JP6985758B2 - Plasma processing equipment - Google Patents

Description

The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus for creating a shape of a surface of an object to be processed with high precision.

Conventionally, a plasma CVM (Chemical Vaporization Machining) method has been provided as a method of etching the surface of an optical substrate material or an electronic device material using a local plasma to create a highly accurate shape (Patent Documents 1 and 1). 2). In the plasma CVM method, the surface of an object to be processed is processed into an arbitrary shape with an accuracy of nanometer order by numerically controlling and scanning plasma generated locally under atmospheric pressure.

In Patent Document 1, a neutral radical based on a reaction gas generated by an electrode to which a high voltage is applied is supplied to the machined surface of the object to be machined, and the neutral radical reacts with an atom or molecule on the machined surface by a radical reaction. It is possible to vaporize and remove the generated volatile substances and process them with high precision without introducing defects or thermally altered layers into semiconductors such as silicon single crystals or conductors or insulators such as glass and ceramics. A strain precision machining method is disclosed. This patent document 1 is a principle patent of the plasma CVM method.

In Patent Document 2, using the processing principle of Patent Document 1, the correlation data between the processing time and the processing amount, which is determined according to the type of the reaction gas and the material of the object to be processed, and the pre-processed surface are described. Distortion-free precision numerical control machining method by a radical reaction in which the machining time is numerically controlled according to the coordinate difference based on the coordinate data of the target machined surface is disclosed. Specifically, the local machining amount is determined from the difference between the shape of the machined object before machining and the shape of the target machined surface, and based on this, the electrode and the surface of the machined object are numerically controlled and relatively scanned. Then, the scanning speed and the residence time are controlled to process the desired shape.

Further, Patent Document 3 discloses a material removal tool capable of confining RF-excited plasma in a limited region, scanning it on the surface of an object to be processed, and removing the material in a non-contact manner by a plasma-assisted chemical etching reaction. There is. Specifically, the material removal tool comprises a means for limiting the plasma chamber cavity and a means for supplying the reaction gas to the plasma chamber cavity and supplying RF power to the reaction gas in the plasma chamber cavity. A means for generating an etching reaction, a means for surrounding the outer peripheral edge of the plasma chamber cavity to suppress plasma generation outside the plasma chamber cavity, and a means for local plasma etching reaction on different localized regions of the workpiece. It is provided with a means for adjusting the position of the plasma chamber cavity with respect to the object to be processed so as to adjust the position. The processing method described in Patent Document 3 is called PACE (Plasma Assisted Chemical Etching).

In Cited Document 4, the injection port having a constant diameter in the plasma generating portion is opposed to a predetermined convex portion of the object to be processed, and the active seed gas is jetted from the injection port to the convex portion to be etched. A plasma etching method for flattening a portion is disclosed. The plasma generating part is located outside the chamber in which the object to be processed is placed, and the _{active seed gas containing SF 6} in the conduit is irradiated with microwaves from the microwave oscillator to generate plasma, and the plasma containing F gas is generated. Is sprayed onto the object to be machined from the outlet of the conduit. The processing method described in Patent Document 4 is called DCP (Dry Chemical Planarization).

In Patent Document 5, when a glass substrate for a photomask is flattened by using the plasma CVM method, a dummy glass substrate is installed at the outer peripheral edge of the glass substrate, and plasma becomes unstable at the outer peripheral portion of the glass substrate. The technology to prevent this is disclosed. However, it is not enough to use this dummy glass substrate alone, and if an arc is generated in the gap between the glass substrate of the object to be processed and the dummy glass substrate, the plasma becomes unstable, the processing accuracy is lowered, and the substrate is damaged. Will be given.

Japanese Unexamined Patent Publication No. 1-125829 Japanese Unexamined Patent Publication No. 4-246184 Japanese Unexamined Patent Publication No. 5-347277 Japanese Unexamined Patent Publication No. 10-147893 Japanese Unexamined Patent Publication No. 2006-027936

In the conventional plasma processing device, the object to be processed and the electrode are arranged in the chamber, the process gas is supplied into the chamber, and plasma is generated between the object to be processed and the electrode. Therefore, the electrode is also converted to plasma. It will be constantly exposed and the electrodes will be severely worn. Further, in Patent Documents 3 and 4, since the plasma nozzle and the XY stage are arranged in the chamber and the object to be processed is scanned relative to the plasma nozzle, the chamber becomes large and complicated, and the process The amount of gas used was also high.

Further, although Patent Document 3 does not clearly describe the pressure in the chamber, the Debye length of the plasma is described as about 2 mm, which is about the same as the Debye length of the plasma used in a normal device process. From this, it can be inferred that the pressure is 1 Torr or less. In the low pressure plasma of 1 Torr or less used in the conventional device process, the etching rate (processing rate) is slow because the density of active species such as F radicals is low. On the other hand, when atmospheric pressure plasma is used, the radical density becomes very high, but the mean free path is inversely proportional to the pressure, so at atmospheric pressure the mean free path of electrons becomes very short, about 1 μm, and plasma is generated. The volume of the region is reduced, which does not increase the total number of radicals as expected and does not significantly improve the processing speed compared to low pressure plasma.

Requirements for the practical application of numerically controlled plasma processing method using local plasma are increase of processing speed, suppression of damage to the workpiece due to arc discharge, improvement of machining stability at the edge of the workpiece, and generation of plasma. The running cost can be reduced by suppressing the wear of the electrodes and reducing the amount of process gas used. However, in the conventional atmospheric pressure plasma CVM method, the above-mentioned problems remain unsolved. Therefore, the present invention is to provide a plasma processing apparatus capable of solving the above-mentioned problems at once.

The present invention constitutes the following plasma processing apparatus in order to solve the above-mentioned problems.

(1)
It is a non-sealed plasma processing device that is placed under the open air and forms a plasma generation space with the surface of a plate-shaped object to be processed.
It is partitioned by a partition wall from the side surface to the lower surface and the upper surface, and a part or all of the upper surface is formed of a dielectric plate made of plasmamics to form openings on both sides through which the object to be processed can pass. A non-sealed chamber with a plasma generation chamber that serves as a plasma generation space and exhaust chambers on both sides of the chamber.
An electrode placed in a non-contact state on the dielectric plate under the open atmosphere,
A gas supply system that supplies a process gas containing a reaction gas to the plasma generation space,
A gas exhaust system having a differential exhaust structure that exhausts the process gas and the atmosphere from both exhaust chambers to maintain the pressure in the plasma generation space in a reduced pressure state of 20 to 200 Torr.
A high-frequency power supply that applies a high-frequency electric field to the electrodes,
The surface of the object to be processed is treated with the plasma generated in the plasma generation space while the object to be processed passes from one opening to the other opening.
A plasma processing device characterized by this.

( 2 )
The plasma processing apparatus according to (1 ), wherein the opening of the chamber is provided with a sealing material that elastically closes a gap with the object to be processed.

( 3 )
The plasma processing apparatus according to (1 ) or ( 2 ), wherein the electrodes can be numerically controlled and scanned by a drive mechanism at least in a direction orthogonal to the feed direction of the object to be machined.

( 4 )
It is a non-sealed plasma processing device that is placed under the open air and forms a plasma generation space with the surface of a plate-shaped object to be processed.
A plasma-coated electrode is placed in the center, a gas ejection tube for process gas containing reaction gas concentrically is formed around it, and multiple gas suction tubes are formed on the outside, and the lower surface is formed substantially flat. Is located slightly retracted from the gas ejection pipe, and has an electrode pad having a structure that forms a predetermined gap that serves as the plasma generation space between the tip thereof and the object to be processed.
A gas supply system including a gas supply pipe connected to the gas ejection pipe and supplying process gas from the gas supply pipe to the plasma generation space through the gas ejection pipe.
Differences including a gas exhaust pipe connected to the gas suction pipe , in which the process gas and the atmosphere are exhausted through the gas suction pipe, and the pressure in the plasma generation space is maintained in a reduced pressure state of 20 to 200 Torr. A gas exhaust system with a dynamic exhaust structure and
A high-frequency power supply that applies a high-frequency electric field to the electrodes,
The electrode pad is numerically controlled and scanned along the surface of the object to be machined, and the surface of the object to be machined is treated with the plasma generated in the plasma generation space.
A plasma processing device characterized by this.

( 5 )
The plasma according to any one of (1) to (4 ), wherein the process gas is a mixed gas of a rare gas and a halogen element-containing gas or an oxygen gas, and the creation of the surface shape of the object to be processed is a removal process. Processing device.

The plasma processing apparatus of the present invention as described above can solve all the problems in the conventional atmospheric pressure plasma CVM method. Large plate-shaped objects to be machined can be machined by locally differential exhaust. In addition, the reduced pressure plasma increases the processing speed and can realize a significant reduction in processing time. In addition, damage to the workpiece can be avoided by suppressing the generation of arc discharge. In addition, the amount of process gas used can be reduced, and running costs and manufacturing costs can be significantly reduced.

It is a conceptual diagram of the numerical control plasma processing apparatus which concerns on the related invention of this invention. It is a graph which shows the profile of the unit processing mark for each processing gap. It is a graph of the machining speed for each machining gap. It is a graph which compared the processing speed of the conventional atmospheric pressure plasma CVM and the decompression plasma CVM of this invention. It is a simplified sectional view which shows the arrangement for testing the processing stability at the end part of the processing object by the conventional atmospheric pressure plasma CVM. It is a simplified sectional view which shows the arrangement for testing the processing stability at the end part of the processing object by the reduced pressure plasma CVM of this invention. It is explanatory plan view which shows the scanning range of a local plasma generation area. It is a graph which shows the processing amount at the edge part and the center part when the quartz glass substrate is processed by the conventional atmospheric pressure plasma CVM. It is a graph which shows the processing amount in the edge part and the center part when the quartz glass substrate is processed by the reduced pressure plasma CVM of this invention. It is a conceptual perspective view of the plasma processing apparatus of 1st Embodiment of this invention. It is also a simplified plan view. It is a conceptual perspective view of the plasma processing apparatus of the 2nd Embodiment of this invention. It is also a partial cross-sectional view.

Next, the present invention will be described in more detail based on the embodiments shown in the accompanying drawings. FIG. 1 shows a conceptual diagram of a numerically controlled plasma processing apparatus according to a related invention of the present invention, in which reference numeral 1 is an electrode, 2 is a high frequency power supply, 3 is a chamber, 4 is an exhaust system, 5 is a gas supply system, and 6 is. The scanning means, 7 is a sample table, 8 is a partition wall, and 9 is a dielectric plate. Further, S1 indicates a first space, S2 indicates a second space, P1 indicates a first set pressure, P2 indicates a second set pressure, G indicates a gap, W indicates an object to be processed, and LP indicates a local plasma generation region.

As shown in FIG. 1, the numerically controlled plasma processing apparatus according to the related invention of the present invention has an electrode 1 arranged in the first space S1 of the first set pressure P1 to generate a local plasma, and the electrode 1 A high-frequency power supply 2 that applies a high-frequency electric field to the chamber 3, an airtight chamber 3 in which the workpiece W is arranged in the internal second space S2, and a second set pressure of the second space S2 by drawing a vacuum inside the chamber 3. An exhaust system 4 having a pressure adjusting function for setting P2 to a reduced pressure atmosphere lower than the first set pressure P1, a gas supply system 5 for supplying process gas into the chamber 3, and the object W to be processed are the electrodes. It is composed of a scanning means 6 for scanning with respect to 1.

More specifically, in the chamber 3, at least the electrode 1 and the object to be processed are among the grounded conductive sample table 7 on which the object W to be processed is placed and the partition wall 8 forming the second space S2. A dielectric plate 9 provided at a portion located between W is provided, and a local plasma generation region based on a process gas is provided between the workpiece W and the dielectric plate 9 by a high-frequency electric field applied to the electrode 1. The gap G to be LP is set. In the present embodiment, it is assumed that the thin plate-shaped object W to be processed is flattened, but the present invention is not particularly limited.

As described above, in the present invention, the first space S1 and the second space S2 are separated by the partition wall 8, the first space S1 is the space of the first set pressure P1, and the electrode 1 is in the first space S1. The second space S2 is a space of the second set pressure P2 lower than the first set pressure P1, and the workpiece W is arranged in the second space S2 and the second set pressure P2 is applied. The process gas is supplied while maintaining the process gas, and numerically controlled scanning is performed relatively while maintaining the distance between the electrode 1 and the workpiece W, and the partition wall 8 located at least between the electrode 1 and the workpiece W is located. Is formed of a dielectric plate 9, and a high-frequency electric field is applied to the electrode 1 to generate plasma in a predetermined gap G set between the dielectric plate 9 and the object W to be processed to generate plasma in the process gas. It is characterized in that the surface shape of the object to be processed W is created based on the active species.

That is, it is characterized in that the electrode 1 and the local plasma generation region LP are located in different spaces and are shielded by the dielectric plate 9, whereby the electrode 1 is not directly exposed to plasma. Therefore, there is no wear due to plasma.

Here, the first set pressure P1 of the first space S1 is 700 to 800 Torr (93.1 to 106.4 kPa), and the second set pressure P2 of the second space S2 is 20 to 200 Torr (2.66 to 26). Set to .6 kPa). In particular, when the first set pressure P1 is atmospheric pressure, the first space S1 may be a space under the open atmosphere. However, in order to keep the atmosphere around the electrode 1 always constant, the first space S1 may be defined in a closed case, and the inside thereof may be filled with nitrogen gas or carbon dioxide gas instead of air. The pressure (first set pressure P1) may be set to a pressure near the atmospheric pressure (700 to 800 Torr). The second set pressure P2 is set to 20 to 200 Torr, which is sufficiently higher than 1 Torr or less used in the conventional semiconductor device manufacturing process.

The process gas is a mixed gas of a rare gas and a halogen element-containing gas or an oxygen gas, and the creation of the surface shape of the object to be processed is the removal process. Examples of the noble gas include helium gas and argon gas. Examples of the halogen element include fluorine and chlorine. Specifically, the halogen element-containing gas includes SF ₆ , CF ₄ , NF _3, etc. as those containing the fluorine element, and those containing the chlorine element. there are Cl _{2, CCl 4,} PCl 4, and the like. Further, another gas may be mixed with the process gas according to various purposes, and for example, O ₂ gas can be added for the purpose of improving the processing speed and reducing the deposits. In addition to the removal process, the present invention can also form a film whose thickness is locally changed in principle by selecting a process gas.

As the dielectric plate 9, a ceramic plate having corrosion resistance against active species of process gas and having mechanical strength capable of withstanding a pressure difference between inside and outside is used. Specifically, the dielectric plate 9 uses a material such as aluminum oxide (alumina) or aluminum nitride, which has high mechanical strength and high thermal conductivity even if the plate thickness is thin. Incidentally, the bending strength of alumina (99.9%) is 400 MPa, the relative permittivity is 9.9, the thermal conductivity is 34 W / m · K, and the bending strength of aluminum nitride (99.9%) is 220 MPa, the ratio. The permittivity is 8.5 and the thermal conductivity is 67 W / m · K. For comparison, the bending strength of quartz glass is 65 MPa, the relative permittivity is 3.9, and the thermal conductivity is 1.4 W / m · K.

The chamber 3 is configured by joining the partition wall 8 and a box body provided with the dielectric plate 9 on a part or all of the upper surface to the upper surface of the base plate 10 made of a conductor in an airtight state. There is. Then, inside the chamber 3, the sample table 7 is provided on the upper surface of the base plate 10 via the gap adjusting means 11. The gap G between the dielectric plate 9 and the object W to be machined is set by adjusting the height of the sample table 7 by the gap adjusting means 11. Specifically, the gap adjusting means 11 is composed of three or more screw members screwed onto the upper surface of the base plate 10, but may be composed of a Z table. The base plate 10 is grounded, and the sample table 7 is also at the ground potential via the gap adjusting means 11.

In the present embodiment, the scanning means 6 is provided with the chamber 3 placed on the upper surface, driven by the numerical control device 12, and moves the chamber 3 with respect to the electrode 1 while maintaining the gap G. It consists of an XY stage to be made to. In this case, the electrode 1 is fixed, but since it is sufficient that the electrode 1 and the machining object W can be relatively scanned, the electrode 1 is moved by the XY drive mechanism to move the machining object W, that is, the chamber 3. It may be fixed. In the case of this configuration, the dielectric plate 9 must be sufficiently wider than the machined surface of the machined object W. Further, when the dummy substrate is installed around the object W to be processed, it is necessary to scan a part of the dummy substrate, so that the dielectric plate 9 requires a large area.

Alternatively, although not shown, the scanning means 6 is provided in the chamber 3 with the sample table 7 placed on the upper surface, driven by the numerical control device 12, and placed on the electrode 1 while maintaining the gap G. On the other hand, it may be configured by an XY stage for moving the sample table 7. In this case, since the electrode 1 and the chamber 3 can be fixed, it is only necessary to provide the dielectric plate 9 in a narrow range corresponding to the electrode 1.

In the present embodiment, the high frequency power supply 2 uses an RF power supply having a frequency of 13.56 MHz. The frequency of the high frequency power supply 2 is preferably 0.01 to 200 MHz.

The exhaust system 4 includes a vacuum pump 13, a pressure adjusting valve 14, and a pressure gauge 15. Further, the gas supply system 5 is composed of a gas cylinder filled with constituent gases of various process gases and a gas mixer provided with a flow rate adjusting function. The pipes connected to the exhaust system 4 and the pipes connected to the gas supply system 5 are provided facing each other on both sides of the chamber 3 so that a constant gas flow is generated inside the chamber 3.

After measuring the surface shape or thickness distribution of the work object W to determine the local removal amount of the surface, the work object W is positioned on the upper surface of the sample table 7 in the chamber 3. set. Then, after the inside of the chamber 3 is evacuated by the exhaust system 4, the process gas is supplied from the gas supply system 5 into the chamber 3 by adjusting the flow rate, and the pressure adjusting valve of the exhaust system 4 is supplied. 14 keeps the pressure in the chamber 3 (second set pressure P2) constant. Then, a high-frequency electric field is applied from the high-frequency power source 2 to the electrode 1, a local plasma based on the process gas is generated in the gap G between the dielectric plate 9 facing the electrode 1 and the workpiece W, and the scanning is performed. By controlling the scanning speed of the XY stage constituting the means 6, the relative positional relationship of the electrode 1 with the machining object W is changed, and the plasma irradiation time (residence time of the unit machining mark) at an arbitrary place on the machining object W is changed. ) Is controlled to correct the desired shape or thickness distribution.

<Relationship between machining gap and machining speed>
First, the change in the processing speed due to the size of the gap G between the dielectric plate 9 and the object to be processed W was compared with the static processing marks. The object to be processed W is a quartz glass substrate having a thickness of 6.35 mm. The electrode 1 is a cylinder having a diameter of 3 mm. The dielectric plate 9 is an alumina plate having a thickness of 5 mm. The distance between the electrode 1 and the alumina plate is 0.5 mm. The process gas used was _{a mixed gas of He, SF 6} and O ₂ , and the flow rates were 100 sccm for He, _{30 sccm for SF 6 and} 4 sccm for O ₂ , respectively. The electrode 1 is open to the atmosphere, and the second set pressure P2 in the chamber 3 is 150 Torr. The input power of the high frequency power supply 2 is 230 W. Then, the gap G was changed to 8 mm, 9 mm, 10 mm, and 11.65 mm. The processing time is constant and is 60 seconds. These processing conditions are summarized in Table 1.

FIG. 2 shows the profile of the unit machining mark for each machining gap, the horizontal axis shows the position (mm), and the vertical axis shows the machining depth (nm). Further, FIG. 3 shows the result of FIG. 2 with a machining gap (mm) on the horizontal axis and MRR (mm ³ / min) on the vertical axis, and MRR shows the volume removal rate (machining speed). .. As a result, it was found that the maximum machining speed was obtained in this experimental device when the machining gap was 10 mm.

<Comparison of processing speed between atmospheric pressure plasma CVM and decompression plasma CVM>
Next, the processing speeds of the conventional atmospheric pressure plasma CVM and the reduced pressure plasma CVM of the present invention were compared with the static processing marks. The object to be processed W is a quartz glass substrate having a thickness of 6.35 mm. The electrode nozzle 20 of the atmospheric pressure plasma CVM device has a structure in which an electrode 21 having a diameter of 3 mm is arranged at the center of the gas supply pipe 22, and the processing gap is a direct distance between the tip of the electrode nozzle 20 and the quartz glass substrate. Is.

The processing conditions are shown in Table 2. In the atmospheric pressure plasma CVM, the process gas used is _{a mixed gas of He, CF 4} , and O ₂ , and the flow rates are 700 sccm for He, 20 sccm for _{CF 4 , and 2.5 sccm for O 2} , respectively, and the pressure is atmospheric pressure. (760Torr), the processing gap is 1.9 mm, and the input power is 55 W. On the other hand, low-pressure plasma CVM of the present invention, the process gas used is _Ar, a mixture gas of SF 6, _{O 2,} flow rate each Ar is 100 sccm, SF ₆ is 45 sccm, _{O 2} is 4.0Sccm, The electrode 1 is open to the atmosphere, the second set pressure P2 in the chamber 3 is 80 Torr, the processing gap is 10 mm, and the input power is 230 W. In both cases, the processing time is 60 seconds.

This result is shown in FIG. While the processing speed of the conventional atmospheric pressure plasma CVM was 0.068 mm ³ / min, the processing speed of the decompression plasma CVM of the present invention was 2.6 mm ³ / min, which is a 38-fold improvement. rice field. This is largely due to the fact that the present invention can stably maintain the plasma even if the input power is increased. Further, it is presumed that the mean free path is longer in the decompression plasma than in the atmospheric pressure plasma, the decomposition of the reaction gas is effectively promoted, and the radical density is increased. Incidentally, the mean free path of electrons in the atmospheric pressure plasma is 1.10 μm, whereas the mean free path of electrons in the vacuum plasma of 100 Torr is 8.33 μm.

<Change in processing amount at the edge of the substrate>
Next, changes in the amount of processing at the substrate end of the conventional atmospheric pressure plasma CVM and the reduced pressure plasma CVM of the present invention were compared. The experimental arrangement of the atmospheric pressure plasma CVM is shown in FIG. A sample table 24 was placed on the XY stage 23, and a quartz glass substrate W on the left side and a dummy substrate D of the same material and the same thickness on the right side were held at intervals of 0.5 mm. The experimental arrangement of the reduced pressure plasma CVM of the present invention is shown in FIG. The sample table 7 was placed on the XY stage which is the scanning means 6, and the quartz glass substrate W on the left side and the dummy substrate D of the same material and the same thickness on the right side were held at intervals of 0.5 mm. .. FIG. 7 shows the scanning range 25 of the local plasma generation region LP, and is located at a position 30 mm (central portion) from the edge of the quartz glass substrate W and a position (edge portion) 1 mm from the edge after predetermined processing. The processing speeds were compared. The processing conditions are the same as those shown in Table 2 above. The scanning speed is 500 mm / min, the number of round trips is 30, and the scanning range is 80 mm.

The processing result of the conventional atmospheric pressure plasma CVM is shown in FIG. 8, and the processing result of the reduced pressure plasma CVM of the present invention is shown in FIG. As a result, in the atmospheric pressure plasma CVM, the processing amount at the end portion and the central portion was significantly different, and the processed cross-sectional area was 29.4% larger than that at the central portion. Further, an arc discharge was generated in the gap between the quartz glass substrate W and the dummy substrate D, and it shined very brightly. This means that even if the dummy substrate D is installed on the outer peripheral portion, the plasma becomes unstable at the end portion of the quartz glass substrate W. On the other hand, in the reduced pressure plasma CVM of the present invention, the machining amount of the end portion is slightly larger than that of the central portion, but the machining amount error is as small as 8% in the machining cross-sectional area. That is, it was confirmed that the present invention is also excellent in processing stability at the end portion of the object to be processed W.

Further, according to the present invention, the machining speed and the profile of the unit machining mark can be easily changed by changing the machining conditions. That is, by changing the input power of the high frequency power supply 2, the size of the second set pressure P2, the type and composition of the process gas, etc., while the processing object W is set in the processing apparatus and the gap G is kept constant. , The processing speed can be changed. Therefore, with the machining object W set in the machining equipment, it is possible to perform a series of machining from rough machining with a high machining speed to precision machining with a slow machining speed, thereby removing components with a short space wavelength from components with a long space wavelength. Can be done.

The present invention is characterized in that plasma, which was conventionally generated under atmospheric pressure, is generated under a reduced pressure of about 1/10 atm. Plasma under a low pressure of 1 Torr or less is used in the process of manufacturing semiconductor devices, but it is a process of generating a uniform plasma over a wide range and using a mask formed on the substrate to produce a fine pattern. On the other hand, the present invention is intended to be used for maskless shape correction and uniform film thickness of a large substrate by numerically controlled scanning of locally generated plasma, and the processing principle and purpose are completely different. .. Further, the present invention has an extremely simple structure in which only the substrate to be processed is arranged in a small vacuum chamber. Further, while the size of the plasma region in the process is fixed in the competitive technology, in the present invention, the size of the local processing region can be widely changed even in the process by power control, and the size of the local processing region can be widely changed in the processing object. It is possible to process the removal of spatial wavelength components.

10 and 11 show the first embodiment of the present invention, in which a large plate-shaped object W to be machined can be machined by locally performing differential exhaust. In the present embodiment, the chamber 30 is not a closed type, but has openings 31 and 31 on both sides through which the object W to be processed can pass, and while the object W to be processed passes from one opening 31 to the other opening 31. It is designed to be processed. Here, the chamber 30 is partitioned by a partition wall 32 from the side surface to the lower surface and the upper surface, and a part or all of the upper surface is formed of a dielectric plate 33 made of ceramics, and the atmosphere on the dielectric plate 33 is formed. The electrodes 34 are arranged in a non-contact state under the open position, and the electrodes 34 can be numerically controlled and scanned by a drive mechanism (not shown) at least in a direction orthogonal to the feeding direction of the workpiece W. Further, the chamber 30 is provided with a plasma generation chamber 35 in the central portion thereof, exhaust chambers 36 and 36 are provided on both sides thereof, and process gas is supplied to the plasma generation chamber 35 from a gas supply system (not shown). However, exhaust is exhausted from both exhaust chambers 36 and 36 by a large-capacity exhaust system (not shown) to form a differential exhaust structure, and the plasma generation chamber 35 is brought into a predetermined depressurized state. It is more preferable that the openings 31 and 31 of the chamber 30 are provided with a sealing material that elastically closes the gap between the chamber 30 and the object W to be processed.

12 and 13 show a second embodiment of the present invention, and also in this embodiment, the large plate-shaped object W to be machined can be machined by locally differential exhausting. That is, in the present embodiment, the electrode pad 40 is machined by numerically controlling and scanning the surface of the object W to be machined in a large area. An electrode 41 coated with ceramics is arranged in the center of the electrode pad 40, a gas ejection pipe 42 for process gas is concentrically formed around the electrode pad 40, and gas suction pipes 43 and 44 are formed on the outer side in a plurality of ways. The structure is such that the electrode 41 is formed substantially flat, the electrode 41 is slightly retracted, and a predetermined gap is formed between the tip thereof and the object W to be machined. A gas supply pipe 45 is connected to the gas ejection pipe 42 to supply process gas, and a large-capacity exhaust system (not shown) is provided by the gas exhaust pipes 46 and 47 connected to the gas suction pipes 43 and 44. ) Is exhausted to form a differential exhaust structure, the space (gap) between the electrode 41 and the object W to be machined is reduced to a reduced state, and plasma is generated in the space.

The present invention is applied to flattening a photomask substrate for a lithography process, uniformizing the thickness distribution of a crystal wafer, uniformizing the characteristics of a large number of SAW (Surface Acoustic Wave) devices manufactured on a wafer, uniformizing an SOI layer, and the like. can.

1 electrode,
2 high frequency power supply,
3 chambers,
4 Exhaust system,
5 Gas supply system,
6 Scanning means,
7 Sample stand,
8 compartment walls,
9 Dielectric plate,
10 base plate,
11 Gap adjusting means,
12 Numerical control device,
13 Vacuum pump,
14 Pressure regulation valve,
15 Pressure gauge,
20 electrode nozzle,
21 electrodes,
22 Gas supply pipe,
23 stages,
24 Sample stand,
25 scanning range,
30 chambers,
31 openings,
32 compartment walls,
33 Dielectric plate,
34 electrodes,
35 Plasma generation chamber,
36 Exhaust chamber,
40 electrode pad,
41 electrodes,
42 gas ejection pipe,
43 Gas suction tube,
44 gas suction tube,
45 gas supply pipe,
46 gas exhaust pipe,
47 gas exhaust pipe,
W Machining object,
D dummy board,
G gap,
LP local plasma generation area,
S1 first space,
S2 second space,
P1 1st set pressure,
P2 2nd set pressure,

Claims (5)

It is a non-sealed plasma processing device that is placed under the open air and forms a plasma generation space with the surface of a plate-shaped object to be processed.
It is partitioned by a partition wall from the side surface to the lower surface and the upper surface, and a part or all of the upper surface is formed of a dielectric plate made of plasmamics to form openings on both sides through which the object to be processed can pass. A non-sealed chamber with a plasma generation chamber that serves as a plasma generation space and exhaust chambers on both sides of the chamber.
An electrode placed in a non-contact state on the dielectric plate under the open atmosphere,
A gas supply system that supplies a process gas containing a reaction gas to the plasma generation space,
A gas exhaust system having a differential exhaust structure that exhausts the process gas and the atmosphere from both exhaust chambers to maintain the pressure in the plasma generation space in a reduced pressure state of 20 to 200 Torr.
A high-frequency power supply that applies a high-frequency electric field to the electrodes,
The surface of the object to be processed is treated with the plasma generated in the plasma generation space while the object to be processed passes from one opening to the other opening.
A plasma processing device characterized by this. Wherein the opening of the chamber, the workpiece and the gap is provided a sealing member for closing elastically to the plasma processing apparatus according to claim 1. The plasma processing apparatus according to claim 1 or 2 , wherein the electrodes can be numerically controlled and scanned by a drive mechanism at least in a direction orthogonal to the feed direction of the object to be machined. It is a non-sealed plasma processing device that is placed under the open air and forms a plasma generation space with the surface of a plate-shaped object to be processed.
A plasma-coated electrode is placed in the center, a gas ejection tube for process gas containing reaction gas concentrically is formed around it, and multiple gas suction tubes are formed on the outside, and the lower surface is formed substantially flat. Is located slightly retracted from the gas ejection pipe, and has an electrode pad having a structure that forms a predetermined gap that serves as the plasma generation space between the tip thereof and the object to be processed.
A gas supply system including a gas supply pipe connected to the gas ejection pipe and supplying process gas from the gas supply pipe to the plasma generation space through the gas ejection pipe.
Differences including a gas exhaust pipe connected to the gas suction pipe , in which the process gas and the atmosphere are exhausted through the gas suction pipe, and the pressure in the plasma generation space is maintained in a reduced pressure state of 20 to 200 Torr. A gas exhaust system with a dynamic exhaust structure and
A high-frequency power supply that applies a high-frequency electric field to the electrodes,
The electrode pad is numerically controlled and scanned along the surface of the object to be machined, and the surface of the object to be machined is treated with the plasma generated in the plasma generation space.
A plasma processing device characterized by this. The plasma treatment according to any one of claims 1 to 4 , wherein the process gas is a mixed gas of a rare gas and a halogen element-containing gas or an oxygen gas, and the creation of the surface shape of the object to be processed is a removal process. Device.

Images