JP2008073929A - Process for fabricating silicon device and process for manufacturing liquid ejection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for fabricating a silicon device in which the yield can be enhanced by preventing production of foreign substances in the fabrication process, and to provide a process for manufacturing a liquid ejection head. <P>SOLUTION: The process for fabricating a silicon device having a silicon substrate processed to have a predetermined shape by etching comprises a step for bonding a bonding substrate 130 having a diameter larger than that of a silicon wafer 110 having a chamfered part 111 on the periphery to the silicon wafer, a step for thinning the silicon wafer to which the bonding substrate is bonded to have a predetermined thickness, a step for forming a protective film 150 having an etching resistant layer composed of an etching resistant material at least on the surface layer on the bonding substrate to cover the chamfered part of the silicon wafer, a step for etching the silicon wafer to have a predetermined shape, and a step for dividing the silicon wafer into a plurality of silicon substrates. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a silicon device having a silicon substrate obtained by dividing a silicon wafer formed into a predetermined shape by etching into a plurality of parts, and in particular, includes a silicon substrate having a pressure generation chamber communicating with a nozzle opening for discharging droplets. The present invention is suitable for application to a method for manufacturing a liquid jet head including a flow path forming substrate.

  As an ink jet recording head which is a typical example of a liquid ejecting head, for example, a flow path forming substrate formed of a silicon substrate in which a pressure generating chamber communicating with a nozzle opening is formed, and one surface side of the flow path forming substrate And a sealing substrate (protective substrate) having a piezoelectric element holding portion that is bonded to the surface of the flow path forming substrate on the piezoelectric element side and seals the piezoelectric element (for example, Patent Document 1).

  As a manufacturing method of this ink jet recording head, for example, as described in Patent Document 1, first, a piezoelectric element is provided on one surface of a silicon wafer on which a plurality of flow path forming substrates are integrally formed via a vibration plate. Form. Then, a sealing substrate forming material serving as a sealing substrate is bonded to the silicon wafer, and the silicon wafer is wet-etched with an alkaline solution in a state where the sealing substrate forming material is bonded to form a pressure generating chamber or the like. Then, an ink jet recording head is manufactured by dividing the silicon wafer into a predetermined chip size.

  Here, as described in Patent Document 1, generally, a chamfered surface (chamfered portion) is formed on the peripheral portion of the silicon wafer on which a plurality of flow path forming substrates are integrally formed. There are many cases. When the piezoelectric element is formed on the silicon wafer via the vibration plate, a film constituting the vibration plate or the piezoelectric element is also formed on the chamfered surface. The film formed on the chamfered surface has lower adhesion and is more easily peeled off than the film formed on the other region of the silicon wafer. For this reason, when a pressure generation chamber or the like is formed by etching a silicon wafer, the film on the chamfered surface is peeled off to become a foreign matter, and the foreign matter adheres to the pressure generation chamber or the like, resulting in an initial failure such as nozzle clogging. There is a problem that occurs. That is, there is a problem that the yield is poor.

  With recent miniaturization, a relatively thin silicon substrate has been used as a flow path forming substrate. Then, as a method of manufacturing an ink jet recording head having such a relatively thin flow path forming substrate, for example, after a protective substrate wafer is bonded to a flow path forming substrate wafer (silicon wafer), a flow path is formed. There is a method of processing a substrate wafer into a predetermined thickness and forming a pressure generation chamber or the like by etching (see, for example, Patent Document 2).

JP 2003-266394 A JP 2004-82722 A

  As described above, a chamfered portion (chamfered surface) is generally formed at the peripheral edge portion of the silicon wafer (channel-forming substrate wafer). If the thickness of the silicon wafer having such a chamfered portion is processed relatively thin as described in Patent Document 2, for example, the thickness of the silicon wafer at the peripheral portion becomes extremely thin. In addition to the problem that the film is peeled off, there is a problem that cracks, chips, etc. occur at the peripheral edge of the silicon wafer. That is, there is a problem that a part of the peripheral portion of the silicon wafer is lost and becomes a foreign substance, which causes the initial failure as in the case of the film peeled off from the chamfered surface.

  Such a problem exists not only in a manufacturing method of a liquid jet head such as an ink jet recording head but also in a manufacturing method of various silicon devices represented by the liquid jet head.

  The present invention has been made in view of such circumstances, and provides a method for manufacturing a silicon device and a method for manufacturing a liquid jet head that can prevent the generation of foreign matters in the manufacturing process and improve the yield. With the goal.

A first aspect of the present invention that solves the above problems is a method of manufacturing a silicon device having a silicon substrate processed into a predetermined shape by etching, and a silicon wafer having a chamfered portion at a peripheral portion is formed on the silicon wafer. A bonding step of bonding a large-diameter bonding substrate, a thinning step of processing the silicon wafer to which the bonding substrate is bonded to a predetermined thickness, and an etching resistant layer made of a material having etching resistance at least on the surface layer A protective film forming step of forming a protective film on the bonding substrate so as to cover a chamfered portion of the silicon wafer, an etching step of etching the silicon wafer into a predetermined shape, and a plurality of the silicon wafers And a dividing step for dividing the silicon substrate.
In the first aspect, it is possible to prevent the peripheral edge of the silicon wafer from being cracked or chipped. Thereby, the generation | occurrence | production of the defect by the fragment | piece (foreign material) from which a part of silicon wafer was missing adhering to a silicon substrate can be prevented. In addition, since the silicon wafer is thinned, cracking and chipping due to the outer peripheral contact of the silicon wafer can be suppressed when the bonded substrate has a larger diameter than the silicon wafer.

The second aspect of the present invention is characterized in that a laminated film composed of at least one thin film is formed on the surface of the silicon wafer on the side to which the bonding substrate is bonded. It exists in the manufacturing method of a silicon device.
In such a second aspect, the protective film prevents the laminated film formed on the chamfered portion from being peeled off along with the occurrence of cracks and chips in the silicon wafer.

According to a third aspect of the present invention, there is provided the silicon device manufacturing method according to claim 1, wherein the thinning step is included before the protective film forming step.
In the third aspect, since there is a concern that the protective film is peeled off when the silicon wafer is thinned, the protective film is preferably formed after the thinning step.

According to a fourth aspect of the present invention, in the etching method, the silicon wafer is formed into a predetermined shape by wet etching using an alkaline solution. It is in.
In the fourth aspect, wet etching is more reliable than dry etching, and the above-described problems such as cracking and chipping of the silicon wafer that are likely to occur in the etching process can be reliably prevented.

According to a fifth aspect of the present invention, there is provided the silicon device manufacturing method according to the fourth aspect, wherein the etching resistant layer is made of gold (Au).
In the fifth aspect, when the silicon wafer is wet etched, the protective film is not etched by the etchant. Therefore, problems such as the occurrence of cracks and chipping of the silicon wafer described above can be prevented more reliably.

According to a sixth aspect of the present invention, there is provided the silicon device manufacturing method according to the fifth aspect, wherein the protective film is composed only of the etching-resistant layer, and the protective film is formed by plating.
In the sixth aspect, when the silicon wafer is wet-etched, it is possible to more reliably prevent the problem such as the above-described cracking or chipping of the silicon wafer caused by etching the protective film with the etching solution. . Further, by forming a protective film by plating, the protective film can be formed relatively easily so as to cover the chamfered portion of the silicon wafer including a recess that is likely to be formed at the boundary between the silicon wafer and the bonding substrate. be able to.

According to a seventh aspect of the present invention, there is provided a flow path forming substrate in which a liquid flow path including a pressure generating chamber communicating with a nozzle opening for ejecting liquid is formed, and provided on one side of the flow path forming substrate. A method for manufacturing a liquid jet head, comprising: a pressure generating element that applies pressure to a pressure generating chamber; and a protective substrate that is bonded to the one surface side of the flow path forming substrate. A step of forming the pressure generating element on one surface of a wafer for a flow path forming substrate formed of a silicon wafer, wherein a plurality of the flow path forming substrates are integrally formed, and the flow path forming substrate wafer and the protective substrate; Bonding a plurality of integrally formed protective substrate wafers, a thinning step of processing the flow path forming substrate wafer bonded with the bonded substrate to a predetermined thickness, and at least resisting the surface layer. Is it an etching material? Forming a protective film having an etching resistant layer on the surface of the protective substrate wafer to be bonded to the flow path forming substrate wafer so as to cover the chamfered portion of the flow path forming substrate wafer; A method of manufacturing a liquid jet head, comprising: etching a forming substrate wafer to form the liquid flow path; and dividing the flow path forming substrate wafer and the protective substrate wafer. is there.
In the seventh aspect, there is a problem that the peripheral edge of the flow path forming substrate wafer is cracked or chipped, or a film (for example, a film constituting a piezoelectric element) formed on the chamfered part is peeled off. Can be prevented. As a result, it is possible to prevent a defective discharge from occurring due to a part of the missing flow path forming substrate wafer or a foreign matter such as a film peeled off from the chamfered portion adhering to the liquid flow path such as the pressure generating chamber. Can do.

According to an eighth aspect of the present invention, in the method of manufacturing a liquid jet head according to claim 7, the thinning step is included before the protective film is formed.
In the eighth aspect, since there is a concern that the protective film may be peeled off when the flow path forming substrate wafer is thinned, the protective film is preferably formed after the thinning step.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid ejecting head according to Embodiment 1 of the present invention. FIG. 2 is a plan view of FIG. FIG.

As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a crystal plane orientation of (110) in this embodiment, and one surface thereof is made of silicon oxide (SiO ₂ ) previously formed by thermal oxidation. An elastic film 50 having a thickness of 0.5 to 2.0 μm is formed. In the flow path forming substrate 10, a plurality of pressure generating chambers 12 partitioned by a partition wall 11 are arranged in parallel in the width direction.

  Further, an ink supply path 13 and a communication path 14 that are partitioned by a partition wall 11 and communicate with each pressure generation chamber 12 are provided on one end side in the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10. Furthermore, a communication portion 15 that communicates with each communication path 14 is provided outside the communication path 14. The communication portion 15 communicates with a reservoir portion 32 of the protective substrate 30 described later, and constitutes a part of the reservoir 100 that becomes a common ink chamber (liquid chamber) of each pressure generating chamber 12.

  Here, the ink supply path 13 is formed to have a narrower cross-sectional area than the pressure generation chamber 12, and the flow path resistance of the ink flowing into the pressure generation chamber 12 from the communication portion 15 is kept constant. . For example, in this embodiment, the ink supply path 13 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. In this embodiment, the ink supply path is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path.

  Each communication passage 14 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 toward the communication portion 15 to partition the space between the ink supply path 13 and the communication portion 15. Yes.

  On the opening surface side of the flow path forming substrate 10, a nozzle plate 20 having a nozzle opening 21 communicating with the vicinity of the end portion of each pressure generating chamber 12 on the side opposite to the ink supply path 13 is provided in the pressure generating chamber 12. It is fixed by an adhesive, a heat welding film, or the like through an insulating film 51 used as a mask when forming the film. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, or stainless steel.

  On the other hand, the elastic film 50 having a thickness of, for example, about 1.0 μm is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above. For example, an insulator film 55 of about 0.4 μm is formed. Further, on the insulator film 55, a lower electrode film 60 having a thickness of, for example, about 0.2 μm, a piezoelectric layer 70 having a thickness of, for example, about 1.1 μm, and a thickness of, for example, about 0 A piezoelectric element 300 composed of an upper electrode film 80 of .05 μm is formed. In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode is patterned together with the piezoelectric layer 70 for each pressure generating chamber 12 to form individual electrodes. For example, in this embodiment, the lower electrode film 60 is used as a common electrode for the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode for the piezoelectric element 300. Absent. In addition, the piezoelectric element 300 and a diaphragm that is displaced by driving the piezoelectric element 300 are collectively referred to as an actuator device. In the example described above, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm, but the elastic film 50 and the insulator film 55 are not provided, and only the lower electrode film 60 is left. 60 may be a diaphragm. Further, the piezoelectric element 300 itself may substantially serve as a diaphragm.

  Furthermore, a lead electrode 90 is connected to each upper electrode film 80 that is an individual electrode of the piezoelectric element 300. In the present embodiment, each lead electrode 90 is made of, for example, gold (Au) or the like, and extends from the vicinity of the end of the upper electrode film 80 on the ink supply path 13 side to the insulator film 55. Note that, on the insulator film 55 in the region corresponding to the peripheral edge of the opening of the communication portion 15, there is a metal film 95 made of the same layer as the lead electrode 90 but independent of the lead electrode 90. The metal film 95 remains on the peripheral edge of the opening of the communication portion 15 as a result of manufacturing an ink jet recording head by a manufacturing method described later.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, that is, on the lower electrode film 60, the elastic film 50, and the lead electrode 90, there is a piezoelectric element holding portion 31 for protecting the piezoelectric element 300. The protective substrate 30 is bonded by, for example, an adhesive 35. Note that the space defined by the piezoelectric element holding portion 31 may be sealed or may not be sealed. Further, the protective substrate 30 is provided with a reservoir portion 32 that constitutes at least a part of the reservoir 100 in which the ink supplied to the plurality of pressure generating chambers 12 is stored. In this embodiment, the reservoir portion 32 is formed through the protective substrate 30 in the thickness direction and across the width direction of the pressure generation chamber 12, and is provided in the elastic film 50 and the insulator film 55. The reservoir 100 is configured to communicate with the communication portion 15 through the holes 50a and 55a.

  The material of such a protective substrate 30 is not particularly limited, but it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, a glass material, a ceramic material, and the like. A silicon single crystal substrate which is the same material as the path forming substrate 10 is used.

  Further, the protective substrate 30 is provided with a through-hole 33 that penetrates the protective substrate 30 in the thickness direction, and the vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is in the through-hole 33. Exposed. On the protective substrate 30, a driving circuit 200 for driving the piezoelectric elements 300 arranged in parallel, for example, a circuit board, a semiconductor integrated circuit (IC), and the like are fixed. The drive circuit 200 and the lead electrode 90 are electrically connected by a connection wiring 210 made of a conductive wire such as a bonding wire extending in the through hole 33.

  In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm). The sealing film 41 seals one surface of the reservoir portion 32. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). A region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, and one surface of the reservoir 100 is sealed only with a flexible sealing film 41. ing.

  In such an ink jet recording head of this embodiment, ink is taken in from an ink introduction port connected to an external ink supply means (not shown), and the interior from the reservoir 100 to the nozzle opening 21 is filled with ink. In accordance with the recording signal from, pressure is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the piezoelectric element 300, whereby the pressure in each pressure generation chamber 12 is changed. And the ink droplets are ejected from the nozzle openings 21.

  Hereinafter, a method for manufacturing such an ink jet recording head will be described with reference to FIGS. 3 to 7 are cross-sectional views of the pressure generation chamber 12 in the longitudinal direction.

  First, as shown in FIG. 3A, a flow path forming substrate wafer 110, which is a silicon wafer on which a plurality of flow path forming substrates 10 are integrally formed, is thermally oxidized in a diffusion furnace at about 1100 ° C. A silicon dioxide film 52 to be the elastic film 50 is formed on the entire surface. Further, the elastic film 50 (silicon dioxide film 52) is patterned to form a through hole 50a penetrating the elastic film 50 in a region where the communication portion of the flow path forming substrate wafer 110 is formed. In the present embodiment, a silicon wafer having a relatively large thickness and high rigidity of several hundred μm is used as the flow path forming substrate wafer 110. Further, since the flow path forming substrate wafer 110, which is a silicon wafer, is relatively fragile, for example, an R-shaped chamfered portion 111 is provided at the peripheral portion to prevent occurrence of cracks and the like. Of course, the chamfered portion 111 may be a C surface.

Next, as shown in FIG. 3B, zirconium is formed only on one surface of the elastic film 50 (silicon dioxide film 52), specifically, on the surface where the through hole 50a is formed in the region where the communication portion is formed. A zirconium layer made of (Zr) is formed, and this zirconium layer is thermally oxidized, for example, in a diffusion furnace at 500 to 1200 ° C. to form an insulator film 55 made of zirconium oxide (ZrO ₂ ). Further, the insulator film 55 is patterned to form a through hole 55 a penetrating the insulator film 55 in the insulator film 55 in a region facing the through hole 50 a of the elastic film 50.

  Next, as shown in FIG. 3C, the lower electrode film 60 made of, for example, iridium (Ir), platinum (Pt), or the like is formed over the entire one surface of the flow path forming substrate wafer 110. The lower electrode film 60 is patterned into a predetermined shape.

  Next, as shown in FIG. 3D, a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT), and an upper electrode film 80 made of, for example, iridium are formed on the flow path forming substrate wafer 110. The piezoelectric element 300 is formed by patterning the piezoelectric layer 70 and the upper electrode film 80 in regions facing the respective pressure generation chambers 12 formed on the entire surface of one side.

  Next, as shown in FIG. 4A, a lead electrode 90 is formed. Specifically, first, a metal film 95 made of, for example, gold (Au) or the like is formed over the entire one surface of the flow path forming substrate wafer 110. At this time, the through holes 50 a and 55 a are sealed with the metal film 95. Then, a mask pattern (not shown) made of, for example, a resist or the like is formed on the metal film 95, and the lead electrode 90 is formed by patterning the metal film 95 for each piezoelectric element 300 through the mask pattern. . The metal film 95 in the region corresponding to the through holes 50 a and 55 a is left so as to be discontinuous with the lead electrode 90.

  Next, as shown in FIG. 4B, a protective substrate wafer (bonding substrate) 130 in which a plurality of protective substrates 30 are integrally formed is bonded to the flow path forming substrate wafer 110 with an adhesive 35. Here, as the protective substrate wafer 130, a silicon wafer having a diameter larger than that of the flow path forming substrate wafer 110 is used. Further, similarly to the flow path forming substrate wafer 110, a chamfered portion 131 is also provided at the peripheral portion of the protective substrate wafer 130. Then, the flow path forming substrate wafer 110 and the protective substrate wafer 130 are positioned with high accuracy, and the flow path forming substrate wafer 110 does not protrude from the outside of the protective substrate wafer 130 and does not protrude from the protective substrate wafer 130. Be joined. Thus, the exposed portion 132 where the surface of the protective substrate wafer 130, that is, the bonding surface with the flow path forming substrate wafer 110 is exposed, is disposed on the entire outer periphery of the flow path forming substrate wafer 110. Exists. The protective substrate wafer 130 is a silicon wafer having a thickness of about 400 μm, for example, and the rigidity of the flow path forming substrate wafer 110 is remarkably improved by bonding the protective substrate wafer 130. Further, since the thickness of the flow path forming substrate wafer 110 is reduced in a later step, the flow path forming substrate wafer 110 is not allowed to protrude outside the protective substrate wafer 130, thereby causing the outer periphery contact of the protective substrate wafer 130. Cracking and chipping can be suppressed.

  Next, as shown in FIG. 5A, the flow path forming substrate wafer 110 is processed by processing the surface of the flow path forming substrate wafer 110 opposite to the surface to which the protective substrate wafer 130 is bonded. Set to a predetermined thickness. Specifically, for example, the flow path forming substrate wafer 110 is ground to a certain thickness by a back surface polishing apparatus (back grinder) or the like. Thereafter, wet etching is further performed using an etchant made of hydrofluoric acid or the like to form the flow path forming substrate wafer 110 to a predetermined thickness. For example, in the present embodiment, the flow path forming substrate wafer 110 is rotated while the flow path forming substrate wafer 110 is rotated, and so-called spin etching is performed by spraying an etching solution made of hydrofluoric acid on the surface of the flow path forming substrate wafer 110. The thickness of 110 was set to several tens of μm. It is conceivable that this thinning step is carried out after forming a protective film 150, which will be described later, on the outer periphery of the flow path forming substrate wafer 110. However, the protective film 150 is peeled off during grinding in the thinning step. Therefore, the protective film 150 is preferably performed after the thinning step.

  As a result of reducing the thickness of the flow path forming substrate wafer 110 in this way, the end face (side surface) of the flow path forming substrate wafer 110 is constituted only by the chamfered portion 111. That is, the peripheral portion of the flow path forming substrate wafer 110 having a reduced thickness has a smaller thickness toward the peripheral portion side in the minute range. For this reason, a crack and a chip | tip are easy to generate | occur | produce in the peripheral part of the wafer 110 for flow path formation substrates. In addition, peeling of the insulator film 55 and the like formed on the chamfered portion 111 is likely to occur. Therefore, in the present invention, as described below, the peripheral portion of the flow path forming substrate wafer 110, that is, the chamfered portion 111 is protected.

  That is, as shown in FIG. 5B, the protective film 150 is formed on the surface (exposed portion 132) of the protective substrate wafer 130 so as to cover the end surface (chamfered portion 111) of the flow path forming substrate wafer 110. . Here, the protective film 150 has an etching resistant layer 151 made of a material having etching resistance at least on the surface layer. For example, in the present embodiment, the protective film 150 is composed of only the etching resistant layer 151. Further, the material having etching resistance refers to a material that is not substantially etched with an etching solution when the flow path forming substrate wafer 110 is etched in a process described later. For example, in this embodiment, since the flow path forming substrate wafer 110 is etched using an alkaline solution such as KOH, for example, gold (Au) is suitably used as the material having etching resistance.

  Specifically, first, a resist film 140 is formed on the surface of the flow path forming substrate wafer 110 and a part (the chamfered portion 131) of the exposed portion 132 of the protective substrate wafer 130. Thereafter, a protective film 150 made of gold (Au) is formed on the surface (exposed portion 132) of the protective substrate wafer 130 by plating. For example, in this embodiment, a protective film 150 is formed by electroless plating with a catalyst such as palladium attached to the surface of the protective substrate wafer 130. By forming the protective film 150 by plating in this manner, the protective film 150 can be formed relatively easily to the same thickness as the flow path forming substrate wafer 110, and the flow path forming substrate wafer The protective film 150 is satisfactorily formed up to the lower side of 110 (the chamfered portion 111) (a recess formed at the boundary between the flow path forming substrate wafer 110 and the protective substrate wafer 130). Therefore, the chamfered portion 111 of the flow path forming substrate wafer 110 is reliably covered with the protective film 150.

  In this embodiment, the resist film 140 is provided on the chamfered portion 131 of the protective substrate wafer 130 together with the surface of the flow path forming substrate wafer 110. However, the resist film 140 on the chamfered portion 131 is formed. You don't have to. That is, the protective film 150 may also be formed on the chamfered portion 131 of the protective substrate wafer 130. However, the protective film 150 is preferably formed only in a region facing the protective substrate wafer 130 so as not to protrude to the outside of the protective substrate wafer 130. This is because there is a risk of hindering the transfer of the flow path forming substrate wafer 110 in the subsequent steps.

  Next, as shown in FIG. 6A, the resist film 140 is removed, and an insulating film 51 made of, for example, silicon nitride (SiN) is newly formed on the surface of the flow path forming substrate wafer 110. Patterning into a predetermined shape through a resist or the like that is not performed.

  Next, as shown in FIG. 6B, the flow path forming substrate wafer 110 is wet-etched using an alkaline solution such as an aqueous potassium hydroxide (KOH) solution using the insulating film 51 as a mask. The pressure generating chamber 12, the ink supply path 13, the communication path 14, and the communication portion 15 are formed on the flow path forming substrate wafer 110.

  Here, the laminated film such as the insulator film 55 formed on the chamfered portion 111 is peeled off from the flow path forming substrate wafer 110 when it comes into contact with the etching solution when the flow path forming substrate wafer 110 is etched. There is a risk of becoming a foreign object. Furthermore, since the flow path forming substrate wafer 110 is relatively thin with a thickness of several tens of μm and the chamfered portion 111 is provided, the peripheral edge portion of the flow path forming substrate wafer 110 is very fragile. For this reason, the flow path forming substrate wafer 110 may be cracked or chipped, and the flow path forming substrate wafer 110 itself may be lost and become foreign matter. However, in the present invention, when the flow path forming substrate wafer 110 is etched, the protective film 150 is provided so as to cover the chamfered portion 111 of the flow path forming substrate wafer 110 as described above. No foreign matter is generated due to peeling of 55 or the like or missing of the passage-forming substrate wafer 110. Therefore, it is possible to prevent foreign matters from adhering to the pressure generating chamber 12 and the like and causing defects such as nozzle clogging, and the yield is greatly improved.

  Next, the flow path forming substrate wafer 110 side is immersed in an etching solution, and as shown in FIG. 7A, the metal film 95 in the region facing the through holes 50a and 55a is removed by wet etching, and the penetration is made. The reservoir 100 is formed by communicating the communication portion 15 and the reservoir portion 32 through the holes 50a and 55a. At this time, the protective film 150 provided so as to cover the chamfered portion 111 of the flow path forming substrate wafer 110 is also etched. The protective film 150 does not need to be completely removed, and may be removed so as to be lower than the surface of the flow path forming substrate wafer 110. This is because if it protrudes from the surface of the flow path forming substrate wafer 110, it may become an obstacle when the nozzle plate 20 is joined to the flow path forming substrate wafer 110.

  Note that the metal film 95 between the protective substrate wafer 130 and the flow path forming substrate wafer 110 is not completely etched, so that the metal film 95 remains on the peripheral portions of the through holes 50a and 55a. become.

  After the reservoir 100 is formed in this manner, as shown in FIG. 7B, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by, for example, dicing. Remove by cutting. At this time, the protective film 150 remaining around the flow path forming substrate wafer 110 is also removed at the same time. The nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130 is bonded, and the compliance substrate 40 is bonded to the protective substrate wafer 130. Then, the ink jet recording head having the above-described structure is manufactured by dividing the flow path forming substrate wafer 110 and the like into a single chip size flow path forming substrate 10 as shown in FIG.

  As described above, in the present invention, the flow path forming substrate wafer 110 is etched with the chamfered portion 111 of the flow path forming substrate wafer 110 covered with the protective film 150. As a result, foreign matters generated due to peeling of the insulator film 55 can adhere to the liquid flow path such as the pressure generating chamber 12 to prevent nozzle clogging, and the yield can be greatly improved. .

  As a matter of course, the problem of adhesion of foreign matters is not only in etching the flow path forming substrate wafer 110 but also in any process until the nozzle plate 20 is bonded to the flow path forming substrate wafer 110 thereafter. May also occur. In the present embodiment, since the protective film 150 remains until the step of forming the reservoir 100, that is, immediately before the nozzle plate 20 is joined, problems such as nozzle clogging caused by adhesion of foreign matter can be more reliably prevented. Can do.

  In the present embodiment, the protective film 150 is formed on the surface of the protective substrate wafer 130 by depositing a catalyst such as palladium and plating, but the present invention is not limited to this. Although omitted in the above description, as shown in FIG. 8A, an oxide layer 133 made of silicon dioxide is actually formed on the surface of the protective substrate wafer 130. Therefore, as shown in FIG. 8B, the oxide layer 133 is removed to expose the surface of the protective substrate wafer 130 which is a silicon substrate, and electroless plating is performed in this state to obtain gold (Au). The protective film 150 made of can be satisfactorily formed. Note that the oxide layer 133 is preferably removed only in a region where the protective film 150 is formed. For example, the oxide layer 133 in the region facing the adhesive 35 of the protective substrate wafer 130 is bonded compared to the region where the oxide layer 133 of the protective substrate wafer 130 is removed and the ground of the protective substrate wafer 130 is exposed. This is because the compatibility with the agent is good.

  In the present embodiment, the protective film 150 including only the etching resistant layer 151 is illustrated, but the configuration of the protective film 150 is not limited to this, and the etching resistant layer may be provided on at least the surface layer of the protective film 150. The inside may be formed of other materials. Specifically, for example, as shown in FIG. 9, the protective film 150 includes a filling layer 152 made of, for example, nickel, and an etching resistant layer 151 formed on the surface thereof by, for example, a sputtering method. It may be. The material of the filling layer 152 provided inside the etching resistant layer 151 is not particularly limited, and may be any material that can be favorably formed on the protective substrate wafer 130 such as a metal oxide.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to such embodiment. For example, in the embodiment described above, the pressure generating chamber 12 and the like are formed by etching the flow path forming substrate wafer 110 by wet etching using an alkaline solution, but of course the pressure generating chamber 12 and the like by dry etching. May be formed. In this case, it is necessary to appropriately select the material of the etching resistant layer 151 constituting the protective film 150.

  In the above-described embodiment, the ink jet recording 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 ejects liquid other than ink. Of course, it can also be applied to the head. 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 (field emission 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.

  Furthermore, the present invention is not limited to a method for manufacturing a liquid jet head, and can be widely applied as long as it is a method for manufacturing a silicon device having a silicon substrate.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. 3 is a cross-sectional view illustrating an outline of a method for manufacturing a recording head according to Embodiment 1. FIG. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 4 is a cross-sectional view illustrating the recording head manufacturing method according to the first embodiment. FIG. 6 is a cross-sectional view illustrating a modified example of the recording head manufacturing method according to the first embodiment. FIG. 6 is a cross-sectional view illustrating a modified example of the recording head manufacturing method according to the first embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Ink supply path, 14 Communication path, 15 Communication part, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Piezoelectric element holding part, 32 Reservoir part, 35 Adhesive, 40 Compliance substrate, 50 Elastic film, 55 Insulator film, 60 Lower electrode film, 70 Piezoelectric layer, 80 Upper electrode film, 90 Lead electrode, 100 Reservoir, 110 Channel forming substrate wafer, 111 Chamfered part, 130 Protective substrate Wafer, 131 chamfered portion, 132 exposed portion, 133 oxide layer, 140 resist film, 150 protective film, 151 etching resistant layer, 152 filling layer, 300 piezoelectric element

Claims (8)

A method of manufacturing a silicon device having a silicon substrate processed into a predetermined shape by etching,
A bonding step of bonding a bonding substrate having a diameter larger than that of the silicon wafer to a silicon wafer having a chamfered portion at a peripheral portion; and a thinning step of processing the silicon wafer to which the bonding substrate is bonded to a predetermined thickness; A protective film forming step of forming a protective film having an etching resistant layer made of a material having etching resistance on at least a surface layer so as to cover a chamfered portion of the silicon wafer on the bonding substrate; A method for manufacturing a silicon device, comprising: an etching step for processing into a shape; and a dividing step for dividing the silicon wafer into a plurality of the silicon substrates.   The method for manufacturing a silicon device according to claim 1, wherein a laminated film made of at least one thin film is formed on a surface of the silicon wafer on a side to which the bonding substrate is bonded.   The method for manufacturing a silicon device according to claim 1, wherein the thinning step is included before the protective film forming step.   The method for manufacturing a silicon device according to claim 1, wherein in the etching step, the silicon wafer is formed into a predetermined shape by wet etching using an alkaline solution.   The method for manufacturing a silicon device according to claim 4, wherein the etching resistant layer is made of gold (Au).   6. The method of manufacturing a silicon device according to claim 5, wherein the protective film is composed of only the etching-resistant layer, and the protective film is formed by a plating process. A flow path forming substrate in which a liquid flow path including a pressure generating chamber communicating with a nozzle opening for ejecting liquid is formed, and a pressure provided on one side of the flow path forming substrate to apply pressure to the pressure generating chamber A manufacturing method of a liquid jet head comprising a generating element and a protective substrate bonded to the one surface side of the flow path forming substrate,
A step of forming the pressure generating element on one surface of a wafer for a flow path forming substrate, which is formed of a silicon wafer having a chamfered portion at a peripheral portion and in which a plurality of the flow path forming substrates are integrally formed; A step of bonding a wafer for a substrate and a wafer for a protective substrate in which a plurality of the protective substrates are integrally formed, and a thinning process for processing the wafer for a flow path forming substrate bonded to the bonding substrate to a predetermined thickness And chamfering the flow path forming substrate wafer on the surface of the protective substrate wafer where the protective film having an etching resistant layer made of a material having etching resistance is bonded to the flow path forming substrate wafer. Forming the liquid flow path by etching the flow path forming substrate wafer, and dividing the flow path forming substrate wafer and the protective substrate wafer. The method of manufacturing a liquid jet head, characterized by a step.   The method of manufacturing a liquid jet head according to claim 7, further comprising the thinning step before forming the protective film.

Images