JP2012059858A - Electrostatic chucking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic chucking device in which different electrostatic chucking forces with different magnitude can be applied to each of sections on a substrate, when the substrate is divided into a plurality of sections.SOLUTION: An electrostatic chucking device includes: a stage 11 formed of an dielectric substance and a surface thereof is formed flat; three or more electrostatic chucking electrodes 12 arranged spaced apart from each other within the stage 11; and an electrostatic power source for applying DC voltage to the respective electrostatic electrodes 12. The device is configured in a manner that, when the surface of the stage 11 is divided into a plurality of sections A to D so that one section does not include the other section and each of the sections includes two or more of the electrostatic electrodes 12, voltages of the same magnitudes are applied to the electrostatic electrodes 12 in the same section, and voltages of different magnitudes are respectively applied to the electrostatic electrodes 12 located in two of the sections adjacent to each other. A cross sectional area of each of the electrostatic electrodes 12 parallel to the surface of the stage 11 is 1 cmor less.

Description

  The present invention relates to an electrostatic adsorption device.

Currently, an electrostatic chucking device is used as a device for sucking and holding a substrate as a processing target in a vacuum chamber of a vacuum processing apparatus.
FIG. 7 is an internal configuration diagram of a conventional electrostatic chuck 110, and FIG. 8 is a cross-sectional view taken along the line F-F.

The electrostatic adsorption device 110 includes a stage 111 made of a dielectric whose surface is planar, first and second electrodes 112a and 112b that are spaced apart from each other inside the stage 111, and first and first electrodes. And an electrostatic attraction power source 115 for applying a DC voltage to the second electrodes 112a and 112b.
Here, the first and second electrodes 112a and 112b are formed in the shape of comb teeth, and the tooth portions are oriented in such a manner that they are spaced apart from each other by a certain distance.

  The electrostatic adsorption power source 115 has a positive electrode that outputs a positive voltage and a negative electrode that outputs a negative voltage. The first and second electrodes 112a and 112b are electrically connected to electrodes of different polarities of the electrostatic adsorption power source 115.

  When DC voltages having different polarities are applied from the electrostatic adsorption power source 115 to the first and second electrodes 112a and 112b in a state where an electrically insulating substrate is disposed on the surface of the stage 111, the stage 111 The substrate is electrostatically attracted to the surface of the stage 111 by the dielectric polarization generated inside.

  In the dry etching process using plasma, in the conventional electrostatic adsorption device 110, the processing shape and depth that can be processed into one substrate is one type when the in-plane distribution of the capacitance of the substrate is uniform. It was only.

  For this reason, it is difficult to manufacture so-called mating substrates in which a plurality of types of devices with different etching depths and film thicknesses are formed on a single substrate. This was only possible by creating shapes using different processes, and the process was repeated multiple times, which was inefficient.

  In addition, when etching a substrate with a non-uniform distribution of electrostatic capacity such as a crossing substrate, an in-plane difference occurs in the size of the electrostatic adsorption force received from the electrostatic adsorption device 110. Therefore, it is difficult to perform etching at the same processing rate.

JP 2003-059451 A JP 2006-261489 A

  The present invention was created to solve the above-described disadvantages of the prior art, and the purpose of the present invention is to electrostatically attract each section with a force having a different size for each section when the substrate is divided into a plurality of sections. It is to provide an electrostatic adsorption device.

In order to solve the above-mentioned problems, the present invention provides a stage made of a dielectric having a planar surface, three or more electrostatic chucking electrodes arranged apart from each other in the stage, and each of the static electricity electrodes. An electrostatic attraction power source for applying a DC voltage to the electroadsorption electrode, wherein the section of the stage is not included in another section, and each section is When divided into a plurality of sections so as to include a plurality of the electrostatic adsorption electrodes, the same value of voltage is applied to each of the electrostatic adsorption electrodes located in each section. The electrostatic adsorption device is configured such that different electrostatic voltages are applied to each of the electrostatic adsorption electrodes located in one of the compartments.
The present invention is the electrostatic chucking device in which a cross-sectional area parallel to the surface of the stage of each electrostatic chucking electrode is 1 cm ² or less.

The thermal resistance between the substrate and the stage can be the same value within the compartment and different values between the compartments to which different voltages are applied.
The same shape can be formed in the substrate within the compartment, or a thin film having the same property can be formed, and different shapes can be formed between the compartments to which different voltages are applied, or a thin film having a different property can be formed.

A plurality of types of devices having different etching depths and film thicknesses for each section can be formed on a single substrate.
It is possible to form the same shape in a plane or a thin film having the same property on a substrate having a non-uniform distribution of capacitance.

The internal block diagram of the electrostatic attraction apparatus of this invention Sectional view taken along line E-E of the electrostatic chuck of the present invention The internal block diagram of the plasma etching apparatus which has the electrostatic attraction apparatus of this invention The internal block diagram of the sputtering film-forming apparatus which has the electrostatic attraction apparatus of this invention The internal block diagram of the CVD film-forming apparatus which has the electrostatic attraction apparatus of this invention (A), (b): The figure for demonstrating the example of the shape and arrangement | positioning of an electrostatic adsorption electrode Internal configuration diagram of conventional electrostatic chuck Sectional view taken along line FF of a conventional electrostatic chuck

<Structure of electrostatic chuck>
The structure of the electrostatic attraction apparatus of the present invention will be described.
FIG. 1 is an internal configuration diagram of the electrostatic adsorption device 10, and FIG. 2 is a sectional view taken along line E-E.

  The electrostatic attraction apparatus 10 includes a stage 11 made of a dielectric having a planar surface, three or more electrostatic attraction electrodes 12 disposed inside the stage 11 and spaced apart from each other, and each electrostatic attraction electrode. 12 has an electrostatic attraction power source 15 for applying a DC voltage.

Referring to FIG. 2, here, the cross-sectional shape of each electrostatic chucking electrode 12 parallel to the surface of the stage 11 is a square, and is arranged in a matrix on one plane parallel to the surface of the stage 11.
Referring to FIG. 1, electrostatic attraction power supply 15 includes a ground electrode placed at a ground potential, a positive electrode that outputs a positive potential with respect to the ground potential, and a negative electrode that outputs a negative potential with respect to the ground potential. have.

The electrostatic adsorption device 10 includes a control circuit 14 and a control device 17.
Here, the control circuit 14 has a plurality of transformers 18 and a plurality of polarity switches 19.
Each transformer 18 has an input terminal, an output terminal, and a ground terminal. The ground terminal of each transformer 18 is electrically connected to the ground electrode of the electrostatic attraction power source 15, the output terminal is electrically connected to a different electrostatic attraction electrode 12, and the input terminal is connected to a different polarity switch 19. Electrically connected.

  Each polarity switch 19 is configured to be electrically connected to either the positive electrode or the negative electrode of the electrostatic attraction power supply 15 based on the control signal when receiving the control signal from the control device 17. In other words, the input terminal of the transformer 18 and either the positive electrode or the negative electrode of the electrostatic attraction power supply 15 are electrically connected.

  Each transformer 18 is configured to receive the control signal from the control device 17 and amplify or attenuate the magnitude of the DC voltage applied to the input terminal based on the control signal, and output from the output terminal. Yes.

  The control device 17 is a computer here, and the surface of the stage 11 is positioned inside the other compartment, with one compartment surrounded by an annular compartment, that is, one compartment is included in the other compartment. The electrostatic adsorption located in each of the compartments A to D when divided into a plurality of sections A, B, C, and D so that each section includes a plurality of electrostatic adsorption electrodes 12. Each voltage is applied to the electrode 12 so that the same voltage is applied to each section, and to the electrostatic adsorption electrode 12 positioned in two adjacent sections, different voltages are applied to each section. The voltage change amount of 18 and the electrodes of the electrostatic attraction power source 15 to be connected to each polarity switch 19 are determined.

  Here, the control device 17 is configured so that the relative positional relationship between the substrate disposed on the surface of the stage 11 and each electrostatic adsorption electrode 12 can be known in advance, and a pattern to be formed on the substrate by vacuum processing is determined. When it is predetermined or when a pattern is already formed, the surface of the stage 11 is divided according to the pattern of the substrate.

The cross-sectional area parallel to the surface of the stage 11 of each electrostatic chucking electrode 12 is 1 cm ² or less. Therefore, the position of the boundary line between the sections A to D can be determined in units of 1 cm or less.
The cross-sectional shape of each electrostatic adsorption electrode 12 of the present invention is not limited to a square as shown in FIG. 2, and a circular shape or a polygonal shape is also included in the present invention.

  The arrangement of the electrostatic attraction electrodes 12 of the present invention is not limited to the case where the electrostatic attraction electrodes 12 are arranged apart from each other as shown in FIG. A case in which a staggered arrangement is used as shown in (a) is also included in the present invention.

  Further, as shown in FIG. 6B, the cross-sectional shape of each electrostatic chucking electrode 12 is a band shape, and the longitudinal directions are parallel to each other on one plane parallel to the surface of the stage 11 and are long. Those arranged in a line in a direction perpendicular to the direction are also included in the present invention.

  However, the structure of FIGS. 2 and 6A has a smaller cross-sectional area of each electrostatic adsorption electrode 12 than the structure of FIG. 6B, and the section of the stage 11 is finely divided according to the pattern of the substrate. This is preferable because it can be performed.

<First example of vacuum processing apparatus having electrostatic adsorption apparatus>
A plasma etching apparatus will be described as a first example of a vacuum processing apparatus having the electrostatic adsorption apparatus 10 of the present invention.
FIG. 3 shows an internal configuration diagram of the plasma etching apparatus 20.

The plasma etching apparatus 20 includes a vacuum chamber 21, an evacuation apparatus 22, an electrostatic adsorption apparatus 10 according to the present invention, a substrate cooling apparatus 26, an etching gas introduction unit 23, and plasma generation means.
The stage 11 of the electrostatic adsorption device 10 is disposed in the vacuum chamber 21, and the control circuit 14, the electrostatic adsorption power source 15, and the control device 17 are disposed outside the vacuum chamber 21.

Here, the plasma generation means includes a counter electrode 27 and a plasma generation power source 29.
The counter electrode 27 is disposed at a position facing the surface of the stage 11 while being separated from the surface of the stage 11. The plasma generation power source 29 is electrically connected to the counter electrode 27, and is configured to apply a high frequency voltage to the counter electrode 27 here.

The stage 11 is provided with a through hole penetrating the front surface and the back surface, and the substrate cooling device 26 is connected to the through hole from the back surface side of the stage 11. The substrate cooling device 26 is configured so as to discharge a cooling gas whose temperature is controlled in the through hole.
When the cooling gas is discharged from the substrate cooling device 26 in a state where the substrate 25 is disposed on the surface of the stage 11, the cooling gas flows between the surface of the stage 11 and the back surface of the substrate 25, thereby cooling the substrate 25. It is like that.

When the thermal resistance between the substrate 25 and the stage 11 is uniform, the entire back surface of the substrate 25 is cooled uniformly.
The vacuum evacuation device 22 is connected to the inside of the vacuum chamber 21 so that the inside of the vacuum chamber 21 can be evacuated. The etching gas introduction unit 23 is connected to the inside of the vacuum chamber 21 and is configured so that the etching gas can be introduced into the vacuum chamber 21.
The vacuum chamber 21 is at ground potential.

A method of using the plasma etching apparatus 20 will be described by taking etching of a GaAs substrate as an example.
First, as a comparative example, the inside of the vacuum chamber 21 is evacuated by the evacuation apparatus 22. Thereafter, evacuation is continued, and the vacuum atmosphere in the vacuum chamber 21 is maintained.

  While maintaining the vacuum atmosphere in the vacuum chamber 21, the substrate 25 having electrical insulation is carried into the vacuum chamber 21 and placed on the surface of the stage 11. Here, a GaAs substrate having a diameter of 4 inches is used as the substrate 25. The in-plane distribution of the capacitance of the substrate 25 is made uniform in the plane.

Referring to FIG. 2, the surface of the stage 11 is divided into four sections A, B, C, and D here, and each electrostatic suction located in each section A, B, C, and D from the electrostatic suction power supply 15. A DC voltage of 10 V is applied to all the electrodes 12.
The cooling gas is discharged from the substrate cooling device 26 to cool the substrate 25 on the stage 11 and the cooling is continued thereafter.

An etching gas is introduced into the vacuum chamber 21 from the etching gas introduction unit 23. Here, Cl ₂ gas is used as an etching gas.
When a high frequency voltage is applied from the plasma generation power source 29 to the counter electrode 27, the introduced etching gas is turned into plasma.

  Electrons in the plasma reach the substrate 25, and the substrate 25 is negatively charged and electrostatically attracted to the surface of the stage 11. A positive voltage of the same magnitude is applied to the electrostatic chucking electrode 12, and each portion located in each of the sections A to D of the substrate 25 is chucked on the stage 11 with the same electrostatic chucking force. Is done. Therefore, the thermal resistance between the substrate 25 and the stage 11 is the same between the sections A to D, and the entire substrate 25 is uniformly cooled.

The radicals in the plasma reach the surface of the substrate 25, and the surface of the substrate 25 is etched.
When the voltage supply from the plasma generation power supply 29 is stopped after the etching is continued for a predetermined time, the plasma disappears and the electrostatic adsorption of the substrate 25 is released.

The introduction of the etching gas from the etching gas introduction unit 23 is stopped, and the discharge of the cooling gas from the substrate cooling device 26 is stopped.
The substrate 25 is carried out of the vacuum chamber 21 while maintaining the vacuum atmosphere in the vacuum chamber 21.

  When the processing rate, which is the depth cut per unit time of the substrate 25, is determined for each part corresponding to each of the sections A to D, the processing rate of each part corresponding to each of the sections A to D is 20 Å / min.

  Next, as an example, another substrate 25 is carried in and maintained on the surface of the stage 11 while maintaining the vacuum atmosphere in the vacuum chamber 21. As the substrate 25, a GaAs substrate having a diameter of 4 inches is used. The in-plane distribution of the capacitance of the substrate 25 is made uniform in the plane.

When a DC voltage of 0, 20, -20, or 10 V is applied to the electrostatic chucking electrodes 12 located in the sections A, B, C, and D from the electrostatic chucking power supply 15, respectively, the substrate 25 is moved to the stage 11. It is electrostatically adsorbed on the surface.
The cooling gas is discharged from the substrate cooling device 26 to cool the substrate 25 on the stage 11 and the cooling is continued thereafter.

Since different values of voltage are applied to each section, the magnitude of the electrostatic attraction force is different for each section, and the thermal resistance between the substrate 25 and the stage 11 is different for each section.
In the same manner as in the comparative example, the etching gas is introduced into the vacuum chamber 21 from the etching gas introduction unit 23. An etching gas is Cl ₂ gas.

  When a high frequency voltage is applied from the plasma generation power source 29 to the counter electrode 27, the introduced etching gas is turned into plasma. The radicals in the plasma reach the surface of the substrate 25, and the surface of the substrate 25 is etched.

  After the etching is continued for a predetermined time, the voltage supply from the plasma generation power supply 29 is stopped, and the introduction of the etching gas from the etching gas introduction unit 23 is stopped. Release of the cooling gas from the substrate cooling device 26 is stopped.

  After applying a DC voltage having a reverse polarity to the electrostatic adsorption electrode 12 located in each of the sections A to D to release the electrostatic adsorption of the substrate 25, the vacuum atmosphere in the vacuum chamber 21 is maintained. Then, the substrate 25 is carried out of the vacuum chamber 21.

  When the processing rate, which is the depth cut per unit time of the substrate 25, is obtained for each part corresponding to each of the sections A to D, the processing rate of each part corresponding to each of the sections A, B, C, D is as follows. They were 20, 20, 30, 5 Å / min, respectively.

  Table 1 summarizes the measurement results of the comparative example and the example.

  In other words, it can be understood that etching can be performed at different processing rates for each section by applying a voltage having a different value for each section to each electrostatic chucking electrode 12 to electrostatically attract the substrate 25.

<Second example of vacuum processing apparatus having electrostatic adsorption apparatus>
A sputtering film forming apparatus will be described as a second example of a vacuum processing apparatus having the electrostatic adsorption apparatus 10 of the present invention.

FIG. 4 shows an internal configuration diagram of the sputter deposition apparatus 30.
The sputter deposition apparatus 30 includes a vacuum chamber 31, an evacuation apparatus 32, an electrostatic adsorption apparatus 10 according to the present invention, a substrate cooling apparatus 36, a sputter gas introduction unit 33, a backing plate 37, and a sputter power supply 39. have.
The stage 11 of the electrostatic adsorption device 10 is disposed in the vacuum chamber 31, and the control circuit 14, the electrostatic adsorption power source 15, and the control device 17 are disposed outside the vacuum chamber 31.

The backing plate 37 is disposed at a position facing the surface of the stage 11 while being separated from the surface of the stage 11, and the target 34 is fixed in close contact with the surface of the backing plate 37 facing the surface of the stage 11.
The sputter power source 39 is electrically connected to the backing plate 37, and is configured so that a high frequency voltage can be applied to the backing plate 37 here.

  The stage 11 is provided with a through hole penetrating the front surface and the back surface, and the substrate cooling device 36 is connected to the through hole from the back surface side of the stage 11. The substrate cooling device 36 is configured to be able to release a cooling gas whose temperature is controlled in the through hole.

  When the cooling gas is discharged from the substrate cooling device 36 with the substrate 35 placed on the surface of the stage 11, the cooling gas flows between the surface of the stage 11 and the back surface of the substrate 35, and the substrate 35 is cooled. It has become so.

When the thermal resistance between the substrate 35 and the stage 11 is uniform, the entire back surface of the substrate 35 is uniformly cooled.
The evacuation device 32 is connected to the inside of the vacuum chamber 31 and is configured so that the inside of the vacuum chamber 31 can be evacuated. The sputter gas introduction unit 33 is connected to the inside of the vacuum chamber 31 and is configured so that the sputter gas can be introduced into the vacuum chamber 31.

The vacuum chamber 31 is at ground potential.
A method of using the sputter deposition apparatus 30 will be described by taking sputter deposition of a TiO _x thin film as an example (x is a real number greater than 0 and less than or equal to 2).

First, as a comparative example, the vacuum chamber 31 is evacuated by the vacuum evacuation device 32. Thereafter, evacuation is continued, and the vacuum atmosphere in the vacuum chamber 31 is maintained.
A TiO _x target 34 is fixed to the surface of the backing plate 37 in advance.

  While maintaining the vacuum atmosphere in the vacuum chamber 31, the substrate 35 having electrical insulation is carried into the vacuum chamber 31 and placed on the surface of the stage 11. The in-plane distribution of the capacitance of the substrate 35 is made uniform in the plane.

Referring to FIG. 2, the surface of the stage 11 is divided into four sections A, B, C, and D here, and each electrostatic suction located in each section A, B, C, and D from the electrostatic suction power supply 15. A DC voltage of 10 V is applied to all the electrodes 12.
With reference to FIG. 4, the cooling gas is discharged from the substrate cooling device 36 to cool the substrate 35 on the stage 11, and the cooling is continued thereafter.

A sputtering gas is introduced into the vacuum chamber 31 from the sputtering gas introduction part 33. Here, Ar gas is used as the sputtering gas.
When a high frequency voltage is applied from the sputtering power source 39 to the backing plate 37, the introduced sputtering gas is turned into plasma.

  Electrons in the plasma reach the substrate 35, the substrate 35 is negatively charged, and is electrostatically attracted to the surface of the stage 11. A positive voltage of the same magnitude is applied to the electrostatic chucking electrode 12, and each part located in each of the sections A to D of the substrate 35 is chucked to the stage 11 with the same electrostatic chucking force. Is done. Therefore, the thermal resistance between the substrate 35 and the stage 11 is the same between the sections A to D, and the entire substrate 35 is uniformly cooled.

Ions in the plasma are incident on the surface of the target 34 and sputter the target 34. The TiO _x particles released from the target 34 reach the surface of the substrate 35, and a TiO _x thin film is formed on the surface of the substrate 35.
When the supply of voltage from the sputtering power source 39 is stopped after the sputtering is continued for a predetermined time, the plasma disappears and the electrostatic adsorption of the substrate 35 is released.

The introduction of the sputtering gas from the sputtering gas introduction unit 33 is stopped, and the discharge of the cooling gas from the substrate cooling device 36 is stopped.
The substrate 35 is carried out of the vacuum chamber 31 while maintaining the vacuum atmosphere in the vacuum chamber 31.

When the volume resistivity of the TiO _x thin film formed on the substrate 35 is determined in each part corresponding to each of the sections A to D, the volume resistivity of each part corresponding to each of the sections A to D is 10 ¹⁴ Ω. / Cm ³ .

Next, as an example, another substrate 35 is carried in and maintained on the surface of the stage 11 while maintaining the vacuum atmosphere in the vacuum chamber 31. The in-plane distribution of the capacitance of the substrate 35 is made uniform in the plane.
When a DC voltage of 0, 20, -20, or 10 V is applied to the electrostatic chucking electrodes 12 in the sections A, B, C, and D from the electrostatic chucking power source 15, the substrate 35 becomes the surface of the stage 11. Is electrostatically adsorbed on the surface.

Cooling gas is discharged from the substrate cooling device 36 to cool the substrate 35 on the stage 11, and then cooling is continued.
Since different values of voltage are applied to each section, the magnitude of the electrostatic attraction force is different for each section, and the thermal resistance between the substrate 35 and the stage 11 is different for each section.
As in the comparative example, the sputtering gas is introduced into the vacuum chamber 31 from the sputtering gas introduction unit 33.

When a high frequency voltage is applied from the sputtering power source 39 to the backing plate 37, the introduced sputtering gas is turned into plasma. Ions in the plasma are incident on the surface of the target 34 and sputter the surface of the target 34. The TiO _x particles released from the target 34 reach the surface of the substrate 35, and a TiO _x thin film is formed on the surface of the substrate 35.

  After the sputtering is continued for a predetermined time, the voltage supply from the sputtering power source 39 is stopped, and the introduction of the sputtering gas from the sputtering gas introduction unit 33 is stopped. Release of the cooling gas from the substrate cooling device 36 is stopped.

  After applying a DC voltage having a reverse polarity to the electrostatic adsorption electrodes 12 located in the sections A to D to release the electrostatic adsorption of the substrate 35, the vacuum atmosphere in the vacuum chamber 31 is maintained. Then, the substrate 35 is carried out of the vacuum chamber 31.

When the volume resistivity of the thin film of TiO _x formed on the substrate 35 is determined in each part corresponding to each of the sections A to D, the volume resistivity of each part corresponding to each of the sections A, B, C, D is respectively 10 ¹³ , 10 ¹² , 10 ¹² , 10 ¹⁴ Ω / cm ³ .

  Table 2 summarizes the measurement results of the comparative example and the example.

That is, it can be seen that a TiO _x thin film having a different volume resistivity can be formed for each section by applying a voltage having a different value to each electrostatic adsorption electrode 12 to adsorb the substrate 35.

<Third embodiment of electrostatic adsorption device>
A plasma CVD film forming apparatus will be described as a third example of a vacuum processing apparatus having the electrostatic adsorption apparatus 10 of the present invention.
FIG. 5 shows an internal configuration diagram of the CVD film forming apparatus 40.

The CVD film formation apparatus 40 includes a vacuum chamber 41, an evacuation apparatus 42, an electrostatic adsorption apparatus 10 of the present invention, a substrate heating apparatus, a shower plate 47, a source gas source 44, a reaction gas source 43, And a plasma generation power source 49.
The stage 11 of the electrostatic adsorption device 10 is disposed in the vacuum chamber 41, and the control circuit 14, the electrostatic adsorption power source 15, and the control device 17 are disposed outside the vacuum chamber 41.

The shower plate 47 is a hollow casing, and a plurality of discharge holes are provided on one surface.
The shower plate 47 is disposed at a position facing the surface of the stage 11 so as to be separated from the surface of the stage 11, and the surface provided with the discharge hole is directed to face the surface of the stage 11.

The source gas source 44 and the reaction gas source 43 are configured to release a source gas and a reaction gas that reacts when mixed with the source gas.
The source gas source 44 and the reaction gas source 43 are respectively connected to the shower plate 47, and the source gas released from the source gas source 44 and the reaction gas released from the reaction gas source 43 reach the discharge holes of the shower plate 47. Until they are mixed with each other, they are mixed after being discharged into the vacuum chamber 41 from the discharge hole.

A plasma generation power source 49 is electrically connected to the shower plate 47 so that a high frequency voltage can be applied to the shower plate 47.
Here, the substrate heating apparatus has a hot plate 48 in which an electrothermal resistance is embedded, and a heating power source 50. The hot plate 48 is disposed on the back surface of the stage 11, and the heating power supply 50 is electrically connected to an electric heating resistor inside the hot plate 48.

When a direct current is passed from the heating power supply 50 to the electrothermal resistor, the electrothermal resistor generates heat and heats the stage 11 and the substrate 45 disposed on the stage 11.
When the thermal resistance between the substrate 45 and the stage 11 is uniform, the entire back surface of the substrate 45 is heated uniformly.
The vacuum exhaust device 42 is connected to the inside of the vacuum chamber 41 so that the inside of the vacuum chamber 41 can be evacuated.
The vacuum chamber 41 is at ground potential.

A method of using the CVD film forming apparatus 40 will be described by taking the CVD film formation of a SiN thin film as an example.
First, as a comparative example, the vacuum chamber 41 is evacuated by the vacuum evacuation device 42. Thereafter, evacuation is continued, and the vacuum atmosphere in the vacuum chamber 41 is maintained.

  While maintaining the vacuum atmosphere in the vacuum chamber 41, the substrate 45 having electrical insulation is carried into the vacuum chamber 41 and placed on the surface of the stage 11. The in-plane distribution of the capacitance of the substrate 45 is made uniform in the plane.

Referring to FIG. 2, the surface of the stage 11 is divided into four sections A, B, C, and D here, and each electrostatic suction located in each section A, B, C, and D from the electrostatic suction power supply 15. A DC voltage of 10 V is applied to all the electrodes 12.
Referring to FIG. 5, a direct current is passed from the heating power source 50 to the electric heating resistor inside the hot plate 48 to heat the substrate 45 on the stage 11, and then the heating is continued.

Here, SiH ₄ gas is used as the source gas, and NH ₃ gas is used as the reaction gas.
When the source gas and the reaction gas are respectively released from the source gas source 44 and the reaction gas source 43, the source gas and the reaction gas are released from the discharge holes of the shower plate 47 into the vacuum chamber 41 and mixed.

When a high frequency voltage is applied from the plasma generation power source 49 to the shower plate 47, the released source gas and reaction gas are turned into plasma.
Electrons in the plasma reach the substrate 45, and the substrate 45 is negatively charged and electrostatically attracted to the surface of the stage 11. A positive voltage of the same magnitude is applied to the electrostatic chucking electrode 12, and each portion located in each of the sections A to D of the substrate 45 is chucked on the stage 11 with the same electrostatic chucking force. Is done. Therefore, the thermal resistance between the substrate 45 and the stage 11 is the same between the sections A to D, and the entire substrate 45 is heated uniformly.

The radicals in the plasma cause a chemical reaction on the heated substrate 45, and a SiN thin film is formed on the surface of the substrate 45.
After the CVD film formation is continued for a predetermined time, when the voltage supply from the plasma generation power supply 49 is stopped, the plasma disappears and the electrostatic adsorption of the substrate 45 is released.

Release of the source gas and the reaction gas from the source gas source 44 and the reaction gas source 43 is stopped, and the current supply from the heating power source 50 is stopped.
The substrate 45 is carried out of the vacuum chamber 41 while maintaining the vacuum atmosphere in the vacuum chamber 41.

  When the refractive index of the SiN thin film formed on the substrate 45 was determined in each part corresponding to each of the sections A to D, the refractive index of each part corresponding to each of the sections A to D was 1.9. .

Next, as an example, another substrate 45 is carried in and maintained on the surface of the stage 11 while maintaining the vacuum atmosphere in the vacuum chamber 41. The in-plane distribution of the capacitance of the substrate 45 is made uniform in the plane.
When a DC voltage of 0, 20, -20, or 10 V is applied to the electrostatic chucking electrodes 12 located in the sections A, B, C, and D from the electrostatic chucking power source 15, respectively, the substrate 45 is moved to the stage 11. It is electrostatically adsorbed on the surface.

A direct current is supplied from the heating power source 50 to the electric heating resistor inside the hot plate 48 to heat the substrate 45 on the stage 11 and the heating is continued thereafter.
Since different values of voltage are applied to each section, the magnitude of the electrostatic adsorption force for each section is different, and the thermal resistance between the substrate 45 and the stage 11 is different for each section.

  Similarly to the comparative example, when the source gas and the reaction gas are respectively released from the source gas source 44 and the reaction gas source 43, the source gas and the reaction gas are released into the vacuum chamber 41 from the discharge hole of the shower plate 47 and mixed. Fit.

  When a high frequency voltage is applied from the plasma generation power source 49 to the shower plate 47, the released source gas and reaction gas are turned into plasma. The radicals in the plasma cause a chemical reaction on the heated substrate 45, and a SiN thin film is formed on the surface of the substrate 45.

  After the CVD film formation is continued for a predetermined time, the voltage supply from the plasma generation power source 49 is stopped, and the release of the source gas and the reaction gas from the source gas source 44 and the reaction gas source 43 is stopped. The current supply from the heating power supply 50 is stopped.

  After applying a DC voltage having the opposite polarity to the electrostatic adsorption electrode 12 located in each of the sections A to D to release the electrostatic adsorption of the substrate 45, the vacuum atmosphere in the vacuum chamber 41 is maintained. Then, the substrate 45 is carried out of the vacuum chamber 41.

  When the refractive index of the SiN thin film formed on the substrate 45 is determined in each part corresponding to each of the sections A to D, the refractive index of each part corresponding to each of the sections A, B, C, D is 1.8. 1.9, 2.1, and 1.9.

  Table 3 summarizes the measurement results of the comparative example and the example.

  That is, it can be seen that SiN thin films having different refractive indexes can be formed for each section by applying a voltage having a different value to each electrostatic adsorption electrode 12 to adsorb the substrate 45.

  In the embodiment described above, a voltage having a different value for each section is applied to the electrostatic adsorption electrode located in each section with respect to the substrate having a uniform in-plane electrostatic capacitance distribution. Although different portions located in each other are electrostatically adsorbed by forces of different magnitudes to form different shapes or thin films having different properties, the present invention has an in-plane distribution of capacitance. When the in-plane distribution is known for a non-uniform substrate, sections are divided according to the in-plane distribution, and different values of voltage are applied to the electrostatic adsorption electrodes located in each section. The surface of the substrate can be electrostatically adsorbed with the same magnitude of force to form the same shape within the surface, or a thin film having the same properties can be formed within the surface.

  The plasma generating means of the vacuum processing apparatuses 20, 30, and 40 having the electrostatic attraction apparatus 10 of the present invention is not limited to the above configuration as long as the gas introduced into the vacuum chamber can be converted into plasma. It can also be constituted by other known techniques such as a mold, an ECR type, a helicon type, and an ICP type.

  As described above, the electrostatic adsorption apparatus 10 of the present invention is not limited to the one used in the plasma etching apparatus 20, the sputter film forming apparatus 30, and the CVD film forming apparatus 40. It can also be used in other vacuum processing equipment that uses plasma for processing.

  Further, the electrostatic adsorption device 10 of the present invention is a bipolar type in which a positive voltage is applied to an electrostatic adsorption electrode located in at least one section and a negative voltage is applied to an electrostatic adsorption electrode located in another section. When used as an electrostatic attraction apparatus, a vacuum processing apparatus that does not use plasma for processing a substrate, such as a vacuum deposition apparatus, can also be used.

The substrate to be adsorbed by the electrostatic adsorption device 10 of the present invention and the thin film formed on the substrate are not limited to the above materials as long as they have electrical insulation properties, and Al ₂ O ₃ , SiO ₂ , PZT, LiNbO. _3. Materials such as SiC can also be used.

10 …… Electrostatic adsorption device 11 …… Stage 12 …… Electrostatic adsorption electrode 15 …… Electrostatic adsorption power source

Claims (2)

A stage made of a dielectric with a planar surface;
Three or more electrostatic chucking electrodes disposed apart from each other inside the stage; and
An electrostatic adsorption power source for applying a DC voltage to each of the electrostatic adsorption electrodes;
An electrostatic adsorption device having
When the surface of the stage is divided into a plurality of sections so that one section is not included in another section and each section includes a plurality of electrostatic adsorption electrodes, respectively.
A voltage having the same value is applied to each electrostatic adsorption electrode located in each compartment for each compartment,
An electrostatic adsorption device configured such that different electrostatic voltages are applied to each of the electrostatic adsorption electrodes positioned in two adjacent compartments. The electrostatic attraction apparatus according to claim 1, wherein a cross-sectional area of each electrostatic attraction electrode parallel to the surface of the stage is 1 cm ² or less.

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