KR100583429B1 - Flexible film with single crystal and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a single crystal flexible film made from a semiconductor single crystal wafer and a method of manufacturing the same. That is, an SOI wafer composed of a base wafer, an investment insulating film, and a single crystal layer is thinned by various wafer thinning techniques to produce a single crystal flexible film having a desired thickness. The present invention includes preparing an SOI wafer having an buried insulating film and a single crystal layer formed on a base wafer, forming a protective insulating film on the single crystal layer, removing the base wafer to form a flexible film, and removing the insulating film. do.

Monocrystalline Flexible Film, SOI Wafer, Wafer Thinning, Etching

Description

Flexible single crystal film and its manufacturing method {FLEXIBLE FILM WITH SINGLE CRYSTAL AND METHOD OF MANUFACTURING THE SAME}

1 is a manufacturing flowchart of the flexible film produced by Example 1.

2A and 2B are manufacturing process diagrams of the flexible film produced by Example 1;

Figure 3 is a flexible film produced by the present invention.

Figure 4 is a conceptual diagram of measuring the flexibility of the flexible film produced by the present invention.

5 is a manufacturing flowchart of the flexible film prepared by Example 2. FIG.

6A and 6B are manufacturing process diagrams of the flexible film produced by Example 2;

7 is a jig structure diagram of the present invention.

8 is a manufacturing process diagram of the flexible film by the front etching of Example 3.

9A and 9B are manufacturing process diagrams of the flexible film by partial etching of Example 3. FIG.

10 is a manufacturing process chart of the flexible film prepared in Example 4. FIG.

11 is a flexible film prepared by Example 4. FIG.

<Description of Symbols for Major Parts of Drawings>

100, 600, 800, 1000: base wafer

101, 300, 604: nitride film

102, 301, and 603: oxide film

200: bonded wafer

201: ion implantation unit

202, 602, 802, 1002: single crystal layer

601, 801, 1001: insulating film

605: Wax

606: auxiliary support wafer

700: lower plate

701: upper plate

702: Chemical Container

703: fixing means

704: heater

705: Thermometer

900: KOH solution

901: HF Solution

1003: element formation layer

1004: device

1005: element protection film

The present invention relates to a single crystal flexible film for producing a material having flexibility from a semiconductor single crystal wafer and a method of manufacturing the same. That is, the present invention thins an SOI wafer composed of a base wafer, an insulating film, and a single crystal layer by various wafer thinning techniques to produce a single crystal flexible film having a desired thickness.

Moreover, this invention relates to manufacturing the flexible film in which the various electronic element was formed from the semiconductor single crystal wafer. That is, the present invention forms a device having a desired characteristic on an SOI wafer composed of a base wafer, an insulating film, and a single crystal layer, and then thins the wafer by various wafer thinning techniques to form a single crystal flexible film having a desired thickness. Manufacture.

Currently, various electronic devices are being developed as devices having flexibility beyond light weight and miniaturization. In particular, with the display field as an example, with the growth of wireless Internet / e-commerce, the demand for a new concept of flexible display is increasing. Specific types of products are expected to include flexible mobile phones, PDAs, and flexible electronic books and electronic newspapers. Industrial displays and networked stores that work for a long time, such as education / business and CAD / CAM screens such as electronic blackboards, are expected. Signboards, advertising billboards, etc. The scope of use is huge.

However, despite the need for electronic devices with such flexibility, one of the biggest reasons for the delay in development is the absence of a substrate material in which electronic devices of desired characteristics can be stably manufactured. For example, when manufacturing a flexible LCD display, a flexible substrate capable of stably manufacturing a thin film transistor (TFT) array is required. In the prior art, amorphous silicon or polysilicon is formed on a flexible plastic transparent substrate at a low temperature to fabricate a TFT array using a low temperature process, or a polysilicon TFT array is manufactured on a glass substrate and flexible. Or a method of manufacturing an organic TFT using a soft organic semiconductor or transferring to a plastic substrate.

However, when the device is manufactured by using a plastic substrate or the device is manufactured on a glass substrate, then the plastic substrate is used, and thus, the plastic substrate may be deformed due to a difference in thermal expansion coefficient between the organic substrate and the inorganic substrate. In the case of using an organic semiconductor, there is a problem in that desired device characteristics cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to produce a single crystal flexible film that can solve the conventional problems as described above and to ensure flexibility while easily manufacturing an element having desired characteristics. In particular, it is an object of the present invention to easily produce a single crystal flexible film using a single crystal wafer.

Another object of the present invention is to stably manufacture a flexible film having various electronic devices formed on a desired single crystal layer in a simple manner, and to implement desired device properties.

In addition, another object of the present invention is to simplify the manufacturing process for producing a single crystal flexible film to improve productivity and reduce manufacturing cost.

The flexible film according to the present invention is a single crystal flexible film made from a single crystal wafer, and is a flexible film including a flexible insulating layer below or above and below a flexible single crystal layer made from a single crystal wafer.

The single crystal flexible film according to the present invention is a silicon on insulator (SOI) wafer in which an insulating layer and a single crystal layer are formed on a base wafer, and is manufactured as a pure defect free single crystal film by removing the base wafer by using various thinning techniques. The single crystal film according to the invention can control the thickness of the single crystal layer as desired when manufacturing the SOI wafer by the SOI process. For example, it can be freely adjusted in the range of several tens of nanometers to several tens of micrometers. The single crystal layer of the present invention is a silicon single crystal or a single crystal of a compound semiconductor such as gallium arsenide.

The flexible film according to the present invention is a flexible film having various electronic devices manufactured by forming various electronic devices on the single crystal layer of the flexible film, that is, a flexible single crystal layer manufactured from a single crystal wafer and a single crystal layer. It is a flexible film including an element formation layer formed on one surface.

The single crystal flexible film in which the device according to the present invention is formed can be easily manufactured by using a general semiconductor manufacturing process on the SOI single crystal layer in the SOI wafer state, and the base wafer after the device manufacturing process on the single crystal layer is completed. It is a flexible film prepared by removing.

The method for manufacturing a flexible film according to the present invention comprises the steps of preparing an SOI wafer having an insulating film and a single crystal layer formed on the base wafer, forming a protective insulating film on the single crystal layer, removing the base wafer to give flexibility and an insulating film And removing the base wafer to impart flexibility by removing the base wafer. The entire base wafer may be removed by a wet etching method from the KOH solution, and the base remaining after grinding the base wafer to a predetermined thickness. The wafer can be removed from the KOH solution by wet etching. In addition, the forming of the protective insulating film on the single crystal layer is a step of forming an oxide film after forming a nitride film, the step of removing the insulating film is removed by the method of wet etching the insulating film in HF solution.

In addition, the method for manufacturing a flexible film according to the present invention uses a jig, preparing an SOI wafer having an insulating film and a single crystal layer formed on an upper surface of the base wafer, and fixing the SOI wafer with a jig to expose the lower surface of the base wafer. And removing the base wafer to form a flexible film, and when fixing the SOI wafer with a jig, the base wafer is etched by holding the edge of the SOI wafer with the jig to expose the entire lower surface of the base wafer. Alternatively, the base wafer may be etched by holding a peripheral portion of the SOI wafer with a jig to expose a portion of the lower surface of the base wafer. Etching the bottom surface of the base wafer is wet etching the base wafer with a KOH solution, and wet etching the insulating film with a HF solution.

In addition, a method of manufacturing a flexible film having a device according to the present invention includes preparing an SOI wafer having an insulating film and a single crystal layer formed on a base wafer, forming an element forming layer by forming electronic devices on the single crystal layer, and forming a device on the device forming layer. Forming a protective film and removing the base wafer to form a flexible film, the base wafer can be removed by the above various methods.

In addition, in the present invention, a commercially available SOI wafer may be used as it is, and the SOI wafer may be manufactured and used by various other methods. The manufacturing of the SOI wafer includes preparing a base wafer and a bonded wafer, forming an insulating film on the base wafer, implanting hydrogen ions into the bonded wafer, bonding the base wafer and the bonded wafer, and cleaving the bonded wafer. And etching the cleaved surface so that a single crystal layer is formed on the insulating film on the base wafer, and adjusting the depth of cleaving in the cleaving the bonded wafer and etching the remaining cleaved surface. By controlling the thickness of the single crystal layer can be adjusted as desired. For a method of manufacturing such a bonded SOI wafer, reference may be made to Patent Application No. 2002-47351, which is an applicant patent of the present invention.

The preparation of the flexible film according to the invention looks at the silicon single crystal, for example.

Example 1

The production of a single crystal flexible film according to the present invention will be described in more detail below with reference to FIGS. 1 and 2A and 2B.

The silicon bare wafer is prepared as the base wafer 100 and the bonded wafer 200. As shown in a of FIG. 2A, insulating films 101 and 102 are formed on one side of the base wafer to have a constant thickness. At this time, the insulating film is formed of a silicon nitride film (Si ₃ N ₄ , 101) and a silicon oxide film 102 is formed on it. The silicon oxide film may be manufactured by chemical vapor deposition. In addition, the base wafer 100 may use a low resistance wafer doped with a high concentration of impurities in order to increase the etching rate in a subsequent process. As shown in b of FIG. 2A, the bonded wafer 200 implants impurity ions to a predetermined depth from the surface to form an impurity ion implantation unit 201. At this time, hydrogen ions are implanted with a low voltage ion implantation method, and the projection specific distance Rp of the implanted hydrogen ions is formed to be close to the surface of the bonding wafer, for example, within a range of 100 to 500 nm.

The base wafer 100 having the insulating film prepared as described above and the bonded wafer 200 into which the hydrogen ions are injected are cleaned and bonded as shown in c of FIG. 2A. In this case, hydrophilic cleaning is performed to improve bonding strength, and vertical bonding is performed as shown in c of FIG. 2A as soon as possible after the cleaning. In the vertical bonding, the base wafer 100 and the bonded wafer 200 face each other, and are gradually bonded from one end of the wafer. By bonding as described above, two wafers are manufactured to be stacked up and down as shown in FIG.

The two wafers bonded as described above are heat-treated at low temperature to cleave the impurity ion implantation portion of the bonded wafer as shown in FIG. 2A, and the cleaved surface is treated by etching or chemical mechanical polishing (CMP). The silicon single crystal layer 202 is fabricated by the thickness thereof (f in Fig. 2B). In this case, the silicon single crystal layer may be appropriately adjusted in thickness in consideration of an application field.

As described above, the protective insulating layers 300 and 301 are formed on the single crystal layer 202 manufactured on the base wafer 100 as shown in FIG. 2B. The protective insulating film is a film for protecting the silicon single crystal layer from the etching solution when the base wafer is removed by the etching method. First, an oxide film 300 is formed and a nitride film 301 is formed thereon.

When the protective insulating layers 300 and 301 are formed on the silicon single crystal layer as described above, the base wafer is removed by wet etching by dipping them in the KOH solution. In this case, when the base wafer doped with a high concentration of impurities is used, the etching speed is high, so that the base wafer can be removed quickly. In addition, the etching conditions may be controlled by adjusting the etching temperature and the concentration of the etching solution.

When the base wafer is removed as described above, the insulating film remains on the upper and lower portions of the silicon single crystal layer as shown in h of FIG. 2B. In this state, the thickness of the single crystal layer and the insulating film is sufficiently thin, thereby securing some flexibility. When the film is wet etched in HF solution and the upper and lower insulating films are completely removed in the order of the nitride film and the oxide film, only the silicon single crystal layer remains, thereby forming a pure single crystal flexible film as shown in FIG. 2B. In addition, if only the insulating film on one surface of the upper or lower portion is removed by etching, it can be made of a flexible film composed of the insulating film and the silicon single crystal layer.

Since the flexible film manufactured as described above can be adjusted from several tens of micrometers to several tens of nanometers, the pure silicon single crystal film 202 having excellent flexibility of FIG. 3A and the insulating film 102 of FIG. The flexible film 203 made of the silicon single crystal layer 202 may be used for various applications. The insulating film 102 of the flexible film made of the insulating film and the silicon single crystal layer may be used to handle the silicon single crystal layer during handling. Will be protected.

In particular, to determine the degree of flexibility of the prepared silicon single crystal film, the radius of curvature to the point of material destruction was calculated. That is, if the silicon wafer having a thickness d is bent to the radius of curvature R as shown in Fig. 4A, the stress applied at this time can be expressed by the following equation.

σ = (d / 2R) E (<σ _y and <σ _f )

Where σ is stress, d is thickness, R is radius of curvature, E is elastic modulus, σ _y is yield stress and sigma _f is fracture stress.

Normally E is 190 GPa, sigma _y is 6.9 GPa, and sigma _f is 2.8 GPa. Therefore, the radius of curvature at the point when the silicon wafer having a thickness of 0.725 mm is maximally bent and broken is calculated to be about 5 meters. (A) of FIG. 4, the thickness of the silicon single crystal flexible film prepared in the present invention is 1 The radius of curvature achievable when thinning to [mu] m was calculated to be 6 mm (Fig. 4b). Therefore, it can be seen that the silicon single crystal flexible film prepared in the present invention has sufficient flexibility as desired.

Example 2

The production of a single crystal flexible film by grinding according to the present invention will be described in more detail below with reference to FIGS. 5 and 6A and 6B.

As shown in Fig. 6A, an SOI wafer formed of a base wafer 600, an insulating film 601 formed thereon, and a silicon single crystal layer 602 formed on the insulating film is prepared. Such SOI wafers may be made of a separation by implanted oxygen (SIMOX) wafer or a SOI wafer by bonding, or may be a commercially available wafer. At this time, the thickness of the insulating film is used as thick as possible, the thickness of the single crystal layer is adjusted according to the application field.

Protective insulating films 603 and 604 are formed on the SOI wafer prepared as described above. This protective insulating film is a film for protecting a silicon single crystal layer when the base wafer is removed, and an oxide film 603 is first formed and a nitride film 604 is formed thereon (c in Fig. 6A).

After the wax 605 is coated with the adhesive on the insulating film formed as described above (d in FIG. 6A), the auxiliary support wafer 606 is attached thereon (e in FIG. 6A). At this time, the wax may select water solubility that is well soluble in water, and the attachment of the auxiliary support wafer is performed by vertical or horizontal bonding. Auxiliary support wafer 606 is for protecting and facilitating the SOI wafer in subsequent grinding processes. In other words, when grinding an SOI wafer, the thickness of the wafer is ground as the wafer is ground, resulting in a problem of breaking the wafer in the grinding chuck. The wafer can be safely held in the chuck without being broken.

With the auxiliary support wafer attached as described above, the base wafer is ground to a predetermined thickness as shown in f of FIG. 6B. At this time, the grinding thickness can be freely adjusted.

After grinding as above, the auxiliary support wafer 606 is separated by melting the wax using an aqueous solution or a chemical (g of FIG. 6B).

After removing the auxiliary support wafer 606 as described above, it is wet etched in a KOH solution to remove the residue 600a of the ground and remaining ground wafer (FIG. 5H).

When the base wafer is removed as described above, the insulating films 604, 603, and 601 remain on the upper and lower portions of the silicon single crystal layer 602 as shown in FIG. 5H. In this state, the thickness of the single crystal layer and the insulating film becomes sufficiently thin. The castle is secured to some extent. When the film is wet etched in HF solution and the upper and lower insulating films are completely removed in the order of the nitride film and the oxide film, only the silicon single crystal layer remains as shown in FIG. 6B, thereby forming a pure single crystal flexible film. In addition, if only the insulating film on one surface of the upper or lower portion is removed by etching, a flexible film including the insulating film and the silicon single crystal layer may be manufactured.

When the flexible film is produced by this method, the etching time in the KOH solution can be significantly shortened, and the etching flatness is good because it is mechanically polished to a predetermined thickness. In addition, a single crystal flexible film can be easily produced from a commercially available SOI wafer by the thinning method of this embodiment.

Example 3

The manufacturing of the single crystal flexible film using the jig according to the present invention will be described in more detail below with reference to FIGS. 7 and 9A and 9B.

First, the jig used in the present invention will be described. As shown in FIG. 7, the jig includes an upper plate 701 and a lower plate 700, and a wafer 706 is installed between the upper plate and the lower plate. Each such plate is made of a chemically stable material such as Teflon. The upper plate is provided with a chemical bath 702 at the upper portion where the upper plate and the lower plate are combined to contain a chemical solution. These chemical containers are manufactured in a penetrating type, and are manufactured in various forms as necessary, such as a rectangular cylinder and a cylinder. In addition, the upper plate and the lower plate is provided with fixing means 703 for fixing the two plates when the two plates are bonded.

Using such a jig, only one side of the wafer may be wet-side etched. That is, the surface of the wafer 706 to be etched is installed on the lower plate 700 so as to face the upper plate 701, the upper plate and the lower plate are bonded and fixed, and then the etching solution is supplied to the chemical container 702 to expose them. One side of the prepared wafer is etched. At this time, the heater 704 and the thermometer 705 coated with Teflon are installed in the chemical container according to the etching conditions and the etching temperature is controlled.

A process of etching one entire surface of the base wafer using a jig will be described in more detail below with reference to FIG. 8.

An SOI wafer formed of a base wafer 800, an insulating film 801 formed thereon, and a silicon single crystal layer 802 formed over the insulating film is prepared with the surface to be etched up as shown in FIG. Using the jig described above, the prepared wafer is held by holding a wafer edge so as to expose the entire back side of the base wafer (the surface without single crystal) (Fig. 8B).

As described above, the base wafer is etched by supplying the KOH solution 900 to the rear surface of the fixed and exposed base wafer (FIG. 8c), and after discharging the KOH solution, the HF solution 901 is supplied to the insulating film 801. ) Is etched (FIG. 8 d) to produce a pure silicon single crystal flexible film (FIG. 8 e). At this time, removal of the insulating film by the HF solution may be performed while the jig is fixed, or the jig may be removed and the entire object to be treated may be dipped in the HF solution.

In addition, if only the KOH etching is performed in the above step and the jig is released, the flexible film may be made of an insulating film and a silicon single crystal layer.

A process of etching a portion of one side of the base wafer using a jig will be described in more detail below with reference to FIGS. 9A and 9B.

As shown in Fig. 9A, an SOI wafer formed of a base wafer 800, an insulating film 801 formed thereon, and a silicon single crystal layer 802 formed over the insulating film is prepared. Using the jig described above, the prepared wafer is pressed to fix the wafer peripheral portion to the upper plate so that a part of the back side of the base wafer is exposed (b of FIG. 9A).

As described above, the base wafer is etched by supplying a KOH solution to the rear surface of the fixed and exposed base wafer (FIG. 9A), and after discharging the KOH solution, the HF solution is supplied to etch the insulating film. d-1) That is, the base wafer is etched by the KOH solution and the insulating film serves as an etch stop layer. Thereafter, after discharging the KOH solution, when HF solution is supplied, the insulating film is etched by HF. At this time, the insulating film by the HF solution may be removed while the jig is fixed (d-1 in Fig. 9A), or the jig may be removed and the whole object to be treated may be dipped in the HF solution (d-2 in Fig. 9B).

By cutting the peripheral portion of the object to be etched as described above to produce a pure silicon single crystal flexible film (e) of FIG.

In addition, if only the KOH etching is performed in the above step and the peripheral portion of the object is cut, the flexible film may be made of an insulating film and a silicon single crystal layer.

The method for etching only one side of the wafer using the jig can easily produce a single crystal flexible film through a simple process. That is, since the back surface of the base wafer is etched using a jig without any additional process, the process step is reduced. In addition, it is possible to easily remove the unneeded wafer periphery and to change the shape of the chemical container of the top plate to produce a flexible film of the desired shape. That is, a circular wafer is caught and etched using a jig having a rectangular cylindrical chemical container, and the peripheral portion is cut to obtain a rectangular single crystal flexible film.

Example 4

The manufacturing of the single crystal flexible film having the device according to the present invention will be described in more detail below with reference to FIGS. 10 and 11.

As shown in FIG. 10A, an SOI wafer 1006 formed of a base wafer 1000, an insulating film 1001 formed thereon, and a silicon single crystal layer 1002 formed on the insulating film is prepared.

Various electronic devices are formed on a single crystal layer of the SOI wafer prepared as described above using a general semiconductor manufacturing process (Fig. 10B). The electronic device 1004 may be manufactured in various ways according to the desired purpose. That is, it can be designed according to desired characteristics such as various transistors, TFT arrays, logic circuits, etc., and can be manufactured using semiconductor manufacturing processes.

A protective film 1005 (Fig. 10C) for protecting the device is formed on the device formation layer in which the various devices are formed as described above. As the passivation film, a general passivation film, an organic insulating film, or the like can be used.

As described above, the base wafer 1000 is removed from the manufactured SOI wafer of the device layer to prepare a flexible film (FIG. 10D). At this time, the manufacturing of the base wafer can be removed in the same manner as in Example 1 to Example 3.

The flexible film produced as described above is in a flexible film state with sufficient flexibility in which a desired element is formed on single crystal silicon as shown in FIG. FIG. 11A is a flexible film in which the element is formed on the flexible pure silicon single crystal layer, and FIG. 11B is a form in which the element is formed on the flexible film composed of the insulating film and the silicon single crystal layer. And to protect the device.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to this, A deformation | transformation and improvement are possible by a person with ordinary skill in the art within the technical idea of this invention.

The single crystal flexible film of this invention by the structure mentioned above has the effect which can ensure flexibility while being able to manufacture the element of a desired characteristic easily. In particular, a single crystal flexible film can be easily produced using a single crystal wafer.

In addition, the present invention can stably manufacture a flexible film having various electronic devices formed on a desired single crystal layer by a simple method, and implement desired device characteristics. That is, since various devices are manufactured on the single crystal layer, an active layer for the device is formed from the single crystal layer, and the semiconductor process is applied, and thus the electron mobility value is excellently high at 1000 cm ² / Vsec, thereby obtaining excellent device characteristics. Leakage current can also be significantly reduced compared to other flexible materials. In addition, it is possible to reduce the size of various electronic devices to the size of a general semiconductor device, and by applying a semiconductor process through a silicon wafer, a semiconductor photo and etching process that has a stable high-temperature process and excellent alignment accuracy is present. Circuit design is possible with fine design rules down to 30 nm possible in the process.

In addition, since the present invention can use a single crystal stable channel device, it is possible to integrate a semiconductor circuit for a specific use including a system on panel (SOP) and other memory, a system IC, a processor, etc., in which all driving circuits are integrated. It is possible to realize the elements in a flexible film.

In addition, the present invention can manufacture a single crystal flexible film using a suitable thinning technology according to the situation, it is possible to simplify the manufacturing process for producing a single crystal flexible film to improve productivity and reduce the manufacturing cost.

Claims (34)

A single crystal layer made from a silicon single crystal wafer, An element formation layer formed on the single crystal layer, The single crystal layer is a flexible film, characterized in that it comprises a silicon single crystal flexible wafer having a thickness of several tens of nanometers to several hundred nanometers. The flexible film of claim 1, wherein the flexible film further comprises a flexible insulating layer on one surface. delete delete delete delete delete The flexible film of claim 1 or 2, further comprising a protective layer on the device formation layer. Preparing an SOI wafer having an insulating film and a single crystal layer formed on a heavily doped base wafer, Forming a protective insulating film on the single crystal layer; Removing the base wafer by wet etching to provide flexibility; Removing the insulating film Flexible film production method comprising the. The method of claim 9, wherein preparing the SOI wafer comprises: Preparing a base wafer and a bonded wafer; Forming an insulating film on the base wafer; Implanting hydrogen ions into the bonded wafer; Bonding the base wafer and the bonded wafer; Cleaving the bonded wafer; And etching the cleaved surface to produce an SOI wafer having a single crystal layer formed over the insulating film of the base wafer. The method of claim 10, wherein forming an insulating film on the base wafer Forming a nitride film on the base wafer; A method of manufacturing a flexible film, further comprising the step of forming an oxide film on the nitride film. 12. The method of claim 10 or 11, further comprising cleaning prior to bonding the base wafer and the bonded wafer. delete 12. The method of any one of claims 9 to 11, wherein forming the protective insulating film on the single crystal layer comprises: forming an oxide film; A method of manufacturing a flexible film, further comprising the step of forming a nitride film on the oxide film. The method of claim 9, wherein the removing of the insulating layer comprises removing all of the insulating layer by HF wet etching. The method of claim 9, wherein removing the insulating film comprises removing an insulating film on one surface of the single crystal layer by an HF wet etching method. . 15. The method of claim 14, wherein removing the base wafer to form the flexible film comprises removing the base wafer by wet etching with KOH. 18. The method of claim 17, wherein removing the insulating film comprises removing all of the insulating film by HF wet etching. Preparing an SOI wafer having an insulating film and a single crystal layer formed on the base wafer; Forming a protective insulating film on the single crystal layer; Coating wax on the protective insulating layer; Combining the SOI wafer and the auxiliary support wafer; Grinding the base wafer to a predetermined thickness or less; Separating and removing the auxiliary support wafer; And removing the residue of the remaining base wafer after the grinding by wet etching to give flexibility. 20. The method of claim 19, comprising removing all of the insulating film by an HF wet etching method. 20. The method of claim 19, comprising removing an insulating film on one surface of the single crystal layer by an HF wet etching method. Preparing an SOI wafer having an insulating film and a single crystal layer formed on an upper surface of the base wafer, Fixing the SOI wafer with a jig to expose the bottom surface of the base wafer; Removing the base wafer by wet etching to provide flexibility. Flexible film production method comprising the. 23. The method of claim 22, wherein securing the SOI wafer comprises jig- ing the edges of the SOI wafer to expose the entire bottom surface of the base wafer. 23. The method of claim 22, wherein fixing the SOI wafer comprises jig-tagging the periphery of the SOI wafer to expose a portion of the bottom surface of the base wafer. 25. The method of claim 24, wherein removing the base wafer to impart flexibility further comprises cutting the periphery of the jig. 26. The method of any one of claims 22 to 25, wherein removing the base wafer to impart flexibility comprises wet etching with KOH. 26. The method of any one of claims 22-25, wherein removing the base wafer to impart flexibility comprises: wet etching with KOH, A method of manufacturing a flexible film comprising wet etching with HF. 28. The method of claim 27, wherein the wet etching with HF comprises unzipping and dipping into an etchant to etch. delete Preparing an SOI wafer having an insulating film and a single crystal layer formed on a heavily doped base wafer, Forming an element formation layer by forming electronic elements on the single crystal layer; Forming a device protection film on the device formation layer; Removing the base wafer by wet etching to give flexibility. Preparing an SOI wafer having an insulating film and a single crystal layer formed on the base wafer; Forming an element formation layer by forming electronic elements on the single crystal layer; Forming a device protection film on the device formation layer; Grinding the base wafer to a predetermined thickness or less; And removing the residue of the remaining base wafer after the grind by wet etching to give flexibility. Preparing an SOI wafer having an insulating film and a single crystal layer formed on the base wafer; Forming an element formation layer by forming electronic elements on the single crystal layer; Forming a device protection film on the device formation layer; Fixing the SOI wafer with a jig to expose the bottom surface of the base wafer; Removing the base wafer by wet etching to impart flexibility. 33. The method of any one of claims 30 to 32, wherein removing the base wafer to produce a flexible film further comprises wet etching the base wafer with KOH and then etching it with HF. Flexible film manufacturing method. 33. The method of any one of claims 30 to 32, wherein forming the device formation layer by forming an electronic device on the single crystal layer comprises using a semiconductor manufacturing process.

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