CN1477681A - Plasma etching method and device - Google Patents
Plasma etching method and device Download PDFInfo
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- CN1477681A CN1477681A CNA021298963A CN02129896A CN1477681A CN 1477681 A CN1477681 A CN 1477681A CN A021298963 A CNA021298963 A CN A021298963A CN 02129896 A CN02129896 A CN 02129896A CN 1477681 A CN1477681 A CN 1477681A
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Abstract
The present invention provides a plasma etching method. Between upper electrode and lower electrode the etching gas and plasma for diluting said gas are produced, it utilizes the charge exchange reaction of ions being in said plasma and neutral particles to make the neutral particles be ionized and injected into the semiconductor chip W for etching said chip.
Description
Technical field
The present invention relates to use the plasma of reacting gas, etched bodies such as silicon dioxide film are carried out etched plasma-etching method and device.
Background technology
At semiconductor fabrication, when on semiconductor substrates such as silicon wafer, forming wiring, usually, need on the silicon dioxide film that forms on the substrate, form the routing hole of contact hole or through hole etc.In order to form such routing hole, nearly all use the plasma etching technology that can form high accurate hole effectively recently.This technology is a placement substrate on the inductor of configured electrodes in the double as process chamber, offer in the process chamber as reacting gas with etching gas, simultaneously, by on above-mentioned inductor, adding high frequency voltage, produce the plasma of reacting gas in process chamber, the atomic group by being generated by this plasma, ion etc. are finished etched technology.Reacting gas as at this moment using can have all selections according to etched material.For example when the etch silicon dioxide film, use CHF
3, CF
4Etc. halogen compounds gas.And these gases nearly all do not use separately usually, use with the state that adds reactant gas in as the inert gas such as argon (Ar) gas of diluent gas.In addition, use in the plasma etch techniques of argon gas, carry out this process control by regulating usually as the inductor of lower electrode and the distance between the upper electrode or the high-frequency bias voltage that on lower electrode, adds in this class.
, when using argon gas as diluent gas as everybody knows, the central part of etched film and periphery compare, and rate of etch uprises, i.e. uniformity variation in the face of rate of etch.Like this, at substrate hour, inner evenness is not a problem so, is accompanied by nearest wafer and maximizes and miniaturization, makes qualification rate etc. and becomes major issue.In addition, the relatively more bothersome shortcoming of carrying out process control as mentioned above by interelectrode distance or high-frequency bias voltage is also arranged.
On the other hand, open among the flat 8-64575 the spy and to disclose: during etchings such as through hole,, add the method for helium as diluent gas in order to want to make non-forniciform shape., improve the method for the inner evenness of substrate rate of etch, the still untapped method that goes out easy control about following wafer to maximize.
In view of this present invention be and exploitation, the 1st purpose be to provide a kind of process control easily, the good plasma etching method of rate of etch inner evenness.
On the other hand, the dry corrosion device of parallel plate-type is provided with parallel, mutual opposed pair of plate-shaped electrode basically in vacuum treatment container (vacuum chamber), one side's electrode is connected in earthing potential, to the opposing party's electrode supply high frequency voltage, simultaneously by flowing into given etching gas, produce the plasma of this etching gas between two electrodes, the machined object (etched material) of the processed substrate surface that disposes on a lateral electrode with the atomic group in this plasma, ion or duplet carries out etching.
Usually, the anode coupled configuration type of the processed substrate of configuration on the electrode of ground connection side, mainly the chemical etching that produces by the chemical reaction between atomic group in the plasma and the etched material becomes main body.On the other hand, the negative electrode coupled configuration type of the processed substrate of configuration on the electrode of high frequency input side, ion in the plasma is drawn in by vertical gravitation at processed substrate surface, carries out physics and chemical etching (reactive ion etching) with etched material chemically reactive.
At present, in this device for dry etching, though pass through the plasma density that the variable controls of energy such as etching gas pressure or High frequency power influence the etching and processing characteristic, (especially radially) homogenizing in the space of the plasma density on the processed substrate becomes problem.That is, for the easy step-down of portion of processed substrate center plasma density, on processed substrate, there is the so-called etching and processing characteristic uneven problem (should improve a little) that becomes thus periphery one side.
To a solution of this problem is to increase electrode diameter, make electrode perimeter portion that plasma density reduces than the periphery of processed substrate the radial outside design farther this.Yet, increase processed substrate size recently, further especially increase electrode size, derive from thus to be not suitable for (maximization of cooling body etc., complicated or power consumption increase etc.) excessive, the effective or practical solution of can not saying so.
Summary of the invention
In view of this present invention develops, and its purpose is to provide a kind of plasma etching apparatus that improves the parallel plate-type of plasma density distribution characteristic on the processed substrate.
In addition, the object of the present invention is to provide a kind of plasma-etching apparatus that does not increase electrode size, on processed substrate, realizes the parallel plate-type of plasma density homogenizing.
In order to achieve the above object, the described invention of claim 1, it is characterized in that, produce the plasma of etching gas and diluent gas, make the neutral particle ionization by ion in this plasma and the charge-exchange reaction between the neutral particle, incide etched body, to etched body carry out etched during, as above-mentioned diluent gas, the gas that the charge-exchange collision probability of use argon gas and above-mentioned reaction is high is also selected its mixing ratio, carries out uniform etching by improving plasma uniformity.
The described invention of claim 2 is characterized in that, the high gas of charge-exchange collision probability of described reaction is helium.
The described invention of claim 3 is characterized in that, under the situation of the rate of etch that improves above-mentioned etched body periphery, the ratio by the above-mentioned helium of higher setting uses.
The described invention of claim 4, it is characterized in that, between upper electrode and lower electrode, produce the plasma of etching gas and diluent gas, by making the neutral particle ionization at the ion of this plasma and the charge-exchange reaction of neutral particle, incide etched body, during etched body carried out etching, in order to improve the uniformity of plasma, according to the user mode of the shading ring that on the upper electrode periphery, is provided with, change as the helium of above-mentioned diluent gas use and the mixing of argon gas and recently use.
The inventor etc. have studied in plasma etching the etching mechanism when using argon gas one class diluent gas, found that, in this mechanism, by the ion and the interaction between the neutral particle of plasma generation very big influence are arranged.This phenomenon is as follows.From the etching gas (reacting gas) that relies on plasma generation, generate many ions, neutral particle and electronics.And, so ion that generates and neutral particle fierce collision in plasma, ion is conveyed neutral particle to electric charge, and the ion of forfeiture electric charge becomes the high speed neutral particle, in addition, has the neutral particle ionization of electric charge.Its result, the neutral particle of ionization is quickened by screen layer (sheath) electric field that forms in etched surface, is transported to etched body.By such reaction (charge-exchange reaction), the ion reinforced effects that was communicated with the generation of high speed neutral particle is not lost yet, and makes etchant offer etched body at a high speed, carries out etching.At this moment charge-exchange collision probability is about 50% with argon gas the time, and is about 90% during with helium, and helium holds a safe lead.Its result, by using as carrier gas with helium, it is big that rate of etch becomes, and simultaneously, reduces the rate of etch that is subject to the etched body periphery about external environment condition (for example shielding) and descend.Therefore, can integrally improve rate of etch, can suppress etched body periphery rate of etch simultaneously and descend, improve the inner evenness of rate of etch in the present invention.That is,, can improve the rate of etch of etched body periphery by improving the composite rate of helium to argon.This is that the quality of opposite argon is 40 because the quality of helium is 4, and the quality of helium is 1/10 of an argon, because diffusion coefficient and quality (mass number) are proportional, so the helium of easy diffusion is especially influential to the diffusion of etched body periphery.
In addition, use the mist of helium and argon gas,, can not rely on interelectrode distance or high-frequency bias voltage ground carries out process control, make this control become easy because by selecting the mixing ratio (flow-rate ratio) of these gases as diluent gas.
The described invention of claim 5, the the opposed the 1st and the 2nd electrode is set in the container handling that may obtain vacuum, between the above-mentioned the 1st and the 2nd electrode, add high frequency voltage, simultaneously, by flowing into etching gas, generate the plasma of above-mentioned etching gas, carry out etching at the processed substrate that disposes on to above-mentioned the 2nd electrode with above-mentioned plasma, it is characterized in that, in order to be controlled at above-mentioned processed substrate plasma density distribution characteristic radially, along with above-mentioned the 1st electrode forms towards radial outside, so that near above-mentioned the 2nd electrode.
The described invention of claim 6 is characterized in that, above-mentioned the 1st electrode have along with towards radial outside near the such inclined plane of above-mentioned the 2nd electrode.
In claim 5 and 6 described plasma etching apparatus, along the 1st electrode incline face more near radial outside, then interelectrode gap is narrow more, strengthens by the electric field strength in the ion screen layer of electrode, and plasma density increases near the periphery of treatment substrate.By the contoured profile (position, size, inclination angle etc.) on this inclined plane of suitable selection, can reach on the processed substrate homogenizing of plasma density radially.
The described invention of claim 7, it is characterized in that, the above-mentioned processed substrate that disposes on above-mentioned relatively the 2nd electrode in the above-mentioned inclined plane of above-mentioned the 1st electrode extends, so that opposed near the central part of interior all ends on above-mentioned inclined plane and aforesaid substrate, the peripheral end on above-mentioned inclined plane and the periphery of aforesaid substrate are opposed.
Plasma etching apparatus according to claim 7, the electric field strength humidification of narrow and smallization of the interelectrode gap generation shown in above-mentioned is worked to substrate periphery, simultaneously, because on the protuberance that forms on the peripheral part on inclined plane, obtain to strengthen electric field, so more increased plasma density.Thus, can further improve on the substrate uniformity of plasma density radially.
The described invention of claim 8 is characterized in that, the above-mentioned inclined plane of above-mentioned the 1st electrode forms tabular surface.
The described invention of claim 9 is characterized in that, the above-mentioned inclined plane of above-mentioned the 1st electrode forms flexure plane.
Description of drawings
Fig. 1 is the figure that roughly represents the Etaching device that uses in the plasma etching method of the present invention.
Fig. 2 is the figure of measurement result of the inner evenness of the rate of etch of expression when carrying out each self etching by plasma-etching method of the present invention and existing method.
Fig. 3 measures the inner evenness of rate of etch and the figure of shading ring relation.
Fig. 4 is the cardinal principle sectional arrangement drawing of expression as the parallel plate-type device for dry etching structure of the 1st embodiment of plasma etching apparatus the 1st execution mode of the present invention.
Fig. 5 is the cardinal principle sectional arrangement drawing of expression as the parallel plate-type device for dry etching structure of the 2nd embodiment of plasma etching apparatus the 1st execution mode of the present invention.
Fig. 6 is the figure of expression over against the electric-field intensity distribution characteristic of wafer top.
Fig. 7 is the figure of expression over against the plasma density distribution characteristic of wafer top.
Fig. 8 A, Fig. 8 B, Fig. 8 C are the figure that represents to be used for the value conditions of major part size aspect around the electrode of distribution character of Fig. 6 of being obtained by simulation and Fig. 7 respectively.
Fig. 9 is the figure of the etch profile characteristic of expression device for dry etching shown in Figure 4.
Figure 10 is the figure of the etch profile characteristic of expression device for dry etching shown in Figure 5.
Figure 11 is the cardinal principle sectional arrangement drawing of parallel plate-type device for dry etching structure of the 1st embodiment of expression plasma-etching apparatus the 2nd execution mode of the present invention.
Figure 12 is the figure that is used to illustrate the ring-type protruding member effect of plasma-etching apparatus shown in Figure 11.
Figure 13 is the cardinal principle sectional arrangement drawing of parallel plate-type device for dry etching structure of the 2nd embodiment of expression plasma-etching apparatus the 2nd execution mode of the present invention.
Figure 14 is the cardinal principle sectional arrangement drawing of parallel plate-type device for dry etching structure of the 3rd embodiment of expression plasma-etching apparatus the 2nd execution mode of the present invention.
Embodiment
The following execution mode that plasma-etching method of the present invention and device are described with reference to Fig. 1～Figure 14.
Fig. 1 represents the execution mode of plasma-etching method to Fig. 3, and Fig. 1 is illustrated in the plasma device that uses in this plasma engraving method.On the bottom in the process chamber 2 of this plasma 1 ground connection, lay insulation support plate 3, on this support plate 3, by means of supporting that platform 4 is provided with inductor 5.This inductor 5 constitutes lower electrode, and processed substrate (etched body) is set on it, for example is used to hold the electrostatic chuck 11 that keeps 8 o'clock wafer W.In addition, this inductor 5 is connected on the high pass filter (HPF) 6 of ground connection, connects through adaptation 51 simultaneously and adds the 1st high frequency electric source 50 that high frequency (for example 2MHz) bias voltage is used.Above-mentioned electrostatic chuck 11 has the structure by dielectric film clamping membrane electrode 12, for example, is connected on the DC power supply 13 of 1.5KV.
In the inside of above-mentioned support platform 4 heat-exchanging chamber 7 is set, heat exchange medium may maintain semiconductor wafer W to fixed temperature through ingress pipe 8 and discharge pipe 9 circulations through inductor 5.This temperature control reaches the raising of precision by the gas passage 14 that heat transfer mediums such as He gas are provided is set on the back side of semiconductor wafer W.
The focusing ring 16 of ring-type substantially is set, to surround above-mentioned electrostatic chuck 11 on above-mentioned inductor 5.This focusing ring 16 for example forms by conductivity silicon, has the ion that makes in the plasma function of incident semiconductor wafer effectively.
On above-mentioned electrode support 22, form the gas introduction port 26 that is communicated with the above-mentioned gas chamber, be connected in an end of gas supply pipe 27.Valve 28 and controlling plasma device 29 are set on this gas supply pipe 27, and the other end is connected in to be handled on the gas supply source 30.This processing gas supply source 30 has the fluorohydrocarbon of supply gas (CxFy, for example C
4F
8Gas) or the reacting gas supply source of the etching gas (reacting gas) of hydrogen fluorohydrocarbon gas (CpHqFr) etc. and supply with helium supply source and argon gas feed source and other required gas source of diluent gas, for example source of oxygen can be regulated the gas supply flow rate from these gas sources.
Be connected with the blast pipe 31 that is communicated with exhaust apparatus 35 in the bottom of above-mentioned process chamber 2.This exhaust apparatus 35 comprises turbomolecular pump equal vacuum pump, and the 10mTorr that can reduce pressure in process chamber 2 is to any pressure of 1000mTorr.In addition, gate valve 32 is set on the sidewall of this process chamber 2, makes semiconductor wafer can pass in and out process chamber.
Above-mentioned upper electrode 21 is connected on the 2nd high frequency electric source 40 through feeder rod used therein 33 and adaptation 41, is connected to simultaneously on the low pass filter (LPF) 42.
Below, use the Etaching device of said structure, the plasma-etching method of semiconductor wafer is described, more exactly, the plasma-etching method of the silicon dioxide film that on semiconductor wafer, forms, and uniformity data in the actual film of carrying out the relevant rate of etch that this method obtains.
Under the state of absorption semiconductor wafer, regulating from handling the exhaust velocity of gas supply source 30 gas supplied flows and exhaust apparatus 35 on the electrostatic chuck 11 in process chamber 2, is 20mTorr so that make the pressure in the process chamber 2.On lower electrode 5, add the 1st high frequency power by the 1st high frequency electric source 50 subsequently.At this execution mode, the 1st high frequency power is the frequency of 2MHz, adjusts voltage in the processing, is 1.5kV so that make Vpp voltage, and keeps certain.On upper electrode 21, add the 2nd high frequency power by the 2nd high frequency electric source 40.The 2nd high frequency power is 60MHz, 2500W.Like this, by add high frequency voltage on each electrode, the plasma by the supply gas generation taking place between electrode, carries out the etching of silicon dioxide film based on the neutral particle and the ion that are generated by this plasma.
Fig. 2 represents to make respectively the flow of argon gas and helium different, carries out such etching, measures the result of the inner evenness of rate of etch.The longitudinal axis is represented that the center of semiconductor wafer (silicon dioxide film) is got and is made 1 standardized rate of etch on this figure, transverse axis is represented the position (distance) left from above-mentioned center, in addition, line a (solid line) is illustrated in the situation that process chamber is only supplied with argon gas 300sccm flow, line b (dotted line) expression argon gas is 200sccm, helium is the situation of 100sccm, line c (dotted line) expression argon gas and helium are respectively the situation of 150sccm, line d (chain-dotted line) expression argon gas is 100sccm, helium is the situation of 200sccm, and the situation of helium 300sccm is only used in line e (double dot dash line) expression.
According to Fig. 2 as can be known, with the pairing example of the prior art of only using argon gas (solid line) in, rate of etch is integrally low, central part and periphery relatively will uprise many.Be that inner evenness is not good.On the other hand, in using the example (double dot dash line) of helium, rate of etch height integrally not only, and excellent in uniform in the 50mm scope inner face that begins from the center.In the example that share argon gas and helium, along with helium gas flow increases, the rate of etch of periphery uprises.Therefore, by selecting the flow-rate ratio of helium and argon gas suitably, control electrode spacing or high-frequency bias voltage just can not have desirable inner evenness etching.
Fig. 3 be illustrated in when carrying out etching under other condition, with the same reference result of Fig. 2., this example is that flow-rate ratio at diluent gas does not change, the shading ring 55 of thickness 7mm is new (line f) and the measurement result of (line g) when shading ring becomes 5mm after 100 hours.Here, chamber pressure is 40mmTorr, and adding high frequency power on the lower electrode is 800KHz, 1500W, and adding high-frequency on the upper electrode is 27MHz, 2200W, and electrode spacing is 27mm, C
4F
8Gas is 20sccm, CO
2Gas is 40sccm, and Ar gas is 500sccm, O
2Gas is 10sccm.Judge that from this measurement result when using argon gas as diluent gas, along with the past of time, promptly along with the shading ring attenuation, the rate of etch of wafer perimeter diminishes.Like this, when partly changing rate of etch,, during promptly using,, change both interior uniformities of mixing specific energy chain of command by in argon gas, adding helium according to shading ring thickness by shading ring thickness.
As described above, in plasma-etching method of the present invention, produce the plasma of reacting gas and diluent gas, by using the independent helium or the helium and the argon gas of given mixing ratio as the diluent gas that produces charge-exchange reaction, can make process control easily, rate of etch improves, and inner evenness also improves.In addition, inhomogeneity decline can be compensated by the mixing ratio that changes helium and argon gas according to service time in the etching plane of shading ring between the operating period.
At above-mentioned execution mode, in order to implement plasma-etching method of the present invention, use the plasma-etching apparatus of parallel plate-type as shown in Figure 1, also can be used for the device of this well-known other form in field.That is, the form of article on plasma body Etaching device of the present invention is not stipulated.Illustrated though the silicon wafer that forms silicon dioxide film is carried out etched situation, also go for other and film and the etching of other semiconductor or substrate as etched body.In addition, also can be according to the suitably selected reacting gas of the material of etched body.
Fig. 4～Figure 10 represents the 1st execution mode of plasma etching apparatus of the present invention, and Fig. 4 represents the major part as the device for dry etching 180 of the parallel plate-type of the 1st embodiment in the 1st execution mode.
As shown in Figure 4, this plate device for dry etching 180 is characterised in that, for to the semiconductor wafer W (processed substrate) of carrying out plasma etching on the lower electrode in container handling 110 120 and the distribution character of control plasma density radially, with lower electrode 120 opposed upper electrodes 184 on be provided with more towards radial outside, more near the structure of the such inclined plane 184a of lower electrode 120.This inclined plane 184a sees in the form of a ring from positive (lower electrode 120 sides).
In the present embodiment, with cathode coupler mode supply high frequency voltage between two electrodes 184,120, for example on lower electrode 120, be electrically connected 40MHz high frequency electric source 142A and 3MHz high frequency electric source 142B through capacitor 144A, 144B respectively.In addition, make the diameter of lower electrode 120 also bigger, focusing ring 186 is set on the periphery of electrostatic chuck sheet 128, on the side of lower electrode 120, adhere to simultaneously by for example quartzy interior wall members 188 that forms than electrostatic chuck sheet 128 diameters.
In the device for dry etching 180 of the embodiment 1 of Fig. 4, for the semiconductor wafer W on the lower electrode 120, interior all end 184b of inclined plane 184a should be opposed with the central part annex of semiconductor wafer W, and the peripheral end 184c of inclined plane 184a should be opposed with the periphery of semiconductor wafer W.If watch the interval or the clearance G of 184,120 at two electrodes, interior all end 184b of inclined plane 184a and then in zone than its more close radially inner side, interelectrode gap G maximum, on the zone of the extension of inclined plane 184a, the closer to radial outside, then interelectrode gap G tilts more more lentamente, and stenosis gradually is at the peripheral end 184c of inclined plane 184a and minimum on than the zone of its more close radial outside.At the 1st embodiment, interior all end 184b of inclined plane 184a are extended near the central point on the radially inner side always, it is also passable to make upper electrode make column type.
Like this, for the semiconductor wafer W on the lower electrode 120, by from center wafer portion towards wafer perimeter portion the closer to radial outside, then the narrow more such upper electrode structure of making of interelectrode gap G obtains for example curve A of Fig. 6 and Fig. 7
E, A
NShown electric-field intensity distribution characteristic and plasma density distribution characteristic.
Promptly, in the 1st embodiment, because the ion screen layer along upper electrode 184 is thin more the closer to radial outside to wafer perimeter portion from center wafer portion, so the electric field strength (electric field strength in the ion screen layer) that is close to directly over the wafer is relatively high in wafer perimeter portion side.Moreover form outstanding bend owing to go up with the peripheral end 184c of the opposed inclined plane 184a of wafer perimeter portion, thus in producing near the screen of the ion this layer to the electric field of tilted direction, near the humidification of the electric field strength wafer perimeter portion is had contribution.And with such electric-field intensity distribution characteristic (A of Fig. 6
E) corresponding, the plasma density between wafer perimeter portion top electrode also should strengthen (the A of Fig. 7
N).
Fig. 5 represents the parallel plate-type device for dry etching 190 as the 2nd embodiment in the 1st execution mode of plasma-etching apparatus of the present invention.
In this parallel plate-type device for dry etching 190, as shown in Figure 5, for the semiconductor wafer W on the lower electrode 120, opposed near the interior all end 194b of inclined plane 194a and the periphery of semiconductor wafer W, the peripheral end 194c of inclined plane 194a is positioned at (near the peripheral end of lower electrode 120) outside the semiconductor wafer W.Electrode gap G keeps substantially a certain size from center wafer portion to wafer perimeter portion, in the zone that is close to the wafer perimeter portion outside with stenosis more obliquely.
Like this, for the semiconductor wafer W on the lower electrode 120, near wafer perimeter portion, electrode gap G is the rapid electrode structure of stenosis obliquely in the outside radially, obtains the curve B among for example Fig. 6 and Fig. 7
E, B
NShown electric-field intensity distribution characteristic and plasma density distribution characteristic.
As shown in Figure 6, even in the 2nd embodiment, near wafer perimeter, also can strengthen electric field strength and plasma density.If but compare with the 1st embodiment, then the electric field strength reinforced effects quite a little less than, plasma density reinforced effects lower (Fig. 7).From then on the fact is set out, at the 1st execution mode, as shown in Figure 4, for the semiconductor wafer on the lower electrode 120, interior all end 184b of the inclined plane 184a of upper electrode 184 preferably be positioned at center wafer portion near, in addition, the peripheral end 184c of the inclined plane 184a of upper electrode 184 preferably is positioned near wafer perimeter portion top.
The electric-field intensity distribution characteristic A of Fig. 6
E, B
EAnd the plasma density distribution characteristic A of Fig. 7
N, B
NBe to obtain with analogy method when forming major part around the electrode of apparatus structure of Fig. 4 and Fig. 5 according to the size of the value conditions shown in Fig. 8 A, Fig. 8 B respectively, with the electric field strength E (center) of center wafer position (electrode centers position) and plasma density N (center) as fiducial value, with the electric field strength E of each position radially and plasma density N ratio (relative value) expression to fiducial value.Shown in Fig. 8 C, the electric-field intensity distribution characteristic of apparatus structure and plasma density distribution characteristic are obtained with same analogy method, also respectively as a comparative example with the curve C of Fig. 6, Fig. 7 during with whole of upper electrode (84) tabular surface as level
E, C
NExpression.In Fig. 8 A, Fig. 8 B, Fig. 8 C, vertical line CL is the center line by the center of upper electrode 184,194 and lower electrode 120.
At Fig. 9 and Figure 10, represent rate of etch distribution character one example (determination data) on the wafer of apparatus structure (the 2nd embodiment) of the apparatus structure (the 1st embodiment) of Fig. 4 of designing under the value conditions with Fig. 8 A, Fig. 8 B and Fig. 5 respectively.As main condition determination, processed substrate is made as 8 o'clock semiconductor wafers, the pressure in the container handling 110 is 50mT, the temperature of upper electrode 84 and lower electrode 20 is respectively 60 ℃ and 20 ℃, adopts C in process gas
4H
8/ O
2/ Ar (flow is respectively 20/10/100sccm), the SiO on the etched wafer
2Film.High frequency power is at 40MHz (high frequency electric source 42A) side-draw 1000W, at 3MHz (high frequency electric source 42B) side-draw 2000W.
As shown in Figure 9, at the apparatus structure (the 1st embodiment) of Fig. 4, the mean value that obtains radial etch rate on semiconductor wafer W is 5125 /M (dust/minute), and the wafer inner evenness is ± 5.2% measurement result.
As shown in figure 10, at the apparatus structure (the 2nd embodiment) of Fig. 5, the mean value that obtains radial etch rate on semiconductor wafer W is 4916 /M, and the wafer inner evenness is ± 9.5% measurement result.
Relatively, the apparatus structure of the existing type that under the value conditions of Fig. 8 C, designs (comparative example: omit diagram), under above-mentioned same condition determination, the mean value of radial etch rate is 5033 /M on semiconductor wafer W, the wafer inner evenness is ± 11.0%.
Like this, even at the 1st execution mode,, can make the radially homogenizing of the density of the plasma P R that generates between upper electrode 184 and the lower electrode 120 in semiconductor wafer W especially at as shown in Figure 4 apparatus structure (the 1st embodiment).
At the 1st above-mentioned execution mode, make on the upper electrode 184 the inclined plane 184a that is provided with form tabular surface, and it is also passable to make this inclined plane 184a form the such flexure plane of convex surface or concave surface.The structure that a plurality of inclined plane 184a in concentric shape ground are set on upper electrode 184 is also passable.
Also can make the inclined plane 184a of upper electrode 184,194,194a may be provided with at above-below direction movably towards lower electrode 120, also can radially may be provided with movably.If do like this, by movable inclined, can make etch rate variation radially, can obtain best rate of etch and distribute.
Processed substrate of the present invention is not limited to semiconductor wafer, for example both can be LCD (liquid crystal display) substrate etc. for example, also can be any substrate that possible become the dry ecthing processing object.
As described above, according to parallel flat device for dry etching of the present invention, by with the electrode perimeter portion of processed substrate prepared separation, opposite side on be provided with electric field strength compensation usefulness protuberance structure or be provided with more to the such rake of the approaching more processed substrate-side electrode of this electrode radial outside, can improve plasma density distribution characteristic on the processed substrate.
Figure 11～Figure 14 represents the 2nd execution mode of plasma-etching apparatus of the present invention, and Figure 11 represents the parallel plate-type device for dry etching 200 as the 1st embodiment of the 2nd execution mode.
This parallel plate-type device for dry etching 200 constitutes as the cylindric vacuum chamber of the two ends obturation that is for example formed by aluminium.Be arranged on the sidewall of container handling 210 processed substrate for example semiconductor wafer W in container 210, move into the gate valve of opening during taking out of 212.On container handling 210, be connected with and import the gas supply pipe 214 that etching gas is used, be connected with the blast pipe 216 that vacuum exhaust is used in the bottom surface of container handling 210.Gas supply pipe 214 passes to etching gas supply source (not shown), and blast pipe 216 passes to vacuum pump (not shown).
In container handling 210, reserve certain intervals at central portion, dispose upper electrode 218 and lower electrode 220 in parallel to each other, configuring semiconductor wafer W on lower electrode 220.Two electrodes 218,220 are selected the size (diameter) more bigger than semiconductor wafer W.
On lower electrode 220, be covered with circular electrostatic chuck sheet 228, mounting semiconductor wafer W on this electrostatic chuck sheet 228.This electrostatic chuck sheet 228 is stacked with for example a pair of polyamides resin molding, wherein encloses to be used to rely on electrostatic force absorption thin conductive film 228a semiconductor wafer, that for example formed by Copper Foil to form.This conducting film (Electrostatic Absorption electrode) 228a last through lower electrode 220, support platform 222 and connect the feeder rod used therein 230 of container bottoms, provide the Electrostatic Absorption that produces by DC power supply 232 with given direct voltage.Coil 234 that comprises in this direct voltage supply circuit and capacitor 236 are configured for removing the filter of high-frequency noise.
This device for dry etching is adjacent to or contacts on the circumferential lateral surface of upper electrode 218 and cylindric support sector 240, but, comprise the ring-type protruding member 250 of the pole strength compensation usefulness that vertical dislocation arbitrarily (drop) d may constitute highlightedly in the given range that produces by upper electrode 218 at periphery side towards lower electrode 220.Yes that the conductivity material is good for this ring-type protruding member 250, but also can be the insulating properties material.In the present embodiment, in order to make anode coupled configuration type at upper electrode 218 side supply high frequency voltages, reactive ion in the plasma that produces by automatic biasing or sputter effect is incident upper electrode 218 not only, and with the ring-type of impact strength incident considerably protruding member 250, so preferably can adapt to the material of such sputter effect.
Reserve given interval around peripheral direction on cyclic lug 250, form a plurality of through hole 250a, side direction head and is connected in vertical direction through through hole 250a with bolt 252 below ring-type protruding member 250.And the axial region of spiral 252 can connect the top board face of container 210 up and down, the outside of container 210 (above) screw togather with nut 254.The shim member 256 that is attached on the nut 254 also can have sealing function.By such structure, rotate by nut, make ring-type protruding member 250 in the vertical direction displacement, can regulate overhang (normal throw) to upper electrode 218.
At this device for dry etching, the etched material on semiconductor wafer W surface for example is SiO
2During film, as etching gas CF for example
4And the mist of Ar imports chamber 246 from gas supply pipe 214 through gas and is sent to discharge plasma space between two electrodes 218,220.If do like this, then etching gas (the CF from send into plasma environment atmosphere
4/ generate halogen active particle F in Ar)
*And reactive particles CF
4 +, Ar
+, fall or incide on the semiconductor wafer W on the lower electrode 220, the oxide-film (SiO on wafer W surface by these active particles and reactive ion
2) carry out etching.
In present embodiment, by moving of annular protruding member 250, the electric field that article on plasma body discharge space is corrected or compensation comes from upper electrode 218 sides makes its uniform intensity of radially one-tenth in semiconductor wafer W, thus, owing to can make the concentration homogenizing of the decomposition product in equidirectional plasma density or the plasma, so uniform etching and processing characteristic in can obtaining on semiconductor wafer W.
About Figure 12, the effect of ring-type protruding member 250 is described.Around its that in the plasma P R that the plasma discharge of 218,220 at two electrodes takes place also is diffused into not by the space of 218,220 at two electrodes, stops up (radial outside).Form ion screen layer SH in the boundary of plasma P R and near object.Here, ion screen layer SH is in order to make velocity of electrons and the electric field space that exist more much bigger than cation speed, plasma P R and in abutting connection with voltage between the object or potential change generation in this layer entirely.Along in the ion screen layer SH of upper electrode 218, produce the electric field Ey of vertical direction (Y direction) from plasma P R lateral electrodes 218.
As mentioned above, because in the plasma P R of 218,220 generations of two electrodes (the radial direction outside) diffusion towards periphery, so that one side of electrode perimeter portion becomes easily is also lower than the plasma density of electrode centers portion.Thereby in the ion along upper electrode 218 shielded layer SH, far away more at radial direction ionization electrode central part inevitably, then electric field Ey intensity was low more.; in the device for dry etching of present embodiment; by the effect of ring-type protruding member 250 as follows, strengthened the electric field near the ion screen layer SH upper electrode 218 peripheries, can obtain (radially) uniform plasma density in the face on the semiconductor wafer W.
In more detail, around upper electrode 218, ring-type protruding member 250 is also more side-prominent to lower electrode 220 than upper electrode 218, form normal throw, thus along the electric field E that in the ion screen layer SH of the inboard of this drop or inner peripheral surface 250a, produces the transverse direction (directions X) parallel with electrode 218
xAnd, near the drop edge part 250c of ring-type protruding member 250 ion screen layer SH, the electric field Ey of the transverse electric field Ex of mutually orthogonal drop vertical plane 250a side and the vertical direction of drop horizontal plane 250b side is created in big (enhancing) electric field Es that is combined into interior adipping (direction towards center wafer portion) on the vector.Strengthen electric field Es by this, near the drop edge part (bight) 250 of ring-type protruding member 250, the acceleration or the kinetic energy that give electronics strengthen, and plasma excitation strengthens, and plasma density increases.
Near upper electrode 218 peripheries shown in above-mentioned electric field strength strengthens, and then plasma density strengthens and can realize variable regulation and control by the overhang d of change ring-type protruding member 250.
That is, make overhang d big more, then expand along the transverse electric field Ex generation field of drop vertical plane 250a, strengthening electric field Es also increases, simultaneously, because drop edge part 250c is in the periphery side of lower electrode 220 or semiconductor wafer W, so the degree that plasma density strengthens increases.
Otherwise, make overhang d more little, then the transverse electric field Ex generation field along drop vertical plane 250a dwindles, strengthening electric field Es also reduces, simultaneously, because drop edge part 250c is in the periphery side away from lower electrode 220 or semiconductor wafer W, so the degree that plasma density strengthens reduces.As the condition that is used to obtain the enhancing electric field Es also bigger, need overhang d at least than also big along width (thickness) f of the ion of upper electrode 218 screen layer SH than the vertical direction electric field Ey of upper electrode 218 peripheries under no ring-type protruding member 250 situations.
As mentioned above, in the device for dry etching of present embodiment, being provided with on the periphery of upper electrode 218 can be to the side-prominent ring-type protruding member 250 of lower electrode 220, by the overhang of this ring-type protruding member 250 of variable adjustment or the structure of drop d, moderately strengthen near the electric field strength of upper electrode 218 peripheries, make the radially homogenizing of the density of the plasma P R that generates between two electrodes 218,220 in semiconductor wafer W, and then uniform etching and processing characteristic in can obtaining on semiconductor wafer W.
Figure 13 represents the structure as the parallel plate-type device for dry etching 201 of the 2nd embodiment in the 2nd execution mode.
In this device for dry etching 201, ring-type protruding member 260 is fixedly mounted on the container handling 210, the relative ring-type protruding member 260 of upper electrode 218 1 sides is retreated, make the structure of variable this amount of retreating of adjustment of energy or drop g.
In more detail, vertical lower disposes ring-type protruding member 260 cylindraceous with descending among the circular open 210a that forms on the end face of container handling 210, from the upper end of ring-type protruding member 260 above the container handling 210 of flange 260a that radial outside stretches in the periphery of circular open 210a through O type ring 264 mountings, with bolt 266 fixed installations, and, fixedly mount upper electrode 218 with the cylindric support member 268 of the little circle of ring-type protruding member 260 cardinal principle similar shapes below by (not shown) such as bolts, make the flange portion 268a of cylindric support member 268 stacked on the flange portion 260a of ring-type protruding member 260 through 1 or several pieces ring-type space bars or sheet 270, make with bolt 272 and may load and unload the hard-wired structure in ground.In such structure,, can adjust overhang (drop) g of 260 pairs of upper electrodes 218 of ring-type protruding member arbitrarily by changing stacked number of ring-type space bar 270.
Even in the structure of this variation, moderately strengthen near the electric field strength of upper electrode 218 peripheries, the density of plasma P R that makes 218,220 generations of two electrodes is in the radially homogenizing of semiconductor wafer W, so can be on semiconductor wafer W etching and processing characteristic uniformly in the acquisition face.But, during overhang (drop) g that adjusts ring-type protruding member 260,218,220 at two electrodes apart from interval variation, thus the etching and processing characteristic for example etching speed also change.Since this variation be on semiconductor die W in uniformly, so the interior vacuum degree of pressure that can be by adjusting etching gas, container handling 210 can compensate easily from the supply capability of high frequency electric source 242 etc.
Figure 14 represents the structure as parallel plate-type device for dry etching 202 major parts of the 3rd embodiment of the 2nd execution mode.In this variation, on the periphery of upper electrode 218, be provided with to the outstanding ring-type protruding member 274 of lower electrode 220 side multistages, and make on ring-type protruding member 274 variable adjustment or select the structure of multistage drop structure.
In more detail, ring-type protruding member 274, different annular slab 274A, 274B, the 274C of the stacked a plurality of internal diameters in multistage ground ...In this multistage structure, the annular slab 274A of internal diameter minimum is pasting that the superiors are upper electrode 218 among Figure 14, (274B, 274C that internal diameter is big more ...) be configured in lower layer side among Figure 14, i.e. the 2nd electrode 220 sides.At each annular slab 274A, 274B, 274C ... go up and reserve given interval at circumferencial direction, on same place or position, form hole 275, connect the hole 210b of each hole 275 and container 210 downwards with bolt 276 from container handling 210 medial heads, the outside of container 210 (above) screw togather with nut 278 in the screw portion at bolt 276.Can select annular plate 274A, 274B, 274C arbitrarily ... each thickness of slab, internal diameter separately also can be in guaranteeing the multistage relation extents of epimere be selected arbitrarily.The head of bolt 276 and the shim member that is installed with on nut 280,282 also can have sealing function.
According to the ring-type protruding member 274 of such multistage drop structure, owing on the edge part of each section, can strengthen electric field, so these strengthen electric fields by combination, density distribution characteristic radially that can meticulous more variable adjustment semiconductor wafer W.
In this variation, also can one or more pieces be stacked by making same diameter annular plate, constitute ring-type protruding member 274.At this moment, by changing the kind or the internal diameter (for example changing into 274B) of annular plate, also can make the structure of the internal diameter of variable adjustment ring-type protruding member 274 from 274A.
As the path that between two electrodes, flows into etching gas, the air vent hole that provides etching gas to supply with usefulness is provided on upper electrode 218 in replacement, etching gas tube connector (not shown) is connected the side of container handling 210, the structure of etching gas being sent between two electrodes 218,220 from the side also is fine.
In the above-described embodiment, upper electrode 218,218 ' on make the anode coupled configuration type (anode coupling) of input high frequency voltage, and the negative electrode coupled configuration type (negative electrode coupling) of making supply high frequency voltage on lower electrode 20 sides of mounting semiconductor wafer W also is fine.In addition, the outer structure of upper electrode 18,18 ' be arranged on container handling also is fine.
The ring-type protruding member the 250,260, the 274th of above-mentioned execution mode has drop edge, right angle, cross section, yet also can be as acute angle or drop edge, obtuse angle, can also have curved surface structure at fall-part.
Claims (9)
1. plasma-etching method, it is characterized in that: the plasma that produces etching gas and diluent gas, charge-exchange reaction by ion in this plasma and neutral particle makes the neutral particle ionization, incide etched body, etched body is carried out etched during, as described diluent gas, selected and use the high gas and the mixing ratio thereof of charge-exchange collision probability of argon gas and described reaction, by improving the uniformity of plasma, carry out uniform etching.
2. plasma-etching method as claimed in claim 1 is characterized in that: the high gas of charge-exchange collision probability of described reaction is helium.
3. plasma-etching method as claimed in claim 2 is characterized in that: when improving the rate of etch of described etched body periphery, the ratio of setting described helium by highland more uses.
4. plasma-etching method is characterized in that:
Between upper electrode and lower electrode, produce the plasma of etching gas and diluent gas, make the neutral particle ionization, incide etched body by the ion of this plasma and the charge-exchange reaction of neutral particle, to etched body carry out etched during,
In order to improve plasma uniformity,, change and recently use as the mixing of employed helium of described diluent gas and argon gas according to the user mode of the shading ring that around upper electrode, is provided with.
5. plasma-etching apparatus, the the opposed the 1st and the 2nd electrode is set in the container handling that can obtain vacuum mutually, by when between the described the 1st and the 2nd electrode, applying high frequency voltage, flow into etching gas, generate the plasma of described etching gas, with described plasma the processed substrate that disposes is being carried out etching on described the 2nd electrode, it is characterized in that:
In order to control the plasma density distribution characteristic radially of described processed substrate,, form described the 1st electrode with along with towards the mode of radial outside near described the 2nd electrode.
6. plasma-etching apparatus as claimed in claim 5 is characterized in that: described the 1st electrode have along with towards radial outside near the such inclined plane of described the 2nd electrode.
7. plasma-etching apparatus as claimed in claim 6, it is characterized in that: the described inclined plane of described the 1st electrode, with respect to the described processed substrate that on described the 2nd electrode, disposes, opposed near interior all ends on described inclined plane and the portion of described substrate center, the peripheral end on described inclined plane is extended, so that opposed with the periphery of described substrate.
8. as claim 6 or 7 described plasma-etching apparatus, it is characterized in that: the described inclined plane of described the 1st electrode forms tabular surface.
9. as claim 6 or 7 described plasma-etching apparatus, it is characterized in that: the described inclined plane of described the 1st electrode forms flexure plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02129896 CN1240113C (en) | 2002-08-20 | 2002-08-20 | Plasma etching method and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02129896 CN1240113C (en) | 2002-08-20 | 2002-08-20 | Plasma etching method and device |
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| CN1477681A true CN1477681A (en) | 2004-02-25 |
| CN1240113C CN1240113C (en) | 2006-02-01 |
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| CN 02129896 Expired - Fee Related CN1240113C (en) | 2002-08-20 | 2002-08-20 | Plasma etching method and device |
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100369214C (en) * | 2005-12-02 | 2008-02-13 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Grate etching method |
| CN100390933C (en) * | 2004-12-09 | 2008-05-28 | 东京毅力科创株式会社 | Gas supply unit, substrate processing apparatus, and supply gas setting method |
| US7655572B2 (en) | 2005-10-24 | 2010-02-02 | Tokyo Electron Limited | Semiconductor device manufacturing method, semiconductor device manufacturing apparatus, control program and computer storage medium |
| CN101800160A (en) * | 2008-12-26 | 2010-08-11 | 东京毅力科创株式会社 | Substrate processing method |
| US8138444B2 (en) | 2008-04-03 | 2012-03-20 | Tes Co., Ltd. | Plasma processing apparatus |
| CN102522330A (en) * | 2008-12-26 | 2012-06-27 | 东京毅力科创株式会社 | Substrate processing method |
| CN104350585A (en) * | 2012-06-20 | 2015-02-11 | 东京毅力科创株式会社 | Plasma processing apparatus and plasma processing method |
| CN108878328A (en) * | 2014-07-24 | 2018-11-23 | 东京毅力科创株式会社 | Substrate board treatment and substrate processing method using same |
| CN110544645A (en) * | 2018-05-28 | 2019-12-06 | 北京北方华创微电子装备有限公司 | Uniform flow member for process chamber, process chamber and semiconductor processing equipment |
| CN111954360A (en) * | 2020-09-18 | 2020-11-17 | 云南电网有限责任公司电力科学研究院 | Large-area cold plasma generating device and method based on mixed gas |
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| CN100390933C (en) * | 2004-12-09 | 2008-05-28 | 东京毅力科创株式会社 | Gas supply unit, substrate processing apparatus, and supply gas setting method |
| US7655572B2 (en) | 2005-10-24 | 2010-02-02 | Tokyo Electron Limited | Semiconductor device manufacturing method, semiconductor device manufacturing apparatus, control program and computer storage medium |
| CN100369214C (en) * | 2005-12-02 | 2008-02-13 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Grate etching method |
| US8138444B2 (en) | 2008-04-03 | 2012-03-20 | Tes Co., Ltd. | Plasma processing apparatus |
| CN102522330B (en) * | 2008-12-26 | 2015-05-13 | 东京毅力科创株式会社 | Substrate processing method |
| CN101800160A (en) * | 2008-12-26 | 2010-08-11 | 东京毅力科创株式会社 | Substrate processing method |
| CN102522330A (en) * | 2008-12-26 | 2012-06-27 | 东京毅力科创株式会社 | Substrate processing method |
| CN101800160B (en) * | 2008-12-26 | 2015-05-13 | 东京毅力科创株式会社 | Substrate processing method |
| CN104350585A (en) * | 2012-06-20 | 2015-02-11 | 东京毅力科创株式会社 | Plasma processing apparatus and plasma processing method |
| CN108878328A (en) * | 2014-07-24 | 2018-11-23 | 东京毅力科创株式会社 | Substrate board treatment and substrate processing method using same |
| CN108878328B (en) * | 2014-07-24 | 2022-08-23 | 东京毅力科创株式会社 | Substrate processing apparatus and substrate processing method |
| CN110544645A (en) * | 2018-05-28 | 2019-12-06 | 北京北方华创微电子装备有限公司 | Uniform flow member for process chamber, process chamber and semiconductor processing equipment |
| CN113179676A (en) * | 2019-11-27 | 2021-07-27 | 东芝三菱电机产业系统株式会社 | Active gas generating device |
| CN113179676B (en) * | 2019-11-27 | 2024-04-09 | 东芝三菱电机产业系统株式会社 | Active gas generating device |
| CN111954360A (en) * | 2020-09-18 | 2020-11-17 | 云南电网有限责任公司电力科学研究院 | Large-area cold plasma generating device and method based on mixed gas |
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