JPH1064985A - Wafer stage, wafer temperature adjusting method and dry etching apparatus - Google Patents

Abstract

(57) [Problem] To provide a wafer stage capable of changing a wafer temperature in a short time without affecting the throughput. SOLUTION: An electrostatic chuck 3 provided with a dielectric 6 made of an insulating material and an electrode 7 made of a conductor, and an electrostatic chuck 3
And a metal jacket 2 joined to the wafer stage 1. The electrode 7 is formed by a brazing layer for fixing the dielectric 6 to the metal jacket 2. The metal jacket 2 is formed by embedding a heater 4 and a refrigerant pipe 5 connected to a cooling means therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer stage which is used in an apparatus for manufacturing a semiconductor device such as an etching apparatus and mounts a wafer and adjusts the temperature of the wafer. And a dry etching apparatus provided with the wafer stage.

[0002]

2. Description of the Related Art In recent years, the demand for microfabrication in VLSIs has become increasingly severe. A compatible treatment method is indispensable. By the way, when a material other than an oxide film is plasma-etched, anisotropic shape is ensured by the existence of a so-called sidewall protective film, as is well known. That is, this side wall protective film is
Various deposits, including organic polymers, are formed by the reaction products generated during plasma etching being re-dissociated in the plasma, and are formed by depositing on the sidewalls of the pattern. And protects the side walls from being etched.

However, since the sidewall protective film is formed by deposits from reaction products, if the pattern formed by etching is, for example, a ridge, the sidewall protective film is relatively small if its width is small. Becomes too thick, and the overall pattern width is made larger than a desired width. Similarly, when the pattern formed by etching is a concave groove, if the width is small, the side wall protective film becomes relatively too thick, and the overall pattern width is made smaller than desired. Therefore, as described above, as the miniaturization of various patterns progresses and the pattern width becomes narrow (narrow),
If the anisotropy of the etching is to be ensured by using the sidewall protective film, the dimensional accuracy of the obtained pattern is reduced.

In order to solve such inconvenience, recently,
Attempts have been made to secure dimensional accuracy by performing etching while performing high-speed exhaust, and attention has been paid. This high-speed evacuation process shortens the residence time of the etching gas during the etching process by installing a pump having a higher evacuation speed than the conventional etching processing apparatus and improving the conductance of the etching gas. This suppresses the reaction products from being redissolved in the plasma during the treatment. According to such a high-speed exhaust process, the amount of deposits due to the re-dissociation of reaction products can be significantly reduced.
The absolute value of the dimensional conversion difference and its variation can be suppressed very effectively.

However, in the above-described high-speed exhaust process, since the reaction products are quickly exhausted, the supply source of the sidewall protective film is reduced, and the sidewall protective film is not formed to a sufficient thickness, so that the anisotropic shape is not obtained. This causes a new problem that the accuracy of the shape of the pattern obtained when over-etching is deteriorated because of insufficient securing of the pattern. In other words, when the bias applied to the substrate is lowered in order to secure the selectivity with the base during over-etching, the side wall protective film is thin and thus weak, so that side etching and notching cannot be avoided, and conversely, the shape is not ensured. Therefore, if the applied bias is increased, the selectivity with the base is reduced.

As a technique for solving the problem of the trade-off between the selectivity and the shape as described above and achieving both the selectivity and the anisotropic shape, the wafer temperature during etching is cooled to 0 ° C. or less. A so-called low-temperature etching technique has been proposed. This low-temperature etching technology was reported, for example, by the group of Mr. Taji et al. (Hitachi Central Research Institute) (1988 DRYPR
OCESS SYMPOSIUM "Low-Temperature Microwave Plasma
Etching ”), in which the radical reaction is suppressed by lowering the sample temperature, and anisotropy can be ensured even under a low substrate bias.

[0007]

However, this low-temperature etching technique has the following disadvantages. First
In addition, it is difficult to process materials having different vapor pressures of reaction products such as W polycide. This is because, when etching the W polycide, WCl _x generated when etching the WSi _x, because the vapor pressure of the reaction products such as WO _x Cl _y is low, the polysilicon to a convenient temperature to etch the sample When the results in low temperature, because it becomes impossible etching WSi _x.

Second, ΔT (difference between the set temperature of the sample stage and the wafer temperature) becomes large during etching. That is, for example, in the processing of a contact hole, although it is effective to lower the temperature to secure the selectivity with the underlying Si, the lowering of the temperature causes the taper of the contact hole shape due to excessive polymer deposition. difficult to set the low temperature conditions as the, moreover, the processing of the contact hole must be large anyway incident energy for cutting a Si-O bond, which is the resulting in an increase in the [Delta] T. Therefore, due to such inconvenience, even though low-temperature etching is performed, etching can actually be performed only at an incomplete temperature.

In order to solve such inconveniences, for example, the set temperature of a sample such as a wafer is set during etching of materials having different vapor pressures of reaction products, or between just etching and over etching. It can be changed. However, if such a change in the set temperature is performed during the etching process, the throughput is naturally reduced, which is disadvantageous in cost. Therefore, it is desired to provide a mechanism that can change the temperature of a wafer in a short time without affecting the throughput, that is, a mechanism that enables rapid temperature decrease and rapid temperature increase.

[0010] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a wafer stage capable of changing the temperature of a wafer in a short time without affecting the throughput, a method for adjusting the temperature of the wafer using the wafer stage, and a dry stage including the wafer stage. An etching apparatus is provided.

[0011]

Means for Solving the Problems Claim 1 of the present invention
In the described wafer stage, the electrostatic chuck includes a dielectric made of an insulating material and an electrode made of a conductor, and a metal jacket joined to the electrostatic chuck, and the electrode is made of a metal made of the dielectric material. The metal means jacket is formed by a brazing layer for fixing to a jacket made of metal, and the metal jacket is formed by embedding a refrigerant pipe connected to a heater and a cooling means therein.

According to this wafer stage, since the electrodes are formed by the brazing layer for fixing the dielectric to the metal jacket, the joining between the dielectric and the electrodes is ensured and the electrodes are made thin. Since the electrode can be formed, and the electrode is made of a brazing material, that is, a metal or an alloy having good heat conductivity, heat conduction from the metal jacket to the dielectric is quickened. Also, since the heater is embedded inside the metal jacket, for example, compared to incorporating the heater in an electrostatic chuck,
Since the metal jacket can be made larger than the electrostatic chuck, it is possible to increase the size of the heater, that is, to increase the capacity. Furthermore, since the refrigerant pipe is embedded in the metal jacket, the refrigerant pipe is reinforced by the metal jacket, and thus the pressure resistance of the refrigerant pipe can be increased.

Here, it is preferable to use a metal jacket made of aluminum and having a heater and a refrigerant pipe embedded therein by a vacuum precision casting method. The vacuum precision casting method is a technique for removing air bubbles in Al at the time of casting by pressing under reduced pressure and producing an Al casting having no problem in strength, etc. This is because the jacket can easily incorporate therein a high-pressure-resistant refrigerant pipe and a heater. The refrigerant pipe is preferably made of aluminum or copper. If such a metal having high thermal conductivity is used, heat exchange (heat conduction) between the refrigerant supplied to the refrigerant pipe and the metal jacket is rapid. become.

According to a fourth aspect of the present invention, there is provided a wafer temperature adjusting method.
Using the wafer stage according to claim 1, a wafer is placed on the electrostatic chuck, and the heater is energized to perform heating, and a gas refrigerant is supplied to the refrigerant pipe from a cooling unit, and In this case, the solution to the problem is to adjust the temperature of the wafer by adjusting the amount of electricity supplied to the heater and the flow rate of the gas refrigerant to the refrigerant pipe.

According to this temperature adjusting method, the heat transfer from the metal jacket to the dielectric is made faster, and thus the temperature is adjusted using the wafer stage which has made the heat transfer to the wafer faster. Since the temperature can be changed over time, and the temperature of the wafer is adjusted by the heater and the refrigerant pipe embedded in the metal jacket,
Since the temperature can be adjusted using both heating and cooling, the wafer temperature can be stabilized.

According to a fifth aspect of the present invention, there is provided a dry etching apparatus including the wafer stage according to the first aspect. According to this dry etching apparatus, since the wafer stage is provided, the temperature can be changed in a short time as described above by using the wafer stage. When it is desired to perform a plurality of steps of etching at different temperatures as described above, it becomes possible to perform these etching processes without greatly reducing the throughput.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIG. 1 is a view showing one embodiment of a wafer stage according to the present invention. In FIG. 1, reference numeral 1 denotes a wafer stage. The wafer stage 1 is configured by mounting and fixing an electrostatic chuck 3 on a metal jacket 2.

The metal jacket 2 is made of aluminum formed by a vacuum precision casting method, and has a heater 4 and a refrigerant pipe 5 embedded therein. The heater 4 is formed of a large-sized, large-capacity sheathed heater corresponding to the area (bottom area) of the metal jacket 2 and is connected to a power supply via wiring (not shown). The refrigerant pipe 5 is made of a metal having a high thermal conductivity, such as Al or Cu, connected to a cooling means described below. The refrigerant pipe 5 allows the gas refrigerant supplied from the cooling means to flow into the metal jacket 2, and The purpose is to cause heat exchange between the heat exchanger.

Here, in order to obtain such a metal jacket 2, a vacuum precision casting method is employed as described above. This vacuum precision casting method is a method in which a heater 4 and a refrigerant pipe 5 are put into a mold, molten Al is poured into the mold, and press-casting is performed under reduced pressure. This is a technique that eliminates air bubbles inside and makes it possible to produce an Al casting having no problem in strength or the like. Then, by being manufactured by such a vacuum precision casting method, air bubbles do not remain in the metal jacket 2 between the metal portion and the heater 4 and between the metal portion and the refrigerant pipe 5, respectively. Therefore, in the obtained metal jacket 2, heat exchange (heat conduction) between the heater 4 and the metal part and between the refrigerant pipe 5 and the metal part becomes faster.

That is, according to this vacuum precision casting method,
Since there is no possibility that bubbles or the like are generated in the metal as in a normal casting method, the heater 4 and the refrigerant pipe 5 prepared in advance can be easily integrated with the metal (Al), and the pressure resistance of the refrigerant pipe 5 can be improved. Therefore, the same quality as that obtained by cutting out the Al solid can be obtained.

The electrostatic chuck 3 includes a disk-shaped dielectric 6,
This is constituted by an electrode 7 provided on the lower surface thereof. The dielectric 6 is made of an insulating material having a high thermal conductivity, in this example, aluminum nitride (AlN) (thermal conductivity: 0.2
35 [cal / cm · sec · ° C]). In addition, instead of aluminum nitride, sapphire (thermal conductivity; 0.1 [cal / cm · sec · ° C.]) or alumina (thermal conductivity; 0.05 [cal / cm · sec · ° C.]) is used as the dielectric 6. ]) Can be used.

The electrode 7 is made of a conductor. In this example, a brazing layer for fixing the dielectric 6 on the metal jacket 2, that is, provided between the metal jacket 2 and the dielectric 6. It is formed of a brazing material having a thickness of about 0.5 mm. Specific examples of the brazing material include alloys of titanium, tin, antimony, and magnesium. The electrode 7 is connected to a high-voltage power supply via a wiring (not shown in FIG. 1) so that when a DC voltage is applied to the electrode 5, the dielectric 6 exerts an attractive force. Has become.

The electrostatic chuck 3 has a dielectric 6
A pusher pin (not shown) for pushing up a wafer mounted and held thereon is embedded, and the pusher pin is further provided with a retracting mechanism (e.g., a projection mechanism which projects the projection onto the surface of the dielectric 4 or buries it under the surface. (Not shown) is connected.

Next, as one embodiment of the dry etching apparatus of the present invention, a dry etching apparatus provided with the wafer stage 1 shown in FIG. 1 will be described with reference to FIG.
In FIG. 2, reference numeral 10 denotes a dry etching apparatus (hereinafter, referred to as a dry etching apparatus).
The etching apparatus 10 includes a helicon wave plasma generation source having two RF antennas installed therein and a stage movable in a vertical direction, and includes a diffusion chamber 11. And an RF antenna 1 provided above the diffusion chamber 11.
2, 12; an RF antenna 13 installed in a loop on the top plate 11a of the diffusion chamber 11; and a cusp magnetic field provided outside the lower part of the diffusion chamber 11 to suppress the loss of electrons on the wall. And a multi-pole magnet 14.

The RF antennas 12, 12 are provided around the outside of a bell jar 15 formed of a cylindrical quartz tube having a diameter of 350 mm and formed on the upper portion of the diffusion chamber 11, and the plasma of M = 1 mode is provided. The antenna has a standing antenna shape. A solenoid coil assembly 16 including an inner coil and an outer coil is disposed outside the RF antennas 12 and 12. The inner peripheral coil of the solenoid coil assembly 16 contributes to the propagation of the helicon wave, and the outer peripheral coil contributes to the transport of the generated plasma. RF antenna 1
A power supply 18 is connected to 2 and 12 via a matching network 17, and a power supply 20 is connected to the RF antenna 13 via a matching network 19.

The wafer stage 1 for supporting and fixing a wafer W serving as a sample is provided in the diffusion chamber 11, and an exhaust port 21 for exhausting gas in the diffusion chamber 11 is provided with a vacuum pump or the like. Is connected to negative pressure means (not shown). Wafer stage 1
Is connected to a bias power supply 22 for controlling ion energy incident on the wafer W.

The chiller 25 is connected to the metal jacket 2 of the wafer stage 1 via pipes 23 and 24.
And a fluorescent fiber thermometer 26 for measuring the temperature of the wafer W is connected. Chiller 25
Is a low temperature (for example, −100) made of Freon, He gas, or the like.
(Lower than 0 ° C.) gas refrigerant is supplied into the refrigerant pipe 5 of the metal jacket 2 of the wafer stage 1 through the pipe 23, and the refrigerant returned from the refrigerant pipe 5 is received through the pipe 24, and is supplied to the predetermined position. The wafer W is cooled to a temperature, and the wafer W supported and fixed on the wafer stage 1 is cooled by circulating the gas refrigerant in the refrigerant pipe 5 in this manner. That is, the chiller 25 and the pipe 2
3, 24, and further chiller 25 from metal jacket 2
The cooling means in the present invention is constituted by the gas refrigerant circulated through the cooling medium.

An electronic control valve 27 capable of operating at a very low temperature is provided in a pipe 23 connected to the chiller 25, and a bypass pipe 28 between the pipe 23 and the pipe 24 is also operated at a very low temperature. An electronic control valve 27 is provided, which can be operated. Here, the degree of cooling of the wafer W is determined by the chiller 25.
Is controlled by the flow rate of the refrigerant supplied from the controller. That is, in order to cool the metal jacket 2 of the wafer stage 1 to cool the temperature of the wafer W to a desired temperature, the temperature detected by the fluorescent fiber thermometer 26 is detected by the control device (PID controller) 29, The controller 29 controls the degree of opening and closing of the electronic control valves 27 and 27 from the difference between the preset temperature of the wafer W and the gas refrigerant flow rate determined in advance through experiments and calculations. In FIG. 2, an etching gas introduction hole,
The details of the device such as a gate valve are not shown.

Next, based on an example of a dry etching method using such an etching apparatus 10, an example of a method of using the wafer stage 1 shown in FIG. 1 and an example of a method of adjusting the temperature of a wafer in the present invention will be described. 3 (a) ~
This will be described with reference to FIG. This processing method is a method of processing W polycide by a two-step etching process. That is, this example, W consisting of 3 silicon substrate (wafer W) as shown in (a) a polysilicon layer 32 on the SiO ₂ film 31 on 30 and WSi _x layer 33
A sample in which a polycide is formed, and a photoresist pattern 34 is further formed thereon, is processed by etching the W polycide to form a pattern shape corresponding to the photoresist pattern 34. The etching is a second step in which overetching is performed at a low temperature.

[0030] First, the main etching of the first step by a normal temperature (20 ° C.) under the following conditions, and a WSi _x layer 33 and the polysilicon layer 32 as shown in FIG. 3 (b),
The polysilicon layer 32 is removed by etching until a part thereof is left. First step (main etching) Etching gas; Cl ₂ / O ₂ 50/10 sccm pressure; 5 mTorr Source power 1 (RF antenna 4); 1500 W (13.56 Hz) Source power 2 (RF antennas 3 and 3); 1500 W ( 13.56 Hz) RF bias; 100 W Wafer temperature; 20 ° C. Note that the wafer temperature is adjusted by heating the heater 4 in the metal jewelry 2 provided on the wafer stage 1, and by supplying gas refrigerant from the chiller 25. The metal jacket 2 is also cooled by the refrigerant pipe 5 by the circulation, and the wafer temperature is finely adjusted by the cooling control by the control device 29 described above.

Next, in order to perform an over-etching process in a second step following the first step, the discharge in the etching apparatus 10 is once stopped, and the gas remaining in the diffusion chamber 11 is exhausted from the exhaust port 21. Then, an etching gas (the same gas as in the first step is used in this example) used for a second step described later is introduced into the diffusion chamber 11, and the gas is stabilized to maintain a constant pressure in the diffusion chamber 11. Adjust to Also, during such a series of operations, that is, immediately after the end of the etching process of the first step, the power supply to the heater 4 is stopped, and the electronic control valve of the bypass pipe 28 in the cooling system by the chiller 25 is used. 27, the electronic control valve 27 of the refrigerant pipe 23 is fully opened, and a gas refrigerant at −140 ° C. is supplied from the chiller 25 into the refrigerant pipe 5 of the metal jacket 2 to rapidly cool the wafer W.

Then, by such rapid cooling, the wafer W reached -30 ° C., which is an etching temperature described later, in a short time of about 30 seconds. This is because, as described above, in the wafer stage 1 of the present invention, the electrostatic chuck 3 on the metal jacket 2 is joined to the metal jacket 2 by the electrode 7 made of the brazing material. This is because heat conduction from the fluid to the dielectric 6 is accelerated, and since the refrigerant pipe 5 has a high pressure resistance as described above, a high-pressure gas refrigerant, This is because a large amount of cold heat can be transmitted to the wafer W through the metal jacket 2 in a short time.

At this time, the above-described series of operations, that is, a series of operations such as exhausting the residual gas in the diffusion chamber 2 after the discharge is cut off, and introducing new etchin gas to stabilize the same are performed by rapid cooling. Since the time required for the rapid cooling is equal to or longer than the required time, the time required for the rapid cooling does not cause a delay in the time required for the etching process of the wafer W. The rapid cooling allows the dielectric 6 of the wafer stage 1 and the electrostatic chuck 2 to be removed.
No damage or the like occurred.

Subsequently, the discharge is performed again to perform a second step of over-etching at a low temperature (−30 ° C.) under the following conditions, and the over-etching is performed in a state exposed on the SiO ₂ film 31 as shown in FIG. A part of the remaining polysilicon layer 32 is removed by etching. Second step (over-etching) Etching gas; Cl ₂ / O ₂ 50/10 sccm pressure; 5 mTorr Source power 1 (RF antenna 4); 2500 W (13.56 Hz) Source power 2 (RF antennas 3 and 3); 2500 W ( 13.56 Hz) RF bias; 20 W Wafer temperature; -30 ° C.

When the over-etching process is performed in this manner, since the etching process is a process under low-temperature cooling, the radical reaction can be suppressed by lowering the temperature even if the formed sidewall protective film is thin, Therefore, it becomes possible to withstand an excessive radical attack, and the first
Even if the applied bias to the wafer W is reduced from 100 W to 20 W as compared with the step, the occurrence of undercut or notching can be suppressed. Therefore, without affecting the shape even under 100% overetching, while ensuring a selectivity of 100 or more with respect to the underlying SiO ₂ ,
As shown in FIG. 3C, a sufficient anisotropic shape can be ensured.

After the completion of the etching process in the second step, the processed wafer is unloaded and then the new wafer W is loaded in order to continuously and repeatedly perform the same process on the new wafer W with the same processing apparatus. Before the heating, the heater 4 of the wafer stage 1 is energized, and in the cooling system using the chiller 25, the electronic control valve 27 of the bypass pipe 28 is fully opened and the electronic control valve 27 of the refrigerant pipe 23 is fully closed. Metal jacket 2 from chiller 25
The wafer stage 1 was rapidly heated by, for example, stopping supply of the gas refrigerant to the wafer stage, and the temperature was returned to 20 ° C., which was the temperature in the first step.

At this time, the time required for the temperature adjustment by the heating was about 20 seconds. This is because, as described above, in the wafer stage 1 of the present invention, the heat conduction from the metal jacket 2 to the dielectric 6 becomes faster, and as described above, the heater 4 has a large, large-capacity sheath. This is because a large amount of heat can be transmitted to the wafer W via the electrostatic chuck 3 in a short time by using the heater. The rapid heating did not cause breakage or the like of the wafer stage 1 or the dielectric 6 of the electrostatic chuck 2.

Next, another example of the dry etching processing method using the etching apparatus 10 shown in FIG.
This will be described with reference to (a) to (c). This processing method
A method of processing a contact hole by etching, in FIG. 4 the silicon substrate (wafer W) as shown in (a) sample to form a photoresist pattern 42 is formed on the SiO ₂ layer 41 on 40, SiO ₂ layer 41 is processed by etching to form a pattern corresponding to the photoresist pattern 42. As a first step, just etching (main etching) is performed at room temperature.
In the subsequent second step, over-etching is performed at a low temperature.

First step (just etching) Etching gas; C ₄ F ₈ / O ₂ 50/10 sccm pressure; 5 mTorr Source power 1 (RF antenna 4); 2500 W (13.56 Hz) Source power 2 (RF antenna 3, 3); 2500 W (13.56 Hz) Pulse ON / OFF; 10 μsec / 30 μsec RF bias; 500 W Wafer temperature: 20 ° C. Note that the wafer temperature adjustment here is the same as in the previous example. The heater 4 provided in the metal jacket 2 and the cooling by the gas refrigerant from the chiller 25 were used in combination.

Next, in order to perform the second step of the over-etching process following the first step, the discharge in the etching apparatus 1 is once stopped, and the gas remaining in the diffusion chamber 11 is exhausted from the exhaust port 21. Then, an etching gas used in the second step described later (the same gas as in the first step is used in this example) is introduced into the diffusion chamber 11, and the gas is stabilized to maintain a constant pressure in the diffusion chamber 11. Adjust to Also, during such a series of operations, that is, immediately after the end of the etching process of the first step, the power supply to the heater 4 is stopped in the same manner as in the previous example, and the bypass piping in the cooling system by the chiller 25 is used. 28 electronic control valves 27
Is fully closed, the electronic control valve 27 of the refrigerant pipe 23 is fully opened, and a gas refrigerant at −140 ° C. is supplied from the chiller 25 into the refrigerant pipe 5 of the metal jacket 2 to rapidly cool the wafer W.

As a result, the wafer W reached an etching temperature of -50 ° C., which will be described later, in a short time of about 30 seconds similarly to the previous example by such rapid cooling. Therefore, even in this example, a series of operations such as exhausting the gas remaining in the diffusion chamber 11 after the discharge is cut off, and introducing new etchin gas to stabilize the gas,
Since the time required for the rapid cooling is longer than the time required for the rapid cooling, the time required for the rapid cooling does not become a factor that delays the time required for the etching process of the wafer W.

Subsequently, the discharge is performed again to perform a second step of over-etching at a low temperature (−50 ° C.) under the following conditions, and as shown in FIG. A part of the SiO ₂ layer 41 is removed by etching to form a contact hole 43. - second step (overetching) etching _{gas; C 4 F 8 / O 2} 50 / 10sccm pressure; 5 mTorr source power 1 (RF antenna 4); 2500W (13.56 Hz) source power 2 (RF antenna 3,3); 2500 W (13.56 Hz) pulse ON / OFF; 10 μsec / 30 μsec RF bias; 200 W wafer temperature; −50 ° C.

When the over-etching process is performed in this manner, since this etching process is a process under low-temperature cooling, even if the side wall protective film formed is thin as in the case of the previous example, radical reduction is caused by lowering the temperature. The reaction can be suppressed, and therefore, it can withstand an excessive radical attack.
Even if the bias applied to the sample is set to 00W, the occurrence of undercut or notching can be suppressed. Therefore, for example, when the temperature is lowered from the just etching in the first step, the organic polymer is deposited on the side wall of the contact hole to be formed, and the shape of the contact hole is tapered, so that a fine hole opening cannot be formed. By lowering the temperature only for over-etching as in this example, this problem is solved and the silicon substrate 4 is removed.
4 (c), while ensuring a selectivity of 100 or more with respect to 0.
As shown in FIG.
3 can be formed with good reproducibility.

After the completion of the etching process in the second step, the processed wafer W is unloaded so that the same process can be continuously and repeatedly performed on a new wafer W by the same processing apparatus as in the previous example. Thereafter, before a new wafer W is loaded, the heater 4 of the wafer stage 1 is energized, and the bypass pipe 2 in the cooling system by the chiller 25 is used.
The electronic control valve 27 of FIG.
3, the electronic control valve 27 is fully closed, and the supply of the gas refrigerant from the chiller 25 to the metal jacket 2 is stopped.
The temperature in the step was returned to 20 ° C. At this time, the time required for the temperature adjustment by this heating was about 25 seconds.
This is because, in the wafer stage 1 of the present invention, the heat conduction from the metal jacket 2 to the dielectric 6 is accelerated similarly to the previous example, and the heater 4 is large and has a large capacity as described above. This is because a large amount of heat can be transmitted to the wafer W via the electrostatic chuck 3 in a short time by using the sheathed heater.

As described above, in the etching apparatus 10 of the present invention, a gas refrigerant, which can be easily supplied in a large amount, is used as the cooling medium, and is supplied to the refrigerant pipe 5 in the metal jacket 2 so that the wafer stage 1 Is cooled by the large-capacity heater 4 embedded in the metal jacket 2 so that the wafer W can be rapidly cooled as compared with the cooling method using a liquid as a coolant. In addition, the wafer W can be rapidly heated by the large-capacity heater 4, so that the temperature of the wafer W can be adjusted to a desired temperature in a short time.

In addition, since the temperature of the wafer W can be adjusted in a short time in this manner, the main etching at room temperature and the over-etching at low temperature can be applied to W polycide having different vapor pressures of the reaction products as described above. By performing the etching process in the two steps described above, it is possible to ensure both a high selectivity and an anisotropic shape, that is, high-precision fine processing. Moreover, since each step is performed by the same etching apparatus 10 and the wafer temperature can be easily changed between the steps in a short time by using the wafer stage 1, it is possible to stop the discharge between the steps and to reduce the etching gas. The temperature can be changed within or close to the time required for a series of operations such as changing, and therefore, the dry etching process including a plurality of steps can be quickly performed without lowering the throughput.

Further, in the wafer stage 1 of the present invention, the heater 4 and the refrigerant pipe 5 embedded in the metal jacket 2 enable rapid heating and rapid cooling, so that a long time is required. The temperature of the wafer W can be switched in a short period of time, such as about 20 to 40 seconds, so that etching at different temperatures can be performed almost continuously, and the advantages of low-temperature etching can be fully utilized.

[0048]

As described above, in the wafer stage according to the present invention, since the electrodes are formed by the brazing layer for fixing the dielectric to the metal jacket, the electrode is formed between the dielectric and the electrode. The electrode can be formed to be thin while ensuring the bonding, and the electrode is made of brazing material,
That is, since the metal or alloy has good thermal conductivity, heat conduction from the metal jacket to the dielectric and further from the dielectric to the wafer W can be accelerated. Also, since the heater is embedded inside the metal jacket, the metal jacket can be made larger than the electrostatic chuck, for example, compared to incorporating the heater in an electrostatic chuck. Therefore, rapid heating can be enabled by increasing the capacity of the heater. Further, since the refrigerant pipe is embedded in the metal jacket, the refrigerant pipe is reinforced by the metal jacket, and the refrigerant pipe has high pressure resistance. , A high-pressure gas refrigerant, that is, a large amount of gas refrigerant, can be flown, thereby enabling rapid cooling of the wafer. Further, since the dielectric is fixed to the metal jacket by brazing and the brazing layer and the dielectric are used as an electrostatic chuck, the wafer stage itself has a simple configuration, and therefore, the wafer stage has a long-term reliability. The property is sufficiently secured.

According to the temperature adjusting method of the present invention, the temperature is adjusted by using the wafer stage in which the heat conduction from the metal jacket to the dielectric material is quick, and thus the heat conduction to the wafer is quick. Therefore, the temperature can be changed in a short time, and further, since the temperature of the wafer is adjusted by the heater and the refrigerant pipe embedded in the metal jacket, the temperature is adjusted by using both heating and cooling. Thus, the wafer temperature can be stabilized.

Since the dry etching apparatus of the present invention includes the wafer stage, the temperature can be changed in a short time as described above by using the wafer stage. When it is desired to perform multiple steps of etching at different temperatures, such as etching at a time, these etching processes can be performed without greatly lowering the throughput, thereby achieving high-precision fine processing, high selectivity, and Can be realized.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of a wafer stage of the present invention.

FIG. 2 is a schematic configuration diagram of a dry etching apparatus of the present invention.

3 (a) to 3 (c) are cross-sectional views of essential parts for describing an example of a dry etching method using the etching apparatus shown in FIG. 2 in the order of processing.

4 (a) to 4 (c) are cross-sectional views of essential parts for explaining another example of the dry etching method using the etching apparatus shown in FIG. 2 in the order of processing.

[Explanation of symbols]

1 wafer stage 2 metal jacket 3
Electrostatic chuck 4 Heater 5 Refrigerant piping 6 Dielectric 7 Electrode 10 Dry etching unit 23, 24 Piping
25 Chiller W Wafer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinsuke Hirano 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Kinya Miyashita Kinoshita 802 Shimosakunobu 802 Takatsu-ku, Kawasaki City, Kanagawa Prefecture Inside the science (72) Inventor Yoshiaki Tatsumi 802 Shimosakunobu, Takatsu-ku, Kawasaki-shi, Kanagawa

Claims (5)

[Claims] 1. An electrostatic chuck having a dielectric made of an insulating material and an electrode made of a conductor, and a metal jacket joined to the electrostatic chuck, wherein the electrode is made of a metal made of a metal. A wafer stage formed by a brazing layer for fixing to a jacket, wherein the metal jacket is formed by embedding a refrigerant pipe connected to a heater and a cooling unit therein. 2. The wafer stage according to claim 1, wherein said metal jacket is made of aluminum and formed by vacuum precision casting with a heater and a refrigerant pipe embedded therein. 3. The wafer stage according to claim 1, wherein said refrigerant pipe is made of aluminum or copper. 4. An electrostatic chuck having a dielectric made of an insulating material and an electrode made of a conductor, and a metal jacket joined to the electrostatic chuck, wherein the electrode is made of a metal made of metal. A wafer is mounted on the dielectric of a wafer stage formed by a brazing layer for fixing to a jacket, wherein the metal jacket is formed by embedding a refrigerant pipe connected to a heater and cooling means therein. And applying heat to the heater to perform heating and supplying gas refrigerant from the cooling means to the refrigerant pipe, and at this time, adjusting the amount of power supplied to the heater and the flow rate of gas refrigerant to the refrigerant pipe. And adjusting the temperature of the wafer. 5. An electrostatic chuck having a dielectric made of an insulating material and an electrode made of a conductor, and a metal jacket joined to the electrostatic chuck, wherein the electrode is made of a metal made of metal. The metal jacket is formed by a brazing layer for fixing to a jacket, and the metal jacket includes a wafer stage formed by embedding a refrigerant pipe connected to a heater and cooling means therein. Dry etching equipment.