JP2006310693A - Adhesive coating apparatus and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive coating apparatus capable of coating uniformly and conveniently a highly viscous and heat conductive adhesive to an object to be coated when coating the adhesive in a lump. <P>SOLUTION: Silicone rubber-made heaters 43A, 43B as heating bodies are provided on a metal mask 4. In a state where temperatures of the whole of the metal mask 4 and each nozzle 41 are raised, the highly viscous and heat conductive adhesive 5 is coated on a substrate 2. Adhesion to squeegee 61 is restrained, and the adhesive 5 is smoothly coated and viscosity distribution of the adhesive 5 on the metal mask 4 is uniformized, and the adhesive is coated uniformly on the substrate 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive application device and an adhesive application method for collectively applying a heat conductive adhesive.

  2. Description of the Related Art Conventionally, a method (screen printing coating method) in which an adhesive is collectively applied to a printed circuit board using a low viscosity adhesive such as a solder paste is known. This is realized by, for example, an apparatus as shown in FIG. Specifically, a substrate 102 to be coated is disposed on a support base 101, and a metal mask 104 having a plurality of through holes 103 is disposed on the substrate 102 at a predetermined interval. . In such an apparatus, when the squeegee 106 presses the solder paste 105 against the surface of the metal mask 104, the solder paste 105 is dropped from each through-hole 103 and applied as an adhesive 107 on the substrate 102. 11A to 11D, the squeegee 106 reciprocates on the metal mask 104 as indicated by arrows X102 to X104 (or one-way operation), so that the solder paste 105 is applied to the entire substrate 102. Is to be applied.

  In this way, the solder paste 105 is collectively applied onto the substrate 102 in accordance with the pattern of each through hole 103 in the metal mask 104. Further, since the solder paste has a low viscosity (about 160 Pa · s), the application operation is smoothly performed, and the operator who uses this apparatus does not have to worry.

  However, when the adhesive 205 having a high viscosity is used in place of the solder paste 105, such a smooth application operation is not performed. Specifically, for example, as shown by arrows X202 and X203 in FIGS. 12A and 12B, when the squeegee 106 moves one way while pressing the adhesive 205, when returning to the original position, For example, as shown in FIG. 12C, the squeegee 106 rises and tries to leave the adhesive 205 once. However, in this case, unlike the case of the solder paste 105 shown in FIG. 11C, the adhesive 205 still adheres to the squeegee 106. Therefore, as indicated by an arrow X204 in FIG. 12D, when the squeegee 106 scans in the reverse direction, a phenomenon occurs in which half of the adhesive 205 protrudes outside the application region. This is also true when the squeegee 106 is reversed from left to right.

  As described above, when the high-viscosity adhesive 205 is used, the smooth application operation is not performed. Therefore, the operator constantly monitors the amount of the adhesive 205 and returns the one protruding outside the application area with a spatula or the like. It becomes necessary to do so, and the work becomes very complicated.

  Therefore, even when such a high-viscosity adhesive is used, some proposals have been made for realizing smooth application and convenient application. For example, in Patent Document 1, a heating element composed of a silicone rubber heater is embedded in or attached to a squeegee, and a heat conductive adhesive (paste) is heated by using this squeegee, whereby the viscosity of the adhesive is increased. A coating method is disclosed which lowers the thickness.

JP 2005-1118 A

  According to the coating method described in Patent Document 1, there is a possibility of realizing smooth coating. However, in this coating method, only the viscosity of the portion in contact with the squeegee of the entire adhesive is lowered, and the viscosity of the other region portion is hardly or not changed. Therefore, with the movement of the squeegee, the adhesives having different viscosities are mixed, and the viscosity distribution of the adhesives becomes non-uniform. Such non-uniformity of the viscosity distribution causes unevenness in application.

  As described above, in the conventional technique, it is difficult to apply uniformly and conveniently to the object to be applied when collectively applying a high-viscosity heat conductive adhesive.

  The present invention has been made in view of such problems, and the purpose thereof is to apply uniformly and conveniently to an object to be applied when batch application of a high-viscosity heat-conductive adhesive is performed. An adhesive application device and an adhesive application method are provided.

  An adhesive applicator of the present invention is for applying a heat conductive adhesive to an object to be applied, and is made of a heat conductive material and includes a mask having a plurality of through holes and a first heating element. , A plurality of nozzles that are projected from the plurality of through-holes toward the back side of the mask while being spaced apart from the application object, and the adhesive is pressed against the surface of the mask and pushed into the plurality of nozzles, respectively. And a squeegee position control unit that controls the position of the squeegee on the mask surface by scanning the squeegee on the mask surface.

  The adhesive coating method of the present invention applies a thermally conductive adhesive to an object to be coated, and has a nozzle for each through hole of a thermally conductive mask having a plurality of through holes from the front surface to the back surface. Mounting the adhesive on the surface of the mask, heating the mask and nozzle, pressing the adhesive against the mask surface with a squeegee and pushing it into the nozzle and scanning the squeegee over the mask surface The process of apply | coating an adhesive agent to an application | coating target object is included.

  In the adhesive application device and the adhesive application method of the present invention, the thermally conductive adhesive is pressed against the mask surface by the squeegee and is respectively pressed into the plurality of nozzles. The adhesive pushed into each nozzle is gradually dropped from the tip of each nozzle onto the application object. Then, the squeegee scans the mask surface, so that the adhesive is applied to the object to be applied. At this time, the first heating element emits heat to heat the mask and each nozzle, and the temperature of these parts rises. As a result, the viscosity of the adhesive is reduced, and adhesion of the adhesive to the squeegee is suppressed. Further, since the entire mask and each nozzle are heated, the viscosity distribution of the heat conductive adhesive is made uniform.

  According to the adhesive application device or the adhesive application method of the present invention, the first heating element is provided on the mask, and the adhesive is applied in a state where the temperature of the mask and each nozzle is increased. And the adhesive can be applied smoothly. Therefore, it can be applied conveniently without bothering the user. In addition, since the entire mask and each nozzle are heated, the viscosity distribution of the adhesive can be made uniform and applied evenly to the application target.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of an adhesive application device according to an embodiment of the present invention. This adhesive application device is for applying the heat-conductive adhesive 5 having a high viscosity as an adhesive 51 on the substrate 2 in accordance with the pattern of each through hole 42 in the metal mask 4. The substrate 2 is installed on a support base 1, and a shaft 3 as a support column that maintains a constant interval is provided between the substrate 2 and the metal mask 4. Further, a squeegee 61 is installed on the surface of the metal mask 4 and is connected to the squeegee position control unit 62.

  The support base 1 is for supporting the substrate 2 as the application object as described above, and the substrate 2 is composed of, for example, an electronic printed circuit board.

  The metal mask 4 is made of a metal material having excellent thermal conductivity such as Al (aluminum), and a plurality of through holes 42 corresponding to the application pattern of the adhesive 5 are provided from the front surface to the back surface. Further, the surface side of the metal mask 4 in each through hole 42 is a widened portion 42A, and a plurality of nozzles 41 protrude from the widened portion 42A toward the substrate 2 side with a predetermined distance from the substrate 2. It is mounted in the manner. These nozzles 41 are made of, for example, SUS (stainless steel). In addition, a pair of silicone rubber heaters 43A and 43B are provided outside the region of the metal mask 4 where the adhesive 5 is applied. The metal mask 4 corresponds to a specific example of the “mask” in the present invention, and is made of a material other than a metal material as long as it is a material having excellent thermal conductivity (thermal conductive material). Also good.

  Here, with reference to FIG. 2, the details of the arrangement of the through holes 42, the nozzle 41, and the heaters 43A and 43B on the metal mask 4 will be described. FIG. 2 is a top view of these arrangements on the metal mask 4.

  In the metal mask 4, a plurality of through holes 42 (and a plurality of nozzles 41) are formed corresponding to the application pattern of the adhesive 5 as described above. Further, the pair of heaters 43A and 43B described above are arranged at both ends of the plurality of through holes 42 (and the plurality of nozzles 41). Further, AC power sources Va and Vb are connected to the heaters 43A and 43B, respectively.

  With such a configuration, the heaters 43A and 43B generate heat according to voltages applied from the AC power sources Va and Vb, respectively, and heat the entire metal mask 4 and each nozzle 41. The heaters 43A and 43B correspond to specific examples of “first heating element” and “plural heating elements” in the present invention.

  Returning to the description of FIG. 1, the squeegee 61 is for pressing the adhesive 5 against the surface of the metal mask 4 while maintaining a slight gap with the metal mask 4. Although details will be described later, the adhesive 5 pressed against the surface of the metal mask 4 in this way is pressed into each nozzle 41. In addition, the squeegee position control unit 61 scans the squeegee 61 on the metal mask 4 (reciprocating operation or one-way operation) as shown by an arrow X1 in FIG. 1 to thereby determine the position of the squeegee 61 on the metal mask 4. It is something to control.

The heat conductive adhesive 5 is composed of, for example, an epoxy adhesive containing alumina (Al ₂ O ₃ ), and as will be described later (FIG. 6 and Table 1), as the temperature increases. It has the property of decreasing the viscosity.

  Next, with reference to FIG. 3 and FIG. 4, the process which coat | covers the adhesive agent 5 on the board | substrate 2 in the adhesive agent coating apparatus which consists of such a structure is demonstrated. Here, FIG. 3 and FIG. 4 respectively show the situation when the adhesive 5 is collectively applied onto the substrate 2 in the adhesive application device of the present embodiment.

  First, as shown in FIG. 3A, when the adhesive 5 is pressed onto the metal mask 4 by the squeegee 61, the thermally conductive adhesive 5 passes from the widened portion 42 </ b> A of each through hole 42 to each nozzle. 41 is pushed into each. Then, the adhesive 5 pushed into each nozzle 41 is gradually dropped from the respective tips onto the surface of the substrate 2. In this way, the adhesive 5 is applied as the adhesive 51 onto the substrate 2 in accordance with the application pattern on the metal mask 4. Further, the heaters 43A and 43B generate heat in accordance with the voltages applied from the AC power sources Va and Vb, respectively, and the entire metal mask 4 and each nozzle 41 are heated, so that the temperature of these parts rises. As a result, the temperature of the adhesive 5 on the metal mask 4 and in each nozzle 41 also rises, and the viscosity of the adhesive 5 decreases. As indicated by the arrow X2, the position of the squeegee 61 is sequentially controlled by the squeegee position control unit 62 (scans over the metal mask 4).

  3B, when the squeegee 61 is scanned from one end to the other end of the metal mask 4 by the squeegee position control unit 62, the adhesive 5 is applied to the entire surface of the substrate 2. Is done.

  Next, as shown in FIG. 4A, when the squeegee 61 returns from the other end of the metal mask 4 to one end, the squeegee 61 rises and tries to leave the thermally conductive adhesive 5 once. At this time, since the viscosity of the adhesive 5 is reduced by the heat generated by the heaters 43A and 43B as described above, the adhesion of the adhesive 5 to the squeegee 61 is suppressed. That is, as in the case of the solder paste 105 shown in FIG. 11C, the adhesive 5 does not adhere to the squeegee 61 and does not protrude outside the application region. Further, since the entire metal mask 4 and each nozzle 41 are heated, the viscosity distribution of the adhesive 5 on the surface of the metal mask 4 becomes uniform, and the adhesive 5 is uniformly applied on the substrate 2.

  Next, as shown by the arrow X4 in FIG. 4B, the squeegee 61 is scanned from the other end to the one end of the metal mask 4 in the same manner as in FIGS. It is applied onto the substrate 2. In this way, by repeating the processes of FIGS. 3A, 3B, 4A, and 4B, the process of collectively applying the adhesive 5 onto the substrate 2 is performed.

  Next, referring to FIG. 5, FIG. 6 and Table 1, the set temperature of the heaters 43A and 43B and the position on the metal mask 4 when the adhesive 5 is collectively applied onto the substrate 2 in this way. An example of the relationship with the viscosity of the corresponding adhesive 5 will be described. Here, FIG. 5 shows the positions of the measurement points P1 to P3 of the viscosity of the adhesive 5 in the top view of the metal mask 4, and Tables 1 and 6 show the heaters 43A, 43A, This represents the relationship between the set temperature of 43B and the viscosity of the adhesive 5 measured at the measurement points P1 to P3. In addition, the graphs G1-G3 shown in FIG. 6 represent the viscosity corresponding to the measurement points P1-P3, respectively.

  As shown in FIG. 5, in this example, the size of the metal mask 4 is 500 mm in the x-axis direction and 250 mm in the y-axis direction. Further, the heaters 43A and 43B are set to 75 mm in the x-axis direction and y-axis direction from the positions (x, y) = (5 mm, 10 mm) and (420 mm, 5 mm), respectively, with the lower left end of the metal mask 4 as the origin. It was arranged with a size of 230 mm. Further, the position of the measurement point P1 is (x, y) = (40 mm, 125 mm), the position of the measurement point P2 is (x, y) = (96 mm, 125 mm), and the position of the measurement point P3 is ( x, y) = (250 mm, 125 mm) (center point of the metal mask 4).

  From Table 1 and FIG. 6, it can be seen that as the set temperature of the heaters 43A and 43B increases, the temperature of the measurement points P1 to P3 also increases, and the viscosity of the adhesive 5 at each measurement point gradually decreases. Moreover, as shown by the dotted line and the arrow X5 in FIG. 6, if the set temperatures of the heaters 43A and 43B are set to 60 ° C. or higher, the viscosities at the respective measurement points P1 to P3 are all 250 Pa · s or lower. I understand. The viscosity value of 250 Pa · s can be regarded as a value equivalent to the viscosity of the solder paste (160 Pa · s). Therefore, by setting the set temperature of the heaters 43A and 43B to 60 ° C. or more, the viscosity of the adhesive 5 at each of the measurement points P1 to P3 is 250 Pa · s or less, and adhesion of the adhesive 5 to the squeegee 61 is suppressed. I understand.

  As described above, according to the present embodiment, the heaters 43A and 43B as the heating elements are provided on the metal mask 4, and the temperature of the entire metal mask 4 and each nozzle 41 is increased, and the heat is applied to the substrate 2. Since the conductive adhesive 5 is applied, adhesion to the squeegee 61 can be suppressed and the adhesive 5 can be applied smoothly. Therefore, it can be applied conveniently without bothering the user.

  Further, since the coating is performed in a state where the entire metal mask 4 and each nozzle 41 are heated, the viscosity distribution of the heat conductive adhesive 5 in the metal mask 4 can be made uniform, and the coating can be applied uniformly to the substrate 2. Become.

  Moreover, since such a heat generating body was comprised with the heater made from a silicone rubber, while being able to attach or detach easily with respect to the metal mask 4, arbitrary shapes can be formed easily.

  Moreover, since it can apply | coat smoothly and convenient with respect to the board | substrate 2, the application | coating efficiency of the adhesive agent 5 can be raised, and it becomes possible to perform high-speed application | coating. Therefore, the throughput of the coating process is improved.

  Furthermore, since the plurality of nozzles 41 are mounted corresponding to the respective through holes 42 of the metal mask 4, the thickness of the metal mask 4 can be increased and the tension can be kept constant, and the metal mask 4 itself Can be reduced. Therefore, the entire adhesive application device can be reduced in size and weight.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made.

  For example, in the above embodiment, the case where the pair of heaters 43A and 43B are arranged at both ends of the metal mask 4 (FIG. 2) has been described. However, the arrangement and quantity of the heaters can be arbitrarily determined according to the application and the like. It is possible to configure. For example, as shown in FIG. 7, four silicone rubber heaters 43 </ b> A to 43 </ b> D may be arranged isotropically around each through hole 42 (and each nozzle 41). In this case as well, as in the above embodiment, the AC power sources Va to Vd are connected to the heaters 43A to 43D, respectively. When a plurality of heaters are arranged isotropically in this way, in addition to the effects in the above embodiment, the temperature distribution of the entire metal mask 4 and each nozzle 41 is made more uniform and the adhesive 5 is applied. The non-uniformity can be further suppressed.

  Moreover, although the said embodiment demonstrated the case where the whole metal mask 4 and the heating means (heating element) of each nozzle 41 were comprised from the heaters 43A and 43B made from silicone rubber, such a heating means (heat generation) The body) may be composed of other things. Specifically, for example, as shown in FIG. 8, a pair of coils 44A and 44B and AC power sources Ve and Vf connected thereto are provided in a metal mask 4 having a certain thickness, and these coils 44A and 44B are provided. You may make it utilize the heat | fever by the electric conduction loss which generate | occur | produces. Further, for example, as shown in FIG. 9, in addition to the heaters 43A and 43B, a heating means (heating element) is also provided on the surface or inside of the squeegee 61 (in the case of FIG. 9, the heater 63 made of silicone rubber). May be.

  Further, for example, as shown in FIG. 10, a pair of temperature sensors 45A and 45B for detecting the temperature of the metal mask 4 on the surface or inside of the metal mask 4, and a heater based on the temperature detected by these temperature sensors 45A and 45B. Temperature control units 46A and 46B for controlling the set temperatures of 43A and 43B are provided, and the set temperature of the heating means (heat generating element) is controlled by control signals S1 and S2 respectively output from these temperature control units 46A and 46B. You may do it. When configured in this way, in addition to the effects in the above-described embodiment, the temperature distribution of the entire metal mask 4 and each nozzle 41 can be made more uniform and kept constant, and unevenness when applying the adhesive 5 can be further increased. It can be further suppressed.

It is a side view showing schematic structure of the adhesive agent coating apparatus which concerns on one embodiment of this invention. It is a top view showing the example of arrangement | positioning of a heater. It is a side view for demonstrating the application | coating process of an adhesive agent. It is a side view for demonstrating the application | coating process of the adhesive agent following FIG. It is a top view for demonstrating the measurement point of the viscosity of an adhesive agent. It is a specific figure showing the relationship between the set temperature of a heater and the viscosity at each measurement point. It is a top view showing the other example of arrangement | positioning of a heater. It is a side view showing schematic structure of the adhesive agent coating apparatus which concerns on a modification. It is a side view showing schematic structure of the adhesive agent coating apparatus which concerns on a modification. It is a side view showing schematic structure of the adhesive agent coating apparatus which concerns on a modification. It is a side view for demonstrating the application | coating process of the conventional adhesive agent. It is a side view for demonstrating the application | coating process of the conventional adhesive agent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Support stand, 2 ... Board | substrate, 3 ... Shaft, 4 ... Metal mask, 41 ... Nozzle, 42 ... Through-hole, 42A ... Widening part, 43A-43D, 63 ... Heater, 44A-44D ... Coil, 45A, 45B ... Temperature sensor, 46A, 46B ... Temperature controller, 5 ... Adhesive, 51 ... Adhesive, 61 ... Squeegee, 62 ... Squeegee movement controller, X1-X4 ... Moving direction of squeegee, Va-Vd ... AC power supply, P1- P3: Measurement point, S1, S2: Control signal.

Claims (8)

An apparatus for applying a thermally conductive adhesive to an application object,
A mask made of a thermally conductive material and having a plurality of through holes and a first heating element;
A plurality of nozzles formed to protrude from the plurality of through-holes toward the back side of the mask while being separated from the application target;
A squeegee for pressing the adhesive against the surface of the mask and pressing the adhesive into the plurality of nozzles;
An adhesive coating apparatus comprising: a squeegee position controller that controls the position of the squeegee on the mask surface by scanning the squeegee on the mask surface. The adhesive application device according to claim 1, wherein a second heating element is disposed on a surface or inside of the squeegee. The adhesive application device according to claim 1, wherein the first heating element is constituted by a heater made of silicone rubber. The mask has a coil;
The adhesive application device according to claim 1, wherein the first heating element is configured by the coil. The adhesive application device according to claim 1, wherein the first heating element includes a plurality of heating elements, and the plurality of heating elements are arranged isotropically on the mask surface. A temperature sensor for detecting the temperature of the mask;
The adhesive coating apparatus according to claim 1, further comprising: a temperature control unit that controls a temperature of the first heating element based on a temperature detected by the temperature sensor. The temperature of the said 1st heat generating body is set to 60 degree | times or more. The adhesive agent coating apparatus of Claim 1 characterized by the above-mentioned. A method of applying a thermally conductive adhesive to an application object,
Attaching a nozzle to each of the through holes of the thermally conductive mask having a plurality of through holes from the front surface to the back surface, disposing the adhesive on the surface of the mask, and heating the mask and the nozzles; ,
Applying the adhesive to the application object by pressing the adhesive against the mask surface with a squeegee and pushing it into the nozzle and scanning the squeegee with the mask surface. Adhesive application method.

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