JP2019038126A - Manufacturing method for liquid discharge head - Google Patents

Abstract

To provide a manufacturing method for a liquid discharge head capable of forming a protection film excellent in liquid resistance even at low temperature.SOLUTION: A manufacturing method for a liquid discharge head includes a flow channel 3 of liquid and a substrate 1 disposed with the flow channel 3. The manufacturing method for the liquid discharge head includes: a film formation step of forming a film 10, on a wall surface of the flow channel 3, including a silicon compound selected from a group consisting of SiO, SiOC, and SiN by a CVD method or an ALD method; and a steam plasma processing step for processing the film formed at the film formation step with steam plasma.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a liquid discharge head that discharges liquid such as ink.

  The liquid discharge head is used, for example, as an ink jet print head to discharge ink in an ink jet printing apparatus. A liquid discharge head generally includes a fine discharge port, a flow channel communicating with the discharge port, and a discharge energy generating element that is provided in a part of the flow channel and generates energy for discharging the liquid in the flow channel. Each has a plurality. The flow path is formed by digging a substrate such as a silicon substrate, and may be formed as a through hole penetrating the substrate.

  A substrate such as a silicon substrate is easily eroded by a liquid such as ink used, and the substrate material eluted into the liquid may cause clogging of the discharge port or bending of the discharged liquid, which may cause discharge failure. Further, when the discharge energy generating element is an electrothermal conversion element, the eluted substrate material may contribute to burning. Therefore, the substrate exposed on the inner wall of the flow path is protected with a protective film having liquid resistance so that the substrate is not directly exposed to the liquid. For example, in Patent Document 1, the wall surface of the flow path is covered with a protective film containing a silicon compound such as silicon oxide and silicon nitride.

JP 2006-315191 A

  The protective film is formed by a film forming method using a chemical reaction in a gas phase such as a CVD method or an ALD method. The CVD method and the ALD method are formed by reacting and depositing a raw material silicon compound in a gas phase. On the other hand, the protective film is preferably formed at a relatively low temperature so as not to damage various structures such as elements already formed on the substrate at the time of formation. However, when film formation is performed at a low temperature using a CVD method or an ALD method, the reactivity of the raw material silicon compound may not be sufficient, and an unreacted group may remain in the film, resulting in a film containing impurities. In this case, desired liquid resistance may not be obtained due to the influence of impurities.

  The object of the present invention is to solve the above problems. That is, it is to provide a method for manufacturing a liquid discharge head that can form a protective film having excellent liquid resistance even at low temperatures.

  The method of manufacturing a liquid discharge head according to the present invention is a method of manufacturing a liquid discharge head having a liquid flow path and a substrate provided with the flow path, and includes SiO, SiOC, and SiN on the wall surface of the flow path. A film forming step for forming a film containing a silicon compound selected from the group consisting of CVD and ALD, and a water vapor plasma processing step for processing the film formed in the film forming step with water vapor plasma. It is characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the liquid discharge head which can form the protective film excellent in liquid resistance even at low temperature is provided.

It is a typical perspective view which shows the structural example of a liquid discharge head. FIG. 6 is a cross-sectional view for explaining a process of the method for manufacturing the liquid discharge head according to the first embodiment. It is sectional drawing for demonstrating the process of the manufacturing method of the liquid discharge head concerning 2nd Embodiment. It is sectional drawing for demonstrating the process of the manufacturing method of the liquid discharge head concerning 3rd Embodiment. It is sectional drawing for demonstrating the process of the manufacturing method of the liquid discharge head concerning 4th Embodiment. It is sectional drawing for demonstrating the process of the manufacturing method of the liquid discharge head concerning 5th Embodiment. It is a schematic diagram of the example of a water vapor plasma processing apparatus.

  The present invention relates to a film forming process for forming a film (protective film) containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN on a wall surface of a flow path of a substrate by a CVD method or an ALD method, and a film forming step And a water vapor plasma treatment step of treating the film formed in step 1 with water vapor plasma. According to the manufacturing method of the present invention, even when a film containing the silicon compound is formed at a relatively low temperature by a CVD method or an ALD method and an unreacted group remains in the film, a water vapor plasma is used. By processing, it can be modified into a high-quality protective film having high liquid resistance. This is presumably because unreacted groups remaining in the film are extracted by radicals such as H and OH in the water vapor plasma and the film is oxidized.

  Hereinafter, an embodiment of the present invention will be described by taking an ink jet recording head as an example of a liquid discharge head.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view illustrating a configuration example of a liquid discharge head obtained by the method of manufacturing a liquid discharge head according to the first embodiment.

  The liquid discharge head shown in FIG. 1 has a substrate 1 on which a plurality of discharge energy generating elements 2 that generate energy used for discharging a liquid are formed at a predetermined pitch. The substrate 1 is made of silicon, silicon carbide, silicon nitride, glass (quartz glass, borosilicate glass, alkali-free glass, soda glass), alumina, gallium arsenide, gallium nitride, aluminum nitride, or aluminum alloy. The substrate 1 is preferably a silicon substrate. Examples of the discharge energy generating element 2 include an electrothermal conversion element and a piezoelectric element. On the surface of the substrate 1, a wiring film (not shown) for driving the ejection energy generating element 2 and an anti-cavitation film (not shown) for preventing deterioration of the ejection energy generating element 2 due to cavitation are formed. Yes.

  On the surface of the substrate 1, a flow path forming member 5 for forming a liquid flow path is formed. The flow path forming member 5 includes a top plate 6 in which the discharge port 4 is opened, and a side wall 7 that communicates with the discharge port 4 and forms a pressure chamber 8 that imparts energy generated from the discharge energy generating element 2 to the liquid. ing. The discharge port 4 and the pressure chamber 8 can be regarded as a kind of liquid flow path. The flow path forming member 5 is made of an inorganic compound or resin. Since the fine discharge port 4 and the pressure chamber 8 can be formed with high accuracy, the flow path forming member 5 is preferably formed using a photosensitive resin material. As the photosensitive resin, an epoxy resin is preferable in view of mechanical strength and liquid resistance. A water repellent layer (not shown) may be formed on the surface of the flow path forming member 5 as necessary.

  Between the board | substrate 1 and the flow-path formation member 5, the intermediate | middle layer 9 for improving both adhesiveness is provided. The intermediate layer 9 preferably contains an epoxy resin or a polyamide resin in consideration of the adhesion of the cured product. The intermediate layer 9 is a layer for ensuring the adhesion between the flow path forming member 5 and the substrate 1, and is preferably formed as thin as possible because it does not have other functions. Specifically, the thickness of the intermediate layer 9 is preferably 5.0 μm or less, particularly 1.0 μm or less.

  The substrate 1 is provided with a liquid flow path 3 as a through hole penetrating from the front surface to the back surface of the substrate 1. The liquid supplied from the flow path 3 through the pressure chamber 8 provided with the discharge energy generating element 2 is applied with pressure generated by the discharge energy generating element 2 and discharged as droplets from the discharge port 4. In the liquid discharge head shown in FIG. 1, two flow paths 3 a and 3 b are connected to one pressure chamber 8, and the liquid in the pressure chamber is passed between the outside of the pressure chamber 8 through these two flow paths. It can be circulated. Specifically, the liquid can flow into the pressure chamber 8 through the left channel 3a and flow out from the right channel 3b. For example, when the liquid discharge head according to this embodiment is applied to an ink jet print head, the increase in viscosity of the ink in the discharge ports 4 and the pressure chambers 8 can be suppressed by this liquid flow.

  In such a circulation type liquid discharge head, since the protective film 10 described later is in contact with the flowing liquid for a long time, the protective film 10 is required to have further liquid resistance. The manufacturing method according to the present embodiment can be suitably used for such a circulation type liquid discharge head.

  A protective film 10 that protects the wall surface from liquid erosion is formed on the wall surface of the flow path 3. The protective film 10 is a liquid-resistant film, and specifically includes a silicon compound selected from the group consisting of SiO, SiOC, and SiN. As will be described later, a CVD (Chemical Vapor deposition) method or an ALD (Atomic) method is used. (Layer Deposition) method. As shown in FIG. 1, the protective film 10 may be formed over a region near the opening of the flow path 3 on the surface of the substrate 1.

  2A to 2H are views for explaining the method of manufacturing the liquid discharge head according to the present embodiment for each step with reference to partial cross-sectional views of the liquid discharge head shown in FIG. Hereinafter, a method for manufacturing the liquid discharge head of this embodiment will be described with reference to FIGS.

  First, as shown in FIG. 2A, an intermediate layer 9 is formed on a substrate. A discharge energy generating element 2 is provided on the substrate 1 in advance. The intermediate layer 9 is formed by providing a resin layer to be the intermediate layer 9 on the substrate and then patterning it in a desired shape. The resin layer to be the intermediate layer 9 is a coating method in which a solution containing a predetermined material is applied on a substrate and dried, such as a spin coating method or a slit coating method, and a dry film of the predetermined material. It can be provided on the substrate by a transfer method for transferring onto the substrate. When the intermediate layer 9 is formed thin, for example, when the intermediate layer 9 is desired to be 1.0 μm or less, the coating method is preferable to the transfer method. Thereafter, the flow path 3 penetrating the substrate 1 is formed by etching. Since it is difficult to form a layer serving as the intermediate layer 9 by a coating method on a substrate in which through holes such as the flow channel 3 are formed in advance on the surface of the substrate 1, in this embodiment, the flow channel 3 Prior to the formation, the intermediate layer 9 is formed.

  Next, as shown in FIG. 2B, a film containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN is formed as a protective film 10 on the substrate by a CVD method or an ALD method (film). Forming step). The protective film 10 is formed over the entire substrate including the wall surface of the flow path 3.

  The CVD method is a method of forming a film by decomposing a raw material compound in a gas phase and depositing it on the surface of a target substrate. On the other hand, the ALD method is a method in which a raw material compound is adsorbed on the surface of a target substrate and then reacted to form a film one by one at the atomic level. First, a gas containing a raw material compound for a film is fed into a vacuum chamber, and after about 1 atomic layer is adsorbed on the heated substrate surface, the unreacted raw material compound is exhausted. When the substrate surface is covered with the adsorbed raw material compound, no further adsorption of the raw material compound occurs, so that a state in which the raw material compound is adsorbed to a certain extent can be created. Next, a reactive gas such as water, oxygen, ozone, and ammonia is introduced to cause a chemical reaction in the adsorbed raw material compound, which is converted into a desired compound, and then the reactive gas is exhausted. In this way, the ALD method is a method of repeating a cycle in which a raw material compound is adsorbed one atomic layer at a time and reacted. The ALD method can form a high-quality film with fewer film defects than a CVD method with good followability even for a complicated structure. In addition, the ALD method can easily form a film at a relatively low temperature.

As the raw material compound used for forming the protective film 10, it is preferable to use a silicon compound having a halogeno group because it is easy to form a film at a low temperature. The halogeno group becomes a hydrogen halide by radicals such as H and OH in the water vapor plasma and is extracted from the protective film 10 and easily detached from the substrate. Therefore, when a silicon compound having a halogeno group is used, it is possible to form the protective film 10 with fewer unreacted groups and higher liquid resistance. Examples of the halogeno group include a fluoro group, a chloro group, a bromo group, and an iodo group, and a chloro group is preferred because it is particularly easily available. As a raw material silicon compound, tetrachlorosilane, hexachlorodisilane, tetrachlorodialkyldisilane [(CH ₃ (CH ₂ ) _n ) ₂ Si ₂ Cl ₄ ], dichlorotetraalkyldisilane [(CH ₃ (CH ₂ ) _n ) ₄ Si ₂ Cl ₂ ], and bistrichlorosilylalkane [Si ₂ (CH ₂ ) _n Cl ₆ ]. n is an integer of 1-4. Among these, hexachlorodisilane is preferable because the protective film 10 having a high density can be formed.

  As the reactive gas, pure water or ammonia is preferable. Further, when depositing each gas, the catalyst may be deposited on the substrate at the same time. Suitable materials for the catalyst include pyridine, picoline, and aniline.

  The deposition temperature of the protective film 10 is preferably a low temperature of 250 ° C. or less, particularly 100 ° C. or less in order to suppress damage to structures such as elements and intermediate layers already formed on the substrate. Further, considering the reactivity of the raw material silicon compound, it is preferably 60 ° C. or higher, particularly 70 ° C. or higher.

  Next, as shown in FIG. 2C, a resist 11 is provided on the surface of the substrate 1. The resist 11 serves as a mask pattern when the protective film 10 is etched. The protective film 10 only needs to be formed on the wall surface of the flow path 3, and unnecessary portions on the other substrate, for example, the wiring film and the protective film 10 on the intermediate layer 9 are removed by etching. The resist 11 is a film-like resist containing a photosensitive resin, and is formed on the surface of the substrate 1 by a tenting method. As the photosensitive resin, a positive photosensitive resin or a negative photosensitive resin can be used. In particular, the photosensitive resin is preferably a material that can be patterned using a stepper from the viewpoint of alignment accuracy, and more preferably a material that can be patterned with the most general-purpose i-line (365 nm). Specifically, a positive photoresist composed of a novolak resin and a naphthoquinonediazide derivative is preferable. Examples of such a positive photoresist include “OFPR800” (trade name) and “THMR ip5700” (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd.

  Next, as shown in FIG. 2D, a mask pattern 11a is formed by exposing and developing the resist 11 with an exposure apparatus (mask forming step). The exposure light is preferably i-line.

Next, as shown in FIG. 2E, the protective film 10 is patterned into a desired shape by wet etching using the mask pattern 11a as a mask (patterning step). The wet etching is preferably performed using an acid solution having a high etching rate with respect to the protective film, such as buffered hydrofluoric acid, using a spin etcher. The patterning may be performed by dry etching such as reactive ion etching using CF ₄ gas.

  Next, as shown in FIG. 2F, the mask pattern 11a is peeled off and removed. The step of removing the mask pattern 11a is preferably performed by a lift-off method, a method of impact peeling by wet etching, or a method of dissolving and removing in consideration of damage to the wiring film and the intermediate layer 9 which are the underlying layers. In particular, it is preferable to remove the mask pattern 11a by dissolving it with a general resist removing solution. An example of such a resist removing solution is “Rim Bar 1112A” (trade name) manufactured by Rohm and Haas Electronic Materials Co., Ltd. Thereafter, if necessary, the substrate 1 may be dried by post-baking or the like in order to remove moisture in the flow path 3 of the substrate 1.

  Next, as shown in FIG. 2G, the protective film 10 is treated with water vapor plasma (water vapor plasma treatment step). Specifically, the substrate 1 is installed in a water vapor plasma processing apparatus to be described later, and the surface of the protective film 10 is treated with water vapor plasma by exposing the entire substrate to water vapor plasma. Radicals such as H and OH in the water vapor plasma pull out unreacted functional groups remaining in the protective film 10. As a result, the high-quality protective film 10 with few unreacted functional groups can be formed. Further, the O radicals slightly present in the water vapor plasma also has an action of cleaning the surface of the intermediate layer 9 by impact on the surface of the intermediate layer 9.

The generation conditions and processing conditions of the water vapor plasma can be adjusted as appropriate. Preferred examples of conditions for generating water vapor plasma are given below.
H ₂ O gas pressure: 80 Pa to 130 Pa
H ₂ O gas flow rate: 100 sccm to 300 sccm
Microwave output: 1000W to 3000W
Microwave frequency: 2.45 GHz
The treatment time with water vapor plasma is preferably 2 min or more and 60 min or less. The treatment temperature with water vapor plasma is preferably 60 ° C. or higher and 250 ° C. or lower. By setting the treatment temperature by water vapor plasma within this range, damage to structures such as elements and intermediate layers already formed on the substrate can be suppressed. In order to keep the processing temperature low, the cooling step and the processing step may be performed intermittently.

An example of the water vapor plasma processing apparatus used in this embodiment is shown in FIG. The water vapor plasma processing apparatus 21 uses surface wave plasma (SWP; Surface Wave Plasma) generated by propagating microwaves along the surface of the quartz 22 and excites the gas flowing between the quartz 22 and the aluminum plate 23. Let And the protective film 10 in the board | substrate 1 is processed by the downflow of the gas. Since the substrate 1 exposes the protective film 10 in the flow path 3, which is a through-hole, to water vapor plasma, the substrate 1 is floated by the pins 24 from the support base 25 so that H ₂ O gas can enter from the back side of the substrate 1. . An aluminum plate 23 having a plurality of small holes is provided between the quartz 22 and the substrate 1. Since the aluminum plate 23 is grounded and traps ions generated in the chamber, only neutral radicals can be incident on the substrate 1. Since ions in the plasma have anisotropy, there is a possibility that variations in the modification of the protective film may occur. However, the protective film is uniformly modified by such an apparatus configuration. Further, by trapping ions, the etching of the quartz 22 is suppressed and a high modification rate can be maintained.

  The protective film 10 after being treated with the water vapor plasma preferably has a concentration gradient in which the halogen atom content decreases along the depth direction from the surface thereof. That is, it is preferable that the surface of the protective film 10 is modified so that the halogen atom content is low, and the region of the protective film 10 on the substrate side remains unmodified. The surface of the protective film 10 is preferably modified so that the liquid resistance is high. On the other hand, the modified protective film 10 has a slower etching rate and a lower patterning property than the protective film 10 before the modification. The surface of the substrate 1 has unevenness due to the ejection energy generating element 2, the wiring film, and the like. When patterning the protective film 10 as described later, the unevenness of the protective film 10 on the substrate 1 side is formed. Residues are likely to form in the stepped portion. Therefore, in order to maintain the etching rate in a region near the surface of the substrate 1 of the protective film 10, it is preferable that the region is not so modified. The degree of modification of the protective film 10 can be adjusted by the water vapor plasma processing conditions. Specifically, the halogen atom content on the surface of the protective film 10 is preferably 0.1% or less, particularly 0.0%. The halogen atom content in the surface of the protective film 10 on the substrate side is preferably 0.2% or more and 0.5% or less.

  Next, as shown in FIG. 2H, a flow path forming member 5 is formed on the surface of the substrate 1. First, a dry film resist in which a photosensitive resin material is applied on a film substrate is bonded onto the surface of the substrate 1. The photosensitive resin is preferably an epoxy resin. Then, the side wall 7 of the flow path forming member 5 is patterned by exposing and developing the dry film resist. Next, the top plate 6 of the flow path forming member 5 is patterned using the same dry film resist. Finally, the non-exposed portion is developed to form the discharge ports 4 and the pressure chambers 8 to complete the liquid discharge head.

  In this embodiment, the water vapor plasma treatment process of the protective film 10 is performed after the patterning process of the protective film 10. When a part of the protective film 10 is removed by wet etching in the patterning process of the protective film 10, a residue may be generated. According to the manufacturing method of the present embodiment, since the water vapor plasma treatment process is performed after the patterning process of the protective film 10, the residue is easily removed by the water vapor plasma treatment process.

(Second Embodiment)
3A to 3H are views for explaining the method of manufacturing the liquid ejection head according to the second embodiment for each step. The difference of the second embodiment from the first embodiment is that the water vapor plasma treatment process of the protective film 10 is performed not after the patterning process of the protective film 10 but before the patterning process after the formation process of the protective film 10. is there. That is, in the second embodiment, the water vapor plasma treatment of the protective film 10 is performed with the protective film 10 covering the entire surface of the substrate 1.

  The second embodiment is particularly advantageous when the wiring film 13 is present below the protective film 10. The wiring film 13 is usually composed of a metal film or a laminate of metal films. Specific examples of the metal film include Mo, Ti, W, Ni, Ta, Cu, Al, Cr, and alloys thereof. Since these metal films are hydrogen embrittled, it is not preferable to be exposed to water vapor plasma. According to this embodiment, since the protective film 10 is exposed to water vapor plasma in a state where the wiring film 13 is not exposed, the protective film 10 can be processed without altering the wiring film 13.

  Hereinafter, a method for manufacturing the liquid discharge head will be described with reference to FIGS. In the following description, points different from the first embodiment will be mainly described.

  First, as shown in FIG. 3A, the intermediate layer 9 is formed on the surface of the substrate 1. The substrate 1 is provided with a flow path 3, a discharge energy generating element 2 and a wiring film 13 in advance. Next, as shown in FIG. 3B, a protective film 10 is formed over the substrate. Next, as shown in FIG. 3C, the surface of the protective film 10 is treated with water vapor plasma. Thereafter, similarly to the first embodiment, the liquid discharge head is completed by patterning the protective film 10 to form the flow path forming member 5.

(Third embodiment)
4A to 4H are views for explaining the manufacturing method of the liquid ejection head according to the third embodiment for each step. In the third embodiment, similarly to the second embodiment, the water vapor plasma treatment process of the protective film 10 is performed after the protective film 10 is formed and before the patterning process. The difference from the second embodiment is that the water vapor plasma treatment process for the protective film 10 is performed after the mask forming process for forming the mask pattern 11a for patterning the protective film 10 and before the patterning process for the protective film 10. It is. Similarly to the second embodiment, the third embodiment exposes the protective film 10 to water vapor plasma in a state where the wiring film 13 is not exposed. Therefore, the protective film 10 is modified without altering the wiring film 13. be able to.

(Fourth embodiment)
FIGS. 5A to 5H are views for explaining the method of manufacturing the liquid discharge head according to the fourth embodiment for each step. In the fourth embodiment, the protective film 10 has two layers, and the water vapor plasma treatment process of the protective film 10 is performed after the formation process of the protective film 10 and before the patterning process as in the second embodiment. The protective film 10 includes a first protective film (first film) 10a and a second protective film (second film) 10b provided under the first protective film 10a. The first protective film 10a contains a compound selected from the group consisting of SiO, SiOC, and SiN, like the protective film 10 of the first embodiment. The second protective film 10b is a protective film having higher liquid resistance than the first protective film 10a, and is made of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti. It preferably contains an oxide, an oxycarbide, or a nitride. By making the protective film 10 have such a two-layer structure, the wall surface of the flow path 3 can be more effectively protected from the liquid.

  Hereinafter, a method for manufacturing the liquid discharge head will be described with reference to FIGS. In the following description, points different from the above-described embodiment will be mainly described.

  First, as shown in FIG. 5A, the intermediate layer 9 is formed on the surface of the substrate 1. The substrate 1 is provided with a discharge energy generating element 2 and a flow path 3 in advance.

  Next, as shown in FIG. 5B, a second protective film 10b is formed over the substrate. The second protective film 10b preferably contains an oxide, oxycarbide, or nitride of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti. Furthermore, the second protective film 10b preferably includes an oxide of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti, and more preferably includes TiO. The second protective film 10b can be formed by a CVD method or an ALD method. The second protective film 10b is preferably formed by the ALD method because it can form a high-quality and high-density film with few film defects.

  As a raw material compound used for forming the second protective film 10b, a compound having a halogeno group is preferably used because film formation at a low temperature is easy. Examples of the halogeno group include a fluoro group, a chloro group, a bromo group, and an iodo group, and a chloro group is particularly preferable.

  The reactive gas is preferably pure water. Further, when depositing each gas, the catalyst may be deposited on the substrate at the same time. Suitable materials for the catalyst include pyridine, picoline, and aniline.

  The film formation temperature of the second protective film 10b is 250 ° C. or lower, particularly 100 ° C. or lower in order to suppress damage to structures such as elements and intermediate layers already formed on the substrate. Is preferred. In consideration of the reactivity of the raw material compound, it is preferably 60 ° C. or higher, particularly 70 ° C. or higher.

  Next, as shown in FIG. 5C, a first protective film 10a containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN is formed on the second protective film 10b by a CVD method or an ALD method. To form.

  Next, as shown in FIG. 5D, the protective film 10 is treated with water vapor plasma. Specifically, the surface of the first protective film 10a is treated with water vapor plasma by exposing the entire substrate to water vapor plasma. The oxide, oxycarbide, or nitride of the metal element contained in the first protective film 10a below the second protective film 10b is hydrogen embrittled. Also in the present embodiment, as in the second embodiment, the first protective film 10a is exposed to water vapor plasma in a state where the first protective film 10a is not exposed. Therefore, the first protective film 10a is not altered and the first protective film 10a is not altered. The protective film 10a can be modified.

  Thereafter, similarly to the first embodiment, the liquid ejection head is completed by patterning the protective film 10 using the mask pattern 11a to form the flow path forming member 5.

(Fifth embodiment)
6A to 6H are views for explaining the method of manufacturing the liquid ejection head according to the fifth embodiment for each step.

  In the fifth embodiment, as in the fourth embodiment, the protective film includes a first protective film 10a containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN, Ta, Zr, and Hf. , Nb, and Ti, and a second protective film 10b containing an oxide, oxycarbide, or nitride of any metal element selected from the group consisting of Ti. However, in the fifth embodiment, unlike the fourth embodiment, the positions of the first protective film 10a and the second protective film 10b are opposite, that is, the second protective film on the first protective film 10a. 10b is provided.

  In the present embodiment, the first protective film 10a is not directly exposed to the water vapor plasma, but depending on the conditions, hydrogen radicals enter from the second protective film 10b that has become hydrogen embrittled to modify the first protective film 10a. Can do.

  By adopting a configuration in which the second protective film 10b is an upper layer, the second protective film 10b becomes hydrogen embrittled and the liquid resistance is also lowered. Therefore, from the viewpoint of liquid resistance, it is preferable that the second protective film 10b is a lower layer so that the second protective film 10b is not exposed to plasma as in the fourth embodiment. However, when both are patterned by wet etching, this embodiment has an advantage that the second protective film 10b can be patterned with higher accuracy than the case where the second protective film 10b is a lower layer.

  The first protective film 10a usually has a higher etching rate than the second protective film 10b due to the characteristics of the material. Therefore, if the first protective film 10a is a lower layer, the first protective film 10a may be over-etched, and damage may be caused to a wiring film or the like provided further below the first protective film 10a. By using the second protective film 10b as an upper layer as in the present embodiment, the second protective film 10b is exposed to water vapor plasma, thereby becoming hydrogen embrittled and improving the etching rate. For example, when a laminated film composed of a TiO film and an SiO film is etched with buffered hydrofluoric acid, the selection ratio between the TiO film and the SiO film is approximately 1:70. When the water vapor plasma treatment is performed with the TiO film stacked on the SiO film, the etching rate of the TiO film is improved and the selectivity can be improved up to about 1: 3. As a result, even when patterning is performed by wet etching, the protective film 10 can be patterned with high accuracy and damage to the wiring film or the like can be suppressed.

  In the present embodiment, the water vapor plasma treatment process of the protective film 10 may be performed before the patterning process of the protective film 10. The water vapor plasma treatment process of the protective film 10 is particularly a mask forming process for forming a mask pattern 11a for patterning the protective film 10 just before the patterning process of the protective film 10, that is, as in the third embodiment. Thereafter, it is preferably performed before the patterning step of the protective film 10.

  Hereinafter, a method for manufacturing the liquid discharge head will be described with reference to FIGS. In the following description, points different from the above-described embodiment will be mainly described.

  First, as shown in FIG. 6A, the intermediate layer 9 is formed on the surface of the substrate 1. The substrate 1 is provided with a discharge energy generating element 2 and a flow path 3 in advance.

  Next, as shown in FIG. 6B, a first protective film 10a containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN is formed on the substrate by a CVD method or an ALD method.

  Next, as shown in FIG. 6C, on the first protective film 10a, an oxide or acid of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti. A second protective film 10b containing carbide or nitride is formed.

  Next, as shown in FIG. 6D, a resist 11 is provided on the surface of the substrate 1.

  Next, as shown in FIG. 6E, the resist 11 is exposed by an exposure device and developed to form a mask pattern 11a.

  Next, as shown in FIG. 6F, the protective film 10 is treated with water vapor plasma. Specifically, the first protective film 10a and the second protective film 10b are treated with water vapor plasma by exposing the entire substrate to water vapor plasma.

  Next, as shown in FIG. 6G, the first protective film 10a and the second protective film 10b are patterned into desired shapes by performing wet etching using the mask pattern 11a as a mask.

  Next, as shown in FIG. 6H, the mask pattern 11a is peeled off and removed.

  Next, as shown in FIG. 6I, the liquid discharge head is completed by forming the flow path forming member 5 on the surface of the substrate 1.

  First, as shown in FIG. 2A, an intermediate layer 9 made of polyamide resin was formed on the surface of the substrate 1 in which the flow path 3 was formed as a through hole.

  Next, as shown in FIG. 2B, a protective film 10 was formed over the entire substrate 1 including the wall surface of the flow path 3 by the ALD method. The protective film 10 was formed by alternately supplying HCD and pure water using hexachlorodisilane (HCD) as a precursor, pure water as a reactive gas, and pyridine as a catalyst. The film forming temperature was 75 ° C.

  Next, as illustrated in FIG. 2C, a resist 11 was formed over the protective film 10. The resist 11 was formed by sticking a film of a photosensitive resin material to the surface side of the substrate 1 by a tenting method. As the photosensitive resin material, “OFPR800” (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was used.

  Next, as shown in FIG. 2D, the resist 11 was exposed and developed by i-line, thereby forming a mask pattern 11a for leaving the protective film 10 on the wall surface of the flow path 3.

  Next, as shown in FIG. 2E, the protective film 10 was patterned using the mask pattern 11a as a mask. Patterning was performed by wet etching only from the surface side of the substrate 1. The wet etching process was performed using a spin etcher and buffered hydrofluoric acid.

  Next, as shown in FIG. 2F, the mask pattern 11a was removed by “Rim Bar 1112A” (trade name) manufactured by Rohm & Haas Electronic Materials Co., Ltd. Thereafter, in order to remove moisture in the flow path 3 of the substrate 1, post-baking was performed.

Next, as shown in FIG. 2G, the protective film 10 was processed by exposing the substrate 1 to water vapor plasma under a vacuum of 120 Pa in the water vapor plasma processing apparatus shown in FIG. Since the temperature of the substrate 1 is increased by the water vapor plasma treatment, the discharge step and the cooling step by natural cooling are repeatedly performed so that the temperature of the substrate 1 is maintained at 200 ° C. or lower. One discharge process was performed for 2 minutes, and was performed intermittently for a total of 60 minutes. Pure water was used as the H ₂ O gas source and introduced into the chamber at a gas flow rate of 200 sccm. H ₂ O gas was turned into plasma using microwaves of 2800 W and 2.45 GHz.

  Finally, a flow path forming member 5 was formed as shown in FIG. 2 (H) to manufacture a liquid discharge head.

  The atomic composition of the protective film 10 before and after the water vapor plasma treatment step was measured by ESCA (Electron Spectroscopy for Chemical Analysis) which is X-ray electron spectroscopy. The atomic composition of the protective film 10 was an average value of values measured every 10 nm in the thickness direction from the surface of the protective film. As a result, the chlorine content before the water vapor plasma treatment was 0.45%, but decreased to 0.20% after the water vapor plasma treatment step. Further, the chlorine content of the protective film 10 after the water vapor plasma treatment step had a gradient in the depth direction, and was 0.0% at the surface layer and 0.25% at a depth of 30 nm from the surface layer.

  Further, the obtained liquid discharge head was immersed in 20 ml of 60 ° C. ink (Canon) as an acceleration test, and the thickness of the protective film 10 after 5 hours was measured with an ellipso apparatus (FE7000L, trade name) manufactured by Otsuka Electronics. Then, the reduction rate [nm / min] of the protective film was obtained. As a comparison, a liquid discharge head manufactured without performing the water vapor plasma treatment process was used. As a result, the reduction rate of the protective film formed without performing the water vapor plasma treatment was 70.6 nm / min, whereas the reduction rate of the protective film subjected to the water vapor plasma treatment was 36.7 nm / min.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Discharge energy generating element 3 Flow path 4 Discharge port 5 Flow path forming member 9 Intermediate layer 10 Protective film 10a First protective film (first film)
10b Second protective film (second film)
13 Wiring film

Claims (16)

A liquid discharge head manufacturing method comprising a liquid flow path and a substrate provided with the flow path,
Forming a film containing a silicon compound selected from the group consisting of SiO, SiOC, and SiN on the wall surface of the flow path by a CVD method or an ALD method;
A water vapor plasma treatment step of treating the film formed in the film formation step with water vapor plasma;
A method of manufacturing a liquid discharge head, comprising:   The method of manufacturing a liquid ejection head according to claim 1, wherein the film is formed by an ALD method in the film formation step.   The method of manufacturing a liquid discharge head according to claim 2, wherein a silicon compound having a halogeno group is used as a raw material in the film forming step.   The method of manufacturing a liquid discharge head according to claim 3, wherein the halogen atom content in the surface of the film treated with the water vapor plasma is 0.1% or less.   5. The method of manufacturing a liquid ejection head according to claim 3, wherein the film treated with the water vapor plasma has a concentration gradient in which a halogen atom content rate decreases in a depth direction from the surface.   The method of manufacturing a liquid ejection head according to claim 1, wherein the film is formed at 250 ° C. or lower in the film formation step. And a mask forming step of forming a mask on the film formed in the film forming step; and a patterning step of patterning the film using the mask.
The method for manufacturing a liquid ejection head according to claim 1, wherein the water vapor plasma processing step is performed after the patterning step. And a mask forming step of forming a mask on the film formed in the film forming step; and a patterning step of patterning the film using the mask.
The method for manufacturing a liquid ejection head according to claim 1, wherein the water vapor plasma processing step is performed before the patterning step. And a masking step of forming a mask on the film formed in the film forming step; and a patterning step of patterning the film using the mask.
The method of manufacturing a liquid ejection head according to claim 1, wherein the water vapor plasma treatment step is performed after the mask formation step and before the patterning step.   The method of manufacturing a liquid ejection head according to claim 7, wherein the film is patterned by wet etching in the patterning step. The liquid discharge head includes a flow path forming member on the substrate, and an intermediate layer including a resin between the flow path forming member and the substrate,
The method of manufacturing a liquid ejection head according to claim 1, wherein the intermediate layer is provided on the substrate in advance before the film forming step.   The liquid discharge head includes: a discharge energy generating element that generates energy for discharging liquid on the substrate; and a pressure chamber including the discharge energy generating element therein, and the liquid in the pressure chamber is the pressure The method of manufacturing a liquid ejection head according to claim 1, wherein the liquid ejection head is circulated between the outside of the chamber. The liquid discharge head includes, on the substrate, a discharge energy generating element that generates energy for discharging a liquid, and a wiring film for driving the discharge energy generating element,
The method of manufacturing a liquid ejection head according to claim 1, wherein the wiring film is provided on the substrate in advance before the film forming step.   The method of manufacturing a liquid discharge head according to claim 13, wherein the wiring film is a metal film containing Mo, Ti, W, Ni, Ta, Cu, Al, Cr, and alloys thereof. The liquid discharge head further includes a second film below the first film, when the film formed in the film forming step is the first film.
The second film according to any one of claims 1 to 14, wherein the second film includes an oxide, an oxycarbide, or a nitride of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti. A manufacturing method of a liquid discharge head given in the paragraph. The liquid discharge head further includes a second film on the first film, when the film formed in the film forming step is a first film.
The second film according to any one of claims 1 to 14, wherein the second film includes an oxide, an oxycarbide, or a nitride of any metal element selected from the group consisting of Ta, Zr, Hf, Nb, and Ti. A manufacturing method of a liquid discharge head given in the paragraph.

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