CN101989544B - Structure capable of reducing substrate back polymer - Google Patents
Structure capable of reducing substrate back polymer Download PDFInfo
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- CN101989544B CN101989544B CN2009100560873A CN200910056087A CN101989544B CN 101989544 B CN101989544 B CN 101989544B CN 2009100560873 A CN2009100560873 A CN 2009100560873A CN 200910056087 A CN200910056087 A CN 200910056087A CN 101989544 B CN101989544 B CN 101989544B
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- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 21
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 14
- 229910052710 silicon Inorganic materials 0.000 claims description 14
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- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 8
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Abstract
The invention provides a structure capable of reducing a substrate back polymer. The structure is arranged in a plasma treatment chamber and comprises a focusing ring which surrounds the peripheral side of a base. The focusing ring is provided with an extending part and a conductor ring which is arranged below the back of a substrate and is located between the peripheral side of the base and the extending part of the focusing ring, wherein the extending part at least partially extends below the edge of the back of the substrate. In the invention, the temperature of the back of the substrate is limited through the inserted conductor ring, and thereby, the thermal cracking of carbides on the focusing ring due to the high temperature and the polymer formation on the back of the substrate are limited. The etching uniformity of the substrate is ensured while the substrate back polymer is effectively reduced.
Description
Technical Field
The present invention relates to the field of plasma processing devices, and more particularly, to a structure that can reduce the amount of polymer on the back side of a substrate and ensure uniformity of processing the substrate.
Background
During plasma etching of a substrate, as shown in fig. 1, a susceptor 1 ', a support 3' on a surface of the susceptor 1 ', which is typically an electrostatic chuck 3' (ESC), and a dc electrode 4 'embedded in the electrostatic chuck 3' are provided in a plasma etching chamber. A substrate 2 'to be etched is mounted on the electrostatic chuck 3'. The plasma chamber further comprises an insulating ring 11 ' surrounding the outer circumference side of the susceptor 1 ', the insulating ring 11 ' may be made of quartz; a focus ring 12 ' disposed above the insulating ring 11 ' and adjacent to and surrounding the substrate 2 ', the focus ring 12 ' being disposed simultaneously below a rear peripheral portion of the substrate 2 ', i.e., a gap is provided between an upper surface of the focus ring 12 ' and a rear surface of the substrate 2 '; and a cover ring 14 ' disposed around the focus ring 12 ' for covering the insulating ring 11 '.
In etching, an etching reactant gas (comprised of one or more gases) is energized to energize the gas into a plasma within a plasma processing chamber, and there is Radio Frequency (RF) energy, microwave energy, and/or a magnetic field available to generate and sustain a medium or high density plasma within the plasma processing chamber; because the heating of the plasma causes the focus ring 12 'at the edge of the substrate to have a high temperature above that which thermally cracks the fluorocarbons or hydrocarbons on the focus ring 12', the pyrolyzed fluorocarbons or hydrocarbons will deposit and reform substrate polymer at the relatively low temperature back edge 20 'of the substrate 2' due to the temperature of the substrate 2 'being controlled by a temperature control device (e.g., helium gas flowing between the electrostatic chuck and the substrate) which has a lower temperature than the focus ring 12', resulting in further processing of these deposited polymer in subsequent processing steps. This greatly reduces production efficiency.
Disclosure of Invention
It is an object of the present invention to provide a structure that reduces the amount of polymer on the backside of the substrate while enhancing the uniformity of etching of the substrate.
In order to achieve the above objects, the present invention provides a structure capable of reducing polymers on the backside of a substrate, which surrounds the outer circumference of a substrate pedestal disposed in a plasma processing chamber, wherein the edge of the substrate protrudes from the edge of the upper surface of the pedestal; the structure for reducing the polymer on the back surface of the substrate comprises: a focusing ring surrounding the outer periphery of the base; the focus ring has an extension that extends at least partially below the edge of the backside of the substrate; and a conductive ring disposed below the back surface of the substrate and between the outer peripheral side of the pedestal and the extension of the focus ring.
The conductor ring can be made of silicon, silicon carbide or graphite.
The focus rings (including the first focus ring and the second focus ring) may be made of a semiconductor or conductive material, including silicon (e.g., single crystal silicon or polycrystalline silicon), silicon carbide (e.g., silicon carbide obtained by chemical vapor deposition), aluminum oxide, aluminum nitride, silicon nitride, or quartz, among others. Since the focus ring will be directly exposed to the plasma during plasma etching of the substrate, it may be preferably made of a high purity material, such as silicon (e.g., single or polycrystalline silicon), or silicon carbide (e.g., silicon carbide by chemical vapor deposition), etc.
In another technical solution of the present invention, the focus ring may be separated along an upper surface of the extension portion thereof to form a first focus ring and a second focus ring; wherein the first focusing ring is arranged around the outer periphery of the base; the second focus ring includes an extension that extends at least partially below the edge of the backside of the substrate.
In the present invention, the upper surface of the conductor ring and the upper surface of the focus ring extension are located on the same plane.
In the invention, the plasma processing chamber also comprises an insulating ring surrounding the outer periphery of the base; the focusing ring and the conductor ring are arranged on the insulating ring and cover the top surface of the whole insulating ring.
The insulating ring may be made of a ceramic material (e.g., silicon oxide, i.e., quartz, or aluminum oxide), a polymer material (e.g., polyimide), or the like. Preferably, the insulating ring is made of quartz material.
Further, the structure for reducing polymer on the back surface of the substrate according to the present invention further comprises a cover ring disposed around the outer circumference of the focus ring and covering the upper surface of the insulation ring at the outer diameter. Alternatively, the cover ring may be a radially outwardly extending portion formed on the focus ring, i.e., the cover ring is integrally formed with the focus ring.
Further, the structure for reducing polymer on the back surface of the substrate according to the present invention further comprises a plurality of cooling channels penetrating the insulating ring and transferring the cooling object to the focus ring and/or the conductor ring.
According to the above-described structure for reducing the polymer on the back surface of the substrate, the present invention also provides a plasma processing chamber comprising the structure, the plasma processing chamber having: the device comprises a substrate, a base for placing the substrate, and a structure which surrounds the periphery of the base and can reduce polymers on the back of the substrate; wherein,
the edge of the substrate protrudes out of the edge of the upper surface of the base;
the structure for reducing the polymer on the back surface of the substrate comprises: a focusing ring surrounding the outer periphery of the base; the focus ring has an extension that extends at least partially below the edge of the backside of the substrate; and a conductive ring disposed below the back surface of the substrate and between the outer peripheral side of the pedestal and the extension of the focus ring.
The susceptor also includes a substrate support on an upper surface thereof for mounting a substrate, the substrate support including an electrostatic chuck and a dc electrode embedded in the electrostatic chuck.
In another technical solution of the present invention, the focus ring may be separated along an upper surface of the extension portion thereof to form a first focus ring and a second focus ring; wherein the first focusing ring is arranged around the outer periphery of the base; the second focus ring includes an extension that extends at least partially below the edge of the backside of the substrate.
In the present invention, the upper surface of the conductor ring and the upper surface of the focus ring extension (or the upper surface of the second focus ring) are located on the same plane.
Further, the plasma processing chamber of the invention also comprises an insulating ring surrounding the outer periphery of the pedestal; the focusing ring and the conductor ring are arranged on the insulating ring and cover the top surface of the whole insulating ring.
In the invention, the structure capable of reducing the polymer on the back surface of the substrate further comprises a covering ring arranged around the outer periphery of the focusing ring and covering the upper surface of the insulating ring at the outer diameter position. Alternatively, the cover ring may be a radially outwardly extending portion formed on the focus ring, i.e., the cover ring is integrally formed with the focus ring.
The plasma processing chamber of the present invention further comprises a plurality of cooling channels disposed through the insulating ring and/or the pedestal for delivering cooling objects to the focus ring and/or the conductive ring.
In the above-mentioned technical solution, since the interposed conductor ring has a minimum exposure during the plasma etching of the substrate, and the temperature of the conductor ring does not reach a level at which the carbide on the focus ring is thermally cracked due to the cooling gas supplied through the cooling channel, the formation of the polymer deposited on the back surface of the substrate due to the thermal cracking of the carbide on the focus ring can be restricted, thereby greatly reducing the polymer formed on the back surface of the substrate.
In an alternative embodiment, the present invention further employs a special structure of upper and lower two focusing rings, so that the upper focusing ring (first focusing ring) can be used as a thermal barrier for the lower focusing ring (second focusing ring) closer to the back surface of the substrate, and the lower focusing ring can be kept at a cooler temperature because the heat transfer in the vacuum environment will become slower and the heat transfer between the upper and lower focusing rings will be interrupted directly due to the gap existing between the two focusing rings, i.e., the heat generated by the substrate during etching will be limited and interrupted when the heat is transferred from the upper focusing ring to the lower focusing ring. Thus, the temperature of the lower focus ring does not reach a level at which the carbide on the lower focus ring is thermally cracked during plasma etching of the substrate, so that formation of polymer evaporated and deposited on the back surface of the substrate due to thermal cracking of the carbide on the lower focus ring can be restricted. Since this main reason for forming the polymer on the back surface of the substrate is limited, the polymer formed on the back surface of the substrate can be greatly reduced.
Finally, since the arrangement of the conductor ring in the present invention allows RF coupling between the focus ring and the electrode while minimizing substrate profile tilt, non-uniformity in the plasma density distribution over the substrate surface during etching is not induced, thereby ensuring uniformity of etching.
The invention also provides another technical scheme of a structure capable of reducing the polymer on the back surface of the substrate, which surrounds the outer peripheral side of a substrate base arranged in a plasma processing chamber, wherein the edge of the substrate protrudes out of the edge of the upper surface of the base;
the structure capable of reducing polymer on the back surface of the substrate comprises: a first focus ring surrounding the outer circumference of the base; and a second focus ring positioned below the first focus ring, an end of the second focus ring extending at least partially below the edge of the backside of the substrate; the second focus ring is made of a conductive material.
Wherein, the second focusing ring is made of a conductive material such as silicon, silicon carbide or graphite.
The first focus ring may be made of a semiconductor or conductive material, including silicon (e.g., single crystal silicon or polycrystalline silicon), silicon carbide (e.g., silicon carbide by chemical vapor deposition), aluminum oxide, aluminum nitride, silicon nitride, or quartz, among others. Since the focus ring will be directly exposed to the plasma during plasma etching of the substrate, it may be preferable to make the upper and lower focus rings of a high purity material, such as silicon (e.g., single crystal or polycrystalline silicon), or silicon carbide (e.g., silicon carbide by chemical vapor deposition), etc.
In the invention, the plasma processing chamber also comprises an insulating ring surrounding the outer periphery of the base; the second focusing ring is arranged on the insulating ring and covers the top surface of the whole insulating ring.
Wherein the insulating ring can be made of a ceramic material (such as silicon oxide, i.e. quartz, or aluminum oxide), or a polymer material (such as polyimide), etc.; preferably, the insulating ring is made of quartz material.
Further, the structure for reducing polymer on the back surface of the substrate according to the present invention further comprises a cover ring disposed around the outer circumference of the first focus ring and the second focus ring, and covering the upper surface of the insulating ring at the outer diameter.
Further, the structure for reducing polymer on the back surface of the substrate according to the present invention further comprises a plurality of cooling channels penetrating the insulating ring and transferring the cooling object to the second focus ring.
According to another aspect of the above structure for reducing polymer on the backside of a substrate, the present invention also provides a plasma processing chamber comprising the structure, the plasma processing chamber comprising: the device comprises a substrate, a base for placing the substrate, and a structure which surrounds the periphery of the base and can reduce polymers on the back of the substrate; wherein,
the edge of the substrate protrudes out of the edge of the upper surface of the base;
the structure for reducing the polymer on the back surface of the substrate comprises a first focusing ring, a second focusing ring and a third focusing ring, wherein the first focusing ring is arranged around the outer periphery of the base; and a second focus ring positioned below the first focus ring, an end of the second focus ring extending at least partially below the edge of the backside of the substrate; the second focus ring is made of a conductive material.
In the present invention, the susceptor further comprises a substrate support on an upper surface thereof for mounting a substrate, the substrate support comprising an electrostatic chuck and a dc electrode embedded in the electrostatic chuck.
Further, the plasma processing chamber of the invention also comprises an insulating ring surrounding the outer periphery of the pedestal; the second focusing ring is arranged on the insulating ring and covers the top surface of the whole insulating ring.
In the present invention, the structure for reducing polymer on the back surface of the substrate further comprises a cover ring disposed around the outer circumference of the first focus ring and the second focus ring, and covering the upper surface of the insulating ring at the outer diameter.
The plasma processing chamber of the present invention further comprises a plurality of cooling channels disposed through the insulating ring and/or the pedestal that deliver cooling objects to the second focus ring.
In the second solution mentioned above, it is equivalent to integrate the conductor ring and the second focusing ring in the first solution into a conductor focusing ring surrounding the substrate, which combines the structural features of the inserted conductor ring and the segmented focusing ring, thereby achieving the same technical effect as that achieved by the first solution with more complexity, while simplifying the overall structural configuration. Namely, the formation of polymer deposited on the back surface of the substrate due to thermal cracking of carbide is limited, and the polymer formed on the back surface of the substrate is effectively reduced. And, the conductive focus ring is arranged to allow RF coupling between the focus ring and the electrode while minimizing substrate profile tilt, thereby not causing plasma density distribution nonuniformity on the substrate surface during etching and ensuring etching uniformity.
Drawings
FIG. 1 is a schematic diagram of a prior art structure for producing polymer on the backside of a substrate;
FIG. 2 is a schematic diagram of one embodiment of a structure for reducing polymer on the backside of a substrate according to the present invention;
FIG. 3 is a diagram illustrating a second embodiment of a structure for reducing polymer on the backside of a substrate according to the present invention;
FIG. 4 is a schematic diagram of a third embodiment of a structure for reducing polymer on the backside of a substrate according to the present invention;
FIG. 5 is a diagram illustrating a fourth embodiment of a structure for reducing polymer on the backside of a substrate according to the present invention.
FIG. 6 is a schematic illustration of the structural enhancement of substrate processing uniformity to reduce polymer on the backside of the substrate provided by the present invention.
FIG. 7 is a schematic view showing that the structure of the polymer on the backside of the substrate can reduce the effect on the uniformity of the substrate processing after replacing the conductive ring in FIG. 6 with a dielectric ring.
Detailed Description
The present invention will be described in detail below with reference to preferred embodiments with reference to fig. 2 to 7.
The present invention is applicable to various plasma processing apparatuses, such as: plasma etching, plasma-assisted chemical vapor deposition, or the like. The structure of the present invention will be described below by taking the application of plasma etching as an example. As shown in fig. 2, an embodiment of the present invention for reducing the polymer on the backside of the substrate by inserting a conductor ring 13 is shown. In this embodiment, a substrate 2 and a susceptor 1 are provided in a plasma etching chamber for performing plasma etching on a substrate, and a substrate support 3 for mounting the substrate 2 is further provided on an upper surface 102 of the susceptor 1; the substrate support 3 comprises an electrostatic chuck 3, typically made of a ceramic material, and a dc electrode 4 embedded in the electrostatic chuck 3; the substrate 2 is mounted on the substrate support 3 with its edge protruding from the edge of the upper surface 102 of the susceptor 1 or protruding from the edge of the substrate support 3). The plasma etching chamber further comprises an insulating ring 11 disposed on the outer periphery of the susceptor 1 and surrounding the susceptor 1, which may be made of a ceramic material (e.g., silicon oxide, i.e., quartz, or aluminum oxide), or a polymer material (e.g., polyimide), etc.; preferably, the insulating ring is made of quartz material; the insulating ring 11 may be directly placed on the upper peripheral surface 101 of the base 1, or may be fixed on the upper peripheral surface 101 of the base 1 by other connection means (e.g., screws).
In the plasma etching chamber of this embodiment, there is also a structure for reducing the polymer on the back surface of the substrate, which is disposed on the insulating ring 11 and on the outer periphery side 103 of the susceptor 1; the structure comprises: a focus ring 12 and a conductor ring 13; wherein the focus ring 12 surrounds the outer circumference side 103 of the susceptor 1; it has an extension 123 that extends below the back edge 20 of the substrate 2. The focus ring 12 may be made of a semiconductor or conductive material, including silicon (e.g., single crystal silicon or polycrystalline silicon), silicon carbide (e.g., silicon carbide obtained by chemical vapor deposition), aluminum oxide, aluminum nitride, silicon nitride, or quartz, among others. Since the focus ring 12 will be directly exposed to the plasma during plasma etching of the substrate, it may be preferred to make the focus ring of a high purity material, such as silicon (e.g., single crystal or polycrystalline), or silicon carbide (e.g., silicon carbide by chemical vapor deposition), etc.
The conductor ring 13 is inserted and arranged below the back surface of the substrate 2 and between the focus ring 12 and the base 1, and the upper surface of the conductor ring 13 and the upper surface of the focus ring extension 123 are substantially in the same plane, and the conductor ring 13 is further provided with a proper radial clearance with the focus ring extension 123 and the outer periphery of the base 1 respectively, so as to compensate the tolerance and the changes of thermal expansion and contraction. The conductor ring 13 may be made of silicon, silicon carbide, or graphite.
The invention can reduce the polymer on the back of the substrate and enhance the uniformity of the substrate processing by arranging the conductor ring 13. In one aspect, as shown in FIG. 2, to reduce polymer generation on the backside of the substrate 2, a conductive ring 13 is inserted between the focus ring 12 and the base 1 (including the electrostatic chuck 3) below the backside of the substrate 2, to isolate the focus ring 12 and the base 1 from each other; the conductive ring 13 is spaced apart from the focus ring 12, the susceptor 1 and the back surface of the substrate 2 by a suitable distance. In the low pressure environment of the vacuum processing chamber, no air exists between the gaps, thus the heat conduction between the adjacent elements is cut off, the heat of the very hot focusing ring 12 can not be easily transferred to the conductive ring 13 and the base 1, thereby greatly reducing the temperature of the back surface of the substrate 2, and because the conductive ring 13 has the minimum exposure to plasma, the temperature of the conductive ring in the etching process is lower than the temperature for reaching thermal cracking, the thermal cracking of carbide reaching the lower part of the edge of the substrate can be effectively prevented, and finally the purpose of reducing the deposition of thermally cracked molecules from the back surface of the substrate 2 and forming polymers is achieved. The conductive ring 13 is located on the insulating ring 11, and it can also be integrated with the upper surface of the insulating ring 11; the conductive ring 13 may be made of a conductive material or a semiconductor material.
On the other hand, the conductor ring 13 can also enhance the uniformity of processing to the substrate. Fig. 6 is a schematic diagram of the structural enhancement of substrate processing uniformity provided by the present invention to reduce polymer on the backside of the substrate. The conductive ring 13 is a conductive material (e.g., Si or SiC) having electrical properties similar to those of the material used for the electrostatic chuck 3 and the substrate 2 thereon and the peripheral focus ring 12, so that a more uniform potential distribution can be obtained from the rf electrode 1 (the rf power supply is often connected to the susceptor 1, and thus the susceptor 1 also functions as the rf electrode 1) to through the conductive ring 13 and the focus ring 12. The distribution of the equipotential lines 30b near the edge of the substrate 2 can be made more parallel to the plane of the substrate 2, and the electric field lines 30a perpendicular to the equipotential lines 30b can accelerate the ions in the plasma in the direction of 30a towards the surface of the substrate 2 to plasma-process the substrate 2. In particular, at the edge portion of the substrate 2, the electric field lines 301 above the substrate edge are also substantially perpendicular to the surface of the substrate 2 due to the conductive ring 13, which reduces the tilting (tilting) of the processed devices (e.g., etched holes) at the substrate edge. Therefore, the invention also enhances the uniformity of the plasma density distribution to a certain extent on the basis of minimizing the substrate profile inclination. Because the insert ring 13 made of conductive material is used, more RF energy is transmitted from the lower electrode 1 to the edge of the substrate 2 through the conductive ring 13, so that the plasma density distribution of plasma on the substrate surface in the etching process is not uneven, thereby ensuring the uniformity of etching.
Referring to fig. 7 for comparison with fig. 6, fig. 7 is a schematic diagram illustrating the effect of the dielectric ring 13 'on the uniformity of the substrate processing after replacing the conductive ring 13 with the dielectric ring 13' in the structure of fig. 6 for reducing the polymer on the backside of the substrate. As shown in FIG. 7, the potential drops sharply from the RF electrode 1 to the position passing through the dielectric ring 13 'due to the presence of the dielectric ring 13', so that the equipotential lines 30b 'at the edge of the substrate 2 are bent sharply at the edge position of the substrate 2, and since the electric field lines 301' should be perpendicular to the equipotential lines 30b ', the electric field lines 301' at the edge of the substrate 2 are at an angle different from 90 degrees to the surface of the substrate, when the ions in the plasma are incident obliquely (i.e., at an angle different from 90 degrees) to the surface of the substrate 2, the profile of the processed device (e.g., the etched hole) at the edge of the substrate 2 to be processed is inclined, and the incident ion energy and ion density distribution are different, thereby causing non-uniform etching effect.
The present invention can be modified in various ways without departing from the spirit and substance of the invention. For example, the structure shown in fig. 2 may further optionally include a cover ring 14, where the cover ring 14 is disposed around the focus ring 12 and covers the upper surface 111 at the outer diameter of the insulating ring 11, and the cover ring is made of an insulating material or a conductive material.
As shown in fig. 2, the conductor ring 13 and the focus ring 12 are both disposed on the insulating ring 11. The entire top surface of the insulating ring 11 is now covered by the focus ring 12 and the conductor ring 13, which reduces the exposure of the top surface of the insulating ring 11 to plasma and/or reactive species of the plasma during the etching process.
Cooling channels may also be provided through the insulating ring 11 and/or the susceptor 1 to deliver a cooling fluid (e.g., helium or water) to adjacent surfaces of the focus ring 12 and/or the conductive ring 13, such as helium delivered to the gap between the conductive ring 13 and the susceptor 1 and the electrostatic chuck 3, and/or to the gap between the focus ring 12 and the conductive ring 13, and/or to the interface between the focus ring 12 and the insulating ring 11, to further rapidly reduce the temperature of the backside of the substrate during etching, to reduce heat, and to further reduce polymer deposition from etching gases and/or volatile byproducts on the backside of the substrate.
In another embodiment of the present invention, as shown in FIG. 3, the structural arrangement and operating principle within the plasma etching chamber is similar to that shown in FIG. 2, except that in FIG. 3 the top surface of the insulating ring 11 includes only the focus ring 12, or, in other words, the cover ring 14 as shown in FIG. 2 is a radially outwardly extending portion formed on the focus ring 12, i.e., in FIG. 3 the cover ring 14 is integrally formed with the focus ring 12. At this time, the cover ring 14 and the focus ring 12 are made of the same material.
In another embodiment of the present invention, as shown in FIG. 4, the arrangement and operation of the structure within the plasma etch chamber is similar to that shown in FIG. 2, except that the focus ring is spaced along the upper surface of its extension 123 to form a first focus ring 121 and a second focus ring 122 located therebelow; wherein the first focus ring 121 is disposed around the outer circumference of the susceptor 1; the extension 123 included in the second focus ring 122 still extends to below the edge of the back surface of the substrate 2, and the upper surface of the second focus ring 122 is the upper surface of the original focus ring extension 123, that is, in this embodiment, the upper surface of the second focus ring 122 and the upper surface of the conductive ring 13 are substantially in the same plane.
In the embodiments described above and shown in fig. 2 and 3, when a substrate is undergoing plasma etching, the etching reactant gas (consisting of one or more gases) is energized to energize the gas into a plasma within the plasma chamber, and there is Radio Frequency (RF) energy, microwave energy, and/or a magnetic field within the plasma chamber that can be used to generate and sustain a medium or high density plasma; at this time, the substrate 2 generates a large amount of heat during the etching process, and since the conductor ring 13 has a minimum exposure and the temperature of the conductor ring 13 does not reach a level at which the carbide is thermally cracked due to the auxiliary effect of the cooling gas such as helium gas supplied through the cooling channel, the carbide reaching the edge of the substrate can be prevented from encountering the thermally cracked part at a higher temperature to be evaporated and then deposited on the back surface of the substrate 2, so that the polymer formed on the back surface of the substrate can be greatly reduced.
Further, in the embodiment shown in fig. 4, since the upper and lower two focus rings are adopted, the upper first focus ring 121 can be used as a thermal barrier for the lower second focus ring 122 closer to the back surface of the substrate 2, since the heat transfer in the vacuum environment will become slower, and since the gap between the upper and lower focus rings will directly cause the interruption of the heat transfer, the lower focus ring 122 can be kept at a lower temperature after the heat transfer from the upper focus ring 121 to the lower focus ring 122 is limited and interrupted. Therefore, during the plasma etching process of the substrate, the temperature of the lower focus ring 122 does not reach a level at which the carbide on the lower focus ring is thermally cracked, so that the formation of the polymer evaporated and deposited on the back surface of the substrate due to the thermal cracking of the carbide on the lower focus ring 122 can be further restricted, thereby more effectively reducing the polymer formed on the back surface of the substrate 2.
As shown in fig. 5, an embodiment of the present invention for reducing polymer on the backside of a substrate by providing a conductive focus ring is shown. This embodiment is actually a combined application of the embodiments shown in fig. 2 and 4, and some components in the plasma etching chamber, including the base 1, the substrate 2, the electrostatic chuck 3 and the dc electrode 4 embedded in the electrostatic chuck 3, and the insulating ring 11, the cover ring 14 and the upper first focusing ring 121 disposed around the outer periphery of the base 1, are disposed in the same manner as the foregoing embodiments shown in fig. 2 or 4, and have the same technical features and technical effects as those achieved. In this embodiment, the conductive ring 13 of the embodiment shown in fig. 4 and the second focus ring 122 on the back surface of the substrate are simply integrated to form a conductive focus ring 131 (as shown in fig. 5) made of a conductive material, and the conductive focus ring 131 may be made of silicon, silicon carbide, or graphite. A thin coating may also be interposed between the upper and lower focus rings, which has the effect of further inhibiting heat transfer. The gap is arranged between the 2 segmented focusing rings to achieve better heat insulation and temperature reduction effects in a vacuum environment.
Since the present embodiment combines the structural features of the inserted conductor ring and the segmented focus ring, and the focus ring below the segmented conductor is formed, the same technical effects as those achieved by the above embodiment (fig. 2, 3 and 4) with a more complex structure can be achieved on the basis of simplifying the whole structural composition. Namely, the formation of the polymer evaporated and deposited on the back surface of the substrate due to the thermal cracking of the carbide is limited, and the polymer formed on the back surface of the substrate is effectively reduced. And, the conductive focus ring is arranged to allow RF coupling between the focus ring and the electrode while minimizing substrate profile tilt, thereby not causing plasma density distribution nonuniformity on the substrate surface during etching and ensuring etching uniformity.
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 (28)
1. A substrate backside polymer reduction structure that surrounds an outer perimeter side of a pedestal (1) of a substrate (2) disposed in a plasma processing chamber, an edge of the substrate (2) protruding beyond an edge of an upper surface (102) of the pedestal (1), the substrate backside polymer reduction structure comprising:
a focus ring (12) disposed around an outer peripheral side of the susceptor (1); the focus ring (12) having an extension (123) extending at least partially below the edge of the back side of the substrate (2); and
a conductive ring (13) disposed below the back surface of the substrate (2) and between the outer peripheral side of the base (1) and the extension (123) of the focus ring (12).
2. The structure for reducing polymer on the backside of a substrate as claimed in claim 1, wherein the conductor ring (13) is made of silicon, silicon carbide or graphite.
3. The structure for reducing polymer on the backside of a substrate as claimed in claim 1, wherein the focus ring (12) is made of silicon, silicon carbide, aluminum oxide, aluminum nitride, silicon nitride, or quartz.
4. The structure for reducing polymer on the backside of a substrate as claimed in claim 3, wherein the focus ring (12) is separated along the upper surface of the extension (123) to form a first focus ring (121) and a second focus ring (122); wherein,
the first focusing ring (121) is arranged around the outer periphery of the base (1);
the second focus ring (122) includes an extension (123) that extends at least partially below the edge of the back side of the substrate (2).
5. The structure for reducing polymer on the backside of a substrate as claimed in claim 1, wherein the upper surface of the conductor ring (13) and the upper surface of the focus ring extension (123) are coplanar.
6. The structure for reducing polymer on the backside of a substrate as claimed in claim 1, wherein the plasma processing chamber further comprises an insulating ring (11) surrounding the outer periphery of the susceptor (1); the focusing ring (12) and the conductor ring (13) are arranged on the insulating ring (11) and cover the top surface of the whole insulating ring (11).
7. The structure for reducing polymer on the backside of a substrate as claimed in claim 6, further comprising a cover ring (14) disposed around the outer circumference of the focus ring (12) and covering the upper surface (111) at the outer diameter of the insulating ring (11).
8. The structure for reducing polymer on the backside of a substrate as claimed in claim 7, wherein the cover ring (14) is a radially outwardly extending portion formed on the focus ring (12), i.e. the cover ring (14) is integrally formed with the focus ring (12).
9. The structure for reducing polymer on the backside of a substrate as claimed in claim 6, further comprising a plurality of cooling channels penetrating the insulating ring (11) and transferring cooling objects to the focus ring (12) and/or the conductor ring (13).
10. A plasma processing chamber comprising a substrate (2), a susceptor (1) for placing the substrate (2), and a structure surrounding an outer peripheral side of the susceptor (1) for reducing polymer on a backside of the substrate; wherein,
the edge of the substrate (2) protrudes out of the edge of the upper surface (102) of the base (1);
the structure for reducing the polymer on the back surface of the substrate comprises:
a focus ring (12) disposed around an outer peripheral side of the susceptor (1); the focus ring (12) having an extension (123) extending at least partially below the edge of the back side of the substrate (2); and
a conductive ring (13) disposed below the back surface of the substrate (2) and between the outer peripheral side of the base (1) and the extension (123) of the focus ring (12).
11. A plasma processing chamber according to claim 10, characterized in that the base (1) further comprises a substrate support on its upper surface (102) for mounting the substrate (2), the substrate support comprising an electrostatic chuck (3) and a dc electrode (4) embedded in the electrostatic chuck (3).
12. The plasma processing chamber of claim 10, wherein said focus ring (12) is spaced along an upper surface of its extension (123) to form a first focus ring (121) and a second focus ring (122); wherein,
the first focusing ring (121) is arranged around the outer periphery of the base (1);
the second focus ring (122) includes an extension (123) that extends at least partially below the edge of the back side of the substrate (2).
13. The plasma processing chamber of claim 10, wherein an upper surface of said conductor ring (13) and an upper surface of said focus ring extension (123) are coplanar.
14. The plasma processing chamber according to claim 10, further comprising an insulating ring (11) surrounding an outer circumferential side of said susceptor (1); the focusing ring (12) and the conductor ring (13) are arranged on the insulating ring (11) and cover the top surface of the whole insulating ring (11).
15. The plasma processing chamber of claim 14, wherein the structure for reducing polymer on the backside of the substrate further comprises a cover ring (14) disposed around the outer periphery of the focus ring (12) and covering the upper surface (111) at the outer diameter of the insulating ring (11).
16. A plasma processing chamber according to claim 15, characterized in that the cover ring (14) is a radially outwardly extending portion formed on the focus ring (12), i.e. the cover ring (14) is formed integrally with the focus ring (12).
17. The plasma processing chamber according to claim 14, further comprising a plurality of cooling channels extending through the insulating ring (11) and/or the susceptor (1) and delivering cooling objects to the focus ring (12) and/or the conductor ring (13).
18. A structure for reducing polymer on the backside of a substrate, surrounding the outer periphery of a pedestal (1) of a substrate (2) disposed in a plasma processing chamber, the edge of the substrate (2) protruding beyond the edge of the upper surface (102) of the pedestal (1); the structure capable of reducing polymer on the back surface of the substrate comprises:
a first focus ring (121) disposed around an outer circumferential side of the susceptor (1); and
a second focus ring (131) located below the first focus ring (121), an end (123) of the second focus ring (131) extending at least partially below the edge of the back side of the substrate (2);
the second focusing ring (131) is made of a conductive material.
19. The structure for reducing polymer on the backside of a substrate of claim 18, wherein the second focus ring (131) is made of silicon, silicon carbide, or graphite.
20. The structure for reducing polymer on the backside of a substrate as claimed in claim 18, wherein the first focus ring (121) is made of silicon, silicon carbide, aluminum oxide, aluminum nitride, silicon nitride, or quartz.
21. The structure for reducing polymer on the backside of a substrate as claimed in claim 18, wherein the plasma processing chamber further comprises an insulating ring (11) disposed around the outer periphery of the susceptor (1); the second focusing ring (131) is arranged on the insulating ring (11) and covers the whole top surface of the insulating ring (11).
22. The structure for reducing polymer on the backside of a substrate as claimed in claim 21, further comprising a cover ring (14) disposed around the outer circumference of the first focus ring (121) and the second focus ring (131) and covering the upper surface (111) at the outer diameter of the insulating ring (11).
23. The structure for reducing polymer on the backside of a substrate as claimed in claim 21, further comprising a plurality of cooling channels disposed through the insulating ring (11) for delivering cooling objects to the second focus ring (131).
24. A plasma processing chamber comprising a substrate (2), a susceptor (1) for placing the substrate (2), and a structure surrounding an outer peripheral side of the susceptor (1) for reducing polymer on a backside of the substrate; wherein,
the edge of the substrate (2) protrudes out of the edge of the upper surface (102) of the base (1);
the structure for reducing the polymer on the back surface of the substrate comprises:
a first focus ring (121) disposed around an outer circumferential side of the susceptor (1); and
a second focus ring (131) located below the first focus ring (121), the second focus ring
One end (123) of the two focus rings (131) extends at least partially below the edge of the back side of the substrate (2);
the second focusing ring (131) is made of a conductive material.
25. The plasma processing chamber of claim 24, wherein the base (1) further comprises a substrate support on an upper surface (102) thereof for mounting the substrate (2), the substrate support comprising an electrostatic chuck (3) and a dc electrode (4) embedded in the electrostatic chuck (3).
26. A plasma processing chamber according to claim 24, further comprising an insulating ring (11) surrounding an outer circumferential side of said susceptor (1); the second focusing ring (131) is arranged on the insulating ring (11) and covers the whole top surface of the insulating ring (11).
27. The plasma processing chamber of claim 26, wherein the structure for reducing polymer on the backside of the substrate further comprises a cover ring (14) disposed around the outer periphery of the first focus ring (121) and the second focus ring (131) and covering the upper surface (111) at the outer diameter of the insulating ring (11).
28. The plasma processing chamber according to claim 26, further comprising a plurality of cooling channels extending through the insulating ring (11) and/or the susceptor (1) and delivering cooling objects to the second focus ring (131).
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| US8603908B2 (en) * | 2011-05-06 | 2013-12-10 | Lam Research Corporation | Mitigation of silicide formation on wafer bevel |
| CN103165494B (en) * | 2011-12-08 | 2015-12-09 | 中微半导体设备(上海)有限公司 | A kind of apparatus and method of clean wafer back polymer |
| CN103456623A (en) * | 2012-05-29 | 2013-12-18 | 上海宏力半导体制造有限公司 | Etching control method for reducing deposition of polymers at edges of wafers |
| CN103794460B (en) * | 2012-10-29 | 2016-12-21 | 中微半导体设备(上海)有限公司 | The coating improved for performance of semiconductor devices |
| CN104124126B (en) * | 2013-04-26 | 2016-12-28 | 北京北方微电子基地设备工艺研究中心有限责任公司 | A kind of bogey and plasma processing device |
| US11043364B2 (en) | 2017-06-05 | 2021-06-22 | Applied Materials, Inc. | Process kit for multi-cathode processing chamber |
| CN108511312B (en) * | 2018-03-29 | 2020-04-10 | 长江存储科技有限责任公司 | Wafer bonding plasma processing device |
| JP7115942B2 (en) * | 2018-09-06 | 2022-08-09 | 東京エレクトロン株式会社 | PLACE, SUBSTRATE PROCESSING APPARATUS, EDGE RING AND TRANSFER METHOD OF EDGE RING |
| CN113078091B (en) * | 2020-01-06 | 2023-03-14 | 中芯国际集成电路制造(北京)有限公司 | Wafer sucking disc protection device and semiconductor manufacturing equipment |
| KR102562892B1 (en) * | 2022-12-29 | 2023-08-03 | 주식회사 기가레인 | Electrostatic chuck unit and plasma etching apparatus having the same |
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| DE10143718A1 (en) * | 2001-08-31 | 2003-03-27 | Infineon Technologies Ag | Mounting device for wafer in plasma etching plant has sealant introduced into free space between wafer and electrode |
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