JP4312914B2 - Resin composition coating method and coating apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for applying a resin composition to a substrate surface in the technical field of mounting electronic components on a substrate.
[0002]
[Prior art]
The mainstream of circuit mounting technology is mixed surface mounting. In the mixed surface mounting, for example, an adhesive made of a resin composition is applied to the substrate surface, various chip components are mounted thereon, and the adhesive is cured to fix the chip components in order to prevent dropping or slipping. And it is the technique which inverts a board | substrate, inserts the lead component corresponding to the said chip component, contacts a molten solder, and solders a chip component and a lead component collectively.
[0003]
On the other hand, in recent years, a conductive paste in which a conductive filler is blended in a resin composition has attracted attention as a conductive bonding material that replaces solder, from the viewpoints of global environment and energy saving. And the practical use of the method of supplying to the electrode on a board | substrate with the application | coating method similar to the said adhesive agent is advanced.
[0004]
As a mainstream of the application method of the resin composition, there is a dispensing method in which the resin composition is discharged from a nozzle and applied onto the substrate surface in the form of dots. Therefore, an outline of the dispensing method including the conventional steps (1) to (3) will be described with reference to FIG. In step (1), the resin composition 5 filled in the syringe 6 is discharged from the tip of the nozzle 1. Next, the nozzle 1 is lowered to approach the surface of the substrate 4. The syringe 6 is provided with a member (stopper member) 2 that functions as a spacer for providing a distance between the nozzle tip and the substrate surface, and as shown in the step (2), between the nozzle tip and the substrate surface. The resin composition 5 is applied in a state where a gap is formed. In step (2), the nozzle 1 is stopped for a while while the stopper member 2 is in contact with the substrate surface. Then, when the nozzle 1 is raised and moved away from the substrate surface in the step (3), the application is completed. Thereafter, the nozzle 1 moves to another application position.
[0005]
As a method for discharging the resin composition from the tip of the nozzle, an air pulse method in which air pressure is applied to the syringe 6 filled with the resin composition and discharged is the mainstream. In addition, there is a screw type (screw type) in which a screw having a groove serving as a transport passage for the resin composition is installed inside the syringe, and the resin composition is sent from the nozzle by rotation of the screw.
[0006]
[Problems to be solved by the invention]
In recent years, with the reduction in size and weight of electronic devices, there has been a demand for higher density surface mounting, higher accuracy, and faster mounting processes. However, in the conventional method for applying a resin composition, the nozzle tip is soiled with the resin composition due to repeated application, causing a defective application shape. In addition, when the conventional coating process is speeded up, the resin composition is stringed, scattered, etc. in the process (3), which also causes a defective coating shape. And it becomes a cause which generate | occur | produces a non-solder defect (state where it is not apply | coated to the location which should apply | coat a solder) etc. in a later process.
An object of this invention is to provide the coating method and coating device of the resin composition which reduced these problems.
[0007]
[Means for Solving the Problems]
The present invention relates to a resin using a coating apparatus including a nozzle that discharges a resin composition and a mask that is provided in front of the nozzle tip and spaced apart from the nozzle tip and that has an opening that guides the resin composition discharged from the nozzle. A method of applying a composition to a substrate surface, wherein the resin composition discharged from the nozzle is applied to the substrate surface through the opening by bringing the mask into contact with the substrate surface. Regarding the method.
[0008]
In the method, it is preferable that the resin composition is discharged from the nozzle immediately after the mask contacts the substrate surface.
Further, in the above method, after applying the resin composition on the substrate surface, it is kept away the nozzle from the substrate surface while rotating the mask.
Moreover, in the said method, it is preferable that the opening diameter of the said mask corresponds to the application diameter of the resin composition when apply | coated to the substrate surface.
[0009]
Moreover, in the said method, it is preferable that the thickness of the said mask corresponds to the thickness of the resin composition when apply | coated to the substrate surface.
Moreover, in the said method, it is preferable that ratio with respect to the thickness of the opening diameter of the said mask is 1-2.
[0010]
Further, the present invention is a nozzle for discharging a resin composition, and forward is provided at a nozzle tip and spacing thereof, an opening for guiding the resin composition discharged from the nozzle in contact with the substrate surface on the substrate The present invention relates to a coating apparatus for a resin composition comprising a mask having the following.
[0011]
In the apparatus, that provided for rotation parallel to the mask substrate surface a center of the opening as the axis.
Moreover, in the said apparatus, it is preferable that ratio with respect to the thickness of the opening diameter of the said mask is 1-2.
Further, the apparatus, Ru der those discharging the resin composition from the nozzle immediately after the mask is in contact with the substrate surface.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 schematically shows an example of a process for applying the resin composition of the present invention. In FIG. 1, only the principal part of an example of the coating apparatus which can be used for the said method is shown by the cross section. Hereinafter, a description will be given with reference to FIG.
[0013]
FIG. 1 (1) shows a state in which the mask 3 of the resin composition coating apparatus of the present invention is brought close to the surface of the substrate 4. The syringe 6 is attached to a movable arm of a coating apparatus main body (not shown), and is perpendicular to the x-axis and y-axis in the plane parallel to the top surface of the base on which the substrate 4 on which the resin composition 5 is applied is set and the above-described plane. It can move in the z-axis direction. A mask 3 is attached to the syringe 6 by a stopper member 2 in parallel with the substrate 4 so as to be positioned in front of the nozzle 1 for discharging the resin composition 5. The mask 3 is provided with an opening for guiding the resin composition 5 ejected from the nozzle 1 so that the center thereof is aligned with the center of the hole at the tip of the nozzle. As shown in FIG. 1 (2), the stopper member 2 cooperates with the mask 3 when the mask 3 comes into contact with the surface of the substrate 4, and forms a constant gap between the nozzle tip and the surface of the substrate 4. It also has a function to generate. When the resin composition 5 is discharged from the nozzle 1 in this state, an appropriate amount of the resin composition can be applied only to the application portion. In addition, although the stopper member 2, the mask 3, and the syringe 6 are integrated in FIG. 1, each may be another component.
[0014]
The stopper member 2 may be, for example, a plurality of rod-shaped members provided substantially parallel to the nozzle 1 or a tubular member surrounding the nozzle 1. However, in the case of a tubular shape, the space surrounded by the stopper member 2, the mask 3, the substrate 4, and the tip of the syringe 6 and the outside so that the resin composition can be discharged while the mask 3 is in contact with the surface of the substrate 4. There must be a passage for air to communicate.
[0015]
The mask 3 has a function of preventing a defective application shape of the resin composition mainly due to dirt on the nozzle tip. When the resin composition is applied, the mask 3 comes into contact with the substrate surface and surrounds the portion to be coated. Therefore, even if the resin composition adheres to the periphery of the nozzle tip, the resin composition does not reach the lower end or the outer periphery of the mask 3. This is because it is difficult to adhere and the resin composition can be prevented from adhering to places other than the coated part.
[0016]
Although the thickness of the mask 3 varies depending on the intended application shape, it cannot be generally stated, but is preferably 0.3 to 0.5 mm. If the mask becomes too thin, the coating amount of the composition will be insufficient and the adhesive strength of the parts will be weakened. If it is too thick, it will cause stringing and scattering of the composition due to excessive coating amount. It is preferable that the thickness of the mask 3 corresponds to the thickness (application height) of the resin composition when applied to the substrate surface. This is because the coating height of the resin composition is determined by the thickness of the mask 3, so that variations in the coating height can be reduced.
[0017]
The shape of the opening 7 of the mask 3 may be generally circular from the viewpoint of versatility. Although the shape of the entire mask 3 cannot be generally described, for example, an annular shape can be mentioned.
When the opening 7 of the mask 3 is circular, the opening diameter preferably corresponds to the application diameter of the resin composition when applied to the substrate surface. This is because the coating diameter of the resin composition is determined by the opening diameter of the mask 3, so that variations in the coating diameter can be reduced. Usually, the opening diameter is preferably 0.6 to 1 mm.
[0018]
The ratio of the opening diameter of the mask 3 to the thickness is desirably 1 to 2. This is because it is easy to obtain a coating shape that can stably hold a component to be mounted in a later process on the substrate.
[0019]
The resin composition 5 is preferably discharged from the nozzle tip immediately after the mask 3 contacts the substrate surface. If the resin composition 5 is ejected before the mask 3 comes into contact with the substrate surface, the resin composition may be scattered in a portion other than the portion to be coated or the resin composition may adhere to the lower end portion of the mask 3. is there. Therefore, it is preferable that the apparatus discharges the resin composition 5 from the nozzle tip immediately after the mask 3 contacts the substrate surface. Specifically, for example, a control device similar to that used in the conventional air pulse type or screw type application process is set so that the resin composition is discharged at the moment when the mask 3 contacts the substrate surface. Can be used. In the case of the air pulse type, the pressure may be applied to the syringe 6 so that the resin composition 5 is immediately discharged from the nozzle 1 when it is detected that the mask 3 is in contact with the substrate 4.
[0020]
After the resin composition is discharged from the tip of the nozzle, the mask 3 is kept stationary for 0.01 to 0.03 seconds in a state where the mask 3 is in contact with the substrate surface so that the resin composition adheres sufficiently to the coated portion of the substrate surface. It is preferable.
[0021]
In the present invention, as the resin composition when away nozzle 1 from the substrate surface not to catch the yarn, Ru mask 3 while away the nozzle 1 from the substrate 4 by rotating the center of the opening 7 as the axis. In addition, it is preferable that the rotation is started at the same time as the mask 3 is separated from the substrate surface as much as possible in that the resin composition can be cut off crisply. In FIG. 1, since the mask 3 is integrated with the stopper member 2 and the syringe 6, the entire mask may be rotated. However, when each is a separate part, only the mask 3 may be rotated.
[0022]
The rotation speed is preferably 100 to 200 rpm. If the rotational speed is too high, the coating shape is disturbed due to vibration, and if it is too slow, the resin composition becomes crisp.
[0023]
The coating method and coating apparatus of the resin composition of the present invention are used when a liquid resin composition is coated. More specifically, it is suitable for application of a liquid resin composition comprising a liquid resin, a curing agent and a filler. In particular, the viscosity when measured at 25 ° C. using an R-type viscometer under the condition of a rotational speed of 0.5 rpm is 200 to 400 Pa · s, and when measured under the condition of a rotational speed of 5.0 rpm, the viscosity is 25. It is suitable for a resin composition having a viscosity of ˜65 Pa · s. This is because such a resin composition having a high thixotropy (thixotropic property) tends to cause stringing in many cases.
[0024]
【Example】
Next, the present invention will be described more specifically based on examples.
Example 1
A predetermined liquid resin composition was applied to the substrate surface using an air pulse coating method.
As the liquid resin composition, a liquid resin (bisphenol F-based epoxy resin), a curing agent (2-methylimidazole), and a filler (flaky talc) mixed at a weight ratio of 6: 1: 3 was used. . The viscosity of this resin composition at 25 ° C. was 252 Pa · s.
[0025]
First, the resin composition was filled in a syringe having a volume of 30 ml, and a coating apparatus was set up with a certain interval between the substrate and the mask as shown in FIG. The syringe has a nozzle and a tubular stopper having an inner diameter of 1.5 mm, a wall thickness of 0.7 mm, and a hole communicating with the inner wall surface and the outer wall surface (a hole for allowing air to pass through when discharging the resin composition) The member and the annular mask are integrally formed. The length of the nozzle protruding from the end of the syringe and the length of the tubular stopper member are 2 mm and 3 mm, respectively, and the thickness of the mask is 0.3 mm. The outer diameter of the mask is 2.9 mm, which is the same as the outer diameter of the tubular support member, and the opening diameter of the mask is 0.6 mm.
[0026]
The air pulse of the coating apparatus was set so that the resin composition was discharged immediately after the mask contacted the surface of the substrate as shown in (2) of FIG. The amount of the resin composition discharged at one time is set to 3 × 10 ⁻⁴ ml.
The mask integrated with the syringe, the nozzle, and the stopper member can rotate about the center of the opening. Then, 0.02 seconds after the mask comes into contact with the substrate surface, it is set to rotate at a rotational speed of 160 rpm simultaneously with the rise of the nozzle as shown in FIG. After rising, the nozzle is set to move to the next position and repeat application.
[0027]
When the coating shape of the resin composition was observed by repeating the coating 400 times, the coating shape was uniform, and no scattering of the resin composition or the like was observed in any portion other than the coated portion on the substrate surface. The shape of the applied resin composition is a circle having the same diameter as the opening diameter of the mask, and the height of the highest part from the substrate of the applied resin composition is substantially the same as the thickness of the mask. there were.
In the embodiment, bisphenol F-based epoxy resin is used as the liquid resin, but any liquid resin such as other epoxy resin, acrylic resin, or silicon resin may be used.
In the examples, 2-methylimidazole is used as the curing agent, but any other curing agent such as an amine curing agent, aromatic curing agent, amide curing agent, polymercaptan curing agent, etc. But there is no problem.
In the examples, scaly talc is used as the filler, but any other filler such as amorphous silica, spherical silica, fine powder silica, mica, barite, and titanium oxide can be used.
In the examples, the weight ratio of liquid resin: curing agent: filler was set to 6: 1: 3. However, any ratio can be used as long as the resin composition having a viscosity property capable of being applied by dispensing can be obtained. There is no problem with the ratio.
[0028]
【The invention's effect】
According to the present invention, it is possible to reduce the occurrence of coating shape defects due to contamination of the nozzle tip in the resin composition coating process, stringing of the resin composition, splashing, etc., and to reduce unsolder defects in the subsequent processes. Can do.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view schematically showing a step of an example of a resin composition coating method of the present invention in a cross section of a main part of an example of a resin composition coating apparatus of the present invention.
FIG. 2 is an explanatory view schematically showing a process of an example of a conventional resin composition coating method in a cross section of a main part of an example of a conventional resin composition coating apparatus.
[Explanation of symbols]
1 Nozzle 2 Stopper Member 3 Mask 4 Substrate 5 Resin Composition 6 Syringe 7 Opening

Claims (6)

A resin composition is formed on a substrate by using a coating apparatus having a nozzle for discharging the resin composition and a mask provided in front of the nozzle tip and spaced apart from the nozzle tip and having an opening for guiding the resin composition discharged from the nozzle. A method of applying to a surface,
The resin composition discharged from the nozzle in contact with the substrate surface is applied to the substrate surface through the opening ,
A method for applying a resin composition, comprising: applying a resin composition to a substrate surface; and moving the nozzle away from the substrate surface while rotating the mask .   The resin composition coating method according to claim 1, wherein the resin composition is discharged from the nozzle immediately after the mask contacts the substrate surface. The method for applying a resin composition according to claim 1 or 2, wherein the thickness of the mask corresponds to the thickness of the resin composition when applied to the substrate surface. The method of coating the resin composition according to any one of claims 1 to 3 ratio with respect to the thickness of the opening diameter of the mask is 1-2. A nozzle that discharges the resin composition, and a mask that is provided in front of the nozzle tip and spaced from the nozzle tip and that has an opening that contacts the substrate surface and guides the resin composition discharged from the nozzle onto the substrate. An application apparatus for a resin composition , wherein the mask is provided so as to rotate in parallel with the substrate surface about the center of the opening . 6. The resin composition coating apparatus according to claim 5 , wherein the ratio of the opening diameter of the mask to the thickness is 1-2.

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