JP2023134078A - Coating film forming method and ink jet coating device - Google Patents

Abstract

To provide a coating film forming method and ink jet coating device which can suppress coating unevenness even when a defective nozzle exists.SOLUTION: A coating film forming method for forming a coating film by discharging liquid droplets on a film forming region on a base material by an ink jet method is structured so as to perform a defective nozzle detection process for detecting a defective nozzle out of a plurality of nozzles for discharging the liquid droplets, a pre-film forming process for forming a film by discharging the liquid droplets from a normal nozzle in advance on a missing film forming region which is a film forming region to be formed by the defective nozzle detected in the defective nozzle detection process, and a main coating process of forming a film on a region except for a landing position on which the liquid droplet is to be discharged by the defective nozzle in this order.SELECTED DRAWING: Figure 2

Description

The present invention relates to a coating film forming method and an inkjet coating apparatus that form a coating film by discharging droplets onto a base material, and particularly relates to a coating film forming method and inkjet coating apparatus that can suppress coating unevenness. be.

It is desired to eject droplets onto a substrate such as glass or film by an inkjet method to form coating films (also referred to as film patterns) in various shapes such as line segments and rectangular shapes. For example, it is being considered to form thin film patterns (thin films) by using inkjet equipment for wiring patterns on wiring boards (base materials) such as printed circuit boards and package boards, and insulating film patterns for power semiconductors. .

This inkjet coating is performed using an inkjet coating apparatus as shown in FIG. 9(a). That is, the inkjet coating apparatus is equipped with a stage 100 on which a base material W is placed, and a coating unit 101 having a plurality of nozzles 104 (see FIG. 10) that discharge droplets of coating material. The coating film C is formed by ejecting droplets while the unit 101 moves with respect to the base material W on the stage 100 (FIG. 9(b)).

Specifically, the coating unit 101 has a gantry section 101a that moves in the main scanning direction (X-axis direction in the figure) relative to the base material W, and a plurality of nozzles 104 are installed in this gantry section 101a. A head unit 102 is provided. This head unit 102 is formed by arranging head modules 103 having a plurality of nozzles 104, as shown in FIG. 10(a). In this head module 103, nozzles 104 are arranged at an array pitch t in a sub-scanning direction (Y-axis direction) orthogonal to the main-scanning direction (X-axis direction). That is, when viewed from the X-axis direction, the nozzles 104 are arranged at equal intervals in the Y-axis direction (FIG. 10(b)).

The landing positions at which ink should be ejected are set in advance for all the nozzles 104, and droplets are ejected when each nozzle 104 is located at the set landing position. Specifically, for example, when forming a planar film pattern, the landing positions are set in a grid pattern on the base material W, and each nozzle 104 is located at the X-axis position of the landing position. When a droplet is ejected, a linear film extending in the Y-axis direction is formed at the X-axis position. Then, by moving the gantry part 101a once in the X-axis direction relative to the base material W and ejecting droplets to a predetermined landing position, a linear film is continuously formed in the X-axis direction. As a result, a uniform and flat coating film C is formed on the base material W (FIG. 11(a)).

Here, if a defective nozzle 104b (see FIG. 12; including non-ejection and ejection failure) exists in the head unit 102, there will be a shortage of coating material at the position where the defective nozzle 104b exists, as shown in FIG. 11(b). Therefore, an area (uncoated area f) where material is insufficient is formed in the main scanning direction between the film C' forming the coating film C. If this uncoated area f is formed, it becomes a cause of streak-like unevenness, resulting in a problem of uneven coating in which the thickness dimension standard of the coated film cannot be partially satisfied. Therefore, when a defective nozzle 104b occurs, the head unit 102 is scanned again to the uncoated area f formed by the defective nozzle 104b, and droplets are replenished from the normal nozzle 104a in the head unit 102. Recovery coating is performed to fill in the uncoated area f, and a uniform coating film C is formed as a whole.

Japanese Patent Application Publication No. 2008-111994

However, in the conventional method of performing recovery coating on the uncoated area f using the normal nozzle 104a, there was a problem that the uncoated area f could not be completely eliminated. That is, as shown in FIG. 12(b), when replenishment is performed by discharging droplets to the uncoated region f, the droplets discharged for replenishment cover the surrounding film C' forming the uncoated region f. is absorbed by surface tension. Therefore, after the uncoated area f is formed, the droplets 105 ejected for recovery coating cannot fill the depression in the uncoated area f, and the uncoated area f cannot be flattened. was there.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a coating film forming method and an inkjet coating device that can suppress the formation of uneven coating even when a defective nozzle occurs. It is said that

In order to solve the above problems, a coating film forming method and an inkjet coating apparatus of the present invention are a coating film forming method in which a coating film is formed by discharging droplets onto a film forming area on a base material by an inkjet method, the method comprising: A defective nozzle detection step detects a defective nozzle among a plurality of nozzles that eject droplets, and a defective film formation region which is a film formation region to be formed by the defective nozzle detected in the defective nozzle detection step is preliminarily applied. A pre-film forming step in which a film is formed by ejecting droplets with a normal nozzle, and a main coating step in which a film is formed in an area other than the landing position where the defective nozzle should eject, are performed in this order. There is.

According to the above-mentioned coating film forming method and inkjet coating apparatus, in the pre-film forming step, a film (pre-film) is formed in advance in the missing film forming area, which is the film forming area that should originally be formed by the defective nozzle, and then By performing the main coating step, it is possible to suppress the formation of depressions in the region where the film is missing. In other words, by forming a pre-film in advance, a film is already formed in the region where the film is missing, and in addition, the pre-film forms a film around the region where the film is missing in the next main coating process. Because it is thought to play a role in connecting the layers, it is less likely that depressions will be formed in the missing film area, and uneven coating will be avoided, compared to the conventional method of adding droplets after the uncoated area is formed. can be prevented from forming.

Further, the defective film forming region may be formed at a landing position where the defective nozzle should eject.

According to this configuration, since the missing film forming region is set as the landing position, the pre-film can be reliably formed in the uncoated region previously formed by the defective nozzle in the pre-film forming step.

Further, the defective film forming region may be formed in a predetermined region centered on the landing position where the defective nozzle should eject.

According to this configuration, since the pre-film is formed in an area having a certain width from the landing position, it is possible to reliably connect the films formed around the missing-film formation area.

According to the coating film forming method and inkjet coating apparatus of the present invention, it is possible to suppress the formation of coating unevenness even when a defective nozzle occurs.

1 is a side view schematically showing an inkjet coating device of the present invention. FIG. 3 is a top view of the inkjet coating device. FIG. 2 is a diagram showing an inkjet head section, (a) is a diagram showing the arrangement of head modules, and (b) is a diagram showing nozzle arrangement. FIG. 4 is a diagram hypothetically showing a defective film forming region, (a) is a diagram showing a case where the defective film forming region is linear, and (b) is a diagram showing a case where the defective film forming region is circular. be. FIG. 2 is a diagram for explaining the situation in which a coating film is formed, in which (a) shows a state in which a pre-film formation process has been performed, and (b) shows a state in which a main coating process has been performed after forming a pre-film. FIG. It is a flowchart which shows the coating operation of the above-mentioned inkjet coating device. It is a figure which shows the state in which the pre-film|membrane was formed on the base material, (a) is a figure seen from above, (b) is a figure seen from the X-axis direction. It is a figure showing the state in which the coating film is formed, (a) is a view of the entire base material viewed from above, (b) is a figure showing the state in which the pre-film and the films formed on both sides of it fit together, (c) is a diagram showing a state in which a coating film is integrally formed from the state in (b). It is a figure which shows schematically the conventional inkjet coating device, (a) is a side view, (b) is a top view. FIG. 2 is a diagram showing an inkjet head section, (a) is a diagram showing the arrangement of head modules, and (b) is a diagram showing nozzle arrangement. It is a figure which shows the state in which the coating film including the coating film in which the uncoated area was formed is formed, (a) is the figure seen from the whole base material from above, (b) is the figure seen from the X-axis direction. be. FIG. 4 is a diagram for explaining the state in which a coating film is formed, (a) is a diagram showing a state in which an uncoated area is formed due to a defective nozzle, and (b) is a diagram showing a state in which recovery coating is performed. It is a diagram.

Embodiments of the coating film forming method and inkjet coating apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing one embodiment of an inkjet coating device, and FIG. 2 is a top view of the inkjet coating device.

As shown in FIGS. 1 and 2, the inkjet coating apparatus includes a stage 10 on which a base material W is placed, and a droplet unit 2 that applies droplets D (coating material) to the base material W. A coating film C is formed on the substrate W by discharging droplets D (also referred to as coating liquid) while the droplet unit 2 moves on the substrate W placed on the stage 10.

In the following explanation, the direction in which this droplet unit 2 moves is referred to as the X-axis direction (main scanning direction), and the direction perpendicular to this on the horizontal plane is referred to as the Y-axis direction (sub-scanning direction or width direction). In the following description, a direction perpendicular to both the axis and the Y-axis direction will be referred to as the Z-axis direction.

The inkjet coating apparatus has a base 1, on which a stage 10 and a droplet unit 2 are provided. Specifically, a stage 10 is provided on a base 1, and a droplet unit 2 is provided so as to straddle this stage 10 in the Y-axis direction.

The stage 10 is used to place the base material W, and is configured to allow the placed base material W to be placed while maintaining a horizontal posture. Specifically, the surface of the stage 10 is formed flat, and a plurality of suction holes are formed on the surface. A vacuum pump is connected to this suction hole, and by operating the vacuum pump with the base material W placed on the surface of the stage 10, suction force is generated in the suction hole, and the base material W is leveled. It can be held by suction on the surface of the stage 10 in any posture.

The droplet unit 2 is used to apply droplets D as a coating material onto the base material W, and includes an inkjet head section 21 that discharges the coating material and a gantry that supports the inkjet head section 21. 22.

The gantry section 22 is formed into a substantially gate-shaped shape having leg sections 22a disposed on both outer sides of the stage 10 in the Y-axis direction, and a beam member 22b connecting these leg sections 22a and extending in the Y-axis direction. There is. The inkjet head section 21 is attached to this beam member 22b, and the gantry section 22 is attached so as to be movable in the X-axis direction while straddling the stage 10 in the Y-axis direction. In this embodiment, rails (not shown) extending in the X-axis direction are installed at both ends of the base 1 in the Y-axis direction, and the leg portions 22a are slidably attached to the rails. A linear motor is attached to the leg portion 22a, and by driving and controlling this linear motor, the gantry portion 22 can be moved in the X-axis direction and stopped at any position.

Further, the linear motor is provided with an encoder, and the position of the inkjet head section 21 in the X-axis direction can be determined by periodic drive pulse signals from the encoder. That is, the encoder and a control device (controller) described later are connected, and the position of the inkjet head section 21 on the X-axis is detected by the control device that receives a drive pulse signal from the encoder. .

Moreover, the beam member 22b is a columnar member that connects both legs 22a. The inkjet head section 21 is attached to this beam member 22b. Specifically, the inkjet head section 21 is attached to one side surface of the beam member 22b in the X-axis direction, and the nozzle 40 (see FIG. 3) provided on this inkjet head section 21 is attached to the surface of the stage 10. It is installed in a facing position. Therefore, as the gantry section 22 moves or stops in the X-axis direction, the inkjet head section 21 can also move or stop in the X-axis direction accordingly, and by adjusting the amount of movement of the gantry section 22. The inkjet head section 21 is positioned on the base material W placed on the surface of the stage 10, so that droplets D of coating material can be ejected onto the base material W.

Further, the inkjet head section 21 is a unit in which a plurality of nozzles 40 are integrated. In this embodiment, the inkjet head section 21 has a plurality of nozzles 40, and can eject droplets D from each nozzle 40.

The inkjet head section 21 includes a plurality of head modules 31 each having a nozzle 40, as shown in FIG. 3(a). In this embodiment, a plurality of head modules 31 are arranged along the Y-axis direction (sub-scanning direction), and are arranged in a direction perpendicular to the coating direction. Further, the head module 31 has a plurality of nozzles 40, and the nozzles 40 are arranged in one direction at a predetermined arrangement pitch t (FIG. 3(b)).

Further, the head modules 31 are arranged in a staggered manner so that each has an overlapping portion. In the example of FIG. 3A, adjacent head modules 31 are arranged so as to be alternately shifted in the X-axis direction. That is, since the dimensions of these head modules 31 are different between the arrangement interval of the nozzles 40 and both end portions of the head module 31, they are shifted in the X-axis direction while being shifted in the Y-axis direction so as to offset the dimensions of both end portions. Arranged in That is, in the inkjet head section 21, the normal nozzles 40 are arranged at equal intervals in the Y-axis direction when viewed in the X-axis direction, and all the normal nozzles 40 are arranged in the Y-axis direction as a whole. They are arranged at a constant pitch along the axial direction, and are arranged at equal intervals in the Y-axis direction when viewed from the X-axis direction. Thereby, as shown in FIG. 2, by moving the gantry section 22 in the X-axis direction, the droplet D can be made to land on the entire film formation area S on the base material W in one scan.

Further, the inkjet coating device has a control device. The control device controls the drive of the various units described above, and controls the drive device of each unit to execute a series of coating operations according to a pre-stored program, and also performs various calculations necessary for the coating operation. This is what we do. In this embodiment, a coating program for forming a flat and uniform coating film C is stored in the control device. The control device is equipped with processing modes necessary to form the coating film C, and in this embodiment, a defective nozzle detection mode, a pre-film formation mode, and a main coating mode are stored. That is, by executing these modes, even if a defective nozzle 40b (see FIG. 5(b)) occurs, coating unevenness caused by the defective nozzle 40b can be suppressed and a flat coating film C can be formed. be able to.

The defective nozzle detection mode is a mode for checking whether or not there is a defective nozzle 40b (including non-ejection and ejection failure) in each nozzle 40 of the inkjet head section 21. Specifically, before forming the coating film C, the discharge state is inspected, and, for example, droplets D are landed from all the nozzles 40 on a test pattern film (not shown), and image information of the landed droplets D is determined. The shape and position are confirmed, and the presence or absence of a defective nozzle 40b is determined.

Here, when the defective nozzle 40b is detected in the defective nozzle detection mode, the droplet D is not ejected to the landing position P where it would normally be ejected if the defective nozzle 40b were normal, so the area where the film is chipped (A region where the coating liquid is insufficient), that is, an uncoated region occurs. Therefore, in the mapping data that is the landing position data for forming the coating film C, the substitute nozzle 40c, which ejects droplets D instead of the faulty nozzle 40b, is moved from the normal nozzle 40a to the landing position P where the faulty nozzle 40b should eject. Selected. The substitute nozzle 40c may be one or more substitute nozzles 40c for one defective nozzle 40b, and the substitute nozzle 40c is selected so that the coating film C can be formed efficiently from the viewpoint of takt time.

Here, the missing film formation region R is a set region in which a film (pre-film E) is formed in advance in order to suppress the occurrence of uncoated regions. This defective film formation region R may be set at the landing position P when the defective nozzle 40b is a normal nozzle 40a, but in this embodiment, it is set to a predetermined width centered on the landing position P of the defective nozzle 40b. It is set as an area with . Here, FIG. 4 is a diagram hypothetically showing the defective film formation region R, and the shaded area shows the film C' formed by the normal nozzle 40a after the formation of the pre-film E, and these films C' A missing film formation region R is formed between the two. Further, the circle in FIG. 4(a) indicates the landing position P. In this embodiment, as shown in FIG. 4A, the defective film forming region R is centered on the landing position P (solid circle) of the original defective nozzle 40b, and the landing position P of one nozzle is located on both sides of the landing position P (solid circle). ' (dashed circle) is set as the area that includes. Thereby, the films C' on both sides formed by the normal nozzle 40a can easily fit together, and the films can be reliably connected to each other. In this embodiment, in FIG. 4A, the droplet D is ejected to the landing position P indicated by a solid line using the substitute nozzle 40c for the defective nozzle 40b, but the droplet D is ejected to the landing position P indicated by a broken line in FIG. may use the substitute nozzle 40c, but due to takt time, normal nozzles 40a (referred to as selected nozzles 40d) other than the substitute nozzle 40c, for example, normal nozzles 40a located on both sides of the substitute nozzle 40c, are separately selected as selected nozzles. 40d.

The pre-film formation mode is a mode for forming a film (pre-film E) in the missing film formation region R in advance before forming the coating film C. That is, the selected substitute nozzle 40c ejects droplets D to the landing position P where the defective nozzle 40b should eject, thereby forming the pre-film E. In this embodiment, since the missing film formation region R is set to a predetermined region, the droplet D is ejected to the missing film forming region R by the substitute nozzle 40c and the selection nozzle 40d, and a pre-film E is formed (Fig. 5(a)).

This application mode is a mode in which a film is formed in an area other than the landing position P where the defective nozzle 40b should eject. Specifically, droplets D are ejected from the normal nozzles 40a other than the defective nozzle 40b to the respective landing positions P according to the mapping data. That is, a film is formed by ejecting droplets D from the nozzle 40 at the landing position P (not shown) in the shaded area in FIG. 4(a). Normally, the droplets D are also ejected to the landing position P' next to the landing position P of the defective nozzle 40b, so that the droplets D become familiar with each other and a film C' is formed (see the diagonal lines in FIG. 4(a). The membranes of the regions) are connected to each other via the pre-membrane E (FIG. 5(b)). As a result, a flat coating film C is formed on the base material W.

Next, the coating film forming method of the inkjet coating apparatus of this embodiment will be explained based on the flowchart of FIG. 6.

First, in step S1, a defective nozzle detection step is performed. Specifically, droplets D are ejected from all the nozzles 40 of the inkjet head section 21 onto a test pattern film (not shown), and the presence or absence of a defective nozzle 40b is determined from the image information of the ejected droplets D. If a defective nozzle 40b is detected, a substitute nozzle 40c is selected to eject droplets D to the landing position P of the defective nozzle 40b.

Next, in step S2, a base material carrying-in process is performed. Specifically, when the base material W is supplied onto the stage 10, the base material W is positioned at a predetermined position and fixed onto the stage 10 by suction. Then, based on the imported base material W data, mapping data of the base material W is calculated. The mapping data of the pre-film E formed in the defective film formation region R and the mapping data of the film formed in areas other than the defective film formation region R are calculated, and the landing of the pre-film formation mode and the main coating mode is performed. The position P and the nozzle 40 to be ejected to the landing position P are selected.

Next, in step S3, a coating process is performed. That is, the coating film C is formed on the base material W by sequentially executing steps S31 and S32.

First, in step S31, a pre-film forming process is performed. Specifically, based on the mapping data, droplets D are ejected from the substitute nozzle 40c and the selected nozzle 40d while the inkjet head section 21 is running, thereby forming the pre-film E in the film-missing formation region R of the base material W. is formed (FIG. 5(a)). In this embodiment, in the coating film C forming region, a pre-film E having a shape extending in the X-axis direction is formed as shown in FIG. 7(a).

Next, in step S32, a main coating process is performed. Specifically, based on the mapping data, droplets D are ejected using the normal nozzle 40a to form a film in a region other than the landing position P where the defective nozzle 40b should eject. That is, a film is formed by ejecting droplets D from the normal nozzle 40a at a landing position P other than the landing position P to be ejected from the defective nozzle 40b so as to be adjacent to the pre-formed pre-film E ( Figure 8(a)). In this embodiment, the droplets D are also ejected to the landing positions P located on both sides of the landing position P that should be ejected by the defective nozzle 40b, so that the pre-film E and the droplets D become more familiar with each other. The films C' formed on both sides of the missing film forming region R are easily connected to each other (FIG. 8(b)). As a result, the films C' formed on both sides of the defective film forming region R are attracted to each other and integrated, thereby suppressing the formation of a depression at the landing position P where the defective nozzle 40b should eject, and flattening the film C'. A coating film C is formed.

Next, in step S4, a base material unloading process is performed. That is, once the film pattern C is formed in the film formation area S on the base material W, the base material W is carried out from the stage 10 by a robot hand or the like.

As described above, according to the coating film forming method and inkjet coating apparatus in the above embodiment, in the pre-film forming step, the missing film forming region R, which is the film forming region S that should originally be formed by the defective nozzle 40b, is preliminarily coated. By forming the film (pre-film E) and then performing the main coating process, it is possible to suppress the formation of depressions in the film-deficit forming region R. That is, by forming the pre-film E in advance, a film has already been formed in the missing-film forming area R, and in addition, the pre-film E is coated around the missing-film forming area R in the next main coating process. Because it is thought to play a role in connecting the formed films C' to each other, it is possible to create a depression in the missing film forming region R compared to the conventional method of adding droplets D after an uncoated region is formed. This makes it difficult for the coating to form, and it is possible to suppress the formation of uneven coating.

Furthermore, in the above embodiment, the case where the coating film C is formed in one scan of the droplet unit 2 and the missing film formation region R has a linear shape extending in the X-axis direction has been described. It can also be applied to a case where the coating film C is formed by scanning multiple times in the direction and the Y-axis direction, that is, a case where the missing film forming region R is formed in a dotted manner. In this case, as shown in FIG. 4B, for example, the defective film forming region R is centered around the landing position P (solid circle) of the original defective nozzle 40b, and around the landing position P of one nozzle. ' (dashed circle) is set as the area that contains it. As a result, the droplet D (pre-film E) located at the center and the surrounding film become familiar with each other, thereby suppressing the formation of a depression in the film-defective region R.

Further, in the above embodiment, an example has been described in which the defective film forming region R is formed in a predetermined region centered on the landing position P where the defective nozzle 40b should eject. R may be the landing position P itself where the defective nozzle 40b should eject.

Furthermore, in the above embodiment, an example has been described in which the predetermined region of the defective film forming region R is set to the landing position P for one nozzle on both sides of the landing position P where the defective nozzle 40b should eject. The landing position P for three nozzles may be set, or an area that is not set as the landing position P may be set. However, if the setting area of the defective film forming area R is too wide, there is a risk that the depression cannot be suppressed, so it is necessary to adjust and set the area as appropriate so that the depression is not formed.

2 Droplet unit 10 Stage 21 Inkjet head section 22 Gantry section 40 Nozzle 40a Normal nozzle 40b Defective nozzle 40c Substitute nozzle 40d Selection nozzle C Coating film E Pre-film P, P' Landing position R Missing film formation area S Film formation area W Base material

Claims (4)

A coating film forming method in which a coating film is formed by discharging droplets onto a film forming area on a base material by an inkjet method, the method comprising:
a defective nozzle detection step of detecting a defective nozzle among the plurality of nozzles that eject droplets;
a pre-film forming step of forming a film by ejecting droplets in advance with a normal nozzle onto a film-forming region with a defective film, which is a film forming region to be formed by the faulty nozzle detected in the faulty nozzle detection step;
a main coating step of forming a film in an area other than the landing position where the defective nozzle should eject;
A coating film forming method characterized by performing the following steps in this order. 2. The coating film forming method according to claim 1, wherein the defective film forming region is formed at a landing position where the defective nozzle should eject. 3. The coating film forming method according to claim 1, wherein the defective film forming region is formed in a predetermined region centered on a landing position where the defective nozzle should eject. A stage on which the base material is placed;
a droplet unit that discharges droplets onto a film formation area on the base material to form a coating film while moving relative to the base material placed on the stage;
a control device that controls the stage and the droplet unit;
An inkjet coating device having:
The control device has a defective nozzle detection mode in which a defective nozzle is detected among a plurality of nozzles that eject droplets;
a pre-film formation mode in which film formation is performed by ejecting droplets in advance from a normal nozzle to a film-deficient film formation region that is a film formation region to be formed by the faulty nozzle detected in the faulty nozzle detection process;
a main application mode in which a film is formed in an area other than the landing position where the defective nozzle should eject;
An inkjet coating device that performs the following.

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