JP2011096971A - Method and apparatus for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for manufacturing a semiconductor device, capable of increasing the accuracy of etching amount. <P>SOLUTION: A reaction chamber 31 of a manufacturing apparatus 30 is divided into a first reaction chamber 31a and a second reaction chamber 31b by a partition member 50. The reaction chambers are not communicated with each other. An SOI substrate S3 and an SOI substrate S1 are arranged in the first reaction chamber 31a and the second reaction chamber 31b, respectively. Accordingly, there is no risk that an embedded oxide film 43 is excessively etched by allowing H<SB>2</SB>O generated from one SOI substrate by the reaction of hydrofluoric acid and silicon oxide to be adsorbed by the other SOI substrate and allowing adsorbed H<SB>2</SB>O to react with hydrofluoric acid. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a manufacturing method and a manufacturing apparatus for a semiconductor device, and more particularly, when a sacrificial layer reacts with an etching gas when the sacrificial layer is dry-etched with respect to a semiconductor device including a silicon substrate having a sacrificial layer. The present invention relates to a semiconductor device manufacturing method and a manufacturing apparatus in which a reaction product containing H ₂ O is generated.

  Conventionally, as a method of dry etching a sacrificial layer on a silicon substrate having a sacrificial layer, an etching gas formed by mixing methanol vapor with anhydrous hydrofluoric acid gas (hereinafter referred to as hydrofluoric acid gas) is used. A method of dry etching a sacrificial layer is known (Patent Document 1).

Japanese Patent Laying-Open No. 2006-167849 (paragraphs 62 to 64, FIG. 1).

The inventors of this application have considered a method and apparatus for manufacturing a semiconductor device that controls H ₂ O, which is a reaction product. 10A and 10B are explanatory views of the manufacturing apparatus, wherein FIG. 10A is an explanatory view showing the manufacturing apparatus seen from the side, and FIG. 10B is a longitudinal section of an SOI (silicon on insulator) substrate showing the middle of etching. It is explanatory drawing.

The manufacturing apparatus 100 includes a reaction chamber (vacuum chamber) 101. The reaction chamber 101 is configured so that three SOI substrates S1, S2, and S3 can be arranged in the stacking direction. Each SOI substrate is arranged such that the substrate surfaces are opposed to each other with a certain distance between the substrate surfaces. The planar shape of each SOI substrate is a known substantially circular shape.
In addition, the reaction chamber 101 includes an inlet 102 for introducing an etching gas formed by mixing a vapor of methanol (MeOH) or ethanol (C ₂ H ₆ O) into hydrofluoric acid gas (HF), and a reaction during dry etching. And a discharge port 103 for discharging the generated reaction product.

  As shown in FIG. 10B, each SOI substrate has a structure in which a first silicon layer 41 and a second silicon layer 44 as a support substrate are stacked via a buried oxide film 43 as a sacrificial layer. In addition, a silicon oxide film 42 as a sacrificial layer is formed on the back surface of the first silicon layer 41. The silicon oxide films 42 and 43 are formed in the process of oxidizing the silicon layer 44 when the SOI substrate is formed. The silicon oxide film 43 is formed to increase the rigidity of the SOI substrate.

When the etching gas is introduced into the reaction chamber 101 from the introduction port 102, hydrofluoric acid (HF) and the oxide film (SiO ₂ ) contained in the etching gas chemically react, and the buried oxide film 43 and the silicon oxide film 42 are reacted. Is etched. At this time, SiF ₄ (silicon tetrafluoride) and H ₂ O are generated as reaction products.

However, H ₂ O generated in a certain SOI substrate is adsorbed by another SOI substrate by convection of an etching gas. In addition, H ₂ O generated in the SOI substrate disposed above is lowered by gravity and is adsorbed by the SOI substrate disposed below. Then, as shown in the following chemical formulas (1) and (2), H ₂ O adsorbed on the SOI substrate reacts with hydrofluoric acid and excessively etches the buried oxide film 43.

That is, the difference in etching amount increases between a portion where H ₂ O is adsorbed and a portion where H ₂ O is not adsorbed, or between a portion where the amount of H ₂ O adsorbed is large and a portion where it is small. In addition, since the SOI substrate disposed below adsorbs H ₂ O generated from the SOI substrate disposed above the SOI substrate, the SOI substrate disposed below the SOI substrate disposed above the SOI substrate. There is also a problem that the etching amount becomes large.

2HF + H ₂ O → H ₃ O (+) + HF ₂ (−) (1)

SiO ₂ + 2H ₃ O (+) + 2HF ₂ (−) → SiF ₄ + 4H ₂ O (2)

In particular, as shown in FIG. 10B, since the silicon oxide film 42 is formed on the entire back surface of the SOI substrate, a large amount of H ₂ O is generated from the silicon oxide film 42. For this reason, the SOI substrate disposed below increases the amount of adsorption of H ₂ O generated from the back surface of the SOI substrate disposed above, and the buried oxide film 43 is easily etched excessively.

  Accordingly, the present invention has been made to solve the above-described problem, and an object of the present invention is to realize a semiconductor device manufacturing method and manufacturing apparatus capable of increasing the etching amount accuracy.

In order to achieve the above object, a first feature of the present invention is that a plurality of silicon substrates (S1, S3) having sacrificial layers (42, 43) are placed in a reaction chamber (31) so that the substrate surfaces face each other. And a step of dry etching the sacrificial layer by reacting the etching gas introduced into the reaction chamber with the sacrificial layer, and a reaction product containing H ₂ O is generated by the reaction. In the method of manufacturing a semiconductor device, a member (50, 60, 80) having the property that at least H ₂ O of the reaction product is difficult to permeate is formed between the silicon substrates of the plurality of silicon substrates disposed in the reaction chamber. It is that it arrange | positions so that the predetermined range may be divided.

A second feature of the present invention is that a plurality of silicon substrates (S1, S3) having a sacrificial layer (42) on at least one substrate surface are arranged in a reaction chamber so that the substrate surfaces face each other, In a method of manufacturing a semiconductor device, the method includes a step of dry-etching the sacrificial layer by reacting an etching gas introduced therein and the sacrificial layer, and a reaction product containing H ₂ O is generated by the reaction. In order to cover a predetermined range of each sacrificial layer of the silicon substrate (S3) disposed at least above the silicon substrate (S1) disposed at the bottom of the plurality of silicon substrates disposed in the reaction chamber. A member (70) having the property that at least H ₂ O of the reaction product is difficult to permeate.

  A third feature of the present invention is that, in the first feature described above, each of the silicon substrates (S1, S3) has the sacrificial layer (42) formed on at least one substrate surface.

  According to a fourth feature of the present invention, in any one of the first to third features described above, an area of the member facing the silicon substrate is larger than a substrate area of the silicon substrate.

  According to a fifth feature of the present invention, in the fourth feature described above, each of the silicon substrates (S1, S3) is partitioned by the member (50), and each space (31a) formed by the partition is defined. , 31b) are not in communication with each other.

A sixth feature of the present invention is that, in any one of the first to fifth features described above, the member is a silicon substrate (60) that does not generate H ₂ O by the reaction.

A seventh feature of the present invention is that, in any one of the first to fifth features described above, the member has a property of adsorbing the H ₂ O.

  According to an eighth feature of the present invention, in any one of the first to seventh features described above, the reaction chamber (31) has an introduction port (32) for introducing the etching gas into the reaction chamber. And a discharge port (33) for discharging the reaction product from the reaction chamber is disposed below, and the silicon substrates are disposed laterally with the substrate surfaces facing each other. It is to be configured to be.

  A ninth feature of the present invention is that, in any one of the first to eighth features described above, a heater (90) is built in the member (80).

  According to a tenth feature of the present invention, in any one of the first to ninth features described above, the sacrificial layer (42, 43) is a silicon oxide layer, and the etching gas is anhydrous hydrogen fluoride. It contains an acid gas.

  In addition, the code | symbol in each said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

According to the first feature described above, the member having the property that at least H ₂ O of the reaction product does not easily permeate defines a predetermined range between the silicon substrates of the plurality of silicon substrates arranged in the reaction chamber. Therefore, it is possible to make it difficult for H ₂ O generated as a reaction product to move between silicon substrates.
Therefore, the sacrificial layer is not excessively etched by H ₂ O adsorbed on the silicon substrate, so that the accuracy of the etching amount can be increased.

In particular, when the sacrificial layer is formed on at least one substrate surface of each silicon substrate as in the third feature described above, the H generated on one substrate surface of the silicon substrate disposed above is formed. ₂ O tends to be adsorbed on the surface of the silicon substrate disposed below.
However, according to the first feature described above, since H ₂ O generated on one substrate surface of the silicon substrate disposed above is blocked by the above member, the H ₂ O is disposed below. It is difficult to adsorb on the substrate surface of the silicon substrate.
Therefore, the sacrificial layer is not excessively etched by H ₂ O adsorbed on the silicon substrate, so that the accuracy of the etching amount can be increased.

According to the second feature described above, the predetermined ranges of the respective sacrificial layers of the silicon substrate disposed at least above the silicon substrate disposed at the bottom of the plurality of silicon substrates disposed in the reaction chamber are respectively set. a member for covering, at least H _{2 O} is for comprising a member having a hard property transmitted, H ₂ O from the sacrificial layer formed on one substrate face of the silicon substrate disposed above the reaction product Can be prevented from being generated.
Therefore, H ₂ O generated from the sacrificial layer formed on one substrate surface of the silicon substrate disposed above is adsorbed by the silicon substrate disposed below, and the sacrificial layer is absorbed by the adsorbed H ₂ O. Since it is difficult to cause a situation in which the etching is excessively etched, the accuracy of the etching amount can be increased.

According to the fourth feature described above, since the area of the member facing the silicon substrate is larger than the substrate area of the silicon substrate, H ₂ O generated as a reaction product further moves between the silicon substrates. Can be difficult.
Therefore, since the situation that the sacrificial layer is excessively etched by H ₂ O adsorbed on the silicon substrate is less likely to occur, the accuracy of the etching amount can be further increased.

According to the fifth feature described above, the silicon substrates are partitioned by the member, and the spaces formed by the partitions are not in communication with each other, and thus H ₂ generated as a reaction product. It is possible to prevent O from moving between the silicon substrates.
Therefore, H ₂ O generated from another silicon substrate is not adsorbed, and thereby the sacrificial layer is not excessively etched, so that the accuracy of the etching amount can be further improved.

According to the sixth feature described above, the member is a silicon substrate that does not generate H ₂ O by the reaction, and a silicon substrate that can be obtained in the process of manufacturing a silicon substrate to be etched is used. Since it is possible, it is not necessary to manufacture a dedicated member.
Therefore, an increase in manufacturing cost of the semiconductor device can be suppressed.

According to a seventh aspect described above, the member, the order and has a property of adsorbing of H _{2 O,} is produced by the reaction of the, it is possible to adsorb of H _{2 O} has reached the member Further, the amount of H ₂ O adsorbed on the silicon substrate can be further reduced.

According to the eighth feature described above, the reaction chamber has an inlet for introducing an etching gas into the reaction chamber disposed above, and a discharge port for discharging the reaction product from the reaction chamber disposed below. and, for each of the silicon substrate is configured to be positioned laterally to each other are opposed to each substrate surface, of H _{2 O} produced by the reaction can be moved in the direction of gravity.
Therefore, the amount of adsorption of H ₂ O generated by the reaction to the silicon substrate can be further reduced.

According to the ninth feature described above, since the heater is built in the member, H ₂ O adsorbed on the silicon substrate can be evaporated by heat generated from the heater. Further, H ₂ O adsorbed on the member can also be evaporated.
Therefore, the amount of adsorption of H ₂ O generated by the reaction to the silicon substrate can be further reduced.

As in the tenth feature described above, when the sacrificial layer is a silicon oxide layer and the etching gas contains anhydrous hydrofluoric acid gas, the anhydrous hydrofluoric acid gas and silicon oxide react to react with H ₂ O. Is easily generated.
However, if any one of the first to ninth features described above is used, the generated H ₂ O is adsorbed to the silicon substrate, and it is difficult for the etching to proceed excessively. Can be increased.

It is explanatory drawing which shows the outline of the manufacturing apparatus which concerns on 1st Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is SOI arrange | positioned at the manufacturing apparatus shown to (a). It is an enlarged view of a board | substrate and a partition member. It is explanatory drawing which saw through the manufacturing apparatus shown to Fig.1 (a) from upper direction. It is explanatory drawing which shows the outline of the manufacturing apparatus which concerns on 2nd Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is SOI arrange | positioned at the manufacturing apparatus shown to (a). It is an enlarged view of a substrate and a dummy silicon substrate. It is explanatory drawing which shows the content of experiment, (a) is a graph which shows an experimental result, (b) is explanatory drawing of a prior art, (c) is explanatory drawing of this invention. It is explanatory drawing of the example of a change of 2nd Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is the SOI substrate and dummy dummy which are arrange | positioned at the manufacturing apparatus shown to (a) It is an enlarged view of a silicon substrate. It is explanatory drawing which shows the outline of the manufacturing apparatus which concerns on 3rd Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is SOI arranged in the manufacturing apparatus shown to (a) It is an enlarged view of a board | substrate and a tray. It is explanatory drawing which shows the outline of the manufacturing apparatus which concerns on 4th Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is the dummy arrange | positioned at the manufacturing apparatus shown to (a). It is a top view of the board | substrate of. It is explanatory drawing of the example of a change of 4th Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is the plane of the dummy board | substrate arrange | positioned at the manufacturing apparatus shown to (a) FIG. It is explanatory drawing which shows the outline of the manufacturing apparatus which concerns on 5th Embodiment, (a) is explanatory drawing which saw through the manufacturing apparatus from the side, (b) is SOI arrange | positioned at the manufacturing apparatus shown to (a). It is an enlarged view of a substrate and a dummy silicon substrate. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the manufacturing apparatus which inventors of this application considered, (a) is explanatory drawing which shows a manufacturing apparatus seeing through from the side, (b) is SOI (silicon on insulator) which shows the middle of etching It is a longitudinal cross-sectional explanatory drawing of a board | substrate. It is explanatory drawing which shows the example of a change of 1st Embodiment. It is explanatory drawing which shows the example of a change of 2nd Embodiment.

<First Embodiment>
A first embodiment according to the present invention will be described with reference to the drawings. 1A and 1B are explanatory views showing an outline of a manufacturing apparatus used in the method for manufacturing a semiconductor device according to the first embodiment. FIG. 1A is an explanatory view of the manufacturing apparatus seen from the side, and FIG. It is an enlarged view of the SOI substrate and partition member which are arrange | positioned at the manufacturing apparatus shown to (a). FIG. 2 is an explanatory view of the manufacturing apparatus shown in FIG. In FIG. 1B, the SOI substrates S1 and S3 are drawn larger than the actual dimensions for easy understanding of the structure. Further, the same components as those shown in FIG. 10 are denoted by the same reference numerals.

The manufacturing apparatus 30 includes a reaction chamber (vacuum chamber) 31 therein. The reaction chamber 31 is divided into a first reaction chamber 31a and a second reaction chamber 31b by a partition member 50. No gap is formed between the partition member 50 and the peripheral wall 31 c of the reaction chamber 31. For this reason, the first reaction chamber 31 a and the second reaction chamber 32 a are maintained in a non-communication state by the partition member 50. The partition member 50 is made of a material such as Hastelloy (registered trademark) that has excellent corrosion resistance and does not transmit or hardly transmit H ₂ O.

  An SOI substrate S3 is disposed in the upper first reaction chamber 31a, and an SOI substrate S1 is disposed in the lower second reaction chamber 31b. The SOI substrate S3 is disposed in a non-contact state with the wall surface of the first reaction chamber 31a and the partition member 50. The SOI substrate S1 is disposed in a non-contact state with the wall surface of the second reaction chamber 31b and the partition member 50.

  The SOI substrates S1 and S3 include a first silicon layer 41 to be a support substrate, a buried oxide film 43 formed on the surface layer, a second silicon layer 44 formed on the surface layer, and a first silicon layer. And a silicon oxide film 42 formed on the back surface. The silicon oxide film 42 and the buried oxide film 43 are sacrificial layers. The silicon oxide film 42 is formed on the entire back surface of the SOI substrate in order to increase the rigidity of the SOI substrate.

First, the SOI substrates S1 and S3 are transferred into the reaction chamber 31 by a transfer device (not shown). Next, an etching gas obtained by mixing a vapor of methanol (MeOH) or ethanol (C ₂ H ₆ O) into hydrofluoric acid gas (HF) is introduced from the inlet 32. Thereby, etching of the silicon oxide film 42 and the buried oxide film 43 starts. This etching proceeds by the reaction between hydrofluoric acid and silicon oxide as shown in the following formula (3).

SiO ₂ + 4HF + 2MeOH → SiF ₄ ↑ + 2H ₂ O ↑ + 2MeOH ↑ (3)

As shown in the above formula (3), H ₂ O is generated by the above reaction. Although H ₂ O generated in the SOI substrate S3 moves downward by gravity, as shown in FIG. 1B, the SOI substrates S1 and S3 are separated from each other by the partition member 50. , H ₂ O generated from one SOI substrate is not adsorbed to the other SOI substrate.

In particular, more H ₂ O than the buried oxide film 43 is generated from the silicon oxide film 42 formed on the entire back surface of the SOI substrate. Further, the SOI substrate 1 is disposed immediately below the SOI substrate S3, and the silicon oxide film 42 of the SOI substrate S3 and the surface of the SOI substrate S1 are disposed to face each other. For this reason, H ₂ O generated from the back surface of the SOI substrate S3 is easily adsorbed to the buried oxide film 43 of the SOI substrate S1, but since the partition member 50 exists, such adsorption can be completely prevented. .

As described above, since H ₂ O generated in the upper SOI substrate S3 is not adsorbed to the lower SOI substrate S1, the etching of the buried oxide film 43 of the SOI substrate S1 does not proceed excessively. Therefore, the accuracy of the etching amount can be increased.
In particular, in the case where the second silicon layer 44 constitutes a microstructure, if the etching of the buried oxide film 43 proceeds excessively, the operation of the second silicon layer 44 may be adversely affected. If the method for manufacturing a semiconductor device according to this embodiment is used, the etching of the buried oxide film 43 is not likely to proceed excessively, so that the operation of the second silicon layer 44 is not adversely affected.

For example, when the SOI substrate is for manufacturing an acceleration sensor, the second silicon layer 44 is a fixed electrode and a movable electrode, and the movable electrode has a cantilever structure, etching of the portion that supports the movable electrode is performed. If it proceeds excessively, the tip of the movable electrode comes into contact with the surface of the first silicon layer 41 due to its own weight, and the detection accuracy of the acceleration sensor may be reduced.
However, if the method for manufacturing a semiconductor device according to the above-described embodiment is used, there is no possibility that the etching of the portion supporting the movable electrode proceeds excessively, so that the tip of the movable electrode contacts the surface of the first silicon layer 41. Therefore, there is no possibility that the detection accuracy of the acceleration sensor is lowered.

(Example of change)
As shown in FIG. 11, the reaction chamber 31 is divided into a first reaction chamber 31a, a second reaction chamber 31b, and a third reaction chamber 31d by two partition members 50, and SOI substrates S3, S1, and S4 are placed in each reaction chamber. It is also possible to etch three SOI substrates at the same time. Further, the number of compartments of the reaction chamber 31 can be increased by the partition member 50, and four or more SOI substrates can be simultaneously etched. That is, the reaction chamber 31 is divided into (n + 1) pieces by using the n partition members 50, and one SOI substrate is arranged in each of the divided reaction chambers, thereby simultaneously (n + 1) pieces of SOI. The substrate can also be etched.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings. 3A and 3B are explanatory views showing an outline of a manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment. FIG. 3A is an explanatory view of the manufacturing apparatus seen from the side, and FIG. 2 is an enlarged view of an SOI substrate and a dummy silicon substrate disposed in the manufacturing apparatus shown in FIG.

  The manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment is characterized in that a dummy silicon substrate is disposed between SOI substrates. As shown in FIG. 3, a dummy silicon substrate 60 is disposed between the SOI substrates S1 and S3. A silicon oxide film is not formed on the front and back surfaces of the dummy silicon substrate 60. The substrate surface of the dummy silicon substrate 60 is the same as the SOI substrates S1 and S3 to be etched.

  The dummy silicon substrate 60 is transferred into the reaction chamber 31 together with the SOI substrates S1 and S3 to be etched by a transfer device (not shown), and the SOI substrates S1 and S3 and the dummy silicon substrate 60 are inside the reaction chamber 31. They are arranged in the vertical direction at a predetermined interval from each other. That is, originally, when three SOI substrates are transferred to the reaction chamber 31, the central SOI substrate is changed to a dummy silicon substrate 60 and transferred.

As described above, by arranging the dummy silicon substrate 60 between the SOI substrates S1 and S3, the dummy silicon substrate 60 prevents the H ₂ O generated from the SOI substrate S3 from being lowered.
Therefore, since the buried oxide film 43 of the SOI substrate S1 disposed below is not excessively etched, the accuracy of the etching amount can be increased.

(Experiment)
The inventors of this application conducted an experiment to know the effect of using the dummy silicon substrate described above. 4A and 4B are explanatory diagrams showing the contents of this experiment, in which FIG. 4A is a graph showing experimental results, FIG. 4B is an explanatory diagram of the prior art, and FIG. 4C is an explanatory diagram of the present invention.

  As shown in FIG. 4B, the prior art has a configuration in which SOI substrates S1, S2, and S3 are arranged in order from the bottom and a dummy silicon substrate 60 is arranged on the top as shown in FIG. In the present invention, a dummy silicon substrate 60 is disposed between the SOI substrates S1 and S3, and a dummy silicon substrate 60 is disposed above the SOI substrate S3. The structures of the SOI substrates S1 to S3 are the same as the structure shown in FIG. 1B, and a manufacturing apparatus that can arrange four SOI substrates is used.

  An etching gas formed by mixing methanol (MeOH) vapor with hydrofluoric acid gas (HF) was introduced from the inlet 32, and the silicon oxide film 42 and the buried oxide film 43 were etched. Then, the etching amount (μm) of the buried oxide film 43 of the SOI substrates S1 to S3 was measured. Moreover, the minimum value and the maximum value of the etching amount in each SOI substrate were measured, and the average value was calculated. For the measurement of the etching amount using the configuration of the present invention, a total of 6 lots were prepared with the SOI substrates S1 and S3 used in one measurement as one lot, and etching was performed in units of one lot.

  As a result, as shown in FIG. 4A, it was found that the variation between SOI substrates (the amount of change in the average value of each SOI substrate) is smaller in the present invention than in the prior art. Specifically, the average value of the variation in the etching amount from the first lot to the sixth lot of the present invention was 6.02 ± 1.01 μm, whereas the conventional technique has 7.08 ± 2.65 μm. In the present invention, the variation in the etching amount can be reduced by 1.64 μm as compared with the prior art.

It was also found that the variation in etching amount (a value obtained by subtracting the minimum value from the maximum value) in the same SOI substrate is smaller in the present invention than in the prior art.
That is, it has been proved that the accuracy of the etching amount can be improved by disposing a dummy silicon substrate between the SOI substrates as in the present invention.

(Example of change)
(1) Further, as shown in FIG. 12, a dummy silicon substrate 60 may be disposed between the three SOI substrates S3, S1, and S4, and the three SOI substrates may be simultaneously etched. Alternatively, dummy silicon substrates 60 may be disposed between four SOI substrates, and four or more SOI substrates may be etched simultaneously. That is, one dummy silicon substrate 60 is arranged between m SOI substrates, and a total of (m−1) dummy silicon substrates 60 are used to simultaneously etch m SOI substrates. You can also

(2) Further, in the case where H ₂ O generated in the upper SOI substrate wraps around the end of the dummy silicon substrate and reaches the lower SOI substrate, as shown in FIG. In addition, the dummy silicon substrate can be formed to have a substrate area larger than that of the SOI substrate, and the wraparound of H ₂ O can be suppressed.

(3) When the region where the etching amount varies is specified, it is not always necessary to form the same shape and size as the SOI substrate, and the above-described dummy silicon substrate or the like is created corresponding to the specified region. You can also.

(4) Instead of a dummy silicon substrate, a member formed in a plate shape by a material other than silicon can be used. However, as the material, a material such as Hastelloy that has excellent corrosion resistance and does not generate a substance such as H ₂ O that adversely affects etching by reaction with an etching gas is selected.

<Third Embodiment>
Next, a third embodiment of the invention will be described with reference to the drawings. 6A and 6B are explanatory views showing an outline of a manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment. FIG. 6A is an explanatory view in which the manufacturing apparatus is seen from the side, and FIG. It is an enlarged view of the SOI substrate and tray arrange | positioned at the manufacturing apparatus shown in FIG.

A manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment includes a tray on which an SOI substrate is placed. As shown in FIG. 6, the SOI substrates S <b> 1 to S <b> 3 are each placed on a tray 70. The tray 70 is formed in a size that allows the SOI substrate to be placed on its surface, and a peripheral wall 71 is continuously formed on the periphery thereof. That is, the SOI substrate placed on the tray 70 is in a state where the back surface thereof is in contact with the surface of the tray 70 and the end surface is surrounded by the peripheral wall 71. The tray 70 is made of a material that has excellent corrosion resistance and does not generate H ₂ O by reaction with an etching gas, such as Hastelloy.

  Each SOI substrate is transferred to the reaction chamber 31 by the transfer device while being placed on the tray 70. Alternatively, the tray 70 may be disposed in the reaction chamber 31 in advance, and the conveyed SOI substrate may be placed on the tray 70. Further, depending on the magnitude of the variation in etching, it is not always necessary to form the peripheral wall 71 of the tray 70, and a plate-like tray can also be used.

In this way, since each of the SOI substrates S1 to S3 is accommodated in the tray 70, H ₂ O generated from the upper SOI substrate due to the reaction with the etching gas can be made difficult to move downward. In particular, since the back surface of the SOI substrate is in contact with the surface of the tray 70, H ₂ O can be prevented from being generated from the silicon oxide film 42 formed on the back surface of the SOI substrate.
Accordingly, the SOI substrate disposed below can be prevented from being excessively etched, and the etching accuracy can be increased.
Note that two or four or more SOI substrates can be etched simultaneously by placing each SOI substrate on the tray 70.

<Fourth embodiment>
Next, a fourth embodiment of the invention will be described with reference to the drawings. 7A and 7B are explanatory views showing an outline of a manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment. FIG. 7A is an explanatory view of the manufacturing apparatus seen from the side, and FIG. It is a top view of the dummy board | substrate arrange | positioned at the manufacturing apparatus shown in FIG.

The manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment is characterized in that a plate-like member provided with a heater is disposed between the SOI substrates. As shown in FIG. 7, a heater 90 is built in a plate-like member 80 formed in an SOI substrate shape. The plate member 80 is made of a material having high heat transfer efficiency such as stainless steel. In this embodiment, the heater 90 is formed in a substantially rectangular planar shape. The heater 90 is controlled by a heater control device (not shown) and heats the plate member 80. The heat generated by this heating is transferred to the SOI substrates S1 and S3, the H ₂ O adsorbed on both SOI substrates is evaporated, and the progress of etching due to the reaction of the adsorbed H ₂ O with hydrofluoric acid is suppressed.

That, _{H 2} O generated from the SOI substrate S3 is but downward movement of the plate member 80 is prevented, for example, even when _{the H 2} O is adsorbed to the SOI substrate S1, the adsorbed _{H 2} O Since it can be evaporated by the heat generated from the plate-like member 80, the accuracy of the etching amount can be further enhanced.

  As the heater 90, a sheathed heater or a cartridge heater can be used. The sheathed heater is a metal pipe with a heating wire coiled, filled with insulating powder in the metal pipe and sealed so that the metal pipe and heating wire do not come into contact with each other. It is a heater having a structure in which heat is applied to generate heat. Also, the cartridge heater is a heating wire wound around a bobbin formed of an inorganic insulator (such as magnesia) in a coil shape, inserted into a metal sheath, and filled with a powdered inorganic insulator in the gap. It is a heater.

(Example of change)
As shown in FIG. 8, a plurality of heaters 90 can be incorporated in the plate member 80. Further, the arrangement of the heater 90 may be changed so as to heat the region where the amount of adsorption of H ₂ O is relatively large. Furthermore, it may be changed the heating temperature of the heater 90 in accordance with the amount of adsorption region H 2 _O is adsorbed. Further, the plate member 80 may be formed by the heater itself.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 9 is an explanatory view showing an outline of a manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment. FIG. 9A is an explanatory view of the manufacturing apparatus seen from the side, and FIG. 2 is an enlarged view of an SOI substrate and a dummy silicon substrate disposed in the manufacturing apparatus shown in FIG.

  The manufacturing apparatus used in the method for manufacturing a semiconductor device according to this embodiment is characterized in that an SOI substrate is placed upright in a reaction chamber. As shown in FIG. 9, the manufacturing apparatus 30 has an introduction port 32 disposed above and a discharge port 33 disposed below. In the reaction chamber 31, SOI substrates S1 and S3 are arranged upright, and a dummy silicon substrate 60 is arranged upright between the two SOI substrates.

In this way, by placing each SOI substrate upright, the H ₂ O vapor generated from each SOI substrate can be moved in the direction of gravity, so that the H ₂ O generated from one SOI substrate is transferred to the other. It can be made difficult to adsorb on the SOI substrate. Note that the modified example of the second embodiment can be applied to the dummy silicon substrate 60.

<Other embodiments>
An adsorption layer made of a material having the property of adsorbing H ₂ O can also be formed on the substrate surface of the dummy substrate. For example, the adsorption layer can be formed of a material such as zirconium alloy, silica gel, alumina gel, silica / alumina gel, and zeolite. If this dummy substrate is used, H ₂ O generated from each SOI substrate can be adsorbed by the adsorption layer, so that excessive etching can be suppressed and etching accuracy can be improved.
Further, two or more of the above-described embodiments and modifications can be combined. Furthermore, the invention according to this application is not only the acceleration sensor described above, but also a pressure sensor, a flow rate sensor, etc., for example, a micro structure using MEMS (Micro-Electro-Mechanical Systems) etc. It is also effective in manufacturing structures as required.

30 ... Manufacturing equipment 31 ... Reaction chamber 32 ... Inlet port 33 ... Discharge port
41... First silicon layer 42.. Silicon oxide film 43.. Embedded oxide film
44 .. Second silicon layer 50.. Partition member
60 .. Dummy silicon substrate, 70 .. Tray (member), 80 .. Plate member,
90 .. Heater, S1 to S3 .. SOI substrate.

Claims (20)

A step of arranging a plurality of silicon substrates having a sacrificial layer in a reaction chamber so that the substrate surfaces face each other, and reacting an etching gas introduced into the reaction chamber with the sacrificial layer to dry-etch the sacrificial layer In the method for manufacturing a semiconductor device in which a reaction product containing H ₂ O is generated by the reaction described above,
The member having the property that at least H ₂ O of the reaction product does not easily permeate is disposed so as to partition a predetermined range between the silicon substrates of the plurality of silicon substrates disposed in the reaction chamber. A method for manufacturing a semiconductor device. A plurality of silicon substrates having a sacrificial layer on at least one substrate surface are arranged in a reaction chamber so that the substrate surfaces face each other, and an etching gas introduced into the reaction chamber reacts with the sacrificial layer to cause the sacrifice In a method for manufacturing a semiconductor device, which includes a step of dry etching a layer, and a reaction product containing H ₂ O is generated by the reaction described above.
A member for covering a predetermined range of each sacrificial layer of the silicon substrate disposed at least above the silicon substrate disposed at the bottom of the plurality of silicon substrates disposed in the reaction chamber, A method of manufacturing a semiconductor device, comprising a member having a property that at least H ₂ O of a reaction product is difficult to permeate.   2. The method of manufacturing a semiconductor device according to claim 1, wherein each of the silicon substrates has the sacrificial layer formed on at least one substrate surface.   4. The method of manufacturing a semiconductor device according to claim 1, wherein an area of the member facing the silicon substrate is larger than a substrate area of the silicon substrate.   5. The method of manufacturing a semiconductor device according to claim 4, wherein each of the silicon substrates is partitioned by the member, and the spaces formed by the partitions are not in communication with each other. The method for manufacturing a semiconductor device according to claim 1, wherein the member is a silicon substrate that does not generate H ₂ O by the reaction. The method of manufacturing a semiconductor device according to claim 1, wherein the member has a property of adsorbing the H ₂ O.   In the reaction chamber, an introduction port for introducing the etching gas into the reaction chamber is disposed above, and an exhaust port for discharging the reaction product from the reaction chamber is disposed below, and each of the reaction chambers 8. The method of manufacturing a semiconductor device according to claim 1, wherein the silicon substrate is arranged in a lateral direction with the substrate surfaces facing each other.   9. The method of manufacturing a semiconductor device according to claim 1, wherein a heater is built in the member.   The method of manufacturing a semiconductor device according to claim 1, wherein the sacrificial layer is a silicon oxide layer, and the etching gas contains anhydrous hydrofluoric acid gas. A reaction chamber in which a plurality of silicon substrates having a sacrificial layer can be arranged so that the substrate surfaces face each other, and the sacrificial layer is dried by reacting the etching gas introduced into the reaction chamber with the sacrificial layer. In a semiconductor device manufacturing apparatus configured to etch and generating a reaction product containing H ₂ O by the reaction described above,
The member having the property that at least H ₂ O of the reaction product does not easily permeate is disposed so as to partition a predetermined range between the silicon substrates of the plurality of silicon substrates disposed in the reaction chamber. A semiconductor device manufacturing apparatus. A reaction chamber in which a plurality of silicon substrates having a sacrificial layer on at least one substrate surface can be arranged so that the substrate surfaces face each other; and the etching gas introduced into the reaction chamber reacts with the sacrificial layer In the semiconductor device manufacturing apparatus, the sacrificial layer is configured to be dry-etched, and a reaction product containing H ₂ O is generated by the reaction.
A member for covering a predetermined range of each sacrificial layer of the silicon substrate disposed at least above the silicon substrate disposed at the bottom of the plurality of silicon substrates disposed in the reaction chamber, An apparatus for manufacturing a semiconductor device, comprising: a member having a property that it is difficult for at least H ₂ O of a reaction product to pass through.   12. The semiconductor device manufacturing apparatus according to claim 11, wherein each of the silicon substrates has the sacrificial layer formed on at least one substrate surface.   14. The semiconductor device manufacturing apparatus according to claim 11, wherein an area of the member facing the silicon substrate is larger than a substrate area of the silicon substrate.   The semiconductor device manufacturing apparatus according to claim 14, wherein the silicon substrates are partitioned by the member, and spaces formed by the partitions are not in communication with each other. The semiconductor device manufacturing apparatus according to claim 11, wherein the member is a silicon substrate that does not generate H ₂ O by the reaction. 16. The apparatus for manufacturing a semiconductor device according to claim 11, wherein the member has a property of adsorbing the H ₂ O.   In the reaction chamber, an introduction port for introducing the etching gas into the reaction chamber is disposed above, and an exhaust port for discharging the reaction product from the reaction chamber is disposed below, and each of the reaction chambers 18. The apparatus for manufacturing a semiconductor device according to claim 11, wherein the silicon substrate is arranged in a lateral direction with the substrate surfaces facing each other.   19. The semiconductor device manufacturing apparatus according to claim 11, wherein a heater is built in the member.   20. The semiconductor device manufacturing apparatus according to claim 11, wherein the sacrificial layer is a silicon oxide layer, and the etching gas contains anhydrous hydrofluoric acid gas.

Images