CN213583694U - Lower electrode assembly and plasma processing device - Google Patents
Lower electrode assembly and plasma processing device Download PDFInfo
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- CN213583694U CN213583694U CN202023070019.3U CN202023070019U CN213583694U CN 213583694 U CN213583694 U CN 213583694U CN 202023070019 U CN202023070019 U CN 202023070019U CN 213583694 U CN213583694 U CN 213583694U
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Abstract
The utility model provides a lower electrode subassembly and plasma processing apparatus who locates, the utility model discloses a set up the protection ring and cover the screw on weld line and the base between base and edge ring subassembly, reduce the clearance between edge ring subassembly and the base simultaneously, and set up the protective layer in the base outside, the plasma of having avoided substrate and focus ring top leaks in the clearance between base and the edge ring subassembly, plasma corrosion base and accessory thereof have been prevented, the electric arc discharge's that lower electrode subassembly probably appears possibility has been reduced, and block the probability that screw department produced electric arc on the not enough weld line of protective layer cover and the base, the effectual safe in utilization who guarantees lower electrode subassembly.
Description
Technical Field
The utility model relates to a plasma sculpture technical field especially relates to a plasma processing technology field who prevents down electrode subassembly and produce electric arc under high radio frequency power.
Background
Micromachining of semiconductor substrates or substrates is a well-known technique that may be used to fabricate, for example, semiconductors, flat panel displays, Light Emitting Diodes (LEDs), solar cells, and the like. An important step in microfabrication is a plasma processing process step, which is performed inside a reaction chamber into which process gases are introduced. An rf source is inductively and/or capacitively coupled to the interior of the chamber to excite the process gases to form and maintain a plasma. Inside the reaction chamber, the exposed substrate is supported by the lower electrode assembly and fixed in a fixed position by some clamping force to ensure the safety of the substrate and high yield of processing in the process.
The lower electrode assembly comprises an electrostatic chuck for fixing a substrate, a base for supporting the electrostatic chuck, and an edge ring assembly arranged around the base, and is used for supporting and fixing the substrate and controlling the temperature, electric field distribution and the like of the substrate in the process of processing the substrate.
In the prior art, a common material of the base is aluminum, and a material of the dielectric ring surrounding the periphery of the base is generally a ceramic material, and because the difference between the thermal expansion coefficients of the base and the dielectric ring is large, a certain space is required to be arranged between the dielectric ring and the base to accommodate the thermal expansion and contraction of the base in order to ensure that the base works in a large temperature range.
As the processing precision of the substrate is higher and higher, the radio frequency power applied to the reaction cavity is higher and higher. High rf power is likely to generate arc discharge in a narrow space in the reaction chamber, damaging the susceptor and its peripheral components, and seriously threatening the stability and safety of the operation of the lower electrode assembly, so a solution is urgently needed to meet the continuously improved rf applied power and the requirement of the processing uniformity of the substrate.
SUMMERY OF THE UTILITY MODEL
In order to solve the above technical problem, the utility model provides a lower electrode assembly for bear pending substrate, include:
the base comprises a base body and a step part extending outwards from the base body, and a welding line is arranged on the base body;
an electrostatic chuck located above the pedestal;
an edge ring assembly disposed around the pedestal and/or electrostatic chuck with a gap therebetween;
the gap is provided with a first protection ring, and the first protection ring covers the welding line.
Optionally, a protective layer is disposed on an outer side of the base.
Optionally, the protective layer is an alumina and/or yttria material layer, or a hard anodized layer.
Optionally, the stepped portion has a screw hole, and the first protective ring covers at least a part of an edge of the screw hole.
Optionally, the first protection ring covers an edge of the screw hole located in the gap.
Optionally, the gap includes a first gap and a second gap, the first gap is located above the first protection ring, the second gap is located below the first gap, and the interval of the second gap is greater than the interval of the first gap.
Optionally, a corner between the first void and the second void is in contact with the first protection ring.
Optionally, the electrostatic chuck further comprises a second protection ring, wherein the second protection ring is arranged at the interface of the pedestal and the electrostatic chuck.
Optionally, at least a portion of the second protective ring abuts the pedestal body and the edge ring assembly.
Optionally, a groove is provided at a contact position of the first protection ring and/or the second protection ring with the base body and/or the edge ring assembly, and a cross section of the groove is arc-shaped or frame-shaped.
Optionally, the first protective ring and the second protective ring are made of a plasma corrosion resistant material.
Optionally, the first protective ring and the second protective ring are made of a polymer material.
Optionally, the first protective ring and the second protective ring are of a fluoroelastomer or perfluororubber series.
Further, the present invention also provides a plasma processing apparatus, which comprises a vacuum processing chamber, wherein the vacuum processing chamber comprises the lower electrode assembly.
The utility model has the advantages that: the utility model provides a plasma corrosion resistant lower electrode subassembly and plasma processing apparatus, through covering the protection ring on the weld line at the base, improve the dielectric capacity in edge ring subassembly and base clearance, avoid letting out the contact of plasma and protective layer unevenness department simultaneously, prevent that plasma from corroding base and accessory, the arc discharge's that lower electrode subassembly probably appears possibility has been reduced, and block the clearance below and take place the extension of arc discharge back to last, the effectual safe in utilization who guarantees lower electrode subassembly.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 shows a schematic structural diagram of a capacitively-coupled plasma processing apparatus;
FIG. 2 shows a schematic view of a partial lower electrode assembly structure;
FIG. 3 shows a partial bottom electrode assembly structure schematic of another embodiment;
FIG. 4 shows a partial bottom electrode assembly structure schematic of another embodiment;
FIG. 5 is a partial bottom electrode assembly structure schematic of another embodiment;
FIG. 6 is a partial bottom electrode assembly structure schematic of another embodiment;
FIG. 7 is a partial bottom electrode assembly structure schematic of another embodiment;
fig. 8 is a schematic view showing a structure of an inductively coupled plasma processing apparatus.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Fig. 1 shows a schematic view of a capacitively coupled plasma processing apparatus, which includes an evacuable reaction chamber 100 surrounded by an outer wall 10. The reaction chamber 100 is used to process a substrate 103. The reaction chamber comprises a lower electrode assembly inside, and is used for supporting the substrate and controlling the substrate temperature, the electric field and other factors influencing the substrate processing. The lower electrode assembly comprises a base 101 for bearing an electrostatic chuck 102, a temperature control device is arranged in the base 101 for realizing the temperature control of an upper substrate, the electrostatic chuck 102 for bearing a substrate 103, and a direct current electrode is arranged in the electrostatic chuck, and the direct current electrode generates direct current adsorption between the back surface of the substrate and the bearing surface of the electrostatic chuck so as to realize the fixation of the substrate. An edge ring assembly 20 is provided around the periphery of the pedestal and electrostatic chuck for adjusting the temperature, electric field distribution, etc. at the edge region of the substrate. Disposing a plasma confinement ring 108 around the edge ring assembly 20, between the edge ring assembly 20 and the chamber sidewall, for confining a plasma to the reaction region while allowing gas to pass therethrough; the grounding ring 109, located below the plasma confinement ring, functions to provide electric field shielding to prevent plasma leakage. A bias RF power supply, typically applying a bias RF signal to the lower electrode assembly, controls the direction of plasma bombardment. The utility model discloses a lower electrode subassembly can be used for the capacitively coupled plasma processing apparatus as shown in figure 1.
In the capacitively-coupled plasma processing apparatus shown in fig. 1, an upper electrode assembly is included in addition to a lower electrode assembly, and the upper electrode assembly includes a gas shower head 30 for introducing a process gas in a gas supply apparatus into the reaction chamber. And a high-frequency radio frequency power source applies a high-frequency radio frequency signal to at least one of the upper electrode assembly or the lower electrode assembly so as to form a radio frequency electric field between the upper electrode assembly and the lower electrode assembly, and excites the process gas in the reaction cavity into plasma, thereby realizing the treatment of the plasma on the substrate to be treated.
Fig. 2 illustrates a partial lower electrode assembly structure in which a lower electrode assembly includes: a focus ring 201 disposed around the susceptor 101 and/or the electrostatic chuck 102 and the substrate 103 for adjusting the temperature, electric field distribution, etc. of the edge region of the substrate 103; a dielectric ring 202 is disposed below the focus ring 201, and the dielectric ring 202 is used to maintain the potential difference between the focus ring 201 and the base 101 and to adjust the temperature of the focus ring 201.
The base 101 is typically made of an electrically conductive metal, such as aluminum, and the dielectric ring 202 surrounding the base is typically made of a ceramic material, preferably a highly thermally conductive ceramic material, which may also be Al2O3In order to avoid the extrusion of the components due to the different thermal expansion coefficients of the base 101 and the dielectric ring 202, a certain gap 105 needs to be provided between the dielectric ring 202 and the base 101 during the mounting process. As the processing precision of the substrate is higher and higher, the radio frequency power applied to the reaction cavity is higher and higher. High RF power easily enters narrow space in the reaction chamberArc discharge is generated in the chamber, the base and peripheral components of the base are damaged, and the working stability and safety of the lower electrode component are seriously threatened. In the manufacturing process of the base, in order to process the pipe inside the base 101 for controlling the temperature or accommodating the lift pin, the base needs to be divided into several parts to be machined and welded together after machining, the welding line 1013 is exposed in the gap 105, the welding line is a weak point due to the difference between the micro-morphology or the material and the non-welding part, so the welding line 1013 is more likely to become an end point of the electric arc, furthermore, as shown by the dotted line on the step 1012 of the base 101 in fig. 2, in order to fix the screw hole used by the base 101, the electric arc is likely to occur due to the tip of the edge of the screw hole, even if the outer surface of the base 101 is covered with a protective layer to block the exposure of the metal base, the exposed parts, namely the welding line 1013 and the screw hole, especially for the screw hole, it is difficult to cover an effective protective layer due to the process limitation, therefore, when the bias voltage increases, the arc discharge is first generated. One method of improvement is to use paschen's law:
the breakdown voltage between two electrodes in a gas is a function of pressure and gap length according to Paschen's law, where VbIs the breakdown voltage, A and B are constants associated with the gas, p is the gas pressure, d is the gap distance, γseIs the secondary electron emission coefficient. Can improve breakdown voltage through the size that reduces p or d, and then reduce the probability that plasma took place the electric arc, one of the principle that the utility model utilizes reaches through reducing d promptly.
Fig. 2 is a schematic view of an embodiment of the present invention, in this embodiment, the base 101 includes a base body 1011 and a step portion 1012 extending outward from the base body 1011, and the dielectric ring 202 can be placed on the step portion 1012 of the base 101 by the gravity of the dielectric ring 202 itself or by an externally applied pressure, so as to form a gap 105 with the base body 1011 for accommodating thermal expansion and contraction of the component. Wherein a first protective ring 104 is provided in the gap 105 for covering the weld line 1013. The arcing resulting from the breakdown may occur at the exposed metal of the substrate 103 and the base 101, such as an unprotected bond wire, or other metal corners not covered by the protective layer, so that the arcing may damage the base 101 and also the substrate 103. The first protection ring 104 reduces the gap distance d, and the contact between the first protection ring 104 and the bonding wire 1013 also increases the dielectric coefficient between the substrate 103 and the bonding wire 1013, and if an arc is to be generated between the substrate 103 and the bonding wire 1013, in addition to puncturing the gas in the gap, the first protection ring 104 is also punctured, and in some embodiments, the first protection ring 104 is made of fluororubber or perfluororubber, which not only has the technical effect of resisting plasma corrosion, but also provides a sufficiently high dielectric function, and when the plasma etching process is performed, the first protection ring 104 will thermally expand to contact the dielectric ring 202, so as to block the passage of the plasma into the bottom of the gap 105 to contact the screw hole, that is, to reduce the possibility of the arc generation between the substrate 103 and the edge of the screw hole. Optionally, a protective layer 106 is disposed on the outer side of the base 101, and is made of a plasma corrosion resistant material, typically an aluminum oxide material, or an yttrium oxide material, which can increase the breakdown voltage, prevent arc discharge between the low voltage of the plasma and the high voltage of the base, and further improve the safety of the lower electrode assembly.
Fig. 3 is a schematic view of another embodiment of the present invention, which is different from the above embodiments in that the gap 105 is divided into two parts, i.e., a first gap 1501 and a second gap 1502, the first gap 1501 is located above the first protection ring 104, the second gap 1502 is located below the first gap 1501, and the distance between the second gaps 1502 is larger than the first gap 1501. In the embodiment shown in fig. 3, the second gap 1502 is formed by recessing the bottom of the dielectric ring 202 on the side of the gap 105, and the second gap 1502 can provide more space for the first protection ring 104, on one hand, the space can allow the first protection ring 104 to cover more screw hole edges, further reducing the probability of arcing at the screw hole edges, and on the other hand, the second gap 1502 can provide an expansion space for the first protection ring 104, so that the first protection ring 104 can fill the second gap 1502 when performing the etching process, and the dielectric ring 104 can not be damaged by excessive expansion. Meanwhile, when the first protection ring 104 expands upwards due to heating, the first protection ring contacts with the top end of the concave part of the dielectric ring 202, namely the gap 105 is divided, so that the space for gas diffusion is reduced, the probability of generation of arc discharge can be effectively reduced, and the safe voltage working range of the lower electrode assembly is improved.
Fig. 4 is a schematic view of another embodiment of the present invention, which is different from the above embodiments in that the second gap 1502 is formed by the base body 1011 recessed from the bottom of the side of the gap 105, the second gap 1502 can provide more space for the first protection ring 104, and when performing the etching process, the first protection ring 104 can fill the second gap 1502 without excessively expanding and damaging the dielectric ring 104. Meanwhile, by the recess, the first protection ring 104 can be better contacted with the welding wire 1013, and a tighter covering effect is achieved.
Fig. 5 is a schematic view of another embodiment of the present invention, and in this embodiment, the difference from the above embodiment is that the second gap 1502 is formed by the base body 1011 and the dielectric ring 202 being located at the bottom of the side of the gap 105 and being recessed at the same time, such design can give consideration to the technical effects of the embodiments of fig. 3 and 4, i.e. damage to the lower electrode assembly during expansion can be avoided, and the lower electrode assembly can better cover the screw hole edge on the welding line 1013 and the step portion of the base, so as to achieve better arc-avoiding effect.
Fig. 6 is a schematic view of another embodiment of the present invention, which is different from the above embodiments in that the second gap 1502 is formed by recessing the bottom of the dielectric ring 202 on the side of the gap 105, and the corner between the second gap 1502 and the first gap 1501 contacts the top of the first protection ring 104, so that the plasma can be isolated from entering the space between the dielectric ring 202 and the first protection ring 104 before the first protection ring 104 is fully expanded to fill the recess, and if the plasma enters the region, the ignition discharge can be more easily generated in combination with the edge of the screw hole on the step portion.
Fig. 7 is a schematic diagram of another embodiment of the present invention, which is different from the above embodiments in that a second protection ring 1041 is further included, and the second protection ring 1041 surrounds the peripheries of the pedestal 101 and the electrostatic chuck 102, and at least partially abuts against the dielectric ring 202. The plasma processing device can prevent plasma from bombarding the connecting layer between the electrostatic chuck and the base 101, the connecting layer is mostly made of silica gel and is easy to corrode by the plasma, if the connecting layer is corroded, the problems of internal gas leakage or uneven surface temperature of a substrate and the like can be caused, and the plasma can be further prevented from entering the gap 105, so that the possibility of arc discharge is reduced. Meanwhile, the second protection ring 1041 is located between the pedestal 101 and the focus ring 201, so that the pedestal 101 and the focus ring 201 are electrically isolated, and in addition, the second protection ring 1041 is used for preventing plasma from entering the gap 105 through a gap between the focus ring and the pedestal or the electrostatic chuck, so that the capability of avoiding arc in the gap 105 is enhanced, and the possibility of the protective layer 106 on the pedestal being corroded by the plasma is reduced.
Optionally, a thermally conductive layer is disposed between the focus ring 201 and the dielectric ring 202, and/or a thermally conductive layer is disposed between the dielectric ring 202 and the base 101 to improve the ability to conduct heat to the temperature of the focus ring 201. In other embodiments, the dielectric ring 202 may be disposed over other independently temperature-controllable support members to achieve independent temperature control of the focus ring 201 from the substrate 103.
In addition, an insulating window 130 is disposed above the reaction chamber, an inductive coil 140 is disposed above the insulating window, a high-frequency rf power source 145 applies an rf signal to the inductive coil 140, the inductive coil 140 generates an alternating magnetic field, and an alternating electric field is induced in the reaction chamber, thereby achieving plasma dissociation of the process gas entering the reaction chamber. In this embodiment, the process gas may be injected into the reaction chamber from the sidewall of the reaction chamber, or a gas injection port may be provided on the insulating window to accommodate the process gas. A bias RF power source is applied to the lower electrode assembly through a bias RF match for controlling the energy distribution of the plasma.
The utility model provides a plasma corrosion resistant lower electrode subassembly and plasma processing apparatus, through covering the protection ring on the weld line at the base, improve the dielectric capacity in edge ring subassembly and base clearance, avoid letting out the contact of plasma and protective layer unevenness department simultaneously, prevent that plasma from corroding base and accessory, the arc discharge's that lower electrode subassembly probably appears possibility has been reduced, and block the clearance below and take place the extension of arc discharge back to last, the effectual safe in utilization who guarantees lower electrode subassembly.
The utility model discloses a lower electrode subassembly is not restricted to the plasma processing apparatus who is applied to above-mentioned two kinds of embodiments, also can be suitable for in other plasma processing apparatus, and the no longer repeated description is here.
While the present invention has been described in detail with reference to the preferred embodiments thereof, it should be understood that the above description should not be taken as limiting the present invention. Numerous modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims.
Claims (14)
1. A bottom electrode assembly for carrying a substrate to be processed, comprising:
the base comprises a base body and a step part extending outwards from the base body, and a welding line is arranged on the base body;
an electrostatic chuck located above the pedestal;
an edge ring assembly disposed around the pedestal and/or electrostatic chuck with a gap therebetween;
the gap is provided with a first protection ring, and the first protection ring covers the welding line.
2. The lower electrode assembly according to claim 1, wherein the outer side of the base is provided with a protective layer.
3. The lower electrode assembly of claim 2, wherein the protective layer is a layer of aluminum oxide and/or yttrium oxide material, or a hard anodized layer.
4. The lower electrode assembly according to claim 1, wherein the stepped portion has a screw hole formed therein, and the first protective ring covers at least a portion of an edge of the screw hole.
5. The lower electrode assembly of claim 4, wherein the first protective ring covers a rim of the threaded hole located within the gap.
6. The lower electrode assembly of claim 1, wherein the gap comprises a first gap and a second gap, the first gap being located above the first protective ring, the second gap being located below the first gap, the second gap having a spacing greater than a spacing of the first gap.
7. The lower electrode assembly of claim 6, wherein a corner between the first and second voids is in contact with the first protective ring.
8. The lower electrode assembly of claim 1, further comprising a second guard ring disposed at an interface of the pedestal and the electrostatic chuck.
9. The lower electrode assembly of claim 8, wherein at least a portion of the second protective ring abuts the base body and the edge ring assembly.
10. The lower electrode assembly of claim 8, wherein a groove is provided where the first protective ring and/or the second protective ring contact the susceptor body and/or the edge ring assembly, the groove having an arc-shaped or frame-shaped cross-section.
11. The lower electrode assembly of claim 8, wherein the first protective ring and the second protective ring are of a plasma resistant material.
12. The lower electrode assembly of claim 8, wherein the first and second protective rings are polymeric materials.
13. The lower electrode assembly of claim 8, wherein the first and second protective rings are of a fluoroelastomer or perfluororubber family.
14. A plasma processing apparatus comprising a vacuum processing chamber, wherein the vacuum processing chamber comprises a lower electrode assembly according to any one of claims 1 to 13.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023070019.3U CN213583694U (en) | 2020-12-18 | 2020-12-18 | Lower electrode assembly and plasma processing device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202023070019.3U CN213583694U (en) | 2020-12-18 | 2020-12-18 | Lower electrode assembly and plasma processing device |
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| CN213583694U true CN213583694U (en) | 2021-06-29 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114649178A (en) * | 2020-12-18 | 2022-06-21 | 中微半导体设备(上海)股份有限公司 | Lower electrode assembly and plasma processing device |
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- 2020-12-18 CN CN202023070019.3U patent/CN213583694U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114649178A (en) * | 2020-12-18 | 2022-06-21 | 中微半导体设备(上海)股份有限公司 | Lower electrode assembly and plasma processing device |
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