JP2002217167A - Method for fabricating semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for fabricating a semiconductor device, in which generation of defectives are suppressed by stabilizing etching property. SOLUTION: The semiconductor device is produced by forming contact hole on the insulation film on a patterned silicon substrate using an semiconductor fabricating equipment having at least a reaction chamber for generating plasma. The plasma comprised of argon and oxygen is generated (step S1) in the reaction chamber of the semiconductor fabricating equipment before a contact hole (step S3) in the insulation film on the semiconductor substrate is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device using a semiconductor manufacturing apparatus, and more particularly to a method of manufacturing a semiconductor device by forming a contact hole in an insulating film of a silicon substrate using a plasma etching apparatus. .

[0002]

2. Description of the Related Art In recent years, high integration and reduction in size of semiconductor devices have been demanded, and accordingly, dimensions (width) of wiring have been increased.
It is also required to reduce the dimensions (opening diameter) of contact holes. However, taking the step of forming a contact hole as an example, the thickness of the interlayer insulating film is not reduced in spite of the fact that the size of the contact hole is reduced, and the thickness of the insulating film with respect to the size of the contact hole is reduced. Ratio (aspect ratio) tends to increase. Therefore, in order to realize a highly integrated semiconductor device, it is important to establish an etching technique capable of forming a contact hole having a high aspect ratio.

In general, a plasma etching apparatus is used to form such a high aspect ratio contact hole. The plasma etching apparatus has a reaction chamber, in which plasma is generated, and this plasma generates
A contact hole is formed in an insulating film provided on a silicon substrate. Therefore, a contact hole having a high aspect ratio can be easily formed.

Among the plasma etching apparatuses, ones particularly suitable for forming a contact hole having a high aspect ratio include an inductively-coupled plasma generator and a dual-frequency capacitively-coupled plasma generator capable of generating high-density plasma at a low gas pressure. As a plasma generation source.

[0005]

In the plasma etching apparatus described above, a temperature control device is usually mounted on a member constituting the reaction chamber in order to stably perform etching while keeping the temperature in the reaction chamber constant. Have been.

However, since the members constituting the reaction chamber receive the radiation heat of the plasma during the etching, the surface temperature of the portion facing the plasma gradually increases from the start of the etching even if a temperature control device is used. As a result, the etching characteristics change particularly after a certain period of time from the start, causing a problem that adjacent contact holes are connected to each other and a problem that a diffusion layer exposed at the bottom of the contact hole is etched. As a result, the silicon substrate becomes defective.

An object of the present invention is to provide a method of manufacturing a semiconductor device which can stabilize etching characteristics and suppress occurrence of defective products.

[0008]

According to a first aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising the steps of: providing a semiconductor manufacturing apparatus having a reaction chamber for generating plasma; A method of manufacturing a semiconductor device in which a contact hole is formed in an insulating film formed in the above, wherein before forming a contact hole in the insulating film, a plasma comprising argon gas and oxygen gas is previously applied to the reaction chamber for a predetermined time. It is characterized by having a step of generating.

In the first aspect, it is preferable that the generation of the plasma be performed until the surface temperature in a portion of the reaction chamber facing the plasma is saturated.

In order to achieve the above object, a second aspect of the method of manufacturing a semiconductor device according to the present invention uses a semiconductor manufacturing apparatus having a reaction chamber for generating plasma.
A method of manufacturing a semiconductor device in which a contact hole is formed in an insulating film formed on a silicon substrate, wherein: (1) placing a dummy silicon substrate in the reaction chamber before forming the contact hole in the insulating film; In this state, a step of generating plasma containing a fluorocarbon gas as a main component in the reaction chamber and (2) a step of generating an oxygen plasma in the reaction chamber to remove a polymer film formed by the plasma, It is characterized in that the surface temperature in a portion of the reaction chamber facing the plasma is saturated.

In the second aspect, the step (1) and the step (2) are repeated a plurality of times, and each time the step is repeated, the dummy silicon substrate is replaced with another dummy silicon substrate. You can also. Furthermore, the second
In the aspect, the step (1) and the step (2) may be repeated without replacing the dummy silicon substrate.

In the first and second aspects, the formation of the contact hole in the patterned silicon substrate insulating film is performed by generating plasma containing fluorocarbon as a main component in the reaction chamber. Is preferred.

In the first and second aspects, the fluorocarbon gas is CH ₂ F ₂ gas, CH ₂ F ₂ gas,
₃ F gas, C ₂ F ₆ gas, C ₃ F ₈ gas, C ₄ F ₆ gas, C ₄ F
Preferably, it contains at least one gas selected from ₈ gases and C ₅ F ₈ gas.

In the first and second aspects, the semiconductor manufacturing apparatus includes a high-frequency power supply for generating plasma and a power supply for applying a DC voltage to the silicon substrate, and each power supply is independently provided. It preferably has a function of controlling.

In the first and second aspects, the semiconductor manufacturing apparatus may be a capacitively coupled plasma generator, a dual-frequency capacitively coupled plasma generator, an inductively coupled plasma generator, a microwave plasma generator, or a VH.
It is preferable that at least one selected from F plasma generators is provided as a plasma generation source.

[0016]

(Embodiment 1) Hereinafter, a method of manufacturing a semiconductor device according to Embodiment 1 of the present invention will be described.
This will be described with reference to FIGS. FIG. 1 is a cross-sectional view illustrating an example of a semiconductor manufacturing apparatus used in the method for manufacturing a semiconductor device according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the method of manufacturing the semiconductor device according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating the effect of the method for manufacturing a semiconductor device according to the first embodiment of the present invention.

The semiconductor manufacturing apparatus shown in FIG. 1 is a plasma etching apparatus in which an inductively coupled plasma generator is used as a plasma generation source. The plasma generation source is not limited to this, but may also include a capacitively coupled plasma generator, a dual-frequency capacitively coupled plasma generator, a microwave plasma generator, a VHF plasma generator, and the like.

In FIG. 1, reference numeral 1 denotes a disk-shaped upper electrode, which forms the upper surface of a reaction chamber 6. Reference numeral 2 denotes a high-frequency power supply for generating plasma.
By applying high-frequency power to zero, plasma is generated in the reaction chamber 6. Reference numeral 3 denotes a lower electrode.
A silicon ring 11 is further provided on the top. 5
Is a silicon substrate to be processed;
Is formed with a patterned insulating film (not shown). The silicon substrate 5 is a silicon ring 11
Is held on the lower electrode 3.

Reference numeral 17 denotes a DC power supply for applying a DC voltage to the silicon substrate 5 via the lower electrode 3. DC power supply 17
When a DC voltage is applied to the silicon substrate 5 from above, the silicon substrate 5 is electrostatically attracted to the lower electrode 3. In the semiconductor manufacturing apparatus shown in the example of FIG.
And the DC power supply 17 can be controlled independently of each other. As described above, since the power supply can be controlled independently, the semiconductor manufacturing apparatus shown in FIG. 1 has an effect that the etching rate can be increased and the substrate damage can be reduced.

Reference numeral 4 denotes a silicon substrate 5 via the lower electrode 3.
This is a high-frequency power supply that applies high-frequency power to the power supply. When high-frequency power is applied from the high-frequency power supply 4 to the silicon substrate 5, a high-frequency voltage is generated on the silicon substrate 5, ions for etching are drawn into the silicon substrate 5, and as a result, the insulation formed on the silicon substrate 5 is formed. The film is etched.

Reference numeral 7 denotes a turbo molecular pump for reducing the pressure inside the reaction chamber 6, and reference numeral 8 denotes a dry pump. Reference numeral 9 denotes a gas inlet for introducing a gas for generating plasma into the reaction chamber. Reference numeral 12 denotes a cylindrical quartz dome, which constitutes a side wall of the reaction chamber 6. As described above, the reaction chamber 6 includes the upper electrode 1, the quartz dome 12, and the lower electrode 3, and is a space surrounded by these.

The interior of the reaction chamber 6 is depressurized by a turbo molecular pump 7 and a dry pump 8 during etching, and is kept at a vacuum. An annular heater 14 is attached to the upper surface of the upper electrode 1. Further, an annular heater 13 is attached to the outer surface of the quartz dome 12. Therefore, the temperature of the upper electrode 1 and the temperature of the quartz dome 12 are precisely controlled. The heater 13 is a heater power supply 1
5, the heater 14 is controlled by a heater power supply 16. During normal etching, the upper electrode 1
Is controlled to about 250 ° C., and the temperature of the quartz dome 12 is controlled to about 240 ° C.

Next, a method of manufacturing the semiconductor device according to the first embodiment of the present invention will be described for each step with reference to FIG. In the following, the constituent members of the semiconductor manufacturing apparatus are given the numbers shown in FIG.

As shown in FIG. 2, first, a plasma composed of an argon gas and an oxygen gas is generated in the reaction chamber 6 of the semiconductor manufacturing apparatus (step S1). Specifically, an argon gas and an oxygen gas are introduced into the reaction chamber 6 from the gas inlet 9, and high-frequency power is applied to the coil 10 by the high-frequency power supply 2 to generate plasma (see FIG. 1). At this time, the silicon substrate 5 has not been carried into the reaction chamber 6 and nothing is disposed on the lower electrode 3.

The plasma is generated until the surface temperature of the portion facing the plasma in the reaction chamber 6, for example, the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 is saturated. When the surface temperature is saturated, the outputs of the high frequency power supply 2 and the high frequency power supply 4 are turned off to extinguish the plasma. The saturation of the surface temperature will be described later with reference to FIG.

Next, the silicon substrate 5 to be processed is carried into the reaction chamber 6 (step S2). Silicon substrate 5
Are arranged on the lower electrode 3 and held by the silicon ring 11 (see FIG. 1). An insulating film patterned with a photoresist is formed on the silicon substrate 5. The patterning is performed so that a portion serving as a contact hole is exposed. The insulating film is not particularly limited as long as it is an insulating film constituting a semiconductor chip.
SG (Bron-Phosphine-Silicate-Glass) film and the like.

Next, plasma containing fluorocarbon as a main component is generated in the reaction chamber 6, thereby etching the insulating film of the silicon substrate 5 (step S3). Specifically, for example, C ₂ F ₆ is introduced into the reaction chamber 6 from the gas inlet 9.
A plasma is generated by introducing a fluorocarbon gas such as a / O ₂ mixed gas or a C ₅ F ₈ / Ar / O ₂ mixed gas, and applying high frequency power to the coil 10 by the high frequency power supply 2 (see FIG. 1). At the same time, a DC voltage is applied to the lower electrode 3 by a DC power supply 17 to cause the silicon substrate 5 and the lower electrode 3 to be electrostatically attracted. A high-frequency voltage is generated (see FIG. 1). As a result, ions to be etched are drawn into the silicon substrate 5, and a portion of the insulating film on the silicon substrate 5 exposed from the photoresist is etched to form a contact hole. After the formation of the contact holes, the outputs of the high frequency power supply 2 and the high frequency power supply 4 are turned off to extinguish the plasma.

The fluorocarbon gas referred to in the present invention includes CH ₂ F ₂ gas, CH ₃ F gas, C ₂ F ₆ gas, C ₃ F ₈
Any gas containing at least one gas selected from gas, C ₄ F ₆ gas, C ₄ F ₈ gas, and C ₅ F ₈ gas may be used, and is not particularly limited.

Next, oxygen plasma is generated in the reaction chamber 6, and the polymer film formed by the generation of the plasma in step S3 is removed (step S4). Specifically, oxygen gas is introduced into the reaction chamber 6 from the gas inlet 9,
High frequency power is applied to the coil 10 by the high frequency power supply 2 to generate plasma (see FIG. 1). At the same time, similarly to the above, the silicon substrate 5 and the lower electrode 3 are electrostatically attracted to generate a high-frequency voltage on the silicon substrate 5 (see FIG. 1). As a result, oxygen ions are attracted, and the polymer film adhered to the bottom of the contact hole and the polymer film adhered to the lower surface of the upper electrode 1, the upper surface of the quartz dome 12, and the surface of the silicon ring 11 are removed by the oxygen ions. The inside of the chamber 6 is cleaned.

Finally, the silicon substrate 5 having the contact hole formed therein is carried out of the reaction chamber 6 (step S).
5). This silicon substrate 5 becomes a product. When processing the silicon substrate 5 continuously, steps S2 to S5 may be repeated. As described above, in the method for manufacturing a semiconductor device according to the first embodiment, before the contact hole is formed by etching the insulating film of the silicon substrate 5 (step S2), the argon is formed in the reaction chamber 6 of the semiconductor manufacturing device. A plasma composed of a gas and an oxygen gas is generated (step S1).

Next, the effect of the method for manufacturing a semiconductor device according to the first embodiment will be described in comparison with a conventional method for manufacturing a semiconductor device with reference to FIG. Note that the conventional method of manufacturing a semiconductor device here is the same as that in step S1 in FIG.
Is performed, and only steps S2 to S5 are performed.

FIG. 3A shows the relationship between the BPSG etching rate and the number of processed wafers in the semiconductor device manufacturing method according to the present embodiment and the conventional semiconductor device manufacturing method. The BPSG etching rate is measured by providing a flat BPSG film (insulating film) on a silicon substrate and performing etching on the BPSG film using plasma containing a fluorocarbon gas as a main component. As shown in FIG. 3A, the BPSG etching rate is the same between the conventional and the present invention.

FIG. 3B shows the relationship between the resist etching rate and the number of processed wafers in the semiconductor device manufacturing method according to the present embodiment and the conventional semiconductor device manufacturing method. The resist etching rate is BP of silicon substrate
The SG film is patterned with a photoresist, and the portion exposed from the photoresist is measured by etching with a plasma mainly containing a fluorocarbon gas.

FIG. 3C shows the relationship between the resist selectivity and the number of processed wafers in the semiconductor device manufacturing method according to the present embodiment and the conventional semiconductor device manufacturing method. The resist selectivity is the ratio of the BPSG etching rate shown in FIG. 3A to the resist etching rate shown in FIG. 3B (BPSG etching rate / resist etching rate).

As shown in FIGS. 3B and 3C, according to the conventional method for manufacturing a semiconductor device, the resist etching rate decreases as the number of processed wafers increases, and conversely, the resist selectivity to resist selection ratio increases. Are higher with an increase in the number of processed sheets, and these are not stable until the third processed sheet and are stable from the fourth processed sheet.

By the way, when plasma is generated in the reaction chamber 6, a portion of the plasma facing the plasma in the reaction chamber 6, ie, the lower surface of the upper electrode 1 and the quartz dome 12 in the example of FIG. The surface temperature on the inner surface and the upper surface of the silicon ring 11 rises by about 10 ° C. to 100 ° C. and eventually stabilizes at a certain temperature. Such a state is referred to as “surface temperature saturation” in the present invention. Note that the actual surface temperature when the surface temperature is saturated is about 240 ° C to 400 ° C.

Further, since these components usually contain silicon, when the surface temperature increases, the silicon contained in the components bonds with fluorine in the plasma. For this reason, the fluorine concentration ratio in the plasma gradually decreases, the carbon concentration ratio gradually increases, and these are eventually stabilized.

In the conventional method for manufacturing a semiconductor device, the silicon substrate (the first to third substrates shown in FIG. 3) is processed in a state where the surface temperatures of these components are not saturated. Etching will be performed when the ratio changes from a low state to a high state. Therefore, the resist etching rate decreases as the number of processed wafers increases,
Conversely, it is considered that the selectivity to resist is increased.

When etching is performed in this state, B
Even the photoresist provided on the PSG film (insulating film) is etched, and part or all of the photoresist disappears. As a result, the BPSG film immediately below the photoresist is etched, and the size of the contact hole becomes large, as described above, and the adjacent contact holes are connected to each other. Further, there is a problem that the diffusion layer exposed at the bottom of the contact hole is etched.

On the other hand, in the method of manufacturing a semiconductor device according to the present embodiment, as shown in FIG. 2, first, a plasma is generated with argon gas and oxygen gas (step S1), and the plasma is radiated. The surface temperatures of the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 are saturated by heat, and thereafter, the insulating film of the silicon substrate is etched. In this case, the value of the high-frequency power (RF power) applied from the high-frequency power supply 2 is not particularly limited, but is preferably about 3000 W from the viewpoint of shortening the discharge time. For example, the high frequency power applied from the high frequency power supply 2 is 2700
In the case of W, the required discharge time is about 10 minutes.
In the case of 00W, the required discharge time is about 7 minutes.

Therefore, according to the present embodiment, even when the first silicon substrate is etched, the fluorine concentration ratio and the carbon concentration ratio in the plasma are stable at constant values, and the resist etching rate and The resist selectivity is also stable. Therefore, even when the first to third silicon substrates are being etched, the possibility that the photoresist is etched is extremely low, and the above-described problem is suppressed. be able to.

As described above, when the method of manufacturing a semiconductor device according to the first embodiment is used, an etching process in which the resist etching rate and the resist selectivity are stable can be performed from the first silicon substrate. Therefore, the problem that the insulating film immediately below the photoresist is etched to increase the dimension of the contact hole and the problem that the diffusion layer at the bottom of the contact hole is etched can be solved. Therefore, occurrence of defective products can be suppressed as compared with the related art.

Second Embodiment Next, a method of manufacturing a semiconductor device according to a second embodiment of the present invention will be described step by step with reference to FIG. FIG. 4 is a diagram illustrating an example of a method for manufacturing a semiconductor device according to the second embodiment of the present invention. Note that the semiconductor manufacturing apparatus shown in FIG. 1 is also used in the implementation of the manufacturing method shown in FIG. 4, and also in the present embodiment, the components shown in FIG. Explain.

As shown in FIG. 4, first, a silicon substrate serving as a dummy is carried into the reaction chamber 6 (step S1).
1). A silicon substrate serving as a dummy is arranged on the lower electrode 3 and held by a silicon ring 11. The dummy silicon substrate loaded in step S11 is
This is different from the silicon substrate carried in at step S2 in FIG. 2 and is not a product. Examples of such a dummy silicon substrate include a silicon substrate provided with an insulating film on its surface but not patterned by a photoresist, or a silicon substrate that has already become defective.

Next, this silicon substrate serving as a dummy is
The fluorocarbon is placed in the reaction chamber 6 while being placed in the reaction chamber 6.
Generate a plasma mainly composed of carbon gas (step
S12). Specifically, a gas inlet 9 is provided in the reaction chamber 6.
C_TwoF₆/ O_TwoMixed gas or C_FiveF ₈/ Ar / O_TwoMixed gas
Into the coil 10
By applying high-frequency power from the
A zuma is generated (see FIG. 1). At the same time, the lower electrode 3
A DC voltage is applied by the
The high-frequency power supply 4
High-frequency power is applied to the lower electrode 3 by the
A high-frequency voltage is generated on a silicon substrate to be
reference). After discharging for a predetermined time, the high frequency power supply 2
The output from the frequency power supply 4 is turned off to extinguish the plasma.

Next, oxygen plasma is generated in the reaction chamber 6, and the polymer film formed by the generation of the plasma in step S12 is removed (step S13). Specifically, oxygen gas is introduced into the reaction chamber 6 from the gas inlet 9 and high frequency power is applied to the coil 10 by the high frequency power supply 2 to generate plasma (see FIG. 1). At the same time, similarly to the above, the dummy silicon substrate and the lower electrode 3 are electrostatically attracted, and a high-frequency voltage is generated on the dummy silicon substrate (see FIG. 1). As a result, oxygen ions are drawn in, and the polymer films adhered to the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 during the above step S12 are removed by the oxygen ions, and the inside of the reaction chamber 6 is removed. Will be cleaned. After that, the dummy silicon substrate is carried out of the reaction chamber 6 (Step S14).

Next, whether the surface temperature of the portion of the reaction chamber 6 facing the plasma, that is, in the example of FIG. 1, the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 has been saturated. A determination is made (step S15). As a result of the determination, when the surface temperature is not saturated, the dummy silicon substrate is replaced with another dummy silicon substrate, and the above steps S11 to S15 are repeated.

On the other hand, if the result of determination is that the surface temperature is saturated, the silicon substrate 5 on which the insulating film has been patterned is carried into the reaction chamber 6 (step S16). This silicon substrate 5 is the same as that used in step S2 in FIG. 2, and is a product.

In the present embodiment, the method for determining whether the surface temperature is saturated is not particularly limited. For example, a determination can be made by arranging a temperature sensor in the reaction chamber and monitoring a signal from the sensor. In addition, the number of repetitions is previously set to 1, 2, 3, 4,
, And steps S16 to S1 to be described later.
9 to find the minimum number of times in which no defective product has occurred, and make a determination based on this number.

In addition, as a judgment method, a point at which the C / F becomes constant by observing the light emission intensity by the emission analysis method and judging that the C / F is saturated at this time, or a method of judging that the saturation occurs at Vpp (the lower electrode The peak-to-peak value of the voltage applied to No. 3 is determined to be saturated when the voltage becomes constant.

Next, plasma containing fluorocarbon as a main component is generated in the reaction chamber 6, thereby etching the insulating film of the silicon substrate 5 (step S17). This step is performed by introducing a fluorocarbon gas from the gas inlet 9 and activating the high-frequency power supply 2, the DC power supply 17, and the high-frequency power supply 4 in the same manner as in step S12 and step S3 shown in FIG. 1). Through this step, a contact hole is formed in the insulating film of the silicon substrate 5.

Next, oxygen plasma is generated in the reaction chamber 6, and the polymer film formed by the generation of the plasma in step S17 is removed (step S18). This step is performed by introducing oxygen gas from the gas inlet 9 and activating the high-frequency power supply 2, the DC power supply 17, and the high-frequency power supply 4 in the same manner as in step 1S3 and step S4 shown in FIG. 2 (FIG. 1). reference). In this step, the polymer film adhered to the bottom of the contact hole and the polymer film adhered to the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 are removed, and the inside of the reaction chamber 6 is cleaned.

Finally, the silicon substrate 5 having the contact holes formed therein is carried out of the reaction chamber 6 (step S1).
9). When processing the silicon substrate 5 continuously, steps S16 to S19 may be repeated.

As described above, in the method of manufacturing a semiconductor device according to the present embodiment, similarly to the first embodiment, the surface temperature in the portion of the reaction chamber 6 facing the plasma is saturated, and then the patterning is performed. A contact hole is formed in the insulating film of the silicon substrate. for that reason,
Even for the first sheet, the same stable resist etching rate and resist selectivity as shown in FIG. 3 are obtained, and the etching characteristics are stable. Therefore, the problem that the size of the contact hole is enlarged by etching the insulating film immediately below the photoresist and the problem that the diffusion layer at the bottom of the contact hole is etched can be solved. Generation can be suppressed.

Also in this embodiment, a silicon substrate which cannot be made into a product occurs as in the prior art. However, this silicon substrate is already a defective product, or patterning is performed on this silicon substrate. Since there is no need to perform this, it is possible to reduce costs as compared with the related art. Also in the present embodiment, the patterned silicon substrate can be prevented from being wasted similarly to the first embodiment.

Third Embodiment Next, a method of manufacturing a semiconductor device according to a third embodiment of the present invention will be described step by step with reference to FIG. FIG. 5 is a diagram illustrating an example of a method for manufacturing a semiconductor device according to the third embodiment of the present invention. Note that the semiconductor manufacturing apparatus shown in FIG. 1 is also used in the implementation of the manufacturing method shown in FIG. 5, and also in the present embodiment, the components shown in FIG. Explain.

As shown in FIG. 5, first, a silicon substrate serving as a dummy is loaded into the reaction chamber 6 (step S2).
1). Next, the dummy silicon substrate is placed in the reaction chamber 6.
Is generated in the reaction chamber 6 in the state where the main component is a fluorocarbon gas (step S2).
2). After extinguishing this plasma, oxygen plasma is further generated in the reaction chamber 6, and the polymer film formed by the generation of the plasma in step S22 is removed (step S23). Steps S21 to S23 are performed in the same manner as steps S11 to S13 shown in FIG.

Next, in a state where the silicon substrate serving as the dummy is set in the reaction chamber 6, step S shown in FIG.
It is determined whether or not the surface temperature of the portion of the reaction chamber 6 facing the plasma in the reaction chamber 6 is saturated (step S2).
4). As a result of the judgment, if the surface temperature is not saturated,
Steps S22 to S24 are repeated.

In the present embodiment, unlike the second embodiment, the plasma generation steps (steps S22 and S23) are repeated without replacing the dummy silicon substrate until the surface temperature is saturated. Also, the processing time required for step S22 and step S23 in the present embodiment and the processing time in step S1 in the second embodiment
The processing time required for step 2 and step 13 is the same.
Therefore, in this embodiment, compared to the second embodiment, the cost can be reduced by an amount corresponding to one dummy silicon substrate.

On the other hand, as a result of the determination, if the surface temperature is saturated, the dummy silicon substrate is carried out of the reaction chamber 6 (step S25), and the silicon substrate 5 on which the insulating film has been patterned is removed from the reaction chamber. 6 (step S26). This silicon substrate 5 corresponds to Step S2 in FIG.
And the product. The determination whether the surface temperature is saturated,
This is performed using the method described in the second embodiment.

Next, plasma containing fluorocarbon as a main component is generated in the reaction chamber 6, thereby etching the insulating film of the silicon substrate 5 (step S27). Through this step, a contact hole is formed in the insulating film of the silicon substrate 5. Further, oxygen plasma is generated in the reaction chamber 6, and the polymer film formed by the generation of the plasma in step S7 is removed (step S28). In this step, the polymer film adhered to the bottom of the contact hole and the polymer film adhered to the lower surface of the upper electrode 1, the inner surface of the quartz dome 12, and the upper surface of the silicon ring 11 are removed, and the inside of the reaction chamber 6 is cleaned.

Finally, the silicon substrate 5 having the contact hole formed therein is carried out of the reaction chamber 6 (step S2).
9). When processing the silicon substrate 5 continuously, steps S26 to S29 may be repeated.
Steps S26 to S29 are performed in the same manner as steps S16 to S19 shown in FIG.

As described above, in the method of manufacturing a semiconductor device according to the present embodiment, as in the first and second embodiments, the surface temperature in the portion of the reaction chamber 6 facing the plasma is saturated before the pattern is formed. A contact hole is formed in the insulated insulating film of the silicon substrate. Therefore, even if it is the first sheet, the same stable resist etching rate and resist selectivity as shown in FIG. 3 are obtained, and the etching characteristics are stable. Therefore,
The problem that the size of the contact hole is enlarged due to the etching of the insulating film directly under the photoresist and the problem that the diffusion layer at the bottom of the contact hole is etched can be eliminated. Can be suppressed.

Also in this embodiment, a silicon substrate which cannot be made into a product occurs in the same manner as in the prior art, but this silicon substrate is already defective or this silicon substrate is subjected to patterning. Since there is no need, cost can be reduced as compared with the related art. Also in the present embodiment, it is possible to prevent the patterned silicon substrate from being wasted similarly to the first and second embodiments.

In the second and third embodiments, the silicon substrate serving as a dummy at the time of the first plasma generation is set in the reaction chamber 6 because the plasma containing fluorocarbon gas as a main component is used. This is because it is being generated. That is, unless a silicon substrate is placed on the lower electrode 3, a polymer film is formed on the upper surface of the lower electrode 3.

On the other hand, in the first embodiment, the plasma of the argon gas and the oxygen gas is generated, and the polymer film is not formed. Therefore, it is not necessary to arrange a dummy silicon substrate on the lower electrode 3. However, the lower electrode 3 is usually formed of a material containing a metal such as aluminum. Therefore, from the viewpoint of preventing metal contamination in the reaction chamber, it is a preferable embodiment to arrange the dummy silicon substrate and generate the plasma as in the second and third embodiments.

[0067]

As described above, by using the method of manufacturing a semiconductor device according to the present invention, it is possible to suppress the silicon substrate processed in particular from the start until a certain time has passed from becoming defective. Therefore, the cost of the semiconductor device can be reduced as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a semiconductor manufacturing apparatus used in a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a method of manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an effect of the method for manufacturing a semiconductor device according to the first embodiment of the present invention;

FIG. 4 is a diagram illustrating an example of a method of manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of a method of manufacturing a semiconductor device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper electrode 2 High frequency power supply 3 Lower electrode 4 High frequency power supply 5 Silicon substrate 6 Reaction chamber 7 Turbo molecular pump 8 Dry pump 9 Gas inlet 10 Coil 11 Silicon ring 12 Quartz dome 13 Heater 14 Heater 15 Heater power supply 16 Heater power supply 17 DC power supply

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M104 AA01 DD08 DD19 DD22 GG13 HH00 HH14 HH15 5F004 AA01 BA09 BA20 BB11 BB18 BB23 BB26 CA01 CA04 DA00 DA02 DA03 DA15 DA16 DA23 DA26 DB06 EB01 5F033 QQ09 QQ12 QQ15 Q89 XX09 XX34

Claims (9)

[Claims] 1. A method for manufacturing a semiconductor device, wherein a contact hole is formed in an insulating film formed on a silicon substrate using a semiconductor manufacturing apparatus having a reaction chamber for generating plasma, wherein the contact hole is formed in the insulating film. Forming a plasma comprising an argon gas and an oxygen gas in the reaction chamber for a predetermined time before forming the semiconductor device. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the generation of the plasma is performed until a surface temperature in a portion of the reaction chamber facing the plasma is saturated. 3. A method of manufacturing a semiconductor device, wherein a contact hole is formed in an insulating film formed on a silicon substrate by using a semiconductor manufacturing apparatus having a reaction chamber for generating plasma. Before forming (1)
A step of generating plasma containing a fluorocarbon gas as a main component in the reaction chamber in a state where a silicon substrate serving as a dummy is disposed in the reaction chamber; and (2) forming a polymer film formed by the plasma in the reaction chamber. Generating a plasma to remove the plasma, thereby saturating a surface temperature in a portion of the reaction chamber facing the plasma. 4. The method according to claim 1, wherein the step (1) and the step (2) are repeated a plurality of times, and each time the step is repeated, the dummy silicon substrate is replaced with another dummy silicon substrate. 4. The method for manufacturing a semiconductor device according to item 3. 5. The method according to claim 3, wherein the steps (1) and (2) are repeated without replacing the dummy silicon substrate. 6. The semiconductor according to claim 1, wherein the formation of the contact hole in the patterned insulating film of the silicon substrate is performed by generating plasma containing fluorocarbon as a main component in the reaction chamber. Device manufacturing method. 7. The method according to claim 7, wherein the fluorocarbon gas is CH ₂ F ₂
Gas, CH ₃ F gas, C ₂ F ₆ gas, C ₃ F ₈ gas, C ₄ F ₆
7. A gas containing at least one gas selected from a gas, a C ₄ F ₈ gas and a C ₅ F ₈ gas.
13. The method for manufacturing a semiconductor device according to item 5. 8. The semiconductor manufacturing apparatus according to claim 1, further comprising a high-frequency power supply for generating plasma and a power supply for applying a DC voltage to the silicon substrate, and having a function of independently controlling each power supply. Item 4. The method for manufacturing a semiconductor device according to item 1 or 3. 9. The semiconductor manufacturing apparatus according to claim 1, wherein at least one selected from a capacitively coupled plasma generator, a dual-frequency capacitively coupled plasma generator, an inductively coupled plasma generator, a microwave plasma generator, and a VHF plasma generator is provided. 4. The method according to claim 1, wherein the source is provided as a source.
13. The method for manufacturing a semiconductor device according to item 5.