JP2006281639A - Functional device, its manufacturing method, and liquid jetting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a wiring pattern on the board is short-circuited when metallic foreign matters are peeled off, the metallic foreign matters enter a hole section like an ink passage in the substrate of an inkjet head and the nozzle of the liquid jetting head is clogged by preventing the over-etching of the recess section from occurring and preventing metallic foreign matters from remaining on the bottom surface of the recess section when a recess for releasing an adhesive is formed. <P>SOLUTION: This functional device is formed by a plurality of the boards are bonded with an adhesive. In the functional device, the recess section which becomes a region for releasing the excessive adhesive is formed at least on one of the bonding surfaces of the boards which are bonded to each other. The shape of the opening section of the recess section is formed in such a manner that the acute angle of which may not become the direction side being orthogonal with the crystal orientation 3 of the board. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a functional device such as a liquid ejecting head and a manufacturing method thereof. Specifically, the present invention relates to an improvement in a structure for joining a plurality of substrates with an adhesive.

FIG. 1 and FIG. 2 of Japanese Patent Laid-Open No. 2002-210965 (Patent Document 1) have a plurality of nozzle openings 21 that are made of a silicon single crystal substrate and discharge droplets, and are in communication with the nozzle openings 21. A nozzle plate 20 is described that is bonded to a flow path forming substrate 10 on which a path is formed via an adhesive. This nozzle plate has a plurality of recesses 23 formed by half-etching in a region serving as a joint surface with the flow path forming substrate 10, so that it is wasteful when bonding the nozzle plate and the flow path forming substrate. The adhesive is allowed to flow into the recess. This prevents excess adhesive from flowing into the ink flow path.
Japanese Patent Laid-Open No. 2002-210965

  In the nozzle plate of Patent Document 1, as shown in FIGS. 1 and 2, a reservoir constituting at least a part of the reservoir 100 is provided on the piezoelectric element 300 side of the flow path forming substrate 10 in which the pressure generating chamber 12 and the like are formed. A reservoir forming substrate 30 having a portion 31 is joined. A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to the reservoir forming substrate 30.

  Since the reservoir substrate and the compliance substrate are also bonded with an adhesive, it is necessary to form the above-described recesses on the bonding surface of at least one of the substrates. These recesses need to be formed as deep as possible to accommodate excess adhesive, and since it is necessary to arrange a large number of recesses on the substrate, the crystal orientation of the silicon substrate is taken into consideration for ease of layout. One having a rhombus (or parallelogram) -shaped opening composed of a plurality of sides is considered preferable as the recess.

  FIG. 5 shows the orientation of each crystal orientation in the orientation of the orientation flat in the silicon wafer having the crystal orientation (110). The (111) plane that forms an angle of 90 ° with respect to (110) is determined by crystal orientation 1 and crystal orientation 2, and the (111) plane that forms an angle of about 35 ° with respect to (110) is determined by crystal orientation 3 . It is the shape (eg, width) of the opening in the direction perpendicular to the crystal orientation 3 that dominates the depth of the recess. Therefore, even if the area of the opening of the recess is the same, the etching is shallow or deep due to the difference in the width in the direction perpendicular to the crystal orientation 3. As described above, the etching of the concave portion can be deeply formed by increasing the direction distance perpendicular to the crystal orientation 3 of the opening.

  However, the shape of the recess as described above has the following problems. First, when forming a wiring pattern on a substrate having a recess, the resist enters deeply into the recess, and the resist is difficult to remove during exposure and development of the resist, and the metal film remains in the recess. End up. In order to remove the metal foreign matter in the concave portion, it is conceivable to add a surfactant to the developer and lengthen the metal etching time, but this is not sufficient, so that the foreign matter made of metal does not remain in the concave portion. It was not realized. For this reason, there is a problem that the adhesion strength between the substrates decreases due to a foreign substance made of metal. In addition, there is a possibility that metal foreign matter enters the ink in the ink flow path and closes the ink nozzle.

  Second, when the acute angle of the opening of the concave portion is on the direction side perpendicular to the crystal orientation 3, overetching occurs when the concave portion is formed by etching the substrate. There is a problem that a crack is generated in the substrate from the concave portion. Therefore, the concave portion cannot be formed in the vicinity of the hole corresponding to the ink introduction port and the ink introduction path formed in the substrate. When the concave portion is brought close to the hole, there is a problem that a crack is generated in the substrate, so that ink leaks to a wiring pattern formed on the substrate and a plurality of wirings are short-circuited. On the other hand, when the concave portion is formed at a position away from the hole, it is difficult to sufficiently accommodate the concave portion so that excess adhesive does not go to the hole side.

  Therefore, in order to solve such a problem, the present invention provides a functional device formed by bonding a plurality of substrates with an adhesive, and an extra adhesion to at least one of the bonding surfaces of the substrates to be bonded to each other. A recess serving as a region for escaping the agent is formed, and the shape of the opening of the recess is formed so that an acute angle is not on a direction perpendicular to the crystal orientation 3 of the substrate. Is.

  That is, according to the present invention, the recess is prevented from being over-etched by being formed on the substrate so that the acute angle of the opening of the recess is not on the direction orthogonal to the crystal orientation 3 of the substrate. To avoid becoming too deep. Accordingly, it is possible to solve the problem that it is difficult for cracks to be generated in the substrate from the recesses, and the metal foreign matter remaining deep in the recesses cannot be removed by forming the recesses shallowly.

  Furthermore, by making the opening end shape of the concave portion into a polygonal shape, the surface area of the opening can be increased without deepening the opening portion, and extra adhesive that leaks from the bonding surface when the substrates are bonded together is sufficiently accommodated in the concave portion. It becomes possible.

  The shape of the opening includes a parallelogram, a rhombus, or a polygon. According to this polygonal shape, the area of the opening can be increased without increasing the diameter of the opening. Therefore, even if the depth of the recess becomes shallow, the adhesive is bonded to the bonding surface between the substrates in the recess. It can be accommodated so that it will not flow out of it. The upper limit of the polygon is not limited. However, when a silicon substrate having a crystal orientation (110) is used, three types of angles, crystal orientation 1, crystal orientation 2, and crystal orientation 3, are used due to restrictions due to anisotropic etching. The upper limit is preferably the hexagon formed.

  It is also preferable to form the opening in an arc shape, but in the case of a silicon substrate, it is difficult to form the opening in an arc shape due to anisotropic etching.

  The functional device of the present invention includes a liquid ejecting head and other devices in which predetermined elements are formed on a substrate.

  Next, an embodiment of an ink jet head which is one aspect of the liquid jet head according to the present invention will be described. FIG. 1 is an exploded perspective view showing an inkjet head, and FIG. 2 is a sectional view thereof. One surface of the ink flow path forming substrate 10 serves as an opening surface, and an elastic film 50 having a thickness of 1 to 2 μm made of silicon dioxide previously formed by thermal oxidation is formed on the other surface.

  In the flow path forming substrate 10, pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction by anisotropically etching a silicon single crystal substrate. On the outer side in the longitudinal direction, there is formed a communication portion 13 that forms part of the reservoir 100 that communicates with the reservoir portion 31 of the reservoir forming substrate 30 and serves as a common ink chamber for each pressure generating chamber 12. 12 communicated with one end portion in the longitudinal direction via an ink supply path 14.

  On the other surface side of the flow path forming substrate 10, a nozzle plate 20 in which a nozzle opening 21 communicating with the side opposite to the ink supply path 14 of each pressure generating chamber 12 is formed is joined by an adhesive. The nozzle opening 21 is formed by dry etching the silicon single crystal substrate. The nozzle opening 21 includes a nozzle portion 21 a from which ink droplets are ejected, and a nozzle communication portion 21 b that is formed with a larger diameter than the nozzle portion 21 a and communicates the nozzle portion 21 a and the pressure generation chamber 12.

  The nozzle plate 20 is provided with a plurality of recesses 23 along the periphery of each pressure generation chamber 12 in a region corresponding to the periphery of the pressure generation chamber 12, for example, a portion bonded to the flow path forming substrate 10. By providing such a recess 23, when the nozzle plate 20 and the flow path forming substrate 10 are bonded via an adhesive, a wasteful adhesive flows into the recess 23. It is possible to prevent excessive flow into the inside.

  The crater portion 22 and the recess portion 23 can be formed in the same process by simultaneously anisotropically etching the silicon single crystal substrate from both sides. The shape of the opening of the recess will be described later.

  On the elastic film 50 provided on the flow path forming substrate 10, a lower electrode film 60 with a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 with a thickness of, for example, about 0.5 to 3 μm, For example, the upper electrode film 80 having a thickness of about 0.1 μm is laminated to form the piezoelectric element 300. The piezoelectric element 300 includes a lower electrode film 60, a piezoelectric layer 70, and an upper electrode film 80. The lower electrode film 60 serves as a common electrode for the piezoelectric element 300.

  As shown in FIGS. 1 and 2, a reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 on the piezoelectric element 300 side of the flow path forming substrate 10 in which the pressure generating chambers 12 and the like are formed. Are joined. The reservoir portion 31 is formed across the width direction of the pressure generating chamber 12 through the reservoir forming substrate 30 in the thickness direction. The reservoir portion 31 is communicated with the communicating portion 13 of the flow path forming substrate 10 through a through hole 51 provided through the elastic film 50 and the lower electrode film 60, so that the common ink of each pressure generating chamber 12 is used. A reservoir 100 serving as a chamber is configured.

  As the reservoir forming substrate 30, a silicon single crystal substrate having a crystal orientation (plane orientation) of (110) was used. As in the case of the nozzle plate 20, the flow path forming substrate 10 and the reservoir forming substrate 30 can be reliably bonded by high-temperature bonding using a thermosetting adhesive. A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to the reservoir forming substrate 30. Since the region of the fixing plate 42 that faces the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. The flexible portion 32 is deformable by a change in internal pressure.

  An ink introduction port 35 for supplying ink to the reservoir 100 is formed on the compliance substrate 40 on the outer side of the central portion of the reservoir 100 in the longitudinal direction. Further, the reservoir forming substrate 30 is provided with an ink introduction path 36 that allows the ink introduction port 35 and the side wall of the reservoir 100 to communicate with each other.

  In a region facing the piezoelectric element 300 of the reservoir forming substrate 30, a piezoelectric element holding portion 33 that secures a space that does not hinder the movement of the piezoelectric element 300 is provided. At least the piezoelectric active part 320 of the piezoelectric element 300 is formed in the piezoelectric element holding part 33 to prevent the destruction of the piezoelectric element 300 due to an external environment such as moisture in the atmosphere. The electric element holding portion 33 may not be completely sealed, but has a structure that should not be in a state where it is easily affected by the outside.

  The ink jet recording head takes in ink from an ink introduction port 35 connected to an external ink supply means (not shown), fills the interior from the reservoir 100 to the nozzle opening 21, and then follows a recording signal from an external drive circuit. A voltage is applied between the upper electrode film 80 and the lower electrode film 60 to cause the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 to bend and deform, thereby increasing the pressure in the pressure generating chamber 12 and opening the nozzle. 21. Ink droplets are ejected from the recording medium or object. A wiring pattern is formed on the flow path forming substrate 30 to connect the upper and lower electrodes from an external circuit.

  FIG. 3 is a plan view (partially enlarged view) of the reservoir forming substrate 30. A wiring 500 is formed on the substrate 30, and grooves 502 having parallelogram openings serving as recesses are formed on both sides of the wiring 500 in rows while being close to the wiring. FIG. 4 is also a plan view of the flow path forming substrate 30, but the magnification is smaller than that of FIG. 3, and a plurality of concave portions 503 are formed around the holes 504 formed in the flow path forming substrate. Has been.

  The recess is formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching). This concave portion is provided in order to prevent the adhesive from leaking out from the bonding surfaces of the substrates to be bonded to each other in the same manner as the above-described concave portion 23.

  FIG. 5 shows the orientation of each crystal orientation in the orientation of the orientation flat in the silicon single crystal substrate 600 having the crystal orientation (110). The (111) plane that forms an angle of 90 ° with respect to (110) is determined by crystal orientation 1 and crystal orientation 2, and the (111) plane that forms an angle of about 35 ° with respect to (110) is determined by crystal orientation 3 . It is the shape (eg, width) of the opening in the direction perpendicular to the crystal orientation 3 that dominates the depth of the recess.

  602 in FIG. 6 shows a parallelogram (diamond) state in which the shape of the opening of the concave portion is composed of two angles of crystal orientation 1 and crystal orientation 2. In this shape, since there is an acute angle in the direction orthogonal to the crystal orientation 3, overetching occurs when the silicon single crystal substrate 600 is etched, the depth of the concave portion is increased, and the silicon single crystal substrate 600 is easily cracked. Become.

  Reference numeral 604 denotes a parallelogram (diamond) state in which the shape of the opening of the concave portion is composed of two angles of crystal orientation 1 and crystal orientation 3. In this shape, the acute angle of the parallelogram opening is not in the direction perpendicular to the crystal orientation 3, so that if the opening shape has such a relationship, the recess is over-etched in the depth direction. Can be prevented.

As a result of investigation by the present inventor, when all the conditions are the same, by changing the shape of the opening from 602 to 604, the depth of the latter recess is reduced to (1/3) ^1/2 of the former. Thus, the number of generated metal foreign objects was 1/10 of the former in the latter.

  Reference numeral 606 denotes a parallelogram (rhombus) state in which the shape of the opening of the recess is composed of two angles of crystal orientation 2 and crystal orientation 3. Reference numeral 608 denotes a hexagonal state in which the shape of the opening of the recess is composed of three angles of crystal orientation 1, crystal orientation 2, and crystal orientation 3.

  As the concave portion having the above-described characteristics, it is preferable to make the concave portion more polygonal when the diameter of the concave opening portion is the same. By making it polygonal, the surface area of the opening is increased, and more adhesive can be released into the recess even when the depth of the recess is reduced.

  Since the recess according to the present invention has an opening shape that does not form an acute angle on the direction orthogonal to the crystal orientation 3, there is no problem of over-etching, and the recess can be provided close to the ink flow path and the wiring. .

  Also, if there is an acute angle of the opening on the direction orthogonal to the crystal orientation 3, the recess should not be separated from the end of the hole or the end of the wiring in order to prevent foreign matter from entering the ink channel due to cracking problems. must not. By providing the recess in contact with the hole or the wiring, when the recess is provided in the vicinity of the wiring without adhering the adhesive protruding from the bonding surface of the substrate in the vicinity of the hole to the ink flow path, foreign matter may come into contact with the wiring. As a result, the wiring is not short-circuited, and the adhesive can be reliably stored in the recess.

  In the arrangement of the recesses in the vicinity of the flow path or the wiring, the plurality of recesses are arranged in a line along the flow path or the wiring. In particular, by providing the recesses in a plurality of rows, a larger amount of excess resin can be released to the recesses. In particular, by forming the recesses in a polygonal shape, particularly in a hexagonal shape, the recesses can be formed in a staggered pattern so as to form a plurality of rows even if the wiring and the holes are inclined.

  In the present embodiment, the substrate in which the concave portion is formed is the nozzle plate 20 and the reservoir forming substrate 30, but is not limited thereto, and can be expanded to a substrate in which holes such as nozzle openings and wiring are performed.

  In the above-described embodiment, the ink jet head has been described as an example of the liquid ejecting head. However, the present invention is widely intended for the entire liquid ejecting head, and the liquid ejecting ejects a liquid other than ink. Of course, the present invention can also be applied to a head manufacturing method. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (surface emitting displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

1 is a perspective view of an inkjet head according to the present invention. It is sectional drawing of the ink head jet. It is a top view of the board | substrate with which the recessed part of this invention was formed. It is a top view of the other example of the board | substrate with which the recessed part of this invention was formed. It is the top view which showed crystal orientation 1, 2, and 3 of the silicon wafer of crystal orientation (110). It is the top view which showed the formation direction of the recessed part, and the several shape of the opening part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Ink flow path formation board | substrate, 20 Nozzle plate, 21 Nozzle opening, 30 Reservoir formation board | substrate, 300 Piezoelectric element, 500 Wiring, 502 Groove, 503 Row-shaped recessed part, 504 Hole part, 600 Silicon single crystal substrate, 602, 604, 606, 608 recess

Claims (7)

In a functional device formed by bonding a plurality of substrates with an adhesive,
At least one of the bonding surfaces of the substrates to be bonded to each other is formed with a recess serving as an area for excess adhesive to escape,
A functional device in which the shape of the opening of the concave portion is formed such that the acute angle portion does not become a direction side orthogonal to the crystal orientation that governs the depth direction of the substrate.   The functional device according to claim 1, wherein the shape of the opening is formed such that an obtuse angle portion is on a direction side orthogonal to a crystal orientation that governs the depth direction of the substrate.   The functional device according to claim 1, wherein the shape of the opening is a parallelogram, a rhombus, or a polygon.   The functional device according to claim 3, wherein the polygonal opening is a hexagonal or more polygonal opening.   A hole penetrating the substrate and / or a wiring is formed in the substrate, and the recess is formed by half etching with respect to the substrate so that the concave portion is formed in a plurality of rows around the hole and / or the wiring. The device according to claim 1. In a liquid ejecting head formed by joining a plurality of substrates with an adhesive and forming a liquid flow path for supplying liquid to a nozzle opening for discharging droplets,
At least one of the bonding surfaces of the substrates to be bonded to each other, a recess is formed in the periphery of the hole serving as the liquid flow path and the periphery of at least one of the wiring part, which serves as a region for excess adhesive to escape,
A liquid ejecting head, wherein the opening of the concave portion is formed so as to have the shape according to claim 1. In a method of manufacturing a functional device by bonding a plurality of substrates with an adhesive,
On at least one of the bonding surfaces of the substrates to be bonded to each other, a recess that becomes a region for escape of excess adhesive is formed,
The manufacturing method of the functional device formed so that the shape of the opening part of the said recessed part might turn into the shape in any one of Claims 1-5.

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