JP2021030471A - Method for manufacturing substrate for liquid discharge head - Google Patents

Abstract

To provide a substrate for a liquid discharge head which has high joint reliability between members using an adhesive.SOLUTION: A method for manufacturing a substrate for a liquid discharge head includes steps of: applying an adhesive to a protrusion of a first member having a recess and the protrusion; flattening the adhesive applied to the protrusion so as not to block the recess; joining a second member and the first member by interposing the flattened adhesive therebetween; and curing the adhesive.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a substrate for a liquid discharge head.

Structures obtained by microfabrication of semiconductor substrates are widely used in the field of MEMS (Micro Electro Mechanical Systems) and functional devices of electromechanical machines. As an example, there is a liquid discharge head of a liquid discharge recording type that records by landing a discharged droplet on a recording medium.

The liquid discharge head substrate is composed of a substrate made of silicon or the like, which is formed with a liquid supply port and a liquid flow path for flowing the discharge liquid. In joining substrates having such a fine structure, a method of joining substrates to each other using an adhesive is widely used.

In Patent Document 1, an adhesive is applied flatly on a film, the adhesive is transferred by pressing against a member to be joined, the adhesive is temporarily cured, and then the adhesive is joined to another member via the adhesive. The method of main curing is described.

JP 2015-166426

In the above technique, the adhesive is transferred by pressing the member to be joined, but the fluidity of the adhesive is low only by pressing, and there is a concern that the adhesive may be poorly transferred. Further, when the adhesive is transferred to the member, crying may occur inside the adhesive, and the film thickness of the transferred adhesive may be uneven. When a member to which the adhesive is transferred is joined to another member in a state where the film thickness of the adhesive is uneven, voids are generated between the joined members due to the embedding of air bubbles between the joined members due to the uneven film thickness of the adhesive. , There was a problem that ink leaked.
An object of the present invention is to solve the above-mentioned problems, that is, to provide a method capable of manufacturing a substrate for a liquid discharge head having high bonding reliability.

According to one aspect of the present invention, the step of applying the adhesive to the convex portion of the first member having the concave portion and the convex portion and the adhesive applied to the convex portion do not block the concave portion. For a liquid discharge head, which includes a step of flattening, a step of joining the second member and the first member via the flattened adhesive, and a step of curing the adhesive. A method of manufacturing a substrate is provided.

According to the present invention, it is possible to manufacture a substrate for a liquid discharge head having high joining reliability.

It is a cutaway part perspective view of the substrate for a liquid discharge head manufactured by embodiment of this invention. It is a process sectional view which shows the manufacturing method of the substrate for a liquid discharge head by embodiment (1st Embodiment) of this invention. It is a process cross-sectional view (explanatory view of the adhesive transfer process) which shows the manufacturing method of the substrate for a liquid discharge head by embodiment (1st Embodiment) of this invention. It is a process sectional view (the explanatory view of the flattening process) which shows the manufacturing method of the substrate for a liquid discharge head according to the Embodiment (1st Embodiment) of this invention. It is a process sectional view which shows the manufacturing method of the substrate for a liquid discharge head by another embodiment (second embodiment) of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
(First Embodiment)
FIG. 1 is a perspective view of a broken portion (including a portion showing a cross section) of a liquid discharge head manufactured according to an embodiment of the present invention. As shown in FIG. 1, the surface of the substrate 1 is an energy generating element 2 that generates energy for discharging a liquid such as ink, an ink supply port 4 that communicates with the front surface, and an opening on the back surface that communicates with the ink supply port 4. Wiring (not shown) connected to the common liquid chamber 3 and the energy generating element 2 is formed. The substrate 1 corresponds to a first member having a concave portion and a convex portion, and the common liquid chamber 3 can be the concave portion, and the back surface of the substrate excluding the common liquid chamber can be the convex portion.

Further, on the surface side of the substrate 1 on which the energy generating element 2 is formed, a flow path forming member 6 has a plurality of discharge ports 5 for discharging liquid and a flow path (pressure chamber) communicating with each of these discharge ports 5. Is provided. Further, on the back surface side of the substrate 1, as a second member, a lid structure 7 provided with an opening 9 for supplying a liquid such as ink to the common liquid chamber 3 is provided. In the present specification, the terms "front" and "back" refer to the surface on which the flow path forming member 6 is arranged on the substrate 1 as the "front" and the surface on which the lid structure 7 is arranged as the "back". To do.

As described above, in the first member, a concave portion is formed on the surface (back surface) of the first member (board) on the side where the second member (lid structure) is joined, and the portion other than the concave portion is defined as a convex portion. It is a member to be used. The first member has a plurality of convex portions on the surface (back surface) on the side to be joined with the second member (lid structure), and the top surface of the convex portions is a member in the same plane. Is preferable.

In the configuration shown in FIG. 1 described above, the liquid is supplied from the common liquid chamber 3 to the flow path of the flow path forming member 6 and is filled. Then, the liquid filled in the flow path of the flow path forming member 6 is discharged from the discharge port 5 by the energy generated by the energy generation element 2 in response to the recording signal. For example, when the energy generating element is an electrothermal converter, bubbles are instantaneously generated in the liquid. Then, utilizing the pressure change caused by the growth of the generated bubbles, the liquid is discharged as droplets from the discharge port 5 and recorded on a recording medium.

Hereinafter, a method for manufacturing a liquid discharge head according to an embodiment of the present invention will be described with reference to the drawings.

2 (a) to 2 (g) are process cross-sectional views showing a process flow of a method for manufacturing a liquid discharge head according to the present embodiment. 2 (a) to 2 (g) show schematic cross-sectional views in each step corresponding to the cross section along the AA'line of FIG. 1 (cross section cut in the direction perpendicular to the substrate surface). ..

First, as shown in FIG. 2A, a substrate 1 on which an energy generating element 2, a common liquid chamber 3, and an ink supply port 4 are formed is prepared. A surface membrane layer (not shown) composed of wiring, an interlayer insulating film, and the like is formed on the surface of the substrate 1.

Next, as shown in FIG. 2B, a flow path forming member 6 having a flow path (pressure chamber) from the ink supply port 4 to the discharge port 5 is formed. As an example of the method for forming the flow path forming member 6, there is a method in which the steps of laminating a film-formed photosensitive resin, exposing and developing the film are repeated a plurality of times (for example, twice).

Next, as shown in FIG. 2C, the substrate 1 is inverted and the adhesive layer 8 is transferred to the back surface of the substrate 1. Here, the details of the transfer process of the adhesive layer 8 will be described with reference to FIGS. 3 (a) to 3 (d).

First, as shown in FIG. 3A, for example, a member in which the adhesive layer 8 is formed on the support 10 (base material) is prepared.

The adhesive layer 8 used in this embodiment can be formed of a photosensitive resin. Examples of such a resin include epoxy resin, acrylic resin, urethane resin and the like. Examples of the epoxy resin include bisphenol A type, cresol novolac type, and alicyclic epoxy resin. Examples of the acrylic resin include methacrylate-based resins such as polymethylmethacrylate. Examples of the urethane resin include polyurethane and the like. Examples of the solvent for dissolving these resins include organic solvents such as PGMEA (propylene glycol methyl ether acetate), cyclohexanone, methyl ethyl ketone, and xylene. There are positive type and negative type as the photosensitive resin, and it is desirable to use the negative type resin which cures by the cross-linking reaction at the time of photosensitivity as the resin forming the adhesive layer. Further, it is preferable to form an adhesive layer using an adhesive containing such a photosensitive resin and curable by heating.

Next, as shown in FIG. 3B, in order to transfer the adhesive layer 8 to the substrate 1, the side of the support 10 on which the adhesive layer 8 is formed is placed on the back surface side (convex portion) of the substrate 1. Press.

As the support 10, for example, a film can be used. Examples of this film include resin films such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), COC (cycloolefin copolymer), and COP (cycloolefin polymer).

As the pressing device, a general laminator device having a roll-shaped pressing member, a pressing device having a flat plate-shaped pressing member, or the like can be appropriately selected and used. The pressure at the time of pressing can be set to 0.1 MPa or more and 1.0 MPa or less, preferably 0.1 MPa or more and 0.5 MPa or less.

An opening pattern of the common liquid chamber 3 is formed on the back surface of the substrate 1. Therefore, when the adhesive layer 8 is transferred, the adhesive layer 8 does not block the opening pattern (recess) of the common liquid chamber 3, and the top surface of the protrusion (convex) (the non-opening on the back surface of the substrate 1). It is preferable to transfer the adhesive layer 8 only to the adhesive layer 8.

When the adhesive layer 8 is transferred by pressing the support 10, if the fluidity of the adhesive layer 8 is low, poor adhesion between the adhesive layer 8 and the substrate 1 occurs, resulting in poor transfer of the adhesive layer 8. It may occur. Therefore, it is preferable to press while heating. Assuming that the softening temperature of the adhesive layer 8 is T0 and the heating temperature at the time of pressing the adhesive layer 8 for transfer is T1, the heating temperature T1 is preferably higher than the softening temperature T0 of the adhesive layer 8. By heating at a temperature higher than the softening temperature T0, the fluidity of the adhesive layer 8 is increased, the adhesion between the adhesive layer 8 and the substrate 1 is improved, and transfer defects due to poor adhesion can be suppressed. The heating at the time of pressing for the transfer of the adhesive layer can be performed by heating the pressing member that presses the stage 12 and / and the support 10 on which the surface side of the substrate 1 is placed to a temperature T1 or higher. .. On the other hand, if the heating temperature T1 at the time of pressing is too high, it becomes difficult to transfer the adhesive layer 8 only to the top surface of the protrusion (the non-opening on the back surface of the substrate 1), so that the adhesive layer 8 opens. It is preferable to set the temperature range so that it does not enter the opening of the pattern. It is preferably lower than the heating temperature T2 at the time of pressing in the subsequent flattening step.

Next, as shown in FIG. 3C, the support 10 (base material) is peeled off from the substrate 1 and the adhesive layer 8 is transferred to the substrate 1. When the support 10 (base material) is peeled off from the substrate 1, it is preferable that the adhesive layer is overheated. At that time, it is preferable to peel off the support 10 from the substrate 1 while the stage 12 is heated to a temperature higher than the softening temperature T0 of the adhesive layer 8. By peeling the adhesive layer 8 while maintaining high fluidity, the substrate 1 side and the support 10 side can be separated from each other, and the adhesive layer 8 can be coagulated, broken and transferred only to the target portion of the substrate 1. It will be possible. As a result, as shown in FIGS. 3 (c) and 3 (d), irregularities are formed on the surface of the adhesive layer 8 transferred to the substrate 1, resulting in uneven film thickness.
In the present embodiment, the transfer method is used as a method for applying the adhesive layer 8 to the substrate 1, but various methods such as a stamping method and a brush coating can be adopted.

By the steps described above, as shown in FIG. 2C (corresponding to FIG. 3D), the substrate 1 to which the adhesive layer 8 is applied can be obtained.

Next, as shown in FIG. 2D, the transferred adhesive layer 8 is flattened to improve the uneven film thickness of the adhesive. Here, the details of the flattening process will be described with reference to FIGS. 4A to 4E. The step of flattening the transferred adhesive layer includes a step of flattening the adhesive layer by pressing the adhesive layer via a pressing auxiliary member and a step of peeling off the pressing auxiliary member thereafter. Including.

First, as shown in FIG. 4A, a pressing auxiliary member 11 for flattening is prepared. As the pressing auxiliary member 11, for example, a film-shaped member (planar-shaped member) can be used.

Next, as shown in FIGS. 4 (b) and 4 (c), the side of the substrate 1 to which the adhesive layer 8 is applied is pressed through the pressing auxiliary member 11 to flatten the adhesive layer.

As the pressing device, a general laminator device having a roll-shaped pressing member, a pressing device having a flat plate-shaped pressing member, or the like can be appropriately selected and used. The pressure at the time of pressing can be set, for example, 0.1 MPa or more and 0.5 MPa or less, and 0.1 MPa or more and 0.3 MPa or less.

At the time of pressing for flattening, it is preferable to heat at a temperature T2 higher than the softening temperature T0 of the adhesive layer in order to increase the fluidity of the adhesive layer. The heating at the time of pressing for flattening the adhesive layer can be performed by heating the stage 12 and / and the pressing auxiliary member 11 on which the surface side of the substrate 1 is placed to a temperature T2 or higher.

Next, as shown in FIG. 4D, the flattening auxiliary member 11 is peeled off from the substrate 1. When the pressing auxiliary member 11 is peeled off, it is preferable that the substrate 1 is arranged on the cooling stage 13 and the adhesive layer is cooled to a temperature T3 lower than the softening temperature T0 of the adhesive layer 8. If the pressing auxiliary member 11 is peeled off at a temperature higher than the softening temperature T0 of the adhesive layer 8, the adhesive layer 8 may also adhere to the pressing auxiliary member 11 side, causing uneven film thickness of the adhesive layer. This is because, under such a high temperature, the fluidity of the adhesive layer 8 is high, and the adhesion between the adhesive layer 8 and the pressing auxiliary member 11 is enhanced. Therefore, it is preferable to cool the adhesive layer 8 to a temperature T3 lower than the softening temperature T0 and then peel off the pressing auxiliary member 11. As a result, it is possible to prevent the adhesive layer from adhering to the pressing auxiliary member 11 side, and it is possible to obtain the adhesive layer 8 formed flat on the substrate 1 without reducing the film thickness of the adhesive layer. It can be done (Fig. 4 (e)).

As the pressing auxiliary member 11 for flattening, a resin film such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), COC (cycloolefin copolymer), COP (cycloolefin polymer) is used. be able to. The surface of these films may be subjected to a mold release treatment. However, if the difference in linear expansion coefficient between the pressing auxiliary member 11 and the substrate 1 is large, the following problems may occur. That is, during heating and cooling during the flattening process, the adhesive layer 8 is deformed due to the difference in linear expansion coefficient between the substrate 1 and the pressing auxiliary member 11, and the adhesive layer 8 is the top surface of the protrusion on the back surface side of the substrate 1. May protrude toward the opening (recess) side. Therefore, the coefficient of linear expansion of the pressing auxiliary member is preferably close to that of the substrate 1 (first member), and the difference in linear expansion coefficient between the substrate 1 and the pressing auxiliary member is preferably 20 ppm / K or less.

In order to enhance the effect of the flattening treatment (pressing), it is desirable that the temperature T2 at the time of the flattening treatment (pressing) is larger than the temperature T1 at the time of transferring the adhesive layer. If the temperature T2 during the flattening process (pressing) is too high, it becomes difficult to maintain the adhesive layer 8 only on the top surface of the protrusion (the non-opening on the back surface of the substrate 1), so that the adhesive layer 8 It is preferable to set the temperature range so that the adhesive does not enter the opening of the opening pattern.

As described above, with respect to the softening temperature T0 of the adhesive layer, the temperature at the time of processing in each step (the temperature T1 at the time of pressing for applying the adhesive layer, the temperature T2 at the time of pressing for flattening, The temperature T3) at the time of peeling the film-like member preferably has the following relationship.
T3 <T0 <T1 <T2

As described above, as shown in FIG. 2D (corresponding to FIG. 4E), the adhesive layer 8 of the substrate 1 can be flattened.

Next, as shown in FIG. 2E, it is preferable to perform the first curing treatment (temporary curing) on the flattened adhesive layer 8 on the substrate 1.
As the first curing treatment, for example, light irradiation, heat treatment, or the like can be performed. By performing the first curing treatment before bonding, the cross-linking reaction can proceed and curing defects after bonding can be suppressed. However, if it is completely cured, it may be difficult to join the substrate 1 (first member) and the lid structure (second member) 7. Therefore, it is desirable that the first curing treatment (temporary curing) is performed so that the degree of curing of the adhesive layer 8 is 10 to 65%. When the first curing treatment (temporary curing) is performed, it is preferable that an adhesive layer is formed using a photosensitive adhesive containing a photosensitive resin as a base, and the adhesive layer is irradiated with light to be temporarily cured.

Next, as shown in FIG. 2 (f), the lid structure 7 is formed. The lid structure 7 is made of, for example, silicon or the like, and an opening is formed by etching or laser processing.

Next, as shown in FIG. 2 (g), the substrate 1 and the lid structure 7 are joined to each other via the adhesive layer 8, and then a second curing treatment (main curing) is performed. The second curing treatment is, for example, a heat treatment, which can increase the degree of curing of the adhesive layer 8 and increase the bonding strength between the substrate 1 and the lid structure 7.

Through the above steps, a substrate for a liquid discharge head according to an embodiment of the present invention is manufactured. According to the manufacturing method according to the embodiment of the present invention, it is possible to improve transfer failure of the adhesive layer and uneven film thickness of the adhesive layer. As a result, it is possible to manufacture a good substrate for a liquid discharge head having high bonding reliability and reduced voids between the bonding members.

(Second embodiment)
The second embodiment will be described below with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.

The adhesive layer 8 used in this embodiment can be formed of a photosensitive resin. As such a resin, a photosensitive resin that can be used in the above-mentioned first embodiment can be used. As the resin forming the adhesive layer 8, it is desirable to use a negative type resin in which curing proceeds by a cross-linking reaction during photosensitization. Further, it is preferable to form an adhesive layer using an adhesive containing such a photosensitive resin and curable by heating.

Similar to the first embodiment, the substrate 1 on which the flow path forming member 6 is formed is prepared (FIG. 5 (a)), and then the adhesive layer 8 is transferred to the substrate 1 (FIG. 5 (b)).

Next, the adhesive layer 8 is flattened. This flattening process can also be performed in the same manner as in the first embodiment.

In the second embodiment, before the step of joining the substrate 1 (first member) and the lid structure 7 (second member) and curing (mainly curing) the adhesive, the adhesive protrudes to the concave side. Includes the step of removing the adhesive.
Also in the second embodiment, the adhesive layer 8 can be transferred only to the top surface of the protrusion of the substrate 1, but it is slightly pressed during flattening, as shown in FIG. 5 (c). In addition, the opening pattern corresponding to the common liquid chamber 3 may protrude toward the opening (recess) side. If such protrusion occurs, the common liquid chamber 3 may be narrowed and the stability of ink ejection may be reduced. Further, when the opening pattern is fine, the common liquid chamber 3 may be blocked due to the protrusion of the adhesive layer. Therefore, it is preferable to remove the adhesive layer 8 protruding toward the opening (recess) side. According to the second embodiment, the protruding adhesive layer 8 can be easily removed. In the present embodiment, the adhesive layer is transferred to the substrate 1 (first member), pressed and flattened, and then only the portion directly above the convex portion on the joint surface side of the substrate 1 (first member) is selectively selected. Is irradiated with light to perform temporary curing. Since the adhesive layer portion protruding from the top surface of the convex portion of the substrate 1 (first member) to the concave portion side is uncured, it can be easily removed.

Next, as shown in FIG. 5D, the first curing treatment (temporary curing) is performed. The first curing treatment is carried out by light irradiation, and only the portion directly above the top surface of the protrusion of the substrate 1 of the adhesive layer is exposed using a mask. As a result, when a negative resin is used as the adhesive, only the portion of the adhesive layer directly above the top surface of the protrusion of the substrate 1 is cured.

Next, the lid structure 7 is formed as shown in FIG. 5 (e), and the substrate 1 and the lid structure 7 are joined via the adhesive layer 8 as shown in FIG. 5 (f).

Next, a developing process is performed as shown in FIG. 5 (g) to remove the uncured adhesive layer 8 protruding from the top surface of the protrusion toward the opening (recess) side. Next, a second curing treatment (main curing) is performed to increase the bonding strength of the adhesive layer.

Through the above steps, a substrate for a liquid discharge head according to an embodiment of the present invention is manufactured. According to the manufacturing method according to the embodiment of the present invention, it is possible to improve transfer failure of the adhesive layer and uneven film thickness of the adhesive layer without the adhesive layer protruding from a predetermined portion. As a result, it is possible to manufacture a good liquid discharge head having high joint reliability and reduced voids between the joint members.

Hereinafter, the method for manufacturing a substrate for a liquid discharge head according to the present invention will be specifically described with reference to the drawings with reference to examples.

(Example 1)
The first embodiment described above will be specifically described with reference to Example 1.
First, as shown in FIG. 2A, a silicon substrate 1 including an energy generating element 2, a common liquid chamber 3, and an ink supply port 4 was prepared. Next, as shown in FIG. 2B, the flow path forming member 6 was provided on the substrate 1. The ink supply port 4 and the common liquid chamber 3 were formed by a Bosch process by a RIE (reactive ion etching) method.

Next, a film on which the adhesive layer 8 was formed was produced as follows (FIG. 3 (a)). First, an adhesive made of a photosensitive resin was applied onto the support 10 (PET film) by a spin coating method so as to have a film thickness of 20 μm. Subsequently, the adhesive coating film was dried in an oven at 70 ° C. to obtain the dry film shown in FIG. 3 (a).

Next, as shown in FIG. 3B, the substrate 1 is inverted, and the adhesive layer 8 formed on the support 10 is applied to the substrate 1 at a stage temperature of 70 ° C. and a roller pressure of 0.15 MPa by a pressing device. Pressed against the back surface side (joint surface). The softening temperature of the adhesive resin used in this example is 65 ° C.

Next, as shown in FIG. 3C, the support 10 (PET film) was peeled off at a stage temperature of 70 ° C., and the adhesive layer 8 was coagulated, fractured and transferred to the substrate 1 (FIG. 3D). FIG. 2C. The thickness of the adhesive layer 8 transferred to the substrate 1 was 10 μm on average, and the unevenness on the surface was 10 μm as measured by a white interferometer.

Next, the pressing auxiliary member 11 shown in FIG. 4A was prepared. Subsequently, as shown in FIGS. 4 (b) and 4 (c), in order to improve the uneven film thickness of the adhesive layer 8, the side of the substrate 1 to which the adhesive layer 8 is applied is pressed by the auxiliary member 11. The adhesive layer 8 was flattened by pressing through the adhesive layer 8. The flattening treatment was carried out using a laminating apparatus at a roller pressure of 0.2 MPa and a roller speed of 5 mm / s. At that time, the temperature during the flattening treatment was set to a stage temperature of 75 ° C. and a roller temperature of 75 ° C. so as to be equal to or higher than the softening temperature of the adhesive layer 8. A polyimide film having a low coefficient of linear expansion was used for the pressing auxiliary member 11.

Next, as shown in FIG. 4D, the substrate 1 was placed on the cooling stage 13, the adhesive layer 8 of the substrate 1 was cooled to 40 ° C. or lower, and the pressing auxiliary member 11 was peeled off from the substrate 1. The film thickness of the adhesive layer 8 after the flattening treatment was 10 μm on average, and the unevenness on the surface was 1 μm or less as measured by a white interferometer.

As described above, as shown in FIG. 2 (d) (corresponding to FIG. 4 (e)), the adhesive layer 8 of the substrate 1 was flattened.

Next, as shown in FIG. 2 (e), the flattened adhesive layer 8 on the substrate 1 was subjected to a first curing treatment step (temporary curing). The first curing treatment was performed by light irradiation, and the entire surface of the wafer was exposed using a batch full-face exposure machine. The exposure wavelength was 365 nm and the exposure amount was 320 mJ / cm ² . By performing the first curing treatment before bonding, the cross-linking reaction can proceed and curing defects after bonding can be suppressed. The degree of curing of the adhesive layer 8 was 40% in Vickers hardness (HV). Here, the degree of curing of the adhesive layer is a percentage of the Vickers hardness after the temporary curing (before the main curing) with respect to the Vickers hardness after the main curing. Vickers hardness (HV) can be determined by a test method conforming to JIS Z 2244: 2009.

Next, as shown in FIG. 2 (f), the lid structure 7 was formed. The lid structure 7 was formed by forming a silicon substrate by a Bosch process by a RIE (reactive ion etching) method.

Next, as shown in FIG. 2 (g), the substrate 1 and the lid structure 7 were joined by applying pressure at 25 ° C. and 4 KN with a joining device via the adhesive layer 8.

Then, the adhesive layer 8 was heated at 100 ° C. for 3 hours to perform a second curing treatment (main curing) of the adhesive layer 8. As a result, the degree of curing of the adhesive layer 8 was increased, and the bonding strength between the substrate 1 and the lid structure 7 was increased.

In the substrate for the droplet ejection head produced through the above steps, transfer defects in the adhesive layer and uneven film thickness of the adhesive layer were suppressed, and bonding reliability could be improved.

(Example 2)
In this example, in the flattening step of the adhesive layer transferred to the substrate 1, a substrate for a liquid discharge head was produced in the same manner as in Example 1 except that the adhesive layer was flattened at a temperature equal to or lower than the softening temperature of the adhesive layer. ..

First, in the same manner as in Example 1, a substrate 1 provided with a flow path forming member 7 was prepared. Next, in the same manner as in Example 1, the adhesive layer 8 formed on the support 10 is pressed against the back surface side (joining surface) of the substrate 1 with a pressing device at a stage temperature of 70 ° C. and a roller pressure of 0.15 MPa. did. The film thickness of the adhesive layer 8 transferred to the substrate 1 was 10 μm on average, and the unevenness of the surface thereof was 10 μm.

Next, as shown in FIGS. 4 (b) and 4 (c), the side of the substrate 1 to which the adhesive layer 8 is applied is pushed through the pressing auxiliary member 11 in the same manner as in the first embodiment except for the temperature condition. The adhesive layer 8 was flattened. That is, the flattening treatment was carried out at a roller pressure of 0.2 MPa and a roller speed of 5 mm / s using a laminating apparatus. At that time, the temperature during the flattening treatment was lower than the softening temperature of the adhesive layer 8, and the stage temperature was 50 ° C. and the roller temperature was 50 ° C. A polyimide film having a low coefficient of linear expansion was used for the pressing auxiliary member 11.

Next, as shown in FIG. 4D, the substrate 1 was placed on the cooling stage 13, the substrate 1 was cooled to 40 ° C. or lower, and the pressing auxiliary member 11 was peeled off from the substrate 1. The film thickness of the adhesive layer 8 after the flattening treatment was 10 μm on average. When the unevenness of the surface was measured with a white interferometer, the flattening effect was lower than that of Example 1 and was 6.5 μm, although it was reduced as compared with that before flattening.

Next, in the same manner as in Example 1, the first curing treatment step (temporary curing) of the adhesive layer 8 is performed, the adhesive layer 8 is joined to the prepared lid structure 7, and then the second curing treatment (main curing) is performed. A substrate for a droplet ejection head was obtained. However, at the time of pressurizing and joining, voids were generated in a part between the joining members. The generation of voids was partially suppressed with respect to Comparative Example 1 described later.

(Comparative Example 1)
In this example, a substrate for a liquid discharge head was produced in the same manner as in Example 1 except that the step of flattening the adhesive layer transferred to the substrate 1 was not performed.

First, in the same manner as in Example 1, a substrate 1 provided with a flow path forming member 7 was prepared. Next, in the same manner as in Example 1, the adhesive layer 8 applied to the support 10 was pressed against the joint surface of the substrate 1 with a pressing device at a stage temperature of 70 ° C. and a roller pressure of 0.15 MPa. The film thickness of the adhesive layer 8 transferred to the substrate 1 was 10 μm on average, and the unevenness of the surface thereof was 10 μm.

Next, in the same manner as in Example 1, the adhesive layer 8 transferred to the substrate 1 is subjected to a first curing treatment step (temporary curing), joined to the prepared lid structure 7, and then second. The curing treatment (main curing) of the above was performed to obtain a substrate for a droplet ejection head. However, at the time of pressurizing and joining, the unevenness of the adhesive layer 8 could not be completely crushed, and voids were generated between the joining members.

In the liquid discharge head substrate manufactured without performing the flattening step as described above, voids were generated due to embracing air bubbles between the joining members due to the uneven film thickness of the adhesive. When it was used in an inkjet recording device and operated, an ink leak occurred.

(Example 3)
The second embodiment described above will be specifically described with reference to Example 3.
First, as shown in FIG. 5A, a silicon substrate 1 including an energy generating element 2, a common liquid chamber 3, and an ink supply port 4 and provided with a flow path forming member 7 was prepared. The ink supply port 4 and the common liquid chamber 3 were formed by a Bosch process by a RIE (reactive ion etching) method.

Next, a film on which the adhesive layer 8 was formed was produced as follows (FIG. 3 (a)). First, an adhesive made of a photosensitive resin was applied onto the support 10 (PET film) by a spin coating method so as to have a film thickness of 20 μm. Subsequently, the adhesive coating film was dried in an oven at 70 ° C. to obtain the dry film shown in FIG. 3 (a).

Next, as shown in FIG. 3B, the substrate 1 is inverted, and the adhesive layer 8 formed on the support 10 is applied to the substrate 1 at a stage temperature of 70 ° C. and a roller pressure of 0.15 MPa by a pressing device. Pressed against the back surface side (joint surface). The softening temperature of the adhesive resin used in this example is 65 ° C.

Next, as shown in FIG. 3C, the support 10 (PET film) was peeled off at a stage temperature of 70 ° C., and the adhesive layer 8 was coagulated, fractured and transferred to the substrate 1 (FIG. 3D). FIG. 5 (b). The film thickness of the adhesive layer 8 transferred to the substrate 1 was 10 μm on average, and the unevenness on the surface was 10 μm as measured by a white interferometer.

Next, the pressing auxiliary member 11 shown in FIG. 4A was prepared. Subsequently, as shown in FIG. 4B, in order to improve the unevenness of the film thickness of the adhesive layer 8, the side of the substrate 1 to which the adhesive layer 8 is applied is pressed through the pressing auxiliary member 11 to adhere. The agent layer 8 was flattened. The flattening treatment was carried out using a laminating apparatus at a roller pressure of 0.2 MPa and a roller speed of 5 mm / s. At that time, the temperature during the flattening treatment was set to a stage temperature of 100 ° C. and a roller temperature of 100 ° C. so as to be equal to or higher than the softening temperature of the adhesive layer 8. As the pressing auxiliary member 11, a PET film whose surface was subjected to a mold release treatment was used.

Next, the substrate 1 was placed on the cooling stage, the adhesive layer 8 on the substrate 1 was cooled to 40 ° C. or lower, and the pressing auxiliary member 11 was peeled off from the substrate 1 (FIG. 5 (c)). The film thickness of the adhesive layer 8 after the flattening treatment was 10 μm on average, and the unevenness on the surface was 1 μm or less as measured by a white interferometer.

As shown in FIG. 5 (c), the adhesive layer 8 has a maximum opening of about 30 μm, which corresponds to the common liquid chamber, due to the fact that it was pressed during flattening and the influence of the linear expansion of the PET film used as the pressing auxiliary member. The pattern protruded toward the opening (recess) side.

Next, as shown in FIG. 5D, a first curing treatment step (temporary curing) was performed on the flattened adhesive layer on the substrate 1. The first curing treatment was performed by light irradiation, and was exposed using a mask 14 so that only the portion directly above the top surface of the protrusion of the substrate 1 of the adhesive layer was cured. The exposure wavelength was 365 nm and the exposure amount was 320 mJ / cm ² .

Next, as shown in FIG. 5 (e), the lid structure 7 was formed. The lid structure 7 was formed by forming a silicon substrate by a Bosch process by a RIE (reactive ion etching) method.

Next, as shown in FIG. 5 (f), the substrate 1 and the lid structure 7 were joined by applying pressure at 25 ° C. and 4 KN with a joining device via the adhesive layer 8.

Next, as shown in FIG. 5 (g), the uncured adhesive layer protruding from the top surface of the protrusion of the substrate 1 toward the opening (recess) side was removed by a developing device. PGMEA was used as the solvent, the rotation speed was 2000 rpm, and the treatment time was 5 seconds.

Then, the adhesive layer 8 was heated at 100 ° C. for 3 hours to perform a second curing treatment (main curing) of the adhesive layer 8.

The substrate for the droplet ejection head produced through the above steps has improved bonding reliability by improving transfer defects of the adhesive layer and uneven film thickness of the adhesive layer without the adhesive layer protruding from a predetermined position. I was able to improve.

1: Substrate 2: Energy generating element 3: Common liquid chamber 4: Ink supply port 5: Discharge port 6: Flow path forming member 7: Lid structure 8: Adhesive layer 9: Opening 10: Support 11: Pressing assist Member (film-like member)
12, 13: Stage 14: Mask

Claims (13)

A step of applying an adhesive to the convex portion of the first member having a concave portion and a convex portion, and
A step of flattening the adhesive applied to the convex portion so as not to block the concave portion, and
A step of joining the second member and the first member via the flattened adhesive, and
A method for manufacturing a substrate for a liquid discharge head, which comprises a step of curing the adhesive. The first aspect of the present invention includes a step of removing the adhesive protruding to the recess side after the step of joining the first member and the second member and before the step of curing the adhesive. The method for manufacturing a substrate for a liquid discharge head according to the description. The step of flattening the adhesive includes a step of flattening the adhesive by pressing the adhesive via a pressing auxiliary member and a step of peeling off the pressing auxiliary member thereafter.
The pressing through the pressing auxiliary member is performed at a temperature (T2) higher than the softening temperature (T0) of the adhesive.
The method for manufacturing a substrate for a liquid discharge head according to claim 1 or 2, wherein the pressing auxiliary member is peeled off at a temperature (T3) lower than the softening temperature (T0) of the adhesive. The liquid according to claim 3, wherein the step of applying the adhesive is performed at a temperature (T1) higher than the softening temperature (T0) of the adhesive and lower than the temperature (T2) at the time of pressing through the pressing auxiliary member. A method for manufacturing a substrate for a discharge head. The method for manufacturing a substrate for a liquid discharge head according to claim 3 or 4, wherein the difference in linear expansion coefficient between the pressing auxiliary member and the first base material is 20 ppm / K or less. The method for manufacturing a substrate for a liquid discharge head according to any one of claims 3 to 5, wherein the pressing auxiliary member is a film-like member. Any of claims 1 to 6, comprising a step of pre-curing the adhesive after the step of flattening the adhesive and before the step of joining the first member and the second member. The method for manufacturing a substrate for a liquid discharge head according to item 1. The method for manufacturing a substrate for a liquid discharge head according to claim 7, wherein the temporary curing of the adhesive is performed so that the degree of curing of the adhesive is 10 to 65%. The method for manufacturing a substrate for a liquid discharge head according to claim 7 or 8, wherein the temporary curing of the adhesive is performed by irradiation with light. The method for manufacturing a substrate for a liquid discharge head according to any one of claims 1 to 9, wherein the adhesive is a photosensitive resin. The steps of applying the adhesive include the steps of pressing the adhesive layer of the member on which the adhesive layer is formed on the base material against the convex portion and transferring the adhesive, according to claims 1 to 10. The method for manufacturing a substrate for a liquid discharge head according to any one of the items. The first member is a substrate having an energy generating element that generates energy for discharging a liquid on the front surface, a supply port communicating with the front surface, and a common liquid chamber communicating with the supply port and opening on the back surface. The method for manufacturing a substrate for a liquid discharge head according to any one of claims 1 to 11, wherein the common liquid chamber is the concave portion and the back surface of the substrate excluding the common liquid chamber is the convex portion. The method for manufacturing a substrate for a liquid discharge head according to claim 12, wherein the second member is a lid structure provided with an opening for supplying a liquid to the common liquid chamber.

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