JP3913643B2 - Wafer processing apparatus and wafer stage - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to semiconductor manufacturing technology. In particular, the present invention relates to a processing apparatus for processing a wafer at a high temperature and a wafer stage provided in the processing apparatus.
[0002]
[Prior art]
Known examples (patent publication or literature)
"Japanese Patent Laid-Open No. 11-87245"
Ruthenium, its oxide, platinum and the like are promising candidates for materials used for capacitor electrodes of next-generation semiconductor devices because of their compatibility with capacitor dielectric films having a high dielectric constant. In addition, zirconium oxide, hafnium oxide, etc. have been studied as gate insulating films in place of silicon oxide, and PZT (compound of platinum, zirconium, and titanium), BST (compound of barium, strontium, and titanium) have been studied as capacitor films. Yes. In this way, it is considered to use various new materials in the future semiconductor devices, but these new materials are thermally and chemically stable, extremely low in volatility, and are called non-volatile materials. Yes.
[0003]
In etching processing of these nonvolatile materials, it is essential to keep the temperature of the wafer being processed at a high temperature. That is, in the conventional etching processing apparatus, the temperature of the wafer is generally from a low temperature of about −50 ° C. to about 100 ° C. However, at such a temperature, the wafer is not etched because it is chemically very stable. Non-volatile materials need to be processed at a high temperature of 200 ° C. to 500 ° C.
[0004]
Therefore, recently, a processing apparatus capable of processing a wafer at a high temperature has become necessary, and in order to realize such a processing apparatus, not only the wafer can be heated to a high temperature but also when there is heat input from plasma. There is a need for a wafer stage that can control the temperature with high responsiveness without deteriorating the temperature distribution of the wafer.
[0005]
A method for managing the temperature of the wafer being processed to a high temperature with good controllability is disclosed in Japanese Patent Laid-Open No. 11-87245. In this example, a substrate holder for holding a wafer joins a plurality of blocks made of the same or different kinds of metal including a heating block containing a heater for heating the wafer with diffusion bonding with good thermal conductivity and confidentiality.
[0006]
[Problems to be solved by the invention]
However, in the disclosed example of “Japanese Patent Laid-Open No. 11-87245”, the electrostatic adsorption block that holds the wafer, the heat conducting block, the heating block, and the cooling block are integrated by diffusion bonding. Although it is small and excellent in controllability, for example, when the electrostatic chuck block reaches the end of its life and needs to be replaced, it is necessary to replace the entire substrate holder, and there is a problem that the work becomes large and the replacement cost is high.
[0007]
In addition, since the heat from the heater flows directly into the cooling block, there is also a problem that the power supplied to the heater during operation at a high temperature is large.
[0008]
Furthermore, the heat distribution due to radiation that affects the temperature distribution of the wafer being processed is not taken into account, and thus the temperature distribution of the wafer tends to deteriorate. Even in the embodiment, the heater is divided into the center and the outer periphery in order to improve the distribution. A method for supplying power independently is disclosed. However, in this case, there is a problem that the cost of the apparatus increases.
[0009]
An object of the present invention is to maintain a uniform temperature distribution of a wafer in a wide temperature range from 200 ° C. to about 500 ° C., and to remove the heat input to the wafer when processing with plasma. It is an object to provide a wafer stage and a wafer processing apparatus that can suppress a temperature rise.
[0010]
[Means for Solving the Problems]
The above object is a wafer processing apparatus for processing a semiconductor wafer held on a wafer stage disposed in a vacuum chamber whose inside is evacuated by using plasma formed in the vacuum chamber. The stage is placed with a metal cooling jacket in which a flow path for refrigerant flows is placed, and placed above the cooling jacket at a predetermined distance from the upper surface of the cooling jacket, and high-frequency power is supplied to the inside. and ceramic plate-like member and the electrode and the heater is arranged to be, a spacer for forming a space at a the distance between the cooling jacket top the plate-like member is placed on the said cooling jacket And a hole for supplying heat transfer gas between the wafer and the back surface of the wafer in a state where the wafer is held in a state where the wafer is held, Wherein the serial space communicates with the vacuum chamber, heat transfer between the plate-like member and the cooling jacket by radiation heat transfer through the space is achieved by being carried out.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
1 and 2 show a first embodiment of the present invention. FIG. 1 is an example in which the wafer stage of the present invention is actually applied to a plasma processing apparatus, and FIG. 2 is an enlarged view of the wafer stage of the present invention.
[0013]
As shown in FIG. 1, an etching gas 11 is introduced into the vacuum chamber 9, and the inside of the chamber is maintained at an appropriate pressure by adjusting the opening of a valve 12 installed upstream of the turbo molecular pump 13. A bell jar 10 made of alumina is loaded on the top of the vacuum chamber, and a coil 7 is installed around the bell jar. The coil 7 is connected to a high frequency power source 8 and a high frequency voltage, for example, 13.56 MHz, is applied to both ends of the coil to generate inductively coupled plasma 6. A plurality of fans 27 are attached around the bell jar, and the temperature of the bell jar is kept constant (about 70 ° C. to 120 ° C.). Etching is performed by exposing the wafer 1 to this plasma. During processing, the wafer is loaded on the wafer stage 2 and the temperature is controlled.
[0014]
A high frequency power source 5 is connected to the wafer stage in order to apply a bias voltage to the wafer. A DC power supply 22 is connected to the high-frequency voltage power supply line 19 in order to give an electrostatic chuck function to the wafer stage. In the figure, the other numbers, 3 is a flow controller for controlling the flow rate of the etching gas, and 4 is a gate valve, which is opened when the wafer is transferred, and allows the transfer arm (not shown) to move forward and backward.
[0015]
In this embodiment, the space is constituted by a gap 37 formed on the surface of the cooling jacket 14 facing the ceramic plate 15 in a state where the cooling jacket 14 and the ceramic plate 15 are attached to form a layer structure. Further, the cooling jacket 14 and the ceramic plate 15 have a configuration in which a zirconia spacer 23 is sandwiched between the cooling jacket 14 and the ceramic plate 15 and the zirconia bolts 36 are fixed between them. The distance formed by the space formed by the gap 37 needs to be adjusted precisely in order to adjust the temperature of the wafer stage 2 with good responsiveness or to reproduce it with high accuracy. The shape of is important.
[0016]
In the cooling jacket 14 of the present embodiment, the projection provided around the hole connected to a through hole 29 (described later) provided in the central portion of the cooling jacket 14 in a state where it is combined with the ceramic plate 15 has a ceramic plate 15. The spacer 23 contacts the upper surface of the cooling jacket 14 and the lower surface of the ceramic plate 15 at the outer periphery of the cooling jacket 14. The convex portion is provided with a seal member for maintaining a hole continuous with the through hole 29 in an airtight manner with the gap 37. Further, the space formed by the gap 37 is evacuated and depressurized in the vacuum chamber 9 for processing, and the vacuum chamber 9 is maintained at the same high degree of vacuum while being maintained at a high degree of vacuum. A communication path (not shown) communicating with the inner space is provided. In this way, heat transfer due to radiation between the cooling jacket 14 and the ceramic plate 15 is suppressed by the fluid in the space, or the cooling jacket 14 and the ceramic plate 15 are more than necessary through the fluid in the space. It suppresses the transmission of heat. Further, the air may be exhausted by exhaust means that is in direct communication with the space defined by the gap 37. When the amount of heat conduction is increased, a fluid for heat conduction may be allowed to flow through this space and discharged as necessary.
[0017]
The reason why the material of the bolt for fixing the ceramic plate is zirconia is that the thermal conductivity is as low as about 3 W / mK, and the fracture toughness value is large and the mechanical strength is excellent. is there. Accordingly, there is an advantage that the amount of heat that escapes to the cooling jacket via the bolt can be suppressed, and the temperature distribution of the wafer can be prevented from being locally deteriorated. However, it is not necessarily limited to zirconia, and other ceramic bolts or metallic bolts can be used as long as they can achieve the required performance.
[0018]
The material of the ceramic plate 15 is aluminum nitride having a high thermal conductivity, and a heater 16 is embedded therein. Therefore, the ceramic plate can be heated by supplying electric power to the heater 16. The reason why the ceramic plate is made of aluminum nitride is that since the thermal conductivity is high, it is difficult to cause a temperature difference in the surface and the temperature distribution of the wafer can be prevented from deteriorating. However, it is not always necessary to use aluminum nitride, and other materials may be used.
[0019]
An internal electrode 17 for embedding an electrostatic chuck function and an RF bias on the wafer stage is embedded on the heater inside the ceramic plate. When a DC voltage is applied to the internal electrode, a potential difference is generated between the internal electrode and the wafer 1 (the wafer is exposed to plasma and is almost at ground potential), and electric charges are stored between the internal electrode and the back surface of the wafer. The wafer is fixed to the ceramic plate by suction. In addition to the DC voltage, a high-frequency voltage for applying bias power to the wafer is applied to the internal electrode. The high frequency power source 5 of FIG. 1 plays this role. In terms of electric circuit, a DC power supply 22 for electrostatic chuck is connected to the power supply line 19 via a coil 21. In this embodiment, the hollow shaft 20 provided in the support member corresponds to the power supply line. If a high frequency voltage is applied to the internal electrode, a bias voltage can be applied to the wafer, so that ions in the plasma can be effectively drawn, and the etching rate is increased and the etching shape is improved. You can expect.
[0020]
55 is a sheath thermocouple for measuring the temperature of the ceramic plate. A through hole 54 is provided in a part of the cooling jacket, and a recess 53 is provided on the back surface of the ceramic plate corresponding to the through hole position. The sheath thermocouple 55 is inserted so that the tip comes into contact with the bottom surface of the recess. Since the temperature to be measured changes when the contact state of the tip changes, in this embodiment, a sheath 56 is provided on the thermocouple, and a coil spring 57 is placed on the sheath, and the whole is fixed to the cooling jacket by the presser 58. is doing. Therefore, even if the attachment state of the ceramic plate changes somewhat, the contact pressure between the tip of the sheath thermocouple and the ceramic plate is always substantially constant, and a temperature measurement method with good reproducibility can be provided. The power supplied to the heater is controlled based on this temperature information.
[0021]
Electric power is supplied to the heater through a through hole 39 provided in the cooling jacket 14. A socket 41 that is electrically connected to the heater is built in the ceramic plate, and an electrical plug 42 that is connected to an external power source is disposed in this socket. In the present embodiment, only one heater power supply unit is described, but in actuality, connectors having opposite polarities are necessary, so there are two power supply units.
[0022]
Reference numeral 38 denotes a radiation heat insulating material for reducing heat escape from the outer periphery of the ceramic plate. The surface is chrome plated. If a radiation heat insulating material is provided, the radiation heat to the inner wall of the vacuum chamber can be suppressed to less than half, and the in-plane temperature distribution of the wafer stage can be prevented from deteriorating.
[0023]
Also, in order to effectively transfer the heat incident on the wafer being processed to the wafer stage and improve the controllability of the wafer temperature, it is necessary to introduce a heat transfer gas such as helium gas between the wafer back surface and the ceramic plate. is there. In this embodiment, the internal electrode is supplied through a hollow shaft built in a support member that applies a high frequency voltage and a direct current voltage. That is, helium gas is introduced into the back surface of the wafer from a through hole 29 provided at the center of the ceramic plate.
[0024]
A groove 46 for circulating the refrigerant is provided inside the cooling jacket. In this embodiment, the coolant uses cooling water installed in a clean room. The flexible piping 30 is used for pouring and draining the cooling water into the groove. This is because the entire wafer stage moves up and down as described later. In the figure, only the inlet of the cooling water is shown, and the return side is omitted. In the present embodiment, water is used as the refrigerant, but it is not necessarily limited to water. For example, it is possible to use a fluorocarbon refrigerant such as Fluorinert or Galden. However, when water is used, the heat transfer rate between the parts that circulate the refrigerant (in this example, the cooling jacket) is large, so the amount of heat transfer between the ceramic plates when the pressure between the gaps is the same. There is a merit that can be taken greatly. Conversely, the pressure required to secure the same amount of heat transfer is low. This is a great advantage in designing the apparatus because the sealing conditions for helium are relaxed.
[0025]
The wafer is transferred by moving the wafer stage 2 up and down by an expansion / contraction operation of the bellows 35 by an up / down mechanism (not shown), and peeling the wafer with the fixed pusher pins 32.
[0026]
When the wafer is processed by applying a bias voltage in this way, the temperature of the wafer rises due to heat input from the plasma. If the amount of heat input is small, it may not be a problem. However, in the semiconductor manufacturing process, the etching characteristics deteriorate if the wafer temperature is not properly controlled. Therefore, in order to keep the temperature of the wafer high, the ceramic plate is heated by the heater when there is no heat input from the plasma, and the electric power supplied to the heater is supplied when the processing starts and there is heat input from the plasma. It is necessary to reduce the heat incident on the wafer. As a method for this, in this embodiment, heat exchange is performed between the ceramic plate and the cooling jacket by radiant heat transfer. First, the heat balance of the Example which becomes the basis of the idea of a present Example is demonstrated based on FIG.
[0027]
In FIG. 3, 28 is the output of the heater, 31 is the radiant heat transfer to the cooling jacket, and 33 is the radiant heat transfer to the bell jar which is the opposite surface of the wafer stage. Although there is heat conduction through a zirconia screw for fixing the wafer stage to the cooling jacket, as described above, the heat transfer coefficient is small and can be ignored in this embodiment, so it is omitted here. The heat input from the plasma being processed is 34. First, in order to hold the wafer at a high temperature such as 200 ° C. to 500 ° C., it is necessary to heat the wafer stage from 200 ° C. to 500 ° C. In this case, it is necessary to satisfy the expression (1) in the steady state.
Heater output = radiant heat transfer to the cooling jacket + radiant heat transfer to the bell jar (1)
[0028]
On the other hand, when there is heat input to the wafer stage during plasma processing, it is necessary to satisfy the equation (2) in order to keep the temperature of the wafer stage constant.
Heater output + plasma heat input =
Radiant heat transfer to the cooling jacket + radiant heat transfer to the bell jar (2)
[0029]
That is, the temperature of the wafer stage can be kept constant by operating with the heater output of (1) before the start of processing and reducing the heater output by the amount of plasma heat input after the start of processing. In other words, if the amount of plasma heat input is greater than the amount of radiant heat transferred to the cooling jacket and bell jar, it means that even if the heater power is 0 W, the wafer temperature rises and cannot be controlled. FIG. 4 shows the calculation result of the heat balance of this example. From this figure, it can be seen that when operating at 400 ° C., the heater output without plasma heat input is 501 W, so that the allowable plasma heat input is 501 W. In the case of 300 ° C. and 200 ° C., the amount of heat transfer due to radiation is reduced, so that it becomes 246 W and 101 W, respectively.
[0030]
Therefore, according to the present embodiment, the wafer stage is fixed to the cooling jacket with zirconia bolts, and heat is exchanged with the cooling jacket and the bell jar by radiant heat transfer. Therefore, if the heat input to the wafer is 101 W or less, the structure is simple. Thus, a wafer stage capable of realizing a uniform temperature distribution over a wide temperature range at a high temperature of 200 to 400 ° C. can be supplied.
[0031]
Next, a method for increasing the heat input to the controllable wafer more than the above example will be described. In the first embodiment, the material of the cooling jacket was stainless steel, and the surface facing the ceramic plate was simply a machined surface. The emissivity of the surface was 0.3. The emissivity can be measured by a direct method in which the sample is heated to measure the emissivity, or by an indirect method in which calculation is performed based on the spectral reflectance obtained by measuring the reflection spectrum using FTIR. If the surface is coated with a black paint for the purpose of increasing this emissivity and increasing the amount of radiant heat transfer to the cooling jacket, the amount of radiant heat transfer of the ceramic plate can be increased. FIG. 5 shows the heat balance when the emissivity is 0.9. From this figure, it can be seen that when the temperature of the ceramic plate is 400 ° C., 300 ° C., and 200 ° C., the power that can be applied is increased to 818 W, 403 W, and 157 W.
[0032]
In addition, a method of increasing the surface area by providing irregularities on the surface of the cooling jacket, and a method of forming black alumite when the material of the cooling jacket is aluminum are also conceivable. However, what is important is to increase the emissivity of the surface of the cooling jacket, and means for doing so do not limit the scope of the invention.
[0033]
FIG. 6 shows a second embodiment of the present invention.
In this embodiment, the ring-shaped heat conducting member 24 using Inconel is adjusted so that the temperature of the wafer 1 can be adjusted even if the amount of heat input to the wafer 1 is increased as compared with the first embodiment. The structure is sandwiched between a ceramic plate and a cooling jacket. The cooling jacket is provided with a groove 25 for positioning the heat conducting member as shown in FIG. FIG. 8 is a perspective view of the heat conducting member, and FIG. 9 is a sectional view thereof.
[0034]
The heat conductive member of the present embodiment has a height larger than the height of the spacer 23 in a state before being attached, assuming that the vertical direction in FIGS. Thereby, in a state where the ceramic plate 15 and the cooling jacket 14 are attached, the upper end of the ceramic plate 15 and the lower end of the ceramic plate 15 and the cooling jacket 14 are in contact with each other. Further, when the ceramic plate 15 and the cooling jacket 14 are attached or removed, an elastic portion is provided which can be elastically expanded and contracted, and the force due to the expansion and contraction of the elastic portion causes the ceramic plate 15 and the cooling plate to cool the upper and lower ends. It is pressed against the jacket 14 for good contact and keeps the heat conduction resistance low. This elastic portion is connected so that heat conduction with the end portion is good, and in particular, in this embodiment, the elastic portion is integrally formed of the same member.
[0035]
Further, the elastic member is configured by bending or bending a plate material having a thickness sufficient to exhibit elasticity in a direction crossing the extending and contracting direction of the end portion. With such a configuration, when the ceramic plate is disposed in the groove of the cooling jacket and fixed to the cooling jacket, both ends of the heat conductive member come into contact with the ceramic plate and the cooling jacket with good reproducibility due to the elasticity in the thickness direction of the heat conducting member.
[0036]
In this embodiment, the cross-sectional shape of the heat conducting member is W-shaped as shown in FIG. 9, but other U-shaped and C-shaped cross-sectional shapes are also conceivable, but the height (thickness) is important. ) In the direction of elasticity. Since the purpose of the heat conducting member is to control the amount of heat transfer from the ceramic plate to the cooling jacket, the material characteristics are heat resistance, easy to process into thin walls, and the elasticity in the thickness direction after processing into thin walls is It is conceivable that the heat transfer amount expected by the heat resistance of the heat conducting member after processing can be ensured and the cost is low. Inconel is adopted as a material satisfying these conditions in this embodiment, but stainless steel is considered as a candidate.
[0037]
When there is elasticity in this way, reproducibility of the contact state of both ends of the heat conducting member is ensured, and the thermal resistance is determined by the length in the thickness direction and the thickness. However, in actual application, it is necessary to clarify by experiment. An estimate is made by calculation of the heat conducting member of this embodiment. Inconel has a thermal conductivity of 12 W / mK, a thickness of 0.3 mm, a length in the thickness direction of 16 mm, a diameter of 210 mm, and a thermal resistance of 6.7 K / W. When actually evaluated, the thermal resistance is 6.4 K / W, and it can be seen that they almost coincide. This indicates that the contact thermal resistance is so small as to be negligible due to the elasticity of the heat conducting member. If the thickness, length, etc. are managed, a substantially desired thermal resistance can be realized.
[0038]
FIG. 10 shows the heat balance of the second embodiment in which a heat conducting member having a thermal conductance of 0.3 W / mK is applied. From this figure, it can be seen that when the temperature of the ceramic plate is 400 ° C., 300 ° C., and 200 ° C., the controllable heat input amounts are increased to 921 W, 477 W, and 202 W, respectively.
[0039]
Therefore, according to the present embodiment, since the conductive member is sandwiched between the ceramic plate and the cooling jacket by heat, if the heat input is 202 W or less with a simple structure as in the first embodiment, the temperature is 200 ° C. to 500 ° C. A uniform temperature distribution can be realized over a wide temperature range at a high temperature such as ° C.
[0040]
In addition, the shape of the heat conducting member of the present embodiment was a ring shape and was arranged coaxially with respect to the central axis of the cooling jacket. This is because the heat transfer distribution was taken into consideration so as to be an axial object. However, it is not necessarily limited to this structure. For example, a plurality of small ring-shaped heat conducting members may be arranged. What is important is that the heat conducting member has elasticity in the thickness direction and the thermal resistance is controlled. If the heat conducting member is arranged near the outer periphery as in the embodiment, the entrapment of reaction products and deposition gas is reduced, so that the effect of reducing the number of cleaning of the apparatus and extending the life can be expected.
[0041]
FIG. 11 shows the measurement result of the temperature distribution in the wafer surface when the wafer is held using the wafer processing apparatus of this embodiment. The wafer temperature was measured using a thermocouple embedded wafer manufactured by Sensory Japan. From this figure, it can be seen that a substantially uniform temperature distribution can be realized, with the wafer average temperature being within ± 7 ° C. from 283 ° C. to 414 ° C.
[0042]
FIG. 12 shows the surface of the cooling jacket of the third embodiment of the present invention. In this embodiment, in order to introduce the two heat conducting members of the second embodiment, the groove 26 is added inside the groove 25. This example is an effective means for further improving the heat transfer capability of the heat conducting member when the heat input to the wafer is even greater than in the second embodiment. FIG. 13 shows the heat balance when the thickness and shape of the heat conducting member are all considered, two heat conducting members are provided, and the thermal conductance is 1 W / K. From this figure, it can be seen that when the temperature of the ceramic plate is 400 ° C., 300 ° C., and 200 ° C., the controllable heat input amounts are increased to 1168 W, 652 W, and 307 W, respectively.
[0043]
As described above, the surface of the heat conducting member is not particularly treated in the embodiment, but if the surface is plated with a soft metal such as Ni plating or gold plating, the reproducibility of the contact state between the ceramic plate and the cooling jacket is further increased. .
[0044]
As described above, in the embodiment of the present invention, the case where the temperature of the bell jar, which is the opposite surface of the wafer stage, is adjusted from 70 ° C. to 120 ° C. is described, but it is not always necessary to adjust the temperature. When temperature control is not performed, the structure of the processing apparatus is simplified and the effect of reducing costs can be expected. However, in that case, the temperature of the bell jar also rises as the number of processed sheets increases, the effect of exhaust heat due to radiation to the bell jar is reduced, and the controllable wafer bias power is reduced. In addition, under conditions where reactive organisms adhere to the inner wall of the bell jar, there are also problems such as changes in etching characteristics due to changes in the deposit state, and it is up to the operator to decide whether or not to adjust the temperature. Is.
[0045]
As described above, in the embodiments of the present invention, the electrostatic chuck for fixing the wafer is a so-called monopole system in which the internal electrode is a single electrode. However, the electrostatic chuck is not necessarily limited to this. That is, a so-called bipolar system having two independent electrodes as internal electrodes for the electrostatic chuck may be used. Although this method requires two electrodes inside, the structure is complicated, and there are drawbacks such as the need for two power supplies. However, even without plasma, the wafer can be adsorbed and plasma processing can be performed. Since the cooling gas can be introduced to the back surface of the wafer before the start, there is an advantage of excellent temperature controllability.
[0046]
As described above, in the processing apparatus according to the embodiment of the present invention, the plasma source is inductively coupled plasma, but it is not necessarily limited to this method. For example, a parallel plate type plasma source may be used, a UHF band electromagnetic wave radiation discharge system, a microwave system, or a plasma system using a VHF band from several tens of MHz to about 300 MHz may be used. Other than this, for example, a magnetron type plasma processing apparatus using a magnetic field may be used. Of these methods, which plasma method to use is selected according to the characteristics of the material to be actually processed, and may be appropriately selected. As described above, according to the above-described embodiment, the wafer can be maintained at a uniform temperature distribution over a wide range from 200 ° C. to 500 ° C. with a very simple configuration, and the temperature fluctuation can be maintained even during processing. Therefore, a nonvolatile material that cannot be etched by a normal process can be etched.
[0047]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a wafer processing apparatus capable of maintaining a uniform temperature distribution of a wafer in a wide temperature range.
[Brief description of the drawings]
FIG. 1 shows a wafer processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a view showing a wafer stage according to a first embodiment of the present invention.
FIG. 3 is a diagram showing a heat balance model of an embodiment of the present invention.
FIG. 4 is a view showing a first heat balance of the present invention.
FIG. 5 is a diagram showing heat balance when a black paint is applied to the surface of the cooling jacket of the first embodiment of the present invention.
FIG. 6 is a diagram showing a second embodiment of the present invention.
FIG. 7 is a perspective view of a cooling jacket according to a second embodiment of the present invention.
FIG. 8 is a view showing a heat conducting member according to a second embodiment of the present invention.
FIG. 9 is a cross-sectional view of a heat conducting member according to a second embodiment of the present invention.
FIG. 10 is a diagram showing the heat balance of the second embodiment of the present invention.
FIG. 11 is a view showing a wafer temperature distribution according to the second embodiment of the present invention.
FIG. 12 is a perspective view of a cooling jacket according to a third embodiment of the present invention.
FIG. 13 is a diagram showing the heat balance of the third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Wafer stage, 3 ... Flow controller, 4 ... Gate valve, 5 ... High frequency power supply, 6 ... Plasma, 7 ... Coil, 8 ... High frequency power supply, 9 ... Vacuum chamber, 10 ... Berja, 11 ... Etching Gas, 12 ... Valve, 13 ... Turbo molecular pump, 14 ... Cooling jacket, 15 ... Ceramic plate, 16 ... Heater, 17 ... Internal electrode, 19 ... Feed line, 20 ... Shaft, 21 ... Coil, 22 ... DC power supply, 23 ... Spacer, 24 ... Heat conducting member, 25 ... Groove, 26 ... Groove, 27 ... Fan, 28 ... Heater output, 29 ... Through hole, 30 ... Flexible water piping, 31 ... Radiation heat transfer to cooling jacket, 32 ... pusher pins, 33 ... radiation heat transfer to the bell jar, 34 ... plasma heat input, 35 ... bellows, 36 ... zirconia ceramic bolts, 38 ... radiation insulation, 39 ... Throughbore, 41 ... socket 42 ... electric plug, 46 ... groove, 52 ... seal, 53 ... depression, 54 ... through hole, 55 ... sheath thermocouple, 56 ... sheath, 57 ... coil spring, 58 ... presser

Claims (4)

A wafer processing apparatus for processing a semiconductor wafer held on a wafer stage disposed in a vacuum chamber whose inside is evacuated by using plasma formed in the vacuum chamber,
The wafer stage has a metal cooling jacket in which a flow path through which a refrigerant flows is disposed, and is placed on the cooling jacket with a predetermined distance above the cooling jacket and disposed at a predetermined distance. A ceramic plate-like member in which an electrode and a heater are disposed, and a space is formed between the plate-like member and the cooling jacket placed on the upper surface of the cooling jacket with the distance therebetween And a hole for supplying a heat transfer gas between the spacer and a back surface of the wafer in a state where the wafer is held, and the space communicates with the inside of the vacuum chamber. A wafer processing apparatus in which heat is transferred between the cooling jacket and the plate-like member by heat transfer of radiation through the space. 2. The wafer processing apparatus according to claim 1, wherein unevenness is formed on a surface of the cooling jacket constituting the space. A wafer stage which is disposed in a vacuum chamber and holds a wafer to be processed thereon, a metal cooling jacket having a flow path through which a coolant flows, and a cooling jacket above the cooling jacket A ceramic plate-like member in which an electrode and a heater, which are placed with a predetermined distance from the upper surface and are supplied with high-frequency power, and a heater are disposed between the plate-like member and the cooling jacket. Means for forming a space at a distance, and a hole for supplying heat transfer gas between the wafer rear surface and the wafer disposed on the surface on which the wafer is held, A wafer stage in which a space communicates with the inside of the vacuum chamber, and heat is transferred between the cooling jacket and the plate-like member by heat transfer of radiation through the space. 4. The wafer stage according to claim 3, wherein irregularities are formed on a surface of the cooling jacket constituting the space .

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