Patent Application
20210291524
The present application is based on, and claims priority from JP Application Serial Number 2020-048805, filed Mar. 19, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a manufacturing method of a liquid ejecting head in which a first flow path substrate and a second flow path substrate are bonded to each other, and a manufacturing method of a flow path component.
A liquid ejecting head disclosed in JP-A-2019-166705 includes a nozzle plate having a plurality of nozzles, a first flow path substrate having a liquid flow path such as a communication passage connected to each nozzle, a second flow path substrate having a liquid flow path such as a pressure chamber connected to each communication passage, and a protective member in order in a stacking direction. Each of these elements is bonded together by an adhesive.
While it is required to make a flow path substrate having a liquid flow path thin, it is difficult to bond the thin liquid flow path to another substrate with high accuracy. In particular, in a case where a part of a circulation flow path for circulating a liquid is formed in the flow path substrate in order to remove air bubbles from each pressure chamber or suppress stagnation of the liquid in the liquid flow path, it is necessary to make the flow path substrate thin to increase a flow path resistance or increase a flow rate of the circulating liquid.
The problems described above are not limited to the liquid ejecting head, but also exist in various flow path components having a liquid flow path.
According to an aspect of the present disclosure, there is provided a manufacturing method of a liquid ejecting head which has a nozzle and a liquid flow path having a pressure chamber to which a pressure for ejecting droplets from the nozzle is applied, and where a first flow path substrate and a second flow path substrate are bonded to each other, the method including: a direct bonding step of directly bonding the first flow path substrate and the second flow path substrate without using an adhesive; and a thinning step of making the second flow path substrate thinner than the first flow path substrate after the direct bonding step.
According to another aspect of the present disclosure, there is provided a manufacturing method of a flow path component which has a liquid flow path and where a first flow path substrate and a second flow path substrate are bonded to each other, the method including: a direct bonding step of directly bonding the first flow path substrate and the second flow path substrate without using an adhesive; and a thinning step of making the second flow path substrate thinner than the first flow path substrate after the direct bonding step.
Hereinafter, embodiments of the present disclosure will be described. Of course, the following embodiments merely exemplify the present disclosure, and not all of the features illustrated in the embodiments are essential for the unit for solving the disclosure.
First, an outline of a technology included in the present disclosure will be described. In addition,
Further, in the present application, a numerical range “Min to Max” means a minimum value Min or more and a maximum value Max or less. A composition ratio represented by a chemical formula indicates a stoichiometric ratio, and a material represented by a chemical formula includes a material that deviates from the stoichiometric ratio.
As illustrated in
In the aspect described above, since the first flow path substrate 210 and the second flow path substrate 220 are directly bonded, the second flow path substrate 220 is bonded to the first flow path substrate 210 with high accuracy. Further, since the second flow path substrate 220 is made thin while being in a supported state by the first flow path substrate 210, the thin second flow path substrate 220 having flow paths 32a to 32e is formed with high accuracy. Therefore, in this aspect, it is possible to manufacture a liquid ejecting head in which a thin layer having a liquid flow path is bonded to another layer with high accuracy.
Further, a flow path component 200 including the first flow path substrate 210 and the second flow path substrate 220 according to one aspect of the present technology has a liquid flow path 60. A manufacturing method according to one aspect of the present technology includes direct bonding steps ST15, ST26, and ST33 of directly bonding the first flow path substrate 210 and the second flow path substrate 220 without using an adhesive, and thinning steps ST16, ST27, and ST34 of making the second flow path substrate 220 thinner than the first flow path substrate 210 after the direct bonding steps ST15, ST26, and ST33.
In the aspect described above, since the first flow path substrate 210 and the second flow path substrate 220 are directly bonded, the second flow path substrate 220 is bonded to the first flow path substrate 210 with high accuracy. Further, since the second flow path substrate 220 is made thin while being in a supported state by the first flow path substrate 210, the thin second flow path substrate 220 having flow paths 32a to 32e is formed with high accuracy. Therefore, in this aspect, it is possible to manufacture a flow path component in which a thin layer having a liquid flow path is bonded to another layer with high accuracy.
As will be described in detail later, the direct bonding between the first flow path substrate 210 and the second flow path substrate 220 includes room temperature bonding, fusion bonding, or the like.
The first flow path substrate 210 may be bonded to the second flow path substrate 220 in a state of having flow paths 31a to 31f existing in the final first flow path substrate 210, or may be bonded to the second flow path substrate 220 in the state of not having the flow paths 31a to 31f.
The second flow path substrate 220 may be bonded to the first flow path substrate 210 in a state of having flow paths 32a to 32e existing in the final second flow path substrate 220, or may be bonded to the first flow path substrate 210 in the state of not having the flow paths 32a to 32e.
The second flow path substrate 220 may be a stacked substrate 240 including a glass substrate 241 and a silicon substrate 242. In this case, the direct bonding step ST26 may be a step of directly bonding the first flow path substrate 210 and the silicon substrate 242. The thinning step ST27 may be a step of separating the glass substrate 241 from the stacked substrate 240.
Further, the second flow path substrate 220 may be an SOI substrate 230 including a silicon oxide layer 233 between a first silicon layer 231 and a second silicon layer 232. Here, SOI is an abbreviation for silicon on insulator. In a case where the second flow path substrate 220 is the SOI substrate 230, the direct bonding step ST15 may be a step of directly bonding the first flow path substrate 210 and the first silicon layer 231. The thinning step ST16 may be a step of separating the second silicon layer 232 from the SOI substrate 230.
Further, the second flow path substrate 220 may be a silicon substrate 250 having a silicon oxide layer 251 on a surface. In this case, the direct bonding step ST33 may be a step of directly bonding the first flow path substrate 210 and the silicon oxide layer 251. The thinning step ST34 may be a step of making the silicon substrate thin by one or more types selected from a group of grinding, etching, and CMP from a surface (for example, an end surface 221) of the silicon substrate on a side opposite to a bonding surface (for example, a second surface 222) with the first flow path substrate 210. Here, CMP is an abbreviation for chemical mechanical polishing.
Here, in the present application, the terms “first”, “second”, “third”, . . . are terms for identifying each configuration element included in a plurality of configuration elements having similarities, and do not mean the order.
The liquid ejecting apparatus 100 illustrated in
A liquid container CT for storing the liquid LQ is mounted on the supply section 14. As the liquid container CT, a hard container made of synthetic resin, a bag-like soft container formed of a flexible film, a liquid tank capable of replenishing the liquid LQ, or the like can be used. In a case where the liquid LQ is ink, the exchangeable hard container is also called an ink cartridge, and the exchangeable soft container is also called an ink pack. The ink is often a neutral or alkaline liquid, but an acidic ink is used. The supply section 14 supplies the liquid LQ to the liquid ejecting head 10.
The liquid ejecting head 10 ejects the liquid LQ from the nozzle NZ into the medium MD as the droplet DR according to the control by the control section 20. An ejecting direction of the droplet DR is the −Z direction on design. In a case where the medium MD is a printing target, the medium MD as a recording medium is a material that holds a plurality of dots DT formed by a plurality of droplets DR. Paper, synthetic resin, cloth, metal, or the like can be used as the medium MD which is the recording medium. A shape of the medium MD which is the recording medium is not particularly limited, such as a rectangle, a roll shape, a substantially circular shape, a polygon other than the rectangle, or a three-dimensional shape. The liquid ejecting apparatus 100 is called an ink jet printer in a case where a printed image is formed on the medium MD which is the recording medium by ejecting ink droplets as the droplets DR.
The liquid LQ widely includes ink, synthetic resin such as photocurable resin, liquid crystal, etching solution, bioorganic substance, lubricating liquid, and the like. The ink widely includes a solution where a dye or the like is dissolved in a solvent, a sol where solid particles such as pigments and metal particles are dispersed in a dispersion medium, and the like.
The transport section 22 transports the medium MD in the +X direction according to the control by the control section 20. In a case where the liquid ejecting apparatus 100 is a line printer in which the medium MD which is the recording medium is transported at a constant speed when a plurality of droplets DR are ejected onto the medium MD which is the recording medium, a plurality of nozzles NZ of the liquid ejecting head 10 are disposed over an entire medium MD in the Y-axis direction. Further, like a serial printer in which the liquid ejecting head 10 scans a plurality of times and performs recording on the medium MD that is the recording medium, the liquid ejecting apparatus 100 may include a reciprocation drive section that moves the liquid ejecting head 10 in the +Y direction and the −Y direction.
For the control section 20, for example, a circuit including a CPU or a FPGA, a ROM, a RAM, and the like can be used. Here, CPU is an abbreviation for central processing unit, FPGA is an abbreviation for field programmable gate array, ROM is an abbreviation for read only memory, and RAM is an abbreviation for random access memory. Further, the control section 20 may be a circuit including a SoC that is an abbreviation for system on a chip. The control section 20 controls an ejecting operation of the droplet DR from the liquid ejecting head 10 by controlling each section included in the liquid ejecting apparatus 100.
In a case where the liquid ejecting apparatus 100 is an ink jet printer, the medium MD is transported by the transport section 22, and when a plurality of droplets DR ejected from the liquid ejecting head 10 land on the medium MD, a plurality of dots DT are formed on the medium MD. Therefore, a printed image is formed on the medium MD which is the recording medium.
The liquid ejecting apparatus may include a circulation path for circulating the liquid in order to remove air bubbles from the pressure chamber communicating with each nozzle and suppress stagnation of the liquid in the liquid flow path. Hereinafter, an example of the circulation path of the liquid ejecting apparatus will be described with reference to
In the plurality of nozzles NZ illustrated in
Each individual flow path 61 has a shape extending in the X-axis direction when viewed in the −Z direction. The pressure chamber C1 included in the individual flow path 61 is a space for storing the liquid LQ ejected from the nozzle NZ communicating with the individual flow path 61. As the pressure of the liquid LQ in the pressure chamber C1 changes, the droplet DR is ejected from the nozzle NZ. One end portion 61a of the individual flow path 61 is connected to the first common liquid chamber R1. The other end portion 61b of the individual flow path 61 is connected to the second common liquid chamber R2. Therefore, the plurality of individual flow paths 61 are located between the first common liquid chamber R1 and the second common liquid chamber R2 in the X-axis direction.
The first common liquid chamber R1 has a shape extending in the Y-axis direction and is disposed over an entire area where the plurality of nozzles NZ exist in the Y-axis direction. The first common liquid chamber R1 is provided with a supply port Ria to which the end portion 61a of each individual flow path 61 is coupled and the liquid LQ is supplied from the supply flow path 121.
The second common liquid chamber R2 has a shape extending in the Y-axis direction, and is disposed over an entire area where the plurality of nozzles NZ exist in the Y-axis direction. The second common liquid chamber R2 is provided with a discharge port R2a to which the end portion 61b of each individual flow path 61 is coupled and where the liquid LQ is returned to the return flow path 122.
From the above, the liquid LQ supplied from the first common liquid chamber R1 to each individual flow path 61 is ejected from the nozzle NZ corresponding to the individual flow path 61. Further, a liquid of the liquid LQ supplied from the first common liquid chamber R1 to each individual flow path 61, which is not ejected from the nozzle NZ, is discharged to the second common liquid chamber R2.
The liquid ejecting apparatus 100 includes a circulation mechanism 110 that circulates the liquid LQ in the circulation flow path 120. The circulation mechanism 110 recirculates the liquid LQ, which is discharged from each individual flow path 61 to the second common liquid chamber R2, to the first common liquid chamber R1. The circulation mechanism 110 illustrated in
The first supply pump 111 supplies the liquid LQ stored in the liquid container CT to the storage container 113. The storage container 113 is a sub-tank that temporarily stores the liquid LQ supplied from the liquid container CT. The storage container 113 is connected to the supply flow path 121 that reaches the supply port R1a of the first common liquid chamber R1 via the second supply pump 112 and a return flow path 122 that reaches the discharge port R2a of the second common liquid chamber R2. The second supply pump 112 sends the liquid LQ stored in the storage container 113 to the supply port R1a along the supply flow path 121. Therefore, the liquid LQ is supplied from the storage container 113 to the first common liquid chamber R1. The liquid LQ stored in the liquid container CT is supplied to the storage container 113 by driving of the first supply pump 111, and the liquid LQ discharged from each individual flow path 61 to the second common liquid chamber R2 is supplied via the return flow path 122.
The liquid ejecting head 10 illustrated in
The nozzle substrate 41 is a plate-like member bonded to the end surface 32g of the second communication substrate 32 in the −Z direction, and has a plurality of nozzles NZ for ejecting liquid LQ. The Z-axis direction is a thickness direction of the nozzle substrate 41. The nozzle substrate 41 illustrated in
A liquid-repellent film having a liquid-repellent property may be provided on the nozzle surface 41a. The liquid-repellent film is not particularly limited as long as it has the liquid-repellent property against a liquid, and for example, a metal film containing a fluorine-based polymer, a molecular film of metal alkoxide having the liquid-repellent property, and the like can be used.
The compliance substrate 42 is bonded to the end surface 32g of the second communication substrate 32 on the outside of the nozzle substrate 41. The compliance substrate 42 illustrated in
The second communication substrate 32 is disposed between the nozzle substrate 41, the compliance substrate 42, and the first communication substrate 31. The Z-axis direction is the thickness direction of the second communication substrate 32. The first communication substrate 31 is bonded to the end surface 32h of the second communication substrate 32 in the +Z direction. The second communication substrate 32 has a flow path 32a common to the plurality of nozzles NZ, flow paths 32b, 32c, and 32d which are a part of individual flow path 61, and a flow path 32e common to the plurality of nozzles NZ. The flow path 32a is a part of the first common liquid chamber R1. The flow path 32e is a part of the second common liquid chamber R2. The flow paths 32a and 32e have a shape having a long opening of which a longitudinal direction is along the Y-axis. Each flow path 32b communicates the flow path 31b of the first communication substrate 31 with the nozzle NZ, and communicates the nozzle NZ with the pressure chamber C1. Each flow path 32c communicates the pressure chamber C1 with the flow path 41b of the nozzle substrate 41. Each flow path 32d communicates the flow path 41b of the nozzle substrate 41 with the flow path 31d of the first communication substrate 31.
The second communication substrate 32 can be formed of, for example, one or more materials selected from a silicon substrate, metal, ceramic, and the like. The second communication substrate 32 is formed by processing a silicon single crystal substrate by using, for example, a semiconductor manufacturing technology such as photolithography and etching.
The first communication substrate 31 is disposed between the second communication substrate 32, the pressure chamber substrate 33, and the housing member 36. The Z-axis direction is the thickness direction of the first communication substrate 31. The pressure chamber substrate 33 and the housing member 36 are bonded to the end surface 31h of the first communication substrate 31 in the +Z direction. The first communication substrate 31 has the flow path 31a common to the plurality of nozzles NZ, the flow paths 31b, 31c, 31d, and 31e which are a part of the individual flow path 61, and the flow path 31f common to the plurality of nozzles NZ. The flow path 31a is a part of the first common liquid chamber R1. The flow path 31f is a part of the second common liquid chamber R2. The flow paths 31a and 31f have a shape having a long opening of which the longitudinal direction is along the Y-axis. Each flow path 31b communicates the first common liquid chamber R1 with the pressure chamber C1. Each flow path 31c communicates the pressure chamber C1 with the flow path 32b of the second communication substrate 32. Each flow path 31d communicates the flow path 32b with the flow path 32c in the second communication substrate 32. Each flow path 31e communicates the flow path 32d of the second communication substrate 32 with the second common liquid chamber R2.
The first communication substrate 31 can be formed of, for example, one or more materials selected from a silicon substrate, metal, ceramic, and the like. The first communication substrate 31 is formed by processing a silicon single crystal substrate by using, for example, a semiconductor manufacturing technology such as photolithography and etching.
The pressure chamber substrate 33 has a plurality of pressure chambers C1 where the pressure for ejecting the liquid LQ from the nozzle NZ is applied to the liquid LQ. The pressure chamber substrate 33 includes a vibration plate 33b and a drive element 34 on a surface on a side opposite to the first communication substrate 31. Here, a portion of the pressure chamber substrate 33 in the −Z direction with respect to the vibration plate 33b is referred to as a pressure chamber substrate main body section 33a.
The pressure chamber substrate main body section 33a is bonded to the end surface 31h of the first communication substrate 31 in the +Z direction. The pressure chamber substrate main body section 33a has the pressure chamber C1 separated for each nozzle NZ. Each pressure chamber C1 is located between the second communication substrate 32 and the vibration plate 33b, and is a long space of which a longitudinal direction is along the X-axis. The pressure chamber substrate main body section 33a has a pressure chamber row in which a plurality of pressure chambers C1 are aligned in the Y-axis direction in two rows in the X-axis direction. Each pressure chamber C1 is connected to the flow path 31b of the first communication substrate 31 on one end side in the longitudinal direction, and is connected to the flow path 31c of the first communication substrate 31 on the other end side in the longitudinal direction.
The pressure chamber substrate main body section 33a can be formed of, for example, one or more materials selected from a silicon substrate, metal, ceramic, and the like. The pressure chamber substrate main body section 33a is formed by processing a silicon single crystal substrate by using, for example, a semiconductor manufacturing technology such as photolithography and etching. In this case, if a silicon oxide layer is formed on a surface of the silicon single crystal substrate by thermal oxidation or the like, the silicon oxide layer can be used for the vibration plate 33b. Of course, a known material and manufacturing method can be optionally adopted for forming the pressure chamber substrate main body section 33a.
The vibration plate 33b integrated with the pressure chamber substrate main body section 33a has elasticity and forms a part of the wall surface of the pressure chamber C1. The vibration plate 33b can be formed of, for example, one or more materials selected from silicon oxide abbreviated as SiOx, metal oxide, ceramic, synthetic resin, and the like. SiOx is silicon dioxide SiO2 in stoichiometric ratio, but it may actually deviate from x=2. The vibration plate 33b can be formed by, for example, a physical vapor deposition method including thermal oxidation and sputtering, a vapor deposition method including CVD, a liquid phase method including spin coating, and the like. Here, CVD is an abbreviation for chemical vapor deposition.
The vibration plate 33b may include a plurality of layers such as an elastic layer and an insulating layer. For example, the vibration plate 33b is formed by stacking SiOx as an elastic layer on the pressure chamber substrate main body section 33a and stacking zirconium oxide abbreviated as ZrOx as an insulating layer on the elastic layer.
Of course, in addition to the above description, the material of the vibration plate 33b may be silicon nitride abbreviated as SiNx, titanium oxide abbreviated as TiOx, aluminum oxide abbreviated as AlOx, hafnium oxide abbreviated as HfOx, magnesium oxide abbreviated as MgOx, lanthanum aluminate, or the like.
The drive element 34 of which drive is divided for each pressure chamber C1 is integrated with a drive element disposition surface 33c which is an end surface of the vibration plate 33b in the +Z direction. The drive element 34 and the vibration plate 33b are included in an actuator that applies a pressure to the pressure chamber C1. Each drive element 34 is a long structure of which a longitudinal direction is along the X-axis. It is assumed that each drive element 34 of this specific example is a piezoelectric element that expands or contracts according to a drive signal including repetition of a drive pulse having a voltage change. The piezoelectric element includes, for example, a layered first electrode, a piezoelectric layer, and a layered second electrode in order in the +Z direction, and expands or contracts according to a voltage applied between the first electrode and the second electrode. In the plurality of drive elements 34, at least one layer of the first electrode, the piezoelectric layer, and the second electrode may be individually divided between the drive elements 34. Therefore, in the plurality of drive elements 34, the common electrode to which the first electrode is connected may be used, the common electrode to which the second electrode is connected may be used, or the piezoelectric layer may be connected. The first electrode and the second electrode can be formed of, for example, a conductive material such as a metal such as iridium or platinum, or a conductive metal oxide such as indium tin oxide abbreviated as ITO. The piezoelectric layer can be formed of, for example, a material having a perovskite structure such as lead zirconate titanate abbreviated as PZT, a relaxer ferroelectric in which any metal such as niobium or nickel is added to PZT, and a lead-free perovskite oxide such as BiFeOx-BaTioy piezoelectric material.
The drive element 34 is not limited to the piezoelectric element, and may be a heat generating element or the like that generates air bubbles in the pressure chamber due to heat generation.
The protective substrate 35 has a space 35a for protecting a plurality of drive elements 34 and a through-hole 35b for pulling out the wiring substrate 51, and is bonded to the drive element disposition surface 33c which is an end surface of the vibration plate 33b in the +Z direction. Therefore, the protective substrate 35 reinforces a mechanical strength of the pressure chamber substrate 33. The protective substrate 35 can be formed of, for example, one or more materials selected from a silicon substrate, metal, ceramic, synthetic resin, and the like. The protective substrate 35 is formed by processing a silicon single crystal substrate by using, for example, a semiconductor manufacturing technology such as photolithography and etching. Of course, a known material and manufacturing method can be optionally adopted for forming the protective substrate 35.
The housing member 36 is bonded to the end surface 31g of the first communication substrate 31 in the +Z direction on the outside of the pressure chamber substrate 33 and the protective substrate 35. The housing member 36 illustrated in
The wiring substrate 51 is a flexible mounting component including the drive circuit 52 of the drive element 34, and is coupled to the end surface of the vibration plate 33b in the +Z direction between the drive element rows. A coupling portion of the wiring substrate 51 with respect to the vibration plate 33b is, for example, coupled to the first electrode and the second electrode via lead wiring. For the wiring substrate 51, FPC, FFC, COF, or the like can be used. Here, FPC is an abbreviation for a flexible printed circuit. FFC is an abbreviation for a flexible flat cable. COF is an abbreviation for a chip on film. A drive signal and a reference voltage for driving the drive element 34 are supplied from the wiring substrate 51 to each drive element 34. As a constituent metal of the lead wiring, one or more of Au, Pt, Al, Cu, Ni, Cr, Ti, and the like can be used. The lead wiring may include an adhesion layer such as nichrome abbreviated as NiCr.
As illustrated in
As described above, the liquid flow path 60 including a part of the circulation flow path 120 for circulating the liquid LQ passing through the pressure chamber C1 has a complicated structure.
By the way, the second communication substrate 32 to which the nozzle substrate 41 is bonded has a flow path which has a very thin thickness, for example, about 20 to 100 μm, which is a length in the +Z direction, and is longer than its own thickness in a direction orthogonal to the +Z direction. For example, a length L1 of the longest flow path in the individual flow path 61 is about 100 to 200 μm in a range longer than the thickness of the second communication substrate 32. The length L1 is a length in the X-axis direction orthogonal to the +Z direction which is the thickness direction of the second communication substrate 32. The length L2 of the first common liquid chamber R1 in the X-axis direction is about 400 to 600 μm, and the length L3 of the second common liquid chamber R2 in the X-axis direction is also about 400 to 600 μm. Further, the length of the first common liquid chamber R1 in the Y-axis direction is about 20 to 30 mm, and the length of the second common liquid chamber R2 in the Y-axis direction is also about 20 to 30 mm. That is, the second communication substrate 32 has a flow path longer than the thickness of the second flow path substrate 220 as a part of the circulation flow path 120. Therefore, it is difficult to bond the thin second communication substrate having a long flow path to the first communication substrate with high accuracy. In particular, in a case where the second communication substrate has a part of the circulation flow path, it is necessary to make the second communication substrate thin in order to increase a flow path resistance and a flow rate of the circulating liquid.
Therefore, in this specific example, after the first communication substrate and the second communication substrate are directly bonded to each other without using the adhesive, the second communication substrate is made thinner than the first communication substrate. The first communication substrate 31 is an example of a first flow path substrate, and the second communication substrate 32 is an example of a second flow path substrate. Hereinafter, an example of a manufacturing method of the liquid ejecting head 10 including the flow path component 200 where the first flow path substrate 210 and the second flow path substrate 220 are bonded will be described with reference to
First, as the SOI substrate 230 used in a SOI thinning step ST11 illustrated in
The first flow path substrate 210 bonded to the second flow path substrate 220 is preferably formed from a silicon single crystal substrate. In the first flow path substrate 210 illustrated in
After the SOI substrate preparation step, an SOI thinning step ST11 is performed in which the first silicon layer 231 of the SOI substrate 230 is made thin according to the thickness of the second flow path substrate 220, for example, about 20 to 100 μm. In the first silicon layer 231, the second surface 222, which is the end surface in the +Z direction, is scraped. The first silicon layer 231 can be made thin by one or more types selected from CMP, grinding, and etching. Here, CMP is an abbreviation for chemical mechanical polishing. The etching may be wet etching or dry etching.
A surface roughness Ra of the second surface 222 to which the first flow path substrate 210 is bonded in the subsequent direct bonding step ST15 is preferably 1 nm or less. Therefore, it is preferable to form a so-called mirror surface on the second surface 222 by performing a CMP treatment with a CMP apparatus. Further, in a case of combining grinding and CMP or combining etching and CMP, it is preferable to form a mirror surface by finally performing the CMP treatment on the second surface 222.
Next, a mask forming step ST12 is performed in which a pattern of the resist mask RS1 is formed by using photolithography on a portion of the second surface 222 of the first silicon layer 231, where the flow paths 32a to 32e are not formed.
Next, a second liquid flow path forming step ST13 is performed in which the liquid flow path 228 is formed as the flow paths 32a to 32e in the first silicon layer 231 by etching the first silicon layer 231 using the silicon oxide layer 233 as an etching stop layer. A second liquid flow path forming step ST13 is an example of a liquid flow path forming step of forming a flow path longer than the thickness of the second flow path substrate on the second flow path substrate. The etching of the first silicon layer 231 may be wet etching or dry etching. For the wet etching, for example, anisotropic etching can be used by using an alkaline solution such as potassium hydroxide aqueous solution, TMAH aqueous solution, or EDP aqueous solution as an etchant. For the dry etching, for example, plasma dry etching can be used. In the second liquid flow path forming step ST13, a flow path longer than the thickness of the second flow path substrate 220 in a direction orthogonal to the Z-axis direction is formed on the second flow path substrate 220 as a part of the circulation flow path 120. By performing the second liquid flow path forming step ST13 of forming the flow path longer than the thickness of the second flow path substrate 220 in a direction intersecting the Z-axis direction as the flow paths 32a to 32e on the second flow path substrate 220, a flow path design of a narrow flow path portion near the nozzle NZ becomes easy. Further, since the flow path longer than the thickness of the second flow path substrate 220 is a part of the circulation flow path 120, in addition to facilitating the flow path design of the narrow flow path portion near the nozzle NZ, a design of the circulation flow path 120 or the like becomes easy.
Next, a mask removing step ST14 is performed in which the resist mask RS1 is removed from the second surface 222. The resist mask RS1 can be removed by a chemical solution, oxygen plasma, or the like.
Next, as illustrated in
It is preferable that the first surface 211, which is the end surface of the first flow path substrate 210 having the liquid flow path 218 in the −Z direction, is subjected to CMP in order to obtain a mirror surface. Further, in a case where the first surface 211 is scraped by combining grinding and CMP, or combining etching and CMP, it is preferable to use CMP finally. The direct bonding includes room temperature bonding, fusion bonding, or the like.
The room temperature bonding is performed, for example, as follows.
When the first surface 211 of the first flow path substrate 210 and the second surface 222 of the second flow path substrate 220 are irradiated with either an ion beam or a neutron beam under a high vacuum of 10−5 to 10−1 Pa, silicon bonding hands appear on the first surface 211 and the second surface 222, and the first surface 211 and the second surface 222 are in an activated state. For the ion beam, for example, ions of an inert gas such as argon are used. In a state where the first surface 211 and the second surface 222 are activated, when the activated first surface 211 and the activated second surface 222 are in contact with each other, the bonding hands are tied together, and the first surface 211 and the second surface 222 are bonded. Therefore, in theory, a strength comparable to that of the silicon substrate itself can be obtained. The direct bonding treatment is performed at room temperature.
That is, in the manufacturing method of this specific example, in the direct bonding step ST15, the first surface 211 of the first flow path substrate 210 and the second surface 222 of the second flow path substrate 220 are irradiated with the ion beam and the neutron beam under vacuum so that the first surface 211 and the second surface 222 are activated, and the activated first surface 211 and the activated second surface 222 are in contact with each other to bond the first surface 211 and the second surface 222. Since the room temperature bonding does not require heating or a high temperature, the bonding position is unlikely to shift. Further, since gas is rarely generated at the bonding surface between the flow path substrates, voids are unlikely to occur at the bonding surface. Therefore, the room temperature bonding is a preferable direct bonding.
The fusion bonding is a method in which the first surface 211 and the second surface 222 are in close contact with each other by a hydrogen bond between hydroxyl groups in a state where the hydroxyl groups are formed on the first surface 211 and the second surface 222, and the direct bonding is realized with oxygen by a high temperature treatment. For example, when a silicon oxide layer is formed on the first surface 211 and the second surface 222, hydroxyl groups are formed on the first surface 211 and the second surface 222 due to the moisture in the air. In this state, when the first surface 211 and the second surface 222 are in close contact with each other and then heated to a high temperature of 800° C. or higher, preferably about 1200° C., an oxygen-mediated direct bond of Si—O—Si is formed.
Plasma activation bonding can also be provided, which lowers the bonding temperature by a hydrophilization treatment of the first surface 211 and the second surface 222, that is, the first surface 211 and the second surface 222 are irradiated with plasma of oxygen or nitrogen in advance in order to lower a heating temperature. The plasma activation bonding is a type of the fusion bonding, and the heating temperature can be about 200 to 300° C.
That is, in the manufacturing method of this specific example, in the direct bonding step ST15, the hydroxyl groups are formed on the first surface 211 of the first flow path substrate 210 and the second surface 222 of the second flow path substrate 220. The first surface 211 and the second surface 222 are bonded by heating in a state where the first surface 211 having the hydroxyl group and the second surface 222 having the hydroxyl group are in contact with each other. The fusion bonding is a preferable direct bonding because the first surface 211 and the second surface 222 have a high bonding force, so that the first surface 211 and the second surface 222 can be easily bonded, and a high vacuum is not required. In particular, the plasma activation bonding is a more preferable direct bonding because it does not require a high temperature of 800° C. or higher.
After the second liquid flow path forming step ST13, the direct bonding step ST15 is performed in which the first flow path substrate 210 and the first silicon layer 231 are directly bonded to each other without using the adhesive so that bending of the second flow path substrate 220 is suppressed. Therefore, in this specific example, the liquid flow path 228 can be precisely processed while preventing the second flow path substrate 220 from warpage or the like, and the liquid flow path 228 can be formed with high accuracy.
After the direct bonding step ST15, the thinning step ST16 is performed in which the second flow path substrate 220 is made thinner than the first flow path substrate 210 with respect to the flow path component 200 where the first flow path substrate 210 and the second flow path substrate 220 are directly bonded. The thinning step ST16 can be performed, for example, by dissolving the silicon oxide layer 233 with an etchant and separating the second silicon layer 232 from the SOI substrate 230. The second silicon layer 232 is separated from the SOI substrate 230 by, for example, one of wet etching using fluorinated acid that is, hydrofluoric acid as an etchant, etching with hydrofluoric acid vapor, a combination of grinding and the above-mentioned wet etching, and the like.
In this specific example in which the thinning step ST16 described above is performed, the second silicon layer 232 having no liquid flow path can be removed from the flow path component 200 without deteriorating the liquid flow path 60 of the flow path component 200.
As described above, in the manufacturing method of this specific example, in the thinning step ST16, the second flow path substrate 220 is divided in the middle of the second flow path substrate 220 in the thickness direction so that a portion which is not bonded to the first flow path substrate 210 is separated from the second flow path substrate 220. Therefore, in this specific example, the second flow path substrate 220 can be easily made thin.
After the thinning step ST16, a first protective film forming step ST17 is performed in which a first protective film 301 is formed on the surfaces of the first flow path substrate 210 and the second flow path substrate 220. As illustrated in
In particular, the protective film 300 preferably includes any oxide selected from a group of tantalum oxide abbreviated as TaOx, hafnium oxide abbreviated as HfOx, and zirconium oxide abbreviated as ZrOx. TaOx is ditantalum pentoxide Ta2O5 in stoichiometric ratio, but it may actually deviate from x=2.5. TaOx has a characteristic that it is difficult to dissolve in an alkali and insoluble in an acidic solution other than hydrofluoric acid if the film density is, for example, as high as about 7 g/cm2. Therefore, the protective film including TaOx is effective as a protective film against a strong alkaline solution or a strong acid solution. HfOx is hafnium dioxide HfO2 in stoichiometric ratio, but it may actually deviate from x=2. HfOx has a characteristic of being insoluble in both alkali and acid. Therefore, the protective film including HfOx is versatile as a protective film against a strong alkaline solution or a strong acid solution. ZrOx is zirconium dioxide ZrO2 in stoichiometric ratio, but it may actually deviate from x=2. ZrOx has a characteristic of being insoluble in alkali and insoluble in acidic solutions other than sulfuric acid and hydrofluoric acid. Therefore, the protective film including ZrOx is effective as a protective film against a strong alkaline solution or a strong acid solution.
The protective film 300 can be formed by one or more film forming methods selected from atomic layer deposition abbreviated as ALD, CVD, sputtering, and the like. In particular, if the protective film 300 is formed by ALD, the protective film 300 is formed on an inner surface of the liquid flow path having a complicated shape with a substantially uniform film thickness and good coverage, and is in a dense state with a high film density. In particular, the protective film 300 having the high film density is surely formed even in a region where coverage failure is likely to occur, such as a corner of the complicated liquid flow path 60 included in the circulation flow path 120, or the like. The formation of the protective film 300 by ALD is preferably performed at a temperature of 200° C. or lower, preferably 100° C. or lower, in order to suppress deterioration of the liquid ejecting head 10. Further, in order to suppress a reaction by-product, it is preferable that the protective film 300 is formed by ALD at a temperature of 50° C. or higher.
Since ALD is a method for facilitating film formation even in a hidden narrow portion, unlike film formation having high straightness such as sputtering, it is preferable to form the protective film 300 by ALD.
After the first protective film forming step ST17, a nozzle substrate bonding step ST18 is performed in which the thinned second flow path substrate 220 and the nozzle substrate 41 having the nozzle NZ are bonded. The nozzle substrate 41 can be formed from, for example, a wafer for a nozzle substrate, which is a silicon wafer. The method for forming the nozzle NZ on the wafer for the nozzle substrate is not particularly limited, and for example, the nozzle NZ is formed by etching the wafer for the nozzle substrate via a mask. For the bonding between the second flow path substrate 220 and the nozzle substrate 41, bonding with the adhesive, the above-mentioned direct bonding, or the like can be used.
In this specific example, since the thin second flow path substrate 220 has the liquid flow path 228 near the nozzle NZ, the flow path design of the narrow flow path portion near the nozzle NZ becomes easy.
The flow path component 200 having the first protective film 301 is divided into chips from a wafer state by any of dividing unit such as laser irradiation or blade dicing.
The pressure chamber substrate 33 illustrated in
The protective substrate 35 illustrated in
As described above, the liquid ejecting head 10 including the flow path component 200 illustrated in
In this specific example, since the flow path substrates having through-holes and grooves formed as the liquid flow path 60 are bonded to each other, a complicated flow path such as a horizontal hole can also be formed. In this specific example, since the flow path substrate on one side can be made thin after bonding the flow path substrates to each other, the risk of chips or cracks that may occur when the thin flow path substrate is processed in a unit is suppressed. Since the SOI substrate is composed of Si and SiOx, this specific example has a degree of freedom in the process treatment method when forming a through-hole pattern or peeling off a resist mask.
As described above, the first flow path substrate 210 and the second flow path substrate 220 are directly bonded to each other without using the adhesive, and after the direct bonding, the second flow path substrate 220 is made thinner than the first flow path substrate 210. Since the first flow path substrate 210 and the second flow path substrate 220 are directly bonded, the second flow path substrate 220 is bonded to the first flow path substrate 210 with high accuracy. Further, since the second flow path substrate 220 is made thin in a state of being supported by the first flow path substrate 210, warpage of the second flow path substrate 220 or the like is prevented, and the thin second flow path substrate 220 having the flow paths 32a to 32e is formed with high accuracy. Therefore, in this specific example, it is possible to manufacture the liquid ejecting head 10 including the flow path component 200 where a thin layer having the liquid flow path is bonded to another layer with high accuracy.
The glass substrate 241 illustrated in
As the silicon substrate 242, a silicon polycrystalline substrate having a surface index of (110) or (111) can be used. The first flow path substrate 210 bonded to the silicon substrate 242 is preferably formed from a silicon single crystal substrate. In the first flow path substrate 210 illustrated in
First, an adhesive layer forming step is performed in which the adhesive layer 244 is formed on one surface of the silicon substrate 242 which is a part of the stacked substrate 240 illustrated in
After that, a sticking step ST21 is performed in which the adhesive layer 244 and the glass substrate 241 are stuck. For example, the adhesive layer 244 and the glass substrate 241 can be stuck together by heat bonding. The stacked substrate 240 on which the sticking step ST21 is performed includes the adhesive layer 244 between the glass substrate 241 and the silicon substrate 242.
After the sticking step ST21, a stacked substrate thinning step ST22 is performed in which the silicon substrate 242 of the stacked substrate 240 is made thin according to the thickness of the second flow path substrate 220, for example, about 20 to 100 μm. The second surface 222, which is the end surface of the silicon substrate 242 in the +Z direction, is scraped. The silicon substrate 242 can be made thin by one or more types selected from CMP, grinding, and etching. The etching may be wet etching or dry etching. The surface roughness Ra of the second surface 222 to which the first flow path substrate 210 is bonded in the subsequent direct bonding step ST26 is preferably 1 nm or less. Therefore, it is preferable to form a mirror surface on the second surface 222 by performing a CMP treatment with a CMP apparatus. Further, in a case of combining grinding and CMP or combining etching and CMP, it is preferable to form a mirror surface by finally performing the CMP treatment on the second surface 222.
Next, a mask forming step ST23 is performed in which the pattern of the resist mask RS1 is formed on a portion of the second surface 222 of the silicon substrate 242, where the flow paths 32a to 32e are not formed, by using photolithography.
Next, a second liquid flow path forming step ST24 is performed in which the liquid flow path 228 is formed as the flow paths 32a to 32e on the silicon substrate 242 by etching the silicon substrate 242. The second liquid flow path forming step ST24 is an example of a liquid flow path forming step of forming a flow path longer than the thickness of the second flow path substrate on the second flow path substrate. The etching of the silicon substrate 242 may be wet etching or dry etching. For the wet etching, for example, anisotropic etching can be used by using an alkaline solution such as potassium hydroxide aqueous solution, TMAH aqueous solution, or EDP aqueous solution as an etchant. For the dry etching, for example, plasma dry etching can be used. In the second liquid flow path forming step ST24, the flow path longer than the thickness of the second flow path substrate 220 in a direction orthogonal to the Z-axis direction is formed on the second flow path substrate 220 as a part of the circulation flow path 120. By performing the second liquid flow path forming step ST24 of forming the flow path longer than the thickness of the second flow path substrate 220 in a direction intersecting the Z-axis direction as the flow paths 32a to 32e on the second flow path substrate 220, the flow path design of the narrow flow path portion near the nozzle NZ becomes easy. Further, since the flow path longer than the thickness of the second flow path substrate 220 is a part of the circulation flow path 120, in addition to facilitating the flow path design of the narrow flow path portion near the nozzle NZ, a design of the circulation flow path 120 or the like becomes easy.
Next, as illustrated in
Next, a direct bonding step ST26 is performed in which the first surface 211 of the first flow path substrate 210 and the second surface 222 of the second flow path substrate 220 are directly bonded to each other without using the adhesive. As described above, by directly bonding the first flow path substrate 210 and the second flow path substrate 220 without using the adhesive, durability of a flow path component in which the substrates are bonded is improved, and good droplet ejection characteristics are maintained for a long period of time, and it is possible to form a complicated flow path structure that has a liquid circulation path.
It is preferable that the first surface 211, which is the end surface of the first flow path substrate 210 having the liquid flow path 218 in the −Z direction, is subjected to CMP in order to obtain a mirror surface. Further, in a case where the first surface 211 is scraped by combining grinding and CMP, or combining etching and CMP, it is preferable to use CMP finally. As described above, the direct bonding includes room temperature bonding, fusion bonding, and the like.
After the second liquid flow path forming step ST24, a direct bonding step ST26 is performed in which the first flow path substrate 210 and the silicon substrate 242 are directly bonded to each other without using the adhesive, so that bending of the second flow path substrate 220 is suppressed. Therefore, in this specific example, the liquid flow path 228 can be precisely processed while preventing the second flow path substrate 220 from warpage or the like, and the liquid flow path 228 can be formed with high accuracy.
After the direct bonding step ST26, a thinning step ST27 is performed in which the second flow path substrate 220 is made thinner than the first flow path substrate 210 with respect to the flow path component 200 where the first flow path substrate 210 and the second flow path substrate 220 are directly bonded. The thinning step ST27 can be performed, for example, by irradiating the stacked substrate 240 with light that weakens adhesion of the adhesive layer 244 from a glass substrate 241 side and separating the glass substrate 241 from the stacked substrate 240. If laser light is used as the light that weakens adhesion of the adhesive layer 244, the adhesive force of the adhesive layer 244 is reduced, so that the glass substrate 241 can be easily separated from the stacked substrate 240. A wavelength of the laser light can be between about 355 nm of ultraviolet rays and about 1064 nm of infrared rays. The adhesive remaining on the end surface 221 of the second flow path substrate 220 in the −Z direction is dissolved and removed by chemical cleaning. Further, in a case where the double-sided tape that is peeled off by gas generation due to ultraviolet irradiation is used for the adhesive layer 244, when the ultraviolet rays are used as the light for weakening the bonding of the adhesive layer 244, gas is generated from the adhesive layer of the double-sided tape due to the ultraviolet rays and the adhesive force of the adhesive layer is reduced. Therefore, the glass substrate 241 can be easily separated from the stacked substrate 240. Since the double-sided tape adhering to the silicon substrate 242 is bonded to the silicon substrate 242 in a release film, the double-sided tape can be easily peeled off from the silicon substrate 242.
In this specific example in which the thinning step ST16 described above is performed, the glass substrate 241 can be removed from the flow path component 200 without deteriorating the liquid flow path 60 of the flow path component 200.
As described above, in the manufacturing method of this specific example, in the thinning step ST27, a portion not bonded to the first flow path substrate 210 is separated from the second flow path substrate 220 by dividing the second flow path substrate 220 in the middle of the second flow path substrate 220 in the thickness direction. Therefore, in this specific example, the second flow path substrate 220 can be easily made thin.
After the thinning step ST27, a first protective film forming step ST28 is performed in which the first protective film 301 is formed on the surfaces of the first flow path substrate 210 and the second flow path substrate 220. As the first protective film 301, a material capable of being used for the protective film 300 described above can be used. The first protective film 301 can be formed by one or more film forming methods selected from ALD, CVD, sputtering, and the like, and it is preferable to be formed by ALD which can easily form a film even in a narrow portion of the liquid flow path.
After the first protective film forming step ST28, a nozzle substrate bonding step ST18 is performed in which the thinned second flow path substrate 220 and the nozzle substrate 41 having the nozzle NZ are bonded. The nozzle substrate bonding step ST18 is illustrated in
Of course, for bonding the first flow path substrate 210 and the pressure chamber substrate 33, bonding with the adhesive, the above-mentioned direct bonding, or the like can be used. Further, if the protective substrate 35 illustrated in
In this specific example, since the flow path substrates having through-holes and grooves formed as the liquid flow path 60 are bonded to each other, a complicated flow path such as a horizontal hole can also be formed. In this specific example, since the flow path substrate on one side can be made thin after bonding the flow path substrates to each other, the risk of chips or cracks that may occur when the thin flow path substrate is processed in a unit is suppressed.
As described above, the first flow path substrate 210 and the second flow path substrate 220 are directly bonded to each other without using the adhesive, and after the direct bonding, the second flow path substrate 220 is made thinner than the first flow path substrate 210. Since the first flow path substrate 210 and the second flow path substrate 220 are directly bonded, the second flow path substrate 220 is bonded to the first flow path substrate 210 with high accuracy. Further, since the second flow path substrate 220 is made thin in a state of being supported by the first flow path substrate 210, warpage of the second flow path substrate 220 or the like is prevented, and the thin second flow path substrate 220 having the flow paths 32a to 32e is formed with high accuracy. Therefore, in this specific example, it is possible to manufacture the liquid ejecting head 10 including the flow path component 200 where a thin layer having the liquid flow path is bonded to another layer with high accuracy. 6. Third Specific Example of Manufacturing Method of Liquid Ejecting Head:
First, a first liquid flow path forming step ST31 is performed in which the liquid flow path 218 is formed as the flow paths 31a to 31f on the silicon substrate to be the first flow path substrate 210. The first flow path substrate 210 is obtained, for example, by forming the liquid flow path 218 by etching the silicon single crystal substrate having a surface index of (110) via a mask.
Next, a silicon oxide layer forming step ST32 is performed in which the silicon oxide layers 215 and 251 are formed on the surface of the first flow path substrate 210 having the liquid flow path 218 and the surface of the silicon substrate to be the second flow path substrate 220. The thickness of the silicon oxide layers 215 and 251 of the first flow path substrate 210 and the silicon substrate 250 is preferably 0.5 μm or more and more preferably 1 μm or more. In particular, the thickness of the silicon oxide layer 251 of the silicon substrate 250 is preferably 1 μm or more from the viewpoint of forming the liquid flow path 228 on the silicon substrate 250. Further, the thickness of the silicon oxide layers 215 and 251 is preferably 10 μm or less and more preferably 5 μm or less, from the viewpoint of suppressing the occurrence of warpage, cracks, or the like in the flow path component 200 due to the film stress of the silicon oxide layers 215 and 251. The formation of the silicon oxide layers 215 and 251 on the silicon substrate is preferably performed by thermal oxidation at a temperature of about 800 to 1200° C., and wet oxidation is preferable to dry oxidation.
The first surface 211 having the silicon oxide layer 215 in the first flow path substrate 210 and the second surface 222 having the silicon oxide layer 251 in the silicon substrate 250 may be subjected to CMP in order to obtain a mirror surface.
Next, a direct bonding step ST33 is performed in which the first surface 211 of the first flow path substrate 210 and the second surface 222 of the silicon substrate 250 are directly bonded to each other without using the adhesive. In the direct bonding step ST33 illustrated in
By performing the direct bonding step ST33 of directly bonding the first flow path substrate 210 and the silicon oxide layer 251 without using the adhesive, the bending of the second flow path substrate 220 is suppressed and the second flow path substrate 220 can be used as a stop layer in a subsequent second liquid flow path forming step ST36. Therefore, in this specific example, the liquid flow path 228 can be formed with high accuracy and an efficient manufacturing step can be provided.
After the direct bonding step ST33, a thinning step ST34 is performed in which the silicon substrate 250 is made thinner than the first flow path substrate 210 with respect to the flow path component 200 where the first flow path substrate 210 and the silicon substrate 250 are directly bonded. In the thinning step ST34, a treatment of thinning silicon substrate 250 is performed by one or more types selected from a group of grinding, etching, and CMP from the end surface 221 in the silicon substrate 250 on a side opposite to the second surface 222 which is the bonding surface with the first flow path substrate 210. The etching may be wet etching or dry etching. The silicon substrate 250 is made thin to, for example, about 20 to 100 μm. Since the silicon substrate 250 directly bonded to the first flow path substrate 210 is made thin by one or more types selected from the group of grinding, etching, and CMP, a variation in the thickness of the second flow path substrate 220 can be suppressed.
Next, as illustrated in
Next, a second liquid flow path forming step ST36 is performed in which the liquid flow path 228 is formed as the flow paths 32a to 32e on the silicon substrate 250 by etching the silicon substrate 250 by using the silicon oxide layer 251 as the etching stop layer, and a mask removing step is performed in which the resist mask RS1 is removed from the second surface 222.
Next, a silicon oxide layer removing step ST37 is performed in which the exposed silicon oxide layer 251 is removed from the flow path component 200. Therefore, the manufacturing method of this specific example includes a silicon oxide layer removing step ST37 of removing the exposed silicon oxide layer 251 after the liquid flow path forming step. The silicon oxide layer removing step ST37 can be performed, for example, by dissolving the exposed silicon oxide layer 251 with an etchant. The exposed silicon oxide layer 251 can be removed from the flow path component 200 by, for example, wet etching using fluorinated acid as an etchant.
As described above, since the silicon oxide layer 251 required for direct bonding can be used as a stop layer in a subsequent step, the manufacturing step of this specific example is efficient. Further, by removing the silicon oxide layer 251 from the liquid flow path 218 of the first flow path substrate 210, the adhesion of the protective film 300 to the liquid flow path 218 is improved in a subsequent protective film forming step.
After the silicon oxide layer removing step ST37, a first protective film forming step ST38 is performed in which the first protective film 301 is formed on the surfaces of the first flow path substrate 210 and the second flow path substrate 220. As the first protective film 301, a material capable of being used for the protective film 300 described above can be used. The first protective film 301 can be formed by one or more film forming methods selected from ALD, CVD, sputtering, and the like, and it is preferable to be formed by ALD which can easily form a film even in a narrow portion of the liquid flow path.
After the first protective film forming step ST38, a nozzle substrate bonding step ST18 is performed in which the thinned second flow path substrate 220 and the nozzle substrate 41 having the nozzle NZ are bonded. The nozzle substrate bonding step ST18 is illustrated in
Of course, for bonding the first flow path substrate 210 and the pressure chamber substrate 33, bonding with the adhesive, the above-mentioned direct bonding, or the like can be used. Further, if the protective substrate 35 illustrated in
In this specific example, since the liquid flow path 228 is formed in the silicon substrate 250 after the first flow path substrate 210 in which the through-holes and grooves forming the flow paths 31a to 31f and the silicon substrate 250 are directly bonded, a complicated flow path such as a horizontal hole can be formed. In this specific example, since the silicon substrate 250 can be made thin after bonding the first flow path substrate 210 and the silicon substrate 250, a support substrate for transporting the flow path component 200 in a subsequent process becomes unnecessary and the cost can be reduced.
As described above, the first flow path substrate 210 and the second flow path substrate 220 are directly bonded to each other without using the adhesive, and after the direct bonding, the second flow path substrate 220 is made thinner than the first flow path substrate 210. Since the first flow path substrate 210 and the second flow path substrate 220 are directly bonded, the second flow path substrate 220 is bonded to the first flow path substrate 210 with high accuracy. Further, since the second flow path substrate 220 is made thin in a state of being supported by the first flow path substrate 210, warpage of the second flow path substrate 220 or the like is prevented, and the thin second flow path substrate 220 having the flow paths 32a to 32e is formed with high accuracy. Therefore, in this specific example, it is possible to manufacture the liquid ejecting head 10 including the flow path component 200 where a thin layer having the liquid flow path is bonded to another layer with high accuracy.
First, a first liquid flow path forming step ST41 is performed in which the liquid flow path 218 is formed as the flow paths 31a to 31f on the silicon substrate to be the first flow path substrate 210. The first flow path substrate 210 is obtained, for example, by forming the liquid flow path 218 by etching the silicon single crystal substrate having a surface index of (110) via a mask.
Next, a second protective film forming step ST42 is performed in which the second protective film 302 is formed on the surfaces of the first flow path substrate 210 and the second flow path substrate 220. As the second protective film 302, a material capable of being used for the protective film 300 described above can be used. That is, the manufacturing method of this specific example includes the second protective film forming step ST42 of forming the protective film 300 including an oxide, a carbide, an oxynitride, or an acid carbide of any element selected from a group of Ta, Zr, Hf, Nb, Si, and Ti on the surface of the first flow path substrate 210 having the liquid flow paths 31a to 31f. The second protective film 302 can be formed by one or more types of film forming methods selected from ALD, CVD, sputtering, and the like, and it is preferable to be formed by ALD which can easily form a film even in a narrow portion of the liquid flow path.
Since it is difficult to form the protective film in the narrow portion of the liquid flow path 218, the protective film is likely to be formed even in the narrow portion of the liquid flow path 218 by forming the second protective film 302 even before bonding the first flow path substrate 210 and the second flow path substrate 220.
Next, as illustrated in
The direct bonding between the first flow path substrate 210 having the second protective film 302 and the second flow path substrate 220 can also be combined in the second specific example or the third specific example.
The printer as the liquid ejecting apparatus includes a copying machine, a facsimile machine, a multifunction device, and the like, in addition to a printing-only machine. Of course, the liquid ejecting apparatus is not limited to the printer.
The liquid ejected from the fluid ejecting head includes a fluid such as a solution in which a solute such as a dye is dissolved in a solvent, and a sol in which solid particles such as pigments and metal particles are dispersed in a dispersion medium. Such liquids include ink, liquid crystal, conductive material, solution of organic substance related to living organism, and the like. The liquid ejecting apparatus includes a color filter manufacturing apparatus for a liquid crystal display or the like, an electrode manufacturing apparatus for an organic EL display or the like, a biochip manufacturing apparatus, a manufacturing apparatus for forming wiring of a wiring substrate, and the like. Here, organic EL is an abbreviation for organic electroluminescence.
As described above, according to the present disclosure, it is possible to provide a technology such as a manufacturing method of a liquid ejecting head including a flow path component in which a thin layer having a liquid flow path is bonded to another layer with high accuracy according to various aspects. Of course, the above-mentioned basic operations and effects can be obtained even with a technology consisting of only the constituent requirements according to the independent claims.
In addition, configurations in which the respective configurations disclosed in the above-mentioned examples are mutually replaced or combinations are changed, respective configurations in which known technologies and the configurations disclosed in the above-mentioned examples are mutually replaced or combinations are changed, and the like can also be implemented. The present disclosure also includes these configurations and the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-048805 | Mar 2020 | JP | national |
