Patent Application
20070253148
Hereinafter, embodiments of the present invention are explained below according to a set of drawings showing how the embodiments apply to a portable computer.
The display unit 3 includes a display housing 6 and a liquid crystal display (LCD) panel 7 housed inside the display housing 6. The LCD panel 7 has a display screen 7a. The display screen 7a is exposed on the outside of the display housing 6 via an opening 6a provided on the front side of the display housing 6.
The display unit 3 is supported via hinge devices at the rear end of the enclosure 4. Therefore, the display unit 3 is rotatably movable between the closed position to which it moves in a manner collapsing onto the top wall 4a from above to cover the top wall 4a, and the erected position where the top wall 4a and display screen 7a are both exposed.
As shown in
As shown in
The insulating substrate 21 is formed by reinforced material such as glass fabric, into which another material with insulation property such as phenol resin, epoxy resin, polyimide or BT resin is impregnated. As shown in
The pad 23 and conductive wiring pattern 24 are provided on the surface of the insulating substrate 21. The pad 23 and conductive wiring pattern 24 are formed by conductor material such as copper foil. As shown in
The plurality of pads 23 are classified into first through third pads 23a, 23b, 23c based on the purposes for which they are used. The first pad 23a may be a power supply pad, for instance, that supplies power to the circuit component 12. The second pad 23b may be a signal line pad, for instance, that exchanges signals with the circuit component 12. In this embodiment, the third pad 23c is an idle pad that is not electrically connected to the circuit component 12.
The conductive wiring pattern 24 is connected to the pad 23. The conductive wiring pattern 24 may be an inter-pad connection pattern, for instance. The plurality of conductive wiring patterns 24 are classified into first and second conductive wiring patterns 24a, 24b based on the purposes for which they are used.
The first conductive wiring pattern 24a is connected to the first pad 23a. The first conductive wiring pattern 24a electrically connects the first pad 23a to the power supply. The second conductive wiring pattern 24b is connected to the second pad 23b. The second conductive wiring pattern 24b electrically connects the second pad 23b to other second pad 23b, for instance. The conductive wiring patterns 24 can have various widths according to the purposes for which they are used. For example, the first conductive wiring pattern 24a is wider than the second conductive wiring pattern 24b.
As shown in
Further, the pad 23 conforming to this embodiment is explained in details. As shown in
The extension part 34 extends from a part of the pad body 33 toward the opening rim 31a of the opening 31. The edge of the extension part 34 reaches the opening rim 31a and connects to the opening rim 31a.
The extension parts 34 of the first and second pads 23a, 23b are provided in a manner corresponding to the lead-out directions of the first and second conductive wiring patterns 24a, 24b, respectively. As shown in
That is to say, the pad 23 is formed in a shape conforming to the opening rim 31a in the solder resist 26 and has a groove (that is, a part where no conductor layer is provided) between a part of the pad 23 and the opening rim 31a.
As shown in
The extension part 34 is also provided in the third pad to which a conductive wiring pattern 24 is not connected.
The pad area of each of the first through third pads 23a, 23b, 23c (that is, the area of conductor layer to which a bump is attached), is evaluated based on the total sum of area A of the pad body 33 of each pad 23 and area B of the pad's extension part 34 (A+B). In the printed wiring board 11, the extension part 34 of the first pad 23a, extension part 34 of the second pad 23b and extension part 34 of the third pad 23c all have the same area.
In other words, when the area of the first pad 23a (pad body 33, extension part 34) is given by (A1, B1), area of the second pad 23b (pad body 33, extension part 34) by (A2, B2), and area of the third pad 23c (pad body 33, extension part 34) by (A3, B3), then the equation A1+B1=A2+B2=A3+B3 works out. That is to say, the first through third pads 23a, 23b, 23c all have the same pad area.
Each conductive wiring pattern 24 is laid out in such a way that the gap g of a pad 23 to which the conductive wiring pattern is not connected is disposed between the conductive wiring pattern and the pad. In other words, a conductive wiring pattern 24 is drawn so that it runs alongside the gap g of a pad 23. It means that a conductive wiring pattern 24 is arranged in such a way that it does not run alongside the extension part 34 of a pad 23. For example, as shown in
As shown in
For instance, there is no need to change the design of bumps 42 and pads 23 when changing the semiconductor elements installed in the package body 41 to elements of different types. In this embodiment, the bumps 42 corresponding to the third pads 23c on the printed wiring board 11 are not electrically connected to the semiconductor elements, but they remain idle instead. One example of bump 42 is solder ball. Note that the bumps 42 need not be always provided on the circuit component 12. For example, they are provided on the printed wiring board 11 in the case of a LGA package.
As shown in
The operation of the portable computer 1 is explained.
All of the plurality of bumps 42 have the same size. In other words, the bumps 42 have a specified standard size that does not change according to the number or sizes of conductive wiring patterns 24 connected to the individual pads 24.
All of the plurality of pads 23 conforming to this embodiment have the same pad area regardless of the sizes or number of conductive wiring patterns 24 connected to the individual pads 23. As a result, the bumps 42 connected to the pads 23 have the same bonded state.
When the printed circuit board 5 of this configuration is used, the bonded state of each bump 42 with a pad 23 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the pad 23.
In other words, connecting a conductive wiring pattern 24 to a pad having a gap along the opening rim 31a in the solder resist 26 (that is, a pad that only has a pad body 33 in this embodiment) changes the pad area only by the area of the conductive wiring pattern.
The pad 23 conforming to this embodiment has an extension part 34 in addition to its pad body 33. In other words, the pad area is initially larger than the pad that only has its pad body 33. For this reason, change in the pad area by the area of the conductive wiring pattern translates to a smaller rate of change in the pad area compared to the aforementioned pad. That is to say, the pad 23 conforming to this embodiment provides a large initial pad area and thereby suppresses the rate of change in the area due to the effect of any conductive wiring pattern connected to it.
Accordingly, when bumps 42 having the same size are used for respective pads 23, the variation in bonded state among the pads 23 can be reduced. In other words, the bonded state of each bump 42 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the applicable pad 23. Because the bonded state of bump 42 does not vary much, the problem of non-connection (so called “unsoldered state”) or weak bonded state caused by deformation of bump 42 can be reduced, and a stable bonded state can be formed as a result.
When a gap g is provided between the pad body 33 of a pad 23 and the opening rim 31a, a bump 42 can be bonded three-dimensionally to the pad 23. In other words, the pad 23 conforming to this embodiment can form a more stable bonded state through improved bump bonding strength (share strength, for example).
When pads 23 are arranged in such a way that their gaps g are aligned side by side, it becomes possible to provide a sufficient pad area while maintaining at least a specified distance between the adjacent conductor layers. Specifically, providing an extension part 34 increases the pad area. However, if the extension part 34 extends in the direction toward other adjacent pad 23 closest to the applicable pad, then the conductor layer of this extension part 34 becomes very close to the conductor layer of such other pad 23. This is not favorable in view of a narrower pad pitch.
However, the distance between the conductor layer of an extension part 34 and the conductor layer of other pad 23 can be increased by means of forming a gap g (that is, a part where no conductor layer is provided) separately from the extension pad 34 and aligning these gaps g side by side. Thus, the plurality of pads 23 of a larger pad area can be arranged with a narrow pitch (that is, they can be arranged densely).
By allowing the conductive wiring pattern 24 to be connected to the extension part 34, the bonded state of each bump 42 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the applicable pad 23. For example, the conductive wiring pattern 24 conforming to this embodiment is entirely covered with the solder resist 26. In other words, the area of conductor layer connected to each bump 42 is not affected by the sizes or number of conductive wiring patterns 24. Because the pad area does not change, the bonded state between a pad 23 and a bump 42 remains almost uniform.
In particular, a uniform bonded state can be achieved among all pads 23 if the total sum of the area of the pad body 33 and the area of the extension part 34 is the same among all pads 23.
If the conductive wiring pattern 24 is laid out in such a way that it runs alongside the gap g, a clearance can be ensured between the conductor layer of the conductive wiring pattern 24 and that of the pad 23 even when the conductive wiring pattern 24 and pad 23 are arranged very close to each other. In other words, the conductive wiring pattern 24 and pad 23 can be densely arranged.
Each extension part 34 in this embodiment extends to the opening rim 31a. However, the extension part 34 need not always extend to the opening rim 31a. If this is the case, a part of the tip of the applicable conductive wiring pattern 24 is exposed within the opening 31. Each extension part 34 only needs to be provided in a manner ensuring an appropriate pad area, and its shape is not specifically limited. However, extending the extension part 34 to the opening rim 31a makes it easier to ensure a larger pad area. The bump 42 conforming to this embodiment need not be bonded three-dimensionally to the pad 23. Instead, the bump 42 may be bonded only to the top surface 36 of the pad 23.
A portable computer 51 is explained by referring to
The enclosure 4 of the portable computer 51 houses a printed circuit board 52 inside. The printed circuit board 52 has a printed wiring board 53 and a circuit component 12 on which bumps 42 are provided. The printed wiring board 53 has pads 23 provided on an insulating substrate 21. The pads 23 on the printed wiring board 53 include a pad 23b to which one conductive wiring pattern 24 is connected, a pad 23b′ to which two conductive wiring patterns 24 are connected, and a pad 23b″ to which four conductive wiring patterns 24 are connected.
As shown in
If one extension part 34 of the pad 23b′ has area B2′, one extension part 34 of the pad 23b″ has area B2″, and the pad body 33 of each pad has the same area A, then the equation B2=2×B2′=4×B2″ works out. In other words, the pads 23b, 23b′ 23b″ all have the same pad area.
When the printed circuit board 52 of this configuration is used, the bonded state of each bump 42 with a pad 23 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the pad 23, and a stable bonded state can be formed as a result. In other words, providing an extension part or parts 34 on the pad 23 reduces the rate of change in the pad area due to the effect of any conductive wiring pattern 24 connected to the pad. This makes the bonded state of bump 42 roughly uniform among individual pads 23.
According to the printed circuit board 52 conforming to this embodiment, conductive wiring patterns 24 are connected to extension parts 34 and therefore the area of each pad does not change due to the effect of any conductive wiring pattern 24 connected to it, and consequently a more uniform bonded state can be achieved. In particular, the bonded state becomes uniform among all pads 23 as long as all pads 23 have the same area, which is the case of this embodiment.
A portable computer 61 is explained by referring to
The enclosure 4 of the portable computer 61 houses a printed circuit board 62 inside. The printed circuit board 62 has a printed wiring board 63 and a circuit component 12 on which bumps 42 are provided. The printed wiring board 63 has pads 23 provided on an insulating substrate 21.
As shown in
The four extension parts 34 are arranged along the periphery of the pad body 33 at an equal interval from each other. The four extension parts 34 are provided in the directions in which conductive wiring patterns 24 will be led out. In this embodiment, some of the extension parts 34 are not connected to conductive wiring patterns 24 but remain idle instead.
As shown in
When the printed circuit board 62 of this configuration is used, the bonded state of each bump 42 with a pad 23 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the pad 23, and a stable bonded state can be formed as a result. In other words, providing extension parts 34 on the pad 23 reduces the rate of change in the pad area due to the effect of any conductive wiring pattern 24 connected to the pad. This makes the bonded state of bump 42 roughly uniform among individual pads 23. According to the printed circuit board 62 conforming to this embodiment, conductive wiring patterns 24 are connected to extension parts 34 and therefore the area of each pad does not change due to the effect of any conductive wiring pattern 24 connected to it, and consequently a more uniform bonded state can be achieved.
In the layout design of this printed wiring board 63, pads 23 and conductive wiring patterns 24 are designed in separate processes, respectively. The pad 23 conforming to this embodiment has a plurality of extension parts 34 arranged all around the pad body 33 at an equal interval from each other. If this pad shape is used as a standard design, it can support various conductive wiring patterns 24. In other words, all that needs to be done in the layout design of a printed wiring board 63 is to design conductive wiring patterns 24 corresponding to the circuit component to be installed, and there is no need to design pads.
A portable computer 71 is explained by referring to
The enclosure 4 of the portable computer 71 houses a printed circuit board 72 inside. The printed circuit board 72 has a printed wiring board 73 and a circuit component 12 on which bumps 42 are provided. The printed wiring board 73 has a plurality of pads 23 provided on an insulating substrate 21. As shown in
When the printed circuit board 72 of this configuration is used, the bonded state of each bump 42 with a pad 23 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the pad 23. The pad 23 conforming to this embodiment changes its pad area when conductive wiring patterns 24 are connected to it. Even when the pad area changes as a result of connection of conductive wiring patterns 24, however, the pad 23 initially has a larger area by virtue of extension parts 34 and therefore the rate of change in the pad area is kept small. This makes the bonded state of bump 42 roughly uniform among individual pads 23.
The pad shape to which conductive wiring patterns 24 are connected via the pad body 33 is not at all limited to the shape of the pad 23 used in this embodiment. For example, conductive wiring patterns 24 can be connected to the pad body 33 of the pad 23 conforming to the first or second embodiment.
A portable computer 81 is explained by referring to
The enclosure 4 of the portable computer 81 houses a printed circuit board 82 inside. As shown in
In this embodiment, explanation is given using a BGA package as an example of the semiconductor package 83. It should be noted, however, that the semiconductor package 83 is not at all limited to a BGA package, and a LGA or other package may also be used, for example. In other words, bumps 42 need not be attached to the semiconductor package, but they can also be provided on the printed wiring board.
The semiconductor package 83 has a package body 84. The package body 84 includes an insulating substrate 21, a plurality of pads 23, a plurality of conductive wiring patterns 24, and a solder resist 26.
As shown in
The pads 23 are arranged in such a way that their gaps g are aligned side by side. The conductive wiring patterns 24 are laid out so that they run alongside the gaps g. As shown in
The semiconductor package 83 is installed on the printed wiring board 11. Bumps 42 are provided on the bottom surface of the package body 84. The bumps 42 are connected to the pads 23 on the printed wiring board 11. As the bumps 42 are connected to the pads 23 on the printed wiring board 11, the semiconductor package 83 is electrically connected to the printed wiring board 11 via the bumps 42.
When the semiconductor package 83 of this configuration is used, the bonded state of each bump 42 with a pad 23 is affected to a lesser extent by the sizes and number of conductive wiring patterns 24 connected to the pad 23, and a stable bonded state can be formed as a result. In other words, providing extension parts 34 on the pad 23 reduces the rate of change in the pad area due to the effect of any conductive wiring pattern 24 connected to the pad. This makes the bonded state of bump 42 roughly uniform among individual pads 23. According to the semiconductor package 83 conforming to this embodiment, conductive wiring patterns 24 are connected to extension parts 34 and therefore the area of each pad does not change due to the effect of any conductive wiring pattern 24 connected to it, and consequently a more uniform bonded state can be achieved.
The pad shape of the semiconductor package 83 is not at all limited to the shape of the pad 23 used in this embodiment. For example, the shape of any of the pads provided on the printed wiring boards 11, 53, 73 that conform to the first, second and fourth embodiments may be adopted.
The above explained the portable computers 1, 51, 61, 71, 81 conforming to the first through fifth embodiments. It should be noted, however, that the embodiments of the present invention are not at all limited to these portable computers. The configuration conforming to each embodiment may be comprised of any combination of elements as deemed appropriate.
For example, the shape of the pad 23 need not be circular. For instance, a rectangular pad 23 like the one shown in
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-94878 | Mar 2006 | JP | national |
