TW201407714A - Plasma processing apparatus - Google Patents

Abstract

A plasma processing apparatus comprises a reaction chamber, an excitation radio-frequency power source, a direct-current power source, an upper electrode, and a chip support device disposed in the reaction chamber and at a position relative to the upper electrode, the upper electrode being connected to the excitation radio-frequency power source to generate plasma in the reaction chamber. The chip support device comprises a tray for carrying a chip and a chuck, a tray electrode is provided in the tray, the tray is placed on the chuck and is electrically insulated from the chuck, the tray and the chuck are both electrically insulated from the plasma, the tray electrode is electrically connected to a positive output terminal or a negative output terminal of the direct-current power source, a chuck electrode is provided in the chuck, and the chuck electrode is grounded, so that a voltage difference exists between the tray and the chuck and exists between the tray and the chip. The plasma processing apparatus is advantageous in being easy to operate, having high reliability, a simple structure and a low cost, and being not easily damaged.

Description

Plasma processing equipment

The invention belongs to the field of semiconductor processing, and in particular relates to a plasma processing apparatus.

Plasma processing equipment is a common device for processing semiconductor devices. Moreover, in order to improve the processing efficiency of the plasma processing apparatus, a plurality of wafers having a small size are often placed on the surface of the larger-sized tray, and then the tray is placed on the upper surface of the chuck of the plasma processing chamber to face the wafer. Processing.

In actual processing, the plasma tends to cause the temperature of the wafer to exceed the temperature required for the process, so the temperature of the wafer needs to be controlled. The conventional temperature control method is to blow a refrigerant gas such as helium gas to the back surface of the wafer (that is, the side opposite to the surface to be processed of the wafer), and adjust the temperature of the wafer by the refrigerant gas. Generally, in order to fix the wafer on the tray and prevent leakage of the refrigerant gas, a pressing unit is generally provided in the edge region of the surface to be processed of the wafer to apply a force toward the chuck region to the edge region of the wafer. However, in practical applications, this method has problems such as troublesome implementation, poor stability, and unsatisfactory cooling effect; in addition, the pressing unit needs to occupy a part of the space on the processed surface of the wafer, which will reduce the effective processing area of the wafer.

To this end, the relevant technicians have developed the use of electrostatic adsorption. The method of fixing the wafer. 1 is a schematic cross-sectional view showing a part of a structure of a plasma processing apparatus for fixing a wafer by electrostatic adsorption. As shown in FIG. 1, the tray 102 is placed on the upper surface of the tray support table 101, and the wafer S is placed on the upper surface of the tray 102. The electrostatic adsorption electrode 106 is provided in the tray 102, and the electrostatic adsorption electrode 106 is electrically connected to the ESC (ElectroStatic Chuck) power supply source 105 via a spring type terminal. In the plasma environment, the electrostatic adsorption electrode 106 is supplied with power, and a conductive layer is formed on the upper surface of the wafer S such that a voltage difference exists between the wafer S and the electrostatic adsorption electrode 106, thereby fixing the wafer S to the upper surface of the tray 102. . An area on the upper surface of the tray 102 that is not covered by the wafer S is covered with a cover plate 103. A mechanical pressure ring 104 is provided on the upper surface of the cover plate 103, and the tray 102 is fixed to the upper surface of the tray support table 101 by means of the mechanical pressure ring 104.

Although the plasma processing apparatus uses the electrostatic adsorption method to fix the wafer S on the surface of the tray 102, the fixing of the tray 102 still requires the use of the mechanical pressure ring 104. Therefore, the wafer fixing method used in the plasma processing apparatus shown in FIG. Inevitably, there are problems in that the structure is complicated, the manufacturing cost is high, the operation is troublesome, the mechanical parts are easily damaged, and the processing efficiency of the plasma processing equipment is affected by the maintenance work, and the like.

In order to at least solve one of the above problems, the present invention provides a plasma processing apparatus which has a simple structure, a low cost, and is not easily damaged.

The technical solution adopted to solve the above technical problems is to provide a plasma processing apparatus, including a reaction chamber, an excitation RF power source, a DC power source, an upper electrode, and a wafer supporting device disposed opposite to the upper electrode in the reaction chamber, the upper electrode being coupled to the excitation RF power source to generate a plasma in the reaction chamber, the wafer support The apparatus includes a tray carrying a wafer and a chuck, wherein a tray electrode is disposed in the tray, the tray is placed on the chuck and electrically insulated therebetween, and the tray and the chuck are both plasma-assisted Electrically insulated, the tray electrode is electrically connected to a positive output terminal or a negative output terminal of the DC power source, a chuck electrode is disposed in the chuck, and the chuck electrode is grounded to make the tray and the There is a voltage difference between the chucks and between the tray and the wafer.

The DC power source includes a positive output terminal, a negative output terminal, and a common terminal, and the common terminal is grounded; or the DC power supply includes a positive output terminal and a common terminal, and the common terminal is grounded; or the DC power supply A negative output terminal and a common terminal are included, and the common terminal is grounded.

The DC power supply includes a positive output terminal and a negative output terminal, the tray electrode is electrically connected to a positive output terminal of the DC power source, and the negative output terminal is grounded; or the tray electrode and the DC power source are The negative output terminal is electrically connected, and the positive output terminal is grounded.

Wherein, a filter circuit is connected in series between the tray electrode and the DC power source; and/or a filter circuit is connected in series between the chuck electrode and the ground.

Wherein, the filter circuit is a high frequency high voltage resistor.

The filter circuit is a filter circuit with a radio frequency attenuation of less than -10 dB.

Wherein, comprising n inductors and n capacitors, the n inductors are connected in series, the n capacitors are connected in parallel, the n inductors are connected in series and then connected in parallel with the n capacitors, and the n capacitors are connected in parallel One end is grounded, n An integer of 1.

Wherein the tray is made of a conductive material, and the surface of the conductive material is coated with an insulating material as the tray electrode; the chuck is made of a conductive material and is on the surface of the conductive material An insulating material is coated, the conductive material serving as the chuck electrode.

Wherein the insulating material forms an insulating layer on a surface of the conductive material.

Wherein, the insulating layer is formed on the surface of the conductive material by spraying or anodizing.

Wherein the tray is made of an insulating material, and a tray electrode is embedded inside the insulating material, the tray electrode is made of a conductive material; the chuck is made of an insulating material, and a chuck electrode is embedded inside the insulating material. The chuck electrode is made of a conductive material.

Wherein, a first chuck refrigerant passage for cooling the chuck is disposed in the chuck, and the chuck is cooled by passing a first cold medium in the first chuck refrigerant passage.

The second chuck refrigerant passage extending through the thickness direction thereof is further disposed in the chuck, and a chuck annular groove is disposed on the upper surface of the chuck, the chuck annular groove and the first The two chucks are connected to the refrigerant passage; the tray is provided with a tray refrigerant passage extending through the thickness direction thereof, the tray refrigerant passage is in communication with the chuck annular groove, and the second cold medium is sequentially passed through the second chuck refrigerant passage The chuck annular groove and the tray refrigerant channel are supplied to the back side of the wafer to cool the wafer.

Wherein, the ion processing apparatus further includes a cover plate, the cover plate is disposed on the bearing surface of the tray, and a positioning hole penetrating the thickness thereof is disposed in the cover plate, and the cover plate is used for protecting the tray bearing surface The area on which the wafer is not placed is protected from plasma bombardment; a boss is provided on the carrying surface of the tray and opposite to the positioning hole, and the wafer is disposed at the top end of the boss.

Wherein, the plasma processing equipment is an LED etching machine or an ITO physical vapor deposition equipment.

Wherein, the material of the wafer is sapphire, ruthenium or ruthenium oxide.

The present invention has the following beneficial effects: the plasma processing apparatus provided by the present invention places a tray on the upper surface of the chuck, electrically insulated between the tray and the chuck, and the tray and the chuck are electrically insulated from the plasma, A tray electrode is disposed in the tray, and the chuck electrode is provided in the chuck, the tray electrode is electrically connected to the positive output terminal or the negative output terminal of the DC power source, and the chuck electrode is grounded to cause a voltage difference between the tray and the chuck , that is, an electrostatic attraction force is generated between the tray and the chuck to fix the tray to the upper surface of the chuck; and a voltage difference exists between the tray and the wafer, that is, electrostatic attraction is generated between the tray and the wafer, Thereby, the wafer is fixed on the upper surface of the tray, and the method of fixing the wafer and the tray is not only easy to operate, but also has high reliability, and has the advantages of simple structure, low cost, and not easy to be damaged.

10‧‧‧ Plasma

12‧‧‧First matcher

13‧‧‧Incentive RF power supply

17‧‧‧Second matcher

18‧‧‧Bias RF power supply

20‧‧‧Reaction chamber

21‧‧‧Tray

21a‧‧‧Tray refrigerant channel

21c‧‧‧ boss

23‧‧‧ chuck

23a‧‧‧First Chuck Refrigerant Channel

23b‧‧‧Second chuck refrigerant channel

24‧‧‧DC power supply

25‧‧‧ Cover

25a‧‧‧Positioning holes

27‧‧‧Media window

30, 30', 30" ‧ ‧ filter circuit

101‧‧‧Tray support table

102‧‧‧Tray

103‧‧‧ Cover

104‧‧‧Mechanical pressure ring

105‧‧‧ESC power supply

106‧‧‧Electrostatic adsorption electrode

A‧‧‧ chuck ring groove

B‧‧‧Tray ring groove

S‧‧‧ wafer

L21‧‧‧First filter inductor

C21‧‧‧First filter capacitor

L22‧‧‧Second filter inductor

C22‧‧‧Second filter capacitor

1 is a schematic cross-sectional view showing a part of a structure of a plasma processing apparatus for fixing a wafer by electrostatic adsorption; 2 is a schematic cross-sectional view showing a part of a structure of a plasma processing apparatus according to an embodiment of the present invention; FIG. 3 is a schematic diagram of another filter circuit according to an embodiment of the present invention; A schematic cross-sectional view of a portion of the structure of the processing equipment.

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the plasma processing apparatus provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Please refer to FIG. 2 , which is a cross-sectional view showing a partial structure of a plasma processing apparatus according to an embodiment of the present invention. As shown in FIG. 2, the plasma processing apparatus includes a reaction chamber 20 to which the reaction chamber 20 is grounded. A chuck 23 is provided at the bottom in the reaction chamber 20, and a tray 21 for carrying the wafer S is placed on the upper surface of the chuck 23. A DC power source 24 and an excitation RF power source are provided outside the reaction chamber 20, wherein the RF power source is energized for exciting the plasma 10, and the DC power source 24 is used to supply energy for fixing the wafer S and the tray 21.

In the present embodiment, the chuck 23 is mainly made of a conductive material such as metal, and an insulating layer is formed on the surface of the conductive material. The conductive material is used as a chuck electrode (or a chuck electrostatic adsorption electrode). The insulating layer is made of an insulating material, and the insulating layer can be formed on the surface of the conductive material by spraying or anodizing. The purpose of providing an insulating material on the surface of the electrically conductive material is to achieve electrical insulation between the chuck 23 and the tray 21 and to electrically insulate the chuck 23 from the plasma 10 within the reaction chamber 20.

The tray 21 is mainly made of a conductive material such as metal, and The surface of the conductive material is formed with an insulating layer. The insulating layer is made of an insulating material, and the insulating layer can be formed on the surface of the conductive material by spraying or anodizing. The conductive material is used as a tray electrode (or a tray electrostatic adsorption electrode). Similar to the chuck 23, the purpose of providing an insulating material on the surface of the conductive material is to achieve electrical insulation between the tray 21 and the chuck 23, and to electrically insulate the tray 21 from the plasma 10 in the reaction chamber 20.

In another embodiment, the chuck 23 may be mainly made of an insulating material, and a chuck electrode made of a conductive material such as metal may be embedded in the insulating material. Similarly, the tray 21 may be mainly made of an insulating material, and a tray electrode made of a conductive material such as metal may be embedded in the insulating material.

The conductive material used for the chuck electrostatic adsorption electrode and the tray electrostatic adsorption electrode in the above embodiment may be a metal material such as aluminum, and the insulating material may be quartz or ceramic.

In the present embodiment, the DC power source 24 includes a positive terminal, a negative terminal, and a common terminal (or referred to as an intermediate point CT), and the common terminal is directly grounded, or the common terminal is grounded via the casing. The tray electrode is electrically connected to the negative terminal of the DC power source 24; the chuck electrode is electrically connected to the common terminal of the DC power source 24, or directly grounded. Of course, the tray electrode can also be electrically connected to the positive terminal of the DC power source 24; the chuck is electrically connected to the common terminal of the DC power source 24, or directly grounded.

In the plasma environment, the surface of the wafer S forms a conductive layer, and the DC power source 24 supplies electric power to the tray electrodes to cause a voltage difference between the tray 21 and the wafer S, and electrostatic attraction between the tray 21 and the wafer S. To fix the wafer S to the upper surface of the tray 21. At the same time, make There is a voltage difference between the tray 21 and the chuck 23, and an electrostatic attraction force is generated between the tray 21 and the chuck 23 to fix the tray 21 to the upper surface of the chuck 23.

In this embodiment, a filter circuit 30 can be connected in series between the DC power source 24 and the tray electrode to avoid RF energy attenuation caused by leakage of RF energy through the loop, and to avoid radio frequency interference to other devices. The filter circuit 30 has a first terminal and a second terminal, wherein the first terminal of the filter circuit 30 refers to the end of the filter circuit 30 connected to the tray electrode; the second terminal of the filter circuit 30 It refers to the end of the filter circuit 30 that is connected to the DC power source 24. As shown in FIG. 2, the filter circuit 30 includes a first filter inductor L21 and a first filter capacitor C21. One end of the first filter inductor L21 is connected to the tray electrode as a first terminal of the filter circuit 30, and the other end serves as a filter circuit 30. The second terminal is connected to the negative terminal of the DC power source 24. One end of the first filter capacitor C21 is grounded, and the other end is connected to the second terminal of the filter circuit and the cathode of the DC power source 24.

Similarly, in the embodiment, a filter circuit 30' may be connected in series between the chuck electrode and the ground (or the common end of the DC power source 24), and the filter circuit 30' has a first terminal and a second terminal. Wherein, the first terminal of the filter circuit 30' refers to the end of the filter circuit 30' connected to the chuck electrode; the second terminal of the filter circuit 30' refers to the filter circuit 30' and the ground ( Or the end of the DC power supply 24). As shown in FIG. 2, the filter circuit 30' includes a second filter inductor L22 and a second filter capacitor C22, and a second filter inductor L22 and a second filter capacitor C22 are coupled to the chuck electrode and the ground (or the common terminal of the DC power source 24). )Connection The manner is similar to the manner in which the first filter inductor L21 and the first filter capacitor C21 are connected to the negative electrode of the tray electrode and the DC power source 24, and details are not described herein again.

In another embodiment, the filter circuit 30" shown in FIG. 3 may be used instead of the filter circuit 30 of FIG. 2. The filter circuit 30" also has a first terminal and a second terminal, wherein the filter circuit The first terminal of 30" refers to the end of the filter circuit 30" that is connected to the tray electrode; the second terminal of the filter circuit 30" refers to the end of the filter circuit 30" that is connected to the DC power supply 24 . As shown in FIG. 3, the filter circuit 30" in this embodiment includes a first filter inductor L21, a second filter inductor L22, a first filter capacitor C21, and a second filter capacitor C22, wherein the first filter inductor L21 and the second The filter inductors L22 are connected in series, and the ends of the first filter inductor L21 and the second filter inductor L22 that are not connected to each other are respectively used as the first terminal and the second terminal of the filter circuit 30", and respectively connect the tray electrode and the DC power source. The negative pole of 24. The first filter capacitor C21 and the second filter capacitor C22 are connected in parallel. One end of the first filter capacitor C21 and the second filter capacitor C22 are grounded, and the other end is connected to the second terminal of the filter circuit 30". Actually, as long as the filter circuit includes n Inductance and n capacitors, n is An integer of 1 and, in addition, n inductors are connected in series, n capacitors are connected in parallel, and n inductors are connected in series and then connected in parallel with n capacitors, and one end of the parallel connection of n capacitors is grounded. The filter circuit of this structure can be used to prevent Radio frequency energy is leaked. In other words, in practical applications, a filter circuit may be employed instead of the filter circuit 30 of FIG. 2, that is, the filter circuit includes n inductors and n capacitors, and n inductors are connected in series, n capacitors are connected in parallel, and n The inductors are connected in series and then connected in parallel with n capacitors. One end of the n capacitors connected in parallel is grounded, where n is an integer greater than or equal to 1.

In practical applications, the filter circuit used in the above embodiments needs to meet the condition that the radio frequency attenuation is less than -10 dB. Also, although only two types of filter circuits are listed above: the combination of the filter circuit 30 and the filter circuit 30' and the filter circuit 30", the filter circuit that can be employed in the present invention is not limited to the above two forms, but It can be constructed in any combination of inductance, resistance and capacitance. Of course, the filter circuit can also use high-frequency high-voltage resistors. In fact, any filter circuit capable of avoiding leakage of RF energy through the loop can be applied to the present invention.

During the plasma processing process, the temperatures of the wafer S, the tray 21, and the chuck 23 are easily increased to affect the quality of the film, and therefore, it is necessary to adjust the temperatures of the wafer S, the tray 21, and the chuck 23 by using a cold medium. Among them, the cold medium can be either a refrigerant liquid or a refrigerant gas.

In the present embodiment, a first chuck refrigerant passage 23a for cooling the chuck 23 is provided in the chuck 23. The first chuck refrigerant passage 23a may be disposed in the form of a plurality of blind holes extending in the thickness direction of the chuck 23, and the opening of the blind hole is disposed on the bottom surface of the chuck 23; or, the first chuck refrigerant The passage 23a can also be provided in the form of a communicating annular groove or a spiral groove. During the process, the first cold medium may be introduced into the first chuck refrigerant passage 23a to cool the chuck 23. The first cold medium may be a refrigerant liquid, and specifically, the refrigerant liquid may be a fluorine coolant.

In another embodiment, a plurality of chuck through holes that penetrate the chuck 23 in the thickness direction and serve as the second chuck refrigerant passage 23b are provided in the chuck 23. Moreover, a plurality of trays are penetrated in the thickness direction in the tray 21 21 and used as a tray through hole of the tray refrigerant passage 21a, on the upper surface of the chuck 23 (i.e., the bearing surface for carrying the tray 21), a chuck annular groove A, a second chuck refrigerant passage 23b and a tray are formed. The refrigerant passages 21a extend to the chuck annular groove A in the thickness direction of the chuck 23 and the thickness direction of the tray 21, respectively, that is, the chuck annular groove A connects the second chuck refrigerant passage 23b and the tray refrigerant passage 21a. . Thus, in the actual process, the second cold medium is sequentially supplied to the back surface of the wafer S via the second chuck refrigerant passage 23b, the chuck annular groove A, and the tray refrigerant passage 21a, thereby cooling the wafer S. The second cold medium is a refrigerant gas, and the refrigerant gas may be an inert gas such as helium.

Preferably, a tray annular groove B is formed on the lower surface of the tray 21, the tray annular groove B is opposite to the chuck annular groove A, and the second chuck can be ensured by the chuck annular groove A and the tray annular groove B The refrigerant passage 23b communicates with the tray refrigerant passage 21a, and allows the second refrigerant medium to enter the tray refrigerant passage 21a more smoothly.

Preferably, a plurality of second chuck refrigerant passages 23b communicating with the annular groove A of the chuck are provided in the chuck 23, and a plurality of tray refrigerant passages 21a are provided in the tray 21, so that a plurality of second cards are provided The disk refrigerant passage 23b and the tray refrigerant passage 21a can not only adjust the temperature more efficiently, but also improve the uniformity of the temperature of each of the chuck 23, the tray 21, and the wafer S.

The surface portion of the tray 21 exposed in the plasma 10 (i.e., the portion of the tray 21 not covered by the wafer S) is susceptible to corrosion by the plasma 10 during wafer processing. To this end, the plasma processing apparatus provided in this embodiment further includes a cover plate 25 made of ceramic or quartz material, which is stacked on the bearing surface of the tray 21 and passed through the screw (Fig. Not shown) is fixed to the tray 21, and the screw is made of a ceramic material. A positioning hole 25a penetrating the thickness thereof is provided in the cap plate 25, and the wafer S is embedded in the positioning hole 25a. It should be noted that, since the cover plate 25 is overlapped with the tray 21, the position of the positioning hole 25a is the position of the wafer S on the surface of the tray 21. Therefore, the positioning hole 25a disposed on the cover plate 25 is advantageous for improving the loading efficiency of the wafer S. . It is not difficult to understand that the inner diameter of the positioning hole 25a should be equal to or slightly larger than the outer diameter of the wafer S. Preferably, the outer diameter of the cover plate 25 is equal to or slightly larger than the outer diameter of the tray 21, so that at least a portion of the bearing surface of the tray 21 exposed in the plasma 10 environment can be blocked, thereby avoiding the plasma 10. The tray 21 is etched.

In the present embodiment, a boss 21c is provided on the carrying surface of the tray 21, the boss 21c is opposed to the positioning hole 25a, and the wafer S is placed on the top end of the boss 21c. In order to enable the tray 21 to carry a plurality of wafers S, a plurality of bosses 21c are provided on the bearing surface of the tray 21. Correspondingly, a plurality of positioning holes 25a are provided in the cover plate 25, and the number of the positioning holes 25a and the boss 21c are The number is equal.

In the present embodiment, the diameter of the lower surface of the tray 21 is equal to or slightly larger than the diameter of the upper surface of the chuck 23, so that the tray 21 can completely cover the chuck 23 and be reliably sealed with the chuck 23, so that not only the refrigerant can be prevented. The medium leaks and the plasma is prevented from damaging the upper surface of the chuck 23.

In the present embodiment, as shown in FIG. 2, the upper electrode includes an inductive coupling coil (not shown), the inductive coupling coil is disposed above the dielectric window 27, and the dielectric window 27 is disposed at the top of the reaction chamber 20. The inductive coupling coil is connected to the excitation RF power source 13 through the first matching unit 12, and the bias RF power source 18 is connected to the chuck 23 through the second matching unit 17, and the RF power is excited. Source 13 inputs RF energy into reaction chamber 20 to cause the process gas to be ionized to form plasma 10. The bias RF power source 18 is used to generate a radio frequency bias on the surface of the wafer S to attract ions to process the surface of the wafer S.

It should be noted that although in the above embodiment, the excitation RF power source 13 and the bias RF power source 18 are two mutually independent RF power sources. However, the present invention is not limited thereto. In practical applications, the excitation RF power source 13 and the bias RF power source 18 may also be replaced by a polarization power supply, but the RF power supply needs to have two independent RF power output terminals.

It should be noted that, in the above embodiment, the DC power supply 24 includes a positive terminal, a negative terminal, and a common terminal, and the common terminal is grounded or the common terminal is grounded via the casing; but in practical applications, the DC power supply 24 can also be used. Adopt other structures. For example, the DC power source 24 may include only the positive terminal and the common terminal, and in use, connect the tray electrode to the positive terminal, connect the chuck electrode to the common terminal, or directly ground. As another example, the DC power source 24 can include only the negative terminal and the common terminal, and in use, connect the tray electrode to the negative terminal, connect the chuck electrode to the common terminal, or directly ground. For another example, the DC power source 24 may include only the positive terminal and the negative terminal, and in use, the tray electrode is connected to the positive terminal, and the chuck electrode may be directly grounded, and the chuck electrode may be connected to the negative terminal. The terminal is grounded to the negative terminal; or the tray electrode is connected to the negative terminal, and the chuck electrode can be directly grounded, and the chuck electrode can be connected to the positive terminal and the positive terminal can be grounded.

The plasma processing apparatus provided by the above embodiments may be an LED etching machine for performing an etching process; or ITO (indium tin oxide) Physical vapor deposition apparatus for preparing an ITO film. The wafer may be a sapphire substrate or a processed device of other materials. For example, the material of the wafer may also be tantalum or tantalum oxide.

The electrostatic adsorption force between the tray 21 and the wafer S and the electrostatic adsorption force between the tray 21 and the chuck 23 in the present embodiment will be described below.

The tray electrode in the tray 21 is turned on with the positive electrode of the DC power source 24, assuming that the tray electrode to ground (GND) voltage is E1, and E1 is equal to the voltage E between the DC power source 24 and the ground (GND). After the plasma in the reaction chamber 20 is illuminated, a conductive layer is formed on the upper surface of the wafer S, and the voltage between the conductive layer and the ground (GND) is E2. Since the resistance of the plasma is small, E2 is approximately equal to zero. Therefore, the voltage between the tray electrode and the upper surface of the wafer S is E3 = E1 - E2 E1=E. The chuck electrode in the chuck 23 is turned on with the negative electrode of the DC power source 24, and the voltage difference between the tray electrode and the chuck electrode is E.

A first capacitor C1 is formed between the chuck electrode and the tray electrode, and a second capacitor C2 is formed between the tray electrode and the upper surface of the wafer S. Since the upper surface of the wafer S is approximately grounded, and the chuck electrode is grounded (GND), the first The capacitor C1 and the second capacitor C2 are in a parallel relationship, assuming that the distance between the chuck electrode and the tray electrode is d1, and the distance between the tray electrode and the upper surface of the wafer S is d2. Then, according to Coulomb's law, the electrostatic adsorption force F ₁ between the chuck electrode and the tray electrode (ie, between the chuck 23 and the tray 21) is:

The electrostatic adsorption force F ₂ between the tray electrode (ie, the tray 21) and the wafer S is:

As can be seen from the above, since the first capacitor C1 and the second capacitor C2 are in a parallel relationship, the voltage difference between the chuck electrode and the tray electrode and the voltage difference between the tray electrode and the wafer S are both E. Thus, the tray chuck 23 and the electrostatic attraction force F between the tray ₂₁₁ and the electrostatic attractive force between the wafer 21 and the larger S F _2.

4 is a cross-sectional view showing a portion of a structure of a plasma processing apparatus according to another embodiment of the present invention. As shown in FIG. 4, the tray 21 carries a plurality of wafers S. Correspondingly, a boss 21c having the same number as the number of wafers S is provided on the carrying surface of the tray 21, and the number of wafers S is equally provided on the cover plate 25. The positioning hole 25a is disposed, and the positioning hole 25a is disposed at a position opposite to the position of the boss 21c. In use, each of the bosses 21c and the positioning holes 25a corresponds to a wafer S, that is, each of the positioning holes 25a positions one wafer S, and the wafer S is placed at the top end of the boss 21c.

The plasma processing apparatus provided in the above embodiment places the tray on the chuck, the board and the chuck are electrically insulated, and the tray and the chuck are electrically insulated from the plasma, and the tray electrode and the positive output of the DC power source or The negative output terminal is electrically connected, and the chuck electrode is grounded so that there is a voltage difference between the tray and the chuck, that is, an electrostatic attraction force is generated between the tray and the chuck, thereby fixing the tray to the upper surface of the chuck; There is a voltage difference between the tray and the wafer, that is, an electrostatic adsorption force is generated between the tray and the wafer to fix the wafer on the upper surface of the tray. This method of fixing the wafer and the tray is not only easy to operate, but also highly reliable, and the structure is Simple, low cost and not easily damaged.

It is to be understood that the above embodiments are merely exemplary embodiments employed to explain the principles of the invention, but the invention is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the invention. These modifications and improvements are also considered to be within the scope of the invention.

10‧‧‧ Plasma

12‧‧‧First matcher

13‧‧‧Incentive RF power supply

17‧‧‧Second matcher

18‧‧‧Bias RF power supply

20‧‧‧Reaction chamber

21‧‧‧Tray

21a‧‧‧Tray refrigerant channel

21c‧‧‧ boss

23‧‧‧ chuck

23a‧‧‧First Chuck Refrigerant Channel

23b‧‧‧Second chuck refrigerant channel

24‧‧‧DC power supply

25‧‧‧ Cover

25a‧‧‧Positioning holes

27‧‧‧Media window

30, 30'‧‧‧ Filter circuit

A‧‧‧ chuck ring groove

B‧‧‧Tray ring groove

S‧‧‧ wafer

L21‧‧‧First filter inductor

C21‧‧‧First filter capacitor

L22‧‧‧Second filter inductor

C22‧‧‧Second filter capacitor

Claims (16)

A plasma processing apparatus comprising a reaction chamber, an excitation RF power source, a DC power source, an upper electrode, and a wafer supporting device disposed in the reaction chamber opposite to the upper electrode, the upper electrode being connected to the excitation RF power source To generate plasma in the reaction chamber, the wafer support device includes a tray for carrying a wafer and a chuck, and a tray electrode is disposed in the tray, wherein the tray is placed on the chuck and Electrically insulated between the two, and the tray and the chuck are electrically insulated from the plasma, the tray electrode is electrically connected to the positive output terminal or the negative output terminal of the DC power source, and the chuck is provided A chuck electrode, the chuck electrode being grounded such that a voltage difference exists between the tray and the chuck and between the tray and the wafer. The plasma processing apparatus of claim 1, wherein the DC power source comprises a positive output terminal, a negative output terminal, and a common terminal, wherein the common terminal is grounded; or the DC power supply includes a positive output terminal and a common End, the common end is grounded; or the DC power source includes a negative output terminal and a common terminal, and the common terminal is grounded. The plasma processing apparatus according to claim 1, wherein the direct current power source includes a positive output terminal and a negative output terminal, and the tray electrode is electrically connected to a positive output terminal of the direct current power source, and the negative output terminal Grounding; or, the tray electrode is electrically connected to a negative output end of the direct current power source, and the positive output end is grounded. The plasma processing apparatus according to claim 1, characterized in that a filter circuit is connected in series between the tray electrode and the DC power source; and / Or, a filter circuit is connected in series between the chuck electrode and the ground. A plasma processing apparatus according to claim 4, wherein the filter circuit is a high frequency high voltage resistor. The plasma processing apparatus of claim 4, wherein the filter circuit is a filter circuit having a radio frequency attenuation of less than -10 dB. The plasma processing apparatus according to claim 6, comprising: n inductors and n capacitors, wherein the n inductors are connected in series, the n capacitors are connected in parallel, and the n inductors are connected in series and then n capacitors are connected in parallel, and one end of the n capacitors connected in parallel is grounded, n An integer of 1. The plasma processing apparatus according to claim 1, wherein the tray is made of a conductive material, and an insulating material is coated on a surface of the conductive material, the conductive material serving as the tray electrode; the card The disk is made of a conductive material, and an insulating material is coated on the surface of the conductive material, and the conductive material serves as the chuck electrode. A plasma processing apparatus according to claim 8, wherein the insulating material forms an insulating layer on a surface of the conductive material. A plasma processing apparatus according to claim 9, wherein the insulating layer is formed on the surface of the conductive material by spraying or anodizing. The plasma processing apparatus according to claim 1, wherein the tray is made of an insulating material, and a tray electrode is embedded inside the insulating material, the tray electrode is made of a conductive material; and the chuck is insulated. The material is fabricated, and a chuck electrode is embedded inside the insulating material, and the chuck electrode is made of a conductive material. A plasma processing apparatus according to claim 1, characterized in that A first chuck refrigerant passage for cooling the chuck is disposed in the chuck, and the chuck is cooled by introducing a first cold medium into the first chuck refrigerant passage. The plasma processing apparatus according to claim 1, wherein a second chuck refrigerant passage penetrating through the thickness direction thereof is further disposed in the chuck, and a chuck ring is disposed on an upper surface of the chuck a groove, the chuck annular groove is in communication with the second chuck refrigerant passage; a tray refrigerant passage penetrating through a thickness direction thereof is disposed in the tray, the tray refrigerant passage and the chuck annular groove In communication, the second cold medium is sequentially supplied to the back surface of the wafer via the second chuck refrigerant passage, the chuck annular groove, and the tray refrigerant passage to cool the wafer. The plasma processing apparatus according to claim 1, further comprising a cover plate disposed on a bearing surface of the tray, wherein a positioning hole penetrating the thickness thereof is disposed in the cover plate, The cover plate is configured to protect a region on the tray bearing surface from which the wafer is not placed from the bombardment of the plasma; a boss is disposed on the bearing surface of the tray and opposite to the positioning hole, and the wafer is disposed on the The top of the boss. A plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is an LED etching machine or an ITO physical vapor deposition apparatus. The plasma processing apparatus according to claim 1, wherein the wafer is made of sapphire, ruthenium or iridium oxide.