Patent Application
20120188733
The present invention relates to a substrate mounting structure, a display device equipped therewith, and a substrate mounting method.
A technique for mounting an electronic component such as an IC chip on a surface of a substrate using an adhesive material for pressure bonding has been known in the past (for example, see Patent Document 1). A conventional substrate mounting method will be briefly described below.
As a conventional substrate mounting method, a film-form pressure-bonding adhesive material (thermosetting adhesive material) is first disposed on a surface of a substrate. Then, an electronic component is disposed on the surface of the substrate via this pressure-bonding adhesive material.
Next, heat is applied to a prescribed pressing member, and the electronic component is pressed toward the surface of the substrate by the heated pressing member. At this point, because heat is applied to the pressure-bonding adhesive material, the pressure-bonding adhesive material is hardened. That is, a state is created in which the electronic component is thermocompression-bonded to (mounted on) the surface of the substrate via the hardened pressure-bonding adhesive material.
Incidentally, an elastic body composed of rubber or the like is used as the pressing member used in a thermocompression bonding step in a conventional substrate mounting method. The reason for using such an elastic body in a thermocompression bonding step is to compensate for a difference in the heights of electronic components in cases where a plurality of electronic components with mutually different heights are simultaneously thermocompression-bonded to a surface of a substrate.
However, in the aforementioned conventional substrate mounting method, when a plurality of electronic components are simultaneously thermocompression-bonded to the surface of a substrate, a disadvantage arises in that the electronic components are shifted from the desired positions.
For example, as is shown in
The aforementioned disadvantage arises with the conventional substrate mounting method, so the resulting problem is that reliability is lowered.
The present invention was devised in order to solve the aforementioned problem, and an object thereof is to provide a substrate mounting structure, a display device, and a substrate mounting method which can increase reliability.
In order to achieve the object described above, the substrate mounting structure according to a first aspect of the present invention includes a substrate; a pressure-bonding adhesive material disposed on a surface of the substrate; and an electronic component mounted on the surface of the substrate via the pressure-bonding adhesive material and disposed in a first region of a surface area of the substrate. Furthermore, prescribed objects are respectively disposed in a second region adjacent to one side of the first region and in a third region adjacent to the other side of the first region which is opposite from this one side so that the electronic component is sandwiched by these prescribed objects.
In the substrate mounting structure according to the first aspect, by virtue of the configuration as described above, it is possible to suppress the positional shifting of the electronic component in horizontal directions (directions parallel to the surface of the substrate) during a mounting step in which the electronic component is mounted on the surface of the substrate. This effect will be described in detail below. Note that the mounting of the electronic component on the surface of the substrate is performed by disposing the electronic component on the surface of the substrate via the pressure-bonding adhesive material (e.g., thermosetting adhesive material) and then pressing the electronic component toward the surface of the substrate with a pressing member (elastic body), thus thermocompression bonding the electronic component to the surface of the substrate.
Specifically, in the substrate mounting structure according to the first aspect, in a state in which the electronic component disposed in the first region is sandwiched by the prescribed objects, this electronic component disposed in the first region can be pressed by the pressing member during the mounting step. Therefore, when the electronic component in the first region is pressed by the pressing member, the pressing force applied to the electronic component in the first region from the side of the second region (pressing force from a portion of the pressing member that has entered between the electronic component in the first region and the prescribed object in the second region) and the pressing force applied to the electronic component in the first region from the side of the third region (pressing force from a portion of the pressing member that has entered between the electronic component in the first region and the prescribed object in the third region) become substantially the same. Consequently, the positional shifting of the electronic component disposed in the first region in horizontal directions is suppressed.
Here, for instance, in cases where no prescribed object is disposed in one of the second region and the third region (e.g., second region) and a prescribed object is disposed only in the other of the second region and the third region (e.g., third region), a state is created in which there is an open space on the side of the second region as seen from the electronic component in the first region, and there is a prescribed object on the side of the third region. Therefore, the balance between the pressing force applied to the electronic component in the first region from the side of the second region and the pressing force applied to the electronic component in the first region from the side of the third region is lost, so the electronic component in the first region ends up positionally shifted in a horizontal direction (direction toward the second region). In such cases, a similar disadvantage arises whether the number of the electronic components disposed in the first region is one or plural.
Moreover, in cases where no prescribed object is disposed in the second region nor in the third region and a plurality of electronic components are disposed in the first region (arranged from the side of the second region toward the third region), if attention is focused on one of the electronic components located at the row ends in the electronic component row, a state is created in which there is an open space on the outside (on the second region side or on the third region side) as seen from this electronic component at an end of the row, while there is another electronic component on the other side of this electronic component. Therefore, the balance between the pressing force applied to the electronic component at the row end from the outside (the second region side or the third region side) and the pressing force applied to the electronic component at the row end from the opposite side thereof is lost, so the electronic component at the end of the row ends up positionally shifted in a horizontal direction (direction toward the second region or third region). Note that the disadvantage in such cases does not arise if the number of the electronic components disposed in the first region is one.
Thus, with the substrate mounting structure according to the first aspect, it is possible to suppress the positional shifting of the electronic components mounted on the surface of the substrate, thus making it possible to improve reliability.
In the substrate mounting structure according to the aforementioned first aspect, at least the prescribed object disposed in the second region is preferably a dummy component. By adopting such a configuration, the positional shifting of the dummy component occurs in a horizontal direction, but because the dummy component is a component that is not electrically connected to another component, there is no effect on the reliability.
In the substrate mounting structure according to the aforementioned first aspect, the prescribed object disposed in the third region may be a dummy component and may also be an electronic component different from the electronic component disposed in the first region. Furthermore, this prescribed object may also be an opposite substrate disposed so as to face the substrate.
In the substrate mounting structure according to the aforementioned first aspect, when among directions parallel to the surface of the substrate, a direction from the side of the second region toward the third region is taken as a first direction, a plurality of electronic components may also be arranged in the first region along the first direction.
In addition, when among directions parallel to the surface of the substrate, a direction perpendicular to the first direction is taken as a second direction, a plurality of electronic components may also be arranged in the first region in a matrix along the first direction and second direction. In this case, it is preferable that prescribed objects be further respectively disposed in a pair of regions adjacent to the first region in the second direction. If such a configuration is adopted, it is possible to suppress the positional shifting of the plurality of electronic components disposed in the first region in the first direction and also to suppress the positional shifting of the plurality of electronic components disposed in the first region in the second direction.
In the substrate mounting structure according to the aforementioned first aspect, the pressure-bonding adhesive material is preferably an anisotropic conductive film. By adopting such a configuration, it is possible to mount the electronic component(s) easily on the surface of the substrate.
The display device according to a second aspect of the present invention includes the substrate mounting structure according to the aforementioned first aspect. Such a configuration makes it possible to easily improve the reliability of the substrate mounting structure within the display device.
The substrate mounting method according to a third aspect of the present invention includes: preparing a substrate and disposing a pressure-bonding adhesive material on a surface of the substrate; disposing an electronic component in a first region of a surface are of the substrate via the pressure-bonding adhesive material; and thermocompression bonding the electronic component in the first region by pressing the electronic component toward the surface of the substrate with a pressing member. Furthermore, this substrate mounting method further includes, prior to the step of thermocompression bonding the electronic component in the first region, respectively disposing prescribed objects in a second region adjacent to one side of the first region and in a third region adjacent to the other side of the first region which is opposite from the one side, and when the electronic component is thermocompression-bonded in the first region, the electronic component and the prescribed objects are simultaneously pressed toward the surface of the substrate by the pressing member.
With the substrate mounting method according to the third aspect, as a result of the electronic component being mounted on the surface of the substrate through the aforementioned steps, the positional shifting of the electronic component in horizontal directions can be suppressed, so reliability can be improved.
In the substrate mounting method according to the aforementioned third aspect, it is more preferable that at least the prescribed object disposed in the second region be a dummy component.
In the substrate mounting method according to the aforementioned third aspect, it is more preferable that the interspace between the prescribed object disposed in the second region and the electronic component disposed in the first region and the interspace between the prescribed object disposed in the third region and the electronic component disposed in the first region be set to be the same size. If such a configuration is adopted, the pressing force applied to the electronic component in the first region from the side of the second region and the pressing force applied to the electronic component in the first region from the side of the third region can be made substantially the same.
Thus, with the present invention, it is possible to easily improve reliability.
The substrate mounting structure according to a first embodiment will be described below with reference to
In the first embodiment, a glass substrate 1 having connection terminals (not illustrated) on a surface 1a is used. Note that the glass substrate 1 is one example of the “substrate” of the present invention, and a PWB (Printed Wiring Board), FPC (Flexible Printed Circuit), or the like may also be used.
An ACF (Anisotropic Conductive Film) 2 which is a pressure-bonding adhesive material (thermosetting adhesive material) is disposed on the surface 1a of the glass substrate 1. This ACF 2 is composed of a thermosetting resin having conductive particles mixed therein and has conductive properties with respect to a direction perpendicular to the surface 1a of the glass substrate 1 while having insulation properties with respect to directions parallel to the surface 1a of the glass substrate 1 (directions including the X direction and Y direction). Note that the X direction is a direction from the side of a dummy component mounting region 10b (described later) toward the side of a dummy component mounting region 10c (described later), while the Y direction is a direction perpendicular to the X direction.
Furthermore, an SMD (Surface Mount Device) 3 is mounted on the surface 1a of the glass substrate 1 via the ACF 2. That is, the SMD 3 is firmly fixed to the surface 1a of the glass substrate 1 by the ACF 2. Note that the SMD 3 is one example of the “electronic component” of the present invention, and examples include a resistor, capacitor, diode, and the like.
A plurality (e.g., two) of these SMDs 3 are present and are disposed on the surface 1a of the glass substrate 1 in a prescribed region 10a thereof, being lined up along the X direction. Note that the prescribed region 10a is one example of the “first region” of the present invention and is referred to as the SMD mounting region 10a in the following description.
Here, in the first embodiment, dummy components 4 that are not electrically connected to another component are also mounted on the surface 1a of the glass substrate 1 via the ACF 2 in addition to the SMDs 3. In concrete terms, a region adjacent to one side of the SMD mounting region 10a in the X direction and a region on the other side thereof (on the side opposite from the one side) respectively constitute dummy component mounting regions 10b and 10c in which the dummy components 4 are respectively mounted. Then, one dummy component 4 is disposed in each of the dummy component mounting regions 10b and 10c. That is, in the first embodiment, a state is created in which the two SMDs 3 are sandwiched between the two dummy components 4. Note that the dummy components 4 are one example of the “prescribed objects” of the present invention. Moreover, the dummy component mounting regions 10b and 10c are examples of the “second region” and “third region,” respectively, of the present invention.
The dummy components 4 that are disposed respectively in the dummy component mounting regions 10b and 10c are composed of components of the same structure as the SMDs 3. That is, resistors, capacitors, diodes, or the like are used as the dummy components 4. Note that the SMDs 3 and the dummy components 4 are preferably the same components with respect to each other, but these may also be different components from each other. In addition, in cases where the cost is taken into account, it is preferable that resistors which are inexpensive components be used as the dummy components 4.
The substrate mounting structure according to the first embodiment is configured as described above. Furthermore, this substrate mounting structure is manufactured through the following manufacturing process:
Specifically, as is shown in
In this case, in the first embodiment, two SMDs 3 are disposed in the SMD mounting region 10a, and one dummy component 4 each is disposed in each of the dummy component mounting regions 10b and 10c that are adjacent to this SMD mounting region 10a in the X direction. In addition, these four components (two SMDs 3 and two dummy components 4) are lined up in a single row so as to mutually face the same direction and also so as to have equally-spaced intervals along the X direction.
Then, as is shown in
At this point, the ACF 2 is heated and is therefore hardened in a state in which this ACF 2 is tightly adhered to the surface 1a of the glass substrate 1 and the SMDs 3 and dummy components 4. That is, the SMDs 3 and dummy components 4 are thermocompression-bonded to (mounted on) the surface 1a of the glass substrate 1 via the ACF 2. As a result, the substrate mounting structure of the first embodiment shown in
Note that if the aforementioned manufacturing method is used, there is a risk of the mounting components being shifted significantly from the desired positions depending on the number of the mounting components to be mounted during the thermocompression bonding step (step shown in
For example, in cases where there is one SMD 3 as the mounting component, with no other mounting components nearby as shown in
Meanwhile, in cases where a plurality of (e.g., three) SMDs 3 are lined up in a single row in the X direction as shown in
Furthermore, in cases where the number of mounting components to be mounted is two (see
When these are taken into account, with the aforementioned configuration of the first embodiment (see
In the first embodiment, by adopting the configuration as described above, it is possible to suppress the positional shifting of the SMDs 3 mounted on the surface 1a of the glass substrate 1, so reliability can be improved.
Moreover, with the aforementioned configuration of the first embodiment, even if three or more SMDs 3 are disposed in the SMD mounting region 10a as shown in
In addition, in the aforementioned configuration of the first embodiment, if two or more dummy components 4 are disposed in each of the dummy component mounting regions 10b and 10c as shown in
Next, an experiment conducted in order to confirm the aforementioned effects of the first embodiment will be described.
In this confirmation experiment, two types of substrate mounting structure were respectively created using the manufacturing method of the first embodiment and a conventional manufacturing method, with the substrate mounting structure created using the manufacturing method of the first embodiment being taken as a working example (see
In Table 1 and Table 2 below, the desired mounting position is assumed to be 0 μm. Furthermore, in Table 1 and Table 2 below, among the SMDs 3 shown in each of
Referring to Table 1 and
In contrast, referring to Table 2 and
From these results, it was possible to confirm that the positional shifting of the SMDs 3 in horizontal directions was suppressed with the configuration of the first embodiment.
Note that in the confirmation experiment described above, size 1005 SMDs were used, and the interspace between adjacent SMDs was set at 0.3 mm. Then, thermocompression bonding was performed with a force of 400N by means of a pressing member composed of rubber (hardness: 80).
The substrate mounting structure according to a second embodiment will be described below with reference to
In this second embodiment, in the aforementioned configuration of the first embodiment, a plurality of (e.g., six) SMDs 3 are mounted in the SMD mounting region 10a on the surface 1a of the glass substrate 1, with the plurality of SMDs 3 being arranged in a matrix (in the X direction and Y direction). Then, a plurality of dummy components 5 are mounted on the surface 1a of the glass substrate 1 in prescribed regions thereof so as to surround from four directions a collected body containing the plurality of SMDs 3.
Specifically, in the second embodiment, a region adjacent to one side of the SMD mounting region 10a in the X direction and a region on the other side thereof respectively constitute dummy component mounting regions 10b and 10c, and a region adjacent to one side of the SMD mounting region 10a in the Y direction and a region on the other side thereof also constitute dummy component mounting regions 10d and 10e, respectively. Then, one dummy component 5 is disposed in each of the dummy component mounting regions 10b to 10e. Note that the dummy components 5 are one example of the “prescribed objects” of the present invention.
Incidentally, in this embodiment, the length in the Y direction of the dummy components 5 respectively disposed in the dummy component mounting regions 10b and 10c is set at a length equal to or longer than the length from the outer end of the SMDs 3 located at one end in the Y direction to the outer end of the SMDs 3 located at the other end. Furthermore, the length in the X direction of the dummy components 5 respectively disposed in the dummy component mounting regions 10d and 10e is set at a length equal to or longer than the length from the outer end of the SMDs 3 located at one end in the X direction to the outer end of the SMDs 3 located at the other end. Moreover, the height of the dummy components 5 (the amount of protrusion from the surface 1a of the glass substrate 1) is set at 1 mm or more and also within ±0.3 mm of the height of the SMDs 3 (the amount of protrusion from the surface 1a of the glass substrate 1).
In the second embodiment, by adopting the configuration as described above, in cases where a plurality of SMDs 3 are arranged in a matrix (in the X direction and Y direction), the positional shifting of the plurality of SMDs 3 in the X direction can be suppressed, and the positional shifting of the plurality of SMDs 3 in the Y direction can also be suppressed.
In addition, in the second embodiment, by using the dummy components 5 that are set to have dimensions as described above, the positional shifting of the plurality of SMDs 3 in horizontal directions can be reliably suppressed.
The substrate mounting structure and substrate mounting method according to a third embodiment will be described below with reference to
A glass substrate 31 of the third embodiment is a TFT substrate into which thin-film transistors are fabricated and is used for the liquid crystal panel of a liquid crystal display device (display device). Specifically, another glass substrate (CF substrate into which a color filter is fabricated) 36 is disposed on a surface 31a of this glass substrate 31, and a liquid crystal layer (not illustrated) is sandwiched between the glass substrate 31 and the glass substrate 36. Note that the glass substrate 31 is one example of the “substrate” of the present invention. Furthermore, the glass substrate 36 is one example of the “prescribed object” and “opposite substrate” of the present invention.
Although the glass substrates 31 and 36 are thus superimposed on one another, a portion of the surface 31a of the glass substrate 31 is exposed from the glass substrate 36. Then, SMD mounting regions 30a are provided within the exposed area of the surface 31a of the glass substrate 31, and SMDs 33 are respectively mounted via an ACF 32 (see
Then, in the third embodiment, regions respectively adjacent to one side of the SMD mounting regions 30a in the X direction constitute dummy component mounting regions 30b, and dummy components 35 are respectively mounted via the ACF 32 in these dummy component mounting regions 30b. In addition, no other mounting component is mounted in regions 30c respectively adjacent to the other side of the SMD mounting regions 30a in the X direction, so there is an edge 36a of the glass substrate 36. Therefore, in the third embodiment, a state is created in which each of the SMDs 33 is sandwiched between the glass substrate 36 (edge 36a) and the corresponding dummy component 35. Note that the dummy components 35 are one example of the “prescribed objects” of the present invention. Furthermore, the dummy component mounting regions 30b are one example of the “second region” of the present invention. Moreover, the regions 30c in which the glass substrate 36 (edge 36a) is located are one example of the “third region” of the present invention.
Incidentally, the height of the dummy components 35 (the amount of protrusion from the surface 31a of the glass substrate 31) that are used in this embodiment is set at 0.1 mm or more and also within ±0.3 mm with respect to the height position of the upper surface of the glass substrate 36 (the surface on the opposite side of the surface toward the glass substrate 31). In addition, the length of the dummy components 35 in the Y direction is set so as to be equal to or longer than the lengths of the SMDs 33 in the Y direction. Note that the length of the dummy components 35 in the Y direction may also be shorter than the lengths of the SMDs 33 in the Y direction as long as this length is equal to or longer than a half the lengths of the SMDs 33 in the Y direction.
In the third embodiment, effects similar to those of the first embodiment can be obtained by adopting the configuration as described above.
Specifically, as is shown in
In the third embodiment, furthermore, the positional shifting of the SMDs 33 in horizontal directions can be reliably suppressed by using the dummy components 35 that are set to have dimensions as described above.
The substrate mounting structure and substrate mounting method according to a fourth embodiment will be described below with reference to
In this fourth embodiment, in the aforementioned configuration of the third embodiment, focusing attention on the SMD mounting regions 30a to which the reference character A is added, dummy components 35 are respectively disposed in dummy component mounting regions 30b which are regions respectively adjacent to one side of the SMD mounting regions 30a-A in the X direction, while an IC component (electronic component other than the SMDs 33) 37 is disposed in a region 30c adjacent to the other side of the SMD mounting regions 30a-A in the X direction. That is, the SMDs 33 disposed in the SMD mounting regions 30a-A are in a state of being sandwiched between the dummy components 35 and the IC component 37. Note that the IC component 37 is one example of the “prescribed object” of the present invention.
Moreover, focusing attention on the SMD mounting region 30a to which the reference character B is added, the SMD 33 disposed in this SMD mounting region 30a-B is in a state in which this SMD 33 is sandwiched in the X direction between the glass substrate 36 (edge 36a) and a dummy component 35 and sandwiched in the Y direction between the IC component 37 and a dummy component 35. Specifically, a dummy component 35 is disposed in a region (dummy component mounting region) 30b adjacent to one side of the SMD mounting region 30a-B in the X direction, while the glass substrate 36 (edge 36a) is disposed in a region 30c adjacent to the other side of the SMD mounting region 30a-B in the X direction. In addition, a dummy component 35 is disposed in a region 30d adjacent to one side of the SMD mounting region 30a-B in the Y direction, while the IC component 37 is disposed in a region 30e adjacent to the other side of the SMD mounting region 30a-B in the Y direction.
The remaining configuration of the fourth embodiment is the same as that of the third embodiment, so a description thereof is omitted.
In the fourth embodiment, effects similar to those of the first embodiment can be obtained by adopting the aforementioned configuration.
Specifically, looking at the SMDs 33 disposed in the SMD mounting regions 30a-A, during the thermocompression bonding step using the elastic body 12 as the pressing member as shown in
Note that during this thermocompression bonding step, the respective interspaces W1 between the SMDs 33 disposed in the SMD mounting regions 30a-A and the IC component 37 and the respective interspaces W2 between these SMDs 33 and the corresponding dummy components 35 in the X direction are set to be substantially the same. Moreover, the interspace between the SMD 33 disposed in the SMD mounting region 30a-B and the glass substrate 36 and the interspace between this SMD 33 and the corresponding dummy component 35 in the X direction are set to be substantially the same, and the interspace between the SMD 33 disposed in the SMD mounting region 30a-B and the IC component 37 and the interspace between this SMD 33 and the corresponding dummy component 35 in the Y direction are set to be substantially the same.
Here, in the aforementioned configuration of the fourth embodiment, as is shown in
The embodiments disclosed herein should be considered as exemplification and not as restrictive in any respect. The scope of the present invention is indicated not by the aforementioned description of the embodiments, but by the scope of the claims, and shall include all modifications with meanings equivalent to those of the scope of the claims and within the scope thereof.
For instance, an ACF was used in the aforementioned embodiments, but the present invention is not limited to this; an NCF (Non-Conductive Film) may also be used, or a pressure-bonding adhesive material other than these may also be used.
In addition, in the aforementioned embodiments, the pressing member (elastic body) was heated during thermocompression bonding, but the present invention is not limited to this; it would also be possible to apply heat from the substrate side.
Furthermore, a state is also created in which SMDs are sandwiched only by components other than dummy components.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-231177 | Oct 2009 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/058172 | 5/14/2010 | WO | 00 | 3/29/2012 |
