JP2728010B2 - Plasma processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method.
In particular, processing is performed by alternately performing etching and deposition.
The present invention relates to a plasma processing method suitable for
You. [0002] 2. Description of the Related Art As the miniaturization of semiconductor devices progresses,
Road pattern dimensional processing system and low damage processing method
It is becoming an important technical issue. Especially submicron
In the element in the region, the element structure is limited due to the limitation of the chip area.
The structure is becoming three-dimensional. For this reason, compared to the processing dimension width
Processing depth ratio, that is, film type with large aspect ratio
It is required to process with high accuracy. [0003] As a conventional technique for solving such a demand,
Is described in Japanese Patent Publication No. 60-50923.
There is something like the above. This is Si or Poly-Si
In the case of etching of
SF contributing to the etching action₆Protective film of gas and silicon nitride
That contribute to the formation of N_TwoMix gas and other gases
And the composition and concentration of the processing gas during the etching process.
Change it periodically. This allows the etching process and nitriding
The process of forming a silicon protective film is alternately repeated,
So that etching can be performed quickly and with high dimensional accuracy.
I have. On the other hand, the voltage applied to the electrode is changed.
The Japanese Patent Publication No. 61-41132
And Japanese Patent Application Publication No. 61-13625.
Can be These conventional techniques change the voltage applied to the sample.
Then, the plasma processing is performed. [0005] The former of the above prior art is
Etching process by changing plasma gas composition and concentration
The state of the plasma each time
Will change. For this reason, the gas composition and concentration
Is changed from the previous plasma state to a new plasma state
State. That is, the remaining ions and radicals
It is necessary to exhaust. However, the processing vessel has some
Switching time of plasma state takes time due to internal volume
Therefore, there is a problem that the entire processing time becomes longer. Ma
Also, if you try to improve this a little, you can reduce the exhaust time.
In order to reduce the size, the exhaust device becomes large. Also at the same time processing
It is necessary to control the displacement during
In addition, the equipment and control technology for that are complicated. On the other hand, the latter is the incident energy of ions in the plasma.
Controls the energy and simply controls the etch rate and selectivity.
This is to improve the plasma characteristics. An object of the present invention is to provide a fine pattern and
A plasm that can perform etching with a high pect ratio
To provide a processing method. [0008] Means for Solving the Problems The present inventors conducted various experiments.
For the first time, we gained a perspective on the invention. So
This is as follows. Sample to be etched
Having a component that reacts and a component that forms a deposited film
Plasma of various component gases under specified plasma conditions
You. An acceleration voltage is applied to the ions in the plasma,
The test was performed using a plasma that was turned on to the sample.
Processing fees. At this time, change the value of this acceleration voltage
Then, the etching action becomes dominant due to the reaction with the workpiece
There is a potential that occurs and a potential where the sedimentation action predominates
I understood. In addition, the potential of etching and deposition
It has been found that there is a potential that balances the action. Below,
Is called "critical potential."
Akira forms components and deposited films that react with the material to be etched.
A mixed gas having a component and a critical potential
Is used as an etching gas, and an etching gas
Using the ECR of microwave to reduce to the order of 0.01 Torr
For the process of turning into plasma under pressure and for the material to be etched
The acceleration voltage for accelerating ions in the plasma
To change the material to be etched.
Alternately repeating film formation andBy film formation
Etching of the protective film on the side wall of the formed pattern
Sometimes removingFine pattern and large aspect ratio
This is achieved by using
You. [0009] The gas having a critical potential is reduced to the order of 0.01 Torr.
Microwave plasma using ECR discharge under low pressure
Causes ions in the plasma to accelerate toward the sample
Change the acceleration voltage to be applied across the critical potential
do itAnd the plasma is generated under low pressureIs
Ions in plasma are pulled into the sample with a small acceleration voltageMida
Fewer imagesAnd the acceleration voltage is higher than the critical potential.
When etching is large, the etching effect is predominant on the sample.
When the accelerating voltage is lower than the critical potential,
Product action occurs predominantly,These etching and film formation
Alternating pattern sidewalls formed by film formation
Since the protective film on the surface is removed while etching,
Without reducing the pattern widthFine pattern and ass
Can process materials to be etched with large pect ratio
You. [0010] 1 to 6 show an embodiment of the present invention.
This will be described below. FIG. 1 is a schematic diagram of a micro unit utilizing ECR discharge.
Shows a microwave plasma processing apparatus, in this case, an etching apparatus
It is. The upper opening of the vacuum processing vessel 4 is
An electric tube 1 is provided. Shown in the lower part of the vacuum processing container 4
An exhaust unit 3 connected to a vacuum exhaust device
You. In the vacuum processing container 4, a wafer 6 serving as a sample
There is provided an electrode 5 having a sample stage 5a on which the sample is placed. Release
A discharge space 7 is formed above the sample stage 5a in the electric tube 1.
You. On the upper part of the discharge tube 1, there is a conductor surrounding the discharge tube 1.
A wave tube 9 is provided. At the end of the waveguide 9, in this case:
Magnetron 8 that emits 2.45 GHz microwave
Is provided. An outer peripheral portion of the discharge tube 1 is provided via a waveguide 9.
An electromagnetic coil 10 is provided. A discharge space 7 is provided on the side of the vacuum processing vessel 4.
A gas introduction unit 2 for supplying an etching gas is provided.
is there. A mass flow controller 18 is provided in the gas introduction section 2.
A gas source (not shown) is connected to the apparatus. The outer periphery of the electrode 5 is insulated from the electrode 5,
The end is located near the periphery of the sample table 5a, and the other end is grounded
A ground electrode 11 is provided. Electrode 5 has matching
Connected via box 12. In this case, 13.56
High frequency power supply 13 oscillating high frequency of MHz
Connected to DC power supply 15 connected via filter 14
It is. The other ends of the high-frequency power supply 13 and the DC power supply 15
Each is grounded. The DC power supply 15 has an output voltage control device.
The output voltage controller 16 is connected to the
The waveform controller 17 is connected. Note that the matching button
In this case, the box 12 is configured by a capacitor coupling.
It has been done. Low-pass filter 14 is high-frequency power supply 13
These high-frequency voltages are cut off. The mass flow controller 18 is not shown.
Control the etching gas from the gas source to a predetermined flow rate,
The etching gas is sent into the discharge space 7. In the discharge space 7
Is depressurized and exhausted by an exhaust device (not shown) to a predetermined pressure.
Held in force. In this case, the etching introduced into the discharge space 7
Means for converting the magnetizing gas into plasma are generated by the magnetron 8
And a magnetic coil 10. Etching gas in discharge space 7
Is given by magnetron 8 and electromagnetic coil 10
Plasma by ECR discharge caused by the action of electromagnetic field
Is done. Also, in this case, the ions in the plasma
A means for applying incident energy to Eha 6,
In the case of (1), the means for generating the accelerating voltage on the sample stage 5a is high.
It comprises a frequency power supply 13 and a DC power supply 15. Place wafer 6
A high-frequency power supply from a high-frequency power supply 13 is
Voltage and a DC voltage from the DC power supply 15 are applied. Trial
Match composed of capacitor coupling on the platform 5a
To apply a high-frequency voltage through the
As a result, a high-frequency voltage is applied to the sample stage 5a while floating in a DC manner.
As a result, a DC bias voltage is generated. This DC bias
Depending on the voltage, ions in the plasma may be
That is, it is drawn into the wafer 6 side. Also, the sample table 5a
By applying a DC voltage, the direct voltage generated on the sample stage 5a is reduced.
The value of the current bias voltage is adjusted. This DC bias voltage
The pressure in this case is the acceleration voltage that accelerates the ions. Further, in this case, it is generated on the sample stage 5a.
For switching the acceleration voltage value across critical potential
Are the output voltage controller 16 and the output waveform controller 17
Consisting of The output voltage control device 16 is a DC power supply of the DC power supply 15.
Control the pressure value. The output waveform controller 17 controls the output voltage.
Timing of changing DC voltage value controlled by device 16
Control. This timing is periodically controlled in this case.
Is controlled. In this case, the wafer 6 is placed on a Si substrate.
A polysilicon layer, which is a wiring forming material,
It is. This etching equipment uses etching gas.
In this case, sulfur hexafluoride (SF₆) And trichloro
Trifluoroethane (C_TwoCl_ThreeF_Three: Product name Freon-11
Using the mixed gas of 3), the polysilicon layer of the wafer 6 is
It is to be etched. Next, the etching configured as described above is performed.
By means of the apparatus, both components of the etching gas, namely S
F₆And C_TwoCl_ThreeF_ThreeAnd the same plasma shape for
Under the conditions (microwave power: 400 W, gas flow rate: 70
SCCM, pressure: 0.01 Torr, high frequency power: 10
0W) to convert the gas into plasma and apply it to the sample stage 5a immediately.
In the experiment when the bias current was changed,
This will be described with reference to the drawings. In the graph of FIG.
Take the deposition rate down, and take the DC
Take the ias voltage. As is apparent from FIG.₆Is DC
Etching phenomenon always regardless of the magnitude of bias voltage
And the etching speed increases as the DC bias voltage increases.
The degree also increases. This is SF₆But in plasma
Divided into F components, reactive ion species and free radio
F ions and F radicals in the F species
The DC bias voltage.
Reacts with the material to be etched, polysilicon
And SiF_FourA volatile reaction product is formed
When the DC bias voltage is increased,
F ions in plasma as well as F ions on sample surface
Is incident on the sample, and the reaction with F ions increases.
In addition, F ions are added to F radicals located near the sample surface.
Collision causes increased contact between F radical and polysilicon
Thus, the etching rate is increased. On the other hand, C_TwoCl_ThreeF_ThreeIs the DC bias voltage
In the range where is small, a deposition phenomenon occurs and the DC bias voltage is
An etching phenomenon occurs in a large range. this is,
C_TwoCl_ThreeF_ThreeIs the component of C, Cl and F in the plasma
And these components are a polymer of C or (CFx)
Reaction products of n, CxFy, CClxFy, CxCly
And deposits of the remaining Cl and F
Because the ingredient exists as an etchant,
As described above, the component of F is opposite to that of polysilicon as described above.
Correspondingly SiF_FourTo form volatile reaction products,
The components of Cl as chants are similarly reactive ion species and
Reacts with polysilicon in the form of free radical species and S
iCl_FourTo form volatile reaction products. here,
With or without DC bias voltage,
In addition, a film-forming species and an etchant
Formed in the plasma while the bias voltage is acting on the plasma
Deposits adhere to the sample surface and
The incidence of ions in the plasma occurs simultaneously. DC bike
In the range where the assault voltage is small, the ion
The incidence of light on the surface of the sample to be etched
Deposit adheres to the surface of the material to be etched and in the plasma
Can no longer contact with the etchant, causing sedimentation
I will. In the range where the DC bias voltage is large,
The incidence of ions in the plasma increases,
Even if deposits adhere to the material surface,
Reactive ions as an etchant are incident on the surface,
While removing the surface of the material to be etched,
It collides with the load and gives energy to the deposit,
Decompose to the proper state to prevent adhesion of sediment
Then, the etching action proceeds. What
At this time, the free etchant near the sample surface
Reactive ions that are etchants for radicals and
Some of the ions of the film-forming species collide with free radicals
Gives energy and promotes reaction with the material to be etched
Act like Also, C_TwoCl_ThreeF_ThreeIs just deposited on the boundary
Critical potential (V₀)have
You can see that. Note that this critical potential is a predetermined plasma
The gas is turned into a plasma under the
Deposition phenomenon and etching phenomenon are reversed when
Potential, which was first seen by the inventor's experiments.
It has been brought out. This indicates the following. C_TwoC
l_ThreeF_ThreeAnd plasma etching
The effect and the effect are concurrent. At this time, the voltage is applied to the sample stage 5a.
Deposition if the DC bias voltage is lower than the critical potential
Action works dominantly. Further, the direct voltage applied to the sample stage 5a is
Current bias voltage is increased within a range smaller than the critical potential.
When the DC bias voltage increases,
The ions in the matrix are accelerated, and the etching action gradually increases
The superiority of sedimentation gradually declines. DC bias voltage
If the pressure increases beyond the critical potential,
The ions in the matrix are accelerated and the etching action is more than the deposition action
Acts predominantly, and its etching action gradually increases.
You. When the DC bias voltage is equal to the critical potential,
Is in a state where the deposition action and the etching action are balanced.
You. Further, the SF having no critical potential as described above
₆And C having a critical potential_TwoCl_ThreeF_ThreeMixed gas (1:
A similar experiment was performed using 9). This result
The curve was as shown by the broken line in FIG. This dashed curve
As is clear from FIG.₀’
Exists and the critical potential V₀’Smaller DC bias voltage
In this case, the sedimentation action predominates and the critical potential V₀Greater than
At DC bias voltage, the etching effect is dominant
You. Moreover, when this mixed gas is used, the C_Two
Cl_ThreeF_ThreeEtching rate is faster than when using
It can be seen that the voltage largely depends on the current bias voltage. to this
Therefore, this mixed gas depends on the bias voltage of the etching rate.
It turns out that it can be used as a highly viable etchant
Was. Next, a mixed gas having such characteristics is used.
In the case of performing the etching process using
FIG. 6 will be described. First, the mixed gas is supplied to the critical potential V₀Greater than ’
Threshold voltage V₁’For high aspect ratio poly
When the silicon film is etched, as shown in FIG.
As shown, the undercut C becomes larger and dimensional accuracy is secured.
Can not do it. Here, 19 is a photoresist,
Reference numeral 20 denotes polysilicon, and reference numeral 21 denotes a Si substrate. Therefore, as shown in FIG.
DC voltage superimposed on the played high-frequency voltage as an output voltage controller
16 and the output waveform controller 17 to control the DC
The bias voltage is t₁The second is the critical potential V of the mixed gas₀Greater than ’
Ki V₁(Negative potential) and t_TwoCritical potential V for seconds₀'Than
Small V_Two(Negative potential)
I made it. Time t₁DC bias voltage is large for seconds
Therefore, while accelerating the ions in the plasma toward the wafer 6,
Etching can be performed. This allows you to compare
Etching can be performed. But free radio
Due to the influence of culls, a slight under
Cut C₀Occurs. This undercut C₀The size of
About 1/5 to 1/10 of the vertical etching amount d.
Was. Time t₁Is undercut C₀Is within the allowable range.
Set within the box. Time t_TwoDC bias voltage is critical for seconds
Potential V₀’Smaller than
Wear. This stops the progress of the etching,
6 Plasma polymer begins to be deposited on the entire surface, polysilicon 2
A protection film is formed on the pattern 0 side wall. After the protection film is formed, a large DC
Bias voltage V₁To the sample table 5a and perform etching.
Now. This large DC bias voltage V₁Accelerated by
The ions in the plasma are incident on the wafer 6 perpendicularly.
You. Thereby, it is formed by the photo resist 19
Film deposited on the bottom of the patterned polysilicon 20
Are quickly removed by the ion sputtering action,
The etching of the bottom of the pattern of the silicon 20 is exposed.
proceed. In addition, on the pattern side wall surface of the polysilicon 20
The deposited protective film has a very small physical energy
-Free radicals and protection due to radical attack
It is gradually removed by a chemical reaction with the components of the film.
Therefore, the time t for depositing the protective film is_TwoIs the time t₁Between
The patterning of the polysilicon 20 is performed even if the
It is set so that the protective film deposited on the side wall surface remains.
The time t set in this manner is₁, T_TwoComes out in advance
It is stored in the force waveform controller 17 and automatically turned off.
I have to change it. Thus, the etching process and the deposition process
Process, that is, by alternately repeating the film forming process.
And high aspect ratio polysilicon as shown in FIG.
The film can be processed with high dimensional accuracy. Note that, as shown in FIG.
Ass voltage V₁The value of is the charge-up of ions to the sample
1/1 of the total amplitude value Vpp of the high-frequency voltage to prevent
It is smaller than 2. This allows for high etching rates
Damages the device formed on the sample
To perform the etching without
This is because the magnitude of the flowing voltage is restricted. That is, the DC bias voltage value (negative voltage)
Greater than 1/2 of the total amplitude value Vpp of the high frequency voltage.
Then, the sample is always at a negative potential and the positive ion
Is attracted and charged. With this,
Are positive ions (reactive ions) in the plasma
Will not reach the fee. As a result, the etching rate of the sample
Is significantly reduced. Also, the charging potential at this time
Is large, the deterioration of the gate of the device formed on the sample and
This is because it causes destruction. For this reason, in the present embodiment, the total oscillation of the high-frequency voltage is
A negative DC voltage smaller than 1/2 of the width value Vpp is applied to the sample stage 5.
a, and a part of the waveform of the high-frequency voltage becomes a positive potential
So that electrons in the plasma are attracted by this positive potential.
To neutralize the positive ions charged on the sample.
ing. Further, this charge-up problem is solved.
To do so, Japanese Patent Publication No. 56-37311
As detailed in the issue, the transmission frequency of the high-frequency voltage is
It needs to be about 100 kHz or more. Above the transmission frequency
There is no particular restriction on the limit, but it is generally commercially available
If an oscillator is used, oscillation up to about 27 MHz
The frequency is appropriate. As described above, according to the present embodiment, the high-frequency power supply 1
3 applies a high frequency voltage to the electrode 5
The DC bias voltage generated on the sample stage 5a
These DC voltages are superimposed, and the DC via
Output voltage control device 16 and output waveform control device
By changing the critical voltage across with 17
Do not change the plasma generated in the electrical space 7
In other words, without switching gas supply,
Etching and deposition, that is, film formation, is performed on
Since they can be performed by each other, switch the gas type
Etching the sample by alternately performing etching and deposition
There is no gas replacement time compared to conventional technology
No, at least it's time to replace gas
This has the effect of shortening the processing time. For example, a book
The same volume (20,000 cm) as in one embodiment^Three) Vacuum
In the processing vessel, use an exhaust device with an exhaust capacity of 500 l / sec.
And supply 70 SCCM gas into the vacuum processing vessel
From the state where the force is maintained at 0.01 Torr, the gas type is
Time required to switch to the above state
Requires about 10 seconds, and the number of gas type switching
The effect increases as the number increases. Also paraphrase
If it is necessary to switch gas at high speed as before
Because there is no exhaust system, the exhaust device can be downsized. In addition, gas type
Since there is no pressure control or switching control by switching,
Equipment and control techniques are simplified. The output voltage controller 16 is controlled to
A DC bias voltage higher than the ground potential is applied to the sample stage 5a.
As a result, the wafer 6 is etched,
DC bias voltage smaller than
By this, a protective film can be deposited on the wafer 6, and
In addition, the output waveform controller 17 is controlled to set the critical potential.
The timing of changing the value of the DC bias voltage
Since the switching is performed, the etching side surface of the wafer 6 is covered with a protective film.
Stepwise etching while protecting, pattern width
Processes materials to be etched that are deeper or higher than
can do. Further, a microwave program utilizing ECR discharge is used.
Because it is processed by plasma, 0.01 Torr level
Plasma can be generated under low pressure
Ions in the plasma are pulled into the wafer 6 with a small acceleration voltage
Anisotropic etching with less damage
To process the material to be etched with a fine pattern
Can be. As a result, the fine pattern
Of etched material with high aspect ratio
can do. Further, the etching waveform is controlled by the output waveform controller.
Switching time between etching and deposition, and
Ensure that the undercut of the etching material is within the tolerance
Set the time, and during deposition, perform etching during the next etching process.
When the film thickness is large enough to leave the protective film on the side
Because it is between, it is possible to perform processing with good dimensional accuracy
it can. In addition, plasma generation utilizing the action of an electromagnetic field
Provided by raw means, high frequency voltage and DC voltage
DC bias voltage applying means, that is, an accelerating voltage applying means
Since it is independent of the stage,
However, the state of plasma generation, that is,
The states of protons, ions and free radicals do not change,
Etching can be performed while the light intensity is stable.
Easily determine the end point of etching by emission spectroscopy.
Lick A high frequency power supply 13 is connected to the sample stage 5a.
Control the DC voltage of the DC power supply 15
The DC bias voltage is controlled by the high frequency generated from the high frequency power supply 13.
Since it is less than half of the total amplitude of the frequency voltage, insulation
Or charge is accumulated in the sample even if the sample has an insulating film
No, lowering of etching rate and deterioration of gate part of device
Alternatively, etching without destruction can be performed. Ma
In addition, the lower layer MOS gate is formed by the etching method of this embodiment.
When etching a sample with an element structure
But also damage such as breakdown voltage and destruction of gate
Did not. Note that microwaves are used as in the present embodiment.
Plasma treatment to discharge by ECR method used
In the device, the ion sheath width is generally about 0.1 mm
Degrees. Required for ions to pass through this ion sheath
Time (ti) varies slightly depending on the type of ion.
But generally 1 to 4 × 1/10⁷On the order of seconds. Against this
13.56 MHz commonly used for industrial use
The half cycle time (tRF) of the high-frequency voltage waveform is 3.
7 × 1/10⁸Seconds. For this reason, 13.56 MHz
At high frequency voltages, the ions pass through the ion sheath
And cannot follow. Therefore, this one embodiment
By generating a negative DC bias voltage like
To accelerate the ions. A person using such a DC bias voltage
In particular, the method is such that conduction with the electrode 5 such as a Si or metal film can be obtained.
This is effective when processing materials that are not suitable. Also like this
The method using DC bias voltage is effective only for high
Frequency half-cycle time tRF and the ion
The sheath passage time ti is tRF <ti , The frequency of the high-frequency power supply 13
Is 2 MHz (tRF = 2.5 × 1/10⁷Second)
This means that if the frequency is low, the AC voltage waveform
Are also accelerated by the ions,
Therefore, the effect of superimposing a DC voltage on the electrode 5 is weakened.
I will. In the case where the sample is conductive,
Is a DC power supply 1 except for the high-frequency power supply 13 of the present embodiment.
Alternatively, a plasma processing apparatus controlled by only 5 may be used. Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In FIG. 7, the same reference numerals as in FIG.
One member is shown. The difference between this figure and Fig. 1 is that
In this case, a high frequency of 385 KHz
The point is that only the power supply 23 is used. The high frequency power supply 23
Connected to electrode 5 via matching box 22
You. In this case, the matching box 22 is connected to one end of the circuit.
Are grounded, and the electrode 5 is DC grounded.
It is. The high-frequency power supply 23 has output voltage control means 24
Is connected. The output voltage control means 24 includes a high frequency power supply 23
As shown in FIG. 8, the waveform of the high-frequency voltage output from
Time t_ThreeDuring the period, the total amplitude of the high-frequency voltage is V_ThreeSo that
Next time t_FourDuring the period, the total amplitude of the high-frequency voltage is V_FourTona
Control so that The plasma processing apparatus configured as described above,
In this case, 50 nm is deposited on the Si substrate by the etching device.
Polysilicon and photoresist through a thin oxide film
Of the above-described embodiment with respect to the configuration wafer 6a in which
Etching rate and high frequency of polysilicon under the same conditions as
The output voltage of the power supply 23, that is, the relationship with the acceleration voltage is adjusted.
As a result, the same tendency as in FIG. 2 occurred. That is, the frequency 2 by the high frequency power supply 23
MHz or less (385 kHz in this case)
The sample is applied to the sample stage 5a, and ions are sufficiently added to the AC voltage waveform.
And the strength of the AC voltage, that is, the AC voltage
By changing the total amplitude of
As described above, the etching action is dominant, and the deposition action is
And whether it is etching or deposition
A state that did not progress appeared. Therefore, the output voltage control means 24
To control the output voltage of the high frequency power supply 23 as shown in FIG.
Then time t_ThreeDuring the period, the high-frequency voltage V higher than the critical potential_Three
Is applied to the electrode 5 to etch the polysilicon.
U. Next, time t_FourHigh frequency lower than the critical potential during
Voltage V_FourIs applied to the electrode 5 and the surface of the wafer 6a (etch
Including the side of the ring. ) To form a protective film. These two steps
By sequentially repeating the steps, a high aperture is obtained in the same manner as in the first embodiment.
Machining a material to be etched with a spec ratio with good dimensional accuracy
Can be. The etching time t_ThreeAnd deposition time
t_FourIs the etching time t described in the above embodiment.₁And bank
Product time t_TwoIt may be set in the same manner as in. Hereinafter, according to the second embodiment, the frequency 2
The critical voltage is sandwiched between the output voltages of high-frequency voltages below MHz.
Do not switch and supply gas by changing
In addition, it is necessary to alternately perform the etching process and the deposition process.
The processing time can be reduced in the same way as in the first embodiment.
There is an effect that can be. Further, similarly to the above-described embodiment, the microwave
The processing is performed by plasma and the output voltage control means 24
By controlling the time between etching and deposition, the wafer 6a
Stepwise etching while protecting the etched side surface with a protective film
The fine pattern and the pattern dimension width
If the film to be etched is deeper or higher than
Can be processed well. Further, the generation of plasma is performed in the same manner as in the first embodiment.
Etching in a state where the raw state does not change and the emission intensity is stable
The end point of etching can be easily determined.
I can. Further, the voltage for accelerating the ions is
It is given in the negative voltage range of high frequency voltage of 2MHz or less.
Then, it is accelerated in the negative voltage region and pulled to the surface of the wafer 6a.
The positive ions attracted and charged on the wafer 6a
In the voltage region, the electrons drawn into the surface of the wafer 6a
Therefore, the neutralization can be performed, and the neutralization formed on the wafer 6a can be prevented.
It is possible to prevent dielectric breakdown and the like of the rim material. Accordingly
And Sio_TwoAnd Si_ThreeN_FourSample with insulation like
It is suitable for etching. In this case,
A kind of capacitor between electrode 5-wafer 6 a-plasma
Therefore, the frequency of the high-frequency voltage decreases.
In this case, the electric charge is excessively accumulated on the wafer 6a, and
The etching speed is suppressed and the etching rate is significantly reduced.
That is, a so-called charge-up phenomenon occurs. This char
The limit frequency that prevents the zip-up phenomenon depends on the type of insulating film.
And the thickness of the semiconductor device.
The values for use are detailed in Japanese Patent Publication No. 56-37311.
As described, it is about 100 KHz. Next, a third embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In FIG. 9, the same reference numerals as those in FIG.
One member is shown. The difference between this figure and Fig. 7 is that
In this case, a high frequency of 385 KHz
In that a power supply 23 and an AC waveform generator 26 are used.
You. High frequency power supply 23 is connected to electrode 5 via synthesizer 25
I have. An AC waveform generator 26 is also connected to the synthesizer 25.
Continued. Output waveform control means is provided in the AC waveform generator 26.
27 is connected. The synthesizer 25 outputs a signal from the high frequency power supply 23.
The high-frequency voltage waveform is shown in FIG.
It changes along the waveform 28 output from the generator 26.
The output waveform control means 27 outputs from the AC waveform generator 26.
The cycle and amplitude of the waveform 28 are adjusted. The plasma processing treatment configured as described above,
In this case, an etching apparatus is used for the second embodiment.
If the etching process is performed under the same conditions, the second
The etching process and the deposition process are alternately performed in the same manner as in the embodiment.
It is possible to perform etching step by step while repeating
it can. That is, as shown in FIG.
Rank V₀'For a negative voltage waveform greater than'_FiveBetween
The etching action predominates and the critical potential V₀’Smaller
Time t for negative voltage waveform₆Sedimentation dominates during
Occurs. The time t at which etching takes place_Fiveand
Time t at which deposition occurs₆Output waveform control when adjusting
The wave output from the AC waveform generator 26 by the control means 27
This can be easily achieved by changing the period of the shape 28. Also,
If you want to increase the etching rate during the
Output from the AC waveform generator 26 by the force waveform control means 27
This can be easily performed by changing the amplitude of the waveform 28 to be input.
However, the etching rate, etching time and
If the deposition time is to be adjusted, the output waveform control means 27
It is necessary to adjust the amplitude and cycle of
It is necessary. As described above, according to the third embodiment, the second
The same effect as that of the embodiment can be obtained. In the case of the third embodiment, the etching
The switching between and deposition gradually progresses. Next, a fourth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In FIG. 11, those having the same reference numerals as those in FIG.
The same members are shown. This drawing is different from FIG.
b is grounded and between the wafer 6 and the discharge space 7
Is provided with a grid electrode 29. Grid electricity
The DC power supply 15 is connected to the pole 29.
Is connected to the output voltage control device 16, and the output voltage control device
An output waveform controller 17 is connected to 16. In this case, the ions are accelerated in the direction of the wafer 6.
The means for applying is to apply a negative DC voltage to the grid electrode 29.
DC power supply 15 to be used. Negative output from DC power supply 15
DC voltage, that is, the acceleration voltage
The means for changing the output voltage is controlled by the output voltage controller 16 and the output waveform controller.
And a control device 17.
Similarly, as shown in FIG.₁Voltage V during₁Control
Control, time t_TwoVoltage V during_TwoTo control. The plasma processing apparatus configured as described above,
In this case, the same as in the first embodiment is performed by using an etching apparatus.
A plasma is generated in the discharge space 7 under the conditions of
15, a negative DC voltage is applied to the grid electrode 29.
You. As a result, ions in the plasma are
The ions accelerated to the side 9 and passed through the grid electrode 29
Reach the wafer 6 and etch the material to be etched on the wafer 6
To run. At this time, the output voltage controller 16 and the output wave
With the shape control device 17, the accelerating voltage larger than the critical potential
Pressure V₁From the DC power supply 15 for time t₁Output for seconds. this
Gives the time t₁For seconds, the etching action predominates,
The wafer 6 is etched. Next, below the critical potential
Acceleration voltage V_TwoFrom the DC power supply 15 for time t_TwoOutput for seconds
You. As a result, the time t_TwoSedimentation is dominant for seconds
And protects the surface of the wafer 6 (including the etched side surface).
A film is formed. By repeating these steps sequentially
The material to be etched on the wafer 6 is
It can be etched stepwise. As described above, according to the fourth embodiment, the grid
An acceleration voltage is applied to the electrode 29, and the acceleration voltage is reduced to a critical potential.
The gas can be switched and supplied by changing
The etching process and the deposition process alternately.
The processing time can be reduced in the same manner as in the first embodiment.
There is an effect that it can be shortened. Further, similarly to the above-described embodiment, the microwave
The output voltage control device 16 and the output
Etching process and deposition by force waveform controller 17
By controlling the time from the process, the etching side of the wafer 6
Is etched step by step while protecting with a protective film,
Fine pattern and deeper than pattern width
Can process tall workpieces with high dimensional accuracy.
Can be. Further, the generation of plasma is performed in the same manner as in the first embodiment.
Etching in a state where the raw state does not change and the emission intensity is stable
The etching end point
Easy to do. In the fourth embodiment, the grid electrode 2
Since a DC voltage is applied to the sample No. 9, the sample is conductive
The grid electrode 29 must be
Power supply connection as in the first, second or third embodiment
In this case, an insulating sample can be processed. Next, a fifth embodiment of the present invention will be described with reference to FIG.
A more detailed description will be given. In FIG. 13, the same reference numerals as those in FIG. 1 denote the same parts.
Shows the material. The difference between this figure and Fig. 1 is that
The upper electrode 34 and the lower electrode 33 are placed in the empty processing container 30.
Is a parallel plate type RIE device with
The parallel plate type electrodes 33 and 34 are used as steps,
High-frequency voltage (in this case, frequency 13.56 MHz)
The point is that the high frequency power supply 13a to be applied is connected. The gas introduction section 3 is provided on the side of the vacuum processing vessel 30.
1 and a gas (not shown) as in the first embodiment.
Sources are connected. The lower part of the vacuum processing vessel 30 is shown in the drawing.
There is an exhaust unit 32 connected to a vacuum exhaust device.
You. The wafer 6 is placed on the upper surface in the lower part in the vacuum processing container 30.
A lower electrode 33 is provided in the vacuum processing vessel 30.
Above the upper electrode 3 disposed opposite to the lower electrode 33
4 are provided. The upper electrode 34 is grounded. Lower part
The pole 33 is attached to the vacuum processing vessel 30 via an insulating material.
The lower electrode 33 has the same shape as that of the first embodiment.
A high-frequency power supply 13a connected via the
DC power supply 15 connected via low-pass filter 14
Are connected. The plasma processing apparatus configured as described above,
In this case, the same as in the first embodiment is performed by using an etching apparatus.
The lower electrode 33 and the upper electrode 34 via the gas introduction part 31
Supply etching gas to discharge space 35 formed between
I do. At the same time, a vacuum is exhausted by a vacuum exhaust device (not shown).
The inside of the processing container 30 is evacuated to a predetermined pressure. This state
At the lower electrode 33 by the high frequency power supply 13a.
A high frequency voltage of 3.56 MHz is applied. This allows
Glow discharge occurs in the discharge space 35, and the etching gas
Is turned into plasma. In this state, the plug has already been set in the same manner as in the first embodiment.
DC bias voltage for accelerating ions in the plasma toward the wafer 6
Pressure is generated at the lower electrode 33. This DC bias voltage
In the same manner as in the first embodiment, the critical voltage is
Change the position between them. Thereby, the one embodiment and
Similarly, alternately repeat the etching process and the deposition process
Then, the material to be etched of the wafer 6 is gradually etched.
Wear. As described above, according to the fifth embodiment, the DC power supply
15 changes the DC bias voltage across the critical potential.
By switching the gas supply without switching
Alternate etching and deposition steps
It is possible to shorten the processing time as in the above-described embodiment.
be able to. Further, the electrode 33 is connected using the high-frequency power source 13a.
Generate stable plasma in discharge space 35 between
DC power supply 15
Even if the pressure is changed, the plasma generation state can change
No end point determination for etching as in the previous embodiment
Can be easily performed. In the same manner as in the first embodiment, a high aspect ratio
Can be processed with high dimensional accuracy for the material to be etched.
It can be processed regardless of conductive material or insulating material. Next, a sixth embodiment of the present invention is shown in FIG.
A more detailed description will be given. In FIG. 14, FIG. 7 and FIG.
The same reference numerals indicate the same members. This figure is different from Fig.13
Is a means for generating plasma with a frequency of 2 MHz or less.
Use the lower (385 kHz in this case) high frequency power supply 23a
Is the same as the means to accelerate ions
Using a high frequency power supply 23a having a frequency of 2 MHz or less.
It is a point that is used. The high frequency power supply 23a is the same as in FIG.
To the lower electrode 33 via the matching box 22
Continued. One end of the circuit of the matching box 22 is connected
So that the lower electrode 33 is at DC ground potential.
I'm trying. The high-frequency power supply 23a has output voltage control means.
24 are connected. The control contents of the output voltage control means 24
The second embodiment is similar to the second embodiment, and the description is omitted. Also,
C6a has an insulating material as in the second embodiment.
It is. The plasma processing apparatus configured as described above,
In this case, the etching apparatus is used to perform the above-described fifth embodiment.
Similarly, an etching gas is supplied to the discharge space 35, and a vacuum process is performed.
The inside of the processing vessel 30 is evacuated to a predetermined pressure. In this state
385 is applied to the lower electrode 33 by the high frequency power source 23a.
A high-frequency voltage of kHz is applied, and glow is applied to the discharge space 35.
Discharge is generated and the etching gas is turned into plasma.
You. At this time, the output voltage control means 24
Thus, the output from the high-frequency power supply 23a is
The high-frequency voltage is changed across the critical potential. to this
Thus, the etching step and the deposition are performed in the same manner as in the second embodiment.
The process is alternately repeated to etch the wafer 6a.
The material can be etched stepwise. As described above, according to the sixth embodiment, the frequency 2
The high-frequency voltage of MHz or higher is changed with the critical potential
Supply the gas by switching the etching gas
And the etching process and the deposition process are performed alternately
And the processing time can be reduced as in the second embodiment.
can do. Further, in the same manner as in the second embodiment, a high
Can process the material to be etched with a spec ratio with high dimensional accuracy
You. In addition, it is suitable for a sample having an insulating material.
is there. Note that, in this case, the peripheral that is also the plasma generating means is used.
Since the high frequency voltage with a wave number of 2 MHz or less is changed,
The state of plasma generation is different between the etching process and the deposition process.
Different. For this reason, the etching is completed using emission spectroscopy.
When performing point determination, the
It is necessary to make a determination by inputting only the emission intensity. Next, a seventh embodiment of the present invention is shown in FIG.
A more detailed description will be given. In FIG. 15, FIG. 9 and FIG.
The same reference numerals indicate the same members. This figure is different from Fig. 14
Is a frequency of 2 MHz or less, which is a means of accelerating ions.
The height of the high frequency power supply 23a below (in this case, 385 KHz)
Frequency voltage as a means of changing the critical potential
The point is that the flow waveform generator 26 is used. High frequency power supply 2
3a is a lower electrode 3 via a combiner 25 as in FIG.
3 is connected. The synthesizer 25 also has an AC waveform generator
26 is connected. The output waveform is output to the AC waveform generator 26.
Control means 27 is connected. The synthesizer 25, the AC waveform generator 26 and the output
The control contents of the force waveform control means 27 are the same as in the third embodiment.
The description is omitted. The plasma processing apparatus configured as described above,
In this case, the etching apparatus is used to perform the processing according to the sixth embodiment.
Similarly, an etching gas is supplied to the discharge space 35, and a vacuum process is performed.
The inside of the processing vessel 30 is evacuated to a predetermined pressure. In this state
Here, as in the third embodiment, that is, in the tenth embodiment,
Apply high frequency voltage controlled as shown to lower electrode 33
Then, a blow discharge is generated in the discharge space 35, and the etching is performed.
The switching gas is turned into plasma. As a result, the high frequency voltage is higher than the critical potential.
When larger, the etching action is superior to wafer 6a
When the potential is lower than the high-frequency potential,
(Including the switching side), the deposition effect of the protective film predominates
You. The etching process and the deposition process are performed alternately.
And the material to be etched on the wafer 6a is etched stepwise.
Is done. As described above, according to the seventh embodiment, the sixth embodiment
The etching gas is switched and supplied in the same manner as in the embodiment.
The etching process and the deposition process are performed alternately without any
Can reduce processing time.
You. In this case, even in the case of the plasma generating means,
Since a certain high-frequency voltage is constantly changing,
Raw condition is not constant. For this reason, etching conditions
There is a problem that setting is difficult. Next, an eighth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. 17 and FIG. In FIG. 16, the same reference numerals as those in FIG. 13 denote the same parts.
The members are shown. This drawing differs from FIG.
In this case, a high frequency of 13.56 MHz is used.
The output voltage of the frequency power supply 13a can be controlled,
The point that the means for changing the critical potential is also used
It is. The high frequency power supply 13a is connected to the capacitor 36 and the
Connected to the lower electrode 33 via the
It is. The high-frequency power supply 13a includes an output voltage control unit 24.
Connected. The output voltage control means 24 is a high-frequency power supply 13a
The waveform of the high-frequency voltage output from the
And time t₇Is between the DC component bias voltage V₉Will be
The total amplitude of the high frequency voltage is V₇And the next time t₈of
The bias voltage of the DC component is V_TenHigh frequency so that
V is the total amplitude of the voltage₈To control. The plasma processing apparatus configured as described above,
In this case, the etching apparatus is used to perform the above-described fifth embodiment.
Similarly, an etching gas is supplied to the discharge space 35, and a vacuum process is performed.
The inside of the processing vessel 30 is evacuated to a predetermined pressure. In this state
In this case, the high frequency power supply 13 a
Wave voltage is applied. As a result, the air in the discharge space 35 is removed.
The etching gas is turned into plasma. At this time, as shown in FIG.
Time t by control means 24₇High frequency power supply 13a
V is the total amplitude of the high-frequency voltage output from₇To control. This
As a result, a direct current larger than the critical potential is applied to the sample electrode 33.
Component bias voltage is generated, and the material to be etched of the wafer 6 is
Is etched. Next time t₈High frequency power supply 1
V is the total amplitude of the high frequency voltage output from₈Control
You. As a result, the sample electrode 33 has a potential lower than the critical potential.
A bias voltage of a DC component is generated, and the surface (edge)
A protective film is deposited on the surface of the protective film (including the side of the chuck). This etch
By alternately performing the wetting process and the deposition process,
The material to be etched of C is etched stepwise. As described above, according to the eighth embodiment, the fifth embodiment
The etching gas is switched and supplied in the same manner as in the embodiment.
The etching process and the deposition process are performed alternately without any
Can reduce processing time.
You. Also, the output voltage control means 24
By controlling the output voltage of the wave power supply 13a,
DC bias voltage alternates across critical voltage
The etching process and the deposition process alternately
And the pattern size is the same as in the fifth embodiment.
A film to be etched whose depth or height is higher than the
Processing can be performed with high dimensional accuracy. Further, even if the high-frequency voltage is controlled,
Has a positive voltage range, so that the fifth embodiment
As in the example, no charge is accumulated on the wafer 6 and the etching speed
Edge without degradation or destruction or destruction of the device gate.
Ching can be performed. In this case, the same operation as in the sixth embodiment is performed.
Generation of plasma during the etching process and the deposition process
Since the state changes, the etching end point is determined using emission spectroscopy.
When making a judgment, make sure that the etching
It is necessary to determine only by inputting the light emission intensity. Next, a ninth embodiment of the present invention will be described with reference to FIG.
A more detailed description will be given. In FIG. 18, FIG. 11 and FIG.
The same reference numerals denote the same members. FIG. 18 differs from FIG.
As a means for accelerating ions,
A grid electrode is provided between the wafer 6 and the discharge space 35 as described above.
The point is. The grid electrode 29 has a DC power supply 15
Is connected to the DC power supply 15 and the output voltage control device 1
6 and the output voltage control device 16 has an output waveform control device.
The device 17 is connected. A DC power supply 15, an output voltage control device 16 and
The control contents of the output waveform control device 17 are the same as those of the fourth embodiment.
This is the same as the example, and the description is omitted. The plasma processing apparatus configured as described above,
In this case, the etching apparatus is used to perform the above-described fifth embodiment.
Similarly, an etching gas is supplied to the discharge space 35, and a vacuum process is performed.
The inside of the processing vessel 30 is evacuated to a predetermined pressure. In this state
In this case, the high frequency power supply 13 a
Wave voltage is applied. As a result, the air blows into the discharge space 35.
A discharge is generated and the etching gas is turned into plasma. In this state, as in the fourth embodiment, the direct
A negative DC voltage is applied to the grid electrode 29 by the
Apply. As a result, ions in the plasma
Ions accelerated to the electrode side and passed through the grid electrode 29
Reaches the wafer 6 and etches the material to be etched of the wafer 6.
Ching. At this time, output is performed in the same manner as in the fourth embodiment.
By the voltage control device 16 and the output waveform control device 17,
The acceleration voltage applied to the grid electrode 29 is set to a critical potential.
And change it. As a result, the acceleration voltage becomes higher than the critical potential.
When larger, the etching action is superior to wafer 6
Occurs. When the acceleration voltage is lower than the critical potential,
A protective film is formed on the surface (including the etched side surface) of C6.
Predominant sedimentation occurs. This etching process and
By alternately performing the stacking process, the wafer 6 is etched.
The ting material is etched stepwise. As described above, according to the ninth embodiment, the grid
Acceleration voltage applied to electrode 29 changes across critical potential
The gas without switching and supplying gas.
It is possible to alternately perform the etching process and the deposition process.
Therefore, the processing time can be reduced in the same manner as in the fifth embodiment.
Can be Further, similarly to the fifth embodiment, the wafer 6
Stepwise etching while protecting the etched side surface with a protective film
Can be deeper than the pattern width.
Can process tall workpieces with high dimensional accuracy.
Can be. Also, as in the case of the fifth embodiment, the plasma
The state of light emission does not change, and
The end point of etching can be easily determined.
I can. Next, a tenth embodiment of the present invention will be described with reference to FIG.
This will be described below. In FIG. 19, the same symbols as in FIG. 13 are the same.
The members are shown. This drawing differs from FIG.
As a production means, a discharge tube 37 is provided outside the vacuum processing vessel 30.
Then, a coil 38 is wound around the outer circumference of the discharge tube 37 to
In that a high frequency power supply 39 is connected to the
is there. The lower electrode 33 has a high frequency as in FIG.
Of DC bias by wave power supply 13a and DC power supply 15
Means, ie, means for accelerating the ions, are provided. this
The plasma generating means and the DC bias applying means
The output can be controlled independently of each other. High lap
The wave power supply 39 has, for example, a frequency of 80 kHz to 13.56.
It outputs high-frequency power of MHz. DC via
The contents of control by the means for assigning resources are the same as in the fifth embodiment.
Therefore, the description is omitted. The plasma treatment apparatus configured as described above,
In this case, a gas source (not shown) is
Into the discharge tube 37 through the gas inlet 31a
Vacuum processing vessel by supplying gas and using an exhaust device not shown
The inside of the chamber 30 and the inside of the discharge tube 37 are evacuated to a predetermined pressure.
In this state, high frequency power is applied to the coil 38 by the high frequency power supply 39.
Wave voltage is applied. Thereby, the etching inside the discharge tube 37 is performed.
Gas is turned into plasma, and the plasma is
30 is introduced into the space 35a. At this time, via the matching box 12
To the lower electrode 33 by the high frequency power supply 13a.
Is applied. Thereby, the high voltage applied to the lower electrode 33 is
The frequency voltage is DC floating as in the fifth embodiment.
And has a DC bias voltage. With this high frequency voltage
Then, a DC voltage is applied to the lower electrode 33 by the DC power supply 15.
Well, it controls the DC bias voltage. The DC bias voltage is applied to the output voltage controller 16.
And the output waveform control device 17 according to the fifth embodiment.
Control as follows. This allows the etching process and deposition
The process is performed alternately, and the material to be etched of the wafer 6 is
It is etched stepwise. As described above, according to the tenth embodiment, the tenth embodiment
The same effect as that of the fifth embodiment can be obtained. According to the tenth embodiment, the high frequency
Without increasing the high frequency voltage of the power supply 13a, the discharge tube 37
Since high-density plasma can be generated in the
Compared to the embodiment, it is possible to perform high-speed etching with less damage.
Can be. As described above, based on the first to tenth embodiments,
The present invention has been described with reference to the drawings.
It is not limited to the example, and plasma generation means and acceleration
Various combinations of voltage applying means and accelerating voltage applying means
It goes without saying that they can be combined. In this embodiment, polysilicon etching is performed.
SF without critical potential₆And the limit
C with position_TwoCl_ThreeF_ThreeAn example using a gas mixture with
However, if the gas has a property with a critical potential,
Needless to say, the combination is also acceptable. For example, critical
SF without potential₆And C having a critical potential_TwoCl_ThreeF_Three
(Product name: Freon 114), CCl_FourOr C_FourF₈etc
And SF₆NF instead of_ThreePair using
The same can be done with the combination. Also, the mixed components of the etching gas are reduced to two.
Without limitation, at least one component has a critical potential
May be composed of three or more components.
No. A combination of gases in which all components have a critical potential,
Alternatively, a single gas may be used. In this embodiment, the polysilicon is etched.
Example of etching, but also applicable to etching of Al wiring film
It is possible. In this case, the etching gas is critical
Chlorine gas as a pure potentialless etchant
(Cl_Two), Cl component and film as etchant
Critical potential is composed of C component acting as a part of the forming species.
Having CCl_FourMixed gas with the material to be etched
BCl for high-speed etching of surface oxide film_ThreeAdd
The mixed gas obtained may be used. In this case, AlCl_ThreeWhat
Volatile reaction products are generated,
Etching is performed, and C polymer or CxCly reacts.
Reaction products are generated as deposits to form a protective film.
CCl having a critical potential_FourInstead of CF_Four, C_Two
F₆, C_FourF₈Or SiCl_FourEtc. may be used. FIG. 2 shows specific numerical values.
None, but the etch or deposition rate, and
The field potential depends on the type of etching gas, gas pressure and plasma.
Is relatively determined by the output of the
You. In this embodiment, the processing during the etching process is performed.
Although the application pattern of the fast voltage was the same,
Acceleration within the range above the critical potential at the end of ringing
By performing control to reduce the voltage, the etch
Wing damage can be further reduced. In this embodiment, the acceleration voltage is set to the critical potential.
The time to change between is set at a preset time
Although switching is performed automatically, the edge at each stage is changed.
Detecting the ching and deposition conditions and detecting the respective
Switch automatically when the value reaches the specified value
You can do it. In the case of processing with few switching times,
In such a case, the switching may be performed manually. Note that this
When setting the acceleration voltage, the acceleration voltage is detected and
Display the detected value and check the value to be adjusted
Just set it to a value. Further, in this embodiment, etching is performed.
As described above, the etching and deposition processes
In other words, the ratio of the time to the film forming process is reversed, and
The present invention is also applicable to a case where a film is formed. in this case
Is achieved by alternately performing film formation and etching.
A smooth film can be formed. [0130] According to the present invention,Plasma under low pressure
Because it occurs inAccelerate the ions in the plasma with a small acceleration
Pull into sample by pressureLess damageAs well as
When the accelerating voltage is higher than the critical potential, the sample is etched.
Dominant effect and acceleration voltage is lower than critical potential
When the sedimentation action predominates in the sample,These edges
Alternating and film formation, forming by film formation
The protective film on the sidewall of the patterned pattern is removed during etching.
So that the pattern width does not decreaseFine
Material to be etched with a pattern and a large aspect ratio
There is an effect that it can be processed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing a plasma processing apparatus according to one embodiment of the present invention. FIG. 2 is a diagram showing a relationship between a bias voltage and an etching rate or a deposition rate in a processing gas. FIG. 3 is an application pattern diagram of an acceleration voltage by the apparatus of FIG. 1; FIG. 4 is a diagram showing an etching state when a bias voltage is not changed. FIG. 5 is a diagram showing an etching state according to the present invention. FIG. 6 is a diagram showing an etching state according to the present invention. FIG. 7 is a configuration diagram illustrating a plasma processing apparatus according to a second embodiment of the present invention. FIG. 8 is an application pattern diagram of an acceleration voltage by the apparatus of FIG. 7; FIG. 9 is a configuration diagram illustrating a plasma processing apparatus according to a third embodiment of the present invention. 10 is an application pattern diagram of an acceleration voltage by the apparatus of FIG. 9; FIG. 11 is a configuration diagram illustrating a plasma processing apparatus according to a fourth embodiment of the present invention. FIG. 12 is an application pattern diagram of an acceleration voltage by the apparatus of FIG. 11; FIG. 13 is a configuration diagram illustrating a plasma processing apparatus according to a fifth embodiment of the present invention. FIG. 14 is a configuration diagram illustrating a plasma processing apparatus according to a sixth embodiment of the present invention. FIG. 15 is a configuration diagram illustrating a plasma processing apparatus according to a seventh embodiment of the present invention. FIG. 16 is a configuration diagram showing a plasma processing apparatus according to an eighth embodiment of the present invention. 17 is an application pattern diagram of an acceleration voltage by the apparatus of FIG. 16; FIG. 18 is a configuration diagram illustrating a plasma processing apparatus according to a ninth embodiment of the present invention. FIG. 19 is a configuration diagram showing a plasma processing apparatus according to a tenth embodiment of the present invention. [Description of Signs] 1 ... discharge tube, 5 ... electrode, 6,6a ... wafer, 8 ... magnetron, 10 ... electromagnetic coil, 12 ... matching box, 13,13a ... high frequency power supply, 15 ... DC power supply, 16
... Output voltage controller, 17 ... Output waveform controller, 22 ...
Matching box, 23, 23a ... high frequency power supply, 24
... output voltage control means, 25 ... synthesizer, 26 ... AC waveform generator, 27 ... output waveform control means, 29 ... grid electrode,
Reference numeral 30 denotes a vacuum processing container, 33 and 34 an electrode, 36 a capacitor, 37 a discharge tube, 38 a coil, and 39 a high frequency power supply.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Yoshimichi Hirobe               1 Horiyamashita, Hadano-shi, Kanagawa                 Hitachi, Ltd., Kanagawa Plant (72) Inventor Yutaka Kakehi               502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref.                 Hitachi, Ltd.                (56) References JP-A-57-164986 (JP, A)                 JP-A-62-154734 (JP, A)

Claims (1)

(57) [Claims] A mixed gas having a component that reacts with the material to be etched and a component that forms a deposited film and has a critical potential is used as an etching gas. Forming a plasma, and changing an acceleration voltage for accelerating ions in the plasma toward the material to be etched with the critical potential interposed therebetween, and alternately repeating etching and film formation on the material to be etched. And a protective film for a pattern side wall surface formed by the film formation.
A plasma processing method characterized by performing etching with a fine pattern and a high aspect ratio while removing at the time of the next etching .