JP2009231247A - Plasma treatment device, and supplying method of high frequency power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supplying method of a high frequency power in which, when a membrane mobility is increased and a high frequency power is impressed on a susceptor, an occurrence of an induction magnetic field is canceled. <P>SOLUTION: The microwave plasma treatment device 10 includes a treatment vessel 100, a susceptor 105 which is housed in the treatment vessel and on which a substrate G is mounted, three power supply cables B1-B3 which contact with the susceptor on three positions P1-P3 provided on a same circumference of the susceptor 105, and a high frequency power source 130 which is connected with the three power supply cables B1-B3 and supplies a high frequency power to the susceptor 105 from the positions P1-P3 of three or more through the three power supply cables B1-B3. The three power supply cables B1-B3 are made to contact with the susceptor 105 on the three positions P on the same circumference of the susceptor 105. The high frequency power source 130 is connected with the three power supply cables B1-B3 and the high frequency power output from the high frequency power source 130 is supplied to the susceptor 105 from the three positions P1-P3 through the three power supply cables B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that plasmas an object to be processed using plasma generated by exciting a gas, and more specifically, a method of supplying high-frequency power to a susceptor provided in the plasma processing apparatus. About.

  In a plasma processing apparatus, a gas is excited to generate plasma, and a plasma process such as etching or film formation is performed on an object to be processed using the generated plasma. As an energy source for generating a plasma by exciting a gas, a microwave source, a high-frequency power source, a magnetron, and the like are known.

  In addition to such an energy source, a plasma processing apparatus is generally provided with a separate high frequency power source as an energy source for applying a predetermined bias voltage to a susceptor (mounting table) (for example, a patent) Reference 1). A predetermined bias voltage is applied to the susceptor by the high-frequency power output from the high-frequency power source, and ions contained in the plasma are attracted toward the susceptor by this energy. Thus, by applying the high frequency power output from the high frequency power source to the susceptor, the energy when the electric charge collides with the object to be processed can be increased.

There are two possible methods for supplying high-frequency power into the susceptor. One of them is that a metal electrode covered with an insulator such as alumina (Al ₂ O ₃ ) is disposed on a base material such as aluminum, and a power supply line connected to a high-frequency power source is connected to the metal electrode, In this method, high-frequency power is applied from a high-frequency power supply via a feeder line. The other is to electrically connect the substrate and the power supply line by embedding the power supply line in the base material itself such as aluminum covered with an insulator, and apply high frequency power from the high frequency power source via the power supply line. Is the method.

JP 2000-173993 A

  However, in any method, when high-frequency power is applied from the power supply line to the susceptor, if a current flows through the power supply line, the right-handed screw law causes the dielectric wire B to move around as shown in FIG. An induction magnetic field Ma is generated. At this time, since there is one feeder line, the induced magnetic field generated is not weakened or canceled. Since plasma is composed of charged particles such as electrons and ions and radicals, the induced magnetic field generated in this way may disturb the behavior of the charged particles in the plasma and may make the control of the plasma unstable. .

  Further, there is only one power supply point between the power supply line and the susceptor, and the contact area is small. Therefore, when high-frequency high-frequency power is supplied to the susceptor, a large load is applied to the contact portion (feed point) between the feeder line and the susceptor, and the contact portion may be damaged by heat or the like. Further, since the high frequency power is propagated through one power supply line, the loss of the high frequency power is increased by the resistance of the power supply line as compared with the case where the high frequency power is applied in parallel from a plurality of lines.

  In order to solve the above problems, the present invention provides a plasma processing apparatus that reduces the generation of an induction magnetic field when high-frequency power is applied to a susceptor.

  That is, in order to solve the above-described problem, according to an aspect of the present invention, there is provided a plasma processing apparatus that plasma-processes an object to be processed using plasma generated by exciting a gas, a processing container, Electrically connected to the susceptor at the power supply point so that three or more power supply points are positioned on the same circumference of the susceptor provided inside the processing container and on which the object to be processed is placed Three or more feeders that are connected, and a high-frequency power source that is connected to the three or more feeders and that supplies the high-frequency power from the three or more feeder points to the susceptor via the three or more feeders; Is provided.

  According to this, high frequency power is supplied to the susceptor from three or more feeding points provided on the same circumference via three or more feeding lines. One example will be described with reference to FIG. In FIG. 3, three power supply lines B1 to B3 are electrically connected to the susceptor 105 at three power supply points P1 to P3. As a result, high frequency power is supplied to the susceptor from the respective feeding points P1, P2, P3 on the same circumference with respect to the center point O.

  When current flows from the back side to the front of each paper feed line B1, B2, B3 with each feed point P1, P2, P3 as its end, each feed line B1, B2, B3 Induced magnetic fields m1, m2, and m3 are generated around the counterclockwise direction according to the right-handed screw law. Since each induction magnetic field m1, m2, m3 is generated from a position on the same circumference, the induction magnetic fields Ma1, Mb interfere with each other evenly in a spiral shape, and the opposite induction magnetic fields Ma, Mb are formed as a whole. The two induction magnetic fields Ma and Mb cancel each other. In this way, when high frequency power is supplied from three or more feeders to the susceptor, the induction magnetic field generated on the outer periphery of the feeder can be canceled. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  Three or more feeders may be electrically connected to the susceptor such that three or more feeder points are positioned on each circumference of one or more circles having the same center point. For example, as shown in FIG. 9B, there are feeding points P1 to P6 and positions P7 to P10 on the circumferences of concentric circles S and T having the same center point O. According to this, the dielectric magnetic field generated from the six feeding points located on the circumference of the circle S is canceled by the principle shown in FIG. Also, the dielectric magnetic field generated from the four feeding points located on the circumference of the circle T is canceled by the same principle.

  In this way, by positioning three or more feeding points in each circle on the concentric circle, the magnetic field generated from each feeding point is canceled for each circle. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  Three or more feeders may be electrically connected to the susceptor such that three or more feeder points are positioned on each circumference of one or more circles having different center points. For example, as shown in FIG. 9A, when feeding points P1 to P4 and positions P5 to P8 are provided on the circumferences of two different circles S and T having different center points O1 and O2, respectively. It is. According to this, the dielectric magnetic fields generated from the feed points located four each on the circumferences of the circles S and T are canceled for each circle.

  In this way, by positioning three or more feeding points in each circle on a plurality of different circles, the magnetic field generated from each feeding point is canceled for each circle. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  In addition, a heater embedded in the susceptor may be provided, and the three or more power supply lines may be connected to the heater in the susceptor at three or more power supply points provided on the same circumference of the heater. . At this time, the three or more feeders may be connected to the sheath tube 120b of the heater.

  In particular, the sheath tube 120b of the heater can be used as an electrode by bringing three or more power supply lines into contact with the heater at three or more power supply points provided on the same circumference of the heater. Since the surface area of the sheath tube is large, the current flowing per unit area can be reduced to reduce the loss of high-frequency power.

  In addition, since the entire sheath tube becomes a contact portion when supplying high-frequency power to the susceptor, the load on the contact portion can be reduced. As a result, higher power high frequency power can be input to the susceptor. Further, by using the sheath tube as an electrode, it is not necessary to provide an electrode other than the heater in the susceptor, and the cost can be reduced.

  Of course, even when the sheath tube is used as an electrode, as described above, by connecting three or more feeders to the heater at three or more feeder points provided on the same circumference of the sheath tube, When supplying high-frequency power from the power supply line into the susceptor, the induced magnetic field generated on the outer periphery of the power supply line can be canceled. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  The three or more feeders may be formed in a rod shape. The three or more feeders may be arranged in parallel to each other. With this configuration, when a current flows in the same direction from the high-frequency power source through three or more feeders, the dielectric magnetic field generated in response to the current can be reliably canceled as a whole.

  Three or more feeders may be connected to a plurality of high-frequency power sources or connected in parallel to a single high-frequency power source. That is, the power supply line and the high-frequency power source may be connected in a one-to-one relationship, or may be connected in a many-to-one relationship. In any case, by supplying high frequency power to the susceptor from three or more power supply points via three or more power supply lines, the induced magnetic field generated from each power supply point can be canceled, and the plasma is disturbed by the induced magnetic field. Can be avoided.

  A matching unit that is provided between the high-frequency power source and the three or more feeders and that matches an output impedance of the high-frequency power source and a load impedance on a plasma side; You may have the variable capacitor and inductor provided in the main power supply line which connects the said 3 or more feeders, and the variable capacitor provided in each feeder of the said 3 or more feeders.

  According to this, the output capacitor on the high frequency power supply side and the load impedance on the plasma side are matched by the variable capacitor and inductor provided in the main power supply line, and fine adjustment is performed by the variable capacitor provided in each power supply line. be able to. As a result, by supplying high frequency power uniformly to the susceptor, the plasma can be controlled with high accuracy and the process can be performed more stably.

  As shown in FIG. 11, the susceptor is symmetrically divided into a plurality of parts, and among the divided susceptors, the same circumference within the same susceptor or across a plurality of susceptors. At least one of the three or more power supply lines may be connected to any of the plurality of divided susceptors so that three or more power supply points are positioned on the top.

  Further, as shown in FIG. 13, heaters are embedded in the plurality of divided susceptors, respectively, and each of the plurality of divided susceptors has the three or more tubes using the sheath tube as a feeding point. At least one of the feeder lines may be connected.

  The plasma processing apparatus may be a microwave plasma processing apparatus, an inductively coupled plasma processing apparatus, a capacitively coupled plasma processing apparatus, an electron cyclotron resonance plasma processing apparatus, or a dipole ring magnetron plasma processing apparatus.

  In order to solve the above-described problems, according to another aspect of the present invention, there is provided a method of supplying high-frequency power to a plasma processing apparatus that performs plasma processing on an object to be processed using plasma generated by exciting a gas. Then, three or more feeders are electrically connected to the susceptor at the feeding point so that three or more feeding points are positioned on the same circumference of the susceptor on which the workpiece is placed, and the 3 High-frequency power is output from a high-frequency power source connected to at least two power supply lines, and the high-frequency power is supplied to the susceptor from three or more power supply points positioned on the same circumference via the three or more power supply lines. A method of providing is provided.

  According to this, high frequency power is supplied to the susceptor from three or more feeding points provided on the same circumference via three or more feeding lines. Since the induction magnetic field generated from each feeding point is generated from each position on the same circumference, it interferes with each other evenly in a spiral shape, and as a whole, an induction magnetic field that is counterclockwise and a clockwise induction magnetic field are generated. Form. These two induced magnetic fields cancel each other. In this way, when high-frequency power is supplied from the power supply line to the susceptor, the induction magnetic field generated on the outer periphery of the power supply line is canceled to prevent the plasma from being disturbed by the induction magnetic field, thereby stably controlling the plasma. be able to.

  As described above, according to the present invention, when high frequency power is applied to the susceptor, generation of an induction magnetic field can be reduced.

BEST MODE FOR CARRYING OUT THE INVENTION

(First embodiment)
First, a plasma processing apparatus according to a first embodiment of the present invention will be described with reference to FIG. In the present embodiment, a microwave plasma processing apparatus will be described as an example of the plasma processing apparatus. Note that, in the following description and the accompanying drawings, the same reference numerals are given to components having the same configuration and function, and redundant description is omitted.

  In the first embodiment, as a plasma processing apparatus that excites a gas by microwave electric field energy and finely processes a substrate using plasma generated thereby, a CMEP (Cellular Microwave Excitation Plasma) plasma processing apparatus (microwave) is used. A plasma processing apparatus 10) is used.

  The microwave plasma processing apparatus 10 includes a processing container 100 and a lid 200. The processing container 100 has a bottomed cubic shape with an upper portion opened. An O-ring 300 is disposed on the contact surface between the processing container 100 and the lid 200. As a result, the processing vessel 100 is sealed, and a processing chamber U in which plasma processing is performed is defined. The processing container 100 and the lid 200 are made of, for example, a metal such as aluminum and are electrically grounded.

  At the bottom of the processing container 100, a susceptor (mounting table) 105 on which the substrate G is placed is installed via an insulator 110, whereby the susceptor 105 and the processing container 100 are electrically insulated. The susceptor 105 is made of, for example, aluminum nitride, and a power feeding unit 115 (corresponding to a power feeding point) and a heater 120 are provided therein.

  A high frequency power source (RF) 130 is connected to the power supply unit 115 via a matching unit 125, and a predetermined bias voltage is applied to the inside of the processing container 100 by the high frequency power output from the high frequency power source 130. ing. The high frequency power supply 130 is provided outside the processing container 100 and is grounded.

  For example, as illustrated in FIG. 7, the heater 120 is stretched around the susceptor 105 in a pattern of a plurality of heaters. An AC power source 145 is connected to each heater 120 via the filter 135 and the SSR 140 shown in FIG. The AC power source 145 is provided outside the processing container 100 and is grounded.

  A baffle plate 150 is provided around the susceptor 105 to control the gas in the processing chamber U to a preferable flow. A vacuum pump (not shown) provided outside the processing container 100 is provided at the bottom of the processing container 100. The vacuum pump discharges the gas in the processing container 100 through the gas discharge pipe 155 to reduce the pressure in the processing chamber U to a desired degree of vacuum.

The lid 200 is provided with six rectangular waveguides 205, a slot antenna 210, and a plurality of dielectric plates 215. The six rectangular waveguides 205 have a rectangular cross-sectional shape, and are arranged at equal intervals in the lid 200. Each rectangular waveguide 205 is filled with a dielectric member 205a such as fluororesin (for example, Teflon (registered trademark)), alumina (Al ₂ O ₃ ), quartz or the like, and λg ₁ = The in-tube wavelength λg ₁ of the microwave propagating through each rectangular waveguide 205 is controlled according to the equation of λc / (ε ₁ ) ^1/2 . Here, λc is the wavelength of the microwave propagating in free space, and ε ₁ is the relative dielectric constant of the dielectric member 205a. Each rectangular waveguide 205 is connected to a microwave source (not shown).

The slot antenna 210 is a metal such as aluminum and is formed of a nonmagnetic material. In the slot antenna 210, slots 210 a (openings) are opened at equal intervals on the lower surface of each rectangular waveguide 205. Each slot 210a is filled with a dielectric member 210a1 such as fluororesin, alumina (Al ₂ O ₃ ), quartz, etc., and λg ₂ = λc / (ε ₂ ) ^1/2 by the dielectric member 210a1. The guide wavelength λg ₂ of the microwave propagating in each slot 210a is controlled according to the equation. Here, ε ₂ is a relative dielectric constant of the dielectric member 210a1 inside the slot 210a.

  Each dielectric plate 215 is formed in a tile shape, and is attached so as to be positioned on the lower surface of the slot 210a while being supported by the grid-like metal beam 220. Thus, a large number of dielectric plates 215 are arranged in an array at an equal pitch over the entire ceiling surface. A gas introduction pipe 225 passes through the metal beam 220.

Each dielectric plate 215 is formed using a dielectric material such as quartz glass, AlN, Al ₂ O ₃ , sapphire, SiN, or ceramics. Irregularities are formed on the surface of each dielectric plate 215 facing the substrate G. Thereby, the intensity | strength of the electric field energy of the microwave supplied from each dielectric material board 215 can be made more uniform.

  A cooling water supply source 405 is connected to the cooling water pipe 400, and the cooling water supplied from the cooling water supply source 405 circulates in the cooling water pipe 400 and returns to the cooling water supply source 405. The body 200 is maintained at a desired temperature.

  The gas supply source 500 communicates with the gas introduction pipe 225 via the gas line 505. By controlling the opening / closing of each valve and the opening (not shown) of each mass flow controller, a gas having a desired concentration is supplied into the processing vessel 100 from the gas line 505 and the gas introduction pipe 225.

  With the configuration described above, for example, 2.45 GHz microwaves output from the microwave source propagate through each rectangular waveguide 205 and pass through each dielectric plate 215 in the same direction through each slot 210a. And it radiates | emits in the process chamber U from the lower surface of each dielectric plate. The microwaves radiated into the processing chamber U excite the gas introduced in the vicinity of each dielectric plate 215 from the gas introduction tube 225, thereby generating plasma below the ceiling surface. The substrate G is subjected to plasma processing such as etching and film formation by the action of the generated plasma.

(Power supply circuit Cir connected to the susceptor)
Next, the power circuit Cir connected to the susceptor shown in FIG. 1 will be described with reference to FIG. As described above, the matching unit 125 is provided between the power supply unit 115 and the high-frequency power source 130. The three power supply lines B1, B2, and B3 connect the power supply units 115a, 115b, and 115c to the matching unit 125, respectively. The high frequency power supply 130 and the matching unit 125 are connected by a main power supply line 130a.

  The matching unit 125 includes variable capacitors C1, C2, and C3 connected in series to the respective power supply lines B1, B2, and B3, a variable capacitor CC that is connected between the main power supply line 130a and the ground line 130b, and an inductor. L is comprised.

  The matching unit 125 functions to make the output impedance of the high-frequency power supply 130 and the load impedance obtained by combining the load of the matching unit 125 and the load inside the processing container 100 seem to coincide. Specifically, the variable capacitor CC and the inductor L match the output impedance of the high-frequency power supply 130 and the load impedance on the plasma side, and the variable capacitors C1, C2, C3 connected to the power supply lines B1, B2, B3, respectively. Is used to cancel the reflection of the high-frequency power from each of the power feeding units 115a, 115b, and 115c. As a result, the high frequency power supply 130 can be protected and the high frequency power output from the high frequency power supply 130 can be supplied uniformly. As a result, the plasma can be accurately controlled and the process can be performed more stably.

  An AC power supply 145 is connected to the heater 120 via an RF filter 135, a transformer Tr, and an SSR 140 (Solid State Relay). The filter 135 removes the high frequency output from the high frequency power source 130 and protects the AC power source 145. The transformer Tr insulates common mode noise of the high frequency power supply 130. The SSR 140 controls the heater power. Thereby, the heater 120 is configured to hold the substrate G at a predetermined temperature by the AC voltage output from the AC power source 145.

(No magnetic field)
Next, a mechanism for canceling the induced magnetic field in the microwave plasma processing apparatus 10 according to the present embodiment will be described in comparison with a general microwave plasma processing apparatus shown in FIG. FIG. 16B shows an induced magnetic field when a cross section of the susceptor 105 taken along the cutting line ZZ in FIG. 16A is viewed from the upper part of the susceptor. In the following description, the case where the cross section of the susceptor 105 is viewed from above the susceptor will be described.

  In FIG. 16B, a current flows through the feeder line B from the back side to the near side. In this case, an induction magnetic field Ma is generated on the outer periphery of the feeder line B in the counterclockwise direction by the right-handed screw law. The generated induced magnetic field may disturb the plasma state.

  As described above, in the microwave plasma processing apparatus 10 according to the present embodiment, high-frequency power is supplied to the susceptor (power supply unit 115) using the three power supply lines B1, B2, and B3. At this time, how the induced magnetic field is canceled will be described with reference to FIG. FIG. 3 is a view of the AA cross section shown in FIG. 1 as viewed from above the susceptor. A current flows through the feeder lines B1 to B3 from the back side to the near side.

  In the power feeding unit 115, three power feeding lines B 1, B 2, B 3 are connected to the susceptor 105 at power feeding points P 1, P 2, P 3 on the same circumference C with respect to the center point O. In this case, induced magnetic fields m1, m2, and m3 are generated in the respective feed lines B1, B2, and B3 counterclockwise by the right-handed screw law. Since each induction magnetic field m1, m2, m3 is generated from each feeding point P1, P2, and P3 on the same circumference, they interfere with each other evenly in a spiral shape, and as a whole, the induction magnetic field Ma opposite to the clock is Ma. And a clockwise induction magnetic field Mb are formed. The two induction magnetic fields Ma and Mb cancel each other.

  Thus, in the microwave plasma processing apparatus 10 according to the present embodiment, when high frequency power is supplied from the power supply line to the susceptor, the plasma is generated by the induction magnetic field by canceling the induction magnetic field generated on the outer periphery of the power supply line. Disturbance can be prevented and plasma can be controlled stably.

  In the power feeding unit 115, it is necessary that three or more power supply lines B are electrically connected to the susceptor 105 at three or more power supply points P provided on the same circumference. The reason why “three or more feeding points P provided on the same circumference” is set to two feeding points is similar to the case where the induction magnetic field cannot be canceled by one feeding line B as described above. This is because the induced magnetic field cannot be canceled even if an electric wire is used.

  As shown in FIG. 4 (a), the induction magnetic fields m1 and m2 are generated from the feed points P1 and P2 on the same circumference, so that they interfere with each other evenly and the feed lines B1 and B2 Although they cancel each other out, the induced magnetic field Ma generated outside the feeder lines B1 and B2 is not canceled and remains. Thus, when there are two power supply lines, the induced magnetic field cannot be canceled, and there is a possibility that the plasma may be disturbed by the induced magnetic field.

  In addition, even if three or more feeders are connected to the susceptor at three or more feeders provided on one circumference, if one or two other feeders are used, the induced magnetic field is It cannot be canceled. As shown in FIG. 4 (b), the induction magnetic fields m1 to m4 are generated from the feed points P1 to P4 on the same circumference, so that they interfere with each other evenly and the feed lines B1 to B4 The outer induction magnetic field Ma and the inner induction magnetic field Mb are formed and canceled. However, the induction magnetic field m5 generated by passing a current through the feeder line B5 remains as it is. Thus, “three or more feeding points P provided on the same circumference” means that when there are a plurality of circles, three or more feeding points are required for each circle. .

(Second Embodiment)
Next, a microwave plasma processing apparatus 10 according to the second embodiment will be described with reference to FIG. The microwave plasma processing apparatus 10 according to the second embodiment is different from the microwave plasma processing apparatus 10 according to the first embodiment in that a feeding point is provided in the sheath tube 120b and high-frequency power is supplied using the sheath tube 120b as an electrode. .

  Specifically, in the first embodiment, as illustrated in FIG. 2, high-frequency power is output from the high-frequency power source 130, and the tip portions (feeding portions) of the three feeding lines B <b> 1 to B <b> 3 through the matching unit 125. 115) to the susceptor 105. On the other hand, in the second embodiment, as shown in FIG. 5, the high-frequency power is output from the high-frequency power source 130 and connected to the four power supply lines B1 to B4 via the matching unit 125. The susceptor 105 is supplied from the sheath tube.

  FIG. 7 is a view of the BB cross section shown in FIG. 5 as seen from above the susceptor. The heater 120 is patterned symmetrically and stretched around the susceptor so that the temperature of the susceptor 105 can be uniformly controlled.

  As shown in the enlarged view of part of the heater 120 in FIG. 8, the heater 120 embedded in the susceptor 105 covers a heating element 120a such as a nichrome wire with a sheath tube 120b, and the inside thereof is magnesium oxide (MgO). Etc., which are filled with an insulator 120c. The sheath tube 120b is made of a metal such as stainless steel (SUS), nickel (Ni), or Hastelloy (registered trademark). Each power supply line B is connected to the sheath tube 120b.

  Thus, when the sheath tube 120b of the heater is used for the power transmission line, there are the following advantages. As described above, since the heater 120 is stretched around the susceptor so that the temperature of the susceptor 105 can be uniformly controlled, the heater 120 is firmly connected to the susceptor and has a large surface area. Therefore, by using the sheath tube 120b as an electrode, the current flowing per unit area can be reduced and the loss of high-frequency power can be reduced. Further, since the sheath tube 120b of the heater 120 is used as an electrode, it is not necessary to provide an electrode other than the heater in the susceptor, so that the cost is reduced.

  Of course, even when the sheath tube 120b of the heater is used as an electrode, three or more feeding points are provided on the same circumference of the sheath tube 120b, and three or more feeding lines are connected to the heater 120 at the feeding point. The For example, as shown in FIG. 7, four feed lines B1 to B4 are arranged so as to contact the sheath tube 120b at each feed point P1 to P4 on the same circumference C with respect to the center point O. . Since current flows from the back side to the front side of the paper in each power supply line B, induction magnetic fields m1 to m4 are generated in the respective power supply lines B1 to B4 around the counterclockwise direction by the right-handed screw law. To do. Each induction magnetic field is generated from each position P1 to P4 on the same circumference, and forms an induction magnetic field Ma and an induction magnetic field Mb that interfere with each other in a spiral shape and are inverted. The two induction magnetic fields Ma and Mb cancel each other. In this way, when high frequency power is supplied from the feeder line B to the susceptor 105, the induced magnetic field generated from the vicinity of the feeder line is canceled to prevent the plasma from being disturbed by the induced magnetic field and to stably control the plasma. be able to.

(Modification of the second embodiment)
Next, a modification of the second embodiment will be described. FIGS. 9A and 9B show a modification in the case where the feeder line B is connected to the heater 120. In FIG. 9 (a), eight feeder lines are sheath tubes of the heater 120 at positions P1 to P4 and positions P5 to P8 on the circumferences of two circles S and T having different center points O1 and O2. 120b is in contact. According to this, the dielectric magnetic fields generated from the feed points P located four on the circumferences of the circles S and T are canceled for each circle.

  In this way, by connecting three or more feeders to the susceptor for each circumference on a plurality of different circles, the induced magnetic field generated from the outer circumference of the feeders can be canceled as a total. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  In FIG. 9B, feed points P1 to P6 and positions P7 to P10 are provided on the circumferences of two different circles S and T with respect to the same center point O, respectively. According to this, the dielectric magnetic field generated from the six feeders located on the circumference of the circle S is canceled by the principle shown in FIG. In addition, the dielectric magnetic field generated from the four feeders located on the circumference of the circle T is also canceled by the same principle.

  In this way, three or more power supply points P are provided for each circumference on a concentric circle, and three or more power supply lines B are connected to the susceptor 105 at each power supply point, so that the power supply line B is connected to the susceptor 105. When supplying high-frequency power, the induced magnetic field generated on the outer periphery of the feeder line can be canceled. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

(Modification 1: Split susceptor)
Next, Modification 1 of the first and second embodiments will be described. As shown in FIG. 11 which is a CC cross section of FIGS. 10 and 10, the susceptor 105 itself is divided into four parts, and each divided susceptor 105 is provided with one or more power supply lines B to supply power. Good. Also in this case, the induction magnetic fields m1 to m4 generated on the outer periphery of each power supply line can be obtained by providing the power supply points P1 to P4 that are the connection positions of the power supply lines B1 to B4 and the divided susceptor 105 on the same circumference C. The induced magnetic fields Ma and Mb that interfere with each other and are opposite to each other as a whole are formed. The two induction magnetic fields Ma and Mb cancel each other. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

  Further, even when the susceptor becomes large in accordance with the increase in the area of the substrate, the in-plane uniformity of the supplied high-frequency power can be improved by providing the feeding points on the divided susceptors.

(Modification 2: Split susceptor)
Next, Modification 2 of the first and second embodiments will be described. As shown in FIG. 13, which is a DD cross section of FIGS. 12 and 12, the susceptor 105 may be divided into four, and the power supply line B may be connected to the heater provided in each divided susceptor 105. Also in this case, the connection positions (feed points P1 to P4) between the feed lines B1 to B4 and the divided susceptor 105 are arranged on one circumference C. Also by this, the induction magnetic fields Ma and Mb that are opposite to each other are formed as a whole from the induction magnetic fields m1 to m4 generated on the outer periphery of each feeder line, and the two induction magnetic fields Ma and Mb cancel each other out. Thereby, it is possible to prevent the plasma from being disturbed by the induction magnetic field and to control the plasma stably.

(Other variations)
Other modified examples of the divided susceptor are shown in FIGS. In FIG. 14A, the susceptor 105 is divided into four susceptors, one at the center and symmetrical around the periphery. Power feeding points are provided at positions P1 to P4 and positions P5 to P7 on the circumferences of the two circles S and T. According to this, the dielectric magnetic field generated from the feed line located on the circumference of each circle S, T can be canceled by the principle shown in FIG. In addition, it is not preferable to provide one or two feeding points on the central divided susceptor. This is because the magnetic field remains due to the principle shown in FIG.

  In FIG. 14B, the susceptor 105 is divided into four susceptors vertically and two susceptors protruding from both ends to the center. On the same circumference C, feed points P1 to P6 for feeding power to each divided susceptor one by one are provided. According to this, it is possible to cancel the dielectric magnetic field generated from the feeder line located on the circumference of the circle C.

  The divided susceptor may have the pattern illustrated in FIGS. In any case, the divided susceptors have symmetry, each divided susceptor has at least one feeding point, and each has three or more feeding points on each circumference of one or more circles.

Also in the divided susceptor described above, by providing three or more feeding points on each circumference of one or two or more circles, a dielectric magnetic field generated on the outer circumference of the feeding line located on each circumference is generated. It is possible to cancel, so that uniform plasma can be generated.

  According to the microwave plasma processing apparatus 10 according to each embodiment and each modification described above, the induction magnetic field can be canceled when the high frequency power is applied to the susceptor 105. Thereby, the disturbance of the plasma due to the induction magnetic field can be avoided.

  In the above embodiment, the operations of the respective units are related to each other, and can be replaced as a series of operations in consideration of the relationship between each other. And by replacing in this way, the embodiment of the invention of the plasma processing apparatus can be made an embodiment of a method for supplying power to the susceptor in the plasma processing apparatus.

  In the above embodiment, a CMEP plasma processing apparatus is used as an example of the plasma processing apparatus. However, the plasma processing apparatus is not limited to this, for example, an RLSA plasma processing apparatus (microwave plasma processing apparatus) using a radial line slot antenna, or an inductively coupled plasma (ICP) plasma. The present invention can be used in any plasma processing apparatus such as a processing apparatus, a capacitively coupled plasma processing apparatus, an electron cyclotron resonance plasma processing apparatus, and a dipole ring magnetron plasma processing apparatus.

  The object to be processed placed on the susceptor of the plasma processing apparatus according to the present invention is not limited to the substrate G, and may be a silicon wafer.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

1 is a longitudinal sectional view of a microwave plasma processing apparatus according to a first embodiment of the present invention. It is a circuit diagram of the power supply system concerning the embodiment. It is a figure for demonstrating generation | occurrence | production and cancellation of the magnetic field in the case of the embodiment. It is a figure for demonstrating the case where a magnetic field cannot be canceled. It is a longitudinal cross-sectional view of the microwave plasma processing apparatus concerning 2nd Embodiment of this invention. It is a circuit diagram of the power supply system concerning the embodiment. It is a figure for demonstrating generation | occurrence | production and cancellation of a magnetic field in the same embodiment. It is the figure which showed the heater vicinity. It is a figure for demonstrating the modification of 2nd Embodiment. It is a longitudinal cross-sectional view of the microwave plasma processing apparatus concerning the modification 1 of each embodiment. It is a figure for demonstrating generation | occurrence | production and cancellation of the magnetic field in the case of the modification. It is a longitudinal cross-sectional view of the microwave plasma processing apparatus concerning the modification 2 of each embodiment. It is a figure for demonstrating generation | occurrence | production and cancellation of the magnetic field in the case of the modification. It is another modification of a division | segmentation susceptor. It is another modification of a division | segmentation susceptor. It is the figure which showed the electric power feeding method to a general susceptor, and generation | occurrence | production of a dielectric magnetic field.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Microwave plasma processing apparatus 100 Processing container 105 Susceptor 115 Power supply part 120 Heater 120a Heat generating body 120b Sheath pipe 120c Insulator 125 Matching device 130 High frequency power supply 130a Core power supply line 135 Filter 140 SSR
145 AC power source 200 Lid body 205 Rectangular waveguide 210 Slot antenna 210a Slot 215 Dielectric plate 220 Metal beam 225 Gas introduction pipe B Feed line P Feed point m, Ma, Mb Inductive magnetic field

Claims (14)

A plasma processing apparatus for plasma processing a target object using plasma generated by exciting a gas,
A processing vessel;
A susceptor provided inside the processing container and on which an object to be processed is placed;
Three or more feeders electrically connected to the susceptor at the feeding point such that three or more feeding points are positioned on the same circumference of the susceptor;
A plasma processing apparatus, comprising: a high-frequency power source connected to the three or more power supply lines, and supplying high-frequency power to the susceptor from the three or more power supply points via the three or more power supply lines.   The three or more feeders are electrically connected to the susceptor such that three or more feeder points are positioned on each circumference of one or more circles having the same center point. The plasma processing apparatus described.   The three or more feeders are electrically connected to the susceptor such that three or more feeder points are positioned on each circumference of one or more circles having different center points. The plasma processing apparatus described. Further comprising a heater embedded in the susceptor,
The plasma processing according to any one of claims 1 to 3, wherein the three or more power supply lines are connected to the heater in the susceptor at three or more power supply points provided on the same circumference of the heater. apparatus.   The plasma processing apparatus according to claim 4, wherein the three or more feeders are connected to a sheath tube 120 b of the heater.   The plasma processing apparatus according to claim 1, wherein the three or more feeders are formed in a bar shape.   The plasma processing apparatus according to claim 1, wherein the three or more feeders are arranged in parallel to each other.   The plasma processing apparatus according to claim 1, wherein a current flows in the same direction from the high-frequency power source through the three or more feeder lines.   The plasma processing apparatus according to claim 1, wherein the three or more feeders are connected to a plurality of the high-frequency power sources or connected in parallel to a single high-frequency power source. A matching unit that is provided between the high-frequency power source and the three or more feeders, and that matches the output impedance of the high-frequency power source and the load impedance on the plasma side;
The matching unit includes a variable capacitor and an inductor provided on a main power supply line connecting the high-frequency power supply and the three or more power supply lines, and a variable capacitor provided on each power supply line of the three or more power supply lines. The plasma processing apparatus according to claim 1, comprising: The susceptor is symmetrically divided into a plurality of parts,
Among the plurality of divided susceptors, any one of the plurality of divided susceptors so that three or more feeding points are positioned on the same circumference in the same susceptor or on the same circumference across the plurality of susceptors. The plasma processing apparatus according to claim 1, wherein at least one of the three or more feeders is connected. A heater is embedded in each of the divided susceptors,
The plasma processing apparatus according to claim 11, wherein at least one of the three or more feeders is connected to any of the plurality of divided susceptors with the sheath tube 120 b of the heater as a feeding point.   The plasma processing apparatus is any one of a microwave plasma processing apparatus, an inductively coupled plasma processing apparatus, a capacitively coupled plasma processing apparatus, an electron cyclotron resonance plasma processing apparatus, and a dipole ring magnetron plasma processing apparatus. The plasma processing apparatus described in any one. A method for supplying high-frequency power to a plasma processing apparatus for plasma processing a target object using plasma generated by exciting a gas,
Electrically connecting at least three power supply lines to the susceptor at the power supply point so that three or more power supply points are positioned on the same circumference of the susceptor on which the workpiece is placed;
Outputting high-frequency power from a high-frequency power source connected to the three or more feeders;
A method of supplying the high-frequency power to the susceptor from three or more feeding points positioned on the same circumference via the three or more feeding lines.

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