JP2925751B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device having a step of ashing a resist on an object to be processed such as a semiconductor wafer by plasma.

In recent years, H ₂ O components adhering to the wall of a vacuum chamber surrounding a plasma generation region can be removed without lowering the operation rate and throughput of the apparatus, and a stable ashing rate can be obtained. As described above, there is a demand for a method of manufacturing a semiconductor device having a step of performing ashing of a resist.

[0003]

2. Description of the Related Art In a semiconductor manufacturing process, a dry ashing method of a resist using plasma requires efficient ashing of the resist without damaging a semiconductor wafer due to collision of charged particles in the plasma. ing. A downstream ashing process (ashing process downstream of the plasma) that separates the wafer from the plasma to avoid damage to the charged particles
Has been used, and this downstream ashing process mainly uses O ₂ gas. The reactive species that contributes to the ashing reaction in the O ₂ gas downstream ashing process using only O ₂ gas is, for example, an oxygen atom that is a neutral particle, for example, J. MCook, BWBenson:
J. Electrochem. Soc., 130. (1983) 2459.

However, this O ₂ downstream ashing has the advantage that the resist can be ashed only by a chemical reaction, but has problems such as a low ashing rate and a large dependence of the ashing rate on the wafer temperature.

To address these problems, O.D.
₂ and O ₂ + CF ₄ gas downstream ashing process carried out by adding the CF ₄ gas to the gas, C ₂ to O ₂ gas
An O ₂ + C ₂ F ₆ gas downstream ashing process performed by adding F ₆ gas has been proposed.

As described above, O_Two Down mainly using gas
In stream ashing, O _Two CF in plasma
_Four , C_Two F₆ Ash is added when an appropriate amount of gas such as
The rate increases, the activation energy of the ashing reaction
(The dependence of the ashing rate on the wafer temperature is small.
And the effect that the above problem can be solved.
There is. These effects appear only in the plasma
Oxygen atoms are increased that are generated in the plasma
Fluorine atoms contribute to the ashing reaction
It is presumed that. For this reason, the conventional O_Two + CF_Four Gasda
Unstream Ashing Process, O_Two + C_Two F₆ Moth
Downstream ashing processes are often used
Have been.

However, in the ashing process using CF ₄ or C ₂ F ₆ gas, not only the fluorine atoms contribute to the ashing reaction, but also when the underlayer is an oxide film such as SiO ₂ , the ashing process is performed up to the underlayer oxide film. Is also etched, resulting in poor selectivity. Therefore, an O ₂ + H ₂ O gas downstream ashing process (not including fluorine atoms) which has the above-described effects and does not include fluorine atoms or a process capable of preventing etching of an underlying oxide film by fluorine atoms. , O ₂ + H ₂ O + N ₂ gas downstream ashing process (no fluorine atom), O ₂ + H ₂ O
+ CF ₄ gas downstream ashing process (hydrogen atoms can prevent fluorine oxide film etching)
For example, a downstream ashing method using a process gas containing at least O ₂ + H ₂ O gas has been proposed.

[0008]

However, in the above-mentioned conventional downstream ashing method using a process containing at least O ₂ + H ₂ O gas, when this ashing method is used continuously, the vacuum chamber is not used during the previous ashing. At the time of plasma discharge in the ashing process performed in the next step, the H ₂ O component adhering to the wall is turned into plasma together with the process gas and changes the substantial gas mixture ratio, so that irregular control of the set ashing rate occurs irregularly. There was a problem.

As a countermeasure, the plasma discharge region is cleaned by the O ₂ gas plasma only when the ashing rate becomes unstable, but the cleaning time takes about 5 minutes, and the operation rate and throughput of the apparatus are reduced. There was a problem that lowers. Hereinafter, a specific description will be given with reference to the drawings.

FIG. 5 shows the ashing characteristics of the O ₂ + H ₂ O gas downstream ashing process, and shows the change in the ashing rate with respect to the flow rate ratio H ₂ O / (O ₂ + H ₂ O)%.

From FIG. 5, the ashing rate sharply increases when the flow rate ratio H ₂ O / (O ₂ + H ₂ O)% is changed from 0 to 10%, and gradually decreases when it exceeds 10%. You can see that From FIG. 5, O ₂ + H ₂
It can be seen that in the O gas downstream ashing process, it is important to keep the O ₂ + H ₂ O gas mixture ratio in the plasma constant in order to control the ashing rate as set.

Therefore, if the ashing rate does not meet the set value, there is a high possibility that the O ₂ + H ₂ O gas mixture ratio cannot be controlled. Therefore, when the ashing rate is equal to the set value, the plasma emission spectrum and the ashing rate cannot be controlled.
It was compared with the emission spectrum of the plasma when it was reduced. FIG. 6 shows that the O ₂ + H ₂ O gas flow ratio is H ₂ O / (O ₂ +
FIG. 6 is a diagram showing an emission spectrum when an ashing rate (1.3 μm / min) as set in FIG. 5 is obtained by setting H ₂ O)% = 10%. FIG. 7 shows O ₂ + H ₂ O
Although the gas flow ratio was set to H ₂ O / (O ₂ + H ₂ O)% = 10%, the set value of the ashing rate could not be controlled, and the ashing rate was reduced by about 20% from the set value ( It is a figure which shows the emission spectrum figure in the case of 1.0 micrometer / min).

As can be seen from FIGS. 6 and 7, when the ashing rate is as set (FIG. 6) and when the ashing rate is reduced by about 20% from the set value (FIG. 7), the shapes of the emission spectra are different. It turns out that there is. About 20 from the set value
When the% ashing rate is decreased (FIG. 7), the emission intensity of hydrogen atom emission (4861 °) is significantly increased and the OH emission (3063 °) is higher than in the case of the set ashing rate (FIG. 6). It can be seen that the emission intensity of the sample also increased.

[0014] From this, H in the plasma_Two O gas
When the amount is the ashing rate as set (Fig. 6)
It can be estimated that it is increasing. Therefore, FIG._Two 
+ H _Two O gas flow ratio to H_Two O / (O_Two + H_Two O)% = 20
% And set ashes corresponding to Fig. 5
(1.0μm / min)
Show In the case of an abnormality, the emission spectra of FIGS.
Comparing the figures, it turns out that they are almost the same.
You.

Therefore, when the ashing rate is reduced by about 20% from the set value shown in FIG. 7, the gas mixture ratio in the plasma is H ₂ O / (O ₂ + H ₂ O)% = 20%. It is thought that it has become.

Since the gas supply shown in FIGS. 7 and 8 is reliably performed as set, the O ₂ gas and H
_The reason that the mixing ratio of the ₂ O gas cannot be controlled is that H ₂ adhering to the wall of the vacuum chamber surrounding the plasma generation region
The O component remains even after the ashing process and is turned into plasma at the next ashing, and the actual H ₂ O / (O ₂ + H ₂ O)%
Is considered to be larger than the set value. The state where the ashing rate is not stable occurs due to this, particularly when the ashing process is continuously performed.

Therefore, the present invention can remove the H ₂ O component adhering to the wall of the vacuum chamber surrounding the plasma generation area without lowering the operation rate and throughput of the apparatus, and obtain a stable ashing rate. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can perform the above.

[0018]

Since the method of manufacturing a semiconductor device according to the present invention SUMMARY OF THE INVENTION The above objects achieved, in the manufacturing method of a semiconductor device having a step of ashing the resist, at least O ₂ gas using the resist and H ₂ O Ashing with a process gas containing a gas mixture,
Next, the method further includes a step of subjecting the resist to an ashing process with a process gas containing no H ₂ O gas.

The process gas containing the mixed gas according to the present invention includes a mixed gas of O ₂ gas, H ₂ O gas and N ₂ gas,
A mixed gas of O ₂ gas, H ₂ O gas and N ₂ O gas may be used.

The process gas containing no H ₂ O gas according to the present invention includes a mixed gas of O ₂ gas and N ₂ gas and a mixed gas of O ₂ gas and N ₂ O gas.

[0021]

[Function] As a means to constantly stabilize the ashing rate
Is true without sacrificing equipment utilization and throughput.
H attached to the wall surrounding the plasma generation region of the empty chamber
_Two It is desirable to remove the O component. In the present invention, the first
At least O in steps _Two Gas and H_Two Mixed gas of O gas
Ashing with process gas containing
I do. Then, in the next second step, at least H_Two 
Downstream using O-free process gas
Perform the first step while performing the ashing process by
On the wall of the vacuum chamber in the plasma discharge area
H attached _Two O component at least H_Two Does not contain O gas
Since the gas plasma was used for removal, the operation of the equipment was started.
Ashing stable without reducing the rate and throughput
You can get

A more specific description will now be given. In the present invention, the first
In the step, ashing is performed using downstream ashing with a process gas containing at least a mixed gas of O ₂ gas and H ₂ O gas. In the next second step, at least while the H ₂ O gas ashing treatment downstream ashing process using a process gas containing no, H ₂ O adhering to the wall of the vacuum chamber of the plasma discharge region in a first step The components are removed by a plasma of a gas not containing at least H ₂ O gas. This process is performed, for example, in the first step, O ₂ + H ₂
FIGS. 1 to 3 show the results of examining the emission spectrum from the plasma when the ashing process by the O gas downstream process was performed for 54 seconds and the ashing process by the O ₂ gas downstream ashing process was performed for 6 seconds in the second step. Shown in

FIG. 1 is a diagram showing an emission spectrum when ashing is performed in the O ₂ + H ₂ O gas downstream process in the first step. Gas flow ratio at this time _is the _{O 2 / (O 2 + H} 2 O)% = 10%. FIG. 2 is a diagram illustrating an emission spectrum when the O ₂ gas downstream ashing process of the second step is performed, and is a diagram illustrating an emission spectrum when three seconds have elapsed after the start of the second step. In the case of FIG. 2 in the second step, the emission intensity of hydrogen atom emission (4861 °) and the emission intensity of OH emission (3063 °) are significantly reduced as compared with the emission spectrum pattern of FIG. 1 in the first step. You can see that it is.

FIG. 3 is a diagram showing an emission spectrum immediately before the end of the O ₂ gas downstream ashing process in the second step, and is a diagram showing an emission spectrum when 6 seconds have elapsed after the start of the second step. The emission spectrum shown in FIG. 3 is substantially the same as that when only O ₂ gas plasma is emitted. Therefore, it can be seen that the H ₂ O component in the plasma generating portion has been removed by performing the second step.

The ashing rate during the first step was about 1.3 μm / min, and the ashing rate during the second step was about 1.0 μm / min. from these things,
In the first step, the flow rate ratio in FIG. 5 is O ₂ / (O ₂
+ H ₂ O)% = 10%, the ashing process proceeds, and in the second step, the flow rate ratio in FIG. 5 is O ₂ / (O ₂ + H).
₂ O)% = ashing 10% 0% conditions considered to proceed.

Therefore, in the second step, it is considered that the ashing process and the cleaning of the plasma generating portion are proceeding simultaneously. Under the above conditions, about 1.26μ on 6 inch wafer
The applied resist could be removed in 60 seconds. On the other hand, when only the O ₂ + H ₂ O gas downstream ashing process is used, the same sample can be ashed in 58 seconds. Therefore, a stable process can be supplied by reducing the throughput by about 3%.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
FIG. 4 is a schematic diagram showing a downstream ashing apparatus. In FIG. 4, 1 is a wafer, 2
Is a stage on which the wafer 1 is placed, 3 is a reaction chamber, 4 is a plasma generation chamber, 5 is a microwave transmitting window made of quartz or the like, 6
Is a microwave waveguide, and 7 is an optical fiber.

When ashing was performed using the downstream ashing apparatus shown in FIG. 4 under the following two-step ashing conditions, the resist applied to a 6-inch wafer at about 1.26 μm could be stripped in 60 seconds. .

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O gas downstream ashing process (corresponding to the first step of the conditions) was used, the same sample
Ashing in seconds.

Therefore, a stable process can be supplied by reducing the throughput by about 3%. Also, about
Ashing of 1000 6-inch wafers was performed.
The ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Ashing time: 54 seconds Second step (ashing rate: about 1.0 μm / min) O ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C Gas flow rate: O ₂ gas 1000 cc / min Ashing time : 6 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Ashing time: 60 seconds (Second embodiment) As in the first embodiment, the ashing process was performed using the downstream ashing apparatus shown in FIG. 4 under the following two-step ashing conditions. The resist applied to the wafer at about 1.26 μm can be stripped in 76 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O gas downstream ashing process (corresponding to the first step of the following conditions) is used, the same sample can be ashed in 76 seconds.

Therefore, a stable process can be supplied without any reduction in throughput. The ashing process was performed on about 1000 6-inch wafers, but the ashing rate did not become unstable.

Conditions First step O ₂ + H ₂ O gas downstream ashing (ashing rate about 1.0 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Ashing time: 70 seconds Second step (ashing rate about 1.0 μm / min) O ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C Gas flow rate: O ₂ gas 1000 cc / min Ashing time: 6 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate about 1.0 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Ashing time: 76 seconds (Third Embodiment) Similar to the first embodiment, when the ashing process was performed using the downstream ashing apparatus shown in FIG. 4 under the following two-step ashing conditions, the result was 6 inches. The resist applied to the wafer at about 1.26 μm can be removed in 47 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O + N ₂ gas downstream ashing process (corresponding to the first step of the following conditions) is used,
The same sample can be ashed in 43 seconds.

Therefore, a stable process can be supplied by reducing the throughput by about 8%. Also, about 1000
Ashing processing was performed on six 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: 800 cc / min of O ₂ gas H ₂ O gas 100 cc / min N ₂ gas 100 cc / min Ashing time: 37 seconds Second step (ashing rate: about 1.2 μm / min) O ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 1000 cc / min Ashing time: 10 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas Flow rate: O ₂ gas 800 / min H ₂ O gas 100 cc / min N ₂ gas 100 cc / min Ashing time: 44 seconds (Fourth embodiment) As in the first embodiment, shown in FIG. When ashing was performed using a downstream ashing apparatus under the following two-step ashing conditions, the resist applied to a 6-inch wafer at about 1.26 μm could be removed in 47 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O + N ₂ gas downstream ashing process (corresponding to the first step of the following conditions) is used,
The same sample can be ashed in 43 seconds.

Therefore, a stable process can be supplied by reducing the throughput by about 8%. Also, about 1000
Ashing processing was performed on six 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: 800 cc / min of O ₂ gas H ₂ O gas 150 cc / min N ₂ gas 50 cc / min Ashing time: 37 seconds Second step (ashing rate: about 1.3 μm / min) O ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 1000 cc / min Ashing time: 10 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 800 / min the H ₂ O gas 150 cc / min N ₂ gas 50 cc / min ashing time: 44 seconds (the fifth embodiment) as in the first embodiment, shown in FIG. 4 It was subjected to ashing treatment under the conditions of the two-step ashing shown in the following conditions using the down stream ashing apparatus, about 1.26μm coated resist a 6-inch wafer can be peeled off in 60 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O gas downstream ashing process (corresponding to the first step of the following conditions) is used, the same sample can be ashed in 60 seconds.

Therefore, a stable process can be supplied without any reduction in throughput. The ashing process was performed on about 1000 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 900 cc / min H ₂ O Gas 100 cc / min Ashing time: 54 seconds Second step (ashing rate: about 1.3 μm / min) O ₂ + N ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ Gas 1000 cc / min Ashing time: 6 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 900 / min the H ₂ O gas 100 cc / min ashing time: 60 seconds (sixth embodiment) as in the first embodiment, the downstream ashing apparatus shown in FIG. 4 It was subjected to ashing treatment under the conditions of the two-step ashing shown in the following conditions by using, approximately 1.26μm coated resist a 6-inch wafer can be peeled off in 60 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O gas downstream ashing process (corresponding to the first step of the following conditions) is used, the same sample can be ashed in 60 seconds.

Therefore, a stable process can be supplied without any reduction in throughput. The ashing process was performed on about 1000 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 900 cc / min H ₂ O Gas 100 cc / min Ashing time: 54 seconds Second step (ashing rate: about 1.3 μm / min) O ₂ + N ₂ O gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 900 cc / min N ₂ gas: 100 cc / min Ashing time: 6 seconds Conditions O ₂ + H ₂ O gas downstream ashing (ashing rate: about 1.3 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. gas flow rate: O ₂ gas 900 cc / min the H ₂ O gas 100 cc / min ashing time: 60 seconds (the seventh embodiment) as in the first embodiment, dounce shown in FIG. 4 Was subjected to ashing treatment under the conditions of the two-step ashing shown in following conditions using a stream ashing apparatus, it is possible to peel about 1.26μm coated resist a 6-inch wafer 46 seconds.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O + N ₂ gas downstream ashing process (corresponding to the first step under the following conditions) is used, the same sample can be ashed in 44 seconds.

Therefore, a stable process can be supplied by reducing the throughput by about 4%. Also, about 1000
Ashing processing was performed on six 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: 800 cc / min of O ₂ gas H ₂ O gas 100 cc / min N ₂ gas 100 cc / min Ashing time: 40 seconds Second step (ashing rate: about 1.3 μm / min) O ₂ + N ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C Gas flow rate: O ₂ gas 900 cc / min N ₂ gas 100 cc / min Ashing time: 6 seconds Conditions O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output : 1.5 kw stage temperature: 160 ° C. gas flow rate: O ₂ gas 800 / min the H ₂ O gas 100 cc / min N ₂ gas 100 cc / min ashing time: 44 seconds (example eighth) first In the same manner as in Example 1, when ashing was performed using the downstream ashing apparatus shown in FIG. 4 under the conditions of two-step ashing shown below, the resist applied to a 6-inch wafer at about 1.26 μm was removed in 46 seconds. be able to.

On the other hand, under the conditions shown below, O ₂ + H ₂
When only the O + N ₂ gas downstream ashing process (corresponding to the first step under the following conditions) is used, the same sample can be ashed in 44 seconds.

Therefore, a stable process can be supplied by reducing the throughput by about 4%. Also, about 1000
Ashing processing was performed on six 6-inch wafers, but the ashing rate did not become unstable. Conditions First step O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: 800 cc / min of O ₂ gas H ₂ O gas 100 cc / min N ₂ gas 100 cc / min Ashing time: 40 seconds Second step (ashing rate: about 1.3 μm / min) O ₂ + N ₂ gas downstream ashing Pressure: 0.8 Torr Microwave output: 1.5 kw Stage temperature: 160 ° C. Gas flow rate: O ₂ gas 900 cc / min N ₂ O gas: 100 cc / min Ashing time: 6 seconds Conditions O ₂ + H ₂ O + N ₂ gas downstream ashing (ashing rate: about 1.7 μm / min) Pressure: 0.8 Torr Micro wave output: 1.5 kw stage temperature: 160 ° C. gas flow rate: O ₂ gas 800 / min the H ₂ O gas 100 cc / min N ₂ gas 100 cc / min ashing time: 44 seconds

[0046]

According to the present invention, the H ₂ O component adhering to the wall of the vacuum chamber surrounding the plasma generation region can be removed without lowering the operation rate and throughput of the apparatus, and a stable ashing rate can be achieved. Is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an emission spectrum when O ₂ + H ₂ O gas downstream ashing in a first step of the present invention is performed.

FIG. 2 is a diagram showing an emission spectrum when O ₂ gas downstream ashing of the present invention is performed.

FIG. 3 is a diagram showing an emission spectrum immediately before the end of O ₂ gas downstream ashing of the present invention.

FIG. 4 is a schematic diagram showing a downstream ashing device used in the present invention.

FIG. 5 is a diagram showing an ashing rate with respect to H ₂ O / (O ₂ + H ₂ O)%.

FIG. 6: H ₂ O / (O ₂ + H ₂ O)% = 10% and ashing rate as set in FIG. 5 (1.3 μm)
/ Min) is a diagram showing an emission spectrum from plasma when (/ min) is obtained.

FIG. 7 shows that although the setting of H ₂ O / (O ₂ + H ₂ O)% = 10%, the set value of the ashing rate cannot be controlled and is set to a value 20% lower than the set value (1.0 μm / FIG. 7 is a diagram showing an emission spectrum when the value is (minute).

FIG. 8 is a graph showing an ashing rate (1.0 μm) according to FIG. 5 by setting H ₂ O / (O ₂ + H ₂ O)% = 20%;
/ Min) is a diagram showing an emission spectrum from plasma when (/ min) is obtained.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 2 Stage 3 Reaction chamber 4 Plasma generation chamber 5 Microwave transmission window 6 Optical fiber

Continuation of the front page (56) References JP-A-2-77125 (JP, A) JP-A-1-302821 (JP, A) JP-A-1-169929 (JP, A) JP-A-64-48421 (JP) JP-A-4-144226 (JP, A) JP-A-3-54571 (JP, A) JP-A-3-110843 (JP, A) JP-A-4-127419 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/30

Claims (3)

(57) [Claims] In a method of manufacturing a semiconductor device having a step of ashing a resist, the resist is ashed with a process gas containing at least a mixed gas of an O ₂ gas and a H ₂ O gas, and then the resist is further processed. A method of manufacturing a semiconductor device, comprising a step of performing an ashing process with a process gas containing at least no H ₂ O gas. 2. The process gas containing the mixed gas is O
₂ gas, mixed gas of H ₂ O gas and N ₂ gas or O ₂ gas
_{2. The} method for manufacturing a semiconductor device according to claim 1, wherein the gas is a mixed gas of gas, H ₂ O gas and N ₂ O gas. Wherein the H ₂ mixed gas or O of O gas contains no process gas is O ₂ gas and N ₂ gas ₂ gas and N ₂
2. The method for manufacturing a semiconductor device according to claim 1, wherein the mixed gas is a mixed gas of O gas.