JP3208067B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for manufacturing a semiconductor device manufactured by dry etching of an insulating film.

[0002]

2. Description of the Related Art A conventional insulating film formed on a silicon substrate
An example of the pattern forming process will be described with reference to FIG. Figure
As shown in FIG. 4 (a), a silicon oxide
An insulating film 12 such as a silicon film or a silicon nitride film is grown.
Then, a predetermined portion on the insulating film 12 is
Cover with 3. After this, containing carbon and fluorine, for example, CF
_FourAnd CHF_ThreeGas mixture as an etching gas
Then, dry etching is performed to form the insulating film 12.
The part 14 not covered with the photoresist 13 is removed.
At the time of the dry etching, as shown in FIG.
A polymer film containing carbon and fluorine is formed on the surface of the substrate 15 to be processed.
A fluorocarbon film 16 is deposited. After this,
The photoresist 13 and the fluorocarbon film 16
It is removed by ashing using gas. At this time,
In order to increase the ashing speed, the substrate 1
5 is controlled from 150 ° C to 250 ° C.
Was.

[0003]

However, in the above-described conventional method for manufacturing a semiconductor device, the temperature of the substrate 15 to be processed is controlled to a high temperature of 150 ° C. to 250 ° C. during ashing, so that the surface of the substrate 15 to be processed Since the underlying silicon substrate 11 is etched by fluorine radicals generated from the deposited fluorocarbon film 16 as shown in FIG. 4C, junction leaks and contact failures are likely to occur, and there is a problem in reliability. Was.

An object of the present invention is to provide a method of manufacturing a semiconductor device in which a base silicon substrate and a polycrystalline silicon film are hardly etched during ashing.

[0005]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming an insulating film on a silicon substrate or a polycrystalline silicon film; and forming a photoresist covering a predetermined portion on the insulating film. Forming, and removing the insulating film in a portion not covered with the photoresist by dry etching using an etching gas containing carbon and fluorine, and a predetermined portion of the insulating film by the dry etching. While controlling the temperature of the stage on which the substrate to be processed is removed to 100 ° C. or less,
Removing the fluorocarbon film deposited on the surface of the substrate to be processed and the photoresist during the dry etching by ashing using only oxygen gas.

According to the method of manufacturing a semiconductor device according to the first aspect, since the temperature during ashing is controlled to a low temperature of 100 ° C. or less, the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow.
The underlying silicon substrate or polycrystalline silicon film is less likely to be etched. 3. The method of manufacturing a semiconductor device according to claim 2, wherein: a step of forming an insulating film on a silicon substrate or a polycrystalline silicon film; a step of forming a photoresist covering a predetermined portion on the insulating film; Removing a portion of the insulating film which is not covered by dry etching using an etching gas containing carbon and fluorine, and installing a substrate to be processed from which a predetermined portion of the insulating film has been removed by the dry etching. Removing the fluorocarbon film deposited on the surface of the target substrate by ashing using only oxygen gas during the dry etching while controlling the temperature of the stage to be 100 ° C. or lower, and after removing the fluorocarbon film, The temperature of the stage on which the substrate to be processed is installed is raised to an arbitrary temperature from 150 ° C. to 250 ° C. It is intended to include removing by ashing using the photoresist only oxygen gas.

According to the method of manufacturing a semiconductor device of the present invention, the temperature during the ashing of the fluorocarbon film is set to 100.
Since the temperature is controlled to be lower than or equal to ° C., the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow, and the underlying silicon substrate or polycrystalline silicon film is hardly etched. Further, since the photoresist can be removed by ashing at a high temperature of 150 ° C. to 250 ° C., the ashing speed is increased, and the ashing time can be shortened.

According to a third aspect of the invention, there is provided a method of manufacturing a semiconductor device.
A step of forming an insulating film on a silicon substrate or a polycrystalline silicon film, a step of forming a photoresist covering a predetermined portion on the insulating film, and a portion of the insulating film not covered with the photoresist, The step of removing by dry etching using an etching gas containing carbon and fluorine, and the temperature of a stage on which a substrate to be processed in which a predetermined portion of the insulating film is removed by the dry etching is continuously set from 100 ° C. or less. Removing the fluorocarbon film deposited on the surface of the substrate to be processed during the dry etching and the photoresist by ashing using only oxygen gas.

According to a third aspect of the present invention, the temperature during the ashing of the fluorocarbon film is set to 100.
Since the temperature is controlled to be lower than or equal to ° C., the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow, and the underlying silicon substrate or polycrystalline silicon film is hardly etched. In addition, by continuously increasing the temperature of the substrate to be processed, the photoresist can be removed by ashing at a high temperature, so that the ashing speed increases and the ashing time can be reduced.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

 First Embodiment A first embodiment of the present invention will be described with reference to FIG.
I will tell. First, as shown in FIG.
After a silicon oxide film (insulating film) 2 is grown on
A predetermined portion of the silicon nitride film 2 is covered with a photoresist 3.
U. Thereafter, the silicon oxide film 2 is covered with the photoresist 3.
The part 4 that is not touched is CF _FourAnd CHF_ThreeGas mixture
It is removed by dry etching using a etching gas.
In this embodiment, the gas pressure is 133 Pa, the RF power is 1
The test was performed under kW conditions. At this time, as shown in FIG.
Thus, the fluorocarbon film 6 is deposited on the surface of the substrate 5 to be processed.
I do.

Thereafter, the fluorocarbon film 6 deposited on the surface of the photoresist 3 and the substrate 5 to be processed is removed by ashing using oxygen gas. Ashing uses a single-wafer ashing device. The temperature of the stage on which the substrate 5 is set is controlled to 100 ° C. or less. In this embodiment, the temperature is set to 80 ° C. After introducing the substrate 5 into the processing chamber, oxygen gas is introduced to generate plasma (in this embodiment, the gas pressure is 133 Pa, the RF power is 500).
W), and as shown in FIG. 1C, the fluorocarbon film 6 and the photoresist 3 deposited on the surface of the processing target substrate 5 are completely removed by ashing.

According to the method of manufacturing a semiconductor device having the above-described structure, the temperature of the substrate 5 to be processed during ashing is set to 10 degrees.
Since the temperature is controlled to a low temperature of 0 ° C. or less, the etching rate of silicon by fluorine radicals generated from the fluorocarbon film 6 becomes very slow, and as shown in FIG. 1C, the underlying silicon substrate 1 is hardly etched. Therefore, problems such as a junction leak and a contact failure are eliminated, and the reliability of a semiconductor device manufactured using dry etching of the insulating film 2 can be greatly improved.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. First, as shown in FIG. 2A, after a silicon oxide film 2 is grown on a silicon substrate 1, a predetermined portion of the silicon oxide film 2 is covered with a photoresist 3. After this,
The portion 4 of the silicon oxide film 2 not covered with the photoresist 3 is removed by dry etching using a mixed gas of CF ₄ and CHF ₃ as an etching gas as shown in FIG. After the substrate 5 to be processed is introduced into the processing chamber of the single-wafer ashing apparatus in which the temperature of the stage on which is installed is controlled to 100 ° C. or lower (80 ° C. in the present embodiment), oxygen gas is introduced into the processing chamber. Figure 2
As shown in (c), the fluorocarbon film 6 deposited on the surface of the substrate 5 to be processed by ashing is completely removed.

Thereafter, the temperature of the stage on which the substrate 5 to be processed shown in FIG. 2 (c) is installed is raised to an arbitrary temperature from 150 ° C. to 250 ° C. (in the present embodiment, 160 ° C.) As shown in FIG. 2D, the photoresist 3 remaining on the substrate 5 to be processed is removed by ashing. According to the method of manufacturing a semiconductor device configured as described above, if the fluorocarbon film 6 on the surface of the substrate 5 is removed by ashing while controlling the substrate 5 to 100 ° C. or less, Even if the photoresist 3 remaining on the substrate 5 is removed by ashing at a high temperature such as 150 ° C. to 250 ° C., the underlying silicon substrate 1 is hardly etched as shown in FIG. Therefore, problems such as a junction leak and a contact failure are eliminated, and the reliability of a semiconductor device manufactured using dry etching of the insulating film 2 can be greatly improved.

Further, the photoresist 3 is heated from 150 ° C. to 2 ° C.
Since it can be removed by ashing at a high temperature such as 50 ° C., the ashing speed increases and the ashing time can be reduced. Third Embodiment A third embodiment of the present invention will be described with reference to FIG.

First, as shown in FIG. 2A, after a silicon oxide film 2 is grown on a silicon substrate 1, a predetermined portion of the silicon oxide film 2 is covered with a photoresist 3. Thereafter, a portion 4 of the silicon oxide film 2 which is not covered with the photoresist 3 is removed with CF ₄ and CHF as shown in FIG.
A single-wafer ashing apparatus in which the temperature of the stage on which the substrate 5 to be processed is removed is controlled to 100 ° C. or lower (80 ° C. in the present embodiment) after removing by dry etching using the mixed gas of _{3 as} an etching gas. After the substrate 5 to be processed is introduced into the processing chamber of FIG.
As shown in (c), the fluorocarbon film 6 deposited on the surface of the substrate 5 to be processed by ashing is completely removed.

After completely removing the fluorocarbon film 6 deposited on the surface of the substrate 5 by ashing, the ashing is stopped. Thereafter, the substrate 5 to be processed is taken out of the ashing processing chamber, and another single-wafer ashing in which the temperature of the stage on which the substrate 5 is installed is controlled from 150 ° C. to 250 ° C. (160 ° C. in the present embodiment). The processing target substrate 5 is moved to the processing chamber of the apparatus, and the remaining photoresist 3 is removed by ashing.

According to the method of manufacturing a semiconductor device having such a configuration, the same effects as those of the second embodiment can be obtained. Furthermore, since two types of processing chambers having different set temperatures are used, there is no need to change the temperature in the same processing chamber, and a stable ashing process can be performed. Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 3A, the silicon substrate 1
After the silicon oxide film 2 is grown thereon, a predetermined portion of the silicon oxide film 2 is covered with a photoresist 3. Thereafter, as shown in FIG. 3B, a portion 4 of the silicon oxide film 2 which is not covered with the photoresist 3 is removed by dry etching using a mixed gas of CF ₄ and CHF ₃ as an etching gas. At this time, a fluorocarbon film 6 is deposited on the surface of the substrate 5 to be processed as shown in FIG.

Thereafter, ashing is performed using a barrel-type batch type ashing apparatus. The temperature of the processing chamber before starting the ashing process is controlled to a low temperature of 50 ° C. to 100 ° C. (60 ° C. in the present embodiment). After the substrate 5 shown in FIG. 3B is introduced into the processing chamber, oxygen gas is introduced,
Generates plasma. In the barrel-type batch ashing apparatus, the temperature of the processing chamber usually rises from 200 ° C. to 250 ° C. due to the heat of reaction between oxygen and the photoresist 3 at the start of ashing (230 in this embodiment).
° C). In this way, as shown in FIG. 3C, the fluorocarbon film 6 and the photoresist 3 are removed by ashing.

According to the method of manufacturing a semiconductor device having the above-described structure, the temperature of the processing chamber before the start of processing is reduced from 50 ° C. to 1 °.
Since the temperature is controlled to be as low as 00 ° C., the fluorocarbon film 6 deposited on the surface can be removed at a low temperature. After that, since the temperature of the processing chamber rises from 200 ° C. to 250 ° C., it remains at a high temperature. The photoresist 3 can be removed by ashing. For this reason, as shown in FIG. 3C, the underlying silicon substrate 1 is hardly etched, and there are no problems such as junction leakage and contact failure, and the reliability of the semiconductor device manufactured by dry etching of the insulating film 2 is reduced. A great improvement in performance can be realized. Further, the ashing speed is increased, and the ashing time can be reduced.

In the above embodiment, the example using the silicon substrate 1 has been described. However, the same effect can be obtained when a polycrystalline silicon film is used. Further, although the silicon oxide film is used for the insulating film 2, a silicon nitride film or the like may be used. Further, an example in which oxygen gas is used as the ashing gas has been described . Further, CF _{4 is used} as a dry etching gas for the insulating film 2.
An example using a gas mixture of CHF ₃ and CHF ₃ has been described, but any gas may be used as long as the gas contains carbon and fluorine.
Similar effects can be obtained.

[0023]

According to the method of manufacturing a semiconductor device according to the present invention, since the temperature during ashing is controlled to a low temperature of 100 ° C. or less, the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow. Then, the underlying silicon substrate or polycrystalline silicon film is hardly etched. Therefore, problems such as junction leakage and contact failure are eliminated, and the effect of significantly improving the reliability of a semiconductor device manufactured using dry etching of an insulating film can be obtained.

According to the semiconductor device manufacturing method of the present invention, the temperature during the ashing of the fluorocarbon film is set to 100.
Since the temperature is controlled to be lower than or equal to ° C., the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow, and the underlying silicon substrate or polycrystalline silicon film is hardly etched. Therefore, problems such as a junction leak and a contact failure are eliminated, and the reliability of a semiconductor device manufactured using dry etching of an insulating film can be significantly improved. Further, since the photoresist can be removed by ashing at a high temperature such as 150 ° C. to 250 ° C., the ashing speed is increased and the ashing time can be shortened.

According to the third aspect of the present invention, the temperature during the ashing of the fluorocarbon film is set to 100.
Since the temperature is controlled to be lower than or equal to ° C., the etching rate of silicon by fluorine radicals generated from the fluorocarbon film becomes very slow, and the underlying silicon substrate or polycrystalline silicon film is hardly etched. Therefore, problems such as a junction leak and a contact failure are eliminated, and the reliability of a semiconductor device manufactured using dry etching of an insulating film can be significantly improved. Further, by continuously increasing the temperature of the substrate to be processed, the photoresist can be removed by ashing at a high temperature, so that the ashing speed is increased and the ashing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a manufacturing step in order to explain a first embodiment of the present invention.

FIG. 2 is a cross-sectional view in the order of manufacturing steps for explaining second and third embodiments of the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing step in order to explain a third embodiment of the present invention.

FIG. 4 is a sectional view in order of a manufacturing process for explaining a conventional ashing method. .

[Description of Signs] 1 Silicon substrate 2 Silicon oxide film (insulating film) 3 Photoresist 4 Portion of insulating film not covered with photoresist 5 Substrate to be processed 6 Fluorocarbon film

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-321090 (JP, A) JP-A-63-202920 (JP, A) JP-A-4-229621 (JP, A) JP-A-7-202 29879 (JP, A) JP-A-8-64580 (JP, A) JP-A-5-217960 (JP, A) JP-A-6-177088 (JP, A) JP-A 8-167590 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/3065 H01L 21/027

Claims (3)

(57) [Claims] A step of forming an insulating film on a silicon substrate or a polycrystalline silicon film; a step of forming a photoresist covering a predetermined portion on the insulating film; Removing the insulating film by dry etching using an etching gas containing carbon and fluorine; and setting the temperature of a stage for setting a substrate on which a predetermined portion of the insulating film has been removed by the dry etching to 10
Removing the fluorocarbon film and the photoresist deposited on the surface of the substrate during the dry etching by ashing using only oxygen gas while controlling the temperature to 0 ° C. or lower. 2. A step of forming an insulating film on a silicon substrate or a polycrystalline silicon film; a step of forming a photoresist covering a predetermined portion on the insulating film; Removing the insulating film by dry etching using an etching gas containing carbon and fluorine; and setting the temperature of a stage for setting a substrate on which a predetermined portion of the insulating film has been removed by the dry etching to 10
Removing the fluorocarbon film deposited on the surface of the processing substrate by ashing using only oxygen gas during the dry etching while controlling the temperature to 0 ° C. or lower; and removing the fluorocarbon film after removing the fluorocarbon film. Raise the temperature of the stage to be installed to an arbitrary temperature from 150 ° C. to 250 ° C., and apply oxygen gas to the photoresist.
Removing by ashing using only a semiconductor device. 3. A step of forming an insulating film on a silicon substrate or a polycrystalline silicon film; a step of forming a photoresist covering a predetermined portion on the insulating film; Removing the insulating film by dry etching using an etching gas containing carbon and fluorine; and setting the temperature of a stage for setting a substrate on which a predetermined portion of the insulating film has been removed by the dry etching to 10
Removing the fluorocarbon film deposited on the surface of the substrate during the dry etching and the photoresist by ashing using only oxygen gas while continuously increasing the temperature from 0 ° C. or less. .