CN111463094B - Atomic layer etching device and atomic layer etching method - Google Patents
Atomic layer etching device and atomic layer etching method Download PDFInfo
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- CN111463094B CN111463094B CN202010298307.XA CN202010298307A CN111463094B CN 111463094 B CN111463094 B CN 111463094B CN 202010298307 A CN202010298307 A CN 202010298307A CN 111463094 B CN111463094 B CN 111463094B
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- 238000005530 etching Methods 0.000 title claims abstract description 143
- 238000000034 method Methods 0.000 title claims abstract description 48
- 238000006243 chemical reaction Methods 0.000 claims abstract description 56
- 230000007246 mechanism Effects 0.000 claims abstract description 42
- 150000002500 ions Chemical class 0.000 claims abstract description 16
- 239000007789 gas Substances 0.000 claims description 127
- 230000003213 activating effect Effects 0.000 claims description 29
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 16
- 238000010926 purge Methods 0.000 claims description 15
- 229910052786 argon Inorganic materials 0.000 claims description 9
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 3
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 25
- 238000002955 isolation Methods 0.000 abstract description 9
- 230000009286 beneficial effect Effects 0.000 abstract description 8
- 210000002381 plasma Anatomy 0.000 description 48
- 235000012431 wafers Nutrition 0.000 description 22
- 230000004913 activation Effects 0.000 description 14
- 239000000460 chlorine Substances 0.000 description 10
- 238000001914 filtration Methods 0.000 description 10
- 229910052801 chlorine Inorganic materials 0.000 description 8
- 239000000376 reactant Substances 0.000 description 8
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 230000006698 induction Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
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- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
- H01J37/3053—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/16—Vessels; Containers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
- H01J37/3053—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching
- H01J37/3056—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching for evaporating or etching for microworking, e. g. etching of gratings or trimming of electrical components
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
- H01J37/32082—Radio frequency generated discharge
- H01J37/32091—Radio frequency generated discharge the radio frequency energy being capacitively coupled to the plasma
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- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32458—Vessel
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- H—ELECTRICITY
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- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32532—Electrodes
- H01J37/32568—Relative arrangement or disposition of electrodes; moving means
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- H—ELECTRICITY
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- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
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- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32798—Further details of plasma apparatus not provided for in groups H01J37/3244 - H01J37/32788; special provisions for cleaning or maintenance of the apparatus
- H01J37/32899—Multiple chambers, e.g. cluster tools
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
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Abstract
The invention provides atomic layer etching equipment and an atomic layer etching method, wherein the equipment comprises a reaction chamber, an upper electrode mechanism arranged at the top of the reaction chamber, a base arranged in the reaction chamber, and an intermediate electrode mechanism, wherein the intermediate electrode mechanism comprises an electrode plate assembly and an intermediate radio frequency power supply electrically connected with the electrode plate assembly, the electrode plate assembly is arranged in the reaction chamber and is positioned between the upper electrode mechanism and the base, and the reaction chamber is separated to form an upper subchamber and a lower subchamber; and the upper subchamber is provided with an upper air inlet, and the lower subchamber is provided with a lower air inlet; a plurality of filter holes are provided in the electrode plate assembly to communicate the upper sub-chamber with the lower sub-chamber and to reduce the energy of ions in the plasma in the upper sub-chamber as the plasma passes through the filter holes. The atomic layer etching equipment provided by the invention not only can improve the process uniformity, but also is beneficial to realizing isolation of the activated gas and the etching gas.
Description
Technical Field
The invention relates to the technical field of atomic layer etching, in particular to atomic layer etching equipment and an atomic layer etching method.
Background
The atomic layer etching (Atomic Layer Etching, ALE) process is a self-limiting reaction performed by a plurality of reaction steps in sequence, can achieve the control of atomic-level Characteristic Dimension (CD), has the advantages of low surface roughness, damage and the like, and has a great application prospect in sub-10nm nodes.
A typical ALE apparatus typically comprises a reaction chamber, a dielectric window disposed at the top of the reaction chamber, a planar induction coil located above the dielectric window, and a susceptor disposed in the reaction chamber. The plane induction coil is electrically connected with the upper radio frequency power supply; the base is electrically connected with a lower radio frequency power supply; the reaction chamber also has an inlet for the process gas. Taking a silicon etching process as an example, chlorine gas and argon gas are generally used as activating gas and etching gas respectively, and the activating step and the etching step are circularly and alternately performed until a target etching depth is reached.
In the above ALE apparatus, although the generation of plasma by the planar induction coil is advantageous in generating high-density plasma, the magnetic field intensity generated by the coil is unevenly distributed in the radial direction of the chamber, particularly in the M-shape, resulting in uneven distribution of Cl or Ar plasma generated in the chamber in the radial direction of the chamber, thereby affecting the activation uniformity and etching uniformity. In addition, although the reaction chamber is purged between the activation step and the etching step to remove the residual gas and the reactant of the previous step in the reaction chamber, the purge step cannot completely remove the residual gas and the reactant, so that it is difficult to achieve isolation of the activation gas and the etching gas.
Disclosure of Invention
The invention aims at solving at least one of the technical problems in the prior art, and provides atomic layer etching equipment and an atomic layer etching method, which can improve the process uniformity and are beneficial to realizing isolation of activated gas and etching gas.
In order to achieve the above object, the present invention provides an atomic layer etching apparatus, which comprises a reaction chamber, an upper electrode mechanism arranged at the top of the reaction chamber, a base arranged in the reaction chamber, and an intermediate electrode mechanism, wherein the intermediate electrode mechanism comprises an electrode plate assembly and an intermediate radio frequency power supply electrically connected with the electrode plate assembly, the electrode plate assembly is arranged in the reaction chamber, is positioned between the upper electrode mechanism and the base, and separates the reaction chamber to form an upper sub-chamber and a lower sub-chamber; and, the upper subchamber has an upper air inlet and the lower subchamber has a lower air inlet;
a plurality of filter holes are provided in the electrode plate assembly to communicate the upper and lower subchambers and to reduce the energy of ions in the plasma in the upper subchamber as it passes through the filter holes.
Optionally, the electrode plate assembly includes a conductive plate and an annular dielectric plate surrounding the conductive plate and fixedly connected with the conductive plate, wherein the annular dielectric plate is fixedly connected with a side wall of the reaction chamber and insulates the conductive plate and the side wall of the reaction chamber from each other; the conductive plate is electrically connected with the intermediate radio frequency power supply; and each of the filter holes is a through hole penetrating through the conductive plate in a thickness direction of the conductive plate.
Optionally, a dielectric layer is disposed on the outer surface of the conductive plate, and the dielectric layer at least covers the upper surface and the lower surface of the conductive plate.
Optionally, dielectric plates are respectively disposed on the upper surface and the lower surface of the conductive plate.
Optionally, the thickness of the electrode plate assembly ranges from 5mm to 20mm.
Optionally, the through hole is a round hole, and the diameter of the round hole ranges from 3mm to 10mm.
Optionally, the atomic layer etching device further includes a dielectric window, where the dielectric window is disposed at the top of the reaction chamber; the upper electrode mechanism comprises an inductance coil and an upper radio frequency power supply electrically connected with the inductance coil, wherein the inductance coil is arranged above the dielectric window.
Optionally, the upper electrode mechanism includes an upper electrode plate disposed in the reaction chamber and above the base, and an upper rf power supply electrically connected to the upper electrode plate.
Optionally, the atomic layer etching apparatus further includes a lower radio frequency power supply electrically connected to the susceptor.
As another technical scheme, the invention also provides an atomic layer etching method, which adopts the atomic layer etching equipment provided by the invention to carry out etching, and comprises the following steps:
and S100, introducing etching gas into the upper subchamber through the upper air inlet, starting the upper electrode mechanism and the middle electrode mechanism to excite the etching gas to form plasma, and starting a lower radio frequency power supply electrically connected with the base so as to enable the plasma to etch the surface of the wafer.
Optionally, the step S100 further includes:
s101, introducing an activating gas into the lower subchamber through the lower gas inlet, and starting the intermediate electrode mechanism to excite the activating gas to form plasma so as to form an activating layer on the surface of a wafer;
s102, introducing a purge gas into the reaction chamber to purge the reaction chamber;
s103, introducing etching gas into the upper subchamber through the upper air inlet, starting the upper electrode mechanism and the middle electrode mechanism to excite the etching gas to form plasma, and starting the lower radio frequency power supply to enable the plasma to etch the surface of the wafer;
s104, introducing a purge gas into the reaction chamber to purge the reaction chamber;
and repeating the step S101 to the step S104 until reaching the target etching depth.
Optionally, in step S101, while the activating gas is introduced into the lower subchamber through the lower gas inlet, the etching gas is introduced into the upper subchamber through the upper gas inlet, and the upper electrode mechanism is started to excite the etching gas to form plasma.
Optionally, in the step S101, the chamber pressures in the upper sub-chamber and the lower sub-chamber are controlled respectively, so that the chamber pressure of the upper sub-chamber is greater than the chamber pressure of the lower sub-chamber.
Optionally, in step S103, while etching gas is being introduced into the upper sub-chamber through the upper gas inlet, the etching gas is introduced into the lower sub-chamber through the lower gas inlet, and the flow rates of the etching gas introduced into the upper sub-chamber and the lower sub-chamber are controlled so that the flow rate of the etching gas introduced into the upper sub-chamber is greater than the flow rate of the etching gas introduced into the lower sub-chamber.
Optionally, the activating gas comprises chlorine gas; the etching gas includes argon.
The invention has the beneficial effects that:
the atomic layer etching equipment provided by the invention can generate capacitively coupled plasma by utilizing the electrode plate component of the intermediate electrode mechanism, and is beneficial to improving the uniformity of plasma density distribution, so that the activation uniformity and the etching uniformity can be improved, and the process uniformity is further improved. Moreover, the electrode plate assembly is utilized to divide the reaction chamber into an upper subchamber and a lower subchamber, which is beneficial to realizing the isolation of the activating gas and the etching gas.
According to the atomic layer etching method, the atomic layer etching equipment provided by the invention is used for etching, so that the process uniformity can be improved, and isolation of two reactions of the activated gas and the etching gas can be realized.
Drawings
FIG. 1 is a cross-sectional view of an atomic layer etching apparatus according to an embodiment of the present invention;
FIG. 2 is a top view of an electrode plate assembly employed in an embodiment of the present invention;
FIG. 3 is a block flow diagram of an atomic layer etching method according to an embodiment of the present invention;
FIG. 4 is a block diagram of another embodiment of an atomic layer etching method according to the present invention;
fig. 5 is a sequence of steps of the atomic layer etching method of fig. 4.
Detailed Description
In order to enable those skilled in the art to better understand the technical scheme of the present invention, the atomic layer etching apparatus and the atomic layer etching method provided by the present invention are described in detail below with reference to the accompanying drawings.
Referring to fig. 1, an atomic layer etching apparatus provided in an embodiment of the present invention includes a reaction chamber 1, an upper electrode mechanism 2 and a dielectric window 3 disposed at the top of the reaction chamber 1, a base 4 disposed in the reaction chamber 1, and an intermediate electrode mechanism.
Specifically, in the present embodiment, the upper electrode mechanism 2 includes an inductance coil 21 and an upper radio frequency power supply 22 electrically connected to the inductance coil 21, wherein the inductance coil 21 is disposed above the dielectric window 3. The upper rf power supply 22 is turned on to apply rf power to the inductor 21, which is fed into the reaction chamber 1 through the dielectric window 3 to excite the process gas in the chamber to form plasma.
In this embodiment, the inductive coil 21 can be used to generate plasma with higher density in an inductive coupling manner, so as to be beneficial to improving the etching rate and improving the process efficiency. Alternatively, the inductor 21 is a planar coil, such as a planar spiral coil. Further, the inductance coil 21 may be composed of an inner coil and an outer coil which are concentric and have different inner diameters, so as to realize the zonal control of the plasma density distribution in the radial direction of the chamber. Of course, in practical application, the inductance coil 21 may be a single coil or may be composed of three or more coils.
It should be noted that, in practical application, according to different process requirements, the upper electrode mechanism may also use an upper electrode plate instead of the above-mentioned inductor 21, specifically, the upper electrode plate is disposed in the reaction chamber 1 and is located above the base 4, and an upper radio frequency power supply is electrically connected with the upper electrode plate. The upper electrode plate can be used for generating more uniform plasmas in a capacitive coupling mode, so that the process uniformity is improved.
The susceptor 4 is used for carrying wafers. The susceptor 4 is, for example, an electrostatic chuck.
In this embodiment, the atomic layer etching apparatus further includes a lower rf power supply 5 electrically connected to the susceptor 4 for applying rf power to the susceptor 4 so as to generate a bias voltage capable of attracting plasma on the wafer surface on the susceptor 4. Of course, in practical application, the rf power supply 5 may be selected to be not configured according to different process requirements.
The intermediate electrode mechanism comprises an electrode plate assembly 6 and an intermediate radio frequency power supply 63 electrically connected to the electrode plate assembly 6, wherein the electrode plate assembly 6 is arranged in the reaction chamber 1 and between the upper electrode mechanism 2 and the base 4, and in this embodiment, the electrode plate assembly 6 is arranged between the dielectric window 3 and the base 4 and is respectively arranged at intervals from the two. And, the electrode plate assembly 6 partitions the reaction chamber 1 to form an upper sub-chamber 11 and a lower sub-chamber 12. The upper sub-chamber 11 has an upper gas inlet 111, and the lower sub-chamber 12 has a lower gas inlet 121, all for introducing process gas into the chamber. Also, a plurality of filtering holes 611 are provided in the electrode plate assembly 6 to communicate the upper sub-chamber 11 with the lower sub-chamber 12. In addition, when the plasma formed in the upper sub-chamber 11 passes through the filtering holes 611, the filtering holes 611 can reduce the energy of ions in the plasma, for example, the energy of high-energy Ar ions in Ar plasma generated by argon gas, so that damage to the wafer surface due to the high-energy Ar ions can be prevented.
In practice, the reduction of the energy of ions in the plasma can be achieved by setting parameters such as the size, shape, etc. of the filter holes 611 and the thickness of the electrode plate assembly 6.
In this embodiment, referring to fig. 1 and 2 together, the electrode plate assembly 6 includes a conductive plate 61 and an annular dielectric plate 62 surrounding the conductive plate 61 and fixedly connected to the conductive plate 61, wherein the annular dielectric plate 62 is fixedly connected to the sidewall of the reaction chamber 1, so that the conductive plate 61 can be fixed to the sidewall of the reaction chamber 1. The annular dielectric plate 62 and the conductive plate 61 together realize a separation of the reaction chamber 1 into an upper sub-chamber 11 and a lower sub-chamber 12, while the annular dielectric plate 62 enables the conductive plate 61 to be insulated from the side walls of the reaction chamber 1. Alternatively, the annular dielectric plate 62 is fabricated from a dielectric material such as quartz, ceramic, or the like.
As shown in fig. 2, the conductive plate 61 is electrically connected to the intermediate radio frequency power source 63, and a through hole penetrating the conductive plate 61 in the thickness direction of the conductive plate 61 is provided in the conductive plate 61, serving as the above-described filtering hole 611. Alternatively, the through holes in the conductive plate 61 are uniformly distributed with respect to the plane of the conductive plate 61.
When the intermediate rf power supply 63 is turned on, it applies rf power to the conductive plate 61, so that the conductive plate 61 is capacitively coupled to the susceptor 4, thereby forming a capacitively coupled plasma with a more uniform distribution in the lower sub-chamber 12. Taking the example of the silicon etching process by using the atomic layer etching apparatus provided in this embodiment, chlorine and argon are generally used as the activating gas and the etching gas respectively,the etching process is cycled through alternating activation steps and etching steps until a target etching depth is reached. During the activation step, an activating gas, such as chlorine (Cl), is introduced into the lower subchamber 12 through the lower gas inlet 121 2 ) And the intermediate rf power supply 63 is turned on to apply rf power to the conductive plate 61 to excite the activated gas in the lower subchamber 12 to form a plasma. Since the phases of the conductive plate 61 at different positions in the radial (or angular) direction of the chamber are equal, the density and ion energy of the plasma formed between the conductive plate 61 and the susceptor 4 can be uniformly distributed in the radial (or angular) direction of the chamber, so that the activation uniformity can be improved.
In the etching process, etching gas such as argon (Ar) is introduced into the upper sub-chamber 11 through the upper gas inlet 111, and the upper rf power supply 22, the middle rf power supply 63 and the lower rf power supply 5 are turned on to form Ar plasmas in the upper sub-chamber 11 and the lower sub-chamber 12 respectively, wherein the Ar plasmas in the upper sub-chamber 11 reduce the energy of high-energy Ar ions through the filtering holes 611, so that the damage of the high-energy Ar ions to the wafer surface can be avoided; meanwhile, electrons and high-energy particles in the plasma can enter the lower subchamber 12 through the filtering holes 611 and bombard the surface of the wafer under the effect of the radio frequency power loaded on the base 4 by the lower radio frequency power supply 5, so that the etching of the wafer is realized. In this process, since the phases of the conductive plate 61 at different positions in the chamber radial direction (or angular direction) are equal, the density and ion energy of the Ar plasma formed between the conductive plate 61 and the susceptor 4 can be uniformly distributed in the chamber radial direction (or angular direction), so that etching uniformity can be improved.
In addition, in the etching process, since the activating step is to introduce the activating gas into the lower sub-chamber 12 through the lower gas inlet 121, the redundant activating gas and reactant in the lower sub-chamber 12 can be directly discharged out of the chamber through the gas extraction opening 7 at the bottom of the chamber, so as to be helpful for removing the residual activating gas and reactant in the subsequent purging step; in addition, the etching step is to introduce etching gas into the upper sub-chamber 11 through the upper gas inlet 111, so that the atomic layer etching device provided by the embodiment of the invention is more beneficial to realizing isolation between the activation gas and the etching gas.
Optionally, dielectric layers (shown in the drawings) are provided on the outer surface of the conductive plate 61, and the dielectric layers are provided on the upper and lower surfaces of the conductive plate 61 to perform an insulating function, and at the same time, to protect the conductive plate 61 from plasma erosion. Of course, in practical application, dielectric plates may be used instead of the dielectric layers on the upper and lower surfaces of the conductive plate 61.
In addition, taking the atomic layer etching apparatus provided in this embodiment for performing the silicon etching process, using chlorine and argon as the activating gas and the etching gas, respectively, for example, the filter holes 611 can reduce high-energy Ar in the Ar plasma in the etching step by setting parameters such as the size, shape, etc. of the filter holes 611 and the thickness of the electrode plate assembly 6 (the total thickness of the conductive plate 61 and the dielectric layer if the dielectric layer is provided) + Is a function of the energy of the (c). Alternatively, the thickness of the electrode plate assembly 6 may be in the range of 5mm to 20mm; if the filtering holes 611 are round holes, the diameter of the round holes is 3mm-10mm.
In summary, the atomic layer etching apparatus provided by the embodiment of the invention can generate the capacitively coupled plasma by using the electrode plate component of the intermediate electrode mechanism, which is helpful to improve the uniformity of plasma density distribution, so as to improve the activation uniformity and the etching uniformity, and further improve the process uniformity. Moreover, the electrode plate assembly is utilized to divide the reaction chamber into an upper subchamber and a lower subchamber, which is beneficial to isolating the activating gas from the etching gas.
As another technical solution, an embodiment of the present invention further provides an atomic layer etching method, which uses the atomic layer etching apparatus provided by the embodiment of the present invention to perform etching. Referring to fig. 1 and 3 together, the atomic layer etching method provided by the embodiment of the invention includes the following steps:
and S100, introducing etching gas into the upper subchamber 11 through the upper gas inlet 111, starting the upper radio frequency power supply 22 of the upper electrode mechanism 2 and the middle radio frequency power supply 63 of the middle electrode mechanism, exciting the etching gas to form plasma, and starting the lower radio frequency power supply 5 electrically connected with the base 4 so as to etch the surface of the wafer by the plasma.
In the process of performing step S100, etching gas, such as argon (Ar), is introduced into the upper sub-chamber 11 through the upper gas inlet 111, and the upper rf power supply 22 and the intermediate rf power supply 63 are turned on to form Ar plasma in the upper sub-chamber 11, and the Ar plasma in the upper sub-chamber 11 reduces the energy of high-energy Ar ions through the filtering holes 611, so that damage to the wafer surface caused by the high-energy Ar ions can be avoided; meanwhile, electrons and high-energy particles in the plasma can enter the lower subchamber 12 through the filtering holes 611 and bombard the surface of the wafer under the effect of the radio frequency power loaded on the base 4 by the lower radio frequency power supply 5, so that the etching of the wafer is realized. In this process, since the phases of the conductive plate 61 at different positions in the chamber radial direction (or angular direction) are equal, the density and ion energy of the Ar plasma formed between the conductive plate 61 and the susceptor 4 can be uniformly distributed in the chamber radial direction (or angular direction), so that etching uniformity can be improved.
Referring to fig. 1, 4 and 5, in order to etch the wafer more easily, the step S100 further includes:
s101, introducing an activating gas into the lower subchamber 12 through the lower gas inlet 121, and starting the intermediate radio frequency power supply 63 of the intermediate electrode mechanism to excite the activating gas to form plasma so as to form an activating layer on the surface of the wafer.
The activation layer facilitates easier etching of the wafer in subsequent etching steps.
When the intermediate rf power supply 63 is turned on, it applies rf power to the conductive plate 61, so that the conductive plate 61 is capacitively coupled to the susceptor 4, and phases of the conductive plate 61 at different positions in the radial direction (or angular direction) of the chamber are equal, which enables the density and ion energy of the plasma formed between the conductive plate 61 and the susceptor 4 to be uniformly distributed in the radial direction (or angular direction) of the chamber, thereby improving the activation uniformity.
Taking the example of etching a silicon wafer by using the atomic layer etching method provided in this embodiment, a silicon wafer is etched by using the atomic layer etching method as a general methodChlorine (Cl) 2 ) As an activating gas. In the process of step S101, chlorine is introduced into the lower subchamber 12 through the lower air inlet 121, the intermediate rf power supply 63 is turned on, and rf power is applied to the conductive plate 61 to excite the chlorine in the lower subchamber 12 to form plasma, and Al radicals in the Al plasma activate the wafer surface material.
Since the activating gas is introduced into the lower sub-chamber 12 through the lower gas inlet 121 in step S101, the excessive activating gas and reactant in the lower sub-chamber 12 can be directly discharged out of the chamber through the gas extraction opening 7 at the bottom of the chamber, so as to facilitate the removal of the residual activating gas and reactant in the subsequent step S2 for purging.
Optionally, as shown in fig. 5, in step S101, while the activation gas is introduced into the lower sub-chamber 12 through the lower gas inlet 121, the etching gas (for example, ar) is introduced into the upper sub-chamber 11 through the upper gas inlet 111, and the upper rf power supply 22 of the upper electrode mechanism is turned on to excite the etching gas to form plasma. In this case, although the Ar plasma is formed in the upper sub-chamber 11, since the energy of high-energy Ar ions in the Ar plasma is reduced by the filtering holes 611, cl plasma in the lower sub-chamber 12 is mainly applied to the wafer surface and deposited to form an activation layer. Meanwhile, etching gas is introduced into the upper sub-chamber 11 through the upper gas inlet 111, so that the upward diffusion of chlorine in the lower sub-chamber 12 can be further avoided, and the isolation of the activation gas from the upper sub-chamber 11 can be ensured.
Optionally, in step S101, the chamber pressures in the upper sub-chamber 11 and the lower sub-chamber 12 are controlled so that the chamber pressure of the upper sub-chamber 11 is greater than the chamber pressure of the lower sub-chamber 12, which can further avoid upward diffusion of chlorine in the lower sub-chamber 12, and thus can ensure isolation of the activated gas from the upper sub-chamber 11.
S102, introducing a purge gas into the reaction chamber 1 to purge the reaction chamber 1.
Step S102 is for removing the activated gas and the reactant remaining in the chamber in step S101.
And S103, introducing etching gas into the upper subchamber 11 through the upper air inlet 111, starting the upper radio frequency power supply 22 of the upper electrode mechanism 2 and the middle radio frequency power supply 63 of the middle electrode mechanism, exciting the etching gas to form plasma, and starting the lower radio frequency power supply 5 so that the plasma bombards the surface of the wafer under the action of radio frequency power loaded on the base 4 by the lower radio frequency power supply 5, thereby realizing etching of the surface of the wafer.
Optionally, in step S103, while etching gas is being introduced into the upper sub-chamber 11 through the upper gas inlet 111, etching gas is introduced into the lower sub-chamber 12 through the lower gas inlet 121, and the flow rates of the etching gas introduced into the upper sub-chamber 11 and the lower sub-chamber 12 are controlled so that the flow rate of the etching gas introduced into the upper sub-chamber 11 is greater than the flow rate of the etching gas introduced into the lower sub-chamber 12. This ensures that enough electrons and energetic particles can pass through the filter holes 611 into the lower subchamber 12 to meet process requirements.
And S104, introducing a purge gas into the reaction chamber 1 to purge the reaction chamber 1.
Step S104 is for removing the etching gas and the reactant remaining in the chamber in step S103.
The above steps S101 to S104 are repeated until the target etching depth is reached.
According to the atomic layer etching method provided by the embodiment of the invention, the atomic layer etching equipment provided by the embodiment of the invention is used for etching, so that the process uniformity can be improved, and isolation of the activated gas and the etching gas can be realized.
It is to be understood that the above embodiments are merely illustrative of the application of the principles of the present invention, but not in limitation thereof. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the invention, and are also considered to be within the scope of the invention.
Claims (15)
1. An atomic layer etching device comprises a reaction chamber, an upper electrode mechanism arranged at the top of the reaction chamber and a base arranged in the reaction chamber, and is characterized by further comprising an intermediate electrode mechanism, wherein the intermediate electrode mechanism comprises an electrode plate assembly and an intermediate radio frequency power supply electrically connected with the electrode plate assembly, the electrode plate assembly is arranged in the reaction chamber, is positioned between the upper electrode mechanism and the base and separates the reaction chamber to form an upper subchamber and a lower subchamber; the upper subchamber is provided with an upper gas inlet for introducing etching gas, and the lower subchamber is provided with a lower gas inlet for introducing activating gas;
a plurality of filter holes are provided in the electrode plate assembly to communicate the upper and lower subchambers and to reduce the energy of ions in the plasma in the upper subchamber as it passes through the filter holes.
2. The atomic layer etching apparatus according to claim 1, wherein the electrode plate assembly comprises a conductive plate and an annular dielectric plate surrounding the conductive plate and fixedly connected to the conductive plate, wherein the annular dielectric plate is fixedly connected to and insulates the conductive plate from a sidewall of the reaction chamber; the conductive plate is electrically connected with the intermediate radio frequency power supply; and each of the filter holes is a through hole penetrating through the conductive plate in a thickness direction of the conductive plate.
3. The atomic layer etching apparatus according to claim 2, wherein a dielectric layer is provided on an outer surface of the conductive plate, the dielectric layer covering at least an upper surface and a lower surface of the conductive plate.
4. The atomic layer etching apparatus according to claim 2, wherein dielectric plates are provided on upper and lower surfaces of the conductive plate, respectively.
5. The atomic layer etching apparatus according to any one of claims 2 to 4, wherein the thickness of the electrode plate assembly has a value ranging from 5mm to 20mm.
6. The atomic layer etching apparatus according to any one of claims 2 to 4, wherein the through hole is a circular hole, and the diameter of the circular hole has a value ranging from 3mm to 10mm.
7. The atomic layer etching apparatus according to claim 1, further comprising a dielectric window disposed on top of the reaction chamber; the upper electrode mechanism comprises an inductance coil and an upper radio frequency power supply electrically connected with the inductance coil, wherein the inductance coil is arranged above the dielectric window.
8. The atomic layer etching apparatus according to claim 1, wherein the upper electrode mechanism comprises an upper electrode plate disposed in the reaction chamber and located above the susceptor, and an upper radio frequency power supply electrically connected to the upper electrode plate.
9. The atomic layer etching apparatus according to claim 1, further comprising a lower radio frequency power supply electrically connected to the pedestal.
10. An atomic layer etching method, characterized in that the atomic layer etching apparatus according to any one of claims 1 to 9 is used for etching, the atomic layer etching method comprising the steps of:
and S100, introducing etching gas into the upper subchamber through the upper air inlet, starting the upper electrode mechanism and the middle electrode mechanism to excite the etching gas to form plasma, and starting a lower radio frequency power supply electrically connected with the base so as to enable the plasma to etch the surface of the wafer.
11. The atomic layer etching method according to claim 10, wherein the step S100 further comprises:
s101, introducing an activating gas into the lower subchamber through the lower gas inlet, and starting the intermediate electrode mechanism to excite the activating gas to form plasma so as to form an activating layer on the surface of a wafer;
s102, introducing a purge gas into the reaction chamber to purge the reaction chamber;
s103, introducing etching gas into the upper subchamber through the upper air inlet, starting the upper electrode mechanism and the middle electrode mechanism to excite the etching gas to form plasma, and starting the lower radio frequency power supply to enable the plasma to etch the surface of the wafer;
s104, introducing a purge gas into the reaction chamber to purge the reaction chamber;
and repeating the step S101 to the step S104 until reaching the target etching depth.
12. The atomic layer etching method according to claim 11, wherein in the step S101, the etching gas is introduced into the upper sub-chamber through the upper gas inlet while the activating gas is introduced into the lower sub-chamber through the lower gas inlet, and the upper electrode mechanism is turned on to excite the etching gas to form plasma.
13. The atomic layer etching method according to claim 12, wherein in the step S101, the chamber pressures in the upper and lower sub-chambers are controlled so that the chamber pressure of the upper sub-chamber is greater than the chamber pressure of the lower sub-chamber, respectively.
14. The atomic layer etching method according to claim 11, wherein in the step S103, etching gas is introduced into the upper sub-chamber through the upper gas inlet while etching gas is introduced into the lower sub-chamber through the lower gas inlet, and the flow rates of the etching gas introduced into the upper and lower sub-chambers, respectively, are controlled so that the flow rate of the etching gas introduced into the upper sub-chamber is greater than the flow rate of the etching gas introduced into the lower sub-chamber.
15. The atomic layer etching method according to claim 11, wherein the activating gas includes chlorine gas; the etching gas includes argon.
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| CN107636793A (en) * | 2015-03-17 | 2018-01-26 | 应用材料公司 | Ion pair ion plasma atomic layer etch technique and reactor |
| CN109698109A (en) * | 2017-10-23 | 2019-04-30 | 三星电子株式会社 | Plasma process system, electron beam generator and method, semi-conductor device manufacturing method |
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| CN107636793A (en) * | 2015-03-17 | 2018-01-26 | 应用材料公司 | Ion pair ion plasma atomic layer etch technique and reactor |
| CN109698109A (en) * | 2017-10-23 | 2019-04-30 | 三星电子株式会社 | Plasma process system, electron beam generator and method, semi-conductor device manufacturing method |
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