JP2008240025A - Apparatus and method for thin film formation, method for enabling polarization reversal, method for measuring ferroelectric property, thin film and capacitor structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus 1 for thin film formation, capable of efficiently forming a thin film 51 in a short period of time. <P>SOLUTION: An evaporation source 30 in which a VDF oligomer 33 is disposed and a substrate 10 to be subjected to vapor deposition are separated from each other while the evaporation source 30 is heated. Then, a separated state in which the substrate 10 and the evaporation source 30 are separated from each other is shifted into a neighboring state in which a thin film formation surface 11 of the substrate 10 and a VDF oligomer supplying surface 32 of the evaporation source 30 come close to and face each other across a heat-insulating mask 20 by moving the substrate 10 and/or the evaporation source 30. In the neighboring state, the thin film 51 of the VDF oligomer 33 is deposited onto the thin film formation surface 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes, for example, a thin film forming apparatus and a thin film forming method for forming a vinylidene fluoride oligomer thin film on a deposition substrate, a polarization reversal enabling method for enabling polarization reversal of the thin film formed by these, and the thin film The present invention relates to a ferroelectric characteristic measuring method for measuring the ferroelectric characteristic of the thin film, a thin film manufactured by these methods, and a capacitor structure.

Conventionally, a vacuum deposition method is generally known as a method for producing a functional organic thin film using a low molecular material. In this vacuum deposition method, a material placed in a “crucible” is heated under a high vacuum of about 10 ⁻⁵ Pa, sublimated, and physically adsorbed on the substrate surface.

  This vacuum deposition method is a clean film formation method that can prevent impurities from entering the film. However, this vacuum deposition method has a disadvantage in terms of manufacturing in that a device for making a high vacuum is large and expensive, and it takes a long time from reaching a high vacuum to completion of film formation.

On the other hand, a thin film forming method has been proposed in which a thin film is formed by depositing a film material on a thin film forming surface of a deposition target substrate (see Patent Document 1).
In this thin film forming method, the thin film forming surface of the deposition substrate and the material supply surface of the supply substrate carrying the film material on the material supply surface are arranged in close proximity to each other with a predetermined gap secured, and the material supply surface By evaporating the film material above, a thin film of the film material is formed on the thin film forming surface.

  According to this thin film forming method, it is possible to form a good thin film on the thin film forming surface of the evaporation target substrate without increasing the distance between the evaporation target substrate and the supply substrate, and to deposit in a low vacuum atmosphere. ing.

  However, in this thin film formation method, in order to obtain a uniformly oriented and crystallized film quality, the deposition rate is 0.5 nm / min or less (see paragraph [0064]), and a thin film having a necessary thickness is obtained. However, there remains a problem that a certain amount of time is required.

  As a method for producing a vinylidene fluoride oligomer thin film, a method for producing a vinylidene fluoride oligomer thin film has been proposed (see Patent Document 2). In this method for producing a vinylidene fluoride oligomer thin film, a thin film is formed by depositing or spraying a vinylidene fluoride oligomer while cooling the substrate to −130 ° C. or lower.

The reason why the substrate is cooled in Patent Document 2 is to align the vinylidene fluoride oligomer in parallel with the substrate.
More specifically, the vinylidene fluoride oligomer has H and F atoms in a carbon straight chain, and has a permanent dipole moment due to the difference in electronegativity between H + and F−. In order for this material to exhibit ferroelectricity, when considering a ferroelectric capacitor structure sandwiched between electrodes, it is necessary that carbon straight chains be oriented parallel to the electrodes.

  In Patent Document 2, if the substrate temperature is set to about room temperature, when molecules are adsorbed to the substrate, the molecules diffuse in a standing manner and meet other adsorbed molecules to start forming crystals. At this time, since the molecules are standing, the crystals are oriented perpendicular to the substrate and are not parallel oriented.

  For this reason, in the said patent document 2, the board | substrate is made into low temperature. Thereby, the molecules adsorbed on the substrate do not diffuse because the thermal energy received from the substrate is small, and fall down on the spot and are parallel-aligned. Since crystallization proceeds in this state, a ferroelectric crystal can be formed by the method of Patent Document 2.

  However, the method of Patent Document 2 requires a device for cooling, and has a problem that the cost of the device becomes expensive together with a device for obtaining a high vacuum.

JP 2006-152352 A JP 2004-76108 A

  In view of the above-mentioned problems, the present invention provides a thin film forming apparatus, a thin film forming method, a polarization inversion enabling method, a ferroelectric property measuring method, a thin film, and a capacitor structure that can form a thin film efficiently in a short time. Objective.

  The present invention is a thin film forming apparatus for forming a thin film of vinylidene fluoride oligomer by vapor-depositing a vinylidene fluoride oligomer on a thin film forming surface of a deposition target substrate, and a deposition target substrate holding unit that holds the deposition target substrate; A vapor deposition source holding unit that holds a vapor deposition source in which a vinylidene fluoride oligomer is disposed, a heating unit that heats the vapor deposition source, and a vapor deposition substrate disposed between the vapor deposition substrate and the vapor deposition source, from the vapor deposition substrate side. A heat-insulating member provided with a through-hole penetrating to the vapor deposition source side, and a separated state in which at least one of the vapor deposition substrate holding part and the vapor deposition source holding part is moved to separate the vapor deposition substrate and the vapor deposition source. And a moving means for changing the thin film forming surface of the substrate to be deposited and the vinylidene fluoride oligomer supply surface of the deposition source to face each other and close to each other with the heat insulating member interposed therebetween. Characterized in that it is a forming apparatus.

  As an aspect of the present invention, the moving unit can be configured to change from the separated state to the close state when the vapor deposition source reaches a predetermined temperature due to heating of the heating unit.

  As an aspect of the present invention, the vapor deposition substrate holding portion can be configured to fix the vapor deposition substrate and the heat insulating member.

  Further, as an aspect of the present invention, there is provided an open / close shutter that partitions the heat insulating member and the vapor deposition source in the separated state and opens the space between the heat insulating member and the vapor deposition source when changing to the close state. Can be provided.

As an aspect of the present invention, the deposition target substrate holding unit, the heat insulating member, and the deposition source holding unit can be disposed in a reduced pressure atmosphere.
Moreover, as an aspect of this invention, it can be set as the structure which patterns the thin film formed in the thin film formation surface of the said to-be-deposited substrate by arrangement | positioning and shape of the through-hole of the said heat insulation member.

  According to another aspect of the present invention, a mask member for patterning a thin film formed on a thin film forming surface of the deposition substrate is formed by forming a through hole of the heat insulating member larger than a thin film formation region of the deposition substrate. It can be set as the structure piled up on the thin film formation surface.

  Further, as an aspect of the present invention, the deposition target substrate holding unit can be provided with a displacement allowing portion that allows the deposition target substrate and the heat insulating member to be angularly displaced following the deposition source when in the proximity state.

  The present invention also provides a thin film forming method for forming a vinylidene fluoride oligomer thin film by depositing a vinylidene fluoride oligomer on a thin film forming surface of a substrate to be vapor-deposited, wherein the vinylidene fluoride oligomer is disposed; At least one of the deposition target substrate and the deposition source is moved from a heating step of heating the deposition source in a state where the deposition target substrate is separated from and a separated state in which the deposition target substrate and the deposition source are separated from each other. A moving step in which the thin film forming surface of the substrate to be deposited and the vinylidene fluoride oligomer supply surface of the deposition source are opposed to and in close proximity with a heat insulating member interposed therebetween, and the vinylidene fluoride oligomer in the proximity state A thin film forming method including a vapor deposition step of depositing the thin film on the thin film forming surface.

  As an aspect of the present invention, a shutter opening step of moving a shutter partitioning between the heat insulating member and the vapor deposition source to an open state immediately before or during the moving step can be provided.

As an aspect of the present invention, the vapor deposition step can be performed in a reduced pressure atmosphere.
Further, as an aspect of the present invention, each of the steps can be performed using the deposition target substrate at about room temperature.

Further, as an aspect of the present invention, a material obtained by patterning the vinylidene fluoride oligomer is used as the deposition source.
As an aspect of the present invention, the vinylidene fluoride oligomer that has been thinned by the vapor deposition step can have components that are aligned in parallel to the vapor deposition substrate.

  In addition, the present invention can be a polarization inversion enabling method that enables polarization inversion by repeatedly applying a rectangular wave having an electric field higher than the coercive electric field to the vinylidene fluoride oligomer thin film formed by the thin film formation method.

  In addition, the present invention provides a polarization inversion enabling method for applying polarization to the thin film of vinylidene fluoride oligomer formed by the thin film forming method by applying an electric field while heating the deposition target substrate and raising the temperature. be able to.

  The present invention also provides a measurement for measuring the ferroelectric characteristics of the thin film after performing an electric field intermittent application step of repeatedly applying a rectangular wave having an electric field higher than the coercive electric field to the vinylidene fluoride oligomer thin film formed by the thin film forming method. It can be set as the ferroelectric characteristic measuring method which performs a process.

In addition, the present invention can be a vinylidene fluoride oligomer thin film that produces four peaks when the IV characteristics are measured and a propeller-type hysteresis when the QV characteristics are measured.
In addition, the present invention can provide a capacitor structure in which a thin film of the vinylidene fluoride oligomer is interposed between two electrodes.

  According to the present invention, it is possible to provide a thin film forming apparatus, a thin film forming method, a polarization inversion enabling method, a ferroelectric property measuring method, a thin film, and a capacitor structure that can efficiently form a thin film in a short time.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a partial front sectional view showing the configuration of the thin film forming apparatus 1 of the first embodiment, and FIG. 2 is a plan view of the heat insulating mask 20.

  The thin film forming apparatus 1 includes a holder 3 that moves up and down, a shutter 27 that opens and closes left and right, and a stage in a chamber 2 that is decompressed by a rotary pump (not shown) to create a low vacuum atmosphere of 0.3 to 1 Pa inside. 40 and the ceramic heater 45 are arranged mainly in this order from the top. The temperature in the chamber 2 is not particularly adjusted, and is about room temperature.

  The holder 3 includes a plate portion 5 having a substantially square shape in plan view and a fixed claw 4 provided on the lower surface of the edge portion of the plate portion 5. The holder 3 has a flexible coupling 6 attached to the center of the upper surface of the plate portion 5. The flexible coupling 6 is provided with a cylindrical arm 7 extending vertically.

  The holder 3 attaches the vapor deposition substrate 10 disposed so as to overlap the horizontal lower surface of the plate portion 5 and the heat insulating mask 20 disposed in close contact with the lower surface of the vapor deposition substrate 10 to the fixing claw 4. Secure with. As a result, when the holder 3 moves up and down by an elevating drive unit (not shown), the deposition target substrate 10 and the heat insulating mask 20 move up and down together with the holder 3 while being in close contact with each other.

  The flexible coupling 6 is a member that bends flexibly and absorbs declination and eccentricity. When the holder 3 is lowered to the lowest position by the flexible coupling 6, the holder 3 is deviated or decentered following the vapor deposition source 30, and the lower surface of the heat insulating mask 20 is in close contact with the upper surface of the vapor deposition source 30.

  The deposition target substrate 10 is formed in a horizontal plate shape having a constant thickness, and in this embodiment, a quartz substrate formed in a square shape in plan view is used. The lower surface of the vapor deposition substrate 10 is a thin film forming surface 11, and an aluminum mask pattern is applied in this embodiment.

  The heat insulating mask 20 is formed with a plurality of through holes 21 penetrating in the thickness direction in a horizontal plate shape having a constant thickness. In this embodiment, as shown in FIG. 2, 36 through-holes 21 having a diameter of 1 mm are formed 6 × 6 in a vertical and horizontal direction at a distance of 2 mm between each hole center. The thickness of the heat insulating mask 20 is 2 mm. Accordingly, the through hole 21 is formed in a cylindrical shape having a diameter of 1 mm and a height of 2 mm. The heat insulating mask 20 is made of a heat insulating material capable of glass processing such as quartz or ceramic. In this embodiment, the heat insulating mask 20 is made of special synthetic quartz. This special synthetic quartz has a thickness of 2 mm and can suppress heat transfer to such an extent that when the heat of 300 ° C. is applied to one side for 1 minute, the deposition target substrate 10 on the opposite side becomes 40 ° C. Note that the shape and arrangement pattern of the through holes 21 of the heat insulating mask 20 are not limited to this, and may be an appropriate shape according to a pattern in which a thin film is to be formed on the deposition target substrate 10. At this time, the arrangement pattern of the through holes 21 on the upper surface of the heat insulating mask 20 may be a mirror pattern of a pattern to be formed into a thin film on the deposition target substrate 10.

  As shown in FIG. 1, a horizontal shutter 27 is provided at a height near the center of the chamber 2. The shutter 27 partitions the interior of the chamber 2 up and down in the illustrated closed state, and completely blocks the upper space 2a and the lower space 2b. Thereby, the radiant heat from the lower space 2b by the ceramic heater 45 or the like is not transmitted to the heat insulating mask 20 and the deposition target substrate 10 in the upper space 2a. When the shutter 27 is slid rightward in FIG. 1 by the opening / closing drive unit (not shown) and opened, the chamber 2 is not partitioned, and the upper space 2a and the lower space 2b communicate with each other.

  In the lower space 2b of the chamber 2, a ceramic heater 45 is disposed near the bottom, a stage 40 is disposed thereon, and a vapor deposition source 30 is disposed thereon.

The vapor deposition source 30 has a VDF (vinylidene fluoride) oligomer [CF ₃ (CH ₂ CF ₂ ) nC ₂ H ₅ ] 33 as a film material on the upper surface of a plate 31 formed in a flat plate shape with a constant thickness. Arranged and configured. Here, “n” in the chemical formula is the number of monomers, and represents the number of repetitions of “CH ₂ CF ₂ ”. In this embodiment, the VDF oligomer 33 whose “n” is “13.4” is used. In addition, although n is an integer originally, the above “13.4” indicates an average molecular weight at the stage of synthesis.

  The upper surface of the plate 31 is a VDF oligomer supply surface 32. For example, the vapor deposition source 30 can be manufactured by dissolving VDF oligomer 13.4-mer powder in acetone at a rate of 1 wt%, and dropping and drying the solution on a heat stage. In this embodiment, the shape of the vapor deposition source 30 is formed in a square shape in plan view according to the shapes of the vapor deposition substrate 10 and the heat insulating mask 20. In this embodiment, the VDF oligomer 33 is arranged in the same arrangement pattern as the arrangement pattern of the through holes 21 of the heat insulating mask 20, that is, the pattern to be formed into a thin film on the deposition target substrate 10. The arrangement of the VDF oligomer 33 is not limited to this, and may be arranged in an appropriate pattern, or may be arranged on the entire upper surface of the plate 31.

  The stage 40 has a uniform plate thickness and a horizontal plate shape, and is formed of a material having high thermal conductivity. In this embodiment, the copper material is formed into a quadrangular shape in plan view in accordance with the shapes of the deposition target substrate 10 and the heat insulating mask 20.

  The ceramic heater 45 is composed of a ceramic heater that can raise the temperature at high speed. In this embodiment, the vapor deposition source 30 is composed of a ceramic heater capable of raising the temperature to 300 degrees Celsius in 3 minutes, and is formed in a square shape in plan view according to the shapes of the vapor deposition substrate 10 and the heat insulating mask 20.

  In the thin film forming apparatus 1 configured in this manner, the vertical drive of the holder 3, the opening / closing drive of the shutter 27, and the heating increase of the ceramic heater 45 are controlled by a control unit (not shown).

  FIG. 3 is a flowchart showing a method of forming a thin film by the thin film forming apparatus 1, FIG. 4 is a partial front sectional view showing the structure of the thin film forming apparatus 1, and FIG. 5 explains how the VDF oligomer 33 is deposited. It is explanatory drawing.

  As shown in FIG. 1, the thin film forming apparatus 1 raises the holder 3 to the uppermost position, closes the shutter 27, and reduces the pressure in the chamber 2 to a low vacuum atmosphere of 0.3 to 1 Pa with a rotary pump. A process is implemented and it transfers to an initial state (step S1). At this time, the deposition target substrate 10 before the VDF oligomer 33 deposition and the heat insulating mask 20 are fixed to the holder 3, and the deposition source 30 before the VDF oligomer 33 evaporation is fixed on the stage 40.

  The thin film forming apparatus 1 performs the heating process to heat the ceramic heater 45 (step S2), and continues the heating until reaching a preset deposition start temperature (in this example, about 120 ° C.) (step S3: NO). ).

  When the deposition start temperature is reached (step S3: YES), the thin film forming apparatus 1 performs a shutter opening process, and slides the shutter 27 horizontally to a fully opened state shown in FIG. 4 (step S4). Then, the thin film forming apparatus 1 performs the proximity process, lowers the holder 3, and makes the lower surface of the heat insulating mask 20 come into surface contact with the upper surface of the vapor deposition source 30 (step S5).

  At this time, as shown in FIG. 5, the upper and lower openings of the through holes 21 formed in the heat insulating mask 20 are opposed to and adjacent to the thin film forming surface 11 of the evaporation target substrate 10 and the VDF oligomer supply surface 32 of the evaporation source 30. It is almost sealed between. Therefore, the through hole 21 is a local closed space having a diameter of 1 mm and a height of 2 mm.

  Then, the VDF oligomer 33 receives the heat of the ceramic heater 45 through the stage 40 and the plate 31 and sublimates to become gas molecules 33a, which is released from the VDF oligomer supply surface 32 and released into the through hole 21. Since the inside of the through hole 21 is a very limited space by being almost sealed, the vapor pressure exceeds the equilibrium vapor pressure, and the degree of supersaturation is high. For this reason, the liquid crystal growth from the gas phase is effectively promoted.

  The thin film forming apparatus 1 waits until a predetermined vapor deposition time (45 seconds in this embodiment) elapses after the holder 3 is lowered, and performs the vapor deposition process (step S6: NO) to advance the vapor deposition. .

  Here, the inside of the through-hole 21 has a steep temperature gradient, the lower vapor deposition source 30 side is at a high temperature (in this embodiment, the vapor deposition source 30 is about 120 ° C. to 180 ° C.), and the upper vapor deposition substrate. The 10 side is at a low temperature (in this embodiment, the deposition target substrate 10 is about 50 ° C. or less).

  In particular, at the moment when the holder 3 is lowered and the through hole 21 is sealed, the substrate to be deposited 10 is at the atmospheric temperature in the chamber 2 (room temperature in this embodiment), and the deposition source 30 is about 120 degrees Celsius. Therefore, at this moment, a very steep temperature gradient is formed between the deposition target substrate 10 and the deposition source 30.

  Further, even when the vapor deposition time (45 seconds in this embodiment) elapses, due to the heat insulation function of the heat insulation mask 20, the vapor deposition substrate 10 is about 50 degrees Celsius and the vapor deposition source 30 is about 180 degrees Celsius. Therefore, a steep temperature gradient between the evaporation target substrate 10 and the evaporation source 30 can be maintained while the evaporation process is performed.

  In order to maintain this rapid temperature gradient, it is also contributed that the temperature of the vapor deposition source 30 is continuously increased so that the temperature at the time of completion of vapor deposition is higher than the time of vapor deposition. In this embodiment, the temperature of the vapor deposition source 30 is increased to the same degree or more than the temperature difference at which the temperature of the vapor deposition substrate 10 increases during the vapor deposition time.

  Thus, the gas molecules 33a separated from the vapor deposition source 30 due to a very rapid temperature gradient are vapor-deposited on the thin film forming surface 11 of the vapor deposition substrate 10 having the lowest temperature, and the orientation of the gas molecules 33a varies. It accumulates efficiently.

  When the deposition time elapses (step S6: YES), the thin film forming apparatus 1 performs the separation process and raises the holder 3 to the uppermost position (step S7). Then, the thin film forming apparatus 1 performs a shutter closing process, and slides the shutter 27 horizontally to make it fully closed (step S8).

  Through the above steps, a thin film having a pattern shape and a mirror pattern of the through holes 21 formed on the upper surface of the heat insulating mask 20 is efficiently formed in a low vacuum atmosphere on the thin film forming surface 11 of the evaporation target substrate 10 in a short time. be able to.

  In this example, the thickness of the thin film formed with the deposition time of 45 seconds was about 400 nm. Therefore, in contrast to the conventional thin film formation rate of 0.5 nm / min, this example realized a very high thin film formation rate of about 533 nm / min.

  Moreover, since the thin film 51 of the VDF oligomer 33 can be formed at room temperature without cooling the deposition target substrate 10 in a low vacuum atmosphere, the thin film forming apparatus 1 can be provided at low cost.

Further, according to the above-described embodiment, the VDF oligomer 33 that is a linear molecule can be aligned on the evaporation target substrate 10 with the linear chain being parallel, and the alignment can be controlled.
More specifically, if the substrate is set to about room temperature by the method of the conventional example shown in Patent Document 2, normally, the vertical alignment is dominant, and it is considered that the VDF oligomer is not parallel aligned.
However, in the above-described embodiment, the degree of supersaturation is sufficiently increased, so that a large number of molecules exist in the vapor deposition atmosphere (in the through hole 21). Then, the molecules of the VDF oligomer that have reached the thin film forming surface 11 of the deposition target substrate 10 meet other molecules before being diffused, and are absorbed and thinned. As a result, the orientation of the molecules becomes random, and the number of parallel orientation components increases stochastically as compared with film formation from a normal crucible. In this way, alignment control can be performed so as to achieve parallel alignment.

  FIG. 6 is a plan view of a capacitor 50 manufactured using the evaporation target substrate 10 having a thin film formed according to the above-described embodiment. The plan view of the capacitor 50 corresponds to the bottom view of the deposition target substrate 10 shown in FIG.

  A plurality of straight lower electrodes 13 are formed in advance on the deposition substrate 10 using aluminum pattern wiring, and a VDF oligomer thin film 51 is formed thereon by the thin film formation method described above. The lower electrode 13 has a rod shape with a width of 0.1 to 0.5 mm, and the thin film 51 has a circular shape with a diameter of about 1 mm.

  On the thin film 51, a plurality of upper electrodes 55 made of aluminum pattern wiring are formed. The upper electrode 55 has a rod shape with a width of 0.1 to 0.5 mm, and is formed so as to pass through the center of the thin film 51 so as to be orthogonal to the lower electrode 13. Therefore, the upper electrode 55 and the lower electrode 13 are completely insulated by the thin film 51 sandwiched therebetween so as not to short-circuit each other.

  FIG. 7 is a configuration diagram of the inspection device 60 that performs polling on the capacitor 50, FIG. 8 is a graph showing the IV and QV characteristics of the capacitor 50 before the rectangular wave is applied, and FIG. FIG. 10 is a graph showing the IV characteristics of the capacitor 50 during application, and FIG. 10 is a graph showing the IV and QV characteristics of the capacitor 50 after application of the rectangular wave.

  In the inspection device 60, the electric field applying device 61 is connected to the upper electrode 55 of the capacitor 50, and the lower electrode 13 is connected to the measuring device 62. Both the electric field applying device 61 and the measuring device 62 are grounded.

  The electric field applying device 61 is a device that can apply a rectangular wave and a triangular wave electric field. The measuring device 62 measures a current response when a triangular wave voltage is applied by the electric field applying device 61.

  Here, when the IV and QV characteristics are measured by applying a 150 V 20 Hz triangular wave from the electric field applying device 61 in the N2 atmosphere at room temperature using the inspection device 60, as shown in FIGS. 8A and 8B. Characteristics. The QV characteristics in FIG. 8B depict propeller-type hysteresis, suggesting that the direction of spontaneous polarization in the domain varies.

  Therefore, an electric field intermittent application step of applying a square wave of 20 Hz at ± 140 V and ± 140 V from the electric field application device 61 was performed at room temperature in an N2 atmosphere using the inspection device 60. In addition, a measurement process was performed in which a triangular wave of 20 Hz at 150 V was applied from the electric field application device 61 at an arbitrary timing between the 1000 cycles, and the electrical characteristics were measured by the measuring device 62. This arbitrary timing was equally 3 times in the first 1 to 10 cycles, 3 times equally in the next 10 to 100 cycles, and 3 times equally in the last 100 to 1000 cycles.

  As a result of this measurement, as shown in the IV characteristic of FIG. 9, the first four peaks A gradually shift to the low voltage side, and a new peak B is formed around ± 60 V after 400 cycles. It was done. This peak B is a switching current accompanying polarization inversion. When the application was further continued, the initial four peaks (hysteresis) A almost disappeared, and the current value of the new peak B increased sharply to the peak C.

  When the application of 1000 cycles of rectangular waves was completed and the triangular wave was applied again, the IV and QV characteristics were measured. As shown in the IV characteristics shown in FIG. 10A and the QV characteristics shown in FIG. 9B. In addition, electrical characteristics showing clear polarization reversal were obtained. That is, a clear DE hysteresis showing ferroelectric characteristics was obtained by repeatedly applying a rectangular wave. In this example, the coercive electric field was 160 MV / m and the remanent polarization amount was 60 mC / m 2 from a film thickness of 400 nm, an electrode area of 0.018 mm 2.

In this way, it was confirmed that the thin film 51 of the capacitor 50 exhibited ferroelectric characteristics.
That is, by applying an electric field to the thin film 51 in which the direction of the permanent dipole moment varies, the direction of the permanent dipole moment can be aligned and the parallel component in the thin film 51 can have ferroelectric characteristics.

  In Example 1 described above, the rectangular wave is repeatedly applied to develop the ferroelectric characteristics. However, the ferroelectric characteristics may be developed by other methods. For example, the deposition target substrate 10 after the thin film 51 is deposited may be heated, and the electric field may be applied while continuing this heating. In this case, in order to avoid the sublimation of the thin film 51, the deposition target substrate 10 is preferably heated to 50 ° C. to 80 ° C. or less. Even in this case, ferroelectric characteristics can be exhibited.

11 and 12 are partial front sectional views showing the configuration of the thin film forming apparatus 1A of the second embodiment. FIG. 11 shows the initial state, and FIG. 12 shows the state of the vapor deposition process.
In this thin film forming apparatus 1 </ b> A, a deposition target substrate 10 is placed on the lower surface of the holder 3, and a thin plate-like mask member 70 is placed on the lower surface. The deposition target substrate 10 and the thin plate-like mask member 70 are fixed to the holder 3 with a heat insulating material 20A having a square shape in plan view.

The mask member 70 has a thin plate shape and is formed in a square shape in plan view, and a through hole 71 is formed in a pattern shape for forming a thin film.
The heat insulating material 20 </ b> A has a through hole 21 </ b> A that is smaller than the size of the mask member 70 and larger than a region where the through hole 71 is provided in the mask member 70. The heat insulating material 20A fixes the deposition target substrate 10 and the thin plate-shaped mask member 70 at a position above the through hole 21A.

Since other configurations are the same as those of the thin film forming apparatus 1 of the first embodiment, the same components are denoted by the same reference numerals and detailed description thereof is omitted.
The thin film forming apparatus 1A of the second embodiment can form a thin film by the same process as the thin film forming apparatus 1 of the first embodiment. In the vapor deposition process, as shown in FIG. 12, the bottom surface of the heat insulating material 20 </ b> A comes into close contact with the VDF oligomer supply surface 32 of the vapor deposition source 30. And the lower surface of the mask member 70 and the upper surface (VDF oligomer supply surface 32) of the vapor deposition source 30 are closely opposed to each other with a slight gap. Therefore, the through holes 21A of the heat insulating material 20A and the through holes 71 of the mask member 70 are integrated to form a local closed space, and the gas molecules 33a detached from the VDF oligomer supply surface 32 are separated from the through holes 21A and the through holes. The film is deposited on the thin film forming surface 11 of the deposition target substrate 10 having the lowest temperature via 71.

  In this way, the thin film forming apparatus 1A of the second embodiment can form the thin film 51 of the VDF oligomer 33 on the thin film forming surface 11 of the evaporation target substrate 10 in the same manner as the thin film forming apparatus 1A of the first embodiment. Then, similarly to the first embodiment, a rectangular wave can be applied and the polarization can be reversed to obtain ferroelectric characteristics.

In correspondence between the configuration of the present invention and the above-described embodiment,
The vapor deposition substrate holding part and the moving means of the present invention correspond to the holder 3 of the embodiment,
Similarly,
The displacement allowable portion corresponds to the flexible coupling 6,
The heat insulating member corresponds to the heat insulating mask 20 and the heat insulating material 20A,
The open / close shutter corresponds to the shutter 27,
The vapor deposition source holding part corresponds to the plate 31,
The heating means corresponds to the ceramic heater 45,
The predetermined temperature corresponds to 120 degrees Celsius,
The separated state corresponds to the state shown in FIG.
The proximity state corresponds to the state shown in FIG.
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The partial front sectional view showing the configuration of the thin film forming apparatus. The top view of a heat insulation mask. The flowchart which shows the thin film formation method by a thin film formation apparatus. The partial front sectional view showing the configuration of the thin film forming apparatus. Explanatory drawing explaining a mode that VDF oligomer vapor-deposits. The top view of the capacitor manufactured using the to-be-deposited board | substrate. The block diagram of the test | inspection apparatus which polls with respect to a capacitor. The graph of the IV and QV characteristics before square wave application. The graph of the IV characteristic in the middle of rectangular wave application. The graph of the IV and QV characteristics after rectangular wave application. FIG. 5 is a partial front sectional view showing the configuration of the thin film forming apparatus of Example 2. FIG. 5 is a partial front sectional view showing the configuration of the thin film forming apparatus of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A ... Thin film formation apparatus, 3 ... Holder, 10 ... Substrate to be vapor-deposited, 11 ... Thin film formation surface, 20 ... Heat insulation mask, 20A ... Heat insulation material, 21 ... Through-hole, 27 ... Shutter, 30 ... Deposition source, 31 ... Plate, 32 ... VDF oligomer supply surface, 33 ... VDF oligomer, 45 ... ceramic heater, 51 ... thin film, 70 ... mask member, 71 ... through hole

Claims (19)

A thin film forming apparatus for forming a thin film of vinylidene fluoride oligomer by depositing a vinylidene fluoride oligomer on a thin film forming surface of a substrate to be deposited,
A deposition substrate holding unit that holds the deposition substrate;
A deposition source holding unit that holds a deposition source in which a vinylidene fluoride oligomer is disposed;
Heating means for heating the vapor deposition source;
A heat insulating member provided between the deposition target substrate and the deposition source and provided with a through hole penetrating from the deposition target substrate side to the deposition source side;
At least one of the deposition target substrate holding unit and the deposition source holding unit is moved so that the deposition target substrate and the deposition source are separated from each other, the thin film forming surface of the deposition target substrate, and the fluorination of the deposition source. A thin film forming apparatus comprising: a moving unit that changes a vinylidene oligomer supply surface to a close state that faces and is close to the heat insulating member. 2. The thin film forming apparatus according to claim 1, wherein the moving unit is configured to change from the separated state to the close state when the deposition source reaches a predetermined temperature by heating of the heating unit. The thin film forming apparatus according to claim 1, wherein the deposition target substrate holding unit is configured to fix the deposition target substrate and the heat insulating member. An opening / closing shutter that partitions the space between the heat insulating member and the vapor deposition source in the separated state and opens the space between the heat insulating member and the vapor deposition source when changing to the close state. Or the thin film forming apparatus of 3. The thin film forming apparatus according to claim 1, wherein the deposition target substrate holding unit, the heat insulating member, and the deposition source holding unit are arranged in a reduced-pressure atmosphere. 6. The thin film forming apparatus according to claim 1, wherein the thin film formed on the thin film forming surface of the deposition target substrate is patterned by the arrangement and shape of the through holes of the heat insulating member. Forming a through hole of the heat insulating member larger than a thin film forming region of the deposition target substrate;
6. The thin film forming apparatus according to claim 1, wherein a mask member for patterning a thin film formed on the thin film forming surface of the deposition target substrate is overlaid on the thin film forming surface of the deposition target substrate. 8. The displacement deposition unit according to claim 1, wherein the deposition target substrate holding unit includes a displacement allowance unit that allows the deposition target substrate and the heat insulating member to be angularly displaced along the deposition source in the proximity state. The thin film forming apparatus described in 1. A thin film forming method for forming a vinylidene fluoride oligomer thin film by depositing a vinylidene fluoride oligomer on a thin film forming surface of a substrate to be deposited,
A heating step of heating the vapor deposition source in a state where the vapor deposition source in which the vinylidene fluoride oligomer is arranged and the deposition target substrate are separated from each other;
By moving at least one of the deposition target substrate and the deposition source from a separated state where the deposition target substrate and the deposition source are separated from each other, a thin film forming surface of the deposition target substrate and a vinylidene fluoride oligomer of the deposition source A moving step in which the supply surface is changed to a close state facing and in close proximity with the heat insulating member interposed therebetween;
A thin film forming method comprising: depositing a thin film of the vinylidene fluoride oligomer on the thin film forming surface in the proximity state. The thin film forming method according to claim 9, further comprising: a shutter opening step of moving a shutter partitioning between the heat insulating member and the vapor deposition source to an open state immediately before or during the moving step. The thin film forming method according to claim 9 or 10, wherein the vapor deposition step is performed in a reduced pressure atmosphere. The thin film forming method according to claim 9, 10 or 11, wherein each of the steps is performed using the deposition target substrate at about room temperature. The method for forming a thin film according to claim 9, wherein the deposition source is a patterned one of the vinylidene fluoride oligomer. 14. The thin film forming method according to claim 9, wherein a component oriented in parallel with the deposition target substrate is present in the vinylidene fluoride oligomer thinned by the vapor deposition step. 15. A polarization inversion enabling method for enabling polarization inversion by repeatedly applying a rectangular wave having an electric field equal to or higher than a coercive electric field to a vinylidene fluoride oligomer thin film formed by the thin film formation method according to claim 9. . The vinylidene fluoride oligomer thin film formed by the thin film formation method according to any one of claims 9 to 14 enables polarization reversal by applying an electric field while heating the deposition target substrate to raise the temperature. Method for enabling polarization reversal. After performing an electric field intermittent application step of repeatedly applying a rectangular wave having an electric field equal to or higher than the coercive electric field to the vinylidene fluoride oligomer thin film formed by the thin film forming method according to any one of claims 9 to 14,
A ferroelectric property measuring method for performing a measuring step for measuring the ferroelectric property of the thin film. A thin film of vinylidene fluoride oligomer that produces four peaks when measuring IV characteristics and a propeller-type hysteresis when measuring QV characteristics. A capacitor structure in which the thin film of vinylidene fluoride oligomer according to claim 18 is interposed between two electrodes.

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