JP3396015B2 - Ion energy measuring method and apparatus, and plasma processing apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ion energy measuring method and apparatus.

[0002]

2. Description of the Related Art In a plasma processing apparatus used in a semiconductor manufacturing process for manufacturing a semiconductor wafer, LCD substrate, etc., a reactive gas plasma is excited or introduced into an airtight processing chamber so that a mounting table in the processing chamber ( Predetermined plasma processing is performed on the object to be processed placed on the susceptor. Then, high-frequency power for bias is applied to the susceptor on which the object to be processed is placed, and the plasma in the processing chamber is effectively drawn into the surface to be processed of the object to be processed, so that desired plasma processing can be performed. It is configured to be able to do.

By the way, in order to perform a desired plasma treatment on an object to be processed, ions generated in the plasma space are accelerated in the ion sheath space and the energy distribution when reaching the object to be processed is accurately measured, Based on the result, it is necessary to adjust various parameters of the plasma processing apparatus, for example, high frequency power and bias high frequency power.

Therefore, in the past, for example, Japanese Patent Laid-Open No. 6-4
A blocking potential type energy analyzer as proposed from the disclosure of No. 4931 is used. In such a blocking potential type energy analyzer, the ion energy incident on the object to be processed is not directly measured, but a measuring device composed of four grids and a Faraday cup is provided in the vicinity of the plasma generated in the processing chamber. , Indirectly.

That is, of the four grids provided from the plasma side to the Faraday cup side, the DC power applied to the third grid from the plasma side is changed to pass through the fourth grid. The current value of the ions entering the Faraday cup is measured with an ammeter, and the rate of change is determined from the change in the ion current value to determine the ion energy.

[0006]

However, in the case of plasma processing using high frequency power for bias, in the conventional ion energy analyzer, the object to be processed on the susceptor is caused by the AC component of the high frequency power for bias. It was difficult to accurately measure the energy distribution of ions incident on. Therefore, a large difference may occur between the actual ion energy distribution on the object to be processed and the ion energy distribution on the object to be processed determined by the analyzer, which makes it impossible to perform highly accurate plasma processing. It was

Further, since the above-mentioned conventional ion energy distribution measuring device must be provided in the vicinity of plasma, in order to measure a value close to the actual ion energy,
The analyzer had to be exposed to the plasma, especially in a space having a high plasma density, which was a factor of shortening the life of the analyzer.

On the other hand, if the distance from the plasma is increased in order to improve the life of the ion energy distribution measuring device, there is a problem that a large difference occurs between the actual ion energy distribution and the measured ion energy distribution. Was becoming.

The present invention has been made in view of the above problems of the conventional ion energy measuring method and apparatus, and the ion energy distribution of the ions incident on the object to be processed is directly measured to obtain an accurate measurement. It is an object of the present invention to provide a new and improved ion energy measuring method and apparatus capable of obtaining an ion energy distribution on an object to be processed.

[0010]

Means for Solving the Problems] To solve the above problems, according to claim 1, at least comprising measuring system collector means disposed at a position at a predetermined distance with respect to the dummy wafer, RF power field Dummy affected by
An ion energy measurement method for measuring the ion energy on the wafer: first measuring the ion energy in a plurality of phases of the RF power of ions having passed through the dummy wafer in time-resolved manner by said collector means
And the ion energies at the plurality of phases
A second step of obtaining by calculation the ion energy on the dummy wafer on the basis of the measured values of over, the second
The ion energy obtained in step by combining the da
And a third step of obtaining an ion energy distribution on the wafer .

According to a second aspect of the present invention, the measuring system comprises:
Further comprising a sequential plurality of grid means disposed between the dummy wafer and said collector means, said first
Step, said changing the DC voltage applied to the grid means, by detecting a change in current of the ions passing through the grid means, ions in the plurality of phases of the RF power applied to the dummy wafer It is characterized by measuring energy.

Therefore, an object to be measured (for example, a dummy wafer)
Even if the ion energy of the ions incident on ( c) changes temporally due to the AC component of the RF power applied to the measurement object, it becomes possible to measure by the first step of time-resolved measurement. Obtaining the ion energy on the measurement object at each time from the ion energy at each time measured in one step, and synthesizing them to obtain the ion energy on the measurement object to which RF power is applied. You can

According to a third aspect of the present invention, the DC voltage applied to the grid means is given a reference potential by a self-bias voltage generated in the dummy wafer by the application of the RF power.
The ion energy can be accurately measured when the self-bias voltage value is large or small.

Further, according to claim 4, the first step further comprises a step of selecting a peak value from the measured ion energy and obtaining a peak distribution based on the peak value. A desired ion energy can be measured by removing unnecessary ones from the measured ion energy.

Still further, according to claim 5, the second
Step, from the unique value of at least the peak value selected in the first step and the measuring system, the
Since the ion energy on the dummy wafer is measured, the desired ion energy can be measured by changing only the DC voltage applied to the grid means in the measurement system.

Further, according to claim 6, measured with at least a plurality of the grid means successively disposed between the collector means and the dummy wafers and the collector means which is disposed at a position at a predetermined distance with respect to the dummy wafer Depending on the system
An ion energy measuring method for measuring ion energy on the dummy wafer affected by an electric field of RF power: changing a DC voltage applied to the grid means; current of the ions passing through the grid means The change in the
There are multiple phases of the RF power in the collector means.
It is characterized and characterized in that it consists of; takes the steps of measuring the ion energy; and determining an ion energy distribution on the dummy wafer on the basis of the specific value of the measurement system and its measured the ion energy.

Therefore, the ion energy of the ions incident on the object to be measured is R applied to the object to be measured.
Even if it changes with time due to the AC component of the F power, the DC voltage applied to the grid means is changed according to the change, and only the DC voltage is adjusted without adjusting other measurement systems. The accurate ion energy of can be measured.

According to a seventh aspect of the present invention, a dummy window mounted on a mounting table to which RF power is applied in the processing chamber.
An ion energy measuring device for measuring the ion <br/> emission energy at the RF power of a plurality of phases to be irradiated to the E c: inside the mounting table to a predetermined distance with respect to at least the dummy wafer position It is characterized arranged and collector means are, successively by providing a plurality of grid means disposed between the dummy wafer and collector means.

Therefore, an ion energy measuring device can be provided in the vicinity of the object to be measured, and only the ion energy of the ions incident on the object to be measured can be measured, so that the ions on the actual object to be measured can be measured. It is possible to measure the ion energy on the measurement object that is substantially the same as the energy. According to Claims 8 to 12, the measurement system including at least collector means
Ions affected by the electric field of high-frequency power reach the non-processed body.
Ion energy measuring ion energy distribution as it reaches
In the method of measuring ruggedness:
Measurement of ion energy in multiple phases of frequency power
And the steps measured before at the plurality of phases
Ion energy distribution based on ion energy
And a step of obtaining.
The step of obtaining the ion energy distribution includes the plurality of steps.
Calculate the ion energy measured in the phase of
And a step in the calculated plurality of phases
And a step of synthesizing the ion energy.
You can Further, the measurement system is a mounting table in the processing chamber.
Can be buried in. Further, the plurality of positions
Measuring the ion energy in the phase
Indicates that the dummy wafer which has passed through the dummy wafer placed on the mounting table described above.
It must be a step to measure ON ion energy
You can Furthermore, the measurement system includes a collector and
A grid, the ion energy in the plurality of phases
The step of measuring the energy is applied to the grid.
Of the ions passing through the grid by changing the DC voltage
Can have the step of detecting changes in the throughput
It According to claim 13, the ion energy is
The measurement method is used to measure the ion energy content in the processing chamber.
The cloth is controlled, and the plasma processing is performed on the object to be processed in the processing chamber.
It is characterized by doing.

[0020]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment in which the ion energy measuring method and apparatus according to the present invention is applied to a parallel plate type etching apparatus will be described in detail. In the following description, components having substantially the same function and configuration will be assigned the same reference numeral, and redundant description will be omitted.

First, the etching apparatus 100 shown in FIG.
The overall configuration of will be described. The processing chamber 102 of the etching apparatus 100 is formed in an airtight and closable substantially cylindrical processing container 104 made of a conductive material such as aluminum whose surface is anodized.

At the bottom of the processing chamber 102, a susceptor 106 made of a substantially cylindrical conductive material, such as aluminum whose surface is anodized, on which the object W to be measured can be placed is provided. The surface of the susceptor 106 is covered with a polymer film 110 made of an insulating material such as polyimide, and the measurement target W is placed on the susceptor 106.
Is placed. The measurement target W is, for example, a dummy wafer W corresponding to a 12-inch semiconductor wafer, and the surface to be measured has a hole for ion permeation as described later with reference to FIG. Further, the susceptor 106
2 and 4, the ion energy detector 150 used in accordance with the present invention is described below.
Is embedded. Since the cross-sectional view of the etching apparatus 100 shown in FIG. 1 is schematically illustrated, the DC power supplies 158, 160, 164 and the ammeter 166 in FIG.
Etc. are omitted.

Further, the susceptor 106 on which the dummy wafer W is placed is passed through the matching unit 114 and the high frequency power source 1
16 are connected. From the high frequency power supply 116, a predetermined high frequency power for plasma generation and bias (hereinafter referred to as "RF power"), for example, 13.56 MHz.
Of the high frequency power of the susceptor 106 via the matching device 114.
Is applied to plasma, plasma is generated between the plasma and an upper electrode 124, which will be described later, and ions in the plasma can be effectively attracted.

Below the side wall of the processing chamber 102, the exhaust pipe 12 is provided.
0 is connected to the exhaust pipe 120. Further, the exhaust pipe 120 is provided with a vacuuming means (P) 12 including a turbo molecular pump, for example.
2 is connected. Therefore, the inside of the processing chamber 102 can be evacuated through the exhaust pipe 120 by the operation of the evacuation means 122 to a predetermined decompressed atmosphere, for example, an arbitrary decompression degree of 1 to 100 mTorr.

On the other hand, the susceptor 106 above the processing chamber 102.
An upper electrode 124 made of a conductive material having a diameter substantially the same as that of the susceptor 106, for example, made of aluminum whose surface is anodized, is provided at a position opposed to. The upper electrode 124 is grounded and the gas supply pipe 12
6 is connected, and this gas supply pipe 126 is connected to a gas supply source 132 via a valve 128 and a mass flow controller MFC 130 for adjusting the flow rate of gas.

Further, the inside of the upper electrode 124 has a hollow structure having a hollow portion 124a, and a large number of ejection openings 124c are formed on the surface 124b facing the wafer W. Therefore, a predetermined process gas, for example, C ₄ F ₈ gas is supplied from the gas supply source 132 to the mass flow controller MFC.
130, the valve 128 and the gas supply pipe 126,
After being introduced into the hollow portion 124a in the upper electrode 124, it is uniformly introduced into the processing chamber 102 through the ejection port 124c.

Next, the configuration of the ion energy measuring apparatus according to this embodiment will be described with reference to FIGS.

As shown in FIG. 2, on the mounting surface of the susceptor 106, ion energy detection is performed in a substantially cross-shape that extends radially from the substantial center toward the peripheral portion, for example, a height of 1 cm and a diameter of 1 cm. For example, nine vessels 150 are provided. The arrangement is such that one is provided substantially at the center of the mounting surface of the susceptor 106, and further, from the ion energy detector 150 toward the outer peripheral direction of the susceptor 106 in substantially the same shape, for example, at equal intervals of 6 cm. , Two are provided for each.

As shown in FIG. 3, the dummy wafer W used in the ion energy measurement according to the present embodiment is made of a conductive material, for example, silicon whose surface is covered with a silicon oxide film. When it is placed on the susceptor 106 in a substantially disc shape of inch, a large number of penetrating holes are formed at a position corresponding to the ion energy detector 150, which is substantially the same as the diameter of the ion energy detector 150, for example, a circle having a diameter of 1 cm. A hole Wa is provided.

The through-hole Wa is provided with a hole that allows ions entering the dummy wafer W to be efficiently transmitted to the ion energy detector 150 on the susceptor 106 and does not affect the plasma state. It is preferable. When the dummy wafer W is placed on the susceptor 106, the ions passing through the dummy wafer W enter the ion energy detector 150.

As shown in FIG. 4, the ion energy detector 150 is embedded in the susceptor 106, and its upper portion is close to the dummy wafer W. Further, the ion energy detector 150 has a substantially tubular shape, and inside the ion energy detector 150, from the dummy wafer W toward the susceptor 106,
For example, three grids 152 (152a, 152b, 1
52c) and a sensor 154, eg a Faraday cup, which acts as a collector.

The grid 152 (152a, 152a)
b, 152c) are referred to as the top grid 152a, the second grid 152b, and the last grid 152c from the dummy wafer W side.

First, the grid 152 (152a, 152a)
b, 152c), the top grid 152a, the second grid 152b, and the last grid 152c are electrode plates 156a, 156b, and 156a, which are made of a substantially annular conductive material provided on the inner wall of the ion energy detector 150, for example, tungsten. Each of them is attached to 156c.

The interval between the grids 152 is preferably a fraction of the average free path of plasma ions or less, and when the pressure in the processing chamber 102 is, for example, about 1 mTorr, the average free path is several cm. Therefore, it is preferably 1 mm to 10 mm, for example.

Further, each grid 152 has, for example, a diameter of 2
The tungsten wire of 0 μm forms a mesh shape with an interval of 254 μm, for example.

The electrode grid 156a to which the top grid 152a is attached and the last grid 152
Direct current power supplies 158 and 160 are connected to the electrode plate 156c to which c is attached, and a negative direct current voltage, for example, a direct current voltage of -60V is applied to each of them.

Further, the variable voltage DC power supply 1 is attached to the electrode plate 156b to which the second grid 152b is attached.
62 is connected, and a positive variable DC voltage is applied thereto.

Here, each grid 152 (152a, 1a)
52b, 152c) will be described. First, the top grid 152a is provided to prevent electrons in the plasma generated in the processing chamber 102 from entering the ion energy measuring instrument 150.

Therefore, it is necessary to apply a negative potential relatively larger than the energy of the electrons to the top grid 152a. For example, for plasma in a normal dry etching apparatus, it is preferable to apply a negative potential larger than 60 V to the top grid 152a.

Next, in the last grid 152c, the ions that have passed through the second grid 152b are detected by the sensor 1
It is provided to block secondary electrons generated when the ions collide with 54.

Therefore, it is necessary to apply a negative potential relatively larger than the energy of the secondary electrons to the last grid 152c. In the ion energy measuring instrument 150 according to the present embodiment, it is preferable to apply a negative potential of, for example, about 60 V to the last grid 152c.

Further, in the second grid 152b, among the ions having passed through the top grid 152a, only the ions having the energy larger than the positive DC voltage applied to the second grid 152b pass through the second grid 152b. Is configured.

Then, the grid 152 (152a, 15a
2b, 152c) and the current value of the ions incident on the sensor 154 is measured by an ammeter 166 which is connected to the sensor 154 and a DC power source for ion collection via 164.

At this time, by changing the positive DC voltage applied to the second grid 152b, the passing amount of the ions reaching the sensor 154 is changed, and the current value of the ions at the sensor 154 is measured by the ammeter 166. However, the ion energy of the ion at the sensor 154 can be measured from the rate of change.

The ammeter 166 has a grid 152 (152a, 1a, 1a) in addition to the electrical path from the sensor 154.
52b, 152c) are connected to a DC power source 158, 160 for applying a DC voltage and a variable DC power source 162, respectively, as one electric path, and the path is a self-bias voltage of high frequency power from a signal on the dummy wafer W. Is connected to the dummy wafer W via a self-bias voltage extraction circuit 168 for extracting

Next, from the measurement value of the ammeter 166,
The process of obtaining the ion energy distribution on the measurement target will be described.

First, a dummy wafer W to be measured is placed on the susceptor 106, and a predetermined processing gas such as C ₄ is stored in the processing chamber 102 in which a predetermined reduced pressure atmosphere, for example, a reduced pressure atmosphere of 1 mTorr is maintained. When F ₈ gas is introduced and a predetermined high frequency power, for example, 13.56 MHz high frequency power is applied to the susceptor 106, plasma is generated in the processing chamber 102.

Then, the ions in the plasma generated in the processing chamber 102 are attracted to the dummy wafer W by the self-bias voltage generated by the application of the high frequency power.

Of the ions and electrons in this plasma, only the ions reach the sensor 154, as described above. At this time, the DC voltage applied to the second grid 152b is changed to change the passing amount of the ions reaching the sensor 154, and the current of the ions is measured by the ammeter 166.
To measure.

Then, a curve is obtained from the voltage value of the variable DC voltage applied to the second grid 152b and the current value of the ions reaching the sensor 154, and the curve is first differentiated to obtain the ion energy distribution of the ions in the sensor 154. Obtainable.

However, the susceptor 106 has an RF
Since the electric power is applied, the ion energy distribution of the ions in the sensor 154 changes with time due to the influence of the AC component of the RF power.

However, since this time change changes at substantially the same cycle as the cycle of the AC component of the RF power, it is time resolved by a digital oscilloscope, boxcar integrator, or the like (not shown) for each phase. Division, sensor 154
The ion energy distribution of the ions at can be obtained.

Therefore, as shown in FIG.
Time-resolving the ion energy of the ions in 4,
It is assumed that the ion energy distribution of the ions in the sensor 154 at 8 points (P1 to 8 in the figure) is obtained for each phase, for example, for one cycle of the AC component of RF power.

First, the sensor 154 obtained for each phase
As shown in FIG. 6, in the ion energy distribution of the ions in, the respective peaks are usually so-called broad, and many smaller peaks are included in many cases. As shown, the ion energy distribution for each phase is simplified so that only the peak has a large peak.

Next, the peak, which is the ion energy distribution of the ions in the sensor 154 simplified for each phase, obtained as described above, is calculated by the calculating means according to the present embodiment described below. It is converted into ion energy on the dummy wafer W for each phase.

The dummy wafer W and the top grid 1
An RF electric field is generated between 52a by the RF power, so that the ion energy distribution of the ions is affected by the RF electric field. However, from the top grid 152a to the sensor 1
An electrostatic field is present between 54 and is not affected by the RF field. Therefore, the conversion of the ion energy of the ions in the sensor 154 into the ion energy on the dummy wafer W is
It is divided into two with the top grid 152a as a boundary.

First, the dummy wafer W and the top grid 1
The electric field between the dummy wafer W and the top grid 152a is the electric field between the dummy wafer W and the top grid 152a divided by the distance between the dummy wafer W and the top grid 152a.

The potential of the dummy wafer W is set to V _(t) '= V ₀ si
If n (ω (t + t ₀ )) and the potential of the top grid 152a is V ₁ , the potential difference V _(t) between the dummy wafer W and the top grid 152a is V _(t) = V _(t) '- V ₁ = V ₀ sin (ω (t + t ₀ )) − V ₁ . Note that ω represents the frequency of the RF power, and t ₀ represents the time when the ions pass through the dummy wafer W.

This is the dummy wafer W and the top grid 1.
52a divided by the distance l to divide V ₀ / l into E ₀ and V ₁ /
If l is E ₁ , dummy wafer W and top grid 1
The electric field with respect to 52a can be represented by the following formula. E _(t) = E ₀ sin (ω (t + t ₀ )) − E ₁ Note that E ₀ represents the amplitude of the electric field due to RF power, and E ₁ represents the DC component of the electric field between the dummy wafer W and the top grid 152a. Represent

Next, the movement of ions between the top grid 152a and the sensor 154 will be described. Between the top grid 152a and the sensor 154, the grid 152 (152a, 152b, 152c) and the sensor 1 are provided.
Ions are accelerated or decelerated by the electrostatic field between 54 to move.

Therefore, the acceleration a of the ions during that period is
It can be determined from the force exerted by the electric field on the ions. Further, the time taken for ions to pass between the top grid 152a and the second grid 152b, between the second grid 152b and the last grid 152c, and between the last grid 152c and the sensor 154 is t2, t3, and t, respectively.
4 and the grid 152 (152a, 152b, 152
If the speed when passing through c) is the initial speed, for example,

[0062]

[Equation 1]

As a grid 152 (152a, 15a)
2b, 152c) and the distance between the sensor 154. It should be noted that l ₂ represents the distance between the top grid 152a and the second grid 152b, a ₂ represents the acceleration between the top grid 152a and the second grid 152b, and v ₁ represents the ion when passing through the top grid 152a. Represents speed. Therefore, if each time is calculated from Equation (1) and integrated, the ions will be in the top grid 152.
The time to reach from a to the sensor 154 can be calculated.

Next, the change in ion energy due to the potential difference between the top grid 152a and the sensor 154 will be described. Sensor 1 from top grid 152a
Since there is an electrostatic field between 54, the top grid 152
It may be calculated by the potential difference between a and the sensor 154.

First, similarly to the above, the time when the ions pass through the dummy wafer W is t _0, and the ion energy at that time is K ₀ . Further, the ions are passed between the dummy wafer W at a distance of 1 and the top grid 152a at time t ₁
The ion energy after passing through was set to K ₁ .

The electric field between the dummy wafer W and the top grid 152a is _expressed by E _(t) = E ₀ sin (ω (t + t ₀ ))-E ₁ as described above. Also, the acceleration a acting on the ions and the electric field E
Is represented by ma = eE, the acceleration a _(t) is

[0067]

[Equation 2]

It can be represented by Note that m is the mass of the ion and e is the charge of the ion. Then, the energy change dK that the ion receives in this electric field during the time dt is
Since the electric field is the same as the work done to the ions, it can be expressed by dK = f _(t) dl. In the above equation, f _(t) is the force that the ion receives, and dl is the distance that the ion has moved during dt, and is expressed as follows.

[0069]

[Equation 3]

The second-order term of dt is omitted. Further, v _(t) is the velocity of the ion at time t, and is as follows.

[0071]

[Equation 4]

Therefore, dK and dl can be expressed by the following equations.

[0073]

[Equation 5]

Next, the amount of change in energy ΔK during the time t ₁ can be obtained by integrating the equation (2).

[0075]

[Equation 6]

V ₀ represents the potential on the dummy wafer W, K ₀ represents the energy when passing through the dummy wafer W, and K represents the energy at the top grid 152a. In addition, unless otherwise specified in the following formula,
The unit of energy is represented by [eV]. on the other hand,
The distance 1 between the dummy wafer W and the top grid 152a is expressed by the following equation by integrating the equation (3).

[0077]

[Equation 7]

[0078] To organize equation (5), the expression for the K ₀ by transforming the equation (4), erases the K ₀ from equation (5).

[0079]

[Equation 8]

[0080]

[Equation 9]

These equations are the central equations for calculating the ion energy distribution on the dummy wafer W according to the present embodiment.

However, ξ and K in equations (8) and (9)
Since there is an unknown number, it is necessary to derive by the formula explained below. The time Δt required for the ions to reach the sensor 154 from the top grid 152a is t
_It is expressed as the sum of ₂ , t ₃ , and t ₄ . For example, when calculating t ₂ may be solved for t ₂ in the numerical formula 1.

[0083]

[Equation 10]

Here, a ₂ is the top grid 152a
Is the acceleration of ions between the second grid 152b and the second grid 152b. Further, in v ₁ , ions are the top grid 152a.
The speed at which the vehicle passes through, and is treated as the initial speed in this area. Then, also for t ₃ and t ₄ , the respective times can be calculated by performing the same calculation.
Adding t ₂ , t ₃ , and t ₄ calculated by the above equation gives the following.

[0085]

[Equation 11]

Here, Kc is the ion energy at the sensor 154, and ΔV is the potential difference between the top grid 152a and the sensor 154. Further, V ₄ represents the potential at the sensor 154, and φ represents the phase at the sensor 154.

Therefore, by substituting the ξ and K obtained by the equations (10) and (11) into the respective equations (8) and (9) and calculating these equations, The ion energy K ₀ on the dummy wafer W can be obtained.

Since the ion energy K ₀ on the dummy wafer W thus obtained is obtained for each phase, the ion energy distribution on the dummy wafer W can be obtained by combining these.

For example, when the ion energies on the dummy wafer W in a certain phase are as shown in FIG. 8 and the ion energies on the dummy wafer W in other phases are as shown in FIGS. 9 and 10, respectively, The ion energy distribution on the dummy wafer W as shown in FIG. 11 can be obtained by synthesizing, that is, superimposing, the ion energies on the dummy wafer W of each phase.

Here, for the sake of explanation, the ion energy distribution on the dummy wafer W was obtained from the ion energy on the dummy wafer W at the phase of 3 points, but in the present embodiment, the dummy wafer of each phase at 8 points is obtained. The ion energy distribution on the dummy wafer W is obtained from the ion energy on W.

As described above, when RF power is applied to the dummy wafer W via the susceptor 106, the ion energy distribution on the sensor 154 at each phase of the RF power is measured in a time-resolved manner, Ions on the dummy wafer W are calculated by simplifying only the main peaks from the obtained measured values, calculating the ion energy distribution on the dummy wafer W at each phase from these peak values, and combining them. The energy distribution can be obtained.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to such a configuration. Within the scope of the technical idea described in the claims, those skilled in the art can contemplate various modifications and modifications, and the modifications and modifications are also within the technical scope of the present invention. Be understood to belong to.

In the above embodiment, the configuration in which nine ion energy detectors 150 are provided on the susceptor 106 has been described as an example, but the present invention is not limited to such a configuration, and the ion energy detectors are not limited thereto. The number of 150 may be increased or decreased depending on the device configuration to which the present invention is applied and the required accuracy of data.

In the above-described embodiment, the ion energy detector 150 is described as an example in which the ion energy detector 150 is provided in a cross shape on the susceptor 106. However, the present invention is not limited to such a configuration and, for example, is omitted. The configuration may be provided in a spiral shape.

Although the ion energy detector 150 is embedded in the susceptor 106 in the above embodiment, the present invention is not limited to such a configuration, and the ion energy detector is embedded in the mounting table. The present invention can be practiced without doing so.

In the above embodiment, the configuration in which the three grids 152 are provided in the ion energy detector 150 has been described as an example, but the present invention is not limited to such a configuration and the ion energy is measured. If possible, any number of grids may be provided.

In the above embodiment, when the ion energy of the ions in the sensor 150 is time-resolved, R
The description has been given by taking an example in which it is decomposed into 8 points in one cycle of the AC component of F power, but
The present invention is not limited to such a configuration, and may be increased or decreased depending on the required accuracy of the ion energy distribution on the measurement target.

In the above embodiment, the susceptor 106 is used.
The parallel plate type etching apparatus for applying RF power has been described as an example, but the present invention is not limited to such a configuration, and any plasma processing apparatus for applying bias RF power to an object to be processed can be used. It can be applied to any device.

[0099]

As described above, in the ion energy measuring method and apparatus according to the present invention, the ion energy of the ions incident on the measuring object is changed by the AC component of the RF power applied to the measuring object. Even if it changes in time, it becomes possible to measure by the measuring means that measures in a time-resolved manner, and the ion energy on the measured surface of the measurement target at each time is calculated from the ion energy at each time measured by the measuring means. By combining them, the ion energy distribution on the surface to be measured on the measurement target to which RF power is applied can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a plasma processing apparatus to which the present invention can be applied.

FIG. 2 is a schematic front view showing a susceptor in the plasma processing apparatus shown in FIG.

FIG. 3 is a schematic front view showing a dummy wafer in the plasma processing apparatus shown in FIG.

4 is a schematic cross-sectional view showing an ion energy detector in the plasma processing apparatus shown in FIG.

FIG. 5 is a schematic explanatory view showing points at which the ion energy of ions in the sensor according to the present embodiment is time-resolved.

FIG. 6 is a schematic explanatory view showing the ion energy of ions in the sensor after time resolution according to the present embodiment.

FIG. 7 is a schematic explanatory diagram showing the ion energy of ions in the simplified time-resolved sensor according to the present embodiment.

FIG. 8 is a schematic explanatory diagram showing ion energy on a dummy wafer which is time-resolved according to the present embodiment.

FIG. 9 is a schematic explanatory view showing ion energy on a dummy wafer which is time-resolved according to the present embodiment.

FIG. 10 is a schematic explanatory view showing ion energy on a dummy wafer which is time-resolved according to the present embodiment.

FIG. 11 is a schematic explanatory view showing an ion energy distribution on a dummy wafer according to the present embodiment.

[Explanation of symbols]

102 processing chamber 104 processing container 106 susceptor 116 high frequency power supply 124 upper electrode 132 gas supply source 150 ion energy detector 152 grid 154 sensor 156 electrode plate 162 Variable DC power supply 166 ammeter 168 Self-bias voltage extraction circuit W dummy wafer Wa through hole

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-213374 (JP, A) International Publication 91/9150 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01J 49/44-49/48 H01J 37/04 H01J 37/244 H01L 21/302

Claims (13)

(57) [Claims] The method according to claim 1, wherein at least comprising measuring system collector means disposed at a position at a predetermined distance with respect to the dummy wafer, the ion energy measurement method for measuring an ion energy on the dummy wafer affected by the electric field of the RF power Yes : a plurality of the RF powers of ions that have passed through the dummy wafer
Calculating a first step of measuring time-resolved manner by the collector means of ion energy in the phase, the ion energy on the dummy wafer on the basis of the measured value of the ion energy at the plurality of phases of
A second step of obtaining a result, the second by combining the energy of ions obtained in step, characterized in that it comprises at least a third step of obtaining an ion energy distribution on the dummy wafer, the ion energy measurement method. 2. The measurement system further comprises the dummy wafer.
Ha and comprises a sequential plurality of grid means disposed between said collector means, said first step, said by changing the DC voltage applied to the grid means, said ion current passing through the grid means by detecting the change, the Damiu
And measuring the <br/> ion energy in the RF power of a plurality of phases are applied to the E c, the ion energy measuring method according to claim 1. Wherein the DC voltage applied to the grid means is characterized in that a reference potential is given by the self-bias voltage generated in the dummy wafer by the application of the RF power, the ion energy according to claim 2 Measuring method. 4. The method according to claim 2, wherein the first step further includes a step of selecting a peak value from the measured ion energy and obtaining a peak distribution based on the peak value. Ion energy measurement method. Wherein said second step is characterized in that the specific value of the peak values selected at least in the first step and the measurement system, measures the ion energy on the dummy wafer, claim The ion energy measuring method according to any one of 1, 2, 3 and 4. By 6. sequentially at least comprising measuring system and a plurality of grid means disposed between the collector means and the dummy wafers and the collector means which is disposed at a position at a predetermined distance with respect to the dummy wafer, RF power An ion energy measuring method for measuring ion energy on the dummy wafer affected by an electric field, comprising : changing a DC voltage applied to the grid means; and changing an electric current of the ions passing through the grid means. is detected by the collector means, steps and measuring the ion energy in the RF power of the plurality of phases in the collector means; on the dummy wafer on the basis of the specific value of the measurement system and its measured the ion energy and characterized in that it consists of; and determining an ion energy distribution That, ion energy measurement method. Wherein said RF to RF power in the processing chamber is irradiated onto the dummy wafer is placed on the mounting table to be applied
An ion energy measuring apparatus for measuring ion energy in a plurality of phases of electric power, comprising : collector means disposed in the mounting table at a position at least a predetermined distance from the dummy wafer;
An ion energy measuring device, characterized in that a plurality of grid means arranged sequentially between the dummy wafer and the collector means are provided. 8. A measurement system comprising at least collector means.
Causes the ions affected by the electric field of the high frequency power to be treated.
A) to measure the ion energy distribution when reaching the physical body
On-energy measurement method: By using the measurement system, the high frequency power can be applied to a plurality of phases.
Measuring the ion energy of the The ion energy measured at the plurality of phases
The ion energy distribution based on
And A method for measuring ion energy, comprising: 9. A step for obtaining the ion energy distribution
Is the ion measured at the plurality of phases.
Calculating the energy, The ion energy at the calculated plurality of phases
The step of synthesizing 9. Ion energy according to claim 8, characterized in that
Lugie measuring method. 10. The mounting table in the processing chamber is the measurement system.
It is buried in the
The described ion energy measuring method. 11. The ion engine in the plurality of phases
The steps for measuring energy are placed on the table described above.
The ion energy of the ions passing through the dummy wafer
The method according to claim 10, which is a step of measuring.
The described ion energy measuring method. 12. The measurement system includes a collector and a grid.
Have a Measuring the ion energy in the plurality of phases
Changing the DC voltage applied to the grid.
Change in the amount of ions passing through the grid is detected.
9. The method according to claim 8, further comprising the step of issuing.
11. The method for measuring ion energy according to any one of 11
Law. 13. Claims 1 to 6 and claims 8 to 12
Use the ion energy measurement method described in any one of
And controlling the ion energy distribution in the processing chamber,
A special feature is that the object to be processed in the processing chamber is subjected to plasma processing.
Plasma processing equipment to collect.