JP6225005B2 - Laminated film and manufacturing method thereof - Google Patents

Description

  The present invention relates to a laminated film and a manufacturing method thereof, and more particularly to a laminated film of an organic material layer and a protected layer and a manufacturing method thereof.

  In MEMS (Micro Electro Mechanical Systems) or NEMS (Nano Electro Mechanical Systems), which are representative examples of microstructures, a special shape of a base material is obtained by using a part of the formed silicon oxide layer as a sacrificial layer. (Movable parts, etc.) are realized. As miniaturization in MEMS or NEMS is progressing steadily, it is indispensable for the development of miniaturization technology to improve the film quality and to form a film with high moldability and controllability.

  Until now, many film forming techniques and processing techniques for the films have been disclosed. For example, a technique is disclosed in which an amorphous carbon film is formed in order to prevent copper (Cu) as an electrode layer from diffusing into a low-k film stacked on the electrode layer (Patent Document 1). ).

  In the past, one method has been proposed for use as a protective layer during the manufacture of semiconductors and MEMS devices (Patent Document 2). The composition proposed in U.S. Patent No. 6,057,031 contains a cycloolefin copolymer dispersed or dissolved in a solvent system and is used to form a layer that protects the substrate during acid etching and other processing and handling. Is disclosed.

JP 2008-182174 A Special table 2012-524405 gazette

  As described above, in the development of various devices in MEMS or NEMS, improvement in controllability including thin film formation technology and pattern processing is strongly desired.

  In particular, in a microstructure represented by MEMS or NEMS, when a sacrificial layer etching means using a liquid is employed, the sacrificial layer region is sandwiched by the surface tension of the liquid, particularly when the sacrificial layer is thin. There may be a problem that the structural portions cannot be separated and remain in contact with each other. Therefore, in order not to cause such a problem, it is necessary to employ an etching means using gas or plasma.

For example, when etching a silicon oxide layer with a gas among the above insulating layers, vapor of hydrogen fluoride is used. Conventionally, an amorphous silicon (a-Si) layer or tungsten silicide is used as a protective material having low permeability to hydrogen fluoride vapor in order to prevent the insulating layer in a region different from an etching target from being exposed to hydrogen fluoride vapor. Inorganic materials such as (WSi) layers or aluminum oxide (Al ₂ O ₃ ) have been employed. However, when the above-mentioned inorganic material is removed after etching the silicon oxide layer with a gas, the etching rate selection ratio with silicon that is a base material of a structure that is generally employed cannot be sufficiently obtained. It was virtually impossible to remove the inorganic material.

  On the other hand, it is preferable to use an organic material as the protective material because it can be easily removed by a subsequent treatment using oxygen plasma. However, for example, when a known resist film is used as the protective material, if the resist layer has a thickness of several μm, the hydrogen fluoride vapor will pass through the resist layer, so that it functions as a protective material. Will not be fulfilled. On the other hand, even if a resist film having a thickness of 100 μm or more (for example, 200 μm) is formed on the protective layer, it does not have a shielding effect against long-time exposure to hydrogen fluoride vapor. Therefore, the known resist layer is difficult to provide a sufficient shielding effect for the protected layer. In the invention described in the above-mentioned Patent Document 1, since the amorphous carbon film is provided as a barrier layer to prevent copper diffusion, the idea regarding the removal of the amorphous carbon film is not suggested or disclosed at all. It has not been. In addition, even with the resist described in Patent Document 2, which is said to be resistant to hydrogen fluoride vapor or shielded, the hydrogen fluoride vapor resistant or shielded for a long time. Has not been confirmed yet. In particular, in the MEMS (or NEMS) field, since it is common to require a processing time of 1 hour or more, a protective material as an organic material that can withstand long-time processing is strongly demanded in the industry. By the way.

  The present invention greatly contributes to the realization of the ease of removing the protective material covering the protected layer, which has a shielding effect on the vapor of hydrogen fluoride.

  The inventor of the present application considers that if the above-described protective material can be removed more easily than the conventional material after finishing its role, it is possible to realize the speed of processing after processing the protective layer, and earnest research And worked on the analysis. As a result, the inventor of the present application laminated at least one layer selected from the group consisting of an amorphous carbon layer and a diamond-like carbon layer, which are organic layers, on the protected layer, thereby fluorinating the protected layer. It has been found that a protective material that exhibits an effect of shielding hydrogen vapor can be realized, and that the protective material can be easily removed by a subsequent treatment using oxygen plasma. The laminated film and the manufacturing method thereof of the present invention were created based on the above viewpoint.

  One laminated film of the present invention includes at least one second layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer formed so as to cover a part of the first layer by a CVD method or a PVD method. I have. Further, in this laminated film, when the above-mentioned second layer and the first layer in a region different from the above-mentioned part are exposed to hydrogen fluoride vapor, the first layer in a region different from the part of the first layer. Is more than 800 times faster than the etching rate of a part of the first layer.

  According to this laminated film, the first layer as the protected layer covered by the second layer which is at least one organic material layer selected from the group of the amorphous carbon layer and the diamond-like carbon layer, and the hydrogen fluoride A sufficient difference in etching rate with the first layer exposed to the vapor can be secured. As a result, after the damage (etching) of the first layer as the protected layer covered by the second layer is prevented or suppressed with high accuracy, the first layer exposed to the hydrogen fluoride vapor is etched with high accuracy. Can be realized. Further, since the organic layer constituting the second layer covers the layer to be protected, when the second layer is removed after the etching of a part of the first layer is completed, treatment with a liquid is performed. Therefore, the second layer can be removed by an easy, rapid and low-cost means such as treatment with oxygen plasma. In addition, according to this laminated film, silicon, which is a base material of a structure that is generally employed, or silicon nitride that can be one of the members of the structure, when performing the treatment by the oxygen plasma treatment A sufficient difference in etching rate (selectivity) can be obtained.

  Moreover, the manufacturing method of one laminated film of this invention is at least 1 type of 2nd selected from the group of an amorphous carbon layer and a diamond-like carbon layer so that a part of 1st layer may be covered by CVD method or PVD method. An organic layer forming step for forming a layer (second layer forming step), and an exposing step for exposing the second layer and a first layer in a region different from the second layer to a part of the second layer. . In addition, in the method for manufacturing the laminated film, in the exposure step, the etching rate of the first layer in a region different from the part described above is 800 times or more faster than the etching rate of the part of the first layer. .

  According to this method for producing a laminated film, the second layer, which is at least one organic material layer selected from the group of the amorphous carbon layer and the diamond-like carbon layer formed in the organic material layer forming step, is used as the second layer. A sufficient difference in etching rate between the first layer as the protection layer covered by the layer and the first layer exposed to the hydrogen fluoride vapor can be secured. As a result, in the above-described exposure step, damage (etching) of the first layer as the protection layer covered by the second layer is prevented or suppressed with high accuracy, and then exposed to the hydrogen fluoride vapor. One layer of highly accurate etching can be realized. Further, since the organic layer constituting the second layer covers the first layer, for example, oxygen can be used without removing the second layer after the exposure step, without requiring treatment with a liquid. The second layer can be removed by an easy, rapid, and low-cost means called plasma treatment. In addition, according to this method for manufacturing a laminated film, silicon or a member of the structure, which is a base material of a structure that is generally employed, is used when performing the treatment by the treatment with oxygen plasma. A sufficient difference (selectivity) in etching rate from the obtained silicon nitride can be obtained.

  In addition, since the 1st layer in this application should just be a layer which is going to protect from exposure of the vapor | steam of hydrogen fluoride by the above-mentioned organic substance layer, it is not limited to the material thru | or function of the layer. The first layer of the present application includes not only a single layer but also a plurality of layers.

  According to one laminated film of the present invention, a protective layer covered with at least one organic material layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer, and a layer exposed to hydrogen fluoride vapor A sufficient difference in etching rate can be secured. As a result, it is possible to achieve highly accurate etching of the layer exposed to the hydrogen fluoride vapor while preventing or suppressing damage to the protected layer with high accuracy. Further, the organic layer covering the protected layer can be removed by an easy, rapid and low-cost means such as treatment with oxygen plasma.

  Moreover, according to the manufacturing method of one laminated film of this invention, the layer to be protected which the organic substance layer formed in the above-mentioned organic substance layer formation process covers, and the layer exposed to the vapor of hydrogen fluoride, A sufficient difference in etching rate can be secured. As a result, in the above-described exposure step, it is possible to achieve highly accurate etching of the layer exposed to the hydrogen fluoride vapor while preventing or suppressing damage to the protected layer with high accuracy. Further, the organic layer covering the protected layer can be removed by an easy, rapid and low-cost means such as treatment with oxygen plasma.

It is a partial cross section figure which shows the structure of the manufacturing apparatus of the laminated film in one embodiment of this invention. In one embodiment of the present invention, a laminated film (a) having a thickness of about 70 nm as a second layer, which is an organic material layer on the first layer as a protected layer, and a laminated film having a thickness of about 500 nm as the second layer It is a cross-sectional SEM photograph which shows a film | membrane (b). It is a section lineblock diagram showing an example of the structure of the lamination film in one embodiment of the present invention. It is a section lineblock diagram showing an example of the structure of the lamination film in one embodiment of the present invention. It is a section lineblock diagram showing an example of the structure of the lamination film in one embodiment of the present invention. In one embodiment of the present invention, a laminated film having a second layer thickness of about 70 nm, which is an organic layer on the first layer as a protective layer, after exposure to hydrogen fluoride vapor and ethanol vapor for 3 hours It is a cross-sectional SEM photograph which shows (a) and the laminated film (b) whose thickness of this 2nd layer is about 500 nm.

  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. In the drawings, the elements of the present embodiment are not necessarily shown according to the scale. Moreover, the flow rates of the following various gases indicate the flow rates in the standard state.

<First Embodiment>
FIG. 1 is a partial cross-sectional view illustrating a configuration of a laminated film manufacturing apparatus 100 according to the present embodiment. Since this drawing is a schematic diagram, peripheral devices including a part of a known gas supply mechanism and a part of an exhaust mechanism are omitted.

An object to be processed (in this application, “silicon substrate”) 10 transferred by a substrate transfer chamber (not shown) is placed on a stage 41 provided near the center of the chamber 40. The object 10 and the inside of the chamber 40 are heated by heaters 44 a and 44 b provided on the outer wall of the chamber 40. A gas cylinder 42a of methane (CH ₄ ) gas is connected to the chamber 40 via a gas flow rate regulator 43a, and a gas cylinder 42b of rare gas (typically argon (Ar) gas) is connected to the gas flow rate regulator. 43b is connected.

  Further, the high frequency power supply 46 a applies high frequency power to the shower head gas introduction unit 45 to turn the gas discharged from the shower head gas introduction unit 45 into plasma. The generated plasma is subjected to the object to be processed 10 (more specifically, the object to be protected formed on the object to be processed 10) placed on the stage 41 to which high frequency power is applied by the high frequency power supply 46 b as necessary. To the first layer 20 as a layer). In the present embodiment, an amorphous carbon layer and diamond-like carbon that are examples of a second layer (hereinafter simply referred to as “second layer”) 30 that is an organic layer on a silicon oxide layer that is an example of the first layer 20. A step of forming at least one layer selected from the group of layers is performed. As a result, a laminated film 90 composed of the first layer 20 and the second layer 30 is formed.

  The shower head gas introduction part 45 is electrically insulated from the chamber 40 by a ring-shaped sealing material S. The stage 41 is also electrically insulated from the chamber 40 by the ring-shaped sealing material S. In addition, a vacuum pump 47 is connected to the chamber 40 via an exhaust flow rate regulator 48 in order to depressurize the chamber 40 and exhaust gas generated after the process. Further, the exhaust flow rate from the chamber 40 is changed by an exhaust flow rate regulator 48. The gas flow regulators 43a and 43b, the heaters 44a and 44b, the first high-frequency power supply 46a, the second high-frequency power supply 46b, and the exhaust flow regulator 48 are controlled by the control unit 49.

  Incidentally, the control unit 49 provided in the laminated film manufacturing apparatus 100 in the present embodiment is connected to the computer 60. The computer 60 monitors or comprehensively controls the above-described process by a laminated film manufacturing program for executing the above-described process. In the present embodiment, the 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 is not limited to this. For example, a part or all of the manufacturing program may be stored in the control unit 49 provided in the process chamber in the present embodiment. 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.

  Next, a process in the chamber 40 of the laminated film manufacturing apparatus 100 in this embodiment will be described.

<Formation process of organic layer>
In the present embodiment, as described above, at least one layer selected from the group of the amorphous carbon layer that is an example of the second layer 30 and the diamond-like carbon layer on the silicon oxide layer that is an example of the first layer 20. The process of forming is performed. In the present embodiment, the silicon oxide layer as the first layer 20 can be formed by a known method (for example, a plasma CVD method).

  The heated object 10 and the first layer 20 on the object 10 are exposed to plasma formed from methane gas using the chamber 40. Specifically, 100 sccm of methane gas is supplied to the chamber 40 until the pressure in the chamber 40 reaches 50 Pa. Further, the heater 44b is heated until the temperature of the stage 41 reaches 350 ° C. Thereafter, 50 W of high frequency power (the output frequency of the present embodiment is 13.56 MHz) is applied to the showerhead gas introduction unit 45, and 400 W of high frequency power (the output frequency of the present embodiment is 380 kHz) is applied to the stage 41. Is applied. In the present embodiment, the second layer 30 having a thickness of about 50 nm to about 500 nm is formed by performing the formation process of the second layer 30 under the above plasma conditions for 2 minutes to 20 minutes. As a result, a laminated film 90 of the first layer 20 and the second layer 30 is formed. FIG. 2 shows a laminated film (a) in which the thickness of the second layer 30 on the first layer 20 is about 70 nm and a laminated film (b) in which the thickness of the second layer 30 is about 500 nm in this embodiment. It is a cross-sectional SEM photograph shown.

  Note that the second layer 30 of the present embodiment is an organic layer, specifically a carbon layer. More specifically, the second layer 30 is at least one layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer. Therefore, the second layer 30 of the present embodiment is a carbon layer including at least an amorphous carbon layer or a diamond-like carbon layer, and is not limited to either the amorphous carbon layer or the diamond-like carbon layer.

  Further, the first layer 20 of the present embodiment is a silicon oxide layer, but the first layer 20 is not limited to the silicon oxide layer. For example, it is selected from the group consisting of an insulating layer including a silicon oxynitride layer or a silicon nitride layer, a conductive layer including titanium and titanium nitride, and an organic film layer including a resin layer, which is not resistant to hydrogen fluoride vapor. May be included in the first layer 20 of the present embodiment.

  Moreover, although the 2nd layer 30 is formed in the laminated film 90 of this embodiment on the whole surface of the 1st layer 20, the laminated film 90 of this embodiment is not limited to such an aspect. For example, even if the laminated film 90 includes the second layer 30 on the first layer 20 on which the pattern formed relatively easily by a known means as shown in FIG. Can be played. When the laminated film 90 is exposed to hydrogen fluoride vapor, the first layer 20 not covered by the second layer 30 is etched by the hydrogen fluoride vapor. In the present embodiment, since a part of the first layer 20 is covered with the second layer 30, the first layer covered with the second layer 30 when the laminated film 90 is exposed to hydrogen fluoride vapor. A sufficient difference in etching rate between the first layer 20 exposed to the vapor of hydrogen fluoride and 20 can be ensured.

  More specifically, the etching rate of the first layer 20 exposed to the vapor of hydrogen fluoride is the etching rate of the first layer 20 covered by the second layer 30 under the formation conditions of the second layer 30 in the present embodiment. It was found that the speed was 800 times or more. Moreover, it turned out that the adhesiveness of the 2nd layer 30 and the 1st layer 20 is also favorable. As a result, it is possible to achieve highly accurate etching of the protected layer exposed to the hydrogen fluoride vapor while preventing or suppressing damage (etching) of the protected layer covered with the organic material layer. By obtaining the above-described difference in etching rate, for example, even if the silicon oxide layer isotropically etched by the hydrogen fluoride vapor is the first layer 20, it is almost covered by the second layer 30. It is worth noting that the first layer 20 can be etched without erosion.

  FIG. 4 shows an example in which the laminated film 90 of this embodiment is used in an SOI substrate including the first layer 21 as a buried silicon oxide layer. In this embodiment, the first layer 21 as a buried silicon oxide layer formed between the object to be processed 10 and the active layer 11 is a so-called sacrificial layer. The first layer 21 as the buried silicon oxide layer is etched by being exposed to hydrogen fluoride vapor and ethanol vapor. On the other hand, the silicon oxide layer that is the first layer 20 as the protection layer formed on the back side of the object to be processed 10 is covered with the second layer 30. As a result, even if the laminated film 90 formed by the first layer 20 and the second layer 30 is exposed to hydrogen fluoride vapor and ethanol vapor on both surfaces of the object 10 to be treated, The first layer 20 is protected by resistance to hydrogen fluoride vapor and ethanol vapor. Here, ethanol vapor and / or water vapor may be added as an auxiliary agent for adsorbing hydrogen fluoride vapor on the buried silicon oxide layer (first layer) 21 to be etched. Further, ethanol vapor and / or water vapor is employed as a material that does not affect the second layer 30 by chemical change or the like. In this embodiment, the laminated film 90 is exposed to ethanol vapor as well as hydrogen fluoride vapor. The ethanol vapor does not contribute to the etching of the first layer 21 as the buried silicon oxide layer, but keeps the object 10 and the active layer 11 separated after the buried silicon oxide layer is removed. Contribute. In other embodiments in which ethanol vapor is introduced, the ethanol vapor may have a similar effect.

  Here, in the embodiment shown in FIG. 4, if the buried silicon oxide layer 21 is removed by employing a liquid etching means, the active layer 11 sandwiched between the buried silicon oxide layer 21 regions by the surface tension of the liquid and the object to be processed There may be a problem of staying in contact with the body 10. However, as described in the present embodiment, when the buried silicon oxide layer 21 is etched using vapor (gas) instead of liquid, the above-described problem hardly occurs. By this effect, it is possible to achieve further enhancement of the miniaturization of various devices (such as various sensors or analysis devices) in the field of MEMS or NEMS and improvement of the yield with high accuracy. It should be noted that, as in the present embodiment, it is also possible to employ the second layer 30 protecting the silicon oxide layer (the first layer 20 in FIG. 4) on the back side, which is a part of the first layers 20 and 21 in particular. It is one mode.

  FIG. 5 shows another example in which the laminated film 90 of this embodiment is used in an SOI substrate including the buried silicon oxide layer 21. Similar to the embodiment shown in FIG. 4, the first layer 21 as a buried silicon oxide layer formed between the workpiece 10 and the active layer 11 is a so-called sacrificial layer. The first layer 21 as the buried silicon oxide layer is etched by being exposed to hydrogen fluoride vapor and ethanol vapor. On the other hand, in this embodiment, the first layer 50 as the protected layer covered by the second layer 30 is a silicon nitride layer that covers the electrode 15 disposed on the active layer 11. As a result, even if the laminated film 90 formed by the first layer 50 and the second layer 30 is exposed to hydrogen fluoride vapor and ethanol vapor, the hydrogen fluoride vapor and ethanol of the second layer 30 are exposed. The first layer 50 is protected by resistance to steam.

  4 and 5, the first layer as the protected layer is formed of the same material as the first layer exposed to hydrogen fluoride vapor and ethanol vapor. There is no need, and there is no need to be arranged in the same hierarchy. In addition, a first layer as a protection layer is arranged on the back side of the object to be processed 10, and a first layer exposed to hydrogen fluoride vapor and ethanol vapor is on the surface side of the object to be processed 10. Arrangement is also an aspect that can be adopted in the present embodiment.

  As described above, the laminated film of the present embodiment can be appropriately employed in various devices or structures that bear a part of the devices. In any structure, the organic material can be removed from the second layer 30 that has finished the role of protecting the first layers 20 and 50 by an easy, rapid, and low-cost means such as treatment with oxygen plasma. It becomes.

<Modification of First Embodiment>

  In the first embodiment described above, the temperature of the stage 41 is set to 350 ° C., but the temperature of the stage 41 is not limited to that temperature. For example, when the temperature of the stage 41 is 70 ° C. or higher, the processing time or the thickness of the formed second layer 30 is different, but the same effect as the effect of the first embodiment or a part of the effect is exhibited. obtain. However, the inventor of the present application has found that, as the temperature of the stage 41 is higher, the resistance of the second layer 30 to the hydrogen fluoride vapor and the ethanol vapor increases as the temperature of the stage 41 increases. Therefore, from the viewpoint of increasing the resistance to hydrogen fluoride vapor and ethanol vapor with high accuracy, it is a more preferable aspect that the temperature of the stage 41 is 200 ° C. or higher. Further, the upper limit of the temperature of the stage 41 is not particularly limited, but the temperature of the stage 41 is preferably set to 400 ° C. or less from the viewpoint of avoiding high cost and a long process.

<Second Embodiment>
The laminated film and the manufacturing method thereof of the present embodiment are the same as those of the first embodiment except that a part of the conditions for forming the second layer 30 in the first embodiment is different. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

<Formation process of organic layer>
Also in the present embodiment, at least one layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer as an example of the second layer 30 on the silicon oxide layer that is the first layer 20 as the protected layer. The process of forming is performed.

  The heated object 10 and the first layer 20 on the object 10 are exposed to plasma formed from methane gas using the chamber 40. Specifically, 100 sccm of methane gas and 500 sccm of argon gas are supplied to the chamber 40 until the pressure in the chamber 40 reaches 50 Pa. Next, the heater 44b is heated until the temperature of the stage 41 reaches 70 ° C. Thereafter, 150 W of high-frequency power (the output frequency of the present embodiment is 380 kHz) is applied to the showerhead gas introduction unit 45, and no high-frequency power is applied to the stage 41. In the present embodiment, the second layer 30 having a thickness of about 50 nm to about 500 nm is formed by performing the formation process of the second layer 30 under the above plasma conditions for 3 minutes to 30 minutes. As a result, a laminated film of the first layer 20 and the second layer 30 is formed.

  In any of the laminated films of each of the embodiments described above, the second layer 30 is removed by performing an oxygen plasma process (so-called ashing process) after etching with hydrogen fluoride vapor and ethanol vapor is finished. We were able to.

<Evaluation of laminated film>
The inventor of the present application is the first when the laminated film formed in each of the above-described embodiments disposed in a sealed chamber capable of supplying and exhausting gas is exposed to hydrogen fluoride vapor and ethanol vapor for a predetermined time. The change of the state of the 2nd layer 30 and the 1st layer 20 as a to-be-protected layer was observed. The first layer 20 in this evaluation is a silicon oxide film formed by a known thermal oxidation method. Moreover, the thickness of the 2nd layer 30 and the 1st layer 20 was measured with the optical interference type film thickness measuring apparatus.

Specific exposure conditions are as follows. First, the flow rate of the vapor of hydrogen fluoride introduced into the chamber was 700 sccm, and the vapor of ethanol was 265 sccm. In addition, nitrogen (N ₂ ) at a flow rate of 900 sccm was introduced together with hydrogen fluoride vapor and ethanol vapor. The pressure in the chamber was about 30 kPa. As a reference example, the etching rate of the silicon oxide film by the above-described thermal oxidation method exposed to various gases at these flow conditions is 240 nm / min. It was confirmed that. The states of the second layer 30 and the first layer 20 were performed by observing a cross-sectional SEM photograph.

  For the laminated film of the first embodiment in which the temperature of the stage 41 is 350 ° C., regardless of whether the initial thickness of the second layer 30 is about 70 nm or the initial thickness of about 500 nm, No substantial decrease in thickness was observed even after 3 hours from the start of exposure. Moreover, the damage of the 2nd layer 30 and the 1st layer 20 as a to-be-protected layer was not seen. FIG. 6 shows a laminated film (a) in which the thickness of the organic layer on the protected layer is about 70 nm after exposure to hydrogen fluoride vapor and ethanol vapor for 3 hours in the first embodiment; It is a cross-sectional SEM photograph which shows the laminated film (b) whose thickness of the layer 30 is about 500 nm. As described above, even when the thickness of the second layer 30 is not less than 50 nm and not more than 100 nm, a substantial decrease in thickness is observed even after 3 hours from the start of exposure under the exposure conditions described above. The absence of the second layer 30 is a very preferable aspect from the viewpoint of reducing the formation time of the second layer 30 and the manufacturing cost.

  However, for the laminated film of the second embodiment in which the temperature of the stage 41 is 70 ° C., when the initial thickness of the second layer 30 is about 500 nm, the result is the same as the result of the laminated film of the first embodiment. However, when the initial thickness of the second layer 30 was about 70 nm, it was confirmed that the second layer 30 was damaged in some way. Further, when the initial thickness of the second layer 30 was about 70 nm, the thickness was reduced to about 50 nm after 3 hours of exposure. In addition, when the initial thickness of the second layer 30 was about 70 nm, the thickness of the first layer 20 as the protected layer was reduced from the initial 1.124 μm to 1.072 μm. As a result, the etching rate of the first layer 20 as the protected layer at this time is 0.29 nm / min. Therefore, based on the etching rate (240 nm / min.) Of the silicon oxide film by the thermal oxidation method of the reference example described above, the etching rate of the first layer 20 when not covered by the second layer 30 is It can be seen that it is at least 800 times faster than that of the first layer 20 covered by the two layers 30.

  Therefore, it is preferable to apply high-frequency power to the stage 41 as well as high-frequency power to the showerhead gas introduction unit 45 from the viewpoint of increasing the resistance of the second layer 30 to hydrogen fluoride vapor and ethanol vapor. This is one aspect. However, it is worthy to note that any of the above laminated films has resistance to exposure for 3 hours under the above-mentioned exposure conditions. According to the research and analysis of the present inventor, the etching rate of the first layer 20 that is not covered by the second layer 30 is higher than the etching rate of the first layer 20 that is covered by the second layer 30. If the speed is 800 times or more, the damage (etching) of the first layer 20 as the protection layer covered by the second layer 30 is prevented or suppressed, and then exposed to hydrogen fluoride vapor and ethanol vapor. Highly accurate etching of the one layer 20 can be realized.

  By the way, although the value of the applied power to the stage 41 is not particularly limited, from the viewpoint of further enhancing the resistance of the second layer 30 to hydrogen fluoride vapor and ethanol vapor, the first layer 20 as the protection layer is It is preferable that the second layer 30 is formed by applying electric power of 50 W or more and 1000 W or less to the stage on which the formed workpiece 10 is placed.

  Furthermore, as a result of investigation by the inventor, the above-described exposure was performed for the laminated film of the first embodiment regardless of whether the initial thickness of the second layer 30 was about 70 nm or about 500 nm. Under the conditions, there was almost no decrease in thickness even after 24 hours from the start of exposure. Further, there was no or limited decrease in the thickness of the first layer 20 as the protected layer. As described above, the formation of the second layer 30 that can withstand exposure for 24 hours is due to the process of the first layer 20 that can be etched by hydrogen fluoride vapor and ethanol vapor. In addition, the degree of structural freedom is greatly increased.

<Other embodiments>
By the way, in the above-mentioned embodiment, although the control part 49 was directly connected to the exhaust gas flow regulator 38 grade | etc., The aspect of each above-mentioned embodiment is not limited to such a structure. For example, a mode in which the control unit 49 is connected to the exhaust flow rate regulator 48 or the like indirectly through a known technology such as a local area network or an Internet line may be adopted in other embodiments described above. It can be included in one embodiment.

  In each of the above-described embodiments, at least one second layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer is formed using methane gas as a raw material gas. The gas produced is not limited to methane gas. For example, even if a hydrocarbon gas typified by acetylene or an organic solvent composed only of carbon and hydrogen typified by acetone or xylene is used instead of methane gas, it is equivalent to at least a part of the effect of the above embodiment. An effect can be obtained.

  In each of the above-described embodiments, the object to be processed 10 is a silicon substrate. However, the object to be processed in each of the above-described embodiments is not limited to a silicon substrate. For example, even if the object to be processed is a glass substrate or a silicon substrate bonded to the glass substrate, effects similar to or at least part of the effects of the above-described embodiments can be achieved.

  Furthermore, in each of the above-described embodiments, a plasma CVD apparatus is used in forming the organic material layer (second layer 30). However, the CVD apparatus employed in each of the above-described embodiments is not limited to the plasma CVD apparatus. . For example, even when a thermal CVD apparatus is employed instead of the plasma CVD apparatus, the same effects as those of the above-described embodiments can be achieved. Moreover, although the parallel plate type | mold (CCP; Capacitive-Coupled Plasma) was used in the above-mentioned embodiment as a plasma production | generation means, each above-mentioned embodiment is not limited to this. The use of other high-density plasma, for example, ICP (Inductively-Coupled Plasma), ECR (Electron-Cyclotron Resonance Plasma), or LP-CVD (Low Pressure CVD), is equivalent to at least one of the effects of the above-described embodiment. The effect of a part can be acquired. Moreover, although formation of the organic substance layer by CVD method was demonstrated in the above-mentioned embodiment, the above-mentioned embodiment is not limited to formation by CVD method. For example, even when the organic material layer is formed by the PVD method, the effect equivalent to or at least a part of the effect of the above-described embodiment can be obtained.

  The disclosure of each of the above-described embodiments is described for explaining the embodiments, and is not described for limiting the present invention. In addition, modifications within the scope of the present invention including other combinations of the embodiments are also included in the claims.

DESCRIPTION OF SYMBOLS 10 To-be-processed object 11 Active layer 15 Electrode 20,50 1st layer 21 1st layer (buried silicon oxide layer)
30 Second layer (organic layer)
41 stages 42a, 42b gas cylinders 43a, 43b gas flow rate regulator 40 chamber 46a first high frequency power source 46b second high frequency power source 47 vacuum pump 48 exhaust flow rate regulator 49 control unit 44a, 44b heater 45 shower head gas introduction unit 90 laminated film 100 Multilayer film manufacturing equipment

Claims (7)

At least one second layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer formed so as to cover a part of the first layer by a CVD method or a PVD method, and a second region different from the part. When one layer is exposed to hydrogen fluoride vapor,
The etching rate of the first layer in a region different from the part is 800 times or more faster than the etching rate of the part of the first layer;
Laminated film. The thickness of the second layer is 50 nm or more and 100 nm or less,
The laminated film according to claim 1. A part of the first layer is a buried silicon oxide layer in an SOI substrate;
The laminated film according to claim 1 or 2. An organic layer forming step of forming at least one second layer selected from the group of an amorphous carbon layer and a diamond-like carbon layer so as to cover a part of the first layer by a CVD method or a PVD method;
Exposing the second layer and the first layer in a region different from the portion to a vapor of hydrogen fluoride,
In the exposing step, the etching rate of the first layer in a region different from the part is 800 times or more faster than the etching rate of the part of the first layer.
Manufacturing method of laminated film. The thickness of the second layer is 50 nm or more and 100 nm or less,
The manufacturing method of the laminated film of Claim 4 . The first layer is a buried silicon oxide layer in an SOI substrate;
The manufacturing method of the laminated film of Claim 4 or Claim 5 . The second layer is formed by applying electric power of 50 W or more and 1000 W or less to the stage on which the object to be processed on which the first layer is formed is placed.
The manufacturing method of the laminated film of any one of Claim 4 thru | or 6 .