JP2001284320A - Dry etching method and method of manufacturing semiconductor dynamic quantity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the uniformity of an etching rate in a wafer face, when the oxidized film of a wafer is subjected to dry-etching. SOLUTION: A process for arranging an SOI substrate 20 on a lower electrode 3 in a processing chamber 2, introducing etching gas into the processing chamber 2, and dry etching an insulating film by applying high-frequency power to the lower electrode 3 and a destaticization process for discharging charges charged on the SOI substrate 20 at the time of dry etching, are repeated alternately and the insulating film is removed. Even if the SOI substrate 20 is charged up at dry etching by repeating the directing process and the destanticization process, the charges charged on the SOI substrate 20 cannot be discharged by the destanticization process. Thus, charging up of distribution in a substrate face can be eliminated. Consequently, the dispersion of ion incident quantity in the substrate face is eliminated, and the uniformity of etching rate can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching method and a method for manufacturing a semiconductor dynamic quantity sensor by dry etching, and is particularly suitable for a semiconductor acceleration sensor and a semiconductor angular velocity sensor.

[0002]

2. Description of the Related Art In recent years, an SOI substrate is increasingly used for manufacturing a semiconductor sensor. This is because the buried oxide film of the SOI substrate can be used as a sacrificial layer for etching removal in the process of forming a fine structure (sensing portion) including a movable electrode, a fixed electrode, and the like.

Conventionally, wet etching using hydrofluoric acid or the like has been mainly used for removing an oxide film from an SOI substrate. However, according to wet etching, a so-called structure in which structures adhere to each other due to surface tension of a liquid. The sticking (sticking) phenomenon is likely to occur.

In order to avoid occurrence of the sticking phenomenon, dry etching using plasma has recently been used for removing an oxide film on an SOI substrate.

[0005]

However, when the oxide film on the SOI substrate is removed by dry etching,
There has been a problem that the etching rate becomes non-uniform in the wafer surface. As a result of the experiment, when the oxide film of the SOI substrate was dry-etched, a result that the etching rate was lower at the center of the wafer than at the outer edge of the wafer was obtained as shown in FIG.

When such an uneven etching rate occurs, the silicon is etched even if the etching selectivity between the silicon and the oxide film is sufficiently set, so that the structure is partially over-etched and the movable electrode is over-etched. The distance between the movable electrode and the fixed electrode varies, and the capacitance determined by the distance between the movable electrode and the fixed electrode changes from the design position.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to improve the uniformity of an etching rate in a wafer surface when removing an oxide film from a wafer by dry etching.

[0008]

The present inventors considered that the charge accumulated in the wafer was involved in making the etching rate non-uniform, and examined the charge accumulated during dry etching. .

FIG. 8 is a schematic diagram of a dry etching apparatus. Hereinafter, the dry etching method will be described with reference to FIG.

First, the SOI substrate 100 on which dry etching is performed, that is, the active layer 100a is selectively etched to form a structure including a movable electrode and a fixed electrode, and the support layer 100b is selectively etched. An SOI substrate 100 having an opening 100d reaching the oxide film 100c is prepared.

The SOI substrate 100 is placed in a counterbore formed on a quartz plate 101. At this time, the support layer 100b
The side faces the upper electrode 102 side. Then, an etching gas is introduced into the apparatus, and the lower electrode 103 is formed.
A high frequency power is applied from a high frequency power supply (RF power supply) 104 to generate a plasma 105. Thereby, the etching gas is decomposed into ions and radicals (active species), and the oxide film 100c is dry-etched. And FIG.
As shown in (1), while supplying a constant amount of etching gas, the RF power of the high-frequency power source 104 is kept constant (here, 2.5 kW), and dry etching is continued.

Although dry etching is performed by such a method, when the SOI substrate 100 is etched, since the active layer 100a and the support layer 100b are insulated by the oxide film 100c, the electric charge accumulated in the SOI substrate 100 is reduced. Is difficult to escape, and is easy to charge up.

Further, in a fine structure such as an acceleration sensor or an angular velocity sensor, insulation is separated by a trench 100e in order to form a capacitor by insulating a movable electrode and a fixed electrode from each other. Insulated.

For this reason, an equivalent circuit of the dry etching apparatus of FIG. 8 is shown by the circuit configuration of FIG. That is, the so-called sheath 106, which forms the boundary between the plasma 105 and the SOI substrate 100, is a parallel circuit of the capacitor C1 and the diode D1, and the oxide film 100c.
Is the capacitor C2, and the trench 100e is the capacitor C3.
Is obtained.

With such a circuit configuration, when the capacitance of the trench 100e (the capacitor C3 equivalent to the trench 100e) is charged up, the SOI substrate 10
0, a distribution occurs in the in-plane charge-up, and the plasma 10
The incident amount of the ions decomposed by the SOI substrate 5
It is considered that there is variation in the plane of 0 and the etch rate uniformity is deteriorated. For this reason, as shown in FIG.
When the oxide film 100c of the I-substrate 100 is dry-etched, it is considered that the etching rate is lower at the center of the wafer than at the outer edge of the wafer.

Therefore, according to the first aspect of the present invention, the insulating film (20c) is provided on one electrode (3) in the processing chamber (2) provided with the parallel plate electrodes (3, 4). In a dry etching method for removing an insulating film by disposing a substrate (20), introducing an etching gas into the processing chamber, and applying high-frequency power to the flat electrode, the etching gas is introduced into the processing chamber while removing the insulating film. Including a process of controlling the high-frequency power and dry-etching the insulating film, and a charge removing process of discharging charges charged on the substrate during the dry etching, the insulating film is removed by repeatedly performing the dry etching and the charge removing process alternately. It is characterized by doing.

As described above, by repeatedly performing the dry etching step and the charge removing step, even if the substrate is charged up during the dry etching, it is possible to discharge the electric charge charged to the substrate by the charge removing step. Can eliminate the charge-up distribution.
This eliminates variations in the amount of ions incident on the substrate surface, and improves the uniformity of the etching rate.

According to a second aspect of the present invention, in the charge removing step, the introduction of the etching gas introduced into the processing chamber during the dry etching step is stopped.

If the gas used for etching causes both etching and deposition, deposition occurs at the time of static elimination, and etching may not proceed in the next dry etching step. For this reason, by stopping the introduction of the etching gas, it is possible to prevent deposition from occurring at the time of static elimination. in this case,
Instead of the etching gas, an inert gas such as Ar may be introduced.

According to a third aspect of the present invention, when the dry etching step and the charge removing step are performed once each as one cycle, the dry etching step is performed for 8 minutes or less per cycle. .

As described above, by setting the time of the dry etching process per cycle to 8 minutes or less, the capacity in the substrate is charged up by the dry etching for a long time, and the uniformity of the etching rate is lost. Dry etching can be prevented.

The invention according to claim 4 is characterized in that, when the dry etching step and the charge removing step are performed once each as one cycle, the charge removing step is performed for 10 seconds or more per cycle.

As described above, by setting the time of the charge removing step per cycle to 10 seconds or more, the charge charged on the substrate can be sufficiently released.

According to the fifth aspect of the present invention, a substrate in which an insulating film (20c) is provided on one electrode (3) in a processing chamber (2) provided with parallel plate electrodes (3, 4). (2
In the dry etching method of removing the insulating film by disposing an etching gas into the processing chamber and applying high-frequency power to the flat plate electrode, a charge removal step of discharging charges charged on the substrate during the dry etching is performed. And the charge removal step is performed during dry etching.

As described above, if the charge removing step is performed during the dry etching, the etching continues during the charge removing step even if the etching rate is sacrificed.
The same effect as the first aspect is obtained, and the dry etching time can be shortened.

For example, in the static elimination step, an etching gas is continuously introduced into the processing chamber, and
By changing the magnitude of the high-frequency power during the period during which the dry etching is being performed and during the period during which the neutralization step is not performed, the neutralization operation in which the electric charge charged to the substrate is released while the dry etching is continued. Can be played.

In the invention according to claim 7, the charge removing step is performed a plurality of times during the dry etching, and one time for each time.
This is performed for a time of 0 second or more, and the same effect as that of claim 4 can be obtained.

According to an eighth aspect of the present invention, the charge removing step is performed a plurality of times during dry etching, and the charge removing step is repeated every eight minutes or less. Obtainable.

According to a ninth aspect of the present invention, in the dry etching step, the high frequency power is controlled to a size for dry etching, and in the charge removing step, the high frequency power is controlled to be lower than that in the dry etching. I have. For example, as described in claim 10, in the static elimination step,
The high frequency power is reduced to 1/5 to 1/50 of that during dry etching.

As described above, in the charge removing step, the electric charge charged on the substrate can be released by controlling the high frequency power to be lower than that in the dry etching.

In the eleventh aspect, even if the gas pressure in the processing chamber is higher than the gas pressure in the processing chamber in the dry etching step, the electric charge charged on the substrate is released. Can be.

According to the dry etching method described in claims 11 and 12, the insulating film (20
c) preparing an SOI substrate (20) having an active layer (20a) disposed on one side and a support layer (20b) disposed on the other side, and selectively etching the active layer; Forming a trench having a movable electrode and a fixed electrode for measuring a physical quantity, and selectively etching a support layer to form an opening reaching an insulating film. Forming a 20d), dry etching the insulating film and releasing the structure,
In a method of manufacturing a semiconductor physical quantity sensor comprising
It is preferable to apply the present invention to dry etching of an insulating film.

Note that the reference numerals in parentheses of the above means indicate the correspondence with specific means described in the embodiments described later.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention shown in the drawings will be described below.

FIG. 1 shows a cross-sectional structure of an etching apparatus 1 used for performing a dry etching method. FIG.
2 shows a cross-sectional configuration of the SOI substrate 20 to be subjected to dry etching.

The SOI substrate 20 shown in FIG. 2 is in the process of manufacturing a semiconductor dynamic quantity sensor (for example, a semiconductor acceleration sensor or a semiconductor angular velocity sensor). That is, this S
The OI substrate 20 includes a step of forming a structure including a movable electrode and a fixed electrode in the active layer 20a, and an opening reaching the oxide film (insulating film) 20c in the support layer 20b. 20d is formed. For example, a structure is formed by selectively etching the active layer 20a and forming a trench 20e reaching the oxide film 20c.
Is selectively etched using a KOH aqueous solution or the like to form an opening 20d reaching the oxide film 20c. The oxide film 20c of the SOI substrate 20 having such a structure is dry-etched by the etching apparatus 1 shown in FIG.

As shown in FIG. 1, this etching apparatus 1
Is provided with a processing chamber 2. Dry etching is performed in the processing chamber 2. The processing chamber 2 includes a parallel plate electrode including a lower electrode 3 on which an SOI substrate 20 to be subjected to dry etching is disposed, and an upper electrode (counter electrode) 4 disposed to face the lower electrode 3. I have.

The lower electrode 3 is provided with a quartz plate 3a, and a counterbore 3b formed on the quartz plate 3a
An I substrate 20 is provided. For example, 13.56 MHz high frequency power (RF power) can be applied to the lower electrode 3 from the high frequency power supply 5. The upper electrode 4 has a plurality of gas supply holes 4a arranged at equal intervals,
It is arranged in parallel with the lower electrode 3 so that the reaction gas can flow in a shower shape. These lower electrode 3 and upper electrode 4 can be cooled by cooling water (not shown).

The etching apparatus 1 is provided with a gas inlet 6 for supplying various gases. The gas inlet 6 is disposed above the upper electrode 4, and various gases supplied from the gas inlet 6 are supplied to the gas supply holes 4 of the upper electrode 4.
a into the processing chamber 2.

The gas inlet 6 is connected to a gas inlet pipe 7 provided with a valve 7a. In the gas introduction pipe 7,
A plurality (three in this embodiment) of gas introduction pipes 8a, 9a, 10a connected to supply sources 8, 9, 10 of various gases are connected. In the present embodiment, each gas introduction pipe 8a,
CHF ₃ gas, CF ₄ gas, and Ar gas are supplied from 9a and 10a, respectively. Each of the gas introduction pipes 8a, 9a, and 10a has a gas introduction pipe 8a.
Valves 8b, 9b, 10 for opening and closing a, 9a, 10a
b, and mass flow controllers 8c, 9c, 10c for adjusting the gas flow rate.

On the other hand, an exhaust pipe 11 is connected to a lower portion of the processing chamber 2. Through the exhaust pipe 11, the inside of the processing chamber 2 can be depressurized by evacuation means 12 such as a vacuum pump. With such a configuration, for example, several 1.33 Pa to 133 Pa (10 mTorr to 10 mPa) in the processing chamber 2 while the gas is supplied from the gas supply sources 8, 9, and 10.
The degree of vacuum can be maintained at about 1 Torr).

Using the etching apparatus configured as described above, dry etching is performed as follows. FIG.
2 shows a timing chart of the dry etching, and the details of the dry etching will be described with reference to FIG.

Dry etching is performed by repeating the dry etching step and the charge removing step.
In other words, the charge removing step is performed during the dry etching.

[Dry Etching Step] Here, dry etching is performed by reactive ion etching. First, all the valves 8 b to 10 b are opened, and a mixed gas of CHF ₃ / CF ₄ / Ar is introduced into the processing chamber 2. At this time, the mass flow controllers 8c to 10c
c, the flow rate of each gas is controlled, and CHF ₃ is 100 s.
ccm, CF ₄ are set to 5 ccm, and Ar is set to 100 sccm. In addition, the gas pressure in the processing chamber 2 is set to 1.33 Pa (100 mTorr) by the evacuation unit 12.

Then, for example, 13.5
A high frequency power of 6 MHz is applied to the lower electrode 3 so that the RF power becomes, for example, 2.5 kW. This allows
Plasma is generated between the upper electrode 4 and the lower electrode 3, various gases are decomposed into ions and radicals by the plasma, and the oxide film 20 c of the SOI substrate 20 is dry-etched. Such a dry etching step is performed, for example, for 3 minutes.

At the time of this dry etching, as described above, the capacitance due to the trench 20e formed in the SOI substrate 20 is charged up (charge is stored).

Next, the valves 8b and 9b are closed, and the supply gas is switched to only Ar. The flow rate of Ar gas is set to, for example, 200 sccm by the mass flow controller 10c, and the gas pressure in the processing chamber 2 is set to 1.33 Pa by the evacuation unit 12.
(100 mTorr).

Then, the RF power from the high frequency power supply 5 is reduced to, for example, 100 W. Thereby, the trench 2
e, the charge stored in the SOI substrate 20 including the charge stored in the capacitance is released into the conductive plasma,
The capacitance due to the trench 20e is eliminated. Such a neutralization step is performed, for example, for 5 minutes.

The reason why the gas type is changed to only the inert gas Ar as described above is that when the gas used for etching causes both etching and deposition, it is only necessary to lower the RF power alone. This is because deposition may occur at the time of static elimination, and etching may not proceed in the next etching step.

In the charge removal step, the charge removal operation can be achieved by lowering the RF power from the high-frequency power supply 5 than during dry etching. It is good to lower to 50.

Thereafter, the dry etching step shown by the mark and the charge removal step shown by the mark are alternately repeated a plurality of times to obtain the SOI
Dry etching is performed until the oxide film 20c is removed while discharging the electric charge charged on the substrate 20 into the conductive plasma. Thus, the structure including the movable electrode and the fixed electrode formed on the active layer 20a is released, and the semiconductor physical quantity sensor is manufactured.

As described above, by alternately performing the etching step and the charge removing step, the uniformity of the etching rate in the surface of the SOI substrate 20 can be improved, and dry etching with a very small variation in the etching rate can be performed. Therefore, the distance between the movable electrode and the fixed electrode becomes uniform, and a semiconductor dynamic quantity sensor having good characteristics can be manufactured.

When the uniformity of the etching rate when etching was performed by such a method was measured, the result shown in FIG. 4 was obtained. As is clear from these results,
By repeating the dry etching process and the charge removal process,
Compared with the case where dry etching is continuously repeated (conventional method), the uniformity of the etching rate can be greatly improved.

Further, as a comparative experiment, an experiment in which the discharge was stopped for a time corresponding to the static elimination time (however, in this case,
(No charge removal was performed), but the etching rate did not change compared to the case where dry etching was continuously performed. From this, it is understood that the uniformity of the etching rate in the plane of the SOI substrate 20 can be improved by performing the charge removing step.

In addition, the case where each of the dry etching step and the charge removal step is performed once is regarded as one cycle, and the relationship between the charge removal time per cycle and the uniformity of the etching rate, and the etching time per cycle and the etching rate. The relationship with uniformity was investigated. The results are shown in FIGS. 5 and 6, respectively. However, the relationship between the etching time and the uniformity of the etching rate was examined when the static elimination time was fixed at 1 minute.

First, as is apparent from the results of FIG. 5, the case where the static elimination step is not performed (the static elimination time is 0 minute) is as follows.
It can be seen that the uniformity of the etching rate is higher when the charge removing step is performed even for a short time, and the uniformity of the etching rate is particularly improved when the charge removing time is 10 seconds or more.

On the other hand, looking at the results in FIG. 6, it can be seen that the etching rate uniformity is good until the etching time is about 8 minutes, but it rapidly deteriorates after 9 minutes. This is because if the etching time becomes longer, the capacity of the trench 20e is charged up before that, and the uniformity of the etching rate is impaired.

From these results, it is desirable that the charge removal time per cycle be 10 seconds or more and the dry etching time per cycle be 8 minutes or less.

As described above, by repeating the etching and the charge elimination at appropriate time cycles, the uniformity of the etch rate can be further improved, and the buried oxide film of the SOI substrate 20 can be removed.

(Second Embodiment) In the first embodiment,
Although the dry etching step is stopped when performing the charge removing step, the charge removing step may be performed while the dry etching step is continued. That is, the dry etching step may be performed under the condition where the charge removal operation is performed.

For example, after performing the dry etching process shown in the first embodiment for 3 minutes, the gas composition, the gas flow rate and the gas pressure are kept as they are, and the R
Since the ion energy can be reduced by reducing only the F power from 2500 W to 100 W,
Dry etching having a charge eliminating function can be performed.

When such a method is used, the etching proceeds continuously even if the etching rate is sacrificed during the charge removal step. Therefore, the total time of the dry etching process should be shorter than that of the first embodiment. Can be.
Therefore, the same effect as that of the first embodiment can be obtained, and the dry etching can be shortened.

In this case as well, the charge-up process can be sufficiently removed by performing the charge removing step a plurality of times during the dry etching and performing the processing for 10 seconds or more each time. Further, if the charge removal step is performed a plurality of times and is repeated every eight minutes or less, it is possible to prevent dry etching from being performed while the SOI substrate 20 is charged up.

(Other Embodiments) In the second embodiment,
As a method of reducing the ion energy, the RF power of the high-frequency power supply 5 is reduced. However, it is also possible to increase the gas pressure in the processing chamber 2 from the time of dry etching. For example, when the gas pressure during dry etching is 2
The above effect can be obtained by increasing the value from 00% to 500%.
In the case of the above embodiment, the dry etching condition may be increased from 1.33 Pa (0.1 Torr) to, for example, 6.65 Pa (0.5 Torr).

In each of the above embodiments, the case where the SOI substrate 20 is used as the wafer has been described. However, the wafer to be used is not limited to the SOI substrate 20. For example, when performing dry etching of an insulating substrate or the like, if the etching rate uniformity is deteriorated due to charge-up of the wafer, the dry etching method described in each of the above embodiments should be applied in any case. Thereby, the same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a sectional configuration of an etching apparatus used for performing dry etching according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a cross-sectional configuration of an SOI substrate 20 to be subjected to dry etching.

FIG. 3 is a diagram showing a timing chart of dry etching.

FIG. 4 is a diagram showing a measurement result of etching rate uniformity showing an effect when a charge removing step is introduced.

FIG. 5 is a diagram showing a relationship between a charge removal time per cycle and etching rate uniformity.

FIG. 6 is a diagram showing a relationship between etching time per cycle and etching rate uniformity.

FIG. 7 is a diagram showing a variation of an etching rate in a wafer surface obtained by an experiment.

FIG. 8 is a diagram schematically showing conventional dry etching.

FIG. 9 is a diagram showing a time chart of a conventional dry etching.

10 is a diagram showing a state when the dry etching shown in FIG. 8 is performed by an equivalent circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Etching apparatus, 2 ... Processing chamber, 3 ... Lower electrode, 4 ...
Upper electrode, 5 ... High frequency power supply, 6 ... Gas inlet, 7 ... Gas inlet pipe, 7a ... Valve, 8-10 ... Gas supply source, 8A
-10a ... gas introduction pipe, 8b-10b ... valve, 8c ~
10c: mass flow controller, 11: exhaust pipe, 12
... Vacuum evacuation means, 20 ... SOI substrate, 20a ... Active layer,
20b: support layer, 20c: oxide film, 20d: opening, 2
0e ... trench.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Muneo Yorinaga, 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Prefecture Inside Japan Automotive Parts Research Institute (72) Inventor, Takeshi Fukada 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture (72) Inventor Hiroki Noguchi 1-1-1, Showa-cho, Kariya-shi, Aichi F-term (reference) 5F004 AA01 BA04 BB13 BC03 CA01 CA02 CA03 DA01 DA16 DA23 DB03

Claims (13)

[Claims] 1. An insulating film (20c) on one electrode (3) in a processing chamber (2) provided with parallel plate electrodes (3, 4).
A dry etching method for removing the insulating film by disposing a substrate (20) provided with, applying an etching gas into the processing chamber, and applying high-frequency power to the electrode; Controlling the high-frequency power while introducing an etching gas into the chamber, and dry-etching the insulating film; and a charge removing step of discharging charges charged to the substrate during the dry etching. A dry etching method, wherein the insulating film is removed by alternately and repeatedly performing a charge removing step. 2. The dry etching method according to claim 1, wherein in the charge removing step, the introduction of the etching gas introduced into the processing chamber at the time of the dry etching step is stopped. 3. The method according to claim 1, wherein the case where the dry etching step and the charge removing step are performed once each is one cycle, and the dry etching step is performed for 8 minutes or less per cycle. 3. The dry etching method according to 1. 4. The method according to claim 1, wherein the cycle of performing the dry etching step and the neutralization step once is one cycle, and the neutralization step is performed for 10 seconds or more per cycle. The dry etching method according to any one of the above. 5. An insulating film (20c) on one electrode (3) in a processing chamber (2) provided with parallel plate electrodes (3, 4).
A dry etching method for removing the insulating film by disposing a substrate (20) provided with, applying an etching gas into the processing chamber, and applying high-frequency power to the plate electrode; A charge removing step of discharging charges charged on the substrate, wherein the charge removing step is performed during the dry etching. 6. In the static elimination step, the magnitude of the high-frequency power is larger than a period during which the etching gas is continuously introduced into the processing chamber and a period during which the dry etching is not performed. The dry etching method according to claim 5, wherein by changing the thickness, a charge removal operation is performed in which charges charged to the substrate are released while the dry etching is continued. 7. The dry etching method according to claim 5, wherein the charge removing step is performed a plurality of times during the dry etching, and is performed for 10 seconds or more each time. 8. The method according to claim 5, wherein the charge removing step is performed a plurality of times during the dry etching, and the charge removing step is repeated every eight minutes or less. Dry etching method. 9. The high frequency power is controlled to a size for dry etching in the dry etching step, and the high frequency power is controlled to be lower than in the dry etching in the charge removing step. 1 to 8
Dry etching method. 10. The dry etching method according to claim 9, wherein in the charge removing step, the high-frequency power is reduced to 1/5 to 1/50 of the dry etching. 11. The method according to claim 1, wherein a gas pressure in the processing chamber is higher than a gas pressure in the processing chamber in the dry etching step in the charge removing step. The dry etching method described. 12. The dry etching step according to claim 1, wherein the dry etching is performed by reactive ion etching.
The dry etching method described in (1). 13. An SOI substrate (20) having an active layer (20a) disposed on one side of an insulating film (20c) and a support layer (20b) disposed on the other side is provided. Selectively etching the active layer to form a trench (20e) to form a structure having a movable electrode and a fixed electrode for measuring a physical quantity; and selectively etching the support layer. A step of forming an opening (20d) reaching the insulating film; and a step of dry-etching the insulating film to release the structure. 13. A method for manufacturing a semiconductor physical quantity sensor, wherein the dry etching method according to claim 1 is applied when dry-etching an insulating film.