Electrostatic chuck device capable of improving thickness uniformity of deposited film

Abstract

The utility model relates to an electrostatic chuck device capable of improving thickness uniformity of a deposited film. The electrostatic chuck device comprises a carrying table, an electrode unit and a terminal unit, the carrying platform comprises a carrying surface. The electrode unit is arranged in the carrying platform and is used for generating static electricity. The terminal unit is arranged on the electrode unit and located on the side, away from the bearing face, of the electrode unit. The terminal unit is electrically connected with the electrode unit, and the relative permeability of the terminal unit is smaller than 50. The electrostatic chuck device is used for bearing a substrate to be sputtered, and the terminal unit with the relative magnetic conductivity smaller than 50 is selected to be arranged on the electrode unit, so that the terminal unit can be prevented from being magnetized; therefore, thick and thin singular points generated on a film layer corresponding to the terminal unit on the substrate due to the fact that ions are attracted by the terminal unit in the deposition process are avoided, the thickness range is reduced, and the uniformity of a deposited film on the substrate is improved.

Description

Technical Field

[0001] The utility model relates to an electrostatic chuck, in particular to an electrostatic chuck device capable of improving the uniformity of deposited film thickness. Background Art

[0002] See Figure 1 A conventional sputtering machine 7 in the semiconductor industry includes a chamber 71, a magnet 72, a target 73 located below the magnet 72, an alternating current 74 electrically connected to the target 73, and an electrostatic chuck device 75. The sputtering machine 7 deposits a metal layer on a substrate 8 on the electrostatic chuck device 75 using a physical vapor deposition (PVD) method.

[0003] The sputtering machine 7 uses a robotic arm (not shown) to grab the substrate 8 onto the electrostatic chuck device 75, and then uses plasma to bombard the target material 73 with ions, thereby knocking out ions on the surface of the target material 73 and depositing them on the substrate 8.

[0004] The electrostatic chuck device 75 is used to carry and adsorb the substrate 8. The electrostatic chuck device 75 has a disk body 751, two electrodes 752 disposed in the disk body 751, and two terminals 753 respectively disposed on the electrodes 752. The terminals 753 are electrically connected to a power supply (not shown). The power supply provides a positive power supply and a negative power supply to the electrodes 752 via the terminals 753 to generate static electricity. The disk body 751 is made of aluminum nitride (AlN) with a thermal expansion coefficient of 4×10 -6 / K. Each of the terminals 753 is made of nickel-base alloy with a relative magnetic permeability of 600 and a thermal expansion coefficient greater than 6×10 -6 / K.

[0005] See Figure 2 ,for Figure 1A magnified schematic diagram of the deposition process at the area enclosed by the dotted circle. During the titanium nitride (TiN) deposition process, positively charged titanium nitride ions 76 diffuse in the chamber 71 and flow from the center of the substrate 8 toward the edge of the substrate 8. Because the terminals 753 have a high relative permeability and are easily magnetized by the magnetic field generated by the magnet 72, the titanium nitride ions 76 are attracted by the magnetic field 77 generated by the corresponding terminals 753 when passing over the corresponding terminals 753. This causes the film 78 to be thicker near the center of the substrate 8 and thinner away from the center of the substrate 8. This creates singularity points on the film 78 where the thicker and thinner portions intersect. These singularity points result in uneven thickness deposition on the substrate 8, increasing the thickness range and reducing the deposition quality of the film 78.

[0006] In addition, the terminal 753 has a larger thermal expansion coefficient than the disk body 751 and is more susceptible to thermal expansion and contraction than the disk body 751. This can easily cause the disk body 751 to crack during the processing of the electrostatic suction cup device 75, making processing more difficult. Utility Model Content

[0007] The purpose of the present utility model is to provide an electrostatic chuck device capable of improving at least one of the above-mentioned shortcomings and improving the uniformity of the deposited film thickness.

[0008] The utility model is an electrostatic chuck device capable of improving the uniformity of deposited film thickness, comprising a carrier, an electrode unit, and a terminal unit; the carrier includes a carrying surface, the electrode unit is arranged in the carrier and is used to generate static electricity, the terminal unit is arranged in the electrode unit and is located on a side of the electrode unit away from the carrying surface, the terminal unit is electrically connected to the electrode unit and has a relative magnetic permeability of less than 50.

[0009] In the electrostatic chuck device capable of improving the uniformity of deposited film thickness of the utility model, the material of the terminal unit is molybdenum (Mo) or tungsten (W).

[0010] The utility model discloses an electrostatic chuck device capable of improving the uniformity of deposited film thickness. The electrode unit includes a first disc-shaped electrode member and a second electrode member surrounding the first electrode member. The terminal unit includes two conductive terminals respectively arranged on the first electrode member and the second electrode member.

[0011] In the electrostatic chuck device capable of improving the uniformity of deposited film thickness of the present invention, the material of each conductive terminal is molybdenum (Mo) or tungsten (W).

[0012] The utility model discloses an electrostatic chuck device capable of improving the uniformity of the deposited film thickness, wherein the carrier is made of aluminum nitride (AlN), and the thermal expansion coefficient of the terminal unit is less than 4.5×10 -6 / K.

[0013] The electrostatic chuck device capable of improving the uniformity of the thickness of the deposited film of the present invention further comprises a heater arranged in the carrier.

[0014] The utility model discloses an electrostatic chuck device capable of improving the uniformity of the thickness of a deposited film, wherein a plurality of air holes are formed on the carrying surface of the carrying platform.

[0015] The beneficial effect of the present invention is that the electrostatic suction cup is used to carry a substrate to be sputtered. By selecting the terminal unit with a relative magnetic permeability less than 50 and setting it on the electrode unit, the terminal unit can be prevented from being magnetized, so as to avoid the ions being attracted by the terminal unit during the deposition process, resulting in the film corresponding to the terminal unit on the substrate producing singular points of excessive thickness and excessive thinness, reducing the thickness range, and improving the uniformity of the deposited film on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of an existing electrostatic chuck device used in a sputtering machine;

[0017] Figure 2 is a schematic diagram of the sputtering machine depositing ions onto a substrate on the electrostatic chuck device;

[0018] Figure 3 This is a schematic diagram of an embodiment of the electrostatic chuck device of the utility model capable of improving the uniformity of deposited film thickness being used in a sputtering machine;

[0019] Figure 4 is a schematic diagram of the sputtering machine depositing ions on a substrate in the embodiment;

[0020] Figure 5 It is a schematic diagram of partitions of a substrate provided in the embodiment. DETAILED DESCRIPTION

[0021] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0022] See Figure 3 An embodiment of the electrostatic chuck device of the present invention that can improve the uniformity of the thickness of the deposited film includes a carrier 1, an electrode unit 2 arranged in the carrier 1 and used to generate static electricity, a terminal unit 3 arranged in the electrode unit 2, and a heater 4 arranged in the carrier 1.

[0023] The carrier 1 is suitable for 300mm wafer processing. The carrier 1 includes a carrying surface 11, two air inlet channels 12, and an air outlet channel 13. A plurality of air holes 14 are formed on the carrying surface 11 to connect the air inlet channels 12 and the air outlet channels 13. The air inlet channel 12 is connected to a gas source (not shown). In this embodiment, the carrier 1 is made of aluminum nitride (AlN) with a thermal expansion coefficient of 4×10 -6 / K.

[0024] The electrode unit 2 includes a first disc-shaped electrode member 21 and a second ring-shaped electrode member 22 surrounding the first electrode member 21 .

[0025] The terminal unit 3 is located on a side of the electrode unit 2 away from the carrying surface 11. Specifically, the terminal unit 3 includes two conductive terminals 31, which are respectively provided on the first electrode member 21 and the second electrode member 22 and electrically connected to the first electrode member 21 and the second electrode member 22. An axis L extending up and down and passing through the center of the carrier 1 is defined, and the radial distances between the conductive terminal 31 and the axis L are 80 mm and 128 mm, respectively. In this embodiment, the first electrode member 21, the second electrode member 22 and the heater 4 are made of non-ferromagnetic material.

[0026] The conductive terminal 31 is electrically connected to a power source (not shown). The power source provides a positive power source and a negative power source to the first electrode member 21 and the second electrode member 22 via the conductive terminal 31 to generate static electricity.

[0027] As can be seen from the background technology, the relative magnetic permeability of nickel alloy is 600, and the thermal expansion coefficient is greater than 6×10 -6 / K. In this embodiment, each of the conductive terminals 31 can be made of tungsten (W) or molybdenum (Mo). The relative magnetic permeability of tungsten (W) and molybdenum (Mo) is 1, which is much smaller than the relative magnetic permeability of nickel alloy. The thermal expansion coefficient of tungsten (W) is 2.5×10 -6 / K, the thermal expansion coefficient of molybdenum (Mo) is 3.0×10 -6 / K, which is less than the thermal expansion coefficient of nickel alloy and aluminum nitride. Therefore, the conductive terminals 31 used in this embodiment are less susceptible to thermal expansion and contraction than the carrier 1, making them less likely to crack during electrostatic chuck device processing. Specifically, each conductive terminal 31 in this embodiment is preferably made of molybdenum.

[0028] The electrostatic chuck device is suitable for use in a sputtering machine 5. The sputtering machine 5 includes a chamber 51, a magnet 52, and a target 53 disposed below the magnet 52. The target 53 is electrically connected to an AC power source 54. The electrostatic chuck device is disposed below the target 53. In this embodiment, the sputtering machine 5 can be used to perform physical vapor deposition (PVD) to deposit titanium nitride (TiN) on a substrate 6 located on the carrier 1.

[0029] A lifting device (not shown) is provided below the electrostatic suction cup device, and the lifting device has a lifting member (not shown) that can be lifted and lowered through the carrier 1. The substrate 6 can be grabbed by a robotic arm (not shown) to the top of the carrier 1. After the lifting member lifts the substrate 6, the robotic arm will move away, and the lifting member will be lowered to place the substrate 6 on the carrier 1. When the conductive terminal 31 is energized, the first electrode member 21 and the second electrode member 22 will generate static electricity, causing the substrate 6 to be adsorbed by the carrier 1. When the deposition process is completed, the air inlet channel 12, the air hole 14 and the air outlet channel 13 will be ventilated to release the adsorption of the substrate 6, so that the substrate 6 can be smoothly separated from the carrier 1.

[0030] See Figure 3 ,and Figure 4 During deposition, since the relative magnetic permeability of the conductive terminal 31 is relatively small, it is not easily magnetized by the magnet 52. When the titanium nitride ions 55 in the chamber 51 flow from the center toward the edge of the substrate 6 and pass over the top of the conductive terminal 31, they are less likely to be deviated by the magnetic field 56 generated by the conductive terminal 31, thereby reducing the degree to which the thin film 57 here is thicker on the side adjacent to the center of the substrate 6 and thinner on the side away from the center of the substrate 6.

[0031] See Figure 5 , the substrate 6 is divided into a first zone Z1, a second zone Z2, a third zone Z3, and a fourth zone Z4 in an annular shape from the center outward. In the deposition process, in order to ensure the uniformity of deposition, in addition to controlling the uniformity of the entire substrate 6, it is also necessary to control the uniformity of different areas on the substrate 6. Due to the position of the conductive terminal 31 in this embodiment (see Figure 3 ) correspond to the second zone Z2 and the fourth zone Z4 respectively, so the thickness range control of the second zone Z2 and the fourth zone Z4 is also very important.

[0032] Table 1 shows the average thickness, thickness range, and thickness uniformity of the films deposited on the substrate 6 for the conductive terminals 31 made of different materials. In the control example, the conductive terminals 31 were made of nickel alloy, while in the experimental example, the conductive terminals 31 were made of molybdenum.

[0033] As can be seen from Table 1, the uniformity of the deposited film as a whole is improved from 1.37% to 1.02%, and the thickness range of the second zone Z2 is from Improved to The improvement is 50.9%, and the thickness of the fourth zone Z4 ranges from Improved to The improvement is 44.3%. It can be seen that by replacing the material of the conductive terminal 31 with molybdenum, the thickness ranges of the second zone Z2 and the fourth zone Z4 are significantly improved. Furthermore, the maximum service life of the target 53 (expressed in kilowatt-hours (kWh)) is extended from 2700 kilowatt-hours (kWh) to 3000 kilowatt-hours (kWh), an increase of 11.1%. In addition to improving the uniformity of the deposited film thickness, this also extends the maintenance cycle of the machine, reduces maintenance material and labor costs, and increases production capacity.

[0034] Table 1

[0035]

[0036] In summary, the utility model is an electrostatic suction cup device that can improve the uniformity of the thickness of the deposited film. By selecting the terminal unit 3 with a relative magnetic permeability less than 50 to be set in the electrode unit 2, the terminal unit 3 can be prevented from being magnetized, so as to prevent the ions in the chamber 51 from being attracted by the terminal unit 3 during the deposition process, resulting in the film corresponding to the terminal unit 3 on the substrate 6 producing singular points of excessive thickness and excessive thinness, thereby reducing the thickness range to improve the uniformity of the deposited film on the substrate 6, so that the purpose of the utility model can indeed be achieved.

[0037] The above description is merely an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the claims and description of the present invention are still within the scope of the present invention.

Claims

1. An electrostatic chuck device capable of improving the uniformity of deposited film thickness, comprising a carrier, an electrode unit, and a terminal unit; characterized in that: The carrier includes a carrying surface, the electrode unit is arranged in the carrier and is used to generate static electricity, the terminal unit is arranged in the electrode unit and is located on the side of the electrode unit away from the carrying surface, the terminal unit is electrically connected to the electrode unit and has a relative magnetic permeability less than 50.

2. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 1, wherein: The terminal unit is made of molybdenum or tungsten.

3. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 1, wherein: The electrode unit includes a disc-shaped first electrode member and a second electrode member surrounding the first electrode member. The terminal unit includes two conductive terminals respectively disposed on the first electrode member and the second electrode member.

4. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 3, wherein: Each of the conductive terminals is made of molybdenum or tungsten.

5. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 1, wherein: The carrier is made of aluminum nitride, and the thermal expansion coefficient of the terminal unit is less than 4.5×10 -6 / K.

6. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 1, wherein: The invention also includes a heater arranged in the carrier.

7. The electrostatic chuck device capable of improving the uniformity of deposited film thickness according to claim 1, wherein: A plurality of air holes are formed on the carrying surface of the carrying platform.

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