CN115547799A - Plasma confinement ring, plasma processing apparatus and method of processing semiconductor - Google Patents
Plasma confinement ring, plasma processing apparatus and method of processing semiconductor Download PDFInfo
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- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
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- H01L21/3065—Plasma etching; Reactive-ion etching
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Abstract
The invention discloses a plasma confinement ring, plasma processing equipment and a method for processing a semiconductor, wherein the plasma confinement ring is arranged in a reaction cavity of the plasma processing equipment and comprises a circular side wall and a gas channel wall fixedly connected with the circular side wall; the annular side wall is arranged on a support ring, and the support ring is fixed with the side wall of the reaction cavity; thermal insulation slits provided in the annular side wall for slowing down the heat transfer from the wall of the gas channel to the side wall of the reaction chamber. The present invention allows the temperature of the plasma confinement ring to reach a preset temperature and be maintained, thereby achieving the purpose of preventing polymer deposition.
Description
Technical Field
The present invention relates to the field of semiconductor processing equipment, and more particularly, to a plasma confinement ring, a plasma processing apparatus, and a method for processing a semiconductor.
Background
When a semiconductor substrate is etched by using the plasma processing equipment, a plasma confinement ring needs to be arranged around the base, namely on an air exhaust path, so that plasma in the reaction space reaches electric neutrality before being exhausted to the bottom of the reaction chamber.
During the process, the pumped gas in the reaction chamber transfers heat to the sidewall of the gas channel of the plasma confinement ring to maintain the plasma confinement ring at a certain temperature, but the temperature of the plasma confinement ring is reduced due to the heat loss, so that byproducts generated in the reaction process are easily deposited on the sidewall of the gas channel. Especially in the etching process with high aspect ratio, the etching time is long, and the polymer accumulation speed is high, so that the gas channel is narrowed, the gas flowing speed is influenced, even part of the gas channel is blocked, and the etching on the surface of the substrate is uneven.
Disclosure of Invention
The invention aims to provide a plasma confinement ring, plasma processing equipment and a method for processing a semiconductor, which are used for solving the problems that an air pumping channel (a gas channel or an annular channel) is narrowed, the air pumping speed is influenced, and even the air pumping channel is blocked, and further the high aspect ratio etching process is influenced due to the lower temperature of the plasma confinement ring.
In order to solve the above problems, the present invention is realized by the following technical solutions:
a plasma confinement ring disposed within a reaction chamber of a plasma processing apparatus, the plasma confinement ring comprising an annular sidewall and a gas passage wall fixedly connected to the annular sidewall; the annular lateral wall is placed on the support ring, the support ring with the lateral wall of reaction chamber is fixed, still includes: and the heat insulation gap is arranged in the annular side wall and is used for slowing down the heat transfer from the wall of the gas channel to the side wall of the reaction chamber.
Optionally, the heat insulation gap includes: a slit a extending axially along the annular sidewall.
Optionally, the slits a are at least two slit groups, where two slits a have openings on the surface of the annular sidewall, and the directions of the two openings are opposite.
Alternatively, the gap a is located close to the gas passage wall.
Optionally, the heat insulation gap includes: a slit B extending radially along the annular sidewall.
Optionally, the slits B are at least two slit groups, where two slits B have openings on the surface of the annular sidewall, and the directions of the two openings are opposite.
Optionally, the gap B is disposed adjacent to the support ring.
Optionally, the width of the heat insulation gap is 0.2 mm-2 mm.
Optionally, the annular side wall includes an annular inner side wall and an annular outer side wall, the gas channel wall is located between the annular inner side wall and the annular outer side wall, and the heat insulation gap is located in the annular inner side wall and/or the annular outer side wall.
Optionally, the gas channel wall is composed of a plurality of concentrically arranged nested rings with different diameters, the nested rings are fixedly connected with the annular side wall through spokes at the lower part of the nested rings, and the joints of the spokes and the annular inner side wall and/or the annular outer side wall are provided with gaps C extending along the axial direction of the annular side wall.
Optionally, the width of the gap C is 0.5mm to 1mm.
Alternatively, the gas passage wall is comprised of a torus having a plurality of through holes.
Optionally, the heat insulation gap is annular, and a gap C along the axial direction of the annular side wall is arranged at the joint of the annular body and the annular inner side wall and/or the annular outer side wall.
Optionally, the heat insulation gap is circular.
Optionally, the support ring is a conductor, and the plasma confinement ring is grounded, and a slit extending along the radial direction of the support ring is provided on the support ring.
Optionally, the heat insulation gap is filled with a heat insulation material.
Optionally, the annular inner side wall, the annular outer side wall and the gas channel wall are integrally designed.
Further, the present invention also discloses a plasma processing apparatus comprising: the device comprises a reaction cavity, a substrate and a substrate support, wherein a base for bearing the substrate is arranged in the reaction cavity;
the gas injection device is used for conveying reaction gas into the reaction cavity;
the plasma confinement ring of any one of the above claims, circumferentially disposed about the pedestal.
Further, a method for processing a semiconductor by using the plasma processing apparatus is also disclosed, which comprises:
conveying reaction gas into the reaction cavity;
ionizing the reaction gas into plasma and etching the semiconductor substrate on the pedestal in the reaction cavity;
during etching, the gas channel walls are maintained at a temperature at which no etching polymer is deposited by slowing down the transfer of heat from the gas channel walls to the side walls of the reaction chamber through the thermal isolation gaps.
Compared with the prior art, the invention has at least one of the following advantages:
according to the plasma confinement ring provided by the invention, the heat transfer from the gas channel to the side wall of the reaction chamber is slowed down by arranging the heat insulation gap on the annular outer side wall and/or the annular inner side wall. Namely, the arrangement of the heat insulation gap is equivalent to adding a large-area heat insulation layer on the annular outer side wall and/or the annular inner side wall. Thus, for example, the thermal isolation gap is arranged on the annular outer side wall, and the heat of the plasma confinement ring can only flow to the side wall of the reaction chamber through the residual thin wall on the inner side of the annular outer side wall, so that the heat transmission from the plasma confinement ring to the side wall is greatly reduced, and the gas channel can maintain the temperature and prevent the polymer from depositing.
The heat insulation gaps are annular, namely the first gap to the fourth gap are annular, due to the skin effect of radio frequency current, when the radio frequency is higher than 100kHz, the distribution depth of the radio frequency current on the plasma confinement ring (made of aluminum or aluminum alloy) is less than 0.3mm, and the radio frequency current only flows through the inner surface and the bottom surface of the side wall of the plasma confinement ring. Therefore, the thermal isolation gap provided by the invention does not affect the RF current path from the plasma confinement ring to the MGR (support ring), and thus does not affect the plasma distribution in the reaction chamber.
The third gap is more inside than the fourth gap, so that the heat transfer path from the gas channel of the plasma confinement ring to the side wall of the reaction chamber is longer, the temperature of the plasma confinement ring is easier to reach the preset temperature and maintain, and the aim of preventing polymer deposition is fulfilled.
Drawings
FIG. 1 is a schematic cross-sectional view of a plasma confinement ring according to an embodiment of the invention;
FIG. 2 is a schematic cross-sectional view of a plasma confinement ring according to another embodiment of the invention;
FIG. 3 is a schematic cross-sectional view of a plasma confinement ring according to another embodiment of the invention;
FIG. 4 is a schematic diagram illustrating a top view of a plasma confinement ring according to another embodiment of the invention;
FIG. 5 is a schematic diagram of a main structure of a plasma processing apparatus according to an embodiment of the present invention;
fig. 6 is a schematic cross-sectional view of a plasma confinement ring according to another embodiment of the invention. Detailed Description
A plasma confinement ring, a plasma processing apparatus and a method for processing a semiconductor according to the present invention will be described in further detail with reference to the accompanying drawings and detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise scale for the purpose of facilitating and distinctly aiding in the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, etc. shown in the drawings and attached to the description are only for understanding and reading the disclosure of the present disclosure, and are not for limiting the scope of the present disclosure, so they do not have the essential meaning in the art, and any modifications of the structures, changes of the ratio relationships, or adjustments of the sizes, should fall within the scope of the present disclosure without affecting the efficacy and the achievable purpose of the present disclosure.
Example one
As shown in fig. 1, the present embodiment provides a plasma confinement ring, which is disposed in a reaction chamber 100 of a plasma processing apparatus, a sidewall of the reaction chamber 100 is provided with an extending step 101 extending inward and radially, the plasma confinement ring includes a circular sidewall and a gas channel wall 300, the circular sidewall can be specifically divided into a circular outer sidewall 302 and a circular inner sidewall 303; the gas passage wall 300 is disposed inboard between the annular outer side wall 302 and the annular inner side wall 303; the annular outer side wall 302 is placed on the support ring 400, the support ring 400 is placed above the extending step 101, in other embodiments, the support ring can be connected with the side wall of the reaction chamber by other means besides the extending step, such as screw fixation; the plasma confinement ring further comprises: thermal insulation gaps, which are provided on the annular outer sidewall 302 and/or the annular inner sidewall 303, are used to slow down the heat transfer from the gas channel wall 300 to the sidewall of the reaction chamber 100.
Therefore, the plasma confinement ring provided by the embodiment slows down the heat transfer from the gas channel to the side wall of the reaction chamber by providing the thermal insulation gap on the annular outer side wall and/or the annular inner side wall, wherein the annular outer side wall is located between the gas channel and the side wall of the reaction chamber and serves as an intermediate structure for heat transfer, the thermal insulation gap is provided on the annular outer side wall, the gas exhaust path is not affected, the structure with a specific shape is easy to machine, and the heat can be significantly controlled on one side of the gas channel due to the intermediate position for heat transfer. Namely, the arrangement of the heat insulation gap is equivalent to adding a large-area heat insulation layer on the annular outer side wall and/or the annular inner side wall. Thus, for example, when the thermal insulation gap is arranged on the annular outer side wall, the heat of the plasma confinement ring can only flow to the side wall of the reaction chamber through the residual thin wall on the inner side of the annular outer side wall, so that the heat transmission from the plasma confinement ring to the side wall is greatly reduced, the temperature of the gas channel can be kept, and the polymer deposition is prevented.
With continued reference to fig. 1, the insulation gap includes a gap B extending along the radial direction of the annular outer sidewall, and the number of the gaps B may be one, for example, the first gap 3011 is formed in the annular outer sidewall 302, and in other embodiments, the number of the gaps B may also be plural, the first gap 3011 is disposed close to the support ring 400, i.e., close to the lower surface of the annular sidewall relative to the upper surface of the annular sidewall, so that the annular sidewall is divided into an upper portion and a lower portion by the first gap, the upper portion has a larger thermal mass relative to the lower portion, the first gap reduces the speed of heat loss from above the annular sidewall, i.e., reduces the temperature change of the upper portion, and the first gap 3011 extends along the radial direction of the annular outer sidewall 302, the first gap 3011 may be open towards the sidewall of the reaction chamber as shown in fig. 1, or open away from the sidewall of the reaction chamber, or be of a closed structure, the first gap 3011 allows the upper portion and the lower portion of the annular outer sidewall 302 to have a smaller contact area with the lower portion, and the lower portion to maintain the stability of the support, and reduce the temperature of the upper portion and reduce the temperature of the lower portion by a balance.
As shown in fig. 1, the present embodiment further includes: a plurality of horizontal spokes 301 and a plurality of nested rings, wherein a plurality of horizontal spokes 301 are arranged between the annular outer side wall 302 and the annular inner side wall 303 at intervals in the circumferential direction, a plurality of nested rings are arranged on the horizontal spokes 301 and are connected with the annular outer side wall 302 and the annular inner side wall 303 through the horizontal spokes 301, and the interval gaps between two adjacent nested rings form the gas channel; a gap C3010 is provided at the connection between each horizontal spoke 301 and the annular outer side wall 302 and/or the connection between each horizontal spoke 301 and the annular inner side wall 303, and the gap C3010 is used for slowing down the heat transfer from the gas channel to the side wall of the reaction chamber.
The slits C3010 may be opened downwards or upwards, such as in the embodiment of fig. 1, which is opened downwards, so that the heat of the gas channel wall 300 is transferred to the annular outer side wall 302 only through a small portion of the horizontal spokes 301 connecting to the annular outer side wall 302, and the cross-sectional area of heat transfer is reduced, i.e. the slits C3010 slow down the heat transfer from the gas channel wall 300 to the annular outer side wall 302, i.e. reduce the heat transfer to the side wall of the reaction chamber 100.
In this embodiment, the first slot 3011 has a ring shape. The plurality of nested rings are equally spaced and concentrically arranged.
According to this embodiment, in order to improve the heat insulation effect of the heat insulation gap and improve the mechanical properties of the horizontal spoke 301 and the annular outer side wall 302, the first gap 3011 and the gap C3010 may be filled with a heat insulation material. Such as, but not limited to, teflon (Teflon).
With continued reference to fig. 1, the support ring 400 may be a conductor, and the annular outer sidewall 302 and the annular inner sidewall 303 are disposed above the support ring 400, concentrically with the annular outer sidewall 302 and the annular inner sidewall 303, and between the annular outer sidewall 302 and the extension step 101, so as to ground the annular outer sidewall 302 and thus the plasma confinement ring. In this embodiment, the width of the gap C is 0.5mm to 1mm, and the width of the thermal insulation gap is 0.2mm to 2mm, so as to maintain smooth rf transmission and ensure that the mechanical strength of the gap C and the width of the gap in the thermal insulation gap are too small, the two sides of the gap are too close to each other, which weakens the effect of reducing heat transmission, and the flow field transmission of the rf is damaged due to too large width.
Example two
As shown in fig. 2, the difference between the present embodiment and the first embodiment is that the insulation gap is a gap a extending along the axial direction of the annular outer sidewall, and the number of the insulation gaps may be one and has no opening structure, for example, a second gap 3012 is formed in the annular outer sidewall 302, the second gap 3012 is disposed near the inner sidewall of the annular outer sidewall 302, and the second gap 3012 extends along the axial direction of the annular outer sidewall 302. The heat of the gas channel wall 300 flows up and down along the inner annular outer side wall 302 divided by the second slit 3012, and the annular outer side wall is divided into an inner portion and an outer portion by the second slit, and since the cross-sectional area of the inner portion of the annular outer side wall 302 is smaller than that of the outer portion, the heat is transmitted slowly there, so that the second slit reduces the rate at which the heat is lost from the inner portion to the outer portion of the annular outer side wall, and has the effect of maintaining the gas channel wall 300 at a high temperature.
According to the present embodiment, in order to improve the heat insulation effect of the heat insulation gap and improve the mechanical properties of the horizontal spokes 301 and the annular outer side wall 302, the second gap 3012 and the gap C3010 may be filled with heat insulation materials. Such as, but not limited to, teflon (Teflon).
Therefore, a narrow and high slit is longitudinally cut along the inner side of the annular outer side wall of the plasma confinement ring, so that the heat flow of the plasma confinement ring can only be transmitted downwards along the narrow thin wall, and the heat loss of the plasma confinement ring can be greatly reduced.
EXAMPLE III
As shown in fig. 3, the present embodiment is different from the first embodiment in that the number of the slits a may be multiple, and the present embodiment has an opening structure, for example, a third slit 3103 and a fourth slit 3104 are formed in the annular outer side wall 302, the third slit 3103 and the fourth slit 3104 are concentrically arranged, the third slit 3103 and the fourth slit 3104 are arranged near the inner side wall of the annular outer side wall 302, an opening of the third slit 3103 is close to the support ring 400, and an opening of the fourth slit 3104 is far from the support ring 400; the third slit 3103 extends in the axial direction of the annular outer side wall 302 in a direction away from the support ring 400, and the fourth slit 3104 extends in the axial direction of the annular outer side wall 302 in a direction close to the support ring 400.
According to this embodiment, in order to improve the heat insulation effect of the heat insulation gap and improve the mechanical property of the annular outer side wall 302, the third gap 3103 and the fourth gap 3104 may be filled with a heat insulation material. Such as, but not limited to, teflon (Teflon).
In the present embodiment, the third slit 3103 is disposed closer to the inner sidewall of the annular outer sidewall 302 than the fourth slit 3104.
The third slit provided by this embodiment is located more inside than the fourth slit, the opening of the third slit 3103 is downward, and the opening of the fourth slit 3104 is upward, so that the heat transfer path from the gas channel of the plasma confinement ring to the side wall of the reaction chamber is longer, thereby more easily reducing the heat loss of the plasma confinement ring, achieving a better heat insulation effect, further improving the temperature amplitude and distribution uniformity of the plasma confinement ring, and making the temperature of the plasma confinement ring reach a preset temperature and be maintained, thereby achieving the purpose of preventing polymer deposition.
It is understood that, in some other embodiments, for example, when the thermal insulation gap is disposed in the annular inner side wall 303, the specific structure of the thermal insulation gap is similar to that of the thermal insulation gap described in the first to third embodiments, and is not described herein again.
In addition, in some other embodiments, the plasma confinement ring may be disposed such that the annular outer sidewall is in contact with the support ring, the thermal isolation gap is disposed in the annular outer sidewall, and the annular inner sidewall is not in contact with the support ring; therefore, a gap exists between the annular inner side wall and the support ring, the effect of reducing the heat transfer cross-sectional area can be achieved, and the purpose of reducing the heat loss of the plasma confinement ring is further achieved.
Or the annular inner side wall is in contact with the support ring, the heat insulation gap is arranged in the annular inner side wall, and the annular outer side wall is not in contact with the support ring; therefore, a gap exists between the annular outer side wall and the support ring, the effect of reducing the heat transfer cross section area can be achieved, and the purpose of reducing the heat loss of the plasma confinement ring is further achieved.
Alternatively, both the annular outer side wall and the annular inner side wall are in contact with the support ring, and the heat insulation gap is provided in both the annular outer side wall and the annular inner side wall, as shown in fig. 6.
When the annular inner side wall and the annular outer side wall are both in contact with the support ring, the heat insulation gap is arranged, so that the purpose of reducing the heat loss of the plasma confinement ring is achieved.
In some other embodiments, as shown in fig. 4, the gas passage wall is a torus 304, and the torus 304 is disposed between the annular outer sidewall 302 and the annular inner sidewall 303, and the three are concentrically disposed; alternatively, the torus 304 is integrally provided with the annular outer side wall 302 and the annular inner side wall 303; a plurality of through holes are distributed on the torus 304 at intervals (the through holes may be distributed in a single row at intervals along the circumference of the torus 304, or may be distributed in multiple rows at intervals along the circumference of the torus 304), and each through hole forms the gas channel wall 300.
In some embodiments, a fifth slit is further included, which is disposed inside the support ring 400.
The fifth gap arranged inside the support ring 400 can also achieve the effect of reducing the heat transfer cross-sectional area, thereby achieving the purpose of reducing the heat loss of the plasma confinement ring.
As shown in fig. 1-3, in a CCP etching apparatus, the primary function of the plasma confinement ring is to confine the plasma 500 in the discharge region by a plurality of turns of narrow slits (gas channel walls 300) formed by a plurality of turns of cylindrical concentric rings (nested rings). The columns forming the concentric rings are connected by horizontal spokes 301. In order to prevent the plasma leakage, it is generally required that the contact between the plasma confinement ring and the reaction chamber 100 is good, and a relatively large ground capacitance is formed, thereby reducing the rf voltage of the plasma confinement ring. This requires the plasma confinement ring sidewall (annular outer sidewall 302) to be thick (10-20 mm). The rf current path from the plasma confinement ring to the ground or support ring (MGR) is from the plasma 500 to ground along the gas path and the inner sidewall surface of the annular outer sidewall 302 and the interface between the annular outer sidewall 302 and the support ring. The rf current is determined by the loop impedance, while the impedance of the plasma confinement ring to the MGR depends on the amount of capacitance therebetween, which is determined by the contact area and gap height between the plasma confinement ring and the MGR.
At the same time, as the plasma 500 flows through the plasma confinement rings, heat is transferred from the gas to the plasma confinement rings. Cooling (heat flow) channels of the plasma confinement rings (as shown in any one of fig. 1-4): mainly, the heat is collected by the plasma confinement ring concentric ring, conducted to the plasma confinement ring side wall (annular outer side wall 302) through the horizontal spoke 301,
and then conducted to the MGR and the side walls of the reaction chamber through the gap between the plasma confinement rings and the MGR. According to the principle of heat conduction, the temperature T of the plasma confinement ring 1 Can be expressed as:
wherein T is 0 For the reaction chamber sidewall temperature, Q is the amount of heat deposited by the plasma gas onto the plasma confinement rings, k is the (material or medium) thermal conductivity, d is the heat transfer distance from the plasma confinement rings to the MGR, and S is the thermal conductivity area. The plasma confinement ring is generally made of aluminum or aluminum alloy, the side wall of the plasma confinement ring is thick (10-20 mm), and the internal temperature difference is small due to the large thermal conductivity. Thus, the thermal resistance of the plasma confinement rings to the chamber sidewall is primarily determined by the interface between the plasma confinement rings to the MGR. Since the existing design d is very small (<0.5mm, which is a plasma confinement ring-MGR gap, and S (plasma confinement ring bottom area) is large, so that the plasma confinement ring has a good cooling effect, the temperature of the plasma confinement ring is low (generally less than 80 ℃), and polymer accumulation is easy to generate.
Fig. 1 shows a method for blocking heat transfer of a plasma confinement ring and improving the temperature and distribution uniformity of the plasma confinement ring according to one embodiment. Cutting a deep opening (0.5-1 mm wide) at the position of a horizontal spoke of the plasma confinement ring close to the side wall to limit the heat conduction from the spoke to the side wall; a horizontal deep slit with the height of 0.2-2 mm is cut on the side wall of the lower part of the plasma confinement ring along the circumferential direction, and the wall thickness is left to be 0.5-2 mm, so that d is increased and S is decreased, a thermal resistance is formed on the side wall body of the plasma confinement ring, and a large-area heat insulation layer is added. Thus, the heat of the plasma confinement ring can only flow to the side wall of the reaction chamber through the inner remaining thin wall, thereby greatly reducing the heat transfer from the plasma confinement ring to the side wall (shown by the arrow direction in fig. 1). By optimizing the d and S parameters, the transmitted heat can be reduced by more than 90 percent, so that the temperature of the plasma confinement ring is increased to be higher than the melting point (150-200 ℃) of the polymer, and the polymer is prevented from being accumulated on the plasma confinement ring. And, because of increasing the thermal resistance in the horizontal spoke, can also improve the temperature distribution uniformity of plasma confinement ring concentric ring.
In addition, due to the skin effect of the radio frequency current, when the radio frequency is greater than 100kHz, the distribution depth of the radio frequency current on the plasma confinement ring (made of aluminum or aluminum alloy) is less than 0.3mm, and the radio frequency current only flows through the inner surface and the bottom surface of the side wall of the plasma confinement ring. Therefore, the thermal shield slot proposed in this embodiment does not affect the plasma confinement rings to the MGR RF current path, and thus does not affect the plasma distribution in the chamber.
On the other hand, as shown in fig. 5, the present embodiment also provides a plasma processing apparatus including: a reaction chamber in which a susceptor 110 for supporting a substrate is disposed;
a gas injection device 120 for delivering a reaction gas into the reaction chamber;
the plasma confinement ring as described above is disposed around the periphery of the susceptor 110, and the plasma confinement ring is used for exhausting the reaction gas in the reaction chamber.
The embodiment solves the problems that the temperature of the plasma confinement ring is low, so that the pumping channel (gas channel or annular channel) is narrowed, the pumping speed of gas is influenced, and even the pumping channel is blocked, and the high aspect ratio etching process is influenced.
It is understood that in some other embodiments, the thermal isolation gap or plasma confinement ring described above is also suitable for use in an ICP (inductively coupled plasma reactor) chamber. In yet another aspect, the present embodiment also provides a method for processing a semiconductor using the plasma processing apparatus described above, including:
conveying reaction gas to the reaction cavity;
ionizing the reaction gas into plasma and etching the semiconductor substrate on the pedestal in the reaction cavity;
during etching, the plasma-exposed surface of the plasma confinement rings reaches a temperature that prevents polymer deposits generated during etching from forming on the surface.
The embodiment solves the problems that the temperature of the plasma confinement ring is low, so that the pumping channel (gas channel or annular channel) is narrowed, the pumping speed of gas is influenced, and even the pumping channel is blocked, and the high aspect ratio etching process is influenced.
In summary, in the plasma confinement ring provided in the present embodiment, the thermal insulation gap is disposed on the annular sidewall to slow down the heat transfer from the gas channel to the sidewall of the reaction chamber. Namely, the arrangement of the heat insulation gap is equivalent to adding a large-area heat insulation layer on the annular side wall. Therefore, the heat of the plasma confinement ring can only flow to the side wall of the reaction cavity through the residual thin wall on the inner side of the annular side wall, so that the heat transmission from the plasma confinement ring to the side wall is greatly reduced, the temperature of the gas channel can be kept, the distribution uniformity of the gas channel is improved, and the polymer deposition is prevented.
The heat insulation gaps are annular, namely the first gap to the fourth gap are annular, due to the skin effect of radio frequency current, when the radio frequency is higher than 100kHz, the distribution depth of the radio frequency current on the plasma confinement ring (made of aluminum or aluminum alloy) is less than 0.3mm, and the radio frequency current only flows through the inner surface and the bottom surface of the side wall of the plasma confinement ring. Therefore, the thermal isolation gap provided by the invention does not affect the RF current path from the plasma confinement ring to the MGR (support ring), and thus does not affect the plasma distribution in the reaction chamber.
The third slit provided by the present embodiment is located more inside than the fourth slit, so that the heat transfer path from the gas channel of the plasma confinement ring to the sidewall of the reaction chamber is longer, and thus it is easier to maintain the temperature of the plasma confinement ring at the predetermined temperature, thereby preventing polymer deposition.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
In the description of the present invention, it is to be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless expressly stated or limited otherwise, the recitation of a first feature "on" or "under" a second feature may include the recitation of the first and second features being in direct contact, and may also include the recitation that the first and second features are not in direct contact, but are in contact via another feature between them. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. "beneath," "under" and "beneath" a first feature includes the first feature being directly beneath and obliquely beneath the second feature, or simply indicating that the first feature is at a lesser elevation than the second feature.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.
Claims (19)
1. A plasma confinement ring disposed within a reaction chamber of a plasma processing apparatus, the plasma confinement ring comprising an annular sidewall and a gas passage wall fixedly connected to the annular sidewall; the annular side wall is placed on the support ring, the support ring with the lateral wall of reaction chamber is fixed, its characterized in that still includes: thermal insulation slots provided in the annular side wall for slowing down the transfer of heat from the gas channel wall to the side wall of the reaction chamber.
2. The plasma confinement ring of claim 1, wherein the thermal isolation gap comprises: a slit a extending axially along the annular sidewall.
3. The plasma confinement ring of claim 2, wherein the plurality of apertures a is at least two of the group of apertures, wherein two of the apertures a have an opening in the annular sidewall surface and wherein the two openings are in opposite directions.
4. The plasma confinement ring of claim 2, wherein the gap a is located proximate to the gas passage wall.
5. The plasma confinement ring of claim 1, wherein the thermal isolation gap comprises: a slit B extending radially along the annular sidewall.
6. The plasma confinement ring of claim 5, wherein the plurality of slots B is at least two slots in the group, wherein two of the slots B have openings in the annular sidewall surface and the openings are in opposite directions.
7. The plasma confinement ring of claim 5, wherein the gap B is disposed proximate to the support ring.
8. The plasma confinement ring of claim 1, wherein the thermal isolation gap has a gap width of 0.2mm to 2mm.
9. The plasma confinement ring of claim 1, wherein the annular sidewall comprises an annular inner sidewall and an annular outer sidewall, the gas channel wall is located between the annular inner sidewall and the annular outer sidewall, and the thermal isolation gap is located in the annular inner sidewall and/or the annular outer sidewall.
10. The plasma confinement ring of claim 9, wherein the gas passage wall comprises a plurality of concentrically arranged nested rings of different diameters, the plurality of nested rings being fixedly connected to the annular sidewall by spokes at lower portions thereof, the spokes being provided with slits C extending axially along the annular sidewall at the connection with the annular inner sidewall and/or the annular outer sidewall.
11. The plasma confinement ring of claim 10, wherein the gap C has a gap width of 0.5mm to 1mm.
12. The plasma confinement ring of claim 9, wherein the gas passage wall is comprised of a torus having a plurality of through holes.
13. The plasma confinement ring of claim 12, wherein the thermal isolation gap is annular, and a gap C is formed at a junction of the annular body and the annular inner wall and/or the annular outer wall along an axial direction of the annular side wall.
14. The plasma confinement ring of claim 1, wherein the thermal isolation gap is annular.
15. The plasma confinement ring of claim 9, wherein the support ring is a conductor that grounds the plasma confinement ring, the support ring having a slit disposed therein that extends radially of the support ring.
16. The plasma confinement ring of claim 1, wherein the thermal isolation gap is filled with a thermal insulating material.
17. The plasma confinement ring of claim 9, wherein the annular inner sidewall, the annular outer sidewall and the gas passage wall are integrally designed.
18. A plasma processing apparatus, comprising: the device comprises a reaction cavity, a substrate and a substrate support, wherein a base for bearing the substrate is arranged in the reaction cavity;
the gas injection device is used for conveying reaction gas into the reaction cavity;
the plasma confinement ring of any one of claims 1-17, circumferentially disposed about the periphery of the pedestal.
19. A method of processing a semiconductor using the plasma processing apparatus of claim 18, comprising:
conveying reaction gas into the reaction cavity;
ionizing the reaction gas into plasma and etching the semiconductor substrate on the pedestal in the reaction cavity;
during etching, the gas channel wall is maintained at a temperature at which etching polymer is not deposited by slowing the transfer of heat from the gas channel wall to the side walls of the reaction chamber through the thermal isolation gap.
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| CN202110723909.XA CN115547799A (en) | 2021-06-29 | 2021-06-29 | Plasma confinement ring, plasma processing apparatus and method of processing semiconductor |
| TW111116467A TWI834156B (en) | 2021-06-29 | 2022-04-29 | Plasma confinement ring, plasma processing equipment and method of processing semiconductors |
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| US20090139963A1 (en) * | 2007-11-30 | 2009-06-04 | Theodoros Panagopoulos | Multiple frequency pulsing of multiple coil source to control plasma ion density radial distribution |
| US9076826B2 (en) * | 2010-09-24 | 2015-07-07 | Lam Research Corporation | Plasma confinement ring assembly for plasma processing chambers |
| US20140273487A1 (en) * | 2013-03-13 | 2014-09-18 | Applied Materials, Inc. | Pulsed dc plasma etching process and apparatus |
| CN103295870B (en) * | 2013-06-05 | 2016-05-04 | 中微半导体设备(上海)有限公司 | Plasma etching equipment and lithographic method |
| JP6548748B2 (en) * | 2016-01-18 | 2019-07-24 | 株式会社日立ハイテクノロジーズ | Plasma processing method and plasma processing apparatus |
| JP6770868B2 (en) * | 2016-10-26 | 2020-10-21 | 東京エレクトロン株式会社 | Method for impedance matching of plasma processing equipment |
| JP6697372B2 (en) * | 2016-11-21 | 2020-05-20 | キオクシア株式会社 | Dry etching method and semiconductor device manufacturing method |
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