1. Field of the Invention
The present invention relates generally to a mounting board on which a semiconductor chip is to be mounted by flip-chip bonding and to a semiconductor device having a semiconductor chip mounted on the mounting board.
2. Description of the Related Art
With recent improvements in the performance of semiconductor chips due to the miniaturization of their circuits, mounting boards for mounting semiconductor chips have also been required to have finer wiring. Therefore, various proposals for miniaturization have been made on the structure of connection pads, which are part of the mounting board to be connected to a semiconductor chip. In the following, first, a typical example of the conventional mounting of a semiconductor chip on the mounting board is given, and then a description is given of a structure accommodating the miniaturization of a semiconductor chip on the part of the mounting board.
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In the above-described mounting of the semiconductor chip 1, if the circuit of the semiconductor chip 1 is further miniaturized (the pitch of the connection bumps 2 becomes finer)., this should be accommodated on the part of the mounting board 3 (connection pads 4).
For example, there is a problem in that the miniaturization of the circuit of a semiconductor chip causes solder used in a connection part of the semiconductor chip and a mounting board to come into contact with solder used in an adjacent connection part, thereby increasing the probability of the occurrence of a short circuit in the circuit of the semiconductor chip. Therefore, for example, a mounting board structure accommodating the miniaturization of a semiconductor chip as shown below is proposed.
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A semiconductor chip is to be connected to the connection pads 4A by flip-chip bonding. Each of the connection pads 4A is made up of a narrow first region 4a and a second region 4b to which a corresponding connection bump of the semiconductor chip is to be connected. The second region 4b is greater in width than the first region 4a.
The surface of each connection pad 4A is coated with solder. When the solder is melted, the melted solder moves from the first region 4a to concentrate in the second region 4b because of its surface tension.
Therefore, it is possible to reduce the thickness of the solder coating layer formed on the first region 4a while ensuring a necessary thickness of the solder coating layer on the second region 4b in the connection pad 4A. Accordingly, it is possible to prevent the solder from short-circuiting adjacent connection parts (see Patent Document 1).
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By the above-described structure, melted solder is prevented from spreading to the insulating layer side.
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Reference may also be made to Patent Document 3 for related art.
[Patent Document 1] Japanese Laid-Open Patent Application No. 2000-77471
[Patent Document 2] Japanese Laid-Open Patent Application No. 2001-284783
[Patent Document 3] Japanese Laid-Open Patent Application No. 2002-329744
In the case of achieving further miniaturization of the circuit of a semiconductor chip, further accompanying miniaturization of mounting pads, and narrower pitches, however, it may be difficult to prevent the occurrence of a short circuit due to the contact of adjacent solder coatings even with the mounting board 10 or 10A.
In particular, if the pitch of the connection pads is less than or equal to 50 μm, it may be difficult to prevent the occurrence of a short circuit due to solder contact by the above-described methods.
Embodiments of the present invention may solve or reduce the above-described problem.
According to one embodiment of the present invention, there are provided a mounting board in which the above-described problem in solved, and a semiconductor device having a semiconductor chip mounted on the mounting board.
According to one embodiment of the present invention, there are provided a mounting board that accommodates the miniaturization of the circuit of a semiconductor chip, and a semiconductor device having a semiconductor chip mounted on the mounting board.
According to one embodiment of the present invention, there is provided a mounting board on which a semiconductor chip having a plurality of connection bumps is to be mounted by flip-chip bonding, the mounting board including: a plurality of connection pads to be electrically connected to the corresponding connection bumps, the connection pads having respective surfaces coated with solder; and an insulating layer configured to surround the connection pads and isolate the connection pads from each other, wherein each of the connection pads has a first region, and at least one second region to be connected to a corresponding one of the connection bumps, the first region having a surface substantially as high as a surface of the insulating layer and the at least one second region having a surface lower than the surface of the first region.
The above-described mounting board allows a semiconductor chip having a miniaturized circuit to be mounted thereon.
According to one embodiment of the present invention, there is provided a semiconductor device including: a semiconductor chip having a plurality of connection bumps; and a mounting board on which the semiconductor chip is mounted by flip-chip bonding, wherein the mounting board includes a plurality of connection pads to be electrically connected to the corresponding connection bumps, the connection pads having respective surfaces coated with solder; and an insulating layer configured to surround the connection pads and isolate the connection pads from each other, wherein each of the connection pads has a first region, and at least one second region to be connected to a corresponding one of the connection bumps, the first region having a surface substantially as high as a surface of the insulating layer and the at least one second region having a surface lower than the surface of the first region.
The above-described semiconductor device allows a semiconductor chip having a miniaturized circuit to be mounted therein.
Thus, according to embodiments of the present invention, it is possible to provide a mounting board accommodating the miniaturization of the circuit of a semiconductor chip and a semiconductor device having a semiconductor chip mounted on the mounting board.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:
A description is given below, with reference to the accompanying drawings, of embodiments of the present invention.
[First Embodiment]
Each connection pad 104 includes a first region 104A and a second region 104B. The second region 104B is to be connected to a corresponding one of the connection bumps of the semiconductor chip to be mounted. The surface of the first region 104A is positioned substantially as high as the surface of the insulating layer 103. That is, the surface of the first region 104A and the surface of the insulating layer 103 are in substantially the same plane. The surface of the second region 104B is lower than the surface of the first region 104A. That is, the surface of the second region 104B is lower than the surface of the insulating layer 103. In other words, the surface of the second region 104B is positioned closer to the opposite surface of the insulating layer 103 than the surface of the first region 104A is. In other words, the surface of the second region 104B is vertically positioned, or positioned in the direction toward the semiconductor chip to be mounted, between a first surface of the insulating layer 103 formed in substantially the same plane as (substantially on a level with) the surface of the first region 104A and a second surface of the insulating layer 103 opposing the first surface. Further, the first region 104A and the second region 104B have substantially the same width. Accordingly, the connection pad 104 has a belt-like shape.
In a plan view, the connection pad 104 has a substantially rectangular (strip-like) shape. Further, the concave second region 104B is formed in the substantial center of the connection pad 104. Alternatively, the concave second region 104B may be formed in a part of the connection pad 104 other than the center thereof. The first region 104A is formed on each side of the second region 104B.
Therefore, when the solder with which the connection pad 104 is coated is melted, it is possible to efficiently concentrate the melted solder in the second region 104B to be connected to a connection bump of the semiconductor chip. Accordingly, unlike the above-described mounting boards 10 and 10A, there is no need to increase the width of part of a connection pad to be connected to a semiconductor chip.
Thus, according to the mounting board 100 of this embodiment, it is possible to make the width of a connection pad smaller and the pitch for disposing connection pads narrower than conventionally. Accordingly, it is possible to mount a semiconductor chip having a miniaturized circuit on the mounting board 100 by forming connection pads accommodating the miniaturized circuit of the semiconductor chip and a narrow pitch of the connection bumps of the semiconductor chip.
Further, a solder mask layer 107 having an opening is formed on the insulating layer 103, and each connection pad 104 is formed so as to have part thereof including the second region 104B exposed through the opening.
After forming the coating layer 105, the connection pad 104 (mounting board 100) is heated so as to melt the coating layer 105 (by reflowing), so that the coating layer 105 is reduced in thickness in the first region 104A, and is thicker in the second region 104B than in the first region 104A. That is, the coating layer 105 has a thickness suitable for mounting a semiconductor chip (connecting a connection bump) in the second region 104B.
According to the mounting board 100, for example, it is possible to form fine patterns where the connection pads 104 each has a width of approximately 10 to 15 μm and are disposed with a pitch of approximately 20 to 35 μm, so that it is possible to mount a semiconductor chip by flip-chip bonding without adjacent patterns being short-circuited through solder.
Preferably, the first region 104A is, for example, approximately 50 to 100 μm in length, and the second region 104B is, for example, approximately 50 μm in length.
For example, the connection pads 104 may be formed of a metal material such as Cu, and the insulating layer 103 may be formed of a so-called build-up resin (epoxy resin, polyimide resin, etc.). However, the connection pads 104 and the insulating layer 103 are not limited to those materials.
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Each of the interconnection parts 108 includes a via plug 108A connected to a corresponding one of the connection pads 104, and a pattern interconnection 108B formed on the bottom-side surface of the insulating layer 103 and corrected to the via plug 108A. Further, a solder mask layer 109 is formed to cover the bottom-side surface of the insulating layer 103, part of the pattern interconnection 108B, and the via plug 108A.
A coating layer 110 of solder is formed on part of the pattern interconnection 108B exposed through a corresponding opening of the solder mask layer 109. The interconnection part 108 is connectable to a target of connection such as a motherboard through the coating layer 110.
Further,
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In the semiconductor device 200, it is possible to make smaller the width of each connection pad 104 connected to the semiconductor chip 201 and to make narrower the pitch with which the connection pads 104 are disposed than conventionally. Accordingly, it is possible to mount the semiconductor chip 201 having a miniaturized circuit on the mounting board 200 by forming the connection pads 104 accommodating the miniaturized circuit of the semiconductor chip 201 and a narrow pitch of the connection bumps 202 of the semiconductor chip 201.
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Further, it is preferable to form a resist layer 115 of dry film resist on the interconnection parts 108 in order to protect the interconnection parts 108.
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Likewise, the-solder mask layer 109 having openings 109A is formed so as to cover the interconnection parts 108. Part of each pattern interconnection 108B is exposed through the corresponding opening 109A.
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According to the semiconductor device 200, the width W of each connection pad 104 is, for example, 10 μm, and the pitch P of the connection pads 104 (connection bumps 202) is, for example, 30 μm, so that the semiconductor chip 201 corresponding to a miniaturized semiconductor circuit can be mounted.
[Second Embodiment]
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This corresponds to the case where the connection bumps of a semiconductor chip to be mounted are disposed alternately in different rows in a so-called staggered manner. Alternate disposition of the connection bumps of a semiconductor chip as described above is preferable because this disposition makes it possible to narrow the pitch of the connection bumps. In this case, it is also possible to dispose the second regions 104B of the connection pads 104 alternately in a staggered manner correspondingly. However, alignment of a mask is difficult in this case. Therefore, it is preferred to form the two second regions 104B adjacently in each connection pad as described above.
The materials of and the methods of forming the connection pads, insulating layer, and the connection bumps shown in the above-described embodiments are merely examples, and the mounting boards and the semiconductor devices according to the above-described embodiments can be formed using other materials and methods.
According to one embodiment of the present invention, there is provided a mounting board on which a semiconductor chip having multiple connection bumps is to be mounted by flip-chip bonding, the mounting board including multiple connection pads to be electrically connected to the corresponding connection bumps, the connection pads having respective surfaces coated with solder; and an insulating layer configured to surround the connection pads and isolate the connection pads from each other, wherein each of the connection pads has a first region, and at least one second region to be connected to a corresponding one of the connection bumps, the first region having a surface substantially as high as a surface of the insulating layer and the at least one second region having a surface lower than the surface of the first region.
The above-described mounting board allows a semiconductor chip having a miniaturized circuit to be mounted thereon.
Additionally, it is preferable in the mounting board that each connection pad have multiple second regions formed therein because this facilitates mounting of a semiconductor chip having a miniaturized circuit.
According to one embodiment of the present invention, there is provided a semiconductor device including a semiconductor chip having multiple connection bumps; and a mounting board on which the semiconductor chip is mounted by flip-chip bonding, wherein the mounting board includes multiple connection pads to be electrically connected to the corresponding connection bumps, the connection pads having respective surfaces coated with solder; and an insulating layer configured to surround the connection pads and isolate the connection pads from each other, wherein each of the connection pads has a first region, and at least one second region to be connected to a corresponding one of the connection bumps, the first region having a surface substantially as high as a surface of the insulating layer and the at least one second region having a surface lower than the surface of the first region.
The above-described semiconductor device allows a semiconductor chip having a miniaturized circuit to be mounted therein.
Additionally, it is preferable in the semiconductor device that each connection pad have multiple second regions formed therein because this facilitates mounting of a semiconductor chip having a miniaturized circuit.
Additionally, it is preferable in the semiconductor device that the solder be formed to be thicker in the second region than in the first region because this increases the amount of solder in the connection parts of the semiconductor chip and the mounting board so as to ensure electrical and mechanical connections.
Thus, according to embodiments of the present invention, it is possible to provide a mounting board accommodating the miniaturization of the circuit of a semiconductor chip and a semiconductor device having a semiconductor chip mounted on the mounting board.
The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.
The present application is based on Japanese Priority Patent Application No. 2005-299206, filed on Oct. 13, 2005, the entire contents of which are hereby incorporated by reference.
Number | Date | Country | Kind |
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2005-299206 | Oct 2005 | JP | national |