JPH11201899A - Measuring device and treating device of density distribution of particle and plasma treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform uniform treatment within a surface when performing such as film formation and etching to a semiconductor wafer using, for example, plasma. SOLUTION: Infrared semiconductor laser beams are applied to a rotary mirror 22 from a laser beam output part 20 being provided outside a treatment room 1 for generating plasma via a mirror 23. By changing the rotary position of the rotary mirror 22, for example, four light paths L1-L4 are formed in the treatment room 1 via, for example, mirrors M1-M4, the amount of attenuation of laser beams for each light path is detected by a detection part 3, and the density distribution of particles such as CF2 radical, CF radical, and SiF4 molecule in the arrangement direction of the light path is measured. Based on the measurement result, process conditions such as a pressure, a flow rate, and a microwave power are controlled in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring, for example, the density distribution of particles in a gas using laser light, a processing apparatus for processing, for example, a semiconductor wafer, and a plasma processing method.

[0002]

2. Description of the Related Art Semiconductor wafers (hereinafter referred to as "wafers")
In the manufacturing process, there is a plasma processing technique of performing film formation and etching using plasma, and as a method of generating plasma, E cyclotron resonance using electron cyclotron resonance is used.
There are a CR system, a parallel plate system in which a pair of flat plates are opposed to each other and electric power is applied therebetween, a helicon wave system, an ICP system, and the like. It is considered that radicals in the plasma play an important role in such plasma processing. For this reason, for example, Japanese Patent Application Laid-Open No. 9-199485 discloses that the density of radicals in a processing chamber is measured by detecting a change in the spectrum of infrared semiconductor laser light, and the output of microwaves is controlled based on the measured value. The technology is described.

[0003]

However, even if, for example, the radical density at the center of the wafer is measured and the film thickness and the etched shape at the center can be obtained with high accuracy, the radical density at other parts on the wafer is taken into consideration. If not, there is a problem that it cannot be said to be a sufficient control method from the viewpoint of securing in-plane uniformity. For example, if the radical density at the center of the wafer locally deviates from a predetermined value and the radical density at another portion is a predetermined value, the control is rather disturbed by local information, resulting in poor in-plane uniformity. There is also concern that it will be.

[0004] Further, by utilizing the fact that a laser beam is irradiated on the plasma and the molecules absorb the light to emit fluorescence (this method is generally called LIF method; Laser Induced Fluorescence).
It is also conceivable to measure the fluorescence and estimate the radical density based on the measured value, but this method cannot perform accurate process control because the reliability of the measured value is not high. There is a problem in that it is not possible to estimate the density of a radical that is not or does not shine.

The present invention has been made under such circumstances, and an object of the present invention is to measure the density distribution of particles such as radicals. An object of the present invention is to provide a device that can contribute to improvement in performance. Another object of the present invention is to
An object of the present invention is to provide an apparatus capable of performing processing with high in-plane uniformity on a substrate to be processed by controlling process conditions based on a density distribution of particles such as radicals. Still another object of the present invention is to provide a plasma processing method capable of performing processing with high in-plane uniformity on a substrate to be processed by controlling process conditions based on a density distribution of particles such as radicals. It is in.

[0006]

According to the present invention, there is provided a measuring chamber to which a fluid is supplied, a laser light output section provided outside the measuring chamber, and a laser beam from the laser light output section. Reflects light,
A mirror section including a movable mirror whose position can be varied so as to form a plurality of optical paths of laser light in the measurement chamber according to the position; and a laser beam having passed through the plurality of optical paths. A detector for sequentially receiving light and detecting the density of specific particles in the measurement chamber based on the amount of laser light attenuation for each optical path, wherein the movable mirror is sequentially set at each position. ,
An apparatus for measuring the density distribution of particles, wherein the laser light from the laser light output section is sequentially passed through the plurality of optical paths, and the density distribution of the particles is determined based on the density of the particles in each optical path. It is in.

In the present invention, for example, the movable mirror is constituted by a rotatable rotary mirror, and the rotary mirror is sequentially set at each rotation position to transmit the laser light from the laser light output section. The light can be sequentially passed through the plurality of optical paths. Further, the mirror portion may be configured to include a plurality of fixed mirrors for reflecting the laser light from the rotating mirror and forming respective optical paths. Further, it is also possible to provide a plurality of mirrors for reflecting the laser light, which has passed through each optical path in the measurement chamber, to the detection unit.

Another invention provides a processing chamber for processing a substrate to be processed with a processing gas, a laser light output unit provided outside the processing chamber, and a laser light output from the laser light output unit. A mirror portion including a movable mirror that reflects the laser light and whose position can be changed so as to form a plurality of optical paths of the laser light in the processing chamber according to the position; The laser light that has passed through a plurality of optical paths sequentially formed by being set at the position is received, and the density of specific particles in the processing gas is determined for each optical path based on the amount of attenuation of the laser light. A particle density detector for detecting, and a means for controlling processing conditions for processing performed on a substrate to be processed in a processing chamber based on a particle density of each optical path detected by the particle density detector. A processing device comprising:

In this case, the plurality of optical paths are arranged along the surface direction of the substrate to be processed. The processing chamber is for processing a substrate to be processed by, for example, plasma, and the specific particles are, for example, radicals or molecules. Note that the treatment performed with plasma includes, for example, a film formation treatment and an etching treatment.

Still another aspect of the present invention is a method of generating plasma in a processing chamber and performing processing on a substrate to be processed in the processing chamber by the plasma. The laser light is passed, the attenuation of the laser light is determined for each optical path, the density distribution in the plane direction of the substrate to be processed is determined for specific particles in the plasma based on these attenuations, A plasma processing method characterized in that processing conditions are controlled based on a density distribution.

[0011]

1 and 2 show an embodiment in which the measuring apparatus of the present invention is configured as an apparatus for measuring radicals in a processing chamber of an ECR (Electron Cyclotron Resonance) plasma apparatus. . First, a portion related to the plasma apparatus will be briefly described. In FIG. 1, reference numeral 1 denotes a processing chamber having a square cross section (corresponding to a measuring chamber in the claims). A mounting table 11 for mounting horizontally is provided. A waveguide 12 is connected to the center of the upper surface of the processing chamber 1.
From 2, microwaves and, for example, Ar (argon) gas are introduced into the processing chamber 1.

Above the mounting table 11, a ring-shaped gas supply unit 13 having a gas hole (not shown) is provided along the circumferential direction so as to face the mounting table 11, and the gas from the gas supply unit 13 is supplied with gas. It is designed to squirt inward from the hole. Exhaust pipes 14 are connected to the bottom of the processing chamber 1 at, for example, two places.
5 and 16 are provided.

Next, a portion related to the measuring device will be described. An infrared semiconductor laser light output device constituting a laser light output section 20 for outputting an infrared semiconductor laser light is provided outside the processing chamber 1. A mirror section 2 for forming four optical paths L1 to L4, which are optical paths of the laser light output from the optical output section 20, and a laser light from the laser light output section, receiving the laser light and detecting its intensity; A detector 3 for obtaining the density (absolute density) of radicals in the processing chamber 1 based on the amount of attenuation of the laser light caused by passing through the optical path in the processing chamber 1; and the processing chamber through the optical paths L1 to L4. Four light-receiving-side mirrors 4 for reflecting the laser light emitted from 1 to the detection unit 3
1 to 44 are provided. A portion of the side wall of the processing chamber 1 that becomes the optical path L1 to L4 of the laser beam is made of, for example, transparent glass.

As shown in FIG. 3, the mirror 2 is provided with a rotating mirror 22 which is a movable mirror rotatable about a substantially vertical axis by a rotating mechanism 21, and a laser beam output from a laser beam output section 20. A mirror 23 for reflecting and entering the rotating mirror 22; and a mirror (light emitting) for reflecting the laser light entered from the mirror 23 via the rotating mirror 22 to form the four optical paths, respectively. Side mirror) M
1 to M4.

The detecting section 3 calculates the intensity I (νc) of the received laser beam having the wave number νc, and obtains the intensity I (νc).
It has a function of calculating the number (absolute density) of radicals based on c) and the intensity I ₀ (νc) of the laser light reflected on the light-emitting side mirror which is known in advance. In particular,
For example, it is obtained based on the following (Equation 1).

(Equation 1) Where n is the absolute density (pieces / cm ³ ), vc is the measured wave number (cm ^-1 ), and S is the line strength (c
m / unit), T is the translation temperature (K) of the molecule, M is the mass of the molecule (g / mol), L is the absorption length (optical path length in the processing chamber 1: cm), and νc is the absorption of CF ₂ Wave number eg 11
32.5322 cm ^-1 is used. This equation is an equation obtained assuming that the shape of the spectrum is Doppler line shave.

Next, the operation of the above embodiment will be described. A mirror magnetic field is formed by the electromagnetic coils 15 and 16 so that the lines of magnetic force pass almost vertically over the entire surface of the wafer W. Electron cyclotron resonance occurs due to the microwave M and the magnetic field, and Ar gas and gas from the gas supply unit 13 such as C ₄ F ₈ gas is plasma. The area surrounded by the dotted line in FIG. 1 is an area where a so-called dark plasma shining blue and white is generated.

[0017] The laser beam mirror 23 by the laser beam output section 20, rotating mirror 22, may be set the rotational position of the rotating mirror 22 so as to pass through the optical path L1 via the mirror M1, the absorption wave number of CF ₂ radical There is 112.7
532 cm ^-1 infrared semiconductor laser light to laser light output unit 2
Output from 0. Thereby, the laser light from the laser light output unit 20 passes through the optical path L1 and is received by the detection unit 3 via the mirror 41. The detecting section 3 detects the intensity of the received laser light and obtains the density (absolute density) of CF ₂ radicals corresponding to the amount of attenuation of the laser light.

Next, the rotating position of the rotating mirror 22 is set so that the optical path L2 is formed, that is, the laser light from the mirror 23 passes through the optical path L2 via the rotating mirror 22 and the mirror M2. To determine the density of CF ₂ radicals. Further, the rotating mirror 22 is sequentially rotated to similarly obtain the density of CF ₂ radicals corresponding to the optical paths L3 and L4. Now, the density obtained here is the average density in each optical path L1 (L2, L3, L4) in the processing chamber 1,
For example, as shown in FIG. 4A, assuming a density distribution in the processing chamber 1 (black circles and white circles have the same density, and black circles and white circles have different densities). The density distribution in the planar direction of the processing chamber 1 can be obtained by computer analysis by performing an appropriate calculation based on the continuity of the data.

If the processing chamber 1 is cylindrical, it can be obtained by performing Abel transform or the like. That is, assuming that the concentric densities are equal as shown in FIG. 4B, (Equation 2) holds.

[0020]

(Equation 2) FIG. 4B shows a state in which the ring-shaped region is concentrically divided into a plurality of (N) ring-shaped regions, and the radical density is equal in each of the ring-shaped regions, and light is transmitted through the inside as indicated by an arrow. This is shown conceptually. I (y) is a value obtained by integrating the average density obtained at each y position from the center of the processing chamber to the wall surface along the Y axis, r is a radial distance from the center of the processing chamber,
ε (r) is the density distribution in the radial direction, and R is the radius of the processing chamber (the radical density is treated as zero on the wall surface of the processing chamber). By inversely transforming Equation 2, Equation 3 is obtained, and the radial density distribution is obtained.

[0021]

(Equation 3) Therefore, if the direction of the optical path L1 (L2, L3, L4) is the X direction, the density distribution of CF ₂ radicals in the direction orthogonal to the optical path L1 (L2, L3, L4), that is, in the Y direction can be obtained. More specifically, the plot (value of the average radical density obtained along each optical path) for obtaining I (y) is only the number of optical paths, and is four in the above case.
I (y) is obtained by increasing the value of y by interpolating these values into a smooth curve. Therefore, if the number of optical paths is increased, I (y) can be determined more accurately. And this I
Differentiating (y) with y and integrating into equation (3) gives ε
(R) is obtained. In the present invention, an optical path may also be formed in a direction orthogonal to the optical path, and the density of points where the optical paths in the X and Y directions cross may be obtained by a method similar to computer tomography (tomography). .

According to this embodiment, the processing chamber 1 in which plasma is generated uses the rotating mirror 22 and a plurality of optical paths are formed in the processing chamber 1 corresponding to the rotation position. The density distribution of radicals can be measured. Therefore, the state of the plasma can be checked, and furthermore, C
F ₂ radicals fluorinated carbon films - are related to (fluorocarbon Bonn film) deposition and for example, an etching mechanisms silicon oxide film, and the in-plane uniformity of the density of CF ₂ radicals and the film thickness and the machining shape Is considered to be related, and for example, by feeding back a measurement result to a process condition as in an embodiment described later, it is possible to help improve the uniformity of processing.

It is theoretically possible to make the output window of the output unit 20 face the processing chamber 1 and move the laser light output unit 20 in the Y direction. However, the laser light output unit 20, for example, an infrared semiconductor laser light output device Is a large and heavy object having a size of about 2 m. Therefore, assembling a moving mechanism for moving the large-sized object requires a very large moving mechanism and a large laser beam output unit. It is impossible in terms of space and cost, and cannot be implemented in practice.

However, on the side that detects the laser beam,
For example, the detector 3 may be moved in the Y direction along the rail 3a as shown in FIG. 5 without using the mirrors 41 to 44. The laser beam output unit 20 and the rotating mirror 22 are combined without using the mirrors M1 to M4 and the mirror 23, and the rotating mirror 22 is placed at the position of the mirror 23 in FIG. A plurality of optical paths may be formed in the mirror, or a mirror 26 is placed on a base 25 movable in the Y direction along a guide rail 24 as shown in FIG. By moving the mirror 26 in the Y direction to change the position of the mirror 26, the optical paths L1 to L4 may be formed. In this case, the mirror 26 corresponds to a movable mirror. Note that the number of optical paths is not limited to four.

In the present invention, the density distribution of not only CF ₂ radicals but also other radicals such as CF and CF ₃ radicals may be measured, and particles other than radicals, such as ions, atoms and molecules, are measured. Alternatively, it is also possible to measure not only particles in a gas but also particles such as ions, atoms and molecules in a liquid. The laser light is not limited to infrared semiconductor laser light, but may be laser light in a visible region or an ultraviolet region, for example. In the following, plasma is generated using C ₄ F ₈ gas,
Example 1-3 The results of measuring the density of radicals of CF _2, also to respectively described in density Example 4 and 5 the results of measurement for the CF radicals to generate plasma further using SiF ₄ gas SiF Example 6 shows the results measured for the density of the _four molecules.

(Embodiment 1) In the apparatus shown in FIG.
For example, a square tube having a side of 50 cm and a height of 50 cm is used.
It was placed about 13 cm below the point. The microwave frequency and power are 2.45 GHz and 100, respectively.
0 W, and the magnetic field was 87 at the ECR point.
The intensity was set to 5 G (Gauss) and a mirror magnetic field was formed so that plasma (dense plasma) having a diameter of about 25 cm was confined on the wafer W. C ₄ F ₈
The gas was introduced from the gas supply unit 13 at a flow rate of 60 sccm.

The pressure in the processing chamber 1 is 4.0 Pa,
The density distribution of CF ₂ radicals was set at 1.3 Pa and 0.4 Pa through a laser beam of 112.7532 cm ⁻¹ , which is the absorption wave number of CF ₂ radicals, at a position 1 cm above the wafer W under each pressure. Was obtained, the result shown in FIG. 7 was obtained. From this result, the higher the pressure, the higher the density of CF ₂ radicals and the higher the density near the inner wall of the processing chamber 1 than on the surface of the wafer W, and the uniformity of the density on the surface of the wafer W It can be seen that the property is higher as the pressure is lower.

(Embodiment 2) The pressure in the processing chamber 1 is set to 1.3 P
a, and the microwave power is 500 W, 1000 W
W and 2500 W were set, and the density distribution of CF ₂ radicals was determined under each condition. The results shown in FIG. 8 were obtained. Other conditions are the same as in the first embodiment. From this result, it was found that the higher the microwave power, the lower the density of CF ₂ radicals. The uniformity of the density on the surface of the wafer W was almost the same under any conditions.

(Embodiment 3) The pressure in the processing chamber 1 is set to 1.3 P
a, the microwave power is set to 1000 W, respectively, and C
The flow rate of the ₄ F ₈ gas is 30 sccm, 60 sccm and 1 sccm.
50 sccm are set, and CF is set under each condition.
_When the density distribution of the _two radicals was determined, the results shown in FIG. 9 were obtained. Other conditions are the same as in the first embodiment. From this result, it was found that when the flow rate of the C ₄ F ₈ gas was increased, the density of the CF ₂ radical was increased, and the flow rate affected the uniformity of the density on the wafer W surface. Note that wafer W
The reason why the density of CF ₂ radicals is higher near the inner wall surface of the processing chamber 1 than on the surface is that separation of CF ₂ radicals is promoted on the wafer W surface due to electric shock of plasma, In the vicinity, it is considered that one factor is that a reaction product attached to the wall surface reacts with fluorine to generate CF ₂ radicals.

(Example 4) The density distribution of CF radicals was measured in the same manner as in Example 1 except that the density distribution of CF radicals was obtained through the laser beam of 1108.6702 cm ^-1 which is the absorption wave number of CF radicals. The pressure dependence of the distribution was determined. In this case as well, the pressure in the processing chamber 1 is set at three values, 4.0 Pa, 1.3 Pa, and 0.4 Pa, as in the first embodiment. The results are as shown in FIG. From this result, it can be seen that the higher the pressure, the lower the density of CF radicals, which is opposite to the case of CF ₂ radicals compared to Example 1. The uniformity of the density on the surface of the wafer W is higher at a pressure of 1.3 Pa than at pressures of 0.4 Pa and 4.0 Pa.

Example 5 The density distribution of CF ₂ radicals was measured in the same manner as in Example 2 except that the density of CF radicals was determined by passing a laser beam having an absorption wave number of CF radicals of 1108.6702 cm ^−1. Of microwave power dependence. Also in this case, the microwave power was changed to the third embodiment.
In the same manner as in the above, three types of 500 w, 1000 w and 2500 w are set. The results are as shown in FIG. From this result, it can be seen that the higher the microwave power, the higher the density of CF radicals, which is opposite to the case of CF ₂ radicals as compared with Example 3. Further, as the microwave power increases, the density of CF radicals near the wall increases as compared with the vicinity of the center of the wafer W. This is because of the reason discussed in the previous embodiment 3 and the C from the upper part of the processing chamber 1.
It is possible that the F radical is wrapped around. Further, the wafer W
The uniformity of the density on the surface is that the microwave power is 2
1000 w and 500 w are higher than 500 w. From the above results, it was found that the dependence of the radical density on the pressure and the microwave power depended on the radical species, and the reason was that the degree of radical separation and the degree of radical generation on the wall surface due to the electric shock of plasma. It is presumed that it is different depending on the radical.

Example 6 SiF ₄ gas was introduced into the processing chamber 1 at a flow rate of 90 sccm instead of C ₄ F ₈ gas, and the pressure in the processing chamber 1 was set to 1.3 Pa. Then, the microwave power is set to 0 w, 1000 w, 1500 w and 25 w
Set four ways of 00W, through a laser beam of 1032.131Cm ^-1 is the absorption wave number of SiF ₄ molecule, SiF ₄
The microwave power dependence of the molecular density distribution was determined. Other conditions are the same as in the first embodiment. The results are as shown in FIG. From this result, the higher the microwave power,
It can be seen that the dissociation of SiF ₄ has progressed and the overall SiF ₄ molecular density has decreased. When microwave power is applied, the molecular density at the center is higher than that at the wall surface. This is based on the fact that the closer to the center of the wafer W, the higher the plasma energy is, and the dissociation of SiF ₄ is promoted. It is considered something. The present inventor has proposed that SiF
_Although the value of the line strength S corresponding to the above wave number in _four molecules was not known, S was obtained as follows. That is, when no microwave power is applied, S
Since the iF ₄ gas is regarded as an ideal gas and the pressure, temperature and volume are known, the density n of SiF ₄ can be obtained from the equation of state of the gas (PV = nRT). Under the condition of 1.3 Pa at room temperature, n was 3.2 × 10 ¹⁴ cm ⁻³ . Therefore, if k (νc) was obtained at this time, S was obtained from the above equation (1), and S was 3.5 × 10 ⁻²⁰ cm / piece. If S is known in this way, n can be obtained by obtaining K (νc) when microwave power is applied.

Next, a plasma processing apparatus utilizing ECR, which is an embodiment of a substrate processing apparatus incorporating the above-described measuring apparatus, will be described with reference to FIGS.
The apparatus includes a vacuum vessel 2 including a first vacuum chamber 51 having a cylindrical shape and a second vacuum chamber 52 having a transmission window 52a for laser light. It is configured to be introduced into the vacuum vessel 2 from the upper end of the vacuum vessel 2 via the transmission window 54 and the transmission window 55. 56, 5
Reference numeral 7 denotes a main electromagnetic coil and an auxiliary electromagnetic coil, respectively. These electromagnetic coils 56 and 57 form a mirror magnetic field. The electromagnetic coil may be provided so as to wind around the waveguide 54. Reference numerals 61 and 62 denote a gas supply nozzle and a ring-shaped gas supply unit, respectively. For example, an Ar gas is supplied from the gas supply nozzle 61, and when a film is formed from the gas supply unit 62, for example, C ₄ F ₈ gas and C ₂ H ₄ gas.
Each of the F-based gases is supplied. 63 is a wafer mounting table, 6
Reference numeral 4 denotes an exhaust pipe, and 65 denotes a bias power supply unit for applying bias power to the mounting table 63.

The above-described radical measuring device is provided outside the vacuum vessel 2 as shown in FIG. 9, for example, four optical paths L1 extending from the center end of the wafer W to the peripheral edge thereof.
To L4 are formed. In FIG. 14, reference numeral 31 denotes a radical density detecting unit, 32 denotes a radical density distribution analyzing unit, and the density distribution analyzing unit 32 determines the density based on the radical density for each of the optical paths L1 to L4 detected by the radical density detecting unit 31. Has a function to analyze the distribution. Analyzing the density distribution means, for example, finding the difference between the maximum value and the minimum value of the radical density for each of the optical paths L1 to L4, or creating a graph of the density distribution described above. This is useful for changing the process conditions based on the difference, and the latter case is used for analyzing the state of the plasma later.

FIG. 15 is a diagram showing an apparatus for controlling the process conditions in real time based on the result analyzed by the density distribution analyzer 32 in the plasma processing apparatus shown in FIG. In FIG. 15, 7 is a main control unit, and 71 is a pulse generator for pulse-modulating the power of the high-frequency power supply unit 53. Assuming that the microwave is pulse-modulated with a pulse having a certain duty ratio, the main control unit 7 controls the control signal according to the difference Δd between the maximum value and the minimum value of the radical density obtained from the density distribution analysis unit 32, for example. Is output to the pulse generator 71 to adjust the duty ratio. The microwave is guided, for example, in the TM mode or the TE mode.

The electron temperature of the plasma can be controlled by pulse-modulating the microwave, thereby controlling the density of radicals, for example, CF ₂ radicals.
If the duty ratio is controlled based on the specific radical density distribution, the radical density in the wafer surface can be finely controlled, and as a result, the film thickness on the wafer W and the processed shape of etching can be highly uniform in the plane. Nature can be secured. In this example, C ₄ F ₈ gas and C
_The fluorinated carbon film is obtained by the ₂ H ₂ gas, and the in-plane uniformity of the film thickness is improved. As a method of controlling the duty ratio, a control signal for changing the duty ratio may be output when the radical density exceeds a predetermined upper limit set value or becomes lower than the lower limit set value. , May be combined with the above-described control. Further, the control of the microwave is not limited to the control of the duty ratio, and the power (power value) and the wall surface temperature may be controlled.

Further, a control signal output from the main control unit 7 based on the analysis result of the density distribution analysis unit 32 is supplied to current control units 72 and 73 for controlling the electromagnetic coils 56 and 57, respectively, to adjust the excitation current. The intensity of the magnetic field and the shape of the lines of magnetic force may be changed. Further, the control signal may be given to a flow rate adjusting section 72 for adjusting the flow rate of the gas sent to the gas supply section 62 to adjust the total flow rate and the mixing ratio of the gas, or provided to the exhaust pipe 64. Alternatively, the pressure in the processing chamber 1 may be adjusted by adjusting the opening degree of the displacement adjusting unit, for example, the butterfly valve. And the bias power supply 6
As for 5, the power value may be controlled, or when pulse modulation is performed by the pulse generator 76, the duty ratio may be controlled via the pulse generator 76 by the control signal. Is particularly effective when etching a thin film on the wafer W.

As described above, by measuring the density distribution of radicals in the plane direction of the wafer W and controlling the process conditions such as microwave, pressure and gas flow rate in real time based on the measurement results, the density distribution of radicals can be finely divided. Can be controlled. Here, the processing state of the wafer W, for example, the uniformity of the film thickness and the uniformity of the etching process are related to the radicals in the plasma. When the distribution changes, fine control such as changing the target value based on the density distribution can be performed, so that the in-plane uniformity of the plasma processing can be improved, and the diameter of the wafer increases. Among them, this is an effective method for improving the throughput. Here, the present invention is not limited to the formation of a fluorinated carbon film, but, for example, SiF ₄ gas is supplied from the gas supply unit 62 and oxygen gas and argon gas are supplied from the gas supply nozzle 61 into the vacuum vessel 2. When introducing and forming a SiOF film, S
The density of iF ₄ molecules may be detected (the density of SiF ₄ molecules can be measured as described in Example 6), and the processing conditions may be controlled based on the detection result. When etching the SiO ₂ film with a CF-based gas, S
Since iF ₄ is generated, etching may be performed by controlling the processing conditions based on the density of SiF ₄ .

In the above, the present invention relates to a helicon wave type other than ECR, a parallel plate type,
It can also be used for (inductively coupled plasma) type plasma processing, and can be applied to plasma processing other than film formation and etching, such as ashing (ashing) of resist. In addition to the plasma processing, the present invention can be applied to other apparatuses for processing a substrate using a processing gas, such as a thermal CVD apparatus.

[0040]

According to the measuring apparatus of the present invention, since a plurality of optical paths are formed in the measuring chamber by moving the mirror, radicals, ions, atoms, molecules or the like in the measuring chamber can be formed without a large-scale apparatus. The density distribution of the particles can be measured, and for example, there is an effect that the state of the plasma can be grasped more accurately.

According to the processing apparatus of the present invention, the density distribution of radicals and the like in the processing chamber is measured by using the above-described measuring apparatus, and the process conditions are controlled based on the result. As a result, in-plane uniformity of processing on the substrate can be improved.

Further, according to the plasma processing method of the present invention,
Since the process conditions are controlled based on the radical density distribution, the state of the plasma can be finely controlled, and the in-plane uniformity of the processing on the substrate can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing an embodiment of a measuring device of the present invention.

FIG. 2 is a cross-sectional plan view showing an embodiment according to the measuring device of the present invention.

FIG. 3 is a perspective view showing a movable mirror used in the embodiment.

FIG. 4 is an explanatory diagram showing an example of a model for estimating a radical density distribution.

FIG. 5 is a cross-sectional plan view showing another embodiment of the measuring device of the present invention.

FIG. 6 is a cross-sectional plan view showing still another embodiment of the measuring device of the present invention.

FIG. 7 shows the position and C in the processing chamber when the pressure is changed.
FIG. 4 is a characteristic diagram showing a relationship with F ₂ radical density.

FIG. 8 is a characteristic diagram showing a relationship between a position in a processing chamber and a CF ₂ radical density when microwave power is changed.

FIG. 9 is a characteristic diagram showing a relationship between a position in a processing chamber and a CF ₂ radical density when a gas flow rate is changed.

FIG. 10 is a characteristic diagram showing a relationship between a position in a processing chamber and a CF radical density when a pressure is changed.

FIG. 11 is a characteristic diagram showing a relationship between a position in a processing chamber and a CF radical density when microwave power is changed.

FIG. 12 is a characteristic diagram showing a relationship between a position in a processing chamber and a SiF ₄ molecular density when microwave power is changed.

FIG. 13 is a vertical sectional side view showing an embodiment of the processing apparatus of the present invention.

FIG. 14 is a cross-sectional plan view showing an embodiment according to the processing apparatus of the present invention.

FIG. 15 is a block diagram showing an embodiment according to the processing apparatus of the present invention.

[Description of Signs] 1 Processing chamber 2 Mirror unit W Semiconductor wafer 20 Laser light output unit 22, 26 Rotating mirror 25 Base M1 to M4, 23 Mirror 3 Detecting unit 41 to 44 Mirror L1 to L4 Optical path 5 Vacuum container 53 High frequency power supply Unit 61 Gas nozzle 62 Gas supply unit 65 Bias power supply unit 31 Radical density detection unit 32 Density distribution analysis unit 7 Main control unit 71, 76 Pulse generation unit 72, 73 Current control unit 74 Flow control unit 75 Pressure adjustment unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masafumi Ito 3-1802 Umedaoka, Tempaku-ku, Nagoya City, Aichi Prefecture New Corp Ueda II305 (72) Inventor Nobuo Ishii 5-6-1 Akasaka, Minato-ku, Tokyo Tokyo Inside Electron Co., Ltd. (72) Inventor Satoshi Kawakami 1-2-4, Machiya, Shiroyama-cho, Tsukui-gun, Kanagawa Prefecture Inside the Tokyo Electron Tohoku Co., Ltd. Sagami Office

Claims (10)

[Claims] 1. A measuring chamber to which a fluid is supplied, a laser light output unit provided outside the measuring chamber, and a laser light reflected from the laser light output unit, and reflected at the position. A mirror including a movable mirror whose position can be changed so as to form a plurality of optical paths of laser light in the measurement chamber in response to the request.
A detecting unit for sequentially receiving the laser light that has passed through the plurality of optical paths, and detecting the density of specific particles in the measurement chamber based on the amount of attenuation of the laser light for each optical path. The movable mirror is sequentially set at each position, the laser light from the laser light output unit is sequentially passed through the plurality of optical paths, and the particles are determined based on the density of the particles in each optical path. An apparatus for measuring the density distribution of particles, wherein the density distribution is determined. 2. The movable mirror is constituted by a rotatable mirror provided rotatably. The rotatable mirror is sequentially set at each rotation position, and the laser light from the laser light output section is transmitted. The apparatus for measuring the density distribution of particles according to claim 1, wherein the particles are sequentially passed through the plurality of optical paths. 3. The mirror section includes a plurality of fixed mirrors for reflecting laser light from the rotating mirror to form respective optical paths.
The apparatus for measuring the density distribution of particles according to claim 2, comprising: 4. A mirror according to claim 1, wherein a plurality of mirrors are provided for reflecting the laser light, which has passed through each optical path in the measurement chamber, to the detection unit. A device for measuring particle density distribution. 5. A processing chamber for processing a substrate to be processed with a processing gas, a laser light output unit provided outside the processing chamber, and laser light from the laser light output unit. And a movable mirror whose position can be changed so as to form a plurality of optical paths of laser light in the processing chamber according to the position.
And the movable mirror is set at each position to receive laser light that has passed through a plurality of optical paths sequentially formed, and performs processing based on the amount of attenuation of the laser light for each optical path. A particle density detector for detecting the density of specific particles in the gas; and a process performed on the substrate to be processed in the processing chamber based on the particle density of each optical path detected by the particle density detector. A processing unit for controlling processing conditions for the processing. 6. The processing apparatus according to claim 5, wherein the plurality of optical paths are arranged along a surface direction of the substrate to be processed. 7. The processing apparatus according to claim 5, wherein the processing chamber is for processing the substrate to be processed by plasma, and the specific particles are radicals or molecules. 8. The process of processing a substrate to be processed by plasma means that a film is formed on the substrate to be processed.
The processing device according to the above. 9. The processing apparatus according to claim 7, wherein processing the substrate to be processed with plasma means performing etching on the substrate to be processed. 10. A method for generating plasma in a processing chamber and processing a substrate to be processed in the processing chamber by the plasma, wherein a plurality of optical paths are formed in the processing chamber and laser light is applied to these optical paths. The laser beam is passed, the attenuation of the laser light is determined for each optical path, the density distribution of the specific particles in the plasma in the surface direction of the substrate to be processed is determined based on the attenuation, and the density distribution is determined based on the determined particle density distribution. A plasma processing method comprising: