JP4251817B2 - Magnet arrangement and plasma processing apparatus for generating point cusp magnetic field for plasma generation - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a magnet arrangement for creating a point cusp magnetic field for plasma generation. The magnet array is used in a plasma processing apparatus for manufacturing a semiconductor device on a silicon substrate or another substrate. A point cusp field magnet arrangement can improve process uniformity at the surface of the substrate or wafer to be processed.
[0002]
[Prior art]
Plasma assisted wafer processing is a well established process in the manufacture of semiconductor devices, usually called integrated circuits. Conventionally, there are many different plasma assisted processes, such as etching, sputter deposition, chemical vapor deposition, and the like. All of these processes must be performed to produce a uniform processing rate, such as an etching rate or a deposition rate on the wafer surface. If non-uniform processing rates occur on the wafer surface, many defective semiconductor devices are produced.
[0003]
Magnetically enhanced capacitively coupled plasmas are widely applied in wafer manufacturing processes because of their higher rf power (high frequency power) utilization efficiency. However, the majority of magnetically enhanced capacitively coupled plasmas produce a non-uniform plasma across the entire surface of the wafer. This is because electrons and ions in the plasma are subject to E × B drift, where E and B are the DC (direct current) electric field and magnetic field strength on the surface of the rf electrode, respectively. Due to this E × B drift, the plasma moves toward one side of the reaction vessel. Furthermore, the magnetic field applied to the rf electrode in most of the magnetically enhanced plasma extends to the wafer surface. This is another serious problem because it prohibits the application of other rf electrodes where a magnetic field is applied to the wafer holder. The reason for this is that again the plasma is moved to one side of the reaction vessel by E × B drift. Movement of the plasma to one side creates a non-uniform plasma across the entire surface of the wafer. Therefore, most applications of magnetically enhanced plasma are limited.
[0004]
As a solution to the above-described problem, an rf electrode having a plurality of magnets for generating a point cusp magnetic field under the electrode has been proposed. The point cusp magnetic field is limited to the vicinity of the rf electrode. The magnet configuration or arrangement creates a strong magnetic field on the surface of the rf electrode and creates an environment without a magnetic field on the surface of the wafer. This magnetic field does not cause plasma movement toward one side of the reaction vessel due to E × B drift of electrons and ions. The reason is that the E × B drift is confined to a localized area and any of the neighboring drifts are pointing in the opposite direction. Therefore, the E × B drift does not spread over a large area of the surface of the rf electrode.
[0005]
However, the aforementioned rf electrodes having a point cusp field based on a predetermined magnet arrangement can also produce a non-uniform plasma across the surface of the wafer under certain circumstances. This state will be described in detail with reference to FIGS.
[0006]
FIG. 8 is a sectional view of a conventional plasma processing apparatus. This apparatus has a reaction vessel 100 and a wafer holder 201 therein. Wafer holder 201 is disposed on bottom wall 115. The wafer holder 210 includes the rf lower electrode 102 and the insulator 104. The rf lower electrode 102 is disposed on the upper surface of the insulator 104. The lower electrode 102 is electrically insulated from the reaction vessel 100. The wafer 130 is mounted on the lower electrode 102.
[0007]
Further, the reaction vessel 100 has an upper electrode 101 above the wafer holder 201. The upper electrode 101 has a disc shape, and is supported by a ring-shaped insulator 103 fixed to the inner surface of the reaction vessel 100. This structure electrically insulates the upper electrode 101 from the rest of the reaction vessel 100. The plurality of magnets 106 are disposed on the upper surface of the upper electrode 101. Many magnets 106 are arranged in a circular area on the top surface. The magnets 106 are arranged in a form perpendicular to a line perpendicular to the upper surface, so that the polarities of the magnets 106 facing the inside of the reaction vessel 100 are opposite to those of adjacent magnets 106 on a straight line (side portion). And is the same as that of the adjacent magnet on the diagonal. These magnets generate a magnetic field having a closed magnetic flux 107 near the inner surface of the upper electrode 101. There are many closed magnetic fluxes 107 on the upper surface side and the lower surface side of the upper electrode 101.
[0008]
The upper electrode 101 is supplied with an rf current from the rf power source 113 via the matching circuit 108. The frequency of this rf current is usually in the range of 10 to 150 MHz. Further, the lower electrode 102 may or may not be supplied with the rf current from the rf power source 112 via the matching circuit 111. If the rf current is applied to the lower electrode 102, the frequency of the rf current is usually 20 MHz or less.
[0009]
Process gas is supplied into the reaction vessel 100 through a plurality of inlets 109, and the reaction vessel 100 is exhausted through a gas outlet 110. When an rf current is applied to the upper electrode 101 under a suitable low pressure, for example, a low pressure of 1 to 20 Pa, plasma is generated by the capacitive coupling mechanism. This generated plasma is then forced to be confined by the closed magnetic flux 107.
[0010]
The reaction vessel 100 further includes a ceiling wall 114 and a cylindrical side wall 105. The reaction vessel is made to have an airtight structure.
[0011]
[Problems to be solved by the invention]
Next, problems related to the configuration of the reaction vessel 100 described above will be described. The magnet arrangement described above creates a large number of point cusp fields 107 on the lower surface of the upper electrode 101. The magnetic arrangement is uniform on the upper surface of the upper electrode 101 except for the edge portion. Each magnet 106 is surrounded by four magnets of the same polarity and four magnets of the same polarity. Therefore, the magnetic field distribution pattern in the upper electrode 101 is uniform except for the portion in the vicinity of the edge. In addition, since there are four magnets with opposite polarities for each magnet, the magnetic flux 107 does not penetrate deeply into the reaction vessel 100, but instead bends within a short distance and in the direction of magnetic poles having different polarities. Head. Accordingly, a strong magnetic field exists on the lower surface of the upper electrode 101, and the strength of the magnetic field toward the lower electrode 102 is rapidly attenuated. Such a condition creates an environment without a magnetic field in an area near the surface of the wafer 130.
[0012]
The uniform distribution pattern of the magnetic field ends at the edge of the upper electrode 101. The outermost magnet has only two or three magnets with opposite polarities at very close distances. In the top view of the upper plate 101, as shown in FIG. 9 showing the magnet arrangement, the magnets on the lines indicated by the reference numerals 122, 123, 124, 125 exist with alternating polarities, Each has three magnets with opposite polarities at close distances. Therefore, each of these magnets creates a magnetic flux that forms a closed loop. On the other hand, the magnets on the line indicated by reference numerals 118, 119, 120, 121 have the same polarity toward the interior of the reaction vessel 100. Each of these magnets has only two magnets with opposite polarities at close distances. Therefore, the magnetic flux emitted from these magnets extends deeper into the reaction vessel 100 than those of the other magnets 106. Reference numeral 116 indicates the Y axis, and 117 indicates the X axis.
[0013]
When the plasma is generated, electrons and ions in the vicinity of the upper electrode 101 are forced to move under E × B drift. There is no DC (direct current) electric field in bulk plasma. Therefore, the electrons in the bulk plasma simply move according to the flux lines. Since there is no magnetic field on the surface of the wafer, electrons that are just above the wafer are not affected by the magnetic field.
[0014]
However, the magnetic flux associated with the magnets located on the lines 118, 119, 120, 121 extends toward the lower electrode 102. As electrons move along the magnetic flux, the plasma density associated with these locations will increase. That is, the plasma density over the entire surface of the wafer becomes non-uniform. As a result, the processing speed on the wafer surface is also non-uniform as well. For example, in dry etching applications, the edge speed at locations corresponding to lines 118, 119, 120, 121 will increase. This is shown schematically in FIG. In FIG. 10, the regions indicated by 126, 127, 128, and 129 have a higher etch rate compared to the rest of the wafer 130. In practical applications, it has been observed that the etch rate non-uniformity across a 300 mm diameter wafer is approximately plus or minus 15%.
[0015]
At present, the majority of wafer processing must be performed with very good processing speed uniformity on the surface of the wafer. Generally, the acceptable non-uniformity for a 200 mm diameter wafer or a 300 mm diameter wafer is less than plus or minus 5%. Therefore, the plasma source described above cannot be used for most wafer processing.
[0016]
It is an object of the present invention to generate an almost uniform magnetic flux distribution pattern under the entire rf electrode surface, thereby achieving a uniform processing speed, so that the plasma is distributed over the entire wafer surface. It is an object of the present invention to provide a magnet array and a plasma processing apparatus for generating a point cusp magnetic field for plasma generation capable of creating a uniform distribution.
[0017]
[Means for solving problems]
In order to achieve the above-described object, a magnet array and a plasma processing apparatus for generating a point cusp magnetic field for plasma generation according to the present invention are configured as follows.
[0018]
  The magnet arrangement of the present invention (corresponding to claim 1)Used in a plasma processing apparatus comprising an upper electrode facing the lower electrode and an insulating member disposed at a location not facing the lower electrode and supporting the upper electrode, and a plurality of disposed on or inside the outer surface of the upper electrode A magnet and a plurality of magnets arranged on or inside the outer surface of the insulating member, and arranged on the outer surface or inside of the insulating member and the plurality of magnets arranged on or outside the upper electrode. The plurality of magnets are arranged in a lattice pattern at regular intervals on the outer surface or inside of the upper electrode and on the entire outer surface or inside of the insulating member, at a position away from the lower electrode, and The upper electrode and a plurality of magnets arranged on the insulating member are configured to create a point cusp magnetic field near the lower side of the insulating member. It is arranged to extend Tsu bets, the insulating memberPlaced on or inside the outer surface ofThe plurality of magnets are arranged at a position higher than a plane corresponding to the upper surface of the upper electrode, and are inclined so that the tips of their magnetic axes are directed to the upper spot above the center of the upper electrode.
  Furthermore, the magnet arrangement of the present invention(Corresponding to claim 2)IsUsed in a plasma processing apparatus comprising an upper electrode having a central region portion facing the lower electrode and an outer peripheral portion not facing the lower electrode, and an insulating member disposed at a location not facing the lower electrode and supporting the upper electrode;
The outer peripheral portion of the upper electrode is held by an insulating member, and a plurality of magnets disposed on or inside the central region of the upper electrode and the outer surface or inner portion of the outer peripheral portion of the upper electrode held by the insulating member A plurality of magnets arranged on the outer surface of the central region of the upper electrode or on the outer surface of the outer peripheral portion of the upper electrode held by the insulating member The plurality of magnets are arranged in a lattice pattern at regular intervals on the outer surface or inside of the central region of the upper electrode and on the outer surface or inside of the outer peripheral portion of the upper electrode held by the insulating member. And is configured to create a point cusp magnetic field at a position away from the lower electrode and in the central region of the upper electrode and near the lower side of the insulating member. The plurality of magnets arranged on the outer peripheral portion of the held upper electrode are arranged by extending the plurality of magnets arranged on the central region portion of the upper electrode, and are arranged outside the outer peripheral portion of the upper electrode held on the insulating member. The plurality of magnets arranged on the side surface were arranged at a position higher than the plane corresponding to the upper surface of the central region portion of the upper electrode.It is characterized by that.
[0020]
  In the above magnet arrangement, the magnets related to the insulating members have their magnetic shaft tips at the ends.TopIt is inclined to face the upper spot above the center of the electrode.
[0021]
  In the above magnet arrangement,TopThe electrode has a central region portion and an outer peripheral portion, and a magnet related to the insulating member is disposed on the outer peripheral portion.
  In the above magnet arrangement, a wafer is mounted on the lower electrode.
  Furthermore, in the above magnet arrangement, the polarity of the end face magnetic poles on the same side of each magnet is opposite in the magnet adjacent to each other in the magnet arrangement of the plurality of magnets arranged on the upper electrode and the plurality of magnets arranged on the insulating member. The same is true for magnets adjacent on a diagonal line.
[0022]
  Plasma processing apparatus of the present invention(Corresponding to claim 5)Includes a lower electrode, an upper electrode facing the lower electrode, an insulating member disposed in a position not facing the lower electrode and supporting the upper electrode, a reaction vessel including a capacitively coupled plasma source, and an outer surface of the upper electrode or It has a plurality of magnets arranged inside and a plurality of magnets arranged on or inside the outer surface of the insulating member, and a plurality of magnets arranged on or on the outer surface of the upper electrode and the outside of the insulating member A plurality of magnets arranged on the side or inside are arranged in a lattice at regular intervals on the outside or inside of the upper electrode and on the outside or inside of the insulating member. A plurality of magnets arranged on the insulating member are arranged on the upper electrode, and are configured to create a point cusp magnetic field at a position away from the electrode and near the lower side of the upper electrode and the insulating member. It is arranged to extend a plurality of magnets which are insulating memberPlaced on or inside the outer surface ofThe plurality of magnets are arranged at a position higher than a plane corresponding to the upper surface of the upper electrode, and are inclined so that the tips of their magnetic axes are directed to the upper spot above the center of the upper electrode.
  Furthermore, the plasma processing apparatus of the present invention(Corresponding to claim 6)IsA lower electrode, an upper electrode having a central region facing the lower electrode and an outer peripheral portion not facing the lower electrode, an insulating member disposed in a place not facing the lower electrode and supporting the upper electrode, and a capacitively coupled plasma source The reaction vessel and the outer peripheral portion of the upper electrode are held by an insulating member, and a plurality of magnets arranged on or inside the central region of the upper electrode and the outer peripheral portion of the upper electrode held by the insulating member. A plurality of magnets arranged on the side surface or inside, on the outer surface of the central region of the upper electrode or on the outer surface of the outer peripheral portion of the upper electrode held by the plurality of magnets and the insulating member Or, a plurality of magnets arranged inside are on or inside the outer surface of the central region of the upper electrode and outside the outer peripheral portion of the upper electrode held by the insulating member A point cusp magnetic field is arranged in a grid pattern at regular intervals over the entire area inside or above, and a point cusp magnetic field is created at a position away from the lower electrode and in the central region of the upper electrode and near the lower side of the insulating member The plurality of magnets arranged in the outer peripheral portion of the upper electrode held by the insulating member are arranged by extending the plurality of magnets arranged in the central region portion of the upper electrode and held by the insulating member The plurality of magnets arranged on the outer surface of the outer peripheral portion of the upper electrode were arranged at a position higher than the plane corresponding to the upper surface of the central region portion of the upper electrode.It is characterized by that.
[0024]
In the plasma processing apparatus, the magnets associated with the insulating members are inclined so that the tips of their magnetic axes are directed to the upper spot above the center of the upper electrode.
[0025]
  In the plasma processing apparatus, the upper electrode has a central region portion and an outer peripheral portion, and a magnet related to the insulating member is disposed on the outer peripheral portion.
  In the plasma processing apparatus, a wafer is mounted on the lower electrode.
  Further, in the above plasma processing apparatus, in the magnet arrangement of the plurality of magnets disposed on the upper electrode and the plurality of magnets disposed on the insulating member, the polarity of the end face magnetic pole on the same side of each magnet is the The opposite is true for magnets that are diagonally adjacent.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. Details of the invention will become apparent through this description of the embodiments.
[0027]
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of a plasma processing apparatus having a magnet arrangement according to the first embodiment. The magnet array includes a number of magnets 6 disposed on the upper electrode 1. Each of the magnets 6 has the same shape and the same magnetic force. FIG. 2 is a plan view showing a magnet arrangement pattern on the upper electrode 1 as viewed from the upper side or the lower side. In FIG. 2, many small circles indicate the end faces of the respective magnets 6. Further, the letters N and S indicate the magnetic polarity of the magnet 6 as viewed from below. The lower magnetic poles of the magnet 6 are arranged so as to be alternately opposite. In FIG. 2, an X axis 16 and a Y axis 17 are shown.
[0028]
The basic hardware structure of the plasma processing apparatus of this embodiment is almost the same as that described in the prior art except for the magnetic arrangement.
[0029]
The plasma processing apparatus has a reaction vessel 50. The reaction vessel 50 includes an upper electrode 1, a lower electrode 2, and insulating members (or insulators) 3 and 4 that electrically insulate the electrode from the remaining portion of the reaction vessel 50. The reaction vessel 50 is formed of a top wall (ceiling wall) 14, a cylindrical side wall 5, and a bottom wall 15. The insulating member 3 arranged so as to support the upper electrode around the upper electrode 1 is usually ring-shaped. A dielectric ring plate is preferably used as the insulating member 3. The insulating member 3 is fixed to the cylindrical side wall 5. The upper electrode 1 is made of a metal, usually a non-magnetic metal such as aluminum. The lower surface of the upper electrode 1 may or may not be surrounded by a thin plate made of a different material such as Si (silicon), for example. This is to obtain the desired chemical reaction in the plasma and on the surface of the wafer. In the figure, the thin plate is not shown and is therefore not shown. In addition, the upper electrode 1 can be cooled by flowing a coolant through a passage formed in the upper electrode 1. This passage is likewise not shown in FIG.
[0030]
The upper electrode 1 is supplied with an rf current from the rf power source 13 via the matching circuit 8. The frequency of the rf current is not critical and is preferably within the range of 10 to 300 MHz. The process gas is supplied into the reaction vessel 50 through the plurality of gas inlets 9. The reaction vessel 50 is exhausted via the gas outlet 10 formed in the cylindrical side wall 5. As shown in FIG. 1, the process gas inlet 9 is provided around the side wall 5 of the reaction vessel 50. However, different mechanisms for supplying process gas into the reaction vessel 50 can be used. For example, the process gas can be supplied via a gas inlet formed in the upper electrode 1.
[0031]
The plurality of magnets 6 are disposed on the outer surfaces of the upper electrode 1 and the insulating member (dielectric ring plate) 3. The insulating member 3 exists around the upper electrode 1 as shown in FIGS. The magnets 6 are arranged in a form orthogonal to each other along a vertical line. Therefore, the polarities of the magnets 6 that are directed to the inside of the reaction vessel 50 are opposite to the magnets adjacent to each other on a straight line, and the magnets adjacent to each other diagonally It becomes the same between. The distance between two adjacent magnets having opposite polarities is not an important matter and can be varied in the range of 5 to 100 mm. The height of the magnet is likewise not important and is usually larger than 2 mm. The cross-sectional shape of the magnet 6 is a square or a circle. If the cross-sectional shape is circular, the diameter of the magnet 6 is in the range of 3-50 mm. This value is not an important matter and can be selected by considering the thickness of the upper electrode 1 and the dimensions of the reaction vessel. Normally, all magnets are made of the same magnetic material so that they have the same magnetic field strength at their magnetic poles. The strength of each magnetic field at the magnetic pole is not critical. Depending on the type of application and the size of the wafer (or substrate), the value of the magnetic field strength is varied.
[0032]
In general, the distance from the magnet 6 to the lower surface of the upper electrode 1 is determined by the thickness of the upper electrode 1. The thickness of the upper electrode 1 is not an important matter and is usually larger than 3 mm. However, as the thickness of the upper electrode increases, the strength of the magnetic field on the lower surface of the upper electrode 1 is reduced. In order to avoid the strength of the magnetic field on the lower surface of the upper electrode 1 being weakened, a hole can be formed in the upper electrode 1 and the magnet 6 can be disposed in the hole as shown in FIG. The structure for setting the magnet on the upper electrode 1 reduces the distance from the magnet to the lower surface of the upper electrode 1. Similarly, the magnet 6 can be disposed in a hole formed in the insulating member 3 as shown in FIG.
[0033]
When an rf current is applied to the upper electrode 1 under a suitable low pressure, for example, a pressure of 1 to 20 Pa, the plasma is generated by a capacitively coupled mechanism. This plasma is then confined by the closed magnetic flux 7.
[0034]
The lower electrode 2 is provided on the wafer holder 51. Wafer holder 51 is fixed to bottom wall 15. The lower electrode 2 is disposed on the upper surface of the insulating member 4 of the wafer holder 51. The insulating member 4 electrically isolates the lower electrode 2 from the remaining part of the reaction vessel 50. The wafer 23 is mounted on the lower electrode 2. Similarly, rf current is applied to the lower electrode 2 from the power source 12 via the matching circuit 11. If rf current is applied to the lower electrode 2, the frequency of the current is usually in the range of 20 MHz or less.
[0035]
In the first embodiment of the present invention, an important feature of the magnet arrangement is that the same magnet arrangement extends to the outer region of the upper electrode 1 so that it extends over the ring-shaped insulating member 3 around the upper electrode 1. It is that it has been. This magnet arrangement generates a magnetic field with a closed magnetic flux 7 near the inner surfaces of the upper electrode 1 and the insulating member 3.
[0036]
The outermost magnet 6 exists in the place of the insulating member 3 by the magnet arrangement | sequence mentioned above. In particular, the magnet 6 on the line indicated by the reference numerals 18, 19, 20, 21 is within the insulating member 3 and is separated from the upper electrode 1. These magnets are basically for expanding the magnetic field, thereby making it possible to create a non-uniform plasma. Since these magnets 6 are located away from the upper electrode 1, the expanding magnetic flux toward the lower electrode 2 is also under the insulating member 3 and away from the surface area of the upper electrode 1. . This results in a uniform pattern of magnetic flux distribution below the upper electrode 1. Since the expanded magnetic flux emitted from the outermost magnet 6 on the ring-shaped insulating member 3 is further away from the wafer 23, and no plasma is generated below the insulating member 3, the wafer 23 The effect of extended magnetic flux on the above processing speed is ignored. This results in a radially uniform plasma and uniform processing speed over the entire wafer surface.
[0037]
According to the first embodiment, the point cusp magnetic field generated by the above-described magnet arrangement on the upper electrode 1 and the ring-shaped insulating member 3 is applied to a capacitively coupled plasma processing apparatus. The point cusp magnetic field positions the magnetic flux extending toward the internal space of the reaction vessel away from the peripheral edge of the upper electrode 1, thereby minimizing the generation of non-uniform plasma across the surface of the wafer 23. Or lose.
[0038]
Next, a second embodiment of the present invention will be described with reference to FIG. The plasma processing apparatus of the second embodiment is a modification of the first embodiment. Here, only the magnet arrangement is modified, and the other hardware configuration is the same as that described in the first embodiment. Therefore, only the magnet arrangement is described here. In FIG. 4, elements that are substantially the same as those shown in FIG.
[0039]
The pattern of the magnetic arrangement is the same as that described in the first embodiment. That is, the magnets 6 are arranged in an orthogonal form along the vertical line, and therefore the polarity of each of the magnetic poles 6 toward the inside of the reaction vessel 50 is opposite to that of the adjacent magnets on a straight line, And it is the same as that of the adjacent magnet on the diagonal. The magnets 6 arranged on the upper electrode 1 exist on the same plane in the same arrangement manner. As shown in FIG. 4, the magnet 6 disposed on the ring-shaped insulating member 3 gradually becomes higher when the position of the magnet 6 is further away from the upper electrode 1. The pattern of the magnet arrangement viewed from the upper side or the lower side is not changed compared to that of the first embodiment.
[0040]
The size and strength of the magnetic field of the magnet 6 are the same as those described in the first embodiment.
[0041]
The magnet arrangement described above also produces a uniform magnetic field distribution below the upper electrode 1 as described in the first embodiment. Further, the strength of the magnetic field on the lower surface of the ring-shaped insulating member 3 is gradually reduced in the direction toward the side wall 5. This is because the height of the magnet 6 in the insulating member 3 is gradually increased in the direction toward the side wall 5. This is shown schematically in FIG. Therefore, the extended magnetic flux in the outermost magnetic field is in the ring-shaped insulating member 3 or extends slightly below the lower surface of the insulating member 3. Therefore, the movement of the plasma along the line forming the magnetic field is further suppressed. This improves the uniformity of the plasma across the entire surface of the wafer 23.
[0042]
Next, a third embodiment of the present invention will be described with reference to FIG. The plasma processing apparatus of the third embodiment is also a modification of the first embodiment. Here, only the magnet arrangement is modified as compared with the first embodiment, and the other basic hardware configuration is the same as that described in the first embodiment. Therefore, only the magnet arrangement will be described below with reference to FIG. In FIG. 5, elements that are substantially the same as those shown in FIG. 1 are respectively given the same reference numerals.
[0043]
The pattern of the magnet arrangement is the same as that described in the first and second embodiments. The magnets 6 disposed on the upper electrode 1 exist on the same plane corresponding to the upper surface of the upper electrode 1, and the magnetic axes 24 of the magnets 6 are parallel to each other. On the other hand, the magnets 6 arranged on or in the ring-shaped insulating member 3 are on another plane different from the plane described above, and their magnetic axes 24 are not parallel to those on the upper electrode 1. . The magnet 6 disposed on the ring-shaped insulating member 3 is inclined, and therefore, the upper end of each magnetic axis is directed to the upper spot above the central portion of the upper electrode 1. The inclination angle of the outermost magnet is smaller than that of the inner magnet. The arrangement of the magnets 6 in the insulating member 3 further minimizes the penetration of magnetic flux that extends into the reaction vessel 50 at the periphery of the magnet arrangement. This improves the plasma uniformity on the wafer surface. In the third embodiment, it should be noted that the thickness of the ring-shaped insulating member disposed in the region around the upper electrode 1 is relatively increased.
[0044]
Next, a fourth embodiment of the present invention will be described with reference to FIG. The plasma processing apparatus of the fourth embodiment is a modification of the second embodiment. Here, compared with the second embodiment, only the shapes of the upper electrode and the insulating member are modified, and the other hardware configuration is the same as that described in the second embodiment. The magnet arrangement is different from that of the first embodiment, but is the same as that of the second embodiment. Therefore, only the upper electrode and the insulating member will be described here in connection with the features of the magnet arrangement with reference to FIG. In FIG. 6, elements substantially the same as those shown in FIG. 4 are assigned the same reference numerals.
[0045]
The upper electrode 61 has two parts. The first portion is a central region portion 61a having a circular flat plate shape, and the other portion is an outer peripheral portion 61b. The central region portion 61a corresponds to the upper plate 1 described in the first embodiment. The outer peripheral portion 61b is formed by bending the peripheral portion of the upper electrode 61 upward in FIG. The ring-shaped insulating member 62 having a relatively large thickness has an inner surface 62a made to have an inclination. On the inner surface 62a of the insulating member 62, the inner edge is at a low position and the outer edge is at a high position. The inner surface 62a has a straight slope in its cross-sectional shape. The upper electrode 61 is attached to and supported by the inner surface of the insulating member 62 so that the outer peripheral portion 61b is held in contact with the inclined inner surface 62a. The magnet arrangement pattern of the magnets 6 is the same as that described in the second embodiment. That is, the magnet 6 disposed in the central region portion 61a exists on a plane having the same height, and corresponds to the upper surface of the central region portion 61a. The position of the magnet 6 disposed on the outer peripheral portion 61b gradually increases as the position is changed outward. All of the magnets 6 are disposed on the upper electrode 61.
[0046]
The arrangement of the magnets 6 arranged on the outer peripheral portion 61b corresponding to the ring-shaped insulating member 62 removes the magnetic flux extending at the edge portion of the magnet arrangement.
[0047]
Next, a fifth embodiment of the present invention will be described with reference to FIG. The plasma processing apparatus of the fifth embodiment is a modification of the fourth embodiment. The fifth embodiment shows the characteristic shapes of the upper electrode 61 and the insulating member 62. In the fifth embodiment, the magnet arrangement is modified as compared to the fourth embodiment, and the other hardware configurations are the same as those described in the fourth embodiment. The magnet arrangement is substantially the same as that in the third embodiment. In FIG. 7, elements that are substantially the same as those shown in FIGS. 1 and 6 are assigned the same reference numerals.
[0048]
The upper electrode 61 has a central region portion 61a and an outer peripheral portion 61b. The ring-shaped insulating member 62 has an inner surface 62a made to have an inclination. The inner surface 62a has a linear inclination in its cross-sectional shape. The magnets 6 arranged on the central region portion 61a are on the same level plane, and their magnetic axes are parallel to each other. The magnets 6 arranged on the outer peripheral portion 61b gradually become higher as the position thereof changes to the outside, and further, they are arranged so that their magnetic axes are perpendicular to the upper surface of the outer peripheral portion 61b. All of the magnets 6 are disposed on the upper electrode 61.
[0049]
The arrangement of the magnets 6 arranged on the outer peripheral part 61b corresponding to the ring-shaped insulating member 62 further minimizes and removes the magnetic flux extending at the peripheral part of the magnet arrangement.
[0050]
【The invention's effect】
According to the present invention, a magnet array for generating a point cusp magnetic field or a plasma processing apparatus equipped with the magnet array minimizes or eliminates the magnetic flux existing in a predetermined peripheral region of the upper electrode, so that the surface of the wafer Overall plasma distribution uniformity can be improved, thereby improving processing uniformity at the wafer surface.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a plasma processing apparatus according to a first embodiment.
FIG. 2 is a plan view showing a magnet arrangement on an upper electrode and an insulating member in the first embodiment.
FIG. 3 is a cross-sectional view of a plasma processing apparatus as a modification of the first embodiment.
FIG. 4 is a cross-sectional view of a plasma processing apparatus according to a second embodiment.
FIG. 5 is a cross-sectional view of a plasma processing apparatus according to a third embodiment.
FIG. 6 is a sectional view of a plasma processing apparatus according to a fourth embodiment.
FIG. 7 is a sectional view of a plasma processing apparatus according to a fifth embodiment.
FIG. 8 is a cross-sectional view of a conventional plasma processing apparatus.
FIG. 9 is a plan view showing a magnet arrangement on an upper electrode in a conventional apparatus.
FIG. 10 is a plan view of a wafer to show technically problematic areas.
[Explanation of reference signs]
1 Upper electrode
2 Lower electrode
3 Insulating material
4 Insulating material
6 Magnet
7 Magnetic flux
23 wafers
51 Wafer holder
61 Upper electrode
62 Insulating material

Claims (8)

Used in a plasma processing apparatus comprising an upper electrode facing the lower electrode, and an insulating member disposed at a location not facing the lower electrode and supporting the upper electrode;
A plurality of magnets arranged on or inside the outer surface of the upper electrode, and a plurality of magnets arranged on or inside the outer surface of the insulating member,
The plurality of magnets arranged on or inside the outer surface of the upper electrode and the plurality of magnets arranged on or outside the outer surface of the insulating member are arranged on the outer surface or inside of the upper electrode, and the insulation. It is arranged in a grid at regular intervals over the entire outer surface or inside of the member, and the point cusp is located at a position away from the lower electrode and near the lower side of the upper electrode and the insulating member. Configured to create a magnetic field,
The plurality of magnets arranged on the insulating member are arranged by extending the plurality of magnets arranged on the upper electrode,
The plurality of magnets arranged on or inside the outer surface of the insulating member are arranged at a position higher than a plane corresponding to the upper surface of the upper electrode, and their magnetic axes are located at the upper spot above the center of the upper electrode. A magnet array for creating a point cusp magnetic field for plasma generation, which is tilted so that the tip of the magnet is directed. Used in a plasma processing apparatus comprising an upper electrode having a central region portion facing the lower electrode and an outer peripheral portion not facing the lower electrode, and an insulating member disposed at a location not facing the lower electrode and supporting the upper electrode And
The outer peripheral portion of the upper electrode is held by the insulating member,
A plurality of magnets disposed on or inside the central region of the upper electrode , and a plurality of magnets disposed on or inside the outer surface of the outer peripheral portion of the upper electrode held by the insulating member; With
The plurality of magnets disposed on or inside the outer surface of the upper electrode held by the insulating member and the plurality of magnets disposed on or inside the central region of the upper electrode. Are arranged in a lattice pattern at regular intervals on the outer surface or inside of the central region portion of the upper electrode and on the outer surface of the outer peripheral portion of the upper electrode held by the insulating member or in the entire region. Arranged to create a point cusp magnetic field at a position away from the lower electrode and in the central region of the upper electrode and near the lower side of the insulating member,
The plurality of magnets arranged on the outer peripheral portion of the upper electrode held by the insulating member are arranged by extending the plurality of magnets arranged on the central region portion of the upper electrode ,
Wherein the plurality of magnets disposed on the outer surface of the outer peripheral portion of the upper electrode held before Symbol insulating member was placed at a position higher than a plane corresponding to the upper surface of the central region portion of the upper electrode A magnet array that creates a point cusp magnetic field for plasma generation.   3. A magnet array for generating a point cusp magnetic field for generating plasma according to claim 1, wherein a wafer is mounted on the lower electrode.   In the magnet arrangement of the plurality of magnets arranged in the upper electrode and the plurality of magnets arranged in the insulating member, the polarity of the end face magnetic pole on the same side of each magnet is opposite in the nearest adjacent magnet, The magnet arrangement for generating a point cusp magnetic field for plasma generation according to any one of claims 1 to 3, wherein magnets adjacent on a diagonal line are the same. A lower electrode, an upper electrode facing the lower electrode, an insulating member disposed in a place not facing the lower electrode and supporting the upper electrode, a reaction vessel including a capacitively coupled plasma source,
A plurality of magnets disposed on or inside the upper surface of the upper electrode, and a plurality of magnets disposed on or inside the outer surface of the insulating member,
The plurality of magnets arranged on or inside the outer surface of the upper electrode and the plurality of magnets arranged on or outside the outer surface of the insulating member are arranged on the outer surface or inside of the upper electrode, and the insulation. It is arranged in a grid at regular intervals over the entire outer surface or inside of the member, and the point cusp is located at a position away from the lower electrode and near the lower side of the upper electrode and the insulating member. Configured to create a magnetic field,
The plurality of magnets arranged on the insulating member are arranged by extending the plurality of magnets arranged on the upper electrode,
The plurality of magnets arranged on or inside the outer surface of the insulating member are arranged at a position higher than a plane corresponding to the upper surface of the upper electrode, and their magnetic axes are located at the upper spot above the center of the upper electrode. A plasma processing apparatus, which is tilted so that the tip thereof is directed. A lower electrode, an upper electrode having a central region facing the lower electrode and an outer peripheral portion not facing the lower electrode, an insulating member disposed at a location not facing the lower electrode to support the upper electrode, and capacitively coupled plasma A reaction vessel containing a source;
The outer peripheral portion of the upper electrode is held by the insulating member,
A plurality of magnets disposed on or inside the central region of the upper electrode , and a plurality of magnets disposed on or inside the outer surface of the outer peripheral portion of the upper electrode held by the insulating member; With
The plurality of magnets disposed on or inside the outer surface of the upper electrode held by the insulating member and the plurality of magnets disposed on or inside the central region of the upper electrode. Are arranged in a lattice pattern at regular intervals on the outer surface or inside of the central region portion of the upper electrode and on the outer surface of the outer peripheral portion of the upper electrode held by the insulating member or in the entire region. Arranged to create a point cusp magnetic field at a position away from the lower electrode and in the central region of the upper electrode and near the lower side of the insulating member,
The plurality of magnets arranged on the outer peripheral portion of the upper electrode held by the insulating member are arranged by extending the plurality of magnets arranged on the central region portion of the upper electrode ,
Wherein the plurality of magnets disposed on the outer surface of the outer peripheral portion of the upper electrode held before Symbol insulating member was placed at a position higher than a plane corresponding to the upper surface of the central region portion of the upper electrode A plasma processing apparatus.   The plasma processing apparatus according to claim 5, wherein a wafer is mounted on the lower electrode.   In the magnet arrangement of the plurality of magnets arranged in the upper electrode and the plurality of magnets arranged in the insulating member, the polarity of the end face magnetic pole on the same side of each magnet is opposite in the nearest adjacent magnet, The plasma processing apparatus according to claim 5, wherein magnets adjacent on a diagonal are the same.

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