JP4397271B2 - Processing equipment - Google Patents

Description

  The present invention relates to an apparatus for performing vacuum processing on a substrate, for example, by holding the substrate on an electrostatic chuck.

  There are many semiconductor device manufacturing processes that perform substrate processing in a vacuum atmosphere, such as etching or CVD (Chemical Vapor Deposition) film formation, and a vacuum processing apparatus that performs such processing. For example, as shown in FIG. 17, a mounting table 91 for a semiconductor wafer (hereinafter referred to as a wafer) W that also serves as a lower electrode is disposed in a processing container 9, and an upper electrode is disposed above the mounting table 91. An constituted gas supply chamber 92 is provided. Then, a high frequency for plasma generation is applied to the mounting table 91 from the high frequency power supply 91a to generate plasma between the mounting table 91 and the gas supply chamber 92, and the plasma supplies the inside of the processing vessel 9 from the gas supply chamber 92. The processing gas introduced into the substrate is activated, whereby a predetermined process is performed on the wafer W mounted on the mounting table 91.

  By the way, the mounting table 91 is configured such that an electrostatic chuck layer 94 and a conductive ring body 95 provided so as to surround the side of the electrostatic chuck layer 94 are provided on the upper surface of the support portion 93. The electrostatic chuck layer 94 has a configuration in which a sheet-like chuck electrode 94a made of tungsten, for example, is sandwiched between insulating layers 94b made of a dielectric material such as alumina. A voltage (chuck voltage) is applied, and the wafer W can be sucked and held by the Coulomb force generated thereby. In FIG. 17, reference numeral 96 denotes an exhaust path for exhausting the atmosphere in the processing container 9 to the outside.

  For example, such an electrostatic chuck layer 94 generally includes an upper surface of the support portion 93, alumina constituting the lower surface side insulating layer 94b, tungsten constituting the chuck electrode 94a, and an upper side insulating layer 94b. It is formed by thermally spraying the constituent alumina.

  However, the electrostatic chuck layer 94 formed by the above-described method has a large residual attracting force even after the application of the DC voltage to the chuck electrode 94a is stopped. Further, since the surface of the sprayed surface protrudes when sprayed, film peeling occurs from the tip to form particles, and the particles adhere to the back side of the wafer. Further, when plasma processing is performed, in order to remove the deposition attached to the inside of the processing container 9 such as the region near the mounting table 91, nothing is mounted on the upper surface of the electrostatic chuck layer 94. In some cases, oxygen gas is introduced into the processing container 9 and cleaning is performed with the plasma of the oxygen gas. However, there is a problem that the surface of the electrostatic chuck layer 94 is damaged by the plasma of the oxygen gas.

  For this reason, the use of a sintered plate as an electrostatic chuck layer has been studied, and Patent Document 1 describes a specific structure. Here, in the mounting table using the sintered type electrostatic chuck layer, for example, as shown in FIG. 18, an electrostatic chuck layer made of a sintered plate 97 having a structure in which an electrode 97a made of tungsten, for example, is covered with an insulating layer 97b. 97 is joined to a support portion 93 made of, for example, aluminum or the like with a joining layer 98 made of a silicon-based adhesive resin.

  By the way, in the mounting table 91 described above, a refrigerant flow path (not shown) is formed in the support section 93, and the surface of the support section 93 is made predetermined by passing a refrigerant adjusted to a predetermined temperature through the refrigerant flow path. The reference temperature is adjusted. The wafer temperature is controlled to a predetermined temperature by releasing the heat of the wafer, which becomes high temperature by heat input from the plasma, to the support portion 93.

  However, in the above-described sintered type electrostatic chuck layer 97, a bonding layer 98 is provided between the electrostatic chuck layer 97 and the support portion 93. A silicone-based adhesive resin constituting the bonding layer 98 is provided. Since the heat conductivity is low, the heat of the wafer W is not easily transmitted to the support portion 93, the equilibrium temperature is high, and it takes time to adjust the temperature until the wafer temperature is stabilized at a predetermined process temperature. Thus, if it takes a long time to adjust the temperature of the wafer, the process cannot be shifted to immediately after the start of processing, resulting in a decrease in throughput.

  Further, a focus ring 95 is provided around the side peripheral surface of the bonding layer 98. However, since there is a slight gap between the two, the side peripheral surface of the bonding layer 98 activates the processing gas during processing. It will be exposed to the active species generated by. Here, since the silicone-based adhesive resin constituting the bonding layer 98 has particularly low resistance to fluorine (F) radicals, in a process for generating fluorine radicals, for example, etching using a process gas containing fluorine, the silicone-based adhesive resin is formed by fluorine radicals. The side peripheral surface of the adhesive resin is eroded. Since the side peripheral portion of the eroded adhesive resin has poor thermal conductivity, the heat input from the plasma to the wafer is difficult to escape from the side peripheral surface of the adhesive resin. Accordingly, the temperature of the outer peripheral portion of the wafer W increases with the erosion of the bonding layer 98, resulting in poor processing uniformity, for example, in-plane uniformity of the etching rate, and the electrostatic chuck layer 97 needs to be replaced early. There is a problem of becoming.

Japanese Patent Laid-Open No. 7-335731 (Claim 1, paragraph 0080, paragraph 0081, paragraph 0082)

  The present invention has been made based on such circumstances, and the purpose thereof is to increase the thermal conductivity of the bonding layer that bonds the electrostatic chuck layer and the support portion, thereby stabilizing the substrate at a predetermined temperature. It is to provide a technique capable of shortening the time required until. Another object of the present invention is to provide a technique capable of suppressing deterioration of the bonding layer due to active species generated by plasma.

Further, the processing apparatus of the present invention includes a processing container for performing plasma processing on a substrate,
An electrostatic chuck layer that is provided in the processing container and that covers the chuck electrode with an insulating layer for holding the substrate by the electrostatic adsorption force by applying a voltage to the chuck electrode;
A support portion made of a material different from that of the electrostatic chuck layer for supporting the electrostatic chuck layer;
A bonding layer provided for bonding the support portion and the electrostatic chuck layer between the support portion and the electrostatic chuck layer;
And a flexible heat-shrinkable tube provided so as to cover a side peripheral surface of the bonding layer in order to protect the bonding layer from active species generated by plasma.

It is preferable to use a fluorocarbon resin as the material of the previous SL heat shrinkable tube. Preferable examples of the fluororesin include PFA, FEP and PTFE. Moreover, when using materials other than a fluororesin as a coating | coated member, it is preferable to coat the surface part with a fluorine.

  Furthermore, in the invention using the covering member, the electrostatic chuck layer and the support portion are projected outward from the bonding layer, thereby forming a recess, and the covering member is supported by the electrostatic chuck layer and the support in the recess. It is good also as a structure fitted in the said recessed part in the state which is pressing the surface of a part with the restoring force. As the bonding layer, for example, a silicone-based adhesive resin or an acrylic resin can be used.

  Further, in the case where a high frequency power supply is supplied to the support portion in order to generate plasma, the relative dielectric constant between the electrostatic chuck layer and the support portion is equal to the relative dielectric constant of the bonding layer. A configuration in which a spacer is interposed may be employed. In this case, the spacer is, for example, a ceramic piece, and the bonding layer is, for example, a mixture of an adhesive resin and ceramic powder as a filler material. In addition, as the adhesive resin, for example, a silicone-based adhesive resin or an acrylic adhesive resin is used. Equivalent here means that 0.9ε2 ≦ ε1 ≦ 1.1ε2 is established, where ε1 is the dielectric constant of the spacer and ε2 is the relative dielectric constant of the bonding layer. Thus, if the relative dielectric constants of the spacer and the bonding layer are made equal, the impedance to the high frequency voltage becomes uniform in the plane direction, and hence the efficiency of the high frequency power becomes uniform in the plane direction. High plasma treatment can be performed.

According to the present invention, since the flexible heat-shrinkable tube is provided so as to cover the side peripheral surface of the bonding layer, the deterioration of the bonding layer due to active species generated by plasma can be suppressed. Furthermore, since this heat-shrinkable tube is made of a flexible material, even if thermal expansion occurs in the electrostatic chuck layer and the support part due to heating, it can be absorbed and followed, so there is no risk of brittle fracture or gap formation. The state can be maintained.

[First Embodiment]
A first embodiment of a processing apparatus according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a longitudinal sectional view showing the overall structure of an example of an etching apparatus which is a processing apparatus according to the present embodiment. In the figure, reference numeral 1 denotes a vacuum chamber forming a processing container, which is formed to form an airtight structure, for example, from aluminum. In this vacuum chamber 1, an upper electrode 11 that also serves as a gas shower head (processing gas supply unit) and a mounting table 2 that also serves as a lower electrode are provided facing each other, and communicates with a vacuum pump (not shown) on the bottom surface. An exhaust port 10 is formed. Openings 12 and 13 for carrying in and out a semiconductor substrate as a substrate, for example, a wafer W as a silicon substrate, are formed in the side wall portion of the vacuum chamber 1 and can be opened and closed by a gate valve G, respectively. . For example, ring-shaped permanent magnets 14 and 15 are provided outside the side wall portions at positions where the openings 12 and 13 are sandwiched vertically.

The upper electrode 11 has a large number of holes 16 formed on the bottom surface, and a gas supply pipe 17 extending from a gas supply source (not shown) connected to the upper surface. The processing gas supplied from the gas supply pipe 17 is It diffuses in the processing gas flow path 18 formed in the upper electrode 11 and is configured to go to the surface of the wafer W placed on the surface of the mounting table 2 through the hole 16. Further, the upper electrode 11 is grounded. Next, the mounting table 2 which forms the main part of the present embodiment will be described in detail. The mounting table 2 is formed, for example, in a columnar shape, and includes an electrostatic chuck layer 3 on the upper surface of a support portion 21 that forms a conductive support portion made of metal, for example. The support portion (mounting table main body) 21 is made of, for example, aluminum, and a refrigerant flow path 22 is formed therein. A refrigerant adjusted to a predetermined temperature by a temperature adjustment section 23 is formed in the refrigerant flow path 22 as a refrigerant. The surface temperature of the support portion 21 is controlled to a predetermined reference temperature, for example, about 10 ° C. to 60 ° C. by passing through the supply means 24. The refrigerant flow path 22, the refrigerant supply means 24, and the refrigerant temperature control section 23 correspond to the cooling means of the present invention.

  The electrostatic chuck layer 3 is configured as a sintered body of a sheet-like chuck electrode 31 made of tungsten, for example, and an insulator provided so as to sandwich the front and back surfaces of the chuck electrode 31, for example, an insulating layer 32 made of alumina, For example, it consists of a plate-like body having a thickness of about 1 mm to 2 mm. The chuck electrode 31 is connected to a DC power source 33 via a resistor R1. The mounting table 2 has a configuration in which the electrostatic chuck layer 3 is provided in combination, and the wafer W is attracted and held by the surface portion (upper surface) of the insulating layer 32.

  The electrostatic chuck layer 3 made of the sintered body is prepared, for example, by mixing two powders of alumina powder and a binder and press-fired as an upper layer portion and a lower layer portion. A mixture of tungsten powder and binder is applied to the upper surface. Subsequently, the upper layer side pressure fired body is provided on the upper surface, and further formed by pressure firing.

  A bonding layer 4 for bonding the support portion 21 and the electrostatic chuck layer 3 is provided between the support portion 21 and the electrostatic chuck layer 3. The bonding layer 4 is made of, for example, a plate-like body having a thickness of about 0.3 mm to 0.8 mm, which is made of a porous ceramic 41 having a high thermal conductivity impregnated with an adhesive resin. The upper surface of the portion 21 and the lower surface of the electrostatic chuck layer 3 are provided so as to contact the back surface of the porous ceramic 41. The porous ceramics 41 is made of a material having a thermal conductivity of about 0.02 W / m · K to 280 W / m · K, for example, aluminum nitride (AlN), silicon carbide (SiC), alumina (Al 2 O 3), or the like. The

  An example of a method for producing such a porous ceramic will be described as follows. First, a sintering aid or an impurity is prepared in the raw material powder and molded by a CIP (Cold Isostatic Press) method or the like. Subsequently, the molded body is fired while being subjected to normal pressure or pressurization, and thereafter subjected to machining such as surface polishing and then washed. As the adhesive resin, a silicone adhesive resin or an acrylic adhesive resin having a thermal conductivity of about 0.2 W / m · K to 2.0 W / m · K can be used.

  The bonding layer 4 is formed, for example, by impregnating the porous resin 41 formed by the above-described method with the adhesive resin. An example of a method for forming the bonding layer 4 will be described with reference to FIG. To do. FIG. 3A shows the state of the porous ceramic 41, and an adhesive resin is applied to the surface of the porous ceramic 41 (see FIG. 3B). When the adhesive resin is applied to the porous ceramic 41 in this way, the adhesive resin enters the hole 42 in the vicinity of the surface of the porous ceramic 41 and gradually penetrates into the porous ceramic 41. In this way, the adhesive resin enters the hole 42 of the porous ceramic 41. This state is referred to as a state in which the porous ceramic 41 is impregnated with the adhesive resin (see FIG. 3C). In this forming method, a thermoplastic resin is used as the adhesive resin.

  After the porous ceramic 41 is impregnated with the adhesive resin in this way, the protective layer 5 is formed around the side peripheral surface of the bonding layer 4. This protective layer 5 (not shown in FIG. 1 for convenience of illustration) suppresses the contact between the side peripheral surface of the bonding layer 4 and the active species (radicals) generated by the plasma treatment of the processing gas. It is formed to prevent alteration. For this reason, the protective layer 5 is formed of a material that is not etched by radicals, for example, an inorganic material such as silica. For example, as shown in FIG. 3 (d), a liquid protective layer solution in which the components of the protective layer 5 made of the inorganic material are dissolved in a solvent is used as a side periphery of the bonding layer 4 formed as described above. By applying to the surface, the protective layer solution is impregnated, for example, to the region 43 about 1 mm inside from the side peripheral surface of the bonding layer 4 (see FIG. 3E).

  Next, the protective layer solution is solidified by subjecting the bonding layer 4 to a heat treatment (curing treatment) at a temperature of about 80 ° C., for example, as shown in FIG. Thus, the bonding layer 4 is formed, and a region impregnated with the protective layer solution of the bonding layer 4 is formed as the protective layer 5.

  Since the bonding layer 4 formed in this manner is impregnated with a porous ceramic having a high thermal conductivity and an adhesive resin, even if the thermal conductivity of the adhesive resin is low, the total thermal conductivity of the bonding layer is, for example, It is about 20 W / m · K to 40 W / m · K.

  Returning further to FIG. 1, a ring member 6 serving as a conductive member is provided around the electrostatic chuck 3 of the mounting table 2. The ring member 6 plays a role of spreading the plasma generated in the vacuum chamber 1 more than the wafer W mounted on the mounting table 2 and improving the uniformity of the etching rate within the wafer surface. The conductor is made of, for example, silicon (Si). Further, an elevating member (not shown) for transferring the wafer W is provided inside the mounting table 2. Plasma, for example, is generated in the supporting unit 21 of the mounting table 2 via the capacitor C 1 and the coil L 1. A high frequency power supply 25 for applying a high frequency for operation is connected.

  Here, an example of a specific manufacturing method of the mounting table 2 will be described with reference to FIG. For example, as shown to Fig.4 (a), adhesive resin is apply | coated on the support part 21, and the porous ceramic 41 is mounted on this. Next, an adhesive resin is applied to the surface of the porous ceramic 41 to form the bonding layer 4 in which the porous ceramic 41 is impregnated with the adhesive resin. Next, as shown in FIG. 4B, the electrostatic chuck layer 3 made of a sintered body formed by the above-described method is placed on the bonding layer 4. Subsequently, as shown in FIG. 4C, a protective layer solution for forming the protective layer 5 is applied around the bonding layer 4. Subsequently, as shown in FIG. 4D, a curing process is performed at a predetermined temperature, for example, 130 ° C. for a predetermined time, the adhesive resin of the bonding layer 4 is softened and then cooled to solidify the adhesive resin again and the protective layer. 5 is formed, and thus the mounting table 2 is manufactured (see FIG. 4E). As shown in FIG. 3 or FIG. 4, the bonding layer can be formed separately or on the support.

Next, the operation of this embodiment will be described. First, the gate valve G is opened, and the wafer W is placed on the surface of the electrostatic chuck layer 3 in the vacuum chamber 1 by the transfer arm (not shown) through the opening 12 (or 13). Then, after the transfer arm is retracted and the gate valve G is closed, the vacuum chamber 1 is evacuated through the exhaust port 10 so that the internal pressure is maintained at, for example, 10 ⁻² to 10 ⁻³ Pa. Make adjustments. At this time, a DC voltage is applied to the chuck electrode 31, and the wafer W is held on the surface of the three layers of the electrostatic chuck by the Coulomb force.

  Then, a processing gas such as C4F8 gas is supplied toward the wafer W, and a high frequency voltage is applied from the high frequency power source 25 to the mounting table 2 forming the lower electrode to increase the density of the plasma. As a result, the processing gas is activated, and, for example, the silicon oxide film on the surface of the wafer W is etched by the activated species.

  At this time, the wafer W is exposed to plasma, for example, the wafer W is heated to a high temperature. However, since the surface of the support portion 21 is set to a reference temperature, for example, 60 ° C. by the refrigerant flow path 22, Quickly moves to the support portion 21 via the electrostatic chuck layer 3 and the bonding layer 4, and the temperature of the wafer W during processing is predetermined by the heating of the wafer W by the plasma and the reference temperature of the support portion 21. The process temperature is controlled to 100 ° C., for example. After the etching is thus completed, the wafer W is unloaded from the vacuum chamber 1 in the reverse order of loading.

  In such a configuration, since the support portion 21 and the electrostatic chuck layer 3 are bonded to each other by the bonding layer 4 in which the porous ceramic 41 having high thermal conductivity is impregnated with the adhesive resin, a high adhesive force is obtained. While securing, the thermal conductivity of the bonding layer 4 can be increased. That is, as the adhesive between the electrostatic chuck layer 3 and the support portion 21, it is desirable to use a silicone adhesive resin having a high adhesive force, but this silicone adhesive resin has a low thermal conductivity. For this reason, the silicone adhesive resin is not used as it is, but impregnated in the porous ceramics 31 having high thermal conductivity, and the bonding layer 4 is formed by a combination of the porous ceramics 31 and the adhesive resin. Adhesive strength and high thermal conductivity can be secured at the same time.

  Therefore, by using the bonding layer 4 described above, the support portion 21 and the electrostatic chuck layer 3 are sufficiently bonded by the silicone-based adhesive resin, and between the support portion 21 and the electrostatic chuck layer 3. Thus, heat conduction is quickly performed through the porous ceramics 41. As a result, the heat of the wafer, which has become a high temperature due to the heat input of the plasma, quickly escapes toward the support portion 21 via the electrostatic chuck layer 3 and the bonding layer 4. The transfer of heat is performed promptly, the adjustment of the wafer W temperature is facilitated, and the temperature of the wafer, which becomes high due to the heat input of the plasma, is cooled and stabilized to a predetermined temperature in a short time. Thus, since the wafer W temperature is stabilized in a short time from the start of the process, the process can be started immediately, the total processing time can be shortened, and the throughput can be improved.

  This state is shown in FIG. 5, where the solid line shows the relationship between the wafer temperature and the processing time when the bonding layer 4 of the present invention is used, and the dotted line shows the case where only the silicone-based adhesive resin is used as the bonding layer. Is shown. As described above, when the bonding layer 4 of the present invention is used, the temperature of the wafer is instantaneously stabilized at a predetermined process temperature by the heat input of the plasma and the cooling by the support portion 21 via the bonding layer 4. On the other hand, when the silicone adhesive resin is used as the bonding layer, the heat conductivity of the silicone adhesive resin is low, so that the heat of the wafer that has become high temperature due to plasma is difficult to move to the support portion 21, and the processing time is increased. As the length increases, the wafer temperature gradually increases, and it becomes difficult to stabilize at a predetermined temperature.

  As described above, in the above-described configuration, the thermal conductivity of the bonding layer 4 is high, and heat is quickly exchanged between the wafer W and the support portion 21. Therefore, the wafer W can be easily cooled, and the wafer W and the support portion can be cooled. The temperature difference of 21 can be reduced in a short time. Thereby, in this case, since the reference temperature of the support portion 21 can be set higher than the conventional temperature, and the cooling capacity of the cooling means of the support portion 21 can be set low, the load on the cooling system is reduced and more Temperature control becomes easy.

  Here, the adhesive strength and thermal conductivity of the bonding layer 4 depend on the degree of impregnation of the adhesive resin into the porous ceramic 41, and if the degree of impregnation of the adhesive resin into the porous ceramic 41 is large, the adhesive strength. Increases and the thermal conductivity decreases. Further, if the degree of impregnation of the adhesive resin into the porous ceramic 41 is small, the adhesive force is reduced and the thermal conductivity is increased.

  On the other hand, the degree of impregnation of the adhesive resin into the porous ceramic 41 depends on the porosity of the porous ceramic 41. If the porosity is large, the degree of impregnation is large, and if the porosity is small, the degree of impregnation is high. Get smaller. For this reason, in order to increase the thermal conductivity while ensuring a sufficient adhesive force, for example, it is required to optimize the porosity of the porous ceramic 41.

  Furthermore, since the heat of the wafer W moves to the support portion 21 via the electrostatic chuck layer 3 and the bonding layer 4, the temperature of the wafer W can be easily controlled between the electrostatic chuck layer 3 and the bonding layer 4. Since the thermal conductivity of the electrostatic chuck layer 3 made of the above-described sintered body is preferably about 20 W / m · K or more and about 40 W / m · K or less, it is desirable that the thermal conductivity be uniform. The conductivity is preferably about 20 W / m · K or more and 40 W / m · K or less.

  Furthermore, in the above-described bonding layer 4, even if the radicals of the component of the processing gas generated by the plasma enter between the bonding layer 4 and the ring body 6 and come into contact with the outer peripheral surface of the bonding layer 4, Since the surface is resistant to radicals and the protective layer 5 is formed of a material that is not etched by the radicals, the bonding layer 4 itself can be prevented from contacting the radicals. For this reason, the thermal conductivity and adhesive force of the bonding layer 4 are hardly changed over time, a stable treatment can be performed over a long period of time, and the life of the mounting table 2 can be extended.

  Next, an experiment for confirming the effect of the present invention will be described. As the porous ceramic 41, a disk shape having a diameter of 300 mm, a thickness of 0.5 mm, an average pore size of 30 μm, and a porosity of 50%. The mounting table 2 was manufactured by the method described with reference to FIG. At this time, as the electrostatic chuck layer, a 1 mm-thick sintered body in which an electrode made of tungsten was coated with alumina was used. The heat treatment for solidifying the adhesive resin and the protective layer 5 was performed at 130 ° C. for 15 minutes, for example.

  The thermal conductivity of the bonding layer 4 formed in this way was measured and found to be 22 W / m · K, 10 times that of a silicone adhesive resin having a thermal conductivity of about 2.0 W / m · K. It was confirmed that a high thermal conductivity could be secured.

  Furthermore, in the processing apparatus incorporating the mounting table 2 of the present invention, the above-described etching process was performed for 3000 H in total, and the thermal conductivity of the bonding layer 4 was measured for each process. Since no change is observed, it is recognized that the formation of the protective layer 5 suppresses the deterioration of the bonding layer 4 due to radicals, and the life of the mounting table 3 can be extended.

  In the present invention, in the present invention, the electrostatic chuck layer 3 is not limited to one formed of a sintered body, and may be formed by thermal spraying. In this case, after the bonding layer 4 is placed on the support portion 21, the electrostatic chuck layer 3 is sprayed on the upper surface of the bonding layer 4. Further, the present invention can be applied not only to an etching process but also to a process such as ashing in addition to a film forming process and an ion implantation process.

[Second Embodiment]
Further, another embodiment of the present invention will be described. FIG. 6 is a diagram showing the mounting table 7 used in this embodiment. Other parts of the processing apparatus (etching apparatus) according to this embodiment have the same configuration as that of FIG. In FIG. 6, the same reference numerals as those in FIG. 2 denote the same parts. The bonding layer 70 is for bonding the electrostatic chuck layer 3 and the support portion 21 and is made of, for example, a silicone rubber adhesive. A flexible covering member 71 is provided on the side peripheral surface of the bonding layer 70 to protect the bonding layer 70 from active species generated by plasma, such as fluorine radicals and fluorine ions. Further, as shown in FIG. 6B, which is an enlarged view of a part of FIG. 6A, the central portion of the upper surface of the support base 21, that is, the peripheral portion of the convex portion that is a portion bonded to the electrostatic chuck layer 3 A sprayed film 72 is formed on the surface. The sprayed film 72 is formed as an insulating part in order to prevent the occurrence of abnormal plasma discharge.

  As the covering member 71, for example, a heat shrinkable tube made of a fluororesin is used. Specific examples of this fluororesin include, for example, tetrafluoroethylene perfluoroalkoxy vinyl ether (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and tetrafluoroethylene (PTFE). Can do. As an advantage of using the fluororesin, the fluororesin has high heat resistance. For example, PFA can withstand temperatures up to 260 ° C. and FEP up to 200 ° C., and has low gas permeability. It is not permeated, and it is difficult to wear even if the surface of the fluororesin reacts with active species. Further, since the fluororesin contains few impurities, the use of the fluororesin for a long time has a characteristic that the impurity does not scatter even if the surface of the fluororesin reacts with the active species and is consumed. The heat-shrinkable tube has a characteristic that it shrinks when heat at a predetermined temperature is applied and does not return to its original size once it shrinks. For example, when the example of the characteristic of the heat shrinkable tube used when the mounting table 7 is a size for mounting a wafer having a diameter of 200 mm, a heat shrinkable tube made of FEP having a diameter of 206 mm is set to a temperature of 150 to 200 ° C., for example. When heated at, the diameter shrinks from 206 mm to 160 mm. Alternatively, when a heat-shrinkable tube made of PFA and having a diameter of 211 mm is heated at a temperature of, for example, 150 to 200 ° C., the diameter shrinks from 211 mm to 185 mm. Due to this shrinkage characteristic, for example, even if the outer periphery of the mounting table 7 is not completely circular, the entire side peripheral surface can be covered.

  Next, a specific method for mounting the heat shrinkable tube as the covering member 71 on the side peripheral surface of the bonding layer 70 will be described with reference to FIG. As shown in FIG. 7 (a), for example, electrostatically so as to surround the central convex portion of the support portion 21 on which the electrostatic chuck layer 3 is provided via the bonding layer 70 and the outer periphery of the electrostatic chuck layer 3. A ring-shaped heat-shrinkable tube that is slightly larger than the diameter of the chuck layer 3 and is formed by cutting the heat-shrinkable tube into a circle is placed on the support portion 21. In this state, the mounting table 7 is placed in a thermostat and heated at a temperature of, for example, about 130 ° C., so that the heat-shrinkable tube contracts by heat and contracts as shown in FIG. 7B. By this contraction force toward the inside, it comes into close contact with the side peripheral surface of the electrostatic chuck layer 3 and the side peripheral surface of the convex portion of the support portion 21 covered with the sprayed film 72. At this time, a D-cut portion 3a (a linear portion provided on a part of the side peripheral surface of the electrostatic chuck layer 3) is provided on a part of the mounting table 7 in correspondence with the notch and the orientation flat part of the wafer to be mounted. Even in such a case, the entire side peripheral surface can be covered in a close contact state. Then, the mounting table 7 is taken out of the thermostatic bath and installed in the vacuum chamber 1. In addition, if the heater for heating the said mounting base 7 is attached to the mounting base 7, and the temperature of a heater is raised and diameter reduction of a heat-shrinkable tube is performed, it is not necessary to use said thermostat.

  A heat-shrinkable tube made of PFA or FEP generally shrinks rapidly when heated at a temperature of 150 to 200 ° C., but can be shrunk even when heated at a temperature of 100 to 150 ° C. Therefore, even with a general electrostatic chuck layer 3 having a heat resistance of about 150 ° C. and an alumite coating or the like, the heat shrinkable tube is attached without causing damage to the electrostatic chuck layer 3. be able to.

  The covering member 71 thus provided is in close contact with the electrostatic chuck layer 3 and the support portion 21 so that the side peripheral surface of the bonding layer 70 is not exposed to the atmosphere in the processing chamber. The side peripheral surface of 70 may be in close contact, or there may be a gap.

  The heat-shrinkable tube described above is not limited to a fluororesin, and silicone rubber, polyolefin, or the like may be used. When a material other than fluororesin is used as the heat shrinkable tube, it is desirable to coat the surface of the heat shrinkable tube with fluorine in order to prevent deterioration of the material due to active species, for example, deterioration of the resin.

  Here, an example of a method for coating the substrate with fluorine will be described. First, the surface of a base material (here, a heat-shrinkable tube) is roughened by blasting or the like as a base treatment, a primer is applied to the roughened surface, and is fired in a heating furnace. Finally, a fluorine coating material is applied to the surface, heated in a heating furnace, and fired. In this case, a desired fluorine coating layer may be formed on the surface of the substrate by repeating the last step a plurality of times.

  The support part 21, the bonding layer 70, and the electrostatic chuck layer 3 are coated with a fluorine coating material, heated in a heating furnace, and sintered, thereby supporting the part 21, the bonding layer 70, and the electrostatic chuck. A fluorine coating layer may be directly formed on the side peripheral surface of the layer 3.

  According to such an embodiment, the following operational effects are obtained. As described in the first embodiment, during the etching process, a processing gas such as C4F8 gas, NF3 gas, and SF6 gas is turned into plasma, and active species including fluorine radicals are generated. At this time, the active species group in the plasma enters between the wafer W and the ring body 6. However, since the covering member 71 is mounted in a state in which a contracting force is applied, that is, in a state in which a force tightened inward is applied. Since the electric chuck layer 3 and the support portion 21 are in close contact with each other, the contact between the active species and the side peripheral surface of the bonding layer 70 is prevented. For this reason, since the adhesive used for the bonding layer 70 is not eroded, the thermal conductivity of the bonding layer 70 does not change, and therefore the temperature rise of the outer peripheral portion of the wafer hardly occurs over time, and stable treatment over a long period of time. Thus, the life of the mounting table 7 can be extended. In particular, in the treatment using NF3 gas and SF6 gas, the fluorine radical concentration becomes high. Therefore, if the bonding layer 70 is a silicone rubber adhesive in the conventional structure, the erosion of the bonding layer is severe and the life is extremely short. On the other hand, according to the present embodiment, the life of the mounting table 7 can be greatly improved.

  Further, during the etching process, the electrostatic chuck layer 3 and the support base 21 are heated and expanded by the heat of plasma. Generally, a ceramic plate used for the electrostatic chuck layer 3 is a metal substrate used for the support base 21. For example, if the covering member 71 is made of a hard material, it cannot follow the thermal expansion of the electrostatic chuck layer 3 and the support base 21 and breaks brittlely, or a gap is formed. Will peel off. On the other hand, since the covering member 71 is flexible, the covering member 71 can follow the thermal expansion of the electrostatic chuck layer 3 and the support base 21, and is kept in a close contact state without fear of brittle fracture or peeling.

  The covering member 71 is not limited to a heat shrinkable tube, and may be an elastic body such as rubber or elastomer. If the elastic ring is mounted across the convex portion of the support portion 21 and each side peripheral surface of the electrostatic chuck layer 3 with the ring expanded, the restoring force of the ring is applied to these side peripheral surfaces. Since they are in close contact, the same effects as described above are exhibited. In this case, it is preferable to apply the above-described fluorine coating treatment to the elastic body. Moreover, you may give DLC (diamond like carbon) coating instead of a fluorine coating process. In addition, it is preferable to use a material in which the end of the heat shrinkable tube made of PFA is stabilized by fluorination treatment because fluorine ions are less likely to be generated during the reaction with active species or the like.

  Next, another example of the close contact structure of the covering member 71 will be briefly described with reference to FIG. 8A, the peripheral edge of the electrostatic chuck layer 3 protrudes outward from the bonding layer 70, and the lower surface of the protruding portion is formed as an inclined surface that is inclined so as to become lower toward the inner side. In addition, an O-ring having a circular cross-sectional shape is formed in the concave portion 73 formed by the inclined surface and the upper surface of the portion of the support portion 21 that protrudes outward from the bonding layer 70 and the bonding layer 70. It is the structure which fitted the coating | coated member 71 which consists of an elastomer ring body. With such a configuration, the covering member 71 contracts inward along the inclined surface of the electrostatic chuck layer 3 and is fitted in a state in which it is pressed against the contact surface of the recess 73 by its restoring force. Therefore, high adhesion can be obtained between the electrostatic chuck layer 3 and the support portion 21 and the covering member 71. FIG. 8B shows a covering made of, for example, an elastomer having a rectangular cross section on a groove 74 having a rectangular cross section formed by the lower surface of the protruding portion at the peripheral edge of the electrostatic chuck layer 3 and the support portion 21. A member 71 is inserted to protect the bonding layer 70.

  The bonding layer 70 used in the second embodiment may be a silicone adhesive resin or an acrylic adhesive resin. Other adhesive resins may be used.

  It should be noted that the surface portion of the mounting table prepared as a mounting table for mounting a wafer having an orientation flat using a heat shrinkable tube made of PFA, ie, a similar shape to the wafer shape having an orientation flat (static When the heat-shrinkable tube is brought into close contact with the surface portion of the electric chuck layer and the support portion as described above, the gap between the surface portion of the mounting table and the heat-shrinkable tube including the portion of the orientation flat is completely seen. It is confirmed that the contact is made without unevenness.

[Third Embodiment]
A third embodiment of the processing apparatus according to the present invention will be described. FIG. 9 is a longitudinal sectional view showing the entire structure of a plasma apparatus, which is a processing apparatus according to an embodiment of the present invention, applied to an etching apparatus. In the figure, reference numeral 120 denotes a process vessel made of a conductive member such as aluminum and formed hermetically, and the process vessel 120 is grounded. The processing vessel 120 also serves as an upper electrode 130 that also serves as a gas shower head that is a gas supply unit for introducing a predetermined processing gas, and a lower electrode that is used to place a wafer W that is a substrate to be treated. The mounting table 140 is provided so as to face each other. Further, an exhaust pipe 121 is connected to the bottom of the processing container 120, and a vacuum pump 122 such as a turbo molecular pump or a dry pump is connected to the exhaust pipe 121. Further, an opening 123 for loading / unloading the wafer W, which is provided with a gate valve 123a that can be freely opened and closed, is provided on the side wall of the processing container 120.

  A number of gas diffusion holes 132 communicating with the gas supply path 131 are formed on the lower surface side of the upper electrode 130, and a processing gas is supplied toward the wafer W placed on the mounting table 140. It is comprised so that. Further, the gas supply path 131 has a base end connected to a gas supply source 131b via a flow rate adjusting unit 131a. The upper electrode 130 is connected to a high frequency power supply unit 134 for supplying high frequency power having a frequency of 60 MHz, for example, via a low pass filter 133. Furthermore, a shield ring 135 made of annular quartz is provided around the upper electrode 130 so as to be fitted to the outer peripheral portion of the upper electrode 130.

  The mounting table 140 includes a columnar support portion (mounting table body) 150 made of a conductive member such as aluminum, and an electrostatic chuck layer 160 is provided on the surface of the support portion 150. As shown in FIG. 10, the electrostatic chuck layer 160 is configured by embedding a foil-like chuck electrode 162 in a ceramic plate 161 which is a dielectric plate made of a dielectric such as alumina (Al 2 O 3). The thickness of the ceramic plate 161 is, for example, 1 to 5 mm. As ceramics used here, in addition to alumina, for example, aluminum nitride (AlN), yttrium oxide (Y2O3), lead nitride (PbN), silicon carbide (SiC), titanium nitride (TiN), magnesium oxide (MgO), etc. Is used.

  A plurality of spacers 171 are interposed between the surface of the support portion 150 and the electrostatic chuck layer 160, and a bonding layer 172 is formed in the gap. The spacer 171 is, for example, a ceramic piece formed in a circular shape having a thickness of 0.01 to 0.1 mm and a diameter of 1 to 5 mm. For example, one piece is provided at the center of the support portion 150 as shown in FIG. A plurality are provided. As the ceramic piece, those listed as materials for the electrostatic chuck layer 160 can be used. For example, the same material as the ceramic plate 161 of the electrostatic chuck layer 160 is used. The height of the gap in which the spacer 171 and the bonding layer 172 are disposed (the separation distance between the electrostatic chuck layer 160 and the support portion 150) is, for example, 0.01 to 0.1 mm. The step of adhering the electrostatic chuck layer 160 onto the support part 150 includes first applying a thermosetting adhesive resin on the support part 150, embedding a spacer in the bonding layer 172, and placing a ceramic plate thereon. After pressing, the adhesive resin is cured by heating. After that, a step of grinding the surface of the ceramic plate 161 to obtain flatness is performed.

  Further, as the bonding layer 172, for example, a mixture obtained by mixing ceramic powder as a filler material with silicone-based adhesive resin or acrylic-based adhesive resin can be used. The constituent materials are selected so that the dielectric constants of the spacer 171 and the bonding layer 172 are equal. Equivalent here means that 0.90ε2 ≦ ε1 ≦ 1.10ε2 is established, where ε1 is the dielectric constant of the spacer 171 and ε2 is the dielectric constant of the bonding layer 172. For the purpose of the present invention, it is ideal that ε1 = ε2, but actually, in order to adjust the blending ratio of filler materials and the like so that the relative dielectric constants of the two are uniform, 10% between the two. There may be some degree of variation.

  As the ceramic powder used as the filler material, for example, the same kind as the ceramic piece constituting the spacer 171 can be used, but a different one may be used. Further, for example, ceramic powder having a relative dielectric constant higher than that of the spacer 171 is used, and this ceramic powder and an adhesive resin lower than the relative dielectric constant of the spacer 171 are mixed to have the same dielectric constant as that of the spacer 171. You may adjust so that it may become a dielectric constant. Furthermore, even if the same kind of ceramic, for example, alumina, has a different dielectric constant, when ceramic powder having a dielectric constant higher than that of the spacer 171 is used, the ceramic powder (filler) has a relative dielectric constant. High alumina may be used, and alumina having a low relative dielectric constant may be used as the spacer 171.

  The spacer 171 is not limited to a ceramic piece. However, using a ceramic piece made of a material having a large relative dielectric constant, for example, a material having a relative dielectric constant of 9.0 or more can increase the efficiency of high frequency, that is, etching. This is preferable in terms of increasing the rate.

  A DC power supply unit 164 is connected to the chuck electrode 162 of the electrostatic chuck layer 160 via a switch 163. When a DC voltage is applied to the chuck electrode 162, it is generated in the upper layer of the chuck electrode 162 in the ceramic plate 161. For example, the wafer W is electrostatically attracted by electrostatic attraction. Around the electrostatic chuck layer 160, a focus ring 165 is provided so as to surround the periphery of the wafer W attracted and held by the electrostatic chuck layer 160, and further, for example, a cover ring 166 made of quartz is provided.

  Further, a high frequency power supply unit 152 for applying a bias voltage having a frequency of 2 MHz, for example, is connected to the support unit 150 through a high pass filter 151. Furthermore, in the support portion 150, an inflow path 153 and an outflow path 154 are connected, and for example, a temperature adjustment fluid flow path 155 that forms a temperature adjustment means for allowing a temperature adjustment medium of 120 ° C. to flow therethrough is provided. This temperature adjusting means has a role of adjusting the temperature of the wafer W to a set temperature by absorbing the heat when the wafer W receives heat from the plasma. The mounting table 140 is configured to be movable up and down by an elevating mechanism 156 provided at the lower portion of the processing container 120, and the mounting table 140 has an elevating pin for transferring the wafer W to a transfer arm (not shown). Not shown). Reference numeral 157 denotes a bellows for preventing plasma from entering under the mounting table 140.

Next, the operation of the above etching processing apparatus will be described. First, the gate valve 123a is opened, and the wafer W on which a mask pattern made of a resist film is formed is loaded into the processing container 120 from a load lock chamber (not shown) and mounted on the electrostatic chuck layer 160 of the mounting table 140. After that, the gate valve 123a is closed to make the processing container 120 airtight. Then, while the inside of the processing vessel 120 is evacuated by the vacuum pump 122, the etching including a processing gas, for example, a halogenated carbon gas such as C ₄ F ₆ and C ₂ F ₆ , an oxygen gas, and an argon gas is performed via the gas supply pipe 131. A gas is introduced at a predetermined flow rate and uniformly injected toward the surface of the wafer W through the gas diffusion holes 132, and the inside of the processing container 120 is maintained at a vacuum level of, for example, several tens of mTorr. Then, the etching gas supplied into the processing container 120 flows radially outward along the surface of the wafer W and is uniformly exhausted from the periphery of the mounting table 140.

  Subsequently, for example, a high frequency voltage of 60 MHz, for example, is applied to the upper electrode 130 from the high frequency power supply unit 134 at, for example, 1800 W, and further, for example, at a timing of 1 second or less, A voltage is applied at 1850-2250W, for example. The high frequency from the high frequency power supply unit 134 reaches the wafer W, further passes through the electrostatic chuck layer 160, reaches the support unit 150 via the spacer 171 or the bonding layer 172, and flows to the ground by the high pass filter 151. On the other hand, the high frequency from the high frequency power supply unit 152 for bias reaches the electrostatic chuck layer 160 from the support unit 150 via the spacer 171 or the bonding layer 172 and further reaches the wafer W. As a result, the etching gas, which is the processing gas, is turned into plasma by the high frequency from the high frequency power supply unit 134, and the active species of this plasma is incident with high perpendicularity on the surface of the wafer W to which the high frequency bias is applied. The resist film is etched with a predetermined selectivity.

Here, FIG. 12 shows a high-frequency path (a vertical region including the spacer 171) Pa in the projection area of the spacer 171 and a high-frequency path Pb in the projection area of the bonding layer 172 having the same size as the projection area of the spacer 171. Is an equivalent circuit. Assuming that C1 is the electrostatic capacity of the spacer 171, C2 is the electrostatic capacity of the bonding layer 172, and C3 is the electrostatic capacity of the electrostatic chuck layer 160, the total static capacity of the electrostatic chuck layer 160 and the spacer 171 in the passage Pa. The capacitance Ca is expressed by the formula (1).
Ca = C1 · C3 / (C1 + C3)
= (Ε0 · ε1 / d) · (ε0 · ε3 / d3) · S / {(ε0 · ε1 / d) + (ε0 · ε3 / d3)} (1)
In addition, the total capacitance Cb of the electrostatic chuck layer 160 and the bonding layer 172 in the passage Pb is expressed by equation (2).

Cb = C2 / C3 / (C2 + C3)
= (Ε0 ・ ε2 / d) ・ (ε0 ・ ε3 / d3) ・ S / {(ε0 ・ ε2 / d) + (ε0 ・ ε3 / d3)} (2)
Where ε0 is the relative permittivity in vacuum, ε1 is the relative permittivity of the spacer 71, ε2 is the relative permittivity of the bonding layer 172, ε3 is the relative permittivity of the electrostatic chuck layer 160, and d is the thickness of the spacer 171 (bonding) The thickness of the layer 172), d3 is the thickness of the electrostatic chuck layer 160, and S is the cross-sectional area of the spacer 171.

  Since the impedances of the passages Pa and Pb with respect to the high frequency are expressed by 1 / ω · Ca and 1 / ω · Cb, respectively, if the relative dielectric constant ε 1 of the spacer 171 and the relative dielectric constant ε 2 of the bonding layer 172 are different from each other, Between Pa and Pb, the magnitude of the high-frequency power supplied from the high-frequency power supply unit 134 differs by an amount corresponding to the reciprocal of the values of the above equations (1) and (2), and the plasma state differs. However, if the values of ε1 and ε2 are made equal (equal values), the magnitude of the high frequency power becomes substantially the same, and the plasma state becomes the same. The same applies to the bias voltage supplied from the high frequency power supply unit 152 for bias. That is, when a bias voltage having a frequency much lower than the high frequency for generating plasma is applied to the wafer W, ions in the plasma try to be attracted to the surface of the wafer W, and the ions are incident on the surface of the wafer W with high perpendicularity. However, even in this case, since the collision energy of ions is uniform between both passages Pa and Pb, it contributes to the in-plane uniformity of etching.

  Therefore, according to the above-described embodiment, the etching rate (etching rate) is uniform between the region corresponding to the projection region of the spacer 171 and the region corresponding to the projection region of the bonding layer 172 on the surface of the wafer W. Actually, parameters such as gas flow rate and pressure are adjusted so that the etching rate is uniform between the central portion and the peripheral portion of the wafer W, but even in this case, the high frequency power between the above two regions is adjusted. If the efficiency is uniform, a high in-plane uniformity can be secured with respect to the etch rate as a result by adjusting parameters and the like, which is a significant technique for coping with the thinning of the device and the miniaturization of the pattern.

  As the spacer 171, instead of forming a small circular shape as described above, for example, as shown in FIG. 13, a circular spacer 171 is arranged at the center and the spacer 171 is surrounded on the outer side. A ring-shaped spacer 171 may be arranged.

  In addition, the plasma processing that is an object of the present invention is not limited to etching processing, and may be other processing such as film formation processing or ashing processing. Furthermore, the apparatus that is the subject of the present invention is not limited to the parallel plate type plasma processing described in the above embodiment, and for example, microwaves are introduced into a processing container through an antenna to generate plasma. The present invention can also be applied to a device that generates plasma using electron cyclotron resonance or a device that applies a high frequency bias to a mounting table.

  In order to confirm the effect of the present invention, an electrostatic chuck layer constituted by embedding a chuck electrode in an alumina plate is provided on the surface of a support portion made of aluminum with a spacer made of alumina pieces interposed in the layout shown in FIG. Adhesion was performed with a silicone-based adhesive resin. This adhesive resin was mixed with alumina powder as a filler material so as to have the same dielectric constant as that of the bonding layer and the spacer. The relative dielectric constant of the spacer was 9.5, and the relative dielectric constant of the bonding layer was adjusted to 9.0. When the wafer W on which the silicon oxide film is formed is mounted on the mounting table 140 configured as described above and the etching rate is examined under the process conditions described in the above embodiment, the in-plane uniformity of the etching rate is found. It was good.

  The third embodiment may have a configuration combined with the second embodiment described above. That is, in FIG. 10, the covering member 71 described in the second embodiment may be closely attached to the side peripheral surface of the bonding layer 172.

[Fourth Embodiment]
A fourth embodiment of the processing apparatus according to the present invention will be described. FIG. 14 is a longitudinal sectional view showing the entire structure of a plasma etching apparatus which is a processing apparatus according to the present invention.

  In the figure, reference numeral 210 denotes a vacuum chamber constituting the processing apparatus, which is formed so as to form an airtight structure with a conductive material such as aluminum, and the vacuum chamber 210 is grounded for safety. A substantially cylindrical deposition shield 212 is disposed on the inner surface of the vacuum chamber 210 to prevent the inner surface from being damaged by plasma. In the vacuum chamber 210, a gas shower head 214 that also serves as an upper electrode and a mounting table 216 that also serves as a lower electrode are provided to face each other, and a bottom surface is provided with, for example, a turbo molecular pump or a dry pump. An evacuation passage 218 communicating with the evacuation means (not shown) is formed.

  An opening 220 for loading and unloading the wafer W, which is a substrate to be processed, is formed on the side wall of the vacuum chamber 210, and can be opened and closed by a shutter 222 that moves up and down by an air cylinder or the like. The gas shower head 214 includes a high frequency plate 214a, a cooling plate 214b, and an electrode plate 214c. A high frequency power source 226 is connected to the high frequency plate 214a via a matching unit 224, and for example, high frequency power of 13.56 MHz to 100 MHz is applied.

  A medium circulation path 228 is provided inside the high-frequency plate 214a, and the cooling plate 214b and the electrode plate 214c disposed in contact with the high-frequency plate 214a are set to desired temperatures by activating a temperature adjusting unit (not shown). can do. The temperature adjusting means has an introduction pipe 230 for circulating the refrigerant through the medium circulation path 228, and the refrigerant adjusted to an appropriate temperature is supplied into the medium circulation path 228 by the introduction pipe 230, and the heat The exchanged refrigerant is discharged to the outside through a discharge pipe (not shown). The medium circulation path 228 may be provided on the cooling plate 214b. Thereby, the electrode plate 214c can be cooled more positively, which is preferable.

  A gas supply means 232 is connected to the gas shower head 214, and a process gas whose flow rate or pressure is controlled is supplied into the vacuum chamber 210 through a gas supply pipe 234 connected to a gas source (not shown). A plurality of gas supply paths and gas holes 236 are formed in the cooling plate 214b and the electrode plate 214c so as to correspond to the size of the wafer W on the mounting table 216, and the process gas from the gas supply means 232 is supplied to the cooling plate 214b and the electrode plate 214c. It is configured to supply uniformly to the surface of the wafer W through the gas supply path and the gas holes 236.

  The mounting table 216 is provided below the gas shower head 214 at an interval of about 5 to 150 mm. For example, an electrode main body 244 made of aluminum whose surface is anodized and the electrode main body 244 are placed in a vacuum chamber. And an insulator 238 for insulating from 210. The electrode main body 244 has an electrostatic attraction mechanism for attracting and holding the wafer W, and a high-frequency power source 242 is connected via the matching unit 240. Then, for example, high-frequency power of 800 kHz to 3.2 MHz is applied to the electrode body 244 from the high-frequency power source 242.

  An annular focus ring 246 is disposed around the electrode body 244, and an insulating or conductive material is selected depending on the process and acts to confine or diffuse reactive ions. To do. Further, an insulator 248 is formed outside the focus ring 246. The insulator 248 is made of an insulating material as a whole or is covered with an insulating film on a conductive material surface.

  Further, an exhaust ring 250 in which a plurality of exhaust holes are formed surrounds the mounting table 216 at a position below the surface (mounting surface) of the mounting table 216 between the mounting table 216 and the side wall of the vacuum chamber 210. Are arranged as follows. The exhaust ring 250 regulates the flow of the exhaust flow and optimally confines plasma between the mounting table 216 and the gas shower head 214. Further, inside the mounting table 216, a plurality of elevating pins 252 that are elevating members for transferring the wafer W to and from a transfer arm (not shown) can be projected and retracted, for example, three (only two are shown). The raising / lowering pin 252 is provided so as to be raised and lowered by a driving mechanism (not shown).

  Next, with reference to a schematic cross-sectional view schematically showing the electrode main body 244 shown in FIG. 15, the main part of the present embodiment will be described in detail.

  As shown in FIG. 15, the electrode main body 244 includes an electrostatic adsorption unit (electrostatic adsorption device) 254 and a high-frequency plate 256, and the high-frequency plate 256 is provided with the high-frequency power source 242 as described above. And high frequency power of 800 kHz to 3.2 MHz is applied. In this embodiment, a medium circulation path 258 is formed in the high-frequency plate 256, and a medium whose temperature is adjusted is supplied to the medium circulation path 258 from a medium supply means (not shown) via the supply path 260. .

The electrostatic attraction unit 254 provided on the high-frequency plate 256 includes a dielectric 254a, an adsorption electrode 254b included therein, and a ferromagnetic body 254c provided on the back side of the adsorption electrode 254b. That is, in the present embodiment, the electrostatic attraction unit 254 and the ferromagnetic body 254c are integrally configured. The dielectric 254a is made of a sintered or spray-formed ceramic, and is selected from materials such as aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN). Further, by adding titanium dioxide (TiO ₂ ), silicon carbide (SiC) or the like to these materials and adjusting the volume specific resistance value or the dielectric constant, a desired adsorption force can be obtained.

  The adsorption electrode 254b is disposed in the vicinity of the surface layer of the electrode main body 244, and is formed in a foil shape from, for example, tungsten. The adsorption electrode 254b is configured to be switched and connected between the DC power supply 262 and the ground via the switch unit SW1. Then, an electrostatic adsorption force is generated between the dielectric 254a and the wafer W by applying a DC voltage to the adsorption electrode 254b.

  The ferromagnetic body 254c is provided in contact with or close to the back side of the adsorption electrode 254b. The material of the ferromagnet 254c is selected according to the process performed in the vacuum chamber 210. Specifically, a material having a Curie point at a temperature to be controlled is selected. For example, when the wafer W is to be heated to 110 to 120 ° C., Mn—Zn ferrite, Ni—Zn ferrite, or the like is selected.

  The ferromagnetic material 254c can be formed on the adsorption electrode 254b or the dielectric 254a by a known coating method or thermal spraying method after the ferromagnetic material is melted in a solvent. Further, a ferromagnetic material may be formed into a plate shape by a sintering method and bonded to the dielectric 254a with an adhesive or the like, or the ferromagnetic material may be made into particles and added to the dielectric 254a. May be. Further, when the dielectric 254a is made of a porous material, the pores of the dielectric 254a can be filled with a ferromagnetic material 254c melted in a solvent. Thus, it is preferable to select a method of forming the ferromagnetic body 254c according to the material of the ferromagnetic body, the usage environment, and the like.

  Next, a processing operation in the plasma etching apparatus configured as described above will be described.

  First, the wafer W is loaded into the vacuum chamber 210 through the opening 220 and the shutter 222, the wafer W is placed on the mounting table 216, and the shutter 222 is closed. Accordingly, the inside of the vacuum chamber 210 is exhausted to a predetermined degree of vacuum. Then, a process gas is supplied into the vacuum chamber 210 and a DC voltage is applied to the adsorption electrode 254b from the DC power source 262 to electrostatically adsorb the wafer W onto the surface of the mounting table 216.

  Next, high-frequency power of a predetermined frequency is applied from the high-frequency power sources 226 and 242 in this state. As a result, a high-frequency electric field is generated between the gas shower head 214 and the mounting table 216, the process gas is turned into plasma, and the wafer W on the mounting table 216 is etched. Since the ferromagnetic material 254c having a Curie point at the temperature to be controlled is provided inside the mounting table 216, high-frequency power is applied to the high-frequency plates 214a and 256, thereby causing eddy current loss caused by dielectric action. The ferromagnetic body 254c generates heat.

  That is, when a high frequency current passes through the inside of the ferromagnetic body 254c, a magnetic force line (magnetic field) due to the high frequency current is generated on the surface of the ferromagnetic body 254c, and an eddy current is generated so as to cancel the magnetic field line. Due to the resistance heat caused by the eddy current, the ferromagnetic body 254c generates heat near the surface.

  Due to this heat generation, the temperature of the ferromagnetic body 254c rises, and when the temperature exceeds the Curie point, it becomes a paramagnetic body and does not generate heat, and is maintained at a constant temperature. Then, if necessary, the temperature of the wafer W on the mounting table 216 can be controlled with high accuracy by controlling the flow rate and temperature of the refrigerant circulated through the medium circulation path 258.

  The ferromagnetic body 254c is preferably set to a thickness slightly larger than twice the skin depth (SKIN DEPTH). Skin depth is used as a measure of the depth at which current flows, and is expressed by the following equation (3).

Skin depth δ = (2ρ / ωμ) ^1/2 (3)
Where ρ: resistivity, ω: 2πf {f is frequency}, μ: μ ₀ (1 + χ) {μ ₀ : vacuum transmittance, χ: magnetic susceptibility}
As described above, according to the present embodiment, since the electrode to which high-frequency power is applied has the ferromagnetic body 254c, the temperature of the ferromagnetic body 254c can be controlled to the Curie point of the material. The electrodes in the vacuum chamber 210 can be heated and controlled with a very simple configuration without providing a conventional heating mechanism. And since the ferromagnetic body 254c stops heat_generation | fever correctly at the Curie point temperature intrinsic | native to the material, the heat input can be grasped | ascertained and the wafer W can be temperature-controlled accurately.

  Next, an embodiment in which the above-described configuration for temperature control is applied to a gas shower head that functions as an upper electrode will be described. FIG. 16 is a schematic cross-sectional view schematically showing a gas shower head 214 ′ applied to such an embodiment. Like the embodiment of FIG. 15, a ferromagnetic material having a certain Curie point is shown. The gas shower head 214 ′ is heated by being disposed in the electrode, that is, in the gas shower head 214 ′.

  As shown in FIG. 16, the gas shower head 214 ′ has a high frequency plate 214a, a cooling plate 214b, and an electrode plate 214c from the top, as well as the gas shower head 214 of FIG. The ferromagnet 264 is in contact with or in close proximity to. The ferromagnetic body 264 is provided with a hole that communicates with the gas supply path and the gas hole 236. As in the embodiment of FIG. 15, the ferromagnetic material 264 may be formed in a film shape on the lower surface side of the electrode plate 214c using a known coating method or thermal spraying method, or may be formed into a plate shape by a sintering method. It may be formed and adhered to the surface of the electrode plate 214c, or the ferromagnetic material may be powdered and added to the electrode plate 214c. At least the surface of the ferromagnetic material 264 is covered with an insulating film 266 such as ceramic or resin.

  When high frequency power is applied to the high frequency plate 214a, the ferromagnetic material 264 generates heat up to the Curie point. As described above, when the temperature exceeds the Curie point, it becomes a paramagnetic material and does not generate heat. The body 264 is maintained at the temperature of the Curie point. Then, by monitoring the temperature of the gas shower head 214 ′ and circulating the refrigerant whose temperature is adjusted in the medium circulation path 228, the gas shower head 214 ′ can be accurately controlled to a desired temperature.

  In the embodiment of FIG. 15, the apparatus in which the ferromagnetic body 254c is arranged in the electrostatic adsorption layer 254 has been described. For example, the high-frequency plate 256 to which high-frequency power is applied is made of a ferromagnetic body. Also good. Similarly, in the embodiment shown in FIG. 16, the ferromagnetic body 264 is provided in contact with or close to the electrode plate 214c, but the high-frequency plate 214a itself may be made of a ferromagnetic material.

  Furthermore, in the above-described embodiment, the case where the lower electrode holding the wafer W and the corresponding upper electrode are arranged in parallel in the vertical direction has been described as an example. The invention can also be applied to, for example, a processing apparatus in which two electrodes are spaced apart in the horizontal direction. The present invention can also be applied to a processing apparatus that applies high-frequency power only to the upper electrode or only the lower electrode, or a processing apparatus that applies high-frequency power to both the upper electrode and the lower electrode.

  Moreover, in the said embodiment, although demonstrated taking the parallel plate type plasma etching apparatus as an example, this invention is not limited to this structure. The present invention can also be applied to various plasma processing apparatuses such as a magnetron type and an inductively coupled type. Further, the present invention can be applied not only to a plasma etching process but also to various processing apparatuses such as an ashing process and a film forming process. The present invention can also be applied to an apparatus for processing a glass substrate for LCD.

  According to such an embodiment, since the electrode having the high frequency plate to which the high frequency power is applied has the heating element made of the ferromagnetic material, the temperature of the heating element is set to the Curie point of the material. It is possible to control the heating of the electrode with a very simple configuration without providing a conventional heating mechanism. And since the ferromagnetic material which comprises a heat generating body stops heat_generation | fever correctly at the Curie point temperature intrinsic | native to the material, it can grasp | ascertain the amount of heat inputs and can temperature-control a to-be-processed object accurately.

It is a longitudinal cross-sectional view which shows the whole structure of an example of the processing apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the mounting base provided in the said processing apparatus. It is process drawing which shows the manufacturing method of the joining layer provided in the mounting table mentioned above. It is process drawing which shows the manufacturing method of the mounting table mentioned above. It is a characteristic view for demonstrating the effect in the 1st Embodiment of this invention. It is sectional drawing which shows the mounting base in the 2nd Embodiment of this invention. It is explanatory drawing which shows the installation method of the coating | coated member provided in the said mounting table. It is explanatory drawing explaining the specific form of the coating | coated member. It is a longitudinal cross-sectional view of the plasma processing apparatus which concerns on the 3rd Embodiment of this invention. It is explanatory drawing which shows typically the mounting base with which said plasma processing apparatus is provided. It is a top view which shows an example of the arrangement layout of the spacer on a support part. It is explanatory drawing which shows the equivalent circuit of the high frequency path | route from a wafer to a support part. It is a top view which shows the other example of the arrangement layout of the spacer on a support part. It is a longitudinal cross-sectional view which shows the plasma etching apparatus which concerns on the 4th Embodiment of this invention. It is a schematic sectional drawing which shows typically the electrode main body which comprises the mounting base of the plasma etching apparatus shown in FIG. It is a schematic sectional drawing which shows typically the gas shower head of the plasma etching apparatus which concerns on the 4th Embodiment of this invention. It is a longitudinal cross-sectional view which shows the processing apparatus concerning a prior art. It is a longitudinal cross-sectional view which shows the mounting base of the processing apparatus which concerns on the prior art.

Explanation of symbols

W wafer 1 vacuum chamber 11 upper electrode 2 mounting table 25 high frequency power supply 3 electrostatic chuck layer 31 chuck electrode 4 bonding layer 5 protective layer 6 ring member 7 mounting table 70 bonding layer 71 coating member 72 sprayed film 73 space 74 groove part

Claims (7)

A processing container for performing plasma processing on the substrate;
An electrostatic chuck layer that is provided in the processing container and that covers the chuck electrode with an insulating layer for holding the substrate by the electrostatic adsorption force by applying a voltage to the chuck electrode;
A support portion made of a material different from that of the electrostatic chuck layer for supporting the electrostatic chuck layer;
A bonding layer provided for bonding the support portion and the electrostatic chuck layer between the support portion and the electrostatic chuck layer;
A processing apparatus comprising: a flexible heat shrinkable tube provided to cover a side peripheral surface of the bonding layer in order to protect the bonding layer from active species generated by plasma. The processing apparatus according to claim 1 , wherein the heat shrinkable tube is made of a fluororesin. The processing apparatus according to claim 2 , wherein the fluororesin is PFA, FEP, or PTFE. The processing apparatus according to claim 1 , wherein the covering member is coated with fluorine. High frequency power is supplied to the support to generate plasma,
Between the electrostatic chuck layer and the support portion, the processing apparatus according to claim 1, wherein the spacer relative dielectric constant is equivalent to the dielectric constant of the bonding layer is characterized by being interposed. 6. The processing apparatus according to claim 5 , wherein the spacer is a ceramic piece, and the bonding layer is a mixture of an adhesive resin and ceramic powder as a filler material. The bonding layer, the processing apparatus according to any one of claims 1 to 6, characterized in that a silicone-based adhesive resin or an acrylic adhesive resin.

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