the shape and position of the slot is A plasma processing apparatus comprising means for changing.   A means for alternately performing at least one time the step of changing at least one of the shape and position of the slot and the step of introducing a microwave into the plasma processing chamber is provided for the same substrate. The plasma processing apparatus according to claim 1.   3. The plasma processing apparatus according to claim 1, wherein the position of the slot is changed by moving a part of the waveguide having the slot.   4. The plasma processing apparatus according to claim 1, wherein at least one of the shape and position of the slot is changed by relatively moving at least two electrically grounded conductors.   Means for exchanging a part of the microwave waveguide provided with the slot, and changing at least one of the shape and position of the slot by exchanging a part of the microwave waveguide provided with the slot; The plasma processing apparatus according to claim 1, wherein:   The microwave waveguide provided with the slot is a slotted endless annular waveguide, and only the shape of the slot near the microwave introduction portion of the slotted endless annular waveguide is different from other slot shapes. 6. The plasma processing apparatus according to claim 1, wherein

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