JP2010277902A - Plasma-processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma-processing device by which the processed region of a processed object is evenly processed. <P>SOLUTION: The plasma-processing device 1002 scans a workpiece 1902 supported by a first electrode structure 1004 having a first electrode 1012 comprising a first opposing surface 1020 with the same planar shape as that of the processed region 1908, by means of a second electrode structure 1036 having a second electrode 1046 comprising a linear second opposing surface 1050. Further, the device 1002 actuates the plasma onto the upper surface 1904 of the workpiece 1902, by applying a voltage between the first electrode 1012 and the second electrode 1046 while scanning the workpiece 1902 by the second electrode structure 1036, and generating the plasma in a gap 1038 between the first electrode structure 1004 and the second electrode structure 1036. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus for processing a processing region that occupies a part of the surface of a processing target.

  Patent Document 1 relates to a plasma processing apparatus (surface processing apparatus 30) that processes a processing target region (concave portion 9) that occupies a part of the surface of a processing target (glass substrate 2 formed up to bank B). The plasma processing apparatus disclosed in Patent Document 1 includes a first electrode (mounting table 32) having a support surface for supporting an object to be processed, a second electrode (high frequency application electrode 40), an object to be processed, and a second electrode. And a third electrode (pattern electrode film 36) having a planar shape corresponding to the planar shape of the region to be processed.

JP 2006-173486 A

  In the plasma processing apparatus of Patent Document 1, when the object to be processed is enlarged, the area where the electrodes face each other is widened, so that the uniformity of discharge is deteriorated and the region to be processed of the object to be processed is not uniformly processed.

  The present invention has been made to solve this problem, and an object of the present invention is to provide a plasma processing apparatus in which a region to be processed of an object to be processed is processed uniformly.

  In order to solve the above problems, the following means are provided.

  The first plasma processing apparatus includes a first electrode having a first opposing surface having a planar shape corresponding to a planar shape of a region to be processed on the surface of the workpiece, and has a support surface that supports the workpiece. A first electrode structure, a second electrode structure including a second electrode having a linear second facing surface, one output end connected to the first electrode, and the other output end A direction different from a direction in which the second facing surface extends via a power source connected to the second electrode and a facing position where the first facing surface and the second facing surface face each other. A transport mechanism that moves the second electrode structure relative to the first electrode structure, and a relative position of the second electrode structure relative to the first electrode structure is at the facing position. A processing gas supply for supplying a processing gas to a gap between the first electrode structure and the second electrode structure It includes a structure, a.

  The second plasma processing apparatus further includes an output adjustment mechanism that, in the first plasma processing apparatus, increases an output of the power source as a facing area between the first facing surface and the second facing surface increases. .

  The third plasma processing apparatus is the second plasma processing apparatus, wherein the output adjustment mechanism detects a relative position of the second electrode structure with respect to the first electrode structure; A storage device for storing information for specifying a relationship between a relative position of the second electrode structure with respect to the first electrode structure and a facing area between the first facing surface and the second facing surface; A control unit that acquires a detection result of the relative position detector, reads information specifying the relationship between the relative position and the facing area from the storage device, and controls the output of the power source.

  The fourth plasma processing apparatus is the second plasma processing apparatus, wherein the power source is a pulse power source, and the output adjusting mechanism is an electric pulse applied between the first electrode and the second electrode. A peak voltage detector that detects the peak voltage of the power supply, and a controller that acquires the detection result of the peak voltage detector and controls the output of the power source.

  The fifth plasma processing apparatus is the second plasma processing apparatus, wherein the output adjustment mechanism acquires a photodetector that detects plasma light radiated from the gap, a detection result of the photodetector, and the power source. And a control unit for controlling the output of.

  The sixth plasma processing apparatus is the fifth plasma processing apparatus, wherein the photodetector detects the intensity and spread of the plasma light, and the control unit increases the output of the power source as the intensity of the plasma light increases. The output of the power source is increased as the spread of the plasma light is increased.

  The seventh plasma processing apparatus is the first plasma processing apparatus, wherein the power source is a pulse power source.

  An eighth plasma processing apparatus is the seventh plasma processing apparatus, wherein the pulse power source is an inductive energy storage type.

  According to the present invention, since the facing area between the first facing surface of the first electrode and the second facing surface of the second electrode is narrowed, the uniformity of discharge is improved, and the processing object is processed. The area is processed uniformly.

  According to the second to sixth aspects of the present invention, the fluctuation of the output of the power supply per unit area of the region where the first facing surface of the first electrode and the second facing surface of the second electrode are opposed to each other. The processing area of the object to be processed is more uniformly processed.

  According to the invention of claim 8, since the streamer discharge is generated in the gap between the first electrode structure and the second electrode structure, the region to be processed of the object to be processed is more uniformly processed.

It is a perspective view of the plasma processing apparatus of 1st Embodiment. It is a perspective view of a workpiece. It is a perspective view of the 1st electrode structure. It is sectional drawing of a reactor. It is a perspective view of the 2nd electrode structure. It is a perspective view of a processing gas supply body. It is a figure which shows the rough waveform of an IES pulse and a CES pulse. It is a figure which shows the rough waveform of an IES pulse and a CES pulse. It is a figure which shows the rough waveform of an IES pulse and a CES pulse. It is a circuit diagram of an IES power supply. It is a schematic diagram which shows the state of streamer discharge. It is a schematic diagram which shows the state of streamer discharge. It is a block diagram of the output adjustment mechanism of 2nd Embodiment. It is a block diagram of the output adjustment mechanism of 3rd Embodiment. It is a circuit diagram of a peak hold circuit. It is a circuit diagram of a voltage comparison circuit. It is a block diagram of the output adjustment mechanism of 4th Embodiment. It is a perspective view of the 2nd electrode structure of a 5th embodiment. It is a perspective view of the 1st electrode structure of a 6th embodiment. It is a perspective view of the 1st electrode structure of a 7th embodiment.

(1. First embodiment)
(Outline of plasma processing apparatus 1002)
The first embodiment relates to a plasma processing apparatus 1002 that processes a processing area 1908 that occupies a part of the upper surface 1904 of a work 1902. The plasma processing apparatus 1002 of the first embodiment is supported by a first electrode structure 1004 including a first electrode 1012 having a first facing surface 1020 having the same planar shape as the planar shape of the processing target region 1908. The workpiece 1902 is scanned with a second electrode structure 1036 including a second electrode 1046 having a linear second opposing surface 1050. In addition, the plasma processing apparatus 1002 applies an electric pulse between the first electrode 1012 and the second electrode 1046 while scanning the upper surface 1904 of the work 1902 with the second electrode structure 1036, thereby Plasma is generated in a gap 1038 between the structure body 1004 and the second electrode structure body 1036, and plasma is applied to the upper surface 1904 of the work 1902. At this time, since discharge selectively occurs in a region where the first facing surface 1020 and the second facing surface 1050 face each other, the processing target region 1908 of the workpiece 1902 is selectively processed.

(Structure of plasma processing apparatus 1002)
FIG. 1 is a schematic diagram of a plasma processing apparatus 1002 according to the first embodiment. FIG. 1 is a perspective view of the plasma processing apparatus 1002.

  As shown in FIG. 1, the plasma processing apparatus 1002 processes a first electrode structure 1004 that supports a work 1902, a transport mechanism 1006 that transports the first electrode structure 1004, and an upper surface 1904 of the work 1902. A reactor 1008 and a pulse power source 1010 that supplies electric pulses to the reactor 1008 are provided. Although the advantages described later are lost, a high frequency power supply may be employed instead of the pulse power supply 1010.

(Work 1902 and purpose of processing)
FIG. 2 is a schematic diagram of a work 1902 processed by the plasma processing apparatus 1002. FIG. 2 is a perspective view of the workpiece 1902. The work 1902 is a glass substrate for a flat panel display.

  As shown in FIG. 2, the work 1902 has a rectangular plate shape. A light emitting layer 1906 is regularly arranged in the vertical direction and the horizontal direction on the upper surface 1904 of the work 1902.

  The plasma processing apparatus 1002 processes a lattice-shaped target region 1908 on the upper surface 1904 of the workpiece 1902 where the light emitting layer 1906 is not formed, and improves the wettability of the target region 1908.

  The work 1902 is not limited to a glass substrate for a flat panel display. Therefore, the workpiece 1902 may be a glass substrate other than a semiconductor substrate, a glass substrate for a flat panel display, or the like.

  The planar shape of the processing target region 1908 is not limited to the lattice shape. Accordingly, the planar shape of the region to be processed 1908 is arbitrary.

  The purpose of the treatment is not limited to the improvement of wettability. Therefore, cleaning for removing contamination attached to the surface, etching for eroding the surface, ashing for ashing a fluorine compound film or other film formed on the surface may be used.

(First electrode structure 1004)
FIG. 3 is a schematic diagram of the first electrode structure 1004. FIG. 3 is a perspective view of the first electrode structure 1004. The “electrode structure” is a structure that includes at least an electrode and is provided with a dielectric barrier or the like as necessary.

  As shown in FIG. 3, the first electrode structure 1004 has a plate shape. The first electrode structure 1004 includes a first dielectric that covers the first electrode 1012, the holder 1014 that holds the first electrode 1012, and the first facing surface (upper surface) 1020 of the first electrode 1012. A barrier 1016. The holder 1014 and the first dielectric barrier 1016 may be made of the same insulating material and integrated. When the holder 1014 and the first dielectric barrier 1016 are integrated, the first electrode 1012 is embedded in an integrated body of the holder 1014 and the first dielectric barrier 1016.

  The first electrode 1012 is made of a conductive material such as aluminum, copper, or stainless steel. The first electrode 1012 has a plate shape or a film shape. The planar shape of the first electrode 1012 is a planar shape corresponding to the planar shape of the processing target region 1908 of the workpiece 1902, that is, a lattice shape. The first electrode 1012 is a partial electrode that occupies a part of the support region 1018 of the work 1902, not a full surface electrode that occupies the entire support region 1018 in contact with the lower surface 1910 of the work 1902.

  Regarding the planar shape of the first electrode 1012, the planar shape of the first facing surface 1020 that mainly contributes to the discharge is important. Accordingly, the first facing surface 1020 of the first electrode 1012 has a planar shape corresponding to the planar shape of the processing target region 1908 of the workpiece 1902 and occupies a part of the support region 1018 of the workpiece 1902. That's enough. The first facing surface 1020 is desirably flat.

  The holder 1014 is made of an insulating material such as glass or alumina. The holder 1014 has a plate shape. When the first electrode 1012 has a plate shape, an accommodation hole 1024 having substantially the same three-dimensional shape as the first electrode 1012 is formed on the upper surface 1022 of the holder 1014 (see FIG. 4). The first electrode 1012 is accommodated in the accommodation hole 1024. In the state where the first electrode 1012 is accommodated in the accommodation hole 1024, the first facing surface 1020 of the first electrode 1012 and the portion of the upper surface 1022 of the holder 1014 where the accommodation hole 1024 is not formed have the same flat surface. Constitute.

  The first dielectric barrier 1016 is made of an insulating material such as glass or alumina. The first dielectric barrier 1016 has a plate shape. The first dielectric barrier 1016 has the same planar shape as the holder 1014. The first dielectric barrier 1016 is placed on the first facing surface 1020 of the first electrode 1012 and the upper surface 1022 of the holder 1014. The first dielectric barrier 1016 protects the first electrode 1012 and suppresses the occurrence of arc discharge.

  The upper surface of the first dielectric barrier 1016 (the upper surface of the first electrode structure 1004) 1025 is flat. Note that the entire upper surface 1025 of the first dielectric barrier 1016 does not need to be flat, and it is sufficient if the support region 1018 is flat. Accordingly, the work 1902 having a flat bottom surface 1910 is appropriately supported on the top surface 1025 of the first dielectric barrier 1016. When the lower surface 1910 of the work 1902 is not flat, the support region 1018 on the upper surface 1025 of the first dielectric barrier 1016 has unevenness opposite to the unevenness of the lower surface 1910 of the work 1902.

  The plate thickness of the first dielectric barrier 1016 is desirably 0.5 to 5 mm. This is because if the plate thickness of the first dielectric barrier 1016 is less than this range, arc discharge tends to occur, and if the plate thickness exceeds this range, the first electrode 1012 and the second electrode 1046 may not be easily affected. This is because the capacitance between the first electrode 1012 and the second electrode 1046 tends to be difficult to apply a fast rising electric pulse.

(Transport mechanism 1006)
As shown in FIG. 1, the transfer mechanism 1006 moves from the transfer start position 1026 outside the reactor 1008 through the carry-in port 1028 of the reactor 1008, the inside of the reactor 1008, and the carry-out port 1030 of the reactor 1008 (see FIG. 4). The first electrode structure 1004 on which the work 1902 is placed is linearly conveyed to the external conveyance end position 1032.

  The transport mechanism 1006 extends the long carrier 1034 on which the first electrode structure 1004 is placed from the transport start position 1026 to the transport end position 1032 through the transport inlet 1028, the inside of the reactor 1008 and the transport outlet 1030. The carrier 1034 is caused to travel in the extending direction. A non-elongation in which the first electrode structure 1004 is placed along a guide member such as a rail that extends from the transfer start position 1026 to the transfer end position 1032 through the transfer inlet 1028, the inside of the reactor 1008, and the transfer outlet 1030. A transport mechanism for moving the carrier or the first electrode structure 1004 itself is also employed.

  Two or more first electrode structures 1004 on which the workpiece 1902 is placed may be arranged in the transport direction, and a plurality of workpieces 1902 may be processed continuously. In addition, two or more workpieces 1902 may be placed on one first electrode structure 1004.

(Reactor 1008)
FIG. 4 is a schematic diagram of the reactor 1008. FIG. 4 is a cross-sectional view of the reactor 1008.

  As shown in FIG. 4, the reactor 1008 includes a second electrode structure 1036 and a gap between the first electrode structure 1004 and the second electrode structure 1036 that passes below the second electrode structure 1036. 1038 includes a processing gas supply body 1040 for supplying a processing gas to 1038, a distance adjusting body 1042 for adjusting the distance between the second electrode structure 1036 and the processing gas supply body 1040, and a housing 1044 for housing them.

(Second electrode structure 1036)
FIG. 5 is a schematic diagram of the second electrode structure 1036. FIG. 5 is a perspective view of the second electrode structure 1036.

  As shown in FIG. 5, the second electrode structure 1036 has a plate shape. The second electrode structure 1036 includes a second electrode 1046 and a second dielectric barrier 1048 that covers the surface of the second electrode 1046.

  The second electrode 1046 is made of a conductive material such as aluminum, copper, or stainless steel. The second electrode 1046 has a plate shape. The second electrode 1046 is installed perpendicular to the first electrode 1012. Therefore, the second opposing surface (lower end surface) 1050 of the second electrode 1046 is a linear elongated surface extending in a direction parallel to the first opposing surface 1020 of the first electrode 1012. The “linear elongated surface” refers to a second direction parallel to the first facing surface 1020 of the first electrode 1012 and perpendicular to the extending direction of the second facing surface 1050 of the second electrode 1046. The size of the second facing surface 1050 of the electrode 1046 is at least smaller than the size of the first facing surface 1020 of the first electrode 1012, preferably 1 / th of the size of the first facing surface 1020 of the first electrode 1012. It means 10 or less. Accordingly, since the facing area between the first facing surface 1020 of the first electrode 1012 and the second facing surface 1050 of the second electrode 1046 is reduced, the uniformity of discharge is improved. Further, since the upper surface 1094 of the workpiece 1092 is scanned by the second electrode structure 1036, the entire processing target region 1908 is processed. As a result, the entire processing area 1908 of the workpiece 1092 is processed uniformly.

  “Scanning” refers to moving the second electrode structure 1036 relative to the upper surface 1094 of the work 1092 along the upper surface 1094 of the work 1092. The term “opposing” means that the first opposing surface 1020 and the second opposing surface overlap when viewed from the normal direction of the first opposing surface 1020, and “opposing area” means The area of the overlapping region.

  The plate thickness of the second electrode 1046 is desirably 1 to 20 mm.

  The second dielectric barrier 1048 is made of an insulating material such as glass or alumina. The second dielectric barrier 1048 has a sheath shape having an elongated rectangular opening on the upper surface. The second dielectric barrier 1048 is formed with a receiving hole 1037 having a substantially same three-dimensional shape as the second electrode 1046 (see FIG. 4). The accommodation hole 1037 accommodates the second electrode 1046 in parallel to the main surface of the second dielectric barrier 1048. The second dielectric barrier 1048 shown in FIG. 5 accommodates the entire second electrode 1046, but it is the second opposing surface 1050 of the second electrode 1046 that mainly contributes to the generation of discharge. Therefore, there is no problem even if the second dielectric barrier 1048 is accommodated only in the vicinity of the second facing surface 1050 of the second electrode 1046. The second dielectric barrier 1048 protects the second electrode 1046 and suppresses the occurrence of arc discharge.

  The thickness of the portion covering the second facing surface 1050 of the second dielectric barrier 1048 is desirably 0.5 to 5 mm. This is because when the thickness of the second dielectric barrier 1048 is less than this range, arc discharge tends to occur. When the thickness is greater than this range, the first electrode 1012 and the second electrode 1046 This is because the capacitance between the first electrode 1012 and the second electrode 1046 tends to be difficult to apply a fast rising electric pulse.

  FIG. 4 shows a case where the reactor 1008 includes two second electrode structures 1036, but the number of second electrode structures 1036 may be increased or decreased.

(Conveying direction of first electrode structure 1004)
The transport direction of the first electrode structure 1004 is different from the extending direction of the second facing surface 1050 of the second electrode 1040, and the extending direction of the second facing surface 1050 of the second electrode 1040. It is desirable that the direction is 90 ° different from the direction. When the first electrode structure 1004 that supports the work 1902 is transported by the transport mechanism 1006, the first electrode structure 1004 that supports the work 1902 is below the second electrode structure 1036, that is, the first The first opposing surface 1020 of the electrode 1012 and the second opposing surface 1050 of the second electrode 1046 move through opposing positions that are separated from each other in the vertical direction, and the workpiece 1902 is moved by the second electrode structure 1036. The top surface 1910 is scanned.

  Instead of transporting the first electrode structure 1004, by transporting the second electrode structure 1036, or by transporting the first electrode structure 1004 and the second electrode structure 1036. The second electrode structure 1036 may be moved relative to the first electrode structure 1004. In these cases, the relative movement direction of the second electrode structure 1036 with respect to the first electrode structure 1004 is different from the extending direction of the second facing surface 1050 of the second electrode 1040, and the second It is desirable that the direction of the second facing surface 1050 of the electrode 1040 be 90 ° different from the extending direction.

  Further, the transport direction of the first electrode structure 1004 is a direction parallel to the first facing surface 1020 of the first electrode 1012. Thus, the distance between the first facing surface 1020 of the first electrode 1012 and the second facing surface 1050 of the second electrode 1046 is kept constant, and the workpiece 1902 is processed uniformly.

(Processing gas supplier 1040)
FIG. 6 is a schematic diagram of the processing gas supply body 1040. FIG. 6 is a perspective view of the processing gas supply body 1040.

  As shown in FIG. 6, the processing gas supply body 1040 has a substantially rectangular parallelepiped outer shape, and a gas reservoir 1052 for retaining the processing gas and a flow for guiding the processing gas from the upper surface 1054 to the gas reservoir 1052 are contained therein. A channel 1056 and a channel 1060 for guiding the processing gas from the gas reservoir 1052 to the lower surface 1058 are formed. In addition, a shower plate 1062 is installed in the processing gas supply body 1040 in contact with the gas reservoir 1052. In the shower plate 1062, through holes having a diameter of 0.1 to 1 mm are regularly formed at intervals of 1 to 20 mm. Instead of the shower plate 1062, a pressure loss member having a large number of through holes, for example, a mesh laminate or a ceramic porous body may be employed.

  The processing gas supply unit 1040 passes the processing gas supplied from the processing gas supply source through the flow path 1056, the gas reservoir 1052, the shower plate 1062, and the flow path 1060 in order, and makes the flow of the processing gas uniform. A processing gas is ejected from an outlet 1064 having a shape. Accordingly, the gap 1038 between the first electrode structure 1004 and the second electrode structure 1036 below the second electrode structure 1036, that is, the second electrode structure relative to the first electrode structure 1012. The first electrode structure 1004 and the second electrode 1046 when the relative position of 1046 is at the opposing position where the first opposing surface 1020 of the first electrode 1012 and the second opposing surface 1050 of the second electrode 1046 oppose each other. A processing gas is supplied to a gap 1038 between the electrode structure 1036 and the electrode structure 1036.

(Distance adjustment body 1042)
The distance adjuster 1042 is made of a highly rigid insulating material such as glass or alumina. The distance adjusting body 1042 has a rectangular parallelepiped shape. Since the distance between the outlet 1064 and the gap 1038 is increased by the distance adjusting body 1042, the flow of the processing gas is made uniform until the processing gas reaches the gap 1038, and the processing area 1908 of the workpiece 1902 is processed uniformly. .

(Composition of processing gas)
The processing gas is desirably a gas mainly composed of nitrogen gas, and is desirably a gas composed of only nitrogen gas or a mixed gas composed of nitrogen gas and oxygen gas. When a mixed gas composed of nitrogen gas and oxygen gas is used as the processing gas, it is desirable that the content of oxygen gas in the whole is 1-4% by volume. This is because if the oxygen gas content is within this range, the efficiency of the treatment is improved. The pressure inside the reactor 1008 may be near atmospheric pressure.

(Omit the dielectric barrier)
In the reactor 1008 shown in FIG. 4, both the first electrode structure 1004 and the second electrode structure 1036 are provided with a dielectric barrier, but the first electrode structure 1004 and the second electrode structure are not provided. Only one of 1036 may be provided with a dielectric barrier.

(Form of pulse power supply 1010)
The pulse power source 1010 is not particularly limited as long as it is a power source that applies an electric pulse that generates a streamer discharge without generating an arc discharge between the first electrode 1012 and the second electrode 1046. An inductive energy storage (IES) power source (hereinafter referred to as “IES power source”) that releases energy stored in the form of a magnetic field in a short time is desirable. This is because the IES power supply is compared with a capacitive energy storage (CES) power supply (hereinafter referred to as “CES power supply”) that discharges energy stored in the form of an electric field in the capacitive element in a short time. This is because remarkably large energy can be input to the reactor 1008. Typically, when the electrode structure is the same, when an IES power supply is employed, the energy per pulse used for the reaction for generating plasma (hereinafter referred to as “one pulse energy”) is a CES power supply. Approximately one order of magnitude larger than the case. This difference between the IES power supply and the CES power supply is caused by the fact that the electric pulse generated by the IES power supply has a rapid increase in voltage, whereas the electric pulse generated by the CES power supply has a slow increase in voltage. That is, when the IES power supply is adopted, the discharge starts after the voltage is sufficiently increased, and one pulse energy becomes sufficiently large, whereas when the CES power supply is adopted, the discharge is performed before the voltage is sufficiently increased. This occurs when one pulse energy does not become sufficiently large.

  7 to 9 are diagrams showing schematic waveforms of an electric pulse generated by the IES power supply (hereinafter referred to as “IES pulse”) and an electric pulse generated by the CES power supply (hereinafter referred to as “CES pulse”). . 7A and 7B are voltage waveforms of the IES pulse and the CES pulse, respectively. FIGS. 8A and 8B are current waveforms of the IES pulse and the CES pulse, respectively. (A) and FIG.9 (b) are figures which show the waveform of the product of the voltage and electric current of an IES pulse and a CES pulse, respectively.

  One pulse energy is calculated by integrating the product of voltage and current shown in FIG. 9 with time. As shown in FIG. 7 and FIG. 8, the current flows in the positive direction almost synchronously with the voltage increase, and flows in the negative direction almost synchronously with the voltage decrease. It is proportional to the area obtained by subtracting the area of the region B where the waveform is negative from the area of the region A where the waveform is positive.

(Switching element)
As the IES power supply, it is desirable to employ a power supply using an electrostatic induction thyristor (hereinafter referred to as “SI thyristor”) as a switching element for controlling the supply of current to the inductive element. By using the SI thyristor as a switching element, an electric pulse having a fast rise is generated, and thus the above-described streamer discharge is easily generated. The reason why an electric pulse with a fast rise is generated by using the SI thyristor as a switching element is that the SI thyristor is turned off at a high speed because the gate is not insulated and carriers are extracted from the gate at a high speed. For details on the operating principle of the IES power supply, see, for example, Katsuji Iida, Ken Sakuma: “Ultra-short pulse generation circuit using an SI thyristor (IES circuit)”, SI Device Symposium Proceedings, Vol. 15, Page. 40-45 (issued on June 14, 2002).

(IES power supply 1100)
FIG. 10 is a circuit diagram of an IES power supply 1100 that uses the SI thyristor 1108 as a switching element, which is preferably used for the pulse power supply 1010. Of course, the circuit diagram shown in FIG. 10 is merely an example, and may be modified as necessary.

  As shown in FIG. 10, the IES power source 1100 includes a DC power source 1102 that supplies electric energy and a capacitor 1104 that enhances the discharge capability of the DC power source 1102.

  The voltage of the DC power supply 1102 is allowed to be significantly lower than the peak voltage of the electric pulse generated by the IES power supply 1100. For example, even if the primary side peak voltage of the step-up transformer 1106 to be described later reaches 4 kV, the voltage of the DC power source 1102 may be several tens to several hundreds volts. The lower limit of this voltage is determined by the latching voltage of the SI thyristor 1108 described later. The IES power supply 1100 uses such a low-voltage DC power supply 1102 as an electrical energy source, and thus is constructed in a small size and at a low cost.

  Capacitor 1104 is connected in parallel with DC power supply 1102. Capacitor 1104 enhances the discharge capability of DC power supply 1102 by apparently reducing the impedance of DC power supply 1102.

  The IES power supply 1100 further includes a step-up transformer 1106, an SI thyristor 1108, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 1110, a gate drive circuit 1112 and a diode 1114.

  In the IES power source 1100, the DC power source 1102, the primary side of the step-up transformer 1106, the anode (A) and cathode (K) of the SI thyristor 1108, and the drain (D) and source (S) of the MOSFET 1110 are connected in series. Connected. That is, one end of the primary side of the step-up transformer 1106 is the positive electrode of the DC power supply 1102, the other end of the primary side of the step-up transformer 1106 is the anode of the SI thyristor 1108, and the cathode (K) of the SI thyristor 1108 is the drain of the MOSFET 1110 ( D), the source (S) of the MOSFET 1110 is connected to the negative electrode of the DC power supply 1102. As a result, a current is supplied from the DC power supply 1102 to these circuit elements. In the IES power supply 1100, the gate (G) of the SI thyristor 1108 is connected in parallel with one end on the primary side of the step-up transformer 1106 via the diode 1114. That is, the gate (G) of the SI thyristor 1108 is connected to the anode (A) of the diode 1114, and the cathode (K) of the diode 1114 is connected to one end on the primary side of the step-up transformer 1106 (positive electrode of the DC power supply 1102). A gate drive circuit 1112 is connected between the gate (G) and source (S) of the FET.

  The step-up transformer 1106 further boosts the electric pulse applied to the primary side and outputs it to the secondary side. The primary side of the step-up transformer 1106 is an inductive element having self-inductance.

A load 1116 is connected to the secondary side of the step-up transformer 1106. That is, one output terminal of the secondary side of the step-up transformer 1106 is connected to the first electrode 1012, and the other output terminal is connected to the second electrode 1046. When the first electrode 1012 is grounded and the electric pulse is unipolar, a positive pulse is applied to the second electrode 1136.

  The SI thyristor 1108 is turned on and off in response to a signal applied to the gate (G).

  The MOSFET 1110 is a switching element in which the conduction state between the drain (D) and the source (S) changes in response to a signal given from the gate drive circuit 1112. It is desirable that the on-voltage or on-resistance of MOSFET 1110 be low. Further, the withstand voltage of the MOSFET 1110 needs to be higher than the voltage of the DC power supply 1102.

  The diode 1114 prevents the current that flows when a positive bias is applied to the gate (G) of the SI thyristor 1108, that is, when the SI thyristor 1108 applies a positive bias to the gate (G) of the SI thyristor 1108. It is provided to prevent driving.

(Outline of operation of IES power supply 1100)
When an electric pulse is generated in the IES power supply 1100, first, an ON signal is given from the gate drive circuit 1112 to the gate of the MOSFET 1110, and the drain (D) and source (S) of the MOSFET 1110 are brought into conduction. Then, the SI thyristor 1108 is a normally-on type switching element, and the anode (A) and the cathode (K) of the SI thyristor 1108 are in a conductive state, so that a current flows to the primary side of the step-up transformer 1106. In this state, since a positive bias is applied to the gate (G) of the SI thyristor 1108, the conduction state between the anode (A) and the cathode (K) of the SI thyristor 1108 is maintained.

  Subsequently, the application of the ON signal from the gate drive circuit 1112 to the MOSFET 1110 is stopped, and the drain (D) and the source (S) of the MOSFET 1110 are turned off. Then, carriers are discharged from the gate (G) of the SI thyristor 1108 at a high speed by current driving, and the anode (A) and cathode (K) of the SI thyristor 1108 are in a non-conductive state. Current flow is stopped at high speed. As a result, an induced electromotive force is generated on the primary side of the step-up transformer 1106, and a high voltage is generated on the secondary side of the step-up transformer 1106.

(Principle of processing)
The plasma processing apparatus 1002 allows the gap between the first electrode structure 1004 and the second electrode structure 1036 to be repeatedly applied between the first electrode 1012 and the second electrode 1038 by repeatedly applying electric pulses that rise quickly. A streamer discharge is generated at 1038.

  The reason why the upper surface 1904 of the workpiece 1902 is processed by generating the streamer discharge is mainly that the pulse electric field, nitrogen radicals, and short-wavelength ultraviolet rays act on the upper surface 1904 of the workpiece 1902 in a composite manner. Depending on the state of the streamer discharge, etc., only one or two of the three elements of the pulsed electric field, nitrogen radical, and short wavelength ultraviolet light may be dominant in the process.

(Action of nitrogen radical)
When streamer discharge is generated in the gap 1038, plasma containing nitrogen radicals with extremely high activity is generated in the gap 1038. Therefore, when streamer discharge is generated, nitrogen radicals chemically act on the surface layer 1912 and the surface layer 1912 is processed.

The reason why nitrogen radicals are selected as the chemical species used for processing, that is, the reason why plasma is generated in a processing gas containing nitrogen gas as a main component is that the activity of nitrogen radicals is extremely high. This is clear from the fact that the dissociation energy of the nitrogen molecule is very high at 9.76 eV. The lifetime of the triplet nitrogen ( ³ Σ _u ) radical reaches 10 milliseconds, which contributes to efficient reforming.

  In addition, the fact that nitrogen gas can be easily obtained at a low price and is easy to handle is one of the reasons for selecting nitrogen radicals as the active species used in the treatment.

(Action of short wavelength ultraviolet rays)
When streamer discharge is generated in the gap 1038, the processing gas emits short wavelength ultraviolet rays due to streamer discharge. Therefore, when streamer discharge is generated, short wavelength ultraviolet rays are photochemically acted on the surface layer 1912 and the surface layer 1912 is processed.

  “Short wavelength ultraviolet rays” are ultraviolet rays mainly containing a wavelength component of 100 to 280 nm, and are also called “far infrared rays” or “UV-C”. The reason why short-wavelength ultraviolet rays are applied is that short-wavelength ultraviolet rays do not penetrate deep into the workpiece 1902, so that they are concentrated only on the extremely thin surface layer 1912 to give a photochemical action.

(Streamer discharge)
FIG. 11 shows streamer discharge generated in the gap 1038 when an electric pulse is applied between the first electrode 1012 and the second electrode 1046 using the first electrode 1012 as a cathode and the second electrode 1046 as an anode. It is a schematic diagram which shows a state. The electric pulse for generating the streamer discharge has a peak voltage of approximately 10 to 100 kV, a full width at half maximum (FWHM) of approximately 100 to 50000 ns, and a time rise rate dV / dt of the rising voltage of approximately 1 to 500 kV / It is an electric pulse with μs and a frequency of approximately 1 to 50 kHz. The electric pulse is a unipolar electric pulse whose polarity does not change, but may be a bipolar electric pulse whose polarity changes alternately.

  When the streamer discharge is generated in the gap 1038, as shown in FIG. 11, the streamer 1930 is directed from the second electrode structure 1036 to the first electrode structure 1004 but does not reach the first electrode structure 1004. And light purple light emission that spreads from the lower surface of the second electrode structure 1036 toward the upper surface of the first electrode structure 1004 is observed. “The streamer 1930 does not reach the first electrode structure 1004” means that the application of the electric pulse is stopped before the occurrence of the arc discharge.

  It is also desirable to stop applying the electric pulse before the long branched streamer 1930 as shown in FIG. 12 grows. That is, an electric pulse having a full width at half maximum FWHM of 100 to 50000 ns is applied between the first electrode 1012 and the second electrode 1046, and streamer discharge in which short streamers 196 are scattered as shown in FIG. It is also desirable to generate it. The fine streamer discharge in which the application of the electric pulse is stopped in the initial stage of the streamer growth is excellent in the uniformity of the discharge. Therefore, when the fine streamer discharge is generated, the processing region 1910 of the work 1902 is uniformly processed. Thus, local damage of the workpiece 1902 due to non-uniform discharge is suppressed.

  In the above description, the range of the half-value width or the like is “substantially” because the structure and material of the first electrode structure 1004 and the second electrode structure 1036, the interval of the gap 1038, the pressure of the processing gas, etc. This is because, depending on the specific configuration of the processing apparatus 1002, a range such as a half width at which streamer discharge occurs may be wider than the above range. Therefore, it is desirable to determine whether or not the discharge is a streamer discharge by observing the actual discharge.

(2. Second Embodiment)
The second embodiment relates to an output adjustment mechanism 2300 that is desirably added to the plasma processing apparatus 1002 of the first embodiment. In the output adjustment mechanism 2300 of the second embodiment, the output PW of the pulse power source 1010 increases as the facing area S between the first facing surface 1020 of the first electrode 1012 and the second facing surface 1050 of the second electrode 1048 increases. Increase. Accordingly, when the second electrode structure 1036 scans the upper surface 1904 of the work 1902, the first opposing surface 1020 of the first electrode 1012 and the second opposing surface 1050 of the second electrode 1048 are opposed to each other. The fluctuation of the output PW / S of the pulse power supply 1010 per unit area of the area to be reduced is reduced, and the processing target area 1910 of the work 1902 is processed uniformly.

  FIG. 13 is a block diagram of the output adjustment mechanism 2300 of the second embodiment.

  As shown in FIG. 13, the output adjustment mechanism 2300 includes a relative position detector 2302 that detects the relative position PS of the second electrode structure 1036 with respect to the first electrode structure 1004, the relative position PS, and the facing area S. A storage device 2304 that stores information for specifying the relationship between the two, and a control unit 2306 that controls the output PW of the pulse power supply 1010.

  The relative position detector 2302 detects the relative position PS by measuring the position of the first electrode structure 1004 itself or the carrier on which the first electrode structure 1004 is mounted with an encoder, a potentiometer, or the like. Of course, when the second electrode structure 1036 is transported, the relative position detector 2302 measures the position of the second electrode structure 1036. The relative position PS may be detected by counting the driving pulses applied to the stepping motor using the power source of the transport mechanism 1006 as a stepping motor. The relative position PS may be detected by measuring an elapsed time after the transport mechanism 1006 starts transport.

  The storage device 2304 is a semiconductor memory, a disk drive, or the like. Information for specifying the relationship between the relative position PS and the facing area S is stored in advance in the storage device 2304 as a table describing the correspondence between the relative position PS and the facing area S, for example.

  The control unit 2306 acquires the detection result of the relative position detector 2302 and reads information specifying the relationship between the relative position PS and the facing area S from the storage device 2304, and the output PW of the pulse power source 1010 increases as the facing area S increases. The pulse power supply 1010 is controlled to increase. When the IES power supply 1100 is used as the pulse power supply 1010, the amount of energy stored in the step-up transformer 1106 is adjusted by adjusting the length of the ON signal that the gate drive circuit 1112 gives to the MOSFET 1110. The output is adjusted.

  The function of the control unit 2306 is realized by causing an embedded computer to execute a control program. Part or all of the functions may be realized by dedicated hardware.

(3. Third embodiment)
The third embodiment relates to an output adjustment mechanism 3300 that is employed instead of the output adjustment mechanism 2300 of the second embodiment.

  FIG. 14 is a block diagram of an output adjustment mechanism 3300 according to the third embodiment.

  As shown in FIG. 14, the output adjustment mechanism 3300 includes a peak voltage detector 3310 that detects a peak voltage of an electric pulse and a control unit 3312 that controls an output PW of the pulse power supply 1010.

  The input of the peak voltage detector 3310 is connected to the first electrode 1012 and the second electrode 1046, and a signal corresponding to the peak voltage of the electric pulse is output from the output of the peak voltage detector 3310. The peak voltage detector 3310 detects the peak voltage of the electric pulse applied between the first electrode 1012 and the second electrode 1046.

  FIG. 15 is a circuit diagram of a peak hold circuit 3314 employed as the peak voltage detector 3310.

  In the peak hold circuit 3314, one end of a parallel connection body of a voltage holding capacitor 3316 and a discharge resistor 3318 is connected to one end of an input 3324 via a backflow prevention diode 3320, and the other end of the parallel connection body. Is connected to the other end of the input 3324. In addition, one end of the parallel connection body is connected to one end of the output 3326, and the other end of the parallel connection body is connected to the other end of the output 3326. The anode of the diode 3320 is connected to one end of the input 3324, and the cathode of the diode 3320 is connected to one end of the parallel connection body. The capacitance value of the capacitor 3315 and the resistance value of the resistor 3318 are determined such that the time constant of the parallel connection body is several times to several hundred times the period of the electric pulse. Instead of the peak hold circuit 3314 shown in FIG. 15, a more complicated peak hold circuit including an operational amplifier or the like is also employed.

  The control unit 3312 acquires the detection result of the peak voltage detector 3310 and controls the pulse power supply 1010 so that the output PW of the pulse power supply 1010 increases as the facing area S increases. The control unit 2306 detects the peak voltage by utilizing the fact that the capacitance between the first electrode 1012 and the second electrode 1046 increases and the peak voltage of the electric pulse decreases as the facing area S increases. The output PW of the pulse power source 1010 increases as the peak voltage detected by the device 3310 decreases. When the IES power source 1100 is used as the pulse power source 1010, the amount of energy stored in the step-up transformer 1106 is adjusted by adjusting the length of the ON signal that the gate drive circuit 1112 gives to the MOSFET 1110. The output PW is adjusted.

  FIG. 16 is a circuit diagram of a voltage comparison circuit 3328 employed as the control unit 3312. In the voltage comparison circuit 3328, the non-inverting input of the comparator 3330 is connected to one end of the input 3332, and the inverting input is connected to the other end of the input 3332 and the other end of the output 3336 via the constant voltage source 3334. The output of the comparator 3330 is connected to one end of the output 3336.

  Accordingly, the control unit 3312 outputs a positive signal when the peak voltage falls below the voltage of the constant voltage source 3334, and outputs a negative signal when the peak voltage falls below the voltage of the constant voltage source 3334. The gate drive circuit 1112 increases the length of the ON signal supplied to the MOSFET 1110 so that the output PW of the pulse power supply 1010 increases when a negative signal is input, compared to when a positive signal is input.

  Note that the number of comparators may be increased to two or more, and the output PW of the pulse power supply 1010 may be switched in multiple stages. Further, the output of the peak voltage detector 3310 may be converted into a digital signal by an A / D converter and then applied to an embedded computer that executes a control program, and more detailed control may be performed.

(4. Fourth embodiment)
The fourth embodiment relates to an output adjustment mechanism 4300 employed in place of the output adjustment mechanism 2300 of the second embodiment.

  FIG. 17 is a block diagram of an output adjustment mechanism 4300 according to the fourth embodiment.

  As shown in FIG. 17, the output adjustment mechanism 4300 includes a photodetector 4342 that detects plasma light emitted from a gap 1038 between the first electrode structure 1004 and the second electrode structure 1036, and a pulse power supply 1010. And a control unit 4344 for controlling the output PW.

  The detection portion of the photodetector 4342 is directed to the gap 1038 between the first electrode structure 1004 and the second electrode structure 1038, and the gap between the first electrode structure 1004 and the second electrode structure 1036. The plasma light emitted from 1038 is received and a signal corresponding to the plasma light is output.

  The photodetector 4342 arranges a plurality of photosensors in the extending direction of the second facing surface 1050 of the second electrode 1046, and the plasma light emitted from each position in the extending direction is a plurality of photosensors. Each is configured to be detected. Thereby, not only the intensity of the plasma light but also the spread of the plasma light in the extending direction is detected. Photosensors include photoelectric conversion elements such as photodiodes and photomultipliers, and light-dependent resistance elements such as cadmium sulfide cells.

  In order to improve the efficiency of detection of plasma light by the photodetector 4342, it is also desirable to add an optical system for condensing the plasma light.

  The control unit 4344 acquires the detection result of the photodetector 4342 and controls the pulse power supply 1010 so that the output PW of the pulse power supply 1010 increases as the facing area S increases. The control unit 4344 uses the fact that the intensity of the plasma light is increased and the spread of the plasma light is increased as the facing area S is increased, and the output of the pulse power source 1010 is increased as the intensity of the plasma light is increased. As the spread becomes wider, the output of the pulse power supply 1010 is increased. When the IES power supply 1100 is used as the pulse power supply 1010, the amount of energy stored in the step-up transformer 1106 is adjusted by adjusting the length of the ON signal that the gate drive circuit 1112 gives to the MOSFET 1110. The output is adjusted.

  The function of the control unit 4344 is realized by causing an embedded computer to execute a control program. Part or all of the functions may be realized by dedicated hardware.

(5. Fifth embodiment)
The fifth embodiment relates to a second electrode structure 5036 employed in place of the second electrode structure 1036 of the first embodiment.

  FIG. 18 is a schematic diagram of the second electrode structure 5036 of the fifth embodiment. FIG. 18 is a perspective view of the second electrode structure 5036.

  As shown in FIG. 18, instead of the second electrode structure 1036 covering the second electrode 1046 having a plate shape with a second dielectric barrier 1048 having a sheath shape, it has a round bar shape or a round pipe shape. A second electrode structure 5036 that covers the second electrode 5046 with a second dielectric barrier 5048 having a round pipe shape may be employed. Also in the second electrode structure 5036, the second facing surface (lower half of the cylindrical outer surface) 5050 of the second electrode 5046 extends in a direction parallel to the first facing surface 1020 of the first electrode 1012. As a result of the existing linear elongated surface, the facing area between the first facing surface 1020 of the first electrode 1012 and the second facing surface 5050 of the second electrode 5046 is reduced, so that the discharge uniformity And the processed area 1908 of the workpiece 1902 is processed uniformly.

(6. Sixth embodiment)
The sixth embodiment relates to a first electrode structure 6004 employed in place of the first electrode structure 1004 of the first embodiment.

  FIG. 19 is a schematic diagram of the first electrode structure 6004 of the sixth embodiment. FIG. 19 is a perspective view of the first electrode structure 6004.

  As shown in FIG. 19, the first electrode structure 6004 of the sixth embodiment has a structure in which a protrusion 6006 is added to the support surface of the first electrode structure 1004 of the first embodiment. The protrusion 6006 is formed at a position where the end surface of the workpiece 1902 hits when the planar position of the first facing surface 6020 of the first electrode 6012 and the planar position of the processing target region 1908 of the workpiece 1902 are matched. Thereby, positioning of the workpiece 1902 is facilitated.

(7. Seventh embodiment)
The seventh embodiment relates to a first electrode structure 7004 employed in place of the first electrode structure 1004 of the first embodiment.

  FIG. 20 is a schematic diagram of the first electrode structure 7004 of the seventh embodiment. FIG. 20 is a perspective view of the first electrode structure 7004.

  As shown in FIG. 20, the first electrode structure 7004 of the seventh embodiment has a structure in which an accommodation groove 7008 for accommodating a work 1902 is formed on the support surface of the first electrode structure 1004 of the first embodiment. Have. The planar shape of the accommodation groove 7008 is substantially the same as the planar shape of the workpiece 1902. The position where the accommodation groove 7008 is formed is that the planar position of the first facing surface 7020 of the first electrode 7012 and the planar position of the processing target area 1908 of the workpiece 1902 when the workpiece 1902 is accommodated in the accommodation groove 7008. It is a good position. It is desirable that the end of the receiving groove on the opening side is trimmed. Thereby, even if the position where the workpiece 1902 is placed is slightly shifted, the workpiece 1902 is accommodated in the accommodation groove 7004.

(8. Others)
Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited to the above description. Innumerable variations not illustrated may be envisaged without departing from the scope of the present invention. In particular, it is naturally planned to combine the items described in each embodiment.

DESCRIPTION OF SYMBOLS 1002 Plasma processing apparatus 1004 1st electrode structure 1010 Pulse power supply 1012 1st electrode 1020 1st opposing surface 1006 Transfer mechanism 1036 2nd electrode structure 1050 2nd opposing surface 1040 Processing gas supply body

Claims (8)

A plasma processing apparatus,
A first electrode structure having a first electrode having a first opposing surface having a planar shape corresponding to a planar shape of a region to be treated on the surface of the workpiece, and having a support surface for supporting the workpiece;
A second electrode structure comprising a second electrode having a linear second opposing surface;
A power source having one output terminal connected to the first electrode and the other output terminal connected to the second electrode;
The first electrode structure with respect to the first electrode structure in a direction different from a direction in which the second facing surface extends via a facing position where the first facing surface and the second facing surface face each other. A transport mechanism for relatively moving the second electrode structure;
A processing gas is supplied to the gap between the first electrode structure and the second electrode structure when the relative position of the second electrode structure with respect to the first electrode structure is in the facing position. A processing gas supply mechanism;
A plasma processing apparatus comprising: The plasma processing apparatus according to claim 1.
An output adjustment mechanism that increases the output of the power source as the facing area between the first facing surface and the second facing surface increases;
A plasma processing apparatus further comprising: The plasma processing apparatus according to claim 2, wherein
The output adjustment mechanism is
A relative position detector for detecting a relative position of the second electrode structure with respect to the first electrode structure;
A storage device for storing information for specifying a relationship between a relative position of the second electrode structure with respect to the first electrode structure and a facing area between the first facing surface and the second facing surface;
A control unit that acquires a detection result of the relative position detector, reads information specifying a relationship between a relative position and a facing area from the storage device, and controls an output of the power source;
A plasma processing apparatus comprising: The plasma processing apparatus according to claim 2, wherein
The power source is a pulse power source;
The output adjustment mechanism is
A peak voltage detector for detecting a peak voltage of an electric pulse applied between the first electrode and the second electrode;
A controller for obtaining a detection result of the peak voltage detector and controlling an output of the power source;
A plasma processing apparatus comprising: The plasma processing apparatus according to claim 2, wherein
The output adjustment mechanism is
A photodetector for detecting plasma light emitted from the gap;
A control unit for obtaining a detection result of the photodetector and controlling an output of the power source;
A plasma processing apparatus comprising: The plasma processing apparatus according to claim 5, wherein
The photodetector detects the intensity and spread of the plasma light;
The control unit increases the output of the power source as the intensity of the plasma light increases, and increases the output of the power source as the spread of the plasma light increases.
Plasma processing equipment. The plasma processing apparatus according to claim 1.
The power source is a pulse power source;
Plasma processing equipment. The plasma processing apparatus according to claim 7, wherein
The pulse power source is an inductive energy storage type,
Plasma processing equipment.

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