JP2009234091A - Method for manufacturing inkjet recording head - Google Patents

Abstract

A method of manufacturing an ink jet recording head capable of preventing creeping discharge and improving reliability is provided.
A predetermined surface for forming a plurality of piezoelectric actuators on one surface of a piezoelectric substrate having a predetermined thickness greater than that required for a piezoelectric actuator and having electrodes formed on one surface. A process for processing into a shape (steps 102 to 106), an adhesive for bonding one surface of the piezoelectric substrate and a surface of the pressure chamber forming substrate on which the electrode is formed on the side on which the electrode is formed with an adhesive A step (steps 108 and 110), a polishing step of polishing the other surface of the piezoelectric substrate until the predetermined shape appears (step 112), and electrode formation for forming an upper electrode on the other surface of the piezoelectric substrate And (steps 116 and 118).
[Selection] Figure 1

Description

  The present invention relates to an ink jet recording head manufacturing method, and more particularly, to an ink jet recording head manufacturing method including a bend type (unimorph structure) piezoelectric actuator.

  Conventionally, as an inkjet recording head including a bend type piezoelectric actuator, a piezoelectric substrate is made into a thin film, and then a pressure chamber forming substrate on which a pressure chamber is formed is bonded to the piezoelectric substrate with an adhesive, or unprocessed In general, the piezoelectric substrate and the pressure chamber forming substrate are bonded to each other with an adhesive, and the piezoelectric substrate is then thinned by, for example, polishing to process the piezoelectric substrate into a shape corresponding to the pressure chamber.

  However, with the former method, it is difficult to handle the thin film piezoelectric substrate and it is easily damaged. For this reason, there existed a problem that thin film formation was difficult and there existed a limit in density increase.

  Further, the latter method has a problem that when the raw piezoelectric substrate and the pressure chamber forming substrate are bonded to each other, there is no escape route for the adhesive, and the adhesion stability is lacking.

  In addition, when the piezoelectric substrate is processed into a shape corresponding to the pressure chamber after being thinned, masking is performed on the surface opposite to the adhesive surface with the pressure chamber forming substrate, so that the surface on the adhesive surface side is processed. There was also a problem that the dimensional accuracy deteriorated and the variation in displacement of each piezoelectric actuator increased.

  Furthermore, although the piezoelectric substrate can be thinned, the processing surface of the piezoelectric substrate, that is, the surface opposite to the adhesive surface with the pressure chamber forming substrate is exposed, and this surface corresponds to the pressure chamber. In the case of processing into a shape, there is a possibility that it may be destroyed by creeping discharge by thinning it, and there is a problem that it is necessary to take measures to prevent this.

Patent Document 1 discloses a method in which a thin piezoelectric substrate is temporarily attached to a support substrate, processed into a shape corresponding to a pressure chamber, and bonded to the pressure chamber forming substrate, and then the support substrate is peeled off. ing.
JP 2003-48323 A

  However, in the method described in Patent Document 1, there is a high possibility that breakage or cracks occur in the step of temporarily attaching a thin piezoelectric substrate to the support substrate or the step of peeling the support substrate from the pressure chamber forming substrate. There was a problem. In addition, since it is necessary to thin the piezoelectric plate in advance, there is a problem that a large size piezoelectric substrate cannot be used.

  SUMMARY An advantage of some aspects of the invention is that it provides a method of manufacturing an ink jet recording head that can prevent creeping discharge and improve reliability.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that the one surface of the piezoelectric substrate having a predetermined thickness more than a thickness required as a piezoelectric actuator and having an electrode formed on one surface, A processing step of processing into a predetermined shape for forming a plurality of the piezoelectric actuators, and bonding one surface of the piezoelectric substrate to a surface of the pressure chamber forming substrate on which the electrodes are formed on the side on which the electrodes are formed A bonding step of bonding with an agent, a polishing step of polishing the other surface of the piezoelectric substrate until the predetermined shape appears, and an electrode forming step of forming an upper electrode on the other surface of the piezoelectric substrate. It is characterized by that.

  According to the present invention, an ink jet recording head is manufactured by processing a piezoelectric substrate having a predetermined thickness greater than that required for a piezoelectric actuator and bonding it to a pressure chamber forming substrate, and then polishing the piezoelectric substrate. It is possible to prevent the piezoelectric substrate from being damaged when the piezoelectric substrate is gripped in the manufacturing process.

  In addition, the piezoelectric substrate can be easily thinned, and the piezoelectric actuator can be increased in size and density.

  Also, since the bonding surface side of the piezoelectric substrate with the pressure chamber forming substrate is processed, compared to the case of processing by masking the surface opposite to the bonding surface with the pressure chamber forming substrate as in the past, It can prevent that the dimensional accuracy by the side of an adhesion surface deteriorates. Thereby, it is possible to prevent the variation in displacement of each piezoelectric actuator from becoming large. Therefore, a highly reliable ink jet recording head can be obtained.

  In addition, since the pressure chamber forming substrate is bonded after processing the bonding surface side of the piezoelectric substrate with the pressure chamber forming substrate, excess adhesive protrudes into the grooves formed on the processing surface of the piezoelectric substrate, and then onto the piezoelectric substrate. Since bonding is performed so as to cover the formed electrode, the piezoelectric element and the electrode on the pressure chamber forming substrate side can be insulated, and creeping discharge can be prevented. Therefore, a highly reliable ink jet recording head can be obtained.

  In addition, as described in claim 2, the processing step is a step of processing the piezoelectric substrate bonded to a support substrate into the predetermined shape, and after the bonding step and before the polishing step, You may make it further include the peeling process which peels the said support substrate from the said piezoelectric substrate. Thereby, a thin piezoelectric substrate can be used compared with the case where it is not bonded to the support substrate, and the polishing amount of the piezoelectric substrate after the support substrate is peeled off can be greatly reduced.

  According to the present invention, creeping discharge can be prevented, and the reliability can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First embodiment)

  In the present embodiment, a method for manufacturing an ink jet recording head used in an ink jet recording apparatus that records an image by ejecting ink onto a recording medium such as paper according to the image will be described. The ink jet recording head has a plurality of nozzles for ejecting ink, and a piezoelectric actuator is formed corresponding to each nozzle.

  FIG. 1 is a flowchart showing the flow of the manufacturing process of the ink jet recording head, and FIGS. 2 and 3 are cross-sectional views showing the manufacturing process of the ink jet recording head.

  First, as shown in FIG. 2A, a piezoelectric substrate 10 having a predetermined thickness d1 is prepared. The thickness d1 is equal to or greater than the thickness d2 required for the piezoelectric actuator, and has a thickness that does not cause damage when the piezoelectric substrate 10 is gripped in the manufacturing process. In the present embodiment, as an example, d1 is about 3 mm and d2 is about 15 μm.

  As shown in FIG. 1, first, in step 102, an electrode 12 is formed on one surface of the piezoelectric substrate 10 as shown in FIG. As a method for forming the electrode 12, various known methods such as resistance heating vapor deposition, electron beam (EB) vapor deposition, and sputtering can be used.

  In step 104, photolithography is performed to form a groove on the surface of the piezoelectric substrate 10 on which the electrode 12 is formed. That is, as shown in FIG. 2C, a photoresist 14 is applied on the electrode 12, masked so that the photoresist 14 remains in a region other than the region 16 where a groove is to be formed, pattern exposure is performed, and then development is performed. Process. As a result, the photoresist 14 remains in a region other than the region 16 where the groove is to be formed. Note that the shape of the region where the photoresist 14 is left is a shape corresponding to a pressure chamber formed on a pressure chamber forming substrate, which will be described later, and a predetermined shape for forming a plurality of piezoelectric actuators.

  In step 106, first, etching, for example, reactive ion etching (RIE) is performed. As a result, as shown in FIG. 2D, regions other than the photoresist 14 are etched to form grooves 18. That is, the surface of the piezoelectric substrate 10 on which the electrodes 12 are formed is processed into a predetermined shape. At this time, etching is performed so that the depth of the groove 18 is equal to or greater than a predetermined depth d3.

  This d3 is not less than the thickness d2 required for the piezoelectric actuator described above. For example, when d2 is about 15 μm, d3 is about 16 to 20 μm. This is because when the piezoelectric substrate 10 is polished from the other surface until the thickness of the piezoelectric substrate 10 reaches d2, as described later, the predetermined shape appears on the other surface.

  The groove 18 may be formed not only by reactive ion etching but also by sandblasting. Further, as shown in FIG. 2D, the groove 18 has a tapered shape with a wide opening and a narrow bottom.

  After etching as described above, the remaining photoresist 14 is removed with a solvent or the like.

  In step 108, as shown in FIG. 2E, an adhesive 24 is applied on the electrode 20 of the pressure chamber forming substrate 22 having the electrode 20 formed on one surface by a method such as spin coating, for example. Apply with. The coating thickness of the adhesive 24 is preferably at least equal to or greater than the thickness of the electrode 12 formed on the piezoelectric substrate 10 and is, for example, about 1 μm.

  A plurality of pressure chambers 26 are formed on the pressure chamber forming substrate 22, and nozzles 28 for ejecting ink are provided below the pressure chambers 26. The electrode 20 is an electrode that functions as a common electrode.

  In step 110, as shown in FIG. 2F, the piezoelectric substrate 10 and the pressure chamber forming substrate 22 are bonded. At this time, since the coating thickness of the adhesive 24 is at least equal to or greater than the thickness of the electrode 12 formed on the piezoelectric substrate 10, excess adhesive 24 </ b> A protrudes from the side surface of the groove 18.

  As described above, the groove 18 functions as a space for releasing excess adhesive 24 </ b> A, and the protruding adhesive 24 </ b> A is bonded to the piezoelectric substrate 10 so as to cover the electrode 12. Thereby, the side surface of the groove 18 formed in the piezoelectric substrate 10 can be insulated from the electrode 20 on the pressure chamber forming substrate 22 side, and creeping discharge can be prevented.

  In step 112, as shown in FIG. 3A, the surface of the piezoelectric substrate 10 opposite to the adhesive surface with the pressure chamber forming substrate 22 is polished until the thickness of the piezoelectric substrate 10 becomes d2. As a result, the predetermined shape appears on the surface of the piezoelectric substrate 10 opposite to the adhesive surface with the pressure chamber forming substrate 22, and the piezoelectric element 10A is formed.

  In step 114, photolithography is performed to form an upper electrode. That is, as shown in FIG. 3B, the photoresist 30 is coated on the polishing side surface of the piezoelectric substrate 10 and masked so that the photoresist 30 remains in a region other than the region where the upper electrode 32 is to be formed. Pattern exposure is performed, followed by development processing. As a result, the photoresist 30 remains in a region other than the region where the upper electrode 32 is to be formed.

  In step 116, as shown in FIG. 3B, the upper electrode 32 is formed in a region other than the region where the photoresist 30 remains.

  In step 118, as shown in FIG. 3C, the photoresist 30 is removed with a solvent or the like to complete the ink jet recording head.

  FIG. 4 shows an example of a plan view of FIG. 3C viewed from the upper electrode 32 side. FIG. 3C is a cross-sectional view taken along the line AA in FIG. A broken line 34 shown in FIG. 4 indicates the lower side of the piezoelectric element 10A, that is, the edge on the pressure chamber forming substrate 22 side. In FIG. 4, the piezoelectric element 10A has a hexagonal shape, that is, the shape of the pressure chamber 26 on the piezoelectric element 10A side is a hexagonal shape. However, the shape of the piezoelectric element 10A and the pressure chamber 26 on the piezoelectric element 10A side is not limited thereto. It is not something that can be done.

  As described above, in the present embodiment, a piezoelectric substrate having a thickness greater than that required for the piezoelectric actuator and not damaged when the piezoelectric substrate 10 is gripped in the manufacturing process is processed. Since the ink jet recording head is manufactured by adhering to the pressure chamber forming substrate 22 and then polishing the piezoelectric substrate 10, the piezoelectric substrate 10 is prevented from being damaged when the piezoelectric substrate 10 is gripped in the manufacturing process. Can do. In addition, the piezoelectric substrate 10 can be easily thinned, and the piezoelectric actuator can be increased in size and density.

  In addition, since the bonding surface side of the piezoelectric substrate 10 with the pressure chamber forming substrate 22 is processed into a shape corresponding to the pressure chamber 26 of the pressure chamber forming substrate 22, it is opposite to the bonding surface with the pressure chamber forming substrate as in the prior art. Compared to the case where the side surface is masked and processed, it is possible to prevent the dimensional accuracy on the bonding surface side from deteriorating. This is because when the surface opposite to the adhesive surface with the pressure chamber forming substrate is processed as in the prior art, the position of the bottom portion of the processed groove varies, and as a result, the dimensional accuracy of each piezoelectric element varies. Because. On the other hand, in this embodiment, since the bonding surface side of the piezoelectric substrate 10 with the pressure chamber forming substrate 22 is processed, it is possible to prevent the dimensional accuracy of each piezoelectric element from varying. An increase in variation in displacement can be prevented. Therefore, a highly reliable ink jet recording head can be obtained.

  In addition, since the pressure chamber forming substrate 22 is bonded after the bonding surface side of the piezoelectric substrate 10 with the pressure chamber forming substrate 22 is processed, excess adhesive 24A protrudes into the groove 18 on the piezoelectric substrate 10 side. Since bonding is performed so as to cover the electrode 12 formed thereon, the piezoelectric element 10A and the electrode 20 on the pressure chamber forming substrate 22 side can be insulated, and creeping discharge can be prevented. Therefore, a highly reliable ink jet recording head can be obtained.

  (Second Embodiment)

  Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as 1st Embodiment, and the detailed description is abbreviate | omitted.

  FIG. 5 is a flowchart showing the flow of the manufacturing process of the ink jet recording head according to this embodiment, and FIG. 6 is a cross-sectional view showing the manufacturing process of the ink jet recording head.

  The manufacturing process of this embodiment is different from the manufacturing process described in the first embodiment in that a piezoelectric substrate 10 to which a support substrate 40 is bonded is used as shown in FIG. As the support substrate, for example, a member that can be peeled off from the piezoelectric substrate 10 by applying heat, such as a thermal foam tape, or a tape that can be peeled off from the piezoelectric substrate 10 by irradiating ultraviolet rays can be used. The present invention is not limited to this as long as it can be peeled off from the substrate 10.

  In this case, the total thickness of the piezoelectric substrate 10 and the support substrate 40 has a thickness that does not cause damage when gripped in the manufacturing process, and the thickness d1 of the piezoelectric substrate 10 is required as a piezoelectric actuator. The thickness is equal to or greater than the thickness d2, and has a thickness (for example, about 1 mm) that is not damaged when the support substrate 40 is peeled off from the piezoelectric substrate 10 in the manufacturing process.

  Accordingly, as shown in FIGS. 6A to 6F, steps 102 to 110 in FIG. 5 are executed in a state where the support substrate 40 is bonded to the piezoelectric substrate 10. This is the same as steps 102 to 110 in FIG.

  In step 111 of FIG. 5, the support substrate 40 is peeled from the piezoelectric substrate 10 as shown in FIG.

  Subsequent steps 114 to 116 are the same as steps 114 to 116 in FIG. 1, but in the polishing process in step 112, the thickness of the piezoelectric substrate 10 is already thinner than that in FIG. The amount can be greatly reduced.

  In each of the above embodiments, the case where the pressure chamber forming substrate 22 in which the pressure chamber 26 has already been formed is bonded to the piezoelectric substrate 10 is described. However, the present invention is not limited to this, and the pressure chamber forming substrate in which the pressure chamber 26 is not formed. The pressure chamber 26 may be formed after bonding the piezoelectric substrate 10 to the piezoelectric substrate 10.

3 is a flowchart showing a flow of manufacturing steps of the ink jet recording head according to the first embodiment. It is sectional drawing which shows the manufacturing process of the inkjet recording head which concerns on 1st Embodiment. It is sectional drawing which shows the manufacturing process of the inkjet recording head which concerns on 1st Embodiment. It is a top view of an inkjet recording head. It is a flowchart which shows the flow of the manufacturing process of the inkjet recording head which concerns on 2nd Embodiment. It is sectional drawing which shows the manufacturing process of the inkjet recording head which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric substrate 10A Piezoelectric element 12 Electrode 14 Photoresist 18 Groove 20 Electrode 22 Pressure chamber forming substrate 24, 24A Adhesive 26 Pressure chamber 28 Nozzle 30 Photoresist 32 Upper electrode 40 Support substrate

Claims (2)

The one surface of the piezoelectric substrate having a predetermined thickness greater than that required for the piezoelectric actuator and having electrodes formed on one surface is processed into a predetermined shape for forming the plurality of piezoelectric actuators. Processing steps,
A bonding step of bonding one surface of the piezoelectric substrate and a surface of the pressure chamber forming substrate on which the electrode is formed on the side on which the electrode is formed with an adhesive;
A polishing step of polishing the other surface of the piezoelectric substrate until the predetermined shape appears;
Forming an upper electrode on the other surface of the piezoelectric substrate; and
A method for manufacturing an ink jet recording head comprising: The processing step is a step of processing the piezoelectric substrate bonded to a support substrate into the predetermined shape,
The method of manufacturing an ink jet recording head according to claim 1, further comprising a peeling step of peeling the support substrate from the piezoelectric substrate after the bonding step and before the polishing step.

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