JP2008081830A - Film deposition apparatus and film deposition method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film deposition method by an aerosol deposition process, by which a film with a uniform thickness can be efficiently deposited. <P>SOLUTION: The film deposition method comprises: a step (a) in which raw material powder fed at an almost fixed pace is dispersed by gas to thereby generate aerosol; and a step (b) in which the aerosol generated in the step (a) is jetted from a nozzle toward a substrate to thereby deposit the raw material powder on the substrate. The step (b) is performed while controlling the relative position between the nozzle and the substrate in such a manner that on the raw material powder deposited onto the substrate by jetting the aerosol onto the substrate by moving at least either the nozzle or the substrate, raw material is superimposedly deposited through a different orbit, thus the thickness and variation of the raw material powder is offset each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film forming apparatus and a film forming method for depositing a raw material on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate.

  In recent years, with the development of devices related to micro electrical mechanical systems (MEMS), elements such as multilayer ceramic capacitors and piezoelectric actuators have been increasingly miniaturized and integrated. Therefore, research for manufacturing such an element by using a film forming technique is actively pursued.

  Recently, an aerosol deposition (AD) method, which is one of film formation techniques using the collisional adhesion phenomenon of solid particles, has attracted attention as a method for forming a ceramic film. With the AD method, aerosol generated by dispersing fine powder of raw material in gas is sprayed from a nozzle toward a substrate, and the powder is made to collide with the substrate and the film formed earlier, In this film forming method, a raw material is deposited on a substrate. Here, the aerosol means “a colloidal system in which the dispersed phase is composed of solid or liquid particles and the dispersion medium is composed of gas” (Mikiji Takahashi, “Basics of Aerosol Science”, Morikita Publishing 1st Edition, P.1). According to the AD method, since the porosity is low and a dense and strong film can be formed, the performance of the fine element as described above may be improved.

  FIG. 13 is a schematic diagram showing the tip of an aerosol injection nozzle that is generally used in the AD method. Normally, in the AD method, a nozzle 100 having a rectangular opening 101 formed at the tip is used. The size of the opening 101 varies depending on the application of the film. For example, a material having a long side of about 5 mm and a short side of about 0.35 mm is used. In the present application, a direction parallel to the short side of the opening 101 is called a scanning direction, and a direction parallel to the long side is called a nozzle width direction. When forming a film, the nozzle is usually moved in the scanning direction with respect to the substrate.

  In order to form a high-quality film having a uniform thickness and density using such an AD method, it is important to spray an aerosol having a uniform concentration from a nozzle over a long period of time. This is because if the aerosol concentration is unstable, the film formation rate becomes non-uniform, resulting in variations in film thickness.

  In order to solve such a problem, in Patent Document 1, after generating an aerosol of ceramic ultrafine particles and removing secondary particles in the aerosol by classification or crushing, only the primary particles or particles equivalent thereto are contained. It is disclosed that a high-density, dense chamber ceramic structure is obtained on a substrate without firing by spraying the substrate. Further, in Patent Document 1, in order to keep the structure at a constant thickness, ceramic ultrafine particles are dropped from a vibrating sieve to generate a continuously stable aerosol.

  Patent Document 2 discloses an aerosol generating apparatus in which a rotary table as a circulating transportation means is disposed between a powder container and an aerosol generating means. That is, an annular groove is formed on the horizontal upper surface of the rotary table, and powder is supplied from the hopper into the groove in the powder container, and then the powder overflows upward from the groove by the downstream squeegee plate. The body is removed, and in this state, the powder in the groove is sent to the aerosolization means by the rotation of the rotary table, and is supplied to the nozzle as aerosol. Patent Document 2 also discloses that the concentration of the generated aerosol is measured, and the aerosol concentration is maintained by feedback control of an aerosol generator, a gas cylinder, and the like based on the measured value ( Paragraph 0012).

  On the other hand, Patent Document 3 discloses a first scanning step (A) in which one deposition layer is formed on a substrate by spraying aerosol while scanning the spray nozzle in a predetermined direction, and the spray nozzle in the scanning direction. The scanning path changing step (B) for shifting the position of the ejection nozzle from the scanning path in the immediately preceding scanning step, and the ejection nozzle scanning in the direction along the scanning direction in the immediately preceding scanning step The second scanning step (C) for forming another deposited layer partially overlapping the deposited layer formed by the immediately preceding scanning step by ejecting the aerosol while the steps (B) and (C) are performed A film forming method including a step of alternately repeating the number of times is disclosed.

Further, in Patent Document 4, a film formation chamber, a substrate holder that is disposed in the film formation chamber and holds a substrate on which a structure is formed, an exhaust pump that exhausts the film formation chamber, and a container are disposed. An aerosol generation unit that generates aerosol by blowing up raw material powder with gas, a transport pipe that introduces the generated aerosol into the film forming chamber, and the aerosol introduced through the transport pipe is sprayed toward the substrate A film forming apparatus including a nozzle and a control unit that changes the nozzle chaotically with respect to the position of the substrate held by the substrate holder is disclosed.
JP 2001-181859 A (first page) JP 2003-275631 A (first and third pages) JP 2006-32485 A (page 2) Japanese Patent Laying-Open No. 2005-305427 (first page)

  By the way, as shown in FIG. 13, in the general nozzle, the velocity of the aerosol differs depending on the position in the opening such that the flow velocity near the center is high and the flow velocity near the end is slow. Since such a flow velocity distribution exists, the sticking probability of the raw material powder colliding with the substrate also changes according to the position in the opening. Therefore, as shown in Patent Documents 1 and 2, when the substrate is simply scanned with respect to the nozzle, the thickness of the film formed on the substrate becomes non-uniform.

  FIG. 14 shows the results of measuring the film thickness distribution of a film produced using a nozzle having a rectangular opening (long side: 5 mm), similar to the nozzle shown in FIG. In this experiment, a film was formed by reciprocating the nozzle 10 times in the short side direction with respect to the substrate. As shown in FIG. 14, according to such a scanning method, the range where the film thickness is uniform with respect to the opening width (5 mm) of the nozzle is only about 3 mm near the center. That is, the portion where the corners on both ends are raised cannot be used as a film, so the yield is very poor.

  Here, in order to reduce the influence of the flow velocity distribution in the opening, it is conceivable to move the nozzle 100 in the nozzle width direction in FIG. Thereby, the nonuniformity of the film thickness in the nozzle width direction can be offset. However, in this case, it becomes difficult to form a large-area film.

  In order to solve the above problems, as disclosed in Patent Documents 3 and 4, by devising a nozzle scanning method with respect to the substrate, the film thickness non-uniformity caused by the aerosol flow velocity distribution is offset. Can do. However, another problem occurs in such a scanning method. Here, as described in Patent Document 3, FIG. 15 shows a belt-like film while shifting the position of the nozzle by 0.2 mm so as to partially overlap the film (deposition layer) formed immediately before. The film thickness distribution of the film formed by repeating the formation is shown. At first glance, it seems that the film thickness is relatively uniform in a range of about 6 mm to 7 mm near the center. However, the film thickness error Δx in this range is about 6.5 μm, which is unexpectedly large. This error Δx is considered to be caused by variation in the concentration of aerosol ejected from the nozzle. In such a scanning method, even if feedback control is performed based on the concentration of the aerosol ejected from the nozzle, the response is delayed, so that it is difficult to obtain a uniform film thickness.

  Therefore, in view of the above points, an object of the present invention is to provide a film forming apparatus and a film forming method capable of forming a film having a uniform thickness with high yield and efficiency in film formation by an aerosol deposition method. And

  In order to solve the above problems, a film forming apparatus according to one aspect of the present invention includes an aerosol deposition method in which a raw material is deposited on a substrate by spraying an aerosol in which the raw material powder is dispersed with a gas toward the substrate. In a film forming apparatus to be used, an aerosol generating means for generating an aerosol by dispersing raw material powder supplied at a substantially constant pace with a gas, a substrate stage for fixing the substrate, and an aerosol generated by the aerosol generating means as a substrate The raw material powder that passes through different trajectories with respect to the raw material powder that is deposited on the substrate by spraying aerosol onto the substrate by moving at least one of the nozzle that injects toward the substrate and the nozzle and the substrate stage By stacking the two layers, the variation in the thickness of the raw material powder can be offset each other. To, and control means for controlling the relative position between the nozzle and the substrate.

  Further, a film forming method according to one aspect of the present invention is a film forming method by an aerosol deposition method in which a raw material is deposited on a substrate by spraying an aerosol in which the raw material powder is dispersed with a gas toward the substrate. A step (a) of generating an aerosol by dispersing the raw material powder supplied at a substantially constant pace with a gas, and an aerosol generated in the step (a) from the nozzle toward the substrate, A raw material powder deposited on the substrate by spraying aerosol onto the substrate by moving at least one of the nozzle and the substrate. On the other hand, by stacking the raw material powder through different orbits, the thickness variation of the raw material powder can be offset against each other. It is performed while controlling the relative position between Le and the substrate.

  According to the present invention, by supplying the raw material powder at a substantially constant pace, the concentration of the aerosol is kept constant and the variation in the thickness of the raw material powder is offset when spraying the aerosol onto the substrate. Alternatively, since the substrate is scanned, a dense film having a uniform thickness over a wide area and a low porosity can be obtained with a high yield.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, the same reference number is attached | subjected to the same component and description is abbreviate | omitted.
1 and 2 are schematic views showing the configuration of a film forming apparatus according to an embodiment of the present invention. FIG. 1 shows an aerosol generating unit in the film forming apparatus, and FIG. 2 shows a film forming unit in the film forming apparatus. Both are connected by an aerosol carrying tube 30 shown in FIG. The operation of the entire film forming apparatus is controlled by the control unit 35 shown in FIG.

FIG. 1A is a cross-sectional view showing the configuration of the aerosol generating unit, and FIG. 1B is a plan view showing the inside of the aerosol generating unit. As shown in FIG. 1, the aerosol generation unit includes a powder storage chamber 10 and an aerosol generation unit 20.
The powder storage chamber 10 is a chamber for storing powder, and a powder supply port 10a is provided at the upper bottom thereof, and an opening 11 is formed at the lower bottom thereof. The powder storage chamber 10 and the aerosol generation unit 20 are connected via the opening 11.

The powder storage chamber 10 is provided with a stirring blade 12 that rotates by being driven by a motor. An O (O) ring 13 a is fitted on the rotating shaft 13 of the stirring blade 12, thereby ensuring airtightness in the powder storage chamber 10. In FIG. 1B, four stirring blades 12 are shown, but the number of stirring blades may be changed as appropriate. As the material of the stirring blade 12, a hard material such as metal may be used, or a material having excellent flexibility such as rubber, silicon rubber, Teflon (registered trademark) may be used. Or you may use combining those materials, such as covering the peripheral part of a metal feather with rubber | gum.
The powder is stored in such a powder storage chamber 10, and the powder is stirred by the stirring blade 12. Thereby, the powder falls from the opening 11 and is led out to the aerosol generating unit 20.

  The powder storage chamber 10 is provided with an assist gas introduction portion 14 in order to assist or promote the powder being led out from the opening 11. The assist gas introduction unit 14 includes a pipe and a valve, and a gas cylinder is connected to the tip of the pipe, for example. In addition, as a kind of assist gas, it is desirable to use the same thing as the dispersion gas mentioned later.

The aerosol generating unit 20 is provided with a turntable 21 that rotates by being driven by a motor. An O-ring 22 a is fitted on the rotating shaft 22 of the rotating disk 21, thereby ensuring airtightness in the aerosol generating unit 20.
A groove 23 having a predetermined width and depth is formed in the turntable 21 along the circumference. The turntable 21 is disposed so that the groove 23 faces the opening 11 of the powder storage chamber 10. Such a rotating disk 21 conveys the powder at a constant rate by rotating while receiving the powder dropped from the opening 11 by the groove 23. In FIG. 1A, the cross-sectional shape of the groove 23 is a semicircle, but it may be a shape other than a semicircle, such as a rectangle or a V shape.

Further, the aerosol generating unit 20 is provided with a dispersed gas introducing unit 24 and an aerosol deriving unit 25.
The dispersed gas introduction unit 24 includes a pipe and a valve. For example, a gas cylinder is connected to the end of the pipe. As the kind of the dispersion gas, nitrogen (N ₂ ), oxygen (O ₂ ), helium (He), argon (Ar), a mixed gas thereof, dry air, or the like is used. As shown in FIG. 1 (a), the outlet of the dispersed gas introduced into the aerosol generating unit 20 by the dispersed gas introducing unit 24 is provided so as to face the groove 23 of the turntable 21. As will be described later, the dispersion gas is also referred to as a carrier gas because the powder is transported after the powder filled in the grooves 23 is dispersed.

  The aerosol lead-out portion 25 is a tube arranged so that the opening at the tip faces the groove 23, and the other end is, for example, an aerosol carrying tube shown in FIG. 2 via a pipe formed of a flexible material. 30. The aerosol transport pipe 30 is a path for transporting the aerosol from the aerosol generating unit toward the film forming unit.

As shown in FIG. 2, the film forming unit includes a film forming chamber 31, an injection nozzle 32, a substrate stage 33, and an exhaust pipe 34.
The injection nozzle 32 has an opening of a predetermined shape and size (for example, a rectangle of 5 mm × 0.35 mm), and the aerosol of the raw material powder supplied from the aerosol generation unit via the aerosol transport pipe 30 is Injected toward the substrate 41. Note that the velocity of the aerosol ejected from the ejection nozzle 32 is determined by the pressure difference between the aerosol generating unit and the film forming chamber 31.

The substrate stage 33 to which the substrate 41 is fixed is a three-dimensionally movable stage for controlling the relative position and relative speed between the substrate 41 and the ejection nozzle 32. By adjusting this relative speed, the thickness of the film formed per reciprocation is controlled.
In this embodiment, the relative position between the nozzle 32 and the substrate 41 is changed by moving the substrate stage 33 side. However, the position of the substrate 41 is fixed and the nozzle 32 side is moved. Anyway.
The inside of the film forming chamber 31 is evacuated by an exhaust pump connected to an exhaust pipe 34, thereby maintaining a predetermined degree of vacuum.

The operation of such a film forming apparatus (FIGS. 1 and 2) will be described.
In the aerosol generating unit shown in FIG. 1, desired powder is stored in the powder storage chamber 10 and the stirring blade 12 is driven. As the raw material powder, for example, ceramic powder such as PZT (lead zirconate titanate) or Al ₂ O ₃ (alumina) is used. Then, the rotating disk 21 is rotated in the aerosol generating unit 20, and the dispersed gas is sprayed on the groove 23 of the rotating disk 21.

  The powder stored in the powder storage chamber 10 falls into the groove 23 through the opening 11 while being stirred by the stirring blade 12. At that time, an air flow is formed in the opening 11 by introducing the assist gas into the powder storage chamber 10. This airflow acts as a driving force that assists or accelerates the derivation of the powder. Thereby, the powder falls into the groove 23 from the opening 11 more smoothly. The powder that has fallen into the groove 23 is deposited and conveyed in accordance with the rotational speed of the rotating disk 22. The assist gas may be introduced continuously or intermittently.

  On the other hand, in the groove 23 of the turntable 22, the dispersed gas blown there flows along the groove 23 to form an air flow. This dispersed gas flows into the inside of the aerosol lead-out portion 25 from the opening at the tip. At that time, a suction force toward the inside of the aerosol deriving unit 25 is generated around the aerosol deriving unit 25. Due to this suction force, the powder accumulated in the groove 23 flows into the aerosol outlet 25 together with the dispersed gas. The aerosol thus generated is introduced into the film forming unit shown in FIG. 2 through the aerosol outlet 25 and the aerosol transport pipe 30.

  In the film forming unit, the substrate stage 33 is scanned by a predetermined scanning method while spraying aerosol from the nozzle 32 under the control of the control unit 35. Thereby, a film 42 is formed on the substrate 41.

FIG. 3 is a diagram for explaining a scanning method of the substrate stage 33.
As shown in FIG. 3, in this embodiment, while spraying aerosol from the nozzle 32, the substrate 41 is moved in the nozzle length direction (the short side direction of the nozzle opening 32 a, the left-right direction in FIG. 3). The first scan is performed by moving the reciprocating motion one way or one way. Thereby, a strip-like film 42a having a width W is formed. Next, the nozzle 32 is moved by the pitch P in the nozzle width direction (long side direction of the nozzle opening 32a, the vertical direction in FIG. 3), and the second scanning is performed. As this pitch P, a value larger than 0 and smaller than W is set. Hereinafter, this pitch P is also referred to as a “shifting width” of the nozzle. The direction in which the nozzle 32 is moved during film formation (the left-right direction in FIG. 3) is also referred to as the “scan direction”.

  As a result, a belt-like film 42b is formed so as to overlap the film 42a formed by the first scan by a width L (L = WP). Similarly, by performing the third scan by shifting the nozzle 32 by the pitch P in the nozzle width direction, the band-shaped film 42c is formed so as to overlap the film 42b by the width L. By repeating such scanning, a film 42 is formed in a two-dimensional region on the substrate 41.

  In FIG. 3, the films 42 a, 42 b,... Are shown shifted in the left-right direction for easy explanation of the scanning method, but when actually forming the film, the scanning start position (film 42a, 42b,... And the folding position (the right ends of the films 42a, 42b,...) Are preferably aligned.

  As described above, according to the present embodiment, the aerosol generating unit shown in FIG. 1 can feed the raw material powder to the end of the aerosol deriving unit 25 at a substantially constant pace, so that the concentration of aerosol is constant. Can be kept in. In addition, the aerosol can be adjusted to a desired concentration by adjusting the rotation speed of the turntable 21. Accordingly, it is possible to supply an aerosol having a stable concentration or an aerosol having a desired concentration to the nozzles of the film forming unit for a long time.

  Further, according to the present embodiment, the aerosol shown in FIG. 2 is sprayed onto the substrate so as to overlap a part of the previously formed film, so that the film thickness non-uniformity due to the flow velocity distribution in the aerosol is generated. Sex can be offset. Therefore, a film having a uniform thickness over a wide area can be manufactured with high yield.

<Experiment 1>
Using the film forming apparatus (FIGS. 1 and 2) according to one embodiment of the present invention, a PZT film was produced under the following conditions, and the film thickness distribution was measured. The scanning method is different between Example 1 and Comparative Example 2.
Raw material powder: PNN-PZT powder manufactured by Furuuchi Chemical Co., Ltd. Substrate: 1 mm thick YSZ (yttrium stabilized zirconia) substrate Carrier gas: oxygen (O ₂ ) 6 liter / min Nozzle opening: 5 mm × 0.35 mm

(Example 1)
As shown in FIG. 4, every time the nozzle 32 is reciprocated once in the scanning direction (one way: 10 mm), the film forming operation of shifting the nozzle 32 by 1 mm in the nozzle width direction is repeated 30 times, so that 35 mm × A 10 mm film was formed. In Example 1, the rotation speed of the turntable 21 shown in FIG. 1 was 0.5 rotation.

  Here, when the film is formed in this way, the regions of both ends 5 mm in the nozzle width direction are tapered. Therefore, in Example 1, the mask 51 was previously arranged in the region, and the mask 51 was removed after the film formation to obtain a film 52 of about 25 mm × 10 mm. Note that the regions at both ends are tapered because the number of scans of the nozzles in these regions is smaller than in the central region.

(Comparative Example 1)
As shown in FIG. 5, the film forming operation of reciprocating the nozzle 32 once in the scanning direction (one way 10 mm) was repeated 10 times without shifting the film forming region. Thereby, a film 53 of 5 mm × 10 mm was obtained on the substrate 41. In Comparative Example 1, the rotation speed of the turntable 21 shown in FIG. 1 was 0.5 rotation.

  About the film | membrane 52 of Example 1 and the film | membrane 53 of the comparative example 1, the film thickness distribution in a scanning direction and a nozzle width direction was measured using the stylus type surface shape measuring device Dektak 6M made from ULVAC, Inc. . In this case, as shown in FIG. 6, in order to suppress errors due to the surface shape of the substrate 41, a region on the film 54 and a region on the substrate 41 where the film 54 is not formed (reference region). The thickness of the film 54 was obtained by subtracting the measurement value (reference value) obtained by the reference scan from the measurement value obtained by the measurement scan.

FIG. 7 shows the film thickness distribution of the film 52 shown in FIG. 8 shows the film thickness distribution of the film 53 shown in FIG.
As shown in FIG. 8, in Comparative Example 1, the result that the film thickness near the center of the film 53 and at the end part was thin was obtained. This is considered because the velocity and concentration of the aerosol are different in the cross section of the nozzle 32 in the long side direction. That is, in the vicinity of the center of the nozzle 32, since the aerosol flow velocity is too high, the probability that the raw material powder can adhere to the substrate is lowered. On the other hand, at the end of the nozzle 32, it is considered that the film thickness is thin because the aerosol concentration is low.
On the other hand, as shown in FIG. 7, in Example 1, a substantially uniform film thickness was obtained in almost the entire region of the film 52.

FIG. 9 shows the average film thickness and film thickness variations in the nozzle width direction and the scan direction for the film 52 of Example 1 and the film 53 of Comparative Example 1, respectively. Here, in calculating the average film thickness and the variation in film thickness, the following equations (1) and (2) were used.
Average film thickness = {(maximum film thickness in the film) + (minimum film thickness in the film)} / 2 (1)
Variation in film thickness = {(maximum film thickness) − (average film thickness)} / (average film thickness) (2)

  The maximum film thickness in the nozzle width direction of the film 53 of Comparative Example 1 was 6.7 μm, and the minimum film thickness was 2.5 μm. Therefore, from the formulas (1) and (2), the average film thickness was 4.6 μm and the film thickness variation was ± 46%. On the other hand, the average film thickness in the nozzle width direction of the film 52 of Example 1 was 5.2 μm, and the variation in film thickness was ± 17%. As described above, in Example 1, the film thickness variation was smaller than that of Comparative Example 1 by forming the film by shifting the nozzle by 1 mm every time the nozzle was reciprocated once.

Further, when the film thickness variation was calculated also in the scanning direction, the film thickness variation of Comparative Example 1 was ± 17%, whereas the film thickness variation of Example 1 was suppressed to as low as ± 9%. It was.
Further, paying attention to the average film thickness, in Example 1, the average film thickness in the scan direction is 4.7 μm, whereas the average film thickness in the nozzle width direction is 5.2 μm, which is large between the two. There was no difference. That is, it can be seen that a film having a uniform thickness as a whole is formed regardless of the direction. On the other hand, in Comparative Example 1, the average film thickness in the scanning direction was 2.8 μm, whereas the average film thickness in the nozzle width direction was 4.6 μm, and a difference of approximately 2 μm occurred. That is, a film thickness distribution corresponding to the direction has occurred in the entire film.

<Experiment 2>
Using a film forming apparatus having a raw material powder quantitative supply mechanism and a film forming apparatus not having the mechanism, a PZT film was produced and an experiment was conducted to measure the film thickness distribution. The film forming conditions (types of raw material powder, substrate, and carrier gas) are the same as those in Experiment 1.

(Example 2)
As the film forming apparatus, a film forming apparatus (FIGS. 1 and 2) having a raw material powder quantitative supply mechanism was used. As the scanning method, as shown in FIG. 3, every time the nozzle 32 was reciprocated once in the scanning direction, the film forming operation of shifting 0.5 mm in the nozzle width direction was repeated 50 times. Thereby, a 10 mm × 20 mm film was formed on the substrate. In Example 2, the rotation speed of the turntable 21 shown in FIG. 1 was 0.5 rotation.

(Comparative Example 2)
As the film forming apparatus, an apparatus having no quantitative powder supply mechanism was used. That is, an aerosol generating unit that generates an aerosol by placing raw material powder in a container and introducing carrier gas into the container to wind up the raw material powder was connected to the film forming unit shown in FIG. The scanning method during film formation is the same as that in the second embodiment. Thereby, a 10 mm × 20 mm film was formed on the substrate.

  About the film | membrane obtained by Example 2 and the comparative example 2, the film thickness distribution in a scanning direction and a nozzle width direction is measured, and based on them, average film thickness and film thickness using Formula (1) and (2) The variation of was calculated. The calculation result is shown in FIG. The method for measuring the film thickness distribution is the same as in Experiment 1.

  Referring to FIG. 9, as apparent from a comparison between Example 1 and Example 2, in Example 2, the “shift width” of the nozzle was made shorter than that in Example 1 (1 mm) ( 0.5 mm), variation in film thickness could be further reduced in both the scanning direction and the nozzle width direction.

  However, in Comparative Example 2, although the film was formed by the same scanning method as in Example 2, the variation in film thickness was extremely large in both the scanning direction and the nozzle width direction. This is presumably because the aerosol generation part did not have a raw material powder quantitative supply mechanism, and therefore the aerosol concentration could not be kept constant. In this case, it was confirmed that the merit of forming the film while shifting the nozzle was not utilized at all.

<Experiment 3>
As a film forming apparatus, a film forming apparatus (FIGS. 1 and 2) having a raw material powder quantitative supply mechanism was used, and an experiment was conducted in which the amount of raw material powder supplied was changed. The film forming conditions (types of raw material powder, substrate, and carrier gas) are the same as those in Experiment 1.

(Examples 2 to 4)
In Example 2 described above, the rotation speed was 0.5 rotation / minute. Based on this, in Example 3, the rotation speed was 0.25 rotation / minute (half of Example 2), and in Example 4, it was 1 rotation / minute (twice that of Example 2).

(Example 5)
As in Example 1, the “shift width” of the nozzle in the film forming unit was set to 1 mm for one reciprocal film formation, and the rotation speed was set to 0.25 rotation / minute (half of Example 1).

FIG. 10 shows average film thickness and film thickness variations in the scan direction and nozzle width direction of the films obtained in Examples 2 to 5. Note that these acquisition methods are the same as in Experiment 1.
As shown in FIG. 10, in Examples 2 to 4 in which the shift width was set to 0.5 mm, the variation in film thickness was suppressed to be low in both the scan direction and the nozzle width direction. Further, focusing on the average film thickness, the average film thickness was increased as the rotation speed of the rotating disk was increased, that is, as the amount of raw material powder supplied per unit time was increased. As shown in FIG. 11, in Examples 2 to 4 (shift width 0.5 mm), it was confirmed that there is a proportional relationship between the average film thickness and the rotation speed of the rotating disk. On the other hand, in Examples 1 and 5 in which the shift width is set to 1 mm, the average film thickness increase rate (straight line) with respect to the rotational speed is smaller than those in Examples 2 to 4, but the average film thickness and the rotating disk are also used. It was confirmed that there was an almost proportional relationship with the rotation speed of the.

  The results of Experiment 3 are summarized as follows. That is, by setting the shift width to 1 mm or less and the rotation speed to 0.25 revolutions / minute or more, the variation in the film thickness in the nozzle width direction is within ± 25%, preferably within ± 20%, and more preferably. Can be kept within ± 10%. Further, under the same conditions, the variation in film thickness in the scanning direction can be kept within ± 20%, preferably within ± 10%.

  From Experiment 3, the following became clear. That is, since the variation in the film thickness can be reduced by setting the nozzle shift width small, the film quality and the yield can be improved. However, if the shift width is simply reduced, the number of times of film formation is increased per unit area, so that the film becomes thicker. Therefore, by adjusting the rotation speed of the rotating disk, the thickness of the film formed per time (one reciprocation or one way) can be controlled, so that the entire film can have a desired thickness. That is, by using two parameters of the nozzle shift width in the film forming unit and the rotation speed of the rotating disk (feed rate of raw material powder) in the aerosol generating unit, the film quality (film thickness variation) and film thickness It becomes possible to control both.

<Experiment 4>
A PZT film was formed using a known coating method, and the average film thickness and film thickness variation were measured and compared with the film produced in Example 3.
(Comparative Example 3)
The same PZT powder as in Example 3 was prepared as a raw material powder, and α-terpineol in which ethylcellulose was dissolved was prepared as a binder. A mixture of them was applied to a YSZ substrate and baked at 1000 ° C. for 2 hours to produce a PZT film, which was used as the film of Comparative Example 3.

The films of Example 3 and Comparative Example 3 were cut along a plane orthogonal to the substrate, and a cross section was obtained by focused ion beam (FIB) processing. And the cross-sectional photograph was image | photographed with the scanning electron microscope (SEM), and the porosity in each film | membrane was calculated | required using following Formula (3) based on this cross-sectional photograph.
Porosity = (Area of pores in cross section) / (Area of cross section) (3)

  As shown in FIG. 12, in both Example 3 and Comparative Example 3, there was no significant difference in the average film thickness and the variation in film thickness. That is, a film having a uniform thickness can be formed by a conventional coating method. However, while the porosity of the film of Comparative Example 3 is 20%, the porosity of the film of Example 3 is as very small as 6%. This is due to the film formation mechanism peculiar to the AD method in which the new surface generated when the raw material powder collides with the lower layer. From this experiment, the AD method has a low porosity and is dense. It was confirmed that a simple film can be formed.

  In the present embodiment described above, a scanning method is used in which the nozzle is shifted by a predetermined width every time when one-way or one-way film formation is performed. However, for the raw material powder deposited on the substrate by spraying the aerosol, the raw material powder is accumulated and accumulated through different orbits, so that the dispersion of the thickness of the raw material powder cancels each other out. Any other scanning method may be used as long as it can be drawn. For example, the substrate may be scanned so that the substrate moves in a combination of two types of rotation (revolution and rotation), or the nozzle may be scanned so as to draw a chaotic trajectory. good.

  The present invention can be used in a film forming method and a film forming apparatus for depositing a raw material on a substrate by spraying an aerosol in which the raw material powder is dispersed toward the substrate.

It is a schematic diagram which shows the structure of the aerosol production | generation part in the film-forming apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the structure of the film-forming part in the film-forming apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the scanning system performed in the film-forming apparatus which concerns on one Embodiment of this invention. 6 is a diagram for explaining a scanning method in Embodiment 1. FIG. 10 is a diagram for explaining a scanning method in Comparative Example 1. FIG. It is a figure for demonstrating the measuring method of film thickness distribution. FIG. 4 is a diagram showing a film thickness distribution in the film of Example 1. 6 is a view showing a film thickness distribution in a film of Comparative Example 1. FIG. It is a table | surface which shows the film thickness characteristic in the film | membrane of Examples 1 and 2, and Comparative Examples 1 and 2. It is a table | surface which shows the film thickness characteristic in the film | membrane of Examples 1-5. It is a figure which shows the relationship between the rotational speed of the turntable in the film | membrane of Examples 1-5, and an average film thickness. It is a table | surface which shows the film thickness characteristic and porosity of the film | membrane of Example 3 and Comparative Example 3. It is a schematic diagram which shows the front-end | tip part of an aerosol injection nozzle. It is a figure which shows the film thickness distribution of the film | membrane produced using the nozzle which has a rectangular opening. It is a figure which shows the film thickness distribution of the film | membrane formed by the scanning system which shifts a nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Powder storage chamber 10a Powder supply port 11 Opening 12 Stirrer blade 12a Lowermost part 13 of stirring blade, 22 Rotating shaft 13a, 22a O (O) ring 14 Assist gas introduction part 20 Aerosol production | generation chamber 21 Turntable 23 Groove 24 Dispersion Gas introduction part 25 Aerosol lead-out part 30 Aerosol transport pipe 31 Film formation chamber 32 Nozzle 32a Nozzle opening 33 Substrate stage 34 Exhaust pipe 35 Control part 41 Substrate 42, 42a, 42b, ..., 52, 53, 54 Film 51 Mask

Claims (19)

In a film forming apparatus using an aerosol deposition method in which a raw material powder is deposited on a substrate by spraying an aerosol in which the raw material powder is dispersed with a gas toward the substrate,
Aerosol generating means for generating an aerosol by dispersing the raw material powder supplied at a substantially constant pace with a gas;
A substrate stage for fixing the substrate;
A nozzle for injecting the aerosol generated by the aerosol generating means toward the substrate;
By moving at least one of the nozzle and the substrate stage, the raw material powder deposited on the substrate by spraying aerosol onto the substrate is accumulated on the substrate through different tracks. By the control means for controlling the relative position of the nozzle and the substrate, so that the variation in the thickness of the raw material powder is mutually offset,
A film forming apparatus comprising:   Of the nozzle and the substrate stage, the control means draws a trajectory in which the raw material powder deposited on the substrate is substantially parallel and partly overlapped with the trajectory of the raw material powder previously deposited on the substrate. The film forming apparatus according to claim 1, wherein at least one of the two is moved.   2. The control unit according to claim 1, wherein at least one of the nozzle and the substrate stage is moved so that a trajectory combining a plurality of rotational movements is drawn by the raw material powder deposited on the substrate. Deposition device.   The film forming apparatus according to claim 1, wherein the control unit moves at least one of the nozzle and the substrate stage so that a chaotic orbit is drawn by the raw material powder deposited on the substrate.   The film forming apparatus according to claim 1, wherein the control unit changes a supply pace of the raw material powder supplied in the aerosol generation unit. The aerosol generating means,
A powder storage chamber for storing raw material powder, wherein the powder storage chamber in which an opening is formed;
A rotating body in which a groove having a constant width and depth is formed on a circumference, wherein the rotating body is disposed so that a part of the groove faces the opening of the powder storage chamber; ,
A gas supply means for supplying a gas for dispersing the raw material powder to a second region different from the first region facing the opening of the powder storage chamber in the groove;
Including
The raw material powder with which the 1st area | region of the groove | channel of the said rotary body is filled through the opening of the said powder storage chamber by rotating the said rotary body is conveyed by the said 2nd area | region. The film-forming apparatus of any one of -5.   The film forming apparatus according to claim 6, wherein the control unit changes a supply pace of the raw material powder conveyed to the second region by changing a rotation speed of the rotating body. In the film forming method by the aerosol deposition method in which the raw material powder is deposited on the substrate by spraying the aerosol in which the raw material powder is dispersed by the gas toward the substrate,
A step (a) of generating an aerosol by dispersing the raw material powder supplied at a substantially constant pace with a gas;
A step (b) of depositing raw material powder on the substrate by spraying the aerosol generated in the step (a) from the nozzle toward the substrate;
Comprising
The step (b) moves the at least one of the nozzle and the substrate, so that the raw material powder passes through different trajectories with respect to the raw material powder deposited on the substrate by spraying aerosol onto the substrate. It is performed while controlling the relative position of the nozzle and the substrate so that the variation in the thickness of the raw material powder is offset by mutually depositing,
Film forming method.   In the step (b), the nozzles and the substrate are arranged so as to draw a trajectory in which the raw material powder deposited on the substrate is substantially parallel and partially overlapped with the trajectory of the raw material powder previously deposited on the substrate. The film-forming method of Claim 8 including moving at least one.   The step (b) includes moving at least one of the nozzle and the substrate such that a raw material powder deposited on the substrate forms a trajectory combining a plurality of rotational movements. 9. The film forming method according to 8.   9. The process of claim 8, wherein step (b) comprises moving at least one of the nozzle and the substrate such that a chaotic trajectory is drawn by the raw material powder deposited on the substrate. Membrane method.   The film-forming method of any one of Claims 8-11 in which a process (a) includes changing the supply pace of raw material powder.   In the step (a), the raw material powder is filled by filling the raw material powder into the grooves of the rotating body in which grooves having a certain width and depth are formed on the circumference and rotating the rotating body. The raw material powder is conveyed from the first region to a second region different from the first region, and the raw material powder is dispersed in the gas in the second region. The film-forming method of any one of Claims.   The film forming method according to claim 13, wherein the step (a) includes changing a supply pace of the raw material powder conveyed to the second region by changing a rotation speed of the rotating body.   The film forming method according to claim 8, wherein the step (b) includes depositing a raw material powder on the substrate so as to have a thickness of 10 μm or less.   A film having a thickness of 0.1 μm or more and 10 μm or less manufactured by an inorganic material by using the film forming method according to claim 8, wherein the porosity is less than 20%. There is an inorganic material film with a thickness variation within ± 25%.   The inorganic material film according to claim 16, wherein the variation in thickness is within ± 20%.   The inorganic material film according to claim 16, wherein the thickness variation is within ± 10%.   The inorganic material film according to claim 16, wherein the porosity is less than 5%.

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