TWI392043B - A substrate holding member and a substrate processing apparatus - Google Patents

Description

Substrate holding member and substrate processing device

The present invention relates to a substrate holding member that holds a substrate and holds the substrate, and a substrate processing apparatus including the substrate holding member.

For example, in the process of a semiconductor device, for example, a plasma etching process and a film forming process are performed.

These plasma treatments using plasma are carried out by a conventional plasma processing apparatus. The plasma processing apparatus includes, for example, a high-frequency power upper electrode for applying plasma, and a susceptor for holding the substrate, for example, in the processing container. Thereafter, the inside of the processing container is depressurized to a specific pressure, the processing gas is supplied into the processing container, and high-frequency power for plasma generation is applied to the upper electrode, thereby generating plasma in the processing container, and by using the The plasma etches the film on the substrate.

The plasma treatment is carried out under high temperature conditions for generating plasma, and in order to maintain a certain processing state of the substrate, for example, the temperature of the substrate needs to be maintained constant. Therefore, the temperature of the substrate is controlled by the susceptor for holding the substrate, for example, by circulating the supply of the refrigerant.

In the case of the susceptor, the upper surface of the substrate is formed to be smaller than the substrate. In this case, the outer peripheral portion of the substrate is exposed from the upper surface of the susceptor (see, for example, Patent Document 1). This is for preventing the upper surface of the susceptor from being exposed from the upper electrode during the etching process, and causing loss due to plasma or the like.

[Patent Document 1] Japanese Patent Laid-Open No. 11-121600

However, when the outer peripheral portion of the substrate is exposed from the susceptor as described above, the heat energy entering the outer peripheral portion of the substrate during the treatment is high, and the cooling by the susceptor on the outer peripheral portion of the substrate is not sufficiently performed. Therefore, the closer the substrate on the susceptor is to the outer peripheral portion, the higher the temperature, and the temperature in the surface of the substrate cannot be kept uniform. When the temperature in the surface of the substrate is not kept uniform, for example, the degree of variation in the etching characteristics in the surface of the substrate is increased, or the line width of the central portion and the outer peripheral portion of the substrate is different, for example.

The present invention has been made in view of the above problems, and an object of the invention is to maintain the in-plane temperature of the substrate uniformly in a substrate holding member such as a susceptor that controls the temperature of the substrate while holding the substrate.

In order to achieve the above object, the present invention provides a substrate holding member which is held by placing a substrate and performing temperature control of the substrate by heat transfer between the substrate and the substrate holding surface, and is characterized in that it is smaller than a substrate holding surface of the substrate; and a heat transfer rate between the substrate and the substrate holding surface; an intermediate portion between the central region and the outer peripheral region of the substrate holding surface is lower with respect to the central region and the outer peripheral region, and the outer peripheral region is opposite It is higher in the above central area.

According to the present invention, the in-plane temperature of the substrate held on the substrate holding surface can be uniformly maintained.

The central region of the substrate holding surface may be in the range of 80 to 90% of the substrate radius when viewed from the center of the substrate to be held.

The heat transfer rate between the substrate and the substrate holding surface can be set by changing the contact area between the substrate and the substrate holding surface.

A plurality of convex portions for supporting the substrate are formed on the substrate holding surface; and a heat transfer rate between the substrate and the substrate holding surface can be changed by changing the number of each unit area of the convex portion or each convex portion Set with the contact area of the substrate.

The heat transfer rate between the substrate and the substrate holding surface can be set by changing the material of the substrate holding surface.

The heat transfer rate between the substrate and the substrate holding surface can be set by changing the surface roughness of the substrate holding surface.

According to another aspect of the invention, there is provided a substrate processing apparatus including a substrate holding member that holds and holds a substrate, and performs substrate transfer by heat transfer between the substrate and the substrate holding surface. The temperature control is characterized in that the substrate holding member has a substrate holding surface smaller than the substrate; the heat transfer rate between the substrate and the substrate holding surface, and the intermediate portion between the central region and the peripheral region of the substrate holding surface The outer peripheral region and the outer peripheral region are lower, and the outer peripheral region is higher with respect to the central region.

According to the present invention, since the in-plane temperature of the substrate on the substrate holding surface can be uniformly maintained, the processing of the substrate can be performed uniformly in the plane to improve the yield.

The following is a description of preferred embodiments of the invention. Figure 1 reveals A longitudinal cross-sectional view showing a schematic configuration of a parallel plate type plasma processing apparatus 1 including a substrate holding member of the present invention.

The plasma processing apparatus 1 has, for example, a processing container 10 having a substantially cylindrical shape. A processing chamber S is formed in the interior of the processing container 10. The treatment container 10 is formed, for example, of an aluminum alloy, and the inner wall is covered with an aluminum oxide film or a ruthenium oxide film. The processing vessel 10 is grounded.

A cylindrical susceptor support 12 is provided on the central bottom of the processing container 10 via the insulating plate 11. On the susceptor support 12, a susceptor 13 as a substrate holding member held as a substrate W is supported. The susceptor 13 constitutes a lower electrode.

An annular refrigerant chamber 14 is formed in the interior of the susceptor support 12 . The refrigerant chamber 14 is in communication with a temperature control cooler (not shown) provided on the outside of the processing container 10 through the pipes 14a and 14b. In the refrigerant chamber 14, the refrigerant is circulated and supplied through the pipes 14a and 14b, and the temperature of the susceptor 13 is adjusted by the circulation supply. Thereby, the temperature of the substrate W placed on the susceptor 13 is controlled.

The susceptor 13 is formed, for example, of an aluminum alloy, for example, of alumina (Al ₂ O ₃ ). The susceptor 13 is formed, for example, in a substantially disk shape in which the center portion protrudes upward. The protruding portion of the central portion of the susceptor 13 serves as the electrostatic chuck 15 . An electrode layer 17 connected to the DC power source 16 is provided inside the electrostatic chuck 15 to apply a DC voltage from the DC power source 16 to the electrode layer 17 to generate a Coulomb force, whereby the substrate W can be adsorbed.

Mounted on the upper surface of the electrostatic chuck 15 of the susceptor 13 The substrate holding surface 20 of the substrate W. The substrate holding surface 20 is formed, for example, in a circular shape having an inner diameter smaller than the inner diameter of the substrate W placed thereon. When the substrate W is placed on the substrate holding surface 20, the outer peripheral portion of the substrate W protrudes outward from the end portion of the substrate holding surface 20. For example, as shown in FIGS. 2 and 3, the substrate holding surface 20 includes a peripheral ring 21 that surrounds the outermost circumference in a ring shape, and a plurality of convex portions 22 that are cylindrical. The outer peripheral ring 21 and the upper surface of the convex portion 22 are formed to be flat at the same height, and are in contact with the substrate W when the substrate W is placed. Therefore, the substrate W is supported by the outer peripheral ring 21 and the convex portion 22 of the substrate holding surface 20.

The substrate holding surface 20 is formed from the center portion toward the outer peripheral portion so that the heat transfer rate with the substrate W is initially constant, and then decreases and then rises. For example, as shown in FIG. 4, the substrate holding surface 20 is divided into a central region R1 from the center of the substrate W placed thereon to about 80% of the radius K of the substrate W, and when viewed from the center of the substrate W. The intermediate region R2 located in the range of 80 to 90% of the radius K of the substrate W and the outer peripheral region R3 in the range of 90 to 98% of the radius K of the substrate W when viewed from the center of the substrate W. The heat transfer rate between the substrate W and the substrate holding surface 20 is set in each of the regions R1 to R3. The heat transfer rate referred to herein means the average heat transfer rate of each of the regions R1 to R3.

In the center region R1, a plurality of convex portions 22 are equally arranged as shown in FIGS. 2 and 3 . In the plane of the central region R1, the heat transfer rate is constant. In the intermediate portion R2, the convex portion 22 is disposed such that the number of the unit areas of the plurality of convex portions 22 is smaller than the central portion R1. Thereby, the contact ratio between the convex portion 22 of the intermediate portion R2 and the substrate W ("contact Since the area of contact "/all areas in the area" is smaller than the center area R1, the heat transfer rate of the intermediate area R2 to the substrate W is lower than that of the center area R1. Further, the heat transfer rate of the intermediate portion R2 to the substrate W is set to be about 90% of the central region R1.

In the outer peripheral region R3, a plurality of convex portions 22 and outer peripheral rings 21 are disposed such that the contact ratio with the substrate W rises more than the central region R1 and the intermediate portion R2. For example, the number of units per unit area of the convex portion 22 is increased or the thickness of the outer peripheral ring 21 is increased, whereby the contact ratio can be increased. Thereby, the heat transfer rate of the outer peripheral region R3 with the substrate W can be made higher than the central region R1 and the intermediate portion R2.

As shown in Fig. 1, the gas supply line 30 passing through the susceptor 13 and the susceptor support 12 passes through the substrate holding surface 20. Thereby, when the substrate W is placed on the substrate holding surface 20, a heat transfer gas such as He gas can be supplied to the space between the substrate W and the electrostatic chuck 15 .

An annular focus ring 31 is provided on the outer circumference of the electrostatic chuck 15 of the susceptor 13. The focus ring 31 is formed to surround the substrate W placed on the susceptor 13. The focus ring 31 is formed, for example, of a conductive material.

The first high frequency power source 41 is electrically connected to the susceptor 13 via the integrator 40. The first high-frequency power source 41 can be applied to the susceptor 13 by, for example, a range of 2 to 20 MHz, for example, a high-frequency power of a frequency of 2 MHz. By the first high-frequency power source 41, a self-bias potential for pulling ions in the plasma to the side of the substrate W can be generated.

The receiver 13 is electrically connected to ground the high frequency of the second high frequency power source 71 from the side of the upper electrode 50 to be described later. High pass filter 42.

Above the susceptor 13, a counter electrode 13 is provided parallel to the susceptor 13 and opposed to the upper electrode 50. A plasma generating space is formed between the susceptor 13 and the upper electrode 50.

The upper electrode 50 constitutes a spray head that ejects the processing gas onto the substrate W placed on the susceptor 13. The upper electrode 50 is composed of, for example, an electrode plate 51 opposed to the susceptor 13 and an electrode support 52 for supporting the electrode plate 51. The electrode support 52 is formed, for example, in a hollow cylindrical shape, and an electrode plate 51 is provided on the lower surface. A plurality of gas ejection holes 51a are formed in the electrode plate 51, and the processing gas introduced into the electrode support 52 can be ejected from the gas ejection holes 51a.

A gas supply pipe 60 for introducing a processing gas into the upper electrode 50 is connected to a central portion of the upper surface of the electrode support 52 of the upper electrode 50. The gas supply pipe 60 is connected to a gas supply source 61 that passes through the upper surface of the processing container 10. At the contact portion between the gas supply pipe 60 and the processing container 10, an insulating material 62 is interposed.

The second high frequency power source 71 is electrically connected to the upper electrode 50 via the integrator 70. The second high-frequency power source 71 can be applied to the upper electrode 50, for example, by outputting 40 M or more, for example, a high-frequency power of a frequency of 60 MHz. The plasma of the processing gas can be generated in the processing container 10 by the second high-frequency power source 71.

The upper electrode 50 is electrically connected to a low-pass filter 72 for bringing the high frequency of the first high-frequency power source 41 from the susceptor 13 side to the ground.

An exhaust port 80 is formed in the bottom of the processing container 10. The exhaust port 80 is connected to an exhaust device 82 having a vacuum pump or the like through an exhaust pipe 81. By means of the exhaust device 82, the inside of the processing container 10 can be depressurized to a desired pressure.

A transfer port 90 of the substrate W is formed on the side wall of the processing container 10, and a gate valve 90 is provided on the transfer port 90. By opening the gate valve 90, the substrate W can be fed and sent out in the processing container 10. .

In the etching process performed by the plasma processing apparatus 1 configured as described above, the substrate W is first transferred into the processing container 10, and placed on the substrate holding surface 20 of the susceptor 13 to be adsorbed. At this time, the susceptor 13 is previously adjusted to a specific temperature by the circulating refrigerant of the susceptor support table 12. Due to the heat transfer from the susceptor 13, the substrate W on the substrate holding surface 20 is also adjusted to a specific temperature. The inside of the processing chamber S is then decompressed to a specific pressure by, for example, exhaust gas from the exhaust pipe 81. Process gas is supplied into the process chamber S from among the upper electrodes 50. The high-frequency power is applied to the upper electrode 50 by the second high-frequency power source 71, and the processing gas in the processing chamber S is plasma-formed. Further, high frequency power is applied to the susceptor 13 by the first high frequency power source 41, and the charged particles in the plasma are guided to the substrate W side. The film on the substrate W is etched by the action of the plasma.

Next, the uniformity of the in-plane temperature of the substrate when the susceptor 13 is used in the present embodiment is verified. Fig. 5 is a view showing the in-plane heat transfer rate distribution of the substrate W and the substrate holding surface 20 and the in-plane temperature distribution of the substrate W after temperature adjustment on the substrate holding surface 20.

Curve A of Figure 5 shows that it is assumed in all areas The in-plane temperature distribution of the substrate W when the heat transfer rate between the substrate W and the substrate holding surface of 13 is uniform. In this case, it was confirmed that the temperature of the outer peripheral portion of the substrate W significantly increased. Curve B shows the heat transfer rate distribution when the heat transfer rate between the substrate W and the substrate holding surface increases from the center portion of the substrate holding surface to the outer peripheral portion, and the curve C indicates the heat transfer rate distribution in the curve B. The in-plane temperature distribution of the substrate W at the time. In the case of the curve C, although the temperature rise of the outer peripheral portion of the substrate W is suppressed more than in the case of the curve A, a large temperature drop is observed from the central portion to the outer peripheral portion of the substrate W in the opposite direction.

The curve D indicates the heat transfer rate when the heat transfer rate with the substrate W is increased in the order of the intermediate portion R2 < the central region R1 < the outer peripheral region R3, as in the substrate holding surface 20 of the susceptor 13 of the present embodiment. Distribution, curve E shows the in-plane temperature distribution of the substrate W on the substrate holding surface 20 of the present embodiment. In the case of the curve E, it can be confirmed that the temperature drop from the center portion to the outer peripheral portion of the substrate W is improved in the case of the curve C, and the maximum temperature difference in the substrate surface is also suppressed within the range of ±1 °C. .

According to the present embodiment, the heat transfer rate of the substrate W and the substrate holding surface 20 can be set to the intermediate portion R2 <center by changing the number of the unit area per unit area of the convex portion 22 of the substrate holding surface 20 of the susceptor 13. Since the region R1 < the outer peripheral region R3, the in-plane temperature of the substrate W can be kept uniform in the etching process of the plasma processing apparatus 1, and a uniform etching process can be performed in the substrate surface.

According to the above embodiment, each unit area of the convex portion 22 is The heat transfer rate between the substrate holding surface 20 and the substrate W in each of the regions R1 to R3 is set, but the convex portions 22 may be uniformly disposed on the substrate holding surface 20, and the contact area between the respective convex portions 22 and the substrate W may be changed. That is, the area above the convex portions 22, thereby setting the heat transfer rate between the substrate holding surface 20 and the substrate W of the respective regions R1 to R3.

Further, the heat transfer rate between the substrate W and the substrate holding surface 20 of each of the regions R1 to R3 can be set by changing the material of each of the regions R1 to R3 of the substrate holding surface 20. For example, when the substrate holding surface 20 is composed of a material mainly composed of alumina, a different amount of aluminum nitride (AlN) can be added to the material components of the respective regions R1 to R3 of the substrate holding surface 20, whereby To set the heat transfer rate of each zone R1~R3. In this case, the more aluminum nitride is added in the order of the intermediate region R2, the central region R1, and the outer peripheral region R3, and the heat transfer rate is set in accordance with the intermediate region R2, the central region R1, and the outer peripheral region R3. Gradually improve. Further, in this case, the substrate holding surface 20 may be a flat surface having no unevenness as shown in FIG.

Further, the heat transfer rate of each of the regions R1 to R3 can be set by changing the surface roughness of each of the regions R1 to R3 of the substrate holding surface 20. In this case, the substrate holding surface 20 is formed such that the surface roughness gradually decreases in accordance with the intermediate region R2, the central region R1, and the outer peripheral region R3, and the heat transfer rate is set to be in accordance with the intermediate region R2 and the central region R1. The order of the peripheral region R3 is gradually increased. In this case, the substrate holding surface 20 may be a flat surface having no irregularities.

The preferred embodiment of the present invention will be described above with reference to the drawings. However, the invention is not limited to this example. It is to be understood that various modifications and changes can be made within the scope of the invention as described in the appended claims, and such modifications and modifications are also within the scope of the invention. The present invention is not limited to this example, and various types can be adopted. For example, in the present embodiment, the convex portion 22 of the substrate holding surface 20 has a cylindrical shape, but may have other shapes such as a quadrangular prism. Further, on the substrate holding surface 20, a ring of the inner circumference may be formed on the inner side of the outer peripheral ring 21. Further, both the high-frequency power source for generating the self-bias potential and the high-frequency power source for generating the plasma may be connected to the susceptor 13 which serves as the lower electrode. In the above embodiment, the susceptor 13 having the substrate holding surface 20 is provided for the plasma processing apparatus 1 for etching, but the substrate holding member of the present invention can also be applied to the plasma processing for performing the film forming process. Devices, and other substrate processing devices that do not employ plasma.

Industrial availability:

In the substrate holding member for controlling the temperature of the substrate, the present invention is extremely useful when the in-plane temperatures of the substrates are maintained to match.

1‧‧‧Plastic processing unit

10‧‧‧Processing container

12‧‧‧Resistor support table

13‧‧‧ susceptor

14‧‧‧The refrigerant room

14a, 14b‧‧‧ piping

15‧‧‧Electrostatic adsorption tray

16‧‧‧DC power supply

17‧‧‧Electrical layer

20‧‧‧ substrate holding surface

21‧‧‧ peripheral ring

22‧‧‧ convex

30‧‧‧ gas supply line

31‧‧‧ Focus ring

40‧‧‧ Integrator

41‧‧‧1st high frequency power supply

42‧‧‧High-pass filter

50‧‧‧Upper electrode

51‧‧‧Electrode plate

51a‧‧‧ gas ejection hole

52‧‧‧Electrode support

60‧‧‧ gas supply pipe

61‧‧‧ gas supply

62‧‧‧Insulation

70‧‧‧ Integrator

71‧‧‧2nd high frequency power supply

72‧‧‧ low pass filter

80‧‧‧Exhaust port

81‧‧‧Exhaust pipe

82‧‧‧Exhaust device

R1‧‧‧ central area

R2‧‧‧ intermediate area

R3‧‧‧Outer Area

W‧‧‧Substrate

Fig. 1 is a longitudinal sectional view showing a schematic configuration of a plasma processing apparatus.

Fig. 2 is a plan view showing the substrate holding surface.

Figure 3 is a longitudinal cross-sectional view showing the electrostatic chuck of the susceptor.

Figure 4 is a diagram showing the substrate retention for illustrating the area of the substrate holding surface. The pattern of the face.

Fig. 5 is a view showing the heat transfer rate distribution of the substrate holding surface and the in-plane temperature distribution of the substrate.

Fig. 6 is a longitudinal sectional view showing the electrostatic chuck in the case where the substrate holding surface is flat.

20‧‧‧ substrate holding surface

21‧‧‧ peripheral ring

22‧‧‧ convex

R1‧‧‧ central area

R2‧‧‧ intermediate area

R3‧‧‧Outer Area

W‧‧‧Substrate

Claims (4)

A substrate holding member for holding and holding a substrate, and performing temperature control of the substrate by heat transfer between the substrate and the substrate holding surface, wherein the substrate has a substrate holding surface smaller than the substrate; The heat transfer rate of the substrate holding surface is set by changing the material of the substrate holding surface, and the intermediate portion between the central region and the outer peripheral region of the substrate holding surface is lower with respect to the central region and the outer peripheral region, The peripheral area is higher relative to the above central area. A substrate holding member for controlling temperature of a substrate by heat transfer between a substrate and a substrate holding surface, characterized in that: a substrate holding surface smaller than the substrate; and a heat transfer rate between the substrate and the substrate holding surface is The setting is performed by changing the surface roughness of the substrate holding surface, and the intermediate portion between the central region and the outer peripheral region of the substrate holding surface is lower with respect to the central region and the outer peripheral region, and the outer peripheral region is opposite to the central region It is higher. The substrate holding member according to the first or second aspect of the invention, wherein the central region of the substrate holding surface is in a range of 80 to 90% of the substrate radius as viewed from the center of the substrate to be held. Inside. A substrate processing apparatus comprising the substrate holding member according to any one of claims 1 to 3.