JP3742349B2 - Plasma processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus applied to microfabrication such as a semiconductor manufacturing process, and more particularly to a plasma processing apparatus provided with a holding stage for mounting a semiconductor wafer.
[0002]
[Prior art]
As semiconductor elements have been highly integrated in recent years, circuit patterns have been increasingly miniaturized, and the required processing dimension accuracy has become increasingly severe. In addition, at this time, it is required to improve the throughput and increase the area of the workpiece, and the temperature controllability of the semiconductor wafer during processing is extremely important.
[0003]
For example, in an etching process that requires a high aspect ratio (thin and deep groove), anisotropic etching is required, and in order to realize this, a process of performing etching while protecting the sidewall with an organic polymer is used. In this case, the production of the organic polymer serving as the protective film varies depending on the temperature. At this time, if the temperature in the semiconductor wafer surface during the etching process is unevenly distributed, the degree of generation of the sidewall protective film may vary in the wafer surface, resulting in a problem that the etching shape also becomes uneven. is there.
[0004]
In addition, the reaction product may reattach to the etching surface and reduce the etching rate, but this reaction product tends to be distributed more in the center of the semiconductor wafer than in the vicinity of the periphery of the semiconductor wafer. The etching rate is low as compared with the vicinity, and accordingly, the etching shape in the semiconductor wafer surface varies in the wafer surface.
[0005]
Here, as a method for improving this, a method in which the temperature near the wafer center is made higher than that near the outer periphery to suppress the reattachment of reactive organisms to the etching surface is effective. It is necessary to control the temperature of the semiconductor wafer inside so as to cancel out the distribution of the reaction product by making it uniform in the plane or arbitrarily in the plane of the semiconductor wafer. .
[0006]
By the way, the temperature control of the semiconductor wafer being processed is generally realized by controlling the surface temperature of the electrostatic adsorption electrode (holding stage) on which the wafer is placed. As a method for dealing with this temperature control, for example, JP 2000-216140 A (Prior Art 1) can be cited.
[0007]
In this prior art 1, a plurality of independent refrigerant flow paths capable of controlling the flow rate of the refrigerant are provided in the metal electrostatic adsorption electrode block constituting the holding stage, and a dielectric film is formed on the surface of the electrode block. The structure is provided.
[0008]
In Japanese Patent Laid-Open No. 9-17770 (prior art 2), in order to control the in-plane temperature distribution of the semiconductor wafer, two lines of coolant channels are provided concentrically inside the electrostatic adsorption electrode, A structure in which a relatively low temperature refrigerant is circulated in the refrigerant channel and a relatively high temperature refrigerant is circulated in the inner refrigerant channel is disclosed in Japanese Patent Application Laid-Open No. 8-45909 (Prior Art 3). There is disclosed a sample stage (holding stage) for dividing a manufactured electrode block and providing a refrigerant flow path or a heater for each, and performing temperature control.
[0009]
[Problems to be solved by the invention]
The prior art described above has a problem in that it does not consider the heat flow in the electrostatic adsorption electrode and positively realizes a clear temperature distribution.
[0010]
For example, in the prior arts 1 and 2, the temperature or flow rate of the coolant is controlled in order to realize a temperature distribution that makes the temperature near the center of the semiconductor wafer being processed higher than the temperature near the periphery of the wafer. Due to the thermal conductivity of the block, a clear temperature distribution cannot be obtained in the plane, and at this time, since the flow paths of the refrigerant are adjacent to each other, the temperature becomes uniform in the electrode block. Furthermore, a clear temperature distribution cannot be obtained.
[0011]
On the other hand, in the electrostatic chucking electrode disclosed in the prior art 3, temperature control can be independently performed in the divided electrode block, and in-plane temperature distribution control can be obtained, but there is a gap between the blocks. Therefore, it is difficult to form a thin dielectric film with high reliability.
[0012]
Further, in the prior art 1, since the electrode block is fixed with screws only at the circumferential portion, the electrode block is deformed into a convex shape by the pressure of the refrigerant, and in some cases, the semiconductor wafer cannot be uniformly adsorbed. In some cases, an undesirable temperature distribution is generated in the semiconductor wafer surface.
[0013]
An object of the present invention is to provide a wafer processing apparatus capable of positively controlling the temperature distribution of a semiconductor wafer during an etching process in a clear state.
[0014]
[Means for Solving the Problems]
  The object of the present invention is to provide a plasma processing apparatus having a holding stage that controls the temperature of an electrode block and controls the temperature of a semiconductor wafer.A first flow path and a second flow path independently provided inside and outside the electrode block, a heat transfer suppression slit disposed between the first flow path and the second flow path, First and second heating medium supply means for independently supplying a heating medium whose temperature and flow rate are controlled to the first and second flow paths independently;This is achieved as described above.
  At this time, the heat transfer suppressing slits may be formed substantially concentrically.
[0015]
Also, at this time, the temperature control means independent on the inner side and the outer side are provided in the electrode block independently on the inner side and the outer side of the electrode block, and the first and second flow paths. The above object can be achieved even if the first and second heat medium supply means are configured to supply the first and second flow paths independently with at least one of the temperature and flow rate controlled heat medium. The temperature control means independent on the inner side and the outer side are provided in the electrode block independently on the inner side and the outer side of the electrode block, and the first and second flow paths. A heat medium supply means for commonly supplying a heat medium whose temperature and / or flow rate is controlled to the flow path, and a temperature adjusting means provided in a pipe line connecting the first and second flow paths. Even if it does, the said objective is achieved.
[0016]
Further, the temperature adjusting means may be composed of a heater, which may be provided on the back surface of the electrode block, or may be built in the electrode block.
[0017]
Next, the electrode block may be provided with a dielectric film on a surface thereof, and a heater may be built in the dielectric film, and the heater is also used as an electrode of the electrostatic adsorption electrode. You may make it do.
[0018]
Further, the electrode block is composed of one member in which the flow path of the heat medium is formed and the other member for ensuring the rigidity of the electrode block, and these members may be fastened together. The means for fastening the one member to the other member may be any of screwing, brazing, diffusion bonding, and electron beam welding, and the other member for ensuring the rigidity is The electrode block may be made of a material having a lower thermal conductivity.
[0019]
Or the said 1st and 2nd flow path may be formed by piping of the circular cross section or polygonal cross section attached to the said electrode block, and also the said piping may be built in the said electrode block.
[0020]
At this time, the electrode block may include at least three temperature sensors, and the temperature may be controlled based on information of these temperature sensors. A dielectric film is provided on the surface of the electrode block, and the dielectric You may comprise as an electrostatic adsorption electrode into which the gas for heat conduction is introduce | transduced between a body film and the said semiconductor wafer.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plasma processing apparatus according to the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 is an embodiment of a plasma processing apparatus P according to the present invention, and FIG. 2 is a perspective view of a partial cross section of an electrostatic adsorption electrode S used as a holding stage S of a semiconductor wafer W in this plasma processing apparatus. It is. This holding stage is generally called an electrostatic chucking electrode, and therefore will be referred to as an electrostatic chucking electrode S hereinafter.
[0022]
And in the case of the electrostatic chucking electrode S according to this embodiment,FIG.WhenFIG.As described above, a flow path of a fluid (heating medium) acting as a refrigerant or a heating medium is provided,FIG.As shown in FIG. 2, the apparatus is installed and used in a plasma processing apparatus according to an embodiment of the present invention.
[0023]
As shown in FIG. 2, the electrostatic adsorption electrode S is made of an electrode block 1 made of aluminum.( Thickness 25mm )And stainless steel guide member 2( 10mm thickness ), Base member 3( 10mm thickness )The dielectric film 4 and the electrode cover 5 made of ceramics, for example, when a 12-inch (300 mm diameter) semiconductor wafer is targeted, the diameter is 320 mm and the overall thickness isAbout 45It is made to be mm.
[0024]
Here, first, on the lower surface of the electrode block 1, as shown in FIG. 3, flow path slits 11, 12 arranged in a spiral shape are formed separately on the inner diameter side and the outer shape side. Between them, a substantially concentric heat transfer suppressing slit 13 (radius = 90 mm, width = 5 mm, height (depth) = 18 mm) is formed.
[0025]
And the guide member 2 is piled up on the lower surface of this electrode block 1, and it fixes with the volt | bolt 6, and the opening part of each slit 11, 12, 13 is block | closed. At this time, the gas introduction hole 7 is provided through the electrode block 1 and the guide member 2 including the base member 3.
[0026]
Next, the dielectric film 4 is made of, for example, high-purity alumina ceramic and has a thickness of 0.1 mm. However, the material and thickness of the dielectric film 4 are not limited to this example. For example, in the case of a synthetic resin, a thickness of 0.1 mm to several mm can be selected accordingly.
[0027]
As shown in FIG. 2, the dielectric film 4 is provided with linear slits 41 extending radially and communicating with the gas introduction holes 7, and a plurality of concentric slits 42 communicating with the slits. Thus, when the semiconductor wafer W is placed on the electrostatic adsorption electrode S, the heat transfer He gas is introduced into the gap between the dielectric film 4 and the semiconductor wafer W from the gas introduction hole 7. It is like that.
[0028]
The flow path slits 11 and 12 of the electrode block 1 are respectively provided with refrigerant (or heat medium) introduction parts 11A and 12A and discharge parts 11B and 12B. , 12 are configured to be able to function as mutually independent heat medium flow passages for allowing the temperature control refrigerant to flow therethrough.
[0029]
The introduction portions 11A and 12A and the discharge portions 11B and 12B of the flow path slits 11 and 12 are connected to independent refrigerant supply units 51 and 52, respectively, and at least the flow rate and temperature of the refrigerant to be circulated respectively. One can be adjusted individually.
[0030]
Here, the arrangement shape of the flow path slits 11 and 12 is not limited to the spiral shape shown here. For exampleFIG.Is a case where the flow path slits 11 and 12 are formed in a plurality of concentric circles, respectively, and in this case, the refrigerant flows in a semicircular direction in opposite directions.
[0031]
Next, the operation of the plasma processing apparatus according to this embodiment will be described. First, the electrostatic adsorption electrode S is mounted in the processing chamber shown in FIG. 1, the semiconductor wafer W is placed, and chlorine-based or fluorine-based gas is introduced. , The atmosphere generated in the processing chamber by the microwave generated by the magnetronToThe plasma is excited to excite the plasma, and the distribution and density of the plasma are controlled by the magnetic field generated by the solenoid coil.
[0032]
Along with this, a DC voltage and a high frequency are applied to the electrode block 1 (FIG. 2) of the electrostatic chucking electrode S, and etching is performed while controlling the temperature of the semiconductor wafer W.
The embodiment of the plasma processing apparatus according to the present invention is not limited to the system using the magnetron shown here, and other types of plasma processing apparatuses may be used.
[0033]
Next, the operation of the electrostatic chucking electrode S in this embodiment will be described first from the principle of temperature control.
First, the electrostatic adsorption electrode S is for adsorbing the semiconductor wafer W by Coulomb force or Johnson Lambeck force expressed by applying a high voltage to the dielectric film 4. There are two application methods, a monopolar type and a bipolar type.
[0034]
First, the monopolar type is a method of giving a uniform potential between the semiconductor wafer and the dielectric film, and the bipolar type is a method of giving two or more kinds of potential differences between the dielectric films. In this embodiment, Any method may be used.
[0035]
After the adsorption, the heat transfer He gas (usually about 1000 kPa) is introduced between the semiconductor wafer W and the dielectric film 4 from the gas introduction hole 7 as described above. Therefore, the temperature of the semiconductor wafer W includes the heat input from the plasma, the heat passage rate of the gap filled with He gas, the thermal resistance of the electrode block 1, and the refrigerant circulated in the electrode block 1 and the electrode block 1 It is defined by the heat transfer rate of
[0036]
Therefore, in order to control the temperature of the semiconductor wafer W, a mechanism for changing the pressure of the He gas with respect to the electrostatic adsorption electrode S, the temperature of the refrigerant, and the flow rate of the refrigerant (change of the heat passage rate with the electrode block) is provided. Alternatively, a second temperature adjustment mechanism such as a heater may be provided.
[0037]
For example, if the flow path slits 11 and 12 are 5 mm wide × 15 mm high, and the flow rate of the refrigerant at 20 ° C. is doubled from 2 L / min to 4 L / min, the refrigerant and the electrode block 1 It has been confirmed that the heat transfer rate during the period is about 200 W / m 2 K to about 400 W / m 2 K. Therefore, since the heat passage rate can be increased by increasing the flow rate of the refrigerant, the temperature rise of the electrode block 1 can be suppressed small even if the heat input from the plasma increases.
[0038]
By the way, in a general electrostatic attraction electrode, due to its structure, although the heat input from the plasma is uniform, a temperature distribution occurs in the semiconductor wafer surface as follows. First, since the pressure of the He gas introduced between the semiconductor wafer and the dielectric film is higher than the pressure in the chamber (processing chamber) during plasma generation, the He gas leaks from the outermost peripheral portion of the semiconductor wafer W. . The actual measurement is 2 to 5 ml / min.
[0039]
FIG. 5 is an example of the calculation result at this time, and the graph shown here shows the pressure on the back surface of the semiconductor wafer obtained from the leak amount of He gas.distributionAs shown in this figure, since the pressure of the He gas on the outermost periphery of the semiconductor wafer is higher than the pressure in the chamber during plasma generation, it rapidly decreases at the outer periphery of the semiconductor wafer.
[0040]
Next, FIG. 6 shows the surface temperature of the semiconductor wafer W when the heat input is uniform in the plane of the semiconductor wafer. This figure shows that the fluorine processing is performed using the plasma processing apparatus shown in FIG. Results when plasma is generated in an atmosphere introduced with gas (pressure 1 Pa), the flow rate of the refrigerant is 5 L / min, and the temperature is 35 ° C. The horizontal axis is the distance from the center of the semiconductor wafer, and the vertical axis is the semiconductor wafer. The surface temperature indicates the measured value, and the solid line indicates the analytical value.
[0041]
Accordingly, it can be seen from FIGS. 5 and 6 that the surface temperature of the outer peripheral portion of the semiconductor wafer is higher than that of the central portion due to the lower pressure of the He gas.
Next, assuming that the temperature difference in the semiconductor wafer surface is ΔT, this depends mainly on the high-frequency power applied to the electrostatic adsorption electrode. For example, when a power of 1300 W is applied, the temperature difference is about 10 ° C. Reached.
[0042]
Therefore, in order to give a gentle temperature distribution (for example, middle height or outer height) in the semiconductor wafer surface by the electrostatic adsorption electrode, temperature distribution control in consideration of the pressure distribution of He gas is required.
[0043]
By the way, the above is a case of a general electrostatic chucking electrode including the prior art. Next, the case of the electrostatic chucking electrode S according to the embodiment of the present invention shown in FIG. 1 will be described. In the embodiment, the electrode block 1 constituting the electrostatic adsorption electrode S is provided with a heat transfer suppressing slit 13 having a shape in which the inner peripheral portion and the outer peripheral portion are separated.
[0044]
Furthermore, in this electrostatic chucking electrode S, the slit 11 for flow path 11 and the slit 12 are independent on the inner peripheral side and the outer peripheral side of the electrode block 1 with the heat transfer suppressing slit 13 interposed therebetween. At least one of the flow rate and temperature of the refrigerant can be individually adjusted.
[0045]
Here, as described above, the heat transfer suppressing slit 13 remains closed by the guide member 2, so that the inside is filled with an atmosphere having a pressure substantially equal to the pressure in the processing chamber, Alternatively, it is in a vacuum state, so that it prevents heat from being transferred between the inner peripheral side and the outer peripheral side of the electrode block 1 and allows a large temperature difference to be generated on both sides.
[0046]
FIG. 7 is an example of the measurement result of the temperature distribution of the semiconductor wafer W obtained using the electrostatic adsorption electrode S provided with the heat transfer suppressing slit 13 in the electrode block 1 under the same conditions as in FIG. Here, it is assumed that the temperature of the central portion is relatively high with respect to the temperature of the outer peripheral portion. Here, the high frequency power of the electrostatic adsorption electrode S is 100 to 1300 W, and the refrigerant flow rate of the slit 11 is 1 to 4 L. / Min, the flow rate of the refrigerant in the slit 12 is in the range of 4 to 8 L / min.
[0047]
As shown in FIG. 7, in the electrostatic attraction electrode S having the heat transfer suppressing slit 13 as an embodiment of the present invention, the temperature of the central portion is kept low while the temperature of the outermost peripheral portion of the surface of the semiconductor wafer W is kept low. It can be seen that can be sufficiently high.
[0048]
Next, FIG. 8 shows the analysis result of the surface temperature of the dielectric film 4 at this time. As shown in FIG. 8, since the heat transfer suppressing slit 13 is also provided in this case, the dielectric film It can be seen that the temperature distribution on the surface of No. 4 is prominent and a so-called sharp temperature distribution is obtained. At this time, the temperature distribution changes greatly with the heat transfer suppression slit 13 as a boundary. I understand that.
[0049]
Here, in such an electrostatic adsorption electrode, as described above, due to the structure, the pressure of the He gas decreases at the outermost peripheral portion of the semiconductor wafer, and the temperature increases at the outermost peripheral portion of the semiconductor wafer. Therefore, in this embodiment, in order to keep the temperature of the outermost peripheral portion of the semiconductor wafer W low and increase the temperature of the central portion, it is necessary to provide the heat transfer suppressing slit 13 at an appropriate position. There is.
[0050]
In this embodiment, for example, the position of the heat transfer suppression slit 13 when the above-described semiconductor wafer W having a diameter of 300 mm is the target can be obtained if the distance from the center is in the range of 80 to 120 mm. This is in the range of 60 to 80 mm when the semiconductor wafer W has a diameter of 200 mm.
[0051]
Therefore, it can be seen from this result that in the electrostatic adsorption electrode S according to the embodiment of the present invention, it is desirable to provide the heat transfer suppressing slit 13 in the range of 50 to 80% of the radius of the electrode block 1.
Here, normally, the temperature distribution desired for the semiconductor wafer in the plasma processing is a moderate middle-high or outer-high distribution in the circumferential direction. Therefore, the heat transfer suppressing slit 13 of the electrostatic adsorption electrode S is concentric. It is desirable to form.
[0052]
On the other hand, the cross-sectional shape of the heat transfer suppressing slit 13 is preferably a rectangle or a trapezoid from the viewpoint of processing. In this case, however, the height dimension is more important, that is, the height of the electrode block 1 is higher. The effect of suppressing heat conduction increases as the thickness becomes the same size. However, if the height of the heat transfer suppressing slit 13 is increased in this manner, the rigidity of the electrode block 1 is lowered. In this case, a rib is provided in the middle of the slit so that the rigidity of the electrode block 1 is not lowered. Anyway.
[0053]
Therefore, according to the embodiment of the present invention, the temperature distribution of the semiconductor wafer W during the plasma etching can be clearly controlled. As a result, the temperature can be made uniform within the surface of the semiconductor wafer, and the medium-high type and the outer high-type can be clearly defined. The temperature distribution can be controlled in any state and can be arbitrarily controlled. As a result, the distribution of reaction products can be offset, and plasma treatment that suppresses the reattachment of reactive organisms to the etched surface can be easily handled. This can greatly contribute to an improvement in the yield of semiconductor wafer processing.
[0054]
Next, another embodiment of the present invention will be described. First, FIG. 9 shows a second embodiment of the present invention.EmbodimentThus, a slit 13 for suppressing heat transfer is provided in the electrode block 1, and a slit 14 serving as an inner peripheral side refrigerant passage and a slit 12 serving as an outer peripheral side refrigerant passage are connected in series by a pipe line 14. In addition, an electrothermal heater 15 is provided in the conduit 14 to form an electrostatic adsorption electrode S1.
[0055]
And in this electrostatic adsorption electrode S1, the refrigerant | coolant is supplied to the slit 11 and the slit 12 used as the refrigerant | coolant flow path in the electrode block 1 from the one refrigerant | coolant supply unit 53, At this time, the heater 15 The temperature is controlled by a power control device (not shown), and the refrigerant passing through the pipe line 14 is heated to a predetermined temperature.
[0056]
Therefore, according to the electrostatic adsorption electrode S1, the temperature distribution of the semiconductor wafer W can be easily changed to the middle-high temperature distribution or the outer high-temperature distribution by adjusting the heating temperature of the refrigerant by the heater 15.
[0057]
That is, for example, when the temperature of the semiconductor wafer W is set to the medium-high temperature distribution, it is only necessary to circulate the refrigerant in the direction indicated by the solid-line arrow and control the heating temperature of the refrigerant by the heater 15. When it is desired to circulate, the refrigerant may be circulated in the direction indicated by the dotted arrow.
[0058]
Therefore, the electrostatic adsorption electrode S1 can also clearly control the temperature distribution of the semiconductor wafer W during plasma etching, as in the electrostatic adsorption electrode S described with reference to FIGS. It is possible to control the temperature distribution in a uniform state in the inside, a clear temperature distribution such as a medium-high type or an external high-type, and arbitrarily control it. As a result, the distribution of reaction products is offset and etching of reactive organisms is performed. Plasma processing that suppresses redeposition to the surface can be easily handled, and can greatly contribute to the improvement of the yield of semiconductor wafer processing.
[0059]
Moreover, according to the electrostatic adsorption electrode S1, it is only necessary to install one refrigerant supply unit 53, so that the configuration of the apparatus can be simplified.
Further, in the case of the electrostatic adsorption electrode S1 of this embodiment, if the heater 15 is installed in the pipe line 14, the space can be used effectively, and it is extremely effective from the viewpoint of thermal efficiency.
[0060]
In the embodiment of FIG. 9, the case where the heater 15 is an electrothermal type has been described. However, a Peltier element may be used as the heater 15, and in this case, the refrigerant in the pipe line 14 is heated. Not to mention it can be cooled.
[0061]
Next, FIG. 10 shows a third embodiment of the present invention in which the heater 15 is embedded in the electrode block 1 to form the electrostatic adsorption electrode S2. At this time, in this embodiment, the heater 15 is cast. It is cast into the electrode block 1 using a technique. In this case, as the heater 15, a so-called sheathed heater in which a nichrome wire or a tungsten wire is covered with an insulating material such as alumina and placed in a stainless steel tube or a steel tube is used.
[0062]
Further, as a similar structure, a heater having a film structure in which a dielectric film 4 is multilayered and a tungsten film is sandwiched therebetween, for example, a film having an alumina / tungsten / alumina structure, may be formed. A structure in which a tungsten heater is also used as the electrode of the electrostatic adsorption electrode may be used.
[0063]
According to the above embodiment, the temperature of the semiconductor wafer W can be arbitrarily controlled and the thermal efficiency can be dramatically improved by providing the heat transfer suppressing slit 13 in the electrode block 1, but this heat transfer suppressing It is conceivable that the rigidity of the electrode block 1 is reduced by providing the slit 13 for use.
[0064]
Therefore, next, an embodiment of the present invention in which a decrease in rigidity due to the provision of the slit is suppressed will be described with respect to the case of the electrostatic chucking electrode S of FIG. 1. In this case, FIG. As shown in FIG. 1, the electrostatic chucking electrode S includes an electrode block 1 and a guide member 2. Although not shown in FIG. 1, the guide member 2 is fastened to the electrode block 1 with a bolt 6 by fitting an O-ring 16 on the outermost periphery.
[0065]
Here, the pressure P of the refrigerant passing through each of the slits 11 and 12 is usually about 500 KPa. However, since this is applied to each of the slits 11 and 12, the electrode block 1 is exaggerated by a broken line in FIG. Deform as depicted.
[0066]
Therefore, in order to deal with such a deformation and prevent it, as shown in FIG. 12, the radius of the electrode block 1 is half the position, and it can be fastened with another bolt 60 from the back surface of the guide member 2. As a result, deformation can be suppressed as exaggeratedly drawn with a broken line.
[0067]
According to the actual measurement, when only the outermost periphery of the electrode block 1 having a diameter of 320 mm and a thickness of 25 mm was fastened, a deformation of about 0.5 mm was observed at the center, but as shown in FIG. When this was provided, almost no deformation was observed, and good results were obtained.
[0068]
By the way, in the case of the said embodiment, if the guide member 2 is made with a material whose heat conductivity is lower than that of the electrode block 1, the electrostatic adsorption electrode S is more excellent in thermal efficiency. Here, as described above, in the above embodiment, as described above, the material of the electrode block 1 is aluminum and the material of the guide member 2 is stainless steel, which meets the above conditions.
[0069]
Here, the fastening method of the electrode block 1 and the guide member 2 is not limited to the above-described screw fastening with bolts. For example, a fastening method such as brazing, diffusion bonding, or electron beam welding may be used.
[0070]
Next, as another embodiment of the present invention, an electrostatic adsorption electrode particularly excellent in temperature response will be described. First, FIG. 13 shows a refrigerant flow path in the electrode block 1 in the fourth embodiment of the present invention. Instead of forming the slit, the electrostatic chucking electrode S3 when the pipes 17 and 18 are brazed to the lower surface is shown. Next, FIG. 14 shows a fifth embodiment of the present invention.17,18The electrostatic chucking electrode S4 according to the present invention is shown in the case where the heater 20 and 21 are individually brazed after being partially embedded in the lower surface of the electrode block 1 and brazed.
[0071]
Here, in FIGS. 13 and 14, the pipe 17 forms an inner peripheral side refrigerant flow path, and the pipe 18 forms an outer peripheral side refrigerant flow path. Here, each of the pipes 17 and 18 is a square pipe, but may have an arbitrary polygonal cross-sectional shape, or may be a normal circular pipe.
[0072]
Therefore, first, the electrostatic chucking electrode S3 of FIG. 13 is substantially the same as the electrostatic chucking electrode S shown in FIG. 1, but since the electrode block 1 can be made thin, the temperature response is excellent.
[0073]
Further, the electrostatic adsorption electrode S4 of FIG. 14 is also excellent in temperature response, but in this case, the heaters 20 and 21 are provided on the inner peripheral side and the outer peripheral side of the heat transfer suppressing slit 13, respectively. By controlling the temperature by these power control devices 22 and 23, it is possible to obtain a temperature distribution with finer changes.
[0074]
Here, as an example, the power supplied to each of the heaters 20 and 21 is 300 W, the flow rate of the refrigerant is circulated at 4 L / min, and the temperature characteristics are measured. As a result, the medium-high type having a temperature difference of 15 ° C. And the outer high temperature distribution was easily realized.
[0075]
According to the electrostatic adsorption electrodes S3 and S4 in FIGS. 13 and 14, the pressure of the refrigerant only acts in the pipes 17 and 18, and the electrode block 1 is not directly pressurized. There is no risk of deformation in 1. At this time, the pipes 17 and 18 and the heaters 20 and 21 may be cast into the electrode block 1.
[0076]
By the way, although the above has shown about embodiment in case the slit 13 for heat transfer suppression currently formed in the electrode block 1 is 1 item | strip | row, it is made to provide the slit 13 for heat transfer suppression | exclusion as needed. In addition, according to this, it is possible to easily cope with the realization of a temperature distribution having a finer change pattern, and the semiconductor wafer can be controlled to an arbitrary temperature distribution.
[0077]
Here, in the above-described embodiment, it is necessary to provide a plurality of temperature sensors in the electrode block 1 in order to control the electrostatic adsorption electrode S and the like to a predetermined temperature distribution. In this case, as described above, the temperature of the outermost peripheral portion of the semiconductor wafer usually tends to be relatively high in the surface of the semiconductor wafer. By providing at least three locations individually, it is possible to control while monitoring the temperature distribution such as the middle-high type and the outer-high type.
[0078]
【The invention's effect】
According to the present invention, the electrode block is provided with a slit for suppressing heat conduction and an independent temperature control mechanism at the inner and outer circumferences sandwiching the slit, so that the temperature is controlled independently in the surface direction of the electrode block. As a result, it is possible to easily cope with the temperature distribution pattern change of the semiconductor wafer.
[0079]
As a result, processing of a semiconductor wafer rich in changes due to various different temperature distribution patterns can be obtained, which can greatly contribute to improving the performance of the semiconductor wafer.
[0080]
Further, according to the present invention, the heat medium flow path is composed of divided members, and each divided member is fastened by screws, brazing, diffusion bonding, or electron beam welding. It is possible to easily cope with deformation of the electrode block due to pressure.
[0081]
At this time, according to the present invention, the refrigerant flow path can also be formed by a pipe having a circular or polygonal cross section, so that general-purpose parts can be used and the heat capacity of the electrode block is reduced. An electrostatic adsorption electrode and a plasma processing apparatus excellent in response can be provided.
[0082]
Therefore, according to the plasma processing apparatus of the present invention, it is possible to arbitrarily set the temperature control of the semiconductor wafer and easily cope with uniform etching, so that the yield of the semiconductor element can be greatly improved and the cost can be sufficiently reduced. Obtainable.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of a plasma processing apparatus according to the present invention.
FIG. 2 is a perspective view showing an embodiment of an electrostatic adsorption electrode in the plasma processing apparatus of the present invention.
FIG. 3 is an explanatory view showing the arrangement of slits in another embodiment of the electrostatic chucking electrode according to the present invention.
FIG. 4 is an explanatory view showing the arrangement of slits in another embodiment of the electrostatic chucking electrode according to the present invention.
FIG. 5 is a characteristic diagram illustrating an example of a pressure distribution of He gas between an electrostatic chucking electrode and a semiconductor wafer.
FIG. 6 is a characteristic diagram showing an example of the surface temperature of a semiconductor wafer by an electrostatic chucking electrode.
FIG. 7 is a characteristic diagram showing an example of the surface temperature of a semiconductor wafer according to an embodiment of the electrostatic chucking electrode according to the present invention as compared with the prior art.
FIG. 8 is a characteristic diagram showing an example of the surface temperature of a dielectric film according to an embodiment of the electrostatic chucking electrode according to the present invention as compared with the prior art.
FIG. 9 is a cross-sectional view showing a second embodiment of the electrostatic chucking electrode according to the present invention.
FIG. 10 is a cross-sectional view showing a third embodiment of the electrostatic chucking electrode according to the present invention.
FIG. 11 is an explanatory view showing an example of deformation appearing in the electrode block of the electrostatic chucking electrode according to the present invention.
FIG. 12 is an explanatory view showing another example of the deformation appearing in the electrode block of the electrostatic chucking electrode according to the present invention.
FIG. 13 is a cross-sectional view showing a fourth embodiment of the electrostatic chucking electrode according to the present invention.
FIG. 14 is a cross-sectional view showing a fifth embodiment of the electrostatic chucking electrode according to the present invention.
[Explanation of symbols]
S S1-S4 Electrostatic adsorption electrode
W Semiconductor wafer
1 Electrode block (holding stage)
2 Guide members
3 Base member
4 Dielectric film
5 Electrode cover
6 bolts
7 Gas introduction hole (for introducing He gas for heat transfer)
11, 12 Channel slit
11A, 12A refrigerant (or heat medium) introduction part
11B, 12B Refrigerant (or heat medium) discharge part
13 Heat transfer suppression slit
14 pipeline
15 Heater
16 O-ring
17, 18 Piping
20, 21 Heater
22, 23 Power control device
51, 52, 53 Refrigerant supply unit

Claims (2)

In the plasma processing apparatus provided with a holding stage of a system for controlling the temperature of the electrode block and controlling the temperature of the semiconductor wafer,
A first flow path and a second flow path provided independently inside and outside the electrode block in the electrode block;
A slit for suppressing heat transfer installed between the first and second flow paths;
The first and second flow paths are provided with first and second heat medium supply means for independently supplying a heat medium whose temperature and / or flow rate is controlled independently. Plasma processing equipment. In the invention of claim 1,
The plasma processing apparatus, wherein the first and second flow paths are formed by pipes having a circular cross section or a polygon cross section attached to the electrode block .

Images