TWI827991B - Lower electrode element and plasma processing apparatus including lower electrode element - Google Patents

Abstract

The invention provides a lower electrode element and a plasma processing device including the lower electrode element, wherein the lower electrode element includes: a base; and an electrostatic chuck located on the base for adsorbing a substrate to be processed. , the material of the lower electrode element is ceramic non-metallic material; a gas delivery pipe runs through the base and is used to transport gas; a gas diffusion chamber, a gas inlet and a gas outlet are located in the electrostatic chuck and come from The gas in the gas delivery pipe enters the gas diffusion chamber through the gas inlet, is diffused through the gas diffusion chamber, and then output to the back side of the substrate to be processed through the gas outlet. The plasma treatment device can prevent arc discharge.

Description

Lower electrode element and plasma processing apparatus including lower electrode element

The present invention relates to the field of semiconductors, and in particular, to a lower electrode element and a plasma processing device including the lower electrode element.

Among the various processes of semiconductor device manufacturing, plasma processing is a key process in which the substrate to be processed is placed in a plasma processing device and processed into a designed pattern. In a typical plasma treatment process, the process gas forms plasma under radio frequency (Radio Frequency, RF) excitation. After passing through the electric field (capacitive coupling or inductive coupling) between the upper electrode and the lower electrode, these plasmas undergo physical bombardment and chemical reaction with the surface of the substrate to be processed, thereby processing the substrate to be processed.

In situations where plasma is used to process the substrate to be processed on an electrostatic chuck, a higher temperature of the substrate to be processed and a higher radio frequency power are often required. Under high temperature and high power, it is easy to cause the gas in the pores to be destroyed. Wearing will cause arcing. Severe arcing will cause arc damage to the substrate to be processed and the electrostatic chuck, and even cause permanent damage to the electrostatic chuck.

Therefore, there is an urgent need for a plasma treatment device to reduce arc damage.

The technical problem solved by the present invention is to provide a lower electrode element and a plasma processing device including the lower electrode element to prevent arc discharge.

In order to solve the above technical problems, the present invention provides a lower electrode element, including: a base; an electrostatic chuck, located on the base, used to absorb the substrate to be processed, and the material of the electrostatic chuck is a ceramic non-metallic material; A gas transport pipeline runs through the base and is used to transport gas; a gas diffusion chamber, a gas inlet and a gas outlet are provided in the electrostatic chuck, and the gas from the gas transport pipeline enters the gas diffusion chamber through the gas inlet. cavity, and then diffused through the gas diffusion cavity and then output to the back side of the substrate to be processed through the gas outlet.

Preferably, the electrostatic chuck includes a plurality of concentric gas areas, each gas area is provided with the gas diffusion chamber, a gas inlet and a gas outlet, and each gas area corresponds to a gas delivery pipe.

Preferably, the base includes a platform part and a step part located around the platform part; the electrostatic chuck is located on the platform part.

Preferably, the step portion includes at least one edge diffusion area, and the lower electrode element further includes: an edge air inlet, an edge diffusion cavity, and an edge air outlet, located in the edge diffusion area, and the edge air inlet The mouth and the edge air outlet are respectively located below and above the edge diffusion cavity, and the edge air inlet and edge air outlet edge diffusion cavity are connected and penetrate the step portion.

Preferably, the number of gas diffusion regions is two or more.

Preferably, the material of the electrostatic chuck includes: insulating material or semiconductor material; the material of the electrostatic chuck includes: aluminum oxide or aluminum nitride.

Preferably, the gas diffusion chamber is an annular cavity with a notch; it also includes: electrodes located between the notches and in the electrostatic chuck inside and outside the annular cavity; a DC power supply electrically connected to the electrodes. To generate electrostatic attraction to attract the substrate to be processed.

Preferably, the gas transported by the gas transport pipeline is helium.

Preferably, it also includes: a coolant channel located in the base for transporting coolant; and a bonding layer located between the electrostatic chuck and the base.

Preferably, it also includes: a gas source; a plurality of gas branches, the two ends of the gas branches are respectively connected to the pressure controller and the gas source, and the gas branches are connected to the gas delivery pipeline or the edge air inlet.

Preferably, the number of gas branches is equal to the sum of the number of gas delivery pipes and edge air inlets, and one gas branch is connected to one gas delivery pipe or edge air inlet.

Preferably, the number of gas branches is less than the sum of the number of gas delivery pipes and edge air inlets. There is a gap between multiple gas delivery pipes, or between multiple edge air inlets, or between an edge delivery pipe and an edge. A gas branch is shared between the air inlets.

Correspondingly, the present invention also provides a plasma processing device, including: a reaction chamber; and the above-mentioned lower electrode element is located at the bottom of the reaction chamber.

Preferably, the plasma processing device is a capacitively coupled plasma processing device, further comprising: a mounting substrate located at the top of the reaction chamber; a gas shower head located below the mounting substrate and connected to the lower electrode element Relatively arranged; a radio frequency power source is electrically connected to the gas shower head or the base; a bias radio frequency power source is electrically connected to the base.

Preferably, the plasma processing device is an inductively coupled plasma processing device, further comprising: an insulating window located at the top of the reaction chamber; an inductor coil located above the insulating window; a radio frequency power source, and the The inductor coil is electrically connected; the bias radio frequency power source is electrically connected to the base.

Compared with the conventional technology, the technical solutions of the embodiments of the present invention have the following beneficial effects: In the lower electrode element provided by the technical solution of the present invention, the electrostatic chuck is provided with a gas diffusion chamber, a gas inlet and a gas outlet. The gas inlet is used to receive gas from the gas delivery pipe in the base below the electrostatic chuck. The gas enters the gas diffusion chamber through the gas inlet, diffuses in the gas diffusion chamber, and is discharged to the back of the substrate to be processed through the gas outlet. Since the electrostatic chuck is made of ceramic non-metal material, even if arc discharge occurs in the electrostatic chuck, it will not generate a large current, so arc damage will not be caused and the electrostatic chuck will not be permanently damaged.

Furthermore, the electrostatic chuck includes a plurality of concentric gas areas. Each gas area is provided with a gas diffusion chamber, a gas inlet and a gas outlet. The gas inlet is connected to the gas delivery pipe and can be adjusted to enter the gas delivery channel. The gas pressure in the pipeline can control the temperature of the surface of the substrate to be processed in the corresponding area, thereby making the temperature of different areas of the substrate to be processed adjustable.

As mentioned in the prior art, the existing lower electrode element is prone to arc discharge. Therefore, the present invention is dedicated to providing a lower electrode element and a plasma processing device including the lower electrode element, which can prevent arc discharge.

Detailed description below:

Figure 1 is a schematic structural diagram of a plasma processing device according to the present invention.

Please refer to Figure 1. The plasma processing device 1 includes: a reaction chamber 10; a lower electrode element 11, located at the bottom of the reaction chamber 10, for carrying the substrate W to be processed; and a mounting substrate 12, located in the reaction chamber. The top of 10; the gas shower head 13 is located below the mounting substrate 12 and is opposite to the lower electrode element 11.

In this embodiment, the plasma processing device is a capacitively coupled plasma etching device (CCP). The plasma processing device further includes: a gas supply device 15 connected to the gas shower head 13 . The gas supply device 15 is used to transport reaction gas into the gas shower head 13; the radio frequency power source 14 connected to the gas shower head 13 or the lower electrode element 11, the corresponding gas shower head 13 or the lower electrode element 11 is grounded, the radio frequency power The radio frequency signal generated by the source 14 converts the reaction gas into plasma through the capacitance formed by the gas shower head 13 and the lower electrode element 11. The plasma contains a large number of electrons, ions, excited atoms, molecules, free radicals and other active particles. , the active particles can undergo various physical and chemical reactions with the surface of the substrate to be treated, causing the morphology of the surface of the substrate to change, that is, completing the etching process. Furthermore, the plasma processing device further includes: a biased radio frequency power source (not shown in the figure), connected to the lower electrode element 11, for controlling the bombardment direction of charged particles in the plasma.

In other embodiments, the plasma processing device is an inductively coupled plasma etching device (ICP), and the plasma processing device further includes: a gas delivery device for delivering reaction gas into the reaction chamber; radio frequency power The source is connected to the inductor coil; the bias RF power source applies the bias RF voltage to the lower electrode element through the RF matching network to control the bombardment direction of charged particles in the plasma; a vacuum pump is also provided below the reaction chamber. It is used to discharge the reaction by-products from the reaction chamber and maintain the vacuum environment of the reaction chamber; a gas delivery device is provided on the side wall of the reaction chamber close to the end of the insulating window, or a gas delivery device can be set in the center area of the insulating window. The gas delivery device is used When the reaction gas is injected into the reaction chamber, the radio frequency power of the radio frequency power source drives the inductor coil to generate a strong high-frequency alternating magnetic field, so that the low-pressure reaction gas in the reaction chamber is ionized to generate plasma.

Please refer to Figure 1. The lower electrode element 11 also includes: an electrode 16, which is provided in the electrostatic chuck 119; a direct current power supply DC, electrically connected to the electrode 16, for generating electrostatic attraction to adsorb the material to be processed. Substrate W.

The lower electrode element 11 is described in detail below:

FIG. 2 is a top view of the lower electrode element 11 in the plasma processing device of FIG. 1; FIG. 3 is a partial enlarged view of the lower electrode element in FIG. 1.

Please refer to Figures 2 and 3. The lower electrode element 11 includes: a base 117; an electrostatic chuck 119, located on the base 117, for adsorbing the substrate W to be processed. The material of the electrostatic chuck 119 is ceramic non-metal. Materials; gas delivery pipes (113A and 113B), running through the base 117, for transporting gas; gas diffusion chamber 111, gas inlet 112 and gas outlet 110, located in the electrostatic chuck 119, from the The gas in the gas delivery pipes (113A and 113B) enters the gas diffusion chamber 111 through the gas inlet 112, is diffused by the gas diffusion chamber 111, and then output to the surface of the substrate W to be processed through the gas outlet 110.

In this embodiment, the gas diffusion chamber 111 is an annular cavity with a notch; it also includes: electrodes 16 (see Figure 1 ), which are provided between the notches and in the electrostatic chuck 119 inside and outside the annular cavity.

In this embodiment, the lower electrode element 11 also includes: a lifting hole 150 (see Figure 2) for accommodating a lifting pin (not shown in the figure), and the lifting pin moves up and down in the lifting hole 150. , to lift up or put down the substrate W to be processed, thereby realizing the picking and placing of the substrate W to be processed. The lower electrode element 11 also includes a sealing band 120 for dividing gas areas to accommodate helium in different gas areas.

The material of the electrostatic chuck 119 is a ceramic non-metal material. The material of the electrostatic chuck 119 includes: insulating material or semiconductor material; the material of the electrostatic chuck includes: aluminum oxide or aluminum nitride. Since the gas diffusion chamber 111 is disposed in the electrostatic chuck 119, and the electrostatic chuck 119 is made of ceramic non-metallic material, even if arc discharge occurs in the electrostatic chuck, it will not cause a large arc discharge. current, so it will not cause arc damage and permanently damage the electrostatic chuck.

In this embodiment, the base 117 includes a platform portion and a step portion located around the platform portion. Process kits are placed above the step portion; the electrostatic chuck 119 is located on the platform portion. , the electrostatic chuck 119 includes a plurality of concentric gas regions A. Here, two gas regions A are used for schematic illustration. In fact, the number of gas regions A can also be other numbers, and each gas region A can be The gas area A is provided with the gas diffusion chamber 111, a gas inlet 112 and a gas outlet 110. Each gas area A corresponds to a gas delivery pipe (113A, 113B), and the gas delivery pipe (113A, 113B) runs through the platform portion. .

In other embodiments, the base 117 is a plate material without a step.

Since the plurality of gas areas A are concentric, and there are gas delivery pipes (113A, 113B) in each gas area A to transport helium gas into the gas diffusion chamber 111 through the gas inlet 112, the helium gas diffuses in the gas diffusion chamber 111 Finally, the gas flows out through the gas outlet 110 and reaches the back side of the substrate W to be processed to control the temperature of different areas of the substrate W to be processed. The gas pressure of the helium gas in each gas area A can be controlled to achieve better temperature adjustability between different areas of the substrate W to be processed, which is beneficial to improving the consistency of surface etching of the substrate W to be processed.

In this embodiment, two gas regions A are used as an example for description. The gas delivery pipe 113A is used to deliver helium gas to the gas inlet 112 of the inner ring, and the gas delivery pipe 113B is used to deliver helium gas to the gas inlet 112 of the outer ring. Inlet 112 delivers helium gas.

In this embodiment, the step portion includes at least one edge diffusion area. Here, the number of edge diffusion areas is one as an example. In fact, the number of edge diffusion areas is not limited and can be many. Piece. The lower electrode element 11 also includes: an edge air inlet 114, an edge diffusion cavity 115 and an edge air outlet 116, which are located in the edge diffusion area. The edge air inlet 114 and edge air outlet 116 are respectively located in the edge diffusion area. Below and above the edge diffusion cavity 115, the edge air inlet 114 and the edge air outlet 116 are connected with the edge diffusion cavity 115 and penetrate the step portion. Helium gas is delivered into the edge diffusion chamber 115 through the edge air inlet 114, and the helium gas is blown to the component above the step portion through the edge gas outlet 116 to control the temperature on the component.

In this embodiment, the lower electrode element 11 also includes: a cooling liquid channel 130 (see FIG. 3 ), located in the base 117 and used to transport cooling liquid. The cooling liquid flows in the cooling liquid channel 130 and takes away the heat of the base 117 during the flow process to achieve temperature control of the base 117 .

In addition, a bonding layer 118 is provided between the electrostatic chuck 119 and the base 117 . The bonding layer 118 is used to improve the bonding force between the electrostatic chuck 119 and the base 117 .

The gas supply system that delivers helium gas to the gas delivery pipes (113A, 113B) and the edge gas inlet 114 is described in detail below:

Figure 4 is a schematic structural diagram of an air supply system of the present invention.

Please refer to Figure 4. The gas supply system includes: a gas source 140; a plurality of gas branches 145. Both ends of the gas branch 145 are respectively connected to the pressure controller (141, 142 and 143) and the gas source 140. The gas branch 145 It is connected with the gas delivery pipes (113A, 113B) or the edge gas inlet 114 of the reaction chamber 10.

In this embodiment, there are two gas regions A and one edge diffusion region as an example for schematic explanation. Each gas region A is transported through a gas delivery pipe (113A or 113B). Helium, one of the edge diffusion zones delivers helium through an edge inlet 114 .

In other embodiments, the number of the gas regions and the edge diffusion regions is other values, but the number of the gas branches is equal to the sum of the number of gas delivery pipes and edge air inlets. One gas A branch connects a gas delivery pipe or an edge air inlet, and no two gas delivery pipes, two edge air inlets, or a gas delivery pipe and an edge air inlet share a gas branch.

In this embodiment, the number of gas branches 145 is three, among which two gas branches 145 are connected to the gas delivery pipes (113A and 113B) respectively, and one gas branch 145 is connected to the edge air inlet 114. Each gas branch 145 is provided with a pressure controller (141 or 142 or 143). By adjusting the pressure of the pressure controller (141 or 142 or 143) on each gas branch 145, the entry into each gas delivery pipeline is controlled. (113A, 113B) or the amount of helium in the edge air inlet 114, thereby controlling the temperature conditions of different areas of the substrate W to be processed, so as to improve the temperature adjustability of the substrate W to be processed.

Figure 5 is a schematic structural diagram of another air supply system of the present invention.

Please refer to Figure 5. The gas supply system includes: a gas source 240; a plurality of gas branches 245. Both ends of the gas branches 245 are connected to the pressure controller (241 or 242) and the gas source 240 respectively. The gas branches 245 are connected to the reaction The gas delivery pipes (113A, 113B) or edge air inlets 114 of the chamber 10 are connected.

In this embodiment, there are still two gas areas A and one edge diffusion area as an example for schematic explanation. There are two gas branches 245 , and one gas branch 245 is connected to a pressure Controller (241 or 242), the other end of one pressure controller 241 is connected to a gas delivery pipeline (113A) through an input line 246, and the other end of the other pressure controller 242 is also connected to an input line 246, but The input line 246 is divided into two input branches (246a and 246b). One of the input branches 246b is provided with a control valve 247. The two input branches (246a and 246b) are connected to a gas delivery pipe (113B) and an edge respectively. The air inlet 114 is connected. By adjusting the pressure of the pressure controller 241, the helium gas pressure in the gas delivery pipes (113A, 113B) connected thereto is controlled, thereby controlling the temperature of the corresponding area of the substrate W to be processed. By adjusting the pressure of another pressure controller 242, the helium flow rate on the input line 246 connected to it is controlled, and then by adjusting the control valve 247, the amount of helium entering the two input branches 246a and 246b is adjusted, thereby Adjust the amount of helium in the connected gas delivery pipes (113A, 113B) and the edge air inlet 114, thereby controlling the corresponding temperature of the substrate W to be processed to increase the surface temperature of the substrate W to be processed of adjustability.

In other embodiments, there are two gas regions, one edge diffusion zone, and two gas branches. One of the gas branches is connected to a pressure controller, and the other end of one of the pressure controllers is An input line is connected to an edge air inlet, and the other end of another pressure controller is also connected to an input line, except that the input line is divided into 2 input branches, and the 2 input branches are respectively connected to the 2 gas delivery Pipeline connection.

Or, in other embodiments, the number of gas branches is less than the sum of the number of gas delivery pipes and edge air inlets, between multiple gas delivery pipes, or between multiple edge air inlets, or between edge air inlets. A gas branch is shared between the delivery pipe and the edge air inlet.

In this embodiment, since the number of the control valves is smaller than the number of the gas branches, which is smaller than the sum of the number of gas delivery pipes and edge air inlets, the design of the gas supply system is simplified and limited space can be saved. And more efficient use of resources, and help reduce space footprint and reduce costs.

Figure 6 is a schematic structural diagram of another air supply system of the present invention.

Please refer to Figure 6. The gas supply system includes: a gas source 340; a gas branch 345. Both ends of the gas branch 345 are connected to the pressure controller 341 and the gas source 340 respectively. The gas branch 345 is connected to the gas in the reaction chamber 10. The delivery pipes (113A, 113B) or edge air inlets 114 are connected.

In this embodiment, there are still two gas areas A and one edge diffusion area as an example for schematic explanation. There are one gas branches 345, and one gas branch 345 is connected to a pressure Controller 341, the other end of one of the pressure controllers 341 is connected to an input line 346, but the input line 346 is divided into three input branches (346a, 346b and 346c), and the three input branches (346a, 346b and 346c) are respectively connected with the gas delivery pipelines (113A, 113B) and the edge air inlet 114, and two of the input branches (346b and 346c) are respectively provided with control valves (347a and 347b). By respectively adjusting the control valves (347a and 347b), the pressure of the helium gas blown to different areas of the substrate W to be processed is adjustable, thereby improving the adjustability of the temperature of different areas of the substrate W to be processed.

In this embodiment, since the number of the control valves is only one, the air supply system is simpler, can save limited space and use resources more effectively, and is conducive to reducing space and floor space, and reducing costs. .

In fact, for the above gas supply system, the number of gas sources 140 is not limited to one, the number of gas sources 140 can be multiple, and the gas branch 145 can also be more branches, which is not limited here.

Although the present invention is disclosed as above, the present invention is not limited thereto. Any person with ordinary knowledge in the technical field to which this invention belongs will not depart from this. Various changes and modifications can be made within the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be based on the scope defined by the patent application scope.

1:Plasma treatment device 10:Reaction chamber 11: Lower electrode component 110:Gas outlet 111:Gas diffusion chamber 112:Gas inlet 113A, 113B: Gas transmission pipeline 114: Edge air inlet 115: Edge diffusion cavity 116: Edge air outlet 117:Pedestal 118: Bonding layer 119:Electrostatic chuck 12:Install the base plate 120:Sealing tape 13:Gas sprinkler head 130: Coolant channel 14: RF power source 140, 240, 340: Air source 141, 142, 143, 241, 242, 341: Pressure controller 145, 245, 345: Gas branch 15:Gas supply device 150: Lift hole 16:Electrode 246, 346: Input line 246a, 246b, 346a, 346b, 346c: input branch 247, 347a, 347b: Control valve A: Gas area DC: direct current power supply W: substrate

Figure 1 is a schematic structural diagram of a plasma treatment device according to the present invention; Figure 2 is a top view of the lower electrode element in the plasma processing device of Figure 1; Figure 3 is a partial enlarged view of the lower electrode element in Figure 1; Figure 4 is a schematic structural diagram of an air supply system of the present invention; Figure 5 is a schematic structural diagram of another air supply system of the present invention; Figure 6 is a schematic structural diagram of yet another air supply system of the present invention.

1:Plasma treatment device

10:Reaction chamber

11: Lower electrode component

12:Install the base plate

13:Gas sprinkler head

14: RF power source

15:Gas supply device

16:Electrode

DC: direct current power supply

W: substrate

Claims (15)

A lower electrode component for a plasma processing device, which includes: a base; An electrostatic chuck, located on the base, is used to adsorb a substrate to be processed. The material of the electrostatic chuck is ceramic non-metallic material; a gas delivery pipe that runs through the base and is used to deliver gas; and A gas diffusion chamber, a gas inlet and a gas outlet are provided in the electrostatic chuck. The gas from the gas delivery pipe enters the gas diffusion chamber through the gas inlet, and then diffuses through the gas diffusion chamber and passes through the gas diffusion chamber. The gas outlet is output to the back side of the substrate to be processed. The lower electrode element according to claim 1, wherein the electrostatic chuck includes a plurality of concentric gas regions, each gas region is provided with the gas diffusion chamber, the gas inlet and the gas outlet, and each gas region Corresponds to one gas delivery pipeline. The lower electrode element according to claim 2, wherein the base includes a platform portion and a step portion located around the platform portion; and the electrostatic chuck is located on the platform portion. The lower electrode element according to claim 3, wherein the step portion includes at least one edge diffusion area, and the lower electrode element further includes: an edge air inlet, an edge diffusion cavity and an edge air outlet, located on each of the edge diffusion areas. In the edge diffusion area, the edge air inlet and the edge air outlet are respectively located below and above the edge diffusion cavity. The edge air inlet and the edge air outlet are connected with the edge diffusion cavity and penetrate the step portion. The lower electrode element according to claim 2, wherein the number of the gas regions is two or more. The lower electrode element according to claim 1, wherein the material of the electrostatic chuck includes: insulating material or semiconductor material; the material of the electrostatic chuck includes: aluminum oxide or aluminum nitride. The lower electrode element as claimed in claim 1, wherein the gas diffusion cavity is an annular cavity with a gap; the lower electrode element further includes: an electrode disposed between the gap and the annular cavity inside and outside the Inside the electrostatic chuck; a DC power supply is electrically connected to the electrode and used to generate electrostatic attraction to adsorb the substrate to be processed. The lower electrode element according to claim 1, wherein the gas transported by the gas transport pipeline is helium. The lower electrode component according to claim 1, further comprising: a cooling liquid channel provided in the base for transporting cooling liquid; a bonding layer provided between the electrostatic chuck and the base . The lower electrode element as claimed in claim 4, further comprising: a gas source; a plurality of gas branches, both ends of which are respectively connected to a pressure controller and the gas source, and the gas branches are connected to the gas delivery pipeline Or the edge air inlet is connected. The lower electrode element according to claim 10, wherein the number of the gas branches is equal to the sum of the number of the gas delivery pipes and the edge air inlets, and one of the gas branches is connected to one of the gas delivery pipes or the edge. Air intake. The lower electrode element according to claim 10, wherein the number of the gas branches is less than the sum of the number of the gas delivery pipes and the edge air inlets, between a plurality of the gas delivery pipes, or between a plurality of the edges The gas branch is shared between the air inlets, or between the edge conveying pipe and the edge air inlet. A plasma processing device including a lower electrode element, which includes: a reaction chamber; and The lower electrode element as described in any one of claims 1 to 12 is provided at the bottom of the reaction chamber. The plasma processing device including a lower electrode element as claimed in claim 13, wherein the plasma processing device is a capacitively coupled plasma processing device and further includes: a mounting substrate located on the top of the reaction chamber; a gas spray A head is located below the mounting substrate and is opposite to the lower electrode element; a radio frequency power source is electrically connected to the gas shower head or the base; a bias radio frequency power source is electrically connected to the base. The plasma processing device including a lower electrode element as described in claim 13, wherein the plasma processing device is an inductively coupled plasma processing device, and further includes: an insulating window located on the top of the reaction chamber; an inductor coil, Located above the insulation window; a radio frequency power source is electrically connected to the inductor coil; a bias radio frequency power source is electrically connected to the base.