WO2011001778A1

WO2011001778A1 - Method for manufacturing silicon structure, device for manufacturing same, and program for manufacturing same

Info

Publication number: WO2011001778A1
Application number: PCT/JP2010/059343
Authority: WO
Inventors: 昌浩笹倉; 孝山本; 善幸野沢; 修次永野; 薫迫田; 智羽坂
Original assignee: 住友精密工業株式会社
Priority date: 2009-07-01
Filing date: 2010-06-02
Publication date: 2011-01-06
Also published as: TW201103087A; JPWO2011001778A1

Abstract

A method for manufacturing a silicon structure comprises a step for etching a silicon region of an object to be processed that includes the silicon region by alternately repeating a first step for converting an etching gas containing iodine fluoride into plasma by applying high-frequency power and a second step for converting an organic deposit forming gas into plasma by applying high-frequency power. As a result, a silicon structure having high perpendicularity and a good sidewall shape can be obtained by anisotropic dry etching of silicon which exerts less influence on global warming.

Description

Manufacturing method of silicon structure, manufacturing apparatus thereof, and manufacturing program thereof

The present invention relates to a method of manufacturing a silicon structure, a manufacturing apparatus thereof, and a manufacturing program thereof.

The technical field to which MEMS (Micro Electro Mechanical Systems) devices using silicon are applied is steadily expanding, and in recent years, the technology has been applied not only to microturbines and sensors but also to information communication and medical fields. Yes. One of the main elemental technologies that support this MEMS technology is anisotropic dry etching of silicon, and it can be said that the development of this elemental technology supports the development of MEMS technology.

Conventionally, among several existing anisotropic dry etching processes for silicon, a typical process proposed by a plurality of companies including the applicant of the present application is an etching process and a protective film forming process that are repeatedly performed. Process (for example, Patent Document 1). In the etching process of this process, sulfur hexafluoride (SF ₆ ) has been mainly used as an etching gas.

JP 2002-239014 A

In recent years, the technology of anisotropic dry etching of silicon has progressed dramatically, but on the other hand, the influence of greenhouse gases that have been used in the industry to carry out the process has begun to be concerned. . For example, the above-mentioned sulfur hexafluoride (SF ₆ ) has a very high so-called global warming potential (GWP), so finding an alternative gas to this gas and sending it to the market is an urgent task in consideration of the global environment. You can say that. However, since sulfur hexafluoride (SF ₆ ) has been used as a basic gas that supports anisotropic dry etching technology of silicon, it is not easy to find an alternative gas that can withstand market demands.

The present invention greatly contributes to the development of anisotropic dry etching technology for silicon that achieves high verticality and good sidewall shape by using a gas with a low warming coefficient instead of sulfur hexafluoride (SF ₆ ). It is.

In selecting an alternative gas for sulfur hexafluoride (SF ₆ ), the inventors, in addition to the etching characteristics of silicon due to the plasma formation of sulfur hexafluoride (SF ₆ ) alone, the above-described etching process and protective film formation We also paid attention to the relationship or compatibility with the organic deposit forming gas in the process where the process is repeated. As a result of the inventors' diligent research on a number of alternative gas candidates, a gas having such a small global warming potential (GWP) as to be almost negligible is a process in which the etching process and the protective film forming process are repeated. It was found that it was applicable and the present invention was completed.

One method of manufacturing a silicon structure according to the present invention includes a first step of converting an etching gas containing iodine fluoride into a plasma by applying a high frequency power, and a plasma of an organic deposit forming gas by applying the high frequency power. By alternately and repeatedly performing the second step, the silicon region in the workpiece including the silicon region is etched.

According to this silicon structure manufacturing method, an etching gas containing iodine fluoride is used instead of sulfur hexafluoride (SF ₆ ). As a result, an etching process in which an etching gas containing iodine fluoride is turned into plasma and a protective film forming process in which the organic deposit forming gas is turned into plasma are alternately repeated, thereby achieving high verticality and good sidewall shape. A silicon structure having

Another method of manufacturing a silicon structure according to the present invention is an etching including iodine fluoride by applying high-frequency power to an induction coil (hereinafter also simply referred to as a coil) using a dielectric coupled plasma etching apparatus. The first step of turning the gas into a plasma and the second step of turning the organic deposit forming gas into a plasma by applying high frequency power to the induction coil are alternately repeated, and the silicon region A step of etching the silicon region by applying high-frequency power to a stage electrode on which an object to be processed is placed.

According to this silicon structure manufacturing method, an etching gas containing iodine fluoride is used instead of sulfur hexafluoride (SF ₆ ). As a result, an etching process in which an etching gas containing iodine fluoride is turned into plasma by a dielectric-coupled plasma etching apparatus and a protective film forming process in which the organic deposit forming gas is turned into plasma by the apparatus are alternately repeated. As a result, a silicon structure having high verticality and good sidewall shape can be obtained.

In addition, the silicon structure manufacturing program of the present invention includes a first step of converting an etching gas containing iodine fluoride into plasma by applying high-frequency power, and an organic deposit forming gas by applying high-frequency power. The step of etching the silicon region in the object to be processed including the silicon region is performed by alternately and repeatedly performing the second step of converting the plasma into a plasma.

According to this silicon structure manufacturing program, an etching gas containing iodine fluoride is used in place of sulfur hexafluoride (SF ₆ ). As a result, an etching step in which the etching gas containing iodine fluoride is turned into plasma and a protective film forming step in which the organic deposit forming gas is turned into plasma are alternately repeated, thereby achieving high verticality and good sidewall shape. A silicon structure having

According to another aspect of the present invention, there is provided a silicon structure manufacturing program comprising: a first step of converting an etching gas containing iodine fluoride into plasma by applying high frequency power to an induction coil using a dielectric coupled plasma etching apparatus; The second step of converting the organic deposit forming gas into plasma by applying high-frequency power to the induction coil is alternately repeated, and the object to be processed including the silicon region is placed during the first step. A step of etching the silicon region by applying high frequency power to the stage electrode.

According to this silicon structure manufacturing program, an etching gas containing iodine fluoride is used in place of sulfur hexafluoride (SF ₆ ). As a result, the etching step in which the etching gas containing iodine fluoride is turned into plasma by the dielectric coupling type plasma etching apparatus and the protective film forming step in which the organic deposit forming gas is turned into plasma by the apparatus are alternately repeated. As a result, a silicon structure having high verticality and good sidewall shape can be obtained.

In addition, a silicon structure manufacturing apparatus according to the present invention includes a control unit that is controlled by any one of the silicon structure manufacturing programs described above or a recording medium that records any one of the silicon structure manufacturing programs. ing.

According to the manufacturing method, manufacturing apparatus, or manufacturing program of the present invention, the etching process in which the etching gas containing iodine fluoride is turned into plasma and the protective film forming process in which the organic deposit forming gas is turned into plasma are alternately repeated. By doing so, a silicon structure having high verticality and good sidewall shape can be obtained. In addition, iodine fluoride is a gas whose global warming potential (GWP) is small enough to be negligible compared to sulfur hexafluoride (SF ₆ ) (substantially, GWP is 0 (zero)). It can also make a significant contribution to the prevention of global warming.

It is sectional drawing which shows the structure of the manufacturing apparatus of the silicon structure in one embodiment of this invention. It is a schematic diagram which shows a part of final silicon structure in one embodiment of this invention. It is a section SEM (scanning electron microscope) photograph of a part of silicon structure 10 in one embodiment of the present invention. It is a figure which shows the time change of the flow volume of the protective film formation gas in the protective film formation process in one Embodiment of this invention. It is a figure which shows the time change of the flow volume of the etching gas in the etching process in one Embodiment of this invention. It is a figure which shows the time change of the induction coil application electric power in the protective film formation process in one Embodiment of this invention, and the induction coil application electric power in an etching process. It is a figure which shows the time change of the applied electric power to the stage electrode in the protective film formation process in one Embodiment of this invention, and the applied electric power to the stage electrode in an etching process. It is a figure which shows the time change of the chamber internal pressure in the protective film formation process in one Embodiment of this invention, and the chamber internal pressure in an etching process. It is a section SEM (scanning electron microscope) photograph of a part of silicon structure as an example which is not preferred. It is a manufacture flowchart of a silicon structure in one embodiment of the present invention. It is a section SEM (scanning electron microscope) photograph of a part of silicon structure 30 in other embodiments of the present invention. It is the cross-sectional SEM (scanning electron microscope) photograph which expanded a part (near opening part) of the silicon structure 30 in other embodiment of this invention.

DESCRIPTION OF

SYMBOLS

10,30 Silicon structure 12 Etching mask 14 Side wall 17 Residue 20 Chamber 21

Stage

22a,

22b Gas cylinder

23a, 23b Gas flow rate regulator 24 Inductive coil 25 First high frequency power source 26 Second high frequency power source 27 Vacuum pump 28 Exhaust flow rate regulator 29 Control unit 60 Computer 100 Silicon structure manufacturing apparatus

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, the elements of the present embodiment are not necessarily shown to scale. Moreover, in order to make each drawing easy to see, some reference numerals may be omitted. Unless otherwise specified, the flow rates of the following various gases indicate the flow rates in the standard state.

<First Embodiment>
FIG. 1 is a cross-sectional view showing an example of a device configuration of a silicon structure manufacturing apparatus 100 (hereinafter also simply referred to as a manufacturing apparatus 100) according to this embodiment. FIG. 2 is a schematic view showing a part of the final silicon structure of the present embodiment. In the present embodiment, the silicon substrate W that is an object to be processed is a single crystal silicon substrate, but is not limited to this. For example, the present embodiment can be applied even to a polycrystalline silicon substrate or an amorphous silicon substrate. Similarly, the present embodiment can be applied to an object to be processed (for example, a substrate) having a polycrystalline silicon layer or an amorphous silicon layer in part.

First, the configuration of the silicon structure manufacturing apparatus 100 shown in FIG. 1 will be described. A silicon substrate W to be etched (hereinafter also simply referred to as a substrate W) is placed on a stage 21 provided on the lower side of the chamber 20. The chamber 20 is supplied with at least one gas selected from an etching gas and an organic deposit forming gas (hereinafter also referred to as a protective film forming gas) from the

cylinders

22a and 22b through

gas flow controllers

23a and 23b, respectively. The These gases are turned into plasma by the induction coil 24 to which high frequency power is applied by the first high frequency power source 25. Thereafter, high-frequency power is applied to the stage 21 using the second high-frequency power source 26, so that the generated plasma is drawn into the silicon substrate W. Here, in the present embodiment, the power is applied to the stage 21 in a pulse form, in other words, in a state where the ON state and the OFF state of the application repeatedly appear at predetermined intervals. Further, a vacuum pump 27 is connected to the chamber 20 via an exhaust flow rate regulator 28 in order to decompress the inside of the chamber 20 and exhaust a gas generated after the process. The exhaust flow rate from the chamber 20 is changed by an exhaust flow rate regulator 28. The above-described gas

flow rate regulators

23a and 23b, the first high frequency power source 25, the second high frequency power source 26 capable of applying pulses, and the exhaust flow rate regulator 28 are controlled by a control unit 29. A known pressure gauge for measuring the pressure in the chamber 20 is not shown.

Next, the manufacturing process of the silicon structure 10 of this embodiment will be described. Note that the final silicon structure 10 of this embodiment has a trench structure having a width of about 3 μm and a depth of about 43 μm. FIG. 3 is a cross-sectional SEM (scanning electron microscope) photograph of a part of the silicon structure 10 described above. As shown in FIG. 3, it can be confirmed that good anisotropic dry etching was performed in this embodiment.

FIG. 4A is a diagram showing a change over time in the flow rate of the protective film forming gas in the protective film forming step of the present embodiment. Moreover, FIG. 4B is a figure which shows the time change of the flow volume of the etching gas in the etching process of this embodiment. Moreover, FIG. 4C is a figure which shows the time change of the induction coil application electric power in the protective film formation process of this embodiment, and the induction coil application electric power in an etching process. FIG. 4D is a diagram showing temporal changes in power applied to the stage electrode (also referred to as substrate applied power) in the protective film formation step of the present embodiment and power applied to the stage electrode in the etching step. In addition, FIG. 4E is a diagram showing the change over time in the chamber pressure in the protective film formation step and the chamber pressure in the etching step of the present embodiment. In order to make it easy to distinguish between the protective film forming step and the etching step in each figure, “D” representing the protective film forming step period and “E” representing the etching step period are shown. 4A to 4E, of course, show only a part of the time zone of the repeated protective film forming process or etching process.

Here, the anisotropic dry etching of silicon of the present embodiment employs a method of sequentially repeating a protective film forming process in which a protective film forming gas is introduced and an etching process in which an etching gas is introduced. In this embodiment, the protective film forming gas is C ₄ F ₈ and the etching gas is IF ₅ . In the present embodiment, a silicon substrate W on which a resist film is patterned as the etching mask 12 using a known photolithography technique is used.

In the manufacturing process of the silicon structure 10 of this embodiment, first, in the protective film forming process, the protective film forming gas is 200 sccm (also referred to as 200 mL / min.) For 2 seconds which is one unit processing time. The pressure in the chamber 20 is controlled to 8 Pa. A high frequency power of 13.56 MHz is applied to the induction coil 24 at 2600 W (for convenience, the second high frequency power may be used), but no power is applied to the stage 21. On the other hand, in the subsequent etching process, the etching gas is supplied at 200 sccm for 9 seconds, which is a unit processing time, and the pressure in the chamber 20 is controlled to 15 Pa. A high frequency power of 13.56 MHz is applied to the induction coil 24 at 2600 W (for convenience, it may be the first high frequency power), and a high frequency power of 13.56 MHz is applied to the stage 21 at 80 W (for convenience, the third high frequency power). It may be electric power.) Applied. As shown in FIGS. 4A to 4E, the above-described protective film forming step and etching step are continuously repeated for a predetermined time (about 50 minutes in the present embodiment), whereby the silicon structure 10 shown in FIG. Is formed.

Note that the etching rate under the anisotropic dry etching condition of this embodiment is about 0.9 μm / min. (Micrometers / minute). Further, the roughness of the side wall 14 in this embodiment (the length L in FIG. 2) is about 0.05 μm or less.

By the way, in this embodiment, iodine pentafluoride (IF ₅ ) whose global warming potential (GWP) is small enough to be ignored (substantially GWP is 0 (zero)) is used in the etching process. Yes. Therefore, as described above, the total amount of greenhouse gases discharged for forming the silicon structure 10 having a trench structure having a depth of about 43 μm and an aspect ratio of about 14 is significantly suppressed.

Further, according to the investigation by the inventors, when the process of the present embodiment is performed using iodine pentafluoride (IF ₅ ) as an etching gas, a protective film is formed as compared with the case where sulfur hexafluoride (SF ₆ ) is used. It was revealed that a good trench shape can be obtained even if the process time is short. Specifically, when the time length of the above-described etching process is set to 1, the time length of the protective film forming process is set to 0.11 or more and 0.33 or less, for example, as shown in FIG. A silicon structure with good, ie high verticality and good sidewall shape can be formed. Here, when the time length of the protective film forming step is less than 0.11, a part of the protective film formed on the surface of the side wall 14 of the etched trench structure is consumed or disappeared. There is an increased possibility that etching in the horizontal direction from 14 proceeds. Conversely, when the length of time of the protective film forming process exceeds 0.33, the protective film formed on the bottom surface of the trench structure is removed in the etching process and is not cut off, so that the bottom surface as shown in FIG. The possibility that the residue 17 is formed increases.

On the other hand, in the case of a process in which sulfur hexafluoride (SF ₆ ), which has substantially the same flow rate and etching rate of the protective film forming gas in the process of the present embodiment, is used as the etching gas, the time length of the etching process is set to 1. In addition, the length of time for the protective film forming step is greater than 0.33 and not greater than 0.66.

Therefore, if iodine pentafluoride (IF ₅ ) is used as an etching gas, a protective film is formed with a higher global warming potential (GWP) than when sulfur hexafluoride (SF ₆ ) is used as an etching gas. The amount of gas used can also be reduced. Although the detailed mechanism has not yet been clarified, when iodine pentafluoride (IF ₅ ) is adopted, I (iodine) formed on the surface of the object to be processed (for example, silicon substrate W) in the etching process. It is conceivable that some deposits included play a part in forming the protective film.

Incidentally, the control unit 29 provided in the above-described manufacturing apparatus 100 is connected to the computer 60. The computer 60 monitors or comprehensively controls the above process by a manufacturing program of the silicon structure 10 for executing the above anisotropic dry etching process. Hereinafter, a manufacturing program for the silicon structure 10 will be described with reference to a specific manufacturing flowchart. In this embodiment, the above-described manufacturing program is stored in a known recording medium such as an optical disk inserted into a hard disk drive in the computer 60 or an optical disk drive provided in the computer 60. The storage destination of is not limited to this. The manufacturing program can also monitor or control each of the processes described above via a known technique such as a local area network or an Internet line.

FIG. 6 is a manufacturing flowchart of the silicon structure 10 of the present embodiment.

As shown in FIG. 6, when the manufacturing program for the silicon structure 10 of the present embodiment is executed, first, in step S101, after the silicon substrate W is transferred into the chamber 20, the gas in the chamber 20 is exhausted. The Thereafter, in steps S102 to S104, the silicon substrate W is subjected to anisotropic dry etching in the chamber 20 under the above-described conditions.

Specifically, first, in step S102, a step of performing the protective film forming process of the present embodiment is executed. Next, a step of performing the etching process of the present embodiment is executed (step S103).

Thereafter, as shown in step S104, the program according to the present embodiment has the number of times that the respective steps of the step of performing the protective film forming step (step S102) and the step of performing the etching step (step S103) were initially set. It is determined whether or not it has been repeatedly executed. As a result, when the initially set number of times is repeatedly executed, the program of the present embodiment stops the anisotropic dry etching (step S105). On the other hand, when the initially set number of times is not repeatedly executed, a step of performing the protective film forming step and the etching step again is executed (steps S102 and S103).

After the anisotropic dry etching is stopped, the program of the present embodiment is brought into a state in which the silicon substrate W is taken out as shown in Step S105 (Step S106), and then the program of the present embodiment is finished. At this time, the substrate W may be directly taken out from the chamber after the chamber 20 is restored to the atmospheric pressure. However, the substrate W is connected via a loader / unloader (not shown) that can be connected to the chamber 20. It may be taken out.

The manufacturing program for the silicon structure 10 of the present embodiment integrally controls each condition in the etching process and the protective film forming process as described above. As a result of executing the manufacturing program of the present embodiment, a silicon structure having a high sidewall and a good sidewall shape is formed.

<Second Embodiment>
In the present embodiment, a silicon substrate provided with an etching mask formed so as to have an opening width of about 50 μm was etched under the same conditions as the anisotropic dry etching process conditions of the first embodiment. FIG. 7 is a cross-sectional SEM photograph of a part of the silicon structure 30 in the present embodiment. FIG. 8 is an enlarged cross-sectional SEM photograph of a part (near the opening) of the silicon structure 30 in the present embodiment.

As a result, as shown in FIG. 7, a silicon structure 30 having a trench structure with a width of about 50 μm and a depth of about 20 μm is obtained. Note that the etching rate under the anisotropic dry etching condition of this embodiment is about 2 μm / min. (Micrometers / minute). Further, the roughness of the side wall in this embodiment is about 0.1 μm as shown in FIG.

Incidentally, in the embodiments described above, the iodine pentafluoride (IF ₅₎ is used as the etching gas is not limited thereto. Instead of iodine pentafluoride (IF ₅ ), iodine trifluoride (IF ₃ ) and iodine heptafluoride (IF ₇ ) can also be applied to the above-described embodiments. In the above-described embodiment, C ₄ F ₈ is used as the protective film forming gas, but the present invention is not limited to this. Instead of C ₄ F ₈ , C ₅ F ₈ and C ₄ F ₆ can also be applied to the above-described embodiment. Further, the etching gas and the protective film forming gas do not need to be composed of only a single gas. For example, the etching gas may contain oxygen gas or argon gas in addition to iodine pentafluoride (IF ₅ ), and the protective film forming gas may contain oxygen gas in addition to C ₄ F ₈ or the like. good. However, sulfur hexafluoride (SF ₆ ) is not included in the etching gas.

Further, in each of the above-described embodiments, the object to be etched is a trench, but is not limited to this. Even if the object is a hole, substantially the same effect as the present invention can be obtained. Furthermore, in each of the above-described embodiments, there is one type of opening width (about 3 μm or about 50 μm), but the present invention is not limited to this. Even if there are two or more opening widths, the present invention can be applied.

Further, in each of the above-described embodiments, the protective film forming step is first performed, and then the etching step is performed. However, the order is not limited. For example, an etching process may be performed first and then a protective film forming process may be performed. Generally, when plasma is generated for the first time, it is necessary to introduce a gas to be plasma in advance for several seconds to 10 seconds in order to obtain a stable pressure for generating plasma in the chamber. There is. Then, it is better to introduce an etching gas with a low global warming potential (GWP) such as iodine pentafluoride (IF ₅ ) than to introduce a protective film forming gas with a high global warming potential (GWP) first. It can be said that it is preferable in considering the global environment. Moreover, even if an etching process is performed first and a protective film formation process is performed after that, about the shape of a silicon structure, there exists an effect similar to the above-mentioned embodiment. On the other hand, by performing the protective film formation step first, organic deposits are deposited on the etching mask before being exposed to the plasma of the etching gas, which can contribute to an improvement in the mask selectivity.

Also, the process immediately before stopping the anisotropic etching of the present embodiment is not limited to the etching process. Even if the protective film forming step is executed immediately before the anisotropic etching is stopped, the same effect as that of the present embodiment can be obtained. That is, based on the flowchart shown in FIG. 6, the program in which anisotropic etching is stopped (step S105) after step S102 is executed as a final process after step S102 and step S103 are repeated is also implemented. It can be applied as one variant of form.

In addition, in each of the above-described embodiments, high-frequency power is applied to the stage electrode only in the etching process, but the present invention is not limited to this. For example, in addition to the etching process, high-frequency power can be applied to the stage electrode also in the protective film forming process. Since high-frequency power is applied in the protective film forming step, formation of the protective film on the bottom surface of the etched region may be suppressed, which may rather contribute to an improvement in the etching rate.

Furthermore, although ICP (Inductively Coupled Plasma) is used as the plasma generation means in each of the above-described embodiments, the present invention is not limited to this. The same effects as those of the above-described embodiments can be obtained even when other high-density plasma, for example, CCP (Capacitive-Coupled Plasma) or ECR (Electron-Cyclotron Resonance Plasma) is used. As described above, modifications that exist within the scope of the present invention are also included in the claims.

Claims

By alternately and repeatedly performing a first step of converting an etching gas containing iodine fluoride into plasma by applying high-frequency power and a second step of converting organic deposit-forming gas into plasma by applying high-frequency power A method for manufacturing a silicon structure, comprising: etching the silicon region of an object to be processed including the silicon region.
A first step of converting an etching gas containing iodine fluoride into plasma by applying high-frequency power to the induction coil using a inductively coupled plasma etching apparatus, and forming organic deposits by applying high-frequency power to the induction coil The second step of turning the gas into plasma is alternately repeated, and during the first step, high-frequency power is applied to a stage electrode on which an object to be processed including the silicon region is placed. The manufacturing method of a silicon structure which has the process to etch.
The method for producing a silicon structure according to claim 1, wherein the iodine fluoride is iodine pentafluoride (IF 5 ).
3. The silicon structure according to claim 1, wherein the time length of the second step is 0.11 or more and 0.33 or less when the length of time of the first step is 1. 3. Production method.
By alternately and repeatedly performing a first step of converting an etching gas containing iodine fluoride into plasma by applying high-frequency power and a second step of converting organic deposit-forming gas into plasma by applying high-frequency power And a step of etching the silicon region of the workpiece including the silicon region.
A first step of converting an etching gas containing iodine fluoride into plasma by applying high-frequency power to the induction coil using a inductively coupled plasma etching apparatus, and forming organic deposits by applying high-frequency power to the induction coil The second step of turning the gas into plasma is alternately and repeatedly performed, and during the first step, high frequency power is applied to a stage electrode on which an object to be processed including the silicon region is placed. A silicon structure manufacturing program comprising the step of etching.
The manufacturing program for a silicon structure according to claim 5 or 6, wherein the iodine fluoride is iodine pentafluoride (IF 5 ).
7. The silicon structure according to claim 5, wherein the time length of the second step is 0.11 or more and 0.33 or less when the length of time of the first step is 1. 7. Manufacturing program.
A recording medium on which the manufacturing program according to claim 5 or 6 is recorded.
A silicon structure manufacturing apparatus comprising a control unit controlled by the manufacturing program according to claim 5.
An apparatus for manufacturing a silicon structure, comprising: a control unit controlled by the recording medium according to claim 9.