JP2008057000A - Film deposition system of lithium or lithium alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition system where, in a gas deposition device comprising an evaporation source, a hyperfine particle formation chamber, a carrier tube and a film deposition chamber with a built-in substrate arranged so as to be confronted with a nozzle, and in which hyperfine particles formed by being heated and evaporated from the evaporation source are carried to the film deposition chamber in a vacuum together with an inert gas from the hyperfine particle formation chamber with the carrier tube and are jetted from the nozzle, so as to deposit a film of the hyperfine particles on the substrate, the carrier tube and the nozzle are heated, at the upper part than the inlet end of the carrier tube, a suction tube with a diameter larger than that of the carrier tube is arranged coaxially with the carrier tube, and an annular space between the suction tube and the carrier tube is connected to an exhaust apparatus, a transferrable lithium thin film is deposited on the substrate. <P>SOLUTION: The evaporation source is an evaporation source of lithium or a lithium alloy, the substrate is made of a flexible, heat resistant synthetic resin, and, while heating the surface of the substrate to a temperature lower than the softening point of the synthetic resin, a film of the hyperfine particles of lithium or a lithium alloy is deposited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a film forming apparatus for lithium or lithium alloy, and more specifically, lithium or lithium alloy ultrafine particles are conveyed by an inert gas and sprayed from a nozzle at a high speed to form lithium or lithium alloy on an opposing substrate. The present invention relates to a film forming apparatus for lithium or lithium alloy using a gas deposition apparatus for forming a film of ultrafine particles.

FIG. 4 shows the entire gas deposition apparatus 1 according to the conventional example. In general, the ultrafine particle generation chamber 21, the transfer pipe 31, and the film formation chamber 41 are arranged in a substantially vertical direction.

In the ultrafine particle generation chamber 21, a crucible 22 having an opening diameter of 5.0 mmφ containing an evaporation material Au as an evaporation source is disposed. A coil 23 for high-frequency heating is wound around the crucible 22, and the coil 23 is connected to an AC power source 24 installed outside the ultrafine particle generation chamber 21.

Further, He gas for maintaining the interior of the ultrafine particle generation chamber 21 at a predetermined pressure and conveying the generated ultrafine particles is introduced through the mesh filter type inlet 25. That is, the He gas that has passed through the variable flow rate valve 3 from the cylinder 2 is adjusted in the gas flow rate around the evaporation source by the mesh filter type inlet 25 that can change the area and opening ratio of the filter, and the ultrafine particle generation chamber. 21 is introduced. Furthermore, a pressure gauge 6 is attached to the ultrafine particle generation chamber 21.

The conveyance pipe 31 is a straight pipe having an inner diameter of 4.3 mmφ arranged almost vertically. The lower end is inserted into the ultrafine particle generation chamber 21, the inlet end 31 a is positioned 30 mm directly above the opening end of the crucible 22, and the upper end is inserted into the film forming chamber 41. A nozzle 32 for injecting ultrafine particles is connected to the outlet end 31 b of the transport pipe 31.

The nozzle 32 has a pore 33 having an inner diameter of 0.6 mmφ, and as shown in FIG. 5, in a cross section passing through the axial center of the nozzle 32, a connection point with the outlet end 31 b of the transport pipe 31 having an inner diameter of 4.3 mmφ. To the inlet 33a of the pore 33 is narrowed in a shape that follows the trochoid curve, and a step is eliminated between the inner surfaces of the connection portion between the transport pipe 31 and the nozzle 32, and the transport pipe 31 itself has a bent portion. Combined with the fact that it is a straight pipe that does not have, the flow of ultrafine particles to be conveyed is not disturbed.

Furthermore, the conveyance pipe 31 and the nozzle 32 are heated. Returning to FIG. 4, the DC power supply 55 is connected between the upper end and the lower end so that the transport pipe 31 itself generates heat as a resistor. FIG. 6 shows another example of connection between the transfer pipe 31 and the DC power supply 55. The film formation chamber 41 is grounded, and the portion close to the ultrafine particle generation chamber 21 in the outside air exposed portion of the transfer pipe 31 and the film formation chamber 41 A resistor R is connected in parallel between the two, so that the conveyance pipe 31 can be heated with a temperature gradient. As shown in FIG. 7, a sheath heater 56 connected to another AC power source 57 is wound around the nozzle 32.

Furthermore, referring to FIG. 4, in the ultrafine particle generation chamber 21, a large-diameter suction pipe 34 sharing an axis with the transport pipe 31 is provided as a double pipe above the inlet end 31 a of the transport pipe 31. An annular space is formed between the transfer pipe 31 and the transfer pipe 31. The suction pipe 34 is provided to suck in the ultrafine particles staying in the ultrafine particle generation chamber 21 other than the portion directly above the crucible 22. The suction pipe 34 is separated from the transport pipe 31 outside the ultrafine particle generation chamber 21 and is connected to a vacuum pump 36 through a vacuum valve 35.

Furthermore, the vacuum connection part through which the double pipe of the conveyance pipe 31 and the suction pipe 34 penetrates the wall of the ultrafine particle production chamber 21 is connected with a metal bellows 37 interposed. One flange of the metal bellows 37 is fixed to the outer peripheral portion of the opening of the outer wall of the ultrafine particle generation chamber 21, and the other flange is fixed to a flange 39 provided on the suction pipe 34, whereby the inlet end 31 a of the transport pipe 31 is fixed. In order to adjust the position on the carbon crucible 22, the double pipe, that is, the vacuum pipe connection that can slightly tilt the transport pipe 31 is used.

In FIG. 4, a substrate 42 is disposed in the film forming chamber 41 so as to face the nozzle 32 at a right angle. The substrate 42 is moved in the X-axis direction indicated by the arrow and the Y-axis direction perpendicular thereto by the operation plate 9 to which the substrate 42 is attached. The operation plate 9 includes a heating mechanism (not shown) for heating the substrate 42. A vacuum pump 5 is connected to the film forming chamber 41 via a vacuum valve 4, and a vacuum gauge 7 is further attached.

The conventional example is configured as described above, and the operation thereof will be described next.

In FIG. 4, the vacuum valve 4 is opened, and the film forming chamber 41 is evacuated by the vacuum pump 5. At the same time, the vacuum valve 35 is opened and the vacuum pump 36 starts evacuation from the suction pipe 34. On the other hand, the variable flow valve 3 is opened, and the He gas in the cylinder 2 is introduced from the mesh filter type inlet 25 to the ultrafine particle production chamber 21 so as to maintain a pressure of 2 atm. The mesh filter type inlet 25 has an opening ratio of 50 so that the flow rate in the vicinity of the evaporation source is about 0.2 m / sec even if the flow rate of He gas is 40 SLM (standard liters per minute). %, An area of 85 cm ² is used.

Of the He gas flow rate 40 SLM to be introduced, the He gas ejected from the nozzle 32 via the transfer pipe 31 is about 10 SLM, and the He gas sucked by the suction pipe 34 and discharged outside the system is about 30 SLM. To do. The reason for increasing the amount of He gas to the suction pipe 34 is as follows. That is, even when the production of ultrafine particles is in a steady state, there are ultrafine particles that are discharged and stay in the ultrafine particle production chamber 21 without being sucked into the transport pipe 31, and these extra ultrafine particles are aggregated during the stay. At some time, it is sucked into the transport pipe 31 and adversely affects the formed film. Therefore, it is necessary to discharge these as soon as possible.

Under such conditions, the vacuum gauge 7 in the film formation chamber 41 shows 0.3 Torr, and a differential pressure of about 2 atm is formed between the ultrafine particle generation chamber 21 and the film formation chamber 41.

Further, the sheath heater around which the transport pipe 31 itself and the nozzle 27 are wound is energized to heat each, and a temperature gradient is applied so that the temperature is about 300 ° C. near the inlet end 31a of the transport pipe 31 and about 350 ° C. with the nozzle. To control the temperature. The substrate 42 is also heated to a temperature of 200 ° C.

Next, when the crucible 22 containing 5 gr of Au is heated to a temperature of 1500 ° C., the Au is melted and evaporated, the atmosphere of the gas is He gas having a pressure of 2 atm, so the vapor of Au becomes ultrafine particles. Most of the generated ultrafine particles rise from the opening of the crucible 22 and are sucked into the inlet 31a of the transport pipe 31 by a differential pressure of 2 atm. Since the flow rate of He gas around the evaporation source is 0.2 m / sec, the shape of the rising edge of the ultrafine particles is not disturbed, and the suction is stable.

At this time, the conveyance tube 31 that can be tilted by the metal bellows 37 is operated so that the conveyance amount of the ultrafine particles is maximized, that is, the amount of ultrafine particles that are not sucked into the conveyance tube 31 is minimized. The position of the inlet end 31a of the transport pipe 31 and the crucible 22 is adjusted. This is because the position where the conveyance amount is maximum varies slightly depending on the type of inert gas used, the amount of gas introduced, the magnitude of the differential pressure between the ultrafine particle generation chamber 21 and the film formation chamber 41, and the like. The transport amount of ultrafine particles is actually measured by the film deposition height rate (μm / sec) when the substrate 42 is fixed in the film forming chamber 41.

The ultrafine particles of Au sucked into the transport pipe 31 are transported in the transport pipe 31 heated together with the He gas, and are jetted at a high speed onto the substrate 42 heated to 200 ° C. from the heated nozzle.

Under such conditions, the substrate 42 was moved in the X-axis direction and the Y-axis direction together with the operation plate 9 to inject Au ultrafine particles onto the substrate 42. During 10 hours, the film deposition height rate was 6 μm. An Au film having no aggregate and having a particle diameter of 0.1 μm or less was formed on the Ni surface of the substrate.

JP 7-166332 A

However, lithium batteries are currently being actively developed. For example, there is a case where a lithium thin film is desired to be formed on an electrode for a lithium battery or a hybrid capacitor in order to improve their performance. In the above patent document, a gas deposition apparatus is used to form an ultrafine Au film on the nickel surface of the substrate, but the adhesion strength is very high. Even if a Li film is formed instead of an Au film, the adhesion strength seems to be very high. Actually, even when a lithium film is formed on a copper material and transferred to the electrode, the adhesion strength with copper is very high and cannot be transferred to the electrode. That is, the lithium thin film cannot be peeled off from the copper surface. On the other hand, since the purity of lithium in the ultrafine lithium film formed by the gas deposition apparatus is very high, the transfer technique is strongly desired.

The problems described above are connected to the evaporation source, the ultrafine particle generation chamber containing the inlet portion of the transport pipe located above and the introduction portion of the inert gas, the transport pipe, the outlet section of the transport pipe, and the outlet section. And a film forming chamber containing a substrate disposed opposite to the nozzle, and the ultrafine particles generated by heating and evaporation from the evaporation source together with the inert gas are vacuumed by the ultrafine particles. The film is transported to a film forming chamber and sprayed from the nozzle to form an ultrafine particle film on the substrate, and heating means are provided in both the transport pipe and the nozzle, and A suction pipe having a diameter larger than that of the transport pipe is disposed concentrically with the transport pipe above the inlet end, and an annular space between the suction pipe and the transport pipe is connected to an exhaust device. In the position device, The source is the evaporation source of lithium or lithium alloy, the substrate is made of a flexible and heat-resistant synthetic resin, and the surface temperature of the substrate is heated to a temperature lower than the softening point of the synthetic resin while This can be solved by a film forming apparatus characterized in that a film of lithium or lithium alloy is formed.

An ultrafine lithium or lithium alloy film can be formed while maintaining the purity of high-purity lithium by controlling the production process conditions. The lithium or lithium alloy film formed on the substrate can be easily transferred onto the lithium battery electrode or the hybrid capacitor electrode. The lithium secondary battery thus produced has excellent battery characteristics such as low irreversible capacity and higher electrochemical capacity than conventional ones.

Hereinafter, a lithium film forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a main part of the film forming apparatus, but other parts not shown are the same as those of the prior art of FIG.
Note that the crucible 22 containing lithium is made of tantalum in this embodiment and is heated by a resistance heating method.
Further, the purity of helium gas is set to 99.9995% or more.
In the present embodiment, a strip-shaped polypropylene m sheet is fixed to the operation panel 9 by holding screws g at four corners as a base material (also referred to as a substrate). The operation panel 9 has a built-in heating mechanism, and the nozzle 32 is also heated. The distance between the opening of the nozzle 32 and the base material m is 5 mm. The surface temperature of the base material m is controlled to be 80 ° C. by measuring the temperature with a thermocouple (not shown).

The evaporation source is heated, and ultrafine lithium is ejected from the nozzle 32. The operation panel 9 moves in the X direction. After moving a predetermined distance, the ejection from the nozzle 32 is temporarily stopped, moved a predetermined distance in the Y direction perpendicular to the X direction, and then the operation panel 9 is moved in the X direction while ejecting ultrafine lithium from the nozzle again. Move to.

As described above, a lithium film having a predetermined width is formed on the base material m.
Although the film forming chamber 41 has a glove box specification (not shown), it can be handled in an atmosphere of high-purity Ar gas. The base material m filled with Ar gas at atmospheric pressure and fixed to the operation panel 9 is removed from the holding screw g, put into a sealed container, and taken out to the outside. FIG. 2 shows a transfer device for a long base material, which will be described in detail later. An electrode for a lithium battery transferred to a gap between a pair of compression rolls 68 and 70 of a roll press machine which is a main part of this device. n (this is also approximately the same area as the base material m) and the ends are aligned and communicated. Although not shown, these compression roll machines are installed in a dry room or a glove box.
When passing between the compression rolls 68 and 70 that are pressed against each other, the lithium film Li of the lithium film forming base material Li + m is transferred onto the lithium battery electrode material n.

The first embodiment is a batch type film forming apparatus. Next, a continuous film forming apparatus or a long film forming apparatus according to a second embodiment will be described with reference to FIGS. .
3 are the same as those in FIG. 4 of the conventional example. The film forming chamber 80 is placed under vacuum. An unwinding roll 82 and a winding roll 84 are disposed in the room. Polypropylene M as a base material on which a lithium film is formed is wound around the shaft 82a of the unwinding roll 82. The base material M unwound from here is auxiliary rollers 86 and 88, a guide plate (which incorporates a heating mechanism or may itself be a heating body) 94, auxiliary rollers 90 and 92, and a winding roll. 84 is wound around a shaft 84a. A drive motor is attached to the shaft 84a.

Also in the present embodiment, the traveling speed of the base material M, the temperature of the guide plate 94, and the temperature of the nozzle 32 are set so that the surface of the polypropylene M is heated to, for example, 80 ° C. below the softening point.
When the base material M travels as indicated by an arrow and ultrafine lithium is ejected from the nozzle 32,
A lithium film is formed on the substrate M.

Next, the transfer device will be described.
In FIG. 2, the base material M formed on the unwinding roll 60 is wound, and the lithium battery electrode material n is wound on the unwinding roll 62 below. The base material M is wound around the winding roll 76 via the auxiliary rolls 64 and 72. The electrode material n is wound around a winding roll 78 via auxiliary rolls 66 and 74. Between the auxiliary rolls 64 and 72 and the auxiliary rolls 66 and 74, a pair of pressure rolls 68 and 70 of a roll press machine are disposed.
In FIG. 3, the film-winding roll 84 is handled in a high-purity Ar atmosphere or in a dry room, and is set as the winding roll 60 of the transfer apparatus in FIG. At the start of operation, the unwinding roller 62 wound with the lithium electrode material n is set at the position shown in the drawing. The ends of the base material m and the electrode material n are aligned so that the pair of pressure rollers 68 and 72 communicate with each other, the auxiliary rolls 72 and 74 are guided, and the shafts of the winding rolls 76 and 78 are engaged. I shall let you.

The shafts of the take-up rolls 76 and 78 are driven to rotate by drive motors. The pair of pressure rollers 68 and 70 are rotated counterclockwise and clockwise, respectively. When the Li film of the lithium film forming substrate Li + M passes between the rollers 68 and 70 while being pressed by the electrode material n, Li
The film is transferred to the electrode material n. Eventually, only the base material polypropylene M is wound on the roller 76. On the winding roll 78, the electrode material n to which the lithium film Li is transferred is wound. The battery characteristics of a lithium secondary battery using this electrode material n are superior to those of the prior art. This seems to be because the transfer of the lithium film to the electrode material n was almost completely performed.

As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to these, A various deformation | transformation is possible based on the technical idea of this invention.

For example, in the embodiment, a method of heating the transport pipe 31 by energizing the transport pipe 31 itself as a resistor and heating it by the generated Joule heat is employed. It is good also as a method of winding. The heating temperature of the nozzle can be changed as appropriate.

In the above embodiment, the method of inclining the transport pipe 31 is used for positioning the crucible 22 and the inlet end 31a of the transport pipe 31, but the transport pipe 31 is fixed and the crucible 22 is moved. It may be. In the above embodiment, the resistance heating method is used for heating, but a high frequency heating method may be adopted as in the conventional example of FIG.

In the above embodiment, the transport pipe 31 is a straight pipe. However, a loose bent portion may be provided as long as the flow of He gas containing ultrafine particles is not disturbed.

In the above embodiment, He is used as the inert gas. However, an inert gas other than He, for example, Ne (neon) or Ar (argon) may be used.

In the above embodiment, the lithium battery electrode is applied as a material to which the lithium film is transferred, but other members may be used. Moreover, you may apply to the electrode for hybrid capacitors.

In the above embodiment, polypropylene is applied as a synthetic resin. Polysulfone, polyphenylene oxide, polybutylene, phenol resin, urea resin, melamine resin, polyester resin, epoxy resin, silicon resin, diallyl phthalate, and polyurethane may be used.

In the above embodiment, the distance between the nozzle and the base material m or M is 5 mm. However, even if the distance is further reduced to 2 mm, a transferable and uniform film is formed. Even when the thickness was further increased to 500 mm, a uniform film that could be transferred was formed.
In addition to φ0.6 mm nozzles, wide nozzles (for example, openings of 5 mm × 0.5 mm, 30 mm × 0.3 mm, 80 mm × 1 mm, etc.) may be used. Film formation was efficient and uniform transferable film formation was achieved.

It is a schematic fracture | rupture figure which shows the principal part of the lithium film-forming apparatus using the gas deposition apparatus by 1st Embodiment of this invention. It is the schematic which shows the whole transfer apparatus used for 2nd Embodiment of this invention. Schematic which shows the principal part of the film-forming apparatus by 2nd Embodiment of this invention. Schematic diagram of conventional gas deposition equipment It is sectional drawing of the nozzle used by a prior art example. It is an electric circuit diagram for the heating of the conveyance pipe in a prior art example. It is the schematic of the sheath heater which winds the nozzle in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas deposition apparatus 21 Ultrafine particle production | generation chamber 31 Transfer pipe 32 Nozzle 41 Film formation chamber m Base material Polypropylene M Base material Polypropylene g Holding screw 68 70 Pressure roll

Claims (9)

An ultrafine particle generation chamber containing an evaporation source, an inlet part of a transport pipe located above and an introduction part of an inert gas; the transport pipe; an outlet part of the transport pipe; a nozzle connected to the outlet part; A film forming chamber containing a substrate disposed opposite to the nozzle, and the ultrafine particles generated by heating and evaporation from the evaporation source are vacuumed together with the inert gas from the ultrafine particle generating chamber by the transfer tube. The film forming chamber is sprayed from the nozzle to form an ultrafine particle film on the substrate, and heating means is provided in both the transport pipe and the nozzle, and the transport pipe A suction pipe having a diameter larger than that of the transport pipe is disposed concentrically with the transport pipe above the inlet end of the gas, and an annular space between the suction pipe and the transport pipe is connected to an exhaust device. In deposition equipment The evaporation source is the evaporation source of lithium or lithium alloy, and the substrate is made of a flexible and heat-resistant synthetic resin, and the surface temperature of the substrate is heated to a temperature lower than the softening point of the synthetic resin. A film forming apparatus characterized in that a film of lithium or a lithium alloy is formed. The lithium or lithium alloy film and the lithium battery or hybrid capacitor electrode are sandwiched between a pair of roll press machines to transfer the lithium or lithium alloy film onto the electrode. 2. The film forming apparatus according to claim 1, wherein The film forming apparatus according to claim 1, wherein the synthetic resin is any of the following:
Polypropylene, methacrylic resin, polymethyl methacrylate, polyamide,
Polycarbonate, polyacetal, thermoplastic polyester, fluorine resin, polysulfone, polyphenylene oxide, polybutylene, phenol resin, urea resin, melamine resin, polyester resin, epoxy resin, silicon resin, diallyl phthalate, polyurethane. 2. The film forming apparatus according to claim 1, wherein a distance between the nozzle and the substrate is set to 2 to 500 mm so that the substrate surface temperature is equal to or lower than a softening point of a material of the substrate. 2. The film forming apparatus according to claim 1, wherein the ultrafine particle generation chamber, the transfer pipe, and the film forming chamber are arranged on a substantially vertical line with the ultrafine particle generation chamber facing downward. The metal bellows fixes one end to the outer periphery of the opening of the ultrafine particle generation chamber so that the ultrafine particle generation chamber and the film formation chamber are connected and the transport pipe is included in the axial center, and the other end The film forming apparatus according to claim 1, wherein the film forming apparatus is fixed to an outer wall of the film forming chamber.
The film forming apparatus according to claim 1, further comprising an adjustment mechanism for adjusting a relative position between the evaporation source and an inlet portion of the transfer pipe.
. The film forming apparatus according to claim 1, wherein the introduction portion of the inert gas is a mesh filter type introduction port. The film forming apparatus according to any one of claims 1 to 8, wherein the purity of the inert gas is 99.9995% or more.

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