CN104347393A - Method for removing natural oxidation layer at bottom of contact window - Google Patents
Method for removing natural oxidation layer at bottom of contact window Download PDFInfo
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- CN104347393A CN104347393A CN201310323635.0A CN201310323635A CN104347393A CN 104347393 A CN104347393 A CN 104347393A CN 201310323635 A CN201310323635 A CN 201310323635A CN 104347393 A CN104347393 A CN 104347393A
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- 238000000034 method Methods 0.000 title claims abstract description 64
- 230000003647 oxidation Effects 0.000 title abstract 6
- 238000007254 oxidation reaction Methods 0.000 title abstract 6
- 239000010410 layer Substances 0.000 claims abstract description 97
- 229910052751 metal Inorganic materials 0.000 claims abstract description 45
- 239000002184 metal Substances 0.000 claims abstract description 45
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 42
- 229910021332 silicide Inorganic materials 0.000 claims abstract description 33
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000000758 substrate Substances 0.000 claims abstract description 26
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 21
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 16
- 239000011229 interlayer Substances 0.000 claims abstract description 12
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 9
- 230000001590 oxidative effect Effects 0.000 claims description 34
- 230000009471 action Effects 0.000 claims description 10
- 238000002955 isolation Methods 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 5
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 229910052697 platinum Inorganic materials 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 238000012545 processing Methods 0.000 abstract description 6
- 210000002381 plasma Anatomy 0.000 abstract 2
- 229960001866 silicon dioxide Drugs 0.000 abstract 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 18
- 229910052710 silicon Inorganic materials 0.000 description 18
- 239000010703 silicon Substances 0.000 description 17
- 230000008569 process Effects 0.000 description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 239000004065 semiconductor Substances 0.000 description 6
- 238000000137 annealing Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 238000003486 chemical etching Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- QKCGXXHCELUCKW-UHFFFAOYSA-N n-[4-[4-(dinaphthalen-2-ylamino)phenyl]phenyl]-n-naphthalen-2-ylnaphthalen-2-amine Chemical compound C1=CC=CC2=CC(N(C=3C=CC(=CC=3)C=3C=CC(=CC=3)N(C=3C=C4C=CC=CC4=CC=3)C=3C=C4C=CC=CC4=CC=3)C3=CC4=CC=CC=C4C=C3)=CC=C21 QKCGXXHCELUCKW-UHFFFAOYSA-N 0.000 description 4
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- RJCRUVXAWQRZKQ-UHFFFAOYSA-N oxosilicon;silicon Chemical compound [Si].[Si]=O RJCRUVXAWQRZKQ-UHFFFAOYSA-N 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 229920005591 polysilicon Polymers 0.000 description 2
- 238000012797 qualification Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 206010010144 Completed suicide Diseases 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- -1 hexafluoro silicon ammonia Chemical compound 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000004151 rapid thermal annealing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
- H01L21/31116—Etching inorganic layers by chemical means by dry-etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
- H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
- H01L21/285—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation
- H01L21/28506—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers
- H01L21/28512—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic Table
- H01L21/28518—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic Table the conductive layers comprising silicides
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- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Insulated Gate Type Field-Effect Transistor (AREA)
- Electrodes Of Semiconductors (AREA)
Abstract
The invention provides a method for removing a natural oxidation layer at the bottom of a contact window. The method at least comprises the following steps of providing an Si substrate, wherein a grid electrode with lateral wall layers is formed on the Si substrate; then forming a silicon-dioxide interlayer dielectric layer, and forming the contact window in the silicon-dioxide interlayer dielectric layer above a source electrode and a drain electrode at both sides of the grid electrode with the lateral wall layers; removing the partial natural oxidation layer at the bottom of the contact window by adopting Ar plasmas, and then removing the residual natural oxidation layer at the bottom of the contact window by adopting an SiCoNi method. According to the method, the natural oxidation layer at the bottom of the contact window is processed by combining the Ar plasmas with the SiCoNi method, so that the processing time is shorter, the substrate cannot be damaged, and the loss of oxides on the lateral wall of the contact window is reduced; meanwhile, the natural oxidation layer at the bottom of the contact window is effectively removed, a good foreshadowing is provided for the formation of a metal silicide in the next step, the formation of the uniform metal silicide with good contact performance is facilitated, and the qualified rate of products is increased.
Description
Technical field
The invention belongs to field of semiconductor manufacture, relate to a kind of oxide layer minimizing technology, particularly relate to a kind of method removing contact hole bottom natural oxide layer.
Background technology
The development of integrated circuit, just according to Moore's Law, to improve constantly towards integrated level, ultra-large future development that characteristic size constantly reduces, and the vertical and horizontal size of device has entered deep-submicron field all.And for high speed integrated circuit, device operating rate require but more and more higher, simultaneously its power consumption then needs continuous reduction.Meet these requirements, reduce the resistance-type inevitable choice in circuit.Because the longitudinal direction of device size reduces, the Metals-semiconductor contacts hole area constantly reduced makes contact resistance increase to the performance that obviously can affect device, starts to pay attention to for reducing wired in series resistance and the low resistivity material improving contact performance so industrial.As grid and interconnecting metal, metal silicide reduces interconnect delay and is of practical significance.
Film metal silicide is usually used in the transition zone of source electrode, drain and gate and metal interconnected conductive contact in metal-oxide-semiconductor, to reduce the series connection square resistance of device, thus devices switch speed can be improved, this contact layer is formed by the solid phase reaction of metal and silicon substrate, can form ohmic contact between metallic silicide and the silicon of characteristic of semiconductor.In metal suicide growth process, the silicon substrate phase counterdiffusion of metal and doping is also reacted, form metal silicide film layer, but the solubility be generally entrained in metal silicide is very low, so original doping can not enter silicide layer with silicon atom in the silicon layer reacted away, but move to the unreacted silicon substrate of lower floor, define the gathering be entrained in the silicon layer adjacent with metal silicide, improve Effective Doping concentration.In addition, quick thermal annealing process when forming metal silicide film is due to shorter annealing time and very fast temperature rate, usually abnormal high Effective Doping concentration can be obtained, because the solubility of alloy generally increases with the rising of annealing temperature in silicon, doping after cooling down rapidly from high temperature still can be solid-solubilized in the lattice structure of silicon, concentration is often higher than cooled solubility limit, so the contact resistance of silicide and silicon can drop to minimum.Can obtain like this and contact more stable contact performance than metal with the direct of semiconductor.
Due to before the formation process of metal silicide, be usually formed with natural oxidizing layer in atmosphere because expose bottom contact hole, silica has insulation characterisitic, therefore must first remove this natural oxidizing layer before formation metal silicide.SiCoNi prerinse is pre-cleaning processes of new generation, utilizes Nitrogen trifluoride (NF
3) and ammonia (NH
3) chemical etching is carried out to silica, this chemical etching dynamics and intensity all smaller, to silica erosion, there is extraordinary selectivity, reduce the loss of silicon base and the change of profile, the problem of the horizontal undercutting in picture wet etching can not be brought gate shapes.Multiple semiconductor maker is verified, and SiCoNi pre-cleaning processes can obtain lower leakage current and the more concentrated contact resistance of distribution, and this may have benefited from better interface processing, thus obtain evenly metal silicide.The natural oxidizing layer that current SiCoNi prerinse is widely used in before metal silicide is formed is removed in technique.
But SiCoNi prerinse can cause the loss of contact hole sidewall interlayer dielectric layer oxide, makes contact area increase.The reduction SiCoNi prerinse time contributes to solving contact area and becomes large problem, but insufficient surface treatment likely causes metal silicide to form failure.Because metal must could form with silicon face good contact the metal silicide reduced needed for contact resistance, if silicon face process is bad, metal silicide easily forms defect, cannot be formed even completely.IMEC report a kind of metal silicide formed before pre-cleaning processes, adopt HF wet-cleaned to remove the oxide of silicon face in conjunction with a small amount of SiCoNi prerinse, but HF can cause the loss of contact hole side wall oxide equally thus cause contact area to become large.
Therefore, the pre-cleaning method providing a kind of effective removing contact hole bottom natural oxide layer and don't affect contact area is necessary.
Summary of the invention
The shortcoming of prior art in view of the above, the object of the present invention is to provide a kind of method removing contact hole bottom natural oxide layer, easily causing the problem of contact hole sidewall loss for solving method of the prior art.
For achieving the above object and other relevant objects, the invention provides a kind of method removing contact hole bottom natural oxide layer, at least comprise the following steps:
1) a Si substrate is provided, described Si substrate is formed with the grid with side wall layer, described in have in the Si substrate of the grid both sides of side wall layer and be formed with source electrode and drain electrode respectively;
2) in the structure of step 1) acquisition, silicon dioxide interlayer dielectric layer is formed, and described source electrode and drain electrode above silicon dioxide interlayer dielectric layer in form contact hole, described source electrode and drain electrode upper surface is arrived bottom described contact hole, described source electrode and drain electrode upper surface are exposed in air, thus form natural oxidizing layer at described source electrode and drain electrode upper surface;
3) Ar plasma is adopted to remove the source electrode of described contact hole bottom-exposed and the part natural oxidizing layer of drain electrode upper surface;
4) SiCoNi method is adopted to remove source electrode and the remaining natural oxidizing layer of drain electrode upper surface of described contact hole bottom-exposed.
Alternatively, in described step 3), adopt radio-frequency power supply produce and maintain Ar plasma, the power bracket of described radio-frequency power supply is 150 ~ 500 watts, and the action time of described Ar plasma is 3 ~ 10s.
Alternatively, in described step 3), described Ar plasma vertically bombards described natural oxidizing layer.
Alternatively, in described step 4), the action time of described SiCoNi method is 2 ~ 15s.
Alternatively, be formed in described Si substrate shallow trench isolation from, described shallow trench isolation is formed with false grid in the silicon dioxide interlayer dielectric layer of top.
Alternatively, the material of described side wall layer comprises silicon dioxide and/or silicon nitride.
Alternatively, after described step 4), be also included in the source electrode of described contact hole bottom-exposed and the step of drain electrode top formation metal silicide.
Alternatively, the metal in described metal silicide comprise in Ti, Co, W, Ta, Mo, Pt or Ni one or more.
As mentioned above, the method of removal contact hole bottom natural oxide layer of the present invention, there is following beneficial effect: adopt Ar plasma to process with the natural oxidizing layer that SiCoNi method combines bottom to contact hole, the processing time of Ar plasma and SiCoNi method is all shorter, damage can not be formed to substrate, and reduce the oxide loss of contact hole sidewall, effectively eliminate the natural oxidizing layer bottom contact hole simultaneously, formation for next step metal silicide provides good place mat, be conducive to being formed evenly, the metal silicide that contact performance is good, improve the qualification rate of product.
Accompanying drawing explanation
Fig. 1 is shown as the process chart of the method for removal contact hole bottom natural oxide layer of the present invention.
Fig. 2 is shown as the schematic diagram in the method for removal contact hole bottom natural oxide layer of the present invention, Si substrate being formed with grid structure.
Fig. 3 is shown as the schematic diagram forming contact hole in the method for removal contact hole bottom natural oxide layer of the present invention above source electrode and drain electrode.
Fig. 4 is shown as in the method for removal contact hole bottom natural oxide layer of the present invention the schematic diagram adopting Ar plasma to remove the source electrode of contact hole bottom-exposed and the part natural oxidizing layer of drain electrode upper surface.
Fig. 5 is shown as in the method for removal contact hole bottom natural oxide layer of the present invention and adopts SiCoNi method to remove the source electrode of contact hole bottom-exposed and the schematic diagram of the remaining natural oxidizing layer of drain electrode upper surface.
Fig. 6 is shown as the schematic diagram forming metal silicide in the method for removal contact hole bottom natural oxide layer of the present invention above the source electrode of contact hole bottom-exposed and drain electrode.
Element numbers explanation
S1 ~ S4 step
1 Si substrate
2 grids with side wall layer
21 side wall layer
3 source electrodes
4 drain electrodes
5 shallow trench isolations from
6 false grids
7 silicon dioxide interlayer dielectric layers
8 contact holes
9 natural oxidizing layers
10 metal silicides
Embodiment
Below by way of specific instantiation, embodiments of the present invention are described, those skilled in the art the content disclosed by this specification can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by embodiments different in addition, and the every details in this specification also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.
Refer to Fig. 1 to Fig. 6.It should be noted that, the diagram provided in the present embodiment only illustrates basic conception of the present invention in a schematic way, then only the assembly relevant with the present invention is shown in graphic but not component count, shape and size when implementing according to reality is drawn, it is actual when implementing, and the kenel of each assembly, quantity and ratio can be a kind of change arbitrarily, and its assembly layout kenel also may be more complicated.
Refer to Fig. 1, the invention provides a kind of method removing contact hole bottom natural oxide layer, at least comprise the following steps:
Step S1, refers to Fig. 2, provides a Si substrate 1, described Si substrate 1 is formed with the grid 2 with side wall layer, described in have in the Si substrate 1 of grid 2 both sides of side wall layer and be formed with source electrode 3 and drain electrode 4 respectively;
Concrete, shallow trench isolation is formed with from 5 in described Si substrate 1, in the present embodiment, described shallow trench isolation is also formed with false grid 6 above 5, and the object forming false grid (dummy gate) is to maintain gate densities in a certain region to cater to the needs of technique.In another embodiment, described shallow trench isolation can not have false grid above 5 yet.
Concrete, the described grid 2 with side wall layer is the combining structure of polysilicon or polysilicon and metal silicide, grid oxic horizon (not shown) is formed under it, the material of described side wall layer 21 is silicon dioxide, silicon nitride or the combination of the two, and it can be silicon oxide-silicon nitride structure, silicon oxide-silicon nitride-silicon dioxide structure or multi-layer silica dioxide-silicon nitride structure.
Step S2, refer to Fig. 3, the structure that step S1 obtains forms silicon dioxide interlayer dielectric layer 7, and form contact hole 8 in silicon dioxide interlayer dielectric layer 7 above described source electrode 3 and drain electrode 4, described source electrode 3 and drain electrode 4 upper surfaces are arrived bottom described contact hole 8, described source electrode 3 and drain electrode 4 upper surfaces are exposed in air, thus form natural oxidizing layer 9 at described source electrode 3 and drain electrode 4 upper surface;
Concrete, described contact hole 8 connects described source electrode or drain electrode for filling interconnect materials to form metal interconnecting wires.Enter next process after described contact hole 8 need through certain stand-by period owing to being formed, during this period, be positioned at source electrode bottom described contact hole 8 and drain electrode upper surface can form described natural oxidizing layer 9 in atmosphere owing to exposing.
Step S3, refers to Fig. 4, adopts Ar plasma to remove the source electrode 3 of described contact hole 8 bottom-exposed and the part natural oxidizing layer of drain electrode 4 upper surfaces;
Concrete, Ar plasma utilizes radio-frequency power supply to produce and maintains, and radio frequency plasma is the low temperature plasma utilizing high-frequency and high-voltage to make the air ionization of surrounding them and produce.In the present embodiment, have employed two radio-frequency power supplies, one of them radio-frequency power supply is used for producing in reaction cavity and maintains Ar plasma, another radio-frequency power supply is added in described Si substrate 1 back side, effect produces bias voltage, Ar particle in such plasma is subject to the effect of this biasing electric field and vertically bombards described natural oxidizing layer 9, thus removes the described natural oxidizing layer 9 of part, and vertical bombardment can also avoid the oxide layer of described contact hole 8 sidewall to be affected.The situation that described natural oxidizing layer 9 is thinning under Ar action of plasma is shown in Fig. 4.
Concrete, the power bracket of two radio-frequency power supplies is 150 ~ 500 watts, and the action time of described Ar plasma is 3 ~ 10s.In the present embodiment, the power of two radio-frequency power supplies is all preferably 300 watts, and the processing time of Ar plasma is 5s.Under the bombardment effect of Ar plasma, part natural oxidizing layer erupts out from described contact hole 9, thus reaches removal object.Ar plasma bombardment is physical bombardment, and long bombardment can cause damage to substrate, and therefore the present invention only adopts Ar plasma to remove part natural oxidizing layer, because the processing time is shorter, can not cause damage to substrate.
Step S4, refers to Fig. 5, adopts SiCoNi method to remove source electrode 3 and the remaining natural oxidizing layer of drain electrode 4 upper surface of described contact hole 8 bottom-exposed.
SiCoNi method is that one utilizes Nitrogen trifluoride (NF
3) and ammonia (NH
3) chemical etching is carried out to silica, this chemical etching dynamics and intensity all smaller, and very high to the Selection radio of silicon dioxide and silicon, when the silicon dioxide of 100 dusts is etched, there is no the etching to silicon.
Concrete, adopt Nitrogen trifluoride/ammonia remote plasma etching and in-situ annealing, this two step all completes in same cavity.In cavity, Nitrogen trifluoride and ammonia gas react generate ammonium fluoride (NH
4the product such as F), ammonium fluoride reacts as etchant and described natural oxidizing layer 9, thus removes remaining natural oxidizing layer.Ammonium fluoride and natural oxidizing layer react and generate hexafluoro silicon ammonia, hexafluoro silicon ammonia in position in annealing process distillation be decomposed into gaseous products and be drawn out of.Remaining natural oxidizing layer removed situation is in this process shown in Fig. 4.
Concrete, the action time of described SiCoNi method is 2 ~ 15s(second), part natural oxidizing layer is eliminated owing to having adopted Ar plasma above, therefore the action time of SiCoNi method is relative to greatly shortening by SiCoNi method merely, in this example, the action time of described SiCoNi method is preferably 3 ~ 6s.Adopt SiCoNi method effectively to eliminate source electrode and the drain electrode upper surface remaining natural oxidizing layer of described contact hole 8 bottom-exposed in the present invention, and due to the action time of SiCoNi method shorter, the loss of described contact hole 8 side wall oxide can be reduced.
So far, the present invention adopts Ar plasma effectively to eliminate the natural oxidizing layer bottom described contact hole 8 in conjunction with SiCoNi method, and good place mat has been made in the formation for next step metal silicide.Refer to Fig. 6, the method being shown as removal contact hole bottom natural oxide layer of the present invention forms the schematic diagram of metal silicide 10 above the source electrode and drain electrode of contact hole 8 bottom-exposed.
Concrete, first at source electrode and the drain electrode disposed thereon metal of described contact hole 8 bottom-exposed, described metal include but not limited in Ti, Co, W, Ta, Mo, Pt or Ni one or more, can also be other transition metal, not enumerate herein.Rapid thermal annealing is carried out after plated metal, silicon in bottom metal and contact hole 8 is reacted, form described metal silicide 10, and form ohmic contact between silicon substrate, thus constitute a good transition zone, the contact resistance of reduction ohmic contact for follow-up source electrode and drain electrode and metal interconnected wire.
In sum, the method of removal contact hole bottom natural oxide layer of the present invention adopts Ar plasma to combine with SiCoNi method and to process with the natural oxidizing layer on draining the source electrode of contact hole bottom-exposed, the processing time of Ar plasma and SiCoNi method is all shorter, damage can not be formed to substrate, and reduce the oxide loss of contact hole sidewall, effectively eliminate the natural oxidizing layer bottom contact hole simultaneously, formation for next step metal silicide provides good place mat, be conducive to being formed evenly, the metal silicide that contact performance is good, improve the qualification rate of product.So the present invention effectively overcomes various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.
Claims (8)
1. remove a method for contact hole bottom natural oxide layer, it is characterized in that, the method for described removal contact hole bottom natural oxide layer at least comprises the following steps:
1) a Si substrate is provided, described Si substrate is formed with the grid with side wall layer, described in have in the Si substrate of the grid both sides of side wall layer and be formed with source electrode and drain electrode respectively;
2) in the structure of step 1) acquisition, silicon dioxide interlayer dielectric layer is formed, and described source electrode and drain electrode above silicon dioxide interlayer dielectric layer in form contact hole, described source electrode and drain electrode upper surface is arrived bottom described contact hole, described source electrode and drain electrode upper surface are exposed in air, thus form natural oxidizing layer at described source electrode and drain electrode upper surface;
3) Ar plasma is adopted to remove the source electrode of described contact hole bottom-exposed and the part natural oxidizing layer of drain electrode upper surface;
4) SiCoNi method is adopted to remove source electrode and the remaining natural oxidizing layer of drain electrode upper surface of described contact hole bottom-exposed.
2. the method for removal contact hole bottom natural oxide layer according to claim 1, it is characterized in that: in described step 3), radio-frequency power supply is adopted to produce and maintain Ar plasma, the power bracket of described radio-frequency power supply is 150 ~ 500 watts, and the action time of described Ar plasma is 3 ~ 10s.
3. the method for removal contact hole bottom natural oxide layer according to claim 1, it is characterized in that: in described step 3), described Ar plasma vertically bombards described natural oxidizing layer.
4. the method for removal contact hole bottom natural oxide layer according to claim 1, it is characterized in that: in described step 4), the action time of described SiCoNi method is 2 ~ 15s.
5. the method for removal contact hole bottom natural oxide layer according to claim 1, is characterized in that: be formed in described Si substrate shallow trench isolation from, described shallow trench isolation is formed with false grid in the silicon dioxide interlayer dielectric layer of top.
6. the method for removal contact hole bottom natural oxide layer according to claim 1, is characterized in that: the material of described side wall layer comprises silicon dioxide and/or silicon nitride.
7. the method for removal contact hole bottom natural oxide layer according to claim 1, is characterized in that: after described step 4), be also included in the source electrode of described contact hole bottom-exposed and the step of drain electrode top formation metal silicide.
8. the method for removal contact hole bottom natural oxide layer according to claim 8, is characterized in that: the metal in described metal silicide comprise in Ti, Co, W, Ta, Mo, Pt or Ni one or more.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310323635.0A CN104347393A (en) | 2013-07-30 | 2013-07-30 | Method for removing natural oxidation layer at bottom of contact window |
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|---|---|---|---|
| CN201310323635.0A CN104347393A (en) | 2013-07-30 | 2013-07-30 | Method for removing natural oxidation layer at bottom of contact window |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112864085A (en) * | 2019-11-28 | 2021-05-28 | 长鑫存储技术有限公司 | Method for manufacturing semiconductor device |
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