JP2002270588A - Etching device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etching device and its method in which uniform etching machinability can be attained even when a plurality of substrates having different machining patterns are etched continuously while taking account of the instability of the etching system. SOLUTION: The etching device comprises an etching chamber 11 for etching an object M in gas phase under predetermined etching conditions, means 20 for observing the progressing conditions of etching of the object M, and means 40 for calculating the etching distribution of the object M based on the observation results of the observing means 20 and setting etching conditions based on the etching distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an etching apparatus and an etching method used in a manufacturing process of, for example, a photomask, a semiconductor wafer, and the like.

[0002]

2. Description of the Related Art In a method of manufacturing a semiconductor device, a dry etching technique is widely used as a fine processing means, and in recent years, it has been required to obtain a highly uniform processing accuracy in a surface of a substrate to be etched. .

In the above-described semiconductor device manufacturing process,
For example, a pattern is transferred to a resist by photolithography, and pattern processing is performed through the resist by, for example, dry etching such as reactive ion etching (RIE) or plasma etching.

[0004] By the above photolithography technology,
Similarly, a photomask pattern serving as a master for transferring a pattern to a resist is also manufactured by photolithography.

FIG. 7 shows a schematic configuration diagram of a dry etching apparatus as an example of a conventional etching apparatus.

[0006] As shown in FIG.
Is a processing chamber 110, an electrode 120 installed in the processing chamber 110 and capable of holding the object M, and an etching gas supply unit 1 for supplying a predetermined etching gas into the processing chamber 110.
30 and a gas exhaust unit 1 for exhausting gas in the processing chamber 110
40 and the electromagnetic coil 1 provided around the processing chamber 110.
50 and RF coil 160, electrode 120 and RF
A high-frequency power supply 170 for applying a high-frequency voltage to the coil 160, a photodetector 200, an end point determination unit 210, and a device control unit 220 are provided.

In the etching apparatus 100 shown in FIG. 7, an etching gas is supplied from an etching gas supply unit 130 into a processing chamber 110, and a high-frequency power supply
When a high-frequency voltage is applied to the RF coil 160 by 0, plasma P is generated, and the distribution shape of the generated plasma P is controlled by a magnetic field formed by a current flowing through the electromagnetic coil 150.

While controlling the plasma energy, the plasma P is drawn into the lower part of the processing chamber 110 by the high frequency voltage applied to the electrode 120, and
Etching of the substrate to be processed M placed on the substrate 0 is performed.

In the etching apparatus 100 shown in FIG. 7, as a mechanism for detecting that the etching of the material to be etched on the substrate to be processed M has progressed and has reached the lower layer, a photodetector 200 and an end point judging unit are provided. 210 are incorporated.

That is, light generated as a reaction product by etching is detected by the photodetector 200, and the end point is detected by utilizing the difference in the amount of light emitted between the material to be etched and the substrate material underlying it.

FIG. 8 shows an example of the light emission intensity signal detected by the photodetector 200.

As shown in FIG. 8, the emission intensity signal S increases with time when the etching process is started, and during the etching, the emission intensity signal S is kept almost constant. Then, etching begins to decrease when the signal strength begins to exit (time T _11), the etching is terminated at time T _1. Generally defined as the etching end point the time T _1.
Here, time T ₁ after the emission intensity signal represents the intensity of emission from the underlying material to be etched.

An emission intensity signal S as shown in FIG. 8 is output from the photodetector 200, and is compared with a predetermined threshold value set in advance by an end point determining section 210, so that the emission intensity signal is converted to a predetermined threshold value. If it becomes smaller than the value,
It is detected that the progress of the etching has reached the lower layer of the material to be etched, and the device control unit 220 controls the end of the etching process. Specifically, after detecting the etching end point, usually, in order to increase the stability of the process, 50% to 10% of the etching time up to that point is used.
Since over-etching is performed over 0% of the time, the end point of the etching has been used to determine the start time of over-etching.

Here, particularly, in the case of performing an etching process for forming a predetermined pattern on a photomask, substrates to be processed having different processing patterns are successively etched to be used in different device processes. Photomasks must be formed continuously. Conventionally, common etching conditions have been used when successively etching substrates to be processed with different processing patterns, and only the over-etching time is controlled for each substrate by detecting the end point of the etching. Thus, the substrate to be processed having a different processing pattern and an opening area of the film to be etched is etched.

[0015]

However, in etching using a halogen gas containing chlorine (Cl ₂ ) or the like and a fluorine-based gas such as C _x F _y used in the manufacture of a photomask, etc. A phenomenon in which the etching characteristics such as the selectivity of the resist and the etching rate change depending on the opening area of the film becomes remarkable.

The above-mentioned phenomenon is generally known as a loading effect. The influence on the etching distribution is described in, for example, “A Multiparameter Uniformity Stability”.
udyUtilizing Ptterns of Various Cr Loads (Proc.SPIE
3748,153 (1999)) ".

Therefore, as described above, in the method of controlling only the over-etching time for each substrate to be processed using the same etching conditions for all the substrates to be processed, if the etching process is performed continuously, Since the optimum etching conditions are different for each processing substrate, there is a problem that the required dimensional accuracy for the processing pattern of the photomask cannot be obtained.

Japanese Patent Application Laid-Open No. Hei 8-288258 discloses a technique in which information on a substrate to be processed is input in advance and etching is performed under the optimum etching conditions corresponding to the information. For some reason, for example, when fluctuations in pressure, etching gas supply amount, and the like occur on the apparatus side, there is a problem that the fluctuation amount cannot be fed back.

The present invention has been made in view of such circumstances, and has as its object to continuously etch a plurality of substrates to be processed having different processing patterns while considering the instability of the etching apparatus. Another object of the present invention is to provide an etching apparatus and an etching method capable of obtaining uniform etching processability.

[0020]

In order to achieve the above object, an etching apparatus according to the present invention comprises: an etching chamber for etching an object to be processed in a gas phase under predetermined etching conditions; Observation means for observing the progress of etching of the processing object, and etching processing condition setting for calculating an etching distribution in the processing object based on an observation result by the observation means and setting etching processing conditions based on the etching distribution. Means.

For example, the etching processing condition setting means may include an etching distribution calculating section for calculating an etching distribution in the object to be processed based on the observation result, and may be stored in advance based on the calculated etching distribution. An etching condition selection unit for selecting an etching condition corresponding to the etching distribution from the selected etching conditions.

Preferably, the etching processing condition setting means further includes an extraction unit for extracting, from the observation results, observation results corresponding to at least two positions on the object to be processed, and The calculation unit calculates the etching distribution based on the extracted observation result.

For example, the etching distribution calculating section detects an end point time of the etching processing of the object to be processed based on the observation result, and calculates the etching distribution based on the end point time.

Preferably, the observation means includes a light source for irradiating the object to be processed, which is installed in the etching processing chamber, and a reflected light of the light emitted from the light source from the object to be processed. A light-receiving unit that receives light and outputs a light-receiving signal corresponding to the amount of received light, wherein the etching processing condition setting means is configured to detect the light-receiving signal based on a temporal change in the light-receiving signal output from the light-receiving unit. Calculate the etching distribution in the object to be processed.

For example, the plasma processing apparatus has a plasma generating unit that generates plasma for performing an etching process on the object to be processed in the reaction chamber, and uses the light of the plasma in the processing chamber as the light source. Further, for example, an external light source is used as the light source.

According to the etching apparatus of the present invention described above,
The progress of etching of the object to be processed is observed by the observation means, the etching distribution in the object to be processed is calculated based on the observation result by the etching processing condition setting means, and the etching processing conditions based on the etching distribution are set. You. Thus, during the etching process, the etching process conditions can be changed according to the etching distribution so that the etching distribution can be made uniform.

Further, in order to achieve the above object, an etching method according to the present invention comprises the steps of: etching an object to be processed in a vapor phase under a first etching condition; Observing the progress, calculating the etching distribution in the object to be processed based on the observation result, setting a second etching process condition based on the etching distribution, Performing an etching process according to the etching process conditions.

For example, in the step of setting the second etching processing condition, an etching processing condition corresponding to the etching distribution is selected from the etching processing conditions stored in advance based on the etching distribution.

Preferably, in the step of calculating the etching distribution, the etching distribution is calculated based on observation results corresponding to at least two positions on the object to be processed among the observation results.

For example, in the step of calculating the etching distribution, an end point time of the etching process of the object to be processed is detected based on the observation result, and the etching distribution is calculated based on the end point time.

Preferably, in the step of observing the progress of etching of the object to be processed, the object to be processed is irradiated with light, and the light reflected by the object to be processed is detected. In the step of calculating the distribution,
An etching distribution in the object to be processed is calculated based on a temporal change of the detected light.

For example, in the step of detecting the light,
The reflected light from the material to be etched on the object to be processed is detected. Alternatively, for example, in the step of detecting the light, interference light between reflected light from the material to be etched on the object to be processed and light reflected from a lower layer of the material to be etched is detected.

According to the above etching method of the present invention,
The object to be processed is etched in the gas phase under the first etching condition, the progress of etching of the object to be processed is observed during the etching process, and the object to be processed is determined based on the observation result. Is calculated based on the etching rate distribution.
Is set, and the etching process is performed under the second etching condition. Thereby, during the etching process, according to the etching rate distribution,
The etching process can be performed by setting the second etching process condition so as to make the etching rate distribution uniform.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an etching apparatus and an etching method according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a schematic configuration diagram of an etching apparatus according to this embodiment. The etching apparatus shown in FIG. 1 is a magnetic neutral discharge (NLD) type plasma dry etching apparatus.

As shown in FIG. 1, the etching apparatus 1
Broadly speaking, an etching unit 10, a photodetector 20,
An input unit 30, an etching processing condition setting unit 40, and a device control unit 50 are provided.

The etching section 10 has a processing chamber 11 made of quartz or the like, and an electrode 12 capable of holding a substrate M to be processed is provided in the processing chamber 11.

An etching gas supply unit 13 for supplying a predetermined etching gas is provided above the processing chamber 11, and a gas exhaust for exhausting a gas such as an etching gas inside the processing chamber 11 is provided below the processing chamber 11. A part 14 is provided.

An electromagnetic coil 1 is provided around the processing chamber 11 for controlling the magnetic field intensity distribution in the processing chamber 11 by receiving power supply.
5 and RF coil 16 for generating plasma P
Are installed so as to orbit, and the electrode 12 and the RF
High frequency power supply 1 for applying high frequency voltage to coil 16
7 are provided respectively. This high frequency power supply 17
For example, it generates a high frequency of 13.56 MHz and is connected to the electrode 12 and the RF coil 16 via a matching box or the like (not shown).

A viewing window 18 is provided above the processing chamber 11, and a photodetector 20 is provided outside the viewing window 18.

The photodetector 20 detects light reflected from the substrate M by plasma light or light from an external light source.
It monitors the progress of etching of the substrate to be processed M, and it is preferable that monitoring can be performed at a plurality of points simultaneously over the entire region of the substrate to be processed M. For example, it is constituted by a CCD camera. With commonly available CCD cameras,
Since information corresponding to the number of pixels can be obtained, a CCD camera is installed at a position where a desired etching area of the target substrate M is reflected, and plasma light or reflected light from the target substrate M is detected using an external light source. Signals from a plurality of locations on the substrate to be processed M are taken in as detection signals. The progress of the etching on the substrate to be processed M is detected based on the temporal change of this signal.

The configuration of the photodetector 20 may be, for example, a plurality of laser beams and a number of photodetectors corresponding to the plurality of laser beams. Photodetector and viewing window 18 depending on the type of plasma
A monochromatic filter may be inserted between them. In this embodiment, the reason that the light emission when the material to be etched is not monitored is that only the light emission intensity signal of the entire substrate to be processed is obtained when the light emission is monitored. This is because the emission intensity signal at each monitor point on the substrate cannot be obtained.

The input unit 30 is provided for setting an observation point in the plane of the substrate M to be processed. More specifically, the input unit 30 is provided with the material of the processing target substrate M and the processing target substrate M
And a memory for storing an etching pattern to be formed in the memory, and an area for inputting substrate coordinates for monitoring a detection signal. Thus, by specifying and inputting the monitoring location of the etching progress based on the information of the substrate M read from the memory in advance, a desired plurality of substrates, that is, a plurality of substrates having different processing patterns can be provided. It is possible to accurately observe the progress of etching at the coordinates of.

The etching processing condition setting unit 40 includes a signal extraction unit 41, a speed distribution calculation unit 42, and a distribution amount calculation unit 43.
And a processing condition storage unit 44 and a processing condition selection unit 45.

The signal extracting section 41 receives a light receiving signal (reflected light intensity signal) from the photodetector 20 over the entire substrate to be processed and a signal from the input section 30 which designates a monitoring position of the etching progress. The input unit 30 extracts and outputs only the reflected light intensity signal at the designated substrate coordinates from the input unit 30. If the reflected light intensity signal from the photodetector 20 contains noise or the like, filtering or the like is also performed.

The speed distribution calculating section 22 calculates an etching speed distribution for each substrate coordinate from the reflected light intensity signal extracted from the signal extracting section 41, and outputs a signal corresponding to the calculated etching speed distribution.

FIG. 2 shows a temporal change of the reflected light intensity signals S ₁ and S ₂ input to the velocity distribution calculating section 22 when two different points on the substrate are monitored. The reflected light intensity signals S ₁ and S ₂ shown in FIG. 2 are obtained by etching a metal film deposited on a quartz glass substrate.

As shown in FIG. 2, when the reflected light from the substrate M is monitored, the reflected light intensity signals S ₁ , S ₂
Increases over time when the etching process is started,
During the etching, the reflected light intensity signals S ₁ and S ₂ are kept substantially constant.

[0049] Then, the reflected light intensity signal S _1, S _2, a metal film made of a material to be etched with the progress of etching becomes thin, the reflected light intensity signal S by the optical density is reduced
₁ and S ₂ decrease. After the metal film is completely etched, the reflected light intensity signals S ₁ and S ₂ saturate at the value of the reflectance of the glass substrate under the metal film.
By monitoring the temporal change in the reflected light intensity signals S _1, S _2, it is possible to detect the etching end point time T _1, T _2, the etching end point time between different monitors points on the substrate T _1, T ₂ Can be calculated, the etching time in the substrate surface, that is, the etching rate distribution can be calculated.

More specifically, the speed distribution calculating section 42 calculates a predetermined threshold value and a reflected light intensity signal S
_1, compared with the S _2, when the reflected light intensity signal S _1, S ₂ is smaller than a predetermined threshold value, to detect the etching end point time T _1, T _2. Then, the end point time for each substrate coordinate is stored in a memory (not shown), and the last end point time T _{e at} the monitor location (in this case, T ₂ ).
Is detected, the etching rate distribution for each substrate coordinate is calculated, and a signal corresponding to the calculated etching rate distribution is output to the distribution amount calculation unit 43.

In actually calculating the etching rate distribution, at least two monitor points are required, and it is desirable to take more monitor points for accurate detection. For example, the in-plane distribution of the etching rate can be detected with high accuracy by arranging the monitor point coordinates in a ring on a lattice or concentric circles.

The distribution amount calculating section 43 has a program for calculating an etching distribution amount indicating the progress of etching in the surface of the substrate to be processed, from a signal indicating the etching speed at each monitor point coordinate of the substrate M to be processed. Then, a signal indicating an etching rate at each monitor point coordinate of the substrate M to be processed is input from the speed distribution calculating unit 42, an etching distribution amount is calculated, and a signal indicating the etching distribution amount is output. Here, the etching distribution amount includes, for example, information on the tendency of the distribution in which the etching rate is high in a specific region such as the periphery or the center of the substrate to be processed, and the degree of the tendency.

The processing condition storage unit 44 previously stores, for each etching distribution amount, a data table in which etching conditions for canceling the distribution tendency and the degree thereof to make the etching rate distribution uniform are defined. I have. The etching conditions include a bias and an RF voltage applied to the electrode 12 and the RF coil 16 of the etching processing unit 10, a coil current flowing through each of the electromagnetic coils 15, a degree of vacuum in the processing chamber 11 by the gas exhaust unit 14, There are a gas flow rate supplied by the etching gas supply unit 13, a gas component ratio, an etching time, and the like.

The processing condition selecting section 45 includes a distribution amount calculating section 43
, A signal indicating the etching distribution amount is input, the etching condition corresponding to the etching distribution amount is read out from the processing condition storage unit 44, an appropriate over-etching condition is selected, and a signal corresponding to the over-etching condition is output. .

The apparatus control section 50 receives a signal indicating an over-etching condition from the processing condition selecting section 45, and performs processing in the etching processing section 10 based on the over-etching condition and at a preset timing. Give feedback to.

Next, an etching process using the above etching apparatus 1 will be described with reference to a flowchart shown in FIG. As an example, a case where the number of monitor points is two will be described.

First, when the substrate M to be processed is set on the electrode 12 in the processing chamber 11, the etching reaction gas is supplied into the processing chamber 11 by the gas supply unit 13, and the RF coil 16 is Is applied with a high-frequency voltage to generate a plasma P, and the distribution shape of the generated plasma P is controlled by a magnetic field formed by flowing a current through the electromagnetic coil 15.

Then, as shown in step ST 1, while controlling the generated plasma energy, the plasma P is drawn into the lower part of the processing chamber 11 by the high frequency voltage applied to the electrode 12 by the high frequency power supply 17, 1
Etching of the substrate to be processed M placed on 2 is performed.

During the above-described etching process, the light of the plasma used for the etching process is reflected by the substrate M to be processed, and the photodetector 20 reduces the amount of light reflected (received) from the entire region of the substrate M to be processed. A corresponding reflected light intensity signal is generated and output to the signal extraction unit 41.

The reflected light intensity signal from the entire substrate to be processed is
When input to the signal extraction unit 41, only the reflected light intensity signals S ₁ and S _{2 at the} specified substrate coordinates are based on a signal input in advance from the input unit 30 and specifying a monitoring location of the etching progress. Extracted and velocity distribution calculator 4
2 is output.

When the extracted reflected light intensity signals S ₁ and S ₂ are input to the velocity distribution calculating section 42, the reflected light intensity signals S ₁ and S ₂ are compared with a predetermined threshold value set in advance. You. When the reflected light intensity signals S ₁ is smaller than a predetermined threshold, is detected etching end point time T _1, the etching end point time T ₁ is stored for each board coordinates in a memory (not shown) . Similarly, when the end point time T _{2 of the} reflected light intensity signal S ₂ is detected, and the last end point time T _e (in this case, T ₂ ) at the monitor location is detected, each of the substrate coordinates is determined. The etching rate distribution is calculated, and a signal corresponding to the calculated etching rate distribution is output to distribution amount calculating section 43 (step ST2).

When a signal based on the etching rate distribution is input to the distribution amount calculator 43, an etching distribution amount indicating the progress of the etching in the surface of the substrate to be processed is calculated based on its tendency and degree, and the etching distribution amount is calculated. Is output to the processing condition selection unit 45 (step ST3).

When a signal based on the etching distribution amount is input to the processing condition selection unit 45, the etching processing condition corresponding to the etching distribution amount is read from the processing condition storage unit 44, and a signal indicating the etching processing condition is output. Is output to the device control unit 50 (step ST4).

When a signal indicating the etching processing condition is input to the apparatus control unit 50, the processing in the etching processing unit 10 is fed back based on a predetermined timing based on the etching processing condition. Then, overetching is performed by the etching processing unit 10 under the etching processing conditions (step ST5).

In the etching apparatus and the etching method according to the present embodiment, the progress of the etching is monitored from the end point of each monitor point of the substrate M, and the progress of the etching varies in the surface of the substrate to be processed. However, since the over-etching process is performed by setting the over-etching condition so as to cancel out the variation and make the etching distribution uniform, the dimensional accuracy of the processed pattern can be improved. Further, in the present embodiment, a new etching condition is set by calculating the etching distribution amount indicating the progress of etching in the substrate plane from the coordinates of each monitor point of the substrate and the signal indicating the corresponding etching speed, and Since the selection is performed only by selecting from the prepared data table, the data structure for setting new etching conditions can be simplified.

Second Embodiment In the first embodiment, for example, an example in which the reflected light from the target substrate M is monitored has been described.
An example of monitoring interference light from a substrate to be processed will be described.

In the etching apparatus according to the present embodiment, the substrate to be processed M ′ having a material which is difficult to monitor the reflected light, for example, a transparent material to be etched such as silicon oxide or resist resin is processed. It is effective in the case. That is, when the material to be etched is made of a material having transparency, the interference light between the reflected light of the plasma light used for the etching process from the material to be etched and the reflected light from the lower layer material of the material to be etched is used. Will be observed.

FIG. 4 is a schematic configuration diagram of a dry etching apparatus according to the present embodiment. The basic configuration of the etching apparatus 1 ′ shown in FIG. 4 is the same as that of the above-described first embodiment, but the functions of the input unit 30 ′ and the speed distribution calculation unit 42 ′ are different. Hereinafter, only portions different from the first embodiment will be described for simplification of the description.

The input section 30 ′ is used to specify the monitoring position of the etching progress as described in the first embodiment, and to change the process condition from the etching progress in the plane of the substrate M to be processed. (Processing condition change time) T ₀ can be specified, and a signal corresponding to the specified monitor location and a signal corresponding to the specified processing condition change time T ₀ are output.

The speed distribution calculating section 42 ′ includes a signal extracting section 41.
Input the received light signal (interference light intensity signal) extracted from
In addition, a signal corresponding to the processing condition change time T ₀ is input from the input unit 30 ′, an etching rate distribution for each substrate coordinate is calculated, and a signal corresponding to the calculated etching rate distribution is output.

FIG. 5 shows a temporal change of the interference light intensity signals S ₁ ′ and S ₂ ′ input to the velocity distribution calculation unit 22 when two different points on the substrate are monitored. The interference light intensity signals S ₁ ′ and S ₂ ′ shown in FIG.
Is obtained when a substrate to be processed M ′ in which polysilicon is formed on a silicon substrate is etched.

As shown in FIG. 5, when the interference light from the substrate to be processed M ′ is monitored, the interference light intensity signal S ₁ ′,
When the etching process is started, S ₂ ′ changes periodically with time according to the film thickness of the material to be etched.

Therefore, when monitoring the interference light, unlike the case of monitoring the reflected light, it is possible to detect the progress of the etching in the plane of the substrate to be processed M ′ during the etching.

Specifically, for example, the processing condition change time T
_When detecting the etching rate distribution at _0, the number of peaks and valleys of the interference light intensity signals S ₁ ′ and S ₂ ′ is counted, and the etching rate distribution in the surface of the substrate to be processed can be calculated.

As a method of detecting the end point when monitoring the interference light intensity signals S ₁ ′ and S ₂ ′, unlike the case of monitoring the reflected light, the etching is performed in advance based on the film thickness of the material to be processed. Is set based on the number of peaks and valleys of the interference light. Then, the interference light intensity signal S
_When the peaks and valleys of ₁ ′ and S ₂ ′ reach the count number set as the end point in advance, the etching end point time T ₁ ′,
T ₂ ′ can be detected, and the end time T ₁ ′, T ₂ ′ for each detected substrate coordinate is stored in a memory (not shown). Then, similarly to the first embodiment, when the last end point time T _e ′ (T ₂ ′ in this case) at the monitoring location is detected, the etching end point times T ₁ ′, T ₂ between different points on the substrate are detected. By comparing ', the etching rate distribution for each substrate coordinate is calculated, and a signal corresponding to the calculated etching rate distribution is output to the distribution amount calculating unit 43.

Next, the operation of the etching process using the above etching apparatus 1 'will be described with reference to the flowchart shown in FIG. As an example, a case where the number of monitor points is two will be described.

First, the monitor 30 in the plane of the substrate M to be processed and the time T _{0 at} which process conditions are changed based on the progress of etching are input from the input unit 30 ′ (step ST 11).

Then, similarly to the first embodiment, the target substrate M 'is etched under predetermined etching processing conditions (step ST12).

Then, during the etching process,
The interference light from the substrate to be processed M ′ is detected by the photodetector 20, and an interference light intensity signal corresponding to the amount of interference (the amount of received light) from the entire region of the substrate to be processed M ′ is output to the signal extraction unit 41. .

The interference light intensity signal from the entire substrate to be processed is
When input to the signal extraction unit 41, the interference light intensity signals S ₁ ′ and S _{2 at the} designated substrate coordinates are preliminarily input from the input unit 30 ′ based on a signal designating a monitoring location of the etching progress. Is extracted and output to the velocity distribution calculation unit 42 '.

Then, the extracted interference light intensity signal S
_{When 1} ′ and S ₂ ′ are input to the speed distribution calculation unit 42 ′,
Whether previously inputted process condition changes timing T ₀ has elapsed or not (step ST13).

When the processing condition change time T ₀ has been reached,
', The interference light intensity signals S ₁ at the time of processing condition change timing T _0' velocity distribution calculating unit 42, are mountains and numbers counted valley S ₂ ', the etching rate distribution in the target substrate plane The distribution amount calculation unit 43 calculates the etching distribution amount indicating the etching rate distribution in the surface of the substrate to be processed by its tendency and degree (step S).
T14). Subsequently, the etching condition corresponding to the etching distribution amount is read out from the processing condition storage unit 44 by the processing condition selection unit 45 and output to the device control unit 45 (step ST15). Based on the etching processing conditions, the processing in the etching processing unit 10 is fed back, and etching is performed under the etching processing conditions (step ST).
16).

Before reaching the processing condition change time T ₀ , if the speed distribution calculation unit 42 ′ detects the last end time T _e ′ (T ₂ ′ in this case) at the monitor location, (Step ST17), the etching rate distribution is calculated from the etching end point times T ₁ ′, T ₂ ′ for each of the monitor points, and the distribution amount calculating unit 43 determines the etching rate distribution in the surface of the substrate to be processed according to its tendency and degree. Is calculated (step ST)
18). Then, the processing condition selection unit 45 reads out the etching processing condition corresponding to the etching distribution amount from the processing condition storage unit 44 and outputs it to the device control unit 50 (step ST19). Based on the etching processing conditions, feedback is given to the processing in the etching processing unit 10, and over-etching is performed under the etching processing conditions (step ST20).

In the etching apparatus and the etching method according to the present embodiment, in addition to the effects of the first embodiment, the progress of the etching can be grasped by monitoring the interference light from the target substrate M even during the etching. Therefore, it is possible to set new etching processing conditions that make the etching rate distribution uniform, and it is possible to further improve the dimensional accuracy of the processing pattern.

The etching apparatus of the present invention is not limited to the above embodiment. For example, in the present embodiment, N
Although an LD type plasma dry etching apparatus has been described as an example, the present invention is not limited to this. For example, other forms of plasma dry etching such as a parallel plate type plasma etching apparatus, a magnetic field microwave plasma etching apparatus, and an ECR plasma etching apparatus may be used. The present invention can be applied to an etching apparatus or a dry etching apparatus that does not use plasma as a light source for monitoring. Note that in the case of a dry etching apparatus that does not use plasma as a monitoring light source, external light may be used to observe the progress of etching of a substrate to be processed. In addition, various changes can be made without departing from the spirit of the present invention.

[0086]

According to the present invention, uniform etching processability can be obtained even when processing a plurality of workpieces having different processing patterns.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a dry etching apparatus according to a first embodiment.

FIG. 2 shows a case where two different points on a substrate are monitored.
It shows a temporal change of a reflected light intensity signal.

FIG. 3 is a flowchart for explaining an etching process using the etching apparatus according to the first embodiment.

FIG. 4 is a schematic configuration diagram of a dry etching apparatus according to a second embodiment.

FIG. 5 shows a case where two different points on a substrate are monitored.
5 shows a temporal change of the interference light intensity signal.

FIG. 6 is a flowchart for explaining an etching process using the etching apparatus according to the second embodiment.

FIG. 7 is a schematic configuration diagram of a dry etching apparatus according to a conventional example.

FIG. 8 illustrates an example of a light emission intensity signal when light from a substrate to be processed is monitored.

[Explanation of symbols]

1, 1 ': etching apparatus, 10: etching processing unit,
11 processing chamber, 12 electrodes, 13 etching gas supply unit, 14 gas exhaust unit, 15 electromagnetic coil, 16 RF
Coil, 17 high-frequency power supply, 18 viewing window, 20 photodetector, 30 and 30 'input unit, 40 etching processing condition setting unit, 41 signal extraction unit, 42 and 42' speed distribution calculation unit, 43: distribution amount calculation unit, 44: processing condition storage unit,
45: processing condition selection unit, 50: device control unit, M, M '...
Substrate to be processed, 100: etching apparatus (conventional example), 11
0: processing chamber, 120: electrode, 130: etching gas supply unit, 140: gas exhaust unit, 150: electromagnetic coil, 16
0: RF coil, 170: high frequency power supply, 200: photodetector, 210: end point determination unit, 220: device control unit.

Claims (14)

[Claims] 1. An etching chamber for etching an object to be processed in a vapor phase under predetermined etching conditions, an observation unit for observing the progress of etching of the object to be processed, and an observation by the observation unit. An etching apparatus that calculates an etching distribution in the object to be processed based on a result and sets etching processing conditions based on the etching distribution. 2. An etching processing condition setting unit, comprising: an etching distribution calculating unit configured to calculate an etching distribution in the object to be processed based on the observation result; and an etching distribution calculating unit configured to store the etching distribution in advance based on the calculated etching distribution. The etching apparatus according to claim 1, further comprising: an etching condition selecting unit that selects an etching condition corresponding to the etching distribution from the etching conditions. 3. The etching distribution calculation unit further comprises: an extraction unit for extracting, from the observation results, observation results corresponding to at least two positions on the object to be processed. 3. The etching apparatus according to claim 2, wherein the etching apparatus calculates the etching distribution based on the extracted observation result. 4. The etching distribution calculating unit according to claim 2, wherein the etching distribution calculating unit detects an end point time of the etching processing of the object to be processed based on the observation result, and calculates the etching distribution based on the end point time. Etching equipment. 5. An observing means, comprising: a light source for irradiating an object to be processed set in the etching processing chamber; and a light reflected from the object to be processed irradiated by the light source. A light-receiving unit that outputs a light-receiving signal according to the amount of received light, wherein the etching processing condition setting unit is configured to set the processing target object based on a temporal change in the light-receiving signal output from the light-receiving unit 2. The etching apparatus according to claim 1, wherein an etching distribution in the object is calculated. 6. The etching apparatus according to claim 5, further comprising: a plasma generation unit configured to generate plasma for performing an etching process on the object to be processed in the reaction chamber, and using the light of the plasma in the processing chamber as the light source. . 7. The etching apparatus according to claim 5, wherein said light source is an external light source. 8. A step of etching the object to be processed in a vapor phase under a first etching condition; a step of observing the progress of etching of the object to be processed; An etching method, comprising: calculating an etching distribution in the object to be processed; setting a second etching processing condition based on the etching distribution; and performing an etching process under the second etching processing condition. 9. In the step of setting the second etching processing condition, an etching processing condition corresponding to the etching distribution is selected from the etching processing conditions stored in advance based on the etching distribution. 8
The described etching method. 10. The etching distribution according to claim 8, wherein in the step of calculating the etching distribution, the etching distribution is calculated based on observation results corresponding to at least two positions on the object to be processed among the observation results. Etching method. 11. The step of calculating the etching distribution detects an end point time of an etching process of the object to be processed based on the observation result, and calculates the etching distribution based on the end point time. The described etching method. 12. In the step of observing the progress of etching of the object to be processed, the object to be processed is irradiated with light, light reflected by the object to be processed is detected, and the etching distribution is determined. 9. The etching method according to claim 8, wherein, in the calculating step, an etching distribution in the object to be processed is calculated based on a temporal change of the detected light. 13. The etching method according to claim 12, wherein in the step of detecting the light, reflected light from the material to be etched on the object to be processed is detected. 14. The method according to claim 12, wherein, in the step of detecting light, interference light between reflected light from the material to be etched on the object to be processed and light reflected from a lower layer of the material to be etched is detected. Etching method.