The application is that the application number that proposed on July 29th, 2005 is dividing an application of 200510088802.3 application of the same name.
Summary of the invention
The present invention proposes in view of the above problems, and its purpose is to provide a kind of plasma processing apparatus and method of plasma processing, can reduce the inequality of the etch processes speed in the real estate, improves the uniformity of the processing substrate in the real estate.
To achieve these goals, the present invention is a kind of plasma processing apparatus that uses plasma to come treatment substrate, it is characterized in that, comprising: accommodate the container handling that substrate is handled; Contain the lower electrode of putting substrate at said container handling; In said container handling, said relatively lower electrode and the upper electrode that disposes; First high frequency electric source is supplied with first RF power to said lower electrode, between said lower electrode and said upper electrode, produces plasma; Second high frequency electric source is supplied with the second low RF power of frequency than first RF power to said lower electrode, is used for the ion of said plasma is introduced to said substrate; With the electrical characteristic adjustment part, it is connected with said upper electrode, and adjustment is with respect to the impedance of the circuit of the electrode one side frequency that is present at least one high frequency in the said container handling, that see from said plasma, so that circuit does not resonate.
The circuit of electrode one side of seeing from plasma in the present invention, comprises: sheath zone, said electrode, said lead and electrical characteristic adjustment part.
According to the present invention, can adjust impedance, so that the circuit of electrode one side does not resonate.According to inventor's checking, through reducing the inequality of the etch processes speed in the real estate in the container handling like this.Therefore, can in real estate, the speed with equalization carry out Cement Composite Treated by Plasma, thereby can improve the uniformity of the processing substrate in the real estate.
The impedance in the circuit of relative counter electrode one side of the supply electrode of said RF power also can adjusted and supply with in said electrical characteristic adjustment part.Wherein, among the present invention, when under the situation of lower electrode and upper electrode both sides supply high frequency electric power, if with lower electrode as supplying with electrode, then upper electrode becomes counter electrode, if with upper electrode as current electrode, then lower electrode becomes counter electrode.
Said electrical characteristic adjustment part also can have the variable element that is used to change said impedance.Said electrical characteristic adjustment part can also have the control part of the said variable element control group of adjustment.
Said electrical characteristic adjustment part can also have the impedance detection portion of detecting said impedance.At this moment, said control part also can be according to adjusting said variable element from the testing result of said impedance detection portion, thereby can control group.
Said electrical characteristic adjustment part can also have the electrical characteristic adjusting mechanism of electrode one side that is connected the said impedance of adjustment, from the electrode surface in the face of said plasma the reactance the circuit of electrical characteristic adjusting mechanism is adjusted into negative value.
Said electrical characteristic adjustment part can also be to adjust said impedance at ± 10 Ω from resonance point with the interior mode that staggers.
In addition, the negative value below-50 Ω also can be adjusted to said reactance in said electrical characteristic adjustment part.At this moment, because the said impedance in the circuit on the electrode is staggered from resonance point significantly, therefore, the electrical properties on the electrode is stable, and the aberrations in property of the electrical properties that between the device of Cement Composite Treated by Plasma, produces of resulting from has obtained reduction.
In addition, said upper electrode can be divided into a plurality of electrode part, and said electrical characteristic adjustment part is provided with respect at least one electrode part.
In addition, in above-mentioned plasma processing apparatus, can have the DC power supply that applies direct voltage at least one side of said upper electrode or said lower electrode.In addition, said upper electrode is applied in above-mentioned direct voltage.
According to the present invention on the other hand, be to use plasma to come the plasma processing apparatus of treatment substrate, it is characterized in that, comprising: accommodate the container handling that substrate is handled; Contain the lower electrode of putting substrate at said container handling; In said container handling, said relatively lower electrode and the upper electrode that disposes; Supply with first RF power to said lower electrode, between said lower electrode and said upper electrode, produce first high frequency electric source of plasma; Second high frequency electric source is supplied with the second low RF power of frequency than first RF power to said lower electrode, is used for the ion of said plasma is introduced to said substrate; With the electrical characteristic adjustment part, be connected with said upper electrode, and the electrical characteristic of the circuit of said electrode one side that adjustment is seen from said plasma does not reach maximum so that flow into the current value of the electric current of electrode from said processing space.
According to the present invention, can adjust the electrical characteristic in the circuit of this electrode one side, do not reach maximum so that flow into the current value of electrode one side.According to inventor's checking, through reducing the inequality of the Cement Composite Treated by Plasma speed in the real estate in the container handling like this.Therefore, can in real estate, the speed with equalization carry out Cement Composite Treated by Plasma, thereby can improve the uniformity of the processing substrate in the real estate.
The electrical characteristic in the circuit of the relative counter electrode of said RF power one side also can adjusted and supply with in said electrical characteristic adjustment part.
Said electrical characteristic adjustment part also can have the variable element that is used to change said current value.In addition, said electrical characteristic adjustment part can also have the said variable element of adjustment and comes the control part of Control current value.
Said electrical characteristic adjustment part also can have the current value test section that detects said current value.At this moment, said control part also can be according to adjusting said variable element from the testing result of said current value test section, thereby can the Control current value.
Said electrical characteristic also can be adjusted in said electrical characteristic adjustment part, makes said current value reach more than 1/2 of lowest high-current value.
Said upper electrode also can be divided into a plurality of electrode part, has said electrical characteristic adjustment part with respect to an electrode part at least.
In addition, in above-mentioned plasma processing apparatus, can have the DC power supply that applies direct voltage at least one side of said upper electrode or said lower electrode.In addition, said upper electrode is applied in above-mentioned direct voltage.
According to the present invention on the other hand; Be a kind of method of plasma processing, it is characterized in that: in container handling, on the lower electrode that substrate-placing is disposed in relative upper electrode; To said lower electrode supply high frequency electric power; Between said lower electrode and said upper electrode, produce plasma, supply with the second low RF power of frequency, be used for the ion of said plasma is introduced to said substrate than first RF power to said lower electrode; Come treatment substrate through this plasma; Wherein, adjustment is with respect to the impedance the circuit of the electrode one side frequency that is present at least one high frequency in the said container handling, that see from said plasma, so that said circuit does not resonate.
As the present invention, through the impedance in the circuit of adjusting electrode one side circuit is not resonated, and can reduce the inequality of the Cement Composite Treated by Plasma speed in the real estate in the container handling.Therefore, can in real estate, the speed with equalization carry out Cement Composite Treated by Plasma, can improve the uniformity of the processing substrate in the real estate.
In said method of plasma processing, also can adjust, make said impedance from resonance point stagger ± 10 Ω in.
According to the present invention on the other hand; Be a kind of method of plasma processing, it is characterized in that: in container handling, on the lower electrode that substrate-placing is disposed in relative upper electrode; Supply with first RF power to said lower electrode; Between said lower electrode and said upper electrode, produce plasma, supply with the second low RF power of frequency, be used for the ion of said plasma is introduced to said substrate than first RF power to said lower electrode; Come treatment substrate through this plasma; Wherein, the electrical characteristic of the circuit of said electrode one side that adjustment is seen from said plasma makes the current value that flows into the electric current of electrode from said processing space not reach maximum.
As the present invention,, make the current value of the electric current that flows into electrode one side not reach maximum, and can reduce the inequality of the Cement Composite Treated by Plasma speed in the real estate in the container handling through adjusting the electrical characteristic on the said electrode.Therefore, can in real estate, the speed with equalization carry out Cement Composite Treated by Plasma, can improve the uniformity of the processing substrate in the real estate.
In said method of plasma processing, also can adjust the electrical characteristic in the circuit of said counter electrode one side, make the current value of the electric current that flows into counter electrode one side relative not reach maximum with the supply electrode of supplying with said RF power.
In said method of plasma processing, also can adjust said electrical characteristic, make said current value reach more than 1/2 of lowest high-current value.
In addition, in above-mentioned method of plasma processing, can apply direct voltage at least one side of said upper electrode or said lower electrode.In addition, said upper electrode imposes direct voltage.
According to the present invention, the speed that can reduce the Cement Composite Treated by Plasma in the real estate is uneven, therefore, can improve the uniformity of the processing substrate in the real estate.
Embodiment
Below, the preferred embodiment for the present invention is described.Fig. 1 is the longitudinal section key diagram of expression as the brief configuration of the plasma-etching apparatus 1 of plasma processing apparatus of the present invention.Wherein, in this specification and accompanying drawing, the structural element that has the identical function structure is in fact marked prosign and omits repeat specification.
As shown in Figure 1, plasma-etching apparatus 1 for example has the container handling that the round-ended cylinder shape is arranged 2 of top opening.Container handling 2 ground connection.Central part in container handling 2 is provided with double as and carries the lower electrode 3 of putting platform that carries of putting wafer W.This lower electrode 3 can move up and down through scheming unshowned elevating mechanism.In addition, lower electrode 3 can keep set point of temperature through the thermoregulation mechanism (scheming not shown) that is made up of heater that is embedded in inside or temperature measuring portion material etc.
Putting in the courtyard portion of the relative container handling of face 2, for example dispose the upper electrode 4 that roughly is disc-shape with carrying of lower electrode 3.Between upper electrode 4 and container handling 2, insulator 5 is installed in the form of a ring, become electric insulation thereby make between upper electrode 4 and the container handling 2.Below upper electrode 4, for example be formed with a plurality of gases hole 4a that spues.The gas hole 4a that spues is communicated with the top gas supply pipe 6 that is connected upper electrode 4.Processing gas, for example HBr gas, O that gas supply pipe 6 and etch processes are used
2The gas supply source of gas etc. (scheming not shown) is connected.Import to processing gas in the upper electrode 4 from spue hole 4a and in container handling 2, supplying with of a plurality of gases from gas supply pipe 6.
Lower electrode 3 is connected with first high frequency electric source 11 that plasma generates usefulness through lead 10.First high frequency electric source, 11 ground connection.First high frequency electric source 11 can be supplied with the RF power of regulation to lower electrode 3, for example supplies with the RF power that plasma generates the 100MHz of usefulness.Through by this first high frequency electric source 11 to lower electrode 3 supply high frequency electric power, make that the processing space K between lower electrode 3 and upper electrode 4 has been applied in high frequency voltage, in the K of this processing space, can generate the plasma P of handling gas.Wherein, because lower electrode 3 is connected with first high frequency electric source 11, so in this execution mode, lower electrode 3 becomes current electrode, and upper electrode 4 becomes comparative electrode.
In addition, lower electrode 3 is connected through second high frequency electric source 13 of lead 12 and ion introducing usefulness.Second high frequency electric source, 13 ground connection.Second high frequency electric source 13 can be supplied with the RF power that the for example ion lower than the frequency of above-mentioned first high frequency electric source 11 introduced the 13.56MHz of usefulness to lower electrode 3.Through by this second high frequency electric source 13 to lower electrode 3 supply high frequency electric power, and can make the charged particle in the plasma P that in handling space K, generates be induced to wafer W one side.Wherein, also can produce plasma P through the supply of the RF power that undertaken by second high frequency electric source 13.
Plasma-etching apparatus 1 has electrical characteristic adjustment part 20, is used for adjusting the impedance Z of the circuit C1 of upper electrode 4 one sides of seeing from plasma P
C1As shown in Figure 2, in container handling K, generate between the formation zone and upper electrode 4 of plasma P, be formed with sheath (sheath) the region S U of vacuum.In this execution mode, the circuit C1 of upper electrode 4 one sides of seeing from plasma P comprises: sheath zone SU, upper electrode 4, after the lead 24 stated and electrical characteristic adjustment circuit 21 (having merged the zone that is electrically connected with upper electrode 4 and the part of the regional SU of sheath).In addition, impedance Z
C1Being the impedance of this circuit C1, for example is the frequency that generates first high frequency electric source 11 of usefulness with respect to plasma.Wherein, under upper electrode 4 and situation that high frequency electric source is connected, circuit C1 also comprises this high frequency electric source.
As shown in Figure 1, electrical characteristic adjustment part 20 comprises electrical characteristic adjustment circuit 21, impedance detection portion 22 and control part 23.Electrical characteristic adjustment circuit 21 for example is connected with upper electrode 4 through lead 24.For example, as shown in Figure 3, electrical characteristic adjustment circuit 21 for example is made up of with fixed coil 26 grades the variable capacitor 25 as variable element.Can change impedance Z through the capacity of change variable capacitor 25
C1
Impedance detection portion 22 for example can freely load and unload with respect to electrical characteristic adjustment circuit 21 or lead 24, for example, can detect the impedance Z of upper electrode 4 one sides that are connected on the lead 24
C1Numerical value.
Control part 23 can control group Z
C1, for example adjust the variable capacitor 25 that electrical characteristic is adjusted circuit 21, make it reach predefined set point.
Be connected with the blast pipe 30 that is communicated with exhaust gear (scheming not shown) in the bottom of container handling 2.Through blast pipe 30 with being evacuated in the container handling 2, thereby can the inside of container handling 2 be remained on authorized pressure.Wherein, also can be in the two side of container handling 2 outer setting magnet, in container handling, apply magnetic field.In the case, magnet is variable mode and constituting with magnetic field intensity preferably.
Below, the etch processes that the plasma-etching apparatus 1 that uses said structure is carried out describes.At first, in plasma-etching apparatus 1, for example before the beginning etch processes, impedance detection portion 22 is installed for example on lead 24.Through impedance detection portion 22, for example adjust each capability value of the variable capacitor 25 in the circuit 21 and measure impedance Z with respect to electrical characteristic
C1Numerical value.Therefore, the capability value (adjusted value) and the impedance Z of the variable capacitor 25 of electrical characteristic adjustment circuit 21 have for example been grasped
C1Value between dependency relation.According to this dependency relation, in control part 23, set and to make the do not resonate adjusted value of variable capacitor 25 of (resonance series) of circuit C1, for example set impedance Z
C1From resonance point stagger ± 10 Ω are with the such adjusted value of interior setting.Control part 23 is adjusted variable capacitor 25 according to the adjusted value of this setting, with impedance Z
C1Be adjusted into the setting that circuit C1 is not resonated.
Then, as shown in Figure 1, wafer W is moved in the container handling 2, and carried and to place on the lower electrode 3, then, the gases in the container handling 2 are discharged from blast pipe 30, simultaneously, supply with predetermined process gas from the gas hole 4a that spues.At this moment, be maintained at the decompression pressure of regulation in the container handling 2.
Then, for example pass through first high frequency electric source 11 and second high frequency electric source 13, in handling space K, apply high frequency voltage to the RF power of the 100MHz of lower electrode 3 supply plasmas generation usefulness and the RF power that ion is introduced the 13.56MHz of usefulness.Make the processing gaseous plasmaization of handling space K through this high frequency voltage, produce plasma P.Charged particle among this plasma P makes the surface of wafer W be etched attached to the surface of wafer W.After the etching of carrying out the stipulated time, stop the supply of RF power and the supply of processing gas, in container handling 2, wafer W is taken out of, finish a series of etch processes.
Here, in above-mentioned etch processes, to controlled impedance Z
C1Numerical value and the relation between the etch processes result verify.Experiment is to use above-mentioned plasma-etching apparatus 1 under following condition, to carry out, that is, the flow of handling gas HBr is 90cm
3/ min, processing pressure is 0.4Pa (3mTorr), the RF power of 100MHz/13.56MHz is 500/100W.
Fig. 4 is the expression impedance Z
C1And the chart that concerns between the inner evenness of rate of etch (3 σ).H among Fig. 4 representes impedance Z
C1Resonance point.From Fig. 4, can confirm: work as impedance Z
C1When being positioned on the resonance point H, the inner evenness of rate of etch worsens, when making impedance Z
C1When resonance point H staggered, it is good that the inner evenness of rate of etch becomes.Particularly, with impedance Z
C1From resonance point H stagger ± 10 Ω in the time, the inner evenness of rate of etch obtained well really with.
Fig. 5 (a) is the expression impedance Z
C1The chart of the rate of etch of the wafer face when being positioned at resonance point (ER).Fig. 5 (b) is that expression is with impedance Z
C1Stagger+chart of rate of etch during 3 Ω from resonance point.Fig. 5 (c) is that expression is with impedance Z
C1Stagger+chart of rate of etch during 8 Ω from resonance point.
Can confirm from Fig. 5 (a)~(c): make impedance Z
C1Under the situation about staggering from resonance point, rate of etch is significantly improved.In addition, the uniformity of the rate of etch in the wafer face also is improved.
In addition, Fig. 6 (a) is the chart that expression makes the inner evenness (Δ Vdc) of the potential difference among the circuit C1 sheath zone SL (shown in Figure 2) in when resonance.Can estimate out by the caused amount of damage of the etch processes in the wafer surface through the inner evenness (Δ Vdc) of this potential difference.Fig. 6 (b) is that expression is with impedance Z
C1The chart of the inner evenness of the potential difference when resonance point staggers-4 Ω.
Shown in Fig. 6 (a) and (b), can confirm: with impedance Z
C1Under the situation about staggering from resonance point, the inner evenness of the potential difference among the SL of sheath zone is improved, and the damage of etch processes has obtained reduction.
According to above-mentioned execution mode, electrical characteristic adjustment part 20 is set, the impedance Z the circuit C1 of upper electrode 4 one sides that adjustment is seen from plasma P in plasma-etching apparatus 1
C1, make circuit C1 not resonate, thereby, the uniformity of the rate of etch in the wafer W face can be improved.Particularly, through with impedance Z
C1Stagger ± setting of 10 Ω from resonance point, can improve rate of etch, further can also reduce the damage that causes because of etch processes.
In the above-described embodiment, adjust the electrical characteristic of upper electrode 4 one sides through the variable capacitor 25 of electrical characteristic adjustment part 20, thereby can change impedance Z fairly simplely
C1
In the above-described embodiment, be to detect impedance Z
C1In time, just be connected impedance detector 22 on the lead 24, still, also can that kind as shown in Figure 7, in advance impedance detector 22 is installed on the lead 24, with the testing result of impedance detector 22 to control part 23 outputs.In this case, for example, control part 23 is according to the variable capacitor 25 of adjusting electrical characteristic adjustment circuit 21 from the testing result of impedance detector 22, with impedance Z
C1Be controlled at the setting that circuit C1 does not resonate.Thereby, can automatically adjust impedance Z
C1In addition, in etching treatment procedure, for example also can measure impedance Z in real time by impedance detector 22
C1, when because certain is former thereby make impedance Z
C1Numerical value change and situation near resonance point under, control part 23 for example changes the adjusted value of variable capacitor 25, with impedance Z
C1Be modified to the numerical value that circuit C1 does not resonate.Its result can prevent more reliably that circuit C1 from resonating.Therefore, make the inner evenness of etch processes obtain stable the raising.
As described in the above-mentioned execution mode, when the adjustment impedance Z
C1Make under the situation that circuit C1 do not resonate, also can that kind as shown in Figure 2, electrical characteristic is adjusted the reactance X the circuit C2 of circuit 21 1 sides from electrode surface 4a towards the upper electrode 4 of sheath zone SU
C2Be adjusted into negative value.This circuit C2 is the circuit that comprises upper electrode 4, lead 24 and electrical characteristic adjustment circuit 21, reactance X
C2Be the reactance among this circuit C2.
Impedance Z in the general circuit that exists is represented like following formula (1).
Z=R+iX……(1)
(R representes resistance, and X representes reactance.)
In addition, the resonance series of so-called circuit is meant that the numerical value of reactance X is 0 o'clock resonance.
For the zone of the sheath between plasma P in the plasma-etching apparatus 1 and the upper electrode 4 SU; Because capacity property, be that the numerical value of reactance is always negative electrically; So, through the reactance X the circuit C2 that electrical characteristic is adjusted circuit 21 directions from electrode surface 4a
C2Be adjusted into negative value, and can the reactance of the entire circuit C1 of electrode surface 4a one side of seeing from plasma P always be maintained negative value.In view of the above, because the reactance of circuit C 1 can not become 0, so, its resultant impedance Z
C1Adjusted, circuit C1 is not resonated.In the case, irrelevant with the plasmoid of handling in the K of space, can not cause the generation of resonance on the principle.Wherein, always with the reactance X of circuit C2
C2When being maintained negative value, use the electrical characteristic adjusting mechanism.As this electrical characteristic adjusting mechanism, preferably electrical characteristic is adjusted circuit 21.Through the electrical characteristic (reactance) in this electrical characteristic adjusting mechanism is adjusted into expectation numerical value, and with the reactance X among the circuit C2
C2Always be maintained negative value.From this point, this electrical characteristic adjusting mechanism both can be the variable element with 25 1 types in variable capacitor as electrical characteristic adjustment circuit 21, also can be the structure that only is made up of retaining element.
In this example, for example, as long as with reactance X
C2Stagger and get final product for negative value more than 50 Ω.In the case, because the reactance of circuit C 1 can not become 0, so, can prevent the resonance of circuit C1 reliably, thereby can make the action of plasma-etching apparatus 1 stable.Therefore, for example, can reduce the action deviation (machine error) that produces between a plurality of plasma-etching apparatus.
For at the plasma-etching apparatus 1 described in the above execution mode, be to supply with two kinds of RF powers to lower electrode 3, still, also can only supply with a kind of RF power that plasma generates usefulness to lower electrode 3.
In addition; In the above execution mode; To lower electrode 3 one side supply high frequency electric power, still, also can supply with to lower electrode 3 with replacement to the RF power of upper electrode 4 one sides supply plasma generation usefulness; Also can adjust with respect to the impedance the circuit of the lower electrode 3 one sides frequency of this RF power, that see from plasma P, this circuit is not resonated.In the case, for example, electrical characteristic adjustment circuit 21 is set at lower electrode 3 one sides, and electrical characteristic adjustment circuit 21 is connected with lower electrode 3.
And, also can be to both sides' supply high frequency electric power of upper electrode 4 and lower electrode 3, the impedance the circuit of each counter electrode that adjustment is seen from plasma P is not so that each circuit resonates.In the case, as shown in Figure 8, upper electrode 4 all is connected with electrical characteristic adjustment circuit 21 with lower electrode 3 both sides.For the electrical characteristic adjustment circuit 21 that is connected with upper electrode 4, its adjustment is with respect to the impedance the circuit of upper electrode 4 one sides frequency, that see from plasma P of the RF power of supplying with to lower electrode 3 one sides.For the electrical characteristic adjustment circuit 21 that is connected with lower electrode 3, its adjustment is with respect to the impedance the circuit of lower electrode 3 one sides frequency, that see from plasma P of the RF power of supplying with to upper electrode 4 one sides.
In above execution mode; Adjustment is with respect to the impedance in circuit frequency, counter electrode one side of the RF power of supplying with to current electrode; So that circuit does not resonate; But, also can adjust impedance, so that circuit does not resonate with respect to other high frequency frequencies of in handling space K, propagating and existing.In the high frequency in this example, comprise higher harmonics that supply because of RF power etc. produces etc.In the case, for example as shown in Figure 9, be connected with lower electrode 3 one sides of high frequency electric source 11,13, be provided with the electrical characteristic adjustment part 20 identical with above-mentioned execution mode.For example, on the lead 10,12 that connects lower electrode 3 and each high frequency electric source 11,13, be connected with electrical characteristic adjustment circuit 21, impedance detection portion 22 respectively.
In addition, for example adjust the impedance Z the circuit C3 of lower electrode 3 one sides of seeing from plasma P through electrical characteristic adjustment part 20
C3, the circuit C3 of lower electrode 3 one sides is not resonated with respect to being present in the high frequency of handling the regulation in the K of space.Shown in figure 10, the circuit C3 of lower electrode 3 one sides of seeing from plasma P comprises: sheath zone SL, lower electrode 3, lead 10,12, high frequency electric source 11,13, impedance detection portion 22 and electrical characteristic adjustment circuit 21.Impedance Z
C3Being the impedance among its circuit C3, for example, is the impedance with respect to the high frequency that in handling space K, produces.In addition, in Figure 10, circuit C4 comprises lower electrode 3, lead 10,12, and high frequency electric source 11,13, impedance detection portion 22 and electrical characteristic adjustment circuit 21, in addition, reactance X
C4It is the reactance among its circuit C4.
More particularly, for example, through electrical characteristic adjustment part 20, for making impedance Z
C3Stagger significantly so that circuit C3 does not resonate from resonance point, for example make the reactance X of circuit C4
C4Staggering on the negative value more than 50 Ω.Therefore; For example, in any case in the treatment state plasma-etching apparatus different, can with respect to high frequency circuit C3 be resonated in high frequency electric source one side with treatment conditions; In all plasma-etching apparatus 1, Cement Composite Treated by Plasma is stably carried out.Its result makes unbalanced being reduced between the device of Cement Composite Treated by Plasma.
In addition, more than in the execution mode put down in writing, upper electrode 4 also can be connected with DC power supply.Wherein one is for example shown in Figure 11.Upper electrode 4 is electrically connected through low pass filter 32 and variable DC power supply 31.The variable power supply 31 of this moment also can be a bipolar power supply.Variable DC power supply 31 can carry out the switch power supply through relay switch 33.The polarity of variable DC power supply 31, current value, magnitude of voltage, with the switch of relay switch 33 all by 34 controls of direct voltage control part.For low pass filter 32,, preferably constitute by LR filter or CL filter in order to hinder the high frequency waves that the first and second high frequency waves power supplys 11,13 are sent.
Then, apply the specified polarity and big or small direct voltage that is provided by variable DC power supply 31 to upper electrode 4.Thus, make the deposit sputter of adsorbing on the surface of upper electrode 4, can obtain making the effect of the cleaning surfaces of upper electrode 4.In addition; The plasma P that forms in the container handling 2 is dwindled; Because the actual effect residence time (residence time) on the wafer W reduces,, can access and make organic mask of photosensitive film etc. be difficult to etched effect so suppress the decomposition of the processing gas of fluorocarbon system.And, because near the electron irradiation that upper electrode 4, generates is on wafer W, so obtain that mask on the upgrading wafer W is formed and the effect of the disappearance of elimination photosensitive film.
And; Because with electrical characteristic adjustment part 20 combinations of the plasma etching apparatus 1 of explanation in the above-described embodiment; So can obtain following effect simultaneously: promptly; Effect when upper electrode 4 applies direct voltage, and, the impedance Z on the circuit C1 of upper electrode 4 one sides of seeing from plasma P adjusted through electrical characteristic adjustment part 20
C1, make loop C1 not resonate, thereby improve the effect of the rate of etch in the wafer W face.
When be applied in upper electrode 4 last times, the formation zone of plasma P shown in Figure 2 and the further thickening of the zone SU of the sheath between the upper electrode 4 than direct voltage in the also big negative polarity of the self-deflection voltage Vdc of the surface of upper electrode 4 generation.Impedance Z on the circuit C1 of upper electrode 4 one sides of seeing from plasma P thus,
C1Change (diminishing), with respect to the impedance Z of this variation
C1Adjust and make circuit C1 not resonate, the effect of the rate of etch in the wafer W face that so just can be improved.
Wherein, shown in figure 12, variable DC power supply 31, low pass filter 32, relay switch 33 are arranged on the GND next door of electrical characteristic adjustment circuit 21, also can obtain same effect shown in figure 11.
In addition; As shown in Figure 8; In plasma-etching apparatus 1, variable DC power supply 31, low pass filter 32 and relay switch 33 also can that kind shown in figure 13 be set on upper electrode 4 to both sides' supply high frequency electric power of upper electrode 4 and lower electrode 3.
In addition; Shown in figure 14; Both sides to upper electrode 4 and lower electrode 3 provide in the plasma etching apparatus 1 of RF power, and above-mentioned variable DC power supply 31, low pass filter 32 also can be obtained identical effect with GND one side that relay switch 33 is arranged on electrical characteristic adjustment circuit 21.Wherein, also can replace, but apply direct voltage to upper electrode 3 one sides to upper electrode 4 one sides.In addition, also can apply direct voltage to the both sides of upper electrode 4 and lower electrode 3.
In the described in the above-described embodiment plasma-etching apparatus 1, upper electrode 4 is with discoid and by integrated, still, also can be divided into a plurality of electrode part, and its arbitrary electrode part is provided with electrical characteristic adjustment part 20 relatively.Figure 15 is the figure of the said example of expression, and upper electrode 40 is divided into the 40a of medial electrode portion and centers on the 40b of lateral electrode portion of the ring-type in its outside.Between 40a of medial electrode portion and the 40b of lateral electrode portion, be folded with the insulator 40c of ring-type.The 40a of medial electrode portion ground connection, the 40b of lateral electrode portion for example is connected on the electrical characteristic adjustment circuit 21 through lead 24.Wherein, the structure of other parts is identical with the plasma-etching apparatus 1 of above-mentioned execution mode.
In addition, when carrying out etch processes, adjust the impedance in this circuit, make and do not resonate from the circuit of the 40b of lateral electrode portion one side that plasma P is seen through electrical characteristic adjustment circuit 21.In the case, for example, be improved at the inner evenness of the etch processes of carrying out with the periphery position of the wafer W of the 40b of lateral electrode portion subtend.So, can improve the etching characteristic of the established part in the wafer face.Wherein, in this example, also can electrical characteristic adjustment part 20 be arranged on the 40a of medial electrode portion, adjust the impedance in the circuit of the 40b of lateral electrode portion one side and the 40a of medial electrode portion one side respectively.Therefore, can improve each regional etching characteristic of wafer W respectively.In addition, can on the 40b of lateral electrode portion, electrical characteristic adjustment part 20 be set yet, and only on the 40a of medial electrode portion, be provided with.
In the above execution mode; Adjust the impedance in this circuit; Make and not resonate, still, change an angle from the circuit of seeing with the plasma P of counter electrode one side of current electrode subtend; To reach maximum in order making, also can to adjust the electrical characteristic of electrode one side of seeing from plasma P from handling the current value that space K flows into the electric current of electrode.In this case, for example shown in figure 16, in upper electrode 4 one sides electrical characteristic adjustment part 50 is set as the counter electrode of plasma-etching apparatus 1.Electrical characteristic adjustment part 50 for example mainly is made up of electrical characteristic adjustment circuit 51, current value test section 52 and 53 of control parts.
Electrical characteristic adjustment circuit 51 is connected with upper electrode 4 through lead 24, and is identical with the electrical characteristic adjustment circuit 21 described in the above-mentioned execution mode, has variable capacitor 25 and fixed coil 26.Can adjust the current value of the electric current that flows into upper electrode 4 through the capacity that changes variable capacitor 25.Current value test section 52 for example is connected with lead 24, detects the current value of the electric current B that flows into upper electrode 4, and can be with its result to control part 53 outputs.In control part 53, be set with the lowest high-current value of the electric current B that tries to achieve in advance.Control part 53 is adjusted the variable capacitor 25 of electrical characteristic adjustment circuit 51 according to the testing result of current value test section 52 and is controlled, and the feasible current value that flows into the electric current B of upper electrode 4 does not reach lowest high-current value.Wherein, the structure of other parts of this routine plasma-etching apparatus 1, identical with above-mentioned execution mode, the Therefore, omited explanation.
In addition, when carrying out etch processes, detect the current value of the electric current B that flows into upper electrode 4 in real time by current value test section 52.Adjust variable capacitor 25 by control part 53 according to the testing result of current value test section 52, make the current value of electric current B not reach lowest high-current value.If adjust like this so that electric current B does not reach maximum; The circuit of then above-mentioned upper electrode 4 one sides does not resonate; So,, can improve the inner evenness of etch processes with the described situation that circuit is not resonated through the adjustment impedance is identical in the above-described embodiment.Particularly; Be adjusted at current value under the situation more than 1/2 of the lowest high-current value that flows into upper electrode 4 electric current B, that is, and under the situation of current value<lowest high-current value of 1/2≤electric current B of lowest high-current value; With in the above-described embodiment described with impedance from resonance point stagger ± 10 Ω are identical with interior situation; Can improve rate of etch, and, the damage that causes because of etch processes can also be reduced.
In this example; For example, both can be under the situation of upper electrode 4 supply high frequency electric power, the electrical characteristic of lower electrode 3 one sides that adjustment is seen from plasma P; Do not reach maximum so that flow into the current value of the electric current B of lower electrode 3; Also can adjust the electrical characteristic on each electrode, not reach maximum so that flow into the current value of both electric currents of upper electrode 4 and lower electrode 3 under the situation of upper electrode 4 and lower electrode 3 both supply high frequency electric power.
In addition, in this example, any at least one of above-mentioned upper electrode 4 and lower electrode 3 can be connected with the variable current power supply, and at least one that can be in top power supply 4 and bottom power supply 3 applies direct voltage.
In addition; Described in above-mentioned execution mode; Also can upper electrode 4 be divided into a plurality of electrode part, at least one of this divided electrode part, electrical characteristic adjustment part 50 be set and adjust, not reach maximum so that flow into the current value of the electric current of this electrode part.For example, the 40b of lateral electrode portion with respect to upper electrode shown in Figure 10 40 also can be provided with electrical characteristic adjustment part 50.
More than, an example of execution mode of the present invention is illustrated, still, example that the present invention is not limited thereto also can adopt variety of way.For example, in this execution mode, the present invention is applicable to plasma-etching apparatus 1, but the present invention goes for also carrying out for example carrying out the plasma processing apparatus that film forming is handled in the plasma processing apparatus of the processing of wafers beyond the etch processes.In addition, the handled substrate of plasma processing apparatus of the present invention is not limited to wafer, also can be other substrates such as substrate of organic EL substrate, FPD (flat-panel monitor) usefulness.
Practicality on the industry:, in the plasma processing apparatus of substrate, be useful during the uniformity of the processing substrate in improving real estate according to the present invention.