JPH065564A - Single wafer type dry etching device and single wafer type dry etching method using the device - Google Patents

Abstract

PURPOSE:To enable improvement of yield of dry etching treatment of a semiconductor wafer. CONSTITUTION:The device is provided with a treatment chamber 11 for dry- etching a semiconductor wafer, a dummy semiconductor wafer carrying-in/out means 3 for carrying in and out a dummy semiconductor wafer 7 to and from the treatment chamber 11 and a treatment semiconductor wafer carrying-in/out means 2 for carrying in and out a semiconductor wafer 6 for dry etching treatment to and from the treatment chamber 11. At first, the dummy semiconductor wafer 7 is carried in to the treatment chamber 11 by using the device and preliminary discharge is performed for a specified time. Then, a dummy semiconductor wafer is carried out, the treatment semiconductor wafer 6 is carried into the treatment chamber 11 one by one and etching treatment is performed. Thereby, all the semiconductor wafers 6 for dry etching treatment can be dry etched uniformly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-wafer dry etching apparatus and a dry etching method using the same, and more particularly to a single-wafer dry etching capable of improving the yield of processed semiconductor wafers after the dry etching processing. The present invention relates to an etching apparatus and a dry etching method using the apparatus.

[0002]

2. Description of the Related Art In the manufacture of LSIs, microfabrication centering on etching is extremely important in order to further increase the scale, density and speed. Etching technology is evolving with the devices created from time to time. In recent VLSI, dry etching is mainly used, and high precision processing of submicron level has become possible.

In the dry etching, the pattern of the photoresist film formed by the photolithography technique is used as a mask and the underlying material (SiO ₂ , Si ₃ N ₄ , polycrystalline S) is used.
i, Al, etc.) to form a pattern.

The structure of a typical dry etching apparatus is
As shown in FIG. 5, the processing part has a circular parallel plate electrode 10,
14 and the semiconductor wafer 6 is placed on one of the electrodes 10 in between. The inside of the processing chamber 11 is set to 1 by the rotary pump 16 and the mechanical booster pump 15.
While maintaining a vacuum of about 0 ^{-2 to 1} Pa, a high frequency voltage of several hundred V at 13.56 MHz is applied between the parallel plate electrodes 10 and 14 to form CF ₄ as an etchant.
(Carbon tetrafluoride) or the like is supplied, and this is plasmatized and then activated to etch, for example, polycrystalline silicon.

Next, as a conventional single wafer type dry etching apparatus, an RF (Radio Frequency) discharge type plasma etching apparatus will be described.

This plasma etching apparatus is used in a semiconductor device manufacturing process to remove an insulating film, a metal film, a semiconductor film and the like formed on a semiconductor wafer during the manufacturing process.

First, referring to FIG. 6, in this RF plasma etching apparatus, a processing semiconductor wafer chamber 2 for accommodating a semiconductor wafer before etching processing in a vacuum container 1 is provided.
And a transfer chamber 12 for moving the semiconductor wafer 6,
A discharge chamber 11 for performing an etching process is provided. In the processing semiconductor wafer chamber 2, a processing semiconductor wafer cassette 4 for accommodating the semiconductor wafer 6 before the etching processing and the semiconductor wafer 6 after the etching processing is installed. In this case, the processing semiconductor wafer cassette 4 that can accommodate, for example, 25 semiconductor wafers 6 is used. The processing semiconductor wafer chamber 2 and the transfer chamber 12 are provided adjacent to each other, and the processing semiconductor wafer chamber 2 and the transfer chamber 12 are partitioned by a gate valve 18.

A discharge chamber 11 is provided adjacent to the transfer chamber 12. A wafer carry-out / carry-in belt 8 for carrying the semiconductor wafer 6 into the discharge chamber 11 is provided in the carrying chamber 12.
Is provided. The semiconductor wafers 6 are carried into the discharge chamber 11 one by one by the wafer carry-out / carry-in belt 8. This wafer unloading / importing belt 8
A rotary arm 9 is provided at a predetermined position in the transfer chamber 12 in order to carry the semiconductor wafer 6 from the discharge chamber 11 into the discharge chamber 11. By this rotating arm 9, the semiconductor wafers 6 are carried into the discharge chamber 11 one by one.

In the discharge chamber 11, there is a stage (lower electrode).
10 and the upper electrode 14 are grounded. This stage 1
Referring to FIG. 7, an RF power source 13 for causing a discharge in the discharge chamber 11 is connected to 0. This stage 1
It is possible to perform plasma processing by disposing the semiconductor wafer 6 on the substrate 0 and applying an RF voltage to the stage (cathode electrode) 10.

Referring again to FIG. 6, the semiconductor wafer 6 which has been subjected to the plasma treatment in the discharge chamber 11 is carried by the rotating arm 9 to the wafer carrying-out / carrying belt 8.
It is stored in the processing semiconductor wafer cassette 4 again.

In order to perform the plasma processing using the RF plasma etching apparatus having the above structure, first, the semiconductor wafer 6 to be subjected to the plasma etching processing is carried into the processing semiconductor wafer chamber 2. At this time, the semiconductor wafers 6 are normally loaded into the processing semiconductor wafer chamber 2 while being stored in the cassette 4 in a set of 25 sheets. Next, the gate valve 18 is opened and the processing semiconductor wafer cassette 4 is opened.
The semiconductor wafers 6 therein are placed one by one on the wafer unloading / carrying belt 8. The semiconductor wafer 6 placed on the wafer unloading / carrying belt 8 in this manner is carried to the vicinity of the discharge chamber 11 by the wafer unloading / carrying belt 8.

Next, the discharge chamber 11 is rotated by the rotating arm 9.
The semiconductor wafer 6 will be mounted on the stage (cathode electrode) 10 inside. A predetermined etching gas is introduced into the discharge chamber 11 according to the material to be etched. After that, the RF voltage is applied to the stage (cathode electrode) 10 by the RF power source. As a result, plasma is generated in the discharge chamber 11 and the semiconductor wafer 6
Etch the desired film above.

After the etching process is completed, the semiconductor wafer 6 is placed on the wafer loading / unloading belt 8 by the rotating arm 9. Next, the semiconductor wafer 6 is stored in the cassette 4 placed in the processing semiconductor wafer chamber 2 again by the wafer unloading / carrying belt 8. In this case, all the etching processing of the 25 semiconductor wafers 6 is completed, and when the 25 semiconductor wafers 6 are stored in the processing semiconductor wafer cassette 4, the processing semiconductor wafer chamber 2 is processed. Semiconductor wafer cassette 4
At the same time, the semiconductor wafer 6 is taken out and sent to the next step.

[0014]

However, the above-mentioned dry etching apparatus has the following problems.

First, referring to FIG. 8, the vertical axis shows the temperature (° C.) of the upper electrode and the horizontal axis shows the time (seconds), and a graph when the semiconductor wafers are continuously etched by the dry etching apparatus is shown. is there. In the figure, t ₁ is a time for loading / unloading a semiconductor wafer, and t ₂ is a discharging time for one semiconductor wafer.

As can be seen from the figure, until the upper electrode temperature (saturation temperature T ° C.) for normally performing the desired etching on the semiconductor wafer is reached, the saturation temperature T ° C. must be reached unless approximately three semiconductor wafers are discharged. Does not reach For example, when dry etching is performed without reaching the saturation temperature T ° C. of the upper electrode, the etching characteristics are adversely affected as shown in FIGS. 9 and 10.

FIG. 9 is a graph showing the relationship between the number of processed semiconductor wafers and the in-plane uniformity of the etching rate. In the processing of the first to third semiconductor wafers, the etching is non-uniform. I understand.

FIG. 10 is a graph showing the relationship between the number of processed semiconductor wafers and the etching rate, and it can be seen that the etching amount is slow and not constant in the processing of the first to third semiconductor wafers. .

Therefore, during continuous dry etching of semiconductor wafers, the first to third semiconductor wafers cause etching defects, which hinders improvement in yield during dry etching of semiconductor wafers. Was there.

The present invention has been made to solve the above problems, and provides a single-wafer dry etching apparatus and a dry etching method using the same, which can improve the yield during the dry etching of semiconductor wafers. The purpose is to provide.

[0021]

In the single-wafer dry etching apparatus according to the first aspect of the present invention,
First, a processing chamber for performing a dry etching process on a semiconductor wafer, a dummy semiconductor wafer loading / unloading means for loading and unloading a dummy semiconductor wafer to and from the processing chamber, and a semiconductor for performing a dry etching process on the processing chamber. And a processing semiconductor wafer loading / unloading means for loading / unloading the wafer.

Next, in a dry etching method using a single wafer dry etching apparatus according to a second aspect of the present invention, first, a dummy semiconductor is provided in a processing chamber for performing a dry etching process on a semiconductor wafer. A wafer is loaded and preliminary discharge is performed for a predetermined time. The dummy wafer is carried out of the processing chamber. After the dummy semiconductor wafers are unloaded, the processing semiconductor wafers to be subjected to the etching process are loaded into the processing chamber one by one, the main discharge is performed, the dry etching is performed, and the processing semiconductor wafers are unloaded to the outside of the processing chamber. The semiconductor wafer is continuously manufactured.

[0023]

According to the single-wafer dry etching apparatus and the dry etching method using the apparatus according to the present invention, first, a dummy semiconductor wafer is carried into a processing chamber for preliminary discharge, and then dry etching processing is performed. The semiconductor wafer for performing the process is carried into the processing chamber and the main discharge is performed.

As a result, by performing the preliminary discharge using the dummy semiconductor wafer, the main discharge is performed on the semiconductor wafer while the upper electrode is set to the saturation temperature T ° C. in advance. It becomes possible to make all the etching characteristics uniform.

Further, by providing the dummy semiconductor wafer chamber and the processing semiconductor wafer chamber separately, all the semiconductor wafers loaded into the processing semiconductor wafer can be uniformly etched, so that the dry etching process is performed. It is possible to improve the yield and workability.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a single-wafer dry etching apparatus according to the present invention will be described below. As the single-wafer dry etching apparatus, an RF plasma etching apparatus will be described as a typical example of dry etching. Since the operation principle of this device is the same as that of the conventional technique, the description thereof is omitted here.

First, referring to FIG. 1, this RF plasma etching apparatus includes a processing semiconductor wafer chamber 2 for accommodating a processing semiconductor wafer 6 for performing an etching process in a vacuum chamber 1 and a dummy semiconductor wafer chamber 2. A dummy semiconductor wafer chamber 3 for housing the semiconductor wafer 7, a processing semiconductor wafer 6 and a transfer chamber 12 for moving the dummy semiconductor wafer, and a discharge chamber 11 for performing a dry etching process. There is. The processing semiconductor wafer chamber 2 has a processing semiconductor wafer 6 for performing an etching process.
A processing semiconductor wafer cassette 4 for accommodating the above is placed. In this embodiment, a processing semiconductor wafer cassette 4 capable of accommodating, for example, 25 processing semiconductor wafers 6 is used. Processing semiconductor wafer chamber 4
And the transfer chamber 12 are provided adjacent to each other, and the processing semiconductor wafer chamber 2 and the transfer chamber 12 are partitioned by a gate valve 18.

A dummy semiconductor wafer chamber 3 is provided near the processing semiconductor wafer chamber 2. In the dummy semiconductor wafer chamber 3, the dummy semiconductor wafer 7
A dummy semiconductor wafer cassette 5 for accommodating the above is placed. In this embodiment, a dummy semiconductor wafer cassette 5 that can store, for example, 25 dummy semiconductor wafers 7 is used. As a result, since one dummy semiconductor wafer cassette 7 is used each time the processing semiconductor wafer cassette 4 is replaced, the dummy semiconductor wafer cassette 5 is replaced by 1 each time 25 processing semiconductor wafer cassettes 4 are replaced. It will be exchanged twice, and it will be possible to greatly improve workability.

Next, the discharge chamber 6 is provided adjacent to the transfer chamber 12. A wafer carry-out / carry-in belt 8 for carrying the dummy semiconductor wafer 7 and the processing semiconductor wafer 6 into the discharge chamber 11 is provided in the carrying chamber 12. The dummy semiconductor wafer 7 and the processing semiconductor wafer 6 are carried into the discharge chamber 11 one by one by the wafer carry-out / carry-in belt 8. In order to carry the dummy semiconductor wafer 7 and the processing semiconductor wafer 6 into the discharge chamber 11 from the wafer carry-out / carry-in belt 8, a rotary arm 9 is provided at a predetermined position in the carrying chamber 12. By this rotating arm 9, the dummy semiconductor wafers 7 and the processing semiconductor wafers 6 are carried into the discharge chamber 11 one by one.

In the discharge chamber 11, a stage (lower electrode)
10 and an upper electrode (not shown) are mounted. An RF power source (not shown) for causing a discharge in the discharge chamber 11 is connected to the stage (lower electrode) 10. A dummy semiconductor wafer 7 or a processing semiconductor wafer 6 is placed on the stage (lower electrode) 10 and RF
By applying a power source to the stage (lower electrode) 10, plasma processing can be performed.

Next, a method of performing plasma etching using the RF plasma etching apparatus having the above structure will be described. First, the dummy semiconductor wafer 7 and the processing semiconductor wafer 6 are loaded into the processing semiconductor wafer chamber 2 and the dummy semiconductor wafer chamber 5, respectively. At this time, the processing semiconductor wafers 6 are normally loaded into the processing semiconductor wafer chamber 4 while being stored in the processing semiconductor wafer cassette 4 in a set of 25 sheets. On the other hand, the dummy semiconductor wafers 7 are also loaded into the dummy semiconductor wafer chamber 3 in a state where they are normally housed in a set of 25 semiconductor wafers for dummy 5 in the same manner. Next, the gate valve 18
Is opened, and one dummy semiconductor wafer 7 in the dummy semiconductor wafer cassette 5 is transferred onto one wafer unloading / importing belt 8. The dummy semiconductor wafer 7 thus transferred to the wafer unloading / importing belt is
It is carried to the vicinity of the discharge chamber 6 by the carry-in belt 8.

Next, the discharge chamber 11 is rotated by the rotating arm 9.
The dummy semiconductor wafer 7 is transferred onto the stage (lower electrode) 10 inside. After that, the RF power source applies the RF power source to the stage (lower electrode) 10. As a result, plasma is generated in the discharge chamber 11. By performing this for a predetermined time, preliminary discharge is performed until the temperature of the upper electrode in the discharge chamber 11 reaches the saturation temperature T ° C.

After performing the preliminary discharge for a predetermined time, the dummy semiconductor wafer 7 is transferred onto the wafer unloading / importing belt 8 by the rotating arm 9. Next, the dummy semiconductor wafer 7 is transferred to the original position in the dummy semiconductor wafer cassette 5 placed in the dummy semiconductor wafer chamber 3 by the wafer unloading / loading belt 8.

Next, the gate valve 18 is opened again, and the processing semiconductor wafers 6 in the processing semiconductor wafer cassette 4 are transferred one by one onto the wafer unloading / carrying belt 8. The processing semiconductor wafer 6 transferred to the wafer unloading / loading belt 5 in this manner is transferred to the wafer unloading / loading belt 8.
Are carried to the vicinity of the discharge chamber 11.

Next, the processing semiconductor wafer 6 is transferred by the rotating arm 9 onto the stage (lower electrode) 10 in the discharge chamber 11. A predetermined etching gas is introduced into the discharge chamber 11 according to the material to be etched. Then R
An RF voltage is applied to the stage (lower electrode) 10 by the F power supply. Thereby, plasma is generated in the discharge chamber 11 to etch a desired film on the processing semiconductor wafer 6.

After the etching process is completed, the processing semiconductor wafer 6 is transferred onto the wafer carry-out / carry-in belt 8 by the rotating arm 9. After that, the processing semiconductor wafer 6 is transferred to the original position of the processing semiconductor wafer cassette 4 which is grounded in the processing semiconductor wafer chamber 2.
In this case, at the stage when the etching processing of the 25 processing semiconductor wafers 6 in the processing semiconductor wafer cassette 4 is completed and the 25 processing semiconductor wafers 6 are stored again in the processing semiconductor cassette 4. The processing semiconductor wafer 6 is taken out from the processing semiconductor wafer chamber 2 together with the processing semiconductor wafer cassette 4 and sent to the next step. Further, since one dummy semiconductor wafer 7 is used for each set of the processing semiconductor wafer cassettes 4, the dummy semiconductor wafer cassettes 4 are processed after 25 sets of etching processing of the processing semiconductor wafer cassettes 4 are completed. 5, the dummy semiconductor wafer 7 is taken out and is replaced with the dummy semiconductor wafer cassette 5 containing a new dummy semiconductor wafer 7. In the case where the dummy semiconductor wafer is used for the etching process according to the above-described embodiment, referring to FIG. 2, the dummy semiconductor wafer is used for the time t ₃ until the upper electrode temperature reaches the saturation temperature T ° C. By performing the preliminary discharge and then continuously processing the semiconductor wafers for the etching process, in this embodiment, all of the 25 processing semiconductor wafers 6 housed in the processing semiconductor wafer cassette 4 are made uniform. Can be etched. Further, as shown in FIGS. 3 and 4, by using a dummy wafer for the processing portions corresponding to the first to third conventional wafers, it is possible to make all the etching characteristics of the semiconductor wafer for subsequent processing uniform. Become. Although the RG plasma etching apparatus has been described in the above embodiment, similar effects can be obtained in the sputter beam etching apparatus and the ion beam etching apparatus.

[0037]

According to the single-wafer type dry etching apparatus and the dry etching method using the apparatus according to the present invention, first, a dummy semiconductor wafer is carried into a processing chamber, a preliminary discharge is performed, and then a dry discharge is performed. The semiconductor wafer to be subjected to the etching process is carried into the processing chamber and main discharge is performed.

As a result, by performing preliminary discharge using the dummy semiconductor wafer, main discharge is performed on the processing semiconductor wafer in the state where the upper electrode is set to the saturation temperature T ° C. in advance. All the etching characteristics of the processing semiconductor wafer in the semiconductor wafer cassette can be made uniform. Further, by providing the dummy semiconductor wafer chamber and the processing semiconductor wafer chamber, it is possible to uniformly etch all the semiconductor wafers loaded into the processing semiconductor wafer chamber. On the other hand, the dummy semiconductor wafers loaded into the dummy semiconductor wafer chamber can store, for example, 25 dummy semiconductor wafers because one dummy semiconductor wafer is used for one set of processing semiconductor wafer cassettes. When such a dummy semiconductor wafer cassette is used, it is only necessary to replace it each time 25 sets of processing semiconductor wafer cassettes are processed, so that it is possible to improve the workability.

[Brief description of drawings]

FIG. 1 is a partial plan sectional view of a single-wafer dry etching apparatus according to the present invention.

FIG. 2 is a diagram showing a relationship between a discharge time and an upper electrode temperature in a dry etching method using a single wafer type dry etching apparatus according to the present invention.

FIG. 3 is a diagram showing the relationship between the number of processed wafers and the etching rate in-plane uniformity in a dry etching method using a single wafer type dry etching apparatus according to the present invention.

FIG. 4 is a diagram showing the relationship between the number of wafers processed and the etching rate in the dry etching method using the single wafer type dry etching apparatus according to the present invention.

FIG. 5 is a schematic view showing the operating principle of the dry etching method.

FIG. 6 is a partial plan sectional view of a conventional single-wafer dry etching apparatus.

FIG. 7 is a partial vertical cross-sectional view of a conventional single-wafer dry etching apparatus.

FIG. 8 is a diagram showing a relationship between a discharge time and an upper electrode temperature in a dry etching method using a conventional single-wafer dry etching apparatus.

FIG. 9 is a diagram showing a relationship between the number of processed semiconductor wafers and in-plane uniformity of an etching rate in a dry etching method using a conventional single-wafer dry etching apparatus.

FIG. 10 is a diagram showing a relationship between the number of processed semiconductor wafers and an etching rate in a dry etching method using a single-wafer dry etching apparatus in the related art.

[Explanation of symbols]

 1 Vacuum Container 2 Processing Semiconductor Wafer Chamber 3 Dummy Semiconductor Wafer Chamber 4 Processing Semiconductor Wafer Cassette 5 Dummy Semiconductor Wafer Cassette 6 Processing Semiconductor Wafer 7 Dummy Semiconductor Wafer 8 Wafer Unloading / Loading Belt 9 Rotating Arm 10 Stage ( Lower electrode) 11 discharge chamber 12 transfer chamber 14 upper electrode 18 gate valve In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A processing chamber for performing a dry etching process on a semiconductor wafer, a dummy semiconductor wafer loading / unloading means for loading and unloading a dummy semiconductor wafer into the processing chamber, and a dry etching process for the processing chamber. A single-wafer dry etching apparatus comprising: a processing semiconductor wafer loading / unloading means for loading and unloading a semiconductor wafer to be processed. 2. A step of loading a dummy semiconductor wafer into a processing chamber for performing a dry etching process on the semiconductor wafer and performing preliminary discharge for a predetermined time; and a step of unloading the dummy semiconductor wafer out of the processing chamber. After the step of unloading the dummy semiconductor wafer,
The operation of loading the processing semiconductor wafers to be subjected to the etching processing one by one into the processing chamber, performing the main discharge, performing the dry etching, and carrying out the processing chamber is performed continuously for a predetermined number of the processing semiconductor wafers. A single-wafer dry etching method including steps to be performed.