TW202117799A - Plasma processor and method for preventing arc damage to confinement ring capable of preventing the confinement ring from being broken down by arc under a low frequency radio frequency electric field - Google Patents

Abstract

The present invention provides a plasma processor including a plasma reaction chamber. The bottom of the plasma reaction chamber is provided with a base for placing a wafer. A plasma confinement ring and a ground ring are arranged around the base. The outer ring of the plasma confinement ring is provided with a supporting part. A conductive layer is arranged between the support part and the ground ring for changing the original point contact manner between the support part and the ground ring to a surface contact manner to thereby increase an insulating contact area between the plasma confinement ring and the ground ring. The plasma confinement ring, the conductive layer, and the ground ring are integrated and fixedly connected by a plurality of screws, which reduces the distance between the plasma confinement ring and the area outside the original point contact of the ground ring, increases the capacitance between the plasma confinement ring and the ground ring, reduces the voltage difference between the plasma confinement ring and the ground ring, and prevents the confinement ring from being broken down by arc under a low frequency radio frequency electric field. The present invention also discloses a method for preventing arc damage to the confinement ring.

Description

Plasma processor and method for preventing arc damage of confinement ring

The invention relates to the technical field of plasma etching, in particular to a plasma processor and method for preventing arc damage to a confinement ring.

The plasma treatment process used in the manufacture of integrated circuits includes a plasma deposition process and a plasma etching process. In the process of processing the wafer through the plasma treatment process, the wafer is first fixedly placed in the plasma reaction chamber, and a patterned microelectronic layer is formed on the wafer. Then a radio frequency energy is emitted into the plasma reaction chamber through a radio frequency power transmitting device to form a radio frequency field; then various reaction gases (etching gas or deposition gas) are injected into the plasma reaction chamber, and the reaction gas injected under the action of the radio frequency field The top of the wafer is excited into a plasma state; finally, chemical reactions and/or physical interactions (such as etching, deposition, etc.) between the plasma and the wafer form various characteristic structures, and the volatile reactions formed in the chemical reactions generate The object is separated from the surface of the etched material and is drawn out of the cavity by the vacuum system.

In order to prevent the byproducts of the reaction from carrying plasma to the area outside the plasma processing area when being discharged from the reaction chamber and causing damage to the area, a plasma confinement ring is usually set between the wafer-bearing susceptor and the sidewall of the reaction chamber. A grounding ring is arranged under the ring to form a radio frequency loop between the plasma in the reaction chamber and the ground. Because the plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules, and free radicals. In order to protect the plasma confinement ring, the conventional technology covers the surface of the confinement ring by spraying a protective coating that is resistant to plasma corrosion. With the continuous development of the etching process, the frequency of the RF power applied to the susceptor continues to decrease. In the plasma reaction chamber, especially in the low-frequency plasma reaction chamber, when the voltage difference between the confinement ring and the ground ring When ΔU is too large, the insulating protective coating on the upper surface of the plasma confinement ring is easily broken down, and when the voltage difference between the confinement ring and the grounding ring ΔU is too large, arc discharge is prone to occur between the confinement ring and the grounding ring, resulting in plasma The processing equipment has potential safety hazards.

Therefore, there is a great need in the art for a plasma processing device that can adapt to low-frequency radio frequency power, which can prevent the confinement ring from being broken down by the arc on the premise of ensuring the etching stability and the symmetry of the etching result, and at the same time can prevent the confinement ring The heat is too high.

The purpose of the present invention is to provide a plasma processor that prevents arc damage to the confinement ring. When there is a low-frequency radio frequency electric field in the plasma reaction chamber, it can effectively prevent the confinement ring from arcing damage and can take into account the plasma etching symmetry. Sex. At the same time, the plasma processor of the present invention can also quickly and effectively take away the thermal energy generated by the confinement ring in the radio frequency electric field, and prevent the insulating material coated on the surface of the confinement ring from being thermally cracked.

In order to achieve the above objective, the present invention provides a plasma processor, including a plasma reaction chamber. The bottom of the plasma reaction chamber is provided with a susceptor for placing wafers, and a plasma confinement ring is arranged around the susceptor. A ground ring under the plasma confinement ring, the plasma confinement ring includes a plasma confinement area and a support portion supporting the plasma confinement area, and a conductive layer is arranged between the support portion and the ground ring, It is used to reduce the voltage difference between the plasma confinement ring and the ground ring.

The base is connected to a bias radio frequency power supply, and the radio frequency frequency output by the bias radio frequency power supply is less than or equal to 1 MHz.

Preferably, the conductive layer is a flexible conductive sheet.

The ground ring is in electrical contact with the conductive layer, and an insulating layer is provided in an area where the support portion and the conductive layer are in contact.

Preferably, the upper surface of the plasma confinement ring is coated with a protective coating resistant to plasma corrosion, and the lower surface is coated with the insulating layer formed of an insulating material.

Preferably, the conductive layer is made of aluminum-plated graphite.

A plurality of fixing devices are arranged between the supporting part and the ground ring, and the plasma confinement ring, the conductive layer and the ground ring are in close contact by the fixing devices.

Preferably, the plurality of fixing devices are evenly distributed between the supporting portion and the ground ring.

Preferably, the fixing device is a screw arranged inside the plasma confinement ring, and the screw does not come into contact with the plasma.

Preferably, the top of the screw is sprayed with a protective coating resistant to plasma corrosion.

An upper electrode is arranged in the plasma reaction chamber, the upper electrode is arranged opposite to the base, and the upper electrode is grounded.

The present invention also discloses a method for preventing arc damage of the confinement ring, which is realized by adopting a plasma processor that prevents arc damage of the confinement ring. The plasma processor includes a plasma reaction chamber. The bottom is provided with a susceptor for placing wafers, the susceptor is connected to a bias RF power supply with a radio frequency less than or equal to 1MHz, and a plasma confinement ring and a ground ring located below the plasma confinement ring are arranged around the susceptor The plasma confinement ring includes a plasma confinement area and a support portion supporting the plasma confinement area, and the support portion is disposed on an outer periphery of the plasma confinement ring. The method for preventing arc damage to a confinement ring includes steps: S1. Coating the outer surface of the plasma confinement ring with a protective coating resistant to plasma corrosion, and coating an insulating layer formed by insulating material on the lower surface of the plasma confinement ring; S2. A flexible conductive sheet is provided as a conductive layer between the support portion of the plasma confinement ring and the ground ring, and the original point contact method between the support portion and the ground ring is changed to a surface contact method, and the plasma confinement ring is added The insulation contact area with the grounding ring; S3. The plasma confinement ring, the conductive layer, and the grounding ring are integrally fixedly connected by a plurality of screws, which reduces the distance between the plasma confinement ring and the grounding ring outside the original point contact area, and realizes the increase of the plasma confinement ring and the grounding ring. The capacitance between the two reduces the voltage difference between the plasma confinement ring and the ground ring.

In the step S2, the screw is arranged inside the plasma confinement ring and does not extend from the plasma confinement ring; the top of the screw is sprayed with a plasma corrosion-resistant protective coating.

Compared with the conventional technology, the present invention has a simple structure and is easy to implement. Without additional calculations and measurements, it can be achieved that when there is a low-frequency radio frequency electric field in the plasma reaction chamber, the confinement ring can be effectively prevented from arcing damage, and the plasma etching symmetry can be taken into account. At the same time, the plasma processor of the present invention can also quickly and effectively take away the thermal energy generated by the plasma confinement ring in the radio frequency electric field, and prevent the insulating material coated on the surface of the plasma confinement ring from being thermally cracked.

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying 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 by those with ordinary knowledge in the technical field without making progressive work shall fall within the protection scope of the present invention.

The invention discloses a plasma processor for preventing arc damage to a confinement ring. FIG. 1 is a schematic diagram of the structure of the plasma processor 100 in the first embodiment of the present invention. The plasma processor 100 includes a plasma reaction chamber, and the plasma reaction chamber includes a substantially cylindrical reaction chamber side wall 170 made of a metal material. A susceptor 120 for placing the wafer 102 is provided at the bottom of the plasma reaction chamber, and an electrostatic chuck 115 for absorbing the wafer 102 is provided in the susceptor 120. A gas shower head 150 is arranged in the plasma reaction chamber, and the gas shower head 150 is connected to a gas supply device 10 for supplying reaction gas to the plasma reaction chamber during plasma etching. The gas shower head 150 is located above the base 120 and opposite to the base 120. Corresponding upper and lower electrodes are provided in the plasma reaction chamber for exciting the reaction gas to generate plasma 160, so that the plasma 160 (plasma) is filled in the plasma reaction chamber during the manufacturing process. An exhaust pump 125 is also provided under the plasma reaction chamber to discharge the reaction by-products into the plasma reaction chamber.

In the first embodiment of the present invention, the gas shower head 150 serves as the upper electrode of the plasma reaction chamber, and the upper electrode is grounded. The susceptor 120 serves as the bottom electrode of the plasma reaction chamber. The base 120 is connected to a source radio frequency power supply and a bias radio frequency power supply 145. The source radio frequency power can be selectively applied to the upper electrode or the lower electrode to generate a radio frequency electric field between the upper electrode and the lower electrode to dissociate the reaction gas into plasma 160; bias radio frequency power 145 is usually applied to the lower electrode for supporting the wafer 102. In order to generate an electric field that attracts the charged particles in the plasma to bombard the wafer, the plasma 160 acts on the wafer 102 to be processed to realize the processing of the wafer 102.

A plasma confinement ring 105 (FEIS ring) is provided around the susceptor 120. The plasma confinement ring 105 is located between the susceptor 120 and the side wall 170 of the reaction chamber in the plasma reaction chamber, and is used for expelling the reaction by-product gas from the reaction area. , The plasma 160 is confined in the plasma processing area, and the plasma 160 is prevented from overflowing from the plasma reaction chamber with the exhaust gas.

The plasma confinement ring 105 is made of aluminum, and the whole is anodized to form insulated anodized aluminum oxide. Then, yttrium oxide is coated on the upper surface of the plasma confinement ring 105, and a protective coating 1054 resistant to corrosion by the plasma 160 is formed on the upper surface of the plasma confinement ring 105. The anodized aluminum on the lower surface of the plasma confinement ring 105 forms an insulating layer 1055.

The plasma confinement ring 105 is provided with notches 1053 connecting the upper and lower surfaces of the plasma confinement ring 105. The notches 1053 form air flow channels penetrating the upper and lower surfaces of the plasma confinement ring 105. The size and depth of the openings of these air flow channels are The design can ensure that when the plasma 160 gas formed above the susceptor 120 flows through the plasma confinement ring 105, all the ions therein are extinguished and become a neutral gas flowing downward. The notch 1053 may be a dot structure, a ring structure, a radial structure, or a tooth structure. It can be understood that the notches 1053 on the plasma confinement ring 105 can adopt any structure and distribution shape, and only need to meet the restriction effect on the plasma 160 and the process requirements of the plasma reaction chamber.

In order to prevent the radio frequency electric field in the reaction chamber from spreading under the plasma confinement ring 105, the reaction gas that has returned to neutrality is ignited again to form a secondary plasma and contaminate the inner wall and exhaust pipe under the plasma reaction chamber. The large amount of electric charge accumulated on the plasma confinement ring 105 also needs to be directed to the conduction pipe of the ground terminal, so a ground ring 106 (MGR ring) is provided under the confinement ring 105. The ground ring 106 is made of a conductor and is electrically grounded, so that the radio frequency energy can be shielded above the ground ring 106 to avoid the generation of secondary plasma 160 and at the same time conduct away the accumulated charges on the plasma confinement ring 105. An insulating layer 1055 is formed by the insulating material coated on the lower surface of the plasma confinement ring 105, so that the contact mode between the ground ring 106 and the plasma confinement ring 105 is insulating contact. The plasma confinement ring 105 is at a floating potential, and the ground ring 106 is at a zero potential. The ground ring 106 and the plasma confinement ring 105 realize the transmission of radio frequency electric power through capacitive coupling (no direct current conduction).

As shown in Figures 1 and 2, in the first embodiment of the present invention, the plasma confinement ring 105 includes a plasma confinement region 1051, and the plasma confinement region 1051 is provided with a plurality of notches 1053 with concentric annular structures. . A support portion 1052 supporting the plasma confinement region 1051 is provided at the edge of the outer periphery of the plasma confinement region 1051. As an embodiment, the thickness of the support portion 1052 is greater than the plasma confinement area 1051, so that a gap is formed between the plasma confinement area 1051 and the ground ring 106. When the plasma confinement ring 105 is disposed on the ground ring 106, the support portion 1052 is in contact with the ground ring 106 and erects the plasma confinement area 1051 so that the plasma confinement area 1051 does not contact the ground ring 106.

A conductive layer 109 is also provided between the supporting portion 1052 of the plasma confinement ring 105 and the ground ring 106. The conductive layer 109 is a flexible conductive sheet, which is made of aluminum-plated graphite. As shown in FIG. 3, the conductive layer 109 is divided into three layers: an upper layer 1091, a middle layer 1092, a lower layer 1093, etc. The middle layer 1092 is made of aluminum, and the upper layer 1091 of the conductive layer 109 and the lower layer 1093 of the conductive layer 109 are all graphite Material. The upper layer 1091 of the conductive layer 109 is in contact with the support portion 1052 of the plasma confinement ring 105, which is an insulating contact; the lower layer 1093 of the conductive layer 109 is in contact with the ground ring 106, which is an electrical contact. The conductive layer 109 reduces the voltage difference between the plasma confinement ring 105 and the ground ring 106. The ground ring 106 is in electrical contact with the conductive layer 109, and the area where the support portion 1052 is in contact with the conductive layer 109 is in insulating contact.

A plurality of fixing devices are also arranged between the supporting portion 1052 and the ground ring 106, and close contact of the plasma confinement ring 105, the conductive layer 109 and the ground ring 106 is achieved through the fixing devices. Good heat conduction is achieved by pressing the graphite in the conductive layer 109 between the plasma confinement ring 105 and the ground ring 106. Preferably, the fixing device is a screw 108 arranged inside the plasma confinement ring 105. As shown in FIG. 4, the screws 108 are evenly distributed on the conductive layer 109 between the support portion 1052 and the ground ring 106. The screw 108 does not make contact with the plasma 160. The upper end of the screw 108 is located in the plasma confinement ring 105 and does not extend from the top of the plasma confinement ring 105; the lower end of the screw 108 is located in the ground ring 106 and does not extend from the ground ring 106. The top of the screw 108 is sprayed with insulating material to prevent the screw 108 from being bombarded by the plasma 160 in the plasma reaction chamber. The screw 108 is made of metal material, which has good thermal conductivity, conducts the heat generated by the plasma confinement ring 105 to the ground ring 106, and effectively prevents the coating on the upper surface of the plasma confinement ring 105 from expanding and cracking due to overheating.

Since it is impossible to make a completely flat surface by machining, the grounding ring 106 and the supporting part of the plasma confinement ring 105 have tiny irregularities on their respective surfaces. In the prior art, when the plasma confinement ring 105 is directly placed on the ground ring 106 , So that the plasma confinement ring 105 and the ground ring 106 are in point contact. The area outside the point contact between the ground ring 106 and the plasma confinement ring 105 has a certain separation distance. There is a voltage difference between the plasma confinement ring 105 and the ground ring 106. The smaller the angular frequency of the radio frequency generated by the radio frequency power transmitting device applied to the reaction chamber, the greater the voltage difference. When the voltage difference is greater than a certain value, an arc action occurs on the plasma confinement ring 105, causing arc damage to the plasma confinement ring 105. When the angular frequency of the radio frequency is less than 1MHz, especially less than or equal to 400KHz, the probability of arc damage to the plasma confinement ring 105 is high. On the other hand, as the separation distance between the ground ring 106 and the plasma confinement ring 105 is greater, the voltage difference between the plasma confinement ring 105 and the ground ring 106 is greater.

，其中Z為射頻電場中等離子體約束環105到接地環106的阻抗，ω是射頻的角頻率，C是等離子體約束環105與接地環106絕緣接觸面間的電容。如圖5所示，ΔU的值隨著ω的減小而增大，在ω的值較小，即等離子體反應腔內的射頻電場為低頻時（例如ω小於等於400KHz時），ΔU會出現陡增。當ΔU達到一個電壓值U₁ 時，等離子體約束環105就會發生電弧損傷，造成擊穿。在射頻的角頻率不變的情況下，通過增加

可以降低等離子體約束環105與接地環106之間的電壓差ΔU，防止等離子體約束環105發生電弧損傷。已知

，其中ɛ為等離子體約束環105與接地環106之間介質的介電常數，S為接地環106與等離子體約束環105的相對面積，d為接地環106與等離子體約束環105之間的距離，ɛ為固定值。接地環106與等離子體約束環105的相對面積S固定，通過減少接地環106與等離子體約束環105之間的距離d，可實現增大等離子體約束環105與接地環106絕緣接觸面間的電容C，達到減少接地環106與等離子體約束環105之間的電壓差ΔU的目的。In a plasma chamber with a low-frequency radio frequency electric field, the voltage difference between the ground ring 106 and the plasma confinement ring 105

, Where Z is the impedance from the plasma confinement ring 105 to the ground ring 106 in the radio frequency electric field, ω is the angular frequency of the radio frequency, and C is the capacitance between the insulating contact surface of the plasma confinement ring 105 and the ground ring 106. As shown in Figure 5, the value of ΔU increases as ω decreases. When the value of ω is small, that is, when the RF electric field in the plasma reaction chamber is low frequency (for example, when ω is less than or equal to 400KHz), ΔU will appear Sharp increase. When ΔU reaches a voltage value U ₁ , the plasma confinement ring 105 will be arc damaged, causing breakdown. Under the condition that the angular frequency of the radio frequency does not change, by increasing

The voltage difference ΔU between the plasma confinement ring 105 and the ground ring 106 can be reduced, and the arc damage of the plasma confinement ring 105 can be prevented. A known

, Where ɛ is the dielectric constant of the medium between the plasma confinement ring 105 and the ground ring 106, S is the relative area of the ground ring 106 and the plasma confinement ring 105, and d is the distance between the ground ring 106 and the plasma confinement ring 105 The distance, ɛ is a fixed value. The relative area S of the ground ring 106 and the plasma confinement ring 105 is fixed. By reducing the distance d between the ground ring 106 and the plasma confinement ring 105, the insulation contact surface between the plasma confinement ring 105 and the ground ring 106 can be increased. The capacitor C achieves the purpose of reducing the voltage difference ΔU between the ground ring 106 and the plasma confinement ring 105.

In the present invention, a conductive layer 109 is provided between the plasma confinement ring 105 and the ground ring 106. Since the conductive layer 109 is made of aluminum-plated graphite, the graphite material is relatively soft, and a small external force can cause the graphite to deform. . The screw 108 makes the ground ring 106, the conductive layer 109, and the plasma confinement ring 105 come into close contact, and the deformation produced by the graphite coated with the conductive layer 109 fills up the tiny unevenness between the ground ring 106 and the plasma confinement ring 105 to achieve The insulating point contact method between the support portion 1052 of the plasma confinement ring 105 and the ground ring 106 is an insulating surface contact method, which increases the insulating contact area between the plasma confinement ring 105 and the ground ring 106; further, through the insulation The surface contact method reduces the distance between the plasma confinement ring 105 and the ground ring 106 outside of the original point contact. In this way, the voltage difference of the area outside the original point contact is reduced, and the plasma confinement ring 105 is prevented from arcing damage. In addition, due to the good thermal conductivity of graphite, good heat conduction between the plasma confinement ring 105 and the ground ring 106 can be achieved.

During the etching process, when the gap between the plasma confinement ring 105 and the ground ring 106 is less than 0.2 mm, the ground capacitance of the plasma confinement ring 105 is as high as> 5 nf, and the ground ring 106 and the plasma confinement ring 105 are separated When the distance increases to 0.2mm or even higher, the capacitance to ground of the plasma confinement ring 105 drops to <2nf. When the distance between the ground ring 106 and the plasma confinement ring 105 is greater than 0.2 mm, the ground capacitance of the plasma confinement ring 105 will not be significantly affected. The transmission impedance between the ground ring 106 and the plasma confinement ring 105 is mainly determined by the capacitance between the insulating contact surfaces, and the impedance distribution of the plasma confinement ring 105 closest to the wafer 102 to be processed on the susceptor 120 will affect the susceptor. The radio frequency electric field distribution around 120 affects the plasma distribution and the uniformity of the etching effect. In order to ensure the uniformity of the plasma etching effect, the distance between the plasma confinement ring 105 and the ground ring 106 is usually set to be greater than 0.2 mm. Therefore, in order to prevent arc damage of the plasma confinement ring 105 and ensure uniformity of etching, preferably, the thickness of the conductive layer 109 is 0.2 mm.

The present invention also provides a method for preventing arc damage of the confinement ring 105, which is implemented by using a plasma processor 100 that prevents arc damage of the plasma confinement ring 105. The plasma processor 100 includes a plasma reaction chamber. The bottom of the plasma reaction chamber is provided with a susceptor 120 on which the wafer 102 is placed. The susceptor 120 is connected to a bias radio frequency power supply 145. A plasma confinement ring 105 and a plasma confinement ring are arranged around the susceptor 120. For the ground ring 106 below 105, a support portion 1052 is provided on the outer periphery of the plasma confinement ring 105, and the method for preventing arc damage of the plasma confinement ring 105 includes the steps:

S1. Coat the upper surface of the plasma confinement ring 105 with a protective coating resistant to plasma corrosion, and coat the lower surface of the plasma confinement ring 105 with an insulating material to form an insulating layer;

S2. A flexible conductive sheet is provided as the conductive layer 109 between the support portion 1052 of the plasma confinement ring 105 and the ground ring 106, and the original point contact method between the support portion 1052 and the ground ring 106 is changed to a surface contact method , Increase the insulating contact area between the plasma confinement ring 105 and the ground ring 106; preferably, the conductive layer 109 is made of aluminum-plated graphite, and the thickness of the conductive layer 109 is preferably 0.2 mm.

S3. The plasma confinement ring 105, the conductive layer 109, and the ground ring 106 are integrally fixedly connected by a plurality of screws 108, which reduces the distance between the plasma confinement ring 105 and the ground ring 106 outside the original point contact area, and realizes the increase of plasma The capacitance between the volume confinement ring 105 and the ground ring 106 reduces the voltage difference between the plasma confinement ring 105 and the ground ring 106, and conducts the heat generated by the plasma confinement ring 105 to the ground ring 106, effectively preventing The coating on the upper surface of the plasma confinement ring 105 expands and breaks due to overheating. The screw 108 is arranged inside the plasma confinement ring 105 and does not extend from the plasma confinement ring 105; the top of the screw 108 is sprayed with a plasma corrosion-resistant protective coating.

Compared with the conventional technology, the present invention has a simple structure and is easy to implement. Without additional calculations and measurements, it can be realized that when there is a low-frequency radio frequency electric field in the plasma reaction chamber, the plasma confinement ring 105 can be effectively prevented from arcing damage, and plasma etching symmetry can be taken into account. At the same time, the plasma processor 100 of the present invention can also quickly and effectively take away the thermal energy generated by the plasma confinement ring 105 in the radio frequency electric field, and prevent the insulating coating on the upper surface of the plasma confinement ring 105 from being thermally cracked.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person familiar with the technical field can easily think of various equivalents within the technical scope disclosed in the present invention. Modifications or replacements, these modifications or replacements should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the patent application.

100: Plasma processor 10: Gas supply device 102: Wafer 105: Plasma Confinement Ring 1051: Plasma confinement area 1052: Support 1053: Notch 1054: Protective coating 1055: insulating layer 106: Grounding ring 108: Screw 109: conductive layer 1091: upper floor 1092: middle layer 1093: lower 115: Electrostatic chuck 120: Pedestal 125: Exhaust pump 145: Bias RF power supply 150: Gas sprinkler 160: Plasma 170: reaction chamber side wall

In order to explain the technical solution of the present invention more clearly, the following will briefly introduce the accompanying drawings that need to be used in the description. Obviously, the accompanying drawings in the following description are an embodiment of the present invention, which is common in the technical field. For the knowledgeable person, under the premise of not paying progressive work, they can also obtain other drawings based on these drawings: FIG. 1 is a schematic structural diagram of a plasma processor in Embodiment 1 of the present invention; 2 is a schematic diagram of the connection relationship between the plasma confinement ring, the conductive layer, the ground ring, and the screw in the first embodiment of the present invention; 3 is a cross-sectional view of the conductive layer in the first embodiment of the present invention; 4 is a top view of the conductive layer and the screw in the first embodiment of the present invention; Figure 5 is a schematic diagram of the voltage between the confinement ring and the ground ring changing with the angular frequency of the radio frequency electric field.

100: Plasma processor

10: Gas supply device

102: Wafer

1051: Plasma confinement area

1052: Support

106: Grounding ring

108: Screw

109: conductive layer

115: Electrostatic chuck

120: Pedestal

125: Exhaust pump

145: Bias RF power supply

150: Gas sprinkler

160: Plasma

170: reaction chamber side wall

Claims (13)

A plasma processor includes a plasma reaction chamber. The bottom of the plasma reaction chamber is provided with a susceptor on which a wafer is placed, a plasma confinement ring is arranged around the susceptor and is located below the plasma confinement ring A ground ring in, wherein: the plasma confinement ring includes a plasma confinement area and a support portion supporting the plasma confinement area, and a conductive layer is provided between the support portion and the ground ring for reducing the plasma The voltage difference between the confinement ring and the ground ring. The plasma processor according to claim 1, wherein: the base is connected to a bias radio frequency power supply, and the radio frequency frequency output by the bias radio frequency power supply is less than or equal to 1 MHz. The plasma processor according to claim 1, wherein: the conductive layer is a flexible conductive sheet. The plasma processor according to claim 1, wherein: the ground ring is in electrical contact with the conductive layer, and an insulating layer is provided in a region where the support part is in contact with the conductive layer. The plasma processor according to claim 4, wherein: the upper surface of the plasma confinement ring is coated with a protective coating resistant to plasma corrosion, and the lower surface is coated with the insulating layer formed of an insulating material. The plasma processor according to claim 1, wherein: the conductive layer is made of aluminum-plated graphite. The plasma processor according to claim 1, wherein: a plurality of fixing devices are provided between the supporting portion and the ground ring, and the plasma confinement ring, the conductive layer, and the ground ring are realized by the plurality of fixing devices Close contact. The plasma processor according to claim 7, wherein the plurality of fixing devices are evenly distributed between the support part and the ground ring. The plasma processor according to claim 7, wherein: the plurality of fixing devices are screws arranged inside the plasma confinement ring, and the screws do not come into contact with the plasma. The plasma processor according to claim 9, wherein: the top of the screw is sprayed with a protective coating resistant to plasma corrosion. The plasma processor according to claim 1, wherein: an upper electrode is arranged in the plasma reaction chamber, the upper electrode is arranged opposite to the base, and the upper electrode is grounded. A method for preventing arc damage of a confinement ring is realized by using a plasma processor that prevents arc damage of the confinement ring. The plasma processor includes a plasma reaction chamber, and a crystal is placed on the bottom of the plasma reaction chamber. A circular base, the base is connected to a biased radio frequency power supply, a plasma confinement ring and a ground ring located below the plasma confinement ring are arranged around the base, and a support part is arranged on the outer periphery of the plasma confinement ring , Wherein, the method for preventing arc damage of the confinement ring includes the steps: S1. Coating a protective coating resistant to plasma corrosion on the upper surface of the plasma confinement ring, and coating an insulating material on the lower surface of the plasma confinement ring to form an insulating layer; S2. A flexible conductive sheet is arranged as a conductive layer between the support portion of the plasma confinement ring and the ground ring, and the original point contact method between the support portion and the ground ring is changed to a surface contact method, and The insulating contact area between the plasma confinement ring and the ground ring; S3. The plasma confinement ring, the conductive layer, and the ground ring are integrally fixedly connected by a plurality of screws, which reduces the distance between the plasma confinement ring and the area outside the original point contact of the ground ring, so as to increase the plasma confinement The capacitance between the ring and the ground ring reduces the voltage difference between the plasma confinement ring and the ground ring. The method for preventing arc damage to a confinement ring according to claim 12, wherein, in the step S2, the screw is arranged inside the plasma confinement ring and does not protrude from the plasma confinement ring; the top of the screw The protective coating that is resistant to plasma corrosion is sprayed.

Images