US20150243485A1 - Device for Treating an Object with Plasma - Google Patents

Device for Treating an Object with Plasma Download PDF

Info

Publication number
US20150243485A1
US20150243485A1 US14/415,976 US201314415976A US2015243485A1 US 20150243485 A1 US20150243485 A1 US 20150243485A1 US 201314415976 A US201314415976 A US 201314415976A US 2015243485 A1 US2015243485 A1 US 2015243485A1
Authority
US
United States
Prior art keywords
plasma
subassembly
gas
subassemblies
treating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US14/415,976
Other languages
English (en)
Inventor
Gilles Baujon
Emmanuel Guidotti
Yannick Pilloux
Patrick Rabinzohn
Julien Richard
Marc Segers
Vincent Girault
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plasma Therm LLC
Original Assignee
NANOPLAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NANOPLAS filed Critical NANOPLAS
Publication of US20150243485A1 publication Critical patent/US20150243485A1/en
Assigned to NANOPLAS reassignment NANOPLAS CORRECTIVE ASSIGNMENT TO CORRECT THE INCORRECT APPLICATION NO. 14/516976 TO READ THE CORRECT APPLICATION NO. 14/415976 PREVIOUSLY RECORDED ON REEL 035314 FRAME 0427. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT. Assignors: RABINZOHN, PATRICK, PILLOUX, Yannick, GUIDOTTI, EMMANUEL, SEGERS, MARC, GIRAULT, VINCENT, RICHARD, Julien, BAUJON, Gilles
Assigned to PLASMA-THERM, LLC reassignment PLASMA-THERM, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NANOPLAS
Abandoned legal-status Critical Current

Links

Images

Classifications

    • 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
    • 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
    • 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
    • H01J37/32357—Generation remote from the workpiece, e.g. down-stream
    • 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
    • H01J37/32366—Localised processing
    • 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
    • H01J37/32403—Treating multiple sides of workpieces, e.g. 3D workpieces
    • 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
    • H01J37/32431—Constructional details of the reactor
    • H01J37/3244—Gas supply means
    • H01J37/32449—Gas control, e.g. control of the gas flow
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
    • H01J2237/32—Processing objects by plasma generation
    • H01J2237/33—Processing objects by plasma generation characterised by the type of processing
    • H01J2237/334—Etching
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Definitions

  • the invention concerns the domain of plasma surface processing.
  • plasma surface processing is understood, in the sense of the present invention, different types of applications.
  • Applications can notably be cited consisting of the removal (or etching) of materials (and in particular materials such as photosensitive resins, metals, dielectrics or again semiconductors, etc.), the etching of structures such as holes or trenches in a silicon substrate or a layer comprised of metals, dielectrics or other substances, typically following a surface pattern printed in a photosensitive resin by photolithography, or again applications consisting of the removal of sacrificial layers.
  • a plasma is a partially ionized gas containing electrically charged species (ions and electrons) as well as electrically neutral but very chemically active species, free radicals: these are atoms and molecules in an electronically “excited” state but not having lost an electron.
  • electrically charged species ions and electrons
  • free radicals these are atoms and molecules in an electronically “excited” state but not having lost an electron.
  • micro-wave plasmas At the current time, there exist two dominant types of plasma technology for the surface processing of semi-conductors: micro-wave plasmas and inductively coupled plasmas.
  • micro-wave plasmas At the current time, there exist two dominant types of plasma technology for the surface processing of semi-conductors.
  • inductively coupled plasmas Each of the present technologies presents advantages and inconveniences.
  • micro-wave plasmas come from their ability to generate a high density of active chemical species (greater than 1017 cm-3).
  • This technology presents numerous inconveniences, however, such as the complexity of the plasma source and the non-uniformity of the processing.
  • the plasma source necessitates the vertical assembly of numerous parts (wave-guide, magnetron, etc.), that generates a significant bulk and renders it unreliable.
  • the plasma source is positioned upstream (with respect to the gas flow) and in the centre of a processing chamber, and this provides insufficient uniformity of the density of active plasma species, and therefore the processing of the substrate (positioned in the processing chamber), between the centre of the chamber (where the density of active species is very high) and its edge (where the density of active species is very low).
  • this type of plasma source presents the inconvenience of requiring very high electrical power, as well as very high gas flow-rates. All these inconveniences make this plasma process expensive, difficult to make reliable and difficult to control.
  • ICPs Inductively Coupled Plasmas or ICPs are easier to implement than micro-wave plasmas: the technology is simpler, less expensive and more easily controllable than micro-wave technology.
  • the principal inconvenience of this technology comes from the low density of chemically active species (about 10 15 cm ⁇ 3 ) thus obtained.
  • ICP plasmas suffer from the problem of non-uniformity in the density of active species between the centre of the chamber (where the density of active species is higher) and its edge (where the density of active species is lower), that makes the surface processing non-uniform. Processing speeds required by users impose the use of high power RF generators that are very costly and which lead to the heating of the gases used.
  • the plasma generated by the ICP sources can induce significant ionic bombardment of the substrates (for example semi-conductor wafers) whether voluntarily (RIE mode (reactive ion etching)) or not.
  • substrates for example semi-conductor wafers
  • RIE mode reactive ion etching
  • ICP and micro-wave sources attain a rate of dissociation of the gas that does not exceed 30%, which causes considerable dilution of the active species generated and very high consumption of gas. They are used in a unitary fashion: a single source is used per processing chamber and the size of the source is proportional to the volume treated. All of this imposes the implementation of voluminous sources that operate at high power, creating undesirable thermal effects on the substrates and significantly increasing the cost of these systems. Amongst these two types of sources, micro-wave plasmas are the most dense in terms of chemically active species but control of the process is difficult.
  • plasmas contain, other than free radicals that are electrically neutral, ions, electrons and UV radiation in the form of energetic photons that damage semi-conductor devices. The latter become more and more sensitive to this damage with miniaturization on the nanometre scale.
  • the presence of metal on the substrate can produce the risk of coupling with the micro-waves and very high heating that damages the components. This is the case of ultra-sensitive structures of micro-electro-mechanical systems (also designated by the acronym MEMS), as well as three-dimensional assemblies and interconnections that will be implemented in future generations of semi-conductors.
  • MEMS micro-electro-mechanical systems
  • a person skilled in the art knows plasma processing systems using a plurality of plasma sources, such as e.g. that described in the American patent application US 2005/0178746.
  • the system aims to improve the uniformity of the plasma processing by putting in parallel a plurality of plasma sources emitting the same chemically homogeneous plasma.
  • the present invention has therefore the subject matter of supplying a system for the plasma processing of an object and a process implementing such a device that will remedy these inconveniences.
  • the applicant has developed a system of plasma processing comprising a processing vacuum chamber and a plurality of plasma sources configured in independent subassemblies each generating a chemically different plasma.
  • the present invention has as subject matter a system for plasma processing of an object, said system comprising:
  • a processing vacuum chamber comprising a support on which the object to be processed is placed;
  • each subassembly comprising at least one plasma source allowing a plasma to be generated, each plasma source of a subassembly being supplied independently by radiofrequency power Pi and by a flow-rate ni of gas i.
  • the plasma generated by a subassembly is a partially ionized gas or gas mixture of different chemical nature from the plasma generated by the other subassembly or subassemblies.
  • each plasma source of a subassembly comprises:
  • a discharge chamber in a material inert to the plasma e.g. in the form of a tube;
  • a control device controls each of the subassemblies depending upon a specific configuration by application of radiofrequency power Pi and/or a flow-rate of gas ni, specific to each subassembly.
  • each subassembly comprises a gas inlet specific to the subassembly connected to the gas inlet of each plasma source of the subassembly.
  • each subassembly comprises a conductor element connected to the coupling device of each plasma source of the subassembly.
  • the subassemblies are arranged as concentric rings.
  • the subassemblies are arranged in parallel.
  • each plasma source comprises at least two discharge chambers in series.
  • the present invention also has the subject matter of a selective plasma processing method for processing a composite object comprising at least two different materials A and B, said process implementing a processing system according to the invention and comprising the following steps:
  • composite object it is understood, as defined by the present invention, an assembly of materials of very different nature, being able notably to take the form of a stack of thin films.
  • semiconductor-devices and in particular, silicon wafers comprising transistor structures and materials and other constituting elements of integrated circuits overlapped by one or a plurality of silicon oxide SiO2 layers overlapped by silicon nitride Si3N4, can be cited.
  • the steps of generation of plasma are repeated alternately, or with a partial or total overlap, and preferably with a partial overlap of steps of at most 25%.
  • the process according to the invention may consist of an etching treatment of the composite object, said composite object comprising at least two layers of different materials A and B, the layer of material A overlapping at least partially the layer of material B, said process comprising;
  • the processing using the first plasma of at least a first zone of the object comprising, on the surface, the material B, said processing using the first plasma consisting of a step of passivation or activation of material B, and
  • processing using the second plasma of at least a second zone of the object comprising, on the surface, the material A said processing using the second plasma consisting of a partial or total removal of material A, that can lead to the formation of a zone comprising the material B on the surface when the removal of the material A is total,
  • said process able to start either with a step of passivation or activation using the first plasma, or with a step of removal using the second plasma.
  • spacers (more particularly the thinning or removal of spacers), STI (“Shallow Trench Isolation”) structures (more particularly the total or partial removal “pull back” of the STI mask), transistors and advanced CMOS circuits (processors, memories) comprising layers of silicon nitride Si 3 N 4 (material A) on layers of silicon oxide SiO 2 (material B) can be cited, the silicon nitride often being a sacrificial material.
  • This embodiment of the process of the invention presents the major advantage of allying high selectivity with a high etching speed.
  • Selectivity is understood in the present invention to be the ratio of the speed of etching of the target material (material A, e.g. Si 3 N 4 ) to the speed of etching of another exposed material or material that can be exposed during the processing (here the material B, for example SiO 2 ), that ideally should not be etched.
  • material A e.g. Si 3 N 4
  • material B for example SiO 2
  • the fabrication of advanced CMOS circuits necessitates the removal of silicon nitride Si3N4 with very high selectivity, in particular compared to SiO2 and/or Si: the removal of Si3N4 must not damage the other materials.
  • the two processes used to perform this step of the removal of silicon nitride are on the one hand “wet” processes using phosphoric acid, and on the other hand, “dry” plasma processes with a fluorocarbon plasma containing a gas mixture CxFyHz/O2/H2/N2. These current processes do not allow a very high selectivity in the removal of silicon nitride to be achieved as it is typically only 50.
  • the fabrication of an Si3N4 spacer is done by directional etching of the previously deposited Si3N4 layer.
  • the principal difficulty of current etching processes resides in obtaining a spacer with a very specific shape, without consuming the silicon substrate.
  • the solution proposed in this article for obtaining this objective consists in modulating the plasma conditions (“time modulation of plasma parameters”).
  • sync pulsing is a technique consisting of switching on/off the power of the RF source and the RF power of the substrate carrier with a period of about 100 ⁇ s.
  • the etching process according to the invention resolves the inconveniences of the prior art and allows the allying of a high sensitivity with a high etching speed.
  • the steps of processing using the first plasma and the processing using the second plasma are performed in an alternate manner according to a periodicity varying between 0.5 second and 120 seconds, and preferably from 2 to 30 seconds, so as to repeat the sequence of the plasma processing steps a plurality of times until the desired removal of material A is obtained.
  • the ratio of the duration of the activation step or the passivation step to the duration of the removal varies between 0.1 and 10 and preferably between 0.5 and 2.
  • the subject matter of the present invention is again an etched composite object likely to be obtained by the process of etching such as defined above. It could be notably an integrated-circuit wafer, or a substrate for a flat screen, or a substrate for solar cells, or a substrate for an electronically printed device.
  • FIG. 1 is a cross-sectional functional view of a processing chamber according to an embodiment corresponding to a plasma processing system of the prior art
  • FIG. 2 is a cross-sectional functional view of a plasma source of the system shown in FIG. 1 ;
  • FIG. 3 is a functional perspective view of a configuration of plasma sources in two independent subassemblies according to an embodiment of the invention
  • FIG. 4 is a perspective functional view of a plasma source of a system of plasma processing according to another embodiment of the invention, comprising two discharge chambers in series;
  • FIG. 5 shows a plasma etching machine of the prior art, that is implemented in the comparative example 2;
  • FIG. 6 shows another plasma etching machine of the prior art, that is implemented in the comparative example 3;
  • FIG. 7 shows the selectivity and etching speed obtained by the process implementing the machine of FIG. 6 (comparative example 3);
  • FIG. 8 shows the evolutions of the etching speed and of the selectivity as a function of the gas mixture measured during the process implemented in the comparative example 3;
  • FIGS. 9 and 10 show the use of two plasma source assemblies of the device according to the invention implemented in the examples according to the invention.
  • FIGS. 11A , 11 B, 11 C shown the timing chart of the operation of the two subassemblies of FIG. 10 ;
  • FIGS. 12 to 14 show the results obtained with the process described in the examples according to the invention and implementing the device shown schematically in FIGS. 9 and 10 ;
  • FIG. 15 shows the result of the etching according to the process described on a silicon oxide layer overlapped with silicon nitride for the fabrication of insulating composite structures.
  • a device for plasma processing consists of different elements: a processing chamber 10 , an assembly 20 of plasma sources 201 , 202 , 203 , a system of gas dispersion gas 30 and/or of isolation of the processing chamber 10 from damaging species generated by each of the plasma sources, a gas confinement system 31 , and a pumping system 40 .
  • the processing chamber 10 is composed of a chamber of specially processed material so as not to interact with the active species created in the plasma and with a shape adapted to the processing of the desired parts, that could be cylindrical, cubic or of another form that will allow the industrial use of the chamber.
  • One of the faces of the processing chamber is intended for loading. It is a “door”. Other faces are intended for the entry of species, it is there that the plasma sources 201 , 202 , 203 are attached and another face most often opposite the sources or at the base of the chamber 10 is intended for pumping the chamber.
  • Each plasma source such as represented in FIG. 2 , is here composed of a gas inlet system 25 , a discharge chamber in the form of a tube 201 , 202 , 203 and a material, inert to the plasma and the diameter of which is adapted to optimize the transfer of radiofrequency power by induction via a coupling device 26 (e.g. an antenna) with several coils connected to a tuner and an RF generator upstream, and an insulating discharge capacitor downstream, not shown.
  • a coupling device 26 e.g. an antenna
  • the vacuum in the processing chamber 10 necessary for the creation of the plasma and for the circulation of the gases, is obtained by pumping using a pump 40 .
  • the pump 40 is e.g. a roughing pump or a turbomolecular pump connected to the base of the chamber 10 , most often facing the sources 201 , 202 , 203 .
  • the gas, enriched with active species, circulates in the chamber 10 before being pumped.
  • FIG. 3 a functional perspective view of a configuration of plasma sources in two independent subassemblies 21 , 22 according to an embodiment of the processing system according to the invention is shown.
  • the subassemblies 21 , 22 are arranged according to concentric rings. Other configurations are, however, possible depending upon the desired final result to be obtained.
  • Each subassembly 21 , 22 comprises at least one plasma source allowing a plasma to be generated.
  • FIG. 3 shows that each subassembly comprises three plasma sources 210 , 211 and 212 for subassembly 21 and 220 , 221 and 222 for the subassembly 22 ).
  • each source comprises a single discharge chamber (here in the form of a tube), while in the subassembly 22 , each source 220 , 221 and 222 comprises two discharge chambers in series (also here in the form of tubes: tubes 2201 and 2202 as illustrated in FIG. 4 ).
  • Each plasma source of a subassembly is supplied independently by radiofrequency power Pi and by a gas i with flow-rate ni.
  • the plasma generated by a subassembly (e.g. the subassembly 21 ) is a partially ionized gas or a gas mixture of different chemical nature from the plasma generated by the other subassembly 22 .
  • a control device controls each of the subassemblies 21 , 22 depending upon a specific configuration by application of radiofrequency power and a gas flow rate specific to each subassembly.
  • the plasma processing system allows the plasma sources to be controlled independently of one another by applying a different radiofrequency power and/or gas flow-rate for each subassembly of sources, in order to be able to control the uniformity of processing, notably between the centre and the edge of a part to process.
  • the different plasma sources 210 , 211 , 212 , 220 , 221 , 222 are advantageously of small size with discharge chambers of small size, here in the form of small-diameter tubes, thus allowing their multiplication in a subassembly (in the case where a source comprises a single discharge chamber, here in the form of a tube) or the multiplication of sources (in the case where a source comprises discharge chambers in series).
  • the multiplication of sources in addition allows the number of active species generated by said subassembly in the processing chamber to be increased. It also allows the processing to be optimized and homogenized even for large-diameter wafers. In fact, by the adequate combination of the diffusion cones of the sources, using their overlap and/or their superposition, and by the management of the circulation of gas via the pumping of the chamber, it is possible to obtain a uniform processing of the surfaces.
  • these plasma sources can be placed in different strategic places so as to correspond to the form to be processed, for the optimization of its processing or the uniformity of its processing.
  • a processing system comprising, for example, two subassemblies arranged in two concentric rings, as illustrated in FIG. 3 .
  • the central ring 21 is here comprised of three discharge chambers (here in the form of tubes 210 , 211 and 212 ) comprising plasma sources (generally between one and six discharge chambers) arranged in the centre of the source and supplied by radiofrequency power PI and by a gas comprised of a mixture of, e.g., O2, Ar, CF4, CHF3, NF3, H2O, H2, Cl2, CF3Br, CxHyFz, etc., mixed in a block F1, where F1 implements a mixing operation with a gas 1 of flow-rate 1.1, a gas 2 of flow-rate 2.1, a gas 3 of flow-rate 3.1, etc. up to a gas n of flow-rate n.1.
  • a second ring 22 surrounds the central ring, that is comprised of, for example, three sources (but preferably between four and eight sources), each comprising two discharge chambers in series, the ring 22 being concentric with the central ring 21 .
  • the different discharge chambers (here in the form of tubes) of the ring 22 are supplied by radiofrequency power P2 and by a gas mixed in a block F2, here a mixture of e.g.
  • one or several concentric rings of plasma sources can advantageously be added (each ring corresponding to a subassembly) to those already existing depending upon the requirements of uniformity, using the same principle.
  • a third ring 23 can be used, surrounding the ring 22 previously described, this ring 23 comprising eight to sixteen discharge chambers (here in the form of tubes), the tubes being supplied by radiofrequency power P3 and by gases mixed in a block F3, said gases being for example O 2 , Ar, CF 4 , CHF 3 , NF 3 , H 2 O, H 2 , Cl 2 , CF 3 Br, C x H y F z , etc., where the block F3 implements a mixing operation with a gas 1 of flow-rate 1.3, a gas 2 of flow-rate 2.3, a gas 3 of flow-rate 3.3, etc. up to a gas n of flow-rate n.3.
  • gases being for example O 2 , Ar, CF 4 , CHF 3 , NF 3 , H 2 O, H 2 , Cl 2 , CF 3 Br, C x H y F z , etc.
  • the block F3 implements a mixing operation with a gas 1 of flow
  • the uniformity of the processes is ensured by the independent control of different zones of the source in terms of gas flow-rate F1, F2, F3 and radiofrequency power P1, P2, P3.
  • each ring corresponds to a subassembly of sources, which subassembly comprises a gas inlet that is specific to said subassembly, connected to the gas inlet of each plasma source of the subassembly considered.
  • a control device controls the flow-rate of gas in the gas inlet of each subassembly.
  • the control device additionally controls the mixture of gas injected in the gas inlet of each subassembly.
  • each subassembly comprises here a conducting element connected to the antenna 26 of each discharge chamber (here in the form of a tube) of the subassembly.
  • the control device controls the radiofrequency power supplied to the conducting element of a subassembly.
  • the substrate is turned to average the speed of processing and thus to improve uniformity.
  • concentric rings in anodized aluminum or quartz are typically added between each source and the substrate to process, typically in the upper part of the processing chamber 10 , these rings being showerheads, such showerheads being used currently in semi-conductor fabrication equipment, to distribute the injection of chemical species over hundreds of injection points.
  • Such rings are formed, with small holes pierced into the lower face thereof, opposite the substrate to process. In the present case, they allow the uniformity of the processing to be improved even more and even reduce the number of discharge chambers necessary to process a substrate of 300 mm and 450 mm.
  • the parameters of the gas flow-rate and radiofrequency power are adjusted from a measurement of the performance in terms of uniformity of the process.
  • a device for measuring the local performances of the process whether for example directly by spectroscopy or indirectly by thickness measurement, it is possible, by multiplexing the sources, to actively correct the process so as to optimize the quality of the processing in terms of speed, of homogeneity and of uniformity while guaranteeing the innocuousness of the processing.
  • Such an adjustment of parameters of gas flow and of radiofrequency power is e.g. performed in the form of a closed cycle or in the form of a feed forward cycle.
  • a feed forward adjustment consists here in measuring the state of the surface of the wafer prior to processing (such as e.g. the thickness of the resin) so as to adjust the processing parameters to compensate for the non-uniformity already present.
  • the closed cycle consists here of measuring the state of the surface of the wafer following processing in order to adjust the process parameters before processing the following wafer.
  • the advantages brought by the plasma processing system described are notably a better uniformity and a better efficiency in terms of processing speed.
  • the multiplexing of sources allows independent control of the flow of active species in terms of quantity, dissociation rate, chemical composition and of energy over certain work zones and thus allows the processing of sensitive components to be actively corrected.
  • the system therefore, allows substrates to be processed without limit of size, which procures a very large potential of applications, beyond the applications of cleaning and stripping.
  • the system also allows a uniform distribution of the gaseous flux of active species to be obtained. It allows the efficiency of residue cleaning and etching speeds to be improved, while increasing considerably the selectivity compared to current performances.
  • the selectivity is the ratio of the etching speed of the target material (e.g. silicon nitride Si3N4) to the etching speed of another exposed material, that ideally must not be etched (e.g. silicon oxide SiO2). Selectivity is critical and must be constantly increased, with the appearance of new generations of technology.
  • the device with the multiple discharge chambers thereof, (here in the form of tubes) allows the selectivity of plasma processes to be increased by independently controlling the etching speed of the target material and that of one or more other exposed materials. The device allows infinite selectivity to be obtained.
  • the alternate use or partial overlap of a stripping plasma generated by a subassembly and of a passivation plasma generated by another subassembly allows this selectivity to be substantially increased.
  • Silicon semiconductor substrates overlapped by a layer of silicon nitride (Si 3 N 4 ) as target material to be etched, and by a layer of silicon oxide SiO 2 as material not to be etched, or by composite zones of the preceding materials;
  • Silicon semiconductor substrates overlapped by a layer of silicon oxide SiO2 (material not to be etched) overlapped by a layer of Si3N4 (target material to be etched);
  • Silicon semiconductor substrates comprising composite zones of the preceding stacks
  • the selectivity is measured by taking the ratio, after processing, of the thickness removed from material A compared to the thickness removed from material B for the same processing time. This can also be expressed in the form of the ratio of the etching or stripping speeds of the two materials.
  • Substrates of silicon overlapped by a layer of silicon nitride (Si 3 N 4 ) and substrates of silicon overlapped by a layer of silicon oxide (SiO 2 ) have been respectively etched by phosphoric acid wet processing.
  • SiO2 In order to determine the etching speed of SiO2, an Si substrate covered only in SiO2 is used, i.e. SiO2/Si, from which SiO2 is partially removed.
  • Si3N4 an Si substrate covered only in Si3N4 is used, i.e. Si3N4/Si or most frequently an Si substrate with Si3N4 on SiO2 i.e. Si3N4/SiO2/Si, from which Si3N4 is partially removed.
  • the process is then applied to the real structure on an Si substrate.
  • the real structure is most often a composite, that is to say made of SiO2 zones and Si3N4/SiO2 zones.
  • the geometry and the topography of the zones depend on the fabrication step ( FIG. 15 is an example thereof).
  • Test wafers such as described above were etched by the plasma process of the prior art presented by the IMEC R&D Centre (Belgium) during the PESM 2012 conference in Grenoble.
  • the plasma etching processing was performed in an etching machine of the company Lam Research such as illustrated in FIG. 5 : it comprises a single discharge chamber and a single chemistry.
  • the applicant has performed selective etching experiments of Si 3 N 4 based on equipment comprising a plasma source comprised of several discharge chambers (here in the form of tubes) such as illustrated in FIG. 6 .
  • the discharge tubes are all connected in parallel and controlled by a single generator. It was not possible to independently control the tubes, that is, to apply a different RF power to the different tubes.
  • the active gases of type O 2 , N 2 , CF 4 , etc. are mixed prior to being injected into the discharge tubes. It was also not possible to inject different gases into different tubes.
  • the plasma source used by the applicant while being composed of a plurality of discharge tubes, generates a single type of plasma in the processing chamber, just like traditional plasma sources (micro-wave or by inductive coupling).
  • FIG. 7 demonstrates the selectivity and the etching speed as a function of different gas mixtures. This figure shows that:
  • FIG. 8 demonstrates the selectivity and the etching speed as a function of the amount of H2 in the gas mixture. It is noted that:
  • the etching speed of Si3N4 and the Si3N4:SiO2 selectivity are closely correlated: the etching speed of Si3N4 decreases when the SiO2 selectivity increases. It is not possible to de-correlate the two in a traditional plasma source configuration (that is, generating a single type of plasma in the processing chamber);
  • the etching speed of Si3N4 is about 80 ⁇ /min for a selectivity Si3N4:SiO2 of 110:1;
  • the etching speed of Si3N4 is about 250 ⁇ /min for a selectivity Si3N4:SiO2 of about 35:1.
  • Comparative examples demonstrate therefore that it is not possible to ally high selectivity with high etching speed (see the results presented in FIG. 8 and comparative example 2).
  • passivation step it serves to protect (or “passivate”) certain surfaces from chemical attack taking place during the etching step.
  • Passivation consists of depositing, onto the substrate, a polymer of type e.g. C x F y H z (e.g. CF 4 , or C 4 F 8 or C 2 F 6 , CHF 3 , CH 3 F, etc.),
  • removal or etching step It serves to remove (“etch”) a material, either partially or entirely.
  • the passivation layer can be partially or entirely removed,
  • each step being of the order of several seconds if not several tens of seconds but also could be extremely short, of the order of 0.1 s.
  • FIG. 11A The time charts of the operation of each source are shown in FIGS. 11A , 11 B and 11 C, respectively for an operation with alternating steps of removal and passivation with no overlap, ( FIG. 11A ), for an operation with steps of removal and passivation with partial overlap ( FIG. 11B ) and steps of removal and passivation with total overlap ( FIG. 11C ).
  • the etching speed of Si3N4 is about 120 ⁇ /min for a selectivity Si3N4:SiO2 of about 700:1 with a CF4/O2/H2 plasma.
  • Temperature of substrate between 135° C. and 150° C.
  • RF power 50 to 1000 W/discharge tube and up to 5000 W for a subassembly composed of a plurality of discharge tubes.
  • etching step CF4, CHF3, CH3F, NF3, C12, HBr, SF6, with or without 02, with or without N2, and their mixtures
  • Additive gases O 2 , N 2 , Ar, H 2 , Xe, He
  • the silicon nitride Si 3 N 4 layer serving as a mask for the fabrication of composite so-called STI (shallow trench isolation) structures, was selectively etched.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Drying Of Semiconductors (AREA)
US14/415,976 2012-07-20 2013-07-22 Device for Treating an Object with Plasma Abandoned US20150243485A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR1257037A FR2993576B1 (fr) 2012-07-20 2012-07-20 Dispositif de traitement d'un objet par plasma
FR1257037 2012-07-20
PCT/FR2013/051768 WO2014013209A1 (fr) 2012-07-20 2013-07-22 Dispositif de traitement d'un objet par plasma

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/FR2013/051768 A-371-Of-International WO2014013209A1 (fr) 2012-07-20 2013-07-22 Dispositif de traitement d'un objet par plasma

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US15/870,890 Division US11075057B2 (en) 2012-07-20 2018-01-13 Device for treating an object with plasma

Publications (1)

Publication Number Publication Date
US20150243485A1 true US20150243485A1 (en) 2015-08-27

Family

ID=47227933

Family Applications (2)

Application Number Title Priority Date Filing Date
US14/415,976 Abandoned US20150243485A1 (en) 2012-07-20 2013-07-22 Device for Treating an Object with Plasma
US15/870,890 Active 2033-12-12 US11075057B2 (en) 2012-07-20 2018-01-13 Device for treating an object with plasma

Family Applications After (1)

Application Number Title Priority Date Filing Date
US15/870,890 Active 2033-12-12 US11075057B2 (en) 2012-07-20 2018-01-13 Device for treating an object with plasma

Country Status (9)

Country Link
US (2) US20150243485A1 (enrdf_load_stackoverflow)
EP (1) EP2875517B1 (enrdf_load_stackoverflow)
JP (1) JP6298814B2 (enrdf_load_stackoverflow)
KR (1) KR102060671B1 (enrdf_load_stackoverflow)
CN (1) CN104685605B (enrdf_load_stackoverflow)
FR (1) FR2993576B1 (enrdf_load_stackoverflow)
SG (1) SG11201500389UA (enrdf_load_stackoverflow)
TW (1) TWI601181B (enrdf_load_stackoverflow)
WO (1) WO2014013209A1 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190080924A1 (en) * 2017-09-13 2019-03-14 Tokyo Electron Limited Selective nitride etching method for self-aligned multiple patterning
US10304688B2 (en) * 2016-08-29 2019-05-28 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10431470B2 (en) 2017-02-23 2019-10-01 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10446405B2 (en) 2017-02-23 2019-10-15 Tokyo Electron Limited Method of anisotropic extraction of silicon nitride mandrel for fabrication of self-aligned block structures
US10658192B2 (en) * 2017-09-13 2020-05-19 Tokyo Electron Limited Selective oxide etching method for self-aligned multiple patterning

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9378975B2 (en) 2014-02-10 2016-06-28 Tokyo Electron Limited Etching method to form spacers having multiple film layers
JP6836953B2 (ja) * 2016-12-13 2021-03-03 東京エレクトロン株式会社 窒化シリコンから形成された第１領域を酸化シリコンから形成された第２領域に対して選択的にエッチングする方法
KR102440367B1 (ko) * 2017-06-22 2022-09-05 삼성전자주식회사 Rps를 이용한 식각 방법 및 그 식각 방법을 포함한 반도체 소자 제조방법

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060276043A1 (en) * 2003-03-21 2006-12-07 Johnson Mark A L Method and systems for single- or multi-period edge definition lithography
US20090191707A1 (en) * 2008-01-25 2009-07-30 Renesas Technology Corp. Method of manufacturing a semiconductor device
US20090286397A1 (en) * 2008-05-15 2009-11-19 Lam Research Corporation Selective inductive double patterning
US20100096367A1 (en) * 2008-10-20 2010-04-22 Industry-University Cooperation Foundation Hanyang University Apparatus for generating remote plasma
US20110244686A1 (en) * 2010-03-31 2011-10-06 Lam Research Corporation Inorganic rapid alternating process for silicon etch
US20110254093A1 (en) * 2009-12-29 2011-10-20 Institute of Microelectronics, Chinese Academy of Sciences Semiconductor device and method of manufacturing the same

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5273609A (en) * 1990-09-12 1993-12-28 Texas Instruments Incorporated Method and apparatus for time-division plasma chopping in a multi-channel plasma processing equipment
US5296272A (en) * 1990-10-10 1994-03-22 Hughes Aircraft Company Method of implanting ions from a plasma into an object
JP3752468B2 (ja) * 1991-04-04 2006-03-08 株式会社日立製作所 半導体装置の製造方法
JP4654176B2 (ja) * 1996-02-22 2011-03-16 住友精密工業株式会社 誘導結合プラズマ・リアクタ
US6267074B1 (en) * 1997-02-24 2001-07-31 Foi Corporation Plasma treatment systems
EP1055249A1 (en) * 1998-02-09 2000-11-29 Applied Materials, Inc. Plasma assisted processing chamber with separate control of species density
US6051073A (en) * 1998-02-11 2000-04-18 Silicon Genesis Corporation Perforated shield for plasma immersion ion implantation
US20010002584A1 (en) * 1998-12-01 2001-06-07 Wei Liu Enhanced plasma mode and system for plasma immersion ion implantation
US20060124588A1 (en) * 1999-01-05 2006-06-15 Berg & Berg Enterprises, Llc System and method for reducing metal oxides with hydrogen radicals
JP2002100623A (ja) * 2000-09-20 2002-04-05 Fuji Daiichi Seisakusho:Kk 薄膜半導体製造装置
JP2004265627A (ja) * 2003-02-14 2004-09-24 Masato Toshima プラズマ発生装置およびプラズマエッチング装置
AT412719B (de) * 2003-06-16 2005-06-27 Eckelt Glas Gmbh Verfahren und vorrichtung zum bereichsweisen entschichten von glasscheiben
US7015415B2 (en) * 2004-02-18 2006-03-21 Dry Plasma Systems, Inc. Higher power density downstream plasma
TWI349042B (en) * 2006-02-09 2011-09-21 Sputtering system providing large area sputtering and plasma-assisted reactive gas dissociation
KR100799175B1 (ko) * 2006-04-21 2008-02-01 주식회사 뉴파워 프라즈마 플라즈마 프로세싱 시스템 및 그 제어 방법
EP1936656A1 (en) * 2006-12-21 2008-06-25 Nederlandse Organisatie voor Toegepast-Natuuurwetenschappelijk Onderzoek TNO Plasma generator and method for cleaning an object
US7976674B2 (en) * 2007-06-13 2011-07-12 Tokyo Electron Limited Embedded multi-inductive large area plasma source
CN201228282Y (zh) * 2007-12-24 2009-04-29 杨思泽 脉冲高能量密度等离子体辅助多源复合材料表面改性装置
JP2010161350A (ja) * 2008-12-09 2010-07-22 Hitachi Kokusai Electric Inc 基板処理方法
US9155181B2 (en) * 2010-08-06 2015-10-06 Lam Research Corporation Distributed multi-zone plasma source systems, methods and apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060276043A1 (en) * 2003-03-21 2006-12-07 Johnson Mark A L Method and systems for single- or multi-period edge definition lithography
US20090191707A1 (en) * 2008-01-25 2009-07-30 Renesas Technology Corp. Method of manufacturing a semiconductor device
US20090286397A1 (en) * 2008-05-15 2009-11-19 Lam Research Corporation Selective inductive double patterning
US20100096367A1 (en) * 2008-10-20 2010-04-22 Industry-University Cooperation Foundation Hanyang University Apparatus for generating remote plasma
US20110254093A1 (en) * 2009-12-29 2011-10-20 Institute of Microelectronics, Chinese Academy of Sciences Semiconductor device and method of manufacturing the same
US20110244686A1 (en) * 2010-03-31 2011-10-06 Lam Research Corporation Inorganic rapid alternating process for silicon etch

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10304688B2 (en) * 2016-08-29 2019-05-28 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10312102B2 (en) * 2016-08-29 2019-06-04 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10515814B2 (en) 2016-08-29 2019-12-24 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10431470B2 (en) 2017-02-23 2019-10-01 Tokyo Electron Limited Method of quasi-atomic layer etching of silicon nitride
US10446405B2 (en) 2017-02-23 2019-10-15 Tokyo Electron Limited Method of anisotropic extraction of silicon nitride mandrel for fabrication of self-aligned block structures
US20190080924A1 (en) * 2017-09-13 2019-03-14 Tokyo Electron Limited Selective nitride etching method for self-aligned multiple patterning
US10607852B2 (en) * 2017-09-13 2020-03-31 Tokyo Electron Limited Selective nitride etching method for self-aligned multiple patterning
US10658192B2 (en) * 2017-09-13 2020-05-19 Tokyo Electron Limited Selective oxide etching method for self-aligned multiple patterning
TWI794289B (zh) * 2017-09-13 2023-03-01 日商東京威力科創股份有限公司 用於自對準多重圖案化之選擇性氮化物蝕刻方法

Also Published As

Publication number Publication date
TWI601181B (zh) 2017-10-01
EP2875517B1 (fr) 2020-05-27
CN104685605A (zh) 2015-06-03
JP2015526897A (ja) 2015-09-10
US11075057B2 (en) 2021-07-27
FR2993576B1 (fr) 2018-05-18
FR2993576A1 (fr) 2014-01-24
EP2875517A1 (fr) 2015-05-27
TW201415520A (zh) 2014-04-16
WO2014013209A1 (fr) 2014-01-23
JP6298814B2 (ja) 2018-03-20
US20180158651A1 (en) 2018-06-07
KR20150038172A (ko) 2015-04-08
SG11201500389UA (en) 2015-03-30
CN104685605B (zh) 2017-05-17
KR102060671B1 (ko) 2019-12-30

Similar Documents

Publication Publication Date Title
US11075057B2 (en) Device for treating an object with plasma
KR102402866B1 (ko) 고 종횡비의 구조체들의 콘택 세정
CN107924838B (zh) 处理衬底的装置与系统及蚀刻衬底的方法
KR102510737B1 (ko) 원자층 에칭 방법
KR101811910B1 (ko) 질화규소막에 피처를 에칭하는 방법
KR101744625B1 (ko) 에칭 방법
KR20210042939A (ko) 전자빔 매개 플라즈마 에칭 및 증착 공정을 위한 장치 및 공정
US8932947B1 (en) Methods for forming a round bottom silicon trench recess for semiconductor applications
US9378969B2 (en) Low temperature gas-phase carbon removal
KR101880831B1 (ko) 가스 펄싱을 사용하는 딥 실리콘 에칭 방법
US20160005833A1 (en) Feol low-k spacers
KR20160084314A (ko) 이방성 텅스텐 에칭을 위한 방법 및 장치
KR20060085281A (ko) 반도체 플라즈마 처리 장치 및 방법
KR102638568B1 (ko) 조정 가능한 원격 해리
KR20200141518A (ko) 낮은 종횡비 적층물의 패터닝을 위한 방법 및 시스템
US20190362983A1 (en) Systems and methods for etching oxide nitride stacks
US20240290623A1 (en) Processing methods to improve etched silicon-and-germanium-containing material surface roughness
Pu Plasma etch equipment
US10418250B2 (en) Etching method using remote plasma source, and method of fabricating semiconductor device including the etching method
KR20210006197A (ko) 기판 처리 장치 및 방법
JP2005259873A (ja) エッチング方法
JP2010267670A (ja) プラズマ処理方法
KR20230008099A (ko) 레지스트 기저층 도포를 위한 탄화규소 필름의 건식 에칭 방법

Legal Events

Date Code Title Description
AS Assignment

Owner name: NANOPLAS, FRANCE

Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE INCORRECT APPLICATION NO. 14/516976 TO READ THE CORRECT APPLICATION NO. 14/415976 PREVIOUSLY RECORDED ON REEL 035314 FRAME 0427. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNORS:BAUJON, GILLES;GUIDOTTI, EMMANUEL;PILLOUX, YANNICK;AND OTHERS;SIGNING DATES FROM 20150209 TO 20150216;REEL/FRAME:038745/0795

AS Assignment

Owner name: PLASMA-THERM, LLC, FLORIDA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NANOPLAS;REEL/FRAME:039176/0887

Effective date: 20160127

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION