Head chip manufacturing method

Abstract

To provide a method for manufacturing a head chip which prevents variations in volumes of each channel.SOLUTION: When air escape grooves 13b extending in a second direction Y substantially perpendicular to a first direction X are formed so as to penetrate through or come in contact with a plurality of channel grooves 13 extending in the first direction X, so that at least the channel groove 13 on one end communicates with the other end of a wafer 10, air in the channel grooves 13 results in escaping to the outside of the wafer 10 from the air escape grooves 13b, and accordingly an adhesive results in equally flowing into the air escape grooves 13b in a laminated substrate manufacturing process P6, and a head chip which prevents variations in volumes of channels and has stable discharge performance when being mounted on a droplet discharge device can be manufactured.SELECTED DRAWING: Figure 5A

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a head chip.

Background Art

[0002] Conventionally, as a method for manufacturing a head chip of a droplet ejection device, a manufacturing method is known in which a plurality of substrates having an ink / air channel formed therein are laminated, joined by an adhesive, and then cut (see, for example, Patent Document 1). At this time, in order for the substrates to be sufficiently joined, it is necessary to use an amount of adhesive such that a fillet is formed in the channel by overflowing from the joining portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the invention of Patent Document 1, the adhesive overflows unevenly from the joining portion, and non-uniform fillets are formed in each channel portion. As shown in the graph of FIG. 12, when the volume of the channel varies due to the non-uniform fillets, the AL (Acoustic Length) changes accordingly, so that when droplets are ejected from the head chip, a desired ejection speed cannot be obtained.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a head chip in which variations in the volume of each channel are unlikely to occur.

Means for Solving the Problems

[0006] To solve the above problems, the invention described in claim 1 is a method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The aforementioned air vent groove forming step is, At the end of the channel groove in the first direction, the curved portion formed in a curved shape, The air vent groove is formed such that at least one end communicates with the edge of the first substrate. Furthermore, in order to solve the above problems, the invention described in claim 2 is a method for manufacturing a head chip, An electrode formation step of forming electrodes in the channel grooves of a first substrate having a plurality of channel grooves extending in a first direction formed on its first surface, A capacitance testing step for testing the electrical capacitance of the electrode, An air vent groove forming step is to form an air vent groove on the first surface of the first substrate that extends in a second direction substantially perpendicular to the first direction and penetrates the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The air vent groove forming step involves forming the air vent groove such that at least one end communicates with the end of the first substrate. The electrode formation step and the capacity inspection step are performed before the air vent groove formation step. Furthermore, in order to solve the above problems, the invention described in claim 3 is a method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, A laminated substrate manufacturing process involves bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The process includes a cutting step of dividing the laminated substrate into a portion including the air vent groove and a head chip portion, The air vent groove forming step involves forming the air vent groove such that at least one end communicates with the edge of the first substrate. Furthermore, in order to solve the above problems, the invention described in claim 4 is a method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The air vent groove forming step involves forming the air vent groove such that at least one end communicates with the end of the first substrate. The aforementioned laminated substrate manufacturing process involves joining multiple laminated substrates, each formed by joining the first substrate and the second substrate, together with an adhesive.

[0007] Furthermore, in order to solve the above problems, 5 The invention described is a method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air escape groove forming step is a step performed prior to the laminated substrate manufacturing step, and the air escape groove is formed such that at least one end communicates with the end of the second substrate Furthermore, the air vent groove abuts against the curved portion formed in a curved shape at the first end of the channel groove of the first substrate. and the laminated substrate manufacturing step joins the first substrate and the second substrate such that the plurality of channel grooves and the air escape groove abut. The laminated substrate manufacturing step joins the first substrate and the second substrate such that the plurality of channel grooves and the air escape groove abut. Furthermore, in order to solve the above problems, the invention described in claim 6 is a method for manufacturing a head chip, An electrode formation step of forming electrodes in the channel grooves of a first substrate having a plurality of channel grooves extending in a first direction formed on its first surface, A capacitance testing step for testing the electrical capacitance of the electrode, A laminated substrate manufacturing process in which the second surface of a second substrate is bonded to the first surface of the first substrate with an adhesive to form a laminated substrate, The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The laminated substrate manufacturing process involves joining the first substrate and the second substrate such that the plurality of channel grooves and the air vent grooves are in contact with each other. The invention described in claim 7 is a method for manufacturing a head chip as described in claim 6, The electrode formation step and the capacity inspection step are performed before the air vent groove formation step. Furthermore, in order to solve the above problems, the invention described in claim 8 is a method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; An air vent groove forming step is performed on the second surface of the second substrate, forming an air vent groove extending in a second direction substantially perpendicular to the first direction, The process includes a cutting step of dividing the laminated substrate into a portion including the air vent groove and a head chip portion, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The laminated substrate manufacturing process involves joining the first substrate and the second substrate such that the plurality of channel grooves and the air vent grooves are in contact with each other. Furthermore, in order to solve the above problems, the invention described in claim 9 is a method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The laminated substrate manufacturing process involves bonding multiple laminated substrates, each formed by bonding the first substrate and the second substrate, together with an adhesive such that the multiple channel grooves and the air vent grooves are in contact with each other.

[0008] Claim 10 The invention described in claim 1 any one of the 9 terms is a method for manufacturing the head chip described in claim 1, wherein the laminated substrate manufacturing step joins the second substrate to the first substrate so as to cover the entire surface of the channel groove.

[0013] Claim 11The invention described is as follows: any one of the 9 terms The method for manufacturing the head chip described above, The aforementioned laminated substrate manufacturing process involves bonding the second substrate to the first substrate by applying heat treatment and pressure treatment to the first substrate and the second substrate which are joined together with an adhesive.

[0015] Claim 12 The invention described is as follows: any one of the 9 terms The method for manufacturing the head chip described above, The aforementioned laminated substrate manufacturing process involves forming a fillet made of adhesive within the channel groove. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a method for manufacturing a head chip in which variations in the volume of each channel are less likely to occur. [Brief explanation of the drawing]

[0018] [Figure 1] This is a flowchart showing the steps of the manufacturing process for the head chip according to the first embodiment. [Figure 2] This is a side view showing the wafer's structure. [Figure 3A] This is a perspective view showing the channel groove formation process. [Figure 3B] Figure 3A is a cross-sectional view along the line IIIB-IIIB. [Figure 4] This is an enlarged cross-sectional view showing one channel groove on which an electrode is formed. [Figure 5A] This is a top view showing a wafer with air vent grooves formed on it. [Figure 5B] Figure 5A is a cross-sectional view along the VB-VB line. [Figure 6A] This is a side cross-sectional view showing one embodiment of a laminated substrate in which multiple wafers and a cover substrate are bonded together. [Figure 6B] This is a side cross-sectional view showing another embodiment of a laminated substrate in which multiple wafers and a cover substrate are bonded together. [Figure 6C]This is a side cross-sectional view showing another embodiment of a laminated substrate in which multiple wafers and a cover substrate are bonded together. [Figure 7] This is a side cross-sectional view showing a laminated substrate in which wafers of equal width in the first direction are bonded to a cover substrate. [Figure 8] This is a side cross-sectional view showing the cutting process. [Figure 9A] This graph shows the measured AL (Area of ​​Alt) at which the droplet ejection velocity is maximized in each channel of a wafer with a narrow cover substrate bonded to the first surface of a laminated substrate that has air vent grooves formed on it. [Figure 9B] This graph shows the measured AL (Area of ​​Alt) at which the droplet ejection velocity is maximized in each channel of a wafer with an air vent groove formed on a laminated substrate, where a wafer of equal width is bonded to the first surface. [Figure 10A] This graph shows the measured AL (Area of ​​Alt) at which the droplet ejection velocity is maximized in each channel of a wafer with a narrow cover substrate bonded to the first surface of a laminated substrate that does not have air vent grooves. [Figure 10B] This graph shows the measured AL (Area of ​​Alt) at which the droplet ejection velocity is maximized in each channel of a wafer with a wafer of equal width bonded to the first surface of a laminated substrate that does not have air vent grooves. [Figure 11] This is a side cross-sectional view showing a laminated substrate according to the second embodiment. [Figure 12] This graph shows the measured AL (Amount of Liquid Release) at which the droplet discharge velocity is maximized in each channel with different volumes. [Modes for carrying out the invention]

[0019] The method for manufacturing a head chip according to the present invention will be described in detail below with reference to the drawings. However, the embodiments described below are subject to various technically preferred limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

[0020] [First Embodiment] First, the method for manufacturing a head chip according to the first embodiment is shown. As shown in Figure 1, the method for manufacturing a head chip according to the first embodiment includes a substrate manufacturing step P1, a channel groove formation step P2, an electrode formation step P3, a capacitance inspection step P4, an air vent groove formation step P5, a laminated substrate manufacturing step P6, and a cutting step P7.

[0021] (Substrate manufacturing process) First, as a substrate manufacturing process P1, as shown in Figure 2, two piezoelectric element substrates 12a and 12b, which have undergone polarization treatment, are bonded to a substrate 11 made of, for example, ceramics, to create a wafer 10 that constitutes a head chip having a piezoelectric element layer on its surface.

[0022] As the piezoelectric material used for each piezoelectric element substrate 12a and 12b, known piezoelectric materials that deform when a voltage is applied, such as lead zirconate titanate (PZT), can be used. The two piezoelectric element substrates 12a and 12b are stacked with their polarization directions (indicated by arrows) in opposite directions and joined to the substrate 11 using an adhesive.

[0023] (Channel groove formation process) Next, in the channel groove formation process P2, cutting is performed on the wafer 10 in the first direction X to form channel grooves 13 that will become ink / air channels in the head chip. Figure 3A is a perspective view showing this process, and Figure 3B is a cross-sectional view of the wafer 10 in which the channel grooves 13 have been formed, in the second direction Y (line IIIB-IIIB in Figure 3A) which is approximately perpendicular to the channel grooves 13.

[0024] As shown in Figure 3A, in this process, a plurality of channel grooves 13 are formed on the first surface of the wafer 10 by cutting using a rotating blade such as a dicing blade. As a result of this process, as shown in Figure 3B, drive walls 14 made of piezoelectric elements with opposite polarization directions in the height direction are arranged side by side between adjacent channel grooves 13.

[0025] This process is not limited to using a dicing blade. However, using a dicing blade is preferable because it allows for high-precision cutting of the channel groove width 13, resulting in parallel channel grooves 13.

[0026] Furthermore, in this process, it is preferable to form a curved portion 13a at the end of the channel groove 13 in the first direction X, as shown in Figure 3A. Forming a curved portion 13a at the end of the channel groove 13 increases the fluidity of the liquid. Therefore, it becomes easier to form a metal coating in the subsequent electrode formation process P3.

[0027] Furthermore, as shown in Figure 3A, it is preferable to perform the cutting so that both ends of the channel groove 13 do not reach the edge of the wafer 10, leaving the side edge of the wafer 10 exposed. The drive wall 14 has a very narrow width in the second direction Y. Therefore, if the channel groove 13 is cut so that both ends reach the edge of the wafer 10, the drive wall 14 between the channel grooves 13 becomes prone to collapsing.

[0028] Furthermore, in the substrate manufacturing process P1, a thicker piezoelectric element substrate 12b may be used instead of the substrate 11, and in the channel groove formation process P2, the channel groove 13 may be cut from the thin piezoelectric element substrate 12a side to the middle of the thicker piezoelectric element substrate 12b. In this way, the drive wall 14, in which the polarization direction is opposite in the height direction, is formed, and at the same time, the portion of the substrate 11 is integrally formed with the piezoelectric element substrate 12b.

[0029] (Electrode formation process) Next, as electrode formation step P3, electrodes 15 are formed on the inner surface of the channel groove 13, as shown in Figure 4.

[0030] The electrode 15 is formed to apply a voltage to a piezoelectric element that causes a change in the volume of the channel. Methods for forming the electrode 15 include plating, vapor deposition, sputtering, and CVD (chemical vapor deposition) using a vacuum apparatus to form a metal film.

[0031] The metal used to form the electrode 15 can be nickel (Ni), cobalt (Co), copper (Cu), aluminum (Al), etc. From the standpoint of electrical resistance, Al or Cu are preferable, but Ni is preferred from the standpoint of corrosion resistance, strength, and cost. Alternatively, a laminated structure in which gold (Au) is further laminated on top of Al may be used.

[0032] Furthermore, the electrodes 15 must be independent for each channel groove 13. Therefore, as shown in Figure 4, it is necessary to prevent the formation of a metal coating on the upper end surface of the drive wall 14. For this reason, it is preferable to, for example, attach a dry film or form a resist film on the upper end surface of each drive wall 14 beforehand, and then form the metal coating. In this way, by removing the dry film or resist film after the metal coating has been formed, the electrodes 15 can be selectively formed only on the side surfaces of each drive wall 14 facing into the channel groove 13 and on the bottom surface of each channel groove 13.

[0033] (Capacity inspection process) Next, in the capacitance inspection step P4, the capacitance and resistance values ​​of the electrodes 15 in each channel groove 13 are inspected using a prober. If an electrode 15 that does not meet the specified electrical capacity or resistance value is detected at this stage, the corresponding part is discarded in the cutting process P7.

[0034] (Air vent groove formation process) Next, as the air relief groove formation step P5, as shown in Figure 5A, cutting is performed in the second direction Y to form air relief grooves 13b that penetrate the multiple channel grooves 13.

[0035] The air escape groove 13b is a passage for releasing air from the channel groove 13 to the outside of the channel groove 13 in the subsequent laminated substrate manufacturing process P6. Therefore, the air escape groove 13b is provided such that at least one end of the channel groove 13 communicates with the other end of the wafer 10. In particular, as shown in Figure 5A, it is preferable to provide the air escape groove 13b so that it communicates from one end to the other end of the wafer 10, as this allows air to escape in both directions.

[0036] The location where the air vent groove 13b is formed in the channel groove 13 is not particularly limited, but it is preferable to form it in the curved portion 13a, as shown in Figures 5A and 5B. In wafer 10, areas where air vent grooves 13b are formed cannot be used as head chips. Therefore, in the subsequent cutting process P7, it is necessary to cut the wafer 10 while avoiding the areas where air vent grooves 13b are formed. Thus, it is preferable to form the air vent grooves 13b in the curvatured portion 13a, which has a different volume from the channel grooves 13 and is originally a discarded area, because the discarded areas are grouped together, making it possible to form more head chips from wafer 10.

[0037] Furthermore, if a dicing blade is used in both the channel groove formation process P2 and the air vent groove formation process P5, the two processes may be performed consecutively for the purpose of simplifying the work. However, it is preferable to perform the electrode formation process P3 and the capacity inspection process P4 before the air vent groove formation process P5. This is because if the air vent groove 13b is formed before the electrode formation process P3, the electrode 15 will short-circuit, making it impossible to perform the capacity inspection process P4.

[0038] (Laminated substrate manufacturing process) Next, in the laminated substrate manufacturing process P6, a laminated substrate 20 is manufactured by stacking multiple wafers (for example, four wafers) that have channel grooves 13, air vent grooves 13b, and electrodes 15 formed on them.

[0039] Specifically, the second surface of a second substrate (wafer 10), which is a substrate that is bonded to the first surface of the first substrate (wafer 10) on which the channel groove 13 is formed, is laminated and bonded with an adhesive. Then, a cover substrate 16 is bonded to the first surface of the second substrate with an adhesive. Two such laminates, each consisting of two wafers 10 and one cover substrate 16, are prepared, and the cover substrates 16 of both laminates are bonded to each other with an adhesive to produce a laminated substrate 20. In other words, in this embodiment, the laminated substrate 20 is manufactured by joining together multiple laminates, which are laminated substrates composed of multiple substrates stacked together.

[0040] Figure 6A shows the laminated substrate 20 formed in this manner. In this configuration, among the laminates, wafer 10a is a first substrate to which another wafer 10 (wafer 10b) is bonded only to its first surface. In contrast, the other wafer 10b is a second substrate to which the first surface of the first substrate is bonded to its second surface, and is also a first substrate to which a cover substrate 16, which is a second substrate, is bonded to its first surface. In the following, the wafer 10 which is the first substrate will be referred to as "wafer 10a," and the wafer 10 which is both the first and second substrate will be referred to as "wafer 10b."

[0041] In this process, it is preferable to use the same substrate material as the piezoelectric material constituting the drive wall 14 for the cover substrate 16, after depolarization. By doing so, it is possible to suppress variations in velocity distribution and drive characteristics caused by differences in thermal expansion coefficients, due to the heat generated when the cover substrate 16 is heat-bonded and the heat generated when the droplet ejection head is driven after completion.

[0042] Furthermore, the number of wafers 10 is not limited to four. The number of wafers 10 can be arbitrarily changed according to the number of rows of head chips, and it can be six or any other number. Note that if the number of wafers 10 is four, the head chip will have a four-row configuration, and if it is six, the head chip will have a six-row configuration.

[0043] Furthermore, the method of stacking the wafers 10 and cover substrate 16 to form the laminated substrate 20 is not limited to the form shown in Figure 6A. For example, as shown in Figure 6B, a laminated substrate 20 may be formed by joining laminates in which the second surface of wafer 10b is joined to the first surface of wafer 10a, and then joining the cover substrate 16 to the first surface of the uppermost wafer 10b, where the second surface of wafer 10b is not joined.

[0044] Alternatively, as shown in Figure 6C, a laminated substrate 20 may be formed by stacking multiple laminates, each of which has its first surface facing the first surfaces of two wafers 10a and a cover substrate 16 bonded to the first surfaces.

[0045] Furthermore, while Figures 6A to 6C illustrate a case where a cover substrate 16 narrower in the first direction X than the channel groove 13 is bonded to the first substrate, the case is not limited to this. As shown in Figure 7, a cover substrate 16 with equal width in the first direction X may be bonded to the wafer 10.

[0046] Furthermore, it is preferable to perform a heating and pressing treatment after joining the individual substrates to create the laminated substrate 20. By performing the heating and pressing treatment, the bonding strength between the substrates can be further increased. In conventional inventions, when heating and pressurizing treatment is performed, the air in the channel groove 13 expands, causing particularly noticeable variations in the amount of adhesive overflow and forming fillets of uneven size. However, in this embodiment, an air vent groove 13b is provided in the channel groove 13, allowing the expanded air to escape, thus forming fillets of substantially uniform size.

[0047] (cutting process) Next, in the cutting process P7, as shown in Figure 8, a dicing blade or the like is used to perform a full cut (cut) at multiple cutting points D arranged at predetermined intervals along the longitudinal direction (first direction X) and the direction (second direction Y) of the channel groove 13, thereby cutting out multiple head chips with a channel length equal to a predetermined pitch P. As described above, in the cutting process P7, the laminated substrate 20 is cut in two parts: the part including the air vent groove 13b and the head chip part.

[0048] Of the cut surfaces of the head chip cut out by a dicing blade or the like, the first cut surface becomes the nozzle plate joining surface, to which a nozzle plate, which is a flat plate on which multiple nozzles are formed, is joined. The second cut surface becomes the wiring board joining surface, to which a wiring board that supplies power to the electrode 15 is joined.

[0049] Furthermore, in Figure 8, the pitch P of the channels of the cut-out head chips is made the same by setting the pitch P of multiple cutting sections D to the same value, but this is not the only option. In other words, by varying the spacing between the multiple cutting sections D, multiple types of head chips with different channel lengths can be cut from a single laminated substrate 20.

[0050] Alternatively, before the cutting process, a groove may be formed on the outside of the cutting area D, extending across all the channel grooves 13, so that the cutting debris generated during the cutting process is discharged through this groove. [Examples]

[0051] Next, the results of the evaluation of the head chip manufacturing method of the present invention will be described. The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0052] (Exam content) Head chips were prepared from a laminated substrate 20 formed by bonding wafers 10a and 10b, which have air vent grooves 13b in the channel grooves 13, with a cover substrate 16 that is narrower in the first direction X than the air vent grooves 13b, as shown in Figure 6A, and then subjected to heating and pressurizing treatment. Head chips were also prepared from wafers 10a and 10b, which do not have air vent grooves 13b in the channel grooves 13, with a cover substrate 16 that is narrower in the first direction X than the air vent grooves 13b, as shown in Figure 6A, and then subjected to heating and pressurizing treatment. These head chips were then mounted in an inkjet recording device, and for each channel, the AL at which the droplet ejection speed is maximized was measured when the drive pulse width was changed. Here, AL is 1 / 2 of the acoustic resonance period of the channel.

[0053] Figure 9A shows the measurement results for wafer 10b, the substrate on the side where the first surface is in contact with the cover substrate 16, in a four-row head chip configuration with air vent grooves 13b. Figure 9B shows the measurement results for wafer 10a, the substrate on the side where the first surface is in contact with the second surface of the first substrate, in a four-row head chip configuration with air vent grooves 13b. Figure 10A also shows the measurement results for wafer 10b in a four-row head chip configuration without air vent grooves 13b. Figure 10B also shows the measurement results for wafer 10a in a four-row head chip configuration without air vent grooves 13b.

[0054] (evaluation) As can be seen from comparing Figure 9A and Figure 10A, or Figure 9B and Figure 10B, forming an air vent groove 13b in the channel groove 13 makes it possible to stabilize the discharge characteristics.

[0055] This effect is particularly evident when comparing Figure 9B and Figure 10B. In Figure 10B, the entire surface of the channel groove 13 is covered by the wafer 10b, and there is no escape route for the air within the channel groove 13. As a result, variations occur in the amount of adhesive flowing out when bonding wafer 10b to wafer 10a, forming fillets of uneven size in each channel. These uneven fillets cause variations in the volume of the channels, leading to unstable discharge characteristics. On the other hand, in Figure 9B, although the channel groove 13 is covered by the wafer 10b, the air escape groove 13b serves as an escape route for the air within the channel groove 13. As a result, the amount of adhesive flowing out becomes approximately constant, more uniform fillets are formed, variations in the volume of each channel are less likely to occur, and discharge characteristics become more stable.

[0056] On the other hand, comparing Figure 9A and Figure 10A, there is little effect in stabilizing the ejection characteristics. This is because the head chip in Figure 10A has a cover substrate 16 that is narrow in the first direction X, and the channel groove 13 has an opening. Therefore, it is thought that the opening served as an escape route for the air in the channel groove 13 even without providing an air escape groove 13b.

[0057] Therefore, when a narrow cover substrate 16 in the first direction X is bonded to the first surface of a wafer 10b, and the channel groove 13 has an opening, it is not necessary to form an air vent groove 13b on the wafer 10b. However, if an air vent groove 13b is formed on the wafer 10b, air will escape not only from the opening of the channel groove 13 but also from the air vent groove 13b, resulting in more stable ejection characteristics. For this reason, even when a narrow cover substrate 16 in the first direction X is bonded to the first surface of the wafer 10b, it is preferable to form an air vent groove 13b on the channel groove 13.

[0058] [Technical Effects of the First Embodiment] As described above, the method for manufacturing a head chip according to this embodiment includes an air vent groove forming step P5 in which an air vent groove 13b is formed on the first surface of a first substrate having a plurality of channel grooves 13 extending in a first direction X, and which extends in a second direction Y substantially perpendicular to the first direction X and penetrates the plurality of channel grooves 13, and a laminated substrate manufacturing step P6 in which a second substrate is bonded to the first surface having the air vent groove 13b with an adhesive to form a laminated substrate 20, wherein the air vent groove forming step P5 forms the air vent groove 13b such that at least one end communicates with the edge of the first substrate. This configuration allows for a nearly uniform amount of adhesive overflow during the P6 manufacturing process of the laminated substrate, i.e., the size of the fillets formed within each channel, thus reducing variations in the volume of each channel. As a result, stable ejection performance is achieved when the head chip is mounted on a droplet ejection device.

[0059] Furthermore, in the manufacturing method of the head chip according to this embodiment, the air vent groove forming step P5 forms an air vent groove 13b at the end of the channel groove 13 in the first direction X. According to this configuration, more head chips can be formed from a single laminated substrate 20.

[0060] Furthermore, in the manufacturing method of the head chip according to this embodiment, the air relief groove forming step P5 forms an air relief groove 13b in the curved portion 13a that is formed in a curved shape at the end of the channel groove 13 in the first direction X. By forming a curved portion 13a at the end of the channel groove 13, the formation of the electrode 15 becomes easier. In addition, since the curved portion 13a and the air vent groove 13b, which are waste points in the head chip manufacturing process, are combined into one unit, it becomes possible to form more head chips from the laminated substrate 20.

[0061] Furthermore, the manufacturing method of the head chip according to this embodiment includes an electrode formation step P3 in which electrodes 15 are formed in the channel groove 13, and a capacitance inspection step P4 in which the electrical capacitance of the electrodes 15 is inspected, and the electrode formation step P3 and the capacitance inspection step P4 are performed before the air vent groove formation step P5. This configuration prevents the capacity inspection process P4 from being prevented by the air vent groove 13b, making it possible to manufacture head tips with higher precision.

[0062] Furthermore, in the method for manufacturing a head chip according to this embodiment, the laminated substrate manufacturing step P6 involves applying heat treatment and pressure treatment to the first substrate and the second substrate, which are joined together with an adhesive, to join the second substrate to the first substrate. This configuration allows for a stronger bond between the substrates.

[0063] Furthermore, the method for manufacturing the head chip according to this embodiment includes a cutting step P7 in which the laminated substrate 20 is cut into a portion including the air vent groove 13b and a head chip portion. According to this configuration, by including the air relief groove 13b, it is possible to prevent the formation of a head tip with channels of different volumes.

[0064] Furthermore, in the method for manufacturing the head chip according to this embodiment, the laminated substrate manufacturing step involves forming a fillet made of adhesive in the channel groove 13. This configuration makes it possible to manufacture head chips in which the substrates are sufficiently bonded to each other.

[0065] [Second Embodiment] The method for manufacturing a head chip according to the second embodiment will be described below. Note that the description of parts identical to those for manufacturing a head chip according to the first embodiment will be omitted.

[0066] (Air vent groove formation process) The main difference between the head chip manufacturing method according to the first embodiment and the head chip manufacturing method according to the second embodiment is the air vent groove formation step P5. Specifically, in the air vent groove formation step P5 according to the second embodiment, as shown in Figure 11, an air vent groove 13b is formed on the second surface of the wafer 10b or cover substrate 16, which is the second substrate, and is bonded to the first surface of the wafer 10a or wafer 10b, which is the first substrate, so as to be in contact with a plurality of channel grooves 13.

[0067] [Technical Effects of the Second Embodiment] In the head chip manufacturing method according to the first embodiment, as described above, when the electrode formation step P3 and the capacitance inspection step P4 are performed, the air vent groove formation step P5 must be performed after these steps. However, in the head chip manufacturing method according to the second embodiment, the air vent groove 13b is not formed in the channel groove 13. Therefore, the air vent groove formation step P5 can be performed at any timing before the laminated substrate manufacturing step P6.

[0068] In the first embodiment, it was preferred to form an air vent groove 13b in the curved portion 13a. However, in this embodiment as well, the same effect can be obtained by forming the air vent groove 13b in a location that comes into contact with the curved portion 13a during the laminated substrate manufacturing process P6.

[0069] Although the present invention has been described in detail based on embodiments of the present invention, it is important to note that the present invention is not limited to the embodiments described above, and various modifications are possible, including the scope of the invention as described in the claims and its equivalents. [Explanation of symbols]

[0070] 10, 10a, 10b wafers (first substrate, second substrate) 13 channel grooves 13a Curvature part 13b Air vent groove 15 electrodes 16 Cover board 20 Multilayer substrates P3 Electrode formation process P4 Capacity Inspection Process P5 Air vent groove formation process P6 Multilayer Substrate Manufacturing Process P7 Cutting process X first direction Y Second direction

Claims

1. A method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The air vent groove forming step is a method for manufacturing a head chip in which the air vent groove is formed in a curved portion formed in a curved shape at the end of the channel groove in the first direction, such that at least one end communicates with the end of the first substrate.

2. A method for manufacturing a head chip, An electrode forming step of forming electrodes in the channel grooves of a first substrate having a plurality of channel grooves extending in a first direction formed on its first surface, A capacitance testing step for testing the electrical capacitance of the electrode, An air vent groove forming step is to form an air vent groove on the first surface of the first substrate, extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The air vent groove forming step involves forming the air vent groove such that at least one end communicates with the end of the first substrate. A method for manufacturing a head chip, wherein the electrode formation step and the capacity inspection step are performed before the air vent groove formation step.

3. A method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, A laminated substrate manufacturing process involves bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The process includes a cutting step of dividing the laminated substrate into a portion including the air vent groove and a head chip portion, The air vent groove forming step is a method for manufacturing a head chip in which the air vent groove is formed such that at least one end communicates with the edge of the first substrate.

4. A method for manufacturing a head chip, An air vent groove forming step is performed on the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, and an air vent groove is formed extending in a second direction substantially perpendicular to the first direction and penetrating the plurality of channel grooves, The process includes a laminated substrate manufacturing step of bonding a second substrate to the first surface on which the air vent groove is formed using an adhesive to form a laminated substrate, The air vent groove forming step involves forming the air vent groove such that at least one end communicates with the end of the first substrate. The aforementioned laminated substrate manufacturing process is a method for manufacturing a head chip, which involves bonding a plurality of laminated substrates, each formed by bonding a first substrate and a second substrate, together with an adhesive.

5. A method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, and the air vent groove abuts against a curved portion formed in a curved shape at the end of the channel groove of the first substrate in the first direction. The aforementioned laminated substrate manufacturing process is a method for manufacturing a head chip, which involves joining the first substrate and the second substrate such that the plurality of channel grooves and the air vent grooves are in contact with each other.

6. A method for manufacturing a head chip, An electrode forming step of forming electrodes in the channel grooves of a first substrate having a plurality of channel grooves extending in a first direction formed on its first surface, A capacitance testing step for testing the electrical capacitance of the electrode, A laminated substrate manufacturing process in which the second surface of a second substrate is bonded to the first surface of the first substrate with an adhesive to form a laminated substrate, The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The aforementioned laminated substrate manufacturing process is a method for manufacturing a head chip, which involves joining the first substrate and the second substrate such that the plurality of channel grooves and the air vent grooves are in contact with each other.

7. The method for manufacturing a head chip according to claim 6, wherein the electrode formation step and the capacity inspection step are performed before the air vent groove formation step.

8. A method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; An air vent groove forming step is performed on the second surface of the second substrate, forming an air vent groove extending in a second direction substantially perpendicular to the first direction, The process includes a cutting step of dividing the laminated substrate into a portion including the air vent groove and a head chip portion, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The aforementioned laminated substrate manufacturing process is a method for manufacturing a head chip, which involves joining the first substrate and the second substrate such that the plurality of channel grooves and the air vent grooves are in contact with each other.

9. A method for manufacturing a head chip, A laminated substrate manufacturing process comprising: bonding the second surface of a second substrate to the first surface of a first substrate, which has a plurality of channel grooves extending in a first direction formed on its first surface, using an adhesive to form a laminated substrate; The process includes an air vent groove forming step, in which an air vent groove is formed on the second surface of the second substrate in a second direction substantially perpendicular to the first direction, The air vent groove formation step is a step performed before the laminated substrate manufacturing step, The air vent groove is formed such that at least one end communicates with the end of the second substrate, The aforementioned laminated substrate manufacturing process is a method for manufacturing a head chip, comprising joining multiple laminated substrates, each formed by joining a first substrate and a second substrate, with an adhesive so that the multiple channel grooves and the air vent grooves are in contact with each other.

10. The method for manufacturing a head chip according to any one of claims 1 to 9, wherein the laminated substrate manufacturing step involves bonding the second substrate to the first substrate so as to cover the entire surface of the channel groove.

11. The method for manufacturing a head chip according to any one of claims 1 to 9, wherein the laminated substrate manufacturing step involves bonding the second substrate to the first substrate by applying heat treatment and pressure treatment to the first substrate and the second substrate which are joined together with an adhesive.

12. The method for manufacturing a head chip according to any one of claims 1 to 9, wherein the laminated substrate manufacturing step involves forming a fillet made of adhesive in the channel groove.

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