Plasma processing device and processing method thereof

Abstract

The present invention discloses a plasma processing device, comprising: a reaction chamber; a base, which is arranged in the reaction chamber, and has a first gas channel in the base; a plurality of first gas supply sources, the plurality of first gas supply sources are connected to the first gas channel, and a valve is provided between any first gas supply source of the plurality of first gas supply sources and the first gas channel; a second gas supply device, which is arranged in the reaction chamber and is arranged opposite to the base. The present invention also discloses a wafer-free cleaning method.

Description

Technical Field

[0001] The invention relates to a plasma processing device and a processing method thereof, in particular to a lower electrode assembly in a plasma processing device and a wafer-free cleaning method. Background Art

[0002] Plasma processing devices usually process semiconductor substrates in a vacuum reaction chamber, such as etching, deposition, ion implantation, etc. A reaction gas containing an appropriate etchant source gas is introduced into the vacuum reaction chamber, and then radio frequency energy is input into the vacuum reaction chamber to activate the reaction gas to excite and maintain plasma, so as to etch the material layer on the substrate surface or deposit the material layer on the substrate surface, thereby processing the semiconductor substrate. The reaction chamber of the plasma processing device often produces a lot of pollution during the substrate processing process, such as metal pollution or polymer deposition. In order to remove these pollutants, it is often necessary to perform plasma cleaning after performing a certain number of substrate processing. However, in the process of cleaning the reaction chamber of the plasma processing device, unexpected secondary pollution will also be generated in the local area inside the chamber, thereby affecting the subsequent substrate manufacturing process. Summary of the invention

[0003] On the one hand, the present invention provides a plasma processing device, comprising: a reaction chamber; a base, which is arranged in the reaction chamber and has a first gas channel; a plurality of first gas supply sources, the plurality of first gas supply sources are connected to the first gas channel, and a valve is provided between any one of the plurality of first gas supply sources and the first gas channel; a second gas supply device, which is arranged in the reaction chamber and opposite to the base.

[0004] Optionally, the first gas channel is a cooling gas channel and / or a lift pin channel.

[0005] Optionally, the first gas supply source includes a helium gas supply source and a non-helium gas supply source. When processing a substrate, the first gas supply source is a helium gas supply source. When cleaning a reaction chamber, the first gas supply source is a non-helium gas supply source.

[0006] Optionally, the non-helium gas includes one or more of the following gases: oxygen, nitrogen, and argon.

[0007] Optionally, the plasma processing apparatus further includes a controller for controlling the opening and closing states of the plurality of valves.

[0008] Optionally, the base includes a base and an electrostatic chuck, and the first gas channel runs through the base and the electrostatic chuck.

[0009] Optionally, the second gas supply device is a gas shower head arranged at an upper part of the reaction chamber.

[0010] Optionally, the second gas supply device provides one or more of the following gases: fluoride gas, oxygen, and chlorine gas.

[0011] On the other hand, the present invention also provides a processing method for a plasma processing device, the plasma processing device comprising: a reaction chamber; a base, which is arranged in the reaction chamber, and the base has a first gas channel; a plurality of first gas supply sources, the plurality of first gas supply sources are connected to the first gas channel, and a valve is provided between any first gas supply source of the plurality of first gas supply sources and the first gas channel, and the first gas supply source comprises one or more of the following: a helium supply source, an oxygen supply source, a nitrogen supply source, and an argon supply source; a second gas supply device, which is arranged in the reaction chamber and is arranged opposite to the base;

[0012] The method comprises: introducing a cleaning gas into a reaction chamber through the second gas supply device; applying radio frequency energy to excite the cleaning gas into plasma to clean the interior of the reaction chamber; when the plasma cleans the interior of the reaction chamber, the first gas channel continuously provides a supply gas other than helium.

[0013] Optionally, the method includes closing a valve connecting a helium gas supply source and the first gas channel, and opening a valve connecting a non-helium gas supply source and the first gas channel.

[0014] Optionally, the gas pressure provided in the first gas channel is greater than the internal pressure of the reaction chamber when cleaning the plasma processing device.

[0015] Optionally, the gas pressure provided in the first gas channel is 10mT-10T.

[0016] Optionally, after the plasma processing device is cleaned, a reaction gas is introduced into the reaction chamber through the second gas supply device; radio frequency energy is applied to excite the reaction gas into plasma to etch the substrate on the base; during plasma etching, the first gas channel continuously supplies helium.

[0017] The present invention adds multiple gas supply sources connected to the gas channel in the base of the semiconductor processing device. The type and flow rate of the gas supplied to the gas channel can be controlled by opening and closing the valve, so that the supply gas can be flexibly switched according to demand during substrate processing and chamber cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A schematic structural diagram of a plasma processing device for processing a substrate according to an embodiment of the present invention is shown.

[0019] Figure 2 A schematic structural diagram of a plasma processing device when cleaning a device according to an embodiment of the present invention is shown.

[0020] Figure 3 A schematic structural diagram of a plasma processing device when cleaning a device according to another embodiment of the present invention is shown.

[0021] Figure 4 A flow chart showing a processing method of a plasma processing apparatus according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0022] To make the content of the present invention more clear and understandable, the content of the present invention is further described below in conjunction with the accompanying drawings of the specification. Of course, the present invention is not limited to this specific embodiment, and general replacements known to those skilled in the art are also covered within the protection scope of the present invention.

[0023] Typically, when performing waferless cleaning processes in semiconductor processing equipment, helium is flowed through the cooling gas holes of the electrostatic chuck to ensure that no polymer particles fall into these holes during the cleaning process. However, helium discharge can cause surface degradation of chamber kit parts. The injected helium atoms create voids and generate a foamy, porous layer on the surface of the parts. Helium swelling / blistering can occur on the surfaces of ceramics, silicon, silicon carbide, tungsten, molybdenum, and many other materials. Changing the surface properties will affect the conductivity, corrosion resistance, morphology, and other surface properties of the surface of the components in the chamber. This phenomenon can lead to two undesirable consequences for the chamber:

[0024] Shortened service life of chamber components due to surface degradation

[0025] · Particles due to foaming

[0026] Typically, swelling / blistering is observed on polished mirror surfaces rather than on rough machined surfaces. Therefore, mirror-polished chamber components (e.g., electrostatic chuck, gas showerhead, etc.) are at greater risk of shortened lifetime if helium is used for waferless cleaning.

[0027] The following description takes a capacitively coupled plasma etching device as an example. Those skilled in the art should understand that the present invention is not limited to this, but is also applicable to various plasma processing devices, such as an inductively coupled plasma etching device, an electron cyclotron resonance plasma etching device, a chemical vapor deposition device, etc.

[0028] Figure 1The schematic diagram of the structure of a plasma processing device for processing a substrate is shown, in particular, the plasma processing device is a plasma etching device 100. The plasma etching device 100 has a processing chamber, the processing chamber is substantially cylindrical, and the side wall 101 of the processing chamber is substantially vertical, and the processing chamber has a base 102 and a gas supply device arranged parallel to each other. In this embodiment, the gas supply device is a gas shower head 103. Usually, the area between the base 102 and the gas shower head 103 is a plasma processing area P, and the base 102 and the gas shower head 103 are fed with high-frequency energy as upper and lower electrodes to ignite and maintain plasma. A substrate W to be processed is placed above the base 102, and the substrate W can be a semiconductor substrate to be etched or processed or a glass flat plate to be processed into a flat panel display. The base 102 is used to clamp the substrate W. The reaction gas is input from the gas source 105 to the gas shower head 103 in the processing chamber. In one embodiment, the reaction gas may be one or more of fluoride gas, oxygen and chlorine. One or more RF power supplies 104 may be applied to the base 102 individually or simultaneously and separately to the base 102 and the gas shower head 103 to deliver RF power to these components, thereby generating a large electric field inside the processing chamber. Most of the electric field lines are contained in the processing area P between the base 102 and the gas shower head 103. This electric field accelerates a small amount of electrons present inside the processing chamber, causing them to collide with gas molecules of the input reaction gas. These collisions lead to ionization of the reaction gas and excitation of plasma, thereby generating plasma in the processing 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 neutral substances in the processed substrate, and substrate processing, such as etching, deposition, etc., is performed. An exhaust area is provided at a suitable position of the plasma etching chamber, and the exhaust area is connected to an external exhaust device (such as a vacuum pump 106) to extract the used reaction gas and byproduct gas from the chamber during the process. Among them, the plasma confinement ring 108 is used to confine the plasma in the processing area P. The chamber sidewall 101 is connected to the ground terminal.

[0029] like Figure 1As shown, in this embodiment, the plasma etching device 100 also includes a gas channel 107, and the gas channel 107 is arranged in the base 102. The length of the gas channel 107 is sufficient to pass through the entire base 102, and the gas channel 107 has a gas jet at one end close to the substrate W, and the gas jet can blow air toward the back of the substrate W placed thereon. In this embodiment, the gas channel 107 is a cooling gas channel in the base. In other embodiments, the gas channel 107 is a lifting pin hole channel in the base. In this embodiment, the base 102 includes a base made of metal, an electrostatic chuck made of a dielectric material, and a bonding layer that bonds the two. The gas channel 107 runs through the base, the electrostatic chuck, and the bonding layer. In other embodiments, the base 102 has other structures, such as only having a base made of metal and an electrostatic chuck, and the electrostatic chuck is bonded to the upper surface of the base by spraying technology. Alternatively, the base 102 only has a metal base that supports the substrate W. The gas channel 107 is connected to a plurality of gas supply sources for providing cooling gas or normal temperature gas to the gas channel 107. The gas supply source is also connected to a control device for controlling the plurality of gas supply sources to supply gas to the gas channel 107. In this embodiment, the plurality of gas supply sources are a helium supply source 201 and an oxygen supply source 202; the control device is a gas valve 211, 212. Specifically, valve 211 is disposed between the gas channel 107 and the helium supply source 201 for controlling the flow rate of helium. Valve 212 is disposed between the gas channel 107 and the oxygen supply source 202 for controlling the flow rate of oxygen. When the substrate is processed (etching or deposition, etc.), valve 211 is opened and valve 212 is closed so that the cooled helium is blown to the back of the substrate W through the gas channel 107 to continuously cool the substrate W being processed.

[0030] Figure 2 The schematic diagram of the structure of the plasma processing device during the cleaning of the device is shown. During the cleaning of the device, the substrate is removed for wafer-free cleaning operation. At this time, valve 212 is opened and valve 211 is closed to allow oxygen to flow into the gas channel 107. In one embodiment, the following cleaning process can be performed.

[0031] The gas source 105 is SF 6 , Cl 2 and O 2 The gas is supplied into the reaction chamber through the gas shower head 103. 6 , Cl 2 and O 2The flow rates of the three gases are 100-180s.ccm, 15-40s.ccm, and 15-60s.ccm, respectively. Then, 800W of radio frequency power is applied to the base 102 to excite the above gases into plasma and maintain the pressure of the reaction chamber at about 10-15mTorr for about 70 seconds.

[0032] The oxygen supply source 202 supplies oxygen to the gas channel 107 via the valve 212 and the oxygen pressure is slightly greater than the chamber pressure, for example, 20 mT, which can prevent particles generated when the plasma enters or cleans the chamber from falling into the gas channel 107 in the substrate 102 .

[0033] Figure 3 FIG. 1 shows a schematic diagram of the structure of a plasma processing device during cleaning of a device according to another embodiment. Figure 2 The difference is that it has four gas supply sources, namely helium supply source 201, oxygen supply source 202, nitrogen supply source 203 and argon supply source. They are connected to the gas channel 107 through a valve 211, 212, 213, 214 respectively. In one embodiment, when processing the substrate, the valve 211 is opened and the valves 212-214 are closed, so that the helium gas enters the back of the substrate through the gas channel 107; when cleaning the device, the valve 203 is opened, the valves 211, 212 and 214 are closed, so that the nitrogen gas enters the reaction chamber through the gas channel 107. The role of nitrogen is similar to that of oxygen. It can prevent swelling or bubbling on the surface of ceramics, silicon, silicon carbide, and other materials, and the helium pressure in the gas channel 107, which is slightly greater than the pressure of the reaction chamber, can prevent particles that fall off during cleaning from entering the gas channel 107. In another embodiment, argon gas can be introduced into the gas channel 107 (open valve 214 and close valves 211-213). In yet another embodiment, a mixed gas of two gases can be introduced into the gas channel 107. For example, by opening valves 212 and 213 and closing valves 211 and 214, a mixed gas of oxygen and nitrogen can be introduced.

[0034] The present invention also provides a method for treating a plasma treatment device. Figure 4As shown, in step S101, a cleaning gas is introduced into the reaction chamber through a gas supply source 105, and the cleaning gas includes one or more of fluoride gas, oxygen, and chlorine. In step S102, radio frequency energy is applied to excite the cleaning gas into plasma, thereby cleaning the interior of the reaction chamber. In S103, when the plasma cleans the interior of the reaction chamber, the gas channel 107 in the base 102 continues to provide a non-helium supply gas. For example, the supply gas is one or more of oxygen, nitrogen, or argon. The pressure of the supply gas is greater than the chamber pressure when the interior of the reaction chamber is cleaned. Optionally, after the cleaning is completed, a substrate etching operation is performed. At this time, the gas supply source 105 introduces a reaction gas into the reaction chamber, applies radio frequency energy to excite the reaction gas into plasma, and during etching, the gas channel 107 continues to provide helium.

[0035] Although the present invention has been disclosed as above with preferred embodiments, the embodiments are merely examples for the convenience of description and are not intended to limit the present invention. Those skilled in the art may make several changes and modifications without departing from the spirit and scope of the present invention. The scope of protection claimed by the present invention shall be based on the claims.

Claims

1. A processing method for a plasma processing device, the plasma processing device comprising: Reaction chamber; A base, which is arranged in the reaction chamber, and has a first gas channel; A plurality of first gas supply sources, the plurality of first gas supply sources are connected to the first gas channel, a valve is provided between any first gas supply source of the plurality of first gas supply sources and the first gas channel, the first gas supply source comprises one or more of the following: a helium supply source, an oxygen supply source, a nitrogen supply source, an argon supply source; A second gas supply device, which is disposed in the reaction chamber and opposite to the base; The method comprises: introducing a cleaning gas into the reaction chamber through the second gas supply device; Radio frequency energy is applied to excite the cleaning gas into plasma to clean the interior of the reaction chamber, so that the pressure of the reaction chamber is a first pressure; when the plasma cleans the interior of the reaction chamber, the first gas channel continuously provides a non-helium supply gas with a second pressure, and the second pressure is greater than the first pressure.

2. The processing method according to claim 1, characterized in that: The method includes closing a valve connecting a helium gas supply source and a first gas channel, and opening a valve connecting a non-helium gas supply source and the first gas channel.

3. The processing method according to claim 2, characterized in that: The gas pressure provided in the first gas channel is 10mT-10T.

4. The processing method according to claim 1, characterized in that: After the plasma processing device is cleaned, the reaction gas is introduced into the reaction chamber through the second gas supply device; radio frequency energy is applied to excite the reaction gas into plasma to etch the substrate on the base; during the plasma etching, the first gas channel continuously supplies helium.

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