Patent Application
20190255831
The present invention relates to a method of attaching a resin film and a method of manufacturing a liquid ejection head by using the attaching method.
Liquid ejection recording apparatuses (liquid ejection apparatuses) represented by ink jet recording apparatuses carry out recording by ejecting recording liquid droplets to force them to fly from ejection orifices of their liquid ejection head and land onto a recording medium.
The constitution of such a liquid ejection head will next be described. As shown in
The ejection orifice forming member 20 includes bubbling chambers 10 each of which stores an ink and generates an air bubble therein by means of an energy generating element 2 and a minute ejection orifice 5 for ejecting ink droplets. The silicon substrate 1 is, in addition, equipped with a liquid supply path or liquid supply paths each running through the substrate from the surface to the back surface thereof and each liquid supply path is comprised of a plurality of ink supply ports 6 (individual supply ports) that are opened on the surface side and a common liquid chamber 3 that is associated with the ink supply ports and is opened on the back surface side of the substrate. The silicon substrate 1 has, on the bottom surface (back surface) side thereof, a flow path member 7 serving as a lid member of the common liquid chamber 3. Ink is supplied to the bubbling chamber 10 from the outside through the common liquid chamber 3 and the ink supply ports 6.
The ink, after filling the bubbling chamber 10 therewith, is pushed out in a direction almost orthogonal to the silicon substrate by air bubbles produced by film boiling caused by the ejection energy generating element 2 and ink droplets are ejected from the ejection orifices 5.
The ejection orifice forming member 20 having such a constitution can be obtained, for example, by attaching a resist film to a silicon substrate and forming the bubbling chambers 10 and the ejection orifices 5 by photolithography. The flow path member 7 on the back surface side of the silicon substrate 1 can be obtained similarly by attaching a resist film thereto and making the opening portion(s) by photolithography.
Japanese Patent Application Laid-Open No. 2008-000963 discloses a method of, during formation of a precise fine space or spaces, providing a film serving as a top board on a substrate having a precise fine recess or recesses while controlling the pressure, per unit contact area, of a contact portion or portions between the substrate and the film to be constant. According to this document, the film can be prevented from entering the precise fine recess or recesses. There is also disclosed a method of fixing, as a film, a dried resist film by applying heat and pressure by a lamination method and forming a precise fine space by photolithography including exposure, PEB and development.
According to Japanese Patent Application Laid-Open No. 2008-000963, the dried resist film (resin film) is fixed to the substrate by applying heat and pressure by a lamination method and is thus provided on (or attached onto) the substrate. In this case, the film is heated by both a stage which heats the substrate and a roller which heats the film. When the temperature of the resist film is too low, the film does not adhere to the substrate. On the contrary, when the temperature is too high, the film thus laminated inevitably has a deteriorated surface shape. Thus, there occurs a trade-off problem. In addition, the dried resist film has a resin film on a base film. Usually, after the surface of the resin film to be bonded to the substrate is bonded under pressure to the substrate from above the base film by a roller or the like, the base film is released. At this time, when the temperature at the time of bonding is also high on the surface of the resin film to be released from the base film, that is, the surface of the resin film opposite to the bonded surface, the resin film may have a deteriorated surface shape after releasing. When the dried resist film is used for the formation of a flow path member or an ejection orifice forming member of a liquid ejection head, such insufficient attachment or deterioration in surface shape may particularly become a problem.
In one aspect of the invention, there is provided a method of attaching a resin film laminated on a support film onto a surface of a substrate having a pattern of unevenness by means of a roller. The method includes a step of placing the substrate on a stage with the surface side up and a step of placing the resin film so as to face the surface of the substrate placed on the stage and scanning the surface with the roller while pressing the resin film against the surface from the side of the support film to bring the film into contact with the surface and stick the resin film to the surface of the substrate by means of the roller. In this method, a surface temperature of the stage and a surface temperature of the roller are set to form a temperature gradient such that a temperature of a first surface of the resin film to be attached to the surface of the substrate becomes a softening temperature of the resin film or higher and a temperature of a second surface of the resin film to be brought into contact with the support film becomes lower than the softening temperature of the resin film.
In the other aspect of the invention, there is provided a method of manufacturing a liquid ejection head by using the above-described method of attaching a resin film.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An object of the invention is to provide a resin film attaching method capable of attaching a resin film to a substrate reliably and at the same time, attaching without causing a change in the surface shape of both surfaces of the resin film and a method of manufacturing a liquid ejection head by using the resin film attaching method.
Embodiments of the invention will hereinafter be described referring to some drawings.
The dry film 40 can be obtained, for example, by applying a material of the resist film 35 onto the base film 27 by spin coating, slit coating, or the like and solidifying it into a film having a thickness of from 5 μm to 200 μm. As the material of the resist film 35, for example, a negative photosensitive resin can be used. Examples of it include negative photosensitive resins making use of a radical polymerization reaction and negative photosensitive resins making use of a cationic polymerization reaction. The negative photosensitive resins may be used either singly or in combination as a mixture. If necessary, an additive and the like may be added as needed. As the negative photosensitive resin, usable are commercially available ones such as “SU-8 series” and “KMPR-1000” (each, trade name; product of Nippon Kayaku) and “TMMR 52000” (product of Tokyo Ohka Kogyo).
As the base film 27, a film made of an olefin resin such as PET, polyimide, polyethylene or polypropylene is used. The surface of the base film 27 on which the resist film 35 is to be formed may be subjected to release treatment to facilitate release of it from the resist film 35. A commercially available product in the form of a dry film such as “TMMF 52000” series (trade name; product of Tokyo Ohka Kogyo) may be used. Such a commercially available dry film has, on the surface to be attached, a cover film and this cover film is used after being released at the time of attachment.
When the dry film 40 is attached to the substrate by pressing and bringing it into contact therewith (pressing against the substrate) by means of a roller as shown in
The second surface (on the side of the interface Y) of the resist film 35 which will be a surface of the structure obtained after release of the base film 27 has preferably a temperature lower than the softening temperature in order to prevent the second surface from softening and thereby flowing to cause deterioration of the surface shape. In other words, the surface temperature of the roller 8 and the surface temperature of the stage 9 are preferably set to show a gradual decrease from the side of the stage 9 toward the side of the roller 8 inside the resist film 35. More specifically, the surface temperature of the roller 8 and the surface temperature of the stage 9 are preferably set to form a temperature gradient at which the temperature of the first surface of the resist film 35 becomes the softening temperature of the resin film or higher and the temperature of the second surface of the resist film becomes lower than the softening temperature of the resin film. In short, conditions such as the surface temperature of the roller 8 and the surface temperature of the stage 9 are preferably set so that the temperature profile crosses the softening temperature inside the resist film 35.
As one method to realize the above-described state, the surface temperature of the stage 9 which is contact with the substrate 1 is made higher than the softening temperature of the resist film 35. When the resist film 35 has a softening temperature of from 35° C. to 45° C. (more specifically, 40° C.), the surface temperature of the material is set at, for example, from 45° C. to 80° C. and the surface temperature of the roller 8 near the second surface of the resist film 35 is set lower than the softening temperature, though depending on the material. It is, for example, from −15° C. to 35° C. The surface temperature of the stage 9 is preferably higher by 5° C. or more than that of the roller 8. The advantage of the present embodiment is exhibited more when a substrate having a low surface energy and a pure water contact angle of, for example, 60° or more is used as the substrate 1. An influence of a roller pressure is presumed to be relatively small.
As in First Embodiment, a substrate 1 subjected to precise fine processing was placed on a stage 9 (
When the resist film 35 is attached to the substrate 1 subjected to precise fine processing, a base film 27 made of a material having a low thermal conductivity is preferred. More specifically, the base film 27 has preferably a thermal conductivity of 0.3 W/m·K or less. Examples of the material of the base film include PET, polyimide and hydrocarbon-based films. The base film is preferably as thick as, for example, from 50 to 500 μm. As a result, as shown in
A method of manufacturing a liquid ejection head will next be described as one using example of the method of attaching a resin film of the invention, but the invention is not limited only to the manufacture of a liquid ejection head.
The liquid ejection head shown in
First, as shown in
A dry film 40 obtained by applying an epoxy resin (including “N-695”, product of Dainippon Ink) which would be a photosensitive resin (resin film) 22 onto a base film 23 made of PET by spin coating was prepared in advance. The respective sensitivities of the first photosensitive resin 22 and a second photosensitive resin 24 which will be described later have already been adjusted to permit selective exposure patterning. The first photosensitive resin 22 had a softening temperature of 70° C. and had a thickness of 15 μm.
Next, as shown in
Then, as shown in
A dry film 41 obtained by applying an epoxy resin (including “157S70”, product of Japan Epoxy Resin (JER) as a part of Mitsubishi Chemical) which would be a second photosensitive resin 24 onto a PET film which would be a base film 25 was prepared in advance. As shown in
Then, as shown in
A dry film 42 obtained by applying TMMF (product of Tokyo Ohka Kogyo) which would be a third photosensitive resin (resin film) 26 onto a base film 27 made of PET was prepared in advance. The third photosensitive resin 26 has a softening temperature of about 40° C.
As shown in
Then, as shown in
It was confirmed that with respect to the back surface of the substrate 11, the third photosensitive resin 26 adhered sufficiently to the substrate 11 without floating after the base film 27 was released. With respect to the surface shape of the third photosensitive resin 26 (the uppermost surface in
Table 1 shows the evaluation results of the adhesiveness of the third photosensitive resin 26 (dry film 42) and the surface shape thereof obtained by making a test while changing, among the above-described attachment conditions, only those for the third photosensitive resin, that is, the respective surface temperatures of the stage 8 and the roller 9. Evaluation criteria for adhesiveness were as follows: A: no floating (good), B: floating at several places (acceptable) and C: floating at more than ten places (unacceptable). Evaluation criteria for surface shape (unevenness amount) were as follows: A: 10 μm or less (good), B: from 10 to 15 μm (acceptable) and C: 15 μm or more (unacceptable).
It is apparent from Table 1 that the roller surface temperature higher than the softening temperature of the third photosensitive resin, that is, 40° C. (data at 45° C. or higher), deteriorates the surface shape. It is also apparent that the stage surface temperature lower than the softening temperature, that is, 40° C. (data at 35° C. or lower) deteriorates the adhesiveness to the substrate. This has revealed that it is preferred to set the roller surface temperature at the softening temperature or lower and the stage surface temperature at the softening temperature or higher. For example, when a resin film having a softening temperature of 40° C. is used, it is preferred to set the roller surface temperature to from 30° C. to 40° C. and the stage surface temperature to from 40° C. to 50° C.
By Si deep etching of a substrate 11 provided with an ejection energy generating element 12 as in Example 1, a common liquid chamber 13 and an ink supply port 16 were formed and further, an ejection orifice forming member 20 was formed. Then, in a step of laminating a third photosensitive resin layer 26 with the back surface of the substrate 11, the third photosensitive resin layer was attached under the conditions of a stage surface temperature of 45° C., a roller surface temperature of 45° C., a roller pressure of 0.2 MPa and a roller speed of 10 mm/s. Although the roller surface temperature was 45° C. and was higher than the softening temperature of the third photosensitive resin layer 26, not only adhesiveness to the substrate but also flatness could be secured simultaneously in the liquid ejection head manufactured under the above-described conditions by setting the roller speed higher than that in Example 1 under the same temperature conditions.
By Si deep etching of a substrate 11 provided with an ejection energy generating element 12 as in Example, a common liquid chamber 13 and an ink supply port 16 were formed and further, an ejection orifice forming member 20 was formed. Then, in a step of laminating a third photosensitive resin layer 26 with the back surface of the substrate 11, it was laminated under the conditions of a combination of a stage surface temperature and a roller surface temperature as shown in Table 1, a roller pressure of 0.2 MPa and a roller speed of 5 mm/s. A liquid ejection head manufactured under the conditions of a roller surface temperature of 45° C. or higher or a stage surface temperature of 35° C. or lower had poor adhesiveness to the substrate or deteriorated flatness.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-029875, filed Feb. 22, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-029875 | Feb 2018 | JP | national |
