TWI747448B - Plasma processing device - Google Patents

Abstract

The invention discloses a plasma processing device, comprising a reaction chamber, the reaction chamber including a top wall, a side wall and a bottom wall; an upper electrode located in the reaction chamber and arranged at the top wall; located in the reaction chamber and opposite to the upper electrode The lower electrode provided; the ground ring located in the reaction chamber and surrounding the lower electrode; the conductive support provided around the lower electrode and connected between the ground ring and the side wall, the conductive support includes an inner ring contacting the ground ring and the side wall contacting The external ring and multiple impedance adjustable devices connected between the external ring and the internal ring. Connected between the ground ring and the side wall is a conductive support including multiple impedance adjustable devices. Different impedance adjustable devices can adjust the impedance of different areas of the ground ring to achieve the purpose of adjusting the impedance of the radio frequency loop; The impedance of the adjustment device is optimized to adjust the symmetry of the radio frequency distribution, so that the plasma processing device achieves the goal of high etching uniformity.

Description

Plasma processing device

The present invention relates to the technical field of plasma etching, and more specifically, to a plasma processing device.

In the manufacturing process of semiconductor devices, in order to form a predetermined pattern on the structural layer of the semiconductor wafer, most of the plasma processing equipment is used for production; specifically, a resist is used as a mask to be placed on the structural layer, and then the It is put into a plasma processing device, and the area not covered by the mask is etched with the plasma generated by the plasma processing device, and finally a structural layer with a preset pattern is completed. In the conventional plasma processing device, due to the asymmetry of the component structure (such as the substrate transmission channel) and other factors, it can lead to uneven etching, which ultimately has a great impact on product performance and yield.

In view of this, the present invention provides a plasma processing device, which effectively solves the problems existing in the conventional technology, so that the plasma processing device achieves the goal of high etching uniformity.

In order to achieve the above objectives, the technical solutions provided by the present invention are as follows:

A plasma processing device, including:

A reaction chamber, the reaction chamber including a top wall, a side wall, and a bottom wall;

An upper electrode located in the reaction chamber and arranged at the top wall;

A lower electrode located in the reaction chamber and arranged opposite to the upper electrode;

A ground ring located in the reaction chamber and arranged around the lower electrode;

And, a conductive support arranged around the lower electrode and connected between the ground ring and the side wall, wherein the conductive support includes an inner ring contacting the ground ring and an outer ring contacting the side wall And a plurality of adjustable impedance devices connected between the outer ring and the inner ring.

Optionally, the impedance adjustable device is a non-electrically controlled impedance adjustable device.

Optionally, the impedance adjustable device is a variable capacitance device, a variable resistance device or a variable inductance device.

Optionally, the impedance adjustable device is a pneumatic variable capacitive device.

Optionally, the pneumatic variable capacitance device includes:

A first electrode plate connected to the inner ring and a second electrode plate connected to the outer ring;

And, an air compression pipeline connected to the first electrode plate or the second electrode plate, and the air compression pipeline controls the movement of the connected electrode plate by air pressure to change the first electrode plate and the second electrode plate. The distance between the two plates.

Optionally, the plurality of adjustable impedance devices are arranged around the bottom electrode at equal intervals.

Optionally, the distance between any two adjacent adjustable impedance devices is different.

Optionally, in the multiple impedance adjustable devices:

In some of the impedance adjustable devices, the distance between two adjacent adjustable impedance devices is the same, and in other parts of the impedance adjustable devices, the distance between two adjacent adjustable impedance devices is different.

Optionally, an edge insulation ring is further provided between the lower electrode and the ground ring.

Optionally, the plasma processing device further includes a confinement ring arranged between the ground ring and the side wall, and the conductive support is located on a side of the confinement ring facing the bottom wall; wherein, the The confinement ring is used to neutralize the charged ions in the plasma at its area.

Compared with the conventional technology, the technical solution provided by the present invention has at least the following advantages:

The present invention provides a plasma processing device, including: a reaction chamber, the reaction chamber includes a top wall, a side wall, and a bottom wall; an upper electrode located in the reaction chamber and arranged at the top wall; A lower electrode located in the reaction chamber and opposite to the upper electrode; a ground ring located in the reaction chamber and arranged around the lower electrode; and, arranged around the lower electrode and connected to the ground ring The conductive support between the side wall and the side wall, wherein the conductive support includes an inner ring contacting the ground ring, an outer ring contacting the side wall, and a plurality of connecting rings connected between the outer ring and the inner ring. Impedance adjustable device. It can be seen from the foregoing that, in the technical solution provided by the present invention, a conductive support is connected between the ground ring surrounding the lower electrode and the side wall, and the conductive support includes a plurality of impedance adjustable devices, wherein different impedance adjustable devices can adjust the ground ring The impedance of different areas can be adjusted to achieve the purpose of adjusting the impedance of the RF loop; further, by optimizing the impedance adjustment of the different impedance adjustable devices, the adjustment of the symmetry of the RF distribution is realized, and finally the plasma processing device achieves high etching uniformity Purpose.

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained with ordinary knowledge in the technical field without making progressive work are within the protection scope of the present invention.

As mentioned in the background art, in the manufacturing process of semiconductor devices, in order to form a predetermined pattern on the structural layer of the semiconductor wafer, most of the plasma processing equipment is used for the production; specifically, the resist is used as a mask to set the pattern on the semiconductor wafer. The structure layer is then put into a plasma processing device, and the area not covered by the mask is etched with the plasma generated by the plasma processing device, and finally a structure layer with a preset pattern is completed. In the conventional plasma processing device, due to the asymmetry of the component structure (such as the substrate transmission channel) and other factors, it can lead to uneven etching, which ultimately has a great impact on product performance and yield.

Based on this, the embodiments of the present application provide a plasma processing device, which effectively solves the problems existing in the conventional technology, so that the plasma processing device achieves the goal of high etching uniformity. In order to achieve the foregoing objectives, the technical solutions provided by the embodiments of the present application are as follows, and the technical solutions provided by the embodiments of the present application will be described in detail with reference to FIGS. 1 to 3.

1 and FIG. 2, FIG. 1 is a schematic structural diagram of a plasma processing device provided by an embodiment of the application, and FIG. 2 is a schematic structural diagram of a conductive support provided by an embodiment of the application, wherein the plasma processing device includes :

The reaction chamber 100 includes a top wall 101, a side wall 102 and a bottom wall 103;

An upper electrode 200 located in the reaction chamber 100 and arranged at the top wall 101;

A lower electrode 300 located in the reaction chamber 100 and arranged opposite to the upper electrode 200;

A ground ring 400 located in the reaction chamber 100 and arranged around the bottom electrode 300;

And, a conductive support 500 arranged around the lower electrode 300 and connected between the ground ring 400 and the side wall 102, wherein the conductive support 500 includes an inner ring 500a that contacts the ground ring 400, The outer ring 500b contacting the side wall 102 and a plurality of impedance adjustable devices 500c connected between the outer ring 500a and the inner ring 500b.

Optionally, the plasma processing device provided by the embodiment of the present application further includes a confinement ring disposed between the ground ring and the side wall, and the conductive bracket is located at a point where the confinement ring faces the bottom wall. Side; wherein the confinement ring is used to neutralize the charged ions in the plasma at its region. Specifically in conjunction with FIG. 1, the plasma processing device provided by the embodiment of the present application further includes a confinement ring 600 disposed between the ground ring 400 and the side wall 102, and the conductive support 500 is located on the side of the confinement ring 600 facing the bottom wall 103. Among them, in the radio frequency current flow path of the plasma processing device provided by the embodiment of the present application, the high frequency power source provides radio frequency power to the lower electrode 300, and then the radio frequency current RF is conducted from the lower electrode 300 to the upper electrode 200, and then the upper electrode 200 again It is conducted to the top wall 101, and is conducted to the side wall 102, the conductive support 500 and the ground ring 400 along the top wall 101 to the ground terminal Gnd.

In an embodiment of the present application, by optimizing the size and aspect ratio of the gas flow channel of the confinement ring 600, the charged ions in the plasma above it are neutralized in the confinement ring, and only neutral gas components Go through the confinement ring to reach the conductive support 500 below. When the impedance adjustable device 500c in the conductive support is pneumatically adjusted, the impedance adjustable device may include an air cylinder, and the air cylinder is connected to an external air source through at least one air supply hose. Due to the existence of the upper confinement ring, the hose will not be corroded by plasma, so it can ensure the long-term stable operation of the entire impedance adjustable device.

Further, as shown in FIG. 1, as an example to avoid a discharge phenomenon between the bottom electrode 300 and the ground ring 400, in the plasma processing device provided by the embodiment of the present application, it is located between the bottom electrode 300 and the ground ring 400 An edge insulation ring 700 is also provided in the room.

It is understandable that a conductive support is connected between the ground ring surrounding the lower electrode and the side wall, and the conductive support includes a plurality of impedance adjustable devices. Among them, different impedance adjustable devices can adjust the impedance of different areas of the ground ring to achieve adjustment. The purpose of the impedance of the radio frequency loop; further, by optimizing the impedance adjustment of the different impedance adjustable devices, the adjustment of the symmetry of the radio frequency distribution is realized, and finally the plasma processing device achieves the goal of high etching uniformity.

It should be noted that during the working process of the plasma processing device provided in the embodiments of the present application, when the impedance of each impedance adjustable device is optimized and adjusted, the impedance needs to be optimized and adjusted according to the actual situation in the working process. By using the software system to optimize and adjust each impedance adjustable device, this application does not specifically limit the impedance adjustment trend of each impedance adjustable device.

The plasma processing device provided by the embodiment of the present application includes a reaction chamber enclosed by a top wall, a side wall, and a bottom wall. Various element structures are arranged in the reaction chamber and used for placing the substrate to be processed. The reaction cavity provided in this application may be cylindrical or other shapes, and this application is not specifically limited. The reaction chamber can be evacuated. Except for the air inlet, the exhaust port and the substrate inlet and outlet channels of the reaction chamber, the other parts of the reaction chamber are kept airtight and isolated from the outside during the processing process. The air inlet is connected with an external gas source and is used to continuously supply processing gas to the reaction chamber during the processing process. The exhaust port is connected with an external pump and is used to discharge the exhaust gas generated during the treatment process out of the reaction chamber, and is also used to control the air pressure in the reaction chamber.

The reaction chamber of the plasma processing device provided by the embodiment of the application includes an upper electrode and a lower electrode that are arranged oppositely. The upper electrode is set as a part of the gas shower head and can be used to guide gas into the reaction chamber; the lower electrode is provided with The electrostatic chuck, and the lower electrode is connected with a high-frequency power source, and the high-frequency power source provides radio frequency power for the lower electrode. Among them, the area between the upper electrode and the lower electrode is the treatment area, and the treatment area will generate high-frequency energy to ignite and maintain the plasma. The substrate to be processed is fixedly arranged on the electrostatic chuck below the processing area. During the working process of the high-frequency power source, the upper electrode and the lower electrode, most of the electric field is restricted in the processing area between the upper electrode and the lower electrode. The gas molecules of the reaction gas input from the shower head collide; these collisions cause the ionization of the reaction gas and the excitation of the plasma, thereby generating plasma in the reaction chamber; the neutral gas molecules of the reaction gas lose electrons when subjected to these strong electric fields , Leaving positively charged ions; the positively charged ions are accelerated toward the lower electrode, combined with the neutral substance in the substrate to be processed, and the substrate to be processed is processed by processes such as etching or deposition.

Further, in order to prevent the impedance adjustable device from affecting the electric field in the reaction chamber, the impedance adjustable device provided in the embodiment of the present application is a non-electrically controlled impedance adjustable device, so as to prevent the electric signal from affecting the electric field in the reaction cavity , To ensure that the adjustment difficulty is reduced.

And, the impedance adjustment described in the embodiment of the present application may be the adjustment of the resistance, the adjustment of the capacitance, or the adjustment of the inductance, which is not specifically limited in the present application. Wherein, the impedance adjustable device provided in this application is a variable capacitance device, a variable resistance device or a variable inductance device.

It should be noted that all the impedance adjustable devices provided in the embodiments of the present application may all be the same type of impedance adjustable devices; or, all the impedance adjustable devices include variable capacitance devices, variable resistance devices, and variable resistance devices. There are at least two types of inductance devices, which are not specifically limited in this application.

In an embodiment of the present application, the impedance adjustable device provided in the present application is a pneumatic variable capacitive device. Referring to FIG. 2, there is a schematic structural diagram of a pneumatic variable capacitive device provided in an embodiment of this application, wherein the pneumatic variable capacitive device provided in an embodiment of this application includes:

The first electrode plate 501 connected to the inner ring 500a and the second electrode plate 502 connected to the outer ring 500b;

And, the air compression pipe 503 connected to the first electrode plate 501 or the second electrode plate 502, the air compression pipe 503 controls the movement of the connected electrode plate by air pressure to change the first electrode plate The distance between 501 and the second electrode plate 502.

It is understandable that the air compression pipeline 503 provided by the embodiment of the present application includes a sealed pipeline 503a, and a gas baffle 503b and a spring element 503c located in the sealed pipeline 503a. The gas baffle 503b is connected to the electrode plate, and further, by Fill the sealed pipe 503a with gas, so that the gas baffle 503b compresses the spring element 503c, and the gas baffle 503b drives the electrode plate to move, so that the distance between the first electrode plate 501 and the second electrode plate 502 is reduced; and, By releasing the gas from the sealed pipe 503a, the spring element 503c is stretched to drive the gas baffle 503b to reset, and the gas baffle 503b drives the electrode plate to move, so that the distance between the first electrode plate 501 and the second electrode plate 502 is increased , And finally achieve the purpose of adjusting the distance between the first electrode plate 501 and the second electrode plate 502.

The embodiment of the present application does not impose specific restrictions on the manner in which the multiple impedance adjustable devices are distributed around the lower electrode, which requires specific design according to actual applications. Wherein, the plurality of adjustable impedance devices provided in the embodiments of the present application may be arranged around the bottom electrode at equal intervals. Or, the distance between any two adjacent adjustable impedance devices provided in the embodiment of the present application is different. Or, in the plurality of adjustable impedance devices:

In some of the impedance adjustable devices, the distance between two adjacent adjustable impedance devices is the same, and in other parts of the impedance adjustable devices, the distance between two adjacent adjustable impedance devices is different.

In any of the foregoing embodiments, the ground ring provided in this application may be a semiconductor material ground ring or a metal material ground ring, which is not specifically limited in this application.

An embodiment of the present application provides a plasma processing device, including: a reaction chamber, the reaction chamber including a top wall, a side wall, and a bottom wall; an upper electrode located in the reaction chamber and arranged at the top wall; A lower electrode located in the reaction chamber and opposite to the upper electrode; a ground ring located in the reaction chamber and arranged around the lower electrode; and, arranged around the lower electrode and connected to the The conductive support between the ground ring and the side wall, wherein the conductive support includes an inner ring contacting the ground ring, an outer ring contacting the side wall, and an outer ring connected between the outer ring and the inner ring Multiple impedance adjustable devices. It can be seen from the above content that, in the technical solution provided by the embodiments of the present application, a conductive support is connected between the ground ring surrounding the lower electrode and the side wall. The conductive support includes a plurality of adjustable impedance devices, wherein the different impedance adjustable devices can be adjusted. The impedance of different areas of the ground ring can be adjusted to achieve the purpose of adjusting the impedance of the RF loop; further, by optimizing the impedance adjustment of the different impedance adjustable devices, the adjustment of the symmetry of the RF distribution is realized, and finally the plasma processing device can achieve etching uniformity High purpose.

The above description of the disclosed embodiments enables those with ordinary knowledge in the technical field to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined in this document can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this document, but should conform to the widest scope consistent with the principles and novel features disclosed in this document.

100: reaction chamber 101: top wall 102: side wall 103: bottom wall 200: Upper electrode 300: Lower electrode 400: Grounding ring 500: Conductive bracket 500a: Inner ring 500b: External ring 500c: Impedance adjustable device 501: first plate 502: second plate 503: Air compression line 503a: Sealed pipe 503b: Gas baffle 503c: spring element 600: Restraint ring 700: Edge insulation ring

In order to more clearly describe the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are merely It is an embodiment of the present invention. For those with ordinary knowledge in the technical field, other schemas can be obtained according to the provided schemas without making progressive labor. FIG. 1 is a schematic structural diagram of a plasma processing device provided by an embodiment of the application; FIG. 2 is a schematic structural diagram of a conductive support provided by an embodiment of the application; Fig. 3 is a schematic structural diagram of a pneumatic variable capacitive device provided by an embodiment of the application.

100: reaction chamber

101: top wall

102: side wall

103: bottom wall

200: Upper electrode

300: Lower electrode

400: Grounding ring

500: Conductive bracket

500a: Inner ring

500c: Impedance adjustable device

600: Restraint ring

700: Edge insulation ring

Claims (10)

A plasma processing device, which includes: A reaction chamber, the reaction chamber including a top wall, a side wall and a bottom wall; An upper electrode located in the reaction chamber and arranged at the top wall; A lower electrode located in the reaction chamber and arranged opposite to the upper electrode; A grounding ring located in the reaction chamber and surrounding the bottom electrode; And, a conductive support arranged around the bottom electrode and connected between the ground ring and the side wall, wherein the conductive support includes an inner ring contacting the ground ring, an outer ring contacting the side wall, and an outer ring connected to the side wall. A plurality of adjustable impedance devices between the external ring and the internal ring. The plasma processing apparatus according to claim 1, wherein the adjustable impedance device is a non-electrically controlled impedance adjustable device. The plasma processing device according to claim 1 or 2, wherein the adjustable impedance device is a variable capacitance device, a variable resistance device or a variable inductance device. The plasma processing apparatus according to claim 3, wherein the impedance adjustable device is a pneumatic variable capacitance device. The plasma processing device according to claim 4, wherein the pneumatic variable capacitance device includes: A first plate connected to the inner ring and a second plate connected to the outer ring; And, an air compression pipeline connected to the first electrode plate or the second electrode plate, and the air compression pipeline controls the movement of the connected electrode plate by air pressure to change the first electrode plate and the second electrode The spacing between the boards. The plasma processing device according to claim 1, wherein the plurality of adjustable impedance devices are arranged around the bottom electrode at equal intervals. The plasma processing apparatus according to claim 1, wherein the distance between any two adjacent adjustable impedance devices in the plurality of adjustable impedance devices is different. The plasma processing device according to claim 1, wherein, in the plurality of adjustable impedance devices: The distance between two adjacent adjustable impedance devices in a part of the plurality of adjustable impedance devices is the same, and the distance between two adjacent adjustable impedance devices in the other part of the plurality of adjustable impedance devices is different. The plasma processing device according to claim 1, wherein an edge insulation ring is further provided between the lower electrode and the ground ring. The plasma processing device according to claim 1, wherein the plasma processing device further includes a confinement ring arranged between the ground ring and the side wall, and the conductive bracket is located on a side of the confinement ring facing the bottom wall; Among them, the confinement ring is used to electrically neutralize the charged ions in the plasma at its area.

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