JP2002113700A - Micromachine manufacturing device, manufacturing method for micromachine, manufacturing method for diffraction grating light valve and manufacturing method for display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve etching uniformity and prevent delay of etching reaction due to natural oxide film generated on a polysilicon surface in etching of polysilicon using XeF2 gas. SOLUTION: This device is provided with a processing chamber 11 for etching a substrate 91, a microwave generator 21 feeding etching gas excited by microwave into the processing chamber 11, and a gas feeder 31 feeding xenon difluoride gas into the processing chamber 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micromachine manufacturing apparatus, a micromachine manufacturing method, a diffraction grating light valve manufacturing method, and a display device, and more particularly to a micromachine manufacturing for performing etching using xenon difluoride gas as an etching gas. The present invention relates to an apparatus, a method for manufacturing a micromachine, a method for manufacturing a diffraction grating light valve, and a display device using the diffraction grating light valve manufactured by the method.

[0002]

2. Description of the Related Art Surface micromachining technology based on a semiconductor integrated circuit manufacturing process for processing a thin film material on a silicon substrate is based on manufacturing a microstructure on a silicon substrate and bonding it to a semiconductor circuit. And a micromachine (MEMS) device.

At this time, in order to form a fine structure utilizing elasticity such as a beam, a space layer must be formed below the beam. Therefore, in order to form a fine structure, a method using a sacrificial layer is adopted. As the sacrificial layer, a silicon film or a polysilicon film having an excellent etching selectivity with respect to an oxide film, a nitride film, and a metal film is used. Xenon difluoride (Xe
By using F ₂ ) gas, low pressure CVD (hereinafter referred to as L
Denoted P-CVD, CVD means chemical vapor deposition,
A material such as a silicon nitride film, a thermal oxide film, aluminum, or titanium formed by the chemical vapor deposition (abbreviation for Chemical Vapor Deposition) method can have a selection ratio of 2000 or more. Therefore, it is a very effective process as a means for forming a micromachine element.

Further, in the etching with the XeF ₂ gas, there is no need to excite the etching gas using ordinary plasma, microwaves, or the like, and the etching can be performed with a raw gas. Therefore, it is only necessary to introduce the gas from the supply part of the XeF ₂ gas into the processing chamber, so that the etching apparatus has a very simple structure.

[0005]

[SUMMARY OF THE INVENTION However, when performing actual etching of polysilicon using XeF ₂ gas, by a natural oxide film which is formed on the polysilicon surface, a delay occurs in the etching reaction, etching There is a problem that the surface is not uniformly etched. This problem may be caused by the usual high frequency (R
In the case of etching using F) or a microwave, gas molecules are excited and have energy, and thus the natural oxide film is removed because the excited gas molecules sputter. On the other hand, in the etching using the XeF ₂ gas, since no energy is applied to the XeF ₂ molecules from the outside, there is no force to ion bombard the natural oxide film. Therefore, the natural oxide film cannot be sufficiently removed before etching the film to be etched.

For example, as shown in FIG. 9, a silicon oxide film 93 having a thickness of 0.3 μm is formed on a silicon substrate 92.
A polysilicon film 94 having a thickness of μm and a silicon nitride film 95 having a thickness of 100 nm are sequentially formed, and the silicon nitride film 95 has a length of 50 μm to 200 μm and a width of 0.5 μm.
A substrate 91 having a large number of openings 96 is prepared, and the polysilicon film 94 is etched with a XeF ₂ gas. At this time, the etching selectivity of the silicon nitride film 95 and the silicon oxide film 93 to the polysilicon film 94 is 10
Therefore, the silicon nitride film 95 serves as an etching mask, and the underlying silicon oxide film 93 serves as an etching stopper.

As a result, as shown in FIGS. 10 and 11,
The etching of the polysilicon film hardly progresses until the etching time reaches 6 minutes. In FIG. 10, a hatched portion indicates a region where the polysilicon film remains, and a white portion indicates a region where the etching of the polysilicon film is progressing. Further, as shown in FIG. 11, when the etching time is 6 minutes, only small holes are generated on the surface of the polysilicon film 94 as shown in FIG. Then, as shown in FIG. 3 (3), a situation where the etching starts to progress from such a small hole is also observed. It can be seen that the etching of the polysilicon film 94 progresses rapidly after the etching time exceeds 8 minutes. FIG. 10 shows the etching state of the polysilicon film 94 observed from above the silicon nitride film 95 side. FIG. 11 is an observation sketch of a cross section of the polysilicon film 94 in an etched state, and the cross section is hatched.

Next, the mechanism of the above phenomenon will be described with reference to FIG. As shown in FIG. 12, since the polysilicon film 94 is not etched using an etching gas excited by plasma or microwaves, a few nm formed on the surface of the polysilicon film 94 in the initial stage of etching. The natural oxide film 101 cannot break the natural oxide film 101 to etch the polysilicon film 94. Eventually, the XeF ₂ gas enters from the thin portion of the natural oxide film 101 and starts etching the polysilicon film 94. Therefore, the etching of the polysilicon film 94 proceeds at an early stage of the etching.

Thus, it can be seen that in the etching of the polysilicon film by the XeF ₂ gas, the etching of the polysilicon obviously does not depend on the etching time due to the presence of the natural oxide film on the surface of the polysilicon film.

Further, in the case of non-uniform etching using a natural oxide film, detection of the etching end point becomes important. However, as described above, since etching with XeF ₂ gas does not require RF or microwave, it is impossible to detect the conventional emission spectrum to determine the end point of etching.

[0011]

SUMMARY OF THE INVENTION The present invention provides a micromachine manufacturing apparatus, a micromachine manufacturing method, a diffraction grating light valve manufacturing method, and a display apparatus which have been made to solve the above problems.

A first micromachine manufacturing apparatus according to the present invention includes a processing chamber in which a substrate is etched, a microwave generator for supplying an etching gas excited by a microwave into the processing chamber, and a two-floor processing apparatus. Xenon (X
eF ₂ ) gas supply device for supplying gas.

In the first micromachine manufacturing apparatus,
Since the apparatus has a microwave generator that supplies an etching gas excited by microwaves into the processing chamber, the etching gas excited by microwaves is introduced into the processing chamber, and an oxide film formed on the surface of the substrate is provided. Can be removed. Thereafter, XeF ₂ gas is introduced into the processing chamber from the gas supply device, and an oxide film (for example, a natural oxide film) is formed with an etching gas composed of non-excited XeF ₂ gas.
The substrate can be etched without any hindrance.

According to a second micromachine manufacturing apparatus of the present invention, a processing chamber in which a substrate is etched, an electrode to which high-frequency power is applied, an electrode provided in the processing chamber, and a supply of XeF ₂ gas to the processing chamber And a gas supply device.

In the second micromachine manufacturing apparatus,
Since the high-frequency power is applied and the electrode provided in the processing chamber is provided, the etching gas introduced into the processing chamber can be excited by plasma. Therefore, the oxide film formed on the substrate surface can be removed by the plasma-excited etching gas. Thereafter, XeF ₂ gas is introduced into the processing chamber from the gas supply device, and the substrate is etched with an etching gas composed of non-excited XeF ₂ gas without being hindered by an oxide film (for example, a natural oxide film). Will be possible.

As described above, in the first and second micromachine manufacturing apparatuses according to the present invention, the natural oxide film formed on the substrate surface can be removed in advance, so that the natural oxide film formed on the substrate surface can be removed. When etching with XeF ₂ gas molecules not excited by RF or microwave without being affected, uniform etching characteristics can be obtained without generating a delay time in the etching.

In the method of manufacturing a micromachine according to the present invention, a step of etching a layer to be etched made of a silicon-based material formed on a substrate and separating a structure forming layer formed on the layer to be etched from the substrate is performed. A method of manufacturing a micromachine comprising: a step of removing an oxide film formed on a surface of the layer to be etched before etching the layer to be etched; and etching the layer to be etched using XeF ₂ gas. Do. The removal of the oxide film is performed by using an etching gas excited by microwaves or plasma, or by etching with hydrofluoric acid.

The method for manufacturing a micromachine includes a step of removing an oxide film formed on the surface of the layer to be etched before etching the layer to be etched. The natural oxide film can be removed. After that, since the layer to be etched is etched using XeF ₂ gas,
Uniform etching characteristics without any delay time when etching with XeF ₂ gas molecules not excited by RF or microwaves, without being affected by the natural oxide film formed on the surface of the layer to be etched Is obtained.

According to the method of manufacturing a diffraction grating light valve of the present invention, after etching an etching target layer made of a silicon-based material formed on a substrate, after removing an oxide film formed on the surface of the etching target layer, And etching the layer to be etched using a XeF ₂ gas to separate a structure forming layer formed on the layer to be etched from the substrate.

The method for manufacturing a diffraction grating light valve includes a step of removing an oxide film formed on the surface of the layer to be etched before etching the layer to be etched. The natural oxide film formed on the substrate can be removed. Then, Xe
Since the layer to be etched is etched using F ₂ gas, X not excited by RF or microwave is not affected by the natural oxide film formed on the surface of the layer to be etched.
When etching with eF ₂ gas molecules, uniform etching characteristics can be obtained without generating a delay time in the etching. Therefore, the layer to be etched can be etched with high precision.

In the display device of the present invention, the XeF ₂ gas is removed after removing the oxide film formed on the surface of the etching target layer before etching the etching target layer made of the silicon-based material formed on the substrate. A diffraction grating light valve manufactured by a method of manufacturing a diffraction grating light valve including a step of separating a structure forming layer formed on the etching target layer from the substrate by performing etching of the etching target layer using the etching method. Is used.

In the above display device, since the diffraction grating light valve manufactured by the method for manufacturing a diffraction grating light valve is used, a diffraction grating light valve manufactured with high precision can be used. Therefore, the operation accuracy of the diffraction grating light valve can be improved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a first micromachine manufacturing apparatus according to the present invention will be described with reference to the schematic configuration diagram of FIG.

As shown in FIG. 1, the first micromachine manufacturing apparatus 1 includes a processing chamber 11 in which a substrate 91 is etched. A stage 12 on which the base 91 is placed is provided in the processing chamber 11. This processing chamber 11
Is provided with an exhaust pipe 13 to which an exhaust system (not shown) is connected.

The processing chamber 11 is connected to a microwave generator 21 for supplying an etching gas excited by microwaves into the processing chamber 11. The microwave generator 21 includes a microwave generator 23 connected to the processing chamber 11 by a transport pipe 22, a mass flow controller 24 connected in the middle of the transport pipe 22, and a microwave generator 22 connected to the microwave generator 22. For example, 2.45 MHz
And a high-frequency power supply 25 for generating the high-frequency power. Further, a gas supply system (not shown) is connected to the microwave generator 23 so as to supply an etching gas.

A gas supply device 31 for supplying xenon difluoride (XeF ₂ ) gas into the processing chamber 11 is provided.
Is connected. The gas supply apparatus 31 includes a gas generator 32 for sublimating the XeF ₂ accommodating solid generate XeF ₂ gas was generated in the gas generator 32 XeF
₍₂₎ A gas storage unit 33 that stores gas at a predetermined pressure, that is, a stable pressure, and Xe supplied from the gas storage unit 33.
A pressure controller 34 for controlling the pressure of the F ₂ gas is connected to the gas generator 32, the gas storage unit 33, and the pressure controller 34 in this order by a pipe 35, and the outlet side of the pressure controller 34 is processed by a pipe 35 (35 a). It is connected to the chamber 11.

In the first micromachine manufacturing apparatus 1,
Transmits the etching gas excited by the microwave to the processing chamber 1.
1 is provided with a microwave generator 21
And processing the etching gas excited by microwave
The acid introduced into the chamber 11 and formed on the surface of the substrate 99
It is possible to remove the oxide film, and then supply the gas
XeF from device 31_TwoGas is introduced into the processing chamber 11,
Unexcited XeF _TwoEtching gas consisting of gas
Without being hindered by an oxide film (eg, natural oxide film)
The body 91 can be etched. like this
In the first micromachine manufacturing apparatus 1,
Not XeF_TwoEtching with etching gas consisting of gas
Can be performed.
It is effective. In addition, the first microma
The thin manufacturing apparatus 1 includes a microwave generator 21.
Only the device structure is simplified.

Next, an example of an embodiment according to the second micromachine manufacturing apparatus of the present invention will be described with reference to the schematic configuration diagram of FIG.

As shown in FIG. 2, the second micromachine manufacturing apparatus 2 includes a processing chamber 11 in which a substrate 91 is etched. An upper electrode 41 is provided in the processing chamber 11, and a base 9 is provided at a position facing the upper electrode 41.
1 is placed on which a lower electrode 42 is placed. The upper electrode 41 is connected to a high frequency electrode 43 for generating a high frequency of 13.56 MHz, for example. On the other hand, the lower electrode 42
Is connected to a DC power supply 44. Further, the processing chamber 11 is provided with an etching gas introduction part 45 for introducing an etching gas excited by plasma. Further, an exhaust pipe 13 to which an exhaust system (not shown) is connected is provided in the processing chamber 11.
Is provided.

A gas supply device 31 for supplying xenon difluoride (XeF ₂ ) gas into the processing chamber 11 is provided.
Is connected. The gas supply apparatus 31 includes a gas generator 32 for sublimating the XeF ₂ accommodating solid generate XeF ₂ gas was generated in the gas generator 32 XeF
₍₂₎ A gas storage unit 33 that stores gas at a predetermined pressure, that is, a stable pressure, and Xe supplied from the gas storage unit 33.
A pressure controller 34 for controlling the pressure of the F ₂ gas is connected to the gas generator 32, the gas storage unit 33, and the pressure controller 34 in this order by a pipe 35, and the outlet side of the pressure controller 34 is processed by a pipe 35 (35 a). It is connected to the chamber 11.

In the second micromachine manufacturing apparatus 2, the upper electrode 4 to which high-frequency power is applied
1, the etching gas (for example, nitrogen) introduced into the processing chamber 11 from the etching gas introduction unit 45 supplies high frequency power to the upper electrode 41 and direct current power to the lower electrode 43, Upper and lower electrodes 41 and 43
It is excited by the plasma generated between them. The oxide film formed on the surface of the base 91 can be removed by the plasma-excited etching gas.
XeF ₂ gas is introduced into the processing chamber 11 from the gas supply device 31, and the base 91 is etched by an etching gas composed of non-excited XeF ₂ gas without being hindered by an oxide film (for example, a natural oxide film). It becomes possible.
As described above, in the second micromachine manufacturing apparatus 2, it is possible to perform the etching with the etching gas composed of the non-excited XeF ₂ gas, which is effective as a MEMS manufacturing apparatus.

As described above, in the first and second micromachine manufacturing apparatuses 1 and 2 of the present invention, an oxide film (eg, a natural oxide film) formed on the surface of the base 91 can be removed in advance. Xe not excited by RF or microwave without being affected by the oxide film formed on the surface of 91
When etching with gas molecules F _2, uniform etching characteristics without causing a delay time to the etching can be obtained.

Next, an example of the second embodiment of the first and second micromachine manufacturing apparatuses of the present invention will be described with reference to the schematic configuration diagram of FIG. In the second embodiment, a configuration in which an end point detection device for oxide film etching is provided in the first and second micromachine manufacturing apparatuses 1 and 2 described with reference to FIGS. 1 and 2 will be described. In the following description,
A configuration in which an end point detection device for oxide film etching is provided in the first micromachine manufacturing apparatus 1 will be described. In FIG. 3, a part of the microwave generator 21 and the gas generator 31 is not shown.

As shown in FIG. 3, the end point detecting device 51 is provided in an exhaust pipe 13 connecting the above-described processing chamber 11 and an exhaust system (not shown). A gas analyzer 52 for analyzing components is provided.
Further, the gas analyzer 52 determines the etching end point based on the result analyzed by the gas analyzer 52, and when the etching end point is determined, controls the mass flow controller 24 to control the microwave-excited etching gas. After the supply of the XeF ₂ gas is stopped, an end point detection unit 53 that sends a command to start the supply of the XeF ₂ gas by controlling the pressure controller 34 is connected.

By providing the gas analyzer 52, it is possible to analyze the gas in the processing chamber 11.
For example, when an oxide film is etched (radical etching) by a microwave-excited etching gas by performing gas analysis, a change in a radical etching state is detected by detecting an oxygen component of the oxide film, and the detection is performed. An end point is determined by the end point detection unit 53 based on the result.

For example, during the etching of the natural oxide film,
The amount of oxygen gas is detected at an intensity as shown in (1) of FIG. Then, as the etching of the natural oxide film progresses and reaches the etching end point, the detected oxygen gas amount reaches the etching end point level as shown in FIG. 4 (2). That time is determined as the etching end point. Note that each vertical axis shown in FIG. 4 indicates the detection intensity corresponding to the detected gas amount, and each horizontal axis indicates the detected gas component.

When the end point of the etching is determined, the supply of the microwave-excited etching gas is stopped by controlling the mass flow controller 24, and the supply of the XeF ₂ gas is started by controlling the pressure controller 34. As described above, the timing of removing the natural oxide film is determined from the residual gas component, and the radical etching is performed to remove XeF ₂
By switching to etching using gas, it is possible to provide a time-efficient process while maintaining high selectivity.

In the above description, the configuration in which the end point detecting device 51 is provided in the first micromachine manufacturing apparatus 1 has been described.
It is also possible to provide an end point detecting device similar to the above in the second micromachine manufacturing apparatus 2. The end point detection unit in that case determines the etching end point based on the result analyzed by the gas analyzer, and when determining the etching end point, controls the power supply such as a high frequency power supply to stop the generation of plasma. The plasma excitation etching is stopped, the supply of the etching gas supplied from the gas supply unit is stopped, and then a command to control the pressure controller to start the supply of the XeF ₂ gas is sent.

Also in this case, the gas in the processing chamber 11 can be analyzed in the same manner as described above. By performing gas analysis, for example, an oxide film is etched by a plasma-excited etching gas (radical etching)
In this case, a change in the radical etching state is detected by detecting the oxygen component of the oxide film, and the end point detection unit 53 determines the etching end point based on the detection result. When the etching end point is determined, the power supply such as a high frequency power supply is stopped to stop the generation of plasma, and then the supply of the XeF ₂ gas is started by controlling the pressure controller 34. As described above, by switching from radical etching to etching using XeF ₂ gas, it is possible to provide a time-efficient process while maintaining high selectivity.

In any of the above structures, the end point detecting unit 51 is not provided with the end point detecting unit 53, but the etching result is judged by the etching operator based on the analysis result output from the gas analyzing unit 52, and the XeF ₂ gas conversion is performed. Switching can also be performed.

Next, an example of the third embodiment according to the first micromachine manufacturing apparatus of the present invention will be described with reference to the schematic configuration diagram of FIG. In the third embodiment, FIG.
The first micromachine manufacturing apparatus 1 described by
A configuration in which an end point detection device for etching using XeF ₂ gas is provided will be described. In FIG. 5, a part of the microwave generator 21 and the gas generator 31 is partially omitted.

As shown in FIG. 5, in the end point detecting device 61, the transparent glass forming at least a part of the upper wall of the processing chamber 11 facing the stage 12 provided in the processing chamber 11 described above. A plate 62 is provided. In addition, a light source 63 that transmits the glass plate 62 and illuminates the base 91 placed on the stage 12 is installed outside the processing chamber 11. Further, an imaging device 64 for imaging a portion of the base 91 illuminated by the light source 63 is provided, for example, in the processing room 1
1 outside. As the imaging device 64, for example, a CCD camera can be used. in this way,
The end point detection device 61 includes a glass plate 62, a light source 63, and an imaging device 64. Further, the end point detection device 61
At the end, the etching end point is determined based on the image data captured by the imaging device 64, and when the etching end point is determined, the end point for sending a command to control the pressure controller 34 to stop the supply of the XeF ₂ gas is sent. The detection unit 65 is connected.

In the end point detecting device 61, the surface of the base 91 is forcibly irradiated with the light L by the light source 63, and the etching end point is detected by utilizing the interference and the difference in contrast. In the above-described configuration, the etched portion is photographed by the imaging device 64, and the image is processed based on, for example, a difference in contrast to detect an end point. As described above, by performing the end point detection, it is possible to accurately detect the etching end point even in the etching using the XeF ₂ gas in which the emission spectrum method cannot be used.

Next, an example of the first embodiment according to the method for manufacturing a micromachine of the present invention will be described with reference to the schematic configuration diagram of FIG. As an example, a case where the sample described with reference to FIG. 9 is etched will be described.

As shown in FIG. 1, first, the processing chamber 11
The substrate 91 is carried into the inside and is placed on the stage 12. Then, the inside of the processing chamber 11 is brought into an industrial vacuum state by an exhaust system. Next, for example, tetrafluoromethane (CF ₄ ) is used as an etching gas for the oxide film in the microwave generator 23.
And a high frequency power (2.45 GHz) is applied to the microwave generator 23 at 700 W from the high frequency power supply 25 to generate a microwave-excited etching gas. Then, the etching gas excited by the transport pipe 22 is led to the mass flow controller 24, where the flow rate of the etching gas is adjusted so that the pressure in the processing chamber 11 becomes a predetermined pressure (for example, 3 kPa). At that time, the etching gas flow rate was, for example, 150 cm ³ / min. During this time, the inside of the processing chamber 11 is exhausted by the exhaust system.

Then, an excited etching gas is supplied into the processing chamber 11 for, for example, 10 seconds to remove a natural oxide film (not shown) formed on the surface of the polysilicon film 94, which is the film to be etched of the substrate 91. Remove. Immediately after the removal of the native oxide film, the supply of the microwave-excited etching gas is stopped, and
An F ₂ gas is supplied into the processing chamber 11 to form a polysilicon film 9.
4 is isotropically etched. At this time, the gas storage unit 3
456 kPa internal pressure, pressure controller 34
Was set at 111 kPa, and the pressure in the processing chamber 11 was kept at 5 kPa.

The end point of the oxide film etching is detected by the method described with reference to FIG. 3, and the end point of the etching of the polysilicon film 94 using the XeF ₂ gas is detected by the method described with reference to FIG.

The method of manufacturing a micromachine described above includes a step of removing a natural oxide film formed on the surface of the polysilicon film 94 with radicals generated by exciting gas molecules by microwaves. Before the etching of the polysilicon film 94 using the _two gases, the natural oxide film formed on the surface of the polysilicon film 94 can be removed in advance. After that, since the polysilicon film 94 is etched by using the XeF ₂ gas, the polysilicon film 94 is etched without being affected by the natural oxide film formed on the surface of the polysilicon film 94.
When etching with XeF ₂ gas molecules not excited by F or microwaves, uniform etching characteristics can be obtained without generating a delay time in the etching. Further, when a complicated structure such as MEMS is formed by using isotropic etching, a natural oxide film formed in the horizontal direction of the base can be removed unlike the case of etching using ordinary RF. . Further, since the complete dry processing is performed, it is possible to prevent the parts from contacting each other when the MEMS is formed.

As shown in FIG. 6, the XeF_TwoMoth
Etching of the polysilicon film using
Water (H_TwoIf O) is attached, X
eF _TwoXeF by gas and moisture_Two+ H_TwoO → HF +
The reaction of Xe + O proceeds to generate hydrofluoric acid, and
HF + SiO by the generated hydrofluoric acid and oxide film_Two→
H_TwoThe reaction of O + SiF proceeds, and the oxide film is etched.
Some phenomena have been seen.

Next, an example of the second embodiment according to the method for manufacturing a micromachine of the present invention will be described with reference to the schematic configuration diagram of FIG. As an example, a case where the sample described with reference to FIG. 9 is etched will be described.

As shown in FIG. 2, first, the processing chamber 11
The substrate 91 is carried into the inside and is placed on the stage 12. Then, the inside of the processing chamber 11 is brought into an industrial vacuum state by an exhaust system. Next, for example, nitrogen (N ₂ ) as an etching gas for an oxide film is introduced into the processing chamber 11 from the gas supply unit 45 at a flow rate of 100 cm ³ / min.
High frequency power (13.56 MHz) is applied to upper electrode 41 from 3
At 1 kW, for example, and the lower electrode 4
By supplying, for example, 200 W of power to 2, a plasma is generated between the upper power 41 and the lower power 43 to excite nitrogen gas. Then, the pressure of the etching atmosphere by the excited etching gas is adjusted to about 100 Pa by the gas exhaustion by the exhaust system.

Then, an excited etching gas is supplied into the processing chamber 11 for, for example, 10 seconds to remove a natural oxide film (not shown) formed on the surface of the polysilicon film 94 which is the film to be etched of the base 91. Remove. Immediately after the removal of the natural oxide film, the power supply to the upper and lower electrodes 41 and 43 is stopped, and the supply of the etching gas from the gas supply unit is stopped. Thereafter, X is supplied by the gas supply device 31.
An eF ₂ gas is supplied into the processing chamber 11 to etch the polysilicon film 94 isotropically. At this time, the internal pressure of the gas storage unit 33 was 456 kPa, and the pressure controller 3
The pressure in Step 4 was set at 111 kPa, and the pressure in the processing chamber 11 was kept at 5 kPa.

The end point of the oxide film etching is detected by the method described with reference to FIG. 3, and the end point of the etching of the polysilicon film 94 using the XeF ₂ gas is controlled by, for example, the etching time. In the etching of the polysilicon film 94 using the XeF ₂ gas, since the natural oxide film on the surface of the polysilicon film 94 is removed, the end point can be detected by the etching time.

Since the method for manufacturing a micromachine includes a step of removing a natural oxide film formed on the surface of the polysilicon film 94 with radicals generated by exciting gas molecules with plasma, XeF ₂ Before the etching of the polysilicon film 94 using the gas, the natural oxide film formed on the surface of the polysilicon film 94 can be removed in advance. After that, since the polysilicon film 94 is etched by using the XeF ₂ gas, the RF film is not affected by the natural oxide film formed on the surface of the polysilicon film 94.
When etching with XeF ₂ gas molecules not excited by microwaves, uniform etching characteristics can be obtained without generating a delay time in the etching. Further, when a complicated structure such as MEMS is formed by using isotropic etching, a natural oxide film formed in the horizontal direction of the base can be removed unlike the case of etching using ordinary RF. . Further, since the complete dry processing is performed, it is possible to prevent the parts from contacting each other when the MEMS is formed.

Next, as an example of the third embodiment according to the method of manufacturing a micromachine of the present invention, a method of removing a natural oxide film formed on the surface of the polysilicon film by etching with hydrofluoric acid. is there. This method
There is an advantage that the removal process of the natural oxide film can be used by ordinary hydrofluoric acid. As described above, when the polysilicon film is etched by removing the natural oxide film on the surface of the polysilicon film before etching the polysilicon film with gas molecules of XeF ₂ that are not excited by RF or microwaves, In addition, uniform etching characteristics can be obtained without generating a delay time in etching. Further, when forming a complicated structure such as MEMS using isotropic etching,
Unlike the case of etching using ordinary RF, a natural oxide film formed in the horizontal direction of the base can be removed.

Next, an example of an embodiment of a method of manufacturing a diffraction grating light valve according to the present invention will be described with reference to a schematic configuration diagram of FIG. FIG. 7A shows a perspective view,
(2) shows a front view.

As shown in FIG. 6, this diffraction grating light valve 71 is composed of a plurality of bridge-shaped ribbons formed on a common plane in which a silicon oxide film or the like is formed on a silicon substrate. Is made of a laminated film of a silicon nitride film and an aluminum film. The drawing shows a state in which the common plane is grounded, a positive voltage (+ V) is applied to the active ribbon, and the bias ribbon is grounded.

In the method of manufacturing the diffraction grating light valve 71, a polysilicon film is formed in advance in a space which is formed between a plurality of bridge-shaped ribbons and the common plane, and the polysilicon film ( A plurality of ribbons (corresponding to the silicon nitride film 95 described in FIG. 9) are formed on the polysilicon film 94 described in FIG. 9 by, for example, a laminated film of a silicon nitride film and an aluminum film.
Then, after removing the oxide film on the surface of the polysilicon film by the manufacturing method of the micromachine described above, the polysilicon film is removed by etching using XeF ₂ gas,
By forming a plurality of bridge-shaped ribbons on the common plane, the diffraction grating light valve 71 having the above-described configuration is formed.
Is formed.

In the method of manufacturing the diffraction grating light valve 71, the oxide film (natural oxide film) formed on the surface of the polysilicon film is removed before the polysilicon film is removed by etching using XeF ₂ gas. Since the method includes the step, the natural oxide film formed on the surface of the polysilicon film in advance is removed. Thereafter, since the polysilicon film is etched using the XeF ₂ gas, the polysilicon film is etched without being affected by the natural oxide film formed on the surface of the polysilicon film.
Etching proceeds smoothly with gas molecules of XeF ₂ not excited by F or microwaves. Therefore, uniform etching characteristics can be obtained without generating a delay time in the etching, so that the polysilicon film can be etched with high accuracy.

Next, an example of an embodiment of a display device using the diffraction grating light valve will be described with reference to a schematic configuration diagram of FIG. A basic projection system will be described as an example of a display device with reference to FIG.

As shown in FIG. 8, the surface device (projection system) 81 utilizes a simple schlieren optical system, and includes a light source 8 such as a laser light source.
The light L emitted from 2 is reflected by the prism 83 and irradiates the diffraction grating light valve 71. At this time, the primary light L1 is taken out by operating the diffraction grating light valve 71 by static electricity, and the primary light L1 is extracted. The image is formed on the screen 87 through the first lens 84, the slit 85, and the second lens 86.

Since the display device 81 uses the diffraction grating light valve 71 manufactured by the method for manufacturing a diffraction grating light valve, the diffraction grating light valve 71 manufactured with high precision can be used. Therefore, the operation accuracy of the diffraction grating light valve 71 can be improved.

[0063]

As described above, according to the first micromachine manufacturing apparatus of the present invention, since the microwave generator for supplying the etching gas excited by the microwave into the processing chamber is provided, the apparatus is excited. Before etching with a non-existing XeF ₂ gas, an etching gas excited by microwaves can be introduced into the processing chamber to remove an oxide film (eg, a natural oxide film) formed on the substrate surface. . Therefore, etching with the non-excited XeF ₂ gas can be performed without being hindered by the oxide film. Therefore, the problem of causing a delay time in etching is solved, and uniform etching characteristics can be obtained.

According to the second micromachine manufacturing apparatus of the present invention, since the electrode capable of generating plasma is provided in the processing chamber, the substrate surface is etched by the etching gas excited by the plasma generated in the processing chamber. The oxide film (e.g., a natural oxide film) formed on the substrate can be removed. Therefore, unexcited XeF
Etching with _two gases can be performed without being hindered by the oxide film. Therefore, the problem of causing a delay time in etching is solved, and uniform etching characteristics can be obtained.

According to the method of manufacturing a micromachine of the present invention, a step of removing an oxide film (for example, a natural oxide film) on the surface of the layer to be etched before etching the layer to be etched is provided. After the oxide film is removed, the layer to be etched can be etched using a non-excited XeF ₂ gas. Therefore, the problem of causing a delay time in the etching is solved, and the etching process can be performed in a short time, and uniform etching characteristics can be obtained.

According to the method of manufacturing a diffraction grating light valve of the present invention, the step of removing an oxide film (eg, a natural oxide film) on the surface of the layer to be etched before etching the layer to be etched is provided. After the oxide film on the surface of the layer is removed, the layer to be etched can be etched using a non-excited XeF ₂ gas. Therefore,
The problem of causing a delay time in the etching is solved, and the etching process can be performed in a short time.
Uniform etching characteristics can be obtained. for that reason,
Since the layer to be etched can be etched with high precision, the diffraction grating light valve can be manufactured with high precision.

According to the display device of the present invention, since the diffraction grating light valve manufactured by the method of manufacturing the diffraction grating light valve of the present invention is used, it is possible to use a diffraction grating light valve manufactured with high precision. it can. Therefore, the operation accuracy of the diffraction grating light valve can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an embodiment according to a first micromachine manufacturing apparatus of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of an embodiment according to a second micromachine manufacturing apparatus of the present invention.

FIG. 3 is a schematic configuration diagram illustrating an example of a second embodiment of the first and second micromachine manufacturing apparatuses according to the present invention.

FIG. 4 is an explanatory diagram of an end point detection example in the end point detection device by gas analysis.

FIG. 5 is a schematic configuration diagram showing an example of a third embodiment according to the first micromachine manufacturing apparatus of the present invention.

FIG. 6 is a schematic diagram illustrating the effect of moisture on etching using XeF ₂ gas.

FIG. 7 is a schematic configuration diagram showing an example of an embodiment according to a method for manufacturing a diffraction grating light valve of the present invention.

FIG. 8 is a schematic configuration diagram illustrating an example of an embodiment of a display device using a diffraction grating light valve.

FIG. 9 is a schematic configuration perspective view illustrating an etching sample.

FIG. 10 is a diagram showing an observation result of an etching progress state according to an etching time.

FIG. 11 is a cross-sectional view showing an observation result of an etching progress depending on an etching time.

FIG. 12 is a cross-sectional view schematically showing etching using XeF ₂ gas.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st micromachine manufacturing apparatus, 11 ... Processing room, 2
DESCRIPTION OF SYMBOLS 1 ... Microwave generator, 31 ... Gas supply device, 91 ...
Substrate

Claims (12)

[Claims] 1. A processing chamber in which a substrate is etched, a microwave generator for supplying an etching gas excited by a microwave into the processing chamber, and a gas supply apparatus for supplying xenon difluoride gas to the processing chamber. A micromachine manufacturing apparatus comprising: And a gas analyzer connected to the processing chamber for detecting a gas component in the processing chamber, and detecting a change in the gas component obtained by the gas analyzer to determine an end point of the etching. The apparatus according to claim 1, further comprising an end point detection unit. A light source for illuminating the etched portion of the base; an imaging device for imaging the etched portion of the substrate illuminated by the illumination device; and an image obtained by the imaging device being processed to determine an etching end point. 2. The micromachine manufacturing apparatus according to claim 1, further comprising an end point detection unit for determining. 4. A processing chamber in which a substrate is etched, an electrode to which high-frequency power is applied and provided in the processing chamber, and a gas supply device for supplying xenon difluoride gas to the processing chamber. A micromachine manufacturing apparatus. 5. An apparatus for analyzing a gas component in the processing chamber, wherein a gas analyzer connected to the processing chamber and a change in the gas component obtained by the gas analyzer are detected to determine an end point of the etching. The apparatus according to claim 4, further comprising an end point detection unit. 6. A method for manufacturing a micromachine comprising a step of etching a layer to be etched made of a silicon-based material formed on a substrate to separate a structure-forming layer formed on the layer to be etched from the substrate. A step of removing an oxide film formed on the surface of the etching target layer before etching the etching target layer, wherein the etching target layer is etched using xenon difluoride gas. Micromachine manufacturing method. 7. The method according to claim 6, wherein the removal of the oxide film is performed using an etching gas excited by microwaves or plasma. 8. The method according to claim 6, wherein the removal of the oxide film is performed by etching with hydrofluoric acid. 9. The method according to claim 6, wherein the end point of the etching of the oxide film formed on the surface of the layer to be etched is determined by analyzing a residual gas component. 10. The method of manufacturing a micromachine according to claim 6, wherein the end point of the etching of the etching target layer is determined from an image obtained by imaging the etching state of the etching target layer. 11. Before etching a silicon-based material layer formed on a substrate, an oxide film formed on the surface of the layer to be etched is removed. A method of manufacturing a diffraction grating light valve, comprising a step of separating a structure forming layer formed on the etching target layer from the substrate by etching the etching target layer. 12. Before etching a silicon-based material layer formed on a substrate, an oxide film formed on the surface of the layer to be etched is removed. A diffraction grating light valve manufactured by a method for manufacturing a diffraction grating light valve including a step of separating a structure forming layer formed on the etching target layer from the substrate by etching the etching target layer was used. A display device characterized by the above-mentioned.