JP2006056001A - Functional element, its manufacturing method, fluid ejecting apparatus, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional element which can suppress a shape variation at the time of wall formation to small so that a stable fluid jetting characteristic can be obtained surely. <P>SOLUTION: The functional element is equipped with an opening 18 for forming a hollow structural part 15, a sealing film 19 which seals the opening 18, and a wall 23 formed on the sealing film 12. The sealing film 19 has a top face part 19a and a side wall part 19b with an inclination. The wall 23 is formed so that a width between both side faces of the wall 23 becomes narrower than a formation width of the top face part 19a or becomes wider by a predetermined value or more than a maximum formation width of the sealing film 19 including the top face part 19a and the side wall part 19b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a functional element having a hollow structure portion, a manufacturing method thereof, and a fluid ejection apparatus and a printing apparatus configured using the functional element.

  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.

  Here, as a specific example in which a functional element having a hollow structure portion is used, an ink jet head (fluid ejection device) constituting a printing apparatus such as a printer or a facsimile is taken as an example, and the configuration will be briefly described. The inkjet head includes a nozzle that discharges ink liquid, a flow path of ink liquid that communicates with the nozzle, and an actuator that pressurizes the ink liquid in the flow path, and pressurizes the ink liquid by driving the actuator. In this way, ink is ejected from the nozzles. Conventionally, it has been proposed to use a functional element having a hollow structure portion as an actuator constituting the ink jet head (see, for example, Patent Document 1). Specifically, for example, as shown in FIG. 11, a part of the flow path of the ink liquid is formed by a vibration plate 52 that can be deformed by the presence of the hollow structure portion 51, and the individual electrode 53 is opposed to the vibration plate 52. The nozzle 52 is disposed by changing the pressure and volume in the liquid chamber 54 by generating an electrostatic force by applying an electric field between the diaphragm 52 and the individual electrode 53 to deform the diaphragm 52. The ink liquid is ejected from 55.

  In such a functional element, the hollow structure portion 51 required for the vibration plate 52 to be deformed (vibrated) is generally formed by performing so-called sacrificial layer etching. For this purpose, an opening 56 for etching the sacrificial layer is required. When an ink liquid (liquid) is handled like an inkjet head, the opening 56 is used to prevent the liquid from flowing into the hollow structure portion 51. 56 is sealed by a sealing film 57. The sealing film 57 is patterned so that the formation range remains in the vicinity of the opening 56 so as not to affect the vibration characteristics of the diaphragm 52. Further, the flow path wall (wall body) 58 constituting the side wall of the liquid chamber 54 located above the vibration plate 52 is also formed on the sealing film 57 so as not to affect the vibration characteristics of the vibration plate 52. Overlaid.

Japanese Patent No. 2854876

  By the way, in the fluid ejection device that ejects a small amount of fluid like the above-described ink jet head, in order to obtain stable fluid ejection characteristics, the resistance value in the liquid chamber 54 in which pressurization to the ejection fluid such as ink liquid is performed. It is very important to stabilize the above, that is, to suppress the variation in the shape of the wall body 58 constituting the flow path of the discharged fluid.

  Therefore, in forming the wall body 58, even if it is formed by a thin film formation technique, the wall body 58 is not formed by etching a base material such as silicon by etching, but the wall body 58 is made of a photosensitive material, for example, It can be considered that the etching step is not required by forming the photosensitive resin or the photosensitive glass, and the variation in the etching width and the etching depth is excluded, thereby eliminating the variation in the channel resistance value due to this parameter.

  However, the sealing film 57 positioned below the wall body 58 is patterned using, for example, a known lithography technique. For example, as shown in FIG. 12, the side wall formed by the patterning has an inclination θ. It is conceivable that the cross-sectional shape is formed in a trapezoidal shape extending downward from the upper surface portion. It is also conceivable that the cross-sectional shape is formed in a trapezoidal shape that narrows downward from the upper surface. That is, the sealing film 57 is formed in a trapezoidal cross section having an upper surface portion and a side wall portion having an inclination θ.

  Therefore, when the wall body 58 is made of a photosensitive material, for example, as shown in FIG. 13, the light that has passed through the exposure mask 59 when the photosensitive material is exposed passes through the side wall portion of the sealing film 57. There is a risk of causing irregular reflection. Such irregular reflection of the exposure light affects the formation of the wall body 58, and as a result, the shape of the wall body 58 varies greatly, which makes it difficult to obtain stable fluid ejection characteristics.

  Accordingly, the present invention provides a functional element capable of suppressing a variation in shape when forming a wall body, a manufacturing method thereof, a fluid ejection device, and a printing device in order to ensure stable fluid ejection characteristics. The purpose is to provide.

  The present invention is a functional device devised to achieve the above object. That is, an opening for forming a hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In the functional element including the side wall portion, the wall body has a width between both side surfaces narrower than a formation width of the upper surface portion, or includes the upper surface portion and the side wall portion. It is characterized by being formed wider than the maximum width of the stop film by a predetermined value or more.

  The present invention is also a functional device manufacturing method devised to achieve the above object. That is, an opening for forming a hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In the method of manufacturing a functional element including the side wall portion, the width between both side surfaces of the wall body is narrower than the formation width of the upper surface portion, or includes the upper surface portion and the side wall portion. The method includes a step of forming the wall body so as to be wider than a maximum width of the sealing film by a predetermined value or more.

  The present invention is also a devised fluid ejection device for achieving the above object. That is, an opening for forming the hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In the fluid ejecting apparatus configured using the functional element including the side wall portion having a width, the width between the both side surfaces of the wall body is narrower than the formation width of the upper surface portion, or the upper surface It is characterized by being formed wider than the maximum formation width of the sealing film including the portion and the side wall portion by a predetermined value or more.

  The present invention is also a devised printing apparatus for achieving the above object. That is, an opening for forming the hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In the printing apparatus configured using the functional element including the side wall portion having a fluid discharge device as the fluid discharge device, the width between the side surfaces of the wall body is narrower than the formation width of the upper surface portion. Alternatively, it is characterized in that it is formed wider than the maximum formation width of the sealing film including the upper surface part and the side wall part by a predetermined value or more.

In the functional device having the above configuration, the method of manufacturing the functional device having the above procedure, the fluid ejection device having the above configuration, and the printing device having the above configuration, the “formation width of the top surface portion” refers to the top surface portion and the inclined side wall portion. The formation width of the upper surface portion in the sealing film (for example, see FIG. 12) formed in a trapezoidal cross section, that is, the distance of the upper side in the trapezoidal shape (for example, see A in FIG. 12). Further, the “maximum formation width including the upper surface portion and the side wall portion” refers to a distance between long sides of the trapezoidal shape (see, for example, B in FIG. 12). This long side corresponds to the trapezoid lower side when the sealing film has a trapezoidal shape that spreads downward from the upper surface part, but when the sealing film has a trapezoidal shape that narrows downward from the upper surface part. The upper side of the trapezoid corresponds. If the upper side and the lower side are the same, either side may be the long side. Further, the “predetermined value” refers to a value set in advance based on formation conditions such as a wall forming material and exposure light intensity at the time of wall formation. For example, the “predetermined value” refers to exposure light in the wall forming material. This corresponds to the distance value at which the intensity of the reflected light can be attenuated.
Therefore, the width between both side surfaces of the wall formed on the sealing film is narrower than the formation width of the upper surface portion, or wider than the maximum formation width including the upper surface portion and the side wall portion by a predetermined value or more. In this case, both side surfaces of the wall body are arranged avoiding the side wall portions. That is, even when, for example, exposure to a photosensitive material is used at the time of forming the wall, the influence of irregular reflection on the side wall portion of the exposure light does not affect the formation of the wall.

  In the present invention, even if the sealing film has an inclined side wall portion, both side surfaces of the wall body are arranged avoiding the side wall portion, so that the influence of the irregular reflection of the exposure light on the side wall portion is exerted on the wall body. The variation in shape when forming the wall body can be kept small. Therefore, for example, when the flow path of the discharged fluid is constituted by the wall body, the flow resistance variation can be reduced. In other words, when used in a fluid discharge device, stable fluid ejection characteristics can be obtained, and uneven printing due to uneven discharge direction of the discharge target fluid and uneven discharge due to variations in discharge speed of the discharge target fluid are reduced. It becomes possible to do. Further, if the flow path wall runs over the vibration surface of the piezoelectric or electrostatic diaphragm, the amplitude is greatly reduced, and the discharge speed is lowered.

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

[Description of fluid ejection device and printing device]
First, prior to the description of the functional element, a fluid ejection device and a printing apparatus configured using the functional element 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. 1 is an explanatory diagram showing an outline of an ink jet 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. 1A, a paper 2 as a printing object is mounted on a roller 2 that feeds the paper 1 in the main scanning direction, and a carriage 3 that can move in the sub-scanning direction of the paper 1. The inkjet head 4 is provided. The inkjet head 4 ejects ink onto the paper 1 while moving the paper 1 and the carriage 3 to perform print output.
On the other hand, in the case of the line head type, as shown in FIG. 1B, the roller 2 for feeding the paper 1 in the main scanning direction and the ink discharge ports in a line shape along the sub-scanning direction of the paper 1 The inkjet head 5 is provided. Then, printing is performed by ejecting ink from each ejection port of the inkjet head 5 onto the paper 1 while moving the paper 1.
Note that the above-described configuration of the ink jet printer apparatus is an example of a printing apparatus, and the configuration is not particularly limited as long as printing can be performed by changing the relative positions of a head unit that ejects fluid and a printing object.

  By the way, in order to meet the need to print even higher image quality at high speed, whether it is a serial head or a line head system, the inkjet printer device does not increase power consumption, but reduces the ejection performance. In addition, it is required to further increase the number of pixels. In order to meet such a demand, some inkjet printer apparatuses are configured using inkjet heads 4 and 5 based on electrostatic MEMS. In the electrostatic MEMS system, the ink jet heads 4 and 5 are configured by using functional elements having a hollow structure portion, and vibrations in the functional elements are used as pressure application means to apply pressure to the paper 1. Ink is discharged. The constituent elements other than the ink jet heads 4 and 5 in the ink jet printer apparatus may be realized by a known technique, and the description thereof is omitted here.

  Next, a specific example of a fluid ejection device configured using an inkjet head, that is, a functional element, used in an inkjet printer apparatus will be described. However, here, only the main part of an ink jet head as a fluid ejection device configured using functional elements will be described regardless of whether the serial head method or the line head method is used. 2 to 5 are schematic views showing an example of the configuration of the main part of the fluid ejection device according to the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is a plan view thereof, and FIGS. .

  As shown in FIG. 2, the ink jet head described here includes a microfluidic drive unit 10 and a fluid supply unit 20 when roughly classified. Among these, the microfluidic drive unit 10 is formed by arranging a plurality of diaphragms 11 driven (vibrated) by electrostatic force in parallel at high density. On the other hand, the fluid supply unit 20 is disposed at a corresponding position on each diaphragm 11, and includes a pressure chamber (so-called cavity) 22 in which the ink liquid 21 that is a fluid is stored, and an outer wall for forming the pressure chamber 22. The flow path wall 23 and the nozzle plate 24, and a discharge portion (so-called nozzle) 25 for discharging the ink liquid 21 in the pressure chamber 22 to the outside are provided.

  As shown in FIGS. 3 to 5, in the microfluidic drive unit 10, a common substrate side electrode 13 made of a conductive material thin film is formed on a substrate 12, and an insulating film 14 is formed on the surface of the substrate side electrode 13. A plurality of diaphragm-side electrodes 16 and diaphragm 11 that are independently driven across a hollow structure space (hereinafter referred to as “hollow structure portion”) 15 so as to face the substrate-side electrode 13 are integrated. In addition, the support columns 17a are formed on the substrate 12 so as to be arranged in parallel and further to support the respective diaphragms 11 with both cantilever beams.

  Of these, the substrate 12 may be, for example, a substrate in which an insulating film 12b made of a silicon oxide film or the like is formed on a silicon substrate 12a. In addition, an insulating film may be formed on a semiconductor substrate such as gallium arsenide (GaAs). 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 13 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 16 may be formed of an impurity-doped polycrystalline silicon film, a metal film, an ITO film, or the like.

  The diaphragm 11 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 11 is formed by stacking these respective films, with silicon oxide films formed on the upper and lower surfaces of the SiN film. Moreover, the diaphragm 11 is formed in, for example, a strip shape, and is supported by a plurality of support columns 17a formed on the both sides thereof at predetermined intervals (inter-column pitch) 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 11 arranged in parallel are continuously formed through the support pillars 17 a, and the support pillars 17 a are also integrally formed of the same material as the vibration board 11. Therefore, the hollow structure portion 15 constituting the space between the diaphragm 11 and the substrate-side electrode 13 is communicated between the plural diaphragms 11 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 15 in the vicinity of the struts 17 a of each diaphragm 11, specifically, for example, between the struts 17 a along the longitudinal direction of one diaphragm 11. An opening 18 to be used is formed. Since the size of the opening 18 is likely to be closed as it is smaller, it can be considered to be □ 2 μm or less. However, if sacrificial layer etching is dry etching, □ 0.5 μm is sufficient.

  The opening 18 is closed by the sealing film 19 after the sacrifice layer etching. Details of the sealing film 19 will be described later.

  A diaphragm side electrode 16 is joined to the diaphragm 11 via an insulating film, and the diaphragm side electrode 16 is arranged so as to be inserted into a bent lower surface recess of the diaphragm 11. It shall be installed. Further, below the diaphragm 11, in order to increase the repulsive force when the diaphragm 11 is thinly formed, the auxiliary strut (so-called post) 17 b is provided in the vicinity of the central portion thereof together with the strut (so-called anchor) 17 a. May be formed.

  For such a microfluidic drive unit 10, the fluid supply unit 20 has a position that does not affect the vibration characteristics of each diaphragm 11 in the microfluidic drive unit 10, specifically, a sealing film that closes the opening 18. The flow path wall 23 is disposed on 19. Details of the position of the flow path wall 23 will be described later.

  The micro fluid driving unit 10 and the fluid supply unit 20 constitute an ink jet head. A fluid supply path (not shown) communicates with the pressure chamber 22 of the fluid supply unit 20 disposed on the microfluidic drive unit 10 in order to supply the ink liquid 21 into the pressure chamber 22. It shall be.

  Here, the processing operation in the ink jet head having the above configuration will be described. In the ink jet head, when a required voltage is applied between the substrate side electrode 13 and the diaphragm side electrode 16 in the microfluidic drive unit 10, an electrostatic attractive force is generated between the electrodes as shown in FIG. Thus, the diaphragm 11 integrated with the diaphragm side electrode 16 is bent toward the substrate side electrode 13. On the contrary, when the voltage application between the substrate side electrode 13 and the diaphragm side electrode 16 is released, the diaphragm 11 is released from the electrostatic attraction as shown in FIG. Damping vibration. Due to the volume fluctuation of the pressure chamber 22 in the fluid supply unit 20 due to the vertical vibration of the diaphragm 11, in the ink jet head, the ink liquid 21 in the pressure chamber 22 is ejected from the nozzle 25 to the outside, and the fluid enters the pressure chamber 22. The ink liquid 21 is supplied through the supply path.

  At this time, when the vibration plate 11 bends toward the substrate side electrode 13, the hollow structure portion 15 is a closed space, so the air in the hollow structure portion 15 is compressed and attempts to inhibit the deformation of the vibration plate 11. To do. However, if the diaphragm 11 is a support structure using the support column 17a, the auxiliary support column 17a, etc., the air compressed in the hollow structure portion 15 under the adjacent diaphragm 11 can be released, and as a result, the diaphragm can be sufficiently used. 11 can be bent.

[Description of functional elements]
Next, the functional element used in the ink jet head having the above configuration, that is, the functional element according to the present invention will be described in more detail. As described above, the functional element includes all elements having a hollow structure portion. As an example, there is an element used in an ink jet head, that is, one as shown in FIG. FIG. 7 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 described here has the hollow structure portion 15, so that the layer covering the hollow structure portion 15 constitutes the diaphragm 11, and a voltage is applied to the substrate side electrode 13. Thus, the diaphragm 11 can be vibrated.

  The hollow structure portion 15 is formed by sacrificial layer etching. That is, an etching layer serving as a sacrificial layer is laminated at a place where the hollow structure portion 15 is formed, and an etching resistant layer having an opening 18 is further laminated on the surface of the etching layer, and the etching layer is etched from the opening 18. After the removal, the opening 18 used for the removal is sealed. At this time, as a sacrificial layer to be etched, a sacrificial layer having a selection ratio with a constituent material of a layer other than the sacrificial layer is selected by an etchant. However, the formation of the hollow structure portion 15 is not necessarily limited to the sacrificial layer etching, and other known forming methods may be used.

The opening 18 is sealed by forming a sealing film 19 at the formation location. The sealing of the opening 18 by the sealing film 19 may be performed by either vapor deposition, sputtering, or PECVD (plasma-enhanced chemical vapor deposition). Further, as a material for forming the sealing film 19, aluminum (Al), nickel (Ni), chromium (Cr), copper (Cu), titanium (Ti), molybdenum (Mo), silver are used because of the ease of molding. (Ag), cobalt (Co), tantalum (Ta), platinum (Pt), gold (Au), tungsten (W), metals (such as silicon) and alloys thereof, oxide films such as SiO ₂ , or Although a nitride film etc. are mentioned, ceramics, resin, etc. previously formed can also be joined and used.

  However, it is assumed that the sealing film 19 is patterned so that the formation range remains in the vicinity of the opening 18 so as not to affect the vibration characteristics of the diaphragm 11. This patterning may be a problem of the selection ratio with the diaphragm 11 and dry etching, but is preferably performed using, for example, a known wet etching process in order to prevent the diaphragm 11 from being damaged by dry etching. Therefore, a metal that can be formed by a wet etching process is selected as a material for forming the sealing film 19.

  By the way, when patterning of the sealing film 19 is performed using a wet etching process, the side wall portion 19b of the sealing film 19 formed by the patterning usually has an inclination angle θ. That is, the sealing film 19 includes an upper surface portion 19a and a side wall portion 19b having an inclination θ, and the cross section thereof is formed in a trapezoidal shape. Note that the trapezoidal shape may be expanded downward from the upper surface portion 19a or may be narrowed downward from the upper surface portion 19a.

  A flow path wall (wall body) 23 constituting the pressure chamber 22 is formed on the sealing film 19. It is assumed that the wall body 23 is also patterned so as to overlap the sealing film 19 so as not to affect the vibration characteristics of the diaphragm 11. Therefore, the wall body 23 is formed of a photosensitive material such as a photosensitive resin or photosensitive glass. This is because it is very difficult to form the side wall surface into a nearly vertical shape or to suppress variations in the etching process, but when a photosensitive material is used, the etching process becomes unnecessary, and the etching width and depth are reduced. This is because the variation in thickness can be excluded.

  By the way, when the wall body 23 is formed of a photosensitive material, the light that has passed through the exposure mask when the photosensitive material is exposed causes irregular reflection at the side wall portion (inclined surface) of the sealing film. There is a fear (see, for example, FIG. 13). Such irregular reflection of the exposure light affects the formation of the wall body 23, and as a result, the shape of the wall body 23 varies greatly, which makes it difficult to obtain stable fluid ejection characteristics.

  Therefore, the wall body 23 is formed so that the width between both side surfaces thereof is narrower than the formation width of the upper surface portion 19a in the sealing film 19 as shown in FIG. 7A, for example. . Here, “the formation width of the upper surface portion 19a” refers to the distance of the upper side of the trapezoid in the trapezoidal sealing film 19 (see A in the figure). That is, when the width between both side surfaces of the wall body 23 is “C”, A> C.

  Further, for example, as shown in FIG. 7B, the wall 23 has a width between both side surfaces of a predetermined value or more than the maximum formation width including the upper surface portion 19 a and the side wall portion 19 b in the sealing film 19. It may be widely formed. Here, the “maximum formation width including the upper surface portion 19a and the side wall portion 19b” refers to the distance of the trapezoid long side in the trapezoidal sealing film 19 (see B in the figure). The long side corresponds to the trapezoidal lower side when the sealing film 19 has a trapezoidal shape extending downward from the upper surface part 19a, but the trapezoidal shape in which the sealing film 19 becomes narrower downward from the upper surface part 19a. In this case, the upper side of the trapezoid corresponds. If the upper side and the lower side are the same, either side may be the long side. Further, the “predetermined value” refers to a value set in advance based on the formation conditions such as the forming material of the wall body 23 and the exposure light intensity at the time of forming the wall body. For example, the exposure light in the forming material of the wall body This corresponds to the distance value at which the intensity of the reflected light with respect to can be attenuated (see D in the figure). Specifically, based on an empirical rule obtained through experiments or the like, it is conceivable that D ≧ 1 μm, preferably D = 3 μm.

  As described above, the wall 23 is formed such that the width between both side surfaces thereof is narrower than the formation width of the upper surface portion 19a or a predetermined value larger than the maximum formation width including the upper surface portion 19a and the side wall portion 19b. Either of these is widely formed. That is, the wall body 23 is disposed so as to avoid the side wall portion 19 b of the sealing film 19 on both wall surfaces on both sides thereof. Therefore, even if the wall body 23 is formed of a photosensitive material, the influence of irregular reflection on the side wall portion 19b of the exposure light used when forming the wall body 23 does not affect the formation of the wall body 23. The variation in shape when the wall body 23 is formed can be suppressed small.

  Therefore, even when the wall body 23 constitutes the pressure chamber 22, variation in resistance to the ink liquid 21 in the pressure chamber 22 can be reduced, and as a result, the ink liquid 21 discharged from the nozzle 25 to the outside. Stable fluid ejection characteristics can be obtained. That is, if an inkjet head is configured using the functional elements described in the present embodiment, uneven printing due to uneven ejection direction of the ink liquid 21, uneven printing due to uneven ejection speed of the ink liquid 21, and the like are reduced. Thus, a stable fluid ejection characteristic can be obtained with certainty.

[Description of Method for Manufacturing Functional Element]
Next, a method for manufacturing the functional element configured as described above will be described. However, the procedure for forming the hollow structure portion 15, the sealing film 19 and the wall body 23 will be mainly described here. FIG. 8 is an explanatory view showing an outline of a method for manufacturing a functional element according to the present invention.

  In manufacturing the functional element, first, as shown in FIG. 8A, the hollow structure portion 15 is formed by etching the sacrificial layer from the opening 18 formed in the diaphragm 11. However, instead of sacrificial layer etching, other known forming methods may be used. Note that the film thickness of the vibration plate 11 is determined in consideration of the bending and stress generated by etching the sacrificial layer, the bending and stress generated by forming the sealing film 19, and the like.

  After the hollow structure portion 15 is formed, the sealing film 19 is subsequently formed. That is, as shown in FIG. 8B, after forming a material for forming the sealing film 19 on the vibration plate 11 by vapor deposition, sputtering, or PECVD, as shown in FIG. The sealing layer 19 is formed by patterning the formed layer 19 ′ using, for example, a wet etching process.

  On the sealing film 19, as shown in FIG. 8D, a cover layer 31 for preventing intrusion of outside air or fluid may be formed. This is because if the sealing film 19 is covered with the cover layer 31, the sealing of the opening 18 by the sealing film 19 becomes even more reliable. As such a cover layer 31, a plasma silicon nitride (PE-SiN) film that has excellent moisture resistance and is effective in preventing intrusion of fluid or the like can be considered. However, the cover layer 31 is not necessarily required and may not be formed. Even in the case of film formation, the cover layer 31 is not necessarily a single layer such as a PE-SiN film, and may be a multilayer.

  Thereafter, the wall body 23 is formed. That is, as shown in FIG. 8E, a layer of a photosensitive material that is a material for forming the wall body 23 is formed on the vibration plate 11 on which the sealing film 19 is patterned, or on the cover layer 31 that covers them. 23 'is formed. An exposure mask (not shown) is used for the layer 23 ', and only the light passing through the exposure mask is irradiated onto the layer 23'. Thereby, as shown in FIG.8 (f), the wall body 23 is patterned and formed.

However, the mask for exposure used at this time has a mask pattern set as follows. That is, the width between both side surfaces of the wall body 23 is narrower than the formation width of the upper surface portion 19 a of the sealing film 19, or the maximum formation width including the upper surface portion 19 a and the side wall portion 19 b of the sealing film 19. Also, the mask pattern is set so as to be either wider than a predetermined value.
In addition, when the cover layer 31 is formed, the film thickness of the cover layer 31 shall also be considered. That is, as shown in an explanatory diagram of another example of the schematic configuration of the functional element in FIG. 9, the width between both side surfaces of the wall body 23 is the cover layer after the sealing film 19 is covered with the cover layer 31. It is either narrower than the formation width of the upper surface portion of 31 or wider than a maximum formation width of the cover layer 31 after the sealing film 19 is covered with the cover layer 31.

By patterning the wall body 23 using such an exposure mask, even if exposure light at the time of patterning causes irregular reflection at the side wall portion 19b of the sealing film 19 or the cover layer 31 covering this, It is possible to avoid the influence from affecting the formation of the wall body 23. That is, the wall body 23 can be formed in a state where the influence of the inclination angle θ of the side wall portion 19b is substantially eliminated. In addition, since the formation is performed by exposure to the photosensitive material, unlike the case of the etching process that scrapes the base material, it is very easy to form the side wall surface into a shape that is nearly vertical or to suppress the formation variation. Become.
In addition to the dimensions of the exposure mask, the width between both side surfaces of the wall body 23 can be adjusted by exposure parameters such as focus and exposure amount.

Then, after the wall body 23 is formed, the nozzle plate 24 is formed on the wall body 23 as shown in FIG. The nozzle plate 24 may be formed by bonding a film in which a hole to be the nozzle 25 is previously formed. Further, exposure is performed when forming the wall body 23 with a photosensitive material, and a film that becomes the nozzle plate 24 is formed by CVD or sputtering before the development is performed, and then a hole that becomes the nozzle 25 is formed. You may make it form by developing.
The functional element is configured through the above procedure.

[Description of other examples of functional elements]
Next, another embodiment of the functional element according to the present invention will be described. FIG. 10 is an explanatory diagram showing still another example of the schematic configuration of the functional element according to the present invention.

As described above, the wall body 23 formed on the sealing film 19 constitutes the pressure chamber 22, but when the height is lowered, the fluid resistance value is increased and the discharge efficiency is lowered. Therefore, the height of the wall body 23 is preferably set to 50 μm or more so as to avoid a decrease in discharge efficiency. However, when the height is 50 μm or more, it may be difficult to secure a sufficiently close contact area when forming the wall body 23 on the sealing film 19. Therefore, it is necessary for the wall body 23 to improve the adhesion with the sealing film 19 so as to be sufficiently stable even with a small adhesion area.
In addition, if the difference between the thermal expansion coefficients of the material of the wall body 23 and the sealing film 19 or the diaphragm 11 is large, excessive stress is generated at the interface between the wall body 23 and the sealing film 19a, and peeling occurs. As a countermeasure, it is important to improve the adhesion between the two.

  For this reason, in the functional element described here, irregularities are formed on the upper surface portion 19 a of the sealing film 19. And the wall body 23 is arrange | positioned on the unevenness | corrugation.

Specifically, for example, as shown in FIG. 10A, it is conceivable to form unevenness 19c on the sealing film 19 itself. Such unevenness 19c can be formed by performing stepwise etching when etching (patterning) the sealing film 19 using two or more types of exposure masks. It can also be formed by roughening the surface by dry etching or the like. Further, the unevenness 19c is naturally formed by sputtering Al thickly, or the impurities added to Al such as Al-Si, Al-Cu, etc. are selectively etched with, for example, XeF2, fuming nitric acid, etc. Can be formed. Alternatively, the surface of the SiO ₂ film is formed by altering the surface by a small amount by oxidation or the like to make the film thickness of the affected layer non-uniform and making the non-uniformity remarkable by selecting an etchant. Even if the unevenness 19c is formed by growing a film by selectively applying high energy to an electron beam or the like, or by roughening the surface by adjusting temperature conditions during film formation, etc. Good.

  Further, instead of making the sealing film 19 itself uneven, the sealing film 19 is sealed by bonding an uneven film 32 having unevenness to the upper surface portion 19a of the sealing film 19, for example, as shown in FIG. It is also conceivable to form irregularities on the film 19. Such an uneven film 32 can be formed by etching the overcoat film.

  Furthermore, as shown in FIG. 10C, for example, it is conceivable to form irregularities on the sealing film 19 by forming the irregularities 33 under the sealing film 19 in advance. Such an uneven portion 33 may be formed in advance before performing sacrificial layer etching. Further, if the concavo-convex portion 33 is made of the same material as that of the sacrificial layer or is a material that is etched by an etchant for sacrificial layer etching, it can be formed simultaneously with the sacrificial layer etching. Further, even after the sacrificial layer etching, it can be formed with the influence on the inside of the sacrificial layer being kept to a minimum by dry etching or the like. Even in the case of wet etching, formation after sacrificial layer etching can be performed by performing sufficient post-processing such as drying in a vacuum atmosphere.

  When the sealing film 19 is covered with the cover layer 31, that is, when the cover layer 31 is interposed between the sealing film 19 and the wall body 23, the unevenness as described above is provided in the cover layer. It is formed on the upper surface side of 31. Specifically, unevenness is formed on either the upper surface portion 19a of the sealing film 19 or the upper surface of the cover layer 31 under the sealing film 19, and as a result, the unevenness is formed on the upper surface side of the cover layer 31. Shall.

  When such unevenness is formed on the upper surface side of the sealing film 19 or on the upper surface side of the cover layer 31 when the cover layer 31 is interposed, the presence of the unevenness causes the wall 23 to be formed. This improves the adhesion. Therefore, even when the wall body 23 is formed with a height of 50 μm or more, it is possible to obtain adhesion that is sufficiently stable even with a small adhesion area, and peeling due to a difference in thermal expansion coefficient between different materials. Therefore, it is possible to realize prevention of a decrease in the discharge efficiency of the ink liquid 21 when an ink jet head is configured due to this.

  This is particularly effective when the width between both side surfaces of the wall body 23 is narrower than the formation width of the upper surface portion 19 a of the sealing film 19. If the width of the wall body 23 is narrower than the formation width of the upper surface portion 19a, it is more difficult to ensure a sufficiently stable contact area, and the side wall portion 19b of the sealing film 19 is prevented from being displaced. This is because there is no contribution. In other words, if unevenness is formed on the upper surface side of the sealing film 19 or the cover layer 31, even if the width of the wall body 23 is narrower than the formation width of the upper surface portion 19a, sufficient adhesion is obtained. Therefore, it is easy to cope with the narrow pitch of the nozzles 25.

In the present embodiment, the present invention has been described with reference to a suitable specific example. However, the present invention can be modified as appropriate without departing from the scope of the present invention.
For example, the film type / film thickness / formation method of the sealing film 19, the film type / film thickness / formation method of the wall body 23, the film type / film thickness / formation method of unevenness, etc. are the same as those described in the present embodiment. It is not limited and can be changed as appropriate.

  Further, the present invention can be widely applied to a functional element having a hollow structure portion, a manufacturing method thereof, and a fluid ejection device and a printing apparatus configured using the functional element, The present invention is not limited to the ink jet printer apparatus and the ink jet head described in the present embodiment. That is, the functional element according to the present invention is not only a fluid ejection device such as an inkjet head, but also a micropump, μTAS (Micro Total Analysis Systems), a DNA chip, a thermal diffusion device, other frequency filters, various sensors and relays. It can also be used as a switch or the like. In addition, a semiconductor element, a resonator, a vibrator, an FBAR (Film Bulk Acoustic Resonator), a SAW (surface acoustic wave) filter, a gyro sensor, a liquid crystal element, an organic electric field, etc. Light emitting 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 path, tube, The present invention can be applied even to an image sensor or the like.

It is explanatory drawing which shows the outline | summary of an inkjet printer apparatus. It is a perspective view which shows typically an example of the principal part structure of the fluid discharge apparatus which concerns on this invention. It is a top view which shows typically an example of a principal part structure of the fluid discharge apparatus which concerns on this invention. It is a sectional side view (the 1) which shows typically an example of a principal part structure of the fluid discharge apparatus which concerns on this invention, and is a figure which shows the AA cross section in FIG. It is a sectional side view (the 2) which shows typically an example of a principal part structure of the fluid discharge apparatus which concerns on this invention, and is a figure which shows the BB cross section in FIG. It is explanatory drawing which shows typically the outline | summary of the processing operation in the fluid discharge apparatus which concerns on this 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 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 other example of schematic structure of the functional element which concerns on this invention. It is explanatory drawing which shows the further another example of schematic structure of the functional element which concerns on this invention. It is explanatory drawing which shows an example of schematic structure of the conventional functional element. It is explanatory drawing which shows the example of formation of the sealing film of the conventional functional element. It is explanatory drawing which shows the generation | occurrence | production principle of halation at the time of the flow formation of the conventional functional element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Paper, 2 ... Roller, 3 ... Carriage, 4, 5 ... Inkjet head, 10 ... Micro fluid drive part, 11 ... Vibration board, 12 ... Substrate, 13 Substrate side electrode, 14 ... Insulating film, 15 ... Hollow structure part , 16 ... Diaphragm side electrode, 17a ... Column (anchor), 17b ... Auxiliary column (post), 18 ... Opening, 19 ... Sealing film, 19a ... Top surface, 19b ... Side wall, 19c ... Concavity / convexity, 20 ... Fluid Supply part, 21 ... Ink liquid, 22 ... Pressure chamber (cavity), 23 ... Channel wall (wall body), 31 ... Cover layer, 32 ... Concave film, 33 ... Concave film

Claims (16)

An opening for forming a hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film has an upper surface portion and an inclination. In a functional element comprising a side wall,
The wall is formed such that a width between both side surfaces thereof is narrower than a formation width of the upper surface portion, or wider than a maximum formation width of the sealing film including the upper surface portion and the side wall portion. A functional element characterized by being. The functional element according to claim 1, wherein the upper surface portion has unevenness, and the wall body is formed on the unevenness. A single-layer or multiple-layer cover layer is formed between the sealing film and the wall body,
The wall is formed such that the width between both side surfaces thereof is narrower than the formation width of the upper surface portion of the cover layer, or wider than the maximum formation width of the cover layer by a predetermined value or more. The functional element according to claim 1. The functional element according to claim 3, wherein an upper surface side of the cover layer laminated on the upper surface portion has unevenness, and the wall body is formed on the unevenness. An opening for forming a hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film has an upper surface portion and an inclination. In a method for manufacturing a functional element comprising a side wall part,
A width between both side surfaces of the wall body is narrower than a formation width of the upper surface portion, or larger than a maximum formation width of the sealing film including the upper surface portion and the side wall portion by a predetermined value or more. And a step of forming the wall body. The method for manufacturing a functional element according to claim 5, further comprising: forming irregularities on the upper surface portion. Including a step of forming a single-layer or multiple-layer cover layer between the sealing film and the wall body,
In the step of forming the wall body, the width between both side surfaces of the wall body is narrower than the formation width of the upper surface portion of the cover layer or larger than the maximum formation width of the cover layer by a predetermined value or more. The method of manufacturing a functional element according to claim 5, further comprising: forming the wall body. The method of manufacturing a functional element according to claim 7, further comprising: forming irregularities on an upper surface side of the cover layer laminated on the upper surface portion. An opening for forming the hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In the fluid ejection device configured using the functional element including the side wall portion,
The wall is formed such that a width between both side surfaces thereof is narrower than a formation width of the upper surface portion, or wider than a maximum formation width of the sealing film including the upper surface portion and the side wall portion. A fluid discharge device characterized in that The fluid ejection device according to claim 9, wherein the upper surface portion has irregularities and the wall body is formed on the irregularities. A single-layer or multiple-layer cover layer is formed between the sealing film and the wall body,
The wall is formed such that the width between both side surfaces thereof is narrower than the formation width of the upper surface portion of the cover layer, or wider than the maximum formation width of the cover layer by a predetermined value or more. The fluid ejection device according to claim 9. The fluid ejection device according to claim 11, wherein an upper surface side of the cover layer laminated on the upper surface portion has unevenness, and the wall body is formed on the unevenness. An opening for forming the hollow structure portion, a sealing film for sealing the opening, and a wall formed on the sealing film are provided, and the sealing film is inclined with respect to the upper surface portion. In a printing apparatus configured by using a functional element including a sidewall portion as a fluid ejection device,
The wall is formed such that a width between both side surfaces thereof is narrower than a formation width of the upper surface portion, or wider than a maximum formation width of the sealing film including the upper surface portion and the side wall portion by a predetermined value or more. The printing apparatus characterized by being made. The printing apparatus according to claim 13, wherein the upper surface portion has unevenness, and the wall body is formed on the unevenness. A single-layer or multiple-layer cover layer is formed between the sealing film and the wall body,
The wall is formed such that the width between both side surfaces thereof is narrower than the formation width of the upper surface portion of the cover layer, or wider than the maximum formation width of the cover layer by a predetermined value or more. The printing apparatus according to claim 13. The printing apparatus according to claim 15, wherein an upper surface side of the cover layer laminated on the upper surface portion has unevenness, and the wall body is formed on the unevenness.

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