CN100413035C - Plasma etching method - Google Patents
Plasma etching method Download PDFInfo
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- CN100413035C CN100413035C CNB2005101310877A CN200510131087A CN100413035C CN 100413035 C CN100413035 C CN 100413035C CN B2005101310877 A CNB2005101310877 A CN B2005101310877A CN 200510131087 A CN200510131087 A CN 200510131087A CN 100413035 C CN100413035 C CN 100413035C
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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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32133—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only
- H01L21/32135—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only
- H01L21/32136—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer by chemical means only by vapour etching only using plasmas
-
- 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
- H01L21/02041—Cleaning
- H01L21/02057—Cleaning during device manufacture
- H01L21/02068—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
- H01L21/02071—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers the processing being a delineation, e.g. RIE, of conductive layers
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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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
- H01L21/321—After treatment
- H01L21/3213—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer
- H01L21/32139—Physical or chemical etching of the layers, e.g. to produce a patterned layer from a pre-deposited extensive layer using masks
Abstract
The present invention provides a plasma etching method avoiding the generation of a fence while being able to etch Ti at a high etching rate, inhibiting the generation of a deposit in a chamber in the process of an etching, and being capable of preventing a particle contamination. The plasma etching method contains a first plasma treatment process in which the plasma of an etching gas comprising a fluorine compound is worked to a body to be treated, to which a mask layer with a formed pattern having at least a specified form and a Ti layer as a layer to be etched formed under the mask layer are formed, at a pressure of 4 Pa or less in a chamber in a treating vessel capable of being held in a vacuum and the Ti layer is etched. The plasma etching method further contains a second plasma treatment process introducing the body to be treated into the treating chamber by the plasma of a cleaning gas and dry-cleaning the body to be treated after the first plasma treatment process. The deposit comprising a Ti compound generated by the first plasma treatment process is removed in the second plasma treatment process.
Description
Technical field
The present invention relates to a kind of plasma-etching method, relate to a kind of plasma of reactant gas that utilizes in detail and on metal films such as Ti, carry out etched plasma-etching method.
Background technology
In semiconductor device, titanium metals such as (Ti) is for example except can be used as wiring material, and the dead resistance that can also be used to form to reduce MOS transistor etc. is the purpose silicide.For example in the manufacture process of MOS transistor, can be embodied in form the Ti film on the surface of gate electrode or diffusion layer after, implement heat treatment and also form silicide, remove the operation of unreacted Ti film.With regard to the technology of removing the Ti film that forms by etching on substrate, motion utilizes CF
4The plasma of the etching gas of class carries out the method (for example patent documentation 1, patent documentation 2) of dry ecthing.
Patent documentation 1: the spy opens clear 53-118372 communique (Fig. 1～Fig. 5 etc.)
Patent documentation 2: the spy opens clear 56-66040 communique (claim etc.)
Summary of the invention
From improving the viewpoint of production capacity, usually preferred high etching speed even when the Ti film carried out etching, also requires to realize handling with high etching speed., for improving etching speed, the method for above-mentioned prior art has all been done any consideration.For example, in the method for patent documentation 2, even in the etching after having carried out pre-etching, also can only obtain the etching speed (same document, with reference to Fig. 1) about 30～40nm/min, and can't satisfy the requirement of present high-rate etching in order to accelerate to begin.
On the other hand, when the plasma of Ti film by the CF class gas of above-mentioned patent documentation 1,2 records carried out high-rate etching, be called as the attachment phenomenon again of the etch residue of fence (Off エ Application ス) sometimes.This phenomenon is that the strong sputter effect of etch residues such as Ti during because of high-rate etching produces and disperse and once more attached to the phenomenon on the side of photic etchant or other metal material.This fence becomes the pollution cause that causes based on Ti, so require to avoid as far as possible producing this fence.
And, when the Ti film is carried out etching with plasma, can form deposit in a large amount of chambers.Because this deposit is that the reason that powder pollutes takes place, so be the obstruction of making high reliability semiconductor device.Therefore, in the plasma etching of Ti film, need take some countermeasures to deposit in the chamber.
Therefore, the purpose of this invention is to provide a kind of generation that at first can avoid fence, simultaneously can carry out etched plasma-etching method with high etching speed to Ti again, and a kind of generation that can suppress deposit in the chamber in etching process is provided, powder is polluted the plasma-etching method of taking precautions against in possible trouble.
In order to solve above-mentioned problem, a first aspect of the present invention provides a kind of plasma-etching method, with the action of plasma of etching gas in the container handling that can keep vacuum, form, and have the mask layer of the pattern that forms the regulation shape at least and as etched layer that below the aforementioned mask layer, forms Ti layer handled object, above-mentioned Ti layer is carried out etching, it is characterized in that, use contains the etching gas of fluorine compounds, carries out etching below cavity indoor pressure 4Pa.
In the plasma-etching method of first aspect, fluorochemical is preferably CF
4And etching speed is preferably 90～140nm/min.
A second aspect of the present invention provides a kind of plasma-etching method, it is characterized in that, comprise: the first plasma treatment operation, below cavity indoor pressure 4Pa, the action of plasma that makes the etching gas that contains fluorine compounds in can keeping the processing room of vacuum, form, and have the mask layer of the pattern that forms the regulation shape at least and, above-mentioned Ti layer carried out etching as the Ti layer of the etched layer that below the aforementioned mask layer, forms; With the second plasma treatment operation, after the first plasma treatment operation finishes, the plasma of cleaning gas imported to carry out dry cleaning in the above-mentioned treatment chamber, in the above-mentioned second plasma treatment operation, remove the deposit that contains the Ti compound that generates by the above-mentioned first plasma treatment operation.
In the plasma-etching method of second aspect, be preferably alternate repetition and implement above-mentioned first plasma treatment operation and the above-mentioned second plasma treatment operation.Moreover employed clean gas is preferably the gas that contains fluorine compounds or oxygen in the above-mentioned second plasma treatment operation.Here, with regard to above-mentioned fluorine compounds, be preferably NF
3Or CF
4
Moreover the cavity indoor pressure in the above-mentioned second plasma treatment operation is preferably below the 6.7Pa.
A third aspect of the present invention provides a kind of control program, it is characterized in that, during operation operation on computers, controls plasma processing apparatus, makes it to carry out the plasma-etching method of above-mentioned first aspect or second aspect.
A fourth aspect of the present invention provides a kind of computer-readable storage medium, store the control program of operation on computers, it is characterized in that above-mentioned control program is in when operation, control employed plasma processing apparatus in the plasma-etching method of above-mentioned first aspect or second aspect.
A fifth aspect of the present invention provides a kind of plasma-etching apparatus, it is characterized in that, comprising: the plasma supply source that produces plasma; Division is used for by above-mentioned plasma handled object being carried out the container handling of the process chamber of etch processes; The supporter of the above-mentioned handled object of mounting in above-mentioned container handling; Be used to make the exhaust unit of step-down in the above-mentioned container handling; Be used to supply gas to the gas feed unit in the above-mentioned container handling; With by control, make the control part that the plasma-etching method of above-mentioned first aspect or second aspect is carried out.
Plasma-etching method of the present invention, the gas that contains fluorine compounds by use carries out plasma etching as etching gas and under the low pressure condition of regulation, when but high etching speed limit etching Ti film is kept on the limit, can prevent the generation of fence effectively.
And, implement plasma etch process and clean to handle by combination based on the plasma of rated condition, can suppress accumulating of deposit in the chamber, so not only can prevent that powder from polluting but also improving the reliability of semiconductor device.
Description of drawings
Fig. 1 is the sectional view that the summary of the expression magnetron RIE plasma-etching apparatus that is used to implement method of the present invention constitutes.
Fig. 2 is the horizontal sectional view of the dipole ring magnet under the state that schematically shows around the chamber of the device that is configured in Fig. 1.
Fig. 3 is used to illustrate the electric field that forms and the schematic diagram in magnetic field in chamber.
Fig. 4 represents the order of the plasma-etching method of first execution mode of the present invention, and the figure of the state when (a) being the expression etching (b) is the figure of the state after the expression etching work procedure finishes.
Fig. 5 is the curve chart of expression based on the waveform separating resulting of the XPS analysis of deposit in the chamber after the plasma etch process.
Fig. 6 is the flow chart of processing sequence of the plasma-etching method of expression second execution mode of the present invention.
Fig. 7 is the Determination of thickness result's of the deposit on the top top board of representing to change after handling gas and cleaning processing a curve chart.
Fig. 8 is the Determination of thickness result's of the deposit on the top top board after expression changes pressure and cleans processing a curve chart.
Fig. 9 is the curve chart of the relation of expression processing of wafers piece number of plasma etching and powder.
Symbol description
1: chamber (container handling), 2: brace table (electrode), 12: gas extraction system, 15: the first high frequency electric sources, 17: adjustment dielectric chamber, 18: gas introducing mechanism, 20: shower nozzle (electrode), 23: treating-gas supply system, 24a, 24b: dipole ring magnet, 100: plasma-etching apparatus, 101:Si substrate, 102:SiO
2Layer, 103:Ti layer, 104: mask layer, W: wafer
Embodiment
Below, with reference to accompanying drawing embodiments of the present invention are described.Fig. 1 is that expression is a purpose to implement the inventive method, the sectional view of the summary of the plasma-etching apparatus 100 of the magnetron RIE mode that can preferably use.This Etaching device 100 is constituted as sealing state, has the subsection cylindrical shape that the bottom 1b by the top 1a of path and big footpath constitutes, and Qi Bibu has for example chamber of aluminum (container handling) 1.
Be provided with the brace table 2 of horizontal support semiconductor wafer (following simply be designated as " wafer ") W in this chamber 1, this semiconductor wafer is the silicon substrate that is formed with the Ti film as handled object.Brace table 2 for example constitutes with aluminium, is supported on across insulation board 3 on the brace table 4 of conductor.In addition, the periphery above the brace table 2 is provided with the focusing ring 5 that for example forms with Si or quartz etc.Above-mentioned brace table 2 and brace table 4 can carry out lifting by the ball screw mechanism with ball screw 7, and the drive part of brace table 4 belows is coated with the bellows 8 with stainless steel (SUS) system.The arranged outside of bellows 8 has ripple pipe box 9.And the arranged outside of above-mentioned focusing ring 5 has baffle plate 10.In addition, chamber 1 ground connection.
Be formed with exhaust passage 11 on the sidewall of the bottom of chamber 1 1b, gas extraction system 12 is connected on this exhaust passage 11.And, by making the vacuum pump work of gas extraction system 12, can make the specified vacuum degree that reduces pressure in the chamber 1.On the other hand, be provided with the gate valve 13 of the input/output port of switch wafer W at the sidewall upside of the bottom of chamber 1 1b.
First high frequency electric source 15 that will be used to form plasma by adaptation 14 is connected on the brace table 2, and the High frequency power of assigned frequency is supplied to brace table 2 from this first high frequency electric source 15.On the other hand, and above it be arranged in parallel back relative with brace table 2 be the shower nozzle 20 that elaborates, these shower nozzle 20 ground connection.Therefore, brace table 2 and shower nozzle 20 are as pair of electrodes performance function.
The surface of brace table 2 is provided with the electrostatic chuck 6 that is used for Electrostatic Absorption and keeps wafer W.This electrostatic chuck 6 is connected DC power supply 16 on the electrode 6a by electrode 6a is constituted between insulator 6b.And, by voltage being applied on the electrode 6a, for example adsorb wafer W in the Coulomb force by electrostatic force by power supply 16.
Be provided with adjustment dielectric chamber 17 in the inside of brace table 2, in this adjustment dielectric chamber 17, the adjustment medium is imported, is discharged and circulated by discharge pipe 17b by ingress pipe 17a, should heat (warm, cold and hot) conduct heat by brace table 2 to wafer W, thus, the treated side of control wafer W is to desired temperatures.
And, even chamber 1 can and keep vacuum by gas extraction system 12 exhausts, can regulate the temperature of wafer W effectively in order to make the adjustment medium that is circulated in the adjustment dielectric chamber 17, gas as heat transfer medium, can utilize gas introducing mechanism 18 and pass through this gas supply pipe road 19, import between electrostatic chuck 6 surfaces and the wafer W back side with authorized pressure (counter-pressure).Like this, by importing the gas as heat transfer medium, the heat of adjustment medium can be communicated on the wafer W effectively, can improve the adjustment efficient of wafer W.
Above-mentioned shower nozzle 20 is arranged on the top section of chamber 1 in the mode relative with brace table 2.Below this shower nozzle 20, be provided with a plurality of gases hole 22 that spues, and have gas introduction part 20a at an upper portion thereof.And portion is formed with space 21 within it.Gas introduction part 20a connects gas supplying tubing 23a, and the other end of this gas supplying tubing 23a is connected with supplies with the treating-gas supply system 23 that etching gas or clean gas etc. are handled gas.
This class is handled gas, by gas supplying tubing 23a, gas introduction part 20a, arrives the space 21 of shower nozzles 20 from treating-gas supply system 23, by gas hole 22 ejections that spue.
On the other hand, around chamber 1 top 1a, dispose concentric shape and a pair of up and down dipole ring magnet 24a, 24b.Shown in the horizontal sectional view of Fig. 2, dipole ring magnet 24a, 24b are made of a plurality of anisotropy fragments (segment) columnar magnet 31 respectively, are installed in the housing 32 of the magnetic of ring-type.In this embodiment, forming columned 16 anisotropy fragment columnar magnets 31 disposes with ring-type.Among Fig. 2, the arrow shown in the fan-shaped columnar magnet 31 of anisotropy is represented magnetized direction, and is as shown in the drawing, and the direction of magnetization of a plurality of anisotropy fragment columnar magnets 31 is little by little departed from, the whole same horizontal magnetic field B that forms in the same direction as.
Therefore, as shown in Figure 3, the space between brace table 2 and shower nozzle 20, form the electric field EL of vertical direction by first high frequency electric source 15, and,, generate magnetron discharge by the vertical electromagnetic field of such formation by dipole ring magnet 24a, 24b formation horizontal magnetic field B.Thus, form the plasma of the etching gas of higher-energy state, wafer W is carried out etching.
Moreover, each component part of plasma-etching apparatus 100 be connected on the process controller 50 with CPU and by the constituting of control.The user interface 51 that is connected with the keyboard of the input operation of instructing for managing plasma Etaching device 100 etc. on the process controller 50 or visual and display unit of showing of the operational situation of plasma-etching apparatus 100 etc. is constituted by engineering management person.
Moreover, be connected with the storage part 52 of the prescription (レ シ ピ) that holds storing control program or treatment conditions data etc. on the process controller 50, this control program is used for being implemented in by the control of this process controller 50 the various processing of operation on the plasma-etching apparatus 100.
And, as required, according to from the indication of user interface 51 etc., access arbitrarily prescription and, under the control of process controller 50, carry out desired processing at plasma-etching apparatus 100 by process controller 50 operations from storage part 52.Moreover above-mentioned prescription also can be used with the state that is stored in the storage medium that for example CD-ROM, hard disk, floppy disk, nonvolatile memory etc. can read, and perhaps for example makes it to transmit at any time and be used by dedicated wires from other device.
Below, with reference to Fig. 4 the plasma-etching method of first execution mode of the inventive method of the plasma-etching apparatus 100 that uses such formation is described.
At first, open the gate valve 13 of Fig. 1, wafer W is input in the chamber 1, mounting makes brace table 2 rise to shown position after on the brace table 2, utilizes the vacuum pump of gas extraction system 12, by exhaust passage 11, is vented in the chamber 1.Shown in Fig. 4 (a), the wafer W of this state has the SiO that on Si substrate 101 lamination has dielectric oxide film
2Layer 102, as the Ti layer 103 of etched layer and the structure of mask layer 104.With regard to mask layer 104, as long as have etching selectivity with Ti layer 103, just limit especially, for example can use photic etchant, based on the firm mask of metal etc. or utilize upper strata that other operation forms etc.And, on mask layer 104, be formed with the pattern of regulation shape.
And, flow with regulation, the processing gas that will contain etching gas and diluent gas imports in the chamber 1 from treating-gas supply system 23, making the pressure in the chamber 1 is below the 4Pa (30mTorr), making the temperature of wafer W (brace table 2) is 50～80 ℃, under this state, the High frequency power of stipulating is supplied on the brace table 2 from first high frequency electric source 15.With regard to the High frequency power that is used to generate plasma,, for example be preferably more than the 2000W, more preferably about 3000～5000W from improving the viewpoint of etching speed.At this moment, be applied on the electrode 6a of electrostatic chuck 6 from DC power supply 16 by voltage with regulation, when for example remaining on wafer W absorption on the electrostatic chuck 6, between as the shower nozzle 20 of upper electrode and brace table 2, form high-frequency electric field as lower electrode by the Coulomb force.Between shower nozzle 20 and brace table 2, form horizontal magnetic field B by dipole ring magnet 24a, 24b,, thus,, produce into magnetron discharge by the Electron drift that generates so form vertical electromagnetic field in the existing interelectrode processing of wafer W space.And the plasma by the etching gas that forms because of magnetron discharge carries out etching to wafer W.At this moment, in common etching, set the gas pressure in the chamber 1 higher, not only can generate the charged particle of ion and electronics, and can generate the free radical of abundant amount,, can improve etching speed by this free radical effective function.Moreover when pressure was low, sputter effect grow was easy to generate fence.Consider this point, in common etching, adopt the condition of the above higher pressure of 6.7Pa (50mTorr).But, in the present embodiment, in the plasma etching of Ti layer 103, as described later, by specially using the low pressure conditions of (i.e. 0～4Pa scope) below the 4Pa, can in the generation that prevents fence, realize for example high-rate etching of 90～140nm/min.
In the present embodiment, use the plasma of RIE type to generate mechanism, High frequency power is applied on the brace table 2 as the lower electrode of mounting wafer W, can directly over handled object, form plasma.Moreover, on one side carry out etching, can make electronics describe the chance that helical orbit and increase and gas molecule collide, so can directly over handled object, realize highdensity plasma by between electrode, forming the magnetic field vertical on one side with electric field.Thus, can carry out etching with more speed.
With regard to regard to employed processing gas in first etching work procedure, from the viewpoint of high-rate etching wafer W, the preferred high gas that contains fluorine compounds of reactivity that uses.Here, with regard to fluorine compounds, for example can enumerate CF
4, C
3F
8, SF
6, S
2F
10, CHF
3, CH
2F
2, C
4F
8Deng.Moreover, when using these fluorine compounds, also can use for example rare gas or N such as Ar, Xe, Kr
2Deng inert gas.
Moreover the gas that is used to utilize gas introducing mechanism 18 heat (warm or cold and hot) to be supplied to effectively the heat transfer medium of wafer W by gas supply pipe road 19 is imported between electrostatic chuck 6 surfaces and wafer W the inside with authorized pressure (counter-pressure).With regard to this gas, for example can use He etc.
In order to form desired plasma, can suitably set the frequency and the output that generate first high frequency electric source 15 that plasma uses.From improving the viewpoint of the plasma density directly over the wafer W, frequency is preferably more than the 10MHz.
In order to improve the plasma density directly over the wafer W, magnetic field is applied to as the brace table 2 of opposite electrode and the processing space between the shower nozzle 20, but in order to bring into play its effect effectively, dipole ring magnet 24a, 24b are preferably and are handling the magnet that the space forms such intensity in the magnetic field more than the 10000 μ T (100G).It has been generally acknowledged that the strong more effect that it improves plasma density in magnetic field increases, but, be preferably below the 100000 μ T (1kG) from the viewpoint of fail safe.
In etching work procedure, shown in Fig. 4 (a), for example utilize CF
4Gaseous plasma etching Ti layer 103.At this moment, in the methods of the invention, can realize for example high-rate etching of the so-called high etching speed of 90～140nm/min.When carrying out plasma etch process under the low pressure below 4Pa, the Ti that constitutes Ti layer 103 becomes TiF
4, will be evaporated because of this low-vapor pressure.By this low pressure etch mechanism, can prevent the generation of fence.And, because of etching forms the Ti of Ti layer 103, except masked layer 104 zone of covering, will be from SiO
2 Layer 102 is removed.Shown in Fig. 4 (b), remaining Ti layer 103 is formed and the same pattern of the pattern of mask layer 104.
Here, the result of the test of effect of the present invention is confirmed in narration.
By with the same plasma-etching apparatus 100 that constitutes of Fig. 1, to having the wafer W with the same Ti layer 103 that constitutes of Fig. 4, use CF
4With Ar as etching gas, under condition shown below, implement the plasma etching of Ti layer 103.
＜condition 1 〉
The intensity in magnetic field=12000 μ T (120G) gradient magnet;
Gradient=the 8.53deg. in magnetic field;
Pressure=4Pa (30mTorr) in the chamber 1;
High frequency power=4000W;
CF
4/ Ar flow=300/600ml/min (sccm);
Top and the bottom interelectrode distance (the following top distance to brace table 2 of shower nozzle 20, below same)=40mm;
He counter-pressure (central part/edge part)=1333/3332.5Pa (10/25Torr)
The temperature of shower nozzle 20=60 ℃;
Temperature=60 of chamber 1 sidewall ℃;
The temperature of brace table 2=50 ℃;
Processing time=53.7 second
＜condition 2 〉
Except that making cavity indoor pressure is 6.7Pa, processing time to be 94.8 seconds, and other is the same with embodiment 1, implements plasma etching.
After the plasma etch process, by scanning electron microscope (SEM) observation condition 1 and condition 2 wafer W separately, the situation of condition 2 is compared with condition 1, though be the weak HIGH PRESSURE TREATMENT of sputter power, observes the fence of vertical bar grain pattern on the sidewall of mask layer 104.With respect to this, the situation of condition 1 is not observe the generation of fence (result all omits diagram).
Moreover after the etching of condition 1, the deposit in the XPS analysis chamber 1 detects the peak value of Ti.The result that waveform separates this Ti peak value as shown in Figure 5.According to this Fig. 5, the Ti that is contained in the provable deposit is mostly with TiF
4Exist.
In the condition 2 of the HIGH PRESSURE TREATMENT of 6.7Pa, although etching speed is up to 140nm/min, but because produced fence as described above, pretend endemism when for the plasma that utilizes fluoro-gas Ti layer 103 being carried out etching, the relation that makes the inhibition of the raising of etching speed and fence have compromise selection (trade off) has obtained affirmation.And in condition 1, when preventing to produce fence, its etching speed is 90nm/min, can realize high-rate etching with practical sufficient etching speed.
According to above situation, contain by utilization fluorine gas plasma and under the low pressure condition below the 4Pa, carry out etch processes, the Ti that constitutes Ti layer 103 can be become TiF
4And make it the evaporation and remove.In etching, can prevent that Ti from having obtained affirmation because of sputter attached to the phenomenon that the fence on photic etchant or other metal film takes place based on this method.
Then, narration makes the plasma-etching method of second execution mode of the present invention of the clean treatment combination of the plasma-etching method of above-mentioned first execution mode and chamber 1.When implementing the plasma etching of first execution mode, in chamber 1, generate a large amount of deposits.Behind this deposit of XPS analysis, distinguish to be mixed with TiF
4With the CF compounds.This deposit is Powdered, so adhere to and be deposited in parts around the wafer W particularly on the top top board (be disposed at the parts of shower nozzle 20 bottoms of Fig. 1, omit diagram), becomes the reason of powder.Therefore, implement plasma etch process and dry cleaning processing, can make stable plasma etch process become possibility by combination.
Fig. 6 is the flow chart of processing sequence of the plasma-etching method of expression second execution mode of the present invention.At first, in operation S101, the Ti cover layer wafer that forms Ti layer 103 is input in the chamber 1, in operation S102, implements plasma etch process.Plasma etch process among this operation S101, the operation S102 is the same with above-mentioned first execution mode, carries out same processing.
After plasma etch process finishes, in operation S103, after carrying out needed processing such as pressure adjustment after the etching, open the gate valve 13 of Fig. 1, from chamber 1, export wafer W.Then, in operation S104, naked Si wafer is input in the chamber 1.Naked Si wafer is the purification wafer that does not have film forming etc.
In operation S105, naked Si wafer is implemented plasma clean processing.With regard to the processing gas during plasma is cleaned, for example suitably use and contain NF
3, CF
4Deng fluorine compounds and O
2Deng gas.Moreover, in handling gas, for example can contain rare gas and N such as Ar, Xe, Kr, He
2Deng inert gas.With regard to the pressure of the clean processing among the operation S105, from improving the viewpoint of cleaning efficient, be preferably 6.7Pa following (i.e. the scope of 0～6.7Pa), more preferably below the 4Pa, most preferably be below the 2Pa.Moreover, with regard to cleaning the temperature of handling, be preferably more than 50 ℃, more preferably more than 80 ℃.
Here, the result who the influence of cleaning effect and causing is studied about the kind of handling gas is described.As handling gas, CF is arranged
4The mist of/Ar, NF
3The mist of/Ar, O
2Three kinds of gases (separately) are implemented to clean under condition shown below, are determined at the thickness of the deposit on the top board of top.
CF
4/ Ar gas:
The intensity in magnetic field=12000 μ T (120G) gradient magnet;
Gradient=the 8.53deg. in magnetic field;
Pressure=4Pa (30mTorr) in the chamber 1;
High frequency power=4000W;
CF
4/ Ar flow=300/600ml/min (sccm);
Top and the bottom interelectrode distance=40mm;
He counter-pressure (central part/edge part)=1333/3332.5Pa (10/25Torr)
The temperature of shower nozzle 20=80 ℃;
Temperature=60 of chamber 1 sidewall ℃;
The temperature of brace table 2=50 ℃;
Processing time=90 second
NF
3/ Ar gas:
Remove and use NF
3Beyond/Ar the gas, with CF
4Implement under the same condition of the situation of/Ar gas.
O
2Gas:
Remove O
2Beyond the gradient=12.88deg. in flow=900ml/min (sccm), magnetic field, with CF
4Implement under the same condition of the situation of/Ar gas.
The measuring point of deposit is the central portion (C) and the edge part (E3) of top top board and is followed successively by pars intermedia (M), first edge part (E1), second edge part (E2) (following identical) from central portion (C) side with about equal intervals between them.Its result as shown in Figure 7.
Distinguish according to Fig. 7: the gas that effect is the highest is NF
3/ Ar, O
2Has the effect of all cleaning the top top board haply, CF
4Two kinds of gas systems of/Ar and other are compared, a little less than the clean effect of first edge part (E1).According to this result, by for example using NF
3/ Ar gas individual processing or at CF
4In/Ar the gas treatment with O
2The gas treatment combination is for example at CF
4Implement O after the/Ar gas treatment
2Gas treatment can obtain desired fully clean effect.
Then, the result who the influence of cleaning effect and causing is studied with regard to processing pressure as shown in Figure 8.Use O
2Gas (separately) under condition shown below, changes pressure (gas flow) and implements to clean, and measures the thickness of the deposit on the top board of top.
The condition of cleaning:
The intensity in magnetic field=12000 μ T (120G) gradient magnet;
Gradient=the 12.88deg. in magnetic field;
Pressure=4Pa (30mTorr) or 2Pa (15mTorr) in the chamber 1;
High frequency power=4000W;
O
2Flow=900ml/min (sccm) or 450ml/min (sccm);
Top and the bottom interelectrode distance=40mm;
He counter-pressure (central part/edge part)=1333/3332.5Pa (10/25Torr)
The temperature of shower nozzle 20=80 ℃;
Temperature=60 of chamber 1 sidewall ℃;
The temperature of brace table 2=50 ℃;
Processing time=90 second
Express according to Fig. 8: be reduced to 2Pa (15mTorr) by making cavity indoor pressure from 4Pa (30mTorr), in about Zone Full of top top board, the thickness attenuation of deposit, clean effect is improved.
In the processing sequence of Fig. 6, after clean finishing, carry out needed processing such as pressure adjustment after, in operation S106, open the gate valve 13 of Fig. 1, wafer W is exported from chamber 1.Then, get back to operation S101 once more, carry out the processing of new Ti cover layer wafer.Clean and also can after the wafer W of the certain piece number of etch processes (for example 1 group), carry out, but as shown in Figure 6, be preferably a Ti cover layer of every plasma etch process wafer, implement the plasma of chamber 1 and clean.Thus, remove the deposit in the chamber 1, also can prevent the powder pollution and realize stable plasma etch process.
Fig. 9 represents to measure flow chart according to Fig. 6 with the powder counter, the result of the powder number more than the 0.5 μ m under following condition during plasma etch process Ti cover layer wafer.In addition, because relatively, the result in the time of will cleaning less than enforcement also together is marked among Fig. 9.
Etching condition:
The intensity in magnetic field=12000 μ T (120G) gradient magnet;
Gradient=the 8.53deg. in magnetic field;
Pressure=4Pa (30mTorr) in the chamber 1;
High frequency power=4000W;
CF
4/ Ar flow=300/600ml/min (sccm);
Top and the bottom interelectrode distance=40mm;
He counter-pressure (central part/edge part)=1333/3332.5Pa (10/25Torr)
The temperature of shower nozzle 20=60 ℃;
Temperature=60 of chamber 1 sidewall ℃;
The temperature of brace table 2=50 ℃;
Processing time=90 second
The condition of cleaning:
The intensity in magnetic field=12000 μ T (120G) gradient magnet;
Gradient=the 8.53deg. in magnetic field;
Pressure=4Pa (30mTorr) in the chamber 1;
High frequency power=4000W;
NF
3/ Ar flow=300/600ml/min (sccm);
Top and the bottom interelectrode distance=40mm;
He counter-pressure (central part/edge part)=1333/3332.5Pa (10/25Torr)
The temperature of shower nozzle 20=80 ℃;
Temperature=60 of chamber 1 sidewall ℃;
The temperature of brace table 2=50 ℃;
Processing time=90 second
Express according to Fig. 9: when not implementing plasma and clean, along with the increase of the processing block number of Ti cover layer wafer, the powder number also increases.With respect to this, clean by implementing plasma every, produce powder hardly, can make the high semiconductor device of reliability.
More than narrated embodiments of the present invention, but the present invention is not limited to above-mentioned execution mode, various distortion can be arranged.
For example, in the above-described embodiment, use the dipole ring magnet to form the unit as the magnetic field of magnetron RIE plasma-etching apparatus 100, but be not limited thereto, if under the pressure of scope of the present invention, can form plasma, can utilize various plasma-etching apparatus 100 such as the capacitive coupling type that do not use magnetic field or inductance coupling high type.
Moreover, in the above-described embodiment, enumerated example, but be not limited thereto based on the pattern etching Ti layer 103 of mask 104, can all be applicable to the etching of Ti layer.
Claims (9)
1. plasma-etching method, the action of plasma that etching gas is stopped in the container handling that can keep vacuum, form, and have the mask layer of the pattern that forms the regulation shape at least and as the handled object of etched layer that below described mask layer, forms Ti layer, described Ti layer is carried out etching, it is characterized in that
Use contains the etching gas of fluorine compounds, at cavity indoor pressure for greater than 2Pa but carry out etching under smaller or equal to the condition of 4Pa.
2. plasma-etching method as claimed in claim 1 is characterized in that,
Fluorochemical is CF
4
3. plasma-etching method as claimed in claim 1 is characterized in that,
Etching speed is 90～140nm/min.
4. a plasma-etching method is characterized in that, comprising:
The first plasma treatment operation, at cavity indoor pressure is greater than 2Pa but under the condition smaller or equal to 4Pa, with the action of plasma of the etching gas of fluorochemical in the container handling that can keep vacuum, form, and have the mask layer of the pattern that forms the regulation shape at least and, described Ti layer carried out etching as etched layer that below described mask layer, forms Ti layer; With
The second plasma treatment operation after the first plasma treatment operation finishes, imports to the plasma of cleaning gas and carries out dry cleaning in the described treatment chamber,
In the described second plasma treatment operation, remove the deposit that contains the Ti compound that generates by the described first plasma treatment operation.
5. plasma-etching method as claimed in claim 4 is characterized in that,
Alternate repetition is implemented described first plasma treatment operation and the described second plasma treatment operation.
6. as claim 4 or 5 described plasma-etching methods, it is characterized in that,
Employed clean gas is the gas that contains fluorine compounds or oxygen in the described second plasma treatment operation.
7. plasma-etching method as claimed in claim 6 is characterized in that,
Described fluorine compounds are NF
3Or CF
4
8. as claim 6 or 7 described plasma-etching methods, it is characterized in that,
Cavity indoor pressure in the described second plasma treatment operation is below the 6.7Pa.
9. a plasma-etching apparatus is characterized in that, comprising:
Produce the plasma supply source of plasma;
Division is used for by described plasma handled object being carried out the container handling of the process chamber of etch processes;
The supporter of the described handled object of mounting in described container handling;
Be used to make the exhaust unit of step-down in the described container handling;
Be used to supply gas to the gas feed unit in the described container handling; With
By control, make the control part that each described plasma-etching method is carried out in the claim 1～8.
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| JP2004353976A JP2006165246A (en) | 2004-12-07 | 2004-12-07 | Plasma etching method |
| JP2004353976 | 2004-12-07 |
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| CN100413035C true CN100413035C (en) | 2008-08-20 |
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| KR (1) | KR100798160B1 (en) |
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| CN101211753B (en) * | 2006-12-29 | 2011-03-16 | 联华电子股份有限公司 | Semiconductor technology |
| KR101139189B1 (en) * | 2007-03-29 | 2012-04-26 | 도쿄엘렉트론가부시키가이샤 | Plasma etching method, plasma processing apparatus, control program and computer redable storage medium |
| KR20120014699A (en) * | 2010-08-10 | 2012-02-20 | 주식회사 하이닉스반도체 | Manufacturing method of semiconductor device |
| CN102820224A (en) * | 2011-06-09 | 2012-12-12 | 上海中科高等研究院 | Interface layer treatment method for TFT (thin film transistor) dry etching process |
| JP5982223B2 (en) * | 2012-08-27 | 2016-08-31 | 東京エレクトロン株式会社 | Plasma processing method and plasma processing apparatus |
| JP6422262B2 (en) | 2013-10-24 | 2018-11-14 | 東京エレクトロン株式会社 | Plasma processing method and plasma processing apparatus |
| JP6504827B2 (en) * | 2015-01-16 | 2019-04-24 | 東京エレクトロン株式会社 | Etching method |
| JP2016157793A (en) * | 2015-02-24 | 2016-09-01 | 東京エレクトロン株式会社 | Etching method |
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| JP3476638B2 (en) * | 1996-12-20 | 2003-12-10 | 東京エレクトロン株式会社 | CVD film forming method |
| JP3626833B2 (en) * | 1997-05-22 | 2005-03-09 | 東京エレクトロン株式会社 | Film forming apparatus and film forming method |
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| KR100281129B1 (en) * | 1998-12-17 | 2001-03-02 | 김영환 | Wiring formation method |
| JP4815724B2 (en) * | 2000-09-08 | 2011-11-16 | 東京エレクトロン株式会社 | Shower head structure and film forming apparatus |
| JP4717295B2 (en) * | 2000-10-04 | 2011-07-06 | 株式会社半導体エネルギー研究所 | Dry etching apparatus and etching method |
| KR100378064B1 (en) * | 2000-12-27 | 2003-03-29 | 동부전자 주식회사 | Method for providing a metal layer in a semiconductor device |
| JP2004200378A (en) * | 2002-12-18 | 2004-07-15 | Semiconductor Energy Lab Co Ltd | Manufacturing method of semiconductor device |
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| US5356478A (en) * | 1992-06-22 | 1994-10-18 | Lam Research Corporation | Plasma cleaning method for removing residues in a plasma treatment chamber |
| CN1147026A (en) * | 1995-05-24 | 1997-04-09 | 日本电气株式会社 | Method of cleaning vacuum processing apparatus |
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| Publication number | Publication date |
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| KR20060063736A (en) | 2006-06-12 |
| TWI420588B (en) | 2013-12-21 |
| JP2006165246A (en) | 2006-06-22 |
| TW200627543A (en) | 2006-08-01 |
| KR100798160B1 (en) | 2008-01-28 |
| CN1787183A (en) | 2006-06-14 |
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