JP3157551B2 - Workpiece mounting device and processing device using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting apparatus for mounting an object to be processed such as a wafer in a vacuum apparatus such as a plasma etching apparatus and a processing apparatus using the same.

[0002]

2. Description of the Related Art In a plasma etching apparatus, for example, a support table called a susceptor is used to support a wafer. Since the temperature of the wafer is raised to a high temperature by the plasma during the etching process, the susceptor is provided with a temperature control mechanism for cooling the wafer to a predetermined temperature.

[0003] In recent years, the diameter of wafers has been increasing, and the types of wafer diameters have also increased depending on the types of wafers. Therefore, it is necessary to use susceptors adapted to wafers of various sizes. An apparatus capable of using a susceptor suitable for such various wafers is disclosed in Japanese Patent Application Laid-Open No. 59-115521.

In addition, a wafer support table used for plasma etching, for example, needs to be replaced as a consumable because the surface side is damaged.
Further, for example, when an electrostatic chuck sheet is provided, replacement of the electrostatic chuck is also required.

For the above reasons, the support table can be divided into a fixed part and a separation part, and the replacement operation can be performed only by removing the separation part according to the size of the wafer or when the surface is damaged. It is desired. That is, when the support table is divided into two, a fixed portion having a temperature control function can be permanently provided, and only a separation portion can be prepared for a type corresponding to a wafer size, and can be adapted to various sizes. When the surface of the support table or the electrostatic chuck is replaced, only the separation portion needs to be removed, so that the replacement operation can be easily performed.

[0006]

However, when the support table has a divided structure, the separation and the joint between the fixed part and the fixed part always have a gap or a state where dust is trapped in the gap. Therefore, the heat transfer characteristics between the fixed portion and the separation portion are deteriorated. For this reason,
There is a problem that the temperature of the object cannot be efficiently adjusted. In particular, in the case of a support table used in a vacuum processing device such as an etching device, since the space between the fixed portion and the separation portion is also in a vacuum state, heat conduction by gas is not performed, and bolt fastening between the two is performed. Only solid contact heat conduction near the part can be expected. At this time, since the bolted portion is present at the periphery of the support table, the heat transfer path to the center becomes long, and effective heat transfer cannot be expected in the center, and it is extremely difficult to uniformly control the temperature of the wafer. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide a two-part type processing target capable of effectively adjusting the temperature of a processing target supported thereon. An object of the present invention is to provide a body mounting device.

Another object of the present invention is to provide a processing apparatus using such a mounting device.

[0009]

A mounting apparatus according to the present invention comprises a first mounting table having a temperature control function, a second mounting table provided on the first mounting table, An electrostatic chuck provided on the mounting table 2 for sucking and holding the object to be processed;
The first step of introducing gas between the contact surfaces of the first and second mounting tables .
1, the gas introduction unit, the object to be processed, and the electrostatic chuck
And a second gas introduction part for introducing a gas between the two . The first and second mounting tables are flat.
And the outer circumference of the space between the first and second mounting tables.
Is hermetically sealed with an O-ring along the
Through the first gas introduction portion into the gap region thus formed.
It is preferred to introduce the body.

According to a third aspect of the present invention, there is provided a processing apparatus, comprising: a vacuum chamber maintained at a predetermined degree of vacuum; a processing object mounting apparatus according to claim 1 or 2 disposed in the vacuum chamber; Processing means for performing appropriate processing on the body.

[0011]

According to the present invention, the mounting table holding the electrostatic chuck has a divided structure, so that when the size of the object to be processed is changed or when consumables are replaced, It can be addressed only to replace only one of the mounting table, moreover, by the introducing the gas <br/> body through the first gas introduction section between the contact surfaces of both the mounting table, the gap therebetween , The heat conductivity of the gas can be increased, and a predetermined temperature control operation can be ensured. Furthermore, the object to be processed and the electrostatic
The gas is also introduced between the chuck and the chuck through the second gas inlet.
Temperature control accuracy of the object
Layer enhanced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is applied to an electrostatic chuck type support table used in a plasma etching apparatus will be described in detail.

FIG. 1 is a schematic configuration diagram of a plasma etching apparatus to which a support table according to one embodiment of the present invention is applied. The apparatus includes a vacuum chamber 10, a support table 20 provided in the chamber 10 and serving as a first electrode for supporting the wafer 1, a second electrode provided above the chamber 10, and a vacuum chamber 10. It includes a magnet section 30 provided outside and an RF power supply 40.

The vacuum chamber 10 has an upper chamber 11 and a lower chamber 12. An exhaust port 13 is provided at a lower portion of the side wall of the upper chamber 11, and the inside of the vacuum chamber 10 is exhausted by an exhaust pump (not shown) connected to the exhaust port 13. The vacuum chamber 10 is designed to be able to reduce the pressure to, for example, about 10 ⁻⁶ Torr. The upper wall of the upper chamber 11 is provided with a plurality of gas inlets 14 for introducing an etching gas, and the inlets 14 are provided with a gas for supplying an etching gas from a gas supply source (not shown). The supply pipe 14a is connected.

The support table 20 is installed on the lower chamber 12 via an electrically insulating ceramic member 15, and the lower chamber 12 and the support table 20 are electrically insulated. The support table 20 includes an upper member 21 having a wafer support portion, and a lower member 2 having a coolant flow path for adjusting the temperature of the wafer, for example, a liquid flow path 23.
And 2. The detailed structure of the support table 20 will be described later.

The high frequency power supply 40 is connected to the upper member 21 of the support table 20, and the upper chamber 11 is installed. Therefore, when high-frequency power is supplied between the first and second electrodes, the upper wall of the upper chamber 11 functions as an upper electrode, and the upper member 21 functions as a lower electrode, and a plasma Occurs.

The magnet section 30 has a role of applying a magnetic field in a direction orthogonal to an electric field formed between the electrodes, and includes a horizontally provided support member 31 and a permanent magnet 32 supported by the support member 31. And a motor 33 for rotating these in the direction of the arrow in the figure.

In such a magnetron plasma etching apparatus, an etching gas is introduced into the chamber 10 and high frequency power is applied between the upper electrode and the lower electrode while the rotating permanent magnet 32 rotates between the electrodes. Since a magnetic field is applied, electrons existing between the electrodes perform cyclonic motion due to the orthogonal electromagnetic field, and the number of times of ionization of the molecule increases due to the collision of the electron with the molecule, and 10 ⁻² Torr
Even at a relatively low pressure, a high etching rate of 1 μm / min can be obtained. Accordingly, there is an advantage that the processing per one sheet can be performed in a short time, and the reliability of etching is improved. Further, since the average energy of ions is low, damage to the wafer is small.

Next, the support table 20 for a wafer as an object to be processed will be described in detail. FIG. 2 is a sectional view showing the support table 20 in detail. This support table 2
Reference numeral 0 has the upper member 21 and the lower member 22 as described above, and on the upper surface of the upper member 21 is provided an electrostatic chuck 24 for attracting the wafer by electrostatic force (Coulomb force). I have. The chuck 24 is a mechanism that conducts through the plasma when the plasma is generated, for example, and generates an electrostatic attraction force. And the lower member 22 is permanently installed,
On the other hand, the upper member 21 and the electrostatic chuck 24 can be replaced.

The upper member 21 has a disk shape having a step on the outer periphery, and the lower member 22 has a simple disk shape. In the vicinity of the outer periphery of the upper member 21, bolt insertion holes 28 are formed at equal intervals along the outer periphery, and the lower member 22 has screw holes 28 at positions corresponding to the bolt insertion holes 28.
a is formed, a bolt 29 is inserted into the insertion hole 28, and the upper member 21 and the lower member 22 are fastened by the bolt 29. Then, by removing the bolt 29, the upper member 21 can be removed from the lower member 22.

The electrostatic chuck 24 is, as shown in FIG.
Two insulating sheets (for example, polyimide sheets) 24a,
24b, and a conductive sheet 24c formed of copper or the like interposed therebetween. After the wafer 10 is mounted on the electrostatic attraction sheet 24, a high voltage is applied between the wafer 1 and the conductive sheet 24c from a power source (not shown) via plasma, so that the wafer 1 is driven by Coulomb force. 1 is adsorbed. By this electrostatic chuck 24, the upper member 21 and the lower member 22 are electrically insulated.

As described above, the lower member 22 is provided with the annular liquid communication channel 23.
Is connected to a liquid introduction path 23a and a liquid outlet path 23b, and the temperature of the wafer 1 is adjusted by supplying a liquid having a predetermined temperature to the liquid flow path 23 at an appropriate flow rate.
In this case, the temperature of the liquid is appropriately set according to the type of the wafer to be processed. That is, at the time of the etching operation, for example, when an unnecessary reaction other than the etching chemical reaction occurs due to the heat of the plasma and the predetermined etching is difficult, a cooling medium such as about −25 ° C. The wafer temperature is cooled and maintained at around -15 ° C. by circulating the antifreeze. Depending on the etching process, for example, it is appropriate that the temperature of the wafer 1 is about 70 to 80 ° C. In such a case, a heating medium such as hot water is circulated through the liquid passage 23 so that the wafer 1 is heated. Temperature can be controlled.

The lower member 22 is provided near the outer periphery of the upper surface thereof.
An O-ring groove 26a is formed along the outer periphery, and a gas-filling ring groove 2a is formed inside the O-ring groove 26a along the outer periphery.
5a are formed. The gas introduction passage 25 is provided in the groove 25a.
Is connected to a gas supply source (not shown), and a control mechanism, which will be described later, and a gas for heat transfer, such as He, Ar, or O ₂ , is supplied to the groove 25 a through the introduction path 25 and is supplied to the upper member 21. The gas is interposed between and the lower member 22. In this embodiment, the O-ring groove 26a has O
A ring 26 is fitted to prevent heat transfer gas from leaking from between the upper member 21 and the lower member 22. If it is slight, it may leak.

The upper member 21 and the lower member 2 of this heat transfer gas
2 is controlled by, for example, a mechanism as shown in FIG. The gas introduction path 25 is provided with a gas supply pipe 50.
Are connected so as to branch upward on the way. A regulator 52 is provided on the IN side of the gas supply pipe 50.
And a throttle valve 54, and a throttle valve 5 is provided on the OUT side thereof.
6 are provided. The gauge pressure measured by the regulator 52 is fed back to a valve driving unit 58 that drives the OUT-side throttle valve 56, and the OUT-side throttle valve 56 is controlled so that the measured gauge pressure is always constant. Open / close drive is performed. Further, the valve may be adjusted while checking the gauge pressure without using the valve drive unit 58.

In the case of a conventional support table that does not allow a heat transfer gas to flow, there is a gap between the upper member 21 and the lower member 22 due to a difference in smoothness, a gap due to surface roughness, and the like. Further, a gap or the like caused by intrusion of dust is generated. Even if the temperature is adjusted on the lower member 22 side in a state where such a gap is generated, since the inside of the vacuum processing chamber is evacuated, the heat conduction by the gas between the upper member 21 and the lower member 22 is performed. Almost no heat is generated, and only heat conduction due to solid contact around the fastening bolt 29 between these two members can be expected.

On the other hand, as in the present invention, the upper member 2
When a gas for heat transfer is held between the first member and the lower member 22 at a predetermined pressure, the heat transfer characteristics between the two members can be improved, and the wafer as the object to be processed can be efficiently heated. Can be adjusted.

The type of gas used as the heat transfer gas is not particularly limited. However, for that purpose, gases having high thermal conductivity are preferred, and He, O ₂ , Ar, N _{2 and the} like are preferred. Of these, He is particularly preferred.

The effect can be obtained if the pressure of the heat transfer gas is not less than a certain value. For this purpose, the gas pressure is controlled as described above.
When the pressure of the gas exceeds a specific value, the heat conduction by the gas does not depend much on the gas pressure, but largely depends on the gap distance between the upper member 21 and the lower member 22.
That is, the effect of the heat transfer gas increases as the gap between these members decreases. Therefore, by minimizing the gap between these members as much as possible, heat conduction by the gas is improved, and temperature control can be performed with high accuracy. By precisely finishing the mating surfaces of these members, the gap can be reduced to, for example, 10 μm or less, whereby heat is transmitted with high efficiency, and high-precision temperature control is realized.

FIG. 5 shows the effect of such a heat transfer gas. FIG. 5 shows He and O ₂ as heat transfer gases.
The horizontal axis indicates the pressure between the upper and lower members of the heat transfer gas, and the vertical axis indicates the temperature difference between the upper member 21 and the lower member 22. It is a graph which shows an example. Here, the temperature at the point A of the upper member 21 and the temperature at the point B of the lower member 22 shown in FIG. 2 are measured, and the temperature difference between them is taken. Note that an antifreeze at −25 ° C. is used as a refrigerant flowing through the lower member. The pressure in the chamber 10 is 3.5 × 10 ⁻³ Torr.

As shown in this figure, the temperature difference was 15 ° C. or more before the gas was introduced.
Thus, it can be seen that the temperature difference is reduced. Also,
Gas pressure above 100 Torr, more notably 150 Torr
From the above , it can be seen that the temperature reduction effect is saturated. The effect of the temperature decrease differs depending on the gas. In the case of O2 gas, the temperature difference is reduced only to about 10 ° C.
It is confirmed that the temperature difference is reduced to about 4 ° C. for He gas.

Further, a gas for heat transfer is also supplied between the wafer 1 and the electrostatic chuck 24 from the gas introduction path 27, whereby the temperature control accuracy of the wafer 1 is further improved. . Although this gas is not particularly limited, He, He is the same as the above-mentioned heat transfer gas.
O ₂ , Ar, N _{2 and the} like are preferred.

Next, the operation of the thus-configured magnetron etching apparatus will be described.

First, the wafer to be etched is evacuated from the load lock chamber to a predetermined degree by a robot, and then the wafer 1 is handled on the electrostatic attraction sheet 24. A high voltage of, for example, 2K volts is applied between the sheet 24c and the electrostatic chuck. When plasma is generated in a process described later, static electricity is induced in the sheet 24 due to conduction through the plasma, and the wafer 1 is electrostatically attracted onto the electrostatic attracting sheet 24 by Coulomb force.

Next, the pressure in the vacuum chamber 10 is set to 0.1 mT
orr to 10 mTorr, e.g., about 1 × 10 ^-3 Torr.
₂ gas, Cl gas, and SF ₆ gas are introduced at a flow rate of, for example, 50 cc / s in terms of normal temperature and normal pressure. In this state, RF power is supplied from the high frequency power supply 40 between the upper wall of the upper chamber 11 as the upper electrode and the upper member 21 as the lower electrode. Thus, a magnetron discharge is generated by the orthogonal electromagnetic field formed between the electrodes, and plasma is generated. As a result, radicals and ions are generated, and the surface of the wafer 1 is subjected to reactive ion etching. At this time, as described above, by the magnetic force from the permanent magnet 32,
Since the electrons between the electrodes move in a cyclone, the plasma of the etching gas is promoted, and a high etching rate of 1 μm / min can be obtained even at a relatively low pressure of 10 ⁻² to 10 ⁻³ Torr.

In this case, the upper member 2 of the support table 20
As described above, since the gas for heat transfer is supplied between the first member and the lower member 22, the heat conduction characteristics between the upper member 21 and the lower member 22 can be improved. Can be made very small. Therefore, by allowing the liquid for temperature control to flow through the liquid passage 23 in the lower member 22, the temperature of the wafer can be reliably controlled. Therefore, the temperature of the wafer can be controlled almost in the same manner as the mounting table having a single structure, even though the support table is a two-split type support table.

Further, the support table 20 is divided into a fixed lower member 22 and a separable upper member 21 so that only the upper member 21 is replaced when the inch size of the wafer 1 is changed. And the replacement of the consumable electrostatic chuck 34 requires only the replacement of the upper member 21 provided with a new electrostatic chuck. it can.

In the above description, an example in which the support table of the object to be processed is applied to the magnetron plasma etching apparatus according to the present invention is shown. However, the present invention is applied to a vacuum processing apparatus from the gist of the present invention. be able to. Examples of such a vacuum processing apparatus include, in addition to the magnetron plasma etching apparatus shown here, other plasma processing apparatuses such as an RIE type plasma etching apparatus, sputtering, CVD, and ion implantation, and a non-source such as an ion source and thermal CVD. There is a plasma processing apparatus. The present invention can be applied to vacuum devices used in various other fields. It goes without saying that the support table may be controlled at a high temperature or at a low temperature. The object to be processed is not limited to a semiconductor wafer, but may be an LCD substrate or the like.

Further, as the gas introduced between the upper member and the lower member, various gases capable of improving heat transfer characteristics can be adopted, and an appropriate gas is used according to the type of the process. be able to.

[0039]

As described above, according to the present invention, the mounting table for holding the electrostatic chuck has a divided structure, so that when the size of the object to be processed is changed or when the consumables are replaced. In such a case, it can be dealt with simply by replacing only one of the mounting tables, and furthermore, between the contact surfaces of both mounting tables ,
Introduce gas between the workpiece and the electrostatic chuck
Rukoto makes it possible to increase the thermal conductivity by the gas in the gap between each, that Do is possible to ensure even the predetermined temperature control operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the configuration of a magnetron plasma etching apparatus using a support table according to one embodiment of the present invention.

FIG. 2 is a sectional view showing details of a support tail used in the apparatus of FIG. 1;

FIG. 3 is a sectional view showing an electrostatic chuck for supporting a wafer used for a support table of the apparatus of FIG. 1;

FIG. 4 is a diagram showing a mechanism for controlling the pressure of a heat transfer gas.

FIG. 5 is a graph for explaining the effect of the heat transfer gas.

[Explanation of symbols]

Reference Signs List 10 vacuum chamber 20 support table 21 upper member 22 lower member 23 liquid passage 25 gas introduction passage 25a ring groove for gas filling
TE0380001

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor, Yukihiro Hasegawa 1 Kosuka Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. Toshiba Research Institute, Inc. No. 1 Toshiba Research Institute, Inc. (56) References JP-A-63-156321 (JP, A) JP-A-1-107541 (JP, A) JP-A-2-120831 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) H01L 21/3065 C23C 14/50 C23C 16/44 C23F 4/00 H01L 21/68

Claims (3)

(57) [Claims] A first mounting table having a temperature control function; a second mounting table provided on the first mounting table; and a second mounting table provided on the second mounting table. An electrostatic chuck for attracting and holding, and a gas inlet for introducing gas between the contact surfaces of the first and second mounting tables .
A gas introduction unit, and a gas introduced between the object to be processed and the electrostatic chuck.
That a second gas introduction section, the processed-body mounting apparatus characterized by having a. 2. The device according to claim 1, wherein the first and second mounting tables are in close contact with each other on a plane.
1. An O-ring is provided between the second mounting table along the outer circumference.
Hermetically sealed, before the hermetically sealed gap area
A mounting device for an object to be processed, wherein a gas is introduced through the first gas introduction unit . 3. A vacuum chamber maintained at a predetermined degree of vacuum, the workpiece mounting device according to claim 1 disposed in the vacuum chamber, A processing device, comprising: processing means for performing processing.