JP2006021332A - Functional element, its manufacturing method, fluid discharging head, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional element which enables sure sealing of an opening even when a hollow structural part is formed by sealing the opening, and which can attain ensuring of function realization by the hollow structural part. <P>SOLUTION: In the functional element 1 which has the hollow structural part 2 formed by sealing the opening 4, the opening 4 is sealed by a sealing film 6 formed by physical vapor deposition. The sealing film 6 is formed when a film formation temperature at the time of physical vapor deposition or an annealing temperature after film formation rises up to not lower than a reflow temperature of a film forming material of the sealing film 6. The film forming material of the sealing film 6 is made to melt to bring about a flow by surface tension. Filling of the film forming material of the sealing film 6 into the opening 4 is facilitated accordingly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a functional element having a hollow structure portion, a method for manufacturing the functional element, a fluid ejection head including an ink jet head configured using the functional element, and a printing apparatus including an ink jet printer apparatus.

  In recent years, functional elements having a hollow structure formed by a thin film forming technique are being used. The “thin film formation technique” refers to a technique for forming a thin film by performing vapor deposition, sputtering, etching, or the like, for example, as used when performing fine processing on a silicon semiconductor substrate in a semiconductor manufacturing process. The “functional element having a hollow structure part” means an element in which the internal element of the hollow structure part or the inner surface or surface of the structure part shows some response to an input signal. In addition, a case where any gas, liquid, or solid is injected into the hollow structure portion is included. The hollow structure portion may be completely sealed or may be partially opened. As an example of such a functional element, so-called MEMS (Micro Electro Mechanical Systems) is known.

  By the way, in the functional element described above, the hollow structure portion is generally formed by sealing the opening used for the removal after removing the sacrificial layer. Specifically, for example, when a diaphragm type semiconductor device is taken as an example, it is known to form in the following procedure (for example, see Patent Document 1). That is, a first etching resistant layer is laminated on the surface of the silicon substrate, and an etching layer that becomes a sacrificial layer is laminated in a predetermined region on the surface of the first etching resistant layer. And after laminating | stacking the 2nd etching-resistant layer which has many fine openings on the surface of the etching layer, an etching layer is etched from the opening group of a 2nd etching-resistant layer. As a result, a space is formed between the first etching resistant layer and the second etching resistant layer. After the formation of the space, a sealing film is laminated on the surface of the second etching resistant layer to seal a small opening group of the second etching resistant layer. Through the above procedure, a diaphragm structure is realized in which a diaphragm is formed by the second etching resistant layer and the sealing film, and a sealed space serving as a hollow structure portion is formed inside the diaphragm.

Japanese Patent Laid-Open No. 2002-343979

  However, in the conventional functional element, when the opening is sealed to form the hollow structure portion, the thickness (gap height) of the sacrificial layer that becomes the hollow structure portion and the size (diameter) of the opening to be sealed ) Or depending on conditions such as depth, the opening may not be sufficiently filled with the film forming material of the sealing film, and voids (bubbles) may be generated. The generation of such voids should be avoided because it makes the sealing of the opening incomplete, makes it difficult to seal the hollow structure part, and also leads to a functional deterioration of the functional element. . In this regard, it is conceivable that the metal film used for sealing flows under high temperature and high pressure to eliminate voids, but there is also a concern that the pressure may adversely affect the hollow structure portion. Further, Patent Document 1 discloses a technique for sealing a porous polysilicon material with a silicon nitride film. In such sealing by chemical vapor deposition (hereinafter abbreviated as “CVD”), There are difficulties such as being deposited in the cavity and being unable to select polysilicon as a sacrificial layer. For these reasons, it is hoped that the functional element having a hollow structure portion has few restrictions and is surely sealed with a simple process without being affected by the thickness of the sacrificial layer. It is rare.

  Therefore, the present invention makes it possible to reliably seal the opening even when the opening is sealed after the sacrificial layer is removed to form a hollow structure, and the function can be reliably realized by the hollow structure. It is an object of the present invention to provide a functional element that can be realized and a manufacturing method thereof, a fluid discharge head including an ink jet head, and a printing apparatus including an ink jet printer apparatus.

  The present invention is a functional device devised to achieve the above object, wherein the opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure portion, The film is formed by raising the film formation temperature during the physical vapor deposition or the annealing temperature after the film formation to a temperature higher than the reflow temperature of the film formation material of the sealing film.

  Further, the present invention provides a functional element manufacturing method devised to achieve the above object, a step of forming an opening, a step of forming a sealing film for sealing the opening by physical vapor deposition, The hollow structure portion is formed by a step of raising a film formation temperature during the physical vapor deposition or an annealing temperature after the film formation to a temperature higher than a reflow temperature of a film forming material of the sealing film.

  Further, the present invention is a fluid discharge head devised to achieve the above object, wherein the opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure portion, and the sealing is performed. The stop film is formed by raising the film formation temperature in the physical vapor deposition or the annealing temperature after the film formation to a temperature higher than the reflow temperature of the film formation material of the sealing film.

  Further, the present invention is a printing apparatus devised to achieve the above object, wherein the opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure portion, and the sealing The film is formed by raising the film formation temperature in the physical vapor deposition or the annealing temperature after the film formation to a temperature higher than the reflow temperature of the film forming material of the sealing film.

  According to the functional element having the above configuration, the method for manufacturing the functional element having the above procedure, the fluid ejection head having the above configuration, and the printing apparatus having the above configuration, the sealing film has a temperature equal to or higher than the reflow temperature of the film forming material of the sealing film. It is formed at the film temperature or the annealing temperature after film formation. Here, the “reflow temperature” means a temperature at which the film forming material of the sealing film melts. For example, when the film forming material is aluminum (Al), about 350 ° C. corresponds to this. When the sealing film is formed at a temperature equal to or higher than the reflow temperature or annealed after the film is formed, the film forming material of the sealing film melts and flows due to surface tension. Therefore, when the opening is sealed by forming the sealing film, it is easy to fill the film forming material of the sealing film into the opening or the void formed at the time of film formation on the opening. Thus, it is possible to avoid the generation of voids when sealing the opening, and the opening can be reliably sealed.

  In the present invention, even when the opening is sealed to form the hollow structure portion, void generation can be avoided and the opening can be reliably sealed. Can be planned. This can be said to lead to improvement in performance (function) and reliability of the functional element. In addition, in a device such as an ink jet head that requires airtightness, for example, the sealing (package) cost often accounts for more than half of the product price. The need for (wafer level packaging) technology is high, and it can be said that the technical value of the present invention that can realize this technology is high. In addition, by realizing wafer level packaging, it can be expected that device miniaturization (high integration) can be easily realized.

  Hereinafter, a functional element and a manufacturing method thereof, a fluid discharge head, and a printing apparatus according to the present invention will be described with reference to the drawings.

[Description of functional elements]
First, a schematic configuration of the functional element will be described. As described above, the functional element includes all of the elements having the hollow structure portion, and an example thereof is shown in FIG. FIG. 1 is an explanatory diagram showing an example of a schematic configuration of a functional element according to the present invention.

  As shown in the figure, the functional element 1 described here has a hollow structure portion 2. A vibrator 3 is formed in the hollow structure portion 2, and a voltage is applied to an electrode (not shown) to vibrate the vibrator 3, or a change in capacitance with the electrode (not shown). The vibration of the vibrator 3 can be converted into an electric signal. The vibrator 3 is not necessarily formed. For example, a layer covering the hollow structure portion 2 may function as a diaphragm.

  The hollow structure portion 2 is formed by bonding a plurality of substrates, etching the substrates, or so-called sacrificial layer etching. Here, the case of sacrificial layer etching will be described. That is, an etching layer serving as a sacrificial layer is laminated at a location where the hollow structure portion 2 is formed, and further an etching resistant layer 5 having an opening 4 is laminated on the surface of the etching layer, and the etching layer is etched from the opening 4. After the removal, the opening 4 used for the removal is sealed.

  The opening 4 is sealed by forming a sealing film 6 at the formation location. The sealing film 6 may be formed by physical vapor deposition (hereinafter abbreviated as “PVD”). As PVD, for example, vacuum deposition, sputtering, and the like are known, but it is particularly desirable to perform by metal sputtering. If there is a film formation on the hollow structure portion 2 during the sealing process, the device characteristics of the functional element 1 may be changed, but this problem is lessened by metal sputtering. Also, PVD is suitable for sealing the opening 4 with the sealing film 6 because the film forming material has high straightness.

  A cover layer 7 is laminated on the sealing film 6 that seals the opening 4 to prevent intrusion of outside air, fluid, or the like and prevent deterioration of the sealing film. The cover layer 7 may be formed by CVD. The cover layer 7 only needs to be made of at least one CVD film, and may be made by laminating a plurality of CVD films.

  By the way, if the opening 4 is simply sealed by metal sputtering, as will be described in detail later, voids may occur due to the shadowing effect, and an air path that passes between the hollow structure portion 2 and the outside may remain. There is. For this reason, in the functional element 1 described here, the film forming temperature when PVD is performed on the sealing film 6 or the annealing temperature after film forming is higher than the reflow temperature of the film forming material of the sealing film 6. ing. Furthermore, for the hollow structure portion 2 formed by sealing the opening 4 with the sealing film 6, prior to PVD for the sealing, the film formation temperature or film formation at the time of the PVD is performed. A preheating treatment at a temperature equal to or higher than the later annealing temperature is performed. Details of these temperatures and heat treatment will be described later.

[Description of Method for Manufacturing Functional Element]
Next, a method for manufacturing the functional element 1 having the above configuration will be described. In particular, here, the sealing of the opening 4 and the film formation temperature, heat treatment, and the like during PVD for the sealing will be mainly described. 2 and 4 are explanatory views showing an outline of a method for manufacturing a functional element according to the present invention, and FIG. 3 is an explanatory view showing an outline of a conventional example to be compared.

  Even when the functional element 1 having the above-described configuration is manufactured, the formation of the opening 4 and the sacrificial layer etching using the opening 4 may be performed in the same procedure as in the prior art. Then, after the sacrificial layer is removed by sacrificial layer etching, the sealing film 6 is formed to seal the opening used for the sacrificial layer etching.

  The opening 4 to be sealed at this time may be formed in a tapered shape whose side cross-sectional shape becomes narrower toward the hollow structure portion 2 as shown in FIG. When formed into a tapered shape, the tapered inclined surface preferably has an angle with respect to the vertical direction (inclination angle) of 30 ° or more. Such a tapered inclined surface may be formed as described below. For example, after forming a resist film patterned at the opening formation position, isotropic etching is performed while the resist film is retracted, and then reactive ion etching (hereinafter referred to as “RIE”) is performed. Thus, it is conceivable to form a tapered inclined surface. In this case, the inclination angle and depth of the tapered inclined surface are controlled to a desired angle and depth by appropriately adjusting processing parameters (processing time, processing conditions, etc.) during isotropic etching or RIE. It is possible. In addition, a tapered inclined surface is formed by preliminarily tapering the opening wall of the resist film with a halftone mask, three-dimensional lithography, etc., and appropriately setting an etching rate ratio with the resist film. It is possible. Further, even if the opening is performed only by RIE without performing isotropic etching, it is possible to form a tapered inclined surface by proceeding with etching while forming a by-product on the side wall.

  By the way, in general, when the opening 4 is simply sealed by metal sputtering, as shown in FIG. 3A, an air path (air passage) 8 remains due to the shadowing effect, and the sealing is incomplete. It may become a thing. In addition, as shown in FIG. 3B, voids 9 are generated, which may cause incomplete sealing.

  Therefore, the sealing film 6 for sealing the opening 4 is formed by the procedure described below. Here, a case where the opening 4 is sealed by metal sputtering using Al to form the hollow structure portion 2 will be described as an example.

  In the case of sealing the opening 4, first, before the Al sputtering for forming the sealing film 6, sacrifice is performed at a film formation temperature when performing the Al sputtering or a temperature equal to or higher than an annealing temperature after the Al sputtering. A preheating treatment is performed to heat the space after the layer is removed. Details of the film formation temperature and the annealing temperature will be described later. By performing such preheating treatment, moisture, impurities, etc. existing in the space after the sacrificial layer is removed, that is, those that may cause voids, are removed from the space through the opening 4 to the outside. Will be.

  After the preheating treatment, a titanium nitride (TiN) film is sputtered to a thickness of, for example, about 20 nm to prevent Al diffusion on the etching resistant layer 5 in which the opening 4 is formed. A titanium (Ti) film as an adhesion layer is sputtered with a thickness of about 5 nm, for example. Thereafter, the Al film is sputtered at a temperature of about 500 nm, for example, at a temperature used in normal Al sputtering (hereinafter, this temperature is referred to as “low temperature”), and then the Al film is formed at a temperature equal to or higher than the reflow temperature of the Al film. For example, sputtering is performed with a thickness of about 500 nm. Through such a procedure, the Al film of 500 nm thickness + 500 nm thickness becomes the sealing film 6 to seal the opening 4.

  That is, when the opening 4 is sealed, the sealing film 6 is formed at a film forming temperature equal to or higher than the reflow temperature of Al as the film forming material. Here, the “reflow temperature” means a temperature at which the film forming material of the sealing film melts. For example, when the film forming material is Al, about 350 ° C. corresponds to this.

The Al film to be the sealing film 6 does not necessarily need to be formed separately in two times, a low temperature and a temperature higher than the reflow temperature. Here, when the sealing film 6 is sputtered only at a temperature equal to or higher than the reflow temperature while omitting the low temperature, Al as the film forming material of the sealing film 6 melts and causes flow due to surface tension. 4A to 4E in order, the upper surface of the sealing film 6 is flattened by the surface tension, and the bottom surface of the etching resistant layer 5 facing the hollow structure portion 2 is sandwiched. It bridges away from the upper surface (gap base film). Therefore, even when the opening 4 is sealed by forming the sealing film 6, unlike the case of sealing by simple Al sputtering, filling of the film forming material of the sealing film 6 into the opening 6 is performed. Thus, the sealing film 6 having a substantially flat surface and no voids can be formed, and the opening 4 can be reliably sealed. In addition, since the bottom surface of the sealing film 6 bridges due to the surface tension of the Al film, the opening 4 can be sealed without the sealing film 6 contacting the gap base film.
Prior to this, if sputtering is performed at a low temperature of about 500 nm, surface tension does not act on the bottom surface of the Al film, and it is possible to ensure contact with the gap base film without bridging. Further, an Al film having a thickness of about 1 μm may be sputtered at a low temperature, and an annealing process may be performed after the film formation. Even in this case, the annealing temperature is Al, which is a film forming material for the sealing film 6. If the temperature is equal to or higher than the reflow temperature, the Al melts and causes flow due to surface tension, so that the bottom surface bridges and the opening 4 can be sealed as shown in FIGS. is there.

  In sealing the opening 4, it is not always necessary to form a TiN film or a Ti film. That is, the opening 4 can be sealed even if either or both of the TiN film and the Ti film are absent.

  Further, when the opening 4 is sealed, if the side cross-sectional shape of the opening 4 is formed in a tapered shape that becomes narrower toward the hollow structure portion 2, the sealing becomes even easier and more reliable. It becomes. If the side cross-sectional shape of the opening 4 is formed in a tapered shape, even if there is a residue at the time of forming the opening on the tapered inclined surface, the residue is smaller than when the side wall portion of the opening is a vertical surface. This is because the film forming material for the sealing film 6 can be easily deposited. In other words, the presence of the tapered inclined surface makes it possible to avoid the generation of voids when sealing the opening 4, thereby further reliably sealing the opening 4.

  The opening 4 thus sealed has a sealable size (for example, a diameter) of about 0.5 to 4 μm, but the bottom of the sealing film 6 bridges if the size is about 1.2 μm. Thus, the bottom surface of the sealing film 6 does not contact the gap base film. The bridge is caused by the surface tension F of Al, which is the film forming material of the reflowed sealing film 6. However, the surface tension F is proportional to the circumference πD of the diameter D of the opening 4, and the mass W of Al reflowed in the opening 4 is W = ρπD2t / 2 (ρ is the specific gravity of Al, t is the depth of the opening 4) ). Therefore, it is considered that a bridge is formed when F> W. FIG. 5 is an explanatory diagram showing the concept of whether or not a bridge is generated. Note that the presence / absence of the occurrence of the bridge is not only affected by the relationship between the surface tension F and the mass W, but also by the presence / absence of the adhesion layer, the adhesion with the sacrificial layer base film, the angle of the tapered inclined surface, and the like. However, since the positive sealing of the opening 4 is not affected, the description thereof is omitted here.

  By the way, since the film thickness of the sealing film 6 inevitably increases with opening sealing, portions other than the opening sealing portion may be removed by patterning as shown in FIG. Absent. However, in that case, it is also conceivable that the interface with the base layer is exposed by the removal of the sealing film 6, and the outside air enters the gap of the hollow structure portion 2 through the interface. Therefore, when the sealing film 6 is removed by patterning, the thinnest possible film (for example, an insulating film formed on the etching resistant layer prior to the formation of the sealing film 6) is exposed on the entire surface. It is desirable to leave or overcoat the cover layer 7 after forming the sealing film 6 by etching. In the former (in the case of leaving the film), even if there is a difference in the thickness of the sealed film, the entire surface is covered and no interface is generated. However, the remaining film is preferably an insulating film. On the other hand, the latter (in the case of overcoating) leaves the sealing film 6 only in the vicinity of the opening by patterning, and the sealing film 6 is removed at other locations to form an interface. Is. The cover layer 7 at this time is composed of at least one CVD film, but is preferably an insulating film having a thickness of 100 nm or more.

  As described above, when the opening 4 is sealed according to the procedure described in this embodiment, the sealing film 6 that seals the opening 4 has a temperature higher than the reflow temperature of the film forming material of the sealing film 6. Since the film is formed at the film temperature or the annealing temperature after the film formation, the film forming material of the sealing film 6 melts and flows due to the surface tension. Therefore, even when the opening 4 is sealed by forming the sealing film 6, it becomes easy to fill the opening 4 with the film forming material of the sealing film 6, and the opening 4 is sealed. The generation of voids can be avoided. That is, even when the opening 4 is sealed after the sacrificial layer is removed to form the hollow structure portion 2, the sacrificial layer is not subject to special restrictions on the film thickness, film forming material, etc. Since the opening 4 can be reliably sealed, the function realization by the hollow structure portion 2 can be ensured.

  Moreover, as described in the present embodiment, prior to the Al sputtering for forming the sealing film 6, the sacrificial layer is formed at a film formation temperature when performing the Al sputtering or a temperature equal to or higher than the annealing temperature after the Al sputtering. If the pre-heat treatment is performed to heat the space after the removal of moisture, moisture, impurities, and the like that may cause voids are removed from the space after the sacrificial layer is removed. The opening 4 can be reliably sealed while avoiding the generation of voids. This is very suitable for ensuring the certainty of sealing when sealing for forming the hollow structure portion 2 which is an airtight space, not simply sealing the opening. It becomes. Pre-heating is also necessary for embedding vias with reflow aluminum in the semiconductor manufacturing process, but temperature and time management are important for sealing a hollow structure because the surface area inside the hollow is extremely large compared to the via. Yes, it simply takes longer than the substrate temperature stabilization time (generally 30 seconds) before the electrostatic chuck.

  Furthermore, as described in the present embodiment, if a cover layer 7 that is at least one CVD film is laminated on the sealing film 6, even if a portion other than the opening sealing portion is removed by patterning, By removing the sealing film 6, it is possible to reliably prevent the interface with the base layer from being exposed and the outside air from entering the gap of the hollow structure portion 2 through the interface. Moreover, since this can be realized by forming a CVD film, the versatility of the process can be sufficiently secured, and the process does not require any special difficulty. In addition, it can be expected to prevent aluminum from entering the crystal grain boundary, complement aluminum sealing defects, and prevent aluminum corrosion.

  For these reasons, the functional element 1 manufactured by the procedure described in the present embodiment can be surely sealed in the opening 4 without forming a void, so that the airtightness in the hollow structure portion 2 is greatly increased. The long-term reliability as a device having the hollow structure portion 2 is greatly improved. For example, it is possible to realize a vacuum-sealed vibrator or the like. In that case, damping due to air resistance can be prevented and a high Q value can be secured. In general, a large number of openings 4 for removing the sacrificial layer are required at a narrow pitch, whereas the internal pressure and gas type of the hollow structure portion 2 can be controlled by one small hole. It is also possible to form one or a small number of holes again after forming the airtight space, and perform sealing again by controlling the environment in the hollow structure portion 2 from the holes.

  In addition, the functional element 1 manufactured by the procedure described in this embodiment can be hermetically sealed in a wafer level process, and accordingly, the cost of the device can be reduced. For example, when packaging or bonding with metal, ceramic, glass, resin, etc. is used to achieve hermetic sealing, processes such as welding, soldering, and anodic bonding of two or more materials are required. A frame-shaped joining margin is required, and the chip area increases. Although this may cause an increase in cost and a decrease in yield, as described above, if airtight sealing is performed in the wafer level process, the material and process can be simplified, resulting in a significant cost reduction. It becomes possible.

  Further, in the functional element 1 manufactured by the procedure described in this embodiment, since the film forming material of the sealing film 6 melts and flows due to surface tension, the surface of the sealing film 6 is flat after sealing. (See, for example, FIG. 4E). Therefore, the sealing inspection by the sealing film 6 is greatly facilitated. Just by performing Al sputtering as in the past, the surface after sealing becomes a mortar shape, so it was difficult to observe the bottom of the hole and it was difficult to confirm the location where the defect occurred. This is because if the surface is flattened and there is no void, visual confirmation is possible. Thereby, in the functional element 1 in the present embodiment, it is possible to reduce the market defects and facilitate the analysis.

  Further, in the functional element 1 manufactured by the procedure described in the present embodiment, since the film forming material of the sealing film 6 melts and causes flow due to surface tension, the bottom surface of the sealing film 6 causes a bridge and below the gap. No contact with the ground film (see, for example, FIG. 4E). This means that the presence or absence of contact with the gap base film can be properly used depending on the process. That is, depending on whether or not the low-temperature sputtering process is put before the high-temperature sputtering process, it is possible to selectively use the presence or absence of contact with the gap base film, and to ensure high versatility of the process. Furthermore, it is effective when the device must be arranged directly under the opening 4 and when it is not desired to leave the sealing film 6 in the device as much as possible. is there. Further, when the film thickness of the low-temperature sputtering is thinner than that of the high-temperature film, even when the sputtering temperature is sufficiently high, the low-temperature sputtering film melts and the same phenomenon as that of only the high temperature occurs.

  For these reasons, the functional element 1 described in the present embodiment is very suitable when applied to a fluid ejection head in an electrostatic MEMS inkjet printing apparatus. This is because the establishment of a hermetic sealing technique enables a structure based on the so-called surface MEMS technology method, achieving high density and preventing ink from entering the hollow structure portion 2. Because. This means that the micropump by the surface MEMS process can be put into practical use. This enables an ultra-compact cooling system for high heat generation LSI (Large Scale Integration) such as a CPU (Central Processing Unit), which eliminates the need for air-cooling arrangements and enables downsizing of computer devices. In addition, it becomes quieter because an air cooling fan is unnecessary. Further, in LSIs that have been miniaturized in recent years, Low-K (low dielectric constant) materials are required, and ultimately it is effective to perform three-dimensional wiring in a vacuum. In contrast, the functional element 1 described in the present embodiment is suitable for sealing a hollow structure in which the interlayer film is removed and only the wiring or gate material is left in the hollow structure portion 2. It is also very suitable for realizing high density, miniaturization, high speed, low power consumption, etc. of LSI wiring.

[Description of fluid ejection head and printing apparatus]
Next, a fluid ejection head and a printing apparatus configured using the functional element 1 as described above will be described.

  First, the printing apparatus will be described. As an example of the printing apparatus, an ink jet printer apparatus is known. FIG. 6 is an explanatory diagram showing an outline of the inkjet printer apparatus. The ink jet printer device prints and outputs a photo-quality printed matter at a high speed by discharging ink onto a sheet in a fine granular form. Such an ink jet printer apparatus is roughly classified into a serial head type and a line head type.

  In the case of the serial head type, as shown in FIG. 6A, a paper 22 as a printing object is mounted on a roller 22 that feeds in the main scanning direction, and a carriage 23 that can move in the sub-scanning direction of the paper 21. The inkjet head 24 is provided. The inkjet head 24 ejects ink onto the paper 21 while moving the paper 21 and the carriage 23, thereby performing print output. On the other hand, in the case of the serial head type, as shown in FIG. 6B, the roller 22 for feeding the paper 21 in the main scanning direction and the ink discharge ports in a line shape along the sub-scanning direction of the paper 21 The inkjet head 25 is provided. Then, printing is performed by ejecting ink from each ejection port of the inkjet head 25 onto the paper 21 while moving the paper 21.

  However, in any system, in order to meet the need to print higher image quality at high speed for inkjet printers, the number of pixels can be increased without increasing the power consumption and without reducing the ejection performance. Realization of higher density is demanded. In order to meet such a demand, some inkjet printer apparatuses are configured using inkjet heads 24 and 25 based on electrostatic MEMS. In the electrostatic MEMS system, the inkjet heads 24 and 25 are configured using the functional elements as described above, and the vibration of the functional elements is used as pressure application means, so that the ink on the paper 21 can be applied. The discharge is performed. It should be noted that constituent elements other than the ink jet heads 24 and 25 in the ink jet printer apparatus may be realized by a publicly known technique, and the description thereof is omitted here.

  Next, an ink jet head used in an ink jet printer apparatus, that is, an ink jet head which is an example of a fluid discharge head configured using the functional elements described above will be described. However, here, only the main part of the inkjet head configured using the functional elements described above will be described regardless of whether the serial head method or the line head method is used. 7 to 9 are schematic views showing an example of the configuration of the main part of the ink jet head according to the present invention. FIG. 7 is a perspective view thereof, FIG. 8 is a plan view thereof, and FIG.

  As shown in FIG. 7, the inkjet head described here includes a microfluidic drive unit 30 and a fluid supply unit 40. The microfluidic drive unit 30 is formed by arranging a plurality of diaphragms 31 driven (vibrated) by electrostatic force in parallel at high density. On the other hand, the fluid supply unit 40 is disposed at a corresponding position on each diaphragm 31 and serves as a pressure chamber (so-called cavity) 42 in which ink 41 as fluid is stored, and an outer wall for forming the pressure chamber 42. The partition structure 43 and a discharge portion (so-called nozzle) 44 for discharging the ink 41 in the pressure chamber 42 to the outside are provided.

  8 and 9, the microfluidic drive unit 30 has a common substrate side electrode 33 made of a conductive material thin film formed on a substrate 32, and an insulating film on the surface of the substrate side electrode 33. A plurality of diaphragm-side electrodes 35 and diaphragms 31 that are independently driven with a hollow structure space (hereinafter referred to as “hollow structure portion”) 34 interposed therebetween so as to face the substrate-side electrode 33 are integrally formed. In addition, the support column 36 is formed on the substrate 32 so as to be arranged in parallel and further to support each diaphragm 31 with a doubly supported beam.

  Of these, the substrate 32 may be, for example, a substrate in which an insulating film 32b made of a silicon oxide film or the like is formed on a silicon substrate 32a. It is also possible to use an insulating material such as a glass substrate including a quartz substrate or a glass substrate including a quartz substrate.

  The substrate side electrode 33 may be formed of, for example, a polycrystalline silicon film doped with impurities, but may be a metal film (for example, a deposited film of Pt, Ti, Al, Au, Cr, Ni, Cu, etc.) or ITO (Indium). (Tin Oxide) film or the like may be used. Similarly, the diaphragm side electrode 35 may be formed of an impurity-doped polycrystalline silicon film, a metal film, an ITO film, or the like.

  The diaphragm 31 is formed of an insulating film, but is preferably formed of a silicon nitride film (SiN film) that can obtain a particularly high repulsive force. However, the diaphragm 31 is formed by laminating these respective films, with silicon oxide films formed on the upper and lower surfaces of the SiN film. The diaphragm 31 is formed in, for example, a strip shape, and is supported by a plurality of support columns 36 formed on the both sides thereof at predetermined intervals (pitch between support columns) along the longitudinal direction. The predetermined interval is preferably 2 μm or more and 10 μm or less, and most preferably about 5 μm. The adjacent diaphragms 31 arranged in parallel are continuously formed through the support pillars 36, and the support pillars 36 are also integrally formed of the same material as the diaphragm 31. Therefore, the hollow structure portion 35 constituting the space between the diaphragm 31 and the substrate side electrode 33 is communicated between the plurality of diaphragms 31 arranged in parallel, and is formed to be a sealed space. It will be a thing.

  Further, when performing sacrificial layer etching for forming the hollow structure portion 35 in the vicinity of the struts 36 of each diaphragm 31, specifically, for example, between the struts 36 along the longitudinal direction of one diaphragm 31. An opening 37 to be used is formed. The opening 37 is closed by the sealing film 38 after the sacrifice layer etching. Since the smaller the size of the opening 37 is, the smaller the opening 37 is, the more likely it is to close, □ 2 μm or less may be considered. However, if sacrificial layer etching is dry etching, □ 0.5 μm is sufficient.

  A diaphragm side electrode 35 is bonded to the diaphragm 31 via an insulating film, and the diaphragm side electrode 35 is arranged so as to be inserted into the bent lower surface recess of the diaphragm 31. It shall be installed. Further, below the diaphragm 31, in order to increase the repulsive force when the diaphragm 31 is thinly formed, an auxiliary strut (so-called post) 39 is provided in the vicinity of the center portion together with the strut (so-called anchor) 36. May be formed (see, for example, FIG. 7).

  With respect to such a microfluidic drive unit 30, a fluid supply unit 40 is disposed so that a partition wall 43a in the partition wall structure 43 is formed at a position corresponding to the support column 36 of the diaphragm 31, and an ink jet head is configured. It is. Note that a fluid supply path (not shown) communicates with the pressure chamber 42 of the fluid supply unit 40 disposed on the microfluidic drive unit 30 in order to supply the ink 41 into the pressure chamber 42. It shall be.

  Here, the processing operation in the ink jet head having the above configuration will be described. In the inkjet head, when a required voltage is applied between the substrate side electrode 33 and the diaphragm side electrode 35 in the microfluidic drive unit 30, an electrostatic attractive force is generated between the electrodes as shown in FIG. Thus, the diaphragm 31 integrated with the diaphragm side electrode 35 is bent toward the substrate side electrode 33. On the other hand, when the voltage application between the substrate side electrode 33 and the diaphragm side electrode 35 is released, the diaphragm 31 is released from electrostatic attraction as shown in FIG. Damping vibration. Due to the volume fluctuation of the pressure chamber 42 in the fluid supply unit 40 due to the vertical vibration of the diaphragm 31, the ink 41 in the pressure chamber 42 is ejected from the nozzle 44 to the outside and the fluid is supplied into the pressure chamber 42. The ink 41 is supplied through the path.

  At this time, when the vibration plate 31 bends toward the substrate side electrode 33, the hollow structure portion 35 is a closed space, so that the air in the hollow structure portion 35 is compressed and attempts to inhibit the deformation of the vibration plate 31. To do. However, if the vibration plate 31 is a support structure by the support column 36, the auxiliary support column 39, etc., the compressed air can be released into the hollow structure portion 35 below the adjacent vibration plate 31, resulting in sufficient vibration plate. 31 can be bent.

  Next, a method for manufacturing the ink jet head having the above configuration will be described. 11 to 13 are explanatory views showing an outline of a method of manufacturing an ink jet head.

  In manufacturing the ink jet head, particularly in manufacturing the microfluidic drive unit 30 and the fluid supply unit 40, first, as shown in FIG. 11A, a substrate 51 is prepared. As already described, the substrate 51 may be a substrate in which an insulating film 51b made of a silicon oxide film or the like is formed on a silicon substrate 51a, for example.

Then, as shown in FIG. 11B, for example, an impurity-doped polysilicon film 52 to be the substrate-side electrode 33 is selectively formed on the substrate 51, and an insulating film 53 is further formed on the surface thereof. The insulating film 53 is a protective film for the substrate-side electrode 33 and is formed of a film that is resistant to sacrificial layer etching described later. Specifically, for example, when the sacrificial layer etching uses an etching gas such as SF ₆ , CF ₄ , or XeF _2, it is formed of a silicon oxide film, and when an etching gas of hydrofluoric acid is used, it is formed of a silicon nitride film. Good.

  After that, as shown in FIG. 11C, the sacrificial layer 54 is selectively formed in the region where the microfluidic drive unit 30 by the electrostatic MEMS element is to be formed, except for the support portion by the support column 36, the auxiliary support column 39, and the like. Form. The film type of the sacrificial layer 54 is determined by the etchant. As described above, the interval between the support columns 36 is preferably 2 μm or more and 10 μm or less, and most preferably about 5 μm.

  Then, as shown in FIGS. 11D to 11F, on the sacrificial layer 54, for example, a silicon oxide film 55 that is an insulating film, and a diaphragm-side electrode 35 having a film thickness of, for example, about 300 nm. A polysilicon film 56, a silicon oxide film 57 having a film thickness of about 70 nm, which is an insulating film, a silicon nitride film 58 having a film thickness of about 300 nm by, for example, low pressure CVD (film formation temperature is 700 ° C. to 900 ° C.) having a tensile stress, and A silicon oxide film 59 having a thickness of about 70 nm, for example, formed by CVD, which becomes an insulating protective film, is sequentially formed and laminated. The silicon oxide film 59 can be omitted. It is also conceivable that the polysilicon film 56 is subjected to ion implantation of a predetermined impurity after the film formation and annealed to lower its resistance value and then patterned. Further, phosphorus-doped amorphous silicon may be used in place of the polysilicon film 56, and it is also conceivable to form a silicon nitride film 58 and a silicon oxide film 59 thereafter.

The laminated film in which the films 55 to 59 are laminated in this manner is then selectively so that the portion corresponding to the side wall of the fluid supply path is exposed (opened) as shown in FIGS. The opening 61 is formed by patterning. The opening 61 is for selectively removing the sacrificial layer 54 by sacrificial layer etching. In forming the opening 61, the side cross-sectional shape may be formed in a tapered shape that becomes narrower toward the hollow structure portion 2. When forming the tapered inclined surface, first, isotropic etching is performed as shown in FIG. At this time, since the angle of the mouth of the opening 61 is determined, the isotropic etching is performed shallowly. Then, as shown in FIG. 12B, the opening 61 is dug down by RIE using a gas such as CF ₄ or C ₄ F ₈ . Thereby, the opening 61 has a tapered inclined surface of approximately 45 °. Thereafter, the opening 61 is further dug down until the sacrificial layer 54 having a thickness of about 100 nm, which is a gap height that can seal the opening 61 and does not hinder sacrificial layer etching, remains. Over-etching is performed on the sacrificial layer 54.

  After the opening 61 is formed in this way, then, as shown in FIG. 12C, a silicon oxide film 62 as a sidewall protective layer of the opening 61 is formed by CVD with a film thickness of about 100 nm. Then, as shown in FIG. 12D, a tapered inclined surface is used by using again the exposure mask used when patterning the opening 61 or using an exposure mask different from the exposure mask. A hole 63 having a diameter of about 0.5 μm is formed by patterning on the bottom of the opening 61 formed in a mortar shape. The hole 63 can be filled with about φ10 μm, but it is desirable that the hole 63 is about φ0.5 μm in consideration of the interval between the columns 36 and the like.

  In each step shown in FIGS. 12A to 12D, it is conceivable that a contact hole with an electrode for connection to the outside is formed at the same time as the opening 61 is formed. Then, in order to form an electrode for connection to the outside, metal sputtering and patterning are performed. At this time, Al is optimal for metal sputtering.

After that, as shown in FIG. 12E, sacrificial layer etching is performed using the opening 61 and the hole 63 formed in the opening 61 to selectively remove the sacrificial layer 54. When the sacrificial layer 54 is made of a polysilicon film, a gas such as XeF ₂ , SF ₆ , or CF ₄ may be used for the etchant. When the insulating films 53 and 55 are made of a silicon nitride film and the sacrificial layer 54 is made of a silicon oxide film, a hydrofluoric acid solution may be used as an etchant. By removing the sacrificial layer 54, the microfluidic drive unit 30 having an electrostatic MEMS structure including the substrate side electrode 33, the hollow structure portion 35, the diaphragm side electrode 35, and the diaphragm 31 is formed. It is.

  However, the opening 61 and the hole 63 are not sealed only by performing the sacrifice layer etching. Therefore, after the sacrificial layer etching, as shown in FIG. 13A, the opening 61 and the hole 63 that are still open are sealed. This sealing is performed by metal sputtering, and Al sputtering is particularly suitable. Note that a film thickness of 1 μm or less is sufficient at this time.

  Here, the sealing of the opening 61 and the hole 63 will be described in detail. In the case of sealing the opening 61 and the hole 63, the sacrificial layer 54 was first removed prior to the Al sputtering at a film formation temperature at the time of the Al sputtering or an annealing temperature after the Al sputtering. Pre-heating treatment is performed to heat the subsequent space. By such preheating treatment, moisture, impurities, and the like that may cause voids are removed from the hollow structure portion 35 after the sacrificial layer 54 is removed.

  After the pre-heating treatment, an Al sputtering is performed on the upper surface of the silicon oxide film 62 by forming a TiN film for preventing Al diffusion and a Ti film as an Al adhesion layer as necessary. Then, an Al film is formed. At this time, Al sputtering is performed at a film formation temperature equal to or higher than a reflow temperature of Al as a film formation material. For example, the Al film is sputtered at a low temperature of, for example, about 500 nm, and then the Al film is sputtered at a temperature equal to or higher than the reflow temperature, for example, at a thickness of about 500 nm. Further, it is not always necessary to form the film in two steps. For example, an Al film having a thickness of about 1 μm may be sputtered at a temperature higher than the reflow temperature. Furthermore, an Al film having a thickness of about 1 μm may be sputtered at a low temperature, and annealing may be performed at a temperature higher than the Al reflow temperature after the film formation.

  When an Al film is formed at a temperature equal to or higher than the reflow temperature or an annealing process after the film is formed, Al, which is a film forming material of the Al film, melts and flows due to surface tension. Therefore, even when the opening 61 and the hole 63 are sealed, unlike the case of sealing by simple Al sputtering, Al filling becomes easy and an Al film without voids can be formed. Therefore, the 63 can be surely sealed.

  In this way, after the Al sputtering is performed and the opening 61 and the hole 63 are sealed, patterning is performed on the Al film as a film formation result by the Al sputtering, and the Al film is left only in the opening 61 portion. Remove. As a result, the sealing film 64 is formed in the portion of the opening 61.

  Thereafter, in order to prevent intrusion of outside air, fluid, and the like from the interface between the sealing film 64 and the silicon oxide film of the outermost layer of the microfluidic drive unit 30, as shown in FIG. A plasma silicon nitride film 65 to be formed is laminated with a film thickness of, for example, 30 nm or more by CVD. The cover layer may be a plasma oxide film.

  After the microfluidic drive unit 30 is configured in this way, thereafter, as shown in FIG. 13C, a thick film negative resist 66 that forms the partition wall 43a constituting the fluid supply unit 40 is formed to a height of 50 μm or more. Further, as shown in FIG. 13 (d), a nozzle sheet 67 having nozzles 67a is adhered thereon. As a result, the fluid supply unit 40 is formed on the microfluidic drive unit 30, and as a result, an ink jet head including the microfluidic drive unit 30 and the fluid supply unit 40 is configured. The partition wall 43a may be formed by, for example, patterning glass by etching or sand blasting and bonding. Moreover, it is also possible to form the partition wall 43a and the nozzle sheet 67 by integral molding, for example with resin.

  According to the ink jet head configured as described above and the ink jet printer apparatus using the ink jet head, the functional element having the hollow structure portion 35, that is, the functional element that vibrates the diaphragm 31 by electrostatic attraction is used. Therefore, the ink 41 that is a micro fluid can be accurately controlled and ejected. Furthermore, since it is formed by the thin film formation technique as described above, it is very easy to cope with high density while ensuring the driving force for the ink 41. Therefore, it is possible to increase the number of pixels without increasing power consumption and without reducing ejection performance, so that it can sufficiently meet the need for high-quality printing at high speed. Become.

  Moreover, in the above-described ink jet head and ink jet printer apparatus, the sealing film 64 is Al sputtered at a film forming temperature equal to or higher than the Al reflow temperature or annealed at an annealing temperature equal to or higher than the Al reflow temperature. The openings 37 and 61 can be reliably sealed while avoiding the generation of voids. Furthermore, since the pre-heating treatment is performed prior to the Al sputtering, it becomes even more suitable for ensuring the sealing of the openings 37 and 61. Even when applied to an ink jet head that handles ink 41, which is a microfluidic, these things ensure that the ink 41 penetrates into a location where the ink 41 should not enter, particularly in the hollow structure portion 35. Since it can be prevented, it becomes very effective.

In the present embodiment, an ink jet head has been described as an example of a representative fluid ejection head, but the present invention is not limited to this. As fluid ejection heads, in addition to inkjet heads, for example, polymer or low molecular organic material coating devices such as organic EL, printed circuit board wiring printing devices, solder bump printing devices, three-dimensional modeling devices, μTAS (Micro Total Analysis Systems) Examples include supply heads that control and supply chemical liquids and other liquids in minute units of pl (picoliters) or less, and supply heads that control and supply gases in minute amounts with high precision. It is possible to apply the present invention in exactly the same way.
The same applies to the printing apparatus. That is, the printing apparatus according to the present invention is not limited to the ink jet printer apparatus as long as it uses a fluid ejection head.
Further, the same applies to the functional elements constituting the fluid ejection head, and the present invention can be applied to any functional element having a hollow structure. Examples of such functional elements include fluid ejection devices such as inkjet heads, micropumps, hot spots such as LSIs that eject gas or liquid refrigerant, and cooling / heat diffusion devices that cool the entire chip, μTAS (Micro Total Analysis Systems), DNA chips, and other MEMS that can be used as frequency filters, various sensors, optical switches, switches including relays, and the like. In addition to these, a semiconductor element, a resonator, a vibrator, an FBAR (Film Bulk Acoustic Resonator), a SAW (surface acoustic wave) filter, an acceleration sensor, a gyro sensor, a liquid crystal, or the like, as long as it has a hollow structure portion. Element, organic electroluminescence element, resistance element, relay element, LED (Light Emitting Diode), laser element, light source element such as FED (Field Emission Display), speaker element, diaphragm type sensor (for example, microphone, pressure sensor), flow There are roads, tubes, image sensors, etc., and the present invention can be easily applied to any of these, and in that case, it contributes to miniaturization, cost reduction, high performance, etc. . In addition, for these functional elements, there are a hollow structure part that is completely sealed and a part that is partially open, but the present invention can be applied to any of these functional elements. is there.

  In the present embodiment, the case where the hollow structure portion 34 is formed by sacrificial layer etching has been described as an example. However, the hollow structure portion 34 is not necessarily limited to that formed by sacrificial layer etching. Absent. That is, here, the case where the openings 37 and 61 are sealed to form the hollow structure portion 34 for operating the diaphragm 31 has been described as an example. It is also conceivable to apply this method when forming the film. For example, as shown in FIG. 14A, even when the substrate or a layer stacked on the substrate is etched to form the fluid supply path 71, the fluid supply path 71 is sealed with a sealing film 72. As in the case of the hollow structure portion 35 described above, if the film is formed at a temperature equal to or higher than the reflow temperature of the film forming material of the sealing film 72, the sealing can be surely performed. Thus, the supply of the ink 41 to the fluid supply unit 40 can be ensured. In addition, when comprised in this way, it is suitable for formation of the thin fluid supply path 71. FIG. Further, for example, as shown in FIG. 14B, after the substrate or a layer laminated on the substrate is etched from the back surface of the substrate to form the fluid supply channel 71, the fluid supply channel 71 is replaced with a sealing film 72. The same applies to the case of sealing. With such a configuration, it is possible to prevent a trouble that the sealing film 72 is damaged and the fluid supply path 71 is opened. For example, as shown in FIG. 14C, after forming the sealing film 72, the film supply material is reflowed by annealing at a temperature equal to or higher than the reflow temperature of the film formation material, and the fluid supply path 71. It is also possible to cover.

  Thus, it goes without saying that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.

It is explanatory drawing which shows an example of schematic structure of the functional element which concerns on this invention. It is explanatory drawing (the 1) which shows the outline | summary of the manufacturing method of the functional element which concerns on this invention. It is explanatory drawing which shows the outline | summary of the prior art example used as the comparison object with the functional element which concerns on this invention. It is explanatory drawing (the 2) which shows the outline | summary of the manufacturing method of the functional element which concerns on this invention. It is explanatory drawing which shows the concept of the presence or absence of bridge | bridging generation | occurrence | production. It is explanatory drawing which shows the outline | summary of an inkjet printer apparatus. It is a perspective view showing typically an example of the principal part composition of the ink-jet head concerning the present invention. It is a top view showing typically an example of the important section composition of the ink-jet head concerning the present invention. It is a sectional side view showing typically an example of the important section composition of the ink-jet head concerning the present invention. It is explanatory drawing which shows typically the outline | summary of the processing operation in the inkjet head which concerns on this invention. It is explanatory drawing (the 1) which shows the outline | summary of the manufacturing method of the inkjet head which concerns on this invention. It is explanatory drawing (the 2) which shows the outline | summary of the manufacturing method of the inkjet head which concerns on this invention. It is explanatory drawing (the 3) which shows the outline | summary of the manufacturing method of the inkjet head which concerns on this invention. It is explanatory drawing which shows the other example of schematic structure of the functional element which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Functional element, 2 ... Hollow structure part, 3 ... Vibrator, 4 ... Opening, 5 ... Etching-resistant layer, 6 ... Sealing film, 7 ... Cover layer, 8 ... Over-etching part, 21 ... Paper, 22 ... Roller , 23 ... Carriage, 24, 25 ... Inkjet head, 30 ... Microfluidic drive unit, 31 ... Diaphragm, 32 ... Substrate, 33 Substrate side electrode, 34 ... Hollow structure part, 35 ... Diaphragm side electrode, 36 ... Post, 37 ... Opening, 38 ... Sealing film, 39 ... Auxiliary strut (post), 40 ... Fluid supply part, 41 ... Ink, 42 ... Pressure chamber (cavity), 43 ... Partition structure, 43a ... Partition, 44 ... Discharge part ( Nozzle), 51 ... Substrate, 52 ... Polysilicon film, 53 ... Insulating film, 54 ... Sacrificial layer, 55 ... Silicon oxide film, 56 ... Polysilicon film, 57 ... Silicon oxide film, 58 ... Silicon nitride film, 59 ... Silicon Oxide film, 61 ... open 62 ... Silicon oxide film, 63 ... Hole, 64 ... Sealing film, 65 ... Plasma silicon nitride film, 66 ... Thick film negative resist, 67 ... Nozzle sheet, 67a ... Nozzle, 71 ... Fluid supply path, 72 ... Sealing film

Claims (16)

The opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure part,
The sealing film is formed by raising a film forming temperature in the physical vapor deposition or an annealing temperature after the film formation to a temperature higher than a reflow temperature of a film forming material of the sealing film. Functional element. Prior to the physical vapor deposition, the hollow structure portion has been subjected to a preheating treatment at a temperature equal to or higher than the film formation temperature or the annealing temperature for a time during which degassing of the inner surface of the hollow structure portion is possible. The functional element according to claim 1. The functional element according to claim 2, wherein at least one film is laminated on the sealing film. The functional element according to claim 1, wherein the physical vapor deposition is metal sputtering. Forming an opening;
Forming a sealing film for sealing the opening by physical vapor deposition;
A functional element characterized in that a hollow structure portion is formed by a step of raising a film forming temperature during physical vapor deposition or an annealing temperature after film forming to a temperature higher than a reflow temperature of a film forming material of the sealing film. Manufacturing method. Prior to the physical vapor deposition, including a step of performing a preheating treatment on the hollow structure portion at a temperature equal to or higher than the film formation temperature or the annealing temperature for a time period capable of degassing the inner surface of the hollow structure portion. A method for manufacturing a functional element according to claim 5. The method for producing a functional element according to claim 6, further comprising: laminating at least one film on the sealing film. The method of manufacturing a functional element according to claim 5, wherein the physical vapor deposition is metal sputtering. The opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure part,
The sealing film is formed by raising a film forming temperature in the physical vapor deposition or an annealing temperature after the film formation to a temperature higher than a reflow temperature of a film forming material of the sealing film. Fluid discharge head. Prior to the physical vapor deposition, the hollow structure portion has been subjected to a preheating treatment at a temperature equal to or higher than the film formation temperature or the annealing temperature for a time during which degassing of the inner surface of the hollow structure portion is possible. The fluid discharge head according to claim 9. The fluid ejection head according to claim 10, wherein at least one film is laminated on the sealing film. The fluid ejection head according to claim 9, wherein the physical vapor deposition is metal sputtering. The opening is sealed with a sealing film formed by physical vapor deposition to form a hollow structure part,
The sealing film is formed by raising a film forming temperature in the physical vapor deposition or an annealing temperature after the film formation to a temperature higher than a reflow temperature of a film forming material of the sealing film. Printing device. Prior to the physical vapor deposition, the hollow structure portion has been subjected to a preheating treatment at a temperature equal to or higher than the film formation temperature or the annealing temperature for a time during which degassing of the inner surface of the hollow structure portion is possible. The printing apparatus according to claim 13, wherein The printing apparatus according to claim 14, wherein at least one film is laminated on the sealing film. The printing apparatus according to claim 13, wherein the physical vapor deposition is metal sputtering.

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