JP2004106074A - Production method for hollow structure and production method for mems element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize a pattern layout of gas introduction holes in an etching process for a sacrifice layer in the production of a MEMS element. <P>SOLUTION: A production method for hollow structure comprises the steps of forming a drive member on an upper surface of the sacrifice layer formed on a substrate and forming a plurality of the gas introduction holes in the drive member, feeding etching gas through the gas introduction holes 18 and selectively removing the sacrifice layer by etching to form a space between the substrate and the drive member. The plurality of the gas introduction holes 18 are formed over the whole area of the sacrifice layer, and at least mutual distances between the gas introduction holes 18 are equalized. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a hollow structure and a method for manufacturing a MEMS element. More specifically, the present invention relates to a sacrifice layer etching step in manufacturing a hollow structure or a MEMS element, and relates to a layout of gas introduction holes provided for introducing an etching gas such as XeF ₂ gas.
[0002]
[Prior art]
With the development of microtechnology, a so-called micromachine (MEMS: Micro Electro Mechanical System) element and a small device incorporating a MEMS element have been receiving attention.
The MEMS element is formed as a fine structure on a substrate such as a silicon substrate or a glass substrate, and electrically and mechanically controls a driving body that outputs a mechanical driving force and a semiconductor integrated circuit that controls the driving body. This is an element coupled to. The basic feature of the MEMS element is that a driver configured as a mechanical structure is incorporated in a part of the element, and the driver is driven by applying Coulomb attraction between electrodes and the like. It is done electrically. The case where the driving body is driven by another means such as a magnetic force or a piezoelectric effect without depending on the Coulomb attraction between the electrodes is also included in the MEMS element.
[0003]
11A and 11B show a conceptual configuration of a so-called double-supported beam type electrostatic drive type MEMS element. The MEMS element 71 includes a substrate 72, a substrate-side electrode 73 formed on the substrate 72, and a driving body (a so-called beam) 76 having a driving-side electrode 74 disposed in parallel with the substrate-side electrode 73. And a support portion 77 for supporting both ends of the driving body 76. The driver 76 and the substrate-side electrode 73 are electrically insulated by a space 78 therebetween. An insulating film 81 is formed on the entire surface of the substrate 72 including the substrate-side electrode 73, and a driver 76 is arranged to face the insulating film 81. The driving body 76 includes an insulating film 75 such as a silicon nitride film (SiN film) and a driving-side electrode 74 formed on the upper surface thereof and having a thickness of about 100 nm and made of, for example, an Al film.
[0004]
In the MEMS element 71, the driving body 76 is displaced by electrostatic attraction or repulsion between the substrate-side electrode 73 and vibrates, for example, according to the potential applied to the substrate-side electrode 73 and the driving-side electrode 74. The MEMS element 71 detects reflected light in one direction by using the fact that the direction of reflection of the light is different according to the driving position of the beam 6 when the surface is irradiated with light by using the driving side electrode 74 as a light reflecting film. Thus, the present invention can be applied as an optical switch having a switch function. Further, the MEMS element 71 can be applied as a light modulation element that modulates light intensity.
[0005]
[Problems to be solved by the invention]
By the way, a hollow structure used in a MEMS element, that is, a structure in which a space (a so-called hollow portion) between a substrate and a driver is provided, a sacrifice layer is provided between the substrate and the driver in a portion which is subsequently removed to form a space, and After the body is formed, the sacrificial layer can be formed by selectively etching away.
[0006]
In the fabrication process of the MEMS device, sacrificial layer etching related to fabrication of a driving portion is one of important technologies. As the type of the sacrificial layer, an oxide film (SiO ₂ ), silicon (Si), an organic film, or the like is used. As each etching material, a hydrofluoric acid-based solvent, a hydrofluoric acid-based gas, an alkali-based solvent, or the like is used. A gas containing fluorine, an organic solvent, a gas containing oxygen, and the like are used.
[0007]
When silicon is used as the sacrificial layer material, for example, XeF ₂ gas can be used as the etching material. XeF ₂ gas is a sublimable material that is a white solid at room temperature, and has a feature that an etching selectivity between a silicon sacrificial layer and various oxide films, metals, various nitride films, and the like can be obtained as very large as 1000 or more. It is known that Further, its reflection speed is very large even at room temperature, and is generally very short for etching required for a normal MEMS element. In extreme cases, prolonged exposure to gas could even damage the structure, no matter how high the selectivity, due to its high reactivity.
[0008]
Since the etching reaction by the XeF ₂ gas has the above-described characteristics, it is desirable that the etching time of the sacrificial layer to be removed is as equal as possible over the entire device or the entire substrate (wafer) in the manufacturing process of the MEMS device. Generally, a hollow structure is formed by etching. Therefore, since the etching gas is supplied to the etching end face via the gas introduction holes, the number of the gas introduction holes may not be too small, and even if the number of the gas introduction holes is too large, the strength of the structure may be reduced. And it is not preferable because it merely gives a degree of freedom in designing the resonance structure. When uneven etching proceeds in the sacrificial layer region, stress is applied to the structure in the middle of the etching process, and there is a concern that structural destruction may occur during the process.
[0009]
Such a problem can occur not only in the manufacture of the MEMS element but also in the manufacture of the hollow structure.
[0010]
In view of the above, the present invention provides a method for manufacturing a hollow structure and a method for manufacturing a MEMS element, which can reduce the time in the etching step of the sacrificial layer, reduce the consumption of etching gas, and stabilize the hollow structure. To provide.
[0011]
[Means for Solving the Problems]
The method of manufacturing a hollow structure according to the present invention includes the steps of: forming a plurality of gas introduction holes in a covering member formed so as to surround a sacrificial layer on a substrate; supplying an etching gas through the gas introduction holes; Selectively etching away to form a cavity between the substrate and the covering member, forming a plurality of gas introduction holes corresponding to the entire area of the sacrificial layer, at least between the gas introduction holes The gas introduction holes having the same distance are formed so as to be present in the entire region.
[0012]
A method of manufacturing a MEMS device according to the present invention includes a step of forming a driving member on an upper surface of a sacrificial layer formed on a substrate, forming a plurality of gas introduction holes in the driving member, and supplying an etching gas through the gas introduction hole. Forming a space between the substrate and the driving member by selectively etching away only the sacrifice layer, forming a plurality of gas introduction holes corresponding to the entire area of the sacrifice layer, Are formed so that the gas introduction holes having the same distance therebetween exist in the entire region.
[0013]
In the present invention, it is preferable that the shortest distance between the gas introduction holes is larger than twice the distance between the gas introduction hole closest to the outside of the sacrifice layer and the outside of the sacrifice layer.
Further, a silicon material or a silicon material containing a mixture can be used for the sacrificial layer, and XeF ₂ gas can be used for the etching gas.
[0014]
In the method for manufacturing a hollow structure according to the present invention, as a layout of gas introduction holes, the gas introduction holes are formed so as to correspond to the entire area of the sacrificial layer, and at least the distance between the gas introduction holes is equal. Since the holes are formed so as to be present in the whole area (a part of the gas introduction holes may be unequal in distance), the entire area of the sacrificial layer can be removed by etching without uneven etching, and the etching time can be increased. And the amount of etching gas consumed can be reduced.
[0015]
In the manufacturing method of the MEMS element according to the present invention, the gas introduction holes are formed so as to correspond to the entire area of the sacrificial layer, and the gas introduction holes are arranged so that at least the distance between the gas introduction holes is equal. Is formed so as to be present in the entire area (there may be gas introduction holes in which the distance between the parts is not equal), so that the entire area of the sacrificial layer can be removed by etching without unevenness in etching, and the etching time can be reduced. It is possible to achieve shortening, reduction in consumption of etching gas, and the like.
[0016]
By making the shortest distance between the above-mentioned gas introduction holes more than twice the distance between the gas introduction hole closest to the outside of the sacrifice layer and the outside of the sacrifice layer, a new etching gas from the gas introduction hole and the etching occur. The situation where the exchange rate of the reaction product is lowered and etching cannot be performed (so-called deactivation of etching) does not occur, and the entire sacrificial layer can be removed by etching.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
The present invention has been devised based on a detailed study on the layout of gas introduction holes when etching a sacrificial layer selectively using an etching gas and the progress of etching, and an etching gas used for a sacrificial layer removing process. For example, an optimal design guide is provided for a layout of gas introduction holes that contribute to the XeF ₂ gas.
[0019]
FIG. 1 shows an etching apparatus 1 used in an experiment for deriving the present invention. The etching apparatus 1 supplies a reaction chamber 3 in which a sample (wafer) 2 to be etched is arranged and an etching gas, in this example, an XeF ₂ gas 4 obtained by sublimating a XeF ₂ crystal 5 to the reaction chamber 3. And a mass flow controller 7. Reference numeral 8 denotes an exhaust unit provided in the reaction chamber 3, reference numeral 9 denotes a vacuum gauge, and reference numeral 10 denotes a shower head.
[0020]
FIG. 2A shows a main part of Sample 2. In this example, a silicon oxide (SiO ₂ ) film 12, a side wall 13 of a silicon oxide (SiO ₂ ) film, a sacrificial layer flush with the side wall 13, in this example, A polycrystalline silicon film 14 is formed, and a laminated film 17 of, for example, a silicon oxide (SiO ₂ ) film 15 and a silicon nitride (SiN) film 16 serving as a driving unit is formed on the entire surface including the sacrificial layer 14 and the side wall 13. . A gas introduction hole 18 for introducing the XeF ₂ gas 4 as an etching gas is formed in the laminated film 17.
The sample 2 is placed in the reaction chamber 3 and XeF ₂ gas 4 is supplied. The XeF ₂ gas 4 is supplied to the lower layer from the gas introduction hole 18, diffuses and penetrates into the polycrystalline silicon film 14 of the sacrificial layer, reacts with the polycrystalline silicon film 14 and etches the polycrystalline silicon film 14, and A space (also called a cavity) 19 is formed. A reaction product (a so-called reaction product gas) generated by the reaction between the XeF ₂ gas 4 and the polycrystalline silicon film 14 is discharged to the outside through the gas inlet 18.
[0021]
FIG. 3 and FIG. 4 are diagrams showing experimental results for deriving the present invention. FIG. 3 shows a layout of gas introduction holes 18 when the sample is viewed from above. Each Figure A, B, C, Sample ₂ 1 shown in _D, 2 _2, 2 3, _{2 4,} the one the number of each gas inlet holes 18 (lone hole), 2, 4, consists of eight Is done. Then, 3 and 4, the four samples _{2 1,} 2 _2, 2 3, _{2 4,} that is, the pattern of gas inlet holes 18, etched tip of the etching, the movement of the so-called etch front 20 Observed. Reference numeral 22 denotes a scale. FIG. 3 shows the result after etching for 3 minutes, and FIG. 4 shows the result after etching for 12 minutes. The distance between the side walls 13 in the region where the sacrificial layer 14 is formed is 100 μm, and the distance between the gas introduction holes when four gas introduction holes 18 shown in FIGS. 3C and 4C are provided is 24 μm, and FIG. In the case where eight gas introduction holes 18 shown in FIG. 4D were provided, the distance between the gas introduction holes was 10 μm. The larger the number of gas introduction holes 18 in the test pattern, the larger the amount of movement of the etch front 20 is observed, giving a feeling as if the etching rate is high. That is, the etch front length _{L 1} in the gas introduction hole is one sample _{2 1,} gas introduction holes are two sample _{2 2,} etch front length _L 2 _{(= L} 1), etch the gas introducing hole 4 samples _{2 3} front length _{L 3,} the gas introduction hole is eight samples _{2 4} in etch front length _{L 4 (L 1 = L 2} <L 3 <L 4).
[0022]
Thickness _{t 1} of the verification is a sacrificial layer shown in polycrystalline silicon film 14 is 100 nm. The etching rate of the polycrystalline silicon film 14 by the XeF ₂ gas 4 can be isotropically at 1 to 2 μm / min. That is, in this sample 2 [2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ ], the thickness t ₁ (see FIG. 2A) of the polycrystalline silicon film 14 as the sacrificial layer is compared with the reaction rate (ie, the etching rate). small enough to, need be considered only etch front length L ₀ shown in FIG. 2B. In such a reaction system it can be easily understood by putting this phenomenon into account only the etch front length L _0.
[0023]
That is,
2XeF ₂ + si → SiF ₄ ↑ + 2Xe
As shown in FIG. 2, the reaction proceeds between the XeF ₂ gas 4 diffused in the cavity 19 and the Si at the cavity end (corresponding to the etch front) 19a. Since the upper and lower surfaces of the cavity 19 are silicon oxide (SiO ₂ ) films, the etching rates on the upper and lower surfaces are almost negligible. Therefore, the progress of the etch front 20 at this time is a reaction-controlled reaction system for the diffusion of the XeF ₂ gas 4 into the cavity 19.
[0024]
FIG. 5 shows such a situation by actually measuring the layout of four types of gas introduction holes, that is, four types of samples 2 [2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ ], and simulating the behavior of the etch front 20. It is a graph fitted with. Curve a sample _{2 1,} curve b Sample _{2 2,} curve c Sample _{2 3,} curve d represents a sample _{2 4} respectively. The etching start time of the sacrificial layer is substantially after the natural oxide film is removed. The behavior of the etch front depending on the above four layouts matches the calculation result.
[0025]
In the sacrificial layer region, the side wall 13 is covered with the silicon oxide film 13 as shown in FIG. In such a situation, the XeF ₂ gas 4 contributes to the etching in the direction opposite to the side wall 13 via the gas introduction hole 18 without losing the etching reaction on the side wall 13 (so-called deactivation). That is, the results of this experiment suggest that in such a pattern group of the gas introduction holes 18, the area of the sacrificial layer removal region (cavity) 19 viewed from the upper surface is equal in all layouts. I have. It was confirmed that such a situation was reproduced in a pressure range of the XeF ₂ gas 4 in the reaction chamber 3 in a range of 1 Pa to 100 Pa.
[0026]
Based on the experimental results, in the present embodiment, design guidelines as shown in FIGS. 7A, 7B, and 7C, that is, a pattern layout of gas introduction holes were obtained.
{Circle around (1)} The gas introduction holes 18 are arranged at equal distances as much as possible. That is, a plurality of gas introduction holes are formed corresponding to the entire region of the sacrificial layer, and the gas introduction holes are formed so that at least the distance between the gas introduction holes is equal in the entire region. There may be some gas introduction holes in which the distance between the gas introduction holes is not equal, but preferably all the distances between them are equal. This eliminates uneven etching in the sacrificial layer region.
{Circle around (2)} In this case, the interval X between the adjacent gas introduction holes 18 may be long as long as the deactivation of the XeF ₂ gas 4 in the cavity 19 does not occur. It is necessary to pay attention to whether the structure is long and whether the hollow structure has a strength for supporting the cavity 19.
{Circle around (3)} When the interval X is too long, the process time becomes long, and the processing time may not be acceptable as a production technology.
[0027]
FIG. 6 is an experimental example comparing the progress of etching of the sacrificial layer 14. FIG. 6A is a sample having side walls 13 on the lower side and both sides of the sacrifice layer 14 and the etching of the sacrifice layer proceeds only upward. FIG. 6B is a sample in which the side walls 13 are formed on both sides of the paper surface of the sacrifice layer 14, and the etching of the sacrifice layer proceeds upward and downward. The layout was such that eight gas introduction holes 18 were provided for each sample, and all were etched for 15 minutes. The length of the etch front that progresses on the upper side of the paper surface L ₄ are, it was confirmed both the same.
[0028]
The test pattern shown in FIG. 6 confirms that when the distance X between adjacent gas introduction holes exceeds 10 μm, deactivation in the cavity 19 becomes apparent.
6A and 6B, the etch front 20 of FIG. 6A should advance before the etch front 20 of FIG. 6B if both are not deactivated. However, in practice, they are traveling the same distance as shown. The reason is considered as follows. In the sample of FIG. 6A, if the XeF ₂ molecules introduced from the gas introduction hole 18 and proceeding downward in the figure do not deactivate, they turn upward and proceed to participate in the etching of the etch front 20 in FIG. It should be etched more than the upper etch front 20 of the sample. However, since both etching front lengths are the same, in FIG. 6A, it is considered that molecules taking the route of XeF ₂ {2} did not participate in the etching of the etch front 20 and were inactivated. . In the sample of FIG. 6B, the molecules of the route of XeF ₂ {1} are consumed by the etching in the upper part of the figure, and the molecules of the route of XeF ₂ {2} are consumed in the etching of the lower part of the figure.
[0029]
From this result, in the present embodiment, the following design guideline, that is, the pattern layout of the gas introduction holes is expressed. As shown in FIG. 7, the gas introduction holes 18 need to be present at a distance Y (X> 2Y) shorter than half the distance X between the gas introduction holes 18 from the outside of the sacrificial layer, that is, the so-called side wall 13. In other words, the shortest distance X between the gas introduction holes is set to be larger than twice the distance Y between the gas introduction hole closest to the side wall 13 and the outside of the sacrificial layer. This distance Y does not need to be equal to 距離 of the distance X between the gas introduction holes 18, but may be shorter. The reason is that if the side wall 13 of the cavity 19 obtained by etching the sacrificial layer 14 is the silicon oxide film 13 as described above, the XeF ₂ gas is used without deactivation. That is, a reaction product is generated in the vicinity of the side wall 13 of the cavity 19, and when the distance Y increases, the exchange rate between the reaction product and the new XeF ₂ gas decreases, and deactivation of the XeF ₂ gas occurs. The same applies to the distance X.
[0030]
In the present embodiment, in manufacturing the MEMS element, an etching gas is introduced through a gas introduction hole opened in a driving member, which is an etching-resistant member formed by being stacked on the upper surface of the sacrificial layer, and the sacrificial layer is formed. In the step of removing the layer by etching, the layout of the gas introduction holes was arranged such that the intervals between the gas introduction holes were as equal as possible, and the distance from the outside of the sacrificial layer region to the gas introduction holes was also described above. Optimize with constraints. The shortest distance between the gas introduction holes in the optimal arrangement of the gas introduction holes is set to be larger than twice the distance between the gas introduction hole and the side wall closest to the outside (side wall) of the sacrificial layer.
[0031]
In the above-described embodiment, the layout of the gas introduction holes 18 has been described only in two dimensions. This is used in so-called surface MEMS devices. The layout method of the gas introduction holes described in the present invention can be similarly applied to a so-called bulk MEMS element.
For example, with regard to the three-dimensional structure 31 as shown in FIG. 8, when the beam portion 32 supporting the structure is a silicon oxide (SiO ₂ ) film, this portion 32 is connected to the side wall 13 in FIGS. By treating in the same manner, an optimal layout of the gas introduction holes 34 can be obtained. In this case, the isotropic etching shape is not a circle but a sphere, so that the same optimal arrangement can be obtained although the calculation amount increases.
[0032]
In the above example, the present invention is applied to the manufacture of the MEMS element, but the present invention can be applied to a method of manufacturing a so-called hollow structure.
[0033]
FIG. 9 shows an embodiment of the method for manufacturing a hollow structure according to the present invention.
First, as shown in FIG. 9A, a sacrificial layer 42 is deposited on a required substrate 41, and an upper thin film layer 43 is deposited so as to surround the sacrificial layer 42. The sacrificial layer 42 is formed of a material that can be removed with a required etching gas. In this example, the sacrificial layer 42 is formed of polycrystalline silicon. The supporting portion 43a of the upper thin film layer 43 located on the outer periphery of the sacrifice layer 42 corresponds to the above-described side wall.
Next, as shown in FIG. 9B, a plurality of gas introduction holes 44 are formed in the upper thin film layer 43 under the above-described layout conditions. A required etching gas 45 is supplied through the gas introduction holes 44 to etch the sacrificial layer 42. In this example, XeF ₂ gas is used for etching.
In this etching, the etching time is the same in the entire area of the sacrifice layer 42. As shown in FIG. 9C, the sacrifice layer 42 is removed, and the minute hollow having a minute space 46 between the substrate 41 and the upper thin film layer 43 is formed. The structure 47 is obtained.
[0034]
According to the method of manufacturing the hollow microstructure 47 according to the present embodiment, the etching rate is the same over the entire area of the sacrifice layer 42, and the sacrifice layer 42 can be uniformly removed. Since the number of the gas introduction holes 44 is optimized, the strength of the upper thin film layer 43 can be maintained. Therefore, this kind of highly reliable hollow microstructure can be manufactured.
[0035]
FIG. 10 shows an embodiment in which the method of manufacturing a MEMS device of the present invention is applied to the manufacture of an electrostatic drive type MEMS device.
First, as shown in FIG. 10A, a substrate-side electrode 52 is formed on a substrate 51, and an insulating film, for example, a silicon nitride film (SiN film) 53 is deposited on the substrate-side electrode 52. An insulating film may not be formed on the substrate-side electrode 52 in some cases. As the substrate 51, a required substrate such as a substrate obtained by forming an insulating film on a semiconductor substrate such as silicon (Si) or gallium arsenide (GaAs) or an insulating substrate such as a glass substrate can be used. In this example, the substrate 51 is formed by forming an insulating film 55 such as a silicon oxide film on a silicon substrate 54. The substrate-side electrode 52 is formed of an impurity-doped polycrystalline silicon film, a metal film, or the like. In this example, the substrate-side electrode 52 is formed of an impurity-doped polycrystalline silicon film. Next, a sacrifice layer 56 made of, for example, a polycrystalline silicon film is selectively formed on the insulating film 53, and an insulating film 57 made of, for example, a silicon oxide film serving as a support portion is formed on both sides of the sacrifice layer 56. An insulating film, for example, a silicon nitride film (SiN film) 58 is formed on the entire surface of the sacrificial layer 56 and the insulating film 57, and a drive-side electrode 59 made of a metal such as aluminum is formed on the silicon nitride film 58. A driving member (so-called beam) 60 is formed by the silicon nitride film 58 and the driving-side electrode 59.
[0036]
Next, as shown in FIG. 10B, a plurality of gas introduction holes 61 are formed in the driving member 60 under the same layout conditions as described above. A gas capable of etching the sacrifice layer 56, in this example, a XeF ₂ gas 62, is supplied through the gas introduction holes 61 to etch the polycrystalline silicon film 56 as the sacrifice layer.
By this etching, as shown in FIG. 10C, the sacrificial layer 56 is selectively removed to obtain the electrostatic drive type MEMS element 63 in which the minute space 62 is formed between the substrate 51 and the drive member 60.
[0037]
According to the method of manufacturing the MEMS device according to the present embodiment, the etching rate is the same over the entire area of the sacrifice layer 56, and the sacrifice layer 60 can be uniformly removed. Since the number of the gas introduction holes 61 is optimized, the strength of the driving member 60 can be maintained. Therefore, this type of MEMS element with high reliability can be manufactured.
[0038]
In the above example, polycrystalline silicon was used as the sacrifice layer. Alternatively, for example, a mixture, that is, polycrystalline silicon containing the required conductivity-type impurity is deposited by the used CVD apparatus, and this is used as the sacrifice layer. You can also.
[0039]
In the above example, the present invention is applied to the manufacture of an electrostatic drive type MEMS element. However, the present invention is also applicable to the manufacture of a MEMS element in which a drive member can be driven by required means without providing a substrate side electrode and a drive side electrode. The method of the present invention is applicable.
[0040]
【The invention's effect】
According to the present invention, with respect to the etching of the sacrificial layer in which the isotropic etching proceeds, the process time (etching time) can be reduced and the gas introduction hole can be shortened by setting the optimum layout of the gas introduction holes under the above-described conditions. Low consumption and stabilization of the MEMS structure or hollow structure can be achieved. Therefore, a highly reliable MEMS element and hollow structure can be manufactured.
[Brief description of the drawings]
FIG. 1 is a schematic view of an etching apparatus used to obtain a sample according to the present invention.
FIG. 2A is a sectional view of a main part of a sample according to the present invention.
B is a plan view of a main part of the sample according to the present invention.
FIGS. 3A to 3D are comparative diagrams each showing the etching state of the sacrificial layer of the sample according to the present invention.
FIGS. 4A to 4D are comparative diagrams each showing the state of etching of a sacrifice layer of a sample according to the present invention.
FIG. 5 is a graph showing a relationship between an etching time of a sacrificial layer and an etch front length in four types of samples according to the present invention.
FIGS. 6A and 6B are comparison diagrams for observing an etching state of a sacrifice layer for explaining the present invention.
7A to 7C are plan views illustrating examples of a pattern layout of gas introduction holes according to the present invention.
FIG. 8 is a perspective view showing a pattern layout of gas introduction holes in the three-dimensional structure according to the present invention.
9A to 9C are process diagrams showing one embodiment of the method for producing a hollow structure of the present invention.
10A to 10C are process diagrams showing one embodiment of a method for manufacturing a MEMS device of the present invention.
FIG. 11 is a cross-sectional view showing an example of an A electrostatic drive type MEMS element.
B is a plan view thereof.
[Explanation of symbols]
1 ... etching apparatus, 2 _{[2 1,} 2 _2, 2 3, _{2 4]} .. sample, 4 ... XeF ₂ gas, 11 ... substrate, 12, 15 ... silicon oxide film, 13 ... side wall, 14 ... sacrifice layer, 16 ... silicon nitride film, 17 ... laminated film, 18 ... gas introduction hole, 19 ... space (cavity), 20 ... etch Front, 31: three-dimensional structure, 32: beam part, 34: gas introduction hole, 41: substrate, 42: sacrificial layer, 43: upper thin film layer, 44 ... Gas introduction hole, 45 etching gas, 46 hollow part, 47 fine hollow structure, 51 substrate, 52 substrate electrode, 53 insulating film, 56 ..Sacrifice layer, 57 ... Support, 58 ... Insulating film, 59 ... Drive electrode, 60 ... Drive member, 61 ... Gas Entry apertures, 62 ... an etching gas, 62 ... minute space, 63 ... electrostatic drive type MEMS device

Claims (6)

Forming a plurality of gas introduction holes in the covering member formed so as to surround the sacrificial layer on the substrate,
Supplying an etching gas through the gas introduction hole, selectively removing only the sacrificial layer by etching to form a cavity between the substrate and the covering member,
The plurality of gas introduction holes are formed so as to correspond to the entire region of the sacrificial layer, and are formed so that at least the gas introduction holes having the same distance between the gas introduction holes are present in the entire region. Method for producing a hollow structure. 2. The hollow structure according to claim 1, wherein the shortest distance between the gas introduction holes is larger than twice the distance between the gas introduction hole closest to the outside of the sacrifice layer and the outside of the sacrifice layer. Production method. The sacrificial layer using silicon materials including silicon material or mixtures, The process according to claim 1 or 2 hollow structure wherein the use of XeF ₂ gas to the etching gas. Forming a driving member on the upper surface of the sacrificial layer formed on the substrate, and forming a plurality of gas introduction holes in the driving member;
Supplying an etching gas through the gas introduction hole, selectively removing only the sacrificial layer by etching to form a space between the substrate and the driving member,
The plurality of gas introduction holes are formed so as to correspond to the entire region of the sacrificial layer, and are formed so that at least the gas introduction holes having the same distance between the gas introduction holes are present in the entire region. A method of manufacturing a MEMS device. 5. The MEMS device according to claim 4, wherein the shortest distance between the gas introduction holes is larger than twice the distance between the gas introduction hole closest to the outside of the sacrifice layer and the outside of the sacrifice layer. Method. Using silicon materials including silicon material or mixture to the sacrificial layer, the manufacturing method of the MEMS device according to claim 4 or 5, wherein the use of XeF ₂ gas to the etching gas.

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